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Biomedical subjects

K Singh

Publications and source records attributed to K Singh.

At least 145 records · Page 8Linked to original sources
PubMed2000

Gynaecology in the new millennium.

Great challenges await the gynaecologist in the 21st century. While advances in medical technology necessitate that gynaecology move more towards a medical discipline than a surgical one, gynaecologists will be expected to play an increasingly important role in the modern woman's life. This fundamental change is influenced by four main factors, namely, the world's aging population, spread of information technology, advances in molecular based medical therapy, and the changing lifestyle of the woman in the next century. Our role cannot get any lesser as we continue to advise, educate and facilitate the lives of women, and we must aspire a new generation of responsible gynaecologists to continue this ambition.

Aging↗
PubMed2000

Diagnostic value of push-type enteroscopy: a report from India.

OBJECTIVE: We sought to assess the diagnostic value of push-type enteroscopy in relation to indications. METHODS: Ninety-nine consecutive patients (mean age, 42+/-15 yr; 65 men) with suspected small bowel disorders underwent push enteroscopy. The indications were chronic diarrhea (n = 54), obscure gastrointestinal (GI) bleeding (n = 21), abdominal pain (n = 10), abnormal radiological studies of small bowel (n = 5), iron deficiency anemia (n = 5), and others (n = 4). Push enteroscopy was performed using the Olympus SIF-10 (160-cm) enteroscope. RESULTS: Endoscopic examination of the jejunum was successful in all the patients, except one with a distal duodenal stricture. The length of the jejunum examined ranged from 10 to 70 cm. The time taken to complete the procedure varied from 2 to 30 min. Lesions were found in nine (42.8%) patients with obscure GI bleeding; six (28.5%) had worms (Ascaris lumbricoides [n = 3], Ankylostoma duodenale [n = 3]) in the jejunum, producing multiple erosions and bleeding points. In the chronic diarrhea group, a diagnosis was made in 13 (24%) patients on enteroscopic visualization and jejunal histology: celiac disease (n = 6), tropical sprue (n = 3), Crohn's disease (n = 1), secondary lymphangiectasia (n = 1), strongyloidiasis (n = 1), and nodular lymphoid hyperplasia with giardiasis (n = 1). In patients with abdominal pain, enteroscopy provided a diagnosis in one (10%) patient. No positive diagnosis could be made on enteroscopy in patients with iron deficiency anemia and abnormal radiological studies of small bowel. CONCLUSION: Push-type enteroscopy is a useful test in the evaluation of patients with obscure GI bleeding and chronic diarrhea. In developing countries, in patients with obscure GI bleeding, the presence of worms in the jejunum is an important finding on enteroscopy. Tropical sprue, giardiasis, and strongyloidiasis are distinct findings in patients with chronic diarrhea in the present series.

Adult↗
PubMed2000

Partial characterization of a 36-kDa antigen of Entamoeba histolytica and its recognition by sera from patients with amoebiasis.

A 36-kDa antigen of axenically grown pathogenic Entamoeba histolytica (HM1-IMSS) was eluted from the sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE)-resolved crude amoebic extract antigens. The immunoreactivity of this partially purified 36-kDa antigen with monoclonal antibody (MoAb) 3D(10) altered significantly (P<0.01) after heat and trypsin treatment but remained unaltered after treatment with sodium metaperiodate (P0.5), thereby indicating the protein nature of the epitope recognized by MoAb 3D(10). The epitope was found to be localized on the surface as well as in the cytoplasm of the E. histolytica trophozoites with the majority of it in the cytoplasm. In addition, this epitope was also found to be present on the cyst form of the parasite. The 36-kDa molecule was recognized by the sera from 29 (85%) of the 34 patients with amoebic liver abscess and five (83%) of the six patients with amoebic colitis. No serum samples from asymptomatic cyst passers, from patients with non-amoebic hepatic or intestinal disorders and apparently healthy subjects had antibodies that reacted with this 36-kDa molecule. The immune responses in man to this 36-kDa amoebic molecule indicate a potential specific role for this molecule in invasive amoebiasis.

