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Biomedical subjects

D Gupta

Publications and source records attributed to D Gupta.

At least 217 records · Page 12Linked to original sources
PubMed1993

Thermodynamic and kinetic studies on the mechanism of binding of methylumbelliferyl galactosides to the basic agglutinin from winged bean (Psophocarpus tetragonolobus).

The binding of winged bean basic agglutinin (WBA I) to 4-methylumbelliferyl (MeUmb) galactosides was examined by extrinsic fluorescence titration and stopped-flow spectrofluorimetry. Upon binding to WBA I, MeUmb alpha-galactosides show quenching in fluorescence intensity, decrease in UV absorbance with a concomitant blue shift, and decrease in fluorescence excited-state lifetimes. However, their beta-analogues show enhancement in fluorescence intensity, increase in UV absorbance with a red shift, and an increase in fluorescence excited-state lifetimes. This implies that the umbelliferyl groups of alpha- and beta-galactosides experience non-polar and polar microenvironments, respectively, upon binding to WBA I. Replacement of the anomeric hydroxyl group of galactose by 4-methylumbelliferyl moiety increases the affinity of resulting saccharides. Substitution of C-2 hydroxyl of galactose by an acetamido group leads to increased affinity due to a favorable entropy change. This suggests that acetamido group of MeUmb-alpha/beta-GalNAc binds to a relatively non-polar subsite of WBA I. Most interestingly, this substitution also reduces the association rate constants dramatically. Inspection of the activation parameters reveals that the enthalpy of activation is the limiting factor for the differences in the forward rate constants for these saccharides and the entropic contribution to the activation energy is small.

Acetylgalactosamine↗
PubMed1993

Functional brain organization, handedness, and immune vulnerability in musicians and non-musicians.

In the current investigation an approach has been made to explore possible relations between musical talent, left-handedness, anomalous dominance for verbal materials, and immune vulnerability. Fifty-one young adult musicians and non-musicians were tested with Wing's Standardized Tests of Musical Intelligence, with a handedness questionnaire, a dichotic listening task, and with a questionnaire assessing asthma/allergies, migraine and myopia. In addition, IgE, Ig total, beta-endorphin, testosterone, and estradiol were measured in blood serum. Musical talent was related to left-handedness and to anomalous dominance; immune vulnerability was found in female musicians, and in subjects with reversed dominance for language functions as well as in male left-handers, independently of musical talent.

Adolescent↗
PubMed1993

Cranio-metaphyseal dysplasia.

Cranio-metaphyseal dysplasia in two brothers, aged fourteen and twelve, is reported. Both brothers presented with deafness, repeated episodes of cold and cough and mouth breathing. Striking craniofacial configuration consisted of hypertelorism, prominent glabella and zygomatic arches, mandibular prognathism and overgrowth of middle third of face. Both patients had genu valgum deformity. Low intelligence and poor scholastic performance present in both brothers were attributed to deafness. Radiographic features consisted of obtuse mandibular angle, defective dentition, sclerotic frontal sinuses, sclerotic mastoids and temporal bones. Splaying of metaphyses of long bones was associated with mild sclerosis. Mild degree of widening of ribs was also present. One brother also had hallux valgus deformity. The radiographic and clinical differentiation of cranio-metaphyseal dysplasia and metaphyseal dysplasia (Pyle's disease) is highlighted.

Adolescent↗
PubMed1993

Ontogeny, circadian rhythm pattern, and hormonal modulation of 5 alpha-dihydrotestosterone receptors in the rat pineal.

Some physiological parameters of pineal 5 alpha-dihydrotestosterone receptor in the rat such as ontogeny, circadian rhythm pattern, and its modulation by various neuropeptides and neurotransmitters which have profound influences on the pineal hormone melatonin were examined. Pineal 5 alpha-dihydrotestosterone receptors measured at different ages of the animal revealed that on day 10 both cytosolic receptor (CR) and nuclear receptor (NR) levels were high. With growth and development both groups of receptors declined and during puberty started again to rise. During adulthood both receptors were high; however, NR rose further with full maturation. Both groups of receptors showed circadian rhythmicity. While the CR was significantly higher at 6.00 h than at any time point through 24 h, the NR peaked at 18.00 h when the difference between both groups was maximum. Castration caused significant increment of NR. Treatment of castrated animals with a low dose of testosterone propionate (0.25 mg) significantly stimulated both receptor groups, while treatment with a high dose (2.5 mg) failed to do so. Treatment with various substances such as antiandrogen, opioids, neuropeptides, and neurotransmitters significantly modulated the pineal androgen receptor population: cyproterone acetate and monosodium glutamate suppressed CR; growth hormone releasing hormone increased NR; growth hormone release inhibiting hormone had no significant effects on either group of receptors; exogenous melatonin and norepinephrine increased NR; beta-endorphin increased only NR, but methionine enkephalin stimulated both, and epithalamine had no significant effects on either group of receptors, but thymosin alpha 1 increased NR.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Treatment of pulmonary aspergilloma by endoscopic intracavitary instillation of ketoconazole.

