Liver viral infections

Vaccination against hepatitis A and B is recommended in patients with underlying cirrhosis to prevent additional liver damage from an acute viral infection.35 Pneumococcal and influenza vaccination may also be appropriate and can reduce hospitalizations due to influenza or pneumonia. 

Reye s syndrome A sudden, sometimes fatal, syndrome characterized by encephalopathy and liver degeneration it occurs in children after viral infection and may be associated with aspirin use. 

Chronic exposure to arsenicals by way of the air, diet, and other routes has been associated with liver, kidney, and heart damage, hearing loss, brain-wave abnormalities, and impaired resistance to viral infections. 

The aminotransferases, aspartate transaminase and alanine transaminase, are enzymes that have increased concentrations in plasma following hepatocellular injury. The highest concentrations are seen in acute viral infections, or ischemic or toxic liver injury. 

Bcl-2 B cell lymphoma protein 2 (Bcl-2) is a family of proteins that regulate apoptosis (programmed cell death). Apoptosis is a necessary process whereby aged or damaged cells are replaced by new cells. Dysfunction of the apoptosis process results in disease inhibition of apoptosis results in cancer, autoimmune disorder, and viral infection, whereas increased apoptosis gives rise to neurodegenerative disorders, myelodysplastic syndromes, ischemic injury, and toxin-induced liver disease. 

The toxicity of ammonia was dramatically demonstrated by experiments carried out as early as 1931 injection of the enzyme urease, which catalyses the conversion of urea to ammonia, into rabbits rapidly caused their death. The normal concentration of ammonia in blood is about 0.02 mmol/L toxicity becomes apparent at a concentration of abont 0.2 mmol/L or above (see Table 10.1). Ammonia toxicity in very young children is usually associated with vomiting and eventually coma. It is almost invariably due to the deficiency of an enzyme of the urea cycle (see below). In adults, ammonia accnmulation, and hence toxicity, usually results from damage to the liver caused by poisons, alcohol or viral infection. 

Tinea pedis is a fungal infection commonly known as athlete s foot. Chickenpox is a childhood infection caused by the herpes zoster virus. Hepatitis is a viral infection of the liver. Mumps is a viral infection characterised by bilateral or unilateral inflammation of the salivary glands. Rubella (German measles) is caused by the rubella virus. 

Microscopic investigation of the mice from group I revealed the presence of vessel congestion, small numerous intralobular and perivenular infiltrates, moderate focal protein-hydropic degeneration combined with polymorphism of hepatocyte nuclei and inconstant lymphoid infiltration of portal tracts. Marked activation of histiomacrophage elements — hepatic macrophages must be emphasized. Homotypic moderate inflammatory alterations remained in the liver on Days 3, 5, 7 and 10. The presence of inflammatory mononuclear infiltration in the walls of central veins, typical for a viral infection, reflects a massive lesion of the vascular... 

Thus, influenza virus A/PR/8/34(HlNl) is present in the liver of infected mice of both groups and is eliminated by the end of experiment. Infected animals demonstrate persistent changes in the liver which can be estimated as viral hepatitis manifestations. In spite of influenza virus... 

Adverse events should be tabulated for easy inspection but the case report form should be available and all laboratory data such as blood coimts, renal function and liver function tests should be inspected closely The absence of obvious adverse events does not mean that all is well, and careful scrutiny of data by an experienced physician can often spot problems before they become troublesome. Not infrequently one or more volunteers become imwell during the course of a study, usually due to intercurrent viral infections, and decisions about postponement of study days and subject withdrawal follow-up can be made during these meetings. Data that are missing because of non-attendance of volunteers, for whatever reason, may lead to a delay in the study, with postponement of dose escalation imtil they have caught up. 

Hepatitis. Inflammation of the liver, usually from the viral infection, sometimes from toxic agents. 

