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Biomedical subjects

K Kumar

Publications and source records attributed to K Kumar.

At least 127 records · Page 7Linked to original sources
PubMed1992

A correlative study of serum zinc and in vivo cell mediated immune status in rheumatic heart disease.

This study was conducted to determine the zinc status and assess relationship between serum zinc and in vivo cell mediated immunity (CMI) in patients with rheumatic heart disease (RHD). The study comprised 22 patients with active rheumatic heart disease (ARHD), 15 patients with chronic rheumatic heart disease without activity (CRHD) (selection based on Jone's Criteria--Revised), and 15 age and sex matched healthy control. Zinc estimation was done by atomic absorption spectrophotometer. To assess CMI in vivo, phytohaemagglutinin skin test and skin window test were done. Serum zinc and in vivo CMI in patients with ARHD and CRHD compared with controls. Mean serum zinc was significantly decreased in patients with ARHD and CRHD, more pronounced in the former (P less than 0.001); and mean 24 h urinary zinc was significantly increased in patients with ARHD (P less than 0.001) as compared to controls. A significant depression in CMI in vivo was observed in patients with ARHD and CRHD (P less than 0.001). A significant positive correlation was seen among serum zinc and markers of in vivo CMI (P less than 0.001). In conclusion, depletion of zinc, observed in RHD, probably causes immune alterations and suggest role of zinc in immunopathogenesis of RHD. Zinc supplementation may alter the course of rheumatic fever and RHD.

Adolescent↗
PubMed1991

Electrophysiologic effects of oral diltiazem before and after beta blockade.

We conducted electrophysiologic (EP) studies and estimated the sinus node function and atrioventricular (AV) conduction in 10 patients with suspected coronary arterial disease (age range 35-55 years) before and during diltiazem therapy (60 mg thrice daily for 5-7 days). The effect of beta blockade (0.1 mg/kg of intravenous propranolol) was evaluated in both EP studies. The mean spontaneous sinus cycle length (SCL) and the AV nodal Wenckebach cycle lengths (AVWB) were significantly higher (p less than 0.05) after propranolol alone (913 +/- 131 and 504 +/- 197 ms, respectively) compared with baseline values (SCL: 827 +/- 149 ms, AVWB: 439 +/- 173 ms). Diltiazem alone failed to influence the SCL and AVWB significantly. Following the combination (diltiazem + propranolol), SCL (945 +/- 147 ms) and AVWB (533 +/- 148 ms) were significantly higher (p less than 0.05) than baseline and post diltiazem values (SCL: 840 +/- 150 ms; AVWB 457 +/- 103 ms). None of the other parameters (sinoatrial conduction time, corrected sinus node recovery time, AH and HV intervals, AV nodal and atrial effective refractory periods) were significantly influenced by propranolol, diltiazem, or the combination. No patient developed AV block, sinus arrest/sinoatrial exit block, or symptomatic sinus bradycardia following beta blockade after diltiazem administration. Oral diltiazem therapy alone and after beta blockade does not appear to adversely influence the sinus node function and AV conduction in patients below the age of 55 years. The combination of diltiazem and beta blocker thus appears safe in selected patients with coronary arterial disease.

Administration, Oral↗
PubMed1991

Cardiac involvement in nonspecific aortoarteritis (Takayasu's arteritis).

Fifty-four patients (18 males and 36 females, ages 2 to 37 years) with nonspecific aortoarteritis (NSAA) were studied. Evaluation revealed hypertension in 35, congestive heart failure (CHF) in 24, mild to moderate mitral regurgitation in six, and mild aortic regurgitation in two. Erythrocyte sedimentation rate was raised (greater than 35 mm in the first hour) in 38 patients. The arterial lesions included type I in seven, type II in eight, and type III in 34. Pulmonary artery involvement was present in 4 (type IV) of the 20 patients in whom it was studied. Selective coronary angiography was done in 11 patients and revealed 90% left main stenosis in one patient. Hemodynamic data revealed raised (greater than 7 mm Hg) mean right atrial pressure in nine, raised mean pulmonary artery pressure (greater than 20 mm Hg) in 29, and raised left ventricular filling pressure (greater than 12 mm Hg) in 27 patients. Radionuclide ventriculography revealed reduced (less than 45%) left ventricular ejection fraction (LVEF) in 27 patients. The myocardial morphology as evaluated on right ventricular endomyocardial biopsy revealed normal histology in nine, features of inflammatory myocarditis in 24, and nonspecific changes suggestive of dilated cardiomyopathy in six patients. Marked right ventricular endocardial thickening was present in three. All patients with CHF had some histologic abnormality. We emphasize that myocardial involvement including myocarditis is common in NSAA and may precipitate CHF in these patients.

