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Biomedical subjects

V K Srivastava

Publications and source records attributed to V K Srivastava.

At least 19 recordsLinked to original sources
PubMed1999

Effects of ethanol on intraovarian nitric oxide production in the prepubertal rat.

Nitric oxide (NO) has been shown to contribute to ovarian development and function. In non-ovarian tissues NO can be altered by ethanol (ETOH), a drug considered to be a gonadal toxin in men as well as male and female rats. The present study was undertaken to determine if some of the detrimental effects of chronic ETOH exposure on prepubertal ovarian function could be due to ETOH-induced alterations in the intraovarian NO system. Rats were implanted with intragastric cannulae on day 24 and began receiving control or ETOH diets on day 29. All rats were killed on day 34, determined to be in the late juvenile stage of development, and their ovaries and blood were collected. We analyzed the expression of the two constitutive forms of nitric oxide synthase (NOS), i.e. neuronal (n) NOS and endothelial (e) NOS, as well as the inducible (i) form of NOS protein in the ovaries of control and ETOH-treated rats by Western immunoblotting. Results demonstrate that eNOS protein increased markedly (P<0.02; 140 kDa) in ETOH-treated rats compared with controls. ETOH treatment did not alter the protein expression of nNOS (155 kDa) and only slightly increased that of iNOS (130 kDa). We also assessed NOS activity as determined by nitrite accumulation and by the conversion of L-[14C]arginine to L-[14C]citrulline. In this regard, the ETOH-treated animals showed an increase in ovarian nitrite generation (P<0.05), as well as an increase in ovarian citrulline formation (P<0.0001), when compared with control animals. Along with the above described ETOH-induced increases in ovarian eNOS and NO activity, the serum levels of estradiol were concomitantly suppressed (P<0.001) in the ETOH-treated rats. These results demonstrate for the first time the ETOH-induced changes in the prepubertal ovarian NO/NOS system, and suggest that these alterations contribute to the detrimental actions of the drug on prepubertal ovarian development and function.

Animals↗
PubMed1999

Effects of ethanol on the intraovarian insulin-like growth factor-1 system in the prepubertal rat.

Insulin-like growth factor-1 (IGF-1) is considered to play an important role during ovarian development and function. Because ethanol (ETOH) is a gonadal toxin in men, as well as male and female rats, we hypothesized that this drug may be having detrimental effects in the ovary by altering the intraovarian actions of IGF-1. In support of this notion, the present study was undertaken to examine the chronic effects of ETOH on the ovarian IGF-1 system in prepubertal female rats. Each rat was implanted with a gastric cannula on day 24 and began receiving either a control or ETOH liquid diet on day 29. The animals were killed on day 34, confirmed to be in the late juvenile stage of development, and their ovaries and blood were collected. Using an RNase protection assay, we determined the expression of mRNAs encoding IGF-1 and the Type 1 IGF receptor in the ovaries of control and ETOH-treated rats. Results indicate that the ETOH-treated rats showed an increase in the ovarian expression of IGF-1a (p < 0.0001) and IGF-1b (p < 0.001) mRNA, the two alternatively spliced forms of the IGF-1 gene. Conversely, ovarian IGF-1 protein levels were depressed (p < 0.05) in ETOH-treated rats as determined by radioimmunoassay. Furthermore, ETOH-treated rats showed a decrease (p < 0.01) in the expression of Type-1 IGF receptor mRNA with a subsequent decrease (p < 0.05) in the ovarian levels of IGF-1 receptor protein, as determined by Western blot analysis. Also, using Western immunoblotting, we determined increases in immunoreactive IGF-binding proteins-3 (p < 0.05) and 5 (p < 0.01), but not 4, in ETOH-treated rats as compared with controls. Furthermore, we observed a concomitant decrease (p < 0.01) in the serum levels of estradiol. These results demonstrate for the first time that chronic ETOH administration is capable of altering the prepubertal intraovarian IGF-1 signaling system. We suggest that, at least in part, these effects contribute to altered prepubertal ovarian function after chronic exposure to ETOH.

Animals↗
PubMed1998

Synthesis and anti-inflammatory activity of some potential cyclic phenothiazines.

Some new schiff's bases (IVa-IVe), thiazolidinones (Va-Ve), delta 2-triazolines (VIa-VIe) and formazans (VIIa-VIIe) of 2-chlorophenothiazine have been synthesized and screened against Carrageenin induced oedema in albino rats. Some compounds of the series have shown promising activity. The most active compound is 2-chloro-10[5-(2-fluorophenyl-2-oxo-4 thiazolidin-1-yl)-amino acetyl] phenothiazine was found to be most potent. This compound (Vb) was further evaluated in detail and compared with phenylbutazone for its relative anti inflammatory potency (ED50), ulcerogenic liabilities (UD50) and acute toxicity (ALD50). It was found to be almost comparable to phenylbutazone as regards anti-inflammatory activity was concerned but and minimum ulcerogenic liability and cardiovascular effects. Hence, it seems promising as an anti-inflammatory agent in our preliminary studies.

