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Biomedical subjects

R Kapoor

Publications and source records attributed to R Kapoor.

At least 109 records · Page 6Linked to original sources
PubMed1996

Perlecan and basement membrane-chondroitin sulfate proteoglycan (bamacan) are two basement membrane chondroitin/dermatan sulfate proteoglycans in the Engelbreth-Holm-Swarm tumor matrix.

The presence of proteoglycans bearing galactosaminoglycan chains has been reported, but none has been identified previously in the matrix of the Engelbreth-Holm-Swarm tumor, which is a source of several basement membrane components. This tumor matrix contains perlecan, a large, low buoyant density heparan sulfate proteoglycan, widespread in many basement membranes and connective tissues. We now identify two distinct proteoglycan species from this tumor source, which are substituted with galactosaminoglycans and which show basement membrane localization by immunohistochemistry. One species is perlecan but, in addition to being present as a heparan sulfate proteoglycan, it is also present as a hybrid molecule, with dermatan sulfate chains. A minor population of perlecan apparently lacks heparan sulfate chains totally, and some of this is substituted with chondroitin sulfate. The second species is immunologically related to basement membrane-chondroitin sulfate proteoglycan (BM-CSPG) and bears chondroitin sulfate chains. No BM-CSPG was detectable which was substituted with heparan sulfate chains. A combination of immunological and molecular approaches, including cDNA cloning, showed that perlecan and BM-CSPG are distinct in core protein structure. Both are, however, basement membrane components, although there are tissue-specific differences in their distribution.

Animals↗
PubMed1996

Role of polymorphonuclear leukocytes in cardiovascular depression and cellular injury in hemorrhagic shock and reinfusion.

We investigated the role of polymorphonuclear leukocytes (PMNLs) in cardiac depression and cytotoxicity during hemorrhagic shock and reinfusion. The dogs were assigned to four groups: I (sham), 4 h duration; II, 2 h of shock followed by reinfusion for 2 h; III, shock and reinfusion in neutrophils depleted with immune serum; IV, same as III but pretreated with nonimmune serum. Cardiac function and contractility were depressed during shock while plasma creatine kinase (CK), and CK-MB increased. Reinfusion tended to return hemodynamic parameters towards control values while oxygen free radical producing activity of PMNLs, plasma CK, and CK-MB increased further. Cardiac malondialdehyde (lipid peroxidation product) and superoxide dismutase activity were higher while left ventricular chemiluminescence was lower in group II as compared to group I. Despite the increase in the antioxidant reserve and antioxidant enzymes, there was oxidative damage. PMNL depletion attenuated the deleterious effects of shock and reinfusion on the hemodynamic and biochemical parameters. The changes in group IV were similar to those in group II. These results suggest that PMNLs may partly be involved in the deterioration of cardiac function, and contractility and cellular injury during hemorrhagic shock and reinfusion.

Animals↗
PubMed1996

Pediatric kidney: functional outcome after extracorporeal shock wave lithotripsy.

PURPOSE: We studied the efficacy, functional outcome and morphological changes following extracorporeal shock wave lithotripsy (ESWL*) of renal calculi in a pediatric population. MATERIALS AND METHODS: We prospectively evaluated 50 patients 2 to 12 years old (mean age 7.64) undergoing ESWL with the Siemens Lithostar Plus. Functional outcome was assessed by comparing total and ipsilateral glomerular filtration rates before and after ESWL. Glomerular filtration rate was measured using Gates' method on a 99mtechnetium-pentetic acid radionuclide renal scan corrected to body surface area times 1.73 m.2. Ultrasound was performed to assess morphological changes after ESWL. RESULTS: The immediate fragmentation rate was 86% and the clearance rate was 82%. At the end of the study 40 patients were evaluable. Immediately after ESWL ultrasonography showed perirenal hematoma in 3 patients, intrarenal hematoma in 2 and subcapsular hematoma in 1. These changes resolved spontaneously at followup. There was no change in total or ipsilateral glomerular filtration rate at a mean followup of 31.7 months. Before and after ESWL total glomerular filtration rates were 86.58 +/- 12.43 and 86.27 +/- 12.82 ml. per minute per 1.73 m.2, respectively. Treated kidney glomerular filtration rate decreased insignificantly from 40.58 +/- 12.61 to 40.41 +/- 12.61 ml. per minute per 1.73 m.2 at 3 months. At the last followup the change in glomerular filtration rate was insignificant. CONCLUSIONS: ESWL is effective in the pediatric population, and it can be safely performed without long-term bio-effects on the function or morphology of the growing kidney.

