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Biomedical subjects

P K Chattopadhyay

Publications and source records attributed to P K Chattopadhyay.

At least 19 recordsLinked to original sources
PubMed2006

Distribution of the F374 allele of the SLC45A2 (MATP) gene and founder-haplotype analysis.

The membrane-associated transporter protein (MATP) plays an important role in melanin synthesis. The L374F mutation in the SLC45A2 gene encoding MATP has been suggested to be associated with skin colour in major human populations. In this study more detailed distribution of the F374 allele was investigated in 1649 unrelated subjects from 13 Eurasian populations and one African population. The highest allele frequency was observed in Germans (0.965); French and Italians showed somewhat lower frequencies; and Turks had an intermediate value (0.615). Indians and Bangladeshis from South Asia were characterized by low frequencies (0.147 and 0.059, respectively). We also found the F374 allele in some East and Southeast Asian populations, and explained this by admixture. Haplotype analysis revealed that the haplotype diversity was much lower in Germans than in Japanese, and suggest that the L374F mutation occurred only once in the ancestry of Caucasians. The large differences in distribution of the F374 allele and its haplotypes suggest that this allele may be an important factor in hypopigmentation in Caucasian populations.

Antigens, Neoplasm↗
PubMed2005

Determination of the hand from single digit fingerprint: a study of whorls.

In this investigation 400 bilateral rolled fingerprints of Punjabi Jat males have been examined for the determination of the hand from single digit fingerprint from whorl patterns. Direction of the flow of the apex ridges, rotation of centrally circular ridges, angles between the core and the delta, ridge tracing, ridge counting and the position of the perpendiculars drawn between the delta and the core are useful for establishing in most of the cases the hand and finger involved from the fingers having whorl pattern.

Adolescent↗
PubMed2001

Reduced edge instability and improved confinement in the MST reversed-field pinch.

Improved confinement has been achieved in the MST through control of the poloidal electric field, but it is now known that the improvement has been limited by bursts of an edge-resonant instability. Through refined poloidal electric field control, plus control of the toroidal electric field, we have suppressed these bursts. This has led to a total beta of 15% and a reversed-field-pinch-record estimated energy confinement time of 10 ms, a tenfold increase over the standard value which for the first time substantially exceeds the confinement scaling that has characterized most reversed-field-pinch plasmas.

Journal Article↗
PubMed1983

Salivary agglutinins in an Indian population.

Saliva samples from 239 Punjabis have been analysed for the presence of anti-A and anti-B. Agglutinins have been found to be present in 35.98 per cent of the saliva samples studied. The amount of agglutinin present varies from one individual to another. Anti-A has been found to occur more frequently than anti-B among the Punjabis and most of the other populations studied so far.

ABO Blood-Group System↗
PubMed1980

Lysozyme production by a granuloma in vivo: output in blood and lymph in relation to ultrastructure and immunochemistry.

The output of lysozyme into the venous and lymphatic drainage of a B.C.G. experimental granuloma has been studied. There is a massive output of lysozyme by both routes maximal in the lymph at 28 days, and in the serum at 35 days after induction of the granuloma. There is no similar excretion of acid phosphatase. The lactic dehydrogenase level both in blood draining the granuloma and blood draining the normal limb is elevated but not in precise synchrony with lysozyme output. Macrophages in the granuloma show ultrastructural features suggestive of secretion of dense granules, by appearance of electron dense material in the Golgi zone, and condensation therefrom. Granules are discharged on to the surface of lipid droplets, presumably representing attempted phagocytosis, but are not discharged elsewhere on the cell surface. Granules are released by cell disintegration both of macrophages and polymorphs. Lysozyme was demonstrated immunocytochemically in macrophage granules. The macrophages in the granuloma are biosynthetically active as shown by uptake of tritiated tyrosine. The findings support the view that granulomas export lysozyme and that this is due partly to exocytosis of material by macrophages on to the surface of lipid globules and partly to cell disintegration.

Acid Phosphatase↗
PubMed1980

Enzyme content of hepatocellular lysosomes in the liver of the tumour-bearing mouse.

An increase in the number of hepatocellular lysosomes was not detected in mice bearing the solid or ascites forms of Sarcoma 180 or Ehrlich's tumour. Despite this, biochemical studies showed significant increases in acid phosphatase, cathepsin-D and beta-galactosidase. This difference between morphological and biochemical observations is explained by the fact that only gross increases in lysosome population are likely to be detected in the small samples examined with the electron microscope, but by biochemical methods whereby many grams of tissue are analysed finer changes may be detected. As far as is known at present there is an increase in hepatocellular lysosomes and/or lysosomal enzymes in tumour-bearing mice, rats and man and no exception to this exists.

