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Biomedical subjects

D Gupta

Publications and source records attributed to D Gupta.

At least 253 records · Page 14Linked to original sources
PubMed1988

Metabolic correction of defects in the lipid anchoring of Thy-1 in lymphoma mutants.

Many plasma membrane proteins, including Thy-1, are anchored by a carboxyl terminal glycophospholipid. This unit is absent from the Thy-1 of several lymphoma mutants that synthesize the Thy-1 polypeptide but fail to express it at the cell surface. Recessive mutants of complementation groups A to C, E, and F contain Thy-1 mRNA of normal size, which suggests that their Thy-1 polypeptide is normal. To identify possible metabolic lesions, each mutant was grown with various supplements. The class F and B mutants exhibited a reversible induction of surface lipid anchored Thy-1 when grown with the aminoglycoside G418. Other aminoglycosides, sugars, and ethanolamine were inactive. These unexpected observations are discussed in the context of lipid anchor biosynthesis.

Animals↗
PubMed1988

The bridging of large osteoperiosteal gaps using 'Decalbone'.

'Decalbone' was prepared by partial decalcification of human bones obtained from recently amputated specimens. It was then stored in 80 to 90% ethanol in a domestic refrigerator. The decalbone was used to fill large osteoperiosteal gaps in 25 patients. The commonest lesion was a giant cell tumour (21 cases) and various long bones were affected. There were 6 failures with recurrence of the tumour in 3 and uncontrolled infection in 3. The remaining 19 cases were followed up for from 2 1/2 to 7 years. In 10 the decalbone incorporated well, but further reconstructive procedures were needed in 9. Our studies showed that incorporation began at around 6 to 9 months and was complete at about 2 years in the upper limb and 4 years in the lower limb. There was no clinical evidence of an immune response.

Adult↗
PubMed1988

Oral submucous fibrosis--a new treatment regimen.

Successful treatment of oral submucous fibrosis with local injections of chymotrypsin, hyaluronidase, and dexamethasone is reported. In resistant cases, surgical excision of the fibrotic bands with submucosal placement of fresh human placental grafts was found to be successful.

Chymotrypsin↗
PubMed1988

Medical school M.D. graduates' activities in research and teaching (Alberta medical schools--1973-85).

The paucity of clinicians entering research and teaching careers has been noted. This study examines the proportion of M.D. graduates from Alberta medical schools (with different selection and educational philosophies) who have chosen such careers, and discusses when the graduates' major research interests developed and the significance of the findings to future manpower requirements.

Alberta↗
PubMed1987

Determination of aspirin by pre-column transacetylation reaction of 3-aminophenol and reversed-phase high-performance liquid chromatography: simultaneous determination of aspirin, acetaminophen, and caffeine.

The accuracy of the measurement of aspirin by high-performance liquid chromatography (HPLC) is reduced by its hydrolysis into salicylic and acetic acids during sample preparation. The ready and quantitative transacetylation of 3-aminophenol by aspirin, giving 3-hydroxyacetanilide (which is stable), has been utilized as a pre-column reaction for the determination of aspirin either alone or in the presence of acetaminophen and caffeine by reversed-phase HPLC.

Acetaminophen↗
PubMed1987

Superior orbital fissure syndrome in trigemino-facial zoster.

A case of trigemino-facial zoster presenting as Superior Orbital Fissure Syndrome is reported. Geniculate ganglion involvement was limited to the vestibular branch of the cochleo-vestibular nerve, without any hearing impairment or facial palsy. This case clearly illustrates that herpes zoster cranialis is a polyneuropathy of multifocal asynchronous viral activity and can present in numerous forms.

Adult↗
PubMed1987

Plasma adrenocorticotropin, cortisol, and dehydroepiandrosterone response to corticotropin-releasing factor in normal children during pubertal development.

The adrenocorticotropin (ACTH), cortisol, and dehydroepiandrosterone responses to synthetic human corticotropin-releasing factor (CRF) were studied in 28 endocrinologically healthy children (age 1-16 yr) and in six adult volunteers (age 24-42 yr). CRF was given as an intravenous bolus (1 microgram/kg body weight) between 0900 and 1000 hr. Significant increments in ACTH and cortisol levels after CRF were observed in all subjects, with an ACTH peak value of 48.2 +/- 3.4 pg/ml at 10 min (p less than 0.001). The ACTH and cortisol response patterns after CRF did not change with age or pubertal maturation and did not differ in children and in adults. In contrast, the dehydroepiandrosterone response to CRF clearly was related to the stage of pubertal development. The peak value after CRF significantly increased from puberty stage 1 to puberty stage 5 (164 +/- 18 versus 779 +/- 86 ng/100 ml, p less than 0.001). In adults, the mean dehydroepiandrosterone peak value after CRF did not differ from that of P5 children. These results show that CRF can be given safely to children. The absence of age-dependent ACTH and cortisol responses and a dehydroepiandrosterone response changing with pubertal maturation points to the existence of factors involved in the control of adrenal androgen production other than ACTH.

