Biomedical subjects
Publications and source records attributed to R Singh.
Impaction of the Sengstaken-Blakemore tube may occur due to incorrect placement of clamps, biting of the outlet channel(s) or inadvertent injection of particulate matter at the time of inflation of the balloon(s). Endoscopic deflation of the impacted balloon using a pointed object is an easy remedy. This report highlights the pathogenesis of this avoidable complication in one patient.
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Between April 9 and May 5 2000, an outbreak of fatal cardiotoxicity occurred in Nepal amongst visceral leishmaniasis patients treated with a recently introduced batch of generic sodium stibogluconate (SSG) from GL Pharmaceuticals, Calcutta, India. Eight (36%) of 23 patients treated with this batch died, and in 5 (23%) death was attributed to the cardiotoxicity of the drug. This contrasts with the low total death rate (3.2%) and death rate due to cardiotoxicity (0.8%) observed among 252 patients treated between August 1999 and December 2001 with generic SSG from Albert David Ltd, Calcutta, India. These data show that every batch of generic SSG should be subject to rigorous quality control prior to use.
Sodium stibogluconate (SSG) is the first-line therapy for visceral leishmaniasis (VL) in south-eastern Nepal. Recent studies from the neighbouring state of Bihar, India, have shown a dramatic fall in cure rates with treatment failure occurring in up to 65% of VL patients treated with SSG. A prospective study was conducted at a tertiary-level hospital located in south-eastern Nepal from July 1999 to January 2001. Parasitologically proven kala-azar patients with no previous history of treatment for VL were treated with SSG 20 mg/kg/d for 30 d which was extended to 40 d in those with persistent positive parasitology. Of the 110 patients who completed SSG therapy and were assessed at 1 and 6 months, definite cure was achieved in 99 patients (90%) and SSG failure occurred in 11 patients (10%). Except for the presence of hepatomegaly and a lower platelet count there was no clinical or laboratory baseline characteristic associated with treatment failure. A significantly lower cure rate (76%, P = 0.03) was observed in patients from the district of Saptari, which borders the antimony-resistant VL areas of Bihar. The efficacy of SSG as a first-line treatment for VL in south-eastern Nepal was still satisfactory, except for the patients living closer to the antimony-resistant VL areas of India. These findings indicate that the spread of resistance to antimonials is already taking place in Nepal and that a policy to control further spread should be urgently implemented.
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Thirty-one subjects who presented with plantar (metatarsal lesions only 21 out of 31 patients completed the study) completed a single blind injection of 350-centistroke polydimethicone or saline over a 6 to 9-month period. The injectable silicone conformed to European Economic Community standards and was accepted by the Medical Devices Agency (UK). The subjects were equally divided between male and female. Two randomly divided groups received silicone (n = 16) and sterile saline (n = 15). Total volumes used were not identical between the groups of subjects (p = .05), although the maximum volume was no greater than 1.5 ml in any subject. The effectiveness of the injection was reviewed using a Harris-Beath ink mat, visual analogue scale, alteration in frequency of treatment, and subjective analysis of reduction in lesions before and after by color photography. Essential histopathology was undertaken on 11 subjects. Granulomatous reactions were only positively identified in one case. Nine matched pairs showed no statistically significant difference between the two treatments (p = .082) using parametric and nonparametric tests. This study found no evidence to show that small quantities of medically prepared liquid silicone caused adverse reactions, although two cases were more sensitive after injection of silicone.
A sensitive spectrophotometric assay has been developed for maleimide groups incorporated into proteins. The assay involves the reaction of maleimide with an excess of cysteine and quantitation of the remaining cysteine using an enzymatic assay that is based on the stoichiometric conversion of an inactive disulfide form of papain to the active enzyme. The restored enzymatic activity is then measured using a chromogenic substrate. The amount of maleimide is calculated as the difference between the amounts of initial cysteine and assayed remaining cysteine. The limits of detection of this assay are about 0.1 nmol maleimide in a final assay volume of 1.2 mL. This assay is about 100-fold more sensitive than a similar assay using Ellman's reagent.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Mean values and standard deviations of height, sitting height, body weight, biacromial and bicristal diameters, total arm length, upper arm and calf girths and skinfolds at biceps, triceps, below the scapula and at the widest portion of the calf of 67 fathers, 72 mothers and their 99 adult sons and 83 adult daughters belonging to Lewa Patels of rural Gujarat are presented. Sons and daughters showed significantly higher mean values of stature as compared to fathers and mothers respectively. Parent-offspring, sib-sib and midparent-offspring correlations for these measurements are also presented. Parent-offspring and midparent-offspring correlations varied for different body measurements; highest correlations were shown by longitudinal measurements, followed by transverse diameters and least by skinfold and girth measurements. Heritability of different body measurements as indicated by midparent-offspring regression also followed a similar pattern of variation. Using the recollection method, mean age at menarche of daughters was 14.7 +/- 0.16 years and that of their mothers 15.20 +/- 0.15 years. Mother-daughter correlation for age at menarche was 0.39.