Child↗
PubMed1996

Prospective randomized trial comparing endoscopic sphincterotomy followed by surgery with surgery alone in good risk patients with choledocholithiasis.

BACKGROUND: Role of endoscopic sphincterotomy (ES) in high risk patients with choledocholithiasis is established but its role in good risk patients is unclear. DESIGN: A prospective randomized trial of endoscopic sphincterotomy followed by surgery (ES + S) versus surgery alone (SA) in good risk patients with choledocholithiasis. SETTING: A tertiary level referral hospital in north India; July 1991 to October 1993. PATIENTS AND METHODS: Thirty three out of 60 patients with choledocholithiasis were found suitable for randomization--16 were randomised to ES + S group and 17 to SA group. RESULTS: Common bile duct clearance was achieved in 11/13 (85%) patients in ES + S group and in 13/15 (87%) in SA group. Major complications occurred in 4/13 (31%) patients in ES + S group and 3/16 (19%) patients in SA group. These differences were not statistically significant, but patients in ES + S group were exposed to morbidity twice, procedure related morbidity of ES being 23%. No significant differences were observed in hospital stay and cost of treatment. CONCLUSIONS: Results of this trial do not support use of precholecystectomy ES in good risk patients with choledocholithiasis, since it did not offer any advantage over surgery alone.

Adult↗
PubMed1996

Spontaneous perforation of the ureter: endourological management with renal preservation.

Spontaneous perforation of the ureter proximal to an obstruction has not been well described in the literature. We present a rare case of spontaneous perforation of the ureter, proximal to a radiolucent upper ureteric stone, in a 58-year-old diabetic female, causing a large infected urinoma and septicaemia in a solitary functioning kidney. The diagnosis was confirmed by computer tomography scan. We managed the case successfully by endourology only. The case emphasizes the importance of the differential diagnosis in a diabetic patient with obstructive uropathy.

Female↗
PubMed1996

Choledochoduodenostomy: influence of risk factors in post-operative morbidity.

BACKGROUND: Choledochoduodenostomy is performed for a variety of lower common bile duct lesions. AIMS: To analyse the influence of risk factors on the post-operative morbidity following choledochoduodenostomy. METHODS: Relation of risk factors including age more than 60 years, medical Illness, hemoglobin less than 10 g/dL, albumin less than 3 g/dL, bilirubin more than 10m/dL, presence of cholangitis at admission (treated pre-operatively), use of pre-operative endoscopic sphincterotomy and common bile duct diameter at surgery were related to the occurrence of post-operative morbidity was studied using univariate analysis. RESULTS: Fifty patients underwent choledochoduodenostomy. One patient (2%) died; major post-operative morbidity occurred in 12 patients (24%). Presence of cholangitis at admission was the only factor related (p = 0.00012) to the occurrence of post-operative morbidity. No long-term complications were encountered in 35 patients (70%) mean with followup period of 28 (range 8-60) months. CONCLUSIONS: Choledochoduodenostomy is a safe permanent drainage procedure for benign lower biliary obstruction.

Age Factors↗
PubMed1995

Functional bladder neck obstruction: a rare cause of renal failure.

We studied 7 men and 6 women (average age 33 years) who presented in renal failure with obstructive voiding symptoms or retention. Of these patients 11 had a dilated upper tract and 2 had shrunken kidneys. Mean serum creatinine at presentation was 7.0 mg./dl. No abnormality was noted on cysto-panendoscopy, retrograde urethrography and voiding cystourethrography. The patients were initially treated with clean intermittent self-catheterization following 7 to 10 days of indwelling catheterization. The majority of patients had low pressure and low flow rate at initial presentation but high end filling pressure (mean 35.3 cm. water), high voiding pressure (mean 118.9 cm. water), high opening pressure (mean 95.3 cm. water) and low peak flow (mean 5.7 ml. per second) on video pressure flow electromyography. The external sphincter was relaxed during voiding but the bladder neck opened intermittently or inadequately. No proper funneling of the bladder neck was seen. Thus, functional bladder neck obstruction was considered to be responsible for obstructive voiding in these patients. Of the patients 3 void to completion with the help of alpha blockers alone, 5 underwent bladder neck incision and are voiding well, and 5 were practicing clean intermittent self-catheterization at last followup. Serum creatinine returned to near normal in 10 patients. End stage renal failure persisted in 2 patients, 1 of whom underwent renal transplantation and is voiding well but the other died without having undergone renal replacement therapy. In the remaining patient serum creatinine was stable at 3.2 mg./dl. Mean serum creatinine at 6 months of followup was 2.33 mg.%. Bladder neck obstruction is a rare cause of renal failure which can be corrected if treated appropriately.

