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Biomedical subjects

P Gulati

Publications and source records attributed to P Gulati.

At least 37 records · Page 2Linked to original sources
PubMed1994

Involvement of nitroxyl (HNO) in the cyanamide-induced vasorelaxation of rabbit aorta.

Relaxation of precontracted rabbit aortic rings in vitro by cyanamide, a clinically used alcohol deterrent drug, required catalase and H2O2, suggesting that a bioactivation mechanism was involved. Since the oxidation of cyanamide by catalase/H2O2 had been shown previously to lead to nitroxyl (HNO) generation via the intermediate N-hydroxycyanamide, and aortic ring relaxation was inhibited by the catalase inhibitor, 3-aminotriazole, HNO appears to be responsible for the vasorelaxation mediated by cyanamide. This was further supported by the observation that N,O-dibenzoyl-N-hydroxycyanamide (DBHC), a derivative of N-hydroxycyanamide that releases HNO in the absence of catalase/H2O2, was a potent vasorelaxant, with an EC50 of 4.2 +/- 1.3 x 10(-6) M.

Animals↗
PubMed1994

Expression of the components and regulatory proteins of the classical pathway of complement in normal and diseased synovium.

We studied the synthesis of the classical pathway complement components in synovial membrane. Ribonucleic acid was extracted from the synovial membranes of patients with rheumatoid arthritis (RA) or osteoarthritis (OA), as well as from normal synovial membrane. Northern blot and dot blot analysis showed that the mRNAs for all classical pathway complement components (C1qA chain, C1qB chain, C1qC chain, C1r, C1s, C4 and C2) and the fluid-phase regulatory components (C1-inhibitor, C4-bp and factor I) were present in all three types of synovial membrane. Thus, all the components of the classical pathway were expressed in normal and diseased synovium. In an attempt to determine which components were synthesised by each cell type, monocytes (mononuclear phagocytes), human umbilical vein endothelial cells (HUVEC), synovial membrane fibroblasts (from normal, OA and RA synovial membrane) and peripheral blood lymphocytes were cultured in vitro and secretion rates of individual components were measured and total cellular RNA was analysed by Northern blotting. Monocytes secreted C1q, C1r, C1s, C4, C2, C1-inhibitor and C4-bp but not factor I. Fibroblasts secreted C1r, C1s, C2, C3, C1-inhibitor and factor I but not C1q, C4 or C4-bp. HUVEC secreted C1s, C2, C1-inhibitor and factor I but not C1q, C1r, C4 or C4-bp. Lymphocytes did not secrete any of these components. In three instances mRNA was detected in the absence of secreted protein: mRNAs for the C1qA and C1qC chains were detected in HUVEC, whereas the mRNA for the C1qB chain was not, and C4 mRNA was detected in both fibroblasts and HUVEC.(ABSTRACT TRUNCATED AT 250 WORDS)

Arthritis, Rheumatoid↗
PubMed1994

MRI (magnetic resonance imaging) spectrum of epilepsy.

In 361 patients with strong clinical suspicion of secondary epilepsy magnetic resonance imaging (MRI) was performed. Three hundred and forty-five patients revealed a positive study. Maximum number of patients (28.3%) were in the age group of 2 to 12 years without any significant sex predilection. More than 70% patients presented with generalised seizures. MRI revealed definite evidence of tuberculoma in 98, neurocysticercosis in 86, tumour in 60 and cerebrovascular accident in 23 patients. There were 78 patients in miscellaneous group which included patients with magnetic resonance (MR) diagnosis of generalised or focal atrophy, demyelinating disease, hydrocephalus with or without basal exudates, calcification and disappearing lesion. In 16 patients MR was found to be within normal limits.

Adolescent↗
PubMed1993

Studies on the leaching of fluoride in tea infusions.

In order to assess the levels of fluoride ingestion through intake of tea, studies were conducted with four different brands of tea leaves commonly available in the Indian market. Four most prevalent methods for the preparation of tea with various contact times (2,4,6,8 and 10 min) of tea leaves with water show that: (a) leaching of fluoride is least in case of leaf tea as compared to powdered tea (F levels increasing with decreasing grain size); (b) leaching of fluoride reaches a maximum after a contact of about 6 min; (c) there is no difference between levels of fluoride with or without addition of milk in the English style where tea leaves are not boiled, while for the Indian style, addition of milk and subsequent boiling resulted in reduction of fluoride levels and (d) ingestion of fluoride per cup of tea ranged from 1.55 mg/l to 3.21 mg/l amounting to an intake per day per person of fluoride between 0.3 to 1.9 mg.

Fluorides↗
PubMed1993

Expression of the components and regulatory proteins of the alternative complement pathway and the membrane attack complex in normal and diseased synovium.

