Biomedical subjects

A K Tripathi

Publications and source records attributed to A K Tripathi.

At least 19 recordsLinked to original sources

PubMed2006

Adenosine diphosphate ribosylation of dinitrogenase reductase and adenylylation of glutamine synthetase control ammonia excretion in ethylenediamine-resistant mutants of Azospirillum brasilense Sp7.

Azospirillum brasilense is a nitrogen-fixing, root-colonizing bacterium that brings about plant-growth-promoting effects mainly because of its ability to produce phytohormones. Ethylenediamine (EDA)-resistant mutants of A. brasilense were isolated and screened for their higher ability to decrease acetylene and release ammonia in the medium. One of the mutants showed considerably higher levels of acetylene decrease and ammonia excretion. Nitrogenase activity of this mutant was relatively resistant to inhibition by NH(4)Cl. Adenosine triphosphate ribosylation of dinitrogenase reductase in the mutant did not increase even in presence of 10 mM NH(4)Cl. Although the mutant showed decreased glutamine synthetase (GS) activity, neither the levels of GS synthesized by the mutant nor the NH (4) (+) -binding site in the GS differed from those of the parent. The main reason for the release of ammonia by the mutant seems to be the fixation of higher levels of nitrogen than its GS can assimilate, as well as higher levels of adenylylation of GS, which may decrease ammonia assimilation.

Adenosine Diphosphate Ribose↗

PubMed2006

Quantitative determination of reserpine, ajmaline, and ajmalicine in Rauvolfia serpentina by reversed-phase high-performance liquid chromatography.

A sensitive and reproducible reversed-phase high-performance liquid chromatography (HPLC) method using photodiode array detection is established for the simultaneous quantitation of important root alkaloids of Rauvolfia serpentina, namely, reserpine, ajmaline, and ajmalicine. A Chromolith Performance RP-18e column (100 x 4.6-mm i.d.) and a binary gradient mobile phase composed of 0.01 M (pH 3.5) phosphate buffer (NaH(2)PO(4)) containing 0.5% glacial acetic acid and acetonitrile are used. Analysis is run at a flow rate of 1.0 mL/min with the detector operated at a wavelength of 254 nm. The calibration curves are linear over a concentration range of 1-20 microg/mL (r = 1.000) for all the alkaloids. The various other aspects of analysis (i.e., peak purity, similarity, recovery, and repeatability) are also validated. For the three components, the recoveries are found to be 98.27%, 97.03%, and 98.38%, respectively. The limits of detection are 6, 4, and 8 microg/mL for ajmaline, ajmalicine, and reserpine, respectively, and the limits of quantitation are 19, 12, and 23 microg/mL for ajmaline, ajmalicine, and reserpine, respectively. The developed method is simple, reproducible, and easy to operate. It is useful for the evaluation of R. serpentina.

Ajmaline↗

PubMed2006

Effect of placental-extract gel and cream on non-healing wounds.

OBJECTIVE: To compare the effects of topical placental-extract gel and cream in the treatment of chronic non-healing wounds with regard to wound healing and discomfort during dressing change. METHODS: A sample of 120 patients attending the wound clinic at University Hospital, Varanasi, India, with wounds of more than six weeks' duration were enrolled into the study. They were alternately allocated to group A (topical application of placental-extract gel) or group B (placental-extract cream). Wound biopsy was performed, and swab culture and sensitivity were taken. Wound size was measured, and visual analogue scale (VAS) scores for pain and discomfort at dressing change were recorded at weekly follow-up in both groups. Biopsy was repeated after two weeks of treatment and sent for histopathological examination for assessment of angiogenesis in 25 cases from each group. RESULTS: One hundred patients completed the study. More than 50% wound healing was observed after eight weeks in 72% of group A patients and 74% of group B patients (p = 0.75). Microscopic angiogenesis grading system (MAGS) scores were similar in both groups (not statistically significant, p = 0.92). The VAS scores for pain and discomfort were lower in group B (statistically significant, p < 0.02). CONCLUSION: Placental-extract gel and cream are both effective topical agents for chronic non-healing wounds. However, there is less pain and discomfort during dressing change with the placental-extract cream, which we thus recommend for topical application in chronic non-healing wounds.

