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Biomedical subjects

L F Barker

Publications and source records attributed to L F Barker.

At least 55 records · Page 3Linked to original sources

Hepatitis B virus infection and primary hepatocellular carcinoma.

Ninety-three patients with biopsy-proven primary hepatocellular carcinoma (PHC) from Uganda, Zambia, and the United States were examined for serologic evidence of hepatitis B virus (HBV) infection. Patients were tested for hepatitis B surface antigen (HBsAg) and its antibody (anti-HBs), antibody to the hepatitis B core antigen (anti-HBc), hepatitis B e antigen (HBeAg), and its antibody (anti-HBe). Active HBV infection, as indicated by positive tests for HBsAg (with or without anti-HBs) and anti-HBc (without anti-HBs), was present in 62% of PHC patients (58 of 93), in contrast with 10% of African controls (9 of 90), and less than 1% of most United States adult populations reported in the literature. The presence of HBeAg or anti-HBe was rare among PHC patients and controls.

Adolescent↗

Transmission of non-A, non-B hepatitis.

In studies conducted in the early 1950s, sera from six asymptomatic blood donors, implicated in the transmission of viral hepatitis, were inoculated into 10 to 20 volunteers each. Five of these "implicated" donor sera transmitted clinically apparent hepatitis to the recipients. The stored serum samples from these studies have been reanalyzed using serologic markers for hepatitis B virus and hepatitis A virus infection. Two of the donor sera were hepatitis B surface antigen (HBsAg)-positive, and both transmitted hepatitis B virus infection to all susceptible recipients, half of whom showing clinical symptoms. The remaining three infectious donors were HBs-Ag-negative, yet were icterogenic to 10% to 47% of recipients. Testing of serum samples from these recipients with hepatitis showed no evidence of hepatitis B virus or hepatitis A virus infection. This study and other recent evidence suggest that there is a third type of human viral hepatitis--non-A, non-B hepatitis--which is due to a transmissible agent and may well be associated with a chronic carrier state.

Adult↗

Subtyping of hepatitis B surface antigen and antibody by radioimmunoassay.

The hepatitis B surface antigen (HBSAg) has been shown to possess distinct subtypes adw, ayw, adr, and ayr). A commercially available solid phase radioimmunoassay for antibody to HBSAg (Ausab, Abbott Laboratories North Chicago, Ill.) has been modified to detect the subtypes of HBSAg as well as the subtype-specific anti-HBS reactivities to detect the subtypes of HBSAg as well as the subtype-specific anti-HBS reactivities (anti-d, anti-y, and anti-w). This method has the advantages of general availability, ease of performance, and increased sensitivity over conventional subtyping methods of agar gel diffusion and counterelectrophoresis.

Agar↗

Coincident hepatitis B surface antigen and antibodies of different subtypes in human serum.

Three patients with simultaneously detectable hepatitis B surface antigen (HBsAg) and antibody (anti-HBs) in their sera were studied for subtypes of HBsAg and anti-HBs. In each case anti-HBs was found to be directed to a different subtype than that of the circulating HBsAg, indicating that reinfection (or simultaneous infection) with a second subtype occurred.

Antibodies, Viral↗

Hepatitis B surface antigen and e antigen in pleural effusion: a case report.

Hepatitis B e antigen (HBeAg) and hepatitis B surface antigen (HBsAg) were demonstrated in pleural fluid obtained from a 40-year-old dialysis patient who had HBSAg and HBeAg in her serum. The titers of HBsAg and HBeAg were similar in serum and pleural fluid. Examination of the pleural fluid by electron microscopy revealed the presence of intact hepatitis B virus particles. These findings underline the potential hepatitis B virus infectivity of other body fluids besides blood, especially for medical and laboratory personnel.

Adult↗

Hepatitis B virus infection in the Wiskott-Aldrich syndrome.

Testing of paired serum samples of 12 children with the Wiskott-Aldrich syndrome for the presence of hepatitis B surface antigen (HBsAg) antibody to HB, Ag, and antibody to the hepatitis B core antigen revealed evidence of hepatitis B virus infection in three. None of the three, however, developed overt clinical hepatitis or the chronic HBsAg carrier state. These data suggest that the immunologic defects seen in the Wiskott-Aldrich syndrome permit adequate immune responses to the hepatitis B virus and do not predispose to the chronic HBsAg carrier state.

Antibodies, Viral↗

Hepatitis A antigen particles in liver, bile, and stool of chimpanzees.

