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Biomedical subjects

P Kumar

Publications and source records attributed to P Kumar.

At least 451 records · Page 25Linked to original sources
PubMed1994

Cyanide induced changes in dynamic pulmonary mechanics in rats.

Effect of subcutaneously (s.c.) administered potassium cyanide (0.5 and 1.0 LD50) and inhalation of hydrogen cyanide (55 ppm or 60.6 mg/m3) for 30 minutes was studied on various physiological parameters related to dynamic pulmonary mechanics in anaesthetized rats. Total pulmonary phospholipid with its fractions were also estimated. Both s.c. (1.0 LD50) and inhalation exposures increased air flow, transthoracic pressure and tidal volume accompanied by significant decrease in pulmonary phospholipids. Inhalation of hydrogen cyanide also exhibited direct effect on the pulmonary cells as evidenced by decreased compliance. The study suggests that inhalation of cyanide is more injurious compared to parenteral route.

Animals↗
PubMed1994

Pattern of acute renal failure at a referral hospital.

Fifty two children (upto 12 years age) with acute renal failure (ARF) admitted to the Nephrology services between January, 1989 to August, 1992 were studied to determine the cause and outcome. Of these, 39 were boys and 13 girls; 27 (51.9%) patients were below 4 years of age. Hemolytic uremic syndrome (HUS) was the commonest cause of ARF (30.8%) followed by acute tubular necrosis (ATN) in 28.84% and acute glomerulonephritis in 19.23%. All patients had severe renal involvement with anuria in 53.6% and oliguria in 46.4% at presentation. HUS was the leading cause of anuria (53.6%), followed by obstructive uropathy (21.4%). Thirty five patients required dialytic support for a median duration of 18 days (2-90 days). The mortality was 34.6%. Seven patients of HUS, 4 patients of ARF following surgery, 3 patients each of ATN and glomerulonephritis and one patient of obstructive uropathy died. Anuria at onset, central nervous system or respiratory complications and delay in institution of dialytic support were bad prognostic factors. We conclude that early referral and prompt institution of dialytic support may be helpful in decreasing the mortality.

Acute Kidney Injury↗
PubMed1994

A study of childhood tetanus in post-neonatal age group in Delhi.

A study was conducted in tetanus in the postneonatal pediatric age group between January, 1989 and June, 1991. Clinical profile of 55 patients was studied and outcome during this period was compared with previous years (1986-88). Although, an overall decline in total admissions was noted, only a modest decline in mortality was observed. All the patients but one were either unimmunized or incompletely immunized. More than 40% patients were from Delhi. Otorrhea was common (49.1%) in these patients. Primary immunization with booster dose in the community is stressed. Children with aural discharge should be taken as a high-risk group for tetanus and be evaluated for immunization at first visit.

Child↗
PubMed1994

Effects of denervation and nerve crushing on chicken muscle.

When compared with the standard free muscle grafts, predenervated and nerve crushed chick gastrocnemius muscle grafts followed an identical and ordered sequence of tissue degeneration-regeneration. Atrophy of the fibres during ischaemic degeneration was accompanied by loss of weight, noncollagenous proteins and increment in lytic enzymes (acid and alkaline phosphatase), glucose 6-phosphatase, glycogen and succinate dehydrogenase. Regeneration was more rapid in standard free muscle grafts. Trophic insults to muscle via denervation and nerve crushing prior to transplantation did not influence graft renewal when compared with standard free muscle grafts though relatively increased recovery was shown by predenervated muscle grafts.

Animals↗
PubMed1994

IAA synergism and vitamin B1 antagonism with calcium for induction and growth of adventitious roots in branch cuttings of Dalbergia sissoo Roxb.

IAA induced adventitious roots in branch cuttings of D. sissoo, whereas vit. B1 promoted growth of these roots. A strong IAA synergism and vit. B1 antagonism with calcium was observed in induction and growth of adventitious roots. Treatments with IAA (571 microM) and calcium (134 microM) proved to be an ideal combination, exhibiting 87% rooting and 0.87 R/S ratio in branch cuttings, coupled with an increase of root length, root number, root fresh weight and root dry weight as compared to control.

Calcium↗
PubMed1994

Appearance of homogeneous smectic multilamellar microenvironments in biomembranes undergoing superoxide-initiated lipid peroxidation: lipid-dienyl radical accumulation and fluidity management in lipid bilayers.

