Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0019163 (hepatitis B)
 38,309 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A dot hybridisation technique was used to monitor the levels of hepatitis B virus (HBV) DNA in the plasma of two HBV-carrier chimpanzees which had been inocula ed with documented infectious non-A, non-B hepatitis agents. A marked decrease in the quantity of HBV DNA in the plasma during the acute phase of the non-A, non-B hepatitis was observed in both carriers. The possible role of interferon or a similar antiviral agent in modulation of the HBV-carrier state is discussed. Hybridisation may become, in due course, the method of choice for examining blood samples for infectious hepatitis B virus.
 ...
PMID:Assay of HBV DNA in the plasma of HBV-carrier chimpanzees superinfected with non-A, non-B hepatitis. 640 16

Viral hepatitis is a major public health problem, occurring endemically in all areas of the world. The prevalence of the disease is influenced by numerous factors which may be able to modulate its onset. Study of the epidemiology of viral hepatitis in different geographical, ethnic, social and genetic groups as well as immunological and individual factors has contributed much to our understanding of the disease. Hepatitis viruses are classified into A (infectious hepatitis), B (serum hepatitis) and non-A, non-B. The transmission of hepatitis B virus (HBV) is a potential hazard in dental practice. A number of reports suggest a significantly higher incidence of hepatitis among dentists than in the general population and also higher rates of hepatitis in certain specialists, especially oral surgeons, periodontists and endodontists, than in general dentists. Vectors of infection with HBV in dental practice are blood, saliva and nasopharyngeal secretions. The incidence of hepatitis B in dental practitioners is influenced by the exposure to infection, the type of practice, the number of years of professional experience and antibody response. HBV may be spread by dentists and dental students, by dental auxiliaries and by other personnel closely associated with clinical practice, who are antigen positive carriers but have no clinical symptoms. Therefore, dentists and their staff should know well the risk of infection from their patients, the risk of cross-infection between patients, and the risk of infecting each other.
 ...
PMID:Status of viral hepatitis in the world community: its incidence among dentists and other dental personnel. 658 34

Since 1982 two hepatitis B (HB) vaccines have been commercialized. Both contain mainly non-infectious hepatitis B surface antigen particles and are manufactured from purified and inactivated plasma of healthy HBs-antigen carriers. H-B- Vax (Merck, Sharp & Dohme) is administered intramuscularly in two 20 micrograms doses one month apart, followed by a booster injection six months after the initial dose. Hevac B Pasteur is injected subcutaneously in three 5 micrograms doses at monthly intervals, with a booster dose 12 months after the first. Side effects are mild and not significantly more frequent than after placebo. Both vaccines are effective, as shown by the appearance of antibodies against HBs antigen in over 95% of healthy vaccines. HB infection occurred only in the first months after vaccination and in people with insufficient antibody response. Patients with compromised immune reactivity, such as those with endstage renal failure or with a transplanted organ, develop anti-HBs less often and also in lower titers than healthy individuals. In Western Europe and in the United States HB vaccination should be restricted to persons at high risk such as medical and dental personnel, patients with endstage renal failure, i.v. drug users, male homosexuals, close contacts of HBs carriers, refugees from countries with high HB endemicity and travellers to such countries. In developing countries with very high prevalence of hepatitis B, extensive programmes of vaccination in infants should be initiated. Serotesting before vaccination is only useful in people with an exposed probability of positive HBV markers well over 10%. Serotesting after vaccination should be done in health care personnel where non-responders can be protected with intermittent injections of HB immunoglobulin. In selected cases combined passive-active immunization may be useful.
 ...
PMID:[Hepatitis B vaccination]. 672 15

Hepatitis B viral (HBV) DNA was detected in a hepatoma cell line which produces hepatitis B surface antigen (HBsAg) and in patients with acute hepatitis B. The serum of one patient with acute hepatitis B was found to be infectious when injected i.v. into a chimpanzee up to a dilution of 10(-8). Hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg) were detectable in the same serum sample by radioimmunoassay up to a dilution of 10(-5) and of 10(-3), respectively. Using DNA: DNA hybridization on nitrocellulose membranes, HBV DNA sequences were detectable up to 10(-8) dilution corresponding to the infectivity level. Based on this finding, it appears that DNA: DNA hybridization is the most sensitive method for detecting hepatitis B virus (HBV) infection. In situations with low virus levels it may be the only indicator of the presence of infectious hepatitis B virus. The use of a tritium-labelled probe makes the method economical and adaptable to hospital laboratories.
 ...
PMID:DNA: DNA hybridization method for the diagnosis of hepatitis B infection. 674 40

Starting with 41.5 l of plasma from anti-HBe positive carriers of HBs antigen, 11,400 doses of a hepatitis B vaccine with 42 micrograms HBsAg-protein and 11,300 national units HBsAg activity per dose were obtained. After purification, HBsAg is obtained in 99% purity with a yield of more than 90% protein. A possible residual infectivity was inactivated by a diluted formalin solution. The infectivity test in chimpanzees confirmed the absence of infectious hepatitis viruses (HBV and nonA-nonB). In guinea pigs the immunogenicity of the vaccine was comparable to that of the reference preparation from the U.S. National Institute of Health. The presence of Al(OH)3 in the vaccine increased the anti-HBs titre by factors of 30-50. After vaccination with two doses 41 of 45 persons became anti-HBs positive, with three doses 42 of 45 persons developed anti-HBs. Median anti-HBs titre after the third doses: schedule I (three doses in intervals of 6 weeks) 427 mWHO-U/ml; schedule II (two doses at an interval of 4 weeks, third doses 4 months after the first doses) 1535 mWHO-U/ml. The vaccine was well tolerated. There were minor local reactions only.
 ...
PMID:[Preparation and testing of a hepatitis B vaccine (author's transl)]. 705 65

