Hepatitis A virus (HAV) was isolated directly from human feces and propagated serially in an HBsAg producing human hepatoma cell line. No cytopathic effect was observed in the tissue culture and no detectable amounts of HAV were present in the tissue culture supernatant fluid. However, increasing amounts of hepatitis A antigen (HAAg) were detected by radioimmunoassay in the cell extracts obtained by freezing and thawing of cells. Specificity of the HAAg determination was shown by neutralization with convalescent sera of marmosets experimentally infected with the MS-1 strain of hepatitis A and by the absence of this neutralization with preinoculation sera. HAAg was first detected after four weeks in the cell extract of infected cultures after inoculation of 10(2)--10(4) tissue culture infectious doses of HAV from second passage.
In acute and chronic hepatitis B, antibodies of the immunoglobulin M (IgM) class against the hepatitis B core antigen (anti-HBc IgM) have been demonstrated. For the determination of anti-HBc IgM, a sensitive enzyme immunoassay with anti-mu-coated flat-bottomed microtiter plates is described and evaluated. The specificity of the anti-HBc IgM test system was proven by pretreatment of presumed anti-HBc IgM-positive samples with anti-mu to block anti-HBc IgM. The test system was highly sensitive. In the acute stage of hepatitis B, anti-HBc IgM could be demonstrated in serum dilutions up to 10(-7) (mean titer, 10(-5)), and in sera from patients with chronic hepatitis B, the mean titer was 10(-3). In a study of unselected patients whose sera were sent at irregular intervals for testing, anti-HBc IgM persisted in a high percentage (52%) for at least 13 to 18 months after onset of illness despite the fact that these patients eliminated hepatitis B surface antigen (HBsAg) and produced antibodies to HBsAg (anti-HBs). By using the anti-HBc IgM test as an additional aid in the diagnosis of acute HBsAg-negative hepatitis, the hepatitis B etiology could be established in 13 of 42 patients (31.4%). Investigations of the prevalence of anti-HBc IgM in different groups of patients with chronic hepatitis B infection showed 89.4% anti-HBc IgM-positive results in patients with chronic active hepatitis B, 60% in patients with HBsAg-negative chronic active hepatitis, 58.2% in patients with primary liver carcinoma and markers of hepatitis B infections, and 34.9% in healthy carriers of HBsAg.
The published knowledge on neurobiological, psychological, and ethological aspects of development in Callithrix jacchus is still limited. We have collected published and unpublished data from several Callithrix colonies and pooled information on criteria for developmental progress and maturation using a questionnaire sent to numerous experts in the field. The data suggest that developmental stages can be defined not only for the embryonic and fetal but also for the postnatal period. Based on multifactorial definitions, using criteria selected from maturational changes in the motor and visual systems and behavioral features, we propose to subdivide postnatal development of the common marmoset into seven periods (“stages”).
Three methods were compared for determining anti-HAV of the IgM class. In the first method flat-bottomed microtiter plates coated consecutively with anti-HAV of the IgG class and HAAg were incubated with patient serum and, after washing, peroxidase conjugated anti-mu was added. After subsequent incubation with substrate the enzymatic reaction was stopped and the optical density was measured. In the second method the solid phase was coated first with antibodies to IgM and after incubation with patient serum and subsequent incubations with HAAg and 125I anti-HAV of the IgG class radioactivity was counted. These two methods were compared with reorienting sucrose gradient ultracentrifugation, an established method for demonstrating specific IgM antibodies. The persistence of IgM anti-HAV in 103 sera drawn at different times after onset of jaundice was evaluated. Sera drawn up to 30 days after onset of hepatitis A were IgM anti-HAV positive with both of the first two methods. Forty-one to 90 days after onset of illness IgM anti-HAV could be demonstrated with the first method in 47% of the patients, in 94% with the second method, and in 82% with gradient centrifugation. The second method was most sensitive and could be adjusted so that at a serum dilution of 1:10(4) anti-HAV IgM was detected only up to six months after infection. In contrast to the first method, nonspecific reactions caused by rheumatoid factor were not detected with the second method. During a one-year period about 15,000 sera of patients with clinical diagnoses of acute hepatitis were tested; the positive results correlated well with the clinical data, and there was no indication of nonspecific positive results.
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