Search PubMed⌕ Search

Biomedical subjects

R Kumar

Publications and source records attributed to R Kumar.

At least 253 records · Page 14Linked to original sources
PubMed1993

Enteroaggregative Escherichia coli may be a new pathogen causing acute and persistent diarrhea.

The role of Hep-2 cell adherent Escherichia coli (EAEC) of localized (EAEC-L), diffuse (EAEC-D) and aggregative (EAggEC) phenotype, was investigated in 254 children aged < or = 48 months seeking treatment for non-bloody diarrhea at an outpatient clinic, and in 107 age-matched controls. The stool excretion rates of single isolates from patients/controls for the different phenotypes of Hep-2 cell adherent E. coli were: EAEC-L, 5.9/2.8%, p = 0.33; EAEC-D, 7.5/12.1%, p = 0.22; and EAggEC, 11.8/3.7%, p = 0.03. When patients were categorized by pre-admission diarrheal duration > or = 14/< 14 days, the excretion rates were EAEC-L, 0/7.1%; EAEC-D, 9.5/7.1%, and EAggEC, 21.4/9.9%, the difference approaching significance only for EAggEC (p = 0.06). These findings suggest that EAggEC may be an important cause of diarrhea in children, with a predilection to cause prolonged disease.

Acute Disease↗
PubMed1993

The tyramine test is not a marker for postnatal depression: early postpartum euphoria may be.

Abnormally low tyramine test values are known to be markers for vulnerability to unipolar, but not bipolar, endogenous depression. In the present study, 37 women with recent postnatal depression (25 major, 12 minor) and 22 puerperal controls with no depressive disorder, all assessed by Schedule for Affective Disorder and Schizophrenia (SADS-L) interview, together with 17 other controls, underwent the test. No significant differences in tyramine sulfate output were demonstrated between the different groups. Those subjects with endogenous features according to Newcastle score (n = 7) or Research Diagnostic Criteria (RDC) (n = 6) also had normal output. Thus, the tyramine test does not appear to be a useful marker for vulnerability to postnatal depression. Over half the subjects recalled that their postnatal depression had started in the first 2 weeks postpartum. Of the total of 62 postpartum subjects interviewed with the SADS-L, ten recalled a period of euphoria in the first postpartum week, which met RDC for hypomania and eight of them went on to become depressed postnatally. An additional patient from the total group was hospitalized with mania.

Adult↗
PubMed1993

Incidence of fungal infection in extra hepatic biliary stone disease.

50 patients undergoing biliary surgery were studied to know the incidence of fungal infection. Samples such as bile & stones for mycological analysis were obtained from the gall bladder & Common Bile Duct (CBD) at the time of surgery. Fungal aetiology was established in 8 (16.3%) cases. Incidence of fungal infection was more (12.2%) in gall bladder bile as compared to 6% in common bile duct bile. The nucleus of stone yielded growth of fungus in only 2 (4.6%) cases. Candida albicans, C. tropicalies, C, kruzei, Penicillium and Aspergillus were the common fungal isolates in the present study.

Aspergillosis↗
PubMed1993

Altered maternal thyroid function: fetal and neonatal heart cholesterol and phospholipids.

The influence of maternal thyroid function on the fetal and neonatal myocardial cholesterol and phospholipid content was studied in rats. Fetuses born to hyperthyroid mothers had decreased total cholesterol and increased esterified cholesterol while offsprings born to hypothyroid mothers had increased total, free and esterified cholesterol during late gestation and/or at term. Phospholipid fractions phosphatidyl choline and phosphatidyl ethanolamine in offsprings born to hyperthyroid mothers were not significantly changed. Offsprings born to hypothyroid mothers had decreased total phospholipids, phosphatidyl choline and phosphatidyl ethanolamine at fetal and neonatal stages. 3H-acetate incorporation in phosphatidyl choline and phosphatidyl ethanolamine was also decreased. Maternal thyroid seems to have important role in the regulation of cholesterol and phospholipid metabolism in fetal and neonatal hearts.

Acetates↗
PubMed1993

Incidence of salmonella meningitis in Ludhiana (Punjab).

A retrospective study was carried out at Dayanand Medical College & Hospital, Ludhiana (Pb.) during the period from January 1985 to December 1990 to know the incidence of Salmonella meningitis. Salmonella etiology was established in 8 (3.43%) cases out of 233 cases of bacterial meningitis. Out of 8 cases, 7 were children under the age of 2 years. 4 Patients yielded S. typhimurium, 3, S. typhi and 1 S. senftenberg from cerebrospinal fluid samples. No Salmonella organism was isolated from blood cultures except one in which S. typhi was isolated. S. typhimurium was the predominant isolate showing multi drug resistance to commonly used drugs such as ampicillin, chloramphenicol, streptomycin, tetracycline and kanamycin. S. senftenberg also showed similar drug resistance pattern. S. typhi, on the other hand was sensitive to above antibiotics.