This study investigated the relationship between lipid peroxidation, subsequent activation of antioxidative enzymes, and development of iron-induced epilepsy in the rat. Epileptic foci were produced in rat cerebral cortex by intracortical injection of ferric chloride (FeCl3). The epileptic foci were identified by electrocorticography (ECoG). Epileptiform ECoG activity was shown to occur in the contralateral homotopic cerebral cortex as well. We measured levels of lipid peroxides and changes in the activities of the enzymes: superoxide dismutase (SOD), glutathione peroxidase (GP), glutathione reductase (GR), catalase (CA), and glucose-6-phosphate dehydrogenase (G6P) in the epileptogenic focus (both ipsilateral and contralateral) at days 3, 8, 15, and 23 after FeCl3 injection. Biochemical estimations were made in subcellular fractions, and changes in the ipsilateral site were compared with those in the contralateral site. The results of this study showed that large increases in lipid peroxidation were associated with development and buildup of the ECoG epileptiform discharges. Lipid peroxides increased in the ipsilateral focus by approximately 100% as compared with control. In the contralateral site, however, the increase in lipid peroxides was marginal only. The increase in lipid peroxidation was concomitant with development of the high level of epileptiform activity. The time course of changes in lipid peroxidation paralleled the time course of development and persistence of the epileptiform activity. Regarding changes in the enzyme activities accompanying development of iron epilepsy, the data showed that although SOD and G6P increased by approximately 60% and GR increased by approximately 40%, the increases in the enzyme GP and CA were much lower, less than 20%. Thus, comparatively less increase in CA and GP activities produces a deficiency of these two enzymes in the iron (ipsilateral) focus. Among the various biochemical disturbances that have been identified as involved in epileptogenesis, peroxidative injury resulting from lipid peroxidation in neural plasma membrane may be causally related to development of paroxysmal epileptiform activity in the iron focus. Since GP is an enzyme of major importance in detoxification of lipid peroxides in the brain, based on the results presented in this article, it appears reasonable to suggest that GP deficiency causes lipid peroxidation to increase tremendously during iron epileptogenesis.
Lipid peroxidation increases during ageing and has been implicated in the pathogenesis of degenerative processes associated with ageing. Despite the importance of the enzyme glutathione-S-transferase (GST) in the biotransformation and detoxification of lipid peroxidation products, there have been extremely limited studies of GST in the ageing brain. The drug chlorpromazine is known to have an activating influence on the activities of certain antioxidant enzymes (glutathione peroxidase, superoxide dismutase, etc.) and it also has anti-lipid peroxidative and anti-lipofuscin influences. Therefore, information about the age-related changes in brain GST and the effect of chlorpromazine on it in the ageing brain will be of further interest. We have, therefore, studied the effect of age on the activity of GST in the whole homogenate and cytosol fractions from the cerebral hemispheres of rats aged 1, 2, 3, 6, 12, 18 and 24 months. The effect of chlorpromazine treatment (10 mg/kg i.p. on alternate days for 6 months) was examined in the whole homogenate and cytosol fraction from the cerebral hemispheres of 6-, 12-, 18- and 24-month-old rats. The results showed that the values for GST specific activities in the cytosol fraction from all the age groups were higher then those in the whole homogenate; and the pattern of age changes in the whole homogenate differed from that in the cytosol. In the cytosol fraction the enzyme activity showed several phases of alterations: a progressive increase at 3 months of age, followed by a steady level up to 12 months of age; this phase was followed by a fall in the activity (at 18 months of age) then turned to a gradual increase. In the whole homogenate there were two phases of alterations: a progressive increase up to 12 months of age, which then turned to a somewhat gradual decrease with ageing. Thus, the decline in GST activity during ageing was evident in both the whole homogenate and cytosol. The results from chlorpromazine experiments showed that the drug elevated the GST activity in 12-, 18-, and 24-month-old animals but not in the 6-month-old animals. The drug's effects were most profound in 12-month-old animals. In conclusion, this study demonstrated an impairment of brain GST activity during ageing and the results further showed that the drug chlorpromazine attenuated the age-related impairment in the enzyme activity. The enhancement of the GST status of the ageing brain following chlorpromazine treatment is indicative of an additional antioxidative property of this drug.