Adult↗
PubMed1995

A mechanism for ectopic firing in central demyelinated axons.

Intracellular recordings of ectopic activity were made from demyelinated axons in rat dorsal columns using in vitro techniques. On-going bursts of discharges were observed in some axons, and these were sometimes superimposed upon slow depolarizing potentials. These intracellularly recorded, depolarizing potentials were strongly reminiscent of the slow negative potentials previously recorded extracellularly from the periaxonal region of normal myelinated fibres following potassium loading of this space. Also, in previously silent demyelinated axons, ectopic activity could sometimes be induced by brief periods of high frequency stimulation applied remotely from the lesion. The generation of the ectopic activity can be explained in terms of an artificially increased periaxonal concentration of potassium which may lead to the opening of internodal potassium channels and an inward potassium current. We suggest that a raised periaxonal potassium concentration may occur within compartments in demyelinating lesions, and that it can result in the generation of ectopic impulses.

Action Potentials↗
PubMed1995

Beneficial effects of antioxidants in hemorrhagic shock.

The present study was undertaken to investigate the role of endogenous hydrogen peroxide (H2O2) in cardiac depression and cytotoxicity during hemorrhagic shock and reinfusion. To achieve this objective, the changes in the cardiac function and contractility, plasma creatine kinase (CK) and CK-MB activity and lactate concentration, oxyradical-producing activity of polymorphonuclear leukocytes (PMNL-CL), and cardiac malondialdehyde (MDA) concentration in anesthetized dogs were determined before and during shock and reinfusion in the presence of absence of catalase (a metabolizer of H2O2). The dogs were divided into three groups randomly. Group I: sham, four hour duration; group II: two hours of shock followed by two hours of reinfusion; group III: same as group II but pretreated with catalase. Hemorrhage shock was produced in the dogs by lowering the mean arterial pressure to 50 +/- 5 mm Hg by bleeding into standard blood bank bags containing 63 mL of citrate, phosphate, dextrose, and adenine (CPDA) anticoagulant for 450 mL of blood. The shock was maintained for two hours by bleeding or reinfusing the shed blood as needed. Cardiac function and contractility were depressed while plasma CK, CK-MB, and lactate increased during shock. Reinfusion after two hours of shock tended to return hemodynamic parameters and plasma lactate levels toward control values. Plasma CK and CK-MB and PMNL-CL increased further. Cardiac MDA content also increased after shock and reinfusion, suggesting oxidative damage. Pretreatment with catalase attenuated the deleterious effects of shock and reinfusion on the cardiovascular function and contractility, and the rise in plasma CK, CK-MB, and lactate, PMNL-CL, and cardiac MDA. However, the protection with catalase was not complete. These results suggest that hydrogen peroxide (H2O2) may partly be involved in the deterioration of cardiovascular function and cellular injury during hemorrhagic shock and reinfusion.

Analysis of Variance↗
PubMed1995

Altered topoisomerase I expression in two subclones of human CEM leukemia selected for resistance to camptothecin.

