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Biomedical subjects

R Sharma

Publications and source records attributed to R Sharma.

At least 271 records · Page 15Linked to original sources
PubMed1998

Juvenile (calcifying) aponeurotic fibroma of the neck.

A case of juvenile (calcifying) aponeurotic fibroma (JAF) arising in the neck of a 5-year-old female is presented. The lesion was misdiagnosed as fibrous hamartoma of infancy (FHI) on a superficial biopsy prior to total excision of the mass. Only one instance of JAF of the neck has previously been reported; the tumor is usually located in the distal extremities and often recurs following excision. FHI occurs most frequently at and about the axilla and shoulder, and does not recur in most instances.

Calcinosis↗
PubMed1998

Aneurysm of sinus of Valsalva dissecting into interventricular septum.

BACKGROUND: Dissection of interventricular septum by aneurysm of the sinus of Valsalva is extremely rare. We present our experience with the management of 10 patients with this condition. METHODS: Ten patients with aneurysm of the sinus of Valsalva dissecting into the interventricular septum were managed at All India Institute of Medical Sciences, New Delhi, between May 1987 and September 1996. Conduction abnormalities and aortic insufficiency dominated the clinical picture. Eight patients underwent surgical repair. Two patients refused operation, and only permanent pacemaker implantation was done for complete heart block in both these patients. RESULTS: There was no hospital mortality. Follow-up ranged from 1 to 9 years. There was one late death due to carcinoma of the larynx, and 1 patient required reoperation for persistent aortic insufficiency. All other patients who underwent operation are in New York Heart Association functional class I. CONCLUSIONS: We recommend surgical repair of this condition to deal with aortic regurgitation and to avoid the potential risk of rupture, thromboembolism, and infective endocarditis. However, surgical repair offers no guarantee against arrhythmias and conduction abnormalities.

Adolescent↗
PubMed1998

Surgical experience with intracardiac myxomas: long-term follow-up.

BACKGROUND: Myxomas are the most common benign intracardiac tumors. This report summarizes our 20-year experience with these tumors. METHODS: Sixty-six patients (25 male) with a median age of 39 years (range, 6 to 70 years) underwent surgical excision of primary or recurrent intracardiac myxomas during the years 1976 to 1996. Symptom duration ranged from 2 to 8 months. There were 55 left atrial myxomas, 10 right atrial myxomas, and 1 biatrial myxoma. Three of the patients were in one family. The surgical approach comprised complete wide excision. RESULTS: There were two early deaths. Late follow-up is 89% (57/64) complete. There was one late death, which was not due to a cardiac cause. Echocardiography at a mean follow-up of 66.9 months (range, 7 to 241 months) showed no recurrence of sporadic myxomas. However, 2 of the 3 patients with familial myxomas had recurrence. CONCLUSIONS: Surgical excision of atrial myxoma gives excellent short-term and long-term results leading to eventual cure of nonfamilial myxomas. However, familial myxomas retain a strong tendency to recur even 20 years after excision.

Adolescent↗
PubMed1998

Amylases synthesis in scutellum and aleurone layer of maize seeds.

The endosperm of germinating maize seeds contains four isozymes of alpha-amylases (alpha-amylase-1 to -4) and one isozyme of beta-amylase. The alpha-amylases were purified by affinity chromatography on amylose and separated by DEAE-cellulose chromatography, into two groups, namely alpha-amylases-1,2 and alpha-amylases-3,4; and beta-amylase was purified by precipitation as a glycogen-enzyme complex. The molecular weight of alpha-amylases-1 and -2 was 46 kD, alpha-amylases-3 was 44.5 kD and of alpha-amylases-4 was 47.5 kD. The molecular weight of beta-amylase was 56 kD. During seed germination increase in amylolytic activity in endosperm was mainly contributed by secretion of alpha-amylases from adjoining aleurone layer and scutellum. The synthesis and secretion of alpha-amylases was first initiated in the scutellum followed by aleurone layers. Exogeneous Ca2+ stimulated synthesis of alpha-amylases in both eleurone layer and scutellum. In contrast, though scutellum and aleurone layer synthesized beta-amylase but it was not secreted to the medium. These results suggest that during the early germination period, alpha-amylases secreted from scutellum mobilizes starch.

Amylases↗
PubMed1998

Differential expression and properties of phenylalanine ammonia-lyase isoforms in tomato leaves.

In tomato leaves, excision and light treatments increase phenylalanine ammonia-lyase activity, which is contributed by three PAL isoforms. These isoforms possessed similar native and subunit Mr, but were different in their pI, Km for Phe and optimal pH for activity. Also these were differentially induced and affected by metabolites belonging to particular branches of phenylpropanoid pathway.

Chromatography, Gel↗
PubMed1998

Role of long-persisting human hepatitis E virus antibodies in protection.

