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Biomedical subjects

S Sen

Publications and source records attributed to S Sen.

At least 19 recordsLinked to original sources
PubMed2006

Studies on commuters' exposure to BTEX in passenger cars in Kolkata, India.

Commuters' exposure to volatile organic compounds (VOCs) especially BTEX travelling in passenger cars in Kolkata, India were quantified in Phase I (2001-2002) and Phase II (2003-2004). Monitoring was made inside and in the immediate outside of passenger cars fitted with and without catalytic converters using different types of fuels, along two congested urban routes. During Phase I of the study, the benzene content in gasoline was 5% and the mean concentration of in-vehicle benzene in cars without catalytic converter was found to be as high as 721.2 microg/m3. In Phase II when the benzene content was reduced to <3% and with modified engine type, the mean in-vehicle benzene concentration was reduced to 112.4 microg/m3. The in-vehicle concentration varied with engine type and age of the vehicle. Roadside ambient mean concentration of benzene was 214.8 microg/m3 and 30.8 microg/m3 in Phase I and Phase II respectively.

Air Pollutants↗
PubMed2006

The analgesic effect of lornoxicam when added to lidocaine for intravenous regional anaesthesia.

BACKGROUND: The aim of the study was to evaluate the effect of lornoxicam (L) on sensory and motor block onset time, tourniquet pain, and postoperative analgesia, when added to lidocaine in intravenous regional anaesthesia (IVRA). METHODS: Forty-five patients undergoing hand surgery were randomly and blindly divided into three groups as to receive either i.v. saline and IVRA with lidocaine 0.5% (Control group, n=15), i.v. saline and IVRA lidocaine 0.5% with lornoxicam (L-IVRA group, n=15), or intravenous lornoxicam and IVRA lidocaine 0.5% (L-IV group, n=15). Sensory and motor blocks onset time, and tourniquet pain was measured after tourniquet application at 5, 10, 20, and 30 min, and analgesic use were recorded during operation. After the tourniquet deflation, at 1, 30 min, and 2, 4 h, visual analogue scales score, the time to first analgesic requirement, total analgesic consumption in first 24 h, and side effects were noted. RESULTS: Sensory and motor block onset times were shorter and the recovery time prolonged in the Group L-IVRA compared with the other group (P=0.001). A decreased tourniquet pain, a prolonged time first analgesic requirement [229 (85) min vs 28 (20) and 95 (24) min, P=0.0038) and less postoperative analgesic requirements during 24 h were found in Group L-IVRA compared with the other groups (P<0.05). CONCLUSIONS: The addition of lornoxicam to lidocaine for intravenous regional anaesthesia shortens the onset of sensory and motor block, decreases tourniquet pain and improves postoperative analgesia without causing any side effect.

Adult↗
PubMed2006

Observation of a pressure-induced first-order polyamorphic transition in a chalcogenide glass at ambient temperature.

An apparently first-order polyamorphic transition has been observed with increasing pressure at ambient temperature in a molecular glass of composition Ge(2.5)As(51.25)S(46.25) Raman spectroscopic measurements on pressure-quenched samples and in situ x-ray diffraction measurements indicate that this transition corresponds to a collapse of the ambient-pressure molecular phase to a high-pressure network phase. The high-pressure phase first appears at a pressure of approximately 8-9 GPa and the transformation becomes complete at approximately 14-15 GPa. Calorimetric measurements indicate that the low- and high-pressure phases are thermodynamically distinct and that they coexist in the transition range.

Journal Article↗
PubMed2006

Y-duplication of the male urethra: use of anterior anorectal wall for posterior urethral lengthening.

We have approached two patients with Y-duplication of the male urethra by a new two-staged technique to provide better results. A strip of anterior anorectal wall in continuity with the posterior urethra was used for posterior urethral lengthening and a tubed pedicled prepucial flap was used to reconstruct the anterior urethra without using the native urethra. This was done under a covering colostomy. After a gap of 6 months to allow for healing of the anorectum and to ensure adequate functioning of the perineal neourethra, second stage reconstruction was done using buried scrotal tube for the mid urethra along with colostomy closure. On follow-up at 8 and 12 months, respectively, both children were well with no stricture or fistula. There was normal anal continence and no stenosis. This technique tackles the problem in Y-duplication of the male urethra of lengthening the posterior urethral channel, which is often difficult to bring to the anterior half of the perineum especially if the opening is high up in the anorectum (case 2).

