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Biomedical subjects

M Gupta

Publications and source records attributed to M Gupta.

At least 37 records · Page 2Linked to original sources

Differential contribution of nitric oxide to regulation of vascular tone in coronary conductance and resistance arteries: intravascular ultrasound studies.

We examined the role of nitric oxide in the maintenance of coronary vascular tone in 15 dogs. A 0.014 inch Doppler wire was introduced into the midsegment of the circumflex coronary artery and a 4.3F, 30 MHz two-dimensional ultrasound imaging catheter was introduced over the Doppler wire. Acetylcholine caused a dose-dependent vasodilation in both epicardial and resistance coronary arteries. However, N omega-nitro-L-arginine methyl ester (L-NAME), an inhibitor of nitric oxide synthetase caused a dose-dependent vasoconstriction mainly in the epicardial coronary arteries, partially reversed by L-arginine. The vasodilator response to acetylcholine was inhibited by L-NAME only in the epicardial circulation. Thus using combined intracoronary two-dimensional and Doppler ultrasound, we have demonstrated both basal and acetylcholine-induced release of nitric oxide in epicardial coronary arteries. The failure of L-NAME to decrease basal and acetylcholine-induced increases in flow velocity suggests that endothelium-dependent relaxation in coronary resistance vessels may not be mediated by nitric oxide alone.

Acetylcholine

Clinical immunology and infectious diseases.

Without the application of immunology, understanding of the pathogenesis and pathophysiology of infectious diseases would be severely retarded. The development new vaccines for the prevention of infectious diseases has been based on new immunologic findings. Immunodiagnostic modalities have provided for the growth of diagnostic techniques for infectious diseases. Clinical immunology also has laid the groundwork for immunotherapies using the old intravenous immunoglobulin preparations and the new monoclonal antibodies, cytokines, and interferons.

Adolescent

Clinical correlates of the gross, radiographic, and histologic features of urinary matrix calculi.

We present five patients with urinary matrix calculi, which, in contrast to the normally brittle calcigerous calculi, are soft, pliable, and amorphous. Common clinical features include a history of calcigerous stone disease, renal surgery, urinary obstruction or stasis, and chronic infection with Proteus species or coliforms. The diagnosis is usually made at surgery, but certain preoperative radiographic findings may be suggestive. Matrix calculi are radiolucent on plain abdominal films, although their appearance on nonenhanced CT scans is similar to that of calcigerous calculi despite their small mineral content. Extracorporeal shockwave lithotripsy is ineffective; open or percutaneous techniques are necessary. Histologic inspection reveals laminar concentric rings of organized matrix with an orderly, layered deposition of minerals. Histochemical investigation can provide insight into the possible sequence of events in normal calculogenesis. The successful management of urinary matrix calculi depends on a high index of suspicion and a thorough knowledge of their clinicopathologic features.

Adult

Basal cell carcinoma in blacks: a report of 15 cases.

We report 15 cases of basal cell carcinoma (BCC) in black patients seen in an office practice over a 15-year period. Review of the literature supports our view that nonmelanoma skin cancer in blacks is more prevalent than generally thought. The major etiological factor in BCC development is exposure to ultraviolet light. Skin pigmentation, however, provides some degree of protection. We suggest that BCC development in blacks and in nonexposed areas in whites may represent a different pathogenesis from BCC caused by ultraviolet light exposure.

Adult

Characterization of antigenic determinants on porcine zona pellucida-3 beta(ZP3 beta) glycoprotein by monoclonal antibodies.