Two camptothecin-resistant variants of the CEM human leukemia cell line were developed by stepwise selection in camptothecin (CPT) in vitro. The two lines, named CEM/C1 and CEM/C2, were found to be approximately 31- and 970-fold less sensitive to CPT, respectively, than the CEM parental line and variably cross-resistant to the CPT analogs 9-amino-CPT, 10,11-methylenedioxy-CPT, and topotecan. Levels of DNA-protein complex formation resulting from cell exposure to CPT were found to be progressively reduced in the CPT-resistant cells, despite equivalent CPT accumulation in the drug-sensitive and -resistant cells. Nuclear extracts (1.0 M NaCl) prepared from the CEM/C1 and CEM/C2 lines contained 1.5- to 2-fold less DNA topoisomerase I catalytic activity per microgram of protein than did extracts from the drug-sensitive CEM line, in association with altered sensitivity of the enzyme in the CEM/C1 and CEM/C2 extracts to the inhibitory activity of CPT. Only minor differences were noted in the CPT IC50s for the topoisomerase I activity in extracts from the two CPT-resistant cell lines, however, despite the marked differences in cellular sensitivity to CPT. There were notable differences in the level of CPT-induced cleavage of DNA oligonucleotides by topoisomerase I in nuclear extracts from CEM cells compared with the drug-resistant cell extracts, with very little oligonucleotide cleavage induced by enzyme in either drug-resistant cell type, despite the use of very high (100 microM) CPT concentrations. The alterations in topoisomerase I catalytic activity were associated with reduced cellular levels of both immunoreactive topoisomerase I protein (representing 59 +/- 19% [CEM/C1] and 49 +/- 12% [CEM/C2] of that in CEM, respectively) and mRNA.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1995

A new endoscopic technique for non deflating Foley balloon.

OBJECTIVE: To describe a new technique to deflate impacted Foley balloon. METHOD: A total endourologic method using urethrotome sheath, ureteric catheter, stylet, sedoanalgesia needle and cold cup biopsy forceps is described. The technique involves minimal maneuverability of urethra. RESULTS: The technique is non traumatic, simple, and successful in almost all cases. This technique requires urology instruments which are easily available at any centre. CONCLUSION: The described technique is safe, effective non traumatic and can easily be used in cases of impacted Foley balloon. There is no damage to the posterior urethra.

Anesthesia, Local↗
PubMed1994

Purpurogallin, a scavenger of polymorphonuclear leukocyte-derived oxyradicals.

Purpurogallin (PPG) is a phenolic compound extracted from nutgalls formed on oak trees. It has been used as an additive to edible or nonedible oils or fats, and to hydrocarbon fuels or lubricants to retard their oxidation. We investigated by luminol-dependent chemiluminescence (PMNL-CL), the ability of PPG to scavenge oxygen free radicals (OFRs) generated by zymosan-activated polympophonuclear leukocytes (PMNLs). Its OFR-scavenging ability was also investigated by the use of nitro blue tetrazolium (NBT). We also investigated by the dye-exclusion method, if PPG affects the viability of PMNLs. PPG in the concentrations of 0.005-0.4 mM was used in this study. PPG scavenged OFRs produced by zymosan-activated PMNLs in a concentration-dependent manner. Almost complete scavenging was observed at a concentration of 0.2 mM. The NBT test indicated that PPG (0.2 mM) did not completely prevent the activation of PMNLs by zymosan. Viability of PMNLs in the absence or presence of PPG (0.4 mM) were 95.77 +/- 0.56% and 96.78 +/- 0.60% respectively. The results suggest that PPG scavenges OFRs produced from activated PMNLs in a concentration-dependent manner and that the cell viability is not affected by PPG. PPG is a potent scavenger of OFRs and should be of value in the prevention and treatment of diseases in the pathophysiology of which OFRs are invovled.

Animals↗
PubMed1994

Functional obstruction of the female urethra: relevance to refractory bed wetting and recurrent urinary tract infection.

A 20-year-old woman and 3 girls were referred to our urodynamic unit because of refractory bed wetting, recurrent urinary tract infection, and/or weak stream. All patients required extremely high detrusor pressure to evacuate urine, a mean of 116 cm of water. Urethral configuration was either a ballooning or a spinning-top shape. Organic stenosis of the urethra was not detected by bougie à boule. Urodynamically, functional obstruction at the distal urethra was found to be an etiology of these symptoms. When the urethra was dilated with the Otis urethrotome, all patients were greatly benefitted both symptomatically and urodynamically without an adverse effect of urinary incontinence. We stress clinical importance of pressure flow study and fluoroscopic monitoring of the bladder and urethra when one encounters female patients with long histories of above symptoms.

Adult↗
PubMed1994

Thyrotropin-releasing hormone: inhibitory function on growth hormone through both somatostatin and growth hormone-releasing factor neurons.