Adult↗
PubMed2000

Influence of soybean trypsin inhibitor on small bowel enzyme activities during rotavirus infection in malnourished infant mice.

Rotavirus (RV) is considered to be one of the major causes of acute episodic diarrhoea throughout the world. This study was undertaken to investigate the effect of soybean trypsin inhibitor (TI) on brush-border enzymes during rotavirus infection in protein energy malnourished (PEM) infant mice. Animals were divided into 4 groups, namely controls, PEM, PEM+RV and PEM+RV+TI (n = 36 each). Group 1 and 2 animals were orally inoculated with 50 microl of normal saline each. Group 3 animals were orally inoculated with 50 microl of 100 ID50 dose of RV stock each. Group 4 animals were similarly inoculated with 0.6 mg TI/g body weight along with 50 microl of RV stock each. Animals were examined daily for diarrhoea and their body weight was recorded on alternate days postinoculation (dpi). Animals were killed by cervical dislocation after being given light chloroform anesthesia on 0, 1, 3, 5, 7 and 10 dpi. Small intestines were excised and homogenized in normal saline. Proteins, gammaglutamyl transpeptidase, alkaline phosphatase and disaccharidases were estimated in jejunum and ileum. Body weight was significantly reduced in PEM animals and with RV infection. Histologically, focal areas of vacuolar degeneration of lining epithelium were seen in RV-infected animals. Disaccharidases and other enzyme activities were decreased significantly in the PEM group compared to healthy controls and further depressed with RV infection in malnourished animals as compared to non-infected PEM. The enzyme activities were restored in animals receiving TI along with RV compared to the group receiving RV without TI. With the administration of soybean TI, the activities of disaccharidases, alkaline phosphatase, gammaglutamyl transpeptidase and intestinal architecture were restored showing a protective effect in PEM during RV infection.

Animals↗
PubMed2000

Isoniazid- and rifampicin-induced oxidative hepatic injury--protection by N-acetylcysteine.

The role of N-acetylcysteine (NAC), a glutathione (GSH) precursor, was investigated in protection against isoniazid- (INH) and rifampicin- (RIF) induced oxidative hepatic injury in young Wistar rats. The hepatotoxic dose of INH and RIF was 50 mg kg(-1) day(-1) each and the hepatoprotective dose of NAC was 100 mg kg(-1) day(-1). All drugs were administered intraperitoneally (i.p.) in sterile water (4.0 ml kg(-1) day(-1)) over a period of 3 weeks. Status of oxidative/antioxidative profiles was the mechanistic approach to assess the hepatotoxicity and/or hepatoprotection. The oxidative injury in INH-RIF co-exposed animals was closely associated with significant decline of GSH and related thiols, as well as with compromised antioxidant enzyme system. The oxidative stress was further supported by increased lipid peroxidation observed in these animals. The co-administration of NAC prevented the induction of oxidative stress in INH-RIF co-exposed animals. The amelioration of oxidative stress by NAC was faithfully reflected as normal morphology in these animals, except the presence of mild degree of portal triaditis in one animal co-exposed to INH-RIF and NAC. In contrast, the animals co-exposed to INH-RIF alone showed histological lesions which ranged from intralobular inflammation to patchy necrosis. These results suggest that INH-RIF-induced oxidative injury can be prevented by supporting the cellular antioxidant defense mechanism by NAC.

Acetylcysteine↗
PubMed2000

The subspecialty training, practice type, and geographical distribution of recently trained ophthalmologists: a study of male and female physicians.

