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Biomedical subjects

G Singh

Publications and source records attributed to G Singh.

At least 397 records · Page 22Linked to original sources
PubMed1994

Combined bladder neck suspension and augmentation cystoplasty for neuropathic incontinence in female patients.

OBJECTIVE: To perform bladder neck suspension simultaneously with augmentation cystoplasty in female patients where sphincteric incompetence was not the sole cause of impaired functional bladder capacity. PATIENTS AND METHODS: During an 8-year-period, 26 female patients (mean age 14, range 5-39) were treated with a Marshall-Marchetti plus cystoplasty (Liverpool) or a colposuspension plus clam cystoplasty (Sheffield). All had marked sphincteric incompetence compounded by detrusor hyper-reflexia and/or non-compliance. The patients were followed up for a mean period of 30 months (range 8-80). RESULTS: There were no major complications. At follow-up 23 (88%) were dry by day on a regime of intermittent self-catheterization. Nine patients were taking adjuvant medication, usually for prevention of nocturnal enuresis. CONCLUSION: The results compare tolerably with those of all alternative procedures, including the more elaborate reconstructions (e.g. Kropp procedure) and the expensive artificial urinary sphincter.

Adolescent↗
PubMed1994

Altered endothelin 1 concentration in brain and peripheral regions during thyroid dysfunction.

Earlier studies have shown that plasma concentrations of endothelin 1 (ET-1) and the receptors for ET are altered during hyperthyroidism, while they are not affected during hypothyroidism. The present study was undertaken to determine the changes in concentration of endogenous ET-1 in various tissues of hyper- and hypothyroid rats. Hyperthyroidism was induced by daily administration of thyroxine (T4, 0.1 mg/kg, i.p.) for 8 weeks, while hypothyroidism was induced by daily administration of methimazole (10 mg/kg, i.p.) for 8 weeks. The concentration of endogenous ET-1 was determined in the brain regions (hypothalamus, corpus striatum, pituitary, hippocampus and spinal cord), heart, adrenals, kidneys and thoracic aorta using a radioimmunoassay procedure. Blood pressure and heart rate were significantly increased in hyperthyroid rats, while they were not affected in hypothyroid rats when compared with control (euthyroid) rats. Serum T4 and T3 levels were significantly increased in hyperthyroid rats, while they were significantly decreased in hypothyroid rats when compared with euthyroid rats. The concentrations of ET-1 in the hypothalamus, corpus striatum, hippocampus and spinal cord were not altered in hyper- or hypothyroid rats when compared with euthyroid rats. However, the pituitary showed a significant (p < 0.001) increase (104%) in ET-1 concentration in hyperthyroid rats when compared with euthyroid ones, while hypothyroid rats did not show any significant change in ET-1 concentration in the pituitary. In peripheral tissues ET-1 concentrations were not altered in the heart and adrenals of hyper- and hypothyroid rats when compared with euthyroid rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Glands↗
PubMed1994

Clinical significance of heparin in the residual pump oxygenator blood, reinfused postoperatively after cardiopulmonary bypass.

Postcardiopulmonary bypass (CPB) heparin levels and thrombin time were measured in 20 patients following routine open cardiac operations. There was a statistically significant increase in heparin concentration and thrombin time ratio on completion of transfusion of the residual pump oxygenator blood. An hour after the end of the transfusion there was no statistically significant difference in the heparin concentration and thrombin time ratio compared to values before and immediately after transfusion. We also observed a significant decrease in the chest drainage over a period of four hours which was unrelated to plasma heparin level. Measurements of thrombin time in the post bypass period closely follow plasma heparin levels. If postoperative bleeding arose it was due to inadequate surgical haemostasis or coagulation defect other than residual heparinization. Thus this confirms further that heparin is not the sole aetiological factor in postoperative bleeding post-CPB.

Adult↗
PubMed1994

Plutonium-induced proliferative lesions and pulmonary epithelial neoplasms in the rat: immunohistochemical and ultrastructural evidence for their origin from type II pneumocytes.

