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Biomedical subjects

A Singh

Publications and source records attributed to A Singh.

At least 307 records · Page 17Linked to original sources
PubMed1997

Microorganisms and enzymes involved in the degradation of plant fiber cell walls.

One of natures most important biological processes is the degradation of lignocellulosic materials to carbon dioxide, water and humic substances. This implies possibilities to use biotechnology in the pulp and paper industry and consequently, the use of microorganisms and their enzymes to replace or supplement chemical methods is gaining interest. This chapter describes the structure of wood and the main wood components, cellulose, hemicelluloses and lignins. The enzyme and enzyme mechanisms used by fungi and bacteria to modify and degrade these components are described in detail. Techniques for how to assay for these enzyme activities are also described. The possibilities for biotechnology in the pulp and paper industry and other fiber utilizing industries based on these enzymes are discussed.

Bacteria↗
PubMed1997

Increased UV-B radiation reduces N2-fixation in tropical leguminous crops.

Net photosynthesis, leaf area, biomass, and number, size and activity of nodules were examined in three leguminous plants subjected under field conditions to supplemental UV-B radiation equivalent to a 15% ozone depletion at 25 degrees N latitude. Enhanced UV-B radiation adversely affected the net photosynthetic rate, growth characteristics and nodule activity in all three species. Maximum reduction in net photosynthesis occurred in Phaseolus mungo cv. Pant U-30, whereas the greatest reduction in nitrogenase activity occurred in Vigna radiata.

Journal Article↗
PubMed1997

Endoscopic ultrasound miniprobe-guided steroid injection for treatment of refractory esophageal strictures.

Local injection of corticosteroids into refractory esophageal strictures to decrease the restenosis rate has been reported. Here we report our efforts in three patients to render the delivery of steroids more precise, by injecting them in the thickest segment of the stricture with the guidance of a high frequency ultrasound miniprobe passed through a regular upper endoscope. Steroid injection under ultrasound miniprobe guidance may be indicated for patients who do not respond to a "blind" steroid injection without miniprobe guidance.

Aged↗
PubMed1997

Correlation of functional independence measure (FIM) and SPECT Iofetamine (I-123) as a predictor of functional return in stroke.

Function following stroke is often measured using the Functional Independence Measure (FIM). Independence occurs when the patient achieves certain levels of functions. SPECT imaging assesses the regional cerebral blood flow (rCBF). Is it possible to correlate the FIM scores with SPECT imaging and predict functional return? We evaluated total of 69 stroke patients with SPECT imaging using Iofetamine (I-123). Patients were scanned within 14-21 days post-stroke. CT scans were evaluated and correlated with the SPECT images. This information was compared with the admission and discharge FIM scores. The rCBF reperfusion changes and region of stroke were evaluated and correlated with discharge functional status. The right parietal areas demonstrated a strong correlation with SPECT and FIM changes as predictors of return of functional living status (p-value = 0.0438). The right parietal area demonstrated an improvement in ambulation (p-value = 0.0578); the right brain correlated with overall improvement in FIM scores and change in SPECT imaging (p-value = 0.0833); the left brain did not exhibit significant values. Our conclusion was that there were trends seen with the predictive value of stroke recovery using SPECT imaging. The current sample number was not large enough to provide an adequate study, especially for the left brain; a larger study is needed. This information could be useful to help determine patient placement for rehabilitation.

Activities of Daily Living↗
PubMed1997

Lymphocyte subpopulation expression in women: effect of exercise and circadian rhythm.

It is well established that exercise affects immune responses in men, but little information is available for women. Whether exercise-induced immune responses are affected by circadian rhythm has not been determined. This study examined lymphocyte responses of women to exercise in the morning (AM) and evening (PM). Lymphocytes expressing markers for T, B, and natural killer (NK) cells were identified by FACScan in blood samples collected before (baseline), immediately after, and 40 min after exercise (recovery). Absolute counts of all lymphocyte subpopulations increased immediately after exercise, but at recovery values were below baseline counts. Circadian variations were noted in absolute counts for total T, helper/inducer T cells, and B cells. Although these counts were significantly higher in the PM, the magnitude of the immune response to exercise was the same in the AM and PM. In contrast, natural killer cells, both the relative counts and the magnitude of immune response were higher in the AM. Thus, it appears that despite differences in baseline cell counts the overall exercise-induced response in most lymphocyte subpopulations is similar in the AM and PM.

