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Biomedical subjects

S K Sarkar

Publications and source records attributed to S K Sarkar.

At least 37 records · Page 2Linked to original sources
PubMed1997

The status of ORT (oral rehydration therapy) in Bangladesh: how widely is it used?

During 1980-1990 BRAC, a Bangladeshi non-governmental organization, taught over 12 million mothers how to prepare oral rehydration therapy (ORT) at home with lobon (common salt) and gur (unrefined brown sugar). This was followed by a strong promotion and distribution of prepackaged ORS by various agencies including the government. In 1993 we assessed knowledge of ORT preparation, its local availability and its use for the management of diarrhoea. Over 9000 households in 90 villages were revisited; 306 government outreach health workers, 296 drug sellers, and 237 village doctors were interviewed; 152 government facilities and 495 pharmacies/shops were visited. ORT prepared by mothers in a sub-sample of the households was analyzed for chloride content and interviewers collected information on use of ORT for diarrhoeal episodes occurring in the preceding two weeks. The data quality was assessed through a resurvey of sample respondents within two weeks of the first interview. Over 70% of the mothers could prepare a chemically 'safe and effective' ORS. A significant proportion of these mothers were very young at the time of the mass campaigns using house to house teaching, implying an intergenerational transfer of the knowledge on ORT. ORT was found to be used in 60% of all diarrhoeal episodes, but the rate varied with the type of diarrhoea, being highest for daeria (severe watery diarrhoea) and lowest for amasha (dysentery). Drug sellers and village doctors now recommend ORT much more frequently than before. Members of the medical profession (qualified and unqualified) still lag behind in prescribing the use of ORT. The availability of pre-packaged ORS in rural pharmacies has improved enormously. There is convincing evidence that the widescale promotion in the past of ORS for dehydration in diarrhoea has led to this marked improvement today. Nevertheless the use of rice-based ORS, culturally appropriate messages and the promotion of ORS with food offer opportunities to further improve the utilization of ORT.

Adolescent↗
PubMed1996

Disease-modifying activity of SK&F 106615 in rat adjuvant-induced arthritis. Multiparameter analysis of disease magnetic resonance imaging and bone mineral density measurements.

OBJECTIVE: To evaluate the effect of SK&F 106615 on joint integrity in rats with adjuvant-induced arthritis (AIA). METHODS: AIA was induced in Lewis rats on day 0, and the animals were treated either prophylactically (days 0-16 or days 0-23) or therapeutically (days 10-23) with SK&F 106615. Efficacy was determined by measurements of paw inflammation, bone mineral density (BMD) using dual x-ray absorptiometry, and magnetic resonance imaging (MRI). Joint integrity was also determined histologically, and serum interleukin-6 (IL-6) levels were measured as a marker of the antiinflammatory effects of the compound. RESULTS: Prophylactic treatment (days 0-16) of AIA rats with SK&F 106615 significantly inhibited paw volume at doses of 545 mg/kg/day given orally on 5 days each week. Extensive evaluation of joint integrity in rats treated with SK&F 106615 20 mg/kg/day orally for 23 days showed inhibition of paw volume, normalization of BMD, and significant improvement in disease by MRI and histologic assessment compared with the AIA controls. Elevated levels of serum IL-6 in AIA rats were reduced dramatically by SK&F 106615. Therapeutic treatment (days 10-23) resulted in similar protective effects measured by paw inflammation, BMD, and MRI. In the therapeutic protocol, serum IL-6 appeared to be a more sensitive marker of antiinflammatory activity than paw edema. CONCLUSION: Symptoms of AIA in rats are significantly reduced by prophylactic and therapeutic treatment with SK&F 106615. Of particular note, this compound appears to exert a protective effect on joint integrity and to have disease-modifying properties.

Absorptiometry, Photon↗
PubMed1996

Triterpenoid saponins from Gymnema sylvestre.