OBJECTIVE: To characterize the distribution of male and female ophthalmologists with regard to practice type, subspecialty training, rural-urban distribution, and regional distribution. METHODS: Ophthalmology Matching Program files containing the records of residents who began their second year at accredited programs between 1986 and 1990 (inclusive), were compared to membership files of the American Academy of Ophthalmology. Practice locations for each individual were classified according to region, stage, and Rural-Urban Continuum County Code, as defined by the US Department of Agriculture. RESULTS: This cohort comprised 2,494 individuals, 77.1% (1922) of whom were male and 22.9% (572) of whom were female. Group practice was most common (55.9% for women and 61.3% for men). More women were in salaried positions associated with health maintenance organizations (p = 0.006) and academic settings (p < 0.001) than were men. Notable differences in subspecialty choice were restricted to pediatric ophthalmology, chosen three times more frequently by women, and vitreoretinal diseases/surgery, chosen twice as often by men. Only 5.6% of women selected nonmetropolitan practice locales compared to approximately twice that percentage of men. The Middle Atlantic and New England regions attracted more women, while the South Atlantic attracted more men.

Cohort Studies↗
PubMed2000

Seasonal adiposity and androstenedione production as a possible mechanism for asynchronous reproductive activity between males and females of vespertilionid bat, Scotophilus heathi.

Relationship between changes in the body weight and circulating androstenedione concentration was examined in order to find out their involvement in asynchronous gametic cycle of male and female S. heathi. Body weight of both male and female bats increased from September due to accumulation of white adipose tissue and reached to a peak in November. The body weight declined gradually due to consumption of adipose tissue during December and January reaching basal level in February. A significant correlation between body weight and serum androstenedione concentration was observed. Correlated with maximum body weight, peak androstenedione level was found during November in both male and female bats. Peak androstenedione level during November may be responsible for stimulating spermatogenesis in the male, but may suppress follicular growth and ovulation in the female, thus resulting in asynchronous gametic cycle of male and female S. heathi.

Adipose Tissue↗
PubMed2000

Adrenergic overload and apoptosis in heart failure: implications for therapy.

Sympathetic nervous system activity to the myocardium is increased in patients with heart failure. It is now appreciated that norepinephrine (NE), the primary sympathetic neurotransmitter, can exert direct adverse effects on cardiac myocytes and might thereby contribute to pathological remodeling, a chronic process which leads to progressive left ventricular (LV) chamber dilation and loss of contractile function. The demonstration of apoptosis in failing human hearts has led to the thesis that continuing loss of viable myocytes is a mechanism for progressive myocardial failure. For many years it has been appreciated that chronic exposure to catecholamines can exert a toxic effect on the myocardium. In vitro studies in cultured cardiac myocytes show that tonic exposure to NE increases the number of apoptotic myocytes via stimulation of the beta-adrenergic receptor (beta-AR) pathway. Interestingly, a beta1-AR selective antagonist completely prevented NE-stimulated apoptosis, whereas a beta2-AR selective antagonist increased the amount of apoptosis, suggesting that beta1- versus beta2-AR may couple to different signaling pathways. In rats, isoproterenol infusion for as little as 12 hours increased the frequency of terminal deoxynucleotidyltransferase-mediated nick end-labeling (TUNEL)-positive myocytes. Likewise, mice that overexpress beta1-AR or G alpha s in the myocardium develop left ventricular dilation, contractile dysfunction and apoptosis. Although the link between apoptosis and myocardial failure remains to be proven, these in vitro and in vivo observations provide a rational mechanism by which beta-AR antagonists may help to prevent or slow LV remodeling and failure in patients.

Adrenergic beta-Agonists↗
PubMed2000

Immunohistochemical localization and correlation of p53 and PCNA expression in breast carcinoma.