Administration, Cutaneous↗

PubMed2006

Protective effect of melatonin against propoxur-induced oxidative stress and suppression of humoral immune response in rats.

Effect of melatonin in attenuation of propoxur induced oxidative stress and suppression of humoral immune response was studied in rats. Oral administration of propoxur (10 mg/kg) increased lipid peroxidation in serum after 28 days treatment. Superoxide dismutase, catalase and glutathione were also altered following propoxur exposure. In addition propoxur exposure markedly suppressed humoral immune response as assessed by antibody titre and plaque forming cell assay. Simultaneous treatment with melatonin (5 mg/kg, ip) markedly attenuated the effect of propoxur on (a) lipid peroxidation, (b) oxidative stress parameters and (c) immunotoxicity. Results have been discussed in the light of possible immunopotentiating and antioxidant effects of melatonin to understand the influence of oxidative stress on propoxur induced immunomodulation.

Animals↗

PubMed2006

Immunotoxicity of phosphamidon following subchronic exposure in albino rats.

Effect of subchronic doses of phosphamidon exposure on humoral and cell mediated immune (CMI) responses were studied in male albino rats using SRBC, ovalbumin and KLH as antigens. Humoral immune responses were assessed by estimating antibody titre against antigen and splenic plaque forming cells (PFC) assay. CMI responses were studied by using leucocyte migration inhibition (LMI), macrophage migration inhibition (MMI) and delayed type hypersensitivity (DTH) response. Results obtained in the present study revealed marked suppression of humoral and CMI responses in a dose dependent pattern. Hence, suppression of immune responses by phosphamidon even at subchronic doses is clearly an important aspect for its safety evaluation.

Albinism↗

PubMed2005

Insecticidal, repellent and oviposition-deterrent activity of selected essential oils against Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus.

Essential oils extracted from 10 medicinal plants were evaluated for larvicidal, adulticidal, ovicidal, oviposition-deterrent and repellent activities towards three mosquito species; Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus. The essential oils of Juniperus macropoda and Pimpinella anisum were highly effective as both larvicidal and ovicidal. The essential oil of P. anisum showed toxicity against 4th instar larvae of A. stephensi and A. aegypti with equivalent LD95 values of 115.7 microg/ml, whereas it was 149.7 microg/ml against C. quinquefasciatus larvae. Essential oils of Zingiber officinale and Rosmarinus officinalis were found to be ovicidal and repellent, respectively towards the three mosquito species. The essential oil of Cinnamomum zeylanicum resulted into highest repellent (RD95) values of 49.6, 53.9 and 44.2 mg/mat against A. stephensi, A. aegypti and C. quinquefasciatus, respectively apart from oviposition-deterrent potential.

Animals↗

PubMed2005

Bioavailable iron and heme metabolism in Plasmodium falciparum.

Iron metabolism is essential for cell function and potentially toxic because iron can catalyze oxygen radical production. Malaria-attributable anemia and iron deficiency anemia coincide as being treatable diseases in the developing world. In absolute amounts, more than 95% of Plasmodium metal biochemistry occurs in the acidic digestive vacuole where heme released from hemoglobin catabolism forms heme crystals. The antimalarial quinolines interfere with crystallization. Despite the completion of the Plasmodium genome, many 'gene gaps' exist in components of the metal pathways described in mammalian or yeast cells. Present evidence suggests that parasite bioavailable iron originates from a labile erythrocyte cytosolic pool rather than from abundant heme iron. Indeed the parasite has to make its own heme within two separate organelles, the mitochondrion and the apicomplast. Paradoxically, despite the abundance of iron within the erythrocyte, iron chelators are cytocidal to the Plasmodium parasite. Hemozoin has become a sensitive biomarker for laser desorption mass spectrometry detection of Plasmodium infection in both mice and humans.

