Search PubMed⌕ Search

Biