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Biomedical subjects

J E Maynard

Publications and source records attributed to J E Maynard.

At least 145 records · Page 8Linked to original sources
PubMed1976

Experimental studies on the transmission of hepatitis B by mosquitoes.

Culex tarsalis and Aedes aegypti mosquitoes were fed on chimpanzees carrying hepatitis B surface antigen (HBS Ag) of known infectivity and pools were tested by radioimmunoassay daily for the presence of HBS Ag. HBS Ag continued to be detected at low levels in mosquito tissue after digestion of the blood meal. Inoculation of susceptible chimpanzees with macerated pools of A. aegypti mosquitoes at two intervals after digestion of the blood meal did not produce hepatitis or serologic evidence of hepatitis B virus infection. Mechanical transmission studies by interrupting feeding of A aegypti from HBS Ag-carrier chimpanzees and transferring them to susceptible chimpanzees did not produce hepatitis. These findings do not support the hypothesis that mosquitoes are involved in either biological or mechanical transmission of hepatitis B.

Aedes↗
PubMed1976

"e" Antigen, Dane particles, and serum DNA polymerase activity in HBsAg carriers.

Sera of 103 carriers of hepatitis B surface antigen were assayed for e-antigen and anti-e. Twenty-four were e-antigen-positive, 31 anti-e-positive, and 48 had neither detectable (e-negative). Aminotransferases were elevated in 75% of the e-antigen-positive carriers compared with 25% of e-negative carriers (P less than 0.001) and 13% of anti-e-positive carriers (P less than 0.001). Serum DNA polymerase activity was significantly higher in the e-antigen-positive carriers than in carriers without e-antigen. Dane particles were shown in 10 of 12 carriers with e-antigen, compared with one of 12 e-negative carriers (P less than 0.0003) and none of 12 anti-e-positive carriers (P less than 0.00003). These results suggest that ongoing hepatitis B viral replication is more active in e-antigen-positive carriers than in carriers without e-antigen, a finding that may help explain the high prevalence of chronic active hepatitis described in these individuals.

Adolescent↗
PubMed1976

Nosocomial viral hepatitis B. A cluster among staff with subsequent transmission to patients.

In a 2-month period four cases of hepatitis B occurred in hospital staff. Three months later two patients, hospitalized for open-heart surgery when the staff members had been infected, developed acute hepatitis B. Sera from all six ill individuals were subtype ayw and e-determinant positive. Epidemiologic investigation showed that the four staff had been exposed 3 months earlier to an asymptomatic hepatitis B surface antigen-positive (HBsAg) patient who was also e positive. To determine transmission from staff to patients study of 17 open-heart surgery patients was undertaken. Four of 17 were either HBsAg or anti-HBs positive. No correlation between infection and contact with three of four ill staff members or receipt of blood products was noted; however, 22 (46%) of 48 arterial blood gas specimens had been obtained from infected patients by one staff member, an inhalation therapist; this compared with seven (4%) of 157 specimens she obtained from control subjects (P less than 0.001). Furthermore, she handled indwelling arterial cannulae 25 (76%) of 33 times in infected patients compared with three (3%) of 95 times in control subjects (P less than 0.001). Transmission may have occurred via the arterial cannulae from a severe exudative dermatitis on the therapist's hands.

Adult↗
PubMed1976

Hepatitis A.

Hepatitis A is a disease of worldwide distribution which occurs in endemic and epidemic form and is transmitted primarily by person-to-person contact through the fecal-oral route. Common source epidemics due to contamination of food are relatively common, and water-borne epidemics have been described less frequently. The presumed etiologic agent of hepatitis A has now been visualized by immune electron microscopic (IEM) techniques in early acute-illness-phase stools of humans with hepatitis A as well as in chimpanzees experimentally infected with material known to contain hepatitis A virus. In addition, several new serologic tests for the detection of antibody against hepatitis A virus have been described. These include complement fixation and immune adherence techniques. Current data suggest that hepatitis A is caused by a single viral agent lacking the morphologic heterogeneity of hepatitis B viral components and that there may be relative antigenic homogeneity between strains of virus recovered from various parts of the world. Serologic studies to date also indicate that hepatitis A virus is not a major contributing cause in post-transfusion hepatitis.

