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M S Balayan

Publications and source records attributed to M S Balayan.

30 records · Page 2Linked to original sources
PubMed1987

Non-A, non-B fulminant viral hepatitis in France in returnees from Asia and Africa.

Among 61 patients admitted for non-A, non-B fulminant viral hepatitis to Hôpital Beaujon, 10 had returned from Asia or Africa, and 51 had not been outside France, within the month preceding jaundice. This suggests that hepatitis might have been contracted in Asia or Africa in the former, and in France in the latter. The interval between the onset of jaundice and the onset of hepatic encephalopathy was 10 days in the former and 26 days in the latter (P less than 0.03). The serum of the patient returning from Asia contained, and the sera of the nine patients returning from Africa did not contain, antibodies to a virus isolated from the stools of patients suffering from an epidemic fecal-oral non-A, non-B viral hepatitis in Central Asia. It is concluded that infection with Asian-African non-A, non-B viruses can be the cause of fulminant hepatitis in persons returning from these countries, that the course of this type of non-A, non-B fulminant viral hepatitis is shorter than that of non-A, non-B fulminant hepatitis contracted in France, and that different viruses might be responsible for non-A, non-B hepatitis in Asia and Africa.

Adult↗
PubMed1986

Antibody to hepatitis A virus after overt and asymptomatic hepatitis A infection.

The titres of antibody to hepatitis A virus (anti-HAV) were found to fall rapidly during 3-4 years after hepatitis A and more slowly thereafter, though they never reached undetectable levels in at least 23 years. The levels of anti-HAV in convalescents after overt hepatitis A were found to be significantly much higher than in those who had anti-HAV as a result of asymptomatic infection.

Age Factors↗
PubMed1984

Antibody response in hepatitis A and some other enteroviral infections: quantitative comparison.

Antibody levels produced in humans in the course of hepatitis A were compared with those in Coxsackie B2 infection and vaccination with live poliovaccine (type 1) using the method of immune-electron microscopy. It has been shown that the levels of antibody in hepatitis A were 25 to 800-times higher than in Coxsackie B2 infection and than after vaccination with the live poliovaccine.

Animals↗
PubMed1983

Evidence for a virus in non-A, non-B hepatitis transmitted via the fecal-oral route.

Typical acute hepatitis was reproduced in a human volunteer immune to hepatitis A virus (HAV) after oral administration of pooled stool extracts from presumed cases of epidemic non-A, non-B hepatitis. Markers of hepatitis B infection, anti-HAV IgM, and increase in total anti-HAV level were not detectable in the volunteer's sera during the course of infection. Spherical 27- to 30-nm virus-like particles were visualized by immune electron microscopy (IEM) in stool samples collected during preclinical and early postclinical phases. These particles banded in CsCl at a buoyant density of 1.35 g/cm3. They reacted in the IEM test with sera from individuals who had experienced two non-B hepatitis episodes but did not react with sera from routine anti-HAV IgM-positive hepatitis patients. Intravenous inoculation of cynomolgus monkeys with the virus-containing stool extract resulted in histopathologically and enzymatically confirmed hepatitis, excretion of virus-like particles, and antibody response to them.

Feces↗
PubMed1983

Enzyme-immunoassay in the diagnosis of human hepatitis A: specific and non-specific reactions.

Solid-phase enzyme-immunoassay (EIA) used for the detection of hepatitis A virus (HAV) often reveals a non-specific activity which can be reduced or fully eliminated in the presence of normal serum. The factor responsible for this activity appeared to be a non-viral EIA-active material (NVEAM) that non-specifically reacted with normal serum of some mammalian species (human, monkey, rabbit, cattle). The HAV and NVEAM have been separated by CsC1 gradient centrifugation, where the HAV banded in a narrow zone at 1.34 g/cm3, whereas the NVEAM could be found in a wider zone with an average density of 1.31 g/cm3. Non-immunological character of the non-specific activity was demonstrated by the inhibitory effect of weak non-ionic detergents (0.05% Tween 20 or bile, 1:500). The conditions for preferential binding of the HAV by immune sera and elimination of non-specific reaction have been determined.