Immunohistochemistry and transmission electron microscopy were used to clarify the cellular origin for plutonium-239-induced pulmonary proliferative (preneoplastic) epithelial lesions and epithelial neoplasms in F344 rats. Examples of each histologic type of proliferative lesion and neoplasm were stained by the avidin-biotin complex immunoperoxidase method using antibodies to rat surfactant apoprotein and Clara cell antigen. Rat surfactant apoprotein immunostaining was detected in type II pneumocytes in sections of normal lung, in the cells of the proliferative lesions classified histologically as alveolar epithelial hyperplasia (51) and mixed foci (alveolar epithelial hyperplasia with fibrosis) (30), and in adenomas (2), adenocarcinomas (3), and adenosquamous carcinomas (2). With the exception of one adenosquamous carcinoma, Clara cell antigen immunostaining was not detected in any of the pulmonary lesions but was detected in nonciliated cuboidal epithelial (Clara) cells in normal bronchioles. The epithelial cells of the proliferative lesions and neoplasms had ultrastructural features consistent with type II pneumocytes, i.e., the presence of cytoplasmic lamellar and multivesicular bodies. The results of these studies indicate that the majority of plutonium-induced proliferative epithelial lesions and neoplasms in the rat originate from alveolar type II pneumocytes.

Animals↗
PubMed1994

Malignant hypertension in north west India. A hospital based study.

One hundred and thirty-five patients with malignant hypertension seen over a period of 11 years (1979 to 1989) at a referral hospital were analyzed to characterize the clinical features and etiology of this disease. Ninety male and 45 female patients with an average age of 38.2 +/- 1.4 years were studied. Malignant hypertension was the presenting feature in 68 patients. The etiology included essential hypertension in 88 patients and a secondary cause in 47 patients. Secondary causes included a renovascular etiology in 20 patients, renal parenchymal disease in 19, pheochromocytoma in 6 and Conn's syndrome and adrenal carcinoma in one patient each. Among the 20 patients with renovascular hypertension, Takayasu's arteritis was seen in 15 (75%). The mean age of patients with essential hypertension was 41.7 + 1.14 years while the mean age in patients with secondary hypertension was 33.2 + 1.96 years. Duration of preexisting hypertension was longer in essential hypertensives (2.42 + 0.45 years) than in patients with secondary hypertension (1.27 + 0.41 years, p < 0.05). Raised serum creatinine was seen in 93 patients. Seventy-seven patients had left ventricular hypertrophy on ECG. Ninety-six patients were followed for a period ranging from 18 months to 10 years (mean 32 months). Sixteen patients died during hospital stay while 6 patients died during the follow-up period. The deaths were related to the effects of uncontrolled hypertension including, renal failure (11), stroke (6), congestive cardiac failure (3) and myocardial infarction (1).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

Phacolytic glaucoma--its treatment by planned extracapsular cataract extraction with posterior chamber intraocular lens implantation.

Phacolytic glaucoma has traditionally been treated with intracapsular lens extraction to avoid any anaphylaxis. Various mechanisms have been described for the rise of intraocular pressure in these cases. The present study was undertaken to evaluate the response of extracapsular cataract extraction (ECCE) with posterior chamber intraocular lens implantation (PC IOL) in five cases of phacolytic glaucoma that occurred between March 1989 and August 1990. A planned extracapsular cataract extraction with can-opener capsulectomy was done in all the cases with placement of a sulcus-fixated modified J-loop Sinskey design intraocular lens. With a mean follow-up period of two years, all patients (100%) maintained a normal postoperative intraocular pressure of less than 20 mm Hg without any additional medical therapy. The final best-corrected visual acuity in 4 cases (80%) was 6/12 or better, while in one case it was 6/24 due to a senile maculopathy. These results show that ECCE with PC IOL implantation is a safe and efficacious method of visual rehabilitation in cases of phacolytic glaucoma.

Aged↗
PubMed1994

Characterization of A/eq-1 virus isolated during the equine influenza epidemic in India.

The equine influenza virus, Ludhiana/5/87, isolated from the clinical material during the epidemic of equine influenza in India in 1987 was inhibited in haemagglutination-inhibition test by the antiserum against the prototype A/eq/Prague/1/56 (H7N7) virus and by post-epidemic horse sera. In haemagglutinin and neuraminidase analysis, the A/eq/Ludhiana/5/87 isolate appeared similar to the prototype A/eq/Prague/1/56 virus and was characterized as the H7N7 subtype.

