Search PubMed⌕ Search

Biomedical subjects

S Basu

Publications and source records attributed to S Basu.

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

Analysis of glycosphingolipids by fluorophore-assisted carbohydrate electrophoresis using ceramide glycanase from Mercenaria mercenaria.

Polyacrylamide gel electrophoresis of fluorophore-labeled saccharides is a simple and sensitive separation method for glycan analysis. This method requires an aldehydic reducing carbon on the saccharide in order to react with the amine group of the fluorophore (8-aminonaphthalene-1,3,6-trisulfonic acid or 2-aminoacridone). We have used exoglycosidase-free ceramide glycanase from hard-shelled clam to expose the reducing terminal of the glycan in glycosphingolipid by cleaving the linkage between the glycan and the ceramide. The released glycan was used for fluorophore-assisted carbohydrate electrophoresis, in order to qualitatively determine its monosaccharide composition, chain length, and glycosidic linkages using linkage-specific glycosidases, including a beta 1-3,4 galactosidase from clam.

Animals↗
PubMed1994

Reverse redistribution of thallium-201 represents a low-risk finding in thrombolysed patients following myocardial infarction.

The aim of the study was to evaluate the prevalence and clinical significance of reverse redistribution on thallium-201 imaging in post-myocardial infarction patients who have undergone thrombolytic therapy. Sixty-two patients aged 35-79 (mean 60) years with proven myocardial infarction who had undergone thrombolysis were studied 6 weeks post infarction. Standard stress and 4-h redistribution imaging was performed with 201Tl following treadmill exercise. Separate day rest injection of 201Tl was given after sublingual nitroglycerine; imaging was performed at 1 h. Planar images were acquired in three standard views and semiquantitative segmental analysis of the images was performed from the unprocessed images. All patients had radionuclide ventriculography for the assessment of left ventricular ejection fraction and wall motion abnormality. Thirty-three patients also had coronary angiography. 201Tl scintigraphy revealed fixed defects in 19 patients, reversible defects in 22, and reverse redistribution in 21. Those with reverse redistribution had a significantly higher exercise capacity (P < 0.01). Mean (SD) left ventricular ejection fraction was 46 (12)% for those with fixed defects, 47 (9)% for those with reversible defects and 45 (15)% for patients with reverse redistribution (P = NS). The regional wall motion abnormality score was 8 (5), 11.8 (2.2) and 14.2 (6) respectively in patients with reverse redistribution, redistribution alone and fixed defects. Regions with reverse redistribution revealed less regional wall motion abnormality compared to the other two groups (P < 0.01). Fifteen patients demonstrated significant 201Tl uptake in the region showing reverse redistribution, with rest injection of 201Tl following sublingual nitroglycerine, suggesting viable myocardium in that region.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac Catheterization↗
PubMed1994

Corneal permeability to and ocular metabolism of phenyl substituted prostaglandin esters in vitro.

The corneal permeability to and metabolism of four phenyl substituted prostaglandin analogues have been studied in vitro. Porcine corneas were mounted in incubation chambers dividing each chamber into an epithelial and endothelial side compartment. The analogues were added to incubation medium on the epithelial side. The permeability coefficients of 17-phenyl-18,19,20-trinor-PGF2 alpha-1-isopropyl ester (PhDH100A), 15-keto-17-phenyl-18,19,20-trinor-PGF2 alpha-1-isopropyl ester (PhXA12), 13,14-dihydro-15-hydroxy (R, S)-17-phenyl-18,19,20-trinor-PGF2 alpha-1-isopropyl ester (PhXA34) and 13,14-dihydro-17-phenyl-18,19,20-trinor-PGF2 alpha-1-isopropyl ester (PhXA41) were determined to be in the range of 5.1-11.0 x 10(-6) cm x s-1. All analogues in the endothelial compartment had been hydrolysed to corresponding acids but any other metabolism of PhDH100A, PhXA34 and PhXA41 after 4 h of incubation was minimal. In contrast, PhXA12 free acid was extensively metabolised to the 13,14-dihydro metabolite. To investigate whether the porcine ocular tissues contain 15-hyroxyprostaglandin dehydrogenase (15-PGDH) activity, prostaglandin F2 alpha (PGF2 alpha) and PhDH100A were used as substrates. PGF2 alpha and the phenyl-substituted analogues were also tested for their capacity as substrate to 15-PGDH in general. The 15-PGDH activity was low in all ocular tissues. The capacity of various ocular tissues or purified 15-PGDH to metabolise PhDH100A was lower than with PGF2 alpha as substrate. PhXA34 and PhXA41 were found not to be metabolised by 15-PGDH. Thus, the phenyl substituted PG esters penetrated the cornea and in the process were hydrolysed to their corresponding acids. No appreciable further metabolism occurred except for PhXA12 which was reduced by delta 13-reductase.

