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Biomedical subjects

J E Maynard

Publications and source records attributed to J E Maynard.

At least 109 records · Page 6Linked to original sources
PubMed1979

Non-A, non-B hepatitis among participants in a plasmapheresis stimulation program.

Non-A, non-B hepatitis was transmitted to seven of nine participants in a red blood cell-stimulation program following transfusion of blood from one asymptomatic donor. Five of the seven patients had clinical as well as biochemical evidence of infection, and three of these five were icteric. Incubation periods for the clinical cases ranged from 28 to 50 days, and duration of illness was from two to eight weeks. None of the seven patients showed serologic evidence of acute infection or reinfection with hepatitis A virus, hepatitis B virus, cytomegalovirus, or Epstein-Barr virus. Viremia persisted in the donor for at least 34 days, since non-A, non-B hepatitis was transmitted to program participants during that period.

Adult↗
PubMed1979

Hepatitis B e-antigen and its correlation with other serological markers in chimpanzees.

Three chimpanzees experimentally infected with hepatitis B virus, and another three chimpanzees that were hepatitis surface antigen carriers, were studied for the presence of viral antigens and humoral immune responses. Quantitative analyses of hepatitis B surface and e-antigens in sequential serum samples at early acute stages revealed cyclic oscillations of these two antigens following a synchronous pattern. Similar analyses of anti-e-antigen and anti-hepatitis B core antigen antibodies from the three experimentally infected primates indicated that peak titers of these two antibodies occurred as surface antigen decreased to undetectable levels. Of the three surface-antigen carriers, two were positive for e-antigen and one was positive for e-antigen antibody for the entire course of surveillance (8, 9, and 22 months, respectively).

Animals↗
PubMed1979

Serodiagnosis of viral hepatitis A by a modified competitive binding radioimmunoassay for immunoglobulin M anti-hepatitis A virus.

A competitive binding radioimmunoassay (CBA) for antibody to hepatitis A virus (HAV) was evaluated and compared with a standard solid-phase radioimmunoassay for anti-HAV, CBA was found to be sensitive and specific for the detection of anti-HAV, as demonstrated by the 98% concordance of CBA and solid-phase radioimmunoassay test results. The standard CBA test was modified for the differential detection of acute (immunoglobulin M) and convalescent (immunoglobulin G) anti-HAV by incorporation of a step in which immunoglobulin G anti-HAV was preferentially absorbed with S. aureus cells (protein A). The modified CBA test was shown to be capable of differentiating between acute- and convalescent-phase sera. The modified CBAM test was able to detect immunoglobulin M anti-HAV up to approximately 4 weeks after the onset of illness.

Acute Disease↗
PubMed1979

Guidelines for the care of patients hospitalized with viral hepatitis.

For years patients hospitalized with viral hepatitis have been placed in two categories of isolation--enteric precautions and blood precautions. This strategy was based on the inability to differentiate between hepatitis A and B and on the assumption that feces and blood from patients with either type might be infective. It is now known that patients with hepatitis A do not pose a problem of disease transmission through direct contact with blood, and although blood of patients with hepatitis B may be infective, the virus is not transmitted via feces. The enteric route is the principal mode of transmission for hepatitis A, but maximal levels of hepatitis A virus excretion occur before the onset of jaundice. Non-A, non-B hepatitis is similar epidemiologically to hepatitis B. Thus, the major thrust for caring for patients hospitalized with viral hepatitis is toward blood precautions; the same precautions used when handling feces, urine, and excretions from all other hospitalized patients are appropriate for patients admitted with a diagnosis of hepatitis A.

Bedding and Linens↗
PubMed1978

Hepatitis B infection in physicians. Results of a nationwide seroepidemiologic survey.

To define the epidemiologic features of occupationally acquired hepatitis B infection among physicians, we conducted a seroepidemiologic survey of physicians attending three American Medical Association conventions in 1975 and 1976. Of 1,192 participating physicians, 220 (18.5%) had serologic evidence of prior hepatitis B virus infection (positive hepatitis B surface antibody). The infection rate was higher among those practicing in urban communities; it increased with the number of years in practice; and among specialties, it was highest in pathologists (27%) and surgeons (28%). The serologic data demonstrated a changing pattern of viral hepatitis related to entry into the medical profession, with hepatitis B accounting for a majority of clinical hepatitis experienced after beginning medical practice.