Child↗
PubMed2005

The persisting analgesic effect of low-dose intravenous ketamine after spinal anaesthesia for caesarean section.

BACKGROUND AND OBJECTIVES: To compare the analgesic effects of intrathecal fentanyl and low-dose intravenous ketamine as adjuvants to intrathecal bupivacaine for Caesarean section. METHODS: Ninety elective Caesarean section patients were randomized into three groups. Spinal anaesthesia was performed with 15 mg hyperbaric bupivacaine in all groups. Ketamine (0.15 mg kg(-1)) or an equal volume of normal saline was given intravenously immediately after initiating spinal anaesthesia in the ketamine and control group, respectively. In the fentanyl group, 10 microg fentanyl was added to the intrathecal bupivacaine. Arterial pressures, heart rate values, adverse effects, the time of first request for postoperative analgesia, visual analogue pain scores, total analgesic consumptions at 24 and 48 h were recorded in all patients. RESULTS: The time to first request for analgesia was significantly longer in the ketamine (197 min) and fentanyl (165 min) groups compared to the control group (144 min). Postoperative pain scores were significantly lower in the ketamine group than in both other groups. Although the analgesic requirements during first 24 h were significantly lower in the ketamine group, there was no significant difference between the groups during the following 24 h. CONCLUSION: Intravenous low-dose ketamine combined with intrathecal bupivacaine for Caesarean section provides longer postoperative analgesia and lower postoperative analgesic consumption than bupivacaine alone suggesting a pre-emptive effect.

Adjuvants, Anesthesia↗
PubMed2005

Effect of valsartan versus lisinopril on peritoneal sclerosis in rats.

BACKGROUND: Peritoneal sclerosis (PS) is one of the most serious causes of failure in long-term peritoneal dialysis. Angiotensin II is known to promote fibrosis and inflammation in various tissues. We previously showed that ACE inhibitors (ACEIs) have beneficial effects on hypertonic PD solutions (3.86% PD) induced peritoneal alterations. The aim of this study is to compare the effects of an ACEI and a receptor blocker on peritoneal alterations induced by hypertonic PD solutions in rats. METHODS: Forty-three non-uremic rats were divided into four groups: group I (Sham) rats received no treatment (n=11), group II received hypertonic (3.86%, 10 ml/day) PD solution (n = 10) and groups III and IV received hypertonic PD solution (10 ml/day) plus 640 mg/L valsartan (n=11) and 100 mg/L lisinopril in drinking water (n = 11). After four weeks, a one-hour peritoneal equilibration test (PET) was performed with 3.86% PD solution. Dialysate-to-plasma urea ratio (D/P urea), glucose reabsorption (D 1 /D 0 glucose), ultrafiltration volume (UF), dialysate protein, TGFbeta 1 and VEGF levels were determined. RESULTS: Administration of valsartan or lisinopril resulted in preserved UF (8+/-0.8 and 6.7+/-0.7 vs 4.9+/-0.8 mL), D1/D0 glucose (0.69+/-0.05 and 0.62+/-0.05 vs 0.56+/-0.04) and peritoneal thickness (19.4+/-2.9 and 28.5+/-5.2 vs 53+/-3 microm), respectively. Both higher level of TGF beta 1 (206+/-40 vs 474+/-120 pg/mL, p<0.05), and VEGF in dialysate effluent (4+/-0.4 vs 7.9+/-3 pg/mL, p>0.05), was determined in the dextrose group. Both cytokines are partially inhibited by valsartan or lisinopril (p >0.05) CONCLUSION: Exposure to hypertonic glucose solution resulted in alterations in peritoneal transport manifested by a rapid dissipation of the glucose gradient and resultant impaired UF response. Administration of valsartan or lisinopril led to attenuation of these alterations. We suggest that the equal protection of the peritoneal membrane from the effects of hypertonic glucose was achieved by receptor blockers and ACE inhibitors.

Angiotensin II Type 1 Receptor Blockers↗
PubMed2005

Atorvastatin improves peritoneal sclerosis induced by hypertonic PD solution in rats.

