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Biomedical subjects

K K Sharma

Publications and source records attributed to K K Sharma.

At least 73 records · Page 4Linked to original sources
PubMed1997

Forensic analysis and psycholegal implications of parricide and attempted parricide.

In a retrospective archive study, 64 adjudicated adult cases involving the murder or attempted murder of at least one parent, referred for forensic evaluations are described. Biographic, demographic, diagnostic, crime scene, psycholoegal opinion, and disposition data are presented. Results indicated a 40% rate of insanity acquitees. Attempted parricide subjects were more likely to have inpatient psychiatric histories, witnesses present during the criminal act, nonresponsiveness towards their actions, competency raised, and a hospital disposition. Gender and ethnicity were found to have a significant effect on ultimate disposition. Fifty-four percent of the sample opined psychotic were sentenced to prison, suggesting other factors considered by judge and jury. Profile characteristics and typologies are presented. The findings are compared to studies involving parricide and legal strategies involving similar cases.

Adolescent↗
PubMed1996

Identification of new lens protease(s) using peptide substrates having in vivo cleavage sites.

Bovine lens extracts were incubated in pH 7.5 buffer with succinylated VSREEKPSSAPSS, SGVDAGHS, GKPTSAPSS and GKHNERQD, the peptides having age-dependent in vivo cleavage sites in bovine and human alpha A-crystallin. The reaction products were analyzed to identify the initial protease cleavage sites. The results showed that bovine lens extracts contain protease activity that can cleave. Thr-Ser, Ser-Ala, Ser-Ser bonds in test substrates which correspond to peptide bonds Ser168-Ser169, Ser169-Ala170, Ser172-Ser173 in bovine alpha A-crystallin and Thr-Ser, Ser169-Ala170, Ser172-Ser173 in human alpha A-crystallin. In addition, the same extracts were also capable of hydrolyzing Asp-Ala and Asn-Glu bonds corresponding to Asp151-Ala152 and Asn101-Glu102 in alpha A-crystallin from bovine and human lenses. The cleavage specificity of the newly discovered protease(s) suggests that the in vivo truncation of alpha A-crystallin reported earlier may be due to the action of proteases. The newly discovered lens protease(s) were resistant to inactivation by E-64 and DFP. However, prior treatment of the lens extracts with leupeptin and chymostatin resulted in partial loss of Asn-Glu hydrolytic activity. N-ethylmaleimide treatment completely abolished in the Asn-Glu hydrolyzing activity.

Amino Acid Sequence↗
PubMed1996

Peptide hydrolysis in lens: role of leucine aminopeptidase, aminopeptidase III, prolyloligopeptidase and acylpeptidehydrolase.

The distribution of leucine aminopeptidase, aminopeptidase III, prolyloligopeptidase and acylpeptidehydrolase activities in different regions of a bovine lens was determined and correlated with the distribution of crystallin fragments (measured as < 18 kDa protein) and water-insoluble proteins in the same lens. A gradient of activity was observed for all the peptidases tested, with the highest specific activity present in the cortical fibers which decreased to one half or below in the inner cortical fibers and nucleus. An inverse correlation between peptidase activities and the amount of crystallin fragments was observed in different regions of the lens. However, a direct correlation between the water-insoluble protein content and the crystallin fragments was observed in all fibers of the same lens. The amount of crystallin fragments and the amount of water-insoluble proteins increased from 2.7% and 8% in the outer cortical fibers to 13% and 68% in the nucleus of the same lens. The water-insoluble fraction from both cortical and nuclear fibers however displayed 4-5 fold more crystallin fragments compared to that present in the water-soluble fraction of the same preparation. When the bovine lens cortical and nuclear extracts were tested for their ability to hydrolyze the peptide substrate, Ile-Ser-bradykinin, the cortical extract was found to be at least ten times superior to the nuclear extract. Prior inactivation of prolyloligopeptidase and other serine proteases by diisopropylfluorophosphate however diminished the ability of the cortical extract to hydrolyze peptide substrates. Bovine lens cortical extract was able to completely hydrolyze alpha-melanocyte stimulating hormone as well as N-Acetyl-Met-Asp-Arg-Val-Leu-Ser-Arg-Tyr showing the presence of active acylpeptidehydrolase facilitating the complete hydrolysis of N-terminally blocked peptides. The human lens extract was found to contain both diisopropylfluorophosphate sensitive and resistant enzymes capable of hydrolyzing peptide substrates.