Animals↗

PubMed2005

Chronomics of circulating plasma lipid peroxides and anti-oxidant enzymes and other related molecules in cirrhosis of liver. In the memory of late Shri Chetan Singh.

BACKGROUND: The chronome (from chronos, time, and nomos, rule; time structure) of lipid peroxidation and anti-oxidant defense mechanisms may relate to the efficacy and management of preventive and curative chronotherapy. PATIENTS AND METHODS: Thirty patients with liver cirrhosis, 25-45 years of age, and 60 age-matched clinically healthy volunteers were synchronized for 1 week with diurnal activity from about 06:00 to about 22:00 and nocturnal rest. Breakfast was around 08:30, lunch around 13:30 and dinner around 20:30. Drugs known to affect the free-radical system were not taken. Blood samples were collected at 6-h intervals for 24 h under standardized, presumably 24-h synchronized conditions. Determinations included plasma lipid peroxides, in the form of malondialdehyde (MDA), blood superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione reductase (GR) activities, and serum total protein, albumin, ascorbic acid, and uric acid concentrations. RESULTS: A marked circadian variation was demonstrated for each variable in each group by population-mean cosinor (P < 0.01). In addition to anticipated differences in overall mean value (MESOR), patients differed from healthy volunteers also in terms of their circadian pattern. CONCLUSION: Mapping the broader time structure (chronome) with age and multifrequency rhythm characteristics of antioxidants and pro-oxidants is needed for exploring their putative role as markers in the treatment and management of liver cirrhosis.

Adult↗

PubMed2005

Simultaneous determination of vincristine, vinblastine, catharanthine, and vindoline in leaves of catharanthus roseus by high-performance liquid chromatography.

A simple reversed-phase liquid chromatographic method is developed for the simultaneous quantitation of the anticancerous drugs vincristine, vinblastine, and their precursors catharanthine and vindoline using a Merck Chromolith Performance reversed-phase high-performance liquid chromatography column. A better resolution is obtained in comparison with available particulate-type C18 columns. The column provides good reproducibility and peak symmetry. Chromatography is carried isocratically with a mobile phase of acetonitrile-0.1M phosphate buffer containing 0.5% glacial acetic acid (21:79, v/v; pH 3.5) at a flow rate of 1.2 mL/min and UV detection at 254 nm. Parameters such as linearity, limits of quantitation (LOQ) and detection (LOD), precision, accuracy, recovery, and robustness are studied. The method is selective and linear for alkaloid concentration in the range 0.25 microg-25 microg/mL. The LOQ and LOD are 25, 46, 56, and 32 microg/mL and 8, 14, 18, and 10 microg/mL, respectively. The results of accuracy studies are good. Values for coefficient of variation are 2.50, 1.82, 1.33, and 1.13, respectively. The percent recovery of the alkaloids was found to be 96%, 97%, 98%, and 98%, respectively. Peak purity and homogeneity of these compounds in plant extract is studied using a photodiode-array detector. This simple and rapid method of analysis is applied for the determination of these alkaloids in a large number of leaf extracts of Catharanthus roseus..

Calibration↗

PubMed2005

Vapor-phase photo-oxidation of methanol over nanosize titanium dioxide clusters dispersed in MCM-41 host material part 1: synthesis and characterization.

Nanosize clusters of titania were dispersed in mesoporous MCM-41 silica matrix with the help of the incipient wet-impregnation route, using an isopropanol solution of titanium isopropoxide as precursor. The clusters thus formed were of pure anatase phase and their size depended upon the titania loading. In the case of low (< 15 wt %) loadings, the TiO2 particles were X-ray and laser-Raman amorphous, confirming very high dispersion. These particles were mostly of < or = 2 nm size. On the other hand, larger size clusters (2-15 nm) were present in a sample with a higher loading of approximately 21 wt %. These particles of titania, irrespective of their size, exhibited an absorbance behavior similar to that of bulk TiO2. Powder X-ray diffraction, N2-adsorption and transmission electron microscopy results showed that while smaller size particles were confined mostly inside the pore system, the larger size particles occupied the external surface of the host matrix. At the same time, the structural integrity of the host was maintained even though some deformation in the pore system was noticed in the case of the sample having highest loading. The core level X-ray photoelectron spectroscopy results revealed a + 4 valence state of Ti in all the samples. A positive binding energy shift and the increase of the width of Ti 2p peaks were observed, however, with the decrease in the particle size of supported titania crystallites, indicative of a microenvironment for surface sites that is different from that of the bulk.

