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Biomedical subjects

R Rappaport

Publications and source records attributed to R Rappaport.

At least 127 records · Page 7Linked to original sources
PubMed1986

[Cushing's syndrome caused by multinodular adrenocortical dysplasia in a 3-year-old child. Association with a neurologic syndrome].

A case of multinodular pigmented adrenocortical hyperplasia occurring in a child aged 4 years is reported. The disease suggested an autonomously functioning lesion with low plasma ACTH. At surgery both adrenals presented with brown or yellow patches on the surface corresponding to multiple nodules. Unilateral adrenalectomy was followed by complete recovery and normal ACTH response to IV lysine vasopressin with a follow-up of 3 years. The patient also presented mild spastic diplegia and retarded mental development of unexplained origin.

Adrenal Cortex↗
PubMed1985

Repeated furrow formation from a single mitotic apparatus in cylindrical sand dollar eggs.

The methods used previously to demonstrate the ability of a single mitotic apparatus to elicit multiple furrows involved considerable cell distortion and did not permit the investigator to control the positioning of the parts or to observe satisfactorily the early stages of furrow development. In this investigation, Echinarachnius parma eggs were confined in 82 microns i.d. transparent, silicone rubber-walled capillaries, and the mitotic apparatus was moved by pushing the poles inward with 55-microns-diameter glass balls. When the mitotic apparatus was shifted immediately after the furrow first appeared, a new furrow appeared in the normal relation to the new position in 1-2 minutes. The same mitotic apparatus could elicit up to 13 furrows as it was shifted back and forth by alternately pushing in the poles. The previous furrow regressed as the new furrow developed. The operations protracted the furrow establishment period to as long as 24.5 minutes after establishment of the first furrow. The characteristics of furrow regression were related to the distance the mitotic apparatus was moved. It is unlikely that regression was caused either by stress imposed on the surface or the removal of the mitotic apparatus from the vicinity of the furrow.

Animals↗
PubMed1985

Diabetes insipidus in children. III. Anterior pituitary dysfunction in idiopathic types.

Seventeen patients with idiopathic diabetes insipidus occurring in childhood were observed from 4 to 26 years (mean duration 15 1/2 years). The diagnosis of idiopathic diabetes insipidus was based on routine clinical examination and careful, repeated neuroradiologic investigations. Anterior pituitary dysfunction was present in some of these patients. Growth hormone deficiency was present in six children, insufficient thyroid stimulating hormone secretion after thyrotropin-releasing hormone stimulation was demonstrated in one, and abnormal response to a metyrapone test in two. Elevated prolactin and TSH values were present in three and two patients, respectively. Some of these abnormalities were transitory. The presence of anterior pituitary dysfunction in idiopathic diabetes insipidus indicates that the destructive process is not localized to vasopressin synthesizing cells but may also involve other parts of the hypothalamus.

Adolescent↗
PubMed1985

An international survey of medical school programmes on nuclear war.

Many medical organizations have acknowledged the responsibility of doctors to educate health professionals and the public about the medical, social and ecological consequences of nuclear war. Medical schools have begun the development of programmes on these topics. A total of 1130 medical schools in thirty-one countries were surveyed about their presentation of nuclear-war-related subject matter. Eighty-three (49%) of the 168 schools that responded indicated that they offered an activity on medical aspects of nuclear war. Thirty-two per cent of the programmes consisted of one or more hours in an existing required course. Twelve per cent offered an elective course solely concerned with nuclear war. Although only 15% of the schools responded many of the replies indicated interest in learning more about the programmes of other schools and inquired if curriculum or teaching materials were available. Through the survey it was learned that textbooks and other learning resources have been prepared. Survey information suggests that knowledge of nuclear weapons effects is associated with a reluctance to countenance nuclear war.

Curriculum↗
PubMed1985

Long-term results of GnRH analogue (Buserelin) treatment in girls with central precocious puberty.

The GnRH analogue Buserelin was given for one year to six girls with central precocious puberty in a daily subcutaneous dose of 20 micrograms/kg/day. A decrease of plasma estradiol and vaginal maturation index to prepubertal values was obtained in 5 out of 6 cases. Bone maturation decreased and final predicted adult height improved significantly. This analogue of GnRH appears to be an effective medication for gonadotropin dependent precocious puberty in girls.

Buserelin↗
PubMed1985

Precocious puberty secondary to cranial irradiation for tumors distant from the hypothalamo-pituitary area.