Administration, Oral↗
PubMed1997

Biting behaviour and biting rhythm of potential Japanese encephalitis vectors in Assam.

Studies on biting behaviour and biting cycles of medically important mosquitoes were carried out in Madhupur village and Tarajan tea estate of upper Assam. Collections were made off human baits outdoors and indoors and off cattle bait outdoors from August 1991 to July 1992. Human bait collections were performed using the 'stationary direct bait' technique. A total of 9,072 adult host seeking female mosquitoes representing 26 species and 5 genera were collected off baits of which 36.9% were collected off human baits and the rest from cattle. All mosquitoes were primarily zoophilic, although significant numbers were collected biting man outdoors. Biting preferences of important Japanese encephalitis (JE) vectors for man and cattle were studied using outdoor man:outdoor cattle ratio (attraction ratio = AR). Culex quinquefasciatus was attracted towards human baits the most (AR = 8.1:1), followed by Cx. bitaeniorhynchus (AR = 1.6:1) and Mansonia annulifera (AR = 1.3.1). The hourly biting activity of important JE vectors throughout the night on two bait types was also studied using three point moving averages. Hierarchical agglomerative cluster analysis was used to compare and classify mosquitoes on the basis of their similarity in biting rhythms.

Animals↗
PubMed1996

Differential expression of DNA polymerase alpha in normal and transformed human fibroblasts.

The expression of DNA polymerase alpha (pol alpha) was studied in human fibroblast lines W138 (fetal lung) and GM3529 (skin, established from a 66 yr old donor), and their Simian virus 40 (SV40) large tumor antigen (TAg)-transformed corollaries, 2RA and 2-1 respectively. Both SV40-transformed and pSV3.neo (SV40-derived plasmid)-transformed cells express TAg, a virally encoded protein not expressed by the normal parent cell lines. Northern blot hybridization studies showed increased recovery of pol alpha mRNA from transformed cells compared with normal cells. This increase was correlated with increased pol alpha mRNA transcription as determined by nuclear run-on assays. Northern blot analyses also showed an increase in the instability of translationally active pol alpha mRNA in transformed cells. The results suggest that TAg, in addition to its dsDNA binding, pol alpha binding, retinoblastoma protein binding and helicase activities, may be involved either directly or indirectly in regulation of the steady state mRNA levels of pol alpha at the transcriptional level in both fetal and aged donor-derived transformed fibroblasts.

Aged↗
PubMed1996

Effects of oral lithium on the action of various C.N.S. active drugs.

Effects of prolonged lithium administration was seen on the action of various psychoactive drugs in animals. Apomorphine induced pecking in pigeons increased significantly by lithium treatment for 14 days, from 1445.3 +/- 202.5 in control to 2785.8 +/- 205.8 in Gp. B. Haloperidol-induced catalepsy score in albino rats increased significantly following chronic lithium treatment compared to control. Chlorpromazine-induced hypothermia in rabbits was immediate but transient, while in lithium treated rabbits induction of hypothermia was delayed, sustained and of greater magnitude. This action of lithium may be mediated by increasing the permeability of blood-brain barrier, or enhancing the sensitivity of alpha-adrenoceptors in brain.

Administration, Oral↗
PubMed1996

Albendazole therapy in orbital cysticercosis.

A patient with orbital cysticercosis is being presented, where albendazole therapy was successfully used. Serial CT scans of the lesions showed definite signs of resolution. The role of albendazole therapy in cysticercosis has been discussed. The relevant literature has been reviewed in brief.

Adult↗
PubMed1996

Effect of arteether alpha/beta on uncomplicated falciparum malaria cases in Upper Assam.

Thirty patients of uncomplicated Plasmodium falciparum malaria completed a clinical trial of arteether alpha/beta conducted in a malaria endemic tea garden of district Dibrugarh, Assam. Arteether was given intramuscularly in once a day dose of 150 mg for three consecutive days. The cure rate was 100 per cent with mean fever and parasite clearance time of 42.4 +/- 17.5 and 37.6 +/- 13.6 h respectively. Recrudescence/reinfection rate was 6.7 per cent. Palpable spleens of twenty out of twenty one cases on day 0 became non palpable within 28 days. Following the treatment, percentage of hemoglobin improved marginally with no remarkable change in total and differential leucocyte count. Arteether alpha/beta, besides being a potent and fast acting schizontocidal drug, also exhibited gametocytocidal action on P. falciparum.