Erythrocyte ghosts were exposed to various levels of oxyradical shock in order to identify the extent of accumulation of peroxidative intermediates. Malondialdehyde reacting end products were the same in all different models. But, the accumulation of dienyl radical species increased with higher intensity of oxyradical shock. These dienyl radicals may rearrange to create a homogeneous smectic multilamellar microenvironment which may be more fluid in terms of the molecular dynamics.

Erythrocyte Membrane↗
PubMed1994

A study of extra-auditory effects of noise.

Paper mill workers (106) exposed to noise ranging from 80 to 96 dBA were assessed for alteration in clinical status. Neurobehavioral functions were examined with the help of a questionnaire. The study did not reveal any changes attributable to noise in subjects exposed to 86-90 dBA and > 90 DBA noise in course of their occupations.

Adult↗
PubMed1994

Synthesis and antiinflammatory activity of 5-(1,6-dihydropyridyl)-tetrazol-2-acetic acids, esters and amides.

A series of 5-[3-(1,6-dihydropyridyl)]-2H-tetrazol-2-acetic acids (15-21), esters (7-14, 22-23) and amides (24-27) were synthesized in order to investigate the effect of alpha-substituents (R1 = H, Me) and 1,6-dihydropyridyl substituents (R2 = aryl, alkyl; R3 = phenoxy or amino) on antiinflammatory activity. Compounds having a R1 = H substituent generally exhibited greater activity. R2-aryl substituents showed higher potency except when R1 was Me in the acetic acid ester group of compounds. The relative potency order with respect to the R3-substituent was NH2 > PhO. When the R2-substituent was an aryl moiety, the effect of the R4-substituent on antiinflammatory activity was acid (R4 = OH) > or = ester (R4 = OMe), but when the R2-substituent was an alkyl group, the order of potency was generally ester > acid. Methyl 2-methyl-2-(5-[3-(6-i-butyl-1-phenoxycarbonyl-1,6-dihydropyridy l)]-2H- tetrazol-2-yl)acetate (13) was the most effective antiinflammatory agent in the group, reducing inflammation 93%, relative to ibuprofen's 52% inhibition, at 5 hr after a 100 mg/kg po dose.

Acetates↗
PubMed1993

Percutaneous balloon valvuloplasty in mirror-image dextrocardia and rheumatic mitral stenosis.

A 28-year-old woman with mirror-image dextrocardia and severe rheumatic mitral stenosis underwent successful percutaneous balloon mitral valvuloplasty (PBMV). Standard technique was altered to include transseptal catheterization via the left femoral vein and inter-atrial septal puncture with the transseptal needle rotated to a 7 o'clock position. The predilatation transmitral gradient (mean) of 16 mmHg decreased to 5 mmHg following PBMV. The valve area improved from 1.0 cm2 to 2.6 cm2. There were no complications. This case illustrates that transseptal catheterization can be accomplished safely in patients with unusual cardiac anatomy and mitral valvuloplasty can be performed in patients with mirror-image dextrocardia and rheumatic mitral stenosis.

Adult↗
PubMed1993

Time-dependent changes in the mechanical properties of zirconia ceramic.

Zirconia has received special attention, mainly because of its high strength and toughness. However, there is some controversy about the time-dependent deterioration of its mechanical properties. To examine the change in mechanical properties of zirconia ceramics in vivo and in vitro, tetragonal zirconia polycrystal pieces were introduced into the medullary cavity of the tibia in Japanese rabbits and animals were sacrificed after 2, 4 and 6 weeks and 6, 12, and 30 mo, respectively. Alumina ceramic and hydroxyapatite (HAP) pieces were used as controls to investigate the differences in biocompatibility. Zirconia showed a bending strength of over 1000 MPa initially, and little time-dependent change in strength was found in both in vivo and in vitro environments. x-Ray analysis showed little change in the transformation rate, i.e., less than 5 mol % in vivo and in vitro over a period of 3 years. To estimate time-dependent changes in zirconia over a longer period, zirconia pieces were placed in 95 degrees C saline solution for over 3 years and their mechanical properties examined at chosen intervals. No serious decrease of bending strength was found over the 3-year period under these conditions. It is concluded that zirconia can be used clinically because it retains a bending strength of over 700 MPa under any experimental conditions for over 3 years.

Animals↗