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Biomedical subjects

Z Laron

Publications and source records attributed to Z Laron.

At least 217 records · Page 12Linked to original sources
PubMed1984

The pattern of growth in children with constitutional tall stature from birth to age 9 years. A longitudinal study.

A study was made of the longitudinal growth pattern of 29 girls and 36 boys with constitutional tall stature (CTS) from birth to age 9 years. In these children, all of whom had a normal birth length, there was very rapid growth during the first 4 years of life, following which growth velocity dropped to normal and remained parallel to the 50th percentile. In the 49 subjects for whom actual final height was also obtained there was a very good agreement between this and the final height as predicted by Tanner's method from the height at ages 4 and 8 years. Significant differences were found between the mean maternal, paternal and mid-parental height and the tall stature of their offspring, but there was a very good correlation between the individual patients final height and their parental heights. The findings of this study stress the importance of periodical measurements of length and height in all children during the first few years of life so as to have appropriate data on which to base future considerations of possible therapy.

Body Height↗
PubMed1984

Premature thelarche--natural history and sex hormone secretion in 68 girls.

Data obtained during long-term follow-up of 68 girls with premature thelarche were analysed. In 85% onset was before the age of 2 years, in 30.8% being present at birth. In 44.1% there was a regression after 3 2/12 +/- 2 8/12 years (SD). Basal levels of plasma FSH and response to LH-RH were significantly higher than prepubertal controls (1.93 +/- 1.56 vs. 0.8 +/- 0.1 mU/ml and peaks 12.3 +/- 5.4 vs. 7.9 +/- 1.0 mU/ml respectively; p less than 0.001). Twenty-seven of 52 patients tested had increased plasma estradiol and in 27 of 40 patients tested, urocytograms or vaginal smear showed estrogenization. Basal levels of LH and response to LH-RH were prepubertal. The girls with premature thelarche were significantly taller than normal controls of the same age (p less than 0.001). These results suggest that premature thelarche is an incomplete form of precocious sexual development probably due to derangement in the maturation of the hypothalamo-pituitary-gonadal axis which results in a higher than normal secretion of FSH, as well as a defect in the peripheral sensitivity to the sex hormones.

17-Ketosteroids↗
PubMed1984

Basal plasma HGH and cortisol levels and the effect of clonidine administration in female migrainous patients.

Clonidine, a central alpha-adrenergic agent and prophylactic antimigraine drug is known to stimulate human growth hormone (HGH) release and to suppress cortisol secretion. A possible association between basal hormonal levels and response to either acute clonidine test or chronic treatment in female migrainous patients was investigated. 15 females, aged 18-43 years, suffering from migraine, underwent an acute clonidine test by administration of a single oral dose of 0.15 mg. High basal HGH levels (greater than or equal to 9 ng/ml) were observed in 6 patients, while the other 9 patients demonstrated normal low basal HGH levels. Acute clonidine administration induced a marked rise of HGH in 8 of the 9 patients with low basal HGH. In 4 of the 8 responders HGH levels exceeded 20 ng/ml and 3 subjects reached the acromegalic range (greater than 90 ng/ml). The mean response in this group was higher than in a reference group consisting of children and adolescents. It is suggested that the basal hypersecretion and the hyperresponsiveness of HGH to clonidine provocation test in some migrainous patients results from a hypersensitivity of the central alpha-adrenergic receptors. 12 of the 15 females were treated for 10 weeks with clonidine at gradually increased doses of 0.05 mg/day up to a maximal dose of 0.15 mg/day. A marked suppressive effect on cortisol secretion was observed in the migrainous patients after acute and chronic administration of clonidine. No correlation was observed between HGH and cortisol response to acute or chronic clonidine administration and the prophylactic effect of clonidine on migraine.

Adolescent↗
PubMed1984

Direct visualization of binding, aggregation and internalization of human growth hormone in cultured human lymphocytes.

