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Biomedical subjects

S Burstein

Publications and source records attributed to S Burstein.

At least 55 records · Page 3Linked to original sources
PubMed1989

A new test of combined pituitary-testicular function using the gonadotropin-releasing hormone agonist nafarelin in the differentiation of gonadotropin deficiency from delayed puberty: pilot studies.

There is evidence that the capacity to synthesize gonadotropins is less in teenage boys with gonadotropin deficiency (GD) than in those with constitutional delay of puberty (DP). We hypothesized that this might predispose the latter group to have a greater pituitary-testicular response to the potent long-acting GnRH agonist nafarelin. We evaluated GD patients 14.3-24.0 yr of age (n = 8) and prepubertal DP boys 14.8-17.6 yr of age (n = 3). In most subjects the response to nafarelin was compared to that of frequent nocturnal blood sampling for LH and testosterone levels. All subjects received a single dose of nafarelin (1.0 micrograms/kg, sc), and blood was then sampled at 0.5- to 4.0-h intervals for 24 h. Patients with GD could not be distinguished from those with DP by pubertal staging criteria or by baseline values of LH, FSH, or testosterone. Patients with GD exhibited no rise in plasma LH levels during sleep, in contrast to those with DP. All GD patients had LH and FSH responses distinctly less than those of the DP group between 3-24 h postnafarelin. The peak incremental responses of GD and DP to nafarelin were, respectively: LH, 5.5 +/- 2 3 (+/- SEM and 77.2 +/- 8.6 IU/L (P less than 0.02); FSH, 2.7 +/- 1.2 and 9.4 +/- 0.8 IU/L (P less than 0.005). Testosterone peak responses were lower as well (0.26 +/- 0.2 vs 1.6 +/- 0.5 nmol/L, P = 0.05). This pilot study suggests that the response to a single test dose of nafarelin distinguishes GD from DP in the teenage years as well as does measurement of nocturnal LH levels. The testosterone response to the GnRH agonist adds a new dimension to GnRH testing. Nafarelin also allows assessment of the bioactivity of endogenous gonadotropin, is a more potent stimulus of pituitary-testicular function than endogenous GnRH secretion, and is more cost-effective than nocturnal sampling.

Adolescent↗
PubMed1989

In vitro susceptibility of Shigella strains isolated from stool cultures of dysenteric patients.

A reprospective analysis was conducted on the susceptibility by diffusion of 100 Shigella strains to 8 antimicrobial agents. These strains were isolated from 852 stool cultures obtained from dysenteric patients seen between January 1986 and April 1987. Seventy-one per cent of the samples from which Shigella sp were isolated were obtained from children under age 6 years; 86% of these samples revealed pus, with or without blood. The Shigella serotypes isolated most often were S. flexneri (57%) and S. sonnei (38%). The highest susceptibility rates were observed with furazolidone (98%), nalidixic acid (97%), and gentamicin (90%). The same strains were significantly less susceptible to other antimicrobial agents used to treat shigellosis; among them, ampicillin and trimethoprim-sulfamethoxazole, for which susceptibility rates of 40% and 64%, respectively, were observed. Thus, it is important 1) to evaluate regularly the in vitro susceptibility of Shigella sp strains to antimicrobials commonly used to treat shigellosis, and 2) to conduct controlled clinical trials on the efficacy of alternative drugs in treating this disease.

Anti-Bacterial Agents↗
PubMed1988

Three-year results of a randomized prospective trial of methionyl human growth hormone and oxandrolone in Turner syndrome.

Seventy girls with Turner syndrome, 4 to 12 years of age, participated in a prospective, randomized study to determine the effects on growth of methionyl human growth hormone (met-hGH) or oxandrolone. Subjects were randomly assigned to receive either no treatment (control) or met-hGH (0.125 mg/kg three times per week), oxandrolone (0.125 mg/kg/day), or combination met-hGH plus oxandrolone. At the end of an initial period of 12 to 20 months, patients in the original control and oxandrolone groups were given combination met-hGH plus oxandrolone. At that time the dosage of oxandrolone was lowered to 0.0625 mg/kg/day. Sixty-five subjects have now completed the first 3 years of the study. Compared with the control growth rate for year 1 (3.8 cm/yr), significant increases in growth rate were seen in all 3 years of combination therapy (9.8, 7.4, and 6.1 cm/yr, respectively) and in the first 2 years of treatment with met-hGH alone (6.6, 5.4, and 4.6 cm/yr). When growth velocity was expressed as standard deviation for age in girls with Turner syndrome, significant increases relative to the control group for year 1 (-0.1 SD) were seen in all three years of both combination therapy and met-hGH alone (combination, +6.6, +4.3, +3.0 SD; met-hGH, +3.1, +2.0, +1.4 SD). After 3 years of treatment, predicted adult height by the method of Bayley-Pinneau increased 4.5 cm in the met-hGH group and 8.2 cm in the combination group.