The role of long-persisting HEV antibodies in humans was investigated. A well-characterized human volunteer anti-HEV (IgG) after 4 years of the recovery of the disease was passively immunized (200 mg kg-1 body wt) intramuscularly into three rhesus monkeys (nos 7, 8 and 9), while two monkeys (nos 5 and 6) were injected with normal immunoglobulin preparation (negative for anti-HEV IgG). At 16 h later all the animals were challenged intravenously with live HEV, as 10% stool extract prepared from the volunteer (positive for HEV by solid-phase immune electron microscopy). It was seen that transaminases (ALT/AST) were elevated in immunized monkeys on day 49 (no. 8), 60 (no. 7) and 86 (no. 9) after the virus challenge. On serological examination, all immunized (nos 7, 8 and 9) and one unimmunized (no. 6) monkeys were found positive for HEV IgM on day 10 post-challenge, while monkey no. 5 was negative. Further, all the animals from the immunized and unimmunized group seroconverted to HEV-IgG when tested on days 25 and 55 post-challenge. This has clearly shown that there is no protection. Therefore, these long-persisting HEV antibodies alone in humans, may not be protective in passive immunization.

Alanine Transaminase↗
PubMed1998

Oxidation and Reduction of Small Palladium Particles on Silica.

: We have used the technique of in situ electron microscopy to study the oxidation and reduction of the palladium (Pd) catalysts. In this study, we have subjected a Pd catalyst to oxidation and reduction cycles and studied the changes in particle structure and morphology with in situ electron diffraction and imaging. The PdO particles can be reduced to Pd metal in situ at temperatures as low as 200 degreesC in an atmosphere of a few Torr of both H2 and O2. We also found that essentially the same reduction occurred in the vacuums of 10(-6) to 10(-7) Torr in two different electron microscopes. Our in situ reduction studies show that many of the oxide particles form voids when reduced to Pd metal. The decrease in volume that occurs during reduction is often accommodated by a combination of particle shrinkage and void formation. The production of voids does not seem to depend on either the reducing atmosphere or the rate of reduction, although the voids appear to be unstable above 500 degreesC.

Journal Article↗
PubMed1998

Plasmapheresis in the treatment of steroid-resistant focal segmental glomerulosclerosis in native kidneys.

A circulating glomerular capillary albumin permeability factor (P(alb)) has been implicated in the pathogenesis of focal segmental glomerulosclerosis (FSGS), which recurs in transplanted kidneys. Plasmapheresis for recurrent FSGS may reduce proteinuria and stabilize renal function if instituted early. We performed six plasmapheresis treatments over 2 weeks in eight patients with a history of steroid-resistant idiopathic FSGS in native kidneys for an average of 12 +/- 2.3 months to determine whether treatment would decrease proteinuria or stabilize renal function. P(alb) was measured before and after plasmapheresis, and patients were followed-up for a mean of 29 +/- 4 months after the development of clinical symptoms. Proteinuria decreased in two of eight treated patients, although only transiently in one of the two. P(alb) improved in one of the two responding patients. Both patients with an improvement in proteinuria had stable renal function at last follow-up. In six of eight patients, there was no improvement in proteinuria despite an improvement in P(alb) (P < 0.0001) after plasmapheresis. At last follow-up, renal function was stable in two of the six nonresponding patients, and four of the six had significant progression of renal disease or were receiving dialysis treatments. These studies suggest that plasmapheresis may diminish proteinuria and stabilize renal function in a small minority of patients with steroid-resistant idiopathic FSGS. However, the lack of a relationship between the removal of the circulating permeability factor and the development of remission in these patients suggests that local factors associated with advanced renal injury or systemic factors unrelated to glomerular permeability play a significant role in determining proteinuria at this late stage of the disease.

Adolescent↗
PubMed1998

Bowel care for individuals with spinal cord injury: comparison of four approaches.

The efficacies of four bowel care regimens (bisacodyl suppositories, glycerin suppositories, mineral oil enemas and docusate sodium mini-enemas) were compared in seven subjects with traumatic spinal cord injury. Efficacy was assessed in terms of colonic transit time, bowel evacuation time and subjective responses to a questionnaire. Both docusate sodium mini-enemas and mineral oil enemas decreased total and left-sided colonic transit time. However, docusate sodium mini-enemas were superior to mineral oil enemas in terms of the decrease in bowel evacuation time and symptom reduction. Results in this small group of subjects suggest that docusate sodium mini-enemas may have advantages in the management of bowel evacuation in individuals with spinal cord injury.

Adult↗
PubMed1998

Alloxan diabetes regulates adenosine deaminase activity in mice: tissue- and age-specific correlation.

