Hepatitis Ebook

Alternative Hepatitis C Treatments

The therapeutic goals of Natural treatment for Hepatitis C are as follows: Decrease iral load Normalize liver enzyme levels. Enhance/regulate immune system function. Strengthen and promote healthy liver function. Protect the liver, prevent further damage. Virological response; i.e. viral clearance, viral reduction or elimination of the virus. Starve the virus by limiting levels of iron. Optimizing cellular levels of glutathione in the body, making detoxification of the liver possible and enhancing the immune system. Stimulate regeneration of the damaged liver cells. Use of antioxidants to combat the effects of free-radicals generated by the virus. Reduce inflammation. Slow viral replication. Replace all of the inflammation-damaged liver cells. Regulate immune function/prevent auto-immune problems. Cancer preventative measures. Reverse fibrosis to prevent and improve cirrhosis

Alternative Hepatitis C Treatments Summary

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Treatment of Chronic Hepatitis B

Prior to the introduction of specific antiviral therapeutics, persistent HBV infection was treated with interferon, with mixed success. In some studies, up to one-third of treated individuals cleared the virus, but the treatment was rather less successful in certain populations, particularly individuals from the Far East. Interferon seems to work by modulating the immune response of the host, rather than a direct antiviral effect, and was found to be most successful in individuals who had evidence of hepatitis or, in other words, already were mounting a cellular immune response to the virus. Figure 5 Expression of the HBV core ORF. The pregenomic RNA is translated from the second initiation codon in the ORF to yield HBcAg. The precore RNA is translated from the upstream initiation codon to p25, which is processed to HBeAg. The arrow indicates the position of the most common precore mutation, changing a tryptophan to a termination codon. Reproduced from Harrison TJ (2006) Hepatitis B...

The Amplicor HCV Monitor 20 and Cobas Amplicor HCV Monitor 20 Test Roche Diagnostic Systems

Based on reverse transcription polymerase chain reaction (RT-PCR), the Amplicor HCV Monitor test (Roche Diagnostic Systems) was developed. 5 Recently, an improved version 2.0 was introduced, which achieved an equivalent quantitation of each genotype over the quantitative range (5 x 102 to 5 x 105 copies of RNA mL). 6,7 HCV RNA is extracted from plasma by chaotropic salt and is then precipitated by isopropanol. Both RT and PCR of RNA are accomplished in one tube using the recombinant thermostable DNA polymerase (rTth), which offers both reverse transcriptase activity, forming a cDNA from the RNA target sequence of the 5' UTR, and polymerase activity for amplification of the cDNA under appropriate conditions. An internal quantification standard shows the same primer-binding sites as the target but with a changed internal sequence, which allows binding to special detection probes. This allows quantification after a series of dilutions at the end of the assay. To meet the needs of routine...

The Hepatitis B Vaccines

The hepatitis B vaccines contain HBsAg and are given via an intramuscular injection to stimulate a protective anti-HBs response. The first-generation (so-called 'plasma derived') vaccine was produced by purifying HBsAg from donated blood. Despite some worries that blood-borne viruses (particularly human immunodeficiency virus (HIV)) potentially might contaminate particular batches, this method of vaccine production is safe provided that manufacturing protocols, including steps that inactivate potential infec-tivity, are adhered to strictly. Even today, plasma-derived vaccines constitute the majority of doses given worldwide. Currently, most doses of hepatitis B vaccine given in the West are produced by expression of HBsAg in yeast (Saccharomyces cerevisiae), and several vaccines based on expression in mammalian cells also have been licensed. Most countries worldwide have now introduced universal immunization of infants. Although the vaccine may be incorporated into the Expanded...

HCV Replication Cycle

HCV infection starts by binding the envelope glycoprotein E1 E2 complex on the surface of the virus particle to its cognate receptor(s) presumably leading to clathrin-mediated endocytosis and a subsequent fusion step from within an acidic endosomal compartment (Figure 3). Cellular factors implicated in virus binding and entry are glycosaminoglycans, scavenger receptor class B type 1 (SR-B1), CD81, and low-density lipoprotein (LDL) receptor. However, for most of these factors, the precise role is not well understood and one or several additional factors may be required for productive entry. Upon release of the RNA genome, the polyprotein is expressed by IRES-dependent translation occurring at the rough endoplasmic reticulum (rER) where host cell signal peptidases, signal peptide peptidases, and viral proteases catalyze polyprotein cleavage.

Differentially Expressed Genes Associated With Hepatitis B Virus HBx and MHBs Protein Function in Hepatocellular

HBx and MHBs' products from hepatitis B virus-DNA (HBV-DNA), which become transcriptional transactivators of cellular and viral genes, are known to play causative roles in the development of hepatocellular carcinoma (HCC). However, the biomolecular mechanism(s) for their roles in hepatocarcinogenesis in vivo remain poorly understood. To identify authentic cellular genes involved in HBx and MHBsl-transactivated carcinogenesis, we used mRNA differential display polymerase chain reaction (DD-PCR). We examined HBx and MHBs-positive or -negative HCC, which had chromosomally integrated HBV DNA, vs nontumor tissues, respectively, and differentially expressed genes in either type of HCC were identified and compared with each other. Using 240 different combinations of three one-base anchored oligo-dT primers and 80 arbitrary 13mers, 16 genes were differentially expressed in the HBx and MHBs-positive HCC including Ro RNA hY1, glutamine synthetase, factor H homologue 3' end, voltage-dependent...

Progress On New Hepatitis C Virus Targets Ns2 And Ns5a

Hepatitis C virus (HCV) is a major global health problem, affecting about 170 million people worldwide. Chronic infection can lead to cirrhosis and liver cancer. The replication machine of HCV is a multi-subunit membrane associated complex, consisting of nonstructural proteins (NS2-5B), which replicate the viral RNA genome. The structures of NS5A and NS2 were recently determined. NS5A is an essential replicase component that also modulates numerous cellular processes ranging from innate immunity to cell growth and survival. The structure reveals a novel protein fold, a new zinc coordination motif, a disulfide bond and a dimer interface. Analysis of molecular surfaces suggests the location of the membrane interaction surface of NS5A, as well as hypothetical protein and RNA binding sites. NS2 is one of two virally encoded proteases that are required for processing the viral polyprotein into the mature nonstructural proteins. NS2 is a dimeric cysteine protease with two...

Hepatitis Introduction

Hepatitis is the inflammation of the liver usually caused by a virus. Four viruses that may cause it are hepatitis A (HAV), hepatitis B (HBV), hepatitis D (HDV) and hepatitis non-A, non-B (NANB). Most common of the types found in children is hepatitis A which is transmitted by the fecal-oral route. The incidence in children is increased in those living in crowded housing. The disorder is usually self-limiting with resolution within 2 to 3 months or may develop into chronic hepatitis. Symptomology varies with severity of the disease.

Hcv Ns5a

NS5A is an active component of the HCV RNA replicase, a pivotal regulator of replication, and a modulator of numerous cellular processes spanning from innate immunity to apoptosis and disregulated cell growth.29'41 It exists as a serine phosphoprotein present in hypo- (56 kDa) and hyper-phosphorylated (58 kDa) forms. An amphipathic a-helix at its N terminus promotes association with cellular membranes.4'8'32 Following this helix, NS5A is organized into three domains (Fig. 2A)40 The N-terminal domain (domain I) coordinates a single zinc atom per protein molecule.40 Mutations disrupting either the membrane anchor8,32 or zinc binding40 are lethal for HCV RNA replication. NS5A interacts with other viral components of the replicase7 and has been shown to modulate NS5B polymerase activity in vitro.37'38 NS5A domain II and the region connecting domain I and II are hotspots for adaptive mutations that can enhance replication in cell culture by more that 10,000-fold.2'26 Such highly adaptive...

Hepatitis Viruses

Hepatitis, or inflammation of the liver, can be caused by many different viruses and chemical substances. Viruses may cause acute infection (hepatitis A virus) or acute infection with the possibility for chronic liver infection leading to cirrhosis and hepatocellular carcinoma. Two major causative agents of acute and chronic disease are hepatitis B (HBV) and hepatitis C (HCV) viruses. The World Health Organization estimates the worldwide population of HBV carriers at about 350 million, with 75 of these living in the Far East. While less than 0.5 of the population of the USA and about 1 of that of Europe may carry HBV, lOand 12 may be carriers in Southeast Asia and Africa, respectively. With the identification of HCV as the cause of most of the non-A, non-B hepatitis, and with the development of immunoassays for detection of antibody to HCV, it has become clear that HCV is a major worldwide problem. The CDC estimate that there are about 150 000 new cases in the USA each year, with 1.5...

Hepatitis

Of hepatitis are self-limiting and resolve without complications. Hospitalization is required only when symptoms are severe, persistent, or debilitating. Approximately 20 of acute hepatitis B and 50 of hepatitis C cases progress to a chronic state. In Americans, 5 to 10 of patients with hepatitis have hepatitis B virus (HBV) infections. In third world countries, the rates are much higher. The most serious complication of hepatitis is fulminant hepatitis, which occurs in approximately 1 of all patients and leads to liver failure and hepatic encephalopathy and, in some, to death within 2 weeks of onset. Other complications include a syndrome that resembles serum sickness (muscle and joint pain, rash, angioedema), as well as cirrhosis, pancreatitis, myocarditis, aplastic anemia, or peripheral neuropathy.