The object of the present study is to detect the p53 tumour suppressor gene and proliferation cell nuclear antigen (PCNA) expression in breast carcinoma by immunohistochemistry and correlate them with the prognostic parameters. Total 35 cases of primary breast carcinoma were studied and classified histologically. Paraffin sections were stained by using monoclonal antibody D07 for p53 protein and PC-10 for PCNA. Out of 35 cases, 16 (45.7%) were p53 positive and 25 (71.4%) were PCNA positive. The mean PCNA labelling index (PCNA LI +/- SD) was 58.97 +/- 22.72 in tumors positive for both p53+ and PCNA+ while cases negative for p53- and positive for PCNA+ has higher PCNA LI +/- SD (59.24 +/- 18.97). The difference in the two groups was not significant. Most cases were positive for both p53+ and PCNA+ in the age group < 30 with higher mean PCNA LI +/- SD (62.20 +/- 27.13) than in the group > 30 (57.88 +/- 18.47). In the pre-menopausal group 57.1% cases were positive for p53+ with higher PCNA LI +/- SD (59.94 +/- 24.22). Maximum p53 and PCNA positivity was observed in grade III tumors (63.2% and 84.2%). The mean PCNA LI +/- SD was also highest in grade III carcinomas (66.83 +/- 13.97). No significant correlation was found between p53 and PCNA status with morphological type and tumour size except that logistic regression showed a positive correlation with tumour grade. Therefore the present study suggests that both p53 expression and PCNA are markers of poor differentiation in breast cancer.

Adult↗
PubMed2000

Recruitment properties of intramuscular and nerve-trunk stimulating electrodes.

Functionally useful reanimation of paralyzed limbs generally requires reliable, finely graded control of muscle recruitment and force with minimal fatigue. We used force and electromyographic (EMG) recordings in combination with myofibrillar adenosine triphosphatase activity and glycogen depletion analysis to investigate the recruitment properties of intramuscular (IM) and nerve cuff (NC) stimulating electrodes implanted acutely or chronically in cat hindlimbs. Overall, 32 muscles were submaximally stimulated with current intensities producing approximately 20% of maximal twitch force using 330 ms trains of pulses at 20 and 40 pps. Both the glycogen-depletion and fatigue-test results were found to be difficult to interpret because NC stimulation resulted in surprisingly unstable recruitment during such trains. Fluctuations of force and M-waves within trains of identical stimuli were significantly greater for NC than for IM stimulation. NC stimulation produced much steeper recruitment curves and a reduced tetanus/twitch ratio compared to IM stimulation. IM stimulation produced more reliable and less fatigable recruitment of a mix of motor unit types that tended to be localized in neuromuscular compartments containing, or adjacent to, the IM electrode. We hypothesize that trains of submaximal stimulation applied through NC electrodes resulted in fluctuating recruitment because this electrode configuration magnifies the effects of refractoriness and small changes in axonal excitability during pulse trains.

Acute Disease↗
PubMed2000

Epidemic dropsy--a clinical study of the Delhi outbreak.

BACKGROUND: A major outbreak of epidemic dropsy occurred in Delhi, India, in August-September 1998, due to the consumption of contaminated mustard oil. METHODS: The clinical data of 212 adult patients of epidemic dropsy who presented to our hospital is analysed. RESULTS: Pitting pedal oedema (100%), skin erythema (75%), limb tenderness (63%), diarrhea (51%) and hepatomegaly (34%) were the prominent clinical manifestations observed in the patients. Superficial retinal haemorrhages and retinal venous dilatation was observed on fundus examination and 9% of patients developed an open angle glaucoma over a three month follow up period. Cardiac failure was present in 14% of patients. Most patients had mild disease which responded to cessation of mustard oil consumption, bed rest, diuretics and antioxidants. There were six deaths, all of whom had intractable cardiac failure. A unique feature of this outbreak was the documentation of acute renal failure in three patients, a phenomenon never described previously. CONCLUSIONS: Strict law enforcement to prevent the contamination of edible oils is essential to avoid the occurrence of future similar outbreaks.

Adolescent↗
PubMed2000

Effect of alcohol dependence on the levels of duodenal disaccharidases in human subjects.

BACKGROUND: The aim of the study was to detect the duodenal enzyme activity in patients of alcohol dependence and to compare with non-alcoholic patients of non-ulcer dyspepsia. METHODS: Disaccharidases (lactase, sucrase, maltase) were estimated in 20 non alcoholic patients of non-ulcer dyspepsia and 20 alcoholics admitted to the drug de-addiction and treatment centre of PGIMER, Chandigarh, India. RESULTS: No significant influence of alcohol on enzyme levels in patients of alcohol dependence when compared to patients of non-ulcer dyspepsia was observed. However, a significant decrease in lactase level was noted in patients consuming more than 125 gm/day of alcohol. CONCLUSION: Amount of consumption of alcohol showed decrease in lactase enzyme, but not in maltase and sucrase. There was no effect of duration of alcohol consumption on dissacharidases in the two groups.