Body Height↗
PubMed1987

A major metabolite of delta 1-tetrahydrocannabinol reduces its cataleptic effect in mice.

The results described here demonstrate that THC-induced catalepsy in mice can be substantially inhibited by the prior administration of delta 1-THC-7-oic acid, the major metabolite of THC in most species including humans. This raises the possibility that the intensity and duration of action of THC may depend to a large degree on the levels of this metabolite at the sites of action.

Animals↗
PubMed1987

Isolated gonadotropin deficiency in boys: clinical characteristics and growth.

Analysis of the clinical findings and growth in 20 boys with isolated gonadotropin deficiency revealed a heterogeneous group of physical abnormalities. Ten of these patients were hyposmic or anosmic (Kallmann syndrome). Abnormalities found in our patients included undescended testes, gynecomastia, and ocular or skeletal anomalies. Regardless of the presence of hyposmia, patients without testicular enlargement (less than 2 cm3), had serum luteinizing hormone (LH) responses to luteinizing hormone-releasing factor (LRF) that were the same as in prepubertal boys. By contrast, five boys with testicular enlargement (greater than 2 cm3), some of whom had hyposmia, had a greater serum LH response to LRF than did prepubertal boys. Adrenarche was moderately delayed; although all boys initially had normal serum levels of dehydroepiandrosterone-sulfate, four boys eventually developed elevated serum levels. Bone ages were delayed compared with chronologic age in boys who had the condition after 15 years of age. The rate of linear growth was normal, and final adult heights were normal with testosterone therapy, although linear growth continued longer in these boys than in boys with normal pubertal progression. Although none of the patients was obese at the time of diagnosis, three patients developed obesity after initiation of testosterone therapy.

Adolescent↗
PubMed1987

Adolescent self-reports of social activity: assessment of stability and relations to social adjustment.

Adolescents' self-reports of peer social activity were examined with regard to short-term stability and in relation to social adjustment. Two separate periods of data collection are reported; year 1 with 74 grade nine students and year 2 with 76 grade nine students. On both occasions, four administrations of a self-report questionnaire were undertaken. As well, in year 2, social adjustment ratings, indices of perceived competence and self-efficacy, and IQ were collected. The analyses of the measure's consistency indicated acceptable stability of the self reports across two weeks and high internal consistency. These findings indicate the potential utility of this methodology for studying peer activity. Zero-order and multiple correlation analyses between social activity, self-evaluations and social adjustment were computed. The analyses suggest that peer social activity is correlated with social self-esteem, enhanced social self-efficacy and teacher's ratings of social engagement. Social isolation appeared to be an independent dimension and was related to lowered self-esteem and teacher ratings of social withdrawal. Overall, the results of the study add to our understanding of the components of social adjustment in adolescence.

Adolescent↗
PubMed1986

Prostaglandins and cannabis XV. Comparison of enantiomeric cannabinoids in stimulating prostaglandin synthesis in fibroblasts.

Stereospecificity has been reported for a number of actions of the cannabinoids in a variety of systems. In the present report, we have shown that this effect can also be demonstrated when human lung fibroblasts in monolayer culture are stimulated by cannabinoids to produce prostaglandin E2 (PGE2). Three enantiomeric pairs of cannabinoids, (+) and (-)-delta 1-tetrahydrocannabinol (THC), (+) and (-)-delta 6-THC and (+) and (-)-delta 6-dimethylheptyl (DMH) THC were tested. In each case the (-) isomer was significantly more potent in agreement with the findings of others using different systems. Interestingly, very little stereospecificity was found in fibroblasts when the release of arachidonic acid, the precursor of PGE2, was monitored. This suggests that cannabinoids may act at several sites within the cell some of which show comparatively greater stereoselectivity for these agonists.

Arachidonic Acid↗
PubMed1986

Prostaglandins and cannabis--XVI. Antagonism of delta 1-tetrahydrocannabinol action by its metabolites.

Prior exposure of cells in vitro to delta 1-tetrahydrocannabinol-7-oic acid (delta 1-THC-7-oic acid) reduced the degree of stimulation of prostaglandin synthesis incurred by subsequent treatment with delta 1-THC. The site of action of this inhibitory effect seemed to be on cyclooxygenase and not at the earlier step involving the phospholipase-mediated release of arachidonic acid. delta 1-THC-7-oic acid is a major metabolite of delta 1-THC and has no psychoactivity in humans. Our findings raise the possibility, however, that it may influence the in vivo activities of delta 1-THC by antagonizing its stimulatory action on cellular prostaglandin synthesis.