Hepatitis D Virus

HDV merits a brief mention because of its particular association with HBV. As noted above, a novel antigen, termed delta, was discovered in patients with hepatitis B and this turned out to be the nucleocapsid protein of HDV. The HDV genome is a single-stranded circle of RNA that resembles the viroids and virusoids of plants it is believed to be replicated by the host RNA polymerase II, with cleavage and rejoining of the circle mediated by a ribozyme activity. Unlike the viroids and virusoids, HDV was first discovered in Italy and is found in the Mediterranean area, reportedly with a declining prevalence, and also in the Far East and South America. The virus may be acquired as a coinfection with HBV or by super-infection of someone already HBsAg-positive. In both cases, disease may be more severe than with HBV alone, and chronic delta hepatitis may progress to cirrhosis more frequently, and more rapidly, than chronic hepatitis B. The hepatitis B vaccine also protects against...

Hcv Rna Quantitation

Quantitation of HCV RNA by bDNA technology is possible with the commercial VERSANT HCV RNA 3.0 assay. The performance characteristics of this test were established in our laboratory during the so-called ''beta trials'' before licensing and are given in Table 1. 4 Our findings were essentially confirmed by other studies, 11,12 and showed that the assay, from an analytical point of view, can be used as a routine tool for HCV RNA quantitation in clinical laboratory settings. Table 1 Analytical performance characteristics of VERSANT HCV RNA 3.0 assay Table 1 Analytical performance characteristics of VERSANT HCV RNA 3.0 assay

HCVHost Interaction

Several cellular proteins appear to contribute to HCV replication. For example, the ubiquitously expressed human vesicle-associated membrane protein-associated protein A (VAP-A) and its isoform VAP-B were identified as interaction partners of NS5A and NS5B. NS5A hyperphosphorylation seems to disrupt the VAP-A association and thereby negatively regulates HCV RNA replication. It is thought that VAP-A directs HCV nonstructural proteins to cholesterol-rich, detergent-resistant membranes, which are the presumed sites of HCV RNA replication. Another host cell factor interacting with NS5A is FBL-2 belonging to the family of proteins that contain an F box and multiple leucine-rich repeats. FBL-2 is modified by geranylgeranylation which is important for NS5A interaction. FBL-2 appears to be required for HCV RNA replication. Likewise, Cyclophilin B (CyPB), a cellular protein interacting with the NS5B RdRp, seems to contribute to replication of genotype 1 isolates by promoting RNA-binding...

Hepatitis B

Hepatitis B, or serum hepatitis, is spread mainly through contaminated blood, often from unsterilized needles shared by drug users or used for tattoos or ear or body piercing. The virus can also be transmitted sexually. Over 100,000 people are infected yearly in the United States, but this number is decreasing due to the recent introduction of a vaccine. In addition to the initial disease, which is more severe than hepatitis A (more liver damage and fatality rate of 10 ), those infected are at higher risk of liver cancer.

Transmission and Tissue Tropism

Transmission in outbreaks in daycare centers and nursing homes. Infection may also occur via contaminated water or foods, particularly shellfish. Most human and animal astroviruses are associated with symptoms of gastroenteritis, and replication has been documented in the gastrointestinal tract. A noteworthy exception is duck hepatitis virus which has been detected by EM in the livers of animals with histologic evidence of hepatitis.

Bio Robot Workstations

For the extraction of hepatitis C virus RNA, it was shown that it is possible to achieve a detection level of 12.8 IU mL (95 confidence). Cross-contamination studies have confirmed that the use of the BioRobot 9604 does not pose a detectable contamination risk. 2 For hepatitis B virus detection, Mitsunaga et al. describe that it was possible to quantify DNA in all samples extracted by the BioRobot 9604 which contained more than 500 genome equivalents mL. Extraction of 96 samples could be completed within 2 hr. 3

Taxonomy and Classification

Early structure analyses of BVDV and CSFV indicated a virion architecture similar to the classic toga-viruses. Since there was no apparent insect vector for these viruses, the term 'nonarthropod-borne toga-viruses' was created to include BVDV, BDV, CSFV, equine arteritis virus, lactate dehydrogenase virus and rubella. With the establishment of the antigenic relationship of BVDV, BDV and CSFV, a new genus, Pestivirus, was created within the family Togaviridae in 1982. Data on the genomic structure of the pesti-viruses indicated a closer relationship to viruses such as yellow fever virus and West Nile virus, and in 1991 the pestiviruses were reclassified in the genus Pestivirus within the Flaviviridae family. Yellow fever virus is in the genus Flavivirus. The hepatitis C group of viruses are also included within this family under the genus 'Hepatitis C-like viruses'.

Future Perspectives

See also Bovine diarrhea virus and Border disease virus (Flaviviridae) Chikungunya, O'nyong nyong and Mayaro viruses (Togaviridae) Dengue viruses (Flaviviridae) Encephalitis viruses (Flaviviridae) Tick-borne encephalitis and Wesselsbron viruses Equine encephalitis viruses (Togaviridae) Hepatitis C virus (Flaviviridae) Hog cholera virus (Flaviviridae) Japanese encephalitis virus (Flaviviridae) Rubella virus (Togaviridae) Sindbis and Semliki Forest viruses (Togaviridae).

Gender Ethnicracial And Life Span Considerations

Cirrhosis is most commonly seen in the middle-aged population it is the fourth leading cause of death in the population that is 35 to 55 years of age. It is more common in males than in females. Although the cause is obscure, liver disease appears to be more prevalent in preterm infants who have minimum enteral feedings and who were begun on total parenteral nutrition (TPN) at an early age. Hepatitis C is more common in minority populations, such as African Americans and

Pathology and Histopathology

Macroscopic lesions are seen only rarely as a result of infection by AEV. Histological changes in the central nervous system include lymphocytic perivascular cuffing, evidence of gliosis and axonal-type neuronal degradation. In addition, hyperplasia of the lymphoid follicles in visceral tissue occurs. The livers of ducks suffering from duck virus hepatitis are enlarged and contain hemorrhages. The spleen is often also enlarged and the kidneys may be swollen. Histological signs include hepatic necrosis, varying degrees of inflammatory cell infiltration and proliferation of bile duct epithelium. Gross lesions are observed in the liver and pancreas of turkeys suffering from turkey virus hepatitis. The histological changes include necrotic foci, hemorrhage and mononuclear foci. Focal parenchymal foci of necrosis may also be observed in the pancreas.

Discharge And Home Healthcare Guidelines

Teach the patient and significant others about the disorder and that it is unlikely that it will recur in the future. If the patient required blood component therapy, provide information about the risk of hepatitis or human immunodeficiency virus (HIV) transmission. Check with the patient's obstetrician to determine if the patient can nurse the infant and resume unprotected sexual relations. Provide discharge instructions related to the patient's primary diagnosis. Teach the patient to notify the physician of any uncontrollable bleeding or syncope.

Clinical Features of Infection

Most HBV infections are asymptomatic with mild serum alanine aminotransferase (ALT) changes that resolve, although clinically apparent acute hepatitis and occasionally fulminant hepatitis with hepatic failure and death can occur. The severity of acute viral hepatitis B appears to be related to age of infection (young children generally have milder disease than adults), the infecting virus dose (higher doses appear to result in shorter incubation period and generally more severe hepatitis), and immunosuppression which may be associated with mild disease and frequent persistent infection. Chronic HBV infection is most often asymptomatic ('healthy carriers') and symptomatic chronic active hepatitis with periods of fever, malaise and hepatic pain is much less common. In highly endemic regions of the world such as eastern Asia, most HBV infections occur in newborns or young children and are relatively asymptomatic many of these infections become persistent and remain silent for many years...

Hare Fibroma Virus see Poxviruses

Nassal M (1996) Hepatitis B virus morphogenesis. Curr. Top. Microbiol. Immunol. 214 297. Seeger C and Mason WS (1996) Replication of the hepatitis virus genome. In dePamphilis E (ed.) DNA Replication in Eukaryotic Cells, p. 815. Cold Spring Harbor Cold Spring Harbor Laboratory Press. Avian Hepatitis B Virus

Geographic and Seasonal Distribution

From the wild mallard (Anas p. platyrhynchos) and, despite wide differences in appearance due to domestication, belong to a single species. Duck hepatitis B virus has been found both in the wild mallard and in domestic flocks of this species throughout the world, but not in Muscovy ducks. The incidence of chronic infection in individual flocks can range from zero to 100 . Infections are primarily acquired congenitally, by virus passed into the egg laid by a viremic duck. Transmission by this route leads to a chronic viremia that is probably lifelong. Horizontal spread of infection may also occur. Since the virus is blood-borne, horizontal spread presumably occurs through The geographic and seasonal incidence of the heron hepatitis B virus has not been described.

