Search PubMed⌕ Search

Biomedical subjects

D Gupta

Publications and source records attributed to D Gupta.

At least 235 records · Page 13Linked to original sources
PubMed1991

Further characterization of the saccharide specificity of peanut (Arachis hypogaea) agglutinin.

2-Dansylamino-2-deoxy-D-galactose (GalNDns) has been shown to bind to peanut (Arachis hypogaea) agglutinin (PNA) in a saccharide-specific manner. This binding was accompanied by a five-fold increase in the fluorescence of GalNDns. The interaction was characterized by an association constant of 0.15 mM at 15 degrees and delta H and delta S values of -57.04 kJ.mol-1 and -118.1J.mol-1.K-1, respectively. Binding of a variety of other mono-, di- and oligo-saccharides to PNA, studied by monitoring their ability to dissociate the PNA GalNDns complex, revealed that PNA interacts with several T-antigen-related structures, such as beta-D-Galp-(1----3)-D-GalNAc, beta-D-Galp-(1----3)-alpha-D-GalpNAcOMe, and beta-D-Galp-(1----3)-alpha-D-GalpNAc-(1----3)-Ser, as well as the asialo-GM1 tetrasaccharide, with comparable affinity, thus showing that this lectin does not discriminate between saccharides in which the penultimate sugar of the beta-D-Galp-(1----3)-D-GalNAc unit is the alpha or beta anomer, in contrast to jacalin (Artocarpus integrifolia agglutinin), another anti T-lectin which preferentially binds to beta-D-Galp-(1----3)-alpha-D-GalNAc and does not recognize beta-D-Galp-(1----3)-beta-D-GalNAc or the related asialo-GM1 oligosaccharide. These studies also indicated that, in the extended combining region of PNA which accommodates a disaccharide, the primary subsite (subsite A) is highly specific for D-galactose, whereas the secondary subsite (subsite B) is less specific and can accommodate various structures, such as D-galactose, 2-acetamido-2-deoxy-D-galactose, D-glucose, and 2-acetamido-2-deoxy-D-glucose.

Arachis↗
PubMed1991

Elevated prolactin levels in human aqueous humor of patients with anterior uveitis.

Evidence is accumulating that prolactin (PRL) may play a physiological role in the regulation of humoral and cell-mediated immune responses. On the basis of these observations, we measured levels in the serum and aqueous humor of 28 patients with cataract or anterior uveitis with concomitant cataract. Intraocular concentrations were measured in a range from 0.1 to 3.4 ng/ml. Whereas serum PRL levels failed to show significant differences between the two groups (P = 0.39), intraocular concentrations were significantly higher in uveitis patients (P less than 0.001). The level in aqueous humor did not reflect the serum concentration in either group. To the best of our knowledge, this is the first study measuring PRL concentrations in human aqueous humor.

Adolescent↗
PubMed1991

Flavonoid glycosides from Cassia alata.

Two new glycosides, chrysoeriol-7-O-(2"-O-beta-D-mannopyranosyl)-beta-D-allopyranos ide and rhamnetin-3-O-(2"-O-beta-D-mannopyranosyl)-beta-D-allopyranosid e, were isolated from the seeds of Cassia alata. The structures were established on the basis of chemical evidence and spectroscopic methods, especially NMR.

Carbohydrate Sequence↗
PubMed1991

Lung transfer components in hyperthyroidism.

Pulmonary functions were studied in twenty hyperthyroid non smoker patients. Their FVC, PEFR and MVV were significantly lowered while FEV1/FVC% and EFR25-75% were normal. Amongst the diffusion functions, Tlco, Dm and VA were reduced and VC increased, though these changes were not statistically significant. After the achievement of euthyroid state, statistically significant increase was seen in FVC, PEFR, MVV, Tlco120, Dm and VA with significant decrease in Vc from the basal levels. FEV1/FVC% and EFR25-75% were not affected. These observations suggest that the principal abnormalities in pulmonary functions in the hyperthyroid state are increased pulmonary capillary blood volume and respiratory myopathy, which are reversed as euthyroid state is achieved.

Adult↗
PubMed1990

Tumor-inhibiting activity in the rat pineal gland displays a circannual rhythm.

The aim of this study was to investigate whether the tumor-inhibiting activity present in the rat pineal gland undergoes seasonal fluctuations as do other pineal substances. Crude ethanol extracts of rat pineal glands were tested for tumor-inhibiting activity in an in vitro microbioassay using human erythroleukemia cells which could not be inhibited by melatonin. Highest activity was detected in summer and least inhibition and even stimulation were observed in winter. There were no differences in activity between animals of different age, sex, or strain. Therefore, season seems to be the factor that exerts the most important influence on the content of tumor-inhibiting activity in the rat pineal gland. Correlation with seasonality in the occurrence of cancer is discussed.

