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Biomedical subjects

R C Sharma

Publications and source records attributed to R C Sharma.

At least 109 records · Page 6Linked to original sources
PubMed1992

Sensitivity of mosquito-pathogenic bacterial strains to various antibodies.

Four strains of Bacillus sphaericus, 1593, 2362, 9001 and 9002, B. thuringiensis H-14 and B. thuringiensis neoleonensis were tested for sensitivity against 18 antibiotics. The results revealed that all the four strains of B. sphaericus are resistant to colistin, nalidixic acid, polymyxin B and streptomycin. However, B. thuringiensis H-14 was resistant to 9 antibiotics, viz. ampicillin, cephalexin, carbenicillin, co-trimoxazole, colistin, cloxacillin, penicillin, nitrofurantoin and polymyxin B whereas B. thuringiensis neoleonensis was found to be resistant to 8 antibiotics. These results may help in isolation of potential and resistant mosquito pathogenic bacteria.

Animals↗
PubMed1992

Gujarat model of health management information system with reference to malaria.

The Gujarat model of health management and information system has been developed with the objective of reducing the work load of health workers at all levels pertaining to record keeping and report preparation for enhancing the quality of health services, as well as for better implementation and timely monitoring of health programmes. Pro formas currently in use under various health programmes have been reorganized and updated. For monitoring malaria, the total number of registers has been reduced from seven to one, reporting forms from 23 to six and the number of columns in reporting forms from 493 to 59. The model is expected to save the working time of laboratory technicians (15%) and multi-purpose health supervisors (5%) at PHC level and of all workers (100%) engaged in report preparation at district, state and national levels. The data generated by using this model are expected to be of high quality and accuracy and should lead to more rational planning.

Humans↗
PubMed1992

Microscopic diagnosis of malaria in Kheda district of Gujarat.

A study conducted in 1990 revealed that 2% (range 0.6-4.8) of negative blood smears were mislabelled as positive, and 6.7% of positive blood smears were mislabelled as negative. A result of such mislabelling would be inadequate treatment of a large number of patients. Hence the need to look into the training aspect and system of supervision of laboratory technicians. The present system of cross-checking of blood smears at different levels also needs to be reviewed. A study which could address itself to these needs is indicated.

Adult↗
PubMed1991

A phenotype conferring selective resistance to lipophilic antifolates in Chinese hamster ovary cells.

Trimetrexate, a lipid-soluble analogue of methotrexate, appears to enter mammalian cells by passive diffusion, thus circumventing the methotrexate transport system which is frequently a subject for alterations leading to methotrexate resistance. Using a single-step selection protocol with trimetrexate, we have isolated 45 clonal variants and found the majority of them to be selectively resistant to lipophilic antifolates while retaining their sensitivity to methotrexate and drugs involved in multidrug resistance. The majority of spontaneously induced trimetrexate-resistant clones showed a change in neither the mRNA levels of dihydrofolate reductase (24 of 30) and P-glycoprotein (26 of 30) nor their gene copy numbers, whereas a small fraction of clones (4 of 30) showed multidrug resistance gene amplification and P-glycoprotein mRNA overexpression. gamma-Irradiation prior to selection markedly enhanced the frequency of trimetrexate resistance (100-fold after 1000 rads). None of the gamma-ray-induced trimetrexate-resistant clones (0 of 15) had evidence of dihydrofolate reductase and multidrug resistance gene amplification and/or overexpression. Flow cytometry data on trimetrexate-resistant clones showed no defect in the transport of trimetrexate. Verapamil, a modulator of the multidrug resistance phenotype, had no cytotoxic effect on parental and trimetrexate-resistant clones. However, when present with trimetrexate, verapamil (0.3-0.6 microM) reversed the lipophilic antifolate-resistant phenotype in clones that had invariant levels of P-glycoprotein and dihydrofolate reductase. This selective resistance to lipid-soluble antifolates was initially unstable but became stable after continued drug-selective growth. Two-dimensional gel electrophoresis showed some differences in protein(s) that may potentially be associated with this phenotype of selective resistance to lipophilic antifolates. We conclude that a gamma-radiation-enhanceable, verapamil-reversible, stable phenotype of selective resistance to lipid-soluble antifolates frequently emerges which requires neither the amplification nor the overexpression of dihydrofolate reductase or multidrug resistance genes.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1991

Relationship of arterial wall uptake of radiolabeled liposomes to the presence of monocyte/macrophage cells in the hypertensive and atherosclerotic arterial wall.