Amino Acid Sequence↗
PubMed1996

Comparison of leucine aminopeptidase and aminopeptidase III activities in lens.

PURPOSE: To evaluate the relative contribution of leucine aminopeptidase and aminopeptidase III activities to the total aminopeptidase activity in bovine and human lenses under in vivo pH conditions. METHODS: Bovine and human lens extracts were fractionated on a Sephadex G-200 column at pH 6.9 and 8.5 and all the fractions were assayed with Leu-pNA and Arg-pNA as substrates at in vivo lens pH (6.9) and optimum pH for leucine aminopeptidase, (8. 5). The major peptidases were purified and their activities compared with that of LAP and AP III isolated from bovine lens. The ability of bovine and human lens extracts and purified bovine lens LAP and AP III to hydrolyze various peptide bonds in synthetic peptides, VHLPTVEK, bradykinin and Ile-Ser-bradykinin was determined by amino acid analysis of the reaction products. RESULTS: Sephadex G-200 gel chromatography and assay of all the fractions at pH 6.9 showed that the elution volume for the predominant aminopeptidase present in bovine lens extract is the same as that of purified AP III from the same lenses. However, when the assays were done at pH 8.5, the major activity eluting from the Sephadex G-200 column was found in fractions having LAP. A similar study of human lens extracts at pH 6. 9 and 8.5 showed one major peak with elution volume corresponding to that of purified bovine lens AP III: The human lens extracts displayed a very low level of LAP activity. The hydrolysis pattern of peptide substrates by AP III paralleled that of bovine and human lens extract at pH 6.9. The X-Pro bond resistant to LAP in peptide substrate, VHLTPVEK was hydrolyzed by AP III as well as lens extracts. CONCLUSION: Both bovine and human lenses have very low LAP activity compared to AP III activity at in vivo pH 6.9. AP III, by its higher activity, broad specificity and its ability to cleave peptide bonds that are resistant to LAP, is likely to play a major role in lens during epithelial cell differentiation into fiber cells and complete hydrolysis of peptides generated in vivo.

Amino Acid Sequence↗
PubMed1995

Effect of cross-linking on the chaperone-like function of alpha crystallin.

Alpha crystallin can function as a molecular chaperone in suppressing the heat-induced aggregation of other crystallins and proteins. During cataractogenesis, alpha-crystallin becomes a water-insoluble, high-molecular-weight, cross-linked aggregate. To determine whether the chaperone activity of alpha crystallin is lost during this age-related modification, extracts were prepared by sonication of water-insoluble proteins isolated from aged bovine lenses and human cataract lenses. All the preparations were tested for chaperone-like activity using beta L-crystallin as the target protein and the percentage of alpha-crystallin in water-insoluble sonicated supernatant (WISS) was determined by slot blot immunoassay. The WISS from bovine as well as human lenses were still effective in protecting beta L-crystallin aggregation at 56 degrees C. The bovine cortical WISS with 50% immunoreactive alpha-crystallin showed 62% of the chaperone-like activity displayed by native alpha-crystallin. The WISS from bovine lens nucleus and human lenses with 17% and 5% immunoreactive alpha-crystallin showed 19% and 4% chaperone-like activity compared to native alpha-crystallin. Prior treatment of the WISS of both bovine and human lenses with dithiothreitol resulted in nearly 50% increase in chaperone-like activity suggesting possible loss of chaperone-like activity due to disulfide cross-links. To see if the chaperone-like activity of alpha-crystallin can be altered by non-disulfide cross-linking, native alpha-crystallin isolated from bovine lenses was cross-linked with dimethylsuberimidate (DMS) and dimethyl 3,3'-dithiobispropionimidate (DTBP) and tested for chaperone-like activity. The DMS cross-linked alpha-crystallin was effective in inhibiting the aggregation of beta L-crystallins at 56 degrees C, but required a two- to five-fold higher concentration than the native alpha-crystallin. alpha-Crystallin with higher degree of cross-linking showed lower chaperone-like activity. alpha-Crystallin cross-linked with DTBP, a cleavable cross-linking agent, also showed a 80% loss in chaperone-like activity. However, when the DTBP cross-linked alpha-crystallin was treated with dithiothreitol to cleave the cross-links there was a 50% recovery in the chaperone-like activity. These data suggest that the age-related cross-linking, which restricts the molecular flexibility of alpha-crystallin decreases its chaperone-like function.

