Biomedical subjects

S Basu

Publications and source records attributed to S Basu.

At least 55 records · Page 3Linked to original sources

PubMed1995

Genetic marker profile of primitive Kutia Kondh tribal population of Phulbani district (Orissa).

Blood samples from 330 Kutia Kondhs (a primitive tribal population of Orissa) were subjected to a battery of tests for genetic markers to find out the incidence of various blood group polymorphisms (ABO, MN, Duffy, JKa), serum proteins, sickling and G-6-PD deficiency. Predominance of O (39.09%) blood group for ABO, N blood group (53.44) for MN and Fya+b+ (55.72) for Duffy blood group, were observed. High incidence of Hp2-1 (39.33), SS (70.43) and CC (96.65) for haptoglobulin, C3 and transferrin respectively were seen. The overall frequency of sickling was observed to be 16.36 per cent. The sex-wise distribution of G-6-PD was 13.71 per cent for males and 1.84 for females.

Blood Group Antigens↗

PubMed1995

Glycosyltransferase activities in human meningiomas. Preliminary results.

The biosynthesis of a given glycosphingolipid is under the control of specific glycosyltransferases, while its catabolism is catalyzed by step-wise action of glycosidases. The net amount of glycolipids apparently result from the difference between these two processes. However, other parameters should be taken into consideration, such as intracellular recycling of catabolic products, membrane insertion, and membrane turnover. In order to establish a possible correlation between ganglioside expression in brain tumor and the activities of the enzymes involved in their metabolism, we analyzed the activities of specific sialyltransferases (SAT-1 and SAT-2), galactosyltransferase (GalT-4), N-acetylgalactosaminyltransferase (GalNAcT-1), and N-acetylglucosaminyltransferase (GlcNAcT-1) in 9 human meningiomas whose ganglioside pattern was characterized either by the predominance ganglioside GM3 (4 out of 9) or ganglioside GD3 (5 out of 9). The results indicated a strong correlation between the GM3/GD3 ratio and SAT-2 activity; to the contrary, SAT-1 activity did not show any correlation if compared with the Lc2/GM3 ratio. In all the samples where GM3 was the main ganglioside, little or no activity of GalNAcT-1 and GlcNAcT-1 was detectable.

Carbohydrate Sequence↗

PubMed1995

Is there a case for haemorheological screening in the haemocompatibility testing of materials?

Bio-interactions between a material and blood govern the compatibility of the material with the human body and, therefore, the single most important requirement for the blood interfacing implants/devices is haemocompatibility. The decisive events which control haemocompatibility occur at the molecular level and affect the various subphases of blood rheology. This effect on the already complex human blood rheology can be used to our advantage in the screening of blood-contacting materials. An attempt has been made in the present work to evaluate the haemocompatibility of materials based on changes in microrheological parameters of human blood. Samples of materials of equal surface area known to be haemocompatible (medical grade silicon, polyvinyl chloride from blood bags) and materials known to be extremely haemo-incompatible (pyrex glass, copper, cotton fabric, all commercial grade) were incubated at 37.4 degrees C in freshly drawn anticoagulated whole human blood, and changes in the haemorheological parameters (whole blood, plasma viscosity, intrinsic viscosity of red cells, platelet aggregation, albumin fibrinogen ratio) have been evaluated. The results of the study show that alterations in the haemorheological parameters are reliable indicators to the compatibility/incompatibility characteristics of well-known substances and that there is a case for haemorheological screening of biomaterials in the overall framework of haemocompatibility tests.

Absorption↗

PubMed1995

Red cell enzyme deficiencies in the tribal population groups of the Bastar District, Madhya Pradesh, India.

A total of 958 blood samples from Muria, Maria, Bhattra and Halba from the Bastar District in Madhya Pradesh (India) was collected and analyzed for glucose-6-phosphate dehydrogenase deficiency, pyruvate kinase, hexokinase, and adenylate kinase red cell enzyme deficiency using flourescent technique. The implications of findings of the presence of rare enzyme deficiencies are discussed.

Adenylate Kinase↗

PubMed1995

Detection of type specific human papillomavirus (HPV) DNA in cervical cancers of Indian women.

Commercial Vira Pap and Vira Type kits of Life Technologies Inc., U.S.A., were used to determine prevalence and type specific distribution of human papilloma viruses (HPV) in 18 biopsy samples of cervical carcinomas and 26 specimens of exfoliated cervical cells (swabs). The women were either attending out-patient's department of a suburban hospital or a cancer hospital in Calcutta, India. HPV DNA was detected in 9 biopsy specimens but not in any of the cervical swabs. Five of the 9 HPV positive biopsies had HPV DNA type 16/18. Neither HPV 6/11 nor HPV 31/33/35 DNAs were detected in any of these 9 specimens. Results indicated possible presence of HPV DNAs of types other than the above in at least 4 specimens.

Adult↗

PubMed1994

Mice lacking granulocyte colony-stimulating factor have chronic neutropenia, granulocyte and macrophage progenitor cell deficiency, and impaired neutrophil mobilization.