The prevalence of hepatitis A virus antibodies was tested by radioimmunoassay in Norway in healthy blood donors, in patients without clinical signs of liver diseases and in two selected groups of patients. The presence of hepatitis A antibodies was highly age-dependent in 625 normal persons. A major reduction occurred from 50 per cent or more in those born before 1938 to 10 per cent or less among those born after 1943. The decline of hepatitis A antibody prevalence was correlated to the history of infectious hepatitis epidemics in the entire country during World War II. The prevalence was not different from controls in a group of patients with various liver disorders. Hepatitis A antibodies were more prevalent in males than in females in blood donors, patients with chronic liver disorders and their controls. Hepatitis A antibodies were frequently present in prison inmates; their presence was associated with the presence of antibodies against hepatitis B virus and with anamnestic data on drug addiction.
 ...
PMID:Prevalence of hepatitis A antibodies in a normal population and some selected groups of patients in Norway. 705 77

One hundred milliliters of an inactivated hepatitis B vaccine (20 microgram/ml) were inoculated intravenously into two colony-born infant chimpanzees. Immediately thereafter each received hepatitis B virus from a documented infectious inoculum intravenously at a separate site. Neither chimpanzee developed elevation of aminotransferase levels, hepatitis B surface antigen (HBsAg), or antibody to hepatitis B core antigen during six months of evaluation, the duration of the currently recommended safety test. Both chimpanzees developed antibody to HBsAg beginning 8 and 9 weeks, respectively, after inoculation. The administration of a large intravenous quantity of vaccine antigen thus appeared capable of masking or preventing infection by simultaneously administered hepatitis B virus. This study suggests that a chimpanzee safety test for hepatitis B vaccine should not employ large quantities of vaccine antigen, since such a safety test may fail to detect small amounts of residual infectious hepatitis B virus.
 ...
PMID:Failure to detect infectious hepatitis B virus using high dose safety test for hepatitis B vaccine. 724 Oct 95

To establish the mechanism of progression to chronicity of the HBsAg-associated delta infection, serum hepatitis B virus and delta markers were tested in five babies born to HBsAg-positive mothers with anti-delta, in 42 follow-up patients with acute hepatitis B virus and delta hepatitis, and in collections of sera from 8 HBsAg carriers with anti-delta. Evidence of delta infection was found in the baby born to a mother with serum HBeAg and in none of the four babies born to mothers with anti-HBe. Hepatitis was self-limited in the 42 patients acutely infected by hepatitis B virus and delta agent; none developed persistent HBs-antigenemia and the majority displayed transient anti-delta of IgM class. In seven HBsAg carriers high titers of anti-delta developed during the follow-up; coincident with the rise of the antibody, aminotransferase elevation occurred in five previously asymptomatic carriers and persisted in three of them. No sign of infectious hepatitis B virus replication was detected in five of the carriers throughout the follow-up, and all of them had anti-HBe before the rise of anti-delta and of aminotransferase. HBsAg carriers with diminished hepatitis B virus synthesis appear to be at high risk of developing chronic delta infection and disease when exposed to the delta-infectious serum of other carriers.
 ...
PMID:Infection with the delta agent in chronic HBsAg carriers. 728 94

The PLC/PRF/5 human hepatoma cell line producing hepatitis B surface antigen (HBsAg) was studied to determine whether infectious hepatitis B virus (HBV) was also being produced. 2 chimpanzees with no previous exposure to HBV and no serologic markers of past or active HBV infection were inoculated intravenously with 50 ml of either tissue culture supernatant fluid (357 ng/ml HBsAg) or a suspension of cells disrupted by repeated freeze-thaw cycles (57 ng/ml HBsAg). No evidence of HBV infection was detected in either chimpanzee during 6 months of evaluation. This study suggests that the expression of a portion of the HBV genome, when a portion or all of that genome has been incorporated into a host cell, can result in the production of HBsAg without infectious HBV. If it becomes possible to produce a similar expression of this portion of the genome by itself in nonmalignant cells, HBsAg without HBV may be produced in vitro for use in hepatitis B vaccines.
 ...
PMID:Nondetection of infectious hepatitis B virus in a human hepatoma cell line producing hepatitis B surface antigen. 729

The effect of cold sterilization by beta-propiolactone (beta-PL) and ultraviolet (UV) irradiation of serum contaminated with infectious hepatitis B virus (HBV) was investigated in chimpanzee. Chimpanzees given 0.1 ml/kg of the undiluted HBV serum estimated to contain 10(7)-10(8) CID50/ml developed acute hepatitis B infection 4 weeks after inoculation. Chimpanzees injected with the same undiluted hepatitis serum treated with beta-PL/UV developed hepatitis B infection 14 weeks later. Based on the published linear relationship between log dose of HBV and incubation period in chimpanzees this indicates a 10(6)-fold reduction in infectivity titer. Animals inoculated with the serum diluted 1:1,000 showed manifest hepatitis B infection 11 weeks later. Animals inoculated with serum diluted 1:1,000 and then cold sterilized with beta-PL/UV showed no signs of hepatitis B infection. Sensitive proteins are not denatured by beta-PL/UV cold sterilization.
 ...
PMID:Effect of combined treatment of serum containing hepatitis B virus with beta-propiolactone and ultraviolet irradiation. 733 Dec 86


<< Previous 1 2 3 4 5 6 Next >>