Adolescent↗
PubMed1987

Growth hormone, somatomedin levels and growth regulation in Turner's syndrome.

In a total of 56 children and adolescents with Turner's syndrome (41 with karyotype 45,X) basal serum levels of somatomedin bioactivity, Sm-C/IGF-I (RIA), IGF II (RIA), GH response to arginine and GHRH (GRF(1-29)NH2), and spontaneous GH secretion during 5.5 h of deep sleep were determined in a cross-sectional manner. GH responses to GRF and arginine as well as IGF-II levels were found to be in the normal range. Levels of somatomedin bioactivity were higher than normal before a bone age of 10 years, in the low-normal range thereafter, and below normal in some patients. Levels of Sm-C/IGF-I were found normal before and low-normal after a bone age of ten years. There was a trend towards increasing Sm-C/IGF-I levels with age. In contrast to the normal pattern, spontaneous sleep-related GH secretion was declining with age and did not show the puberty-associated rise. These findings suggest a normally functioning growth hormone-somatomedin axis in Turner's syndrome with alterations of its functioning level occurring secondarily as a result of absent gonadal activation. In single patients abnormally low growth hormone and/or somatomedin secretion may be present.

Adolescent↗
PubMed1986

Anatomic basis of Arnold's ear-cough reflex.

A clinical survey of 500 patients revealed 4.2% incidence of Arnold's ear-cough reflex. The reflex was bilateral in 2.8% of the patients. It was also elicitable from the anterior meatal wall in 2% of the patients, thus questioning the classically taught distribution of Arnold's nerve. Arnold's nerve also mediates the auriculo-palatal, auriculo-lacrimal, auriculo-cardiac and the ear-vomiting reflexes; but these are less apparent and not so commonly encountered.

Cough↗
PubMed1986

Ontogeny of circadian rhythmicity for melatonin, serotonin, and N-acetylserotonin in humans.

The serum concentration of melatonin, serotonin, and N-acetylserotonin were measured by RIA procedures in 28 infants aged 1 week to 9 months. Blood specimens were obtained at 12:00 hr and 24:00 hr. A day-night difference in serum serotonin was present immediately after birth. A significant (P less than 0.001) decrease in serum serotonin concentrations at 12:00 hr and 24:00 hr was observed from the first month of age to the third to ninth month of age. A significant (P less than 0.05) difference in day-night N-acetylserotonin concentration is first seen at age 1-3 months. Serum melatonin concentrations, though detectable, did not show any day-night difference at birth. Melatonin concentrations progressively increased up to the third month of age, and a significant (P less than 0.01) day-night difference appeared thereafter. The results indicate that in humans the circadian organization for serotonin already exists at birth, and the circadian melatonin rhythm develops after birth.

Age Factors↗
PubMed1986

The pineal gland in relation to growth and development in children.

The biorhythm of melatonin in human newborns is established later than that of either serotonin or N-acetylserotonin. Towards the end of the first year of life, the melatonin rhythm is a well established phenomenon and its nocturnal increment is equal to that seen in the pre-school children. Following this period the magnitude of nighttime melatonin increment starts declining and is closely associated with advancing skeletal age. This association between the magnitude of nocturnal increment and skeletal age is also noted in pathological subjects, lower skeletal age with greater magnitude of increment or advanced skeletal age with less increment. Although no inverse relationship between plasma melatonin and gonadotropins could be detected in children, there emerged a marked negative association between melatonin and growth hormone. GRF-induced GH stimulation suppressed melatonin in children as well as in adults. Melatonin pretreatment blocked GRF-induced increment of GH in rats. When animals were given either melatonin or growth hormone, one suppressed the other. It is possible that melatonin-induced growth hormone suppression is somatostatin mediated.

Adolescent↗
PubMed1985

Evidence for modulation of melatonin secretion in men with benign and malignant tumors of the prostate: relationship with the pituitary hormones.

The serum levels of the pineal hormone melatonin were determined by radioimmunoassay (RIA) in 4-h intervals throughout a 24-h period in elderly men with different types of prostate tumors: benign prostatic hyperplasia (BPH, n = 13), incidental carcinoma (PCi, n = 5), and nonmetastasizing carcinoma (PC, n = 9), as well as in young men (YM, n = 10). Simultaneously, the pituitary hormones prolactin, growth hormone, luteinizing hormone and follicle-stimulating hormone were measured by RIA. All subjects were untreated and free of serious complaints, and they stayed in the same environment. The data were analyzed by the population mean-cosinor method, and linear correlation coefficients between the five hormones were calculated for each group. Melatonin showed significant circadian rhythms in young men and patients with BPH and PCi but not in patients with PC. Twenty-four-hour mean concentration (mesor) and amplitude were significantly increased in patients with PCi as compared to patients with PC. Prolactin showed significant circadian rhythms in young men and in patients with BPH, whereas patients with PCi and PC appeared to have ultradian variations. Growth hormone did not show significant rhythms in any of the groups; the mesors were elevated in all tumor groups as compared to young men. Gonadotropin mesors were elevated in all tumor patients as compared to young men; rhythms were not detected. Carcinoma patients showed different interhormonal correlations than all other groups. These results indicate that modulation of melatonin secretion, accompanied by changes in the pituitary hormone levels, may be related to development and growth of prostate cancer.