Serologic Relationships and Variability

There are currently no defined subtypes or serotypes of duck hepatitis B virus, though there are monoclonal antibodies which distinguish between different amino acid sequences of the surface antigen. The amount of variation in nucleotide sequence in the published sequences of duck hepatitis B virus (1.2 11.6 ) appears to resemble that of hepatitis B virus subtypes (8 10 ). Sequences from three genomes cloned from ducks from the USA and Germany appear more closely related to each other (1.2-5.9 variation) than to five sequences cloned from ducks Five sequences of heron hepatitis B virus have been published. Up to 7 sequence diversity has been found in the heron hepatitis B virus isolates. The prototype heron hepatitis B virus sequence differs from duck hepatitis B virus sequences by 21.6 , somewhat more than the 16.4 variation between the woodchuck and ground squirrel hepatitis viruses.

Prevention and Control

Because duck hepatitis B virus has not been demonstrated to cause morbidity, mortality or even minor adverse effects on the health and viability of domestic ducks, a serious effort at primary prevention (i.e. vaccination) has not seemed warranted. However, because the in vivo replication of the duck hepatitis B virus is virtually identical to that of human hepatitis B virus, this animal model has been used to study antiviral agents and strategies that might eventually be tried in humans. Selected nucleoside analogues have been shown to have good specificity against virus DNA synthesis, mediated by a viral encoded reverse transcriptase, and to cause a reduction of viremia and a drop in hepatic levels of replicating viral DNA.

Properties of the Viral Proteins

The four protein-coding regions of the mammalian hepadnaviruses are translated into seven known proteins (Fig. 1). The core ORF codes for the 21 kDa viral capsid protein, also called hepatitis B core antigen (HBcAg) and the 16-18 kDa precore polypeptide, termed hepatitis B e-antigen (HBeAg). The HBcAg is the most highly conserved polypeptide among the mammalian hepadnaviruses showing 68 amino acid homology between HBV and GSHV (GSHcAg) and 92 between GSHV and WHV (WHcAg). It is a cytoplasmic and nuclear phospho-protein with a basic C-terminus that is essential for the packaging of viral RNA. Core polypeptide monomers form dimers that assemble into spherical shells with icosahedral symmetry consisting of 120 dimer subunits. The formation of these dimers is mediated by two long alpha helices that form spikes on the surface of nucleocapsids. Dimers are further stabilized through the formation of two homologous intermolecular disulfide bridges.

Host Range and Virus Propagation

The recognized host range of HCV is quite limited. In addition to humans, the virus can be transmitted to chimpanzees and possibly to other greater and lesser Evidence has been obtained for replication of HCV in chimpanzee hepatocytes that were infected in vivo and then removed and maintained in culture. In addition, HCV has been reported to replicate in continuous lines of human T cells, B cells and monocytes. Such in vitro propagation systems have been used to study the neutralization of HCV by specific antibody and the inhibition of viral replication by antiviral agents such as interferon. However, all in vitro replication systems are difficult to reproduce and are limited in their application.

Pathology and Histopatholgy

The histologic changes in acute and chronic hepatitis C cannot generally be differentiated from those occurring in other types of viral hepatitis. The histologic changes in the liver during acute viral hepatitis are hepatic inflammation and hepatocellular necrosis. Inflammatory cells, principally lymphocytes and macrophages, are present in both the parenchyma and portal areas. Swelling and eosinophilic necrosis of hepatocytes are common. Chronic hepatitis C is characterized by inflammation (lymphocytes, macrophages and histiocytes) that is largely portal in distribution and hepatocellular necrosis that is typically periportal.

Classification and Properties

Caliciviruses were initially classified as picornaviruses with which they share a number of properties. However, the distinctive properties of caliciviruses led to the creation of a new family Caliciviridae. Human hepatitis E virus was originally considered to be a calicivirus because of apparent similarity in morphology but is now classified in the genus Hepevirus in an undefined family.

Physical Properties

The resistance of HCV to physical and chemical treatment is partly dependent on the physical state of the material containing the virus. For instance, in cell culture fluid the virus is inactivated more rapidly than in defribinated blood. The mean inactivation rate at 56 C was found to be between 1.6 and 2.7 log units in 30 min. Below pH 4 and above pH 11, viral infectivity is quickly lost. Because the virion envelope contains lipids, solvents such as chloroform and ether easily inactivate HCV. In pork, the virus remains infectious for months, whereas in the environment outside the host the virus is usually inactivated in a couple of days however, in liquid pig manure, HCV may survive for 2 weeks at 20 C and more than 6 weeks at 4 C. For disinfection, 1-2 sodium hydroxide is most suitable.

Primary Nursing Diagnosis

Replacement therapy and drug therapy may be used prophylactically or to control mild or major bleeding episodes. Desmopressin will raise factor VIII levels two- to threefold. Factor VIII replacement therapy is indicated for active bleeding or preparation for multiple tooth extractions or major surgery. Cryoprecipitate contains high levels of factor VIII and fibrinogen. Purified plasma-derived factor VIII concentrates are derived from large pools of plasma donors. Recent methods of screening and heating of these concentrates have greatly diminished the risk of contamination with the human immunodeficiency virus (HIV) but have little effect on the risk of hepatitis transmission. High-potency factor VIII preparations (those that are highly purified) are considered to be virtually virus-free. Recombinant factor VIII contains less risk of viral transmission but has a relatively high cost. A rule of thumb is that for every 1 unit kg infused, factor VIII levels will increase 2 . In an...

NS2 is a cysteine protease

Catalysis of a peptide bond by cysteine proteases proceeds through a well-characterized, charge relay network mechanism. The NS2 structure suggests that Glu 163 polarizes His 143 to deprotonate the cysteine side chain. The nucleophilic Cys 184 attacks the carbonyl of the scissile bond forming a negatively charged, tetrahedral transition state. Cleavage of the activated intermediate releases the N terminus of NS3 and creates an acyl-enzyme intermediate in which Cys 184 is covalently bonded to Leu 217. Hydrolysis of the acyl-enzyme intermediate forms the carboxylic acid of Leu 217 and restores the proton to Cys 184. Interestingly, Pro 164, which is adjacent to Glu 163 of the catalytic triad, has a c s-peptide conformation with the pyrrolidine ring lying on the same side as the carbonyl group of Glu 163 (Fig. 6). This proline residue is entirely conserved in HCV and the related GB virus sequences, implying that this position has an important

Evidence in favor of a NS2 dimer

A series of experiments in mammalian cells was designed to test whether NS2pro can form dimers with a functional composite active site in vivo. HCV full-length polyproteins containing either a H143A or a C184A mutation in the NS2 active site are defective in NS2-3 processing.1314 However, if a composite active site can form, co-expression of the two. mutant polyproteins should result in partial NS2-3 cleavage (see figure 3 in ref 27). Indeed, when HCV polyproteins with NS2 containing either a H143A or C184A mutation were co-expressed, NS2 and NS3 cleavage products were detected, indicating the formation of a functional composite active site. These data strongly support the NS2pro crystal structure and prove that NS2 can form dimers with composite functional active sites.

Commercial Application

Transgenic microbes have many commercial and practical applications, including the production of mammalian products. A company called Genentech was among the earliest and most successful commercial enterprises to use genetically engineered bacteria to produce human proteins. Their first product was human insulin produced by genetically engineered Escherichia coli. A variety of other human hormones, blood proteins, and immune modulators are now produced in a similar fashion, in addition to vaccines for such infectious agents as hepatitis B virus and measles.

DI Particles in Natural Infections

Nevertheless, association of a chicken influenza virus strain, efficiently producing DI particles, with an epidemic of low morbidity and low mortality, and conversely, a high-mortality epidemic associated with a strain free of DI particles, have been reported. Murine and feline leukemia virus strains causing immune deficiency syndromes are shown to contain predominantly replication-defective viral genomes before onset and during the development of the disease. The pathogenic-ity of some bovine and swine pestiviruses has clearly been associated with presence of DI RNAs in the animals. For the bovine viral diarrhea virus (BVDV), a pestivirus of the same family as hepatitis C virus, the presence of a particular DI RNA can turn noncytopathic virus into a fatal infectious agent. In plants, at least three examples of DI RNAs are described to be involved in infection modulation. Interestingly, depending on the types of viruses, DI RNAs can either attenuate or exacerbate the symptoms. DI RNAs...

Diagnostic Highlights

Viral hepatitis seriologies hepatitis A virus (HAV) hepatitis B virus (HBV) hepatitis C virus (HCV) hepatitis D virus (HDV) hepatitis E virus (HEV) (See Hepatitis, p. 410) If patient has hepatitis acute HAV positive anti-HAV IgM acute HBV anti-HBV IgM HB surface antigen acute HCV anti-HCV antibody, HCV RNA HDV anti-HDV IgM, HDV antigen HEV not available Non A Non B all tests negative Identify patients with hepatitis virus leads to markers such as immunoglobulins (IgG and IgM), antigens, antibodies

High Purity pdFIX Products

The use of enzyme replacement therapy (ERT), through administration of PCCs and pdFIX products, to treat hemophilia has no doubt enhanced the quality of life of the numerous recipients over the years, but has come at a considerable cost to many individuals receiving ERT. Numerous incidents from around the globe of HIV and hepatitis virus transmission through contaminated blood-clotting factor concentrates for hemophilia treatment have been reported 6,38-40 . Consequently, viral inactivation steps (Section 11.4.2.1) were introduced in the mid-1980s to eliminate the risk of transmission of HIV and hepatitis diseases. Although HIV, hepatitis viruses, and other enveloped viruses have not been transmitted since the introduction of these viral inactivation steps, concern remains about the possibility of nonenveloped viruses (such as parvovirus and hepatitis A) being transmitted 41,42 .