Effect of alloxan induced diabetes on the activity of adenosine deaminase (ADA) was studied in the liver, spleen, stomach and small intestine of mice at two different postnatal ages (preweaned, 15-day and postweaned, 60-day). Alloxan significantly stimulates (133%) ADA activity in the liver of 15-day old mice, while it has no significant effect in the 60-day old animals. In contrast, ADA activity was moderately increased (25%) in spleen of both the ages. However, no significant influence of alloxan was observed on ADA activity of stomach at either age of mice. On the other hand, alloxan treatment increases (69%) intestinal ADA activity in 15-day old mice, with no significant change in 60-day old animals. Thus, alloxan diabetes increases ADA activity in an age- and tissue-specific manner. Stimulation of ADA activity in diabetic mice might play role in immune and other metabolic dysfunctions in diabetic conditions.

Adenosine Deaminase↗
PubMed1998

Dexamethasone induced expression of phosphatase inhibits generation of reactive oxygen species in Ehrlich ascites tumor cells.

Both pre-activated and phorbol ester tetradecanoyl phorbol myristate acetate (TPA) activated reactive oxygen species (ROS) generation were inhibited by dexamethasone in vivo. Time kinetics on influence of dexamethasone on cytosolic phosphoprotein phosphatase activity revealed that, when compared to phosphatase activity in cytosol of control Ehrlich ascites tumor (EAT) cells, a 5-fold increase in specific activity is seen in the cytosol of EAT cells treated (in vivo, 0-90 min. 1 mg/kg body weight) with dexamethasone. Dexamethasone induced phosphatase was partially purified by conventional ion-exchange and gel filtration column chromatographic techniques. Purified phosphatase had a molecular weight of 70 KDa by SDS-PAGE. A dose-dependent inhibition of TPA activated ROS generation by partially purified phosphatase in permeabilized EAT cells suggested that dephosphorylation is a major regulatory mechanism in "switching off" of the respiratory burst. Anti-phosphatase antibodies were raised, purified and were used to quantitate cytosolic phosphatase by ELISA, which revealed that dexamethasone induces 6-fold increase in expression of phosphatase in EAT cells by 120 min. The expression of phosphatase in EAT cell cytosol was further confirmed by immunostaining using anti-phosphatase antibodies, the results of which showed intense blue staining on development with BCIP/NBT.

Animals↗
PubMed1998

Stimulus context in hemineglect.

Rightward deviation on bisection of a horizontal line is well described in patients with right brain injury and left hemineglect. Because of the observation that hemineglect patients may bisect very short lines to the left of the true midpoint (the so-called crossover effect), additional models have been proposed to incorporate this finding into existing theories of hemineglect. We investigated a line-length effect in six patients with left hemineglect. When presented with any set of lines of uniform (reference) length, percentage rightward deviation on line bisection remained constant across different line lengths. When lines of a second length were mixed into any uniform set of lines, bisection performance on the reference lines changed. A rightward shift in the perceived midpoint of the reference line occurred if the added lines were shorter than the reference lines; a leftward shift occurred if the added lines were longer. Leftward shifts included shifts across the true midpoint, reproducing the crossover effect. Shifts in the perceived midpoint occurred both on a manual line bisection task and on a line bisection discrimination task in which no manual response was required. We propose that the crossover effect may be part of a more general stimulus-context effect in which the perceived midpoint of a line is related not to absolute length, but to the line's length relative to other lines with which it is presented. Such a context effect has not hitherto been described in the neglect syndrome. A possible mechanism for the effect is a generalization of length estimation produced by the combined influence of the focal stimulus and all stimuli that precede it.

Adult↗
PubMed1998

Differentiation of malignant and degenerative benign bone disease using Tc-99m MDP and Tc-99m citrate scintigraphy.

The authors present a prospective analysis of Tc-99m MDP and Tc-99m citrate scintigraphy in 108 patients with known malignant or degenerative benign bone disease. Of 108 patients, 59 (group A) had malignant bone disease. The other 49 patients (group B) had degenerative benign bone disease for which the results of Tc-99m MDP scans were positive. In both groups the Tc-99m citrate scan was performed 1 week after the Tc-99m MDP scan. The Tc-99m citrate/Tc-99m MDP lesion-to-background radioisotope uptake ratio (RUR) was calculated for each lesion 3 hours after radionuclide administration. The mean RUR for the malignant lesions was 1.0 +/- 0.484; for the benign lesions, the RUR was 0.29 +/- 0.250. Static imaging was also done for 10 lesions each from the malignant and benign groups at 1, 3, and 24 hours to study the kinetics of Tc-99m citrate. Time-activity curves for malignant lesions showed that the RUR remained high for 24 hours, whereas benign lesions showed a drastic decrease at 3 and 24 hours compared with the 1-hour images. The ratio of Tc-99m citrate to Tc-99m MDP is a promising parameter to differentiate malignant from benign degenerative lesions seen as areas of increased activity on Tc-99m MDP bone scans. The sensitivity and specificity of this technique were 97.8% and 95%, respectively.

Adult↗