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Biomedical subjects

N Kumar

Publications and source records attributed to N Kumar.

At least 163 records · Page 9Linked to original sources
PubMed1997

Where angels fear to tread? Mapping women and men in India.

"The authors have produced the ¿Atlas of Women and Men in India', using material from the 1991 Census, mainly at district level. The Atlas may be unacceptable to Indian geographers because it seeks to question the authority of numerical data and of maps, and to Western geographers because this is ¿mapping before we understand the process'. The authors introduce maps of the sex ratio in India and explore through a map of changes in the sex ratio 1981-91 some numerical, analytical, and ethical problems of such mapping. The Indian feminist activists consulted want the Atlas for advocacy: does this justify its production?"

Asia↗
PubMed1997

Use of intermediate acting muscle relaxants by infusion: the future.

The usefulness of newer intermediate-acting muscle relaxants rocuronium and cisatracurium when used by infusion has been reviewed briefly and their main features pointed out. Comparative features of atracurium, vecuronium and mivacurium have also been described. Both new agents may have advantages for use by infusion particularly for longer procedures, due to the lack of detectable metabolites with rocuronium and production of comparatively smaller amounts of metabolites with cisatracurium.

Androstanols↗
PubMed1997

Mycotic keratitis in children: epidemiologic and microbiologic evaluation.

PURPOSE: To evaluate the demographic features, clinical profile, and laboratory diagnosis in cases of mycotic keratitis in children. METHODS: We retrospectively analyzed 211 cases of mycotic keratitis in children younger than 16 years over a 5-year period in a tertiary eye center. Culture-proven cases of fungal keratitis were reviewed. RESULTS: Trauma was the most common predisposing factor (55.3%), followed by associated systemic illness (11.2%), previous ocular surgery (9.8%), and others. Corneal injury contaminated with vegetable matter was responsible for 60.5% of traumatic cases. Aspergillus species were the most frequent isolates (39.5%). Others included Fusarium (10.7%), Alternaria (10.2%), Curvularia (7.4%), and Penicillium (7%). A seasonal variation in the incidence of mycotic keratitis revealed a peak incidence in the months of September and October. One hundred sixty-two children (76.7%) cooperated for examination and scraping under topical anesthesia with or without sedation. General anesthesia for scraping was required in 49 (23%) of 211 children for corneal scraping. Gram stains of corneal scraping were positive for hyphal elements in 54.5% of cases, and potassium hydroxide wet-mount preparation was positive in 90.2% of cases. CONCLUSIONS: This study highlights important risk factors and organisms responsible for mycotic keratitis in children.

Adolescent↗
PubMed1997

The changing face of long-term care insurance in 1994: profiles and innovations in a dynamic market.

This study examines buyers and nonbuyers of long-term care insurance. The findings show that consumers purchased more comprehensive products in 1994-95 than they did in 1990, and that they appeared to get better value for the premium dollar. While annual sales are increasing at a rate of 25%, the market for long-term care insurance remains small, and many of the market barriers that existed four to five years ago persist today. These include confusion about public coverage, concerns about the adequacy of products and how to choose them, policy cost, and inadequate information about potential risk for needing long-term care. As states target limited public funds toward the indigent, older middle-class people will have to deal with exposure to risk for long-term care, and insurance may be one way to minimize this exposure.

Age Factors↗
PubMed1996

Further characterization of a 58 kDa Plasmodium berghei phosphoprotein as a cochaperone.

Molecular chaperones are important for proper protein folding during protein biogenesis. This report describes a protein from Plasmodium berghei which is 30% identical and 40% similar to a recently described mammalian cochaperone, or heat shock protein 70 interacting protein. The P. berghei cochaperone accumulates throughout the trophozoite stage and decreases during the schizont stage. The stage specific expression is consistent with its presumed role in protein folding or protein-protein interactions. The largest difference between the Plasmodium and mammalian sequences is a more extensive domain of imperfect glycine-glycine-methionine-proline (GGMP) tandem repeats in the parasite's cochaperone sequence. Immunofluorescence studies show that the protein is an abundant cytosolic protein of the parasite. However, antibodies raised against the GGMP repeat domain, which is also found in other parasite chaperones, react with both the parasite and host erythrocyte membrane. The reactivity with the host membrane suggests that the parasite exports molecular chaperones into the infected erythrocyte.