Adult↗
PubMed1978

Passive immunization against hepatitis B: a review of recent studies and comment on current aspects of control.

Several independent studies suggest that both hepatitis B immune globulin (HBIG) made from plasma pools containing high titers of anti-HBs and standard immunoglobulin (IG) containing some anti-HBs may be effective for pre- and post-exposure prophylaxis of hepatitis B. Based on a synthesis of current data, it seems reasonable to recommend HBIG for the post-exposure prophylaxis of individuals sustaining accidental needle stick or mucosal exposure to blood known to contain hepatitis B surface antigen (HBsAg). If HBIG is unavailable there is also reason to expect that administration of standard IG which contains some anti-HBs may confer benefit. Although available data regarding prophylaxis of infants born to mothers with HBsAg positive hepatitis at time of delivery are insufficient to warrant firm recommendations on globulin administration, a temporary set of guidelines supporting use of either HBIG or standard IG containing some anti-HBs seems warranted in view of the serious implications for induction of the HBsAg chronic carrier state in infancy. Because appropriate environmental control measures may significantly reduce the transmission of hepatitis B in certain endemic settings such as hemodialysis units or homes for the mentally retarded, IG prophylaxis in these surroundings cannot be routinely recommended. Since current data show no evidence for superiority of HBIG over standard IG in these settings, and because there is some evidence that use of lower anti-HBs titer globulins may provide for acquisition of passive-active immunity, it seems reasonable to suggest that if IG is to be used for pre-exposure prophylaxis, the material to be used should be standard IG containing some anti-HBs.

Antibodies, Viral↗
PubMed1978

Purification and partial characterization of hepatitis e antigen (HBeAg).

Purification of hepatitis e antigen (HBeAg) from 200 ml of chimpanzee plasma was accomplished by a combination of ion-exchange chromatography on diethylaminoethyl-cellulose followed by gel filtration. High-resolution sodium dodecyl sulfate-polyacrylamide gel electrophoresis of purified HBeAg demonstrated two major polypeptides with estimated molecular weights of 22,000 and 55,000. HBeAg labeled with 125I showed a high affinity for protein A-conjugated Sepharose CL-4B. The precipitation reaction between HBeAg and anti-HBe was inhibited by preincubating the purified antigen with rabbit anti-human immunoglobulin G (IgG). These data show that HBeAg is associated with a serum fraction with the biophysical and antigenic properties of an immunoblobulin of the IgG class. Sedimentation coefficient analysis of purified HbeAg resulted in an S20w value of 11.6 and a molecular weight value of 324,000. These findings, supported by gel filitration and polyacrylamide gradient gel electrophoresis, revealed that HBeAg has properties analogous to those of a dimer of IgG.

Animals↗
PubMed1978

Experimental infection of marmosets with hepatitis A virus.

Saguinus mystax marmosets were experimentally infected with two strains of human hepatitis A virus. One of these strains of HAV was successfully subpassaged in this species of marmosets. In another experiment, the 1.32 and 1.41 g/cm3 buoyant density species of HAV derived from an infected chimpanzee stool were shown to be infectious in three species of marmosets. The value of the marmoset as an experimental model for hepatitis A infection was demonstrated by these studies.

Animals↗
PubMed1978

Evaluation of a finger prick blood collection method for the seroepidemiology of hepatitis B.

A finger prick-swab method of blood specimen collection was qualitatively and quantitatively compared with the conventional venipuncture method for HBsAg and anti-HBs determinations by radioimmunoassay (RIA). The new method consisted of pricking the finger, collecting 0.1-0.2 ml of blood with a cotton-wool swab, and eluting the swab in 1 ml of 1% bovine albumin in saline containing 0.1% sodium azide. Using chimpanzees seropositive for HBsAg or anti-HBs, comparisons were made of RIA results of: (a) whole blood, haemolysed blood, serum, and plasma; (b) paired finger prick samples and serum; (c) dilutions of finger prick samples and serum; and (d) different volumes of blood on swabs. Field studies were carried out at two institutions where hepatitis B was hyperendemic to compare results from paired finger prick and serum specimens assayed by the RIA and haemagglutination techniques. The laboratory studies showed that swab RIA values for anti-HBs were significantly lower than serum values and that for HBsAg, swab values were significantly higher than serum values. In HBsAg tests, the field studies showed 100% agreement between the two methods; in anti-HBs tests, the finger prick method showed 85% agreement with positive sera. Because of the logistics of collecting and processing blood serum, the finger prick-swab technique may be a valuable aid in large-scale seroepidemiological surveys for hepatitis B.