Crystallization↗

PubMed2005

Vapor-phase photo-oxidation of methanol over nano-size titanium dioxide clusters dispersed in MCM-41 host material part 2: catalytic properties and surface transient species.

We report in this paper on the ultraviolet-assisted vapor-phase oxidation of methanol at room temperature, with the help of nano-size clusters of titanium dioxide dispersed in an MCM-41 silicate matrix. The surface species formed during the adsorption/oxidation of methanol and the transformation that they undergo as a result of ultraviolet irradiation were monitored using in-situ Fourier transform infrared and thermal desorption spectroscopy techniques. Parallel experiments conducted on TiO2/MCM, bulk titania, and pristine MCM-41 samples helped in identifying the individual role of titanium dioxide and host matrix in these processes. The photo-catalytic oxidation of methanol, at concentrations of 0.1 to 1.1 mol% in air, gave rise to formation of CO2 and H2O as products, for both the TiO2/MCM and bulk TiO2 samples. No such reaction occurred on titania-free MCM. Furthermore, the rate of reaction depended upon the TiO2 content of a sample and also on the concentration of methanol in reaction mixture. Thus, the rate of conversion increased progressively with the increase in TiO2 loading from 5 to 21 wt% in TiO2/MCM samples, particularly for the experiments with high concentration of methanol. For low methanol concentration (0.1 mol%) in air, the effect of titania content in MCM was very small. The specific activity (per g of titania) of a sample, on the other hand, showed an inverse relationship with the loading of titanium dioxide in a sample. Infrared and temperature-programmed desorption results revealed that the mode of CH3OH adsorption and the reactivity of the transient species formed during the oxidation process were independent of the size of dispersed titania particles. Thus, the particles of approximately 2-6 nm size, present in TiO2/MCM, exhibited a chemisorption behavior similar to that of the bulk titania. The results of the present study provide strong evidence that the hydroxyl groups, both on the host matrix and at the titania sites, participate independently in the formation of methoxyl groups and at the same time promote the heterogeneous photo-catalytic oxidation of methanol molecules via formation of transient formate groups. Our results also show that the effect of titania crystallite size in the photo-catalytic properties relate mainly to the larger surface area and hence to the enhanced number of chemisorption sites, rather than to the changes in electronic properties.

Catalysis↗

PubMed2005

Study of bone marrow abnormalities in patients with HIV disease.

AIM: Present work was carried out to study the bone marrow abnormalities in patients with HIV/AIDS and to find their association with peripheral hematological abnormalities. METHODS: Seventy four patients of HIV/AIDS were included in the study. The patients had anemia, leucopenia, thrombocytopenia or pyrexia of unknown origin (PUO) as indications for bone marrow examination. A complete blood count, relevant biochemical investigations, HIV RNA load and CD4 positive lymphocyte counts were done, besides a thorough history and clinical examination. HIV positive patients were classified as those having AIDS and those without AIDS according to NACO criteria. RESULTS: Majority of patients (72.9%) had AIDS. Bone marrow was normocellular in 78.95% of non-AIDS and 74.55% of AIDS, hypocellular in 5.26% of non-AIDS and 7.27% of AIDS, hypercellular in 15.79% of non-AIDS and 18.18 % of AIDS patients. Myelodysplasia was present in 21.05% of non AIDS and 36.46% of AIDS and the most common series affected was granulocytic (15.79% of total in non-AIDS and 30.9% in AIDS). Dysplasia was statistically significantly associated with lower CD4 count (p = 0.031) and anemia (p = 0.013). Myelodysplasia was apparent even before patients developed anemia (16.67%). Increased plasma cells in bone marrow were observed in 57.89% of non-AIDS and 65.45% of AIDS, whereas decreased lymphoid cells were seen in 36.84% of non AIDS and 60.00% of AIDS patients. CONCLUSIONS: Myelodysplasia is found in 32.43% of cases of HIV/AIDS and is more common in AIDS than in non AIDS patients. Granulocytic series is most commonly associated with evidence of dysplasia. Myelodysplasia is more common in patients with CD4 count < 200/microl and in patients with anemia. 54.05% of patients had decreased lymphoid cells in bone marrow and it was more commonly seen in AIDS than in non AIDS.

