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Biomedical subjects

S Basu

Publications and source records attributed to S Basu.

At least 289 records · Page 16Linked to original sources
PubMed1995

Exploiting temperature dependence to improve selectivity in membrane-based plasmapheresis.

Temperature effects on cross-flow membrane plasmapheresis have been investigated with the help of hydrophillic polyvinylidene fluoride (PVDF) Durapore membranes of pore size 0.65 micron and an effective filtration area 30 cm2, using a thin-channel device (Minitan-S, Millipore Inc., U.S.A.) and goat's blood as the working fluid. The filtration and sieving properties have been characterized by evaluating normal saline (0.9 g%) flux and the sieving coefficients of albumin, immunoglobulins, and fibrinogen respectively. Runs were performed at 10 +/- 1, 20 +/- 1, 30 +/- 1 and 40 +/- 1 degree C, the various filtration parameters were measured and samples of the feed and permeate were collected during steady state. It is seen that the "effective" pore size increases with temperature increase thereby increasing flux, sieving and fouling. Exploiting temperature effects can possibly help modify the sieving spectrum in membrane-based plasmapheresis.

Humans↗
PubMed1995

Dobutamine echocardiography and thallium-201 imaging predict functional improvement after revascularisation in severe ischaemic left ventricular dysfunction.

OBJECTIVES: To evaluate the concordance between thallium-201 uptake and echocardiographic wall thickening, which are both indicators of potentially reversible myocardial dysfunction, in patients with chronic ischaemic left ventricular failure and to assess their relative contribution to predicting improvement in regional function after revascularisation in a subgroup. PATIENTS AND METHODS: 45 patients with chronic ischaemic left ventricular dysfunction (mean (SD) ejection fraction 25 (8)%) underwent echocardiography before and after dobutamine infusion (10 micrograms/kg/min). Of these, 22 patients underwent rest echocardiography at a mean (SD) of 9 (1) weeks after revascularisation. 201Tl imaging was performed during dobutamine echocardiography and at rest, 1, and 4 h after treatment with sublingual glyceryl trinitrate on two separate days. Potentially reversible dysfunction was thought to be present when a myocardial segment contained a Tl score of > or = 3 (ascending score 1-4), or showed improved wall thickening of a dysynergic segment during dobutamine stimulation. RESULTS: Of the 201Tl protocols, the redistribution scan 1 h after treatment with glyceryl trinitrate best demonstrated myocardial viability. Concordance between 201Tl and dobutamine induced wall thickening was 82% (kappa = 0.59) for detecting potentially reversible myocardial dysfunction before revascularisation (n = 45). Regional function improved in 18 of 22 patients after revascularisation. There were 168 dysynergic segments before intervention. The sensitivity of echocardiography and 201Tl imaging for detecting "recoverable" or viable segments after revascularisation was 87% and 92% respectively and specificity was 82% and 78% respectively (P = NS). CONCLUSIONS: Dobutamine echocardiography and 201Tl imaging may be used to predict mechanical improvement in dysynergic segments after revascularisation in patients with chronic ischaemic left ventricular dysfunction.

Adult↗
PubMed1995

NIDDM is the major cause of diabetic end-stage renal disease. More evidence from a tri-ethnic community.

Diabetes is the single largest cause of end-stage renal disease (ESRD) in adults in the U.S. Insulin-dependent diabetes mellitus (IDDM) has been recognized for some time as an important cause of ESRD, but non-insulin-dependent diabetes mellitus (NIDDM) has been assumed, until recently, to rarely cause ESRD. The objective of this study is to determine the incidence of treatment of diabetic ESRD by diabetic type for three ethnic/racial groups: non-Hispanic whites, African-Americans, and Mexican-Americans. A population-based incidence cohort was assembled from all dialysis centers in Bexar (San Antonio) and Dallas counties in Texas. All patients with diabetic ESRD beginning dialysis between 1 December 1987 (Bexar) or 1 December 1988 (Dallas) and 31 July 1991 were identified. All non-hispanic whites and African-Americans and a 1/2 random sample of Mexican-Americans were approached for enrollment. Individuals were confirmed to have diabetes using the World Health Organization criteria. Diabetes typing was done using a computerized historical algorithm. Age-specific and age-adjusted incidence rates were obtained by diabetic type and ethnic/racial group. NIDDM causes the majority of diabetic ESRD: 59.5% for non-Hispanic whites, 92.8% for Mexican-Americans, and 84.3% for African-Americans. Mexican-Americans and African-Americans, respectively, have 6.1 and 6.5 times higher incidence of treatment for diabetic ESRD than non-Hispanic whites. NIDDM results in more ESRD than does IDDM. Minorities (African-Americans and Mexican-Americans) are at increased risk, and programs aimed at prevention of NIDDM-related ESRD must focus on them.

Adult↗
PubMed1995

Historical introduction of acupuncture in India.

Acupuncture, though originated in oriental countries in the ancient times but, its philosophical understanding is amazingly wide open to the modern medical science. Historically, records are there regarding its Indian origin. However, acupuncture practised today in Indian sub-continent mainly shows Chinese origin and its introduction to India was pioneered by Dr. B.K. Basu, the first Indian who learned Chinese acupuncture from mainland China during 1959. It is interesting enough to note that though acupuncture is successfully practised in India in a rejuvenated form for the last few decades but due to lack of proper Governmental support this thereby suffers from under utilization and under development. While WHO suggested for its wider application and development through concerted Governmental efforts.

Acupuncture Therapy↗
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↗