Fulminant liver failure results from massive necrosis of liver tissue. Diminution of mental function results, and this often leads to coma. The body undergoes a buildup of toxic products, alteration of its acid balance, and a decrease in cerebral blood flow. Impaired blood coagulation and intestinal bleeding occur as well. Other malfunctions and diseases of the liver include viral infections and alcoholic hepatitis. In 1999, of the 14,707 individuals on a waiting list for transplants, 4,498 received transplants and 1,709 died while waiting. As of February 2002, 18,434 people awaited liver transplants. 

Other malfunctions and diseases of the liver include viral infections and alcoholic hepatitis. In 1999, of the 14,707 individuals who were on the waiting list for liver transplants, 4,498 received transplants and 1,709 died. As of February 2002,18,434 people awaited liver transplants. 

Hepatitis is an inflammation of the liver and is usually viral in origin however, certain chemicals, usually drugs, can induce a hepatitis that closely resembles that produced by viral infections (Table 14.1). This type of liver injury is not usually demonstrable in laboratory animals and is often manifest only in susceptible individuals. Fortunately, the incidence of this type of disease is very low. 

Infectious liver diseases are caused by infiltration of viruses, bacteria, or parasites into liver cells. The most common chronic viral infections are caused by the hepatitis B (HBV) and hepatitis C virus (HCV). These viruses all have a specific... 

Isolated human lymphocytes are used to investigate the role of these cells in the pathogenesis of various diseases and in the autologous adoptive immunotherapy for patients with malignant disease or viral infections [39,40], Lymphocytes may be used also as biomarkers of target-organ susceptibility or as a marker of chemical effects and in the prediction of individual drug sensitivity alternatively to human liver biopsies [41, 42]. 

Indinavir sulfate is a protease inhibitor and is used in combinations for the treatment of viral infection. During the high risk of HIV infection, indinavir is combined with zidovudine and lamivudine.65 Indinavir sulfate should be used with caution in patients with hepatic impairment and avoided in patients with severe liver damage. Caution is needed in diabetic patients and in patients with hemophilia. Adverse effects of indinavir sulfate include nausea, vomiting, diarrhea, fatigue, dizziness, headache, skin rashes, and allergic reactions (hematuria). 

C-reactive protein (CRP) is a protein produced by the liver during episodes of acute inflammation. CRP is not a specific test, however, and a positive CRP may indicate a number of things including inflammatory disease, malignancy, muscle necrosis (e.g. myocardial infarction) and trauma, as well as infection. A normal CRP is unlikely in the presence of a bacterial infection and a very high CRP (>100 mg/L) is more likely to occur in bacterial than viral infection. In this case, the patient s high CRP is consistent with a bacterial infection. CRP may be used to monitor a patient s response to therapy. 

Figure 16.7. Microscopic appearance of necrosis. (A) Coagulative necrosis in a virally infected avian liver. Hepatocytes in the lower half of the photo are in various stages of necrosis, with small, pyknotic or fragmented nuclei and increased cytoplasmic eosinophilia. (B) Necrotic cells in immune-mediated skin disease, canine. The central cell has a pyknotic nucleus and intensely eosinophilic cytoplasm, while the cells at lower left and upper left are injured and swollen. The smaller cells are neutrophils. See color insert.

Biomarkers can also be used to identify factors that increase the likelihood that an individual will develop disease. This is an important area of research in molecular epidemiology as it becomes more evident that not all risk factors will contribute to disease equally across the human population. Therefore, in order to determine whether an environmental agent is related to disease, those factors that are also required for disease development need to be taken into account. Otherwise, many disease risk factors may go undetected. Examples of susceptibility factors that can be ascertained using biomarkers are some viral infections, which may predispose to specific diseases (for example, HIV infection and Kaposi sarcoma) or HBV infection and liver cancer. Biomarkers can also be used to measure dietary factors that can contribute to disease. The most common susceptibility factor studied using a molecular epidemiological approach are hereditary factors, which are discussed in the following section. 

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