In vivo radiolabeled liposome uptake in 5 sham-operated, 7 coarctation-induced hypertensive, and 8 atherosclerotic arterial walls from New Zealand White rabbits was compared to determine the mechanism of arterial wall uptake of liposomes. Uptake between the three groups was significantly different (P less than 0.001) with a 3-fold difference in uptake between the sham-operated and hypertensive groups and the hypertensive and atherosclerotic groups. Liposome uptake was significantly higher in the atherosclerotic group of animals (P less than 0.05). Avidin-biotin immunoperoxidase staining for monocyte/macrophage cells revealed that liposome uptake increased concomitantly with arterial wall monocyte/macrophage cellular invasion and that liposome localization, determined by autoradiography, paralleled the monocyte/macrophage cellular distribution in both hypertensive and atherosclerotic arterial walls. This study provides the first direct evidence that liposomes can escape from the circulation and enter the diseased arterial wall. Furthermore, it suggests that one possible mechanism of arterial wall uptake of liposomes is via the monocyte/macrophage cell which avidly and preferentially engulfs liposomes and then passively carries them into the arterial wall during hypertensive and atherosclerotic lesion development. Liposomes could potentially be used to carry agents into the arterial wall in the study of arterial wall lesion development.

Animals↗
PubMed1991

Antimicrobial and cytotoxic activity of transition metal chelates with some heterocyclic imines.

Cu(II), Ni(II), Co(II), and Zn(II) chelates with two heterocyclic imines derived from 2-furylglyoxal-2(1)-aminothiophenol (FGATP) and 2-thiophenylglyoxal-anthranilicacid (TGAA) were synthesized. Elemental analysis, molar conductance, magnetic measurements and IR and electronic spectral data were explored to elucidate their probable structures. Different crystal field parameters were also calculated to ascertain the geometry of the resulting chelates. All the ligands and their metal chelates were screened, in vitro, for their antimicrobial activity against two bacteria: S. aureus and E. coli and two fungi, viz: A. niger and C. albicans. The in vitro cytotoxic activity of all the compounds was also assessed.

Anti-Bacterial Agents↗
PubMed1991

Biting rhythms of malaria vector Anopheles culicifacies in Kheda district, Gujarat.

All night collections on bovine baits were made in 6 villages of Kheda district, Gujarat. During 70 all night bait collections from January to December 1989, a total of 2290 An. culicifacies were collected. An. culicifacies mostly exhibited bimodal rhythms with a seasonal shift in peak biting activities. During the cold season most biting occurred just after dusk and during the warm season late at night. An. culicifacies was more active during moonless hours and its activity showed no correlation with temperature and humidity during most part of the year.

Animals↗
PubMed1991

Isolation and laboratory evaluation of an indigenous strain of Bacillus sphaericus (9001).

An indigenous strain of Bacillus sphaericus H5a (9001), possessing high insecticidal properties, was isolated from diseased larvae of Culex species. This strain in comparison with the known strains of B. sphaericus, i.e., 1593 and 2362, was found to be promising against the fourth instar larvae of Anopheles culicifacies, An. stephensi, An. subpictus, Aedes aegypti and Culex quinquefasciatus. B. sphaericus 9001 is highly stable and virulent through 25 successive transfers and thus can be effectively used as a biocontrol agent against immature stages of mosquitoes.

Animals↗
PubMed1991

Quantitative structure-activity relationship studies of inhibitors of gastric (H+/K+)-ATPase.

The (H+/K+)-ATPase enzyme inhibitory activity of omeprazole analogues (Figure 1) and 1-aryl-4-methyl-2,3-dihydropyrrolo[3,2-c]quinolines (Figure 2) was found to be significantly correlated with electronic (sigma) or pKa parameter that governs the basicity of the molecules. The former compounds are representative of irreversible blockers, and the latter of reversible blockers. Inclusion of hydrophobic (pi) and/or steric (Es) parameters sometimes led to improvement in the correlations, suggesting that these parameters may play a role in the formation of a cyclic intermediate. The derived significant correlation equations strongly support a mechanism of action, first proposed by Lindberg et al., involving such a cyclic intermediate.

Adenosine Triphosphatases↗
PubMed1991

Seasonal prevalence of anophelines in Kheda district, Gujarat.

Seasonal changes in the population structure of anophelines were studied in Kheda district, Gujarat. Mosquito collections were made from the villages of Nadiad taluka, representing 3 different physiographic zones. Maximum number of anopheline species (13) were recorded from canal irrigated area followed by 11 species from non-canal irrigated and 8 species from riverine areas. Four anophelines namely An. subpictus, An. culicifacies, An. annularis and An. stephensi were predominant. High densities of An. culicifacies and An. subpictus were recorded in March and August. Results of a four year study (1985 to 1988) on the population of anophelines from 3 different physiographic entities showed marked differences in the seasonal abundance of different species.

Animals↗
PubMed1991

A quantitative survey of anophelines in six villages of Kheda District, Gujarat.

Sampling of anophelines from six villages of Kheda district, Gujarat was done using four different methods viz. indoor resting, outdoor resting, bovine bait trap and immature collections. A total of 113,487 specimens representing 17 species were collected. An. subpictus (66.51 per cent) was most abundant species followed by An. culicifacies (14.12 per cent) and An. tessellatus (5.24 per cent). Bovine bait collections were found most productive yielding maximum species and highest number of anophelines per unit of collection efforts. Indoor resting collections yielded poorest diversity and greater number of specimens per unit of collection effort than outdoor resting collections. Maximum diversity was observed in outdoor collections. Most of the species exhibited unimodal prevalence.

Animals↗