Besides six known gymnemic acids, four new tritepenoid saponins, gymnemasins A, B, C and D, isolated from the leaves of Gymnema sylvestre, were identified as 3-O-[beta-D-glucopyranosyl(1-->3)-beta-D-glucuronopyranosyl]-22-O- tigloyl- gymnemanol, 3-O-[beta-D-glucopyranosyl (1-->3)-beta-D-glucuronopyranosyl]-gymnemanol, 3-O-beta-D-glucuronopyranosyl-22-O-tigloyl-gymnemanol and 3-O-beta-D-glucuronopyranosyl-gymnemanol, respectively. The aglycone, gymnemanol, which is a new compound, was characterized as 3 beta, 16 beta, 22 alpha, 23, 28-pentahydroxyolean-12-ene.

Carbohydrate Sequence↗
PubMed1996

A note on assessing the superiority of a combination drug with a specific alternative.

This paper describes a new statistical test for evaluating the efficacy of a combination therapy. This procedure is conservative and makes use of prior information in an attempt to improve power for a specific prespecified alternative. The power of this procedure is substantially greater than that of the min test when the effects of the components are equal or nearly equal and are accurately predicted. This procedure could be of value for evaluating combinations of well-studied drugs.

Data Interpretation, Statistical↗
PubMed1995

Effects of chemically-induced stress on blood viscosity of rabbits.

Disease-induced stress in a living system needs its characterization before quantification. We address this problem by studying the flow behaviour of blood of rabbits. The flow behaviour of rabbit blood, both normal and streptozotocin-induced diabetic was observed by plotting viscosity levels against known shear stress. The curves obtained from normal animals showed a curvilinear relationship between eta and tau, whereas the curves obtained from the blood of the induced diabetic animals showed a 'thixotropic' nature i.e. viscosity varies inversely with shear stress. The results obtained were (a) increased viscosity associated with increasing doses, (b) the lower the shear stress, higher was the viscosity and (c) significant variation of viscosity levels between normal and induced-diabetic rabbits observed by increased stress. The possible interpretation of the results in the light of rheological properties of blood is discussed.

Animals↗
PubMed1994

Humoral immunity response in malignancies with special reference to the effect of radiotherapy.

In view of the variability in the findings recorded by different authors in the level of immunoglobulins in patients suffering from malignancies, a study on 34 cases of six types of malignancies treated with radiotherapy (telecobalt and telecesium) was carried out to record the humoral response and also to compare the response during radiotherapy and after radiotherapy in these cases. Serum of 20 age-matched normal volunteers served as normal control. The study recorded that the pretherapy levels of IgA and IgG were raised in most of the cases; but the IgM was decreased than that of the control level. This is probably due to the fact that the selective clones of cells producing different types of immunoglobulins are responding to the malignancies in different ways. The midtherapy level of all immunoglobulins showed the value lower than the pretherapy level, but recovery was observed in the post-therapy period with all immunoglobulins in all the cases irrespective of the histological types of malignancies. It was also apparent from this study that the post-therapy gain in the level of immunoglobulins over midtherapy level was more pronounced in cases having telecobalt therapy. Assessment of humoral response in 25 patients suffering from squamous cell carcinoma of different grades revealed that the midtherapy fall and subsequent post-therapy gain had no definite correlation with grading.

Adult↗
PubMed1994

Immunofluorescence analysis of immunoglobulin bearing lymphocytes in the Indian fruit bat: Pteropus giganteus.

The immunologic cell types of the Indian fruit bat, P. giganteus, were characterized on the basis of cell surface Ig markers. Rabbit anti-rat IgM and IgG demonstrated IgM or IgG bearing cells in the nylon wool adherent lymphocyte population, thereby suggesting their equivalence to the B cells of recently evolved mammals including man. Relative proportion of these Ig+ surface bearing cells was about one-half of the bone marrow lymphocytes, one-third of mesenteric lymph node lymphocytes, and two-thirds of the splenic and peripheral blood lymphocytes. Considering the early origin of Megachiropters (fruit bats) in mammalian evolution, it is suggested that surface characteristics of typical mammalian lymphocytes like Ig markers as such or as genomic messages existed at the time of evolution of Class Mammalia. The high percentage of surface Ig+ cells in the peripheral circulation of bats suggests a "natural immunodeficiency state", which may be equivalent to immunodeficiency state in humans.