Aged↗
PubMed1993

Multi drug resistant Salmonella typhi in Ludhiana (Punjab).

280 Salmonella typhi strains isolated from suspected cases of enteric fever during the year 1990 were studied for susceptibility to the antimicrobial agents chloramphenicol, ampicillin, cotrimoxazole, gentamycin, kanamycin, amikacin, ciprofloxacin by Kirby Baur disc diffusion method. All were blood culture positive cases. 63 strains (21.9%) were found resistant to chloramphenicol, ampicillin, cotrimoxazole, but sensitive to the amino glycosides and ciprofloxacin. Present study shows the prevalence of multi drug resistant Salmonella typhi in this region of Punjab.

Adult↗
PubMed1993

Clinical sequelae of Japanese encephalitis in children.

Over a five and a half year period, virological investigations for Japanese encephalitis (JE) were conducted in children admitted with acute encephalitis like illness to a large city hospital. The diagnosis of Japanese encephalitis was made by viral isolation from cerebrospinal fluid and/or a four-fold or higher rise in haemagglutination inhibiting antibodies in paired sera followed by demonstration of specific IgM antibodies by HI test after treatment with 2-mercapto ethanol. All children surviving the illness were contacted by post and followed up for sequelae. A total of 55 children could be followed up after 12-18 months and 22 of these even after 2 yr. A high rate of major sequelae (45.5%) in the form of frank motor deficits (32.7%), mental retardation (21.8%) and/or convulsions (18.2%) was observed. Neurological deficits were of diverse types and improved even after 2 yr of the illness. Fourteen patients (25.4%) had only minor deficits in the form of scholastic backwardness, behavioural problems and/or subtle neurological signs. Only 16 (29.2%) patients were completely normal on follow up. JE may therefore be an important cause of neurological handicap in this area. Sequelae of the disease were more severe if the initial illness was prolonged (P < 0.001, CI 2.45, 12.64), or associated with focal neurological deficits (P < 0.001, CI 1.97, 7.02).

Child↗
PubMed1993

Streamlined records benefit maternal and child health care.

In order to simplify the collection, recording and reporting of information on maternal and child health care in a rural area of India, a home-based mother and child card and a tally sheet were introduced. This has made it possible for the community to evaluate the services provided.

Child Health Services↗
PubMed1993

Production of human hemoglobin in transgenic swine: an approach to a blood substitute.

Many significant challenges have to be met before a clinically useful hemoglobin-based blood substitute can be developed. A major issue is the choice of a production system. Transgenic swine have several features that appear to be suited to the abundant production of human hemoglobin. Here we show that authentic human hemoglobin can be made in transgenic pigs and purified by simple ion-exchange chromatography. The purified hemoglobin can be modified for testing and use as a blood substitute.

Animals↗
PubMed1992

The expression of milligram amounts of functional human 1,25-dihydroxyvitamin D3 receptor in a bacterial expression system.

We expressed milligram amounts of functional human 1,25-dihydroxyvitamin D3 receptor in a bacterial expression system in which the cloned cDNA for the hVDR was expressed under the control of bacterial T7 polymerase. The hVDR protein comprised approximately 60% of total bacterial protein. It migrated on polyacrylamide-sodium dodecyl sulfate gels with an M(r) of 48,000. It had the predicted amino acid composition and amino acid sequence analysis. The expressed protein was bound by 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) with a Kd in the nanomolar range. It sedimented on sucrose density gradients at 3.5S. Furthermore, the expressed protein bound to the osteocalcin vitamin D response element (VDRE) as assessed by a gel mobility shift assay. The expression of large amounts of hVDR protein should allow for the use of this protein in structure-function and x-ray crystallography studies.

Amino Acid Sequence↗
PubMed1992

Equal inhibition of HIV replication by stereoisomers of phosphatidyl-azidothymidine. Lack of stereospecificity of lysosomal phospholipase A1.