Steps to Increase Safety of Blood Derived Clotting Factor Products

Screening plasma for HIV, hepatitis (A, B, and C), parvovirus B19, syphillis, and cytomegalovirus is now a routine and standard practice. Traditionally, this was performed using enzyme-linked immunosorbent assay (ELISA) testing, an extremely sensitive method for detecting pathogens 42 . More rapid and sensitive nucleic acid amplification testing (NAT) has been introduced in most North American and European countries since the late 1990s. NAT offers an increased margin of safety for clotting factor concentrates 41 , in that it enables detection of hepatitis A and parvovirus, both of which are relatively recalcitrant to many viral inactivation technologies (see below). 3. Viral inactivation steps. Heat treatment was first introduced as a virucidal measure in the mid-1980s. Viruses have varying thermal sensitivities, with viruses such as HIV being more susceptible to heat treatment than the hepatitis viruses 41,43 . Heat treatment can result in significant denaturation of...

Global and International Surveillance

International surveillance can also be used for the detection of international outbreaks of food poisoning caused by the distribution of foodstuffs across a wide number of countries. An outbreak of hepatitis A in England was caused by frozen raspberries grown and frozen in another country and another outbreak of hepatitis A, this time in Czechoslovakia (before it became separate republics) was caused by strawberries used to make ice cream the strawberries had been imported from another Eastern European country. There are now well-established trans-European surveillance systems for salmonella infections and legionnaires' disease.

Neonatal Immunization

Induce immunity in neonates in the presence or absence of maternal antibodies makes this approach to vaccination extremely attractive, especially for diseases such as herpes simplex virus-2, human immunodeficiency virus (HIV), hepatitis B, group B strep, and chlamydia which often infect children during birth or shortly thereafter.

Pathological features

Depending on the results of the laboratory tests, those patients meeting the criteria above are classified into groups listed below. The following studies are suggested complete blood count, erythrocyte sedimentation rate, chemistry profile, creatine kinase, antinuclear antibody, thyroid functions, serum and urine immunoglobulin studies (to include either immunofixation electrophoresis or immunoelectrophoresis, and HIV and hepatitis serology. The list of laboratory studies is not comprehensive. For instance, in certain clinical circumstances, other studies may be indicated, such as phytanic acid, long-chain fatty acids, porphyrins, urine heavy metals, a-lipoprotein, p-lipoprotein, glucose tolerance test, imaging studies of the central nervous system, and lymph node or bone marrow biopsy. Classification of CIDP

Genome Organization

As noted above, all hepadnaviruses have a similar genome organization, despite the low DNA sequence identity between the mammalian and avian hepadnaviruses (40 ). The negative strand of the DHBV genome contains S-ORF, C-ORF, and P-ORF encoding the surface or envelope proteins, core and e antigen proteins, and polymerase protein, respectively (Figure 1). The DHBV genome was originally thought to contain only these three ORFs and to lack an ORF encoding a protein analogous to the X protein of the mammalian hepadnaviruses. It was subsequently discovered that avian hepadnaviruses, including HHBV and DHBV, have a fourth ORF, the X-ORF, which directs synthesis of a candidate X protein that is translated using an unconventional start codon. The significance of this observation is still unclear. Using woodchuck hepatitis virus (WHV), a close relative of HBV, the X gene was shown to be essential for successful WHV infections in vivo. In contrast, knockout of the X gene of DHBV did not alter...

Phylogenetic Information

Assigned species within the genus Avihepadnavirus include DHBV isolated from Pekin ducks (Anas domesticus) and HHBV from grey herons (Ardea cinerea). Many DHBV isolates have been found in domesticated ducks and, in the wild, in the mallard, the species from which most domesticated ducks are derived. Viruses less closely related to DHBV have been isolated from geese and other duck species and include the Ross's goose hepatitis B virus (RGHBV) from Ross's geese (Anser rossii), Mandarin duck hepatitis B virus (MDHBV) from Mandarin ducks (Aix galericulata), and the snow goose hepatitis B virus (SGHBV) from snow geese (Anser caerulescens). The stork hepatitis B virus (STHBV) has been isolated from white storks (Ciconia ciconia), with additional viruses isolated from demoiselle (Anthropoides virgo) and grey crowned cranes (Balearica regulorum) (Figure 4). By genome sequencing, HHBV and STHBV are the most distant from DHBV (Figure 4). HHBV was assigned as a species based both on genome...

Multiplex Nasba And

The Procleix human immunodeficiency virus-1 hepa-titis C virus (HIV-1 HCV) assay (Gen-Probe Inc.) detects both HIV- and HCV RNA in 1 tube. 8 The source of the reactivity can be determined by discriminatory assays using virus-specific probes. The HIV-1 HCV assay and the discriminatory assays are able to detect 10-13 copies of HIV-1 mL with 95 detection rates, and can detect 30 copies mL of HCV with 95 sensitivity. Furthermore,

Quantitative Nasba And Tma Applications

Quantitative nucleic acid amplification tests are gradually introduced into the laboratory. These assays are used for determination of the viral load of patients infected with blood-borne viruses such as human immunodeficiency virus type 1 (HIV-1) and hepatitis C virus (HCV). The conserved 5'NCR of HCV has been used as a target for the development of qualitative and quantitative ECL-based NASBA assays for genotypes 1a, 1b, 2, 3, 4, and 5. 16 When different assays were compared, the HCV NASBA-QT assay was over 10 times more sensitive than the bDNA assay, while the quantitative results of both assays were highly concordant. The HCV NASBA- QT assay was comparable in sensitivity with the HCV MONITOR assay (Roche Molecular Systems), but the latter yielded consistently lower values. 16 The qualitative COBAS AMPLICOR HCV version 2.0 PCR assay (Roche Molecular Systems) and the VERSANT HCV RNA qualitative assay (Bayer) were compared for analytical sensitivity and clinical perfor-mance. 17 The...

Replication And Infectivity

Mousepox (ectromelia) virus was first recognized as a mouse pathogen in 1930. Its pathogenesis differs from other orthopox viruses in that the virulent strains induce severe hepatitis in mice. It is highly infectious and can easily decimate mouse colonies in laboratories and breeding facilities. Vaccinating mice with the Vaccinia confers protection and has been used to control infections in mouse colonies. 7 No human infections have been reported due to ectromelia. However, the virus was useful as model to study the molecular basis of Orthopoxvirus virulence despite the fact that the mouse disease differs significantly from smallpox.

Multiple Biological Implications

The frequency of antibody-resistant mutants of RNA viruses is generally high (10 4-10 6 per infectious genome) both in cell culture and in vivo. The frequency of cytotoxic T lymphocyte-escape mutants is more difficult to determine but variations at specific T cell epitopes permitting virus escape in vivo have been documented in several systems, such as human hepatitis C virus, human immunodeficiency virus and lymphocytic choriomeningitis virus. Recent evidence suggests that the complexity of the mutant spectrum may influence the outcome of viral infections. The complexity of the coronavirus mouse hepatitis virus quasispecies may contribute to its pathogenic potential. Likewise, the nonresponse to treatment with interferon a in chronic hepatitis C virus infections may relate to the number of viral molecular species detected in the infected patients. Model experiments with the animal pathogen foot-and-mouth disease virus showed that indeed the repertoire of viral mutants that became...

Recombination in RNA Viruses

Sequence rearrangements were found in the following animal plus-strand RNA viruses picorna-viruses poliovirus and foot-and-mouth-disease virus (FMDV) in coronaviruses mouse hepatitis corona-virus (MHV) Sindbis alpha virus (SIN) flock house nodavirus (FHV) and in bacteriophages Q , and MS-2. Recombinants were found in bunyaviruses. Genetic rearrangements were also observed in other types of RNA viruses, including influenza virus, a minus-strand RNA virus, in retroviruses, and in double-stranded 06 bacteriophage. The following genomes of plant RNA viruses reveal RNA rearrangements alfalfa mosaic virus (AlMV), beet necrotic yellow vein virus (BNYVV), bromoviruses (see below), hordei-viruses, luteoviruses, nepoviruses, tobamoviruses, tobraviruses, tombusviruses and turnip crinkle car-movirus (TCV).

Never Ending Adaptation

Not all RNA virus populations show this dynamic of a continual change or even the diversity expected from quasispecies. Even in influenza virus A, avian isolates from natural host (waterfowl) can be genetically stable. Some RNA (and retro) viruses with high error rates can nevertheless maintain stable populations in specific hosts. For example, measles virus shows much less antigenic drift in human infections compared to influenza virus A. Hepatitis G virus (a human prevalent and distant relative of HCV) shows little variation in even isolated human populations. The filoviruses (Ebola virus and

Ligands Bound to Structured RNA

Similar methods have been applied to drug discovery efforts directed toward the 5'-UTR region of the hepatitis C virus (HVC) genomic RNA. This region contains a highly conserved structured RNA shown to be crucial for viral replication and translation, presumably by serving as an internal ribosomal entry site (IRES). Screening of a library of compounds for binding to a particular subdomain of the HCV IRES led to the identification of a hit having relatively weak affinity and modest selectivity for the target RNA. Using an MS-guided chemical optimization approach, this weak hit was elaborated into a lead structure which had sub-micro-molar affinity for the target RNA and activity in a cellular assay 28 .