Adult↗
PubMed1997

Cholecystectomy alleviates acalculous biliary pain in patients with a reduced gallbladder ejection fraction.

BACKGROUND: We sought to determine whether a reduced gallbladder ejection fraction, (GBEF) ascertained by cholecystokinin-cholescintigraphy (CCK-CS), predicts symptomatic improvement after cholecystectomy. METHODS: Medical records of patients who had had CCK-CS as well as negative results of gallbladder ultrasonography were reviewed, and patients were contacted by telephone to determine whether they had benefited from cholecystectomy. RESULTS: There were 35 patients (33 female, 2 male) who had a decreased GBEF. Cholecystectomy was done in 30, of whom 20 (67%) had resolution of pain, 8 (27%) had partial improvement, and 2 (7%) had no change. The 5 who declined cholecystectomy included none (0%) who were pain free, 2 (40%) who had partial improvement, and 3 (60%) who had no change. The clinical outcome of the two groups was significantly different. There were 14 patients (10 female, 4 male) with a normal GBEF. The 2 patients who had cholecystectomy were asymptomatic. Of the 12 patients who did not have cholecystectomy, 9 (75%) were asymptomatic, 1 (8%) had some improvement, and 2 (17%) had no change. CONCLUSIONS: Cholecystectomy is indicated for patients with acalculous biliary pain and reduced GBEF, since symptoms will likely resolve with surgery and will persist without it. Cholecystectomy for patients with a normal GBEF should be considered only after failure of a nonoperative trial, since improvement usually occurs over time.

Adolescent↗
PubMed1997

Learning-based ventricle detection from cardiac MR and CT images.

The objective of this work is to investigate the issue of automatically detecting regions of interest (ROI's) in medical images. It is assumed that the regions to be detected can be roughly segmented by a threshold based on a likelihood measure of the ROI. First, an analysis of the global histogram is used to compute a preliminary threshold that is likely near the optimal one. The histogram analysis is motivated by the analytical result of a bell image intensity model proposed in this work. Then, the preliminary threshold is used to segment the input image, resulting in an attention map, which contains an attention region that approximates the ROI as well as many spurious ones. Due to the nonoptimality of the preliminary threshold, it can happen that the attention region contains a part of, or more regions than, the ROI. Learning takes place in two stages: 1) learning for automatic selection of the preliminary threshold value and 2) learning for automatically selecting the ROI from the attention map while dynamically tuning the threshold according to the learned-likelihood function. Experiments have been conducted to approximately locate the endocardium boundaries of the left and right ventricles from gradient-echo magnetic resonance (MR) images. Cardiac computed tomography (CT) images have also been used for testing. The boundary of the segmented region provided by this algorithm is not very accurate and is meant to be used for further fine tuning based on other application-specific measures.

Algorithms↗
PubMed1997

Microorganisms as an alternative source of protein.

Demand for human food and animal feed proteins from nonconventional sources has increased, particularly in developing countries. Microbial protein is one such source. It is desirable because it is amenable to controlled intensive cultivation and is less dependent on variations in climate, weather, and soil. Microbial proteins must be evaluated for nutritive value, safety, and economic considerations before mass production is undertaken.

Animals↗
PubMed1997

Marked differences in functioning of the hypothalamic-pituitary-adrenal axis between groups of men.

To compare profiles of hypothalamic-pituitary-adrenal (HPA) responsiveness, healthy, moderately trained men (n = 15) were classified as high (n = 7) or low responders (n = 8) on the basis of plasma adrenocorticotropic hormone (ACTH) responses to strenuous treadmill exercise 4 h after 4 mg of dexamethasone (Dex). These groups were then evaluated to compare 1) HPA and growth hormone responses to exercise at 90% maximal oxygen uptake 4 h after placebo, Dex (4 mg), and hydrocortisone (100 mg); 2) pituitary-adrenal responses to infusion of arginine vasopressin (AVP); 3) plasma cortisol after a Dex suppression test (1 mg); and 4) behavioral characteristics. In comparison to low responders, high responders exhibited significantly 1) higher plasma ACTH responses to exercise after placebo and Dex; 2) higher plasma AVP secretion with exercise after placebo and marked Dex- and hydrocortisone-induced enhancement of exercise-induced AVP secretion; 3) lower Dex-induced increases in basal and stimulated growth hormone secretion; 4) higher plasma ACTH responses to infusion of AVP; and 5) a trend (P = 0.09) for higher trait anxiety ratings. Similar suppression of plasma cortisol was noted after 1 mg Dex. We conclude that subgroups of healthy male volunteers exhibit unique profiles of HPA responsiveness. We also believe that glucocorticoid pretreatment combined with strenuous exercise allows functional HPA responsiveness to be distinguished between subgroups of healthy controls and may be useful in the determination of susceptibility to disorders characterized by hyper- and hypo-HPA activation.