The authors report a case of pulmonary aspergilloma in which a fungus ball was visualized and a biopsy specimen was obtained at fiberoptic bronchoscopy. The fungus ball was successfully treated with bronchoscopic instillation of ketoconazole. It appears that this approach can be useful in the treatment of patients who are high-risk candidates for pulmonary resection.

Adult↗
PubMed1993

[Modifying effect of light and electromagnetic field on development of mammary tumors induced by N-nitrosomethyl urea in female rats].

Female rats aged I month and older were kept indoors in darkness, under lighting for 24 hours or exposed to ordinary lighting (light--12 hrs; darkness--12 hrs). Three weeks after the beginning of the experiment, they received N-nitrosomethyl urea (NMU) treatment in the dose of 50 mg/kg, intravenously, at weekly intervals, and were exposed to alternating 50 Hz (AMF) or static 0.2 oersted, (DMF) electromagnetic field radiation for 3 hrs, daily. Under usual lighting conditions, NMU treatment was followed by the development of mammary gland adenocarcinoma (MGA) in 31% of the animals. However, AMF or DMF treatment was followed by a shorter period of latency, without affecting MGA frequency. Constant lighting was found to stimulate a sharp increase in carcinogenesis: MGA frequency in groups receiving NMU, NMU+AMF or NMU+DMF was 57, 81 and 61%, respectively; latency period dropped by half as compared with usual lighting conditions. Conversely, the rats constantly kept in darkness revealed significant inhibition of mammary gland carcinogenesis, MGA frequency in NMU, NMU+AMF or NMU+DMF groups being 3, 4 and 2%, respectively. A blood serum--hormone assay showed constant lighting to decrease melatonin level and to increase prolactin concentration for all the modalities of carcinogenic treatment used. The results point to a significant promoting effect of constant lighting on mammary gland carcinogenesis by NMU in rats. This effect is potentiated by additional AMF or DMF treatment. Conversely, constant darkness inhibits mammary gland carcinogenesis and mitigates the pernicious effect of low-frequency electro-magnetic radiation.

Animals↗
PubMed1993

[The role of melatonin in growth of malignant choroid melanoma].

Increasing evidence of the immunomodulatory and tumor-depressing effects of melatonin prompted us to study altered concentrations of this multifunctional pineal hormone in the aqueous humor of eyes with melanoma. Eyes undergoing cataract surgery served as controls. First, RIA was used for the detection of melatonin (5 melanoma and 8 control eyes). In a second series we used ELISA with a newly developed antibody (6 melanoma and 11 control eyes). Moreover, the supernatant media of cultured melanomas were investigated for melatonin. We cautiously interpret the results as follows: (1) in the morning melatonin is detectable in the human aqueous humor at a concentration of ca. 35 pg/ml; (2) as blood serum and aqueous humor levels did not correlate, melatonin is probably actively secreted by the ciliary body rather than passively filtrated; (3) there are no significant changes in melatonin concentration in the aqueous humor of melanoma eyes; this, however, does not mean that melatonin does not play a role in uveal melanoma growth; (4) cultured uveal melanoma cells can probably synthesize melatonin.

Aqueous Humor↗
PubMed1993

Lactose intolerance in idiopathic ulcerative colitis in north Indians.

The incidence of lactose intolerance in 60 patients with idiopathic ulcerative colitis (IUC) from northern India and the effect of disease activity and extent of colonic involvement on the occurrence of lactose intolerance, was studied. Twenty controls matched for age and sex were also studied using 50 g lactose hydrogen breath test. The incidence of lactose intolerance in patients with IUC (41.7%) was no different from that in the control group (40%). There was however, a significant difference (P < 0.05) in the incidence of lactose intolerance in patients with active colitis (59.1%) as compared to those with quiescent disease (31.5%).

Adolescent↗
PubMed1992

Thermodynamic and kinetic studies on the mechanism of binding of methylumbelliferyl glycosides to jacalin.

The binding of Artocarpus integrifolia lectin (jacalin) to 4-methylumbelliferyl (Meumb)-glycosides, Gal alpha Meumb, Gal beta Meumb, GalNAc alpha Meumb, GalNAc beta-Meumb, and Gal beta 3GalNAc beta Meumb was examined by extrinsic fluorescence quenching titration and stopped flow spectrofluorimetry. The binding was characterized by 100% quenching of fluorescence of Meumb-glycosides. Their association constants range from 2.0 x 10(4) to 1.58 x 10(6) M-1 at 15 degrees C. Entropic contribution is the major stabilizing force for avid binding of Meumb-glycosides indicating the existence of a hydrophobic site that is complementary to their methylumbelliferyl group. The second order association rate constants for interaction of these sugars with lectin at 15 degrees C vary from 8.8 x 10(5) to 3.24 x 10(6) M-1 S-1, at pH 7.2. The first order dissociation rate constants range from 2.30 to 43.0 S-1 at 15 degrees C. Despite the differences in their association rate constants, the overall values of association constants for these saccharides are determined by their dissociation rate constants. The second order rate constant for the association of Meumb-glycosides follows a pattern consistent with the magnitude of the activation energies involved therin. Activation parameters for association of all ligands illustrate that the origin of the barrier between binding of jacalin to Meumb-glycosides is entropic, and the enthalpic contribution is small. A correlation between these parameters and the structure of the ligands on the association rates underscores the importance of steric factors in determining protein saccharide recognitions.