Animals↗
PubMed1982

The spread of hepatitis A virus in connection with hepatitis cases in children's communities.

In order to investigate the characteristics of hepatitis A virus excretion, 372 children in semi-closed day-care centres were examined at the time of the seasonal increase in hepatitis incidence. Enzyme immunoassay and immune electron microscopy were used to detect virus in faeces. Ten communities were surveyed and, for the purposes of this paper, were divided into four groups on the basis of the observed pattern of virus excretion. The first group consisted of 4 communities with one hepatitis case in each; in this group, there was a relatively low rate of virus excretion throughout the study. The second group comprised 2 communities with one or two hepatitis cases; this group was characterized by an increase in the rate of virus excretion some time after isolation of the patient. In the communities of the third group, there were numerous hepatitis cases and a high rate of virus excretion during the first weeks of observation, followed by a significant decrease. There were no hepatitis cases in the fourth group, but some hepatitis A virus shedding was detected.The ratio of the number of cases to the number of virus carriers was 1:11.4 in the first two groups, and 1:3.4 in the third. Administration of normal serum immunoglobulin did not significantly affect the rate of HAV excretion. The cause of the differences in shedding of hepatitis A virus in the communities is unknown, but may possibly be related to the size of the immune section of the population.

Antibodies, Viral↗
PubMed1976

Some characteristics of poliovirus strains isolated in Uganda between 1966 and 1971.

Sixty-five poliovirus strains were investigated in genetic marker tests in order to obtain information on the characteristics of polioviruses circulating in Uganda where, owing to the insufficient use of live poliovirus vaccine, poliomyelitis remained a serious public health problem. Of the type 1 strains predominant in both epidemic and non-epidemic years, 29 were studied for their antigenic fine structure. Based on their intratypic character, these strains proved to represent six different antigenic variants. Three of these variants were predominant during certain periods; the first variant was present in 1966 and 1968, the second in 1967, and the third from 1969 to the end of observation period. Four strains from Kuwait and three from Ghana isolated in 1969 and 1970 showed an antigenic structure identical to that of the strains predominant in Uganda in these years. Some strains proved to be of vaccine origin. Twenty-nine type 1 and 24 type 2 strains showed a great variety of characteristics when studied in d, od, and rct/40 marker tests. There was no indication that the distribution of strains according to their in vitro markers would have been different in epidemic and non-epidemic years, or that any particular combination of markers would have been more common among strains isolated from paralytic patients than among those from non-paralytic patients. Nine of 12 type 3 strains had the rct/40(+) marker.

Antigens, Viral↗
PubMed1974

Factors affecting the efficacy of live poliovirus vaccine in warm climates. Efficacy of type 1 Sabin vaccine administered together with antihuman gamma-globulin horse serum to breast-fed and artificially fed infants in Uganda.

A virologically controlled field trial was conducted with live monovalent type 1 poliovirus vaccine in children aged 3-30 months living in a rural area of Uganda, in an attempt to find out the reason for the poor efficacy of such vaccine often observed in countries with a warm climate. Groups of breast-fed and of artificially fed infants received the vaccine orally, either alone or mixed with horse serum prepared against partly purified human gamma-globulin. Irrespective of the diet, the "take rate"-measured by the rates of vaccine virus excretion and of antibody conversion-was found to be poor when the vaccine was given alone but satisfactory when it was given together with the horse antiserum. However, the extent and duration of vaccine virus multiplication in the intestinal tract proved to be limited and the mean antibody level elicited by the vaccination, irrespective of the schedule of vaccine administration, was low. These results, besides indicating that breast-feeding does not influence the efficacy of vaccination in the age groups studied, revealed the presence of an inhibitor in the alimentary tract. This inhibitor acts against the multiplication of vaccine virus, which may be blocked by antibodies in the horse antiserum for a limited period at the time of vaccination. Interference between the enteroviruses and the vaccine strain was also found to be responsible for decreasing the efficacy of vaccination, though its role was secondary to that of the inhibitor. Revaccination experiments showed that the effects of both inhibitor and interference may be overcome by repeated administration of the vaccine.

Breast Feeding↗