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Biomedical subjects

S Nanda

Publications and source records attributed to S Nanda.

At least 19 recordsLinked to original sources
PubMed2003

Cross-section measurement of charged-pion photoproduction from hydrogen and deuterium.

We have measured the differential cross section for the gamman-->pi(-)p and gammap-->pi(+)n reactions at theta(c.m.)=90 degrees in the photon energy range from 1.1 to 5.5 GeV at Jefferson Lab (JLab). The data at E(gamma) greater, similar 3.3 GeV exhibit a global scaling behavior for both pi(-) and pi(+) photoproduction, consistent with the constituent counting rule and the existing pi(+) photoproduction data. Possible oscillations around the scaling value are suggested by these new data. The data show enhancement in the scaled cross section at a center-of-mass energy near 2.2 GeV. The cross section ratio of exclusive pi(-) to pi(+) photoproduction at high energy is consistent with the prediction based on one-hard-gluon-exchange diagrams.

Journal Article↗
PubMed2002

Efficient enantioselective reduction of ketones with Daucus carota root.

A novel and efficient reduction of various prochiral ketones such as acetopehones, alpha-azido aryl ketones, beta-ketoesters, and aliphatic acyclic and cyclic ketones to the corresponding optically acive secondary alcohols with moderate to excellent chemical yield was achieved by using Daucus carota, root plant cells under extremely mild and environmentally benign conditions in aqueous medium, has been described. Many of these optically active alcohols are the potential chiral building blocks for the synthesis of pharmaceutically important molecules and asymmetric chiral ligands. Hence, this biocatalytic approach is found to be the most suitable for the preparation of a wide range of chiral alcohols and gave inspiration for the development of a new biotechnological process.

Acetophenones↗
PubMed2001

Dynamics of the 16O(e, e'p) reaction at high missing energies.

We measured the cross section and response functions for the quasielastic 16O(e,e'p) reaction for missing energies 25< or =E(m)< or =120 MeV at missing momenta P(m)< or =340 MeV/c. For 25<E(m)<50 MeV and P(m) approximately 60 MeV/c, the reaction is dominated by a single 1s(1/2) proton knockout. At larger P(m), the single-particle aspects are increasingly masked by more complicated processes. Calculations which include pion exchange currents, isobar currents, and short-range correlations account for the shape and the transversity, but for only half of the magnitude of the measured cross section.

Journal Article↗
PubMed2001

Short- and long-term effects of fraternity and sorority membership on heavy drinking: a social norms perspective.

This study sought to determine whether the well-established relation between fraternity/sorority (Greek) membership and heavy alcohol use persists beyond the college years and whether some common third variables might account for the relation between Greek status and heavy drinking. During each of 4 years of college and 1 additional year, young adults (N = 319) completed measures of alcohol use, personality, alcohol expectancies, and environmental influences on drinking. Throughout the college years, Greeks consistently drank more heavily than non-Greeks. Statistically controlling for previous alcohol use did not eliminate this effect. However, Greek status did not predict postcollege heavy drinking levels. Also, perceived peer norms for heavy drinking mediated the relation between Greek affiliation and heavy alcohol use. Results are discussed in terms of situational determinants of heavy alcohol involvement in young adults.

Adult↗
PubMed1999

Captopril-induced toxic epidermal necrolysis and agranulocytosis successfully treated with granulocyte colony-stimulating factor.

Captopril-induced bone marrow suppression is rare, except in certain high-risk patient populations. Severe exfoliative rashes have also been associated with captopril, but a combined presentation of toxic epidermal necrolysis and agranulocytosis has not been previously described. We report an unusual case of captopril-induced toxic epidermal necrolysis with agranulocytosis in a patient with no known risk factors. The bone marrow suppression was successfully treated using granulocyte colony-stimulating factor (G-CSF), and the white blood cell (WBC) count recovered within 3 days after starting therapy. This case underscores the early experience with captopril, which showed a strong correlation between high doses used to treat hypertension and bone marrow suppression.

Agranulocytosis↗
PubMed1998

Multiple promoters direct stimulus and temporal specific expression of brain-derived neurotrophic factor in the somatosensory cortex.

Neuronal activity rapidly induces expression of brain-derived neurotrophic factor (BDNF) in the adult rat cortex. The rat BDNF gene has four differentially regulated promoters, each of which produce an mRNA containing a unique 5' exon (I-IV) and a common 3' exon (V) that encodes the mature BDNF protein. The present study used an exon-specific RT-PCR analysis to determine the time course of the induction from both seizures and whisker stimulation. Our data show that specific promoters are utilized at different stages of the activity-dependent induction of the BDNF gene. Furthermore, the data show a differential utilization of the four promoters following a specific stimulus.

Animals↗
PubMed1998

Massive mature solid teratoma of the ovary with gliomatosis peritonei.

Glial implants on peritoneum and omentum may occur with mature solid teratoma of the ovary (gliomatosis peritonei). The case of a 17-year-old girl is presented, who had a massive solid ovarian teratoma with glial implants on visceral peritoneum and omentum. The massive size of the tumour posed difficulty in diagnosis. CT demonstrated a large teratoma. At laparotomy, the seedlings were initially thought to be evidence of malignancy and hysterectomy was offered which was refused by the parents. Oophorectomy was performed and the benign nature of the tumour and implants was seen on histopathology. It is important to recognize the benign nature of glial seedlings in such cases to avoid unnecessary extensive surgery.