Virus-like hepatitis A antigen (HA Ag) particles, presumably hepatitis A virus, were isolated from the liver, bile, and stool of three chimpanzees that had been infected with stool filtrates containing HA Ag particles. Specimens of serum, stool, liver biopsy material, and bile were obtained at selected intervals during the experiment. The animals developed mild hepatitis 19-21 days after inoculation, and antibody to HA Ag appeared de novo in their convalescent-phase serum. During acute illness, virus-like particles similar to the HA Ag particle were seen in liver cell cytoplasm by electron microscopy. HA Ag particles were detected by immune electron microscopy and a new radioimmunoassay in isopycnically banded samples of liver, bile, and stool. HA Ag particles were found at densities of 1.29-1.39 g/cm3, but the major peak density for antigen particles in samples of liver, bile, and stool was approximately 1.34 g/cm3. The fact that HA Ag particles can be recovered from chimpanzee liver, bile, and stool makes these potentially important sources of infectious and antigenic materials.

Animals↗

An outbreak of type B hepatitis associated with transfusion of plasma protein fraction.

An outbreak of type B hepatitis followed transfusion with a single lot of plasma protein fraction (PPF) at a 1200-bed hospital in June and July 1973. Of 51 recipients of the product, 31 were available as a study population and 19 (61%) had an illness compatible with hepatitis. Epidemiologic and serologic investigations provided firm evidence that this material was the vehicle for transmission of disease to its recipients. Recipients of four other PPF lots from the same manufacturer were studied. Two of these lots were also associated with extremely high clinical hepatitis attack rates (45% and 55%). The other two lots, which had been prepared from donor plasma contributing to the composition of the initially-studied PPF lot, failed to produced clinical illness, although one of these lots was associated with a high prevalence of hepatitis B seropositivity in recipients. Thus, a broad spectrum of clinical and serologic responses was evident in PPF produced from similar donor plasma and pasteurized in the same bulk container. This study is the first to incriminate heat-treated PPF in transmission of type B hepatitis and suggests the need for further studies of the effect of pasteurization cycles on inactivation of hepatitis B virus.

Antibodies, Viral↗

Unit dose radiopharmaceutical service as a component of total pharmacy practice.

A unit dose radiopharmaceutical distribution system as a component of total pharmacy services is discussed. The radiopharmacy functions of compounding, calibrating and distributing are rotated on a weekly basis among the staff pharmacists. The elution process and departmental policies and procedures are described. The pharmacist's unique expertise for preparing radiopharmaceutical doses is discussed.

Drug Compounding↗

Hepatitis A antigen isolated from liver and stool: immunologic comparison of antisera prepared in guinea pigs.

Morphologically similar hepatitis A antigen particles (HA Ag)3 have been detected in the stools of patients with type A hepatitis and in the livers of marmosets experimentally infected with hepatitis A virus. To investigate the humoral antibody responses to these antigens and to compare the immunologic properties of HA Ag from these two sources, we immunized guinea pigs with either marmoset liver-derived HA Ag or with human stool-derived HA Ag in complete Freund's adjuvant and measured their antibody responses by immune electron microscopy (IEM) and immune adherence hemagglutination (IAHA). Antibodies reacting with both hepatitis A antigens were elicited in both groups. As determined by IEM, no distinction was seen between the reaction of guinea pig antiserum to each HA Ag tested under code when reacted against either liver-derived or stool-derived HA Ag. Antibodies elicited to marmoset liver-derived HA Ag and human stool-derived HA Ag had similar end point dilution titers by IAHA when tested against either "light" density (1.34 g/cm3) or "heavy" density (1.40 g/cm3) stool-derived HA Ag or liver-derived HA Ag. Low levels of antibody to normal liver or stool control antigens were observed transiently but did not obscure the specific response to HA Ag. These data suggest that morphologically similar HA Ag particles from different sources and with different densities are immunologically similar and may be identical. In contrast to the heterogeneity of surface antigens of hepatitis B virus, the comparable immunogenicity and apparent antigenic homogeneity of HA Ags derived from various sources may simplify the approach to development of a vaccine against viral hepatitis, type A.

Animals↗

Immune response in fulminant viral hepatitis, type B.

