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Biomedical subjects

N Kumar

Publications and source records attributed to N Kumar.

At least 73 records · Page 4Linked to original sources
PubMed1994

Pulmonary autograft for aortic valve replacement in rheumatic disease--an ideal solution?

The use of pulmonary autograft for aortic valve replacement (Ross procedure) offers an excellent option for the younger patient with its potential for growth and long term viability. We report our experiences of 61 patients with a mean age of 17.0 years undergoing Ross procedure over a four year period. Rheumatic disease was the cause of aortic valve disease in 48 (79.0%) patients. Mitral valve surgery was required in 18 (29.5%) patients. There was no hospital death, endocarditis or thromboembolism in the series. There was one late death from non-cardiac cause and three (4.9%) reoperations. Two of the reoperations were for progressive autograft regurgitation whilst the third was for mitral valve repair failure. Echocardiographic profiles of 37 of these patients followed beyond six months after surgery show a tendency towards progression of the autograft regurgitation. The long term effects of rheumatic disease on the transplanted valves remain to be evaluated.

Adolescent↗
PubMed1993

Expression of members of the heat-shock protein 70 family in the exoerythrocytic stages of Plasmodium berghei and Plasmodium falciparum.

Exoerythrocytic stages of Plasmodium berghei cultured in HepG2-A16 hepatoma cells and those of P. falciparum in human hepatocytes transplanted under the kidney capsule of CB-17/ICr scid/scid mice were used to evaluate expression of heat-shock-related stress proteins. Although undetectable in the sporozoites, the expression of proteins similar in sequence of a heat-shock protein of 70 kDa and a glucose-regulated protein of 78 kDa was markedly induced in the hepatic stages of malaria parasites. Expression of these proteins in the exoerythrocytic stages of the malaria parasite warrants a systematic evaluation of their potential role in eliciting cellular immune responses directed against infected hepatocytes.

Animals↗
PubMed1993

Nifedipine attenuates the hypertensive response to tracheal intubation in pregnancy-induced hypertension.

Thirty women with pregnancy-induced hypertension (PIH) scheduled for Caesarean section under general anaesthesia were studied to evaluate the efficacy of sublingual nifedipine in attenuating the pressor response to laryngoscopy and tracheal intubation. The patients were randomly given either the contents of a nifedipine capsule 10 mg or placebo sublingually 20 min before induction of anaesthesia. Blood pressure and heart rate were recorded at various time intervals. There was a decrease in mean arterial blood pressure (MAP) after pretreatment with nifedipine (P < 0.01). The increase in MAP during laryngoscopy and intubation was higher in the control group compared with nifedipine pretreatment group (P < 0.01). During laryngoscopy and intubation, MAP decreased by 3 mmHg in the nifedipine pretreatment group, while there was an increase of 14 mmHg in the control group. Heart rate increased in both the groups during the laryngoscopy and tracheal intubation (P < 0.01) but the increase was higher in the nifedipine group than in the control group (P < 0.05). Neonatal Apgar scores in both the groups were comparable. These results suggest that sublingual nifedipine is effective in attenuating the hypertensive response to laryngoscopy and intubation but not the tachycardiac response in parturients with PIH.

Administration, Sublingual↗
PubMed1993

Triple-valve operation in the young rheumatic patient.

Multiple-valve operation for the young rheumatic patient remains a problem. There is a paucity of information on the results of repair versus replacement in this age group. Between July 1988 and December 1991, 242 patients less than 20 years of age underwent a valve operation for rheumatic heart disease at our institution. Twenty-four (9.9%) of them had simultaneous mitral, aortic, and tricuspid valve procedures. The mean age was 14.71 years. All 24 patients were in functional class III or IV preoperatively. Valvar regurgitation was the predominant lesion. Four patients (16.7%) had active rheumatic myocarditis at the time of operation. Valve repair was attempted in the absence of infective endocarditis. Triple-valve repair was possible in 12 patients (50%). The hospital mortality rate was 16.7%. Reoperation was performed after repair in 9 patients (45%) without any deaths. The reason for reoperation was failure of the mitral valve repair in all patients, and the cause was technical in 3 patients, progression or recurrence of rheumatic myocarditis in 5, and endocarditis in 1 patient. The three late deaths (15%) were in patients who had mitral valve replacement. Valve repair was associated with a higher reoperation rate, and replacement of left-sided valves was associated with a higher early and late mortality. In conclusion, although valve repair would be ideal in the young rheumatic patient, multiple-valve repair is associated with a high reoperation rate.

Adolescent↗
PubMed1993

Molecular cloning and localization of an abundant novel protein of Plasmodium berghei.