Animals↗
PubMed1993

Magnetic resonance microscopy in rat skeletal research.

Noninvasive evaluation of skeletal tissue, particularly certain sites that tend to be predisposed to disease, is critical in understanding the pathogenesis, progression, and successful treatment of various diseases like osteoporosis, rheumatoid arthritis, and osteoarthritis. Although several noninvasive techniques are currently available to evaluate skeletal tissues, they all have critical limitations. We report here a systematic study to compare the morphological changes (overall profile and tissue architecture) in the proximal tibiae and coccygeal vertebrae of a young growing rat and an older retired female breeder rat using 2- and 3-dimensional MR (magnetic resonance) microscopy and histology. We have obtained MR microimages of intact rat tibiae and vertebrae with resolution upto 24 24 250 microns and have found excellent correlations between MR microscopy results and histological assessment.

Aging↗
PubMed1992

Hepatoprotective activity of Azadirachta indica leaves on paracetamol induced hepatic damage in rats.

Effect of A. indica leaf extract on serum enzyme levels (glutamate oxaloacetate transaminase, glutamate pyruvate transaminase, acid phosphatase and alkaline phosphatase) elevated by paracetamol in rats was studied with a view to observe any possible hepatoprotective effect of this plant. It was interesting to observe that serum enzyme levels were much elevated in paracetamol induced animals than in those receiving a combination of paracetamol and lead extract. It is stipulated that the extract treated group was protected from hepatic cell damage caused by paracetamol induction. The findings were further confirmed by histopathological study of liver.

Acetaminophen↗
PubMed1992

Ontogenetic and comparative analysis of LDH isozymes in the three species of Indian major carp.

Expression patterns of lactate dehydrogenase (LDH) isozyme were investigated in embryonic and post embryonic stages of Labeo rohita, Cirrhinus mrigala and Catla catla using starch gel electrophoresis. Species specific and differential enzyme locus (gene) expression patterns were found in LDH up to 18th hr of study. The isozyme up to 36th hr after fertilization seemed to be completely active and showed electrophoretic patterns very similar to those of the adults. Comparative analysis of the isozyme of the three species permitted species identification even during the embryonic stages when it is impossible to identify on morphological characters only. Also, the genetic studies indicated different taxonomical and evolutionary histories of the species.

Animals↗
PubMed1991

Enzymatic properties of mutant Escherichia coli tryptophan synthase alpha-subunits.

Thirty-nine mutant tryptophan synthase alpha subunits have been purified and analyzed (in the presence of the beta 2-subunit) for their enzymatic (kcat, Km) behavior in the reactions catalyzed by the alpha 2.beta 2 complex, the fully constituted form of this enzyme. The mutant alpha subunits, obtained by in vitro random, saturation mutagenesis of the encoding trpA gene, contain single amino acid substitutions at sites within the first 121 residues of the alpha polypeptide. Four categories of altered residues have been tentatively assigned roles in the catalytic functions of this enzyme: 1) catalytic residues (Glu49 and Asp60); 2) residues involved in substrate binding or orientation (Phe22, Thr63, Gln65, Tyr102, and Leu105); 3) residues involved in alpha.beta subunit interactions (Gly51, Pro53, Asp56, Asp60, Pro62, Ala67, Phe72, Thr77, Pro78, Tyr102, Asn104, Leu105, and Asn108); and 4) residues with no apparent catalytic roles. Catalytic residue alterations result in no detectable activity in the alpha-subunit specific reactions. Substrate binding/orientation roles are detected enzymatically primarily as rate defects; alterations only at Tyr102 result in apparent Km effects. alpha.beta interaction roles are detected as rate defects in all tryptophan synthase reactions plus Km increases for the alpha-subunit substrate, indole-3-glycerol phosphate, only when L-serine is present at the beta 2-subunit active site. A substitution at only one site, Asn104, appears to be unique in its potential effect on intersubunit channeling of indole, the product of the alpha-subunit specific reaction, to the beta 2-subunit active site.