Adolescent↗
PubMed1997

Nonunion of uterine incision: a rare cause of secondary postpartum haemorrhage: a report of 2 cases.

Secondary postpartum haemorrhage after Caesarean section due to non-union of the uterine incision is an unusual complication. Two women who had had lower segment Caesarean section for placenta praevia presented after 2 and 3 weeks respectively with shock due to massive postpartum haemorrhage. The uterine scars had not healed in both of these women who were managed by emergency subtotal hysterectomy.

Adult↗
PubMed1996

Risk analysis in the valuation of medical practices.

Risk analysis techniques used in valuing medical practices are discussed. Employing these techniques provides superior information to the analyst than using a single estimate for uncertain variables. Examples of scenario analysis, sensitivity analysis, and simulation are presented. These tools can be easily implemented with spreadsheet software.

Computer Simulation↗
PubMed1995

High-resolution magnetic resonance imaging evaluation of blood-retinal barrier integrity following transscleral diode laser treatment.

OBJECTIVE: To compare the effects of contact transscleral diode laser treatment and retinal cryotherapy on blood-retinal barrier integrity with the use of high-resolution magnetic resonance imaging techniques with constant infusion of gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA). METHODS: Transscleral diode laser photocoagulation and retinal cryotherapy were used to treat equivalent areas of the inferior retinal periphery of pigmented rabbits. Magnetic resonance imaging time-course studies with measurement of signal enhancements due to Gd-DTPA leakage were conducted 2 and 15 days following treatment. RESULTS: Two days following treatment, cryotherapy-treated eyes exhibited a mean (+/- SD) effective Gd-DTPA permeability coefficient of 4.6 +/- 0.8 x 10(-6) cm/s; in comparison, diode laser-treated eyes exhibited 1.6 x 1.4 x 10(-6) cm/s effective permeability. Significant decreases in the effective permeability were also noted 15 days after treatment in both groups. CONCLUSIONS: Transscleral contact probe diode laser photocoagulation induces less disruption of the blood-retinal barrier than does conventional cryotherapy. In addition, the continuous infusion method of Gd-DTPA delivery is a reliable and easily interpretable alternative to the commonly used bolus injection approach.

Animals↗
PubMed1995

Biochemical, neuropathological and behavioral studies in hens induced by acute exposure of tri-ortho-cresyl phosphate.

A "hen model" or organophosphorus induced delayed neuropathy (OPIDN) has been developed using white leghorn exposed acutely to one of five dosages of tri-ortho-cresyl phosphate (TOCP), between 300 to 700 mg/Kg. Neuropathy target esterase was studied in brain and peripheral nerve 24 and 48 hrs following exposure. Behavioral symptoms abnormality was assessed from days 1 through 20 after exposure using a 7 point rating scale and neuropathological examination was conducted on sample collected from animals on days 0, 7, 14 and 21. Neuropathological abnormalities were indicated by damage scores between 0 (no damage) and 4 (gliosis of brain tissue, myelin loss, appearance of axonal foci etc and more than 55% degeneration of peripheral nerve fibres). TOCP (600 and 700 mg/Kg, orally) was able to inhibit NTE more than 75% in brain and peripheral nerves. TOCP at the same dosage was also capable of resulting maximal levels of neuropathological score at 4. After exposure to doses weight loss was observed abruptly in a greater extent at the beginning leading to a change in weight gain till the end of the experiment. Behavioral signs were also dose dependent. Symptoms (gain abnormality, ataxia, paresis) were noted on the early stage of experiment. Inhibition of NTE was 65% could not be reached in hens given TOCP without causing lethality and no significant ataxia or lesions developed in those birds. Behavioral signs were also observed to be late onset. These data indicate that more than 75% inhibition of peripheral nerve NTE after 24 hr exposure was predictive of severe behavioral abnormalities and pathology in the hen whereas less peripheral NTE inhibition was indicative of less severe behavioral abnormalities and a lower score for neuropathological damage.

Animals↗
PubMed1995

Vesicovaginal fistulae: a 12-year study.

Repairs in 49 cases of vesicovaginal fistulae were performed during the last 12 years. Obstetric cause for vesicovaginal fistulae was noted in 81.63% cases and the most important being obstructed labour (73.46% cases). Repair was successful in 71.42% cases. Factors favourable for success were a non-obstetric fistula, small size fistula (< 10 mm) and absence of fibrosis. Repair operations were performed mainly by vaginal flap technique. The fistulous track was not excised. Polyglactin suture gave the best results.

Adolescent↗
PubMed1994

Tri-ortho-cresyl phosphate induced neurotarget esterase inhibition in brain and peripheral nerve effectively monitored by lymphocytes.

Tri-ortho-cresyl phosphate ester (TOCP: 10-100 mg/kg)--an organophosphorus compound (OP) inhibited brain, peripheral nerve and lymphocyte neurotarget esterase activities in a dose related and time-dependent manner. There was a good correlation of inhibition between brain, peripheral nerve and lymphocyte tissues taken from adult hens treated with 3 different doses of TOCP and sacrificed 24 and 48 hr after exposure. The results suggest that lymphocyte can effectively monitor OP compounds for investigating inhibition of neurotarget esterase activity in brain and peripheral nerve tissues.

Animals↗