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Biomedical subjects

H Kaur

Publications and source records attributed to H Kaur.

At least 91 records · Page 5Linked to original sources
PubMed1995

Importance of dynamic assessment of the soft tissues in the sonographic diagnosis of echogenic superficial abscesses.

Superficial abscesses evaluated by ultrasonography may occasionally be isoechoic relative to the surrounding inflamed tissues and without mass effect, preventing diagnosis by morphologic criteria alone. We present a simple and effective method to detect such abscesses. In three cases, gentle repetitive pressure of the inflamed tissue revealed the liquefied nature of abscesses that otherwise would have been overlooked.

Abscess↗
PubMed1995

Ascaris and Trichuris do not contribute to growth retardation in primary school children.

To access the effectiveness of the treatment of soil-transmitted helminthiasis (STH) on the growth of primary school children, 353 children were block stratified to receive either mebendazole plus pyrantel oxantel pamoate every three months or a placebo. The children were followed for two years with 89% completing the trial. Follow-up stools indicated that the treatment was efficacious for ascariasis and trichuriasis. There was virtually no hookworm infection. The children were malnourished as measured by the number below -2 SD of height and weight standards. There was no difference in height or weight between the treatment and control groups by sex initially or at the end of two years of follow-up. The treatment of Ascaris and Trichuris had no effect on growth parameters. The effect of STH on growth may be mediated through hookworm infections.

Ascariasis↗
PubMed1995

Predictive utility of clinical and stool parameters in bacterial diarrhoea in children.

A prospective one year study was conducted on children between the ages of 1 month to 5 years hospitalised in the pediatric ward of Christian Medical College, Ludhiana, with the aim of determining the predictive utility of certain clinical and stool parameters in diagnosing bacterial diarrhoea. Among the 204 children enrolled in the study, fever was observed in 40% in both the culture positive and negative groups. Clinical features such as abdominal distension, vomiting and oliguria although had low positive predictive values, their negative predictive values were high. Among the stool parameters, watery consistency and pus cells > 5 HPF were significantly more often observed in culture positive cases. The presence of mucus and pus cells > 5 HPF had good sensitivity (70-80%) but poor specificity (27-40%), while the reverse was true of blood (sensitivity 23%, specificity 89%). Again the positive predictive values were uniformly low while the negative ones were high. In conclusion the clinical and stool parameters were found to be more useful by their absence than by their presence in excluding a positive stool culture.

Bacterial Infections↗
PubMed1994

Intense oxidative DNA damage promoted by L-dopa and its metabolites. Implications for neurodegenerative disease.

Oxidative DNA damage can cause mutation and cell death. We show that L-DOPA, dopamine and 3-O-methyl-DOPA cause extensive oxidative DNA damage in the presence of H2O2 and traces of copper ions. 8-Hydroxyguanine is the major product. Iron ions were much less effective and manganese ions did not catalyse DNA damage. We propose that copper ion release, in the presence of L-DOPA and its metabolites, may be an important mechanism of neurotoxicity, e.g. in Parkinson's disease and amyotrophic lateral sclerosis.

Brain Chemistry↗
PubMed1994

Interactions of peroxynitrite with human plasma and its constituents: oxidative damage and antioxidant depletion.

Endothelial cells and activated phagocytes produce both nitric oxide (.NO) and superoxide (O2.-), which react to form peroxynitrite. Peroxynitrite has been suggested to be directly cytotoxic and also to decompose into other toxic species. In order to understand the consequences of peroxynitrite generation in vivo, we examined its reaction with human blood plasma. Peroxynitrite decreased the total peroxyl-trapping capacity of plasma. In terms of specific antioxidants, addition of peroxynitrite to plasma leads to rapid oxidation of ascorbic acid, uric acid and plasma SH groups. The oxidation of plasma SH groups was enhanced in dialysed plasma and returned to control levels by the addition of physiological levels of bicarbonate. Evidence was found for formation of nitro-adducts to aromatic side chains in plasma proteins by peroxynitrite. Peroxynitrite also leads to depletion of ubiquinol and formation of traces of lipid hydroperoxides in plasma, although alpha-tocopherol levels were only slightly decreased. Peroxynitrite formation in human body fluids is likely to cause antioxidant depletion and oxidative damage.

