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Biomedical subjects

N Kumar

Publications and source records attributed to N Kumar.

At least 505 records · Page 28Linked to original sources
PubMedDate not supplied

Elective surgery for corrosive-induced gastric injury.

Gastric cicatrization is a well recognized late sequela of corrosive gastric injury, but the optimum timing and type of surgery for this complication are still unclear. Over a 7-year period (1988-1994) 34 patients underwent elective surgery for gastric lesions secondary to corrosive ingestion. A total of 18 (53%) patients had an associated esophageal stricture and presented with dysphagia, 15 (44%) patients had features of gastric outlet obstruction, 6 (18%) had diffuse gastric injury, and 28 (82%) had a segmental lesion. A tube jejunostomy was done in 23 (68%) patients to improve nutrition and resulted in a significant increase in weight and in the serum protein level after 8 weeks of tube feeding. Elective surgery was performed 3 to 24 months (average 7 months) after ingestion of the corrosive substance. Gastric resection was done in 20 (59%) patients and gastrojejunostomy (without vagotomy) in 11 (32%); at follow-up the latter group did not exhibit development of a stomal ulcer. In patients with an associated esophageal stricture, endoscopic dilatation was successful in 89% patients and simplified the surgical approach. In conclusion, the success of surgery for corrosive-induced gastric injury depends on selecting the right procedure and intervening at the appropriate time.

Acids↗
PubMedDate not supplied

Nestorone: a progestin with a unique pharmacological profile.

Nestorone(R) (Nestorone 16-methylene-17alpha-acetoxy-19-norpregn-4-ene-3,20-dione), formerly referred to as ST 1435, is a potent progestin when given parenterally via sustained release formulations. The pharmacological profile of Nestorone was compared with that of levonorgestrel and 3-keto-desogestrel by steroid receptor binding studies and by in vivo bioassays in rats and rabbits. 3-Keto-desogestrel showed the highest binding affinity to progesterone receptors (PR) followed by Nestorone, levonorgestrel, and progesterone. The binding affinity of Nestorone to androgen receptors (AR) was 500- to 600-fold less than that of testosterone. However, both levonorgestrel and 3-keto-desogestrel showed significant binding (40 to 70% of testosterone) to AR. None of the progestins bound to estrogen receptors (ER). The progestational activity of Nestorone, levonorgestrel, and progesterone was compared using McPhail index in immature rabbits and pregnancy maintenance and ovulation inhibition tests in rats after subcutaneous (s.c.) administration. In all three tests, Nestorone was the most potent progestin. The progestational activity of Nestorone was also compared after oral and s.c. administration in rabbits. The potency of Nestorone was over 100-fold higher upon s.c. administration than via the oral route. The androgenic activity of progestins, based on the stimulation of ventral prostate (androgenic target) and levator ani (anabolic target) growth in castrated immature rats, showed good correlation with their binding affinity to AR. Nestorone showed no androgenic or anabolic activity. Nestorone did not bind to sex hormone binding globulin (SHBG), whereas both levonorgestrel and 3-keto-desogestrel showed significant binding to SHBG. The estrogenic/antiestrogenic activity of Nestorone was investigated in immature ovariectomized rats. In contrast to estradiol and levonorgestrel, Nestorone showed no uterotropic activity in ovariectomized rats. Despite significant binding to glucocorticoid receptors (GR), Nestorone showed no glucocorticoid activity in vivo. It is concluded that a strong progestational activity, combined with lack of androgenic, estrogenic, and glucocorticoid-like activities, confer special advantages to Nestorone for use in contraception and hormone replacement therapy.

Animals↗
PubMedDate not supplied

Isolation of luteinizing hormone receptor binding inhibitor from ovine corpora lutea.

Procedures for the isolation of luteinizing hormone receptor binding inhibitor (LHRBI) from crude extracts of ovine corpora lutea are described. Microsomal pellets recovered by differential centrifugation of homogenates of fresh corpora lutea were stored at -20 degrees C for 3 weeks and then extracted with Tris-HCl buffer (pH 7.4). On sequential filtration of the extract on Amicon UM-20, PM-10 and UM-2R filters, the corresponding retentates (UM-20R, PM-10R and UM-2R) demonstrated inhibition of radio-labeled human chorionic gonadotrophin (hCG) to ovine luteal cells. The retentate of UM-2 filter (UM-2R) was further fractionated by reverse phase high pressure liquid chromatography. The active fractions- III, IX, X and XIII, thus obtained, calculated by their ability to inhibit 125I-hCG binding in dose dependent manner, were purified 150 to 1000-fold.