Adolescent↗
PubMed1991

Comparison of vascular perfusion in ischemia-sensitive and ischemia-resistant regions of gerbil brain by an automated laser cytometric device: a preliminary study.

Reduced blood supply in the hippocampus has been considered to be a factor contributory to this region's selective susceptibility to ischemia. To determine if there are differences in vascularization of vulnerable and resistant regions of the brain, a quantitative morphometric assessment of vascular filling was performed in the gerbil brain by using a relatively new and highly sensitive automated laser cytometric device, ACAS (Adherent Cell Analysis and Sorting). Evan's blue, an intravital vascular tracer, was injected intracardiac in 5 Mongolian gerbils to identify perfused blood vessels in the cortex and CA1 region of hippocampus. Exactly 3 min later, the animal was decapitated, the brain removed and sections prepared for fluorescent quantitative morphometric analysis of blood vessels. The perfused vessels appeared as fluorescent structures due to the autofluorescent property of Evan's blue. Several fields in each of the two specified regions were studied and integrated numbers of blood vessels/mm2 obtained for statistical comparisons. Control brains perfused with normal saline (vehicle for Evan's blue) were used to determine the background fluorescence. The number of perfused blood vessels of all sizes was found to be lower in the CA1 sector of hippocampus than that in the cerebral cortex. The number of capillary size vessels was also lower in the CA1 region but the difference was not significant. Since it is the capillaries that are of prime importance in the diffusion system, and we found no significant regional difference in the density of capillary size vessels, it appears unlikely that the peculiarities of patterns of vascularization contribute significantly to vulnerability to ischemia.

Animals↗
PubMed1991

Probe angioplasty through an intracoronary probing catheter in lesions which are difficult to cross.

The clinical records of the first 17 consecutive patients (20 lesions) in whom percutaneous transluminal coronary angioplasty was done using the ultra-low profile "balloon-on-wire probe" passed through an intracoronary probing catheter were reviewed. All patients had high-grade "difficult" lesions. In 15 lesions (12 patients) other balloon systems (over-the-wire low profile balloons (n = 9), and balloon-on-wire used alone, (n = 6)) had failed to cross the lesion. Acute ischemia due to complete occlusion at the site of the lesion during attempts to cross was seen in 3 of these patients. The intracoronary probing catheter was used to deliver the probe across the lesion in all these cases. Successful dilatation was achieved in 14 lesions (93%). In 5 lesions (5 patients) this combination was used as the initial strategy. Three of these had chronic total occlusions. Successful dilatation was achieved in 3 lesions (60%) using this combination and in 1 lesion over-the-wire balloon finally succeeded. There was 1 failure. The intracoronary probing catheter in combination with probe balloon wire offers a promising method to increase the success rate in patients with high grade "difficult" lesions. This combination is especially useful in situations where other balloon systems fail to cross the lesion.

Angioplasty, Balloon, Coronary↗
PubMed1991

Reaction of gadolinium chelates with endogenously available ions.

The extent of reaction of 153Gd-radiolabeled Gd(L) chelates with 25 mM CO23- (25 mF), PO34-, Zn2+ and Cu2+ at pH 7 was determined for L = EDTA, DTPA, DOTA, HP-DO3A, and DO3A. Gd(EDTA)- and Gd(DTPA)2- reacted (greater than 20% in 10 min) with Cu2+ and Zn2+ in the presence of PO34-. These double replacement reactions yielded precipitated GdPO4 and chelated Cu(L). Gd(HP-DO3A), Gd(DO3A) and Gd(DOTA)- were inert to reaction with all four ions at room temperature (less than or equal to 1% reaction detected). The thermodynamic binding constants of the ligands for Gd3+ and Cu2+ were found to be equal (10(20) M-1) for DO3A, while DOTA and HP-DO3A favored Gd3+ over Cu2+ by greater than or equal to 10(2) M-1. The low order of reactivity of Gd(DOTA)- and Gd(HP-DO3A) was anticipated by the binding constants, but the lack of reactivity of Gd(DO3A) is attributed to kinetic inertia. This latter property, desirable in MRI contrast agents, is promoted by the conformational stability of the tetraazacyclododecane macrocycle, which forms the backbone of the ligand. It is concluded that this class of chelates is exceptionally inert in solutions of endogenously available ions, and that thermodynamics alone is an insufficient predictor of the reactivity of the highly inert Gd complexes based on the tetraazamacrocycle.