Aged↗
PubMed1985

Circadian rhythms in serum melatonin from infancy to adolescence.

The circadian rhythm of circulating melatonin was determined in 38 children, aged 1-18 yr. Serum melatonin concentrations at 2400 and 0300 h in children aged 1-5 yr were significantly (P less than 0.001) higher than those in older children [6-10 yr, puberty stage 1 (P1)]. Nocturnal melatonin levels also were significantly (P less than 0.01) higher in P1 subjects than in P2 subjects aged 9-12 yr. A further small decline was found from P2 to P4/P5 (P less than 0.05). Thus, the decline in the nocturnal melatonin surge is not exclusively related to pubertal development, but begins in infancy.

Adolescent↗
PubMed1985

Heterogeneity of rat FSH by chromatofocusing: studies on in-vitro bioactivity of pituitary FSH forms and effect of neuraminidase treatment.

This study concerned the resolution of rat pituitary FSH utilizing chromatofocusing. Among the 11 components resolved and positively identified, ten had apparent isoelectric points (pI) between 3.1 and 5.1. Approximately 1% of pituitary FSH eluted at pH 9.4. Treatment with varying amounts of neuraminidase followed by refocusing generated FSH components of higher pI values. Treatment with other glycosidases did not alter the elution characteristics in chromatofocusing, while exclusion chromatography established an inverse relationship between apparent molecular weight and pI. Dose-response curves of various FSH components and of the reference preparation in the current radioimmunoassay system were parallel to each other. A study of their in-vitro bioactivity, utilizing granulosa cells which produce a plasminogen activator due to FSH in a dose-dependent manner, provided the following evidence: increased acidity of the components led to an increase of maximum response and an increase of the dose necessary for half-maximum response. Considering the observed alterations in the heterogeneity of FSH with changing physiological states of the animal, it is concluded that qualitative changes of the FSH molecule are perhaps involved in a modulatory role in the biopotencies of the hormone.

Animals↗
PubMed1985

Heterogeneity of rat FSH by chromatofocusing: studies on serum FSH, hormone released in vitro and metabolic clearance rates of its various forms.

Rat pituitary FSH was fractionated by chromatofocusing between pH 6 and 3. Ten components were resolved having apparent isoelectric points between 3.1 and 5.1. A comparative study of pituitary FSH and FSH secreted in vitro by quartered pituitary glands in the presence and in the absence of gonadotrophin-releasing hormone (GnRH) revealed similar patterns of charged species of intracellular and released FSH. Although GnRH increased FSH secretion about fourfold, no influence on the pattern of charged species was observed. Utilizing exclusion chromatography and chromatofocusing, pituitary FSH was compared to serum FSH which had been extracted by immuno-affinity chromatography. The results demonstrate for serum FSH a larger molecular size and a relative shift to more acidic components. Metabolic clearance rates of eight FSH components separated by chromatofocusing were measured in adult male rats. Half-lives varied between 13 min and several hours. A correlation existed between decrease of isoelectric points and decrease of metabolic clearance rates. These findings suggest that all hypophysial FSH components are secreted into the circulation at similar rates and the more acidic FSH components which appear to contain increased sialic acid, have a longer circulatory half-life and are more abundant in serum. It is concluded that sialylation may be involved in modulating serum FSH levels.

Animals↗
PubMed1984

Studies on the age-dependent nature of the response to LHRH given via different routes.

The effect of synthetic LHRH on circulating levels of LH and FSH in three groups of male rats, prepubertal, pubertal and adult, was compared after intravenous, intraperitoneal and subcutaneous administration. In two further series of experiments, infusion of LHRH over 120 min or two i.v. bolus injection at an interval of 60 min were carried out. Blood was collected from individual animals at each time-point before and after LHRH administration. The results indicate that the responsiveness of LH and FSH to LHRH was dependent not only on the routes of injection but also on the maturation of the animals. The infusion of LHRH induced the greatest response of LH and FSH in all the groups of animals. The pubertal group demonstrated greater responsiveness of LH than the other two groups. The second bolus injection of LHRH after 60 min elicited a much greater response for both gonadotropins in all age groups than that following the first injection. This indicates the existence of a priming effect of LHRH on LH and FSH; this effect was observed in all groups irrespective of their maturational status.

Aging↗