Animals↗
PubMed1986

Effects of cannabinoids on the activities of mouse brain lipases.

Cannabinoids were found to augment phospholipase activities and modify lipid levels of mouse brain synaptosomes, myelin and mitochondria. Delta-1-tetra-hydrocannabinol (delta 1-THC) and several of its metabolites induced a dose-dependent (0.32-16 microM) stimulation of phospholipase A2 (PLA2) activity resulting in the increased release of free arachidonic acid from exogenous [1-14C]phosphatidylcholine (PC). The potencies of the cannabinoids in modulating PLA2 activity were approximately of the order: 7-OH-delta 1-THC greater than delta 1-THC greater than 7-oxo-delta 1-THC greater than delta 1-THC-7-oic acid = 6 alpha OH-delta 1-THC much greater than 6 beta-OH-delta 1-THC. The hydrolysis of phosphatidylinositol (PI) by synaptosomal phospholipase C (PLC) was enhanced significantly by delta 1-THC and promoted diacylglyceride levels by greater than 100 percent compared to control values. In contrast, arachidonate was the major product resulting from phospholipase activities of a 20,000 g pellet. Synaptosomal diacylglyceride lipase activity was inhibited by delta 1-THC. [1-14C]Arachidonic acid was readily incorporated into subcellular membrane phospholipids and after exposure to cannabinoids led to diminished phosphoglyceride levels and concomitant increases in released neutral lipid products. These data suggest that cannabinoids control phospholipid turnover and metabolism in mouse brain preparations by the activation of phospholipases and, through this mechanism, may exert some of their effects.

Animals↗
PubMed1986

Methionyl human growth hormone and oxandrolone in Turner syndrome: preliminary results of a prospective randomized trial.

Seventy girls with Turner syndrome, 4 to 12 years of age, were randomly assigned to receive either no treatment (control) or methionyl human growth hormone (0.125 mg/kg three times per week), oxandrolone (0.125 mg/kg/day), or combination hGH plus oxandrolone therapy. Baseline growth rates averaged 4.3 cm/yr, and all were within 2 SD of mean growth velocity for age in girls with Turner syndrome. Sixty-seven girls remained in the study for a minimum of 1 year. Growth rates and growth velocity (in standard deviations for age in girls with Turner syndrome) were control 3.8 cm/yr (-0.1 SD), hGH 6.6 cm/yr (+2.3 SD), oxandrolone 7.9 cm/yr (+3.7 SD), and combination therapy 9.8 cm/yr (+5.4 SD). Mean bone ages advanced 1.0 years (hGH), 1.3 years (oxandrolone), and 1.6 years (combination). However, median increments in height age/bone age (delta HA/delta BA) ratios ranged from 1.0 to 1.1 for treatment groups, compared with 0.8 for the controls. Predicted adult height by the method of Bayley-Pinneau increased 2.5 cm for hGH or oxandrolone alone, and 3.2 cm for combination treatment. These data indicate that both hGH and oxandrolone can significantly stimulate short-term skeletal growth in patients with Turner syndrome, and potentially increase final adult height.

Adolescent↗
PubMed1986

Granular cell tumor of the pancreas.

We report a rare granular cell tumor of the pancreas. We take this to be the second report of such a tumor in this location, and the first to be diagnosed before death. Endoscopy, angiography, and finally laparotomy were critical in establishing the diagnosis.

Female↗
PubMed1986

The rapid ovarian secretory response to pituitary stimulation by the gonadotropin-releasing hormone agonist nafarelin in sexual precocity.

We evaluated a GnRH agonist (GnRHa) as a potential single stimulus to both pituitary and ovarian secretion in 13 girls with true precocious puberty. We compared the GnRH agonist [6-D-(2-naphthyl)alanine]GnRH acetate (nafarelin, Syntex) administered as a single sc injection of 0.2 microgram/kg to GnRH infused iv in a dose of 2 micrograms/kg X h for 3 h and assessed the response of plasma steroid intermediates in estradiol (E2) biosynthesis. Although serum LH and FSH levels increased to similar peaks 3 h after commencing GnRH and nafarelin testing, they rose faster (P less than 0.01 at 1 h) and remained elevated longer (P less than 0.05 at 24 h) after nafarelin administration. At the third hour of testing with either agent, LH and FSH rose 8.8- and 3.4-fold, respectively (P less than 0.001 vs. baseline), whereas the rise in E2 was inconsistent and averaged only one third (P less than 0.02). However, plasma E2 increased later after nafarelin, but not after GnRH, rising from a baseline level of 30 +/- 6 (+/- SEM) to 115 +/- 13 pg/ml at 24 h (P less than 0.001). The least E2 response to nafarelin at this time was 150%. This rise is probably an underestimate of the maximum E2 rise, since a 6-fold response to nafarelin was found at 12 h in patients sampled then. Measurement of steroid intermediates from progesterone and 17 alpha-hydroxypregnenolone to E2 indicated that the response to nafarelin was typical of normal ovarian follicular secretion. That is, plasma levels of the intermediates in E2 biosynthesis rose less than 2-fold, and only the elevations in androstenedione, from 58 +/- 10 to 78 +/- 16 ng/dl (P less than 0.05), and estrone, from 14 +/- 3 to 38 +/- 7 pg/ml (P less than 0.02), at 24 h were significant. The greater effectiveness of nafarelin than GnRH in stimulating E2 secretion appears to be related to the more prolonged gonadotropin response. The magnitude, consistency, specificity, and rapidity of the gonadotropin and E2 responses to nafarelin indicate that this is a promising agent for rapidly testing pituitary and ovarian function simultaneously.

