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S Rawat

Publications and source records attributed to S Rawat.

At least 19 recordsLinked to original sources
PubMed2006

A new in-vitro agglutination technique for potency estimation of antisnake venom serum (ASVS).

Traditionally the potency of ASVS is assayed quantitatively by in-vivo neutralization test for lethality in mice. A sensitive and simple in-vitro agglutination assay for the quantitative determination of Antisnake Venom Serum (ASVS) potency is reported. The method is rapid, cheap, simple, economical and above all does not require the use of experimental animals for potency assay of in process, unpurified and purified sera batches. Among in-vitro procedures, agglutination assay was favored in comparison to flocculation as the later was found to give variable results and also time consuming (high Kf value). Before application, the method was standardized and validated for choice and concentration of particulate material (latex vs. bentonite), temperature and optimum antiserum concentration. It is well known fact that venoms lose toxicity on dilution however this study demonstrated that the bentonite adsorbed venoms of the entire four snake species viz., Cobra, Krait, Russell's viper and Echis are stable even up to 30 days of storage. Among five lots each of unpurified serum, unprocessed plasma and purified sera tested, the results were found comparable with universally accepted in-vivo biological assay. The coefficient of correlation was found to be near 1.0 within 95% fiducial limits of acceptance and also significantly less variation was observed in the mean potency values and standard deviations. For all results p value was observed to be <0.01. Results indicate that in-vitro agglutination assay is suitable and can be used for potency estimation of in process as well as unpurified and purified ASVS batches.

Adsorption↗
PubMed2005

Evaluation of the polymerase chain reaction analysis for diagnosis of falciparum malaria in Delhi, India.

Plasmodium falciparum infections are frequently fatal if untreated and hence need to be diagnosed and treated early. Malaria diagnosis, with conventional Giemsa staining as a gold standard, has had several limitations. New rapid and accurate methods are needed for diagnosis. In this study, polymerase chain reaction (PCR) analysis specific for diagnosis of P. falciparum was evaluated. For the study, blood samples were collected from 310 patients suspected of having malaria. PCR analysis for P. falciparum from venous blood and at the same time Giemsa staining of thick and thin blood smears was done. A total of 160 (51.6 %) samples were positive for malarial parasite of which 63 (39.4 %) were positive for P. falciparum by Giemsa staining while 61 (38.1 %) were positive for P. falciparum by PCR analysis. Giemsa staining was time consuming, laborious and may give poor results in cases with low parasitaemia. The PCR analysis for P. falciparum was able to detect 3 cases of low parasitaemia missed initially on Giemsa staining, was 96.8 % sensitive, 100% specific but was very costly, needed a lot of practice and standardization and was time consuming. PCR analysis can be used to supplement the conventional Giemsa staining for reliable diagnosis of falciparum malaria especially in cases with low parasitaemia.

Animals↗
PubMed2003

Rofecoxib-beta-cyclodextrin inclusion complex for solubility enhancement.

Complex formation of rofecoxib and beta-cyclodextrin in aqueous solution and in solid state and the possibility of improving the solubility and dissolution rate of rofecoxib via complexation with cyclodextrin were investigated. Phase solubility studies indicated the formation of an 1:1 complex in solution and the value of apparent stability constant was 769 M(-1). Solid inclusion complexes of rofecoxib and cyclodextrin were prepared by the kneading method in different molar ratios. Differential scanning calorimetry studies indicated the formation of solid inclusion complexes of rofecoxib and cyclodextrin at different molar ratios and the solid complexes exhibited a higher rate of dissolution than the physical mixture and the pure drug.

Algorithms↗
PubMed2003

Evaluation of the direct acridine orange staining method and Q.B.C. test for diagnosis of malaria in Delhi, India.

Conventional Giemsa stained peripheral blood smear examination for demonstration of malarial parasites remains the gold standard for diagnosis of malaria in developing endemic countries. However this technique is time consuming, requires training and may give poor results in cases with low parasitaemia. To overcome these problems and improve diagnostic accuracy two newer tests have been studied and compared with standard Giemsa staining. These are the wet mount fluorescence microscopy of Acridine Orange stained thin blood films (A.O.) and the Quantitative Buffy Coat technique (Q.B.C) for diagnosis of malaria. A.O. staining was found to be 97.5% sensitive and 100% specific for detection of all stages and species of malarial parasite. The Q.B.C assay was found to be 100% sensitive and 97.5% specific for diagnosis of malaria. A.O. staining was very fast and the species identification was easy once the staining was optimised. The Q.B.C. test required considerable amount of practice, costly equipment, however it was fast and in our study was found to be highly sensitive.

Acridine Orange↗
PubMed2001

Clinico-myocological profile of tinea capitis in North India and response to griseofulvin.

There is a paucity of literature on tinea capitis from North India. The response to griseofulvin has not been studied as well. We studied 153 consecutive patients of tinea capitis for clinical patterns, causative dermatophytic species, clinico-etiological correlation, and response to griseofulvin. Culture and sensitivity were done on all patients. All patients were treated with griseofulvin for 6-8 weeks; non-responders were further treated with fluconazole. Ninety percent of the patients were less than 15 years of age, 75% belonged to poor socioeconomic groups and 19% had a family history of tinea capitis. The seborrheic variant was the commonest clinical pattern seen in 47.8% of patients, followed by grey patch, black dot, kerion, and alopecia-areata-like tinea capitis in 35.9%, 8.5%, 6.5% and 1.3% of patients, respectively. Only 66% of patients had a positive culture. T. violaceum was the commonest dermatophytic species isolated in 38% patients. M. audouinii, T. schoenleinii, T. tonsurans, M. gypseum, T. verrucosum and T. mentagrophytes were isolated in 34%, 10%, 9%, 3%, 3% and 3% of patients, respectively. Of the isolates 94% were susceptible to griseofulvin, and 100% were susceptible to fluconazole. By using griseofulvin for 6-8 weeks 97.4% of the patients were cured; nonresponders required therapy with fluconazole for cure. To conclude, tinea capitis is still a disease of younger people of poor socioeconomic status. T. violaceum and M. audouinii are the most common responsible dermatophytes. The response to griseofulvin was excellent, and it should be used as a first line therapy.

Adolescent↗
PubMed2000

The primary structure of the acidic lectin from winged bean (Psophocarpus tetragonolobus): insights in carbohydrate recognition, adenine binding and quaternary association.

The amino acid sequence of the winged bean acidic lectin (WBA II) was determined by chemical means and by recombinant techniques. From the N- and C-terminal sequence, obtained chemically, primers were designed for PCR amplification of the genomic DNA. The PCR product was cloned and sequenced to get the complete primary structure of WBA II. Peptide fragments for sequencing were also obtained by tryptic cleavages of the native lectin. The WBA II sequence showed a high degree of homology with that of WBA I and Erythrina corallodendron lectin (ECorL), especially in the regions involved in subunit association, where there is a very high conservation of residues. This perhaps implies the importance of this particular region in subunit interactions in this lectin. In addition, many of the residues, involved in carbohydrate binding in legume lectins, appear to be conserved in WBA II. The distinct differences in anomeric specificity observed amongst WBA I, WBA II, ECorL and peanut agglutinin (PNA) may be explained by subtle differences in sequence/structure of their D-loops. WBA II binds adenine quite strongly; a putative adenine binding sequence has been identified.

Adenine↗
PubMed1996

Clinical profile and risk factors for oral candidosis in sick newborns.

OBJECTIVES: To provide the clinical profile and assess the significance of various risk factors contributing to the occurrence of oral candidosis in newborns. DESIGN: Case-control study. SETTING: Neonatal Intensive Care Unit (NICU). SUBJECTS: Twenty newborns with oral candidosis and an equal number of age and weight matched controls. INTERVENTIONS: All cases of oral candidosis were treated with local application of 1% Clotrimazole. RESULTS: Oral candidosis was documented in 3.2% (20/650) cases in the NICU. Acute pseudomembranous candidosis was the most common presentation. The mean age of onset was 10.5 days. Candida albicans was isolated in 50% cases in addition to C. tropicalis, C. paratropicalis, C. krusei, C. glabrata and C. parapsilosis. On univariate analysis, male sex, birth asphyxia and prolonged antibiotic therapy had a significant correlation with occurence of oral candidosis in neonates. Out of these, birth asphyxia was the only factor significantly associated with oral candidosis (OR 8.09, 95% CI 1.34-48.8, p = 0.0226) on multivariate analysis. CONCLUSIONS: C. albicans was the predominant isolate in this series of oral candidosis. Clinical manifestations were evident in the second week of life and birth asphyxia was the most important associated perinatal event.

Antifungal Agents↗
PubMed1994

A new antivenom to treat eastern coral snake (Micrurus fulvius fulvius) envenoming.

An Fab based ovine antivenom has been prepared and compared both in vitro and in vivo with two commercial preparations. The product was found to be at least four times more effective on a weight basis. The increased potency, combined with the low incidence of side-effects associated with ovine Fab, should result in a safer, more effective antivenom.

Animals↗
PubMed1994

A comparison of ovine and equine antivenoms.

Commercial antivenoms produced in horses were compared with monospecific antivenoms raised in sheep against Crotalus durissus terrificus, Crotalus atrox, Crotalus adamanteus, Micrurus fulvius fulvius, Naja naja, Naja kaouthia, Echis ocellatus, Vipera lebetina deserti, Vipera berus berus and Vipera ammodytes ammodytes venom. Antibodies raised by immunizing sheep with C. d. terrificus venom were more effective than their equine counterparts in preventing lethal toxicity in mice (ED50), in inhibiting the venom's pharmacological effects (haemolysis, platelet aggregation and coagulation), and in neutralizing phospholipase A2 activity. Comparison of one ovine and three equine F(ab)2 products raised against V. a. ammodytes venom showed that all were at least 95% pure; that all protected mice; and that all contained antibody populations directed against most components of V. a. ammodytes and V. b. berus venoms. The ovine antivenoms generally contained a higher concentration of specific antibodies than the equine products. Finally, the ovine antivenoms raised against E. ocellatus, V. lebetina deserti, V. b. berus, M. f. fulvius and N. naja venoms provided better in vivo protection to mice than the equine antivenoms, but the equine antivenoms to N. kaouthia and C. atrox were more protective than the ovine product.