Aged↗
PubMed1995

A double-blind randomized placebo cross-over controlled trial using the antioxidant vitamin E to treat reactive oxygen species associated male infertility.

OBJECTIVE: To determine the effectiveness of the in vivo administration of vitamin E as treatment for reactive oxygen species-associated male infertility. SETTING: University-based center for reproductive medicine. DESIGN: Double-blind randomized placebo cross-over controlled trial. PATIENTS, PARTICIPANTS: Thirty healthy men with high levels of reactive oxygen species generation in semen and a normal female partner. INTERVENTIONS: Patients were allocated to two groups according to the blinded randomization. Each patient received either 600 mg/d of vitamin E (Ephynal, 300 mg tablets; F. Hoffman-La Roche Ltd., Basle, Switzerland) (order A) or identical placebo tablets (order B) for 3 months. Then after a 1-month wash-out period the patients were crossed-over to the other treatment. MAIN OUTCOME MEASURES: Improvement in the in vitro function of the spermatozoa measured by conventional semen analysis, computerized motility assessment, determination of reactive oxygen species generation, binding to the zona pellucida of the unfertilized human oocyte in a competitive zona binding assay, development of hyperactivated motility (both spontaneous and in the presence of 20% of the natural agonist, human follicular fluid) and pregnancy. RESULTS: Rise in the blood serum vitamin E levels after treatment accompanied by improvement in one of the sperm function tests: the zona binding assay. The zona binding ratio for order A improved from 0.2 (range 0 to 0.5) before treatment to 0.5 (range 0.1 to 1.0) after treatment, the corresponding values for order B were 0.2 (range 0 to 1.0) before treatment and 0.3 (range 0.1 to 0.7) after treatment. CONCLUSION: Oral administration of vitamin E significantly improves the in vitro function of human spermatozoa as assessed by the zona binding test.

Adult↗
PubMed1995

Oral steroid therapy for subfertile males with antisperm antibodies in the semen: prediction of the responders.

This study was performed to examine the effectiveness of steroid therapy in subfertile men with antisperm antibodies and infertility lasting > 1 year, to predict those who would respond positively, and to evaluate the effect of the therapy on semen parameters and antisperm antibodies. The patients included 48 subfertile couples in whom the male partner had > or = 20% motile spermatozoa with bound antibodies of immunoglobulin (Ig)G, IgA or a combination of both, and were treated with prednisolone, 40 mg a day, for the first 10 days, then 5 mg on days 11 and 12 of the partner's cycle for 9 months. Twelve couples became pregnant; a cumulative conception rate of 30.2% was achieved at 9 months. The pregnant group started with significantly higher concentrations of IgG (tail) and grade I motility (P = 0.03 and P = 0.02 respectively). Multi-covariate discrete logistic regression analysis on the initial screening semen samples predicted a higher chance of conception for those with high levels of IgG (tail) (P = 0.006, sensitivity = 33%, specificity = 93%, correct = 75%, false positive = 33% and false negative = 24%). In the pregnant group, prednisolone caused a significant increase in grade I motility (P = 0.03). In the non-pregnant group, there was a significant increase in grade I motility (P = 0.0002), amplitude of lateral head displacement (P = 0.03), curvilinear velocity (P = 0.02) and decrease in grade IV motility (P = 0.03) following prednisolone treatment. In both groups there was suppression of the total antisperm antibody concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1995

Elevation in diacylglycerol level and activation of protein kinase C in liver of mice administered with carcinogenic dose of 1,2-dimethylhydrazine.

Five weeks treatment of male mice with 1,2-dimethylhydrazine leads to elevation in the level of diacylglycerol in liver. Increase in diacylglycerol content is accompanied by an increase in particulate activity of protein kinase C with a fall in its activity in cytosolic fraction. Quantitative analysis of neutral lipids of different subcellular fractions from liver reveals that diacylglycerol levels increases highly significantly in liver microsomal membranes of carcinogen treated mice. Separation of neutral lipids by thin layer chromatography indicates that also there is an increase in cholesterol esters in nuclei, mitochondria and microsomes of mice liver whereas monoacylglycerol almost disappeared in mitochondria and microsomes after DMH administration in comparison to their respective controls.

1,2-Dimethylhydrazine↗
PubMed1994

Purification and characterization of prolyl oligopeptidase from bovine lens.