Contrast Media↗
PubMed1991

Tone-dependent waterfall behavior during venous pressure elevation in isolated canine hearts.

We examined the "vascular waterfall" hypothesis, which proposes that coronary flow is unaffected by elevations in outflow pressure until the latter reaches a critical threshold level, in 29 isolated canine hearts. In fibrillating hearts vasodilated with adenosine or carbocromen, coronary flow and the coronary pressure-flow relation were not affected by changes in great cardiac vein pressure (PGCV) below a threshold value of 11 +/- 0.9 (mean +/- SEM) mm Hg. Further elevations of PGCV reduced flow and shifted the pressure-flow relation to the right, increasing its pressure-axis intercept (Pf=0). When vasomotor tone was augmented with vasopressin, threshold PGCV increased to 25 +/- 2.7 mm Hg (p less than 0.001). Once again, the pressure-flow relation was unaffected by changes in PGCV below the threshold value and shifted to the right when this value was exceeded. The amount by which spontaneous values of Pf=0 exceeded threshold values of PGCV was greater when vasomotor tone was augmented than during vasodilation. Pf=0 continued to exceed PGCV when the latter was raised above the threshold level. Both Pf=0 and threshold values of PGCV were less during a long diastole than during ventricular fibrillation. We reached the following conclusions. 1) During changes in PGCV below a threshold value, the coronary circulation exhibits traditional waterfall behavior. 2) The threshold pressure for altering waterfall behavior is affected by vascular tone and mechanical activity. 3) Pf=0 remains above PGCV when the latter is increased above the threshold value needed to alter flow.

Animals↗
PubMed1991

Treatment of chronic pain by epidural spinal cord stimulation: a 10-year experience.

Epidural spinal cord stimulation by means of chronically implanted electrodes was carried out on 121 patients with pain of varied benign organic etiology. In 116 patients, the pain was confined to the back and lower extremities and, of these, 56 exhibited the failed-back syndrome. Most patients were referred by a pain management service because of failure of conventional pain treatment modalities. Electrodes were implanted at varying sites, dictated by the location of pain. A total of 140 epidural implants were used: 76 unipolar, 46 Resume electrodes, 12 bipolar, and six quadripolar. Patients were followed for periods ranging from 6 months to 10 years, with a mean follow-up period of 40 months. Forty-eight patients (40%) were able to control their pain by neurostimulation alone. A further 14 patients (12%), in addition to following a regular stimulation program, needed occasional analgesic supplements to achieve 50% or more relief of the prestimulation pain. Pain secondary to arachnoiditis or perineural fibrosis following multiple intervertebral disc operations, when predominantly confined to one lower extremity, seemed to respond favorably to this treatment. Uniformly good results were also obtained in lower-extremity pain secondary to multiple sclerosis. Pain due to advanced peripheral vascular disease of the lower limbs was well controlled, and amputation below the knee was delayed for up to 2 years in some patients. Pain due to cauda equina injury, paraplegic pain, phantom-limb pain, pure midline back pain without radiculopathy, or pain due to primary bone or joint disease seemed to respond less well. Patients who responded to preliminary transcutaneous electrical nerve stimulation generally did well with electrode implants. Notable complications included wound infection, electrode displacement or fracturing, and fibrosis at the stimulating tip of the electrode. Three patients in this series died due to unrelated causes. Epidural spinal cord stimulation has proven to be an effective and safe means of controlling pain on a long-term basis in selected groups of patients. The mechanism of action of stimulation-produced analgesia remains unclear; further studies to elucidate it might allow spinal cord stimulation to be exploited more effectively in disorders that are currently refractory to this treatment modality.

Chronic Disease↗
PubMed1991

Changes observed in antioxidant system in the blood of postmenopausal women with breast cancer.

From experimental studies and epidemiological data, it can be inferred that lipid peroxidation is increased in cancer patients. Cases of post-menopausal, untreated women with benign and malignant breast tumours, were compared with their age matched controls in their serum lipid peroxides, antioxidant vitamins (E and C), serum selenium and serum ceruloplasmin. Erythrocyte and its membrane lipid peroxidation and antioxidant enzymes (catalase, superoxide dismutase, glutathione peroxidase and glutathione-S-transferase) levels were also analyzed. Significant increase in circulating lipid peroxides, ceruloplasmin and significant decrease in antioxidant vitamins and selenium were observed in breast cancer women. The erythrocyte and its membrane lipid peroxidation was increased significantly and severe impairment of antioxidant potential was observed in breast cancer women.