Antioxidants↗
PubMed1994

Evidence for nitric oxide-mediated oxidative damage in chronic inflammation. Nitrotyrosine in serum and synovial fluid from rheumatoid patients.

Reaction of nitric oxide (NO.) with superoxide radical generates peroxy-nitrite, which can decompose to products that nitrate aromatic amino acids. Such nitro-aromatics may be 'markers' of NO.-dependent oxidative damage. Blood serum and synovial fluid from patients with the inflammatory joint disease rheumatoid arthritis contain 3-nitrotyrosine. By contrast, body fluids from normal subjects and patients with osteoarthritis contain no detectable 3-nitrotyrosine; much lower levels were found in serum from patients in the early stages of rheumatoid arthritis. This is evidence that NO. plays a role in joint damage in rheumatoid arthritis.

Arthritis, Rheumatoid↗
PubMed1994

Aromatic hydroxylation and nitration of phenylalanine and tyrosine by peroxynitrite. Evidence for hydroxyl radical production from peroxynitrite.

Peroxynitrite is a highly reactive species, generated from superoxide and nitric oxide. Some effects of peroxynitrite are ascribed to the molecule itself, but decomposition products of the protonated form, peroxynitrous acid, may account for much of its reactivity in biological systems. Suggested products include highly-reactive hydroxyl radicals, but thermodynamic calculations have been used to claim that free hydroxyl radicals cannot be formed from peroxynitrite. We utilized aromatic hydroxylation of phenylalanine as a specific detector of hydroxyl radicals, and found that incubation of phenylalanine with peroxynitrite leads to a small amount of p-, m- and o-tyrosine, specific products of attack by this radical. Products of nitration of phenylalanine and tyrosine were also detected, as was dityrosine. Peroxynitrite decomposition generates several reactive species, including some that can nitrate aromatic rings. Formation of nitro-aromatic compounds may be a useful marker of peroxynitrite generation in biological systems.

Hydroxyl Radical↗
PubMed1994

Aromatic hydroxylation of phenylalanine as an assay for hydroxyl radicals. Measurement of hydroxyl radical formation from ozone and in blood from premature babies using improved HPLC methodology.

Highly reactive hydroxyl radicals (OH.) attack the amino acid phenylalanine to give ortho-, meta-, and para-tyrosines. An improved HPLC-based separation of these products is described. Both D- and L-phenylalanine are attacked by OH., although only the latter is a substrate for the enzyme phenylalanine hydroxylase. Use of this improved aromatic hydroxylation assay to detect OH. is illustrated by measuring OH. in ozonized aqueous solutions at pH 7.4, and by showing that blood from some premature babies appears to be capable of catalyzing OH. formation.

Catalysis↗
PubMed1994

Acute respiratory infection in Malaysian children.

A cross-sectional community-based survey was conducted to determine the prevalence of acute respiratory infection (ARI) in children below 7 years of age and to obtain baseline information for an intervention programme. A total of 6190 households comprising 38,632 persons with 12,273 children (32 per cent) below 7 years of age were surveyed. Information on socio-demographic variables, environmental sanitation, occurrence of ARI and diarrhoea, treatment seeking behaviour during episodes of those illnesses and immunizations among children were obtained. Thirty per cent of children had experienced ARI in the 2-week period prior to the interview, and 94 per cent had mild ARI, 1 per cent had moderate and 5 per cent had severe ARI. There was lack of concurrence between mother's perception of severity and that of the investigators' (Kappa coefficient = 0.083 (95 per cent CI = 0.017-0.149). Twenty-four and 39 per cent of severe and moderate ARI, respectively, were reported by mothers to be mild. There is cause for concern as these children may not receive timely and appropriate treatment. The findings from this study contribute to identification of target populations and priority areas for health education of the population. The survey has provided useful baseline data for the implementation of an intervention programme for the control of ARI in children.