Animals↗
PubMed1993

Immunohistochemistry of a human type I pneumocyte-associated protein in lung.

A mouse monoclonal antibody to a human lung lavage protein was raised using proteins, with the potential ability to bind surfactant, as the immunogen. The proteins were isolated from cadaver lung lavage. The antibody was tested for its reactivity with lung and other organs. It reacted with type I pneumocytes and some of the nonciliated cells in the surface epithelium of distal bronchioles. Staining was also seen in the cells surrounding the glandular structures, superficial keratinocytes of the skin, endothelium, and nerve sheath cells. With the exception of bronchiolar cells, the stained cells have a squamous morphology, and this protein may serve as a marker or determinant of this characteristic of cells. In pathologic lungs some of the cells in air spaces with "bronchiolarization" of the epithelium exhibited staining for the protein. It could not be ascertained whether the stained cuboidal cells were reactive type II pneumocytes or distal bronchiolar cells. The intraalveolar material in pulmonary alveolar proteinosis did not show remarkable staining for the protein. Even though the protein is not unique to type I pneumocytes, it may serve as a marker for these cells in the study of their development and biology.

Animals↗
PubMed1993

N-(1-arylpropionyl)-4-aryltetrahydropyridines, a new class of high-affinity selective sigma receptor ligands.

A series of N-(1-arylpropionyl)-4-aryl-1,2,3,6-tetrahydropyridines, prepared by simple Mannich condensations, have been found by radioligand binding assays to have moderate to high affinity (IC50 0.5-500 nM) for bovine cerebellar sigma receptor/binding sites and no measurable affinity (IC50 > 5000 nM) for bovine striatal D2 receptors. The most active of these compounds rival in potency the most active sigma ligands previously reported. Three of these sigma-active compounds were screened for pharmacological activity under the NIMH-NovaScreen program and showed moderate affinity only for D2 and 5-HT2 receptors among the 40 sites assayed. Since these N-(1-arylpropionyl)-4-aryltetrahydropyridines are structurally related to other potent sigma receptor ligands, in particular haloperidol and 4-phenylpiperidines, these data provide insights into the nature of the essential pharmacophore of the sigma receptor. The selective affinity of these materials for sigma receptors indicates they have potential as prototypes of novel psychotherapeutic medicinal agents, particularly as antipsychotic drugs which would be devoid of debilitating side effects associated with blockade of D2 receptors.

Animals↗
PubMed1993

Increased growth rate and tumor burden of spontaneously metastatic Walker 256 cancer cells in the skeleton of bisphosphonate-treated rats.

We have studied the effect of 3-amino-1-hydroxypropylidene-1,1-bisphosphonate (APD) on the morphology of rat bone and the metastatic behavior of Walker 256 (W256) cancer cells in the rat skeleton. Male Fischer rats (150-175 g) received s.c. injections for 7 days with APD (0.5 mg/kg body weight/day) (+ APD; n = 20) or with vehicle (-APD; n = 20). Subsequently, 10 + PD and 10 -APD rats received i.m. injections with W256 cells (+ W256), and the remaining rats received injections of vehicle (-W256). All rats were killed 14 days later. Trabecular bone volume was increased by 46 +/- 3% by APD treatment alone and was decreased by 56 +/- 7% (SEM) by W256 tumor burden alone. After 14 days of tumor burden, + APD/+ W256 rats had 3-fold more trabecular bone than did -APD/+W256 rats. Despite this bone-sparing effect, APD treatment of +W256 rats was associated with a 2.6-fold increase in skeletal tumor burden, while metastatic tumor burden in the liver, lungs, and kidneys was unaffected. The increased skeletal tumor burden in + APD/+ W256 rats was accompanied by an increase in the growth rate of W256 cells located in bone. Independent of APD treatment, W256 cells located adjacent to trabecular bone surfaces had greater growth rates than did W256 cells in the marrow, located > 50 microns from trabecular bone. In summary, the APD-induced increase in trabecular bone volume in rats is associated with a selective increase in skeletal tumor burden and an increased growth rate of W256 cells in the skeleton.