Animals↗
PubMed1990

Sex- and age-dependent nature of the cytoplasmic 5 alpha-dihydrotestosterone (DHT) binding site/receptor in bovine pineal gland.

Recent research has justified the presumption that the pineal gland plays a role in the regulation of the gonadal system in mammals. Evidence also exists for androgen receptors in pinealocytes. In the current study, our approach has been to assess the age- and sex-dependent nature of 5 alpha-DHT receptors in bovine pineal. Although no significant difference was noted between various groups of bulls, cows, peripuberal cows, and calves (male) for pineal weight, the cytoplasmic 5 alpha-DHT binding site/receptor content in the pineal gland differed significantly. While the males had a low androgen receptor concentration in the pineal (46 fmol/pineal), the females showed the highest (442 fmol/pineal). The peripuberal females without calves and calves (male) presented a 5 alpha-DHT receptor content in between (225 fmol/pineal; 138 fmol/pineal). When the data were related to unit weight of pineal tissue, the difference still existed. It is suggested that the concentration of cytoplasmic 5 alpha-DHT receptors reflects the cellular activity and they are inversely related. Further, low cytoplasmic receptors also indicate that most of it is confined to the nuclear sites, as generally suggested for other androgen-dependent tissues. In the light of these suggestions, it is possible that lowest cytosolic 5 alpha-DHT receptor concentration in the males, in reality, reflects a higher degree of cellular function and a high concentration of the receptors in the nuclear site. Similarly, the peripuberal cows and calves perhaps have more cellular activity in the pineal than the mature cows. The current investigation, for the first time, by directly estimating the androgen receptors/binding site in the bovine pineal gland, demonstrates the sex- and age-dependent nature.

Aging↗
PubMed1990

Effect of the mammary carcinogen 7,12-dimethylbenz[a]anthracene on pineal melatonin biosynthesis, secretion and peripheral metabolism.

The aim of this study was to establish whether the nocturnal peak concentrations of circulating melatonin are affected by a single dose of 7,12-dimethylbenz[a]anthracene (DMBA) in female Sprague-Dawley rats as used for mammary tumor induction. Prior to this, the circadian rhythms of melatonin (N-acetyl-5-methoxytryptamine) and 6-sulfatoxymelatonin, the main metabolic product of melatonin, were determined in female Sprague-Dawley rats. The cosinor analysis revealed significant circadian rhythms with very similar acrophases around 1.00 a.m. for both substances. To enable explanations for possible changes in plasma melatonin after DMBA treatment, the biosynthesis in the pineal and the major metabolic product in the liver, 6-sulfatoxymelatonin, were measured 2 and 7 days after DMBA. Plasma melatonin was depressed by 31-37% (p less than 0.05) 2 and 7 days after DMBA but the pineal melatonin content remained unchanged. 2 days after DMBA, pineal serotonin and N-acetylserotonin showed a transient elevation of 35% (p less than 0.025) and 25% (p less than 0.05), respectively. The plasma concentrations of 6-sulfatoxymelatonin were the same in DMBA- and vehicle-treated animals. An elevation of the 6-sulfatoxymelatonin/melatonin ratio indicated a relative increase in the metabolism of melatonin due to DMBA. The absence of an absolute increase in 6-sulfatoxymelatonin after DMBA could be caused by an additional shift within the spectrum of different metabolic products of melatonin due to the carcinogen. Possible mechanisms are discussed.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1990

Osteogenic sarcoma of the frontal sinus.

Occurrence of osteogenic sarcoma in the craniofacial bones is limited. The case presented here is only the second reported case of osteogenic sarcoma of the frontal sinus, occurring in an 80-year-old woman who presented with proptosis and developed neurologic symptoms. The radiographic appearance was of a diffuse opacity with thickening of the calvaria. Tumor tissue was adherent to the dura, and there was a fairly good initial response with the methotrexate sodium-cisplatin combination chemotherapy used, but the outcome was fatal.

Aged↗
PubMed1990

Calcified hypernephroma. A case report.

Pattern of classification in an renal neoplasm is variable. If calcium is located nonperipherally (within the mass) it is more likely to be a renal cell carcinoma. But peripheral calcification does not rule out malignancy.