Mice lacking granulocyte colony-stimulating factor (G-CSF) were generated by targeted disruption of the G-CSF gene in embryonal stem cells. G-CSF-deficient mice (genotype G-CSF-/-) are viable, fertile, and superficially healthy, but have a chronic neutropenia. Peripheral blood neutrophil levels were 20% to 30% of wild-type mice (genotype G-CSF+/+) and mice heterozygous for the null mutation had intermediate neutrophil levels, suggesting a gene-dosage effect. In the marrow of G-CSF-/- mice, granulopoietic precursor cells were reduced by 50% and there were reduced levels of granulocyte, macrophage, and blast progenitor cells. Despite G-CSF deficiency, mature neutrophils were still present in the blood and marrow, indicating that other factors can support neutrophil production in vivo. G-CSF-/- mice had reduced numbers of neutrophils available for rapid mobilization into the circulation by a single dose of G-CSF. G-CSF administration reversed the granulopoietic defect of G-CSF-/- mice. One day of G-CSF administration to G-CSF-/- mice elevated circulating neutrophil levels to normal, and after 4 days of G-CSF administration, G-CSF+/+ and G-CSF-/- marrows were morphologically indistinguishable. G-CSF-/- mice had a markedly impaired ability to control infection with Listeria monocytogenes, with diminished neutrophil and delayed monocyte increases in the blood and reduced infection-driven granulopoiesis. Collectively, these observations indicate that G-CSF is indispensible for maintaining the normal quantitative balance of neutrophil production during "steady-state" granulopoiesis in vivo and also implicate G-CSF in "emergency" granulopoiesis during infections.

Animals↗

PubMed1994

Transfection of mu MDR 1 inhibits Na(+)-independent Cl-/-HCO3 exchange in Chinese hamster ovary cells.

We have used single-cell photometry to measure intracellular pH (pHi) for several MDR cell lines constructed by stably transfecting LR73 chinese hamster ovary fibroblasts with mutant and wild type murine MDR 1 genes. In addition, plasma membrane electrical potential (delta psi) has been measured for the same cells by the K+/valinomycin null point titration method using the ratiometric styryl probe di-4-ANEPPS. Both the untransfected, parental cell line and a cell line expressing substantial mutant MDR 1 protein (K432R/K1074R) that is unable to confer the MDR phenotype are found to have delta psi > or = -40 (+/- 5) mV and pHi < or = 7.16 (+/- 0.03) units. In contrast, MDR cell lines constructed by transfecting wild type mu MDR 1 cDNA are found to exhibit delta psi from 15 to 19 mV lower and pHi from 0.13 to 0.34 units higher. A cell line that overexpresses crippled MDR protein (S941F) that is not resistant to colchicine or doxorubicin, but which is resistant to vinblastine [Gros, P., Dhir, R., Croop, J., & Talbot, F. (1991) Proc. Natl. Acad. Sci. U.S.A. 88, 7289-7293], exhibits elevated pHi and slightly elevated delta psi, relative to LR73. Northern and western blot analyses confirm the substantial overexpression of the mu MDR genes and proteins in these lines, as well as the mild overexpression of endogenous hamster p-GP mRNA in some lines. In general agreement with previous studies that examined myeloma cells overexpressing hu MDR 1 protein [Roepe, P.D., Wei, L.-Y., Cruz, J., & Carlson, D. (1993) Biochemistry 32, 11042-11056] we find that overexpression of wild type mu MDR 1 protein inhibits Cl(-)- and -HCO3-dependent pHi homeostasis. Via single-cell photometry studies we now conclude that this is due to inhibition of Na(+)-independent Cl-/-HCO3 exchange (strict anion exchange or AE). As concluded previously for other MDR cells, decreased AE activity is not due to decreased expression of the exchanger; in fact, again similar to previous work [Roepe et al. (1993) Biochemistry 32, 11042-11056], we find increased levels of AE mRNA in some MDR cell lines. Models that may explain these data that are also consistent with the known physiology of cells that endogenously express MDR protein are suggested. These data are consistent with a model for MDR protein function wherein overexpression of the protein decreases delta psi and/or elevates pHi via Cl(-)- and -HCO3-dependent mechanisms.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1994

Enhanced intracellular delivery of doxorubicin by scavenger receptor-mediated endocytosis for preferential killing of histiocytic lymphoma cells in culture.

A conjugate of the antineoplastic drug doxorubicin (DXR) with maleylated bovine serum albumin (MBSA) was taken up by a human histiocytic lymphoma cell line (U937) through the high efficiency process of scavenger receptor-mediated endocytosis resulting in a sixfold higher intracellular concentration of the drug compared to that obtained when the free drug was administered. Compared to the free drug, the drug conjugate showed significantly higher cytotoxicity towards U937 cells presumably because of intracellular availability of a pharmacologically active form of the drug. The intracellular product released after lysosomal degradation of the drug conjugate was chromatographically identical to free DXR. These findings merit serious consideration in the development of new chemotherapeutic agents for the treatment of histiocytic malignancies.

Albumins↗

PubMed1994

Structure of the O-specific side chain of the lipopolysaccharide from Escherichia coli O126.

The polysaccharide isolated from Escherichia coli O126 lipopolysaccharide contains D-galactose, D-mannose, L-fucose, and 2-acetamido-2-deoxy-D-glucose in the molar ratios 1:1:1:1. The structure of the O-antigen of the lipopolysaccharide from E. coli O126 was established by compositional analysis, partial degradation, methylation analysis, and nuclear magnetic resonance spectroscopy. These studies revealed that the O-antigen is branched and built up of tetrasaccharide repeating units having the following structure: [formula: see text]

Carbohydrate Conformation↗

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↗