Search PubMed⌕ Search

Biomedical subjects

S Jain

Publications and source records attributed to S Jain.

At least 415 records · Page 23Linked to original sources

Suthi feeding.

Explore the source record for details and available documents.

Cooking and Eating Utensils↗

Acute Budd-Chiari syndrome treated by liver transplantation in a woman homozygous for factor V Leiden.

We describe the first case of Budd-Chiari syndrome due to homozygosity for factor V Leiden resulting in resistance to activated protein C. This is now recognized as the most common procoagulant disorder, and may account for many cases of Budd-Chiari syndrome previously though to be idiopathic or due to a latent myeloproliferative disorder. A further unique feature of this case is that the patient required orthotopic liver transplantation following failure of portacaval shunting and progressive hepatic necrosis. We demonstrated that liver transplantation resulted in correction of the serum coagulation abnormality; however, it is unlikely to have cured the disorder as platelet factor V would still be of the Leiden phenotype.

Acute Disease↗

Matrix metalloproteinases are expressed during wound healing after excimer laser keratectomy.

To determine the expression of matrix metalloproteinases (MMPs) in cornea following excimer laser keratectomy, two sets of experiments were performed. In the first experiment, disciform excimer keratectomy was performed on rat corneas. The central regenerating epithelium was harvested at 3-96 h postwounding. MMP levels were assayed in the regenerated central epithelium and the stroma using zymography and immunoblot assays. In the second set of experiments, deep excimer annular keratectomy was performed on rabbit corneas to induce intrastromal epithelial migration. The effect of beta-mercaptomethyl tripeptide, a synthetic inhibitor of metalloproteinase, on the presence and extent of intrastromal epithelial migration was determined. In experiment I, MMP-2 and MMP-9 were expressed in the epithelium of excimer-ablated rat corneas 6-24 h postwounding, but not in the debridement wounds and untreated controls. Only excimer-treated stroma showed MMP-9 activity. In experiment II, intrastromal epithelial migration was delayed by topical application of beta-mercaptomethyl tripeptide, a synthetic inhibitor of MMPs (p < 0.05). After excimer wounds, MMPs are expressed in corneal epithelium and stroma during wound closure. They may play an important role in wound healing after excimer laser keratectomy.

Animals↗

Day case cataract surgery without a dedicated unit.

The aim of this study was to establish that day case cataract surgery can be performed without the establishment of a dedicated day case unit. We compare the results of 100 consecutive day case cataract cases without such facility, with similar number of cataract operations amongst in-patients. All patients had standard extracapsular cataract extraction with intra-ocular lens implantation under local anaesthesia without pre-operative sedation in the day case group and the same procedure was carried out in the in-patient group under either local or general anaesthesia according to patient preference. Patients were assessed on first post-operative day, then at 2 and 6 weeks. They were also questioned about their satisfaction with the procedure. Post-operative results were comparable in the two groups. There were few complications. Most patients were satisfied with the quality of care. It was concluded that with careful assessment and counselling, day case cataract surgery can be performed successfully without setting up a dedicated day case unit.

Adult↗

Peripheral morphine analgesia: synergy with central sites and a target of morphine tolerance.

Morphine injected s.c. in the tail is a potent analgesic in the tail-flick assay when the radiant heat source is focused directly over the injection site (ED50, 4.5 micrograms), but not if the radiant heat source is moved 1 cm proximally or distally to the injection site. Naloxone given systemically reverses this peripheral analgesia. Antisense oligodeoxynucleotides directed against exons 1 and 4 of MOR-1, a cloned mu opioid receptor, administered intrathecally (i.t.) block the local analgesic effect of morphine in the tail, indicating that the local response is mediated through mu receptors located on the terminals of sensory neurons from the dorsal root ganglia. Combinations of morphine given locally in the tail and spinally (i.t.) are synergistic. Spinal morphine also synergizes with systemic morphine in analgesia assays. Supraspinal morphine enhances systemic morphine analgesia, but less dramatically. We also examined tolerance on these analgesic systems by using a daily morphine injection paradigm which shifts the dose-response curve for systemic morphine approximately 2-fold after 5 days. In this paradigm, morphine's analgesic potency after either supraspinal or spinal administration alone does not change. However, the dose-response curve for local morphine in the tail is shifted by over 19-fold. The analgesic activity of the combination of supraspinal and systemic morphine is lowered approximately 2-fold and the combination of i.t. and systemic morphine by 12-fold. These studies confirm the presence of a peripheral mechanism for morphine analgesia mediated by mu receptors located on sensory neurons from the dorsal root ganglia, which is extremely sensitive to chronic morphine dosing.

Analgesia↗

Cosolvent solubilization and formulation of an aqueous injection of ketoprofen.

Ketoprofen (1) an analgesic, antipyretic and anti-inflammatory agent, is practically insoluble in water. An increase in the aqueous solubility of 1 was attempted by various cosolvents. The solubility increased up to 8556 times (maximum) in case of ethanol while it was 33 times (minimum) in case of glycerol. Using selected cosolvents and hydrotropes, aqueous injections of 1 were formulated.

