Search PubMed⌕ Search

Biomedical subjects

S Seth

Publications and source records attributed to S Seth.

At least 37 records · Page 2Linked to original sources
PubMed1995

Comparative bioavailability of two brands of norfloxacin.

Twelve adult healthy volunteers participated on two occasions in a cross-over study with an interval of 30 days. The bioavailability of norfloxacin 400 mg administered as single oral dose was compared in an Indian preparation A (Torrent) and imported preparation B (Merck Sharp and Dohme (MSD), USA). Plasma was separated from the blood and stored at -20 degrees C for analysis by High Performance Liquid Chromatography. Time taken to achieve mean peak plasma concentration (Tmax) was 2.00 +/- 0.74 hours in case of Torrent (A) and 1.70 +/- 0.49 hours in case of Merck Sharp and Dohme, USA (B). The maximum plasma concentration (Cmax) ranged from 1.60 to 2.87 ug/ml in Torrent (A) and 1.18 to 2.28 ug/ml in case of MSD (B). Area under plasma concentration curve (AUCO-12hr) was 12.70 +/- 3.2 ug/ml/hour for 'A' and 14.80 +/- 2.80 ug/ml/hr for 'B'. Elimination half life (t1/2) for Torrent (A) was 9.25 +/- 5.10 hours and for MSD (B) it was 12.05 +/- 1.05 hours. There was no significant difference in the pharmacokinetic parameters between the two brands (Student's 't' test). Increased elimination half life and large bioavailability (AUC) with both the preparations in the present study suggest the need to be cautious while treating patients with renal problems and to use lower doses in Indian population to achieve desirable kinetics of norfloxacin.

Administration, Oral↗
PubMed1995

Comparative bioavailability of two brands of ciprofloxacin.

Twelve adult healthy volunteers participated on two occasions in a cross-over study with an interval of 30 days. The bioavailability of ciprofloxacin 500 mg administered as single oral dose was compared in preparation A (Indian, Torrent) and preparation B (Imported, Bayer). The drug was administered early morning on an empty stomach. Blood samples were collected at 1/2,1,2,4,6,8,12 and 24 hours. Plasma levels of ciprofloxacin were determined by HPLC. Time taken to achieve peak plasma concentration (Tmax) was 2 hours (A) and 1.67 +/- 0.49 hours (B). Maximum plasma concentration (Cmax) ranged from 1.8 to 5.1 ug/ml (mean 3.08 +/- 0.99 ug/ml) for 'A' and 2.08 to 5.5 mu g/ml (mean 3.58 +/- 1.37 mu g/me for 'B'. Area under plasma concentration time curve ranged from 30.91 to 118.27 ug/ml/hr (mean 59.97 +/- 26.68 ug/ml/hr) in 'A' and 36.52 to 108.05 (mean 62.80 +/- 22.33 ug/ml/hr) in 'B' which is more than reported in Western literature. Large bioavailability of ciprofloxacin in the present study suggests the need to be cautious while treating patients with renal problems and to use lower doses in Indian patients to achieve desirable results. However, there was no significant difference in the pharmacokinetic parameters between the two brands (Paired 't' test and Wilcoxon Sign Rank test). It is therefore, concluded that both the preparations are comparable in terms of bioavailability.

Administration, Oral↗
PubMed1994

Alteration in blood gases in tetanus.

Tetanus is an important cause of patient mortality. Hypoxia is an important determinant of poor prognosis in tetanus. Oxygen saturation (Sa02) determines effectiveness of muscle relaxants. We performed arterial blood gas (ABG) studies in 20 patients with tetanus and 20 controls. All patients had hypoxemia and metabolic acidosis at admission. The mortality rate in patients with admission PaO2 < 70mm Hg was higher compared to those with PaO2 > 70mm Hg (P < 0.01). Patient with pH < 7.2 had higher mortality compared to those with pH > 7.2 (p < 0.05). Severe hypoxemia and severe metabolic acidosis connoted poor prognosis.

Acidosis↗
PubMed1993

Effect of atenolol and labetalol on serum lipids.

Adverse alterations in lipid profile suggesting higher atherogenicity were observed following 12 weeks treatment with atenolol in patients of hypertension. No significant alterations in lipid profile were observed with labetalol therapy.

Atenolol↗
PubMed1992

Evidence for verapamil-induced functional inhibition of noradrenergic neurotransmission in vivo.