Adolescent↗
PubMed1976

Isolation and characterization of hepatitis A virus.

This paper presents current isolation technics of hepatitis A virus (HAV) from human and chimpanzee stool, liver, and bile specimens, as well as comparative characterizations of HAV buoyant density properties of human and chimpanzee stool-derived particles. In addition, methods designed for the extraction and purification of HAV from large samples of stool and liver tissues, including agar gel filtration, are discussed in detail.

Animals↗
PubMed1976

Studies of the "e" antigen in acute and chronic hepatitis.

Sera from well individuals, including controls and asymptomatic HBsAg carriers, post-transfusion hepatitis cases, and chronic active liver disease patients were examined for the presence of "e" antigen and e antibody by rheophoresis. Our data confirm the specific association between the e determinant and hepatitis B infections and indicate that e antigen is closely associated with evidence of chronic hepatic dysfunction, in contrast to the association of e antibody with hepatic normalcy in HBsAg carriers. However, these correlations are not absolute and, therefore, it should not be inferred that all e antigen-positive individuals will develop chronic hepatitis nor, conversely, that presence of e antibody invariably protects against the development of chronic hepatitis.

Acute Disease↗
PubMed1975

e antigen and anti-e in HBsAg carriers.

A new antigen/antibody system, "e" and anti-e, was described in 1972. In order to assess the clinical significance of e antigen and anti-e, their presence was correlated with the clinical status, S.G.P.T. levels and liver biopsies of HBsAg carriers. 31 of the carriers had liver biopsies, 32 of 70 carriers had anti-e and 2 had e antigen. 28 of 55 carriers with normal S.G.P.T. and 4 of 15 patients with raised S.G.P.T. had anti-e. This difference is not statistically significant. 2 patients with e had raised S.G.P.T. All patients with normal histology, 45% of patients with mild, and 23% of patients with striking histological changes in the liver had anti-e. This association of anti-e with a normal or mildly abnormal liver was statistically significant. The 2 patients with e antigen had the most severe abnormalities in liver function and liver histology.

Alanine Transaminase↗
PubMed1975

Lack of causal association between Coxsackie B4 virus infection and diabetes.

An epidemic of Coxsackie B4 virus infection in an isolated group of islands in the Bering Sea in 1967 provided an opportunity to test the suggestion that infection with this virus might be associated with an increased incidence of diabetes. In 1973 islanders were tested by glucose-tolerance tests and their two-hour plasma glucose levels were analysed in the light of serological evidence of CB4 infection five years earlier. There was no evidence of any increased prevalence of diabetes in those who had been infected in 1967.

Adolescent↗
PubMed1975

An outbreak og gastroenteritis due to E. coli 0142 in a neonatal nursery.

A nursery outbreak of gastroenteritis casued by Escherichia coli 0142/K86/H6 is described. Over a period of nine months, 59 epidemiologically linked cases of diarrhea occurred, including 21 intractable cases with four deaths. The epidemic strain, which was not agglutinated by commerical diagnostic antisera, was isolated from the hands of personnel in five instances directly incriminated hand carriage as the mode of spread. Acquisition of illness, which was especially high among low-birth-weight infants less than 17 days old, did not correlate with any treatment modality investigated and appeared to be related to a host factor. Noninvasive small intestinal colonization, production of enterotoxin, and multiple antibiotic resistance of the epidemic strain were demonstrated and helped to explain the intractability of clinical illness in many infants, despite intensive parenteral antibiotic therapy. Surveys of fecal coliforms on the hands of nursery personnel revealed no change in prevalence after introduction of a policy of "triple" handwashing with 3 percent hexachlorophene soap, but a significant decrease occurred during the use of disposable gloves. The frequent occurrence of E. coli 0142 in throat swabs of affected infants suggested that pharyngeal colonization may serve as an important diagnostic clue in E. coli diarrhea.