Animals↗
PubMed1991

Neutralization of kinin-releasing enzymes of crotalid venoms by monospecific and polyspecific antivenoms.

The amounts of kinin-releasing enzymes in the venoms of Crotalus atrox, Crotalus adamanteus, Crotalus scutulatus scutulatus and Agkistrodon piscivorus piscivorus were measured by determining the amounts of kinin released from a sheep kininogen substrate by means of a specific radioimmunoassay. Four monospecific and two commercial polyspecific antivenom IgG samples were tested for their ability to reduce the kinin-releasing activities of the four crotalid venoms measured in vitro. All of the antivenom IgG samples were able to neutralize venom kininogenase activity to varying extents. On of the commercial polyspecific antivenoms was of equal or higher potency than the corresponding monospecific antivenoms for three of the venoms tested, indicating a high degree of cross-neutralization. F(ab')2 and especially Fab fragments of that polyspecific antivenom IgG were also effective in reducing the kinin-releasing activities of the four crotalid venoms.

Animals↗
PubMed1991

In vitro effect of Phyllanthus amarus on hepatitis B virus.

To evaluate the effects of P. amarus on hepatitis B virus (HBV) antigens and HBV-DNA, initial ethanolic extract and subsequent fractions of the plants were prepared. The whole plant material was dried, powdered and extracted with alcohol and subsequently fractionated in hexane, chloroform, butanol and finally in water. All the material were tested for in vitro effects on HBsAg, HBeAg and HBV-DNA in serum samples positive for HBV antigens followed by the screening of respective antigens by Elisa. HBV-DNA was determined by molecular hybridization. The extracts were effective against HBV antigens, the butanol extract being the most potent. Further chromatographic fractions showed an enhanced activity. The active fractions inhibited the interaction between HBsAg/HBeAg and their corresponding antibodies suggesting anti-HBs, anti-HBe-like activity and also an effect on HBV-DNA.

DNA, Viral↗
PubMed1990

In vitro studies on the effect of certain natural products against hepatitis B virus.

Picroliv (active principle from Picrorrhiza kurroa), its major components picroside I, catalpol, kutkoside I, kutkoside, andrographolide (active constituent of Andrographis paniculata), silymarin and Phyllanthus niruri extract were tested for the presence of anti hepatitis B virus surface antigen (anti HBs) like activity. HBsAg positive serum samples obtained from hepatitis B virus (HBV) associated acute and chronic liver diseases and healthy HBsAg carriers were used to evaluate the anti-HBs like activity of compounds/extract. The latter were mixed with serum samples and incubated at 37 degrees C overnight followed by HBsAg screening in the Elisa system. A promising anti-HBsAg like activity was noted in picroliv (and its major components) catalpol, P. niruri which differed from the classical viral neutralization. Picroliv also inhibited purified HBV antigens (HBsAg and HBsAg) prepared from healthy HBsAg carriers. The in vitro testing system appears to be a suitable model to identify an agent active against HBV, prior to undertaking detailed studies.

Adult↗
PubMed1988

Anterior temporal electrodes in complex partial seizures.

Anterior temporal (AT) and sphenoidal (SP) electrodes as well as standard 10-20 electrodes were used to evaluate patients with recent onset complex partial seizures. A total of 58 epileptiform foci were found in 80 patients. AT electrodes significantly improved detection of foci in comparison with 10-20 electrodes. SP electrodes resulted in a small, non-significant increase in detection in comparison to AT electrodes. AT electrodes may be substituted for basal electrodes for the purpose of diagnosis in the majority of patients with recent onset complex partial seizures.

Electrodes↗
PubMed1988

Immunopathological study of spleen during Japanese encephalitis virus infection in mice.

Following intraperitoneal inoculation, Japanese encephalitis virus replicated in peritoneal macrophages, appeared on day 3 in the splenic macrophages of the perifollicular region and later in cells of the periarteriolar lymphoid sheath (PALS) as shown by indirect immunofluorescence. Productive JEV infection was observed both in macrophages and T-cells. Morphological study of spleen during JEV infection revealed proliferative changes, with increased number of macrophages from day 3 p.i. in the perifollicular region followed by accumulation of polymorphonuclear leucocytes which reached a maximum on day 9 p.i. The T dependent areas were considerably enlarged by day 9 and gradually reduced in size by week 3. At later periods germinal centres appeared in the T independent area and were prominent by day 15. The cells containing virus antigen disappeared with the appearance of germinal centres, thus indicating the role of the latter also in virus clearance.

Animals↗