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Biomedical subjects

S K Gupta

Publications and source records attributed to S K Gupta.

At least 631 records · Page 35Linked to original sources

Amino acid sequence of the alpha subunit of human leukocyte adhesion receptor Mo1 (complement receptor type 3).

Mo1 (complement receptor type 3, CR3; CD11b/CD18) is an adhesion-promoting human leukocyte surface membrane heterodimer (alpha subunit 155 kD [CD11b] noncovalently linked to a beta subunit of 95 kD [CD18]). The complete amino acid sequence deduced from cDNA of the human alpha subunit is reported. The protein consists of 1,136 amino acids with a long amino-terminal extracytoplasmic domain, a 26-amino acid hydrophobic transmembrane segment, and a 19-carboxyl-terminal cytoplasmic domain. The extracytoplasmic region has three putative Ca2+-binding domains with good homology and one with weak homology to the "lock washer" Ca2+-binding consensus sequence. These metal-binding domains explain the divalent cation-dependent functions mediated by Mo1. The alpha subunit is highly homologous to the alpha subunit of leukocyte p150,95 and to a lesser extent, to the alpha subunit of other "integrin" receptors such as fibronectin, vitronectin, and platelet IIb/IIIa receptors in humans and position-specific antigen-2 (PS2) in Drosophila. Mo1 alpha, like p150, contains a unique 187-amino acid stretch NH2-terminal to the metal-binding domains. This region could be involved in some of the specific functions mediated by these leukocyte glycoproteins.

Amino Acid Sequence↗

Monoclonal antibodies delineate multiple epitopes on the O antigens of Salmonella typhi lipopolysaccharide.

Fifteen monoclonal antibodies (MAbs) directed against Salmonella typhi were produced and characterized. The specificities of the antibodies were determined by their binding patterns in an enzyme immunoassay, with a panel of lipopolysaccharides isolated from different bacteria. Seven MAbs reacted with S. typhi, Salmonella enteritidis, and Salmonella dublin (all belonging to serogroup D). One MAb also reacted with Salmonella paratyphi A and S. paratyphi B. Five MAbs reacted with S. typhi, S. enteritidis, S. dublin, and S. paratyphi B. Two MAbs did not bind to any lipopolysaccharide but showed reactivity with bacterial sonic extracts isolated from S. typhi, S. paratyphi A, S. paratyphi B, Escherichia coli, and Shigella sonnei. These antibodies would be helpful in studying the complexity of antigenic determinants expressed by S. typhi and the nature of the antibody response during typhoid and paratyphoid fevers and also in the diagnosis of the disease.

Animals↗

Topical silver sulphadiazine--a new drug for ocular keratomycosis.

The efficacy of silver sulphadiazine in human keratomycosis has not been evaluated so far. Encouraged by the success of an earlier experimental trial, a prospective, controlled, randomised double masked clinical study was designed to evaluate the efficacy of 1% silver sulphadiazine ophthalmic ointment in 20 eyes of mycotic keratitis. Miconazole 1% was used for comparative evaluation in another 20 eyes. Silver sulphadiazine had a higher success rate (80% vs 55%) than miconazole. It had broad antifungal activity and was found to be effective in fusarium keratitis. Absence of side effects, economy, and its efficacy in deeper and extensive lesions were additional advantages. It is concluded from this study that silver sulphadiazine is a safe and effective broad spectrum antifungal agent which can be used for the treatment of human keratomycosis.

Administration, Topical↗

Intralobar sequestration of upper lobe of right lung--case reports.

Two cases of intralobar sequestration of the right upper lobe, which is supplied by a major anomalous collateral artery from the descending thoracic aorta and also by the upper lobe branch of the right pulmonary artery, are presented. Both cases underwent surgical correction. The plexus of abnormal vessels in the right upper lobe of the lung communicating to the anomalous collateral artery was unexpected. The return pathway into the right pulmonary artery was most unusual. The embryologic explanation of the anomaly and the surgical implications are discussed. The return pathway of the left-to-right shunt by a branch of the pulmonary artery is most unusual and has hitherto not been reported in English literature to the best of the authors' knowledge.

Adolescent↗

Histological study of follicular atresia in the ovary of the domestic hen (Gallus domesticus).

Semi-serial (1 in 20) sections of ovaries were studied and only two types of atresia were identified--non-bursting and bursting. Smaller, non-yolky follicles (less than 1 mm diameter) showed non-bursting atresia. Atresia in follicles greater than 1 mm diameter was invariably of the bursting type which involved the rupture of the follicular wall, and the extrusion of yolk and cellular debris through the rupture site into the stroma. However, this rupture site was small and consequently was not visible in every section but it could always be seen when the follicle was followed in semi-serial sections. The mitotic index of granulosa cells in bursting atretic follicles was much lower than that for normal follicles. The most common criteria for distinguishing non-bursting atretic follicles were the extremely shrunken, irregularly shaped oocytes and the separation of the granulosa from the theca. In bursting atretic follicles, reliable indications were the presence in the ooplasm of some cells or cellular debris, and disorganization of the yolk and granulosa tissue. The presence of pycnotic nuclei in the granulosa cells was not a consistent feature of all atretic follicles of the hen.

Animals↗

Response of toad urinary bladder to vasopressin analogs possessing V1 or V2 specificity.

The urinary bladder of the toad Bufo marinus has been used to examine the effect on sodium transport, measured by short-circuit current, of natural antidiuretic hormones and several synthetic peptide analogs. In mammals, these synthetic analogs show specificity for different receptors, designated V1 and V2 receptors, whose biological responses are mediated by phosphatidyl inositol breakdown products or adenylate cyclase activity, respectively. All analogs stimulated SCC, with relative potencies AVT greater than AVP greater than Phe2 OVT (V1 agonist) much greater than d(CH2)5Tyr(Me)AVP (V1 antagonist) = d(CH2)5[D-Ile2,Abu4]AVP (V2 antagonist). The V1 and V2 antagonists inhibited the SCC response to AVT and Phe2OVT, with similar inhibitory potencies. We conclude that the stimulation of sodium transport by antidiuretic hormones involves one hormone receptor which does not show the selectivity of mammalian antidiuretic hormone receptors, and may represent a more primitive type of receptor.

Animals↗

Evaluation of an enzyme immunoassay based on sonicate supernatant antigens of Mycobacterium w for immunodiagnosis of leprosy.

An enzyme immunoassay (EIA) based on sonicate supernatant antigens of a cultivable, atypical bacterium, Mycobacterium w (M. w), for immunodiagnosis of leprosy is described. M. w was selected after screening of sonicate supernatant antigens of seven cultivable mycobacteria in EIA. The results of the assay were compared with that of EIA using phenolic glycolipid-I (PGL-I). The M. w assay was more sensitive than PGL-I based EIA, for detection of leprosy patients of all categories, including long term treated patients with low bacterial load. The M. w assay was highly sensitive (93.49%) for detection of active LL patients, and the difference in the positivity of the two assays for LL patients was statistically significant (p 0.05). The combined positivity of the assays with M. w and PGL-I for LL was higher than that with either antigen alone. M. w assay, in addition, was also highly sensitive for detection of patients with active pulmonary tuberculosis.

Antigens, Bacterial↗