Aging↗
PubMed1991

Studies on the changes in plasma lipids and lipoproteins in patients with benign and malignant breast cancer.

Experimental studies and epidemiological data suggest that, high fat diet increases the risk of developing breast cancer, both in animal and in human population. Cases of postmenopausal, untreated women with malignant and benign breast tumors, were compared for their age, body weight, plasma lipid fractions and lipoproteins. There was a significant increase in body weight, total plasma lipids, total cholesterol, LDL--cholesterol, VLDL--cholesterol, phospholipids, triacylglycerols, free fatty acids in malignant breast cancer patients. HDL--cholesterol had been significantly decreased in benign and malignant patients when compared with the control subjects.

Body Weight↗
PubMed1991

The effects of antihypertensive agents on the quality of life in Indian hypertensives.

Effects of commonly used antihypertensive agents like nifedipine, atenolol, propranolol and captopril on quality of life was studied. Fourty-four patients with essential hypertension entered and 26 completed the full protocol of the study. Each drug was given separately in a random fashion in fixed dosage for 4 weeks with a washout period of 2 weeks in between the drugs. Assessment of quality of life was done under following measures: satisfaction with life and sense of well being, physical state, emotional state, intellectual function, social life and sexual life; each assessed on a prestandardized 5 point scale. All the 4 drugs resulted in significant and similar blood pressure control but the incidence of adverse effects was maximum with nifedipine (40.9%), followed by atenolol (18.4%), propranolol (14.3%) and captopril (3.6%). There was significant improvement in various aspects of quality of life with all the 4 drugs. Captopril and propranolol scored significantly better than atenolol and nifedipine on measures like sense of well being and satisfaction with life, physical state, intellectual function and emotional state. Improvement in sexual life was maximum with captopril, moderate with propranolol and nifedipine and least with atenolol. In conclusion, captopril closely followed by propranolol was the most acceptable drug with fewer adverse effects and improved sexual as well as other aspects of quality of life compared to nifedipine and atenolol.

1-Propanol↗
PubMed1990

Use of interactive videodisc for teaching of pathology laboratory cases.

Images from a generic videodisc called the 'Slice of Life' were utilized to develop computer-assisted interactive videodisc instruction (IVI) units for supplemental independent review of the laboratory cases studied in the general pathology course for year 1 medical students. Four units based on laboratory cases (two on 'inflammation' and two on 'neoplasia') were developed for a dual-screen Macintosh system. With this dual-screen system, specific picture frames from the videodisc could be retrieved on one screen while the other screen displayed the corresponding text. Each unit contained a number of case studies, each of which consisted of a clinical profile, gross picture and description of the tissue removed, sequential photomicrographs at successively higher magnifications from various fields of slides and their descriptions, comparison with the normal histology of the organ involved, interpretation of the observations and comments, final diagnosis, and a quiz at the end. Histopathological features were specifically emphasized. Evaluation of the units obtained from three consecutive classes of students indicated that these units were received as valuable supplemental tools for independent review of the laboratory cases.

Computer-Assisted Instruction↗
PubMed1990

Deep brain stimulation for control of intractable pain in humans, present and future: a ten-year follow-up.

Deep brain stimulation with chronically implanted electrodes has provided satisfactory control of pain in patients with intractable chronic pain syndromes, which have been refractory to medication and other conventional modalities of management. In this series the authors present their experience with 48 patients who have been followed for periods ranging from 6 months to 10 years. Long-term pain control was achieved in 30 patients (63%). Both the periventricular gray and specific sensory thalamic nuclei have been used as targets. Our results indicate that there is an initial 2-year fall-off of pain control caused by idiopathic tolerance, with stable results thereafter, regardless of site of the implant. This is suggestive of some biochemical modification of tissues around the electrode. Patients with failed-back syndrome secondary to multiple disc operations fared well; those with pain secondary to progressive neurological disorders or cancer had only short-term pain relief, and those with thalamic pain, cauda equina injury, or phantom limb pain usually had a poor result. Deep brain stimulation, in selected patients, appears to provide long-term pain control safely with few side effects or complications.

Adult↗