Animals↗
PubMed1994

Survival among Mexican-Americans, non-Hispanic whites, and African-Americans with end-stage renal disease: the emergence of a minority pattern of increased incidence and prolonged survival.

We undertook this study to determine whether there is a significant difference in survival on treatment for end-stage renal disease between Mexican-Americans, non-Hispanic whites, and African-Americans. A database covering the years 1975 to 1986 was obtained from the Texas Kidney Health Program. Eight-eight percent to 90% of patients starting renal replacement therapy in Texas were included in this database. The patients were followed until death, for 3 years after successful transplantation, or until they were lost to follow-up. Life table analysis as well as age-adjusted analysis using the Cox proportional hazards model were performed comparing ethnic/racial groups, disease etiology, and treatment type. In life-table analyses, African-Americans and Mexican-Americans had a survival advantage in most age, disease, and treatment groups. With age adjustment, this survival advantage remained for all etiologies combined, for diabetes and hypertension cases, and for patients receiving hemodialysis in a center. Multivariate analysis revealed a persistent survival advantage for Mexican-Americans independent of traditional predictor variables, such as age, disease etiology, treatment type, or size of the center in which they received treatment. In this same analysis, African-Americans showed an advantage in the older age groups. Both African-Americans and Mexican-Americans on renal replacement therapy have an increased survival advantage compared with non-Hispanic whites. Given the additional burden of increased incidence of end-stage renal disease in these groups, the cost of renal replacement therapy for these minorities is disproportionately high. Further study should be aimed at elucidation of the mechanisms by which minorities achieve their survival advantage.

Adult↗
PubMed1994

Anti-ischaemic and haemodynamic effects of elgodipine, a potent new generation calcium antagonist, in chronic stable angina.

The effects of oral elgodipine, a new dihydropyridine calcium antagonist on ischaemia and left ventricular function were assessed by a single blind placebo controlled study in 12 patients with chronic stable angina. Graded treadmill exercise and echocardiography/Doppler were performed before and 90 min after single oral doses of elgodipine of 20 mg, 40 mg and 60 mg, or placebo, given at weekly intervals. Elgodipine significantly increased exercise time by 1.1, 2.0 and 2.4 min, (P < 0.001 in each case) and time to onset of angina by 1.1 (P < 0.01), 1.9 (P < 0.001) and 2.6 min (P < 0.001) with increasing doses of the drug. Angina was abolished in 50% of patients with significant improvement in ST depression at peak exercise (P < 0.001) with the 60 mg dose. Blood pressure fell significantly at rest and peak exercise with a corresponding significant increase in heart rate. Ejection fraction was increased by 7.8% (P < 0.001) and 8.4% (P < 0.001) as was the stroke volume by 9.3 ml (P < 0.001) and 12.5 ml (P < 0.001) at 40 mg and 60 mg respectively. Peak mitral A to E velocity ratio and total peripheral resistance decreased significantly in a dose related linear trend. Only minor side effects were noted and no patient required withdrawal from the study. The results demonstrate that oral elgodipine is a potent anti-ischaemic agent. An improvement in the echocardiographic parameters of left ventricular systolic and diastolic function was also seen.