The distribution of human growth hormone (hGH) receptor complexes on IM-9 cultured lymphocytes was studied using fluorescein and 125I-labelled hGH (F-hGH and [125I]hGH). The cells labelled with F-hGH were visualized with a sensitive video intensification microscopic system which permitted direct observation of the location of the fluorescent hormone on the surface of the living lymphocytes. At 4 degrees C F-hGH bound diffusely to the cell surface and remained dispersed but following incubation for 30 min at 37 degrees C the hormone receptor complexes aggregated into patches on the cell surface and formed a single cap on one pole of the cell. Progressive internalization into the cell was demonstrated at 37 degrees C with [125I]hGH. It is hypothesized that the aggregation and internalization of the hGH receptor complexes are associated with the action and degradation of the hormone and probably also with the mechanism of down-regulation of the receptors.

Cells, Cultured↗
PubMed1984

Defect of human growth hormone receptors in the liver of two patients with Laron-type dwarfism.

Liver microsome pellets prepared from tissue obtained by elective open biopsy from two patients (aged 4 and 26 years) with Laron-type dwarfism (LTD) showed no specific binding of 125I-hGH (human growth hormone). In contrast, 31 assays of liver microsomes obtained immediately after clinical death from 6 healthy subjects (kidney transplantation donors with a mean age of 24 years) showed a mean specific binding of 14% (range 7.9 to 24%). We interpreted these findings as evidence that in patients with LTD there is a defect in the hGH receptors of the liver and a consequent lack of somatomedin generation. The fact that the liver microsomes from the two LTD patients showed active specific binding of 125I-insulin suggest that, in this syndrome, it is only the receptors for hGH that are defective.

Adolescent↗
PubMed1984

Intellectual function of girls with precocious puberty.

The IQ of 52 girls with precocious puberty (mean age 9.5 +/- 2.8 years) was compared with that of 51 normal matched control subjects (mean age 9.7 +/- 2.8 years) and with that of eight girls with fast puberty (onset at normal age but accelerated advancement). Girls with precocious puberty had a significantly higher verbal IQ score than the control subjects but no difference was found in the performance score. The distribution of the verbal IQ score in the girls with precocious puberty was skewed toward the upper side of the theoretical distribution curve. The distribution was two or more times the expected theoretical percentile in the above average area (greater than 110, 56.9% v 25%), and five times more in the very superior area (greater than 130, 10.1% v 2.2%). The girls with fast puberty had the same behavior as the population with normal development. The results are interpreted as possible evidence of an effect of sex hormones on brain development, especially on the left hemisphere, during the prepubertal period.

Adolescent↗
PubMed1984

Unusual association of insulin-dependent diabetes mellitus with congenital myasthenia gravis and autoimmune thyroid disease.

A 26-year-old woman with congenital myasthenia gravis and antibodies to the acetylcholine receptor developed overt insulin-dependent diabetes with positive islet cell antibodies and thyroid microsomal and gastric parietal cell antibodies. Her younger sister has been an insulin-dependent diabetic since the age of 7 years, and the mother has nongoitrous hypothyroidism. In the same period the woman in question developed a transient chemical hyperthyroidism. HLA typing of the family members showed that the diabetes was probably associated with an HLA AW30, BW38, DR4 haplotype, found in both sisters and in their father, and that the thyroid disease was associated with the A29, B7, DR6 haplotype found in the patient and in her mother. This familial HLA pattern may indicate that each autoimmune manifestation in the patient is due to a different susceptible gene associated with the HLA system.

Adult↗
PubMed1984

Dietary adjustment during self-blood-glucose monitoring in pregnant women with insulin-dependent diabetes mellitus.

The interaction between the daily distribution of carbohydrates and frequent self-blood-glucose monitoring (SBGM) was studied in 13 pregnant women who had had diabetes for 4 to 19 years. Before and during SBGM, data were obtained on dietary history, daily blood glucose levels, and HbA1C. Optimal control was found with 3 main meals and 5 snacks. The total daily caloric intake decreased without change in the proportions of protein, fat, and carbohydrate. Consumption of starch increased, and that of simple sugars decreased. Although no changes were made in the daily amount of insulin, the women's diabetic control improved significantly.

Adult↗
PubMed1983

Residual B cell function in diabetic children as determined by urinary C-peptide.