Adrenocorticotropic Hormone↗
PubMed1997

Hormonal and metabolic responses to exercise across time of day and menstrual cycle phase.

Two studies, each utilizing short-term treadmill exercise of a different intensity, assessed the metabolic and hormonal responses of women to exercise in the morning (AM) and late afternoon (PM). In study 1, plasma concentrations of growth hormone, arginine vasopressin, catecholamines, adrenocorticotropic hormone, cortisol, lactate, and glucose were measured before, during, and after high-intensity exercise (90% maximal O2 uptake) in the AM and PM. In study 2, plasma concentrations of adrenocorticotropic hormone, cortisol, lactate, and glucose were measured before, during, and after moderate-intensity exercise (70% maximal O2 uptake) in the AM and PM in the follicular (days 3-9), midcycle (days 10-16), and luteal (days 18-26) phases of the menstrual cycle. The results of studies 1 and 2 revealed no significant diurnal differences in the magnitude of responses for any measured variable. In addition, study 2 revealed a significant time-by-phase interaction for glucose (P = 0. 014). However, net integrated responses were similar across cycle phases. These data suggest that metabolic and hormonal responses to short-term, high-intensity exercise can be assessed with equal reliability in the AM and PM and that there are subtle differences in blood glucose responses to moderate-intensity exercise across menstrual cycle phase.

Adult↗
PubMed1997

Postoperative intravenous drip infusion is not required after minilaparotomy cholecystectomy.

OBJECTIVE: To determine if drip infusion should be discontinued after full recovery of the patient from anaesthesia after minilaparotomy cholecystectomy in uncomplicated cases. DESIGN: A randomised controlled clinical trial on 60 patients, from the waiting list, of cholelithiasis/cholecystitis operated by minilaparotomy cholecystectomy between November 1995 to March 1996. 30 patients did not receive postoperative i.v. drip infusion and in 30 patients 12-24 hours of standard drip transfusion was continued according to the current practice. SETTING: Single Surgical Unit, SS Hospital, Banaras Hindu University, Varanasi, India. MAIN OUTCOME MEASURE: Recognition of clinical indication for continuation of i.v. drip infusion after full recovery from anaesthesia. RESULTS: In the cohorts of 30 patients each who were or were not given i.v. drip infusion after full recovery from anaesthesia following minilaparotomy cholecystectomy the observations on pulse rate, blood pressure, time to first voiding of urine and time to start first oral intake of fluids were identical. However postoperative urinary retention occurred in 6 (20%) patients in whom the IV drip infusion was given. CONCLUSION: There is no clinical indication to continue IV drip infusion after full recovery from anaesthesia in patients operated for minilaparotomy cholecystectomy.

Adult↗
PubMed1997

Acute renal failure in recipients of organ transplantation and nontransplantation patients: comparison of characteristics and mortality.