Contractions of the cat nictitating membrane have been used to explore the effects of calcium channel blockers on neurotransmission in vivo, by comparing the effects of verapamil and nifedipine on contractions of nictitating membrane following either electrical stimulation of the superior cervical ganglion or intravenous injection of the alpha-adrenoceptor agonist phenylephrine. Verapamil (0.3, 0.6 and 1.2 mg/kg, iv) produced a dose related and reversible inhibition of stimulation induced contractions but did not affect phenylephrine responses of nictitating membrane. Intravenous nifedipine (10, 20 and 40 micrograms/kg) produced inconsistent effects on both stimulation- and phenylephrine-induced contractions of the nictitating membrane. Thus only verapamil appears to selectively affect noradrenergic neurotransmission in this model, possibly by altering the neurotransmitter release from the terminals innervating the nictitating membrane in the cat.

Adrenergic Fibers↗
PubMed1992

Gastrointestinal endoscope disinfection practices in India: results of a national survey.

A questionnaire was sent to 435 endoscopy centers in the country to obtain information regarding current endoscopic disinfection practices. Of these, 133 (30.6%) centers responded. Adequate disinfection (a minimum exposure to 1% glutaraldehyde for 2 minutes) before the start of endoscopy sessions and between procedures was practised in 61 (46%) and 45 (34%) centers respectively. The proportion of centers practising adequate disinfection was similar among those performing < 1500 and > 1500 endoscopies/year (50% vs 36%; p = ns). Twenty two (17%) centers used some additional precautions in patients with hepatitis B virus infection or immunocompromised states. Two (1.5%) of the 133 centers performing upper GI endoscopies and eight (18%) of the 44 centers performing ERCP examinations reported occurrence of infections following these procedures. Allergic reactions to disinfectants were reported by five (4%) centers. We conclude that only about a third of the gastroenterology centers in the country are practising adequate endoscope disinfection routinely.

Cross Infection↗
PubMed1992

Prevalence of malaria in Ao Nagas and its association with G6PD and HbE.

Glucose-6-phosphate dehydrogenase (G6PD) and hemoglobin E (HbE) were studied among 708 malarial patients and control groups of Ao Nagas from the Mokokchung District of Nagaland in the extreme northeast of India. The data suggest that malaria is an important ecologic factor in maintaining the high frequency of G6PD deficiency and HbE among the Ao Nagas. Although migrations from adjoining populations that have a high frequency of both these traits could have contributed to the presence of these genes in the Ao Nagas, malaria also could be an essential determinant in maintaining the current high frequency in present-day Ao Nagas.

Ethnicity↗
PubMed1991

Case report: unusual CT appearances in a case of Budd-Chiari syndrome.

We describe a case of Budd-Chiari Syndrome due to hepatic venous blockage in which there were multiple space-occupying lesions on CT simulating tumour deposits. Ultrasound directed liver biopsy and laparoscopy proved these to be areas of haemorrhagic necrosis consistent with Budd-Chiari Syndrome without any evidence of malignancy. The CT finding of multiple large focal non-enhancing areas in liver does not always indicate tumour deposits in a patient suspected to have Budd-Chiari Syndrome.

Adult↗
PubMed1991

Duffy blood groups and malaria in the Ao Nagas in Nagaland, India.

Blood samples from 324 malarial patients and 384 healthy individuals belonging to the Ao tribal community have been examined for Duffy blood group systems. The complete absence of Duffy-negative individuals among the Ao Nagas suggests that selection for resistance to vivax malaria by means of the Duffy-negative phenotype has not been available in the southeast Asian regions including the Ao Nagas.

Duffy Blood-Group System↗
PubMed1991

Stability of dobutamine hydrochloride in peritoneal dialysis solutions.