OBJECTIVE: To study the relationship between granulomas in the breast and tuberculous mastitis. STUDY DESIGN: Retrospective analysis of 22 breast aspirates that showed epithelioid cell granulomas. The aspirates were reviewed and the cytomorphologic findings summarized. RESULTS: Aspiration cytology revealed epithelioid cell granulomas along with giant cells, necrosis and inflammatory cell infiltrate. Overall acid-fast bacillus (AFB) positivity was 22.7%. AFB positivity was greater in the presence of necrosis when epithelioid cells were absent. CONCLUSION: In a country like India, the diagnosis of granulomatous mastitis must be made with caution, even in the absence of AFB. Only after a sufficient trial of antituberculosis treatment has been given and the patient fails to respond should an alternative diagnosis be suggested.
OBJECTIVE: To review the cytomorphologic features of adrenocortical carcinoma (ACC), correlate them with histology and compare them with the cytomorphologic features of very similar renal cell carcinoma (RCC) on fine needle aspiration (FNA) smears. STUDY DESIGN: Cytomorphologic features in 7 cases of ACC in FNA smears were analyzed and compared with those in 10 cases of RCC. Five cases of ACC and five of RCC were later confirmed on histopathology. Parameters analyzed pertained mainly to architectural, cytoplasmic and nuclear features. RESULTS: The presence of cells in sheets with a central, thin-walled vascular core (endocrine vascular pattern); monomorphic cell population; eccentric nuclei; focal dramatic anisonucleosis; and focal spindling with crushing was a prominent feature of ACC in contrast to RCC, which showed mainly an acinar pattern with only a focal endocrine pattern, well-defined cytoplasmic angles and projections, and cytoplasmic vacuolations; pleomorphism, if present, was gradual and seen uniformly in all the cells. Univariate analysis using the chi 2 test showed the presence of endocrine architecture; focal dramatic anisonucleosis; crushed spindle fragments; eccentric nuclei; and absence of cytoplasmic vacuolizations as significant differentiating features in favor of ACC (P < .05). CONCLUSION: A cytomorphologic comparison of ACC with RCC showed that differentiation is possible by a set of statistically significant features that not only have diagnostic value but, as with crushed spindle fragments, also have prognostic significance.
In the last quarter of a century silicon-based integrated circuits (ICs) have played a major role in the growth of the economy throughout the world. A number of new technologies, such as quantum computing, molecular computing, DNA molecules for computing, etc., are currently being explored to create a product to replace semiconductor transistor technology. We have examined all of the currently explored options and found that none of these options are suitable as silicon IC's replacements. In this paper we provide fundamental device criteria that must be satisfied for the successful operation of a manufacturable, not yet invented, device. The two fundamental limits are the removal of heat and reliability. The switching speed of any practical man-made computing device will be in the range of 10(-15) to 10(-3) s. Heisenberg's uncertainty principle and the computer architecture set the heat generation limit. The thermal conductivity of the materials used in the fabrication of a nanodimensional device sets the heat removal limit. In current electronic products, redundancy plays a significant part in improving the reliability of parts with macroscopic defects. In the future, microscopic and even nanoscopic defects will play a critical role in the reliability of disruptive nanoelectronics. The lattice vibrations will set the intrinsic reliability of future computing systems. The two critical limits discussed in this paper provide criteria for the selection of materials used in the fabrication of future devices. Our work shows that diamond contains the clue to providing computing devices that will surpass the performance of silicon-based nanoelectronics.