We have studied synthesis of the complement components and regulatory proteins of the alternative pathway and the membrane attack complex in synovial membrane. RNA was extracted from synovial tissue of patients with rheumatoid arthritis (RA) or osteoarthritis (OA) as well as from normal synovial membrane. Dot blot analysis showed the presence of mRNAs for all the complement components and regulatory proteins (C3, factor B, factor D, C5, C6, C7, C9, factor H, factor I, S-protein, SP-40, 40, DAF, MCP, CR1, CD59), except for properdin, C8 alpha, C8 beta and C8 gamma in all three types of synovial membrane studied. In an attempt to determine which components were synthesised by each cell type, monocytes (mononuclear phagocytes), human umbilical vein endothelial cells (HUVEC), synovial membrane fibroblasts (from normal, OA and RA synovial membrane) and peripheral blood lymphocytes were cultured in vitro and secretion rates of individual components were measured and total cellular RNA analysed by northern blotting. Monocytes secreted properdin, C3, and factor H but not factor B, factor I, C5, C6, C7, C8 or C9. Fibroblasts and endothelial cells secreted factor B, factor H and factor I, but not properdin, C5, C6, C7, C8 or C9. Lymphocytes did not secrete any of these components. mRNAs encoding C3, factor B, factor H, S-protein, SP-40, 40, MCP and DAF were detected in all three other cell types (monocytes, fibroblasts and HU-VEC), but factor I and CD59 mRNAs were not detected in monocytes. C5, C6, C7, C8 alpha, C8 beta, CD8 gamma and C9 mRNAs were not detected in any of the cell types studied.(ABSTRACT TRUNCATED AT 250 WORDS)

Arthritis, Rheumatoid↗
PubMed1993

An evaluation of rapid exchange and simultaneous grip tests.

The usefulness of the rapid exchange grip test and a modification of this test, the rapid simultaneous grip test, in detecting submaximal grip efforts was evaluated. Uninjured subjects giving maximal or submaximal grip efforts were tested at grip rates of 80 and 100 repetitions per minute. Rapid exchange grip at 80 repetitions per minute yielded a sensitivity of 86% and a specificity of 97%. Rapid simultaneous grip at 80 repetitions per minute yielded a sensitivity of 81% and a specificity of 93%. Poorer sensitivities and specificities resulted when a clinical population of patients was tested. Patients who were not giving maximal efforts tended not to comply with the test protocol. The rapid exchange and rapid simultaneous grip tests do assist in detecting submaximal grip efforts; limits to these tests are emphasized.

Adolescent↗
PubMed1993

Magnetic resonance imaging of the brain in idiopathic hypogonadotropic hypogonadism.

Magnetic resonance imaging (MRI) of the pituitary, hypothalamus and olfactory sulci was performed in 40 patients with idiopathic hypogonadotropic hypogonadism (IHH). Twelve of these patients had an impaired sense of smell (Kallmann's syndrome). Sagittal and coronal imaging revealed no morphological abnormalities in the hypothalamic-pituitary region. On axial imaging rudimentary, hypoplastic or aplastic olfactory sulci were found in eight cases. All patients with olfactory sulcal abnormalities had associated hyposmia (one case) or anosmia (seven cases). Structural defects identifiable on MRI were present only in 20 per cent of patients with IHH.

Adult↗
PubMed1993

NADPH-diaphorase positive cells in the chick and rat thymus.

Nicotinamide-adenine dinucleotide phosphate-diaphorase (NADPH-d) positive cells were demonstrated in the medulla of the rat and chick thymus at light microscopic level. The NADPH-d positive cells were present as clusters and were predominantly localized near the corticomedullary boundary. These clusters were closely associated with the thymic cysts. Some cells were seen in close proximity to blood vessels. The presence of nitric oxide (NO) as indicated by the positive NADPH-d reaction in the cells forming the wall of the thymic cyst suggests a modulatory influence of NO over the activities of these cells. Other possible functions of NO are also discussed.

Amino Acid Oxidoreductases↗
PubMed1993

Regulation of the synthesis of C1 subcomponents and C1-inhibitor.

We have investigated the synthesis of C1q, C1r, C1s and C1-inhibitor in HepG2 cells, human umbilical vein endothelial cells (HUVEC), fibroblasts (skin and synovial membrane), chondrocytes and monocytes. C1q was only synthesised by monocytes, although the mRNAs for the C1qA and C1qC chains were expressed in HUVEC. C1r, C1s and C1-inhibitor were synthesised by all cell types. The secretion rates of C1r and C1s were approximately equimolar in fibroblasts and chondrocytes whereas the secretion rate for C1s exceeded that for C1r in the other cell types. Molar ratios of C1s to C1r were approximately 2:1 for HepG2 cells, 5:1 for monocytes and 10:1 for HUVEC. Stimulation with interferon-gamma resulted in increased expression of all four proteins. The C1s:C1r ratio did not alter in chondrocytes or fibroblasts, but approached unity in HepG2, monocytes and HUVEC, due to relatively greater stimulation of C1r gene expression.