Animals↗
PubMedDate not supplied

Some observations on the role of LH receptor binding inhibitor of ovine corpora lutea in ovarian processes.

Preliminary studies, both in vitro and in vivo were carried out to understand the physiological significance of LH receptor binding inhibitors isolated from ovine corpora lutea. Among the four active fractions tested, while UM-2R-III administered intraperitoneally suppressed both hMG and hCG-induced stimulation of uterine weights in immature mice, UM-2R-IX reduced the hCG-induced uterine weight. Fraction UM-2R-III inhibited both FSH and LH-stimulated cyclic AMP production by rat granulosa cells. Intraperitoneal injections of UM-2R-III and IX to adult cycling rats on the day of proestrus partially blocked ovulation. Similar i.p. treatment of cycling rats in 2 doses on day 1 of diestrus, prevented implantation/or early pregnancy (on 10th day of pregnancy) in 70 to 80% of rats. As the plasma levels of progesterone were low in the treated animals compared to the control, the decrease was attributed to the inadequate development of the corpus luteum. Of these fractions, UM-2R-IX was more effective at 5 to 10 times less doses compared to UM-2R-III. Further studies are needed to assess the route and dose of administering the active LHRBR components.

Animals↗
PubMedDate not supplied

Corrosive oesophageal strictures following acid ingestion: clinical profile and results of endoscopic dilatation.

There are several reports on oesophageal strictures caused by alkali ingestion, but information on oesophageal strictures due to acid ingestion is scarce. Endoscopic dilatation, which has been found to be quite safe and effective in the treatment of benign oesophageal strictures of other aetiology, has also not been evaluated adequately in the treatment of these strictures. Over a period of 2 years, of 47 patients treated at this centre of benign oesophageal strictures, 17 (36.2%) patients had strictures following ingestion of corrosive agents. Thirteen patients had ingested acids and only four gave a history of alkali ingestion. The age range of these 13 patients was 14-50 years (mean = 25.5 years, s.d. = 2.6). The amount of acid ingested varied from 10 to 100 ml (median = 50 ml). The interval between acid ingestion and presentation to hospital ranged from 1 to 60 months (median = 2 months). Ten patients had multiple strictures, and the most common site of involvement was the upper third followed by the lower third of the oesophagus. Only five of these 13 patients had evidence of gastric involvement in the form of antral stricture (four) and hour glass deformity (one). Strictures were dilated using Eder-Puestow metal olives passed over a guide wire. The total number of sittings required to achieve adequate dilatation in this group ranged from 1 to 30 (median = 14). Most patients were managed successfully with dilatation (good response 63.6%, satisfactory response 18.2%). On follow-up, recurrence of dysphagia was seen in a high number of patients (66%), but this could be managed easily with repeat dilatation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

Phenytoin levels in catamenial epilepsy.

We studied the fluctuations in phenytoin (PHT) levels during ovulatory and menstrual phases of the cycle, in eight patients with catamenial epilepsy and in eight age-matched controls. Pharmacokinetic studies of PHT were done in five patients with catamenial epilepsy. The difference in PHT levels during menstrual and ovulatory phase in catamenial group was 3.44 +/- 3.25 micrograms/ml as compared with 0.91 +/- 2.03 micrograms/ml in controls. The mean fall during menstrual phase was significant (p less than 0.05) in the catamenial group. There was also rapid though statistically nonsignificant clearance of PHT during menses as compared with the ovulatory period. It is presumed that the fall in plasma PHT levels during menses, though still within therapeutic range, may be responsible for catamenial exacerbation of epilepsy.

Acute Disease↗
PubMedDate not supplied

Molluscum contagiosum. A case report with fine needle aspiration cytologic diagnosis and ultrastructural features.

BACKGROUND: Cytomorphologic and ultrastructural features of molluscum contagiosum, a rare skin lesion of viral etiology, are presented. CASE: A 4-month-old female was referred for fine needle aspiration cytology of papules over the back and chest wall. A Giemsa-stained preparation of whitish material aspirated from the chest wall nodule showed numerous large, intracytoplasmic, basophilic bodies that pushed the host cell nucleus to the periphery, giving a signet-ring appearance to a few cells. A cytologic diagnosis of molluscum contagiosum was suggested. On electron microscopy numerous intracytoplasmic viral particles were demonstrated, thus confirming the cytologic diagnosis. CONCLUSION: In clinically unsuspected cases, the cytologic diagnosis of molluscum contagiosum can be suggested by demonstrating pathognomonic molluscum bodies in aspirated material.

