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Biomedical subjects

S N Saxena

Publications and source records attributed to S N Saxena.

At least 19 recordsLinked to original sources
PubMed1994

Effect of casitone and fructose on the growth of Lactobacillus acidophilus and its survival during storage.

Supplementation of milk with combination of casitone (0.5% (w/w)) and fructose (0.5% (w/w)) resulted in greater acid production, higher viable counts, increased sugar utilization and shorter generation time for the L. acidophilus strains tested. The experimental product prepared by using these additives contained 1.5-2.0-fold more viable L. acidophilus than the control (no additives) throughout 21 days of storage. Further, both control and experimental products remained acceptable throughout the storage period. However, the former was rated superior in flavor, whereas the latter exhibited better texture.

Animals↗
PubMed1992

Comparative stabilities of glutaraldehyde & heat inactivated pertussis vaccine components of adsorbed DPT vaccine with different preservatives.

The stability of pertussis component (glutaraldehyde or heat inactivated pertussis vaccine) of the adsorbed diphtheria-pertussis-tetanus (DPT) vaccine preserved in thiomersal or benzethonium chloride was studied at 4-8 degrees C and 35 degrees C for 30 days. The potency of pertussis component of adsorbed DPT vaccine preserved with benzethonium chloride was lower than that preserved with thiomersal. After the initial loss of potency of pertussis component in the benzethonium chloride during blending, the stability of potency of pertussis component at 4-8 degrees C and 35 degrees C for 30 days was similar for vaccines preserved with either benzethonium chloride or thiomersal. The stability of both types of pertussis components inactivated with glutaraldehyde or heat was also similar at both the temperatures for 30 days.

Diphtheria-Tetanus-Pertussis Vaccine↗
PubMed1991

An efficient method for production of purified inactivated Japanese encephalitis vaccine from mouse brains.

The efficiency of production of purified Japanese encephalitis (JE) vaccine from mouse brains was increased by reprocessing the brain material after recovery of the virus and by pooling of a few extra fractions after zonal ultracentrifugation. By the routine production method, one mouse yielded approximately 2.5 doses of the vaccine while the improved method gave about five doses from each mouse. All the batches of purified JE vaccine made by improved technology passed all the quality control tests as specified by the Minimum Requirements for biological products of the Japanese Government and World Health Organization.

Animals↗
PubMed1991

The quantitation of rabies-specific antibodies. I. Modified counter immunoelectrophoresis. A rapid and sensitive method.

Modified counter immunoelectrophoresis was standardized with respect to dilution of tissue culture antigen and indicator serum, the incubation time for neutralization and the effect of an electric current. The technique was found to be sensitive enough to detect a minimum level of antibodies (0.5 IU/ml) by using a 16 mA current per slide for 2 h, indicator serum of 15 IU/ml and the use of an antigen at a concentration of 1:35. Above all, the incubation period did not affect the neutralization of the virus. The test was also applied to the detection of rabies-specific antibody levels in 73 human sera. The test was found to be simple, quick and economical for titration of rabies antibodies.

Antibodies, Viral↗
PubMed1991

The quantitation of rabies-specific antibodies. II. Factors affecting the sensitivity of the haemagglutination inhibition test.

Various factors affecting the HAI test for the quantitation of rabies-specific antibodies have been evaluated with a view to obtaining maximum sensitivity and reproducibility in tests using tissue culture antigens prepared in vero cells and concentrated by dialysis. Goose erythrocytes treated with proteolytic enzyme bromelian at a concentration of 0.025% were much more susceptible to HA than those that were untreated or erythrocytes treated with neuraminidase. In addition, other parameters like the use of a phosphate buffered saline (PBS) as a diluent at pH 6.2, incubation at 0-4 degrees C for 1.5-3 h were found to be most critical for achieving maximum HA activity. To remove non-specific inhibitors, serum samples were treated with aerosil, acetone in combination or alone. Of the 73 serum samples tested, removal of non-specific inhibitors by aerosil alone occurred in up to 54.79% of the samples, whereas using acetone-aerosil treatment followed by adsorption with goose erythrocytes, the inhibitors were removed in 98.67% of the samples to a level that was undetectable at the 1:4 starting dilution in the HAI test.