Aged↗
PubMed1994

Comparison of radionuclide ventriculography and 2D echocardiography for the measurement of left ventricular ejection fraction following acute myocardial infarction.

To compare the measurement of left ventricular ejection fraction obtained by two-dimensional echocardiography and by radionuclide ventriculography in patients following acute myocardial infarction, 49 consecutive patients with acute myocardial infarction underwent echocardiography and radionuclide ventriculography on the same day, pre-discharge. Left ventricular ejection fraction was assessed by two blinded observers for each method and reproducibility was also assessed for each technique. The limits of agreement for the differences in ejection fraction (%) between the two methods was--11.4, 12.2; the mean difference 0.4 was not significantly different from zero. The limits of agreement for the intra- and inter-observer differences in ejection fraction by radionuclide ventriculography were--9.4, 7.6 and -8.6, 11.0, respectively; the mean differences--0.9 and 1.2 were not significantly different from zero. The limits of agreement for the intra- and inter-observer differences by echocardiography were--5.8, 6.6 and--8.9, 9.5 respectively; the mean differences 0.4 and 0.3 were not significantly different from zero. Thus, two-dimensional echocardiography compares well with radionuclide ventriculography for the assessment of ejection fraction without the disadvantage of radiation.

Adult↗
PubMed1994

Effect of cerebrospinal fluid drainage and/or partial exsanguination on tolerance to prolonged aortic cross-clamping.

Paraplegia as a consequence of spinal cord ischemia associated with procedures on the thoracic and thoracoabdominal aorta has been linked to the interaction of proximal hypertension with elevated cerebrospinal fluid pressure (CSFP) during aortic cross-clamping (AXC). CSFP reduction via cerebrospinal fluid (CSF) drainage is thought to significantly prolong the cord's tolerance to AXC. Likewise, partial exsanguination is reported to effectively reduce ischemic injury by controlling proximal hypertension. To evaluate the individual and collective efficacy of both techniques, 18 mongrel dogs (25 to 35 kg), divided into three equal groups, underwent a fourth interspace left thoracotomy AXC. Baseline proximal arterial blood pressure (PABP), distal arterial blood pressure (DABP), and CSFP were established and monitored at 5-minute intervals during 120 minutes of AXC, and for 30 minutes thereafter. Group I animals were partially exsanguinated prior to AXC to maintain PABP at a mean of 115 to 120 mmHg. Group II animals had sufficient (16 +/- 5 cc) CSF withdrawn to maintain a DABP-CSFP gradient, i.e., spinal cord perfusion pressure (SCPP) of 20 mmHg. Group III animals were treated with both CSF drainage and partial exsanguination in the same manner as groups I and II, respectively. Perioperative somatosensory evoked potential (SEP) monitoring evaluated cord function. Postoperative neurological outcome was assessed with Tarlov's criteria. SEPs degenerated approximately 22 minutes following AXC for groups II and III. In contrast, group I exhibited rapid (10 +/- 7 min) SEP loss. All five surviving group I animals displayed paralysis 48 hours postoperatively.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Determination of specificities of rabbit antisera against the O-antigenic polysaccharide from Escherichia coli O126.

Rabbit polyclonal antibodies against the lipopolysaccharide of Escherichia coli O126 were serologically characterized by ELISA. The antibody specificities were determined by studying the inhibitory effects of the methyl glycosides of both anomeric configurations of the constituent monosaccharides and the oligosaccharides derived from the O-antigenic polysaccharide of E. coli O126. It was found that, amongst the monosaccharides, beta-D-N-acetyl glucosamine was the most effective inhibitory sugar in the O126 polysaccharide and the major specificity of the polyclonal antibodies was found to be directed against the trisaccharide having the structure alpha-D-Galp (1-->3)-beta-D-GlcpNAc(1-->2)-D-Manp.