Out of 11 monoclonal antibodies(MAbs) developed against porcine zona pellucida-3 beta(ZP3 beta) glycoprotein, 6 (MA-451, -454, -455, -462, -467 and -470) reacted with ZP2 beta, deglycosylated ZP3 beta(DGZP3 beta), and reduced and carboxyamidomethylated ZP3 beta(RCMZP3 beta) in ELISA and Western blot suggesting that these monoclonals recognise a linear protein epitope. Five MAbs(MA-452, -456, -459, -474 and -476) showed reduced binding with DGZP3 beta and RCMZP3 beta as compared to ZP3 beta in ELISA suggesting that these may recognize either carbohydrate moities or conformation dependent epitopes. Moreover, these MAbs failed to recognize these antigens on Western blot. Based on competitive inhibition studies in ELISA for the ability of MAbs to inhibit the binding of biotinylated ZP3 beta to solid phase antibody, 6 distinct domains were discernible. Domain V recognised by MA-467 partially overlaps with the domain corresponding to MA-454 and MA-455. All 11 MAbs reacted with zona pellucida of intact oocytes as revealed by indirect immunofluorescence but only 3 antibodies (MA-454, -455 and -467) delayed the zona lysis by trypsin. In immunoblots MA-467 recognised 18kDa fragment of RCMZP3 beta digested with endoproteinase lys-C and 37 and 30kDa bands of elastase digest of ZP3 beta. The results will help in delineation of functionally relevant domains and design of contraceptive vaccine based on zona pellucida aiming for pre-fertilization block.

Animals

Evaluation of culture techniques for detection of spontaneous bacterial peritonitis in cirrhotic ascites.

This prospective study was done in cirrhotic patients to evaluate ascitic fluid culture techniques by the conventional method and by an alternate method of bedside ascitic fluid inoculation into blood culture bottles, with an aim to improve bacteriological diagnosis of spontaneous bacterial peritonitis (SBP). Of the 300 patients who were evaluated, 43 who had a total leukocyte count greater than 500/mm3 or a polymorphonuclear cell count greater than 250/mm3 in ascitic fluid were included. There were 30 episodes of SBP in 28 patients and another 15 patients had culture-negative neutrocytic ascites (CNNA). Escherichia coli was the commonest organism cultured, being found in 60%. There was significantly greater (p < 0.001) ascitic fluid culture positivity with direct inoculation into blood culture bottles, i.e. 66.7% compared to 31.1% by conventional method at 48 hours, and this was evident even 24 hours after inoculation i.e. 33.3% positivity compared to 4.4%. Bacteremia was present in 53.3% of patients with SBP and 33.3% with CNNA. Ascitic fluid inoculation directly into blood culture bottles leads to a significantly increased percentage of culture positivity and reduces the time needed for detection of SBP from 48 to 24 hours.

Ascitic Fluid

Swallowed sharp foreign bodies (sewing needles): a conservative approach.

A swallowed foreign body, large or small, sharp or pointed should be treated with respect. Its passage in the gastrointestinal tract should be carefully watched and monitored. The patient should be kept under regular and constant observation until such time as the foreign body has either expelled itself or is removed. We report here two cases of sharp foreign bodies ingested by children and successfully managed on conservative lines.

Child

Zinc levels in maternal and cord blood and in amniotic fluid--a possible marker for foetal malformation.

Zinc levels were estimated from the maternal and cord blood drawn at delivery and in the amniotic fluid drawn before delivery in 9 pregnancies resulting in congenitally abnormal foetuses and 21 pregnancies resulting in normal healthy babies. Zinc levels were significantly lower (P < 0.01) in maternal and cord blood serum in congenitally malformed babies as compared to healthy normal controls. Amniotic fluid zinc levels were significantly higher (P < 0.01) in pregnancies with malformed babies. The use of zinc levels as marker for foetal malformation has been suggested.

Amniotic Fluid

Cranial ultrasonic assessment of infants with acute bacterial meningitis.

A prospective study was performed on 44 patients (newborn to one year old) with acute bacterial meningitis. Sonograms were obtained within 72 hours of diagnosis, and repeated on 7th, 14th or at an early date, if required. The spectrum of sonographic features of meningitis included normal scan (35.4%), echogenic sulci (63.7%) and parenchyma (29.5%), ventriculomegaly (59%), ventriculitis (35%), pseudo-porencephalic cyst (4.4%), extra axial fluid collection (4.4%), encephalomalacia (2.2%) and cerebral abscess (2.2%) in patients.

Acute Disease

Effect of leaf extract from Clerodendron colebrookianum on blood pressure in rats.