Prolyl oligopeptidase (EC 3.4.21.26) has been purified 26,000-fold from bovine lens tissue by anion-exchange chromatography, gel filtration and isoelectric focussing, with an overall yield of 11%. The purified enzyme exhibited an isoelectric point of 4.8, a pH optimum of 7.5 and a molecular mass of 72 kDa under both native and denaturing conditions. The enzyme was inhibited by diisopropylfluorophosphate and N-ethylmaleimide, indicating the presence of an essential serine residue and an -SH group. The purified enzyme hydrolyzes the elastase substrate tboc-ala-ala-pNA an order of magnitude more rapidly than N-suc-gly-pro-MCA. It also hydrolyzes other elastase substrates including N-suc-ala-ala-ala-pNA, N-suc-ala-ala-pNA, N-suc-ala-ala-pro-ala-pNA and tboc-ala-ala-pro-ala-pNA, but at a slower rate. While the purified preparation of the lens enzyme rapidly hydrolyses bradykinin, ile-ser-bradykinin, insulin B chain, angiotensin and val-his-leu-thr-pro-val-glu-lys at the carboxyl side of proline, it does not hydrolyse either lens crysallins or bovine serum albumin. The amino acid sequence (GMFYNAYPQQDG) of a tryptic peptide from the enzyme is identical to the porcine brain prolyl oligopeptidase sequence 184-195. A similar activity has been identified in human lenses using both tboc-ala-ala-pNA and N-suc-gly-pro-MCA as substrates. The molecular weight, substrate specificity, inhibitor susceptibility and amino acid sequence data suggest that the bovine lens prolyl oligopeptidase is similar to prolyl endopeptidase isolated from other sources.

Amino Acid Sequence↗
PubMed1994

Delusional misidentification syndromes and dangerousness.

Dangerousness in the delusional misidentification syndromes is studied by reviewing a sample of 82 cases defined by either verbal threats or physical violence caused by misidentification delusion. Eighty cases were obtained from a review of the anglophone psychiatric literature in which the patients exhibited some degree of dangerousness, to which we added 2 previously unreported cases.

Adult↗
PubMed1994

A comparison of the inhibition of porcine pancreatic elastase and human neutrophil elastase by alpha-crystallin.

Bovine lens alpha-crystallin inhibited both porcine pancreatic elastase (PPE) and human neutrophil elastase (HNE), but not in the same manner. PPE was immediately inhibited with a stoichiometry of 10 moles of PPE inhibited per mole of alpha-crystallin. The inhibition was markedly decreased by the addition of even low levels of salts. The inhibition was transient, as PPE activity returned to normal with a t1/2 of 30 min even in low salt. HNE required a short preincubation to show maximum inhibition with a stoichiometry of approximately one mole of HNE inhibited per mole of alpha-crystallin. The inhibition of HNE was only slightly decreased by the addition of 0.1 M salt, and HNE activity returned slowly exhibiting a t1/2 of 30 hrs under these conditions. The inhibition of each enzyme by alpha-crystallin was evaluated by Dixon plots giving Ki values of 1.5 nM for PPE and 0.25 nM for HNE. DFP-trypsin was able to compete with PPE for binding to alpha-crystallin and cause the release of PPE already bound to alpha-crystallin. The inhibition of HNE, however, was unaffected by the addition of DFP-trypsin. A mixture of HNE and alpha-crystallin in 0.1 M NaCl was incubated at 25 degrees C for 6 hours. Aliquots showed a slow, continuous cleavage of the alpha-crystallin subunits by SDS-PAGE, but little or no increase in HNE activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Bovine lens acylpeptide hydrolase. Purification and characterization of a tetrameric enzyme resistant to urea denaturation and proteolytic inactivation.