Acid Phosphatase↗
PubMed1979

Incorporation of phosphatidylglycerol into murein lipoprotein in intact cells of Salmonella typhimurium by phospholipid vesicle fusion.

The biosynthesis of the diglyceride moiety of murein lipoprotein was studied by fusion of labeled phospholipid vesicles with intact cells of Salmonella typhimurium. Phosphatidylglycerol was found to be an excellent donor for the glyceryl moiety in lipoprotein, whereas phosphatidylethanolamine and cardiolipin were not. The incorporation of radioactivity from monoacyl-phosphatidylglycerol into lipoprotein can be attributed to its conversion to phosphatidylglycerol. The results strongly support our hypothesis that the glyceryl residue covalently linked to murein lipoprotein is derived from the nonacylated glycerol moiety of phosphatidylglycerol.

Bacterial Proteins↗
PubMed1979

Biosynthesis of murein lipoprotein in Escherichia coli: effects of 3,4-dihydroxybutyl-1-phosphonate.

The effects of 3,4-dihydroxybutyl-1-phosphonate, a four-carbon analog of sn-glycerol 3-phosphate, on the biosynthesis of the glyceryl moiety in murein lipoprotein of Escherichia coli were studied. The compound at a concentration of 55 microM strong inhibits in the incorporation of [2-3H]glycerol radioactivity into lipoprotein by virtue of its inhibition of the synthesis of phosphatidylglycerol. On the other hand, the incorporation of prelabeled [2-3H]glycerol radioactivity into lipoprotein was only partially inhbited by 3,4-dihydroxybutyl-1-phosphonate even at a much higher concentration (1 mM). These data were consistent with the postulated pathway for the biosynthesis of the lipid moiety in lipoportein: cysteine-lipoprotein + phosphatidylglycerol leads to glycerylcystein-lipoprotein + phosphatidic acid.

Bacterial Proteins↗
PubMed1979

Enzyme content of hepatocellular lysosomes in the tumour-bearing rat.

An increase in the number of hepatocellular lysosomes is detectable with the electron microscope in rats bearing a carcinogen-induced sarcoma but not in rats bearing a transplanted Walker tumour. Biochemical studies show an increase in lysosomal enzymes in the liver of both groups of rats, but the increase in the rats bearing a carcinogen-induced sarcoma was greater than that in rats bearing a Walker tumour. This difference is explained by the fact that only gross increases in lysosomal population are likely to be detected in the small samples examined with the electron microscope, but by biochemical methods whereby many grams of tissue are analysed, finer changes may be detected. The collective data to date indicate that an increase in hepatocellular lysosomes and/or lysosomal enzymes occurs in rats and man bearing a variety of tumours and to this there is, as yet, no known exception.

Acid Phosphatase↗
PubMed1977

Biosynthesis of the covalently linked diglyceride in murein lipoprotein of Escherichia coli.

Biosynthesis of the diglyceride moiety of murein lipoprotein in Escherichia coli was studied by pulse-labeling with [2-3H]glycerol and subsequent chase. The evidence strongly suggests that the precursor of the glycerol moiety in lipoprotein is one of the major phospholipid species in E. coli. Studies of biosynthesis of lipoprotein in cerulenin-treated cells indicated that the nonacylated glycerol moiety of phosphatidylglycerol is the donor for the formation of a thioether linkage in the glycerylcysteine residue of the lipoprotein. This is supported by the observation that carbon 1 rather than carbon 3 of sn-glycerol is involved in this thioether linkage. We propose that the biosynthesis of lipoprotein proceeds as follows: apolipoprotein + phosphatidylglycerol or acyl phosphatidylglycerol leads to lipoprotein + phosphatidic acid.

Apolipoproteins↗
PubMed1977

An anthropological study of the Malay and the Chinese of Malaysia.

Data for the ABO blood groups and for handclasping, arm folding, handedness, ear lobe types and camptodactyly are presented for 104 Malay and 57 Chinese males in the city of Alor Star, Kedah, Malaysia. The two groups exhibit marked differences in the frequencies of most of these attributes.

ABO Blood-Group System↗