Serological Relationship and Variability

Thus, many serotypes seem to coexist within the human population. The multiplicity of serotypes is in contrast to two other medically important picornaviruses, the polioviruses (three serotypes) and hepatitis A virus (a single serotype). Several serotypes fall into groups on the basis of low-level immunological crossreactivity with hyperimmune serum (HRV-36, HRV-58 and HRV-89 HRV-2 and HRV-49 for example), but it is not known whether this plays any role in protection from heterologous serotypes. These antigenic groups seem to correlate with close molecular relationships (Fig. 3).

Is DNA Hypomethylation Like DNA Hypermethylation Sometimes Associated with Tumor Progression

Hypermethylation of a subset of CpG islands is progressive in some types of cancer although sometimes this regional hypermethylation occurs very early in tumorigenesis, and other times it can serve as a significant indicator of survival.16,82, 3 Also, DNA hypomethylation is sometimes associated with tumor progression as seen in studies of repeated DNA sequences. In a study of 31 hepatocellular carcinomas by Itano and coworkers,84 the degree ofhypomethylation of either of two repetitive sequences was significantly correlated with postoperative recurrence of hepatocellular carcinoma and was a better predictor than conventional factors. These repeats were the above-mentioned 1.4-kb Y10752 NBL2 sequence that is found in the pericentromeric regions of chromosomes 13, 14, 21, and 950 and a 13-kb repeat present in tandem about 200 times on 8q21. Hypomethylation was determined by quantitating the corresponding radioactive spots relative to reference spots by restriction landmark genomic...

Genetics and Evolution

Since their are no known animal relatives of rubella virus, the origin of the virus prior to its introduction into the human population is unknown. Rubella virus and the alphaviruses share no nucleotide homology except for short stretches at the 5' end of the genome and at the subgenomic promoter site. Thus these two genera are only distantly related. Rubella virus and the alphaviruses both belong to the 'alphavirus-like superfamily' of plus-sense RNA viruses which includes a large number of plant viruses as well as human hepatitis E virus, which is currently classified as a calicivirus. Within this superfamily, computer-assisted phylogenetic analysis of the nonstructural

Satellite Rnas And Satellite Viruses

By helper viruses for their accumulation. However, some RNA molecules which are not required by the helper virus for experimental infection, appear to be essential for the natural life cycle of the virus, by contributing to vector transmissibility. Such examples are the RNAs associated with groundnut rosette virus (GRV) and beet necrotic yellow vein virus (BNYVV), which have been described and are referred to as satellite-like RNAs. A related group of subviral agents is that containing RNAs that resemble satellites but which depend on a helper virus only for encapsidation rather than for replication e.g. hepatitis delta virus (HDV) and beet western yellows virus (BWYV) ST9-associated RNA .

Structure and Replication

The pestivirus genome is c. 12.3 kbp, with variant genomes of larger and smaller size generated by recombination events (Figure 3). Pestivirus genomes lack a 5' cap structure, and translation is mediated by a 5' internal ribosome entry site (IRES) element that has similarities to the hepatitis C virus (HCV) IRES. The 3' UTR contains a short polyC tract, as well as variable and conserved regions, the latter of which encodes hairpin structures. The open reading frame codes for 4000 amino acids, and is processed into at least 12 mature proteins Npro, C, Erns, E1, E2, p7, NS2, NS3, NS4A, NS4B, NS5A, and NS5B. Npro is a unique N-terminal leader autoprotease, which is followed by the four structural proteins C, Erns, E1, and E2. Erns, which is not found in other viruses of the family, is a heavily glycosylated protein that is secreted from cells and exhibits a ribonuclease activity and a lymphocyto-toxic activity that is involved in pathogenesis. E1 and E2 are integral membrane proteins...

History and Classification

After serologic screening tests for the detection of hepatitis B and hepatitis A viruses were introduced in the 1970s to eliminate these viruses from human blood supplies, the role of HCVs in causing up to 90 of transfusion-associated hepatitis was recognized. The term hepatitis C virus (HCV) was coined in 1989 after identification of an RNA genome of this virus from cDNA libraries of human serum containing the infectious agent. In humans, infection with HCV commonly evolves into a chronic persistent hepatitis which can lead to progressive hepatic cirrhosis and hepatocellular carcinoma. Lack of a suitable cell culture system for propagating HCV had until only recently been a major impediment to progress in understanding the details of its replication. In addition, studies of HCV pathogenesis have been hampered by the lack of animal model systems, and progress has depended on use of clinical data from human cases, or from the use of a chimpanzee model. c. 30-35 , 20-25 , and 1-10 ,...

Epidemiology and Clinical Disease

It is estimated that there are at least 170 million chronically infected HCV subjects worldwide, with prevalence varying from 0.1 to as high as 18 (Egypt). In areas where HCV has been eliminated from blood supplies by donor screening, use of illicit injectable drugs remains the most important mode of transmission. Various other forms of exposure, including occupational and sexual exposures, are involved in some cases of transmission. HCV is a primary cause of cirrhosis, a significant cause of hepato-cellular carcinoma, and in the United States is the leading reason for liver transplantation. There is great variability in the spectrum of disease. Acceleration of disease is observed in persons who are older at the time of infection, and in the setting of continuous alcohol exposure, and co-infection with HIV or hepatitis B virus (HBV). Individuals who sustain infection at a younger age tend to have slower progression. Genotypes 1, 2, and 3 are found worldwide, but with regional...

Diagnosis and Treatment

Diagnosis of chronic hepatitis C infection is established by screening enzyme immunoassay to detect circulating antibodies to HCV proteins, followed by confirmatory determination of HCV RNA in serum, using qualitative and quantitative tests based on target (RT-PCR and transcription-mediated amplification) and signal amplification (branched DNA (bDNA)) techniques. Quantitation of serum HCV RNA helps to identify patients likely to benefit from treatment and undergo virus clearance as defined by a sustained viral response (SVR). Determination of the HCV genotype guides treatment decisions, as genotypes 1 and 4-6 are less amenable to treatment than are genotypes 2 or 3. Therapeutic trials have shown that combinations of interferons and ribavirin are more effective than is interferon alone and pegylated (long-acting) interferons have yielded improved SVR rates. An SVR is less common in patients with genotype 1 infections, high pretreatment HCV RNA levels, or advanced stages of fibrosis....

Application for Other Organisms

Pseudomonas aerugenosa. 24 Furthermore, ribotyping has been applied successfully in many studies to differentiate bacterial strains. 25,26 Other applications of locus-specific RFLP found place in epidemiological studies of hepatitis C virus (HCV). By this technique, the virus can be subtyped into six major genetical groups. 27 The RFLP of the 5' untranslated region has facilitated studies of the geographical distribution of viral genotypes and natural history of the disease.

History of Virus Classification and Virus Nomenclature

Virus classification is a relatively new exercise, as the first evidence for existence of a virus was only presented at the end of the nineteenth century by Beijerinck in 1898. It was not until 1927 that Johnson, a plant virologist, drew attention to the need for a system of virus nomenclature and classification. First efforts to classify viruses utilized a range of ecological and biological criteria, including pathogenic properties in the case of human and animal viruses, and symptoms for plant viruses. For example, viruses sharing the pathogenic properties causing hepatitis (e.g. hepatitis A virus, hepatitis B virus, yellow fever virus, and Rift Valley fever virus) were grouped together as 'the hepatitis viruses'. Virology developed substantially in the 1930s and early classifications for the viruses reflected these advances. In 1939, Holmes published a classification of plant viruses dependent on host reactions and differential host species, using a binomial-trinomial nomenclature...

Clinical manifestation

Main identifiable causes drug induced, such as angiotensin-converting enzyme inhibitors, penicillin, sulfonamides, fluoxet-ine, and thiazides rheumatic diseases, such as lupus erythematosus and Sjogren syndrome viral diseases, such as hepatitis B, hepatitis C, and infectious mononucleosis hypocomplementemia occurs in patients with associated systemic diseases, such as systemic lupus erythematosus regardless of cause, disease tends to run chronic cours

Biology of the Viruses

Figure 1 An unrooted phylogenetic tree showing the genetic relatedness between hepadnaviruses isolated from ducks, geese, herons, storks, and cranes. Reproduced from Prassolov A, Hohenberg H, Kalinina T, et al. (2003) New hepatitis B virus of cranes that has an unexpected broad host range. Journal of Virology 77 1964-1976, with permission from American Society for Microbiology.

Genetic Variation and Epidemiology

Figure 2 (a) Organization of the HBV genome. The inner circles depict the complete minus strand and incomplete plus strand and the positions of the direct repeats (DR) are indicated. The blocks surrounding the genome show the locations of the four overlapping ORFs C and S contain two and three in-frame initiation codons, respectively. (b) Organization of the DHBV genome. A simplified view illustrating the single pre-S region and lack of an XORF. (a) Reproduced from Kidd-Ljunggren K, Miyakawa Y, and Kidd AH, etal. (2002) Genetic variability in hepatitis B viruses. Journal of General Virology 83 1267-1280, with permission from Society for General Microbiology. conformational region, comprising a number of overlapping epitopes, is the main target of the humoral response, and antibodies synthesized during convalescence or in response to the hepatitis B vaccine are protective. Two pairs of mutually exclusive subdeterminants, d or y and w or r, correlate with variation (in both cases...