Glycerol-1-P and glycerol-3-P stereoisomers of dipalmitoylphosphatidylazidothymidine were synthesized and found to have equal antiretroviral activity in HIV-infected HT4-6C cells. It was anticipated that the glycerol-1-P isomer would be less active because of slow metabolic conversion by cellular phospholipases A and C, but the antiretroviral results suggested that the human cell line (HT4-6C) may have phospholipases capable of hydrolyzing 2,3-dipalmitoyl-sn-glycerol-1-phospho-5'-azidothymidine (AZT). To evaluate this possibility, we purified lysosomal phospholipase A1, an enzyme known to play a major role in cellular phospholipid catabolism. This enzyme rapidly hydrolyzed both the sn-1 and sn-3 isomers of dipalmitoylphosphatidyl-AZT. We synthesized sn-2,3-dipalmitoyl-glycero-1-phosphocholine and found that it is also hydrolyzed readily by lysosomal phospholipase A1 although the Vmax, 59 mumol mg-1 h-1, is slightly lower than that of the sn-1,2-dipalmitoyl-glycero-3-phosphocholine, 89 mumol mg-1 h-1. In conclusion, our studies show that sn-2,3-dipalmitoyl-glycerol-1-phospho-AZT is equal in antiviral activity to sn-1,2-dipalmitoyl-glycero-3-phospho-AZT in HIV-infected HT4-6C cells. This surprising result is due in part to the lack of stereospecificity of lysosomal phospholipase A1.

Animals↗
PubMed1992

Effect of dietary nitrate on endogenous nitrosation of piperazine in humans.

The effect of dietary nitrate on endogenous nitrosation of a therapeutic dose of piperazine has been described in five human volunteers who acted as their own controls. The urinary excretion of endogenously formed N-nitro-somonopiperazine (MNPz) ranged between 9.2 and 80.1 micrograms/24 h on a normal uncontrolled diet which increased from 25.7 to 163.7 micrograms/24 h when the diet was supplemented with 250 mg nitrate. The corresponding urinary nitrate was 63.0-122.7 mg/24 h and 119.2-322.0 mg/24 h, respectively. The dinitroso derivative of piperazine was detected only in trace amounts and no detectable increase in its excretion was observed during high nitrate exposure. The unchanged piperazine (range 294-784 mg/24 h) in urine showed a decrease under high nitrate regimen (range 185-399 mg/24 h).

Carcinogens↗
PubMed1992

Interferon alpha induces the expression of retinoblastoma gene product in human Burkitt lymphoma Daudi cells: role in growth regulation.

Interferon alpha (IFN-alpha) is a regulatory secretory protein with distinctive biological effects such as antiproliferative actions against many tumor cell lines, including human Burkitt lymphoma Daudi cells. The mechanism underlying growth inhibition by IFN-alpha is not well established. The growth of many mammalian cell types is also regulated by tumor suppressor retinoblastoma (RB) gene product, the RB protein. In the studies presented here, we explored the possible involvement of RB protein in the growth inhibitory action of IFN-alpha in the Daudi cell model system. We observed that IFN-alpha induces a 3- to 10-fold increased expression of RB protein in growth-sensitive Daudi cells but not in the growth-resistant variant of Daudi cells. IFN-alpha-mediated induction of RB protein was an early event that preceded the period of growth inhibition of Daudi cells. IFN-alpha-induced RB protein predominantly exists as the underphosphorylated form. Addition of antibody against IFN-alpha to Daudi cells resulted in the inhibition of constitutive expression of RB protein and stimulation of [3H]thymidine incorporation. These results demonstrate that the induction of RB protein expression in IFN-alpha-treated Daudi cells could constitute an important mechanism of IFN-alpha-mediated growth regulation.

Burkitt Lymphoma↗
PubMed1992

Growth regulation of human renal carcinoma cells: role of transforming growth factor alpha.

Findings of increased numbers of epidermal growth factor receptors (EGF-R) and increased expression of transforming growth factor alpha (TGF-alpha) in surgical specimens of human renal cell carcinoma have led to the proposal that growth of these tumors may be regulated by TGF-alpha in an autocrine manner. In the studies presented here, we have examined this hypothesis using two human renal carcinoma cell lines, SKRC-4 and SKRC-29. We demonstrated that both SKRC-4 and SKRC-29 cells were growth stimulated by greater than 35% when cultured in the presence of TGF-alpha or EGF and were inhibited by 29% to 46% if cultured in the presence of anti-EGF-R monoclonal antibody 225. Treatment of cells with TGF-alpha enhanced the levels of expression of EGF-R mRNA and TGF-alpha mRNA. In addition, incubation of cells with monoclonal antibody 225 significantly elevated the levels of excreted TGF-alpha species in the culture medium. Our findings suggest that proliferation of human renal carcinoma cells may be regulated by endogenously produced TGF-alpha and that this regulatory pathway can be interrupted using antibody to its receptor, EGF-R.

Carcinoma, Renal Cell↗