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Biomedical subjects

R Kumar

Publications and source records attributed to R Kumar.

At least 217 records · Page 12Linked to original sources
PubMed1991

Do children with severe head injury benefit from intensive care?

Intensive management of severe closed head injury is pursued in most neurosurgical units, as it no doubt reduces mortality. However, the fate of those salvaged from death is less clearly defined. The impact of aggressive management on the psychological recovery is even less clear. This retrospective study of children admitted to a regional paediatric neurosurgical service attempts to address these issues. Eighty-four children between the ages of 3 to 16 years with severe head injuries were studied and categorized according to conservative or intensive treatment groups. The availability of intensive management led to a greater number of such children referred. The mortality in those children sustaining more severe injury, i.e. Glasgow Coma Score (GCS) 3 or 4, was halved (44%) with intensive management from 80% in the conservative group. For those with less severe injury (GCS 5-8), it was unchanged at about 23%. The reduced mortality is at the expense of increased morbidity. Psychological testing showed that the cognitive recovery was comparable.

Adolescent↗
PubMed1991

Immunohistochemical localization of a calcium pump and calbindin-D28k in the oviduct of the laying hen.

The localization of a plasma membrane calcium pump in the oviduct of the laying hen was investigated by immunohistochemical techniques, utilizing a monoclonal antibody (5F10) produced against the human erythrocyte calcium pump. This antibody was shown to react with an epitope of the pump in oviductal tissue, and prominent staining was observed on the microvilli of the tubular gland cells of the hen shell gland (uterus) and the isthmus. The Ca2+ pump was not detectable in the infundibulum or the magnum. Calbindin-D28k, also localized by immunohistochemical means, was observed to be present in the tubular gland cells of the shell gland and the distal isthmus (adjacent to shell gland) but not in either the proximal isthmus (adjacent to the magnum), the magnum or the infundibulum. The localization of the Ca2+ pump in the oviduct corresponds to known sites of mineral deposition during egg shell formation. The distribution of calbindin-D28k differed, co-localizing with the Ca2+ pump in the shell gland and distal isthmus but not in the proximal isthmus. This might reflect a greater rate of active Ca2+ secretion in the distal isthmus and shell gland as compared to the proximal isthmus.

Animals↗
PubMed1991

Expression of virulence and antibiotic resistance in an Escherichia coli transconjugant carrying a large plasmid pCAT120 of Shigella dysenteriae type I and its spontaneous fragmentations.

The role of a 120-kb plasmid in relation to virulence and drug resistance factor in Shigella dysenteriae was studied. For characterization of plasmids, the mating system is a useful and efficient means of transferring both large and small plasmids to a new host. The conjugative transfer of a 120-kb (pCAT120) ampicillin-resistant plasmid of S. dysenteriae to E. coli K-12 was not successful. Introduction of an E. coli fertility factor plasmid F, did not help to mobilize the plasmid. Low transfer frequencies of antibiotic markers to E. coli were achieved by treatment of the donor S. dysenteriae with N-methyl-N'-nitro-N-nitrosoguanidine. The transconjugants showed resistance to ampicillin, chloramphenicol, tetracycline and cadmium. A transconjugant carrying the 120-kb plasmid of S. dysenteriae produced keratoconjunctivitis in guinea pigs. Repeated subculture of Clmr transconjugant (pCAT120) on tryptic soya agar plates became Clms and showed four distinct DNA bands ranging from 3 to 10 kb in size on agarose gel electrophoresis. Utilization of organic acids, metal resistance (Cd), dye-binding properties (Crb+, Ebr+) and drug resistance (Amp, Tet) were identified on 10, 7, 4 and 3-kb plasmid DNA fragment of pCAT120 respectively. Crb+ 4-kb DNA fragment of pCAT120 was isolated, purified and transferred to an avirulent E. coli K12 by transformation. However, transformant (pET4) showed poor growth on solid media and its growth in liquid culture was only possible after supplementation of the unknown low-molar-mass thermolabile factor(s) secreted by the recipient strain.(ABSTRACT TRUNCATED AT 250 WORDS)

Bacterial Outer Membrane Proteins↗
PubMed1991

Presence of embryotoxic factor in the sera of neonates affected by myelomeningocele: a study on chick embryo.

An experimental study on chick embryos was conducted where 0.02 mL of serum, taken from five neonates (1 to 7 days of age) with myelomeningocele was injected separately into the fertile white leghorn eggs, at zero hour of incubation. A total of 150 experimental and 135 control eggs were injected. It was observed that the embryos of chick exposed to experimental serum had an increased frequency of embryonic death and/or gross abnormalities as compared with the control group (chi 2 = 32.07; P less than .001). The anomalies observed were those of neural tube, gastrointestinal system, and musculoskeletal system. In addition, there was a generalized growth retardation among experimental embryos. These malformations are probably due to an embryotoxic factor, which is present in the serum of the baby with myelomeningocele and has been transmitted transplacentally.