Amino Acid Sequence↗
PubMed1996

Clear cell hidradenoma simulating breast carcinoma: a diagnostic pitfall in fine-needle aspiration of breast.

Clear cell hidradenoma, a benign tumor of sweat gland, presented as a breast lump with ulceration of overlying skin in an elderly woman. Failure to identify its cytological features led to a wrong diagnosis of breast carcinoma on fine-needle aspiration of the lump. Retrospective review of cytology revealed the presence of many clear cells amidst polygonal tumor cells, but no tubular lumina were seen. Accurate diagnosis remains a problem.

Adenoma, Sweat Gland↗
PubMed1996

Effects of testosterone and 7 alpha-methyl-19-nortestosterone (MENT) on sexual and aggressive behaviors in two inbred strains of male mice.

Behavioral and endocrine effects of a synthetic androgen, 7 alpha-methyl-19-nortestosterone (MENT), which is not 5 alpha-reduced to dihydrotestosterone, were compared to those of testosterone in two inbred strains of male mice, C57BL/6J and DBA/2J, in two experiments. In the first experiment, seminal vesicle (SV) weights, kidney weights, and circulating steroid levels were examined in castrated mice treated with three doses of testosterone (3.125, 12.5, or 50 micrograms/day) or four doses of MENT (1, 4, 16, or 64 micrograms/day) for 2 weeks to determine the optimal replacement levels of the two androgens for behavioral studies. Both testosterone and MENT dose-dependently increased the SV weights that were greatly reduced, in both strains, by castration. MENT was more effective than testosterone in increasing SV weights, fully restoring them to intact levels in both strains, at the dose of 4 micrograms/day. At the dose of 12.5 micrograms/day, testosterone restored the SV weights completely in C57BL/6J and up to 80% in DBA/2J mice. DBA/2J mice were more sensitive than C57BL/6J mice to both androgens, as measured by kidney weights, although circulating levels of either steroid were very similar between the two strains of mice. In the second experiment, we investigated the effects of testosterone (12.5 micrograms/day) and MENT (4 micrograms/day) on sexual and aggressive behaviors. In each strain, MENT-treated and testosterone-treated mice showed similar numbers of mounts or intromissions. MENT was equally effective as testosterone to fully (C57BL/6J) or partially (DBA/2J) restore sexual behaviors as well as the SV weights to the intact levels. In contrast, MENT-treated mice of both strains were much less aggressive than testosterone-treated mice. In both C57BL/6J and DBA/2J mice, testosterone fully restored aggression to the intact levels as measured by aggression latency, number of aggressive bouts, and duration of aggression, whereas aggressive behaviors of the MENT-treated groups were not different from those of the castrated control groups. These results suggest that MENT can restore both male sexual behaviors and reproductive organ weights as effectively as testosterone, at one-third of the testosterone dose, without stimulating male aggressive behaviors.

Aggression↗
PubMed1996

7 alpha-methyl-19-nortestosterone facilitates sexual behavior in the male Syrian hamster.

Steroid hormones from the testes promote attraction to estrous females and facilitate copulation in the male Syrian hamster. We compared the ability of testosterone (T) and MENT, a potent synthetic androgen that does not undergo 5 alpha-reduction, to maintain sexual behavior in castrated males. Steroid treatment was initiated immediately after castration at three levels by means of Alzet osmotic pumps in sexually experienced adult male hamsters. Daily doses were 5, 25, or 100 micrograms T and 1, 5, or 25 micrograms MENT (n = 5/group). Additional castrated males (n = 5) remained untreated. Sexual behavior was recorded during two 10-min tests before, and at 2, 4, 6, and 8 weeks after orchidectomy. MENT and T maintained equivalent levels of behavior at each corresponding dose of androgen (high, medium, or low). The low dose of T or MENT failed to sustain mating behavior. Eight weeks after castration, males receiving the high and medium doses of androgens continued to express intromissions and ejaculations at gonadally intact levels. However, only males receiving the high dose showed anogenital investigation at the same level as intact males. From these data, we conclude that MENT sustains mating behavior in the male hamster, and that chemoinvestigatory behavior requires higher levels of androgens than those necessary for copulation.

