Search PubMed⌕ Search

Biomedical subjects

S Das

Publications and source records attributed to S Das.

At least 163 records · Page 9Linked to original sources
PubMed2001

Hand-assisted laparoscopic approach to multiple-organ removal.

BACKGROUND: Over the past decade, laparoscopy has matured to a common, and in some cases, standard surgical approach. Over this time period, many technological advances have contributed to this progression, one of which is hand assistance. Hand-assisted laparoscopy allows a shortened technical learning curve, security and ease in dissection, the ability to remove organs en bloc, and shorter operative times while maintaining the postoperative advantages of laparoscopy. PATIENTS AND METHODS: We present our experience with a hand-assisted laparoscopic approach for two patients requiring bilateral nephrectomy in preparation for renal transplantation and a third patient having concurrent right simple nephrectomy and simple cystectomy for chronic pyocystis. RESULTS: The hand-assisted approach allowed for utilization of one anesthetic, repositioning of the patient without violating the sterile field, and a short convalescent time. The average hospital stay was 5 days, including two patients who required postoperative revascularization of their clotted arteriovenous fistulas. CONCLUSION: The established indications for hand-assisted laparoscopy include removal of large surgical specimens en bloc, anticipated difficult dissection, and failure of standard laparoscopic procedure progression. We propose that removal of multiple organs should be added to this list.

Adult↗
PubMed2001

Upregulation of the maturation-inducing steroid membrane receptor in spotted seatrout ovaries by gonadotropin during oocyte maturation and its physiological significance.

Changes in ovarian maturation-inducing steroid (MIS; 17,20 beta, 21-trihydroxy-4-pregnen-3-one [20 beta-S]) membrane receptor concentrations during the reproductive cycle were investigated in spotted seatrout (Cynoscion nebulosus) captured at their spawning grounds. Ovarian receptor concentrations increased gradually during ovarian recrudescence and subsequently increased rapidly during oocyte maturation, reaching 3.5-fold the prematuration values by the beginning of ovulation. The significant elevation of receptor concentrations by the germinal vesicle migration stage of oocyte maturation was accompanied by increases in circulating levels of gonadotropin (LH, GTH II) and MIS (20 beta-S). The regulation and physiological significance of the increase in ovarian MIS membrane receptor concentrations were investigated in a double in vitro incubation system. Incubation of fully grown, follicle-enclosed oocytes with hCG (10 IU/ml) for 6 h caused a two- to fourfold increase in oocyte and ovarian MIS receptor concentrations and the development of oocyte maturational competence (OMC; ability to complete oocyte maturation in vitro in response to exogenous 20 beta-S in a second incubation). Both upregulation of the MIS receptor and development of OMC in response to gonadotropin were blocked by coincubation with actinomycin D or cycloheximide, which are inhibitors of mRNA and protein synthesis, respectively, but not by cyanoketone, which is an inhibitor of 3 beta-hydroxysteroid dehydrogenase-dependent steroid synthesis. Incubation with a variety of steroids, including 20 beta-S, failed to increase receptor concentrations or to induce OMC, further supporting a steroid-independent mechanism of gonadotropin action. In contrast, insulin-like growth factor I (IGF-I) mimicked the actions of gonadotropin, which suggests IGF-I may be a component of the hormone signaling pathway. A close correlation was found between the relative increase in MIS receptor concentrations and the percentage of oocytes that became maturationally competent after treatment with different concentrations of gonadotropins and drugs that elevate cAMP levels. The finding that upregulation of the MIS receptor in response to gonadotropin and other treatments is invariably associated with the development of OMC indicates that these two processes are intimately related, and it suggests that the increase in MIS receptor concentrations is a critical regulatory step in the hormonal control of oocyte maturation.

3-Hydroxysteroid Dehydrogenases↗
PubMed2001

Jugular foramen: microscopic anatomic features and implications for neural preservation with reference to glomus tumors involving the temporal bone.