Antibodies, Viral↗
PubMed1978

Radioimmunoassay for the detection of hepatitis e antigen (HBeAG) and antibody (anti-HBe).

A solid phase micro-immunoradiometric assay (micro-SPIRA) for the detection of hepatitis e antigen (HBeAg) and antibody has been developed. Chimpanzee anti-HBe/2 was developed by repeated immunizations with purified antigen containing HBeAg/1 and HBeAg/2. An anti-HBe/2 titer of 1:4 was determined by immunodiffusion (ID) analysis. Anti-HBe/1 was not detected. The anti-HBe IgG used in the assay was purified from plasma by a combination of DEAE-cellulose and affinity chromatography. The sensitivity of the micro-SPIRA for antigen and antibody was 193 ng/ml and 65 ng/ml, respectively. By comparing relative endpoint titers obtained by ID to micro-SPIRA, it was determined that micro-SPIRA for antigen and antibody is 320 and greater than 1300 times more sensitive, respectively, than ID. The specificity of the assay was ascertained by the examination of various non-B specimens. The application of the assay to a panel of 50 hepatitis B surface antigen (HBsAg)-positive specimens resulted in an increase in positivity of 18% for antigen and 22% for antibody.

Animals↗
PubMed1977

Cyclic excretion of hepatitis A virus in experimentally infected chimpanzees: biophysical characterization of the associated HAV particles.

Experimental infection of two chimpanzees with the Phoenix Antigen strain of HAV resulted in the cyclic excretion of virus particles on days 9-11, 14-15, and 20-21 postinoculation. Isopycnic banding in CsCl of stool suspensions prepared from 9-11; 14-15; and 17, 19, 21 dav stool pools revealed multiple buoyant densities for the associated HAV particles. Hollow HAV particles found in the 9-11 day pool banded primarily at a buoyant density of 1.30 g/cm3. HAV in the 14-15 day stool banded bimodally in a CsCl gradient, with antigen peaks at buoyant densities of 1.29 and 1.33 g/cm3. HAV in the days 17, 19, 21 stool pool also banded bimodally in a CsCl gradient; however, the antigen peaks occurred at buoyant densities of 1.33 and 1.40 g/cm3.

Animals↗
PubMed1977

Multiple buoyant densities of hepatitis A virus in cesium chloride gradients.

Hepatitis A virus (HAV) recovered from stools of human cases of hepatitis A and from stools of chimpanzees experimentally infected with HAV was shown to possess multiple buoyant densities in CsCl gradients. The greatest proportion of HAV was most frequently found at a buoyant density of 1.32-1.34 g/cm3, however, large proportions of HAV were also frequently found at higher densities, including 1.36-1.37, 1.40-1.42, and 1.45-1.48 g/cm3. These findings are consistent with the notion that HAV may be a parvovirus.

Animals↗
PubMed1977

Epidemiology of hepatitis B in two Alaska communities.

In 1973, epidemiologic and serologic data related to hepatitis B infection were collected from the residents of two remote Alaskan Eskimo villages located in an area of high hepatitis incidence. A total of 418 sera were tested by solid-phase radioimmunoassay for heaptitis B surface antigen (HBsAg) and antibody to that antigen (anti-HBs). The overall infection prevalence of 54.8% in the two villages included a 13.9% prevalence of HBsAg and a 40.9% prevalence of anti-HBs. Families containing an individual with HBsAg had significantly higher infection prevalence than those without an antigen carrier. Larger households had higher proportions of infected members than smaller households. The data suggest that efficient transmission of hepatitis B virus occurs within the household setting in these villages by other than classically established parenteral routes.

Adolescent↗