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P Kumar

Publications and source records attributed to P Kumar.

At least 469 records · Page 26Linked to original sources
PubMed1993

Detection of sub-nanogram quantities of Mojave toxin via enzyme immunoassay with light addressable potentiometric detector.

Sensitive detection of Mojave toxin (MoTX), a potent neurotoxin isolated from the venom of Crotalus scutulatus scutulatus, was developed using an enzyme immunoassay (EIA) and light addressable potentiometric detection. This EIA utilizes both biotin- and fluorescein-labeled anti-MoTX antibodies to immobilize and detect sub-nanogram to nanogram quantities of toxin. Labeled mono- and polyclonal anti-MoTX antibodies were used alone and/or in combination to determine maximum assay sensitivity. Assays performed using a combination of biotinylated poly- and fluoresceinated monoclonal antibodies produced an assay with a lower detection limit near 2.5 ng. Assays performed using labeled polyclonals alone, or in combination with biotinylated mono- and fluoresceinated polyclonal antibodies, indicated increased sensitivity with a detection limit near 300 pg. In conclusion, we describe an enzyme immunoassay using different labeled antibody schemes which detects sub-nanogram quantities of MoTX via light addressable potentiometric detection.

Antibodies↗
PubMed1993

Interstitial iodine 125 and concomitant cisplatin followed by hyperfractionated external beam irradiation for malignant supratentorial glioma. Preliminary experience at the University of Tennessee, Memphis.

Between November 1989 and October 1992, 28 consecutive patients with glioblastoma multiforme (n = 18) or anaplastic astrocytoma (n = 10; includes one patient with oligodendroglioma with anaplastic astrocytoma component) were treated with interstitial iodine 125 (60 Gy over 6 days) and with concomitant cisplatin (via infusion on days 2-6 of the implant), then followed by hyperfractionated external beam irradiation (110 cGy delivered twice daily; 66 Gy planned total dose). Of 26 patients (60%) who received both 125I and HEBI, 15 are alive with no evidence of recurrent disease at a median follow-up of 18 months post-125I (range: 11 to 34 months). Four other disease-free patients succumbed to nontumor-related events. Two patients with local control had distant failure outside the HEBI treatment fields. Overall local control is 77%. Local failure occurred in 6 patients (23%) 2 to 11 months post-125I. Time to disease progression ranged from 4 to 18 months (median: 10 months). Survival (measured from the date of diagnosis) has ranged from 6 to 26 months (median: 15 months). All patients have maintained Karnofsky Performance Status within 20 points of their preimplant status, with the exception of a single patient who, following diagnosis of radiation necrosis and surgical intervention for symptomatic relief, had a 30-point drop in KPS. Radiation necrosis or persistent mass effect were noted by neuroimaging in seven patients, four of whom required surgical intervention following failed medical management. Ototoxicity, nephrotoxicity, peripheral nerve dysfunction, or hematologic toxicities have not been observed. This new innovative treatment approach offers a promising alternative to the normally dismal prognosis for patients with malignant gliomas.

Adult↗
PubMed1993

Dilated heart failure in transgenic mice expressing the Epstein-Barr virus nuclear antigen-leader protein.

The Epstein-Barr virus nuclear antigen-leader protein (EBNA-LP) is required for high efficiency B lymphocyte growth transformation by the virus. To test the potential contribution of EBNA-LP to tumorigenesis in vivo, we produced transgenic mice carrying an EBNA-LP cDNA construct, using the widely expressed metallothionein promoter. Expression of EBNA-LP was detected in liver, kidney, heart, lung and spleen. There were no apparent oncogenic consequences of EBNA-LP expression. Unexpectedly however, at ages ranging from about 4 months to over a year, transgenic mice developed symptoms of congestive heart failure, including left ventricular dilatation, right ventricular hypertrophy, left atrial thrombosis, pulmonary oedema and hydrothorax. Fibrillation was not apparent in the electrocardiograph; however a reduction in T-wave amplitude suggested that the development of an abnormality of ventricular repolarization may precede the manifestation of overt symptoms. The highly predictable development of dilated heart failure in these transgenic mice suggests they may be a useful model for the pathophysiological changes associated with human dilated cardiomyopathy.

Animals↗
PubMed1993

In vivo and in vitro effects of the pineal gland and melatonin on [Ca(2+) + Mg2+]-dependent ATPase in cardiac sarcolemma.