Serial serum samples from the time of exposure until fatal outcome in 3 patients with fulminant viral hepatitis, type B, were examined for the presence of the antigens associated with hepatitis, type B, and their corresponding antibodies. The titers of hepatitis B surface antigen (HBsAg) were found to decrease by greater than 50% before death. Antibody to surface antigen (anti-HBs) was not detectable in any sample. Patterns of antibody to core antigen (anti-HBc)), HBsAg subtype "e" antigen, and anti- "e" were unremarkable, and could not be distinguished from those that might occur in many self-limited cases of hepatitis, type B. A rise in alpha-fetoprotein before demise suggests that late but inadequate liver regeneration occurred in these patients.

Adult↗

Induction of antibody to the "y" determinant of HBsAg in a chimpanzee carrier of HBsAg subtype "adw".

Antibody to the y determinant of hepatitis B surface antigen (HBsAg) was induced in a chimpanzee chronically infected with hepatitis B virus and circulating HBsAg subtype adw. The chimpanzee was immunized with purified preparations of HBsAg subtypes adw and ayw. Six weeks after immunization, antibody to HBsAg (anti-HBs) specific for the y determinant, appeared. No change occurred in titers of HBsAg or antibody to hepatitis B core antigen (anti-HBc) and "e" antigen remained detectable. The circulating HBsAg subtype adw remained present despite the persistence of anti-y for greater than 8 months.

Animals↗

The clinical problem of hepatitis transmission;.

Although blood banks in this country have been testing every unit of blood for hepatitis B surface antigen (HBSAg) by one of the highly sensitive "third generation" methods (radioimmunoassay or reversed passive hemagglutination) since September, 1975, post-transfusion hepatitis (PTH) still remains the major hazard to patients who require transfusion with blood and blood products. Since there may be an interval of many months between transfusion and onset of PTH and many cases are subclinical, the best data on the incidence of PTH have come from prospective studies with careful follow-up of transfused patients. Such studies first established the validity of HBSAg as a marker for the presence of hepatitis B virus (HBV), and they have shown a dramatic reduction in the incidence of post-transfusion type B hepatitis following the elemination of HBSAg positive blood from transfusion. Nevertheless, PTH cases not associated with HBV or HAV, which are termed non-A, non-B hepatitis, continue to occur commonly among transfused patients. Non-A, non-B hepatitis appears to be subclinical in many instances, but it can produce prolonged persistence of abnormal liver function tests, which may be associated with chronic liver disease. The outstanding risk factor responsible for the development of PTH has been shown to be blood from paid donors in every study which has evaluated this factor. HBSAg and anti-HBS prevalences were found to be much higher in paid donor groups than in voluntary donors. Accordingly, the Food and Drug Administration has proposed that all units of blood be labeled to indicate whether they were collected from voluntary or paid donors in order to inform consumers of the relative hepatitis risks of blood units from these different donor populations. In addition to HBSAg testing and reduced use of blood from paid donors, measures which may provide future reduction of the hepatitis hazard associated with blood transfusion include avoidance of unnecessary transfusions, identification of the agent(s) responsible for non-A non-B hepatitis and development of tests for these agents, idenfification and avoidance of blood from donors implicated in PTH cases, development of methods for immunizing transfused patients against the various agents responsible for PTH, and use of frozen-washed red blood cells for transfusion. Efforts to develop and/or evaluate these various approaches are currently being actively pursued in many laboratories.

Blood Donors↗

The prevalence of hepatitis B surface antigen in commercially prepared plasma products.

Commercially available lots of plasma derivatives prepared between 1957 and 1975 were tested for hepatitis B surface antigen (HBsAg) by radioimmunoassay. In all, 69 per cent of lots of plasma protein fraction, 40 per cent of factor IX concentrate, 20 per cent of normal serum albumin, 13 per cent of antihemophilic factor, 3 per cent of fibrinogen, and 0.7 per cent of immune serum globulin lots tested were HBsAg-positive. There was great variation in the prevalence of HBsAg-positive lots of each product among the different manufacturers, reflecting not only differences in methods of processing plasma, but also differences in donor populations. Those manufacturers relying upon volunteer donor plasma or placental source material demonstrated lower rates of HBsAg-positive lots of final products than those relying upon commercial donor plasma. There was a marked decrease in the prevalence of positive lots during the period 1971 to 1973, coincident with the onset of routine plasma donor screening for HBsAg. However, current requirements for plasma screening have not resulted in totally HBsAg-free plasma products. Use of more sensitive and more reliable tests for HBsAg will probably reduce contamination of plasma pools with HBsAg to undetectable levels. Despite HBsAg-status, however, the "high-risk" plasma products (fibrinogen, antihemophilic factor, factor IX concentrate) must still be considered capable of transmitting hepatitis and used only with the strictest indications.

Blood Proteins↗