This retrospective study is the first report of the occurrence of central precocious puberty in 6 children having received cranial irradiation. Pubertal development took place at a mean age of 7 5/12 years (6 10/12-7 10/12 years in 5 girls and at 9 years in 1 boy). They had received 2,400-4,500 rad at a mean age of 5 2/12 years. In addition, 5 children had GH deficiency so that their growth spurt was blunted and 3 of them were left with an extremely short stature. This condition would require a therapeutic approach combining the use of an LHRH analogue and hGH therapy when necessary in order to protect from too rapidly progressing bone maturation.

Adolescent↗
PubMed1985

[Statural growth following irradiation of the central nervous system for medulloblastoma of the posterior fossa. Retrospective analysis of 45 cases].

Treatment of medulloblastoma in children with head and spinal irradiation causes growth hormone deficiency and growth retardation. The present study deals with 45 patients presenting a follow-up time superior to 4 years; some of them having reached their final height. The mean final height is 3 standard deviations below normal mean. Growth retardation which occurred in 42 of 45 children, appears to be due to two major factors: 1) GH deficiency in 42 cases as assessed by the arginine insulin tolerance test. 2) Spinal lesions due to irradiation, causing early growth retardation and a reduced trunk length in most of these children. The response to hGH treatment (10 mg/kg/yr) was not sufficient in this group of patients.

Body Height↗
PubMed1985

[Results of treatment with human growth hormone in children with pituitary insufficiency under 7 years of age. Study of 26 cases].

Twenty-six children below age 7 years with idiopathic growth hormone deficiency have been treated with hGH for 2 years. Bone ages were inferior to 3 years and growth retardation averaged 3.9 +/- 0.9 standard deviation (SD) below the population mean. Results were compared to those obtained in a control group of 29 prepubertal patients, aged more than 7 years, and treated with hGH according to the same protocol. The mean height gains during the first and second year of treatment were respectively 8.4 +/- 1.8 cm and 6.6 +/- 1.5 cm. These values are significantly higher than those obtained in the group of older children. However within 2 years of treatment the initial catch-up in height of 0.9 +/- 0.6 DS was not different. In conclusion, we did not observe a better catch up growth in children before 7 years of age than in older prepubertal children, in spite of using higher doses of hGH.

Age Factors↗
PubMed1984

Division of constricted and urethane-treated sand dollar eggs: a test of the polar stimulation hypothesis.

In spherical cells with a central mitotic apparatus, the centers of the asters are closer to the poles than to the equator. This circumstance is basic to several hypothetical explanations of the way in which the mitotic apparatus establishes the division mechanism. This investigation was designed to determine whether that geometrical relationship is necessary for division. Fertilized, mechanically denuded sand dollar eggs were inserted into glass loops, which reduced the diameter in the constriction plane from the normal 142 to 78-80 microns and partly constricted the cell into equal parts. The mitotic apparatus straddled the constriction, and its length was not significantly changed. The manipulation increased the distance from the astral centers to the poles and decreased the distance from the astral centers to the equator to a degree that reversed the normal distance relations. These cells divided normally. Ethyl urethane (0.06 M) reduces the size of the mitotic apparatus and blocks cleavage in spherical cells. When treated cells are confined in 80-microns i.d. capillaries, they divide. Treated cells also divide when they are constricted by an 80-microns i.d. glass loop if the mitotic apparatus straddles the constriction. An equal degree of constriction in the subfurrow and subpolar areas did not reverse the effect of urethane. The results demonstrate that cleavage does not depend on the normal distance relation between the mitotic apparatus and the poles, and that the urethane effect can be remedied only by reducing the distance between the mitotic apparatus and the equatorial surface. Both findings are inconsistent with the polar stimulation hypothesis.

Animals↗
PubMed1984

Testosterone metabolism in prepubertal rabbit cartilage.