Hypotensive effect of the extract of leaves of C. colebrookianum was investigated. An extremely bitter fraction was isolated, which gave positive test for alkaloids. The fraction produced fall of blood pressure in a dose dependent manner. The fall of blood pressure was blocked by atropine. Hypertensive effects of adrenaline and noradrenaline were slightly antagonised by the alkaloidal extract.

Adrenergic alpha-Antagonists

Microsatellite instabilities at five chromosomes in primary breast tumors.

The microsatellite instabilities at nine loci of chromosomes 2p, 8p, 10p and 11p and the nm23-H1 locus on 17q21.3 were studied in primary breast tumors. Alterations in the short interspersed tandem repeats in tumor DNA in the form of either larger allele, smaller allele or LOH were observed. Significantly, a high occurrence of alterations in microsatellite polymorphisms at the ANK1, D8S135 and LPL loci of chromosome 8p (46-54%), the D2S119 locus of chromosome 2p (56%), the D10S197 locus at chromosome 10p (88%), and the nm23-H1 locus of chromosome 17q21.3 (46%) were observed in breast tumors. These results provide the first evidence for genomic instabilities at 2p, 8p and 10p in primary ductal and lobular breast carcinomas. No correlation has been found between the stage of the tumor and microsatellite instability, suggesting that microsatellite instability is an early genetic event in breast carcinogenesis.

Breast Neoplasms

An engineered mutant of vaccinia virus DNA topoisomerase I is sensitive to the anti-cancer drug camptothecin.

Although highly homologous to the other eukaryotic type I DNA topoisomerases, vaccinia virus DNA topoisomerase I is distinct in its resistance to the anti-cancer drug camptothecin. After comparison of available sequences of sensitive and resistant type I topoisomerases, the aspartic acid at position 221 of vaccinia virus topoisomerase I is mutated to a valine. The resulting mutant protein is partially active. In contrast to the wild type enzyme, the relaxation of supercoiled DNA is inhibited by camptothecin. Its cleavage reaction with DNA is enhanced by camptothecin due to inhibition of religation of DNA. This demonstrates that even though the size of vaccinia virus is only about one-third that of the other camptothecin-sensitive topoisomerases, it has a potential interaction site for camptothecin.

Amino Acid Sequence

Effects of exercise training and diabetes on cardiac myosin heavy chain composition.

This study determined whether the beneficial effects of exercise training on the diabetic heart previously observed are associated with alterations in ventricular myosin heavy chain (MHC) isoform composition. Diabetes was induced in rats by i.v. streptozotocin. Trained rats were run on a treadmill for 60 min/day, 27 m/min, 10% grade. After 10 wks, ventricular MHC isoenzyme protein composition was analyzed for MHC composition using gel electrophoresis. alpha-MHC and beta-MHC mRNA were determined by Northern and slot blot hybridization techniques. Both protein and mRNA analyses indicated that sedentary control rats exhibited a predominance of alpha-MHC. Sedentary diabetics exhibited a shift to beta-MHC. Exercise trained diabetic rats showed a predominance of beta-MHC. The results indicate that treadmill exercise training of diabetic rat does not prevent the diabetes-induced shift in MHC composition towards the beta-MHC isoform, thus it is unlikely that the beneficial effects of exercise training on the diabetic heart, previously shown, are due to a normalization of the myosin isoform composition.

Animals

Isolation and characterization of a rat ventricular cDNA expressed specifically in cardiac and skeletal muscles.

We describe the isolation of a novel cDNA named Myomy and show that its transcripts are present in skeletal and cardiac muscles as well as in differentiated Sol 8 skeletal muscle cell line. Sequence analysis revealed that neither nucleotides nor deduced protein product have any significant homology to those previously described. The encoded protein of Myomy cDNA consists of 76 amino acids and has a molecular weight of 8,000 dalton. Based on its muscle specific expression, low abundance and a higher occurrence of SP(T)XX, S(T)S(T)XX motifs, we suggest that Myomy encodes a new muscle specific transcription factor.

Amino Acid Sequence