Anti-Inflammatory Agents, Non-Steroidal↗

Vasopressor responses in autosomal dominant cerebellar ataxia.

Thirteen patients with autosomal dominant cerebellar ataxia were investigated for autonomic functions using standard tests. Patients showed no significant reduction in parasympathetic responses as measured by heart rate response to slow breathing and Valsalva manoeuvre. Measurement of blood pressure response to isometric exercise, cold exposure and 70 degrees head-up tilt showed a significant decrease in sympathetic pressor response.

Adult↗

Video--EEG monitoring in intractable attacks of uncertain etiology.

Video-EEG monitoring was done in 26 patients with paroxysmal intractable attacks of uncertain etiology to determine the nature and cause. Two broad categories were identified: Those with prominent motor activity and those with attacks of collapse/limpness. Events were recorded in 16 patients of which 11 showed no abnormality on the simultaneously recorded EEG, thus helping to confirm their diagnosis of pseudoseizures.

Adolescent↗

Should patients positive for HIV infection receive pneumococcal vaccine?

Pneumococcal vaccination effectively reduces the incidence of invasive pneumococcal disease in normal subjects. Such invasive pneumococcal disease is 100 times more common in patients with HIV infection than in healthy people, so it seems logical to target this group of patients for vaccination. Few clinics routinely vaccinate patients positive for HIV, despite Department of Health guidelines. This is because of uncertainty about the vaccine's efficacy in HIV disease. There are many reasons to suspect that the vaccine will fail to protect these patients, including the fact that antibodies alone may not be sufficient protection against all serogroups of Pneumococcus and the vaccine works in healthy people but not immunocompromised subjects. Vaccination of HIV positive patients may not be indicated, at least for the time being. The cost of vaccinating such patients in the absence of data showing efficacy may well be less than the cost of a necessarily large and lengthy trial. But the truth must be sought to end current indecision.

AIDS-Related Opportunistic Infections↗

Differential effects of chronic oral antihypertensive therapies on systemic arterial circulation and ventricular energetics in African-American patients.

BACKGROUND: A comprehensive evaluation of arterial load characteristics and left ventricular energetics in systemic hypertension has been limited by the need for invasive techniques to access instantaneous aortic pressure and flow. As a consequence of this methodological limitation, no data exist on the effects of long-term antihypertensive therapy on global arterial impedance properties and indexes of myocardial oxygen consumption (MVO2). Using recently validated noninvasive techniques, we compared in hypertensive patients the effects of chronic oral treatment with ramipril, nifedipine, and atenolol on arterial impedance and mechanical power dissipation as well as indexes of MVO2. METHODS AND RESULTS: Sixteen African-American subjects with systemic hypertension were studied with a randomized, double-blind, crossover protocol. Instantaneous central aortic pressure and flow, from which arterial load characteristics can be derived, were estimated from calibrated subclavian pulse tracings (SPTs) and continuous-wave aortic Doppler velocity in conjunction with two-dimensional (2D) echocardiographic measurements of the aortic annulus, respectively. To derive ventricular wall stress and indexes of MVO2, left ventricular short- (M-mode) and long-axis (2D echo) images were acquired simultaneously with SPTs. Data were collected at the end of a 2-week washout period (predrug control) and after 6 weeks of treatment with each agent. Although all three agents reduced diastolic blood pressure to the same extent, different effects on mean and systolic pressures and vascular impedance properties were noted. Nifedipine reduced total peripheral resistance (TPR; 1744 +/- 398 versus 1290 +/- 215 dyne-s/cm5) and increased arterial compliance (ACL; 1.234 +/- 0.253 versus 1.776 +/- 0.415 mL/mm Hg). This improvement in arterial compliance was not entirely accounted for by the reduction in distending pressure. Ramipril also decreased TPR (1740 +/- 292 versus 1437 +/- 290 dyne-s/cm5) and increased ACL (1.214 +/- 0.190 versus 1.569 +/- 0.424 mL/mm Hg), but with this agent, the change in arterial compliance was explained solely on the basis of a reduction in distending pressure. Atenolol, in contrast, did not affect either TPR or ACL. In agreement with the compliance results, nifedipine and ramipril significantly lowered the first two harmonics of the impedance spectrum, but atenolol did not. None of these agents resulted in a significant change in characteristic impedance or in the relative amplitude of the reflected pressure wave. Total vascular mechanical power and percent of oscillatory power remained unaltered with all antihypertensive treatments. Only ramipril and nifedipine reduced the integral of both meridional and circumferential systolic wall stresses, indicating that MVO2 per beat was reduced with these agents. Stress-time index, a measure of MVO2 per unit time, decreased significantly with ramipril but not with nifedipine because of an increase in heart rate noted in 10 of 16 patients (mean increase, 10 beats per minute). Thus, a reduction in MVO2 coupled with unchanged total vascular mechanical power suggests improved efficiency of ventriculoarterial coupling with ramipril and with nifedipine in the subset of patients in whom heart rate remained unchanged. In contrast, there was no evidence of a reduction in wall stress, stress integral, or stress-time index with atenolol. CONCLUSIONS: The noninvasive methodology used in this study constitutes a new tool for serial and simultaneous evaluation of arterial hemodynamics and left ventricular energetics in systemic hypertension. In this study, we demonstrate the differential effects of chronic antihypertensive therapies on systemic arterial circulation and indexes of MVO2 in African-American subjects. Consideration of drug-induced differential responses of arterial load and indexes of MVO2 with each drug may provide a more physiological approach to the treatment of systemic hypertension in indivi

