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Biomedical subjects

S R Das

Publications and source records attributed to S R Das.

At least 55 records · Page 3Linked to original sources
PubMed1980

A large-scale radiometric micro-quantitative complement fixation test for serum antibody titration.

A micro-quantitative complement fixation (CF) procedure based on 51Cr release is described. The method employs 50% hemolysis as end point and the alternation equation to calculate the amount of complement involved in the hemolytic reaction. Compared to the conventional CF tests, the radiometric procedure described here is very precise and consistently reproducible. Also, since only 3 4-fold dilutions of sera are used for the titration of antibodies over a wide range of concentrations, the test is very concise and is economical to perform. Its format is amenable to automation and computerization. This radiometric CF procedure is thus most useful for large-scale immunological research and epidemiological surveillance studies.

Animals↗
PubMed1979

Structure and synthesis of naturally occurring anhydrovitamin A2.

The structure of naturally occurring anhydrovitamin A2 was elucidated as 3-hydroxyanhydroretinol from study of its u.v.--visible, i.r., n.m.r. and mass spectra. The structure has been confirmed by a chemical synthesis. Saccobranchus fossils, a freshwater fish, can convert 3-hydroxyretinol into 3-hydroxyanhydroretinol, which in turn is converted into-3-dehydroretinol. Chemical conversion of 3-hydroxyretinol into 3-dehydroretinol was also carried out.

Animals↗
PubMed1976

Restoration of virulence to rat of axenically grown Entamoeba histolytica by cholesterol and hamster liver passage.

A virulent strain of Entamoeba histolytica (NIH-200) from a symptomatic human case, cultured in vitro for more than three years, was unable to infect rat caecum or hamster liver. When grown with a mixed bacterial flora, it infected rat caecum but did not produce ulceration. After passaging amoebae growing with bacteria in hamster liver, amoebic hepatic lesions were regularly produced. The amoebae from liver lesions produced ulceration in the caeca of rats. Expoxure to cholesterol of amoebae growing with bacteria or feeding rats orally with cholesterol and injecting these amoebae along with bacteria also led to the production of ulcers in rats. Thus virulent amoebae which have been cultured in vitro for a long time become attenuated but their virulence can be revived.

Animals↗
PubMed1975

The effect of parity on placental weight and birth weight: interaction with placental alkaline phosphatase polymorphism.

The effect of parity on placental weight and birth weight is examined through a series of birth records from an Indian population in Calcutta. Placental weight and birth weight increase with parity, the maximum increment occurring between parities 1 and 2. This is compatible with a hypothesis of sensitization of the mother to foetal, paternally derived, antigens. The three common placental alkaline phosphatase enzymic genotypes have no effect on determining foetal development.

Adult↗
PubMed1975

Proportion with low birth weight infants in an Indian population and its relationship with maternal age and parity.

The overall proportion of low birth weight infants is found to be relatively higher in the Indian population. Data collected from two hospitals in Calcutta, India indicate that although the proportion of infants weighing less than 2,001 g is approximately 10%, the dependence of this proportion on maternal age and parity is similar to the studies conducted elsewhere, suggesting a definite biological significance of the phenomenon. The proportion of low birth weight infants is found to be the greatest for the first and late pregnancies, the minimum being at the third birth rank. Young mothers showed a tendency to have an increasing proportion of low birth weight infants with increasing birth order; whereas for older mothers a general U-shaped dependence of the proportion on parity is suggest from the analysis.

Adolescent↗