The possible diurnal variation in cardiac [Ca(2+) + Mg2+]-dependent ATPase (Ca2+ pump) activity and the influence of pinealectomy and melatonin on this enzyme in rat heart have been studied. Lowest levels of cardiac sarcolemmal membrane [Ca(2+) + Mg2+]-dependent ATPase activity were measured in late afternoon in rats kept under a 14:10 light:dark cycle. Late in the dark phase the enzyme activity began to increase with the rise continuing until 0900, 3 hr after light onset. These time-dependent changes in [Ca(2+) + Mg2+]-dependent ATPase activity did not occur in either pinealectomized or light-exposed rats suggesting that melatonin, secreted from the pineal gland during the night, induces the change in [Ca(2+) + Mg2+]-dependent ATPase activity, In vitro studies in which cardiac tissue was incubated in the presence of melatonin over a wide range of doses showed that this indole stimulated the Ca2+ pump. The half-maximal effect of melatonin was observed at a melatonin concentration of 28 ng/ml. These findings suggest that the daily change in [Ca(2+) + Mg2+]-dependent ATPase activity in the sarcolemma of heart tissue is a result of the circadian rhythm in pineal melatonin production and secretion. These findings may be applicable to normal cardiac physiology.

Animals↗
PubMed1993

Angiogenic oligosaccharides of hyaluronan enhance the production of collagens by endothelial cells.

The present study demonstrates a relationship between angiogenic oligosaccharides of hyaluronan (HA) and the production of collagens during the process of angiogenesis in vivo and in vitro. The addition of angiogenic oligosaccharides of HA to the chorioallantoic membrane of the chick embryo induced a deposition of collagen fibrils. The treatment of sub-confluent cultures of bovine aortic endothelial cells with the same oligosaccharides (1 microgram/ml) increased the uptake of [3H]proline by approximately 60%. SDS-polyacrylamide gel electrophoresis of treated cultures demonstrated the enhanced synthesis of type I and type VIII collagens. The production of type VIII collagen was confirmed by western blotting and immunocytochemistry using antibodies to sheep and bovine type VIII collagen. Type VIII collagen is a short chain collagen that has a high degree of homology to cartilage-specific type X collagen. The biological functions of type VIII and type X collagens are unknown. We have suggested that the two collagens play a role in the process of angiogenesis.

Animals↗
PubMed1993

Some remarks on the growth-rate and angiogenesis of microvessels in ischemic stroke. Morphometric and immunocytochemical studies.

Variability in microvessel changes of blood vessel density has prompted us to undertake quantitative morphometric studies of infarcted areas in human brain. In the initial study, brains were obtained at autopsy from 10 patients (ages 45-85). Samples were collected from infarcted hemisphere and controls from the contralateral hemisphere. Formalin fixed, paraffin embedded and thereafter routinely processed sections were stained after Pickworth and with HE. Altogether 6,520 microvessels, representing 10,801 microscopic fields were counted. The Wilcoxon Range test was used for statistical analysis. In 9 of 10 patients in infarcted brain hemispheres, there was a marked increase in microvessel density (p < 0.01), when compared with contralateral brain hemisphere. In addition, a positive correlation was also found between the time of survival and both total density and density of non-perfused blood vessels. To gain a deep insight into the enhanced activity of microvessels, immunocytochemical studies were performed, which have shown, that the vascular endothelial cells in infarcted brain were reactive to two monoclonal antibodies, one, E-9, directed against an activation/proliferation associated endothelial cell specific protein and the other recognizing adhesion molecule VCAM-1. Pan-endothelial Mab PECAM/CD31 was used in those studies for controls and confirmed the obtained results. Our findings strongly support the concept of angiogenesis in the infarcted area. If correlated with morphometric results, it may indicate an important role of microvessels in pathobiology of ischemic stroke.

Aged↗
PubMed1993

A prospective clinico-bacteriological study of internal jugular cannulation in a critical care unit.

The results of 125 consecutive central venous catheterizations during a six-month period in the critical care unit were prospectively studied. All the catheters were inserted percutaneously by internal jugular approach and the placement of catheters was confirmed by chest roentgenography while injecting Conray 420. The safety of the technique was evaluated in terms of success and complication rates. Failure rate was only 0.8 per cent, while overall complication rate was 17.6 per cent. Arterial puncture and hematoma were the commonest complications encountered in 8 and 4 per cent of the patients respectively. Pneumothorax occurred in two patients (1.6%), while misplacement of catheter tip and thrombophlebitis was encountered in 0.8 per cent of all cannulations. No microorganisms were isolated from catheters inserted for less than 5 days. Positive catheter-tip cultures, by quantitative method, were obtained in 41 cases (P < 0.001) of which infected intravenous insert growing > 10(3) colony forming units, was encountered in 36 (P < 0.001) and colonization of the catheter (< 10(3) colony forming units) was seen in 5 cases. Catheter related bacteremia (recovery of the same organism from the catheter tip and peripheral blood cultures) occurred in 31 of these 41 patients (P < 0.01). The study reveals that internal jugular approach is a safe technique for central vein catheterization with very high success rate and fewer complications. However, catheter-related bacteremia is a potential threat which is directly related to the number of days the catheter is in central circulation and is totally preventable.