An acylpeptide hydrolase has been purified from bovine lens tissue by anion-exchange and hydrophobic-interaction chromatography. The enzyme, purified over 27000-fold with 44% recovery, has a molecular mass of 300 kDa under native conditions. Under denaturing conditions it shows a subunit molecular mass of 75 kDa. The enzyme is inhibited by diisopropylfluorophosphate (iPr2P-F), phenylmethylsulfonyl fluoride and N-ethylmaleimide, indicating the presence of an essential serine residue and -SH group. Each subunit of the enzyme has one active serine residue which can be labelled with [3H]iPr2P-F. N alpha-blocked amino acids in L form act as competitive inhibitors of the enzyme. The antibiotics penicillin-G and ampicillin partially inhibit the enzyme. Exposure of the purified enzyme to the proteases trypsin, chymotrypsin or elastase do not result in any loss of activity. Digestion of the native enzyme with bovine trypsin generates a 55-kDa protein containing the active-site serine and a 22-kDa polypeptide, indicating the presence of a unique trypsin site. N-terminal amino acid sequencing of the 55-kDa polypeptide shows that the bovine lens enzyme has a sequence at the trypsin cleavage site identical to the porcine liver acylpeptide hydrolase sequence 196-215. The data show that the split enzyme is as active as the native enzyme towards the synthetic substrate Ac-Ala-p-nitroanilide. The enzyme activity decreases with increasing urea, but 15% of the activity remains even in the presence of 6.0 M urea. On removal of urea, complete recovery of the enzyme activity is observed. However, treatment with 1 M guanidine/HCl completely inactivates the enzyme.

Amino Acid Sequence↗
PubMed1993

Chemical modification of alpha crystallin.

Calf lens alpha-crystallin was isolated and the lysine residues were extensively modified with a variety of chemical agents. The effect of these modifications on elastase inhibitor activity, apparent molecular size, antibody reactivity and solubility were determined. The addition of either a methyl group or a threose residue did not alter the charge on the lysine residues and had little or no effect on either inhibitor activity or apparent molecular size. The introduction of a negative charge by either carboxymethylation or citraconylation caused a marked decrease in size and an almost complete loss of inhibitor activity. The introduction of a hydrophobic residue by reaction with either a trinitrobenzenesulfonic acid or Bolton Hunter reagent caused a slight increase in size, but a 70% increase in elastase inhibitor activity. Reaction with fluorescamine resulted in the dissociation of alpha-crystallin in a 200-kDa species, yet caused a two to four-fold increase in elastase inhibitor activity, which was similar to the activity of the water-insoluble fraction isolated from aged human lens and cataract. Several of these modified alpha-crystallins were compared for reactivity with a polyclonal alpha-crystallin antiserum using a quantitative slot blot assay. Charge neutral modifications resulted in a two to three-fold loss of antibody recognition, whereas the other preparations showed an almost complete loss of antigenic activity. None of the modifications caused the alpha-crystallin to precipitate at higher salt concentrations (0.3 M) with the exception of threose which caused a 30% decrease in soluble protein.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Treatment of theileriosis in crossbred cattle in the Punjab.

One hundred and nine cases of bovine tropical theileriosis (Theileria annulata infection) in Punjab State, India, were treated with oxytetracycline (23 cases) or buparvaquone (86 cases). Ages of affected cattle ranged from 6 days to 3 years. Oxytetracycline cured only 7 animals (30.4%), all of them calves below 15 days old, while buparvaquone cured all but one (98.8%), a severely affected 10 day old calf. Cured cattle remained theileriosis-free for 12 to 18 months following recovery. Theileriosis in Punjab is predominantly a disease of young calves that cannot be protected by available cell-culture vaccines. It is suggested that the most economical way to control theileriosis in India would be to immunise calves by infection with sporozoite stabilate and simultaneous treatment with tetracycline, and to reserve buparvaquone for the treatment of clinical cases, in cattle of all ages.

Age Factors↗
PubMed1993

Nephrolithiasis in children.

A study of 100 cases of nephrolithiasis between 3 to 15 years of age is reported. Seventy four cases were more than 10 years old. The common presenting symptoms included abdominal pain (69%), burning micturition (23%), gross hematuria (4%) and unexplained pyrexia (6%). Associated urinary tract malformations were found in 16 cases. Twenty four had struvite calculi. Urinary infection with Proteus mirabilis was found in 23 children and idiopathic hypercalciuria in 31 cases. Following surgical removal, either percutaneously or by open surgery, 8 patients had residual calculi and in 6 cases recurrence occurred.

Adolescent↗
PubMed1993

A comparative study of erotomanic and obsessional subjects in a forensic sample.

Erotomania is the delusional belief that one is passionately loved by another. These persons often go to great lengths to approach their object of desire, often necessitating the attention of the law. We have reviewed a forensic sample to select subjects who meet criteria for the diagnosis of erotomania. Case histories from all of the case files of the Threat Management Unit of the Los Angeles Police Department were reviewed to compare erotomanic subjects with those who were suffering from other disorders. Various demographic and other relevant data were examined to determine if the erotomanic subjects presented similar or different profiles.

Adult↗