Biopsy, Needle↗
PubMedDate not supplied

Cytomorphology of filariasis revisited. Expansion of the morphologic spectrum and coexistence with other lesions.

OBJECTIVE: To review the cytomorphologic spectrum of the filarial worm and associated tissue response in 33 cases. STUDY DESIGN: Retrospective analysis was carried out in clinically unsuspected cases of filariasis diagnosed on cytology over a period of 10 years. Twenty-nine aspirate smears from 28 patients were air dried and stained with May-Grünwald-Giemsa stain. Four routine cervical smears and one centrifuged smear of urine were stained with Papanicolaou stain. RESULTS: Microfilariae alone and along with adult gravid females were present in 25 and 4 cases, respectively. In one case both adult male and female worms with microfilariae and eggs were seen. The diagnosis was based on the presence of eggs alone in one case and fragments of female worms in two. Four of these cases were neoplastic lesions, and microfilariae were found incidentally. In one case of splenomegaly microfilariae were seen along with Leishman-Donovan bodies. CONCLUSION: Filariasis can be diagnosed on cytology by demonstrating microfilariae, a male or female worm, or eggs alone. It can be seen in association with neoplastic lesions and rarely with other parasitic infections.

Adolescent↗
PubMedDate not supplied

Liesegang rings in cytologic samples accompanied by calcium oxalate-like crystals. A report of three cases.

BACKGROUND: The presence of Liesegang rings (LRs) in cytologic specimens is a morphologic curiosity. The exact mechanism of formation and composition of these peculiar rings is a mystery. Their morphologic resemblance to parasites is well recognized and illustrated. Their association with calcium oxalate-like crystals and their presence in a tubercular lymph node are described for the first time below. CASES: Giemsa-stained aspiration smears from an enlarged lymph node and two breast lumps showed purple rings of variable morphology resembling ova, larvae or adult parasites. Misdiagnosis of parasites was avoided by careful evaluation. In all three cases the LRs were associated with calcium oxalate-like crystals and were nonbirefringent. CONCLUSION: LRs can be mistaken for ova, larvae or adult parasites. Awareness of their varied morphology is helpful in avoiding misinterpretation and overdiagnosis of parasitic lesions. The coexistence of LRs and crystals was an unusual finding in this study.

Adult↗
PubMedDate not supplied

Gastric tuberculosis. Endoscopic cytology as a diagnostic tool.

OBJECTIVE: To highlight the utility of endoscopic brush smears in the diagnosis of gastric tuberculosis in clinically unsuspected cases. STUDY DESIGN: A retrospective analysis of endoscopic brush smears from 210 patients with gastric symptoms. In seven of these patients (3.3%) the possibility of gastric tuberculosis was suggested in Giemsa-stained smears. Biopsy was available in all cases. Ziehl-Neelsen stain to demonstrate tubercle bacilli was used in brush smears and biopsies in seven and three cases, respectively. RESULTS: Endoscopically the sites involved were antrum (two), pylorus (two), pylorus and duodenum (three). One patient had an ulcerative lesion, and six had growths. Granulomas and/or epithelioid cells were seen in brush smears in all cases. Tubercle bacilli could be demonstrated in cytologic smears in four cases. Endoscopic biopsy showed granulomas in five cases and non-specific gastritis in two. Tubercle bacilli could not be demonstrated in any of the biopsy sections. On further clinicoradiologic investigation, two patients were found to be follow-up cases of pulmonary and nodal tuberculosis. Enzyme-linked immunosorbent assay for HIV, done in three cases, was negative. A final diagnosis of primary gastric tuberculosis in five patients and secondary in two was considered. Six patients responded to antituberculosis treatment and showed healing of the lesions on repeat endoscopy after six months of therapy, while one was a recent case with four weeks' follow-up. CONCLUSION: Endoscopic brush cytology is a reliable modality for the diagnosis of gastric tuberculosis.

Adult↗
PubMedDate not supplied

Esophageal tuberculosis. Endoscopic cytology as a diagnostic tool.