Animals↗
PubMed1994

The sialic acid-containing lipopolysaccharides of Salmonella djakarta and Salmonella isaszeg (serogroup O: 48): chemical characterization and reactivity with a sialic acid-binding lectin from Cepaea hortensis.

Lipopolysaccharides (LPS) of Salmonella djakarta and Salmonella isaszeg, as well as of a spontaneous R-mutant of S. djakarta were investigated as to their content in neuraminic acid (Neu) and its individual linkage. The two Salmonella serovars both belong to the O:48 serogroup of Salmonella, but to two different subgroups. LPS of both S-forms contained high amounts of Neu, although in different quantities, whereas the R-form was completely devoid of it. Methylation analysis indicated that Neu is exclusively terminally linked in S. djakarta whereas both terminal and 4-linked Neu were recognized in S. isaszeg. Although terminally linked, a sialidase from Arthrobacter ureafaciens was unable to split Neu even after prolonged incubation from both S-type LPSs. When LPS was first treated by mild alkali, however, the total amount of Neu from S. djakarta LPS and about 50% from that of LPS of S.isaszeg could be removed. In contrast, alkali-treated LPS, but also the non-treated one, proved to be effective inhibitors for a sialic acid-binding lectin from Cepaea hortensis. The resistance of terminal Neu towards sialidase may be due to the presence of an O-acetyl group which would be removed during the methylation analysis but would, especially when linked to C-4, not interfere with the reactivity of the lectin.

Animals↗
PubMed1994

Structural studies of the side chain of outer membrane lipopolysaccharide from Pseudomonas syringae pv. coriandricola W-43.

The lipopolysaccharide (LPS) was isolated from Pseudomonas syringae pv. coriandricola W-43 by hot phenol-water extraction. Rhamnose and 3-N-acetyl-3-deoxyfucose were found to be the major sugar constituents of the LPS together with N-acetylglucosamine, N-acetylgalactosamine, heptose, and 3-deoxy-D-manno-octulosonic acid (Kdo). The main fatty acids of lipid A of the LPS were 3-OH-C:10, C12:0, 2-OH-C12:0, and 3-OH-C12:0. The O-specific polysaccharide liberated from the LPS by mild-acid hydrolysis was purified by gel permeation chromatography. The compositional analysis of the O-specific polysaccharide revealed the presence of L-rhamnose and 3-N-acetyl-3-deoxy-D-fucose in a molar ratio of 4:1. The primary structure of the O-specific polysaccharide was established by methylation analysis together with 1H and 13C nuclear magnetic resonance spectroscopy, including two-dimensional shift-correlated and one-dimensional nuclear Overhauser effect spectroscopy. The polysaccharide moiety was found to consist of a tetrasaccharide rhamnan backbone, and 3-N-acetyl-3-deoxy-D-fucose constitutes the side chain of the branched pentasaccharide repeating unit of the polysaccharide.

Carbohydrate Sequence↗
PubMed1994

Characterization of domains of herpes simplex virus type 1 glycoprotein E involved in Fc binding activity for immunoglobulin G aggregates.