Mortality from acute renal failure in critically ill patients remains in excess of 50% despite decades of improvement in supportive care. It is not known whether replacement of other failing organs by non-renal organ transplantation affects mortality in acute renal failure. We retrospectively reviewed the course of 169 patients with acute renal failure managed at a single university medical center over a 1-year period. Measures of disease severity (need for renal replacement therapy, mechanical ventilation or parenteral nutrition, presence of oliguria and APACHE II scores) and final outcome were compared in 97 patients with acute renal failure who did not receive transplants and 72 patients with acute renal failure who underwent non-renal solid organ transplants. Overall mortality was 50.3% and directly correlated with APACHE II score. Compared to nontransplant patients, transplant recipients were younger. more frequently male, and less often oliguric; but the groups were similar in mean APACHE II scores and need for renal replacement therapy, prolonged mechanical ventilation, and parenteral nutrition. Overall, mortality was significantly lower for transplant patients compared to nontransplant patients (34.7% vs. 61.9%, p < 0.05). In nonoliguric acute renal failure and renal failure not requiring renal replacement therapy, mortality was low and similar in both transplant and nontransplant patients. Compared to nontrasplant patients with similar risk factors and similar APACHE II scores, mortality was significantly lower for transplant patients who were oliguric, or who required renal replacement therapy, mechanical ventilation, or parenteral nutrition. Organ transplantation is associated with a survival advantage in acute renal failure when compared to the outcome of critically ill nontransplant patients. The relation between APACHE II scores and survival is altered by transplantation.

APACHE↗
PubMed1997

Events that stimulate release of thromboxane B2 in passive heymann nephritis.

The cause of proteinuria in passive Heymann nephritis has been attributed to the activation of the C5b-9 membrane attack complex following the antibody binding on the glomerular epithelial cell. Previous studies have shown an association between release of prostaglandin thromboxane B2 (TxB2) and proteinuria. Whether this release is dependent on antibody binding per se, or on secondary actions subsequent to antibody binding has not been clarified. The present study was designed to address this issue. Antibody binding event was experimentally separated from the proteinuria by employing a rabbit antibody which produces equivalent glomerular binding equal to that produced by a sheep antibody but without causing proteinuria. Comparisons were made with animals injected with the sheep antibody which produces all the hallmarks of the disease, including proteinuria. Animals injected with the rabbit antibody showed glomerular immunofluorescent deposits which were identical to the deposits produced by the control sheep antibody. However, rabbit antibody failed to produce the typical electron-dense subepithelial deposits, complement binding and proteinuria. Comparison of prostaglandin profile in isolated glomeruli revealed that TxB2 was unchanged in rabbit antibody-injected glomeruli (compared with its nonimmune antibody control). On the other hand, glomeruli from sheep antibody-injected animals released 45% higher TxB2 compared with their respective nonimmune antibody control. These data suggest that the binding of antibody per se may not be a sufficient stimulus for TxB2 release. Subsequent events of subepithelial electron dense deposit formation, complement activation, and proteinuria are associated with TxB2 release.

Animals↗
PubMed1997

Regulation of human sexual behaviour, sex revolution and emergence of AIDS: a historical perspective.

No Society in the World permits fully free sexual behaviour. All societies utilize a variety of ways for regulation of sexual behaviour. This has been happening since antiquity. Culture also affects sexual behaviour. In western civilization there was a healthly outlook towards sexuality during Greco-Roman era. In Indian civilization also human sexuality was considered an inseparable part of life and was given a higher place in human life. Many treatises on human sexuality were written. Sex was considered as an art and was given an exalted status through the medium of sculpture work in temples of Konark & Khajuraho. But in Christian civilization sexual acts and related areas were considered immoral, debasing, dirty and abhoring. Sex-related ideas/thoughts were considered immoral in Churches and were given low status in society. Rapidly occurring social changes in 20th century- World wars I & II, urbanization, modernization, industrialization, women emancipation and strong reaction to unprecedented suppression of 19th century suppression of sexuality led to advent of sexual revolution in America & other western countries. Liberal-sex spread throughout the society. Sexual promiscuity, prostitution, homosexuality, group-sex were socially accepted on a wide scale. Presumably as a result of these tendencies a disease like AIDS has now spread from America to the whole world. Present article is an effort of analysis of historical perspective of this problem.

Acquired Immunodeficiency Syndrome↗
PubMed1997

Treatment of elderly institutionalized bipolar patients with clozapine.