AIDS-Related Complex↗

PubMed2005

Bone marrow abnormalities in HIV disease.

Bone marrow abnormalities are frequently observed in HIV infected individuals at all stages of the disease. The most common abnormal finding is dysplasia affecting one or more cell lines. Erythroid dysplasia is the most common type of dysplasia and is recognized in over 50% of HIV infected patients, abnormal granulocytic and megakaryocytic development is encountered in one-third of patients. Plasma cells are strikingly increased in bone marrow of HIV infected patients. It may represent a physiological response to antigenic stimulation by viruses, other infective agents or secondary to dysregulated B-cell proliferation due to HIV. Herein we present a review discussing the various bone marrow abnormalities associated with the HIV disease.

AIDS-Related Complex↗

PubMed2004

Arjunetin from Terminalia arjuna as an insect feeding-deterrent and growth inhibitor.

Crude ethanolic extract of the stem bark of Terminalia arjuna (Combretaceae) and its three compounds namely arjunic acid, arjungenin and arjunetin were evaluated for antifeedant, growth inhibitory and oviposition-deterrent activities against a lepidopterous insect Spilarctia obliqua. The compound arjunetin showed highest growth inhibitory and feeding-deterrent properties with a growth inhibition (GI(50)) and feeding-inhibition (FD(50)) of 188.5 and 287.1 micro g/g diet respectively. Oviposition bioassays indicated no oviposition-deterrence in any of the compounds tested. The structure-activity relationship study indicated the importance of a glycosidation linkage in arjunetin.

Animals↗

PubMed2004

Comparative effectiveness of cattle manure, poultry manure, phosphocompost and fertilizer-NPK on three cropping systems in vertisols of semi-arid tropics. I. Crop yields and system performance.

A field experiment was conducted on deep vertisols of Bhopal, India to evaluate the manural potential of three organic manures: farmyard manure (FYM), poultry manure (PM), phosphocompost (PC) vis-a-vis 0%, 75% and 100% recommended dose of fertilizer-NPK and to find out the most productive cropping system at various combinations of organic manures and chemical fertilizers. The seed yield of intercrop soybean (population converted to 100%) was 8.7% less than sole soybean whereas the grain yield of intercrop sorghum was 9.5% more than that of sole sorghum. However, the productivity in terms of soybean equivalent yield (SEY) was relatively high in intercropping system. The increasing NPK dose from 0% to 100% significantly improved SEY in sole sorghum and soybean/sorghum intercropping system and the integrated use of organics and inorganics recorded significantly more SEY than inorganics. The effect of nutrient management followed the order; 75% NPK + 5 t FYM ha(-1) > 75% NPK + 1.5 t PM ha(-1) > 75% NPK + 5 t PC ha(-1) > 100% NPK. Sorghum, both as sole and intercrop, responded more to PM while soybean to FYM. Application of 75% NPK in combination with PM or FYM or PC to preceding rainy season crops (soybean and sorghum) and 75% NPK to wheat produced significantly higher grain yield of wheat than those in inorganics and control indicating noticeable residual effect on the succeeding wheat crop and saving of 25% fertilizer-NPK. The effect of PC on rainy season crops was not as prominent as those of FYM and PM, but its residual effect on grain yield of wheat was comparable to those two organic manures. Among the cropping systems, soybean as preceding crop recorded the highest seed yield of wheat and was on a par with that of soybean/sorghum intercropping system. The yield of wheat following sorghum was the lowest. The total system productivity (TSP) was the highest in sorghum + soybean-wheat system and the lowest in the soybean-wheat system.