BACKGROUND: Peritoneal sclerosis is a complication of peritoneal dialysis and results in ultrafiltration failure. It is related to chronic peritoneal injury due to dialysis solution content and recurrent peritonitis. Statins have anti-inflammatory properties which may be of value in modulating responses to injury. We evaluated the capacity of atorvastatin to modify peritoneal alterations secondary to hypertonic glucose. METHODS: Thirty-two non-uremic rats were divided into three groups: group I (Sham) rats received no treatment (n=11), group II received hypertonic (3.86%, 10 ml/day) PD solution (n=10) and group III received hypertonic PD solution (10 ml/day) plus 80 mg/L atorvastatin in drinking water (n=11). After four weeks, a one-hour peritoneal equilibration test (PET) was performed with 3.86% PD solution. Dialysate-to-plasma urea ratio (D/P urea), glucose reabsorption (D 1 /D 0 glucose), ultrafiltration volume (UF), dialysate protein, TGF-beta 1 and VEGF levels were determined. RESULTS: Administration of atorvastatin resulted in preserved UF (4.9+/-0.8 vs 7.5+/-0.6 mL, p <0.01), protein loss (2.2+/-0.2 vs 2.1+/-0.1 g/L, p >0.05), and peritoneal thickness (53+/-3 vs 26+/-4 microm, p <0.01). D 1 /D 0 glucose was significantly reduced in the dextrose group (0.70+/-0.02 vs 0.56+/-0.04, p <0.01). Both higher levels of TGF-ss 1 (206+/-40 vs 474+/-120 pg/mL, p<0.05), and VEGF in dialysate effluent (4+/-0.4 vs 7.9+/-3 pg/mL, p>0.05), was determined in the dextrose group. CONCLUSION: Exposure to hypertonic glucose solution resulted in alterations in peritoneal transport manifested by a rapid dissipation of the glucose gradient and resultant impaired UF response. Administration of atorvastatin led to prevention of these alterations. We suggest that the anti-inflammatory properties of statins are useful in providing protection of the peritoneal membrane from the effects of hypertonic glucose.

Animals↗
PubMed2004

Effect of inappropriate initial empiric antibiotic therapy on outcome of patients with community-acquired intra-abdominal infections requiring surgery.

To assess the significance of initial empiric parenteral antibiotic therapy in patients requiring surgery for community-acquired secondary peritonitis, 425 patients hospitalized between January 1999 and September 2001 in 20 clinics across Germany were followed for a total of 6,521 patient days. Perforated appendix (38%), colon (27%), or gastroduodenum (22%) were the most common sites of infection. Escherichia coli was the most common pathogen. A total of 54 (13%) patients received inappropriate initial parenteral therapy not covering all bacteria isolated, or not covering both aerobes and anaerobes in the absence of culture results. Clinical success, predefined as the infection resolving with initial or step-down therapy after primary surgery, was achieved in 322 patients (75.7%; 95% confidence interval (CI), 70.6-81.2). Patients were more likely to have clinical success if initial antibiotic therapy was appropriate (78.6%; 95% CI, 73.6-83.9) rather than inappropriate (53.4%; 95% CI, 41.1-69.3). Patients having clinical success were estimated to stay 13.9 days in hospital (95% CI, 13.1-14.7), while those who had clinical failure stayed 19.8 days (95% CI, 17.3-22.3). In conclusion, appropriateness of initial parenteral antibiotic therapy was a predictor of clinical success, which in turn was associated with length of stay.

Abdomen, Acute↗
PubMed2004

Polyvinylferrocenium modified Pt electrode for the design of amperometric choline and acetylcholine enzyme electrodes.

A simple method of enzyme immobilization was investigated, which is useful for development of enzyme electrodes based on polyvinylferrocenium perchlorate coated Pt electrode surface. Enzymes were incorporated into the polymer matrix via ion exchange process by immersing polyvinylferrocenium perchlorate coated Pt electrode in enzyme solution for several times. Choline and acetylcholine enzyme electrodes were developed by co-immobilizing choline oxidase and acetylcholinesterase in polyvinylferrocenium perchlorate matrix coated on a Pt electrode surface. The amperometric responses of the enzyme electrodes were measured at +0.70 V versus SCE, which was due to the electrooxidation of enzymatically produced H2O2. The effects of the thickness of the polymeric film, pH, temperature, substrate and enzyme concentrations on the response of the enzyme electrode were investigated. The optimum pH was found to be pH 7.4 at 25 degrees C. The steady-state current of these enzyme electrodes were reproducible within +/-5.0% of the relative error. Response time was found to be 30-50s and upper limit of the linear working portions was found to be 1.2mM choline and acetylcholine concentrations in which produced detectable currents were 1.0 x 10(-6)M substrate concentrations. The apparent Michaelis-Menten constant and the activation energy of this immobilized enzyme system were found to be 1.74 mM acetylcholine and 14.9 kJ mol(-1), respectively. The effects of interferents and stability of the enzyme electrodes were also investigated.