Adult↗
PubMed2000

Rotavirus infections.

In 1976, John Rohde, highlighting the importance of diarrhea as prime killer of children in the developing world, beckoned the scientific community to "take science where the diarrhea is". The World Health Organization estimates that one billion diarrheal episodes occur in infants annually resulting in 3.3 million deaths, making diarrheal disease a major contributor to infant mortality in developing world (Bern et al., 1992). The need for simple, effective and inexpensive intervention to treat diarrhea and to prevent its occurrence is urgent and abundantly clear. Among the etiological agents of acute infectious diarrhea rotaviruses account for nearly 25% of hospital admissions in India with vomitting and diarrhea followed by severe dehydration in very young children below 2 years of age (Broor et al., 1985). In developing countries, it has been estimated that more than 870,000 children die from rotavirus infection every year (Perez-Schael, 1996). The discovery of rotavirus by Bishop and colleagues in 1973 initiated a line of research that has progressed rapidly towards the goal of prevention of rotavirus diarrhea (Bishop et al., 1973).

Clinical Trials as Topic↗
PubMed2000

Immunohistochemical localization of transferrin in human breast cancer tissue.

The present study was planned to detect the iron binding protein, transferrin (TR) in paraffin sections of the human breast tumors. The distribution of transferrin has been studied in 153 cases (63 benign lesions and 90 malignant tumors). The extent of staining reaction was determined by semiquantitative grading (weak, moderate and consistent). Positivity rate for transferrin was higher (92.2%) in malignant tumors as compared to benign breast lesions (28.5%) with significant p value (p = 0.0001) for both the groups. The intensity was variable in both the groups, being more intense in the malignant tumors. Tumors with higher grade of malignancy presented consistent positive staining along with the lymph nodes involved. The extent of immunoreactivity revealed a significant positive correlation with axillary lymph node status. However, no significant correlation was found with the age of the patients. Thus the study of transferrin in breast tumors besides being of prognostic significance helps in the further management of malignant lesions of the breast.

Breast↗
PubMed1999

Opposing effects of beta(1)- and beta(2)-adrenergic receptors on cardiac myocyte apoptosis : role of a pertussis toxin-sensitive G protein.

BACKGROUND: beta-Adrenergic receptor (beta-AR) stimulation increases apoptosis in adult rat cardiac (ventricular) myocytes (ARVMs) via activation of adenylyl cyclase. beta(2)-ARs may couple to a G(i)-mediated signaling pathway that can oppose the actions of adenylyl cyclase. METHODS AND RESULTS: In ARVMs, beta-AR stimulation for 24 hours increased the number of apoptotic cells as measured by flow cytometry. beta-AR-stimulated apoptosis was abolished by the beta(1)-AR-selective antagonist CGP 20712A (P<0.05 versus beta-AR stimulation alone) but was potentiated by the beta(2)-AR-selective antagonist ICI 118,551 (P<0.05 versus beta-AR stimulation alone). The muscarinic agonist carbachol also prevented beta-AR-stimulated apoptosis (P<0.05 versus beta-AR stimulation alone), whereas pertussis toxin potentiated the apoptotic action of beta-AR stimulation (P<0.05 versus beta-AR stimulation alone) and prevented the antiapoptotic action of carbachol. CONCLUSIONS: In ARVMs, stimulation of beta(1)-ARs increases apoptosis via a cAMP-dependent mechanism, whereas stimulation of beta(2)-ARs inhibits apoptosis via a G(i)-coupled pathway. These findings have implications for the pathophysiology and treatment of myocardial failure.

Adenylate Cyclase Toxin↗