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Biomedical subjects

S K Gupta

Publications and source records attributed to S K Gupta.

At least 721 records · Page 40Linked to original sources
PubMed1985

Tibiotibial vein bypass grafts: a new operation for limb salvage.

Tibiotibial bypasses were performed with short (8 to 33 cm) segments of reversed autologous vein in 14 patients who did not have longer segments of usable vein. All patients faced imminent amputation unless they had an effective revascularization. Two patients died, one within 1 month of operation. One patient required below-knee amputation despite a patent bypass. Eleven patients (79%) have a patent bypass and a functional limb 6 to 50 months after operation. These good patency results even with several grafts inserted into isolated segments of tibial arteries, some with incomplete plantar arches, suggest that these short vein grafts may be superior to other vein grafts. Tibiotibial bypasses may improve limb salvage results in otherwise difficult circumstances.

Aged↗
PubMed1985

Bioeffective monoclonal antibody against the decapeptide gonadotropin-releasing hormone: reacting determinant and action on ovulation and estrus suppression.

A monoclonal antibody generated against the decapeptide gonadotropin-releasing hormone (GnRH) was effective in intercepting the bioactivity of the hormone; it blocked ovulation in rats. The antibody reacted optimally with the native hormone. Substitution of amide at the COOH terminus by a carboxyl group decreased immunoreactivity by a factor of 200. The antibody recognized the amino acid sequences 4-6, 7-10, and 4-10 to a variable degree, which suggests that the epitope has a conformation involving the entire molecule, with the NH2- and COOH-terminal regions probably in proximity. The antibody was also competent to suppress the progression of estrus in dogs, an indication that GnRH may play an inductive role in the reproductive function of dogs.

Animals↗
PubMed1985

Stage-dependent toxicity of N-acetyl-glucosamine to Plasmodium falciparum.

The effects of N-acetyl-glucosamine on growth of synchronized cultures of Plasmodium falciparum were assessed by morphological observations and by measurement of parasite incorporation of 3H-hypoxanthine. Inhibition of 3H-hypoxanthine incorporation was more marked during the later stages of the erythrocytic cycle. At concentrations of the sugar below 20 mM, however, the deleterious effects were mainly a result of failure of released merozoites to invade erythrocytes, rather than a failure of schizonts to mature or release merozoites. These results are compatible with the hypothesis that a lectin-like substance on the merozoite interacts with a surface glycoprotein on the red cell and that sugar residues on this glycoprotein may be involved in this recognition.

Acetylglucosamine↗
PubMed1985

Characteristics and bioefficacy of monoclonal antigonadotropin releasing hormone antibody.

Mouse hybrid cell clones secreting antigonadotropin releasing hormone monoclonal antibody were developed by fusion of SP2/O-Ag 1.4 myeloma cells with splenocytes of mouse immunized with gonadotropin releasing hormone (GnRH) tagged to tetanus toxoid. The product of hybrid cell clones obtained as ascites fluid from mouse peritoneal cavity had a titre of 10(6) (30-40% binding of 125I-GnRH) in radioimmunoassay. The antibody was IgG2a and Kappa. The association constant (Ka) of the product of hybrid cell clone P(8)16(62) for binding with GnRH was 1.2 X 10(9) L/mole. The monoclonal antibody (P(8)16(62)) was highly specific for the native GnRH and devoid of reactivity with thyroid releasing hormone as tested in competitive radioimmunoassay. The recognition for GnRH agonists by monoclonal was 387-fold less with D-Ser (But)6 des Gly10 GnRH ethylamide and 608-fold less with Bz1-His6 GnRH. Monoclonal anti-GnRH antibody was competent to neutralize the in vivo bioactivity of the hormone as evident by the block of estrus cycle and termination of pregnancy in mice. Termination of pregnancy in animals receiving anti-GnRH monoclonal could be prevented by administration of progesterone.

Abortion, Induced↗
PubMed1985

Role of the carbohydrate domains of glycophorins as erythrocyte receptors for invasion by Plasmodium falciparum merozoites.