The stability of dobutamine hydrochloride in peritoneal dialysis solutions at 4, 26, and 37 degrees C was determined. Dobutamine (as the hydrochloride salt) was added to dialysis solutions containing 1.5% or 4.25% dextrose to concentrations of 2.5, 5.0, and 7.5 mg/mL. Samples were stored at 4, 26, and 37 degrees C to mimic refrigerator, room, and body temperature, respectively. At 0, 4, 8, and 24 hours, the samples were analyzed in triplicate by stability-indicating high-performance liquid chromatography to determine the percentage of drug remaining. More than 90% of the drug was retained under all storage conditions in 1.5% dextrose dialysate containing an initial dobutamine hydrochloride concentration of 5.0 or 7.5 micrograms/mL. The mean concentration in the samples containing an initial dobutamine hydrochloride concentration of 2.5 micrograms/mL and stored at room temperature remained greater than 90% of the initial concentration for the first four hours and then decreased to less than 90%. Dobutamine was stable in 4.25% dextrose dialysate regardless of the initial concentration or the storage condition. Dobutamine hydrochloride 5.0 and 7.5 micrograms/mL in 4.25% dextrose dialysis solution was stable under all the test conditions. Dobutamine hydrochloride 2.5 micrograms/mL was stable in 1.5% dextrose dialysate for only four hours at room temperature.

Dialysis Solutions↗
PubMed1990

Opioid and non-opioid central cardiovascular effects of ketamine.

The cardiovascular responses to ketamine injected intracisternally were examined in chloralose anaesthetized cats. Blood pressure and heart rate were recorded at different time intervals after intracisternal injection of drug or saline vehicle. The low doses of ketamine (0.5 or 1.0 mg) elicited dose dependent increase in blood pressure and heart rate. In contrast the high dose of ketamine (4 mg), produced a fall in blood pressure and heart rate. The cardiovascular response elicited by the low dose was naloxone insensitive and completely blocked by haloperidol, but not by dopamine antagonist pimozide. The vasodepressor and bradycardiac effect of the 4 mg dose was naloxone antagonizable. These data show that excitatory cardiovascular effects of the low dose result from a naloxone resistant site while in high doses an inhibitory effect is elicited by action at naloxone sensitive opiate receptors.

Animals↗
PubMed1989

Degeneration and graft-induced restoration of dopamine innervation in the weaver mouse neostriatum: a quantitative radioautographic study of [3H]dopamine uptake.

A recently introduced quantitative radioautographic technique was used to characterize the striatal dopaminergic deficit in weaver mutant mice and to evaluate the extent of DA reinnervation resulting from cell suspension grafts of fetal ventral mesencephalic tissue. Brain slices from normal mice and unilaterally grafted weaver mice were incubated in [3H]DA, in the presence of desipramine and pargyline 3-5 months after graft surgery. Semi-thin sections from the fixed and resinembedded slices were subsequently exposed on tritium sensitive film and afterwards dipped in nuclear emulsion for light microscope radioautography. Alternative slices were embedded in Epon for post-embedding tyrosine hydroxylase (TH) immunocytochemistry. The grain density of the film radioautographs matched well the distribution of TH positive fibers. Both methods revealed an almost complete absence of DA axons in the dorsomedial quadrant of the weaver neostriatum and an increasing density of DA innervation towards the ventrolateral areas. In the light microscope radioautographs, only the ventral striatum (i.e. nucleus accumbens and olfactory tubercle) and a narrow ventral and periventricular zone of the caudate-putamen were covered by silver grain clusters typical of DA varicosity labeling. Such labeled varicosities were nevertheless found in reduced numbers the lateral portion of both nucleus accumbens and the olfactory tubercle. The remaining neostriatum was overlaid by diffuse silver grains. suggesting a deficient DA uptake and storage mechanism in the residual DA fibers in this region. Immunocytochemistry using antibodies specific for DA or TH provided further evidence that the residual DA innervation in the weaver neostriatum was biochemically defective. Weaver mice with grafts of ventral mesencephalic tissue in the right neostriatum showed an amphetamine-induced rotational bias to the contralateral side, which was not seen in the sham-operated animals. In contrast to the intrinsic weaver neostriatal DA innervation, DA fibers of graft origin exhibited the normal, clustered type of varicosity labeling. The computerized image analysis of silver grain density in film radioautographs was calibrated by counting these labeled varicosities in selected areas of light microscope radioautographs from the same sections. Results showed a mean DA reinnervation of neostriatal tissue surrounding the graft of about 20%, in some cases up to 80%, of the density seen in wild type mice, with a gradual decrease with distance up to 1-1.4 mm from the graft. The ventral parts of the neostriatum, which contained higher numbers of residual intrinsic DA fibers, were much more sparsely reinnervated than the dorsal and dorsomedial areas.(ABSTRACT TRUNCATED AT 400 WORDS)

Amphetamines↗