Acetone↗
PubMed1991

The quantitation of rabies-specific antibodies. III. A comparative evaluation of modified counter immunoelectrophoresis, haemagglutination inhibition and serum neutralization titres of human sera.

The rabies-specific antibodies of 73 serum samples from vaccinated humans were determined by the modified counter immunoelectrophoresis (MCIE), and the haemagglutination inhibition test (HAI) by using the conventional serum neutralization test (SN) as a yard-stick. Both MCIE and HAI were found to be sensitive and specific for the estimation of rabies antibodies. In general, the unitages obtained by the MCIE and SN showed statistically insignificant differences (P greater than 0.05) and the correlation coefficient between the two methods was 0.697 (P less than 0.05). Although the unitage of the sera detected by HAI tests was lower by a factor of 0.155 from the unitage of SN tests, there was statistically insignificant differences between the two techniques (P greater than 0.05) with a correlation coefficient of 0.556 (P less than 0.05).

Antibodies, Viral↗
PubMed1991

Thermostability of Japanese encephalitis vaccine produced in India.

Different batches of bulk vaccine, final bulk at in-process level, finished freeze-dried and reconstituted Japanese encephalitis vaccine were assayed for their stability at temperatures of 22, 37 and 40 degrees C. After ultrazonal purification of 50 times concentrated brain suspension, JE Bulk vaccine was found to be stable for up to 2 years at 4 degrees C, however, the percentage loss in potency (log 10 N antibody titre) after 2.5 years was 24%. Three-times concentrated final bulk showed rapid deterioration by the fourth week at 37 and 40 degrees C. Freeze-dried JE vaccine maintained at 22 degrees C for 28 weeks did not show perceptible deterioration. At 37 degrees C, the same vaccine started showing deterioration (14%) after 8 weeks whereas at 40 degrees C the loss of potency was 24% after 8 weeks. The freeze-dried vaccine was found to be stable for up to 2 weeks duration at 40 degrees C.

Drug Stability↗
PubMed1991

Production of a safe, potent and immunogenic partially purified acellular pertussis vaccine using simple indigenous techniques.

Partially purified acellular pertussis vaccine was prepared from Bordetella pertussis strains 10536, 134, Tohama and 509 using simple indigenously available techniques. The Stainer-Scholte (SS) medium with methylated-beta-cyclodextrin was the most suitable for production of acellular pertussis vaccine. For preparation of the vaccine, 5 day cultures of B. pertussis grown under stationary conditions at 35 degrees C were treated twice with ammonium sulphate and prospective protective antigens were extracted. The extracts contained pertussis toxin (PT), filamentous hemagglutinin and agglutinogens. These extracts were treated with formaldehyde and glutaraldehyde separately for detoxification of PT. The formaldehyde treatment of acellular preparations affected the potency and did not destroy the toxic effects of PT completely. Active PT was found in formaldehyde detoxified acellular pertussis vaccine (FDAPV) preparations by the Chinese hamster ovary (CHO) cell assay, the test for leucocytosis promoting factor (LPF) and the histamine sensitization (HS) test. The FDAPV preparations did not pass the mouse weight gain test (MWGT). The glutaraldehyde treatment had lesser adverse effects on potency than the formaldehyde treatment and the glutaraldehyde detoxified preparations did not show active PT by CHO cell assay, the test for LPF and the HS test. The mice tolerated high doses (up to four human doses) of GDAPV which passed the MWGT showing higher weight gains. Both FDAPV and GDAPV showed immunogenicity against agglutinogens and PT in mice. The GDAPV is a safe and potent vaccine. The total protein content of GDAPV was about 5 times lesser than that of whole cell pertussis vaccine.

Adhesins, Bacterial↗
PubMed1991

Increasing prevalence of high degree resistance amongst Salmonella to different antibiotics.

