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Biomedical subjects

N Singh

Publications and source records attributed to N Singh.

At least 505 records · Page 28Linked to original sources
PubMed1990

Effect of tumour promoters on poly ADP-ribosylation in human epidermoid carcinoma HeP2 cells.

The present work was undertaken with the basic objective to compare the effect of related tumour promoters phorbol-12-myristate-13-acetate (PMA), benzoyl peroxide (BP) and mezerein (M) on poly ADP-ribosylation in HeP2 cells. PMA, BP and mezerein showed an increase in the enzyme activity to the extent of 66, 89 and 35% respectively. This was accompanied by a drop in NAD levels of 22% with PMA, 24% with BP and 49% with mezerein, PMA-treated cells showed a decrease in the enzyme activity of 42% with superoxide dismutase (SOD) and catalase (CAT), 18% with butylated hydroxy toluene (BHT), 52% with indomethacin and 32% with 3-aminobenzamine (3AB). However, for BP the inhibition was 16% with CAT, 41% with SOD, 18% with BHT, 34% with 3AB and there was no inhibition with indomethacin. The involvement of active oxygen species was supported by a 2.5-fold increase in superoxide anion levels with PMA and BP and no change with mezerein. There was a twofold and a 2.5-fold increase in Ca2+ influx after PMA and BP treatment respectively. It is concluded that PMA and BP mediate their effect on poly ADP-ribosylation through active oxygen species which in turn stimulates the influx of Ca2+ into cells and this may play an important role in signal transduction.

Benzoyl Peroxide↗
PubMed1990

Ultrasonographic localization for renal biopsy.

One hundred and fifty consecutive percutaneous renal biopsies were performed using ultrasonography to localise the site and depth of the lower pole of the left kidney. Renal tissue was obtained in 95% of cases and an accurate histopathological diagnosis was reached in 89% of patients. Gross haematuria following the procedure occurred in 6%, but was usually transient. No other complications were encountered. Ultrasonographic marking of the biopsy site and depth is a quick, simple, accurate and safe method of localizing the kidney for the purpose of a biopsy.

Biopsy↗
PubMed1990

Anti-stress activity in a muramyl-dipeptide.

N-Acetylmuramyl-L-alanyl-D-isoglutamine and some of its derivatives have been examined for anti-stress activity. Amongst these, N-palmitoylmuramyl-L-alanyl-D-isoglutamine is shown to considerably enhance the capacity of animals to endure various types of stress. This indicates that besides acting as immunomodulators and sleep regulators, muramyl dipeptides may also act as anti-stress agents.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1990

Response of Plasmodium falciparum to chloroquine in a tribal area of Madhya Pradesh.

In vivo tests for chloroquine sensitivity of P. falciparum malaria parasites were carried out on a sample of 130 patients (mean age, 21 years) from two PHCs during October-November 1988. During this period 20 cases (5.2%) were found positive for all seven days suggesting the presence of RII/RIII chloroquine resistance. All the resistant cases were treated with metakelfin successfully without any recrudescence.

Adolescent↗
PubMed1990

Synthesis and regulation of lipoprotein lipase in the hippocampus.

Lipoprotein lipase (LPL) expression was determined in adult rat hippocampus and compared to enzyme expression in other brain regions. Hippocampus LPL mRNA levels were at least 2.5-fold higher than those detected in the cerebral cortex, cerebellum, and remaining brain regions. Enzyme mass and activity levels in the hippocampus were also increased to a similar degree. De novo synthesis of LPL in the hippocampus was confirmed by [35S]methionine-labeling of the tissue and identification of a 57 kDa protein obtained by immunoprecipitation. Addition of an excess amount of bovine LPL completely prevented the immunoprecipitation of this protein. The effect of nutritional modulations on brain LPL activity was determined after a 12-h fast. While no significant changes were observed in other regions of the brain, hippocampus LPL activity in fasted rats increased by 60% compared to the fed control group. Simultaneously, fasting reduced adipose LPL activity by 60%. Intraperitoneal injection of ACTH over a 5-day period had no effect on hippocampus LPL activity, while adipose LPL levels increased 2.3-fold and heart LPL levels decreased 1.4-fold. We conclude that LPL is synthesized, active and regulated in a tissue-specific manner in the adult rat hippocampus.

Adipose Tissue↗
PubMed1989

Contamination of an endoscope due to Trichosporon beigelli.

Trichosporon beigelli was isolated from the gastric aspirates of ten patients who had undergone endoscopy. Suspecting fungal contamination of the endoscopic equipment, samples from the biopsy channel, the water bottle, aspiration catheter and the tip of the endoscope were examined. Only the sample from the biopsy channel showed fungal elements on direct examination and grew Trichosporon beigelli. The original source for the fungus was an immunocompromised patient who had undergone endoscopy earlier. This episode occurred despite adherence to apparently adequate disinfection procedures for endoscopes. Because of the risk of cross-infection, especially in immunocompromised patients, it is imperative to take special steps to prevent fungal contamination of endoscopes.

Cross Infection↗
PubMed1989

Cell Walls of Tobacco Cells and Changes in Composition Associated with Reduced Growth upon Adaptation to Water and Saline Stress.