Child↗
PubMed1985

Echocardiographic evaluation after blunt trauma of the chest.

We studied by cross-sectional echocardiography 27 consecutive subjects with severe blunt trauma of the chest. Inadequate studies were obtained in 6 subjects (22%). Abnormal, unexpected findings were noted in 6 of the remaining 21 subjects (29%): moderate size pericardial effusion in 3 and focal ventricular dysfunction in 4. No patient with echocardiographic abnormality was suspected clinically of having heart damage. One of the 6 subjects with abnormal echocardiographic findings died from sudden asystole 6 days later. The remaining 5 patients had normal echocardiographic findings when studied 1 week after trauma. This study shows that, following blunt chest trauma, cross-sectional echocardiography can detect unsuspected myocardial and pericardial damage in an appreciable number of patients. Ultrasonic examination of the heart complements other investigations in establishing the diagnosis of heart damage and may help improve the care of patients with heart trauma.

Adolescent↗
PubMed1985

The changing ratio of bioactive to immunoreactive luteinizing hormone (LH) through puberty principally reflects changing LH radioimmunoassay dose-response characteristics.

The ratio (B/I) of bioactive to immunoreactive LH in plasma varies during pubertal maturation. To elucidate the basis for these changes, we compared the dose-response characteristics of LH standards to those of plasma LH before and after GnRH infusion in normal males at various pubertal stages and girls with Turner's syndrome. We used a human LH (hLH) RIA modified to optimize specificity for LH bioactivity by employing a hLH tracer maximally bioactive in the rat interstitial cell testosterone production (RICT) bioassay. The pituitary hLH standards LER-907, NHPP I-1, and NHPP I-2 were not parallel to one another in the RIA, but were parallel in the RICT. Their relative slopes in the RIA were 1:1.35:1.49, respectively. The B/I for immunoreactive LH in these standards were 1 (LER-907):3 (I-1):5 (I-2). Dose-response characteristics varied greatly by patient category in the RIA. In contrast to the RICT, in which plasma from all subject groups, except the prepubertal basal group, gave parallel dose-response slopes, the groups differed in the steepness of their plasma LH RIA dose-response curves in the following order: adult post-GnRH congruent to adult basal congruent to pubertal post-GnRH greater than pubertal basal congruent to prepubertal post-GnRH congruent to prepubertal basal greater than Turner's syndrome. Prepubertal basal samples most closely resembled LER-907 in dose-response characteristics, while adult samples were most similar to NHPP I-1 and I-2. These characteristics were not related to the absolute LH concentration. Although the RIA dose-response characteristics of plasma LH changed during puberty, the B/I of basal LH did not increase through puberty using the modified hLH RIA, although B/I still rose in GnRH-stimulated samples during puberty. Our data demonstrate that the principal cause of variability in B/I is the changing dose-response characteristics of plasma LH in the RIA. We suggest that the source of this variability is a change in the molecular characteristics of LH in different states of pubertal maturation and gonadal function. The results imply that better ways of assaying LH are needed.

Adolescent↗
PubMed1985

Prostaglandins and cannabis XIV. Tolerance to the stimulatory actions of cannabinoids on arachidonate metabolism.

The stimulation of prostaglandin E2 synthesis by delta 1-tetrahydrocannabinol in cultured cells is rapidly diminished by successive exposures to the drug at 24-hr intervals. Cannabidiol and cannabicyclol, two other constituents of cannabis, also displayed this in vitro tolerance effect. The phenomenon could, in addition, be observed by measuring the release of arachidonic acid from these cells, suggesting that the site of action of the cannabinoids is at one or more of the lipases that are believed to control prostaglandin synthesis under most conditions. Tolerance to cannabinoid action has been reported for a variety of in vivo parameters; thus, this in vitro system exhibits similar behavior and may, therefore, be a good model for studies on the molecular mechanisms involved in tetrahydrocannabinol action.

Arachidonic Acid↗