Administration, Oral↗

Forced coalescence phasing: a method for ab initio determination of crystallographic phases.

A method has been developed for ab initio determination of crystallographic phases. This technique, called forced coalescence phasing (FCP), is implemented on a computer and uses an automated iterative procedure that combines real space filtering with numerically seeded Fourier transforms to solve the crystallographic phase problem. This approach is fundamentally different from that of traditional direct methods of phasing, which rely on structure invariant probabilistic phase relationships. In FCP, the process begins with an appropriate set of atoms randomly distributed throughout the unit cell. In subsequent cycles of the program, these atoms undergo continual rearrangements ultimately forming the correct molecular structure(s) consistent with the observed x-ray data. In each cycle, the molecular rearrangement is directed by an electron density (Fourier) map calculated using specially formulated numerical seed coefficients that, along with the phase angles for the map, are derived from the arrangement of atoms in the preceding cycle. The method has been tested using actual x-ray data from three organic compounds. For each data set, 100 separate phase determination trials were conducted, each trial beginning with a different set of randomly generated starting phases. Correct phase sets were successfully determined in all of the trials with most trials requiring fewer than 50 cycles of the FCP program. In addition to its effectiveness in small molecule phase determination, FCP offers unexplored potential in the application of real-space methods to ab initio phasing of proteins and other macromolecule structures.

Journal Article↗

Antioxidants reduce corneal light scattering after excimer keratectomy in rabbits.

BACKGROUND AND OBJECTIVE: Excimer laser-corneal tissue interaction liberates highly reactive free radicals. Our aim was to determine if intraoperative application of antioxidants reduces the postoperative corneal light scattering by minimizing free radical-mediated cellular injury. STUDY DESIGN/MATERIALS AND METHODS: Phototherapeutic keratectomy (PTK) was performed in 20 rabbit eyes. Following 40-microns epithelial ablation, rabbits were divided into two groups and received 1-minute intraoperative application of either 50% dimethyl sulfoxide and 1% superoxide dismutase or vehicle (balanced salt solution) only. This was followed by a 6-mm diameter 100-microns PTK. Corneal light scattering was measured for 18 weeks using scatterometry. A light scattering index (SI) ranging from 0-10 was calculated; SI = 1 represents normal scattering. Light microscopic examination was performed in selected corneas. RESULTS: The mean baseline SI was similar for both groups (P = 0.95). Corneal haze followed a pattern of gradually increasing to peak at 2-3 weeks, and regressing partially thereafter. The decrease in mean SI following antioxidant application (dimethyl sulfoxide and superoxide dismutase) as compared to control group approached significance at 3 weeks (0.1 > P > 0.05) and was highly significant at 9 weeks (P < 0.05). CONCLUSION: Intraoperative application of antioxidants decreases light scattering following excimer keratectomy in rabbit corneas. UV-induced free radicals may play a role in the pathogenesis of corneal light scattering following excimer laser keratectomy.

Animals↗

Stringent regulation of human growth hormone expression in cultured murine C2C12 myoblasts by the E. coli lac repressor.

Gene transfer techniques can be used to encode the production of a polypeptide product, such as human growth hormone (hGH), that is missing in an acquired or inherited disease state such as growth hormone deficiency. In one model system, engineered C2C12 myoblasts are injected intramuscularly into a mouse and subsequently secrete hGH into the circulation. In this regard, a gene-expression regulatory system that functions in myoblasts would be of interest. We demonstrate that the Escherichia coli ldc operon system can be used to stringently regulate the expression of hGH in engineered C2C12 myoblasts in tissue culture. A DNA segment encoding hGH was linked to a DNA segment containing an SV40 enhancer and promoter. The latter components were positioned between two synthetic lac operators. Lac repressor expression was driven by a simian cytomegalovirus promoter. In transient co-transfection assays, hGH expression from cultured C2C12 myoblasts could be modulated up to 60-fold (P = 0.002) with the inducing agent, isopropyl-beta-D-thiogalactoside (IPTG). In the absence of IPTG, hGH expression was almost fully repressed. These results show that the components of the E. coli lac operon provide a stringent regulatory system for use in myoblasts. The system might prove to be useful for the regulation of transferred genes in animals.

Animals↗