OBJECTIVE: Our goals were to study the normal histological features of the jugular foramen, compare them with the histopathological features of glomus tumors involving the temporal bone, and thus provide insight into the surgical management of these tumors with respect to cranial nerve function. METHODS: Ten jugular foramen blocks were obtained from five human cadavers after removal of the brain. Microscopic studies of these blocks were performed, with particular attention to fibrous or bony compartmentalization of the jugular foramen, the relationships of the caudal cranial nerves to the jugular bulb/jugular vein and internal carotid artery, and the fascicular structures of the nerves. In addition, we studied the histopathological features of 11 glomus tumors involving the temporal bone (10 patients), with respect to nerve invasion, associated fibrosis, and carotid artery adventitial invasion. RESULTS: A dural septum separating the IXth cranial nerve from the fascicles of Cranial Nerves X and XI, at the intracranial opening, was noted. Only two specimens, however, had a septum (one bony and one fibrous) producing internal compartmentalization of the jugular foramen. The cranial nerves remained fasciculated within the foramen, with the vagus nerve containing multiple fascicles and the glossopharyngeal and accessory nerves containing one and two fascicles, respectively. All of these nerve fascicles lay medial to the superior jugular bulb, with the IXth cranial nerve located anteriorly and the XIth cranial nerve posteriorly. All nerve fascicles had separate connective tissue sheaths. A dense connective tissue sheath was always present between the IXth cranial nerve and the internal carotid artery, at the level of the carotid canal. The inferior petrosal sinus was present between the IXth and Xth cranial nerves, as single or multiple venous channels. The glomus tumors infiltrated between the cranial nerve fascicles and inside the perineurium. They also produced reactive fibrosis. In one patient, in whom the internal carotid artery was also excised, the tumor invaded the adventitia. CONCLUSION: Within the jugular foramen, the cranial nerves lie anteromedial to the jugular bulb and maintain a multifascicular histoarchitecture (particularly the Xth cranial nerve). Glomus tumors of the temporal bone can invade the cranial nerve fascicles, and infiltration of these nerves can occur despite normal function. In these situations, total resection may not be possible without sacrifice of these nerves.

Adult↗
PubMed2001

Outbreak of Pichia anomala infection in the pediatric service of a tertiary-care center in Northern India.

An outbreak of nosocomial fungemia due to the unusual yeast, Pichia anomala occurred in the pediatric wards of our hospital over a period of 23 months (April 1996 to February 1998). A total of 379 neonates and children (4.2% admissions) were infected. The probable index case was admitted to the pediatric emergency ward, with subsequent transmission to the premature nursery, pediatric intensive care units, and other children wards. Carriage on the hands of health care personnel was likely to be responsible for dissemination of the fungus. The outbreak could only be controlled after a health education campaign to improve hand-washing practices was instituted and after nystatin-fluconazole prophylaxis to all premature neonates and high-risk infants was introduced. In a case-control study, we identified a lower gestational age, a very low birth weight (<1,500 g), and a longer duration of hospital stay as significant risk factors associated with P. anomala fungemia in premature neonates. We conducted a culture prevalence survey of 50 consecutive premature neonates and found that 28% were colonized with P. anomala at a skin or mucosal site on the date of delivery and that 20% of these neonates subsequently developed P. anomala fungemia. We performed multilocus enzyme electrophoresis on 40 P. anomala outbreak isolates (including patient and health care workers' hand isolates), and the results suggested that these isolates were identical. Our study highlights the importance of P. anomala as an emerging nosocomial fungal pathogen.

Antifungal Agents↗
PubMed2001

Pharmacokinetics of valproic acid in patients with bipolar disorder.