Age Factors↗
PubMed1975

Hepatitis A: report of a common-source outbreak with recovery of a possible etiologic agent. I. Epidemiologic studies.

From the end of October to the end of December 1973, an epidemic of hepatitis A affected 40 students at a state university, 11 employees of two restaurants, and 11 other residents in a southwestern metropolitan community. Two distinct epidemic waves of illness occurred, and investigation implicated two local restaurants as sources of infection, one for each epidemic wave. An index patient who prepared food was identified at each restaurant, and the two restaurants were linked by the fact that the index patient who worked at the second restaurant had patronized the first restaurant. Foods implicated as vehicles of transmission included 'guacamole,' green salad, spaghetti, and hamburger. The findings represent a rare example of a 'double' common-source outbreak with two distinct epidemic waves related to two separate eating establishments.

Arizona↗
PubMed1975

Hepatitis A: report of a common-source outbreak with recovery of a possible etiologic agent. II. Laboratory studies.

During investigation of a food-borne outbreak of hepatitis A among university students in a southwestern metropolitan community, immune electron microscopic examination of a concentrated stool suspension pooled from seven acutely ill individuals revealed viruslike particles 17-nm in diameter. These particles were initially coated by antibody contained in the convalescent-phase serum of one of the ill students as well ad by antibody in convalescent plasma of a prison volunteer originally infected with the MS-1 strain of hepatitis A virus. Rises in titer of antibody to this particle were demonstrated by immune electron microscopy in acute and convalescent sera from student patients as well as in pre-inoculation and convalescent sera from the prison volunteer. Two chimpanzees inoculated intravenously with the concentrated preparation of pooled human stools developed viral hepatitis. During acute illness their feces contained particles morphologically identical to those in the inoculum. These findings represent the first reported recovery of the presumed etiologic agent of hepatitis A from a naturally occurring community outbreak of disease in the United States.

Acute Disease↗
PubMed1975

Hepatitis B virus infection in chimpanzees: titration of subtypes.

Thirty-four chimpanzees were inoculated with sera containing the adw, ayw, adr, or ayr subtype of hepatitis B surface antigen (HBs Ag). Twenty-nine of the animals became infected with hepatitis B virus, and in every instance the subtype of HBs Ag in the infected animal was the same as the subtype in the inoculum. Infectivity titers were established for the adw and ayw inocula. The patterns of serologic events varied in the infected animals but included most of the typical patterns of serologic change seen in human cases of type B hepatitis. Mild disease, manifested by elevated concentrations of serum enzymes and changes detected by liver biopsy, occurred in 23 of the 29 infected animals.

Animals↗
PubMed1975

Epidemiology of hepatitis B in hospital personnel.

To identify occupational categories and work areas of possible risk for acquisition of nosocomial hepatitis B by hospital personnel, serologic sampling for hepatitis B surface antigen (HBSAg) and antibody (anti-HBS) by radioimmunoassay was carried out in 513 employees of a large metropolitan hospital serving predominantly indigent patients. HBSAg was detected in 0.7%, HBSAg and anti-HBS in 0.4%, and anti-HBS in 13.3% of the study population. No significant difference in seropositivity was noted between sexes. Furthermore, neither exposure to patients with hapatitis nor previous blood transfusion correlated with serologic evidence of hepatitis B infection. However, frequency and intensity of exposure to blood products was associated with serologic evidence of infection: 18.9% of those with frequent blood contact were positive for HBSAg or anti-HBS, compared with 11.4% of those without blood product exposure (p less than .05). Direct patient contact, apart from blood exposure, did not appear operative as a major factor in hepatitis B transmission in this population. Accordingly, occupational categories and work areas with highest risk for acquisition of nosocomial hepatitis B were those with greatest blood exposure.

Adult↗