OBJECTIVE: To study the utility of endoscopic cytology in the diagnosis of esophageal tuberculosis in clinically unsuspected cases. STUDY DESIGN: During a period of four years, endoscopic cytology of esophageal lesions was performed on 228 patients. In eight (3.5%) the cytologic diagnosis of esophageal tuberculosis was suggested on smears. Upon endoscopic examination, the sites of involvement were mid esophagus (five cases), upper esophagus (two cases) and lower esophagus (one case). Linear ulcer was seen in six cases; growth and narrowing of the lumen were seen in one case each. Endoscopic brush smears in seven cases and fine needle aspiration cytology smear in one case were collected. Air-dried smears stained by Giemsa stain were reviewed for detailed cytologic assessment. RESULTS: Smears showed well-defined granulomas with necrosis in five cases and granulomas without necrosis in three. Cytologic evidence of concurrent poorly differentiated squamous cell carcinoma was observed in one case. Tubercle bacilli were demonstrated in five cases. Endoscopic biopsy showed granulomas in three cases and tubercle bacilli in one case. In six cases there was no clinical or radiologic evidence of tuberculosis at other sites, thereby suggesting the possibility of primary esophageal tuberculosis. The remaining two cases had a past history of tuberculosis; one presented with cervical lymphadenopathy and one mediastinal lymphadenopathy. All patients received antitubercular treatment, and the patient with concurrent malignancy also received radiotherapy. All but one of the patients who succumbed to aspiration pneumonia responded to treatment. CONCLUSION: Endoscopic cytology is a useful modality in the diagnosis of esophageal tuberculosis in clinically unsuspected cases.

Adolescent↗
PubMedDate not supplied

Effect of omeprazole on the pharmacokinetics of sustained-release carbamazepine in healthy male volunteers.

The present study shows the effect of omeprazole administration on the pharmacokinetics of a sustained-release preparation of carbamazepine in healthy male volunteers. Multiple dose administration of omeprazole increased the Cmax, AUC0-infinity and elimination half life (t1/2e) of carbamazepine. The results suggest that drug monitoring should be carried out when carbamazepine is coadministered with omeprazole.

Adult↗
PubMedDate not supplied

Duodenal villous adenoma.

Duodenal villous adenomas are extremely rare (1/5th of small bowel tumors). In view of their strategic position and risk of malignancy, they require definitive management in specialized care units. We report a case of a 35 year old female patient with a large duodenal (5 cm) villous adenoma causing intussusception of duodenum (a phenomenon rare because of its anatomic location & fixation).

Adenoma, Villous↗
PubMedDate not supplied

The antigonadotropic action of testosterone but not 7alpha-methyl-19-nortestosterone is attenuated through the 5alpha-reductase pathway in the castrated male rat pituitary gland.

The enzyme 5alpha-reductase plays a significant role in the prostate to amplify the action of testosterone (T) by converting it to a more potent androgen, dihydrotestosterone (DHT). The role of 5alpha-reductase in the testosterone feedback inhibition of gonadotropin secretion from the pituitary has not been elucidated. Therefore, we investigated the role of 5alpha-reductase on T action in in vitro and in vivo models. Castration has been reported to increase the 5alpha-reductase activity in pituitary glands. Hence, the effect of castration duration on the conversion of T to DHT by pituitary homogenates and the responsiveness of pituitary monolayer cell cultures to gonadotropin-releasing hormone (GnRH) challenge exposure were investigated. Incubation of [3H]-T with pituitary homogenates showed that the conversion of T to 5alpha-reduced metabolites was two- to threefold greater in pituitaries from rats who had been castrated for 14 days compared with those castrated for 1 day. In addition, the GnRH-stimulated release of LH from monolayer cell cultures of pituitaries from rats castrated for 1 day was twofold greater, whereas that from rats castrated for 2 weeks was six- to sevenfold greater compared with basal luteinizing hormone (LH) release. Hence we used rats castrated for 2 weeks to elucidate the role of 5alpha-reductase in T feedback inhibition. The inhibitory effects of the androgens T, 19-nortestosterone (19-NT), and 7alpha-methyl-19-nortestosterone (MENT) at 3 different concentrations (10(-9), 10(-7), and 10(-5) mol/L) on GnRH-stimulated LH release from monolayer cell cultures of pituitaries from rats castrated for 2 weeks were examined. All 3 androgens showed dose-dependent inhibition of LH release. MENT showed the greatest inhibition, followed by 19-NT and T. In the presence of finasteride (a 5alpha-reductase inhibitor), the inhibition of LH released by T and 19-NT were significantly greater. The inhibitory effect of MENT, which does not undergo 5alpha-reduction, was not altered by finasteride. In an in vivo study, rats castrated for 2 weeks received T with or without finasteride. There was a significantly greater suppression of serum LH in rats receiving T plus finasteride compared with those receiving T alone. These results suggested that 5alpha-reductase in the pituitary is not obligatory for the inhibitory action of T on gonadotropin secretion in the castrated rat. The action of MENT, a nonreducible androgen, on the pituitary is not affected by 5alpha-reductase.

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