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Biomedical subjects

K K Sharma

Publications and source records attributed to K K Sharma.

At least 109 records · Page 6Linked to original sources
PubMed1988

Vitamin A induced bilateral asymmetries in triturus forelimb regenerates.

After amputation of both forelimb of young, postmetamorphic Triturus alpestris through the middle of the zeugopod, the left and right regenerates grew asynchronously. As a result of oral administration of vitamin A palmitate (250 IU/gbw/day), from the 4th to the 13th dpa, the growth rate of the right regenerates was relatively higher than that of the left ones. Moreover, the percentage of skeletal abnormalities as well as proximodistal duplications (proximalizations), induced by vitamin A, was nearly twice as high in the right regenerates as compared to their left counterparts.

Aging↗
PubMed1987

The binding and inhibition of trypsin by alpha-crystallin.

One of the major lens-structural proteins, alpha-crystallin, is a multimeric protein containing 40 subunits of approx. 20 kDa each. There are two subunit types with distinct but similar structures. This protein was capable of inhibiting trypsin, chymotrypsin and elastase, but had no effect on thrombin or kallikrein. Complete inhibition was not observed, but rather plateau levels of inhibition were obtained in each case. Maximum inhibition was observed at a ratio of 1 mol of alpha-crystallin for every 9-10 mol of trypsin. alpha-Crystallin also inhibited the labeling of the active site of trypsin by [3H]diisopropyl fluorophosphate (DFP). Greater than 90% inhibition of DFP labeling was observed at a ratio of 1 mol of alpha-crystallin for every 7-8 mol of trypsin. Both trypsin and [3H]DFP-labeled trypsin formed a complex with alpha-crystallin, as demonstrated by gel-filtration chromatography. The active site of trypsin when bound to alpha-crystallin was still capable of reacting with p-nitrophenyl p-guanidobenzoate and soybean trypsin inhibitor, but was inaccessible to alpha 1-antitrypsin. These data suggest that alpha-crystallin acts as a multivalent modified inhibitor which is consistent with the proposed quaternary structure of alpha-crystallin.

Animals↗
PubMed1987

Purification and characterization of an aminopeptidase from bovine cornea.

An aminopeptidase from bovine cornea has been extensively purified by gel filtration and ion-exchange chromatography. The purified enzyme with a molecular weight of 96,000 showed broad substrate specificity. All of the various aminoacyl bonds were hydrolyzed optimally at pH 6.5. The purified enzyme showed hydrolytic activity towards bioactive peptides such as enkephalins, bradykinin, and angiotensin-II. The enzyme was inhibited by bestatin, amastatin, puromycin, bacitracin, sulfhydryl reagents and metal chelators. Only Co2+ stimulated the enzyme whereas other heavy metal ions were toxic. The gross properties of the corneal enzyme resemble those of an aminopeptidase III isolated from bovine lens.

Aminopeptidases↗
PubMed1986

Isolation and characterization of a new aminopeptidase from bovine lens.

An aminopeptidase has been purified to homogeneity from bovine lens tissue by gel filtration and DEAE-cellulose chromatography. This enzyme has a molecular weight of 96,000 under both native and denaturing conditions. The purified enzyme hydrolyzed a variety of synthetic substrates as well as di-, tri-, and higher molecular weight peptides. Significantly this enzyme is capable of hydrolyzing arginine, lysine, and proline aminoacyl bonds. The pH optimum for activity and stability was 6.0. Both a reduced sulfhydryl group and a divalent metal ion are essential for activity. The native enzyme contains 1.6 mol of zinc and 1.0 mol of copper/mol of enzyme. No activation was seen upon incubation with either magnesium or manganese; however, heavy metal ions were inhibitory. Bestatin and puromycin were effective inhibitors and no endopeptidase activity could be detected in the purified preparation. This enzyme is clearly distinct from the lens leucine aminopeptidase, but rather, is identical to a cytosolic aminopeptidase III isolated from other tissues. Evidence is presented which argues that this enzyme may be the major lens aminopeptidase under in vivo conditions.

Aminopeptidases↗
PubMed1986

Solubilization of the lens water-insoluble fraction by sonication.

A method is reported whereby the solubilization of the bulk of the lens water-insoluble fraction is accomplished by a short sonication of the suspended proteins in low salt buffers. This procedure solubilized greater than 90% of a bovine lens water-insoluble fraction and 80% of the normal human lens water-insoluble fraction. Decreased protein was solubilized from cataractous lenses, but in every case sonication was at least equivalent to extraction with 6.0 M urea. Fractionation of the solubilized proteins by Agarose A-1.5 m gel filtration chromatography showed native molecular weights for bovine lens, but only partial disaggregation with human lens extracts. A sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) comparison of the proteins solubilized by sonication and 6.0 M urea extraction showed no major differences except that sonication solubilized more of the highly cross-linked protein which remained at the top of the gel.

Adult↗
PubMed1986

An unusual foreign body in hand. A case report.

Small sharp foreign bodies are common in dominant hand. A case of an unusual, large, blunt, metallic foreign body in the non-dominant hand, with treatment and result, is reported.