Carcinoma, Hepatocellular↗
PubMed1992

N,O-diacylated-N-hydroxyarylsulfonamides: nitroxyl precursors with potent smooth muscle relaxant properties.

N,O-Diacylated-N-hydroxyarylsulfonamides are capable of slowly releasing nitroxyl (HNO) by simple, non-enzymatic hydrolysis in Krebs solution at 37 degrees C. Release of nitric oxide (NO) was not seen. These compounds were also found to elicit vasorelaxation in rabbit thoracic aorta in vitro, presumably as a result of their ability to release HNO. This effect was enhanced by the addition of superoxide dismutase (SOD). Thus, these results are consistent with previous work indicating that HNO is a potent vasorelaxant.

Animals↗
PubMed1992

Magnetic resonance imaging in occult spinal dysraphism.

A prospective study was carried out in 100 cases of suspected occult spinal dysraphic anomalies with Magnetic Resonance Imaging in order to determine its diagnostic efficacy as the initial imaging modality. MR imaging provided accurate preoperative information in 91 out of 92 cases (98.9%). Some of the unusual and interesting findings in the series were: presence of intrinsic cord abnormality in 19 out of 21 cases (90.4%) with a normal plain radiograph, 4 cases of diastematomyelia with a dermoid in the dorsal and lumbar region associated with syringohydromyelia, intradural fibrous/glial bands, syringohydromyelia/myelomalacia of the conus with tethered cord syndrome having a normally placed conus, and myelocystocele. It is concluded that MRI is an excellent primary diagnostic tool, together with a plain radiograph, for complete preoperative evaluation of mid-line spinal anomalies.

Adolescent↗
PubMed1992

Computed tomography evaluation of esophageal carcinoma.

Forty patients of histologically proven esophageal carcinoma were subjected to computed tomography (CT) with the objective to assess its reliability in preoperative evaluation of these patients. The findings were confirmed on surgery in twenty five of these patients, thought to be resectable. Bronchoscopy was performed to evaluate bronchial tree in cases of tumor of upper and middle third of esophagus. CT was found to be sensitive in predicting the location and size of tumor, in assessing invasion of tracheo-bronchial tree, spread to liver, celiac and left gastric nodes. However, it was not successful in picking up metastatic spread to local periesophageal nodes in five cases and celiac in one case. The study concluded CT should be carried out for preoperative evaluation of esophageal carcinoma to select operable cases and avoid unnecessary radicle surgery in advanced cases.

Adult↗
PubMed1992

Undescended testis: evaluation by magnetic resonance imaging.

We describe our experience of prospective magnetic resonance imaging (MRI) study in patients of undescended testis, with a 1.5 T equipment using body coil. There were thirty two patients, aged 1.5 to 14 years with a mean age of nine years. Surgical follow up was obtained for thirty one patients. We were able to indicate the position of 26 testes in 22 patients and absence of five testes in three patients. MRI was falsely positive and negative for five and two testes, respectively. Testicular tissue at ectopic site was identified by presence of characteristic signal intensity pattern, mediastinum testis and its location along empty spermatic canal in cases of inguinal testis either singly or in combination. MRI was able to detect atrophic changes in four testes, confirmed on surgery. The study concludes that MR imaging is useful in the localization and tissue characterization of a non palpable testis. However, it is not sensitive enough for complete exclusion of the diagnosis of an undescended testis. Thus a surgical or laproscopic exploration may be needed further in selective cases for the management of patient.

Abdomen↗
PubMed1992

Cranial sonography in preterm infants.

Fifty preterm newborn infants with gestational age of 28-36 weeks were subjected to real time cranial sonography to (a) evaluate the ventricular system and brain parenchyma, (b) determine the incidence of intracranial abnormalities, and (c) to establish the utility and advantages of routine cranial sonography in preterm infants. The lateral ventricular width varied from 6-12 mm (8.67 +/- 1.85 mm) while hemispheric width ranged between 3.68 to 3.95 cm with a mean of 3.84 +/- 0.25 cm. The lateral ventricular ratio ranged from 20.9 to 26.4% and it showed progressive decrease with increasing gestational age. Cavum septum pellucidum was found in 68% of the preterms. Incidental intracranial pathologies were detected in 12% of the preterms screened.

Anthropometry↗
PubMed1991

N omega-hydroxy-L-arginine: a novel arginine analog capable of causing vasorelaxation in bovine intrapulmonary artery.

This study describes the effects of N omega-hydroxy-L-arginine (NOHA) on endothelium dependent and endothelium independent relaxation of bovine pulmonary artery. These results are consistent with the hypothesis that NOHA is a biosynthetic intermediate in the production of nitric oxide from arginine. N omega-Hydroxy-L-arginine causes both endothelium dependent and endothelium independent vasorelaxation, similar to that of arginine. This NOHA elicited relaxation was also inhibitable by N-methylarginine, N-nitroarginine and N-aminoarginine.

Animals↗