Animals↗
PubMed1991

Tobacco-specific N-nitrosamines in tobacco and mainstream smoke of Indian cigarettes.

Different brands of Indian cigarettes were analysed, by gas chromatography-thermal energy analysis, for the presence of carcinogenic tobacco-specific N-nitrosamines (TSNA) in both tobacco and mainstream smoke. Preformed TSNA in cigarette tobacco ranged between 68 and 730 ng N-nitrosonornicotine (NNN)/cigarette, between 19 and 174 ng 4-(N-nitrosomethylamino)-1-(3-pyridyl)-1-butanone (NNK)/cigarette and between 98 and 519 ng N-nitrosoanabasine (NAB) together with N-nitrosoanatabine (NAT)/cigarette. The amounts of NNN, NNK and NAB/NAT in mainstream smoke were 11-156, 7-73 and 17-146 ng/cigarette, respectively.

Chromatography, Gas↗
PubMed1991

The presence of platelet-activating factor-like activity in human spermatozoa.

Evidence is provided for the existence of platelet-activating factor (PAF)-like activity in the lipid extracts of human spermatozoa. The PAF content of human spermatozoa based on [3H]-serotonin release from washed rabbit platelets was noted to be 1.45 pmol/10(8) sperm cells in highly purified motile spermatozoa. No PAF activity was associated with the seminal fluid. Platelet-activating factor content of spermatozoa may be related to its fertility potential.

Animals↗
PubMed1991

Endogenous formation of N-nitrosamines from piperazine and their urinary excretion following antihelmintic treatment with piperazine citrate.

Antihelmintic treatment with piperazine (1,4-diazacyclohexane) for microfilarie parasitism results in the endogenous formation of piperazine-derived N-nitrosamines. The urinary excretion of these N-nitrosamines was determined by biochemical monitoring of 14 patients receiving 2 g piperazine citrate. The urinary excretion (mean +/- SD) of N-mononitrosopiperazine (MNPz) was 27.0 +/- 26.7 micrograms/day (range 0.6-96.0 micrograms/day). Trace levels of 0.73 +/- 0.92 micrograms/day N,N'-dinitrosopiperazine (DNPz) (range ND-2.8 micrograms/day) were also found in 7 of 14 urine samples. N-Nitroso-3-hydroxypyrrolidine (NHPYR), a metabolite of both MNPz and DNPz, was detected in 11 of 14 urine samples at a mean concentration of 1.74 +/- 1.72 micrograms/day (range ND-5.7 micrograms/day) and traces of N-nitrosodiethanolamine in two samples at levels of 0.3 and less than 0.1 micrograms/day. The results show that biochemical monitoring of urinary NHPYR may be a good indicator of endogenous MNPz formation. While DNPz was also detected in urine, conclusive validation for its endogenous formation could not be provided because no evidence was found for the presence of its major metabolite, N-nitroso-(2-hydroxyethyl)glycine in urine.

Adult↗
PubMed1991

Perceptual dysfunction in hemiplegia and automobile driving.

Sixteen post-stroke, hemiplegic patients, who requested that they be allowed to return to driving, were extensively evaluated by a physiatrist, psychologist, occupational therapist, and driver training specialist. After they completed a driver training program, the patients were divided into three groups based on their driving program success and follow-ups. Significant differences in the psychological test results were found between Group I (those who drove without any difficulty) and Groups II and III (those who drove limited distance or who failed driver training). Results suggest that patients with significant cognitive and perceptual problems who take training and limit their driving can be safe drivers when they return to driving.

Accidents, Traffic↗
PubMed1991

Seasonal movement and spatial distribution of the sheep ked (Diptera: Hippoboscidae) on Wyoming lambs.

When populations of adult sheep ked, Melophagus ovinus (L.), infesting unshorn lambs were monitored at the University of Wyoming Paradise Farm during 1986, we determined the body regions on which keds would be found at various times of the year and their seasonal population trends for optimal sampling. Results suggested that ked populations were consistently greater on the ribs than on any other area of the lamb. No significant differences were detected for ked populations between sides of a lamb. Distinct and similar ked population trends over time occurred only in the rib, thigh, shoulder, hind leg, belly, and hind flank areas of the lambs, suggesting that a significant seasonal migration did not occur. Analyses for seasonal population fluctuations indicated that ked populations increased in the winter and spring, decreased in summer and then increased again in the fall. Thus, sampling for keds in the rib area at shearing, which begins in March in Wyoming and runs through mid-April, would be an opportune time to detect keds. At other times of the year, the rib area should be inspected for presence of sheep ked.

Animals↗
PubMed1991

Distribution of sandflies (Diptera: Psychodidae) in three vegetation habitats in the Marigat area, Baringo District, Kenya.