Adolescent↗
PubMed1993

Prolonged peritoneal dialysis in acute renal failure using Tenckhoff catheter.

The changing spectrum of acute renal failure (ARF), in children has necessitated the support by peritoneal dialysis (PD) for a longer duration. Use of permanent catheters like Tenckhoff catheter can overcome many of the problems associated with the prolonged use of temporary catheters. Thirty one infants and children with mean (SD) age of 49.3(39.4) months were subjected to PD using surgically placed Tenckhoff catheter. Catheters were put under general anesthesia in 28 patients and under local anesthesia in 3 patients. The technique of catheter insertion has been described in detail. All the catheters, except one, functioned immediately after the insertion. There was no intraperitoneal hemorrhage, dialysate leak or poor catheter drainage. The mean (SD) duration of catheter placement for PD was 11.3 (16.1) days (range 2.90 days). There were 6 episodes of infections (19.2%), peritonitis in 4 (12.8%) and exit site infection in 2 (6.4%). In 2 patients, infection episodes did not respond to antibiotics and the catheter had to be removed. There was no mortality due to complications of PD procedure and catheter insertion. Acute intermittent PD using surgically placed Tenckoff catheter was done safely for prolonged duration and also had additional advantages of good catheter drainage and no intraperitoneal hemorrhage.

Acute Kidney Injury↗
PubMed1993

Time dependent histomorphological assessment of lung damage induced by inhaled dibenz(b,f)-1-4-oxazepine (CR) and 1-chloroacetophenone (CN) in rats.

Lung damage caused by inhalation (single exposure for 60 min) of sublethal concentration of pure aerosols of dibenz(b,f)-1,4-oxazepine (CR) and 1-chloroacetophenone (CN) have been examined at different time intervals in rats. The damage was not severe with CR (2830 mg.m-3) but in the case of CN (60.26 mg.m-3) it was evident up to 30th day post exposure. Necrobiosis, attenuation of bronchiolar epithelium, edema in the air ways and also in the lumen of alveoli leading to substantial changes in the histoarchitecture of the lung were observed during CN exposure. On the other hand CR caused degenerative changes which disappeared on 30th day.

Administration, Inhalation↗
PubMed1993

Methyl xanthine and altered biomembrane dynamics: demonstration of protein mobility and enzyme inhibition by caffeine in sperm model system.

Treatment of spermatozoa with 10 mM caffeine increases the rotational mobility of thiol-containing proteins in a defined micellar micro-environment. This is associated with inhibition of superoxide dismutase activity and augmented superoxide anion radical generation. Increased sperm competence in presence of caffeine in human oligospermia is explained by these observations. Inhibition of cyclic phosphodiesterase by caffeine is suggested to be part of the observed lattice-rearrangement.

Caffeine↗
PubMed1993

Evaluation of intraoperative ultrasound in neurosurgery.

The value of real-time ultrasonography as a means of guidance during neurosurgical operations was assessed in a prospective study comprising 89 cases. There were 75 cranial and 14 spinal cases. After every such operation involving the ultrasonographic guidance, the operating surgeon subjectively assessed its usefulness vis-a-vis the information and/or help provided by it, on a scale ranging from 0 (no use) to 3 (invaluable). The intraoperative ultrasonographic guidance has been found to be extremely helpful in quickly and easily locating a small, deep-seated supratentorial lesion as also in certain spinal cases. In the absence of the much costlier CT/MRI-guidance system, intraoperative use of ultrasonography offers the desired help in majority of neurosurgical cases requiring intraoperative guidance. Additionally, it has got certain distinct advantages over the CT/MRI-guidance system.

Adolescent↗
PubMed1993

Influence of pretreatment of carbamates on dynamic pulmonary mechanics in rats exposed to sarin aerosols.

The effect of pretreatment of two carbamates, pyridostigmine and physostigmine on dynamic pulmonary mechanics has been studied in rats exposed to sarin aerosols. Sign-free dose of pyridostigmine (0.075 mg/kg, i.m.) or physostigmine (0.1 mg/kg, i.m.) did not significantly alter the parameters of the dynamic pulmonary mechanics 20 min after treatment. However, sarin (51.2 mg/m3, for 15 min) depressed the respiratory rate, air flow and minute volume and enhanced the transthoracic pressure and tidal volume. Pretreatment with carbamates 20 min prior to sarin exposure significantly modified or counteracted the above induced changes. It is concluded that the protective effect of carbamates is mainly due to the correction of respiratory changes caused by sarin aerosols in rats.