Double labelling immunohistochemistry using antibodies to thyrotropin releasing hormone (TRH) and somatostatin (SS) was undertaken in the anterior hypothalamus in 6 rats. Light microscopic quantitation revealed that 94.5% of SS immunopositive perikarya in the preoptic anterior hypothalamic area (PO/AHA) and 97.5% in the paraventricular nucleus appeared to be contacted by one or more TRH immunopositive terminals. In the chronically cannulated unanaesthetised male rat, unilateral microinjections of a range of doses of TRH were made in the PO/AHA, where SS neurons are located, or in the medial basal hypothalamus, where growth hormone (GH)-releasing factor (GRF) neurons are located. Transient reductions in GH plasma levels occurred only after injections of the highest (10 nmol) dose of TRH in both sites. The function of TRH inputs to both somatostatin and GRF neurons appears to be inhibitory for GH. The physiological conditions in which these inputs function remain to be defined.

Animals↗
PubMed1994

Should upper ureteral calculi be manipulated before extracorporeal shock wave lithotripsy? A prospective controlled trial.

Whether all upper ureteral stones must be manipulated before extracorporeal shock wave lithotripsy (ESWL*) is an ongoing controversy. In a prospective trial, symptomatic patients with solitary upper ureteral calculi less than 1 year in duration were alternated between ESWL in situ and pre-ESWL stone manipulation. Pretreatment excretory urograms were assessed for stone size and degree of proximal hydroureteronephrosis, which was graded from zero (no dilatation) to 3 (severe dilatation). Stone manipulation was done with the patient under intravenous sedation and local anesthesia. A total of 4,000 shock waves was given in a single session using Siemens Lithostar Plus, and treatment was repeated on days 4, 15 and 30 if required. The patients were evaluated 3 months after onset of therapy with excretory urogram and urine culture. Seventy patients qualified for the study (group 1-35 in situ and group 2-35 stone manipulation) and were comparable in relation to age and sex, stone size and degree of hydronephrosis. There was no significant difference between the 2 groups regarding the number of sessions (group 1-1.86 +/- 1.2 and group 2-2.03 +/- 1.2) or shock wave requirement (group 1-5,705.8 +/- 3,536.9 and group 2-5,549.1 +/- 3,837.2) for stone fragmentation. The degree of proximal dilatation did not contribute significantly towards the outcome (F ratio 0.675, p = 0.57). A total of 30 patients (85.5%) in group 1 had a satisfactory outcome at 3 months, while 3 (8.5%) had significant residual calculi and 2 stones could not be fragmented. Of the manipulated stones 33 (94%) were successfully cleared, while 2 patients required auxiliary procedures. Ureteroscopy was required in 1 patient for upward migration of the stent. Morbidity in both groups was comparable. We conclude that upper ureteral stones should be treated in situ to avoid the morbidity of manipulation.

Adult↗
PubMed1994

Kynurenic acid, an endogenous glutamate antagonist, in SHR and WKY rats: possible role in central blood pressure regulation.

1. Kynurenine aminotransferase catalyzes the conversion of kynurenine to kynurenic acid, an endogenous antagonist of excitatory amino acid receptors. The kynurenic acid content and kynurenine aminotransferase activity was measured in micro-dissected regions of spontaneously hypertensive rats (SHR) and their normotensive controls (Wistar-Kyoto rats: WKY). 2. Of the brain regions examined the highest kynurenine aminotransferase activity was found in the medulla followed by the olfactory bulb and the cerebellum, with the spinal cord showing the lowest activity. 3. All samples from SHR showed greatly reduced kynurenine aminotransferase activity compared to WKY. These reductions were most pronounced in the medulla and spinal cord, approximately 45-55%, and lowest in the cerebellum and olfactory bulbs, approximately 25-30%. 4. The kynurenic acid content of the rostral and caudal medulla as well as the spinal cord was also significantly lower in SHR. 5. These results suggest that there may be a deficiency in the kynurenic acid content and kynurenine aminotransferase activity in the SHR. 6. Given the accumulating evidence of the importance of medullary glutamatergic pathways in the control of blood pressure, as well as the higher sensitivity of cardiovascular neurons of SHR to applied glutamate, it seems possible that endogenous kynurenic acid in the brain may play a role in the control of blood pressure and the pathogenesis of experimental hypertension in the SHR.

Animals↗