Animals↗
PubMed1996

Diagnosis and outcome of isolated rectal tuberculosis.

PURPOSE: Segmental colonic tuberculosis commonly involves the ascending, transverse, or sigmoid colon. Rectal involvement in tuberculosis is uncommon and poorly characterized. This study describes the clinical presentation, endoscopic features, and outcome of isolated rectal tuberculosis. METHODS: Isolated rectal tuberculosis was defined as focal lesions of the rectum in the absence of radiologically demonstrable lesions in the small and large bowel on barium contrast studies. Diagnosis of rectal tuberculosis was based on characteristic endoscopic appearance of lesions, histopathologic features of tuberculosis in biopsy/ resected material, and response to antitubercular therapy. RESULTS: Eight patients with rectal tuberculosis were seen during a four-year period at our hospital. Hematochezia was the most common presenting feature (88 percent), followed by constitutional symptoms (75 percent) and constipation (37 percent). Rectal examination revealed a tight stricture within 10 cm of the anal verge in seven patients. Barium enema showed stricture of variable length, with focal areas of deep mucosal ulceration and increase in presacral space. Proctoscopic findings were tight stricture (7), nodularity with ulceration (6), and multiple aphthous ulcers (1). Granulomatous infiltration was detected in seven of eight patients in biopsy material obtained at endoscopy (6) or surgery (1). Cessation of hematochezia, resolution of constitutional symptoms, and weight gain were seen in all patients following treatment with antitubercular drugs. CONCLUSION: Our data suggest that tubercular involvement of rectum, although uncommon, is an important cause of rectal strictures in India. Response to antitubercular chemotherapy is uniformly good, and surgery is seldom required in these patients.

Adolescent↗
PubMed1996

Neostigmine but not edrophonium prolongs the action of mivacurium.

PURPOSE: To examine the influence of anticholinesterase drugs neostigmine and edrophonium (which have different effects on plasma cholinesterase activity) administered for antagonism of neuromuscular block on the duration of action of mivacurium (a neuromuscular blocking drug metabolised by plasma cholinesterase). METHODS: This was a randomized study where mivacurium 0.15 mg.kg-1 was administered to a control group or after administration of neostigmine 40 micrograms.kg-1 or edrophonium 1 mg.kg-1 (n = 10 for each group) administered 10 min earlier for antagonism of atracurium-induced neuromuscular block. Neuromuscular block was measured by stimulation of the ulnar nerve in a train-of-four mode (TOF) and measuring the force of contraction of the adductor pollicis muscle. Baseline plasma cholinesterase activity was estimated before drug administration in all the groups and following anticholinesterase administration. RESULTS: The times to recovery of T1 (first response in the TOF) to 25 and 90% of control and of the TOF ratio to 0.7 after 0.15 mg.kg-1 of mivacurium were 47, 65 and 70 min in the neostigmine group; 25, 36 and 36 min in the edrophonium group and 17, 29 and 27 min respectively in the control group (P < 0.01). The plasma cholinesterase activity (PCHE) after neostigmine decreased from 6596 to 1959 U.L-1 (P < 0.001) but there was no change after edrophonium (6140 to 6396 U.L-1). CONCLUSIONS: The duration of action of mivacurium is prolonged by previous administration of neostigmine and this is most likely to be due to inhibition of PCHE activity.

Adolescent↗
PubMed1996

Comparison of the effect of left ventricular volume and pressure overload on beta-adrenoceptor density in left heart valvular disease.