Adolescent↗
PubMed1996

Correlation between degree of protection and humoral antibody response in hamsters immunized with somatic and excretory secretory antigens of Ancylostoma ceylanicum.

Correlation between the degree of protection and induced serum antibody response in hamsters immunized with somatic and excretory-secretory (ES) antigens of adult. A. ceylanicum was investigated. Hamsters were immunized with non purified and Sephadex G-200 fractions (F1, F2 and F3) of somatic and ES antigens. The degree of protection was assessed in terms of percent worm reduction compared to controls against challenge infection. Induced humoral antibody response was determined by ELISA. Both somatic and ES antigens had shown moderate to significant protection but the latter was found more immunogenic as highest level of protection (67.02%) was achieved by these antigens. Humoral antibody was found highly elevated in animals immunized with protective doses of somatic and ES antigens. The maximum serum antibody titer i.e. 1:3200 was noticed in animals immunized with high protective dose (64.59% protection) of fraction F1 of ES antigens. Antibody titer correspond to the degree of protection and a positive correlation between induced humoral antibodies and protection level was established.

Ancylostoma↗
PubMed1996

Vector incrimination in Tamulpur primary health centre, district Nalbari, lower Assam during malaria outbreak 1995.

A widespread outbreak of malaria occurred in different districts of lower Assam in April, 1995. Entomological investigations were carried out in Primary Health Centre Tamulpur, the worst hit area of Nalbari district. Of the nine anopheline species collected, Anopheles minimus was incriminated as the malaria vector with sporozoite rate of 6.5 per cent. The slow moving streamlets were identified as the sole breeding places of An. minimus.

Animals↗
PubMed1996

Injury to anterior optic pathways.

Fourteen patients with injury to the anterior optic pathways have been presented and analysed. Their clinical profile, radiological data and problems involved therein have been discussed. Since an expectant policy has been the rule so far, an attempt has been made to define the role of surgery in such cases.

Adolescent↗
PubMed1996

Role of some environmental factors in modulating seasonal abundance of potential Japanese encephalitis vectors in Assam, India.

Temporal changes in the abundance of host-seeking, potential Japanese encephalitis (JE) vector mosquitos and the role of some ecological factors that are modulating the abundance of vector mosquitos were studied. Vector surveillance was conducted for one year in 4 JE prone villages of Dibrugarh, Assam. Among potential JE vectors, the most abundant mosquito was Culex vishnui s.s. comprising about 22.32%. Maximum density of the mosquito was found during the month of April and another peak was observed in the month of September. The influence of meteorological factors on the abundance of JE vectors was found to vary from species to species. The final multiple regression equations (after variables were selected using STEPWISE procedure) consisted of a combination of linear, quadratic, cubic and interactive ecological variables and accounted for 25-98% of the variations in the abundance of JE vector mosquitos. Complex interactions among environmental factors, such as minimum and maximum temperature, rainfall and flood level are involved in modulating the seasonal abundance of mosquitos. A time lag is involved before a cause and effect relationship is established between environmental parameters (independent variables) and entomological variables (dependent variables). Inundation caused by flooding is favorable for mansonioid mosquito species whereas it has an adverse effect on non-mansonioid mosquito species.

Animals↗
PubMed1995

Wound healing in trophic ulcers in spina bifida patients.

Eight cases of tethered conus medullaris with trophic ulcers in the foot in spina bifida patients are presented. The ulcers, which had remained unhealed for 1 to 8 years prior to surgery, healed in a few weeks after the tethered conus was released. The possibility of some neurotrophic factor in wound healing is suggested.

Adolescent↗
PubMed1995

Synthesis and pharmacological evaluation of 1,2,4-triazine and its congeners.

3-[Mercapto]-n-propanoxy/methyl-ethanoxy branched chain in 5,6-Diphenyl- 1,2,4-triazine were condensed with O-phenylene diamine or O- aminophenol or o-aminothiophenol. The carboxylic groups of the synthesized compounds were cyclised to yield imidazoles, oxazoles and thiazoles. They were screened for their anti-inflammatory response in albino rats against carrageenin induced paw oedema. The active compounds were also evaluated for their ED50 value in albino rats and analgesic activity in albino mice. The compounds exhibited significant anti-inflammatory activity also showed marked protection against aconitine induced writhing response. The potent compounds showed high LD50 values.

Animals↗