A total of 4,467 phlebotomine sandflies representing nine species and two genera were collected using polythene material coated with castor oil in three vegetation types in Marigat area from February to May 1986. Sandfly relative abundance was greatest in the closed-canopy forest (61% of total catch), followed by the open-canopy woodland (38%) and the thicket (1%). Nine species of sandflies were collected in both the closed-canopy forest and the open-canopy woodland. The thicket yielded only four species. The sandfly population in the vegetation was composed of Sergentomyia bedfordi (61%), S. antennatus (31%), S. ingrami (3%), S. schwetzi (2%), and S. africanus (1%). Plebotomus species rarely occurred in the study area. In the closed-canopy forest and the open-canopy woodland, female S. bedfordi were most abundant during the dry season, while males predominated during the wet period. Inversely, more male S. antennatus were collected during the dry season, while females predominated in the open-canopy woodland during the wet season. In the closed-canopy forest, male S. antennatus outnumbered the females during both dry and wet seasons. Both S. antennatus and S. bedfordi increased in abundance during the dry season.

Animals↗
PubMed1991

Relationship of maternal serum ferritin with foetal serum ferritin, birth weight and gestation.

Haemoglobin and ferritin estimations employing the micro-ELISA technique were done in 308 random selected mothers in labour and their newborns. The values of haemoglobin and serum ferritin as well as birth weight and gestation of babies born to iron depleted, and mildly and moderately anaemic mothers were no different from those of newborns of non-anaemic women. However, the values of serum ferritin per se in all these newborns were much lower than what are generally reported from the western countries. Babies born to severely anaemic women, on the other hand, showed elevated levels of haemoglobin and serum ferritin, and lower birth weights and gestation. Thus, mild to moderate iron deficiency in the mother does contribute to lower iron reserves in the foetus, if not frank iron depletion, and severe iron deficiency anaemia to lower birth weight and gestation.

Anemia, Hypochromic↗
PubMed1991

Role of a large plasmid of Salmonella typhi encoding multiple drug resistance.

Twenty isolates of Salmonella typhi from cases of typhoid during the 1989-1990 epidemic in Calcutta were examined. Most isolates (84% of all isolates in the epidemic) were resistant to chloramphenicol, ampicillin, tetracycline and streptomycin but were sensitive to nalidixic acid and ciprofloxacin. Plasmids of 120 kb and 14 kb were identified amongst the multi-drug resistant isolates of S. typhi. However, there was no plasmid in the antibiotic-sensitive isolates. The 120-kb plasmid was transferable and transconjugants were resistant to chloramphenicol, ampicillin, tetracycline and streptomycin. Restriction endonuclease analysis patterns after EcoRI digestion of the 120-kb antibiotic-resistance plasmids from the S. typhi isolates and transconjugants were similar.

Chloramphenicol Resistance↗
PubMed1991

Inhibition of mouse skin protein kinase C by benzoyl peroxide.

Benzoyl peroxide (BP), used widely in dermatologic therapy and by the food industry, is considered a tumor promoter in chemically induced skin. Tumor promoters of both the phorbol and non-phorbol type interact with protein kinase C (PKC). This enzyme, therefore, is regarded as the intracellular receptor for a number of tumor promoters. BP bears some structural resemblance to diacylglycerol (DAG) and thus may exert its action through the PKC system. Based on these observations, we have investigated the effect of BP on PKC from mouse skin. Our data show that unlike phorbol esters, which stimulate PKC (in vivo and in vitro), BP inhibits PKC. Concentration-dependent inhibition by BP is observed when PKC is stimulated by phorbol esters, diacylglycerol, phosphatidyl serine (PS), or a combination of the latter two. BP also inhibits PKC stimulated by (-) Indolactam V, a nonphorbol compound resembling the teleocidins. 3H-phorbol ester binding experiments reveal that inhibition by BP may be due to its interference with the phorbol ester binding site and consequently diacylglycerol binding. The binding data and the inability of BP to inhibit either cyclic AMP-dependent protein kinase I or II imply that BP interacts with PKC, and not with the histone substrate. Results presented here clearly indicate that unlike phorbol and certain non-phorbol type of tumor promoters BP does not stimulate PKC in vitro.

Animals↗
PubMed1991

Japanese encephalitis virus latency in peripheral blood lymphocytes and recurrence of infection in children.

In a study group of 40 children who had been admitted to hospital with acute encephalitis, the disease was due to infection with Japanese encephalitis virus (JEV). Three children developed recurrence of disease 8-9 months later. No virus had been isolated from these three patients during the acute stage of their illness, but virus was recovered from all during the recurrence phase by co-cultivation of their peripheral blood mononuclear cells in primary mouse embryo fibroblast cultures. Virus was also recovered by co-cultivation of peripheral blood mononuclear cells collected 8 months after their acute disease from three out of eight randomly selected asymptomatic children within the study group but not from similar cultures set up from JEV-seronegative children used as controls. Virus was also isolated by co-cultivation of T lymphocytes of asymptomatic children as detected by indirect immunofluorescence or by inoculation in mice.

Cells, Cultured↗