Screening of Plasmodium berghei genomic libraries using DNA insert corresponding to the 3' half of P. falciparum 70-kDa heat shock protein gene identified several abundant clones which represent a novel gene in the parasite. The complete sequence was obtained using an approach based on inverse polymerase chain reaction. Analysis of the deduced amino acid sequence revealed the presence of 19 imperfect repeats of the sequence Gly-Gly-Met-Pro toward the carboxy terminus. Except for the similar sequence repeated seven times in the malarial 70-kDa heat shock protein, the sequence of the cloned gene product is very different. Moreover, the sequence also revealed acidic and basic domains in the protein which are more than 60% similar in sequence to functional domains present in numerous DNA binding transcription factors. A 56-kDa protein was identified by immunoprecipitation from labeled P. berghei extract using antisera raised in mice against gene products expressed in Escherichia coli. The protein is present in all the different life cycle stages of the parasites as revealed by immunoelectron microscopy.

Amino Acid Sequence↗
PubMed1993

Topical phenytoin in the treatment of split-thickness skin autograft donor sites: a comparative study with polyurethane membrane drape and conventional dressing.

The effectiveness of topical phenytoin as a wound healing agent was compared with that of OpSite (Smith & Nephew) and a conventional topical antibiotic dressing (Soframycin, Roussel) in a controlled study of 60 patients with partial-thickness skin autograft donor sites on the lower extremities. Mean time to complete healing (complete epithelialization) was 6.2 +/- 1.6 days in the phenytoin-treated group (30 patients), compared to 8.6 +/- 2.2 days with OpSite (15 patients), and 12.6 +/- 3.4 days in the 15 Soframycin-treated patients. The differences between the treatment groups were significant at P < 0.001. Mean pain scores were also lower in the phenytoin-treated group, 0.40 +/- 0.55 vs. 0.66 +/- 0.60 with OpSite (P < 0.05) and 1.4 +/- 0.50 with the conventional dressing (P < 0.001). Both phenytoin and OpSite were superior to the Soframycin dressing with respect to bacterial contamination and wound infection as measured by Gram stains of wound smears, swab and aspirate (OpSite) cultures, and clinical assessments (P < 0.001) carried out on the fifth day of treatment. No local or systemic adverse effects of the three agents used were noted. Phenytoin appears to be an effective, low-cost and safe method for the treatment of partial-thickness skin graft donor sites, comparing very favourably with, and in some aspects superior to, occlusive dressings. Further clinical use and evaluation of topical phenytoin are merited.

Administration, Topical↗
PubMed1993

Case report: ultrasound demonstration of traumatic fracture of the pancreas with pancreatic duct disruption.

Fracture of the pancreas is a rare injury caused by blunt abdominal trauma. Abdominal CT is probably the best modality for the detection of this uncommon injury. Ultrasonography is excellent for demonstrating an accompanying pseudocyst, but it is otherwise considered less effective than CT in the evaluation of pancreatic trauma. We report a case where we were able to demonstrate a fracture through the body of the pancreas along with disruption of the pancreatic duct, using a conventional ultrasound scanner.

Adult↗
PubMed1993

Congenital aneurysm of the muscular interventricular septum.

Cardiac aneurysms are rare in the paediatric age group, and are classified as congenital when the aetiology cannot be demonstrated. We report a 1-year-old patient with a congenital aneurysm of the muscular interventricular septum. Ventricular septal aneurysmectomy was performed successfully.

Echocardiography↗
PubMed1993

New perspectives on the affordability of long-term care insurance and potential market size.

A study of over 6,000 elderly long-term care insurance purchasers shows that the typical policy sold costs $102 per month, covers 5 years of nursing home care and pays $69 per day in benefits. Close to one-third of the purchasers have incomes less than $20,000, most (63%) use some savings to pay for premiums, 37% spend more than 5% of income on policies. Most nonpurchasers cited reasons unrelated to policy cost to explain why they did not buy a policy.

Age Factors↗
PubMed1993

Induction of male sexual behavior in the rat by 7 alpha-methyl-19-nortestosterone, an androgen that does not undergo 5 alpha-reduction.

The synthetic steroid 7 alpha-methyl-19-nortestosterone (MENT) binds with high affinity to the androgen receptor and exerts biological effects at some peripheral target tissues with a potency greater than that of naturally occurring androgens. In vivo, MENT does not undergo enzymatic 5 alpha-reduction and as a consequence, its biologic action on prostate and other organs of the male reproductive tract is not amplified as is that of testosterone (T). Thus, in castrated rats, a dose of MENT that will maintain normal muscle mass and gonadotropin levels will not maintain normal prostate and seminal vesicle weights. To investigate the ability of MENT to restore male sexual behavior in castrated rats, varying doses of MENT acetate were administered for 4 wk by use of s.c. mini-osmotic pumps. Animals treated with T acetate (200 micrograms/day) and nontreated intact animals served as positive controls, while a group of animals receiving vehicle alone were the negative controls. Steroid acetates are rapidly converted to T and MENT in blood. Appropriate steroid delivery was assessed by measurement of serum androgen concentrations. Male behavioral parameters were recorded twice per week. At the end of treatment, the weights of sex accessory organs were also recorded. The administration of MENT acetate at daily doses of 100 micrograms and 10 micrograms induced full copulatory behavior in a manner similar to that observed with doses of 200 micrograms T acetate.(ABSTRACT TRUNCATED AT 250 WORDS)

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