Using thin-layer chromatography, celite column chromatography and recrystallization methods, articular (AR) and growth plate (GP) cartilage tissues and cells from prepubertal rabbits were shown to convert testosterone (T) into at least three main metabolites: dihydrotestosterone (DHT), delta 4-androstenedione and androstanediols. In tissue incubation experiments the amount of each newly formed metabolite per mg of tissue was always greater in AR than in GP cartilage. After a 24 h incubation with AR or GP cartilage tissues, T was mainly converted to DHT and delta 4-androstenedione in approximately equal amounts. The amount of androstanediol metabolites formed was much lower. In a time-course experiment, the conversion of T to DHT and delta 4-androstenedione was shown to increase in a linear fashion, while the conversion to androstanediols was more variable. Using cultured AR cartilage cell incubations, similar results were obtained. In addition, DHT was shown to be the sole metabolite which accumulated in the cellular pool during the first 3 h incubation, as well as during the 24 h incubation when maximum cellular uptake of radioactivity was observed. At this time, the intracellular amount of unmetabolized [3H]T (88 pmoles/100 micrograms DNA) was similar to the amount of [3H]DHT (70 pmoles/100 micrograms DNA) accumulated in the chondrocytes. For both delta 4-androstenedione and androstanediols, 99% of radioactivity was extracted from the incubation medium.

Androstane-3,17-diol↗
PubMed1984

Twenty-four hour variations of thyroid hormones and thyrotrophin concentrations in hypothyroid infants treated with L-thyroxine.

The 24 hour plasma profile of T4, FT4, T3 and TSH was measured in a group of infants treated for congenital hypothyroidism with an oral aqueous preparation of L-T4 (5-7.5 micrograms/kg) given as a single dose at 0800 h. Mean basal plasma T4 was 8.4 +/- 2.0 micrograms/dl (mean +/- SD) and remained constant during the study while mean serum FT4 increased significantly from 1.64 +/- 0.50 ng/dl to a maximum of 2.08 +/- 0.63 ng/dl 4 h after medication. Plasma T3 decreased significantly from 241 +/- 48 ng/dl to 202 +/- 36 ng/dl 6 h after drug administration. Finally, plasma TSH decreased significantly from a mean of 24.2 +/- 18.8 microU/ml to 14.8 +/- 10.5 microU/ml 6 h later. Therefore during treatment of congenital hypothyroidism with L-T4 no specific schedule for T4 sampling is required. However, TSH determination 4 to 8 h after medication could slightly underestimate mean levels. In addition, any attempt to monitor treatment by FT4 determination should take into consideration variations of plasma values in the hours following L-T4 absorption.

Circadian Rhythm↗
PubMed1984

Incidence of anterior pituitary deficiency after radiotherapy at an early age: study in retinoblastoma.

Thirty-one patients treated for retinoblastoma in the first few years (3 months to 3 years and 6 months) of life were studied 2 to 15 years later. Radiotherapy delivered 1 300 to 6 500 rads to the hypothalamo-pituitary area. Growth deficiency was documented in 30% of all cases. Other pituitary deficiencies were the exception. The critical dose for GH insufficiency is between 2 000 and 3 000 rads, as in older children or adults. Our study does not support the hypothesis that the hypothalamo-pituitary area is more sensitive to radiation at an early age. Furthermore, conservative therapy of retinoblastoma leads to double lateral irradiation and will increase the number of GH deficient children after retinoblastoma.

Adolescent↗
PubMed1984

Germinoma in a boy with precocious puberty: evidence of hCG secretion by the tumoral cells.

The present report concerns a 10-year-old boy in whom diabetes insipidus and short stature were the first manifestations of a suprasellar germinoma. Neuroradiological investigations performed when these symptoms appeared were negative. 2 years later, a rapid and early pubertal development was observed and related to secretion by the germinoma of human chorionic gonadotropin (hCG) identified immunohistochemically. This clinical evolution is unusual and indicates that plasma hCG measurements in patients with so-called idiopathic diabetes insipidus can be of clinical value in predicting the presence of an hCG-secreting tumor.

Brain Neoplasms↗
PubMed1984

[Effect of hematologic treatment on the growth and puberty of children with thalassemia major].

This study reports on the endocrine abnormalities associated with delayed growth and puberty, observed in 10 children presenting with thalassemia major. Hormonal changes were followed up during treatment with regular transfusions and efficient chelating agents. Recovery of growth and onset of puberty were observed in most cases. When puberty was delayed, an associated substitutive treatment with sexual hormones was useful. In one case only, an isolated gonadotropic deficiency could be proven. In all cases STH, TSH and PRL secretions were normal. Without efficient and early treatment, the main consequence of the disease with respects to growth seems to be the risk of delayed puberty, mainly functional, or rarely hypogonadotropic due to definite LH and FSH deficiency.

Adolescent↗