National Salmonella & Escherichia Centre situated at Central Research Institute, Kasauli receives Salmonella strains from all over the country. Eight hundred and fourteen Salmonella strains belonging to 14 serotypes received during 1986 were studied for antibiotic resistance and Minimum Inhibitory concentration (MIC) with regard to ampicillin (A), chloramphenicol (C), furazolidone (Fz) and gentamicin (G). Resistance to ampicillin was found to be highest (80%) and furazolidone the least (0.1%). Similarly a large number of strains (31%) had very high MIC values greater than 640 mcg per ml for chloramphenicol, whereas only 3.4% strains were found to have MIC values greater than 640 mcg per ml for gentamicin. The present findings have been discussed in the light of similar data published from this Centre earlier and from other sources in India.

Ampicillin↗
PubMed1990

Immunogenicity of glutaraldehyde inactivated pertussis vaccine.

The immunogenicity of different types of glutaraldehyde inactivated pertussis vaccine (GIPV) preparations made by inactivation of Bordetella pertussis organisms with different concentrations of glutaraldehyde for variable periods at room temperature and conventional heat inactivated pertussis vaccine (HIPV) was evaluated with regard to production of agglutinins and neutralizing antibodies against pertussis toxin (PT). The different types of GIPV preparations had variable intracerebral mouse potency which depended upon the conditions of inactivation with glutaraldehyde. The agglutinin production in mice against various types of GIPV preparations and HIPV were very similar irrespective of the potency of the preparations. The agglutinins were produced against all the three major agglutinogens 1, 2 and 3 as the preparations were made from B. pertussis strain 10536 (serotype 1,2,3). The titres of agglutinins produced against adjuvanted preparations were slightly higher than those against non-adjuvanted preparations. Neutralizing antibodies against PT were produced for eight out of nine types of GIPV preparations while these antibodies were not produced for conventional HIPV.

Agglutination Tests↗
PubMed1990

Testing of adsorbed diphtheria-pertussis-tetanus (DPT) vaccine for freedom from abnormal toxicity.

A total of 112 samples of adsorbed DPT vaccine were tested in mice for freedom from abnormal toxicity by three procedures: (a) single human dose by intraperitoneal route; (2) single human dose by subcutaneous route; and (3) half the single human dose by intraperitoneal route. The percentage of samples passing by the three methods was 25, 90 and 54.5, respectively. Method 3, which is being recommended now by the World Health Organization, is supported by the results of this study to be neither very stringent nor very lenient to pass the adsorbed DPT vaccine for freedom from abnormal toxicity.

Animals↗
PubMed1990

Hemagglutination activities of purified pertussis toxin and filamentous hemagglutinin against erythrocytes from various animals.

The hemagglutinating (HA) activities of purified pertussis toxin (PT) and filamentous hemagglutinin (FHA) were evaluated against unfixed and glutaraldehyde-fixed erythrocytes from ox, goose, horse, monkey, sheep, chicken, and rabbit. Both PT and FHA showed HA activities against fixed and unfixed erythrocytes from all the animals studied. The HA titers of FHA were higher than those of PT. The HA activities of FHA and PT were not destroyed completely even after heating these preparations at 56 C for 30 min. A simple test for the assay of PT in culture supernatants of Bordetella pertussis on the basis of HA activity has been described.

Animals↗
PubMed1990

Mechanism of protection provided by active immunization with porins in mice challenged with Salmonella typhi.

Oxygen free radical (OFR) generation capacity of peritoneal macrophages was studied by chemiluminescent technique. Chemiluminescent (CL) response of macrophages from control, infected and immunized-infected mice was observed using non specific (Latex) and specific (S. typhi, cells and porins) stimulants at different time intervals. CL response was found to be significantly higher in immunized-infected group throughout the study period using all the three stimulants as compared to that in the infected as well as uninfected control mice. The mode of action of porin vaccine in increasing capacity of generating OFR is probably through increased expression of porin (protein) as well as carbohydrate receptors on the macrophage surface which leads to the stimulation of the whole caseade of respiratory burst or through the increase in the respiratory burst enzyme activities linked with each receptor or both.

Animals↗