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Biomedical subjects

S Sinha

Publications and source records attributed to S Sinha.

At least 325 records · Page 18Linked to original sources
PubMed1994

Abnormal physical architecture of the lipophilic domains of human sperm membrane in oligospermia: a logical cause for low fertility profiles.

Three different domains of human sperm membrane, viz., the hydrophobic domains, the aqueous compartments and the surface proteins were probed to evaluate the molecular dynamics in these microenvironments in normal as well as oligospermic cases. Decreased rotational motion of the stearic spin-labels, designated rigid lipid matrix affording hindrance to the protein rotation in spermatozoa of oligospermic patients. The intrinsic tight anchoring of thiol containing proteins led to their increased ordering on the spermatozoa of such individuals. Fluorescence polarization studies revealed weaker hydrophobicity around these sperm proteins in oligospermia. Thus, this study identifies abnormal molecular mobility in the limiting membranes of oligospermic cells.

Cell Membrane↗
PubMed1994

Liposarcoma of the mesocolon--case report of a rare lesion.

A middle-aged man with a 2-month history of lower abdominal pain was found to have a large left-sided abdominal lump. Radiological investigations (barium enema, ultrasound, and computed tomography scan) revealed a mass lesion in the area of the descending colon, the sigmoid colon, and the rectum. Flexible sigmoidoscopy showed only mucosal edema and luminal narrowing. At laparotomy, a diffuse thickening of both the descending and sigmoid mesocolon extending into the mesorectum was seen, which suggested an inflammatory pathology. A left hemicolectomy with Hartmann's procedure was performed. After obtaining a histopathological diagnosis of liposarcoma of the mesocolon, an abdominoperineal resection of the rectum was done. The patient was advised to undergo postoperative radiotherapy but he did not comply and was thereafter lost to follow-up.

Humans↗
PubMed1994

C3b receptor (CR1) genomic polymorphism in rheumatoid arthritis. Low receptor levels on erythrocytes are an acquired phenomenon.

The number of complement receptor 1 (CR1, CD35) molecules on erythrocytes is genetically determined by two codominant alleles. The numerical expression of CR1 on erythrocytes correlates with a HindIII-RFLP or CR1 gene using CR1-1, a complementary DNA probe. We have found low CR1 on erythrocytes in patients with rheumatoid arthritis (RA) in an Indian population. Low levels in RA patients may be acquired or genetically determined. Fifty-two patients with RA, 48 nonrelated healthy subjects and 19 consanguineous relatives of patients were genotyped. CR1 numbers on erythrocytes were quantitated by the enzyme-linked immunosorbent assay using monoclonal anti-CR1 antibody. Normal subjects and patients were followed up for a period of 6 months to evaluate the stability of their CR1 expression. The gene frequency for allele H and L (7.4- and 6.9-kb HindIII restriction fragment, respectively), which correlated with high and low expression of CR1 on erythrocytes was 0.77 and 0.23 in the normal controls. Gene frequency in RA patients was 0.78 and 0.22 for H and L allele, which did not differ significantly from either controls or relatives (0.80 and 0.20 for H and L allele, respectively). However, RA patients expressed fewer CR1 on erythrocytes within each genotype than their relatives and controls. CR1 on erythrocytes were found to be stable in consecutive samples in controls. In RA patients, the number varied between low and high during the course of the disease. The variation in number was significantly correlated (p < 0.05, r = -0.85 to -0.98) with disease activity as monitored by erythrocyte sedimentation rate. Our results suggest that low levels of CR1 on erythrocytes in patients with RA are not inherited, rather they are acquired during the course of the disease.

Adolescent↗
PubMed1994

Rearranged p53 gene with loss of normal allele in a low-grade nonrecurrent glioma.

We are studying the p53 gene profile in primary glial tumors by seeking alterations in the hybridization pattern of the tumor DNA probed with a p53 gene probe. This report documents a rearranged p53 gene with loss of the normal allele in a low-grade mixed glioma which has not recurred during 4-year follow-up. The tumor had a low 5-bromodeoxyuridine (BrdU)-labeling index and low AgNOR count. The p53 protein was not detected on immunochemical staining. To our knowledge, this is the first report of an altered p53 gene in a low-grade nonrecurrent glial tumor and highlights the presence of further checks and balances on the control of cell proliferation and other malignancy-associated phenotypes, even in an already-established tumor.

Alleles↗
PubMed1994

Comparative efficacy of biodegradable liposomes and microspheres as carriers for delivery of Vibrio cholerae antigens in the intestine.

The effect of the encapsulated antigens of Vibrio cholerae and their route of administration in induction of immune response was studied in experimental cholera. The antigenic proteins of V. cholerae El Tor strain KB207 were obtained by fractionation of cell-free lysate by high-performance liquid chromatography. The antigenic proteins were pooled and encapsulated in biodegradable liposomes and poly(D,L) lactic co-glycolic acid microspheres. Rabbits were immunized with free as well as encapsulated antigens by different routes. Liposome-encapsulated antigens delivered intraintestinally offered maximum protection. Orally or intraintestinally delivered antigens in microspheres failed to elicit a significant immune response, although as a carrier microspheres were comparable to liposomes when judged by the subcutaneous route. The results suggested that liposomes and microspheres could be used as carriers of protective antigens of V. cholerae for effective immunization.

Animals↗
PubMed1994

Clinical evaluation of a dual sensor, rate responsive pacemaker.

UNLABELLED: Dual sensor pacemakers should respond more appropriately during differing exercise modes than a single sensor device. The Topaz model 515 (QT and activity count [ACT] sensing) pacemaker shows appropriate rate response during treadmill exercise testing. We postulated that adjustments to relative sensor contribution should allow fine tuning of the onset of rate response. Eleven patients with this pacemaker were studied. Three standard exercise tests were performed with adjustment of sensor blending and activity threshold between each one. We also assessed the response to isometric exercise and a false positive activity signal. RESULTS: Times to 100 ppm (3.7 +/- 1.3, 4.4 +/- 2.0, 5.3 +/- 1.5 mins), times to peak rate (6.1 +/- 1.6, 5.6 +/- 1.4, 6.5 +/- 1.3 mins) and accelerations to peak (9.0 +/- 2.4, 9.2 +/- 5.3, 7.7 +/- 2.8 ppm/min) were measured in all three different sensor settings (QT = ACT, QT < ACT, and QT = ACT with decreased activity threshold). No significant difference in onset of rate response was seen between the three settings. Tapping (false-positive activity) provided a rapid rise in paced rate to 79 ppm from a resting value of 65 ppm. This came down to 71 ppm demonstrating satisfactory sensor cross-checking. Isometric exercise induced a moderate response from 65 ppm at rest to 74 ppm after 3 minutes. CONCLUSIONS: Satisfactory rate response was demonstrated in most patients to treadmill testing and to isometric exercise. However, small adjustments to relative sensor contributions do not predictably alter the onset of rate response.

Aged↗
PubMed1994

Cervical spondylosis: a review of 230 cases.

Between January 1981 and March 1991, 230 patients of cervical spondylosis were treated surgically. The choice of surgical approach was dependent on clinicoradiological presentation. Anterior discectomy was performed in 105 cases decompressive laminectomy in 119 cases and combined approach in 6 cases. In anterior discectomy group 89% showed improvement, 4% remained unchanged and 7% worsened. In decompressive laminectomy group 68% improved, 15% unchanged, 15% worsened and 1.6% died. In combined approach 66% showed improvement, 17% remained unchanged and 17% died. Anterior discectomy had less risk of overall complications than decompressive laminectomy.

Adult↗