Adult↗
PubMed1989

Stage-dependent depression of melatonin in patients with primary breast cancer. Correlation with prolactin, thyroid stimulating hormone, and steroid receptors.

Serum melatonin was determined over 24 hours in 35 patients with breast cancer with either a fresh primary tumor (n = 23) or a secondary tumor (n = 12) and in 28 patients with untreated benign breast disease (controls) having a fibroadenoma (n = 10), fibrocystic mastopathy (n = 14), or other breast diseases (n = 4). Circadian rhythms existed in all groups with acrophases at 2 a.m. A 50% depression of peak and amplitude occurred in the group of patients with primary breast cancer compared with age-matched controls (P less than 0.001, P less than 0.01). The peak declined with increasing tumor size: 27% at Stage T1, 53% at T2 (P less than 0.001), and 73% at T3 (P less than 0.05). In contrast, patients with secondary breast cancer, particularly those receiving antiestrogen therapy, had a melatonin peak similar to controls. These results demonstrated a transient depression of pineal melatonin secretion in primary breast cancer and indicated a dynamic role of the pineal gland in malignancy. To investigate some endocrine effects of a depressed melatonin peak, the 24-hour rhythms of prolactin (PRL) and thyroid stimulating hormone (TSH) were determined in patients with primary breast cancer and compared with patients with secondary breast cancer. The PRL had significant circadian rhythms in both groups; but acrophases occurred at midnight in patients with secondary breast cancer, and there were unusually high concentrations at noon in patients with primary breast cancer. Circadian rhythms were not seen for TSH, but the 24-hour average secretion was depressed by 45% (P less than 0.01) in patients with primary breast cancer. The abnormal concentrations of PRL and TSH in these patients could be due to a depressed melatonin peak normally serving as a central circadian synchronizer and modulator of the secretion of adenohypophysial hormones. Additionally, a positive correlation existed between the nocturnal melatonin peak and progesterone and androgen receptor concentrations in primary tumors indicating a direct involvement of melatonin in the growth control of breast cancer.

Adult↗
PubMed1989

Rhythm development in pineal and circulating serotonin, N-acetylserotonin, and melatonin in Syrian hamsters.

The ontogeny of diurnal rhythm patterns in the pineal and serum levels of melatonin, serotonin, and N-acetylserotonin was studied in Syrian hamsters (Mesocricetus auratus) from birth to adulthood. The pineal and blood specimens were collected at 1100 h and 0200 h, and the compounds were measured by radioimmunoassay (RIA) procedures. Pineal melatonin and serotonin did not show any circadian rhythm at day 5 of postnatal age. At this age N-acetylserotonin was undetectable in the light phase but became manifest at night. By 10 days of age pineal serotonin registered an established rhythm pattern, with a higher level during the day. The occurrence of circadian rhythm in pineal melatonin was delayed and manifested first at 25 days of age. At this age, the first detectable daytime level of N-acetylserotonin also occurred. Circadian rhythm in serum melatonin was also established at this age. The serum serotonin did not evince any rhythm pattern throughout the observation period, except at day 17 of postnatal age. The massive concentration of daytime serotonin in the pineal was not reflected in the circulatory system. For serum N-acetylserotonin there was no discernable day-night rhythm in all age groups, except at 25 days of age. The results show that the timing of the appearance of various compounds in the neonatal pineal is variable; the release of the substances does not always reflect their synthesis; the ontogenesis of circadian rhythm is a part of the maturational process; and 25 days of age is a rather critical time in development.

Animals↗
PubMed1989

Toy weapons and firecrackers: a source of hearing loss.

Although acoustic injury as a result of exposure to noisy toys and firecrackers has been reported previously, most of these studies have been conducted on adults. The purpose of this prospective study, conducted at the time of Deepawali, an Indian festival of fireworks, was two-fold: 1. to measure the acoustic output of representative samples of toy weapons and firecrackers and the intensity level at critical spectator points from the site of emission; and 2. to determine the auditory status of a cross section of the target population, involving 600 participants from various age groups, before and after exposure to firecracker noise at Deepawali. The average sound level at a distance of 3 m was 150 dB, thus exceeding the damage risk criterion for adults (i.e., 130 dB peak level). An average 30 dB persistent sensorineural hearing loss was found in 2.5% of the target population as a result of toy weapon/firecracker noise during Deepawali. The 9- to 15-year-old age group was most affected. A judicious approach in the manufacture and use of toy weapons and firecrackers, in addition to legal restraints, is advocated.

Adolescent↗