Solubilized preparations of purified glycophorins and specific domains of these molecules were assessed for their effects as inhibitors of Plasmodium falciparum invasion of human erythrocytes in vitro. The ability of newly invaded merozoites to continue developing and incorporating [3H]hypoxanthine during a 24-h period after their invasion was used as an assay for merozoite invasion. Glycophorins A, B, and C were found to be equally effective as inhibitors. Previous studies had shown N-acetylglucosamine, a sugar component of glycophorins A and C but not B, to be an effective inhibitor. Accordingly, molecular domains common to all of the glycophorins were further assessed. Sialic acid was shown to act almost as effectively as N-acetylglucosamine, presumably because of the structural similarities between these sugars. The inhibitory ability of sialic acid is considerably enhanced when presented to the parasite in a clustered form, as in an oligosaccharide. The acetyl group of these sugars does not appear to play an essential role in this inhibition. How the P. falciparum merozoite recognizes and interacts with the sugar domains of the glycophorin molecule remains to be determined.

Animals↗
PubMed1985

Lack of inhibitory effects of alpha 1-acid glycoprotein (orosomucoid) on Plasmodium falciparum invasion of human erythrocytes.

There has been controversy whether the plasma protein, alpha 1-acid glycoprotein (AGP), is able to inhibit invasion of erythrocytes by P. falciparum merozoites. Because AGP resembles a typical cell membrane sialoglycoprotein, it has been proposed that it can inhibit the parasite from interacting with its sialoglycoprotein receptor on the erythrocyte surface. We therefore isolated and tested samples of AGP obtained from a series of separate individuals. For comparative purposes, we also tested AGP prepared from the plasma of patients with elevated levels of AGP, as well as AGP obtained from two commercial sources. The authenticity and purity of the AGP samples was established by SDS-PAGE, radial immunodiffusion, and crossed immunoelectrophoresis. Our results indicated that none of the nine samples tested had any significant inhibitory effects in our P. falciparum invasion assay system.

Electrophoresis, Polyacrylamide Gel↗
PubMed1985

Comparison of axillounifemoral and axillobifemoral bypass operations.

Routine use of axillobifemoral (ABF) bypass has been advocated because this operation is thought to achieve better patency than the axillounifemoral (AUF) procedure. In 5 years we performed 34 AUF and 22 ABF bypass operations for limb salvage in high-risk patients using 6 mm polytetrafluoroethylene grafts. Five-year cumulative life table patency rates for AUF bypasses were 71% with reoperation (secondary patency) and 44% without reoperation (primary patency). These values were not significantly different (p greater than 0.5) from those for ABF bypasses (77% and 50%, respectively). Five-year limb salvage results (AUF 73%; ABF 89%) were also not significantly different (p greater than 0.1). Correlation of arterial outflow characteristics with graft patency revealed that 78% of the patients who never had graft occlusion had occluded superficial femoral arteries (SFA) demonstrated at the first operation, while 79% of the patients who experienced graft closure had comparable SFA occlusions. Our aggressive approach to graft thrombosis included angiographic study of the inflow arterial system. This revealed that 16% of the failed grafts were associated with hemodynamically significant stenosis of the donor subclavian artery. Our results indicate that AUF bypass is the procedure of choice for unilateral limb ischemia in high-risk patients who require an axillary source and that patency of the SFA does not affect outcome. These results also emphasize the need to obtain angiographic evaluation of the inflow system.

Aged↗
PubMed1985

Sarcoidosis in India.

Sarcoidosis in India frequently presents in elderly males with a dissociation between extensive radiological changes and scanty clinical signs in the chest. Clubbing is not infrequent. Erythema nodosum, generalized lymphadenopathy, eye changes, and bone cysts are uncommon. Spontaneous resolution or asymptomatic course is very rare. Follow-up reports, whenever available, show that patients have frequent relapses which respond well to short courses of steroids. This comparative study shows a few differences between this series (of 90 cases diagnosed from 1957 to 1982), two different Western series and the World series. Detection and documentation of cases of sarcoidosis in India have been on the increase during the last few decades. Whether that is due to increase in incidence or awareness is difficult to say. In two special centres in India, the frequency of detection of the disorder varied between 61.2 (in a chest hospital in Delhi during 1957-74) to over 150 per 100 000 patients (Calcutta) attending a general hospital with a sarcoidosis clinic (1980-82).

Adolescent↗