Binding, Competitive↗
PubMed1992

Response of CFU-GM (colony forming units for granulocytes and macrophages) from intact and pinealectomized rat bone marrow to murine recombinant interleukin-3 (rIl-3), recombinant granulocyte-macrophage colony stimulating factor (rGM-CSF) and human recombinant erythropoietin (rEPO).

The present study provides evidence, for the first time, of a role of the pineal gland in the proliferation of CFU-GM under the influence of different cytokines. The degree of colony formation in different cytokine groups was evaluated after 24 h, 3, 7 and 10 days. The colony growth in the present type of bone marrow cell cultures slows after the 10th day and ceases after the 14th day of incubation. The results show that rGM-CSF and the combination of rGM-CSF with rIl-3 and with rEPO stimulate the colony formation of granulocytes and macrophages. A 50% general reduction in the colony number was noted in the pinealectomy group. Their pattern of response to the different cytokines was similar to that of the intact group. It is suggested that the pineal activity has a physiological role in important aspects of host defence mechanisms, such as the proliferation of CFU-GM.

Animals↗
PubMed1992

Effect of the pineal gland on circadian rhythmicity of colony forming units for granulocytes and macrophages (CFU-GM) from rat bone marrow cell cultures.

The present study provides evidence that the pineal gland has a physiological role in the proliferation of colony forming units for granulocytes and macrophages (CFU-GM). A biphasic circadian rhythm of CFU-GM proliferation in rat bone marrow cell cultures (BMC) from intact animals peaking at 0600 and 1800 was observed. Pinealectomy (Px) at 1600 obliterated the circadian rhythm patterns of CFU-GM. Afternoon injections of melatonin (1630, 20 micrograms/per day for 10 days) to Px animals restored the rhythmicity. When pinealectomy was done at 0800, the morning peak remained unaltered and the colony number at 1800 was higher than that found in the afternoon Px animals. In conclusion, the pineal gland or its main hormone melatonin seems to have a regulatory role in the proliferation of CFU-GM in rat BMC. Further, the expression of the activity of CFU-GM in rat BMC depends on the time when pinealectomy is done or melatonin is substituted.

Animals↗
PubMed1992

Diltiazem as adjunctive oral therapy in patients with chronic atrial fibrillation.

Digoxin frequently fails to control the heart rate in patients of chronic atrial fibrillation particularly during exertion. We have studied in 20 such patients the effect of adding diltiazem (180 mg/day) on resting and peak exercise heart rates. An attempt was also made to determine its effects on exercise tolerance by using treadmill and 6 minute walk test. Addition of diltiazem resulted in significant attenuation of heart rate both at rest and at peak exercise. The resting and exercise mean heart rates on digoxin alone were 98.9 +/- 21.5 b.p.m. and 160.2 +/- 35.68 b.p.m. respectively. After diltiazem this reduced to 78.7 +/- 12.30 b.p.m. at rest and 132.4 +/- 40.4 b.p.m. at peak exercise (p < 0.01). There was no significant effect on exercise tolerance. In conclusion, the addition of diltiazem substantially reduced the excessive heart rate response to exercise in digitalised patients of chronic atrial fibrillation.

Administration, Oral↗
PubMed1992

Evaluation of haemotherapy in thalassaemias (20 years of Indian experience).

Two hundred fifty-one patients of beta-thalassaemia ranging from 3 months to 15 years of age were evaluated. They were maintained on hypertransfusion regimen and received periodic transfusions of group specific packed red cells. These multiple transfused patients were subjected to the tests for detection of transfusion malaria, HBsAg and allo-antibodies against red cells. Malaria infection and HBsAg were detected in 6.4% and 15.5% of patients respectively, while allo-antibodies were detected in 15.5% of patients. Thirteen patients (5.18%) developed hypersplenism and associated pressure symptoms due to splenomegaly for which they underwent splenectomy. Postsplenectomy period was uneventful and showed marked decrease in the frequency and quantitative requirements of transfusions and overall improvement in health. The continuing steady improvement of the prognosis in thalassaemia secondary to hypertransfusion regimen required us to transfer attention to other problems involved in thalassaemia management such as problems of hypersplenism and problems of multiple transfusion.

Adolescent↗