The sympathetic responses in left heart valvular disease may depend on the ventricular load conditions. We proposed to evaluate this possibility by comparing the effects of left ventricular pressure (LVP) and volume (LVV) overload on beta-adrenoceptor density and ligand binding affinity in lymphocytes and in the four myocardial chambers in rheumatic heart valvular patients. Receptor activity was determined by radioligand binding using [125I]iodocyanopindolol. In the lymphocytes (n = 45), the beta-adrenoceptor density was reduced by 88% (P < 0.001) in LVP patients (n = 15) and 79% (P < 0.001) in LVV patients (n = 30) compared with 23 controls. In the myocardium, the receptor density of the LVP (n = 12) was attenuated by 55% (P < 0.05) in the left ventricle, 42% in the right ventricle, 13% in the left atrium, and 37% in the right atrium, while in LVV patients (n = 22) it decreased by 73% (P < 0.01) in the left ventricle, 62% (P < 0.05) in the right ventricle, 30% in the left atrium, and 34% in the right atrium compared with 15 controls. Thus, the reduction in density was greatest in lymphocytes and least in the atria in both groups. The decrease in ventricular density of the LVV group was similar to the reduction in the lymphocytes and two-fold higher than in the atrial density. These alterations were significantly greater for the LVV than for the LVP group. The Kd for the myocardial receptor binding to [125I]iodocyanopindolol was not significantly influenced in either group, but was lower in the lymphocytes. These findings suggest that in patients with left heart valvular disease, there is a significant attenuation in both peripheral and myocardial beta-adrenoceptor density. The decrease in receptor density is significantly greater in the left ventricular volume overload than in the left ventricular pressure overload patients.

Adolescent↗
PubMed1996

Effect of left ventricular pressure and volume overload on alpha-adrenoceptor activity in patients with rheumatic heart valvular disease.

We have investigated the possibility that the various left ventricular load conditions may exert different effects on the sympathetic function by comparing the influence of volume (VOL) and pressure (POL) overload on platelet alpha-adrenoceptor activity, plasma catecholamines and cAMP in 44 patients with rheumatic heart valvular disease. Receptor activity was determined by radioligand binding methods, catecholamines by HPLC using an electrochemical detector, and cAMP by radioimmunoassay. The mean alpha-adrenoceptor density (Bmax) of the control group (n = 29) was 4.71 +/- 0.41 fmol per 10(7) platelets and the corresponding dissociation constant (Kd) was 2.47 +/- 0.15 nM. In VOL patients, the density was elevated by 70% (P < 0.0001), but it remained unchanged in the POL patients. In contrast to the Bmax, the Kd of the VOL group was not changed, and it increased by 34% (P < 0.01) in the POL group. Norepinephrine was elevated by 91% (P < 0.05) in POL, and epinephrine increased by 65% (P < 0.05) in POL and 71% (P < 0.05) in VOL. These results suggest that the sympathetic nervous system responds to left ventricular volume overload by increasing alpha-adrenoceptor density with no apparent change in receptor affinity toward [3H]-yohimbine binding, and to left ventricular pressure overload by decreasing their binding affinity without a parallel decrease in receptor density. The increase in receptor density in VOL is accompanied by an increase in plasma epinephrine, and the decrease in binding affinity in POL is associated with increased plasma norepinephrine and epinephrine levels.

Adolescent↗
PubMed1996

Effects of different left ventricular load conditions on myocardial beta-adrenoceptor density in patients with rheumatic heart valvular disease.

1. The possibility that different left ventricular load conditions may influence myocardial beta-adrenoceptor function in various ways was evaluated by determining the receptor density in all four chambers of 69 patients with rheumatic heart valvular disease. 2. The left ventricular beta-adrenoceptor density was reduced by 44% in patients with left ventricular pressure overload (LVP), 66% in left ventricular volume overload (LVV), 56% in mixed volume and pressure overload (MOL), and 60% in those with no left ventricular pressure overload (NOL). Similarly, the right ventricular receptor density decreased significantly by 46%, 54%, 43%, and 46%, left atrial by 15%, 29%, 14%, and 21%; and right atrial by 27%, 30%, 28%, and 12% in LVP, LVV, MOL, and NOL, respectively. Thus, the general trend in the decrease in receptor density was LVV > MOL = NOL > LVP. 3. Furthermore, the LVV patients with the largest decrease in receptor density in all four chambers, similarly exhibited the largest ejection fractions (EF) and left ventricular internal diastolic and systolic diameters. 4. The results show that left ventricular volume overload is a major cause of attenuation in myocardial beta-adrenoceptor density, compared to other forms of ventricular overload in heart valvular disease. 5. Since elevated EF in volume overload patients is an indication of the severity of the disease, the decrease in their myocardial receptor density may be a reflection of the degree of influence of the disease on their sympathetic activity.