Catalysis↗
PubMed1991

Yb-DTPA, a novel contrast agent in magnetic resonance imaging: application to rat kidney.

We have developed a novel contrast agent, ytterbium-diethylenetriamine pentaacetic acid (Yb-DTPA), for magnetic resonance imaging (MRI) and its mechanism of action is predominantly by the susceptibility mechanism. We have applied this contrast agent for renal MRI studies. We also demonstrate that Yb-DTPA has a renal clearance similar to that of inulin in rats and may therefore be useful for the estimation of glomerular filtration rate.

Animals↗
PubMed1991

Analysis of immunocompetent cells in the bat, Pteropus giganteus: isolation and scanning electron microscopic characterization.

Immunocompetent cells of the Indian fruit bat (P. giganteus) were characterized by differential surface adhesiveness and surface topography. We observed three cell types: (1) plastic adherent with pseudopodia; (2) nylon wool adherent with small microvilli and pits; and (3) a nylon wool nonadherent with comparatively smooth surfaces. These cell types resemble, respectively, macrophages, B cells and T cells of other mammals, including mice and humans. The disposition of microvilli on the B-type cell surface changes significantly after immunization, which suggests modulation of the molecular organization of the cell membrane and its fluidity. The proportions of these three cell types are not much different from those found in mice. Follicular dendritic cells, capable of retaining antigen for long periods in mice, have also been detected in bats. Further characterization of immunocompetent cells wil help in understanding the mechanism of immune responses in bats.

Animals↗
PubMed1991

Quantitative comparison of magnetic resonance imaging (MRI) and histologic analyses of focal ischemic damage in the rat.

Hemispheric swelling and area of infarction, two parameters of cerebral focal ischemic damage, were identified and quantified from T2-weighted magnetic resonance imaging (MRI) two days after occlusion of the middle cerebral artery (MCAO) in spontaneously hypertensive rat (SHR) brains. Results were compared with these measures quantified from 2,3,5-triphenyltetrazolium hydrochloride (TTC)- and hematoxylin and eosin (H&E)-stained histologic sections in the same brains. The degree of hemispheric swelling and infarct size determined by MRI were highly correlated to the measurements as determined in the TTC- and H&E-stained tissues. These results demonstrate that the focal ischemic damaged area and associated tissue swelling identified by MRI is quantitatively similar to, and thus, is representative of actual tissue damage/changes that can be identified by gross or histologic examination.

Animals↗
PubMed1991

Serovars of multi-antibiotic resistant Escherichia coli from the freshwater environs of Calcutta, India.

For a period of one year (March 1987 to February 1988), the incidence of Escherichia coli was determined in water, sediment and plankton collected from two sampling sites in a freshwater lake extensively used by humans and animals. Densities of E. coli associated with plankton was the lowest while sediments, especially at site 2, harbored high densities of the organism. Correlation coefficients revealed that the density of E. coli in water samples was linearly correlated to temperature, pH of water, sediment and humidity. Stepwise multiple regression analysis, however, showed that sediment temperature was the dominant variable which could explain 27% of the observed variation in the numbers of E. coli in the overlying waters (p = less than 0.001). Of the 150 environmental E. coli strains which were characterized, 31 (20.7%) were found to belong to the classic enteropathogenic E. coli (EPEC) serogroups. Seven of the serogroups among the environmental EPEC strains were also encountered from EPEC strains isolated from human cases during a concurrent clinical study. None of the 150 environmental strains were enterotoxigenic or enteroinvasive but 4 strains possessed HEp-2 cell adhesive factor. With the exception of one, all the EPEC strains isolated were multi-drug resistant. From this study, it was evident that the lake is an important source of infection of EPEC and other related diarrheagenic E. coli.

Diarrhea, Infantile↗