Aerosols↗
PubMed1993

Sensitivity of detection of enterotoxigenic Escherichia coli from stool sample by DNA probe.

An attempt has been made to detect the minimum counts of enterotoxigenic Escherichia coli (ETEC) in stool sample under simulated clinical condition. Thermostable (ST-la) enterotoxin-producing ETEC culture was mixed with stool sample and normal saline, centrifuged, then the supernatant was further diluted with saline and different volumes were spotted on nitrocellulose paper. Hybridization with 32P labelled pDAS-101 DNA and viable count of original culture on MacConkey agar plates with ampicillin revealed that minimum 8 cells of ETEC (ST) could be detected. The method of labelling used was sequential harnessing of the catalytic and synthetic activity of the large Klenow fragment of DNA polymerase-I. Linearizing of the DNA was dispensed with as the nicked circular DNA was excised with the gel and used for labelling directly.

Bacterial Typing Techniques↗
PubMed1993

Alcohol consumption and hypertension.

The effect of acute alcohol consumption was studied in healthy subjects (Group-I) and in nondrinking hypertensive (Group-II) and in regularly drinking hypertensive patients (Group-III). All subjects consumed alcohol (1gm/kg body weight daily) for 5 days, then abstained for 5 days. Blood pressure was recorded in standing and supine position every morning. Group-I showed no significant difference in blood pressures during and after alcohol consumption. Group-II showed a statistically significant increase in the supine and standing systolic/diastolic and mean blood pressure when consuming alcohol (P < 0.01) as compared to the period of abstinence. In Group-III, hypertensive patients who drank regularly showed significant decrease in systolic blood pressure in the period of abstinence during standing (p < 0.02) as well as in supine position (p < 0.001) and diastolic and mean blood pressure reduction in standing and supine position (p < 0.01) as compared to the period of drinking.

Adult↗
PubMed1993

Detection of Entamoeba histolytica antigens in stool in amebiasis.

BACKGROUND: Stool microscopy, the conventional method of diagnosing intestinal amebiasis, fails to detect Entamoeba histolytica in more than 30-40% of clinically suspected cases. Demonstration of parasite products in clinical specimens has been suggested as an alternative. However, the usefulness of demonstrating amebic antigen in the stools of clinical cases needs to be assessed. METHODS: A double-antibody sandwich enzyme linked immunosorbent assay (ELISA) using anti-trophozoite antibodies to capture E histolytica specific coproantigen(s) was carried out on stools obtained from 31 patients with microscopically confirmed non-dysenteric amebic colitis, 18 patients with intestinal parasites other than E histolytica and 41 apparently healthy subjects. RESULTS: The assay detected E histolytica specific coproantigen(s) in stools of 23 (74.2%) of 31 subjects with non-dysenteric amebic colitis, none of 18 with other parasitic infections and 1 (2.4%) of 41 apparently healthy subjects. CONCLUSION: Our results provide evidence for the presence of E histolytica specific coproantigen(s) in stool eluates from patients with amebic infection; this finding can be exploited for confirming ongoing amebic infection. However, the sensitivity of the assay needs to be improved by the use of relevant monospecific/monoclonal antibodies.

Animals↗
PubMed1993

End point for sclerosis of esophageal varices.

BACKGROUND: Small esophageal varices are difficult to inject intravariceally and complete eradication of varices may not be therapeutically necessary. METHODS: A prospective study designed to compare the use of different end points of sclerotherapy ie (i) total eradication (grade 0) (ii) grade I varices or (iii) grade II white (IIw) varices, by stopping variceal injection when one of these was reached. The patients were followed endoscopically and clinically at 3-4 mo intervals. OUTCOME MEASURES: Variceal recurrence and rebleeding rates. RESULTS: Of 266 patients with portal hypertension (147 cirrhosis, 51 non-cirrhotic portal fibrosis, 68 extra-hepatic portal venous obstruction), 232 (87.2%) reached one of the three end points--six to grade 0, 96 to grade I and 130 to grade IIw. Among 212 patients followed up for a mean post-sclerotherapy period of 12.2 mo (range 3-48 mo), variceal recurrence rates, time intervals to recurrence and rebleed rates were comparable in patients with endpoints of grade I and grade II (white) varices (28.5% vs 38.9%, 10.8 mo vs 9.2 mo, and 7.7% vs 7.8%, respectively; all p = ns). Overall, 51 patients had interval bleed before reaching the end point--50 (98%) of them bled from grade III and IV varices while only one patient (2%) bled with grade IIw varices. CONCLUSION: Grade I or grade IIw varices should be acceptable as the end points for endoscopic sclerotherapy of esophageal varices.

Adult↗