Clinical Features and Pathology

The clinical features of acute viral hepatitis in humans are nonspecific and are not dependent on the etiology of the infection they include fatigue, anorexia, myalgia, and malaise. Jaundice may be evident in the more severe cases, but often the infections may be anicteric (without jaundice) or even asymptomatic. In hepatitis B, these clinical features are evidence of a robust immune response to the virus and a sign that the infection will be cleared by the immune system. In a minority of cases, less than 5 of immune competent adults, asymptomatic infections persist in individuals who do not mount a vigorous immune response. Such persistent infections, originally termed the chronic carrier state, are defined formally by the persistence of HBsAg in serum for more than 6 months. Figure 5 Global prevalence of persistent HBV infection (HBsAg in serum). Reproduced from http www.cdc.gov ncidod diseases hepatitis slideset hep_b slide_9.htm, with permission from Central Food Technological...

Prevention and Treatment of Infection

HBV infection can be prevented by immunization, intramuscular administration of HBsAg leading to a protective anti-HBs response. The first vaccine (so-called plasma-derived vaccine) was produced by purifying HBsAg from the plasma of hepatitis B carriers. Second-generation vaccines contain HBsAg produced from yeast or (less commonly) mammalian cells by recombinant DNA technology. The World Health Organization recommends universal immunization of infants and this is now carried out in many countries. The key is to break the chain of transmission from infected mothers to their infants, and giving the vaccine within 24 h of birth protects 70-90 of such babies. Protective efficacy may be increased by giving passive protection with hepatitis B immune globulin (HBIG) at a contralateral site. In Taiwan, one of the first countries with a high prevalence of HBsAg to introduce universal immunization of infants, that prevalence has been reduced from more than 10 to less than 1 in the immunized...

Virion Structure and Genome Organization

The infectious virion or Dane particle measures about 42 nm in diameter and consists of an outer envelope containing hepatitis B surface proteins (HBsAg) in a lipid bilayer (Figure 2). This in turn encloses the nucleo-capsid core of the virus, within which lies the viral genome and a copy of its polymerase. Apart from virions, liver hepatocytes release into the circulation subviral particles devoid of nucleic acid and consisting entirely of HBsAg. These are the 22 nm spheres and the filamentous The precore core ORF contains two in-frame initiation codons and therefore yields two translation products. Initiation of translation from the first results in synthesis of the precore polypeptide, which forms the precursor of the soluble hepatitis B e antigen (HBeAg). This protein contains a signal peptide at its N-terminus that anchors the protein in the endoplasmic reticulum membrane. Cleavage by signal peptidase in the lumen is followed by further processing of the C-terminus. The resulting...

Structure and Replication of HBV

The 42 nm hepatitis B virion is composed of the DNA genome packaged together with a copy of the virus-encoded polymerase in an icosahedral nucleocapsid made up of dimers of the hepatitis B core antigen, HBcAg. In turn, the nucleocapsid is covered by an envelope composed of a lipid bilayer derived from internal cellular membranes and embedded with the hepatitis B surface protein, HBsAg. The open reading frame (ORF) encoding HBsAg has three in-frame initiation codons (Figure 1) which are used for the translation of the large (L, pre-S1 + pre-S2 + S), middle (M, pre-S2 + S), and small (S or major) surface proteins. All three proteins, which share the same C-terminus, are found in the virions. Figure 1 Organization of the HBV genome. The inner circles depict the complete minus strand and incomplete plus strand, and the positions of the direct repeats (DRs) are indicated. The blocks surrounding the genome show the locations of the four overlapping ORFs C and S contain two and three...

Hepatocellular Carcinoma

Primary liver cancer is among the most common fatal malignancies of humans worldwide. An association with hepatitis B virus (HBV) from the hepadnavirus family was suggested by the geographical coincidence of a high incidence of hepatocellular carcinoma in southeast Asia and equatorial Africa with high rates of chronic HBV infections, generally contracted congenitally. Prospective studies demonstrated about a hundredfold increased risk of hepatoma among carriers of the HBV surface antigen (HBsAg). Integrated HBV DNA can be detected in a large proportion of the tumors from high-risk areas and in hepatoma-derived cell lines. Liver cancer usually develops only after several decades of chronic HBV-induced hepatitis and may thus be triggered by accumulating genetic damage due to inflammation and continuous cell regeneration. A specific contribution of HBV might be expected from cis effects following integration of viral DNA, but except for a few case reports no consistent evidence has been...

Taxonomy and Geographical Distribution

HCV has been classified as the only member of the genus Hepacivirus and grouped together with the genera Pestivirus, Flavivirus, and tentatively the GB-viruses, in the family Flaviviridae. According to phylogenetic analyses, HCV is more closely related to the pestiviruses than to the flaviviruses. Based on genomic heterogeneity, six major genotypes, having more than 30 nucleotide sequence divergence, and more than 70 subtypes differing from each other by 10-30 at the nucleotide sequence level, have been defined. Subtypes are designated by lowercase letters following the number of the genotype (e.g., genotype 1 subtype b 1b). While genotype 1 and 2 viruses are prevalent almost worldwide, HCV genotypes 3-6 are to a large extent restricted to distinct geographical regions, including the Indian subcontinent and Southeast Asia (genotype 3), Africa and Middle East (genotype 4), South Africa (genotype 5), and Southeast Asia (genotype 6). Individual genotypes have not been ascribed to...

Sampling Errors Differential Enrichment and Recovery During Culture

Treponema pallidum PCR for hepatitis C virus In viral load assays conducted to predict the prognosis of patients with HIV and hepatitis C virus, the expense of commercial test kits precludes monitoring with the frequency that might be useful. The sample is a biased one, taken perhaps every 3 months and may not be helpful for showing variations in viral load in the period between samples. As quantitation is the vital aspect of viral load monitoring, factors that alter the number of virions such as delays in transport and processing may lead to errors in assessing this prognostic indicator. Similar considerations apply when sampling shellfish beds for viruses. Representative samples must be taken from the bed to allow for spatial variations, quantity of virus will be affected by the species of shellfish and its filtration rate, and transport and processing should be prompt and temperature controlled.

Virion Properties

HCV particles are enveloped and spherical and have a diameter of 55-60 nm as determined by filtration and electron microscopy (Figure 4). By analogy to other flaviviruses, HCV particles are composed of at least the genomic RNA, the core protein, and the two envelope proteins E1 and E2 which are embedded into the lipid envelope. The core protein forms the internal viral capsid (presumably 30-35 nm in diameter) that shelters the single-stranded RNA genome (Figure 4). The S20W is approximately 200S and infectious HCV virions isolated from the plasma sample of infected patients and chimpanzees have low buoyant densities in the range of 1.05-1.10gml_1.

Tissue Tropism and Host Range

Hepatocytes are considered to be the natural target cells for HCV. Viral RNA was also detected in peripheral blood mononuclear cells (PBMCs) and bone marrow cells but it is unclear whether productive infection occurs in these cells. In cell culture, HCV RNA replication was demonstrated in non-liver cells like human T- and B-cell lines or embryonic kidney cells (293). Furthermore, certain mouse cell lines can support replication of HCV replicons demonstrating that the viral replication machinery is also functional in a murine host cell environment.

Experimental Systems Animal Models

Possibilities to propagate HCV in vivo are rare. For many years HCV could be propagated only in chimpanzees after experimental inoculation with virus containing samples from patients or synthetic in vitro transcripts derived from cloned infectious genomes. More recently, transgenic mice Figure 3 HCV replication cycle. (1) HCV virion binds to one or several receptors on the surface of the cell. Glycosaminoglycans, SR-B1, CD 81, and eventually LDL receptor are required for or contribute to virus binding and entry. (2) The virus particle supposedly enters the cell via clathrin-mediated endocytosis. (3) After a low-pH-mediated fusion step from within an acidic endosome and uncoating, the HCV genome is liberated into the cytoplasm of the host cell. (4) The viral RNA genome is translated at the rough endoplasmic reticulum (rER). (5) The membranous web presumably originating from ER membranes is formed. (6) It is the site of viral RNA amplification which occurs via negative-strand RNA...

Pathogenesis and Tissue Tropism

The pathogenesis of HEV is largely unknown. It is believed that HEV enters the host through the fecal-oral route. However, the primary site of HEV replication is not known. In primates and pigs experimentally infected with human and swine HEVs, virus replication in the liver has been demonstrated. It is believed that, after replication in liver, HEV is released to the gallbladder from hepatocytes and then is excreted in feces. In pigs experimentally infected with human and swine HEVs, in addition to the liver, HEV replication was also identified in extrahepatic tissues including small intestine, colon, hepatic, and mesenteric lymph nodes. Although the clinical and pathological significance of these extrahepatic sites of virus replication is not known, it is believed that HEV may first replicate in the gastrointestinal tract after oral ingestion of the virus, and subsequently spreads to the target organ liver via viremia. It has been well documented that pregnancy increases the...