Acid Phosphatase↗
PubMed1993

A reevaluation of aspirin therapy in rheumatoid arthritis.

BACKGROUND: Aspirin therapy has been largely superseded by prescription nonsteroidal anti-inflammatory drug (NSAID) therapy in rheumatoid arthritis, in part because of premarketing studies suggesting lesser toxic effects for NSAIDs than for aspirin. This study evaluates these toxic effects in a postmarketing population of patients with rheumatoid arthritis. METHODS: We studied 1521 consecutive courses of aspirin and 4860 courses of NSAIDs in patients with rheumatoid arthritis from eight Arthritis, Rheumatism, and Aging Medical Information System Post-marketing Surveillance Centers. Toxicity index scores were generated from symptoms, laboratory abnormalities, and hospitalizations, weighted for variable severity and severity of side effect. RESULTS: The toxicity index was only 1.37 (SE = 0.10) for aspirin and 1.87 to 2.90 for selected nonsalicylate NSAIDs. These differences were consistent across centers and remained after statistical adjustment for differing patient characteristics. There was a different toxicity with different aspirin preparations, with a score for plain aspirin of 1.36 (SE = 0.23), for buffered aspirin of 1.10 (0.20), and for enteric-coated aspirin preparations of 0.92 (0.14). Most important, there were strong dose effects, with a score of 0.73 (0.09) for 651 to 2600 mg daily, 1.08 (0.17) for 2601 to 3900 mg, and 1.91 (0.38) for more than 3900 mg. The average aspirin dose taken was only 2665 mg/d, approximately eight "tablets," compared with 3600 to 4800 mg/d used in the 16 pivotal premarketing studies reviewed. Average NSAID doses were, on the other hand, lower in premarketing trials (eg, naproxen 500 mg/d vs 773 mg/d in the Arthritis, Rheumatism, and Aging Medical System clinical practices). CONCLUSIONS: Aspirin therapy, in doses commonly employed in practice, has an excellent safety profile in rheumatoid arthritis, and it is the least costly NSAID. The safety advantage is explained primarily by a dose effect and secondarily by possible differences between formulations. Newer management strategies for rheumatoid arthritis emphasize NSAID use as symptomatic therapy and use of disease-modifying anti-rheumatic drug therapy for anti-inflammatory objectives. Thus, the original recommendation for "anti-inflammatory" doses of aspirin now is less easily justified. Aspirin therapy merits reconsideration as adjunctive therapy for the management of rheumatoid arthritis.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1993

Mitochondrial alterations in photodynamic therapy-resistant cells.

The characterization of radiation-induced fibrosarcoma cells (RIF-8A) which have been selected for resistance to Photofrin-mediated photodynamic therapy (PDT) is detailed in this report. Morphological and functional assessment of mitochondria in both the resistant RIF-8A and parental RIF-1 cells show distinct differences. Electron micrographs show that the mitochondria in the RIF-8A cells are relatively smaller; stain more densely, and display a higher cristae density than RIF-1 cells. P. A. Andrews et al. (Cancer Res., 52: 1895-1901, 1992) reported similar mitochondrial differences between a human ovarian carcinoma cell line, 2008, and its cisplatin-resistant counterpart (C13*). Dose-response curves demonstrate that these cisplatin-resistant C13* cells show cross-resistance to Photofrin-mediated PDT. Functionally, the RIF-8A cells produce more ATP and demonstrate higher succinate dehydrogenase activity than do the RIF-1 cells, but the rates of oxygen consumption do not differ between the two cell types. The PDT-sensitive RIF-1 cells demonstrate a significantly higher susceptibility to inhibition of glycolytic activity as determined by 2-deoxy-d-glucose survival curves. These findings suggest differences in the efficacy and/or mode(s) of energy production in the RIF-1 and RIF-8A cells. Since mitochondria are sensitive targets for porphyrin-mediated PDT, the observed changes in mitochondrial structure and/or function may be involved in the PDT resistance seen in RIF-8A cells.

Adenosine Triphosphate↗