Herpes simplex virus type 1 glycoproteins gE and gI form receptors for the Fc domain of immunoglobulin G (IgG) which are expressed on the surface of infected cells and on the virion envelope and which protect the virus from immune attack. Glycoprotein gE-1 is a low-affinity Fc receptor (FcR) that binds IgG aggregates, while gE-1 and gI-1 form a complex which serves as a higher-affinity FcR capable of binding IgG monomers. In this study, we describe two approaches used to map an Fc binding domain on gE-1 for IgG aggregates. First, we constructed nine plasmids encoding gE-1/gD-1 fusions proteins, each containing a large gE-1 peptide inserted into the ectodomain of gD-1. Fusion proteins were tested for FcR activity with IgG-sensitized erythrocytes in a rosetting assay. Three of the fusion proteins containing overlapping gE-1 peptides demonstrated FcR activity; the smallest peptide that retained Fc binding activity includes gE-1 amino acids 183 to 402. These results indicate that an Fc binding domain is located between gE-1 amino acids 183 and 402. To more precisely map the Fc binding domain, we tested a panel of 21 gE-1 linker insertion mutants. Ten mutants with insertions between gE-1 amino acids 235 and 380 failed to bind IgG-sensitized erythrocytes, while each of the remaining mutants demonstrated wild-type Fc binding activity. Taken together, these results indicate that the region of gE-1 between amino acids 235 and 380 forms an FcR domain. A computer-assisted analysis of the amino acid sequence of gE-1 demonstrates an immunoglobulin-like domain contained within this region (residues 322 to 359) which shares homology with mammalian FcRs.

Amino Acid Sequence↗
PubMed1994

Characterization of DNA polymerase-alpha/primase complex from developing embryonic chicken brains.

DNA polymerase-alpha and primase activities present in a complex, have been isolated, partially purified, and characterized from embryonic chicken brain. DNA polymerase-alpha activity, characterized by its sensitivity to N-ethyl-maleimide, high sedimentation coefficient (11.3 S), and acidic isoelectric point (5-5.5) was found in all embryonic ages. Primase activity, the enzyme responsible for the initiation of DNA synthesis, co-sedimented with DNA polymerase-alpha activity on a continuous glycerol velocity gradient. A complex containing both DNA polymerase-alpha and primase activities was isolated by DE-23 cellulose column chromatography of cell-free extracts of different embryonic ages of chicken brain. In addition to the primase complexed with DNA polymerase-alpha, a free primase activity was isolated by DE-23 cellulose column chromatography of an ammonium sulfate (0-45%; w/v) precipitated fraction of embryonic chicken brain cell-free extract. DNA polymerase-alpha activity from developing chicken brains in the embryonic stage was purified by immuno-affinity column chromatography. Of all the single-stranded DNA templates tested, primase activity was found to be maximally active with poly dC. Primase activity was not inhibited by a high concentration of alpha-amanitin. The results obtained may provide insight into further understanding of regulation of chromosomal DNA replication in developing tissues.

Animals↗
PubMed1994

Lipomatous hypertrophy of the interatrial septum.

Lipomatous hypertrophy of the interatrial septum, a finding associated with obesity and advancing age, consists of accumulation of adipose tissue including fetal adipose tissue in the interatrial septum. It is a rare lesion of the heart and can reach notable size. A case is reported in which the diagnosis of lipomatous hypertrophy of the interatrial septum was established intraoperatively; the large bulk of the lipoma was such that it required major reconstruction of the interatrial septum and right and left atrial walls.

Aged↗
PubMed1994

Study of finger and palmar dermatoglyphics in primary infertile males.

Finger and palmar dermatoglyphic variations have been studied in 160 diagnosed primary infertile males (111 clinically abnormal primary infertile males and 49 clinically normal primary infertile males). It has been observed that loops occur most frequently in primary infertile males. Arches are found to be absent on digit IV and V. Among the clinically normal infertile males the mainline formula 7.5.5--succeeds 11.9.7--instead of 9.7.5--in the order of preponderance. Bilateral and inter-group differences among clinically abnormal and normal infertile males have been found to be statistically non-significant for finger and palmar comparison. The present findings are compared with the result on finger and palmar dermatoglyphics of controls (130 Punjabi males of Delhi). Clinically normal infertile males show statistically significant differences in the occurrence of various pattern types of finger balls when compared with controls. Similarly, clinically abnormal as well as normal primary infertile males reveal statistically significant results in the occurrence of patterns in the hypothenar and Thenar/I interdigital area of palms when compared with controls.

Adult↗