Acetylcholine↗
PubMed2004

Ultrasonographic evaluation of lower uterine segment thickness in patients of previous cesarean section.

OBJECTIVE: To evaluate by ultrasonography, the lower uterine segment thickness of women with a previous cesarean delivery and determine a critical thickness above which safe vaginal delivery is predictable. METHODS: A prospective observational study of 71 antenatal women with previous cesarean delivery and 50 controls was carried out. Transabdominal and transvaginal ultrasonography were used in both groups to evaluate lower uterine segment thickness. The obstetric outcome in patients with successful vaginal birth and intraoperative findings in women undergoing cesarean delivery were correlated with lower segment thickness. RESULTS: The overall vaginal birth after cesarean section (VBAC) was 46.5% and VBAC success rate was 63.5%, the incidence of dehiscence was 2.82%, and there were no uterine ruptures. There was a 96% correlation between transabdominal ultrasonography with magnification and transvaginal ultrasonography. The critical cutoff value for safe lower segment thickness, derived from the receiver operator characteristic curve, was 2.5 mm. CONCLUSION: Ultrasonographic evaluation permits better assessment of the risk of scar complication intrapartum, and could allow for safer management of delivery.

Adult↗
PubMed2004

Comparison of single-breath vital capacity rapid inhalation with sevoflurane 5% and propofol induction on QT interval and haemodynamics for laparoscopic surgery.

BACKGROUND AND OBJECTIVE: To compare two techniques to achieve induction of anaesthesia for laparoscopic surgery. A single-breath vital capacity rapid inhalation induction with sevoflurane was compared to intravenous propofol. Their effects on haemodynamics and the QT interval of the electrocardiogram were assessed. METHODS: Forty-four ASA I-II patients scheduled to undergo elective laparoscopic gynaecological surgery were divided into two groups. In the sevoflurane group (Group S, n = 22), general anaesthesia was induced with a single-breath vital capacity rapid inhalation of sevoflurane 5% with nitrous oxide (N2O) 65% in O2 and then anaesthesia was maintained with sevoflurane 1-1.5% with N2O 65% in O2. In the propofol group (Group P, n = 22), general anaesthesia was induced with propofol 2 mg kg(-1) intravenously and maintained with propofol 6 mg kg(-1) h(-1). Systolic, diastolic and mean arterial pressures, heart rate and end-tidal CO2 values were recorded before anaesthesia (basic value), during the induction period (time X), at 10 min (time Y) and at 30 min (time Z) of CO2 insufflation in all patients. QT intervals were calculated using Bazett's equation. RESULTS: Systolic, diastolic and mean arterial pressure values during the induction period (time X) were lower than the basic value in both groups (P < 0.05). In Group S, QTc intervals were significantly longer during the induction period (time X) and at the tenth min of CO2 insufflation (time Y) than Group P (P < 0.05). Five patients at time X and two patients at time Y developed ventricular dysrhythmias, which improved spontaneously in Group S. In Group P, there was no significant difference in QTc intervals and only one patient developed a ventricular dysrhythmia at time Y. CONCLUSIONS: Single-breath vital capacity rapid inhalation induction technique with sevoflurane can cause prolongation of the QT interval and dysrhythmias, compared with induction and maintenance of anaesthesia with propofol in laparoscopic surgery.

Adult↗
PubMed2004

Comparison of optometry vs digital photography screening for diabetic retinopathy in a single district.

