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Biomedical subjects

A Gupta

Publications and source records attributed to A Gupta.

At least 937 records · Page 52Linked to original sources
PubMed1983

Fuchs' heterochromic cyclitis: some observations on clinical picture and on cataract surgery.

In a study of 33 patients of heterochromic cyclitis, some unusual clinical features were observed. In many cases the iris was feltlike, month eaten, and associated with gelatinous nodules at the pupillary border or over the surface of iris stroma. An association of pseudoexfoliation of the lens capsule with bilateral heterochromic cyclitis was noted. Twenty-one eyes were subjected to cataract surgery. Hyphema (23.6%) and phacoanaphylactic uveitis (9.5%) were the main postoperative complications.

Adolescent↗
PubMed1983

Umbilical hernia.

Explore the source record for details and available documents.

Hernia, Umbilical↗
PubMed1982

Purification and properties of protein methylase II from wheat germ.

Protein methylase II (S-adenosylmethionine: protein-carboxyl O-methyltransferase, EC 2.1.1.24) was purified from wheat germ approximately 1200-fold with a yield of 4.6% by employing gel filtration. The enzyme, using S-adenosyl-L-methionine, methyl-esterifies the free carboxyl group of protein. Since the enzymatic product was unstable and hydrolyzed non-enzymatically to yield methanol, methanol was identified from the hydrolysate by the formation of the methyl ester of 3.5-dinitrobenzoate. The pH optimum for the wheat germ enzyme was 7.0 in contrast to the 6.0 for the methylase II of calf brain. The wheat germ enzyme had a molecular weight of 41 000 compared to 25 000 for the corresponding rat erythrocyte enzyme [S. Kim (1975) Arch. Biochem. Biophys. 161, 652-657]. The enzyme also differed with the mammalian enzyme in protein substrate preference: the mammalian enzyme showed equal preference to histone and immunoglobulin G while the wheat germ enzyme transferred a methyl group 4.5 times more to histone than to immunoglobulin G. The Km values for histone and S-adenosyl-L-methionine were 0.2 mM and 5 microM. S-Adenosyl-L-homocysteine and its analogues, sinefungin and A9145C, were competitive inhibitors with Ki values 1.5 microM, 0.4 microM and 0.1 microM, respectively. To investigate the identity of endogenous substrate(s) for protein methylase II, the crude wheat germ extract was incubated with S-adenosyl-L-[methyl-3H]methionine and the methylated proteins were analyzed by acid/urea and sodium dodecyl sulfate/polyacrylamide gel electrophoresis. Among other methyl acceptors in the wheat germ, histone polypeptides were the major endogenous substrates.

Kinetics↗
PubMed1982

Template-prime-dependent turnover of (Sp)-dATP alpha S by T4 DNA polymerase. The stereochemistry of the associated 3' goes to 5'-exonuclease.

T4 DNA polymerase converts (Sp)-2'-deoxyadenosine 5'-O-(1-thio[1-18O2]triphosphate) to 2'-deoxyadenosine 5'-O-[18O]-phosphorothioate in the presence of poly(d(A-T).poly(d(A-T)) template-primer. Control experiments involving either omitting the poly(d(A-T)).poly(d(A-T) template-primer or employing the (Rp)-2'-deoxyadenosine 5'-O-(1-thiotriphosphate) diastereomer showed no reaction. It is assumed, therefore, that this conversion as in the P--O case involves incorporation of the thionucleotide into the poly(d(A-T)) followed by hydrolysis resulting from the 3' goes to 5'-exonuclease activity. The 2'-deoxyadenosine 5'-O-[18O] phosphorothioate was converted to (Sp)-2'-deoxyadenosine 5'-O-(1-thio[1-18O]triphosphate), with no change in the configuration at P alpha by using the coupled adenylate kinase-pyruvate kinase enzyme system. A 31P NMR spectrum of the product showed that the 18O was entirely in the nonbridging position, indicating an overall retention in the net turnover process (i.e. incorporation followed by excision). Since the incorporation process involves an inversion of configuration around the phosphorus (Romaniuk, P. J., and Eckstein, F. (1982) J. Biol. Chem. 257, 7684-7688), it must be inferred that the 3' goes to 5'-exonuclease activity of T4 polymerase proceeds with inversion of configuration at the phosphorus atom, most simply via a direct displacement mechanism. This finding represents the first example of phosphodiester hydrolysis catalyzed by an exonuclease that does not involve a covalent phosphoryl-enzyme intermediate (Knowles, J. R. (1980) Annu. Rev. Biochem. 49, 877-919).

DNA-Directed DNA Polymerase↗
PubMed1982

Histopathological changes in different tissues of T. fasciatus under the acute impact of BHC.

The acute toxic effect of BHC on gills, liver, stomach and intestine of a fresh water teleost, Trichogaster fasciatus, has shown pathological changes after exposure to a sublethal (1.5 ppm) and a lethal (3.6 ppm) concentration of the toxicant for 24 and 96 h. Damage to the different tissues was more pronounced in a lethal concentration of the chemical and increased time of treatment. The gills exhibited greater damage compared with the liver, stomach and intestine. Swelling of the secondary lamellae leading to the detachment of the epithelium from the pillar-cell system (PS) and its partial degeneration with loss of rigidity of the PS and hypertrophy in the lamellar channels were the major changes induced. In the liver, the tissue showed prominent splitting (SP) due to the widening of the sinusoids. The cells lost their shape, the membrane was ruptured, the cytoplasm became granulated and necrosis was evident. Degeneration of the epithelium (EP), shrinkage and atrophy in the tunica propria (TUP) and vacuolation (VA) in different layers of the stomach and intestine were also observed.

Animals↗
PubMed1982

Early onset of presbyopia.

Of the 800 presbyopes studied, 286 (35.75%) entered presbyopia at or before the age of 38 years. About 63% of these patients lived in rural areas and 37% in urban areas. Environmental conditions including high average temperature, much ultraviolet radiation, chronic deficiency of essential amino acids, and exposure to toxic factors, particularly hair dye, may play a significant role in precipitating the early onset of presbyopia.

Adult↗