Acute Disease↗
PubMed1994

Social problems of women leprosy patients--a study conducted at 2 urban leprosy centres in Delhi.

Leprosy seems to afflict women less commonly than men, but for cultural reasons this difference may be more apparent than real. Unfortunately, the effects are as equally devastating, if not more so, in women than in men. This study, carried out at the Urban Leprosy Centres of Safdarjung Hospital and Dr Ram Manohar Lohia Hospital in Delhi, showed that the impact of stigmata attached to leprosy had more effect on educated women belonging to a higher socioeconomic group than on less fortunate women. Discriminative attitudes were more common in joint than nuclear families. Although many got support from their families, the disease had definite psychological effects. Because of the fear of infecting the family members, women sufferers kept themselves aloof and were constantly worried about divorce. Fear of social ostracism prevented the disclosure of disease to the community. Deformities and disabilities led to a deterioration in their functional capabilities and their psychological state of mind. Pregnancy did not affect regularity of treatment. Many women needed an escort to attend the clinic. Solutions to minimize some problems have been suggested.

Adolescent↗
PubMed1994

Correlation between phospholipid biosynthesis and intracellular levels of cyclic adenosine monophosphate in Mycobacterium smegmatis.

The influence of intracellular levels of cAMP on phospholipid synthesis in Mycobacterium smegmatis has been examined under conditions of varying carbon source. A decreased phospholipid content was observed in glucose-grown cells, possibly due to decrease in intracellular cAMP levels caused by decreased/increased activity of adenylate cyclase and phosphodiesterase, respectively. The lowered phospholipid content was supported by decrease both in [14C]acetate incorporation and activities of key enzymes of phospholipid biosynthesis. These results in the light of our earlier observation of enhanced phospholipid synthesis in presence of increased levels of cAMP suggest a direct correlation between phospholipid biosynthesis and intracellular levels of cAMP in M. smegmatis.

Cyclic AMP↗
PubMed1994

Composite carcinoid carcinoma of the colon--a case report.

A composite tumour of the caecum and colon, comprising of distinct areas of classical carcinoid and of well differentiated adenocarcinoma is described. Both components were histochemically confirmed. Presence of a morphologic transition at junctional areas favour a histogenesis from bi-directional differentiation of multipotent precursor cells.

Adenocarcinoma, Mucinous↗
PubMed1993

Combined multidrug and Mycobacterium w vaccine therapy in patients with multibacillary leprosy.

Immunotherapy with Mycobacterium w vaccine was attempted in patients with borderline-borderline, borderline lepromatous (BL), or lepromatous leprosy (LL) to determine whether immunization can hasten recovery and reduce treatment time by invigorating cell-mediated immunity. Mycobacterium w, a nonpathogenic, rapidly growing, atypical mycobacterium, shares a number of common B and T cell determinants with Mycobacterium leprae and Mycobacterium tuberculosis. Patients receiving the vaccine had rapid clinical improvement and accelerated bacteriologic clearance. After treatment with vaccine for 2 years, 13 of 31 BL and LL patients were bacteriologically negative as were 5 of 25 controls. Vaccinated patients had one of two distinct histologic features, either an upgrading in the disease spectrum or complete clearance of granuloma. Some 80% of lepromin conversions were in BL and LL patients who received vaccine versus none and 14.3% of BL and LL controls, respectively. Thirteen of 17 vaccinated LL patients were released from treatment after 2 years in contrast to 2 of 15 controls.

Bacterial Vaccines↗
PubMed1993

Use of aromatic hydroxylation of phenylalanine to measure production of hydroxyl radicals after myocardial ischemia in vivo. Direct evidence for a pathogenetic role of the hydroxyl radical in myocardial stunning.