PURPOSE: To compare (a). the clinical effectiveness and (b). cost effectiveness of the two models in screening for diabetic retinopathy. METHODS: (a). Retrospective analysis of referral diagnoses of each screening model in their first respective years of operation and an audit of screen positive patients and a sample of screen negatives referred to the hospital eye service from both screening programmes. (b). Cost effectiveness study. PARTICIPANTS: (1). A total of 1643 patients screened in the community and in digital photography clinics; (2). 109 consecutive patients referred to the Diabetic Eye Clinic through the two existing models of diabetic retinopathy screening; (3). 55 screen negative patients from the optometry model; (4). 68 screen negative patients audited from the digital photography model. RESULTS: The compliance rate was 45% for optometry (O) vs 50% for the digital imaging system (I). Background retinopathy was recorded at screening in 22% (O) vs 17% (I) (P=0.03) and maculopathy in 3.8% (O) vs 1.7% (I) (P=0.02). Hospital referral rates were 3.8% (O) vs 4.2% (I) Sensitivity (75% for optometry, 80% for digital photography) and specificity (98% for optometry and digital photography) were similar in both models. The cost of screening each patient was pound 23.99 (O) vs pound 29.29 (I). The cost effectiveness was pound 832 (O) vs pound 853(I) in the first year. CONCLUSION: The imaging system was not always able to detect early retinopathy and maculopathy; it was equally specific in identifying sight-threatening disease. Cost effectiveness was poor in both models, in their first operational year largely as a result of poor compliance rates in the newly introduced screening programme. Cost effectiveness of the imaging model should further improve with falling costs of imaging systems. Until then, it is essential to continue any existing well-coordinated optometry model.

Adult↗
PubMed2004

Obesity, leptin resistance, and the effects of insulin reduction.

Leptin resistance is a hallmark of obesity, but its etiology is unknown, and its clinical measurement is elusive. Leptin-sensitive subjects have normal resting energy expenditure (REE) at a low leptin concentration, while leptin-resistant subjects have a normal REE at a higher leptin concentration; thus, the ratio of REE:Leptin may provide a surrogate index of leptin sensitivity. We examined changes in REE and leptin in a cohort of 17 obese subjects during experimental weight loss therapy with the insulin-suppressive agent octreotide-LAR, 40 mg i.m. q28d for 6 months. Six subjects lost significant weight (>10%) and BMI (>-3 kg/m(2)) with a 34% decline in leptin and a 46% decrease in insulin area under the curve (IAUC) to oral glucose tolerance testing. These subjects maintained their pretreatment REE, and thus exhibited a rise in REE:Leptin, while the other 11 showed minimal changes in each of these parameters. For the entire cohort, the change in IAUC correlated negatively with the change in REE:Leptin. These results suggest that the REE:Leptin ratio, while derivative, may serve as a useful clinical indicator of changes in leptin sensitivity within obese subjects. They also support the possibilities that hyperinsulinemia may be a proximate cause of leptin resistance, and that reduction of insulinemia may promote weight loss by improving leptin sensitivity.

Adult↗
PubMed2004

Contractile response of femoral arteries in pigs with acute liver failure.

BACKGROUND: Acute liver failure (ALF) is characterized haemodynamically by a progressive hyperdynamic circulation. The pathophysiological mechanism is unknown, but impaired contractility of vascular smooth muscle may play an important role. The aim of this study was to evaluate the vascular response to stimulation with norepinephrine and angiotensin II in endothelium-denuded femoral artery rings. METHODS: Norwegian Landrace pigs weighing 27.1 +/- 0.5 kg (mean +/- sx (standard error of the mean)) were used. ALF was induced by performing a portacaval shunt followed by ligation of the hepatic arteries (n = 6). Sham-operated animals served as controls (n = 5). Cumulative isometric concentration contraction curves were obtained after in vitro stimulation of the femoral artery rings with either angiotensin II (10(-13) - 10(-5) mol/L) or norepinephrine (10(-13) - 10(-3) mol/L). RESULTS: Pigs suffering from ALF developed a hyperdynamic circulation with an increased cardiac index (P = 0.017) and decreased systemic vascular resistance index (P = 0.015). Studies of the hind leg revealed a decreased vascular resistance index and increased blood flow compared to sham-operated controls (P = 0.003 and P = 0.01, respectively). Angiotensin II caused a concentration-dependent contraction of the arterial segments, with no significant differences in vascular responses between the two groups. Maximum force generated did not differ (55 +/- 7 versus 56 +/- 7 mN, P = 0.95). Furthermore, there were no differences for norepinephrine in the cumulative concentration-response curves and the maximum contractile force was not significantly different (87 +/- 8 versus 93 +/- 16 mN, P = 0.55). CONCLUSIONS: This study documents for the first time that there are no signs of endothelium-independent peripheral vascular hyporesponsiveness to angiotensin II and norepinephrine in pigs with ALF.

Angiotensin II↗