Adolescent↗
PubMed1996

Fine needle aspiration (FNA) cytology of pilomatrixoma.

FNA smears from five histologically confirmed cases of pilomatrixoma were reviewed to delineate the cytological features helpful in diagnosis. A combination of basaloid cells, ghost cells and foreign body giant cells appeared to be necessary in FNA smear for a confident cytodiagnosis of pilomatrixoma. Presence of naked nuclei, nucleated squamous cells and calcification were additional features in favour of the diagnosis. Another 10 cases with initial cytodiagnosis of pilomatrixoma or benign skin appendage tumour were reviewed. Using the above criteria, diagnosis of pilomatrixoma was easy in five cases. One case was problematical due to presence of atypical squamous cells. Initially the cytological features were most commonly confused with epidermal inclusion cyst, giant cell lesion or a squamous cell carcinoma. The main reasons for erroneous diagnosis were lack of awareness of cytological features, predominance of one component over the others, and non-representative FNA smears. Atypia in nucleated squamous cells, and misinterpretation of basaloid cells as malignant can lead to diagnostic dilemma. Adequate clinical data are also necessary.

Adolescent↗
PubMed1996

Duration of stabilization of control responses affects the onset and duration of action of rocuronium but not suxamethonium.

The effect of the duration of stabilization of control responses on the onset and duration of clinical relaxation of suxamethonium 1 mg kg-1 and rocuronium 0.6 mg kg-1 were investigated in 90 patients. The control responses were allowed to stabilize for 1, 5, 10, 15 or 20 min prior to administration of rocuronium and for 1, 5, 10 or 15 min prior to suxamethonium. The mean onset time for rocuronium decreased from 150 to 46 s as the duration of stabilization increased from 1 to 20 min (P < 0.001) although the maximal effect was observed within the first 5 min. The average duration of clinical relaxation also increased from 25 to 40 min (P < 0.001). No effect was observed for either variable in the case of suxamethonium.

Adolescent↗
PubMed1996

Potency and time course of action of rocuronium during desflurane and isoflurane anaesthesia.

We have studied the potency and onset and duration of action of rocuronium in patients anaesthetized with 1 MAC of desflurane or isoflurane (in 66% nitrous oxide). Potency was estimated using the single bolus dose technique. Neuromuscular block was measured by stimulation of the ulnar nerve and recording the force of contraction of the adductor pollicis muscle. The ED50 and ED95 of rocuronium were estimated as 138 (95% confidence limits 117-162) micrograms kg-1 and 281 (241-328) micrograms kg-1, and 126 (105-151) micrograms kg-1 and 283 (236-339) micrograms kg-1 during desflurane and isoflurane anaesthesia, respectively. The mean times to onset of maximum block after rocuronium 0.6 mg kg-1 were 1.0 (SD 0.10) min and 1.1 (0.15) min, respectively, during anaesthesia with desflurane and isoflurane. The respective times to recovery of T1 (the first response in the train-of-four (TOF) stimulation) to 25% and 90% were 36 (8.3) min and 54 (15.4) min during desflurane anaesthesia and 31 (8.2) min and 45 (12.7) min during isoflurane anaesthesia. The times to recovery of the TOF ratio to 0.7 were 66 (13.4) min and 52 (16.3) min and the 25-75% recovery indices 14 (5.3) min and 10 (3.2) min, respectively, in the desflurane and isoflurane groups. There were no differences in the estimated potency or onset of action of rocuronium during desflurane and isoflurane anaesthesia. However, duration of action tended to be longer curing desflurane anaesthesia although only the differences in times to TOF ratio of 0.7 and the recovery indices were close to being significantly different (P = 0.0503 and 0.0560).

Adolescent↗