A pathogenetic role of .OH in myocardial stunning has been inferred from the protective effects of .OH scavengers and iron chelators. However, conclusive demonstration of the .OH radical hypothesis of myocardial stunning requires direct verification of three major, but still unproven, assumptions: (1) .OH is produced in the stunned myocardium in vivo; (2) antioxidant therapy inhibits .OH production; and (3) such inhibition results in enhanced recovery of contractility (ie, .OH is necessary for the development of myocardial stunning). Since phenylalanine (Phe) reacts with .OH to form the hydroxylated products ortho-, meta-, and para-tyrosines (o-, m-, and p-tyr), we used aromatic hydroxylation of Phe to detect .OH formation in the stunned myocardium. Open-chest dogs undergoing a 15-minute coronary occlusion followed by reperfusion received an intravenous infusion of Phe (54.3 mg/kg for 11.5 minutes beginning 90 seconds before reperfusion); these animals were given either no antioxidant therapy (group I, n = 15), N-2-mercaptopropionyl glycine (MPG) (group II, n = 11), or MPG combined with superoxide dismutase, catalase, and desferrioxamine (group III, n = 12). In addition, group IV (nonischemic control group, n = 6) received Phe but did not undergo coronary occlusion, whereas group V (ischemic control group, n = 16) underwent a 15-minute occlusion but did not receive Phe or antioxidants. The plasma concentrations of tyrosines in the local venous effluent and in the arterial blood were measured with high-performance liquid chromatography. In group I, production of o- and m-tyr, which are specific markers of .OH formation, began during coronary occlusion but increased dramatically immediately after reperfusion, peaking at 1 minute and continuing up to 10 minutes of reperfusion. In group II, the production of o- and m-tyr was markedly decreased throughout the first 10 minutes of reperfusion. In group III, the production of m-tyr was decreased to levels similar to those in group II, whereas the production of o-tyr was almost completely abolished. There was no appreciable production of o- or m-tyr in group IV. Recovery of contractile function (assessed as systolic wall thickening) was increased in group I vs group V. Recovery of function was further enhanced in group II, with only a slight additional improvement in group III.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1993

Oxidation of biologic molecules by ozone: the effect of pH.

Ozone (O3) is a powerfully oxidizing pollutant gas. Its toxic effects to animals appear to be worsened by coexposures to acid-generating compounds such as oxides of nitrogen and sulfur. Ozone (16 ppm) oxidizes ascorbic acid and uric acid (two important antioxidants in lung lining fluids) at equal rates at pH 5.0 or pH 7.4. Loss of intrinsic fluorescence and formation of carbonyls in albumin exposed to O3 are similar at both pH values. However, albumin-SH groups are lost much faster on exposure to O3 at pH 7.4 than at acidic pH values. A similar slower rate of -SH group disappearance at acidic pH is seen when cysteine or reduced glutathione are exposed to O3. We suggest that the ability of reduced glutathione, albumin, and other proteins containing -SH groups to scavenge O3 in the respiratory tract is impaired at low pH and that this effect could contribute to the aggravation of O3 toxicity.

Albumins↗
PubMed1992

Oxidative damage to plasma constituents by ozone.

The reaction of ozone (O3) with human blood plasma was studied to help understand possible events that could occur in the respiratory tract. Uric acid (quantitatively the most important scavenger) and ascorbic acid were oxidized quickly, protein-SH groups were lost more slowly, and there was no loss of bilirubin or alpha-tocopherol. There was little formation of lipid hydroperoxides and no detectable formation of 4-hydroxynoneal, hexanal or nonanal, or changes in lipoprotein electrophoretic mobility. Uric acid in human upper airway secretions may play a significant role in removing inhaled O3. Oxidative damage to lipids must not be assumed to be the key mechanism of respiratory tract O3 toxicity.

Adult↗