ABSTRACT
Foetal calf serum present in the media used for cryopreservation was replaced by various synthetic polymer such as gelatin, glycerol, carboxymethyl cellulose and dimethyl sulphoxide at various concentration. Growth pattern of cells, % survival and karyological studies have been done in the present study. It was found that optimum concentration of carboxymethyl cellulose was 0.1% in combination with 10% glycerol and 10% DMSO. At this concentration percentage survival of cells was found maximum and karyotype was found normal without any abnormality in the chromosomes. It was concluded from the study that serum free media can be employed for the cryopreservation of these cells which are further used for production of tissue culture vaccines without causing any adverse affects.
Subject(s)
Animals , Carboxymethylcellulose Sodium/pharmacology , Cell Line , Cryopreservation/methods , Cryoprotective Agents/pharmacology , Culture Media, Serum-Free/standards , Dimethyl Sulfoxide/pharmacology , Glycerol/pharmacology , Kidney/cytology , RabbitsABSTRACT
BACKGROUND. One hundred and sixty million doses of measles vaccine have been used since the Expanded Programme of Immunization began in 1985. Mild-to-moderate vaccine reactions are not infrequent and are accepted by parents but occasionally severe reactions and even death occur. We studied these severe reactions. METHODS. From 1986 to 1994, 1762 batches of measles vaccine were tested and found to be satisfactory by the World Health Organization criteria. These were released for mass immunization. RESULTS. After 40 reported incidents of severe reactions or deaths in the field, 59 intact samples of vaccine produced by different manufacturers were tested and found to be safe, i.e. they were not toxic and were sterile. However, on testing reconstituted or used vials a few were found to be toxic and many were unsterile. Reactions occurred in 115 vaccinees resulting in death of 79 children. These reactions were characterized by high fever, vomiting and profuse watery diarrhoea resulting in death within 24 hours. CONCLUSIONS. Reactions to the vaccines were more likely to be related to the toxic shock syndrome due to the use of unsterile syringes and needles and perhaps the use of reconstituted vaccines beyond their specified time for administration resulting in contamination.
Subject(s)
Animals , Child , Drug Contamination , Guinea Pigs , Humans , India , Measles Vaccine/adverse effects , Mice , Vaccination/adverse effectsABSTRACT
Since transplacental immunity and waning of maternally derived measles specific antibodies play an important role in determining the optimum age for vaccination of infants against measles, a study was carried out in which 150 paired samples and 581 infant serum samples were tested for measles specific antibodies. Out of these paired samples, 132 pairs showed measles antibodies in both mother and cord. HAI antibody was absent in 3 paired samples whereas, 5 mothers could not pass on the antibodies in the cord samples. In the remaining 10 serum samples only cord blood showed the presence of antibodies without the detectable level of antibodies in mother. Statistically no significant difference between the mother and cord blood titers was observed by applying the student 't' test for comparison of the mean (t = 0.01). Analysis of 581 infant serum samples for prevalence of maternal antibodies indicated that 83% of the samples at the age of 3 months or below had measles antibodies but with the increase in age there was tremendous loss with only 19-20% at the age of 6-7 months. After 7 months the percentage of infants which had antibody varied from 11-13%. There was negative correlation between age and seropositivity (r = -0.72) which was highly significant (p < 0.05).
Subject(s)
Age Distribution , Female , Humans , Immunity, Maternally-Acquired , Immunization Schedule , Infant , Infant, Newborn , Longitudinal Studies , Measles/immunology , Measles Vaccine/administration & dosage , Pregnancy , Regression Analysis , Serologic TestsABSTRACT
Twenty diarrhoeal isolates identified as Esch. coli O157 were screened for cytopathic activity on the continuous Vero cell line. Of these, seven strains (35%) showed cytopathic effect which was maximum on the 4th day after inoculation, with a maximum titre of 1 in 128. The total loss of cytopathic activity was observed in the positive filtrates subjected to a temperature of 100 degrees C for 15 min, while heating at 65 degrees C for 15 min, resulted in partial loss of this activity. All the verocytopathic strains were obtained from infants and children and were devoid of heat labile (LT) and heat stable (ST) toxins as well as enteroinvasive property.