Humanmediated genetic exchange

In regard to point three, Arnold and Larson (2004) continue, 'Whether transferring delayed ripening genes from a disease of bacteria (i.e. a bacteriophage) into cantaloupe to prevent our breakfast from going mushy too quickly, or splicing a gene for pesticide resistance from bacteria into corn to keep insects from feeding on the plants in a field, or implanting the gene for human interferon into the DNA of chickens so that their eggs contain the protein used to battle hepatitis C, or introducing the gene for a red fluorescent protein from a sea anemone into zebra fish so that they look more attractive to us in an aquarium, biotech researchers now move genes between species so unrelated to

RNA Virus Vector Systems

Poliovirus, a positive-strand RNA virus, has been used to express a number of foreign genes. Poliovirus vectors expressing epitopes derived from hepatitis A virus, rhinovirus 14, human papillomavirus 16, foot-and-mouth disease virus and HIV have been produced. A poliovirus-HIV chimera has been shown to elicit anti-HIV antibodies in rabbits. Furthermore, this antiserum neutralized a wide range of American and African HIV-1 isolates. The major disadvantage of polio, relative to the negative-strand RNA virus vector systems, is that the systems that have been developed thus far have a limited capacity for foreign sequences.

Reading and Interpretation Errors

Misinterpretation of typing may occur and it is important to focus on clinical problem-solving rather than modern methods alone. Typing is not mystical. Its goal is simply to provide evidence that epidemiologically related isolates are also related genetically, represent the same strain, and thus may have a common origin. In larger-scale studies, it may also suggest that genetically related isolates have a common epidemiological source. This may be harder to prove with certainty and gives potential for falsely positive associations that could have costly implications for the agricultural and food industries if food products are mistakenly implicated by overzealous investigators. An outbreak can occur with more than one epidemic strain, and an outbreak is not excluded because of strain heterogeneity (205). Hepatitis C viral quasispecies, heterogenous mixtures of virus particles containing hypervariable regions, sequentially change during the natural course of infection and the...

Atomic Structure of Viral Proteins

There are many functional viral proteins that do not have any symmetrical quaternary structure in virus particles. Therefore, their atomic structure has to be studied by crystallizing isolated proteins. Crystal structures have been determined for the hemagglutinin (HA) and the neuraminidase (NA) of enveloped influenza virus, and the protease and reverse transcriptase of human immunodeficiency virus (HIV) and other retrovirus, matrix and capsid proteins (influenza virus and HIV SIV), a fragment of the HIV glycoprotein gp41, the protease of picorna-viruses, the protease and the thymidine kinase of herpesvirus, the protease of hepatitis C virus, the receptor binding domain of adenovirus fiber and the envelope glycoprotein of tick-borne encephalitis virus.

Diagnosing Wilson Disease A High Index Of Suspicion

Liver biopsy with determination of hepatic copper content is the most valuable single diagnostic procedure. Liver copper 250 pg g dry weight is highly suggestive for Wilson disease, but may be also found in cholestatic diseases and in idiopathic copper toxicosis. The major shortcoming of a single liver biopsy specimen is underestimation of hepatic copper because of inhomogeneous copper deposition in the liver. Detection of copper in histological specimens by special staining methods such as rhodamine or orcein staining depends on its intracel-lular localization and is therefore insensitive and rarely helpful in establishing diagnosis. The histological findings in Wilson disease may resemble the features of various other liver disorders such as autoimmune hepatitis or nonalcoholic steatohepatitis.

History and General Characteristics

In heavily infected countries or in areas where there is an uncontrollable virus spread, a systematic and strict vaccination scheme should be implemented to curtail virus circulation. Vaccination, however, precludes the use of serology for diagnostic purposes, because the antibody response after vaccination cannot be distinguished from that after infection. Consequently, it is difficult to demonstrate convincingly the absence of HCV which jeopardizes the export of pork. Marker vaccines that allow the differentiation between infected and vaccinated pigs with the use of an epitope-specific serological test will soon become available. These vaccines contain the E2 protein, produced in baculovirus, and are formulated with an adjuvant.

Natural History of the Disease

Natural History Disease Diagram

Exposure to HBV may result in asymptomatic, acute icteric, or, in some instances, fulminant hepatitis (0.1-0.5 ). Approximately 5 of adults and 95 of peri-natally infected young children become persistently infected. The outcome depends on the age of the patient and genetic factors determining the efficiency of the host immune response. Genetic factors influencing outcome (in more than one study) include polymorphisms of the MHC class II glycoproteins, which influence presentation of viral peptides during induction of the cellular immune response, and mannin-binding lectins, which bind to mannose-termi-nated carbohydrate residues such as those present on the C-terminus of the Pre-S2 region of the middle envelope protein facilitating phagocytosis. The risk of chronicity in children decreases with increasing age. A small proportion of carriers each year may become HBsAg negative (0.05-2 , depending on age of infection), thus leading to resolution of the hepatitis. The incubation period...

Monitoring Gene Delivery

Cursive Tattoo Fonts

Gene delivery for gene therapy of a variety of human and also for animal diseases e.g. cystic fibrosis 1 , hepatitis 2 , haemophilia 3 , cancer 4-6 , and more speculatively mitochondrial gene therapy for respiratory chain defects, i.e. defects that involve the final common pathway of oxidative metabolism 7 , can be performed with either a viral 8-10 or a non-viral vector 11-14 . Lipopolyamines (cationic lipids) recently developed for non-viral gene therapy show significantly lower toxicity than viral vectors, although they are currently less efficient transfection vectors than viruses 11-14 , The poor efficiency of DNA delivery to the nucleus, especially using non-viral vectors, is a major limitation of the gene therapy approach. A poor understanding of the molecular mechanisms of action in non-viral gene delivery 11, 15 , and a lack of correlation between in vivo and in vitro biological activity 16-18 are unresolved issues and constitute the main current challenges. Whilst true gene...

Assay Formats Direct Hybridization

Oligonucleotide Ligation Assay Principle

In addition to expression profiling, sequence-specific hybridization of labeled PCR product to microspheres has been performed. A sensitive multiplexed bead assay for the detection of three viral nucleic acids (HIV, HSV, and HCV) was developed. Here labeled primers were used in the amplification of the relevant viral nucleic acids, which were hybridized to sequence-specific oligonucleotides bound to the beads. 5

Frequency and timing of antenatal visits

Pregnancy such as diet, smoking, folic acid supplementation etc. A crucial aim is to identify those women who will require additional care in the pregnancy (Table 6.1). A urine test should be sent for bacteriological screen and a booking for ultrasound arranged. Sufficient time should be set aside for an impartial discussion of the screening tests available including those for anaemia, red-cell antibodies, syphilis, HIV hepatitis and rubella. Because of the complexity of Down's syndrome, this too should be discussed in detail and supplemented with written information. Ideally another follow-up appointment should be arranged before the screening tests need to be performed to allow further questions and arrange a time for the tests following maternal consent.

Posterior Lv Wall Motion Is Dyskinetic Reasons

Coronary Arteries Territories Echo

Pseudo-dyskinesis in 54-yr-old male with end-stage liver disease. Left ventricular walls in this 54-yr-old male with end-stage cirrhosis owing to chronic alcohol use and hepatitis C virus infection was normal during diastole (A-C). Apparent hypokinesis dyskinesis in the postero-inferior walls (B,D, arrows) was a result of external pressure from tense ascites secondary to his end-stage liver disease. (Please see companion DVD for corresponding video.)

Complementary therapies

A recent small randomized controlled trial of 45 post-menopausal women undergoing shallow acupuncture, electro-acupuncture or oral oestrogen administration showed a significant reduction in hot flush frequency in all three groups. The degree of symptom reduction was greatest in the oestrogen group 56 . Although no adverse effects were demonstrated in this study, rare adverse effects such as cardiac tamponade, pneumothorax and hepatitis have been described. Further data are required to establish the precise benefits of acupuncture for the menopause.

Radiology investigations

Where there is difficulty, but is also not widely available and certainly has not yet entered routine management. Computerized tomography (CT) scanning in acute PID may show obscuring of the pelvic fascial planes, thickening of the uterosacral ligaments and accumulation of fluid in the tubes and endometrial canal. In the upper abdomen it can provide evidence of peri-hepatitis. Enhancement of the hepatic and splenic capsules on abdominal CT scan has been suggested as characteristic of the Fitz-Hugh-Curtis syndrome but is of little value as a routine investigation.

Plants as Bioreactors

Molecular biotechnology will enable broadening of the range of products and use of transgenic plants as a versatile renewable and low-cost source of novel high-value molecules (Goddijn and Pen, 1995 Arakawa et al., 1999 Dunwell 1999 Fischer et al., 1999 Fischer and Emans, 2000 Giddings et al., 2000). This area of novel commercial exploitation of plants is called biofarming or molecular farming and involves the crop-plant-based production of industrial or therapeutic biomolecules. In this application, the plant can be considered as a solar-powered bioreactor and an attractive alternative to conventional microbial or animal cell expression systems. Its requirements are simple and inexpensive sunlight, mineral salts from the soil (or fertilizers), and water (Goddijn and Pen, 1995 Arakawa et al., 1999 Dunwell 1999 Fischer et al., 1999 Fischer and Emans, 2000 Giddings et al., 2000). Similarly, as traditional agriculture takes advantage of these characteristics in the large-scale production...