The relative mass of the cell walls of tobacco (Nicotiana tabacum L.) cells adapted to grow in medium containing 30% polyethylene glycol 8000 or 428 millimolar NaCl was reduced to about 50% of that of the walls of unadapted cells. Cellulose synthesis was inhibited substantially in adapted cells. The proportions of total pectin in walls of unadapted and adapted cells were about the same, but substantial amount of uronic acid-rich material from walls of cells adapted to either NaCl or polyethylene glycol was more easily extracted with cold sodium ethylenediamine tetraacetic acid solutions (NM Iraki et al. [1989] Plant Physiol. 91: 39-47). We examined the linkage composition of the pectic and hemicellulosic polysaccharides to ascertain chemical factors that may explain this difference in physical behavior. Adaptation to stress resulted in the formation of a loosely bound shell of polygalacturonic acid and rhamnogalacturonan. Pectins extracted from walls of adapted cells by either cold sodium ethylenediamine tetraacetic acid or hot ammonium oxalate were particularly enriched in rhamnose. Compared to pectins of unadapted cells, rhamnosyl units of the rhamnogalacturonans of adapted cells were more highly substituted with polymers containing arabinose and galactose, but the side groups were of greatly reduced molecular size. Possible functional roles of these modifications in cell wall metabolism related to adaptation to osmotic stress are discussed.

Journal Article↗
PubMed1989

Bio-environmental control of malaria in a tribal area of Mandla district, Madhya Pradesh, India.

Bizadandi block of District Mandla was selected for demonstration of bio-environmental control of malaria. The project presently covers 80 experimental villages and 12 control villages. In this area, because of indifferent surveillance and spraying in the past (from 1978-86) the API was reported low and the parasite reservoir in the community had built up over the years. At the outset of the study the malaria prevalence was high with preponderance of P. falciparum. Densities of A. culicifacies were very high and A. fluviatilis was also present. P. falciparum predominated in both experimental and control area during 1988 than in 1987. Annual blood examination rate (ABER) was 73.6 and 57.5 and annual parasite incidence (API) was 114.7 and 228.0 in experimental and control villages in 1987, while in 1988, ABER and API was 63 and 73 and 112 and 316 in experimental and control, respectively. There was constant stabilization of Pf in neighbouring blocks in 1988 while in experimental areas Pf percentage has come down appreciably during March to June. It is very alarming to note that the parasite reservoir in control villages was sufficient to maintain active transmission even when antimalarial activities are at a peak. The application of residual insecticides like DDT and HCH has no tangible impact on the reduction in vector densities and the transmission of malaria. Even if a replacement insecticide like malathion is used it may produce very limited impact on vector densities in such forested zones. Thus, there is an urgent need to intensify integrated malaria control operations in the area on long term basis.

Animals↗
PubMed1989

Mosquito breeding in rice fields and its role in malaria transmission in Mandla district, M.P.

A study of the breeding of mosquitoes in the rice field agro-ecosystem was carried out in Mandla district during 1987 and 1988. Results revealed that mosquito breeding commences in July and ends in October. Mosquito breeding in rice fields is inversely proportional to the distance from village. A. culicifacies breeds in rice fields up to a plant height of 20 cm and then gradually declines and becomes scarce, and is taken over by A. theobaldi and A. splendidus. A. fluviatilis breeds in irrigation channels almost throughout the rice growing season. There were a large number of other mosquito breeding sites which increased enormously with the onset of rains. The precise role of rice fields in maintaining high malaria transmission could not be established but the rice field agro-ecosystem contributed significant vector populations.

Adult↗
PubMed1989

Carboxyhaemoglobin and serum cholesterol levels in smokers.

Carboxyhaemoglobin (COHb) and serum cholesterol levels were studied in twenty five chronic smokers, smoking different quantities of cigarettes, biris and "hooka" for more than ten years and compared with equal number of age and sex matched non-smoker controls. COHb levels were found to be significantly higher (P less than 0.001) in chronic smokers as compared to non-smokers while no significant difference (P greater than 0.1) was found in serum cholesterol levels between the two groups. Cigarette smokers had a higher COHb level as compared to biris smokers (P less than 0.001).

Adult↗
PubMed1989

Drug resistant P. falciparum in Madras (Tamil Nadu) and district Jabalpur (Madhya Pradesh).

WHO micro in vitro tests for chloroquine resistance in P. falciparum were carried out during November, 1987 in Madras city, Tamil Nadu and in Kundam PHC of Jabalpur district, Madhya Pradesh. Out of 6 samples tested from Madras city, 5 showed resistance to chloroquine. Likewise, out of 14 samples tested in Jabalpur, 12 (85.7%) showed resistance to chloroquine. All the 20 samples showed normal susceptibility to mefloquine.

Adolescent↗
PubMed1989

A focus of high degree chloroquine resistant P. falciparum in Mandla district (M.P.).

A study on the bioenvironmental control of malaria was launched in Bizadandi block (Mandla district, M.P.) in May 1986. Besides intervention, using environmental management methods and larvivorous fishes, weekly surveillance and chloroquine administration at 25 mg/kg body weight was practiced. Studies during 1987 revealed that a large number of P. falciparum cases did not respond to the standard anti-malarial treatment. Therefore, systematic 28 day in vivo studies were taken up on the follow-up of P. falciparum cases after administration of 3 day course of 25 mg/kg body weight as per the WHO procedure. Results revealed a high proportion of drug resistant cases belonging to RI (237), RII and RIII (182) category. In vivo studies on the sensitivity to metakelfin showed that some cases were resistant to this drug. There is an urgent need to eradicate this focus before it starts spreading to other areas.

Adolescent↗