The pharmacokinetics of valproic acid (VPA) were studied in nine patients with bipolar disorder who were receiving VPA as prophylactic therapy, following the full daily dose (400-1500 mg), on which the patients had been maintained for at least the past 3 months. The data from our study showed that the pharmacokinetics of valproate followed a two compartment open model. A time lag of 1-2 h was observed in each patient, followed by rapid absorption, with the peak concentrations being recorded approximately 4 h after drug administration. The average 12 h trough concentration was found to be 54.73+/-11.96 microg/ml. The plasma level decline was biphasic with a terminal half-life of 14.2+/-6.39 h. Total plasma clearance was 0.095+/-0.035 ml/min/kg. The steady-state apparent volume of distribution was found to be 0.11+/-0.05 l/kg. A positive correlation (r = 0.69) was found between the dose (mg/kg) and steady-state serum concentration (Css) of VPA and all patients, except one, had their Css above 50 microg/ml. Most of the pharmacokinetic parameters in this study involving euthymic bipolar patients on long-term VPA monotherapy were found to be in agreement with those reported in literature on seizure disorder patients on similar regime; however, the plasma elimination half-life appears to be prolonged in bipolar patients.

Adult↗
PubMed2001

Fragile X syndrome in Calcutta, India.

Fragile-X-linked mental retardation usually results from amplification of the CGG repeat in the 5' untranslated region of the FMR1 gene. To assess the extent of variation of the CGG repeat in the population from the eastern region of India we studied 98 mentally retarded individuals living in and around Calcutta and identified 21 distinct alleles ranging in size from 8 to 44 CGG repeats. A repeat size of 28 was the most frequent; this value is different from the most frequent repeat size found in other studies, indicating a racial or ethnic variation. Patients with the clinical features of the syndrome have been found to carry expanded CGG repeats. Thus, it can be inferred that the expansion of CGG repeats may be a frequent cause of the syndrome in our population.

Adolescent↗
PubMed2001

Chemistry of potent anti-cancer compounds, amphidinolides.

Amphidinolides A-V represent a family of cytotoxic marine natural products with diverse structural features and pronounced biological activities. Kobayashi and his research group have been reporting over the years the discoveries of these remarkable molecules, one after another, since 1986 when the first report of the series appeared. Thanks to their perseverance and painstaking research, the family is still expanding. The unique structural features and biological activity profiles of these macrolides have obviously attracted the attention of organic chemists worldwide. The total syntheses of three members of the family, amphidinolides J, K and P, have already been achieved. This review tries to chronicle the fascinating chemistries of amphidinolides, studies on the syntheses of some of these molecules and their biological activity profiles.

Animals↗
PubMed2001

Susruta, the pioneer urologist of antiquity.

PURPOSE: Susruta, a pioneer surgeon of antiquity, practiced around 1000 BC in India. We review his many contributions with special reference to the management of urological ailments. MATERIALS AND METHODS: Information gleaned from the available English translation of 3 volumes of Susruta's treatise in surgery is analyzed with commentaries and historical perspectives chronicled by Oriental and Occidental historians. RESULTS: Susruta belonged to the period between 600 and 1000 BC. His conceptions of anatomy, physiopathology and therapeutic strategies were of unparalleled brilliance, considering the early age in the history of mankind with no supportive knowledge base preceding his era. His discussions of many aspects of urological diseases are often reaffirmed in the principles of urology today. CONCLUSIONS: Through his rational understanding, elaborate teachings and practice of the art of surgery, and many urological ailments in particular Susruta has earned the glory of being the pioneer urologist of antiquity.

Female Urogenital Diseases↗
PubMed2001

Modulation of DMBA induced genotoxicity in bone marrow by quercetin during skin carcinogenesis.

Effect of quercetin was studied on DMBA induced skin carcinogenesis in young adult Swiss albino mice. Quercetin was administered continuously with the diet (2%) for four weeks and chromosomal aberration, a predictor of future cancer risk, studied in the bone marrow cells at different time intervals. Significant reduction of chromosomal aberration was observed in bone marrow after four weeks (P< 0.02). The reduction was first evident after 96 hrs though it was not significant at this stage. Significant decrease occurred from the 21st day onward when quercetin was given in concomitance with 7,12-dimethylbenz[a]anthracene (DMBA) indicating a definite protective effect of quercetin on chromosomal aberration.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed2001

Effect of fasting on the intestinal absorption of D-glucose and D-xylose in rats in vivo.