Agriculture↗

PubMed2004

Enrichment and identification of bacteria capable of reducing chemical oxygen demand of anaerobically treated molasses spent wash.

AIMS: The aim of this study was to isolate and identify bacterial strains capable of using recalcitrant compounds of molasses spent wash as sole carbon source from the soils of abandoned sites of distillery effluent discharge and characterize their ability of reducing the chemical oxygen demand (COD) of the spent wash. METHODS AND RESULTS: The isolates were grouped into six haplotypes by amplified ribosomal DNA restriction analysis (ARDRA) and BOX-PCR. The phylogenetic position of the representatives of the six main haplotypes strains was determined by 16S rDNA sequencing. They showed maximum similarity to six genera viz. Pseudomonas, Enterobacter, Stenotrophomonas, Aeromonas, Acinetobacter and Klebsiella. The extent of COD (44%) reduced collectively by the six strains was equal to that reduced individually by Aeromonas, Acinetobacter, Pseudomonas and Enterobacter. With spent wash as sole carbon source, the COD reducing strains grew faster at 37 degrees C than 30 degrees C. CONCLUSIONS: Bacterial strains capable of degrading some of the recalcitrant compounds of anaerobically digested molasses spent wash can be isolated from the soils of abandoned sites of distillery effluent discharge. Biostimulation of these bacteria, which can degrade 44% of the carbon compounds of anaerobically digested molasses spent wash can be achieved by nitrogen fertilization and relatively higher temperature. SIGNIFICANCE AND IMPACT OF THE STUDY: Supplementation of nitrogen source and controlling the temperature can be used in evolving strategies for in situ bioremediation of anaerobically digested spent wash from distilleries.

Bacteria↗

PubMed2004

Molecular diversity of tannic acid degrading bacteria isolated from tannery soil.

AIMS: The aim of this study was to enrich and isolate bacteria from a tannery soil that were capable of utilizing tannic acid and gallic acid as sole source of carbon aerobically, and to characterize their diversity in order to identify efficient strains that can be used for tannin bioremediation. METHODS AND RESULTS: Bacterial strains were isolated after enrichment in minimal medium with tannic acid or gallic acid as sole carbon source. Polymerase chain reaction (PCR) restricted fragment length polymorphism of 16S rDNA [amplified ribosomal DNA restriction analysis (ARDRA)] and BOX-PCR was used to characterize their diversity. Two strains showing relatively high efficiency in degrading tannic acid and gallic acid were identified on the basis of carbon source utilization pattern (BIOLOG) and 16S rDNA sequence. CONCLUSIONS: Bacterial strains capable of degrading tannic acid and gallic acid could be grouped into six and seven clusters on the basis of ARDRA and BOX-PCR, respectively. On the basis of 16S rDNA sequence, the most efficient isolate degrading tannic acid belonged to Pseudomonas citronellolis, whereas the most efficient gallic acid degrader showed maximum phylogenetic relatedness to P. plecoglossicida. SIGNIFICANCE AND IMPACT OF THE STUDY: Aerobic tannic acid degraders such as the two strains isolated in this study can be used for tannin bioremediation, and in the study of genes involved in the production of tannase, an industrially important enzyme.

Benzoates↗

PubMed2004

HIV disease presenting as parotid lymphoepithelial cysts: a presumptive diagnosis of diffuse infiltrative lymphocytic syndrome (DILS).

Diffuse infiltrative lymphocytic syndrome (DILS), is a rare manifestation of human immunodeficiency virus (HIV) disease which is characterized by a diffuse visceral CD8 lymphocytic infiltration, a persistent CD8 lymphocytosis, bilateral parotid swelling and cervical lymphadenopathy. We describe a case of a HIV positive female, who had bilateral parotid swelling and CD8 lymphocytosis, to illustrate this rare clinical entity.

Adult↗