The Surface Protein HBsAg

Are believed to be linked by disulfide bridges, forming a complex structure that includes the a determinant and d y and w r subdeterminants. Antibody (anti-HBs) responses to this domain give immunity to infection in convalescence or following immunization with hepatitis B vaccine. Approximately half of the S residues are N-glycosylated at aa 146 (in the a determinant) so that the protein exists in two forms, p24 and gp27. Figure 4 (a) Predicted structure of the major surface protein, S. Note the abundance of cysteine residues in the major hydrophilic region. (b) Dual topology of the large surface protein, L. (a) Reproduced from Stirk HJ, Thornton JM, and Howard CR (1992) A topological model for hepatitis B surface antigen. Intervirology 33 148-158, with permission from Karger Publishers. (b) Reproduced from Lambert C, Mann S, and Prange R (2004) Assessment of determinants affecting the dual topology of hepadnaviral large envelope proteins. Journal of General Virology 85 1221-1225,...

Defining the Correlates of Protection

A second group of individuals who have attracted intense scrutiny are the long-term nonprogressors (LTNPs), who maintain high CD4 T-cell counts and low-to-undetectable viral loads for many years after HIV-1 infection. Again, these people are not a homogeneous group but consist of those of certain HLA types groups co-infected with hepatitis G (GB virus C) cohorts who have poly-functional CTL responses, capable of lytic function as well as releasing antiviral cytokines, b-chemokines, and or CD8 antiviral factor (CAF), which suppresses HIV-1 replication at the level of transcription those possessing TCR clones capable oftolerating mutation in the target epitope a few individuals infected with naturally attenuated viruses that are mutated in regions such as nef and vpr, and rare individuals who have broad nAb responses.

Viruses that Promote Apoptosis DNA viruses

Hepadnaviridae Hepatitis B virus (HBV)-infected cells undergo apoptosis, contributing to fulminant hepatitis. Expression of FAS is upregulated and correlates with viral hepatitis, but not directly with HBsAg expression. Some data suggest that it is due to the viral pX gene product, a multifunctional regulatory protein. pX has also been shown to prevent apoptosis and contribute to hepatocarcinoma development. Coronaviridae Infections with mouse hepatitis virus result in transient atrophy of the thymus. CD4+ and CD8+ lymphocytes are depleted and apoptosis of lymphocytes increases. The viral A59 (MHV-A59) gene is responsible, but its function or mechanism is presently not known. Flavivirus The hepatitis C virus (HCV) core protein activates the FAS-mediated cell death pathway, by upregulating FAS. It can be prevented by inhibiting the CPP32 cysteine protease, but not ICE. Thus, the CPP32 protease is involved in the apoptosis effector pathway of HCV and may contribute to HCV...

Peach latent mosaic viroid

Peach Latent Mosaic

Figure 2 Consensus phylogenetic tree containing 22 viroids, viroid-like satellite RNAs and the viroid-like domain of hepatitis delta virus RNA. ASBVd has been taken as outgroup. ***, Group monophyletlc in all 1000 bootstrap replicates monophyletic in more than 99 in more than 95 +, in more than 90 and - , in more than 80 of all replicates. From ASBVd to the left of the figure groups are considered as being within the viroid family, and from ASBVd to the right (including the viroid-like domain of HDV RNA) as within the satellite family. For example, satellite tobacco ringspot virus (sTRSV) and satellite Arabis mosaic virus (sArMV) (satellite family) or CCCVd, CTiVd and HLVd (viroid family) conformed to two well-defined monophyletic groups in all bootstrap replicates. G1 BVd, grapevine viroid 1B LTSV, Lucerne transient streak virus ScMoV, subterranean clover mottle virus SNMV, Solanum nodiflorum mosaic virus VTMoV, velvet tobacco mottle virus. Other abbreviations as in Table 1. (From...

Viruses Affecting the Heart

Commonly e.g. enteroviruses, human immunodeficiency virus (HIV) and, if acquired congenitally, rubella whereas others are uncommon e.g. varicel-la-zoster, cytomegalovirus (CMV) and hepatitis B . Many of these viruses involve the heart as part of a clinically obvious generalized infection (e.g. varicella, mumps and rabies) whereas in others, cardiac disease is the primary presenting clinical feature. The more common causes of viral heart disease are discussed below, but some of those occurring less commonly are listed in Table 1.

Properties of the Genome

All members of the Hepadnaviridae family have a partially double-stranded DNA genome of about 3 kb that is held in a circular conformation by a short cohesive overlap between the 5' ends of the two DNA strands (Fig. 1). One strand is always complete in virus particles, whereas the second strand is incomplete, with a 3' end that is heterogeneous in location. The incomplete strand is of plus polarity and the complete strand of negative polarity. When these viruses infect a cell, the plus strand is completed and the fully double-stranded DNA is then converted to a covalently-closed circular (CCC) molecule, which serves as a template for viral RNA synthesis (Fig. 2). The two genera of hepadnaviruses are thought to differ in that orthohepadnaviruses encode four open reading frames (ORFs) whereas the prototypic avihepadnavirus, duck hepatitis B virus, encodes only three, lacking the X ORF. This ORF appears to encode a protein that modulates transcription, possibly by acting on signal...

Differential Regulation of Key Signaling Molecules in Innate Immunity and Human Diseases

Egg Sinker Leader Combo

That have various N-terminal deletions. Upon overexpression, IRAK-2a and IRAK-2b could activate, while IRAK-2c and IRAK-2d inhibit NFkB activation. Alternative splicing of the IRAK-2 gene in mice instead of humans reflects the difference between human and murine TLR signaling processes and innate immunity regulations. The physiological function of IRAK-2 is poorly defined. Intriguingly, it was reported that several cases of human liver tumors harbor Hepatitis B Virus (HBV) DNA insertion near the IRAK-2 gene, which implies that IRAK-2 and related cellular signaling pathways may regulate human carcinogenesis (Paterlini-Brechot, Saigo, Murakami, Chami, Gozuacik, Mugnier, Lagorce and Brechot 2003). Further studies are needed to determine the biochemical regulation of IRAK-2 and its participation in various cellular signaling pathways.

The Cognate Immune Response

It has been shown that ob ob mice are completely resistant to a concanavalin A (Con A)-induced T-cell-mediated hepatitis. This resistance was abrogated by exogenous leptin replacement (112). It was also demonstrated that equally obese mice that had had their endogenous leptin levels raised by a hypothalamic lesion induced by an injection of gold thioglucose had worse hepatitis that lean wildtype mice (116). This would suggest that the key cytokine in this T-cell-dependent model was leptin. Similar findings have been reported in a Th1-dependent model of colitis, which shows elevated leptin levels during the induction of colitis that correlate with the severity of the colonic inflammation (117). Interestingly, human studies have reported that serum leptin levels do not necessarily correlate with the severity or the presence of colitis. This is entirely consistent with the animal model, whereby at later stages of the disease, leptin levels are not particularly raised. The ob ob mice are...

AID regulation and cancer correlation

EBV, HCV, Abl-MLV, H. pylori, estrogen Hepatitis C virus (HCV) is able to infect hepatocytes as well as B cells and causes hepatocellular carcinoma and non-Hodgkin's B cell lymphoma (Weinberg, 2007). Infection promotes AID expression in B cells isolated from peripheral blood, and analogous to EBV infection, induces error-prone polymerases (Machida et al., 2004), with mutations driven by AID identified in the IgH locus, BCL6, p53 and -catenin genes. Furthermore, AID expression has also been detected in hepatocytes after HCV infection (Kou et al., 2007). Although some of the above pathways are listed as independent control mechanisms for AID expression, there are of course numerous instances where the combination of two or more pathways can contribute to AID's oncogenic potential. Examples of these are the interaction of the NFkB and estrogen transcription pathway (de Bosscher et al., 2006 Stice and Knowlton, 2008), the SP1 transcription factor and hormone pathway (Solomon et al.,...

Idiopathic hypersomnia

True idiopathic hypersomnia is believed to be less common than narcolepsy, but estimating prevalence is difficult because there had been no strict diagnostic criteria and there continue to be no specific biological markers. The first symptoms tend to occur in late adolescence or early adulthood. No cause for idio-pathic hypersomnia has been clearly identified, but viral illnesses, including those that may lead to Guillain-Barre syndrome, hepatitis, mononucleosis, and atypical viral pneumonia, may be related to the onset of EDS in a subset of patients 27 . EDS may occur as part of the acute illness but persist after the other symptoms subside. HLA-Cw2 and HLA-DR11 have been noted to occur with increased frequency in some rare familial cases 38 .

Screening for maternal complications

Maternal blood should be taken early in pregnancy and with consent screened for hepatitis B, HIV, rubella and syphilis. Identification of women who are hepatitis B carriers can lead to a 95 reduction in mother to infant transmission following postnatal administration of vaccine and immunoglobulin to the baby. Women who are HIV positive can be offered treatment with antiretroviral drugs which, when combined with delivery by Caesarean section and avoidance of breast feeding, can reduce the maternal transmission rates from approximately 25 to 1 4 . Such women need to be managed by appropriate specialist teams. Rubella screening aims to detect those women who are susceptible to the virus allowing postnatal vaccination to protect future pregnancies. All women who are rubella non-immune must be counselled to avoid contact with any infected person and if inadvertently she does, she must report the event to her midwife or doctor. Serial antibody levels will determine whether infection has...