Accidents, Occupational↗
PubMed1986

Aminopeptidase III activity in normal and cataractous lenses.

Aminopeptidase III activity was demonstrated in extracts from several different mammalian lenses by the hydrolysis of Arg-MCA at pH 6.0. No more than a two-fold difference was seen in overall specific activity. Sections of bovine lenses were removed from the periphery to the center and assayed. A sharp decline in activity was observed in the inner cortical region, and little or no activity was observed in the lens nucleus. This correlated with an increase in the presence of low molecular weight peptides as determined by SDS polyacrylamide gel electrophoresis. The properties of the aminopeptidase from human lens tissue were the same as those previously reported for the purified enzyme from bovine lens. The aminopeptidase activity of normal and cataractous lenses was compared using 4 different substrates. The cataractous lenses had significantly less total aminopeptidase activity. However, little difference in specific activity was observed based on soluble lens protein content. Similarly, electrophoretic separations of normal and cataractous soluble proteins showed little or no differences in the content of low molecular weight peptides. Therefore, this major human lens aminopeptidase remains functional in the cataractous state.

Aging↗
PubMed1985

The product of the regulatory gene of the proline catabolism gene cluster of Aspergillus nidulans is a positive-acting protein.

Eight new deletion mutations in the prn gene cluster involved in L-proline catabolism in Aspergillus nidulans have been characterised and mapped. Three of these are located within prnA, the regulatory gene mediating proline induction, and confirm the positive nature of the action of the prnA product. In addition, four prnA- alleles which are phenotypically suppressible by aminoglycoside antibiotics have been identified. Of these four phenotypically suppressible prnA- mutations, two have been tested for suppression by translational suppressors. Both are genotypically suppressible, showing that the prnA product must be a protein.

Aspergillus nidulans↗
PubMed1985

Nature of nonenzymatically bound hexose in hemoglobin, albumin, and crystallin.

Glucose incorporated in vitro during nonenzymatic glucosylation into albumin and hemoglobin was fully reducible by sodium borohydride unlike native albumin. Further, a prior hydrolysis under mild conditions (1 M oxalic acid:2 M HCl, 4 hr) was not required for in vitro incorporated glucose to yield maximal color intensity in the phenol-sulfuric acid reaction. Glucosyl-albumin, glucosyl-crystallin, and hemoglobin A1 behaved similarly in this respect. Hexose bound to HbA0 which alone showed an enhanced color intensity on prior acid hydrolysis was also not easily reduced by sodium borohydride. L-Cysteine (0.023 M) enhanced the color yield of glucosyl-hemoglobin, glucosyl-albumin, and glucosyl-crystallin to a lesser extent compared to fructose in the phenol-sulfuric acid reaction. Urea (6 M) also marginally increased the color intensity of glucosyl proteins and fructose.

Borohydrides↗
PubMed1983

Studies on sodium-borohydride-reducible hexose in glucosyl-albumin.

Glucosylated albumin of human serum isolated by dye-ligand chromatography on blue Sepharose, was not found to be completely reducible by sodium borohydride. The percentage reducible hexose as judged by phenol-sulphuric acid reaction was in the range of 49.7 +/- 12.8 in control subjects (n = 24) and 53.8 +/- 14.2 in diabetics (n = 50). Increase in the level of total hexose bound to albumin and reducible hexose were equally significant in diabetes (P less than 0.001). Sodium chloride gradient elution during chromatography on blue Sepharose showed that glucosylated albumin had lesser affinity than the native protein to the matrix. It is proposed that an addition product between hexose and albumin is formed during nonenzymatic reaction and this adduct is fairly stable and is not reducible by sodium borohydride.

Adult↗
PubMed1983

Leiomyoma of the palate.

Leiomyoma, a benign neoplasm of smooth muscle cell origin, has been documented infrequently in the oral cavity. It may arise wherever unstriated muscle is present including the arterial wall (Cherrick et al., 1973). The most common site is the uterus, followed by the wall of the alimentary canal and in subcutaneous tissue (McCaffrey et al., 1978). A search of the literature revealed 51 cases of oral leiomyomas. Cherrick et al. (1973) reviewed 35 cases, including seven of their own. Galili and Shteyer (1974) summarized the clinical data of 42 cases of oral leiomyomas reported since 1884. We can find only nine more reported cases of leiomyoma in the oral cavity: one each by Rhatigan and Kim (1976), Shirota et al. (1976), Kelly and Harrigan (1977), Schweigel (1980), Davis (1980) and Mechlin et al. (1980); and three cases by Damm and Neville (1979). The common sites in the oral cavity are the tongue and cheek but its occurrence on the palate is rare for out of the 51 cases of oral leiomyomas, only 10 involved the palate (one case each was reported by Fein, 1905; Kist and Bhaskar, 1964; Garrett, 1969; Galili and Shteyer, 1974; Rhatigan and Kim, 1976; and Davis, 1980; and four cases by Cherrick et al., 1973). Its rarity and large size make the tumour worth reporting.

Adult↗