In an open trial, clozapine was used to treat 3 elderly (mean age 72 +/- 2.5 years) institutionalized male patients with bipolar I disorder, most recent episode manic, severe with psychotic features. All patients were refractory or intolerant of treatment with lithium, valproate, benzodiazepines, and traditional neuroleptics both alone and in combination. Response to clozapine was determined using the Severity of Illness score on the Clinical Global Impression (CGI) scale (1 = normal, not at all ill, 7 = among the most extremely ill). Pre-clozapine severity of illness scores on the CGI averaged 6.33 +/- 0.6; post-clozapine CGI scores averaged 2.0 +/- 1.0 (t = 13.00, df = 2, p < .01). The therapeutic dosage of clozapine varied (range = 25-112.5 mg/day). There were no significant drops in granulocyte counts. Followup revealed sustained improvement over an average of 11 months. These dramatic results suggest that clozapine may be an effective alternative treatment for similar patients and that prospective trials are warranted.

Aged↗
PubMed1997

Potential antidepressant effects of novel tropane compounds, selective for serotonin or dopamine transporters.

The forced swimming test (FST) predicts the efficacy of clinically effective antidepressants. In the present study, using the FST we examined the antidepressant potential of three novel tropane analogs: 8-methyl-2beta-propanoyl-3beta-(4-(1-methylethyl)phenyl)-8-azabicy clo[3.2.1] (WF-31) and 2beta-propanoyl-3beta-(4-(1-methylethyl)phenyl)-8-azabicyclo[3.2.1 ]octane (WF-50), selective inhibitors of serotonin uptake, and 8-methyl-2beta-propanoyl-3beta-(4-(1-methylphenyl)-8-azabicyclo[3. 2.1] octane (PTT, WF-11), a selective inhibitor of dopamine uptake. Fluoxetine and GBR 12909 were used as controls for selective inhibitors of serotonin and dopamine, respectively. Drugs were administered three times in a 24-hr period between pretest and test sessions. Intraperitoneal administration of WF-31 (0.1-10.0 mg/kg), WF-50 (0.3-10.0 mg/kg) and fluoxetine (0.3-10.0 mg/kg) dose-dependently decreased immobility while increasing swimming. In contrast, WF-11 (0.3-3.0 mg/kg) dose-dependently decreased immobility and increased both swimming and climbing, whereas GBR 12909 (3.0-30.0 mg/kg) decreased immobility, increased climbing but did not affect swimming. In a separate experiment, WF-11 (1.0 mg/kg) increased locomotor activity, whereas a higher dose of WF-11 (3.0 mg/kg) and GBR-12909 (30.0 mg/kg) produced stereotypic behaviors, suggesting that the effects in the FST may have been attributable to increases in general activity. However, the effects of WF-11 on swimming in the FST indicate that WF-11 produces antidepressant-like effects in addition to motor stimulation. These results confirm previous results that behavioral patterns manifested in the FST are characteristic of specific monoamine uptake inhibitors. In addition, these results demonstrate that WF-31 and WF-50 produce behavioral patterns similar to fluoxetine in the FST without accompanying decreases in motor activity, suggesting a potential antidepressant action. Based on comparisons with fluoxetine, the data suggest WF-31 and WF-50 may be therapeutically useful as potential antidepressant medications.

Animals↗
PubMed1997

Regulatory role of cortisone and dietary carbohydrate energy in prepubertal rat mammary gland growth and development.

Role of cortisone and regulated carbohydrate energy in mammary gland growth, based on studies of morphometric and certain growth and energy related biochemical parameters has been evaluated in the adrenalectomized prepubertal female rat. Results showed improvement or restoration of mammary features like fat pad weight, area, duct system and sprouting of end and lateral buds by cortisone treatment from adrenalectomy induced suppressed state. Similarly the hormone rectified the gland nucleic acids, glycogen and rate of tissue oxidation of glucose levels, reduced under adrenalectomy. Adrenalectomy caused loss of appetite (33.5% less than normal intake). This amount of diet restriction to normal intact did not affect the gland morphology but reduced nucleic acids, protein, glycogen and glucose oxidation rate. Provision of dextrose mixed diet to the adrenalectomized rats showed variable improvements of these biochemical parameters except the gland protein level in association with increase in appetite. However, cortisone therapy under provision of dextrose supply, restored gland protein level and increased further in nucleic acids, glycogen and glucose oxidation rate. The morphological growth parameters with dextrose and cortisone also showed further improvements. Results suggested that glucocorticoid was essential mammary growth factor during prepubertal ages. The hormone appeared to operate via tissue metabolism and stimulating energy intake through appetite stimulation.

Adrenalectomy↗