The present study was planned to elucidate the role of fasting on the intestinal absorption of monosaccharides particularly--glucose and xylose in inbred female albino rats. Rats (weighing 250-300 grams) were divided into three groups. One group of rats served as control while the other two were experimental. One of the experimental groups was starved for 48 hours while the other for a period of 72 hours. It was found that fasting for 72 hours causes an overall increase in absorption of glucose from small intestine. Forty-eight hours of fasting caused a significant increase in glucose absorption from distal ileum only. Increase in the glucose absorption in fasting from small intestine can well be explained on the basis of a reduction in glucose metabolism in general as an adaptation to starvation so as to leave more glucose for cerebral metabolism. No significant changes, whatsoever, were encountered with xylose absorption in fasting animals.

Animals↗
PubMed2001

Effect of yogic practice on pulmonary functions in young females.

During recent years, a lot of research work has been done to show the beneficial effects of yoga training. The present study was undertaken to assess the effects of yogic practice on some pulmonary functions. Sixty healthy young female subjects (age group 17-28 yrs.) were selected. They had to do the yogic practices daily for about one hour. The observations were recorded by MEDSPIROR, in the form of FVC, FEV-1 and PEFR on day-1, after 6 weeks and 12 weeks of their yogic practice. There was significant increase in FVC, FEV-1 and PEFR at the end of 12 weeks.

Adolescent↗
PubMed2001

Fragile X syndrome a case report of a family.

Fragile X syndrome is the most common of the inherited disorders causing mental retardation. This disorder results from an abnormal expansion in (CGG)n in repeat found in the coding sequence of the FMRI gene, located at Xq 27.3. Previously it was detected by Karyotyping. With the advent of Molecular Biology PCR, has become the best method in the diagnosis of this disorder. This is a case report of a family with this disorder detected by PCR.

Adolescent↗
PubMed2000

The location and type of mutation predict malformation severity in isolated lissencephaly caused by abnormalities within the LIS1 gene.

Lissencephaly is a cortical malformation secondary to impaired neuronal migration resulting in mental retardation, epilepsy and motor impairment. It shows a severity spectrum from agyria with a severely thickened cortex to posterior band heterotopia only. The LIS1 gene on 17p13.3 encodes a 45 kDa protein named PAFAH1B1 containing seven WD40 repeats. This protein is required for optimal neuronal migration by two proposed mechanisms: as a microtubule-associated protein and as one subunit of the enzyme platelet-activating factor acetylhydrolase. Approximately 65% of patients with isolated lissencephaly sequence (ILS) show intragenic mutations or deletions of the LIS1 gene. We analyzed 29 non-deletion ILS patients carrying a mutation of LIS1 and we report 15 novel mutations. Patients with missense mutations had a milder lissencephaly grade compared with those with mutations leading to a shortened or truncated protein (P = 0.022). Early truncation/deletion mutations in the putative microtubule-binding domain resulted in a more severe lissencephaly than later truncation/deletion mutations (P < 0.001). Our results suggest that the lissencephaly severity in ILS caused by LIS1 mutations may be predicted by the type and location of the mutation. Using a spectrum of ILS patients, we confirm the importance of specific WD40 repeats and a putative microtubule-binding domain for PAFAH1B1 function. We suggest that the small number of missense mutations identified may be due to underdiagnosis of milder phenotypes and hypothesize that the greater lissencephaly severity seen in Miller-Dieker syndrome may be secondary to the loss of another cortical development gene in the deletion of 17p13.3.

1-Alkyl-2-acetylglycerophosphocholine Esterase↗