C-peptide was determined in 24-h urine collections and in fasting plasma of 27 Type 1 (insulin-dependent) diabetic children (duration of disease 0-6 years) and in 11 matched normal children. Grouping the patients according to duration of disease from onset to 6 years, it was found that in the first year of disease the B cell reserve was a mean of 4.89 +/- 1.95 pmol X mg creatinine-1. 24 h-1 compared with a mean of 24.51 +/- 2.91 pmol X mg-1 X 24 h-1 in the control group. A further diminution was seen with increase in the duration of disease, until after 6 years when only traces of C-peptide could be detected. There was a good correlation between the levels of plasma C-peptide and urinary C-peptide values as related to creatinine (r = 0.89; p = less than 0.001). In view of this, and since it is simpler and less traumatic to obtain frequent urine samples from children than it is to obtain blood samples, it was felt that the determination of urinary C-peptide constitutes a valuable tool in the evaluation of the diabetic child.

Adolescent↗
PubMed1983

Evidence for a therapeutic effect of dl-propranolol in benign and malignant insulinoma: report of three cases.

Two patients suffering from benign and one patient suffering from malignant insulinoma experienced frequent incapacitating hypoglycemic attacks which did not respond to treatment with streptozotocin, diazoxide and/or diphenylhydantoin. Dl-propranolol, in dosages ranging from 30-240 mg/day, successfully abolished the symptoms of hypoglycemia, prevented recurrent hypoglycemic attacks, and normalized blood glucose levels concomitant with a reduction in pulse rate to 60/min. The main mechanism of the drug's effect seems to be the suppression of insulin release. However, other mechanisms may be involved such as increased peripheral insulin resistance. No side effects of treatment with dl-propranolol were noted. In patients suffering from insulinoma who are refractory to other forms of treatment, and for those who need symptomatic relief before surgery, dl-propranolol may play an important therapeutic role.

Adenoma, Islet Cell↗
PubMed1983

Human chorionic gonadotropin (hCG) treatment in cryptorchidism.

One hundred twenty-eight prepubertal boys, ages 1-12 years, were referred to our institute because of uni- or bilateral cryptorchidism. Patients with mobile (retractile) testes were not included in the study. They were treated with human chorionic gonadotrophin (hCG, Pregnyl-Teva) twice weekly for five consecutive weeks by the following doses; 1-4 years (n = 53) - 250 U X 10; 4-7 years (n = 51) - 500 U X 10; 7-12 years (n = 24) - 1000 U X 10;i.m. Plasma testosterone (T) levels were measured before and once weekly during the treatment period. A good clinical response (a complete descent of the testes into the scrotum) was obtained in 32 (25%), a partial response (a distal movement of the testes towards the scrotum) - in 41 (32%) of the boys. The basal plasma T levels were within the normal range for prepuberty in all the patients (18 +/- 9 ng/dl) and a significant increase during hCG treatment was found in all (peak of 344 +/- 185 to 640 +/- 288 ng/dl). These values were not significantly different between the "responders", "partial responders". The result of these studies, indicate the use of hCG for the initial treatment of boys with cryptorchidism, the minimal effective dose being 500 U twice weekly for five consecutive weeks.

Aging↗
PubMed1983

Diencephalic syndrome due to a suprasellar epidermoid cyst. Case report.

A 5-year-old child with the unusual association of late-onset diencephalic cachexia and pituitary insufficiency is described. At operation a suprasellar epidermoid cyst was found and excised. This curable tumor should be added in the differential diagnosis of diencephalic syndrome.

Brain Diseases↗
PubMed1983

Effect of chlorpromazine on hypothalamic-pituitary-gonadal function in 10 adolescent schizophrenic boys.

Low basal plasma testosterone levels with normal response to human chorionic gonadotropin (HCG) stimulation and mild hyperprolactinemia and blunted luteinizing hormone (LH) response to luteinizing-releasing hormone (LRH) stimulation were found in 10 adolescent schizophrenic boys who had been treated with chlorpromazine for more than 6 months. These findings may indicate a disturbance of the hypothalamic-pituitary-gonadal function in these patients, probably due to the prolonged administration of chlorpromazine. It remains to be established whether the decrease in basal testosterone secretion is caused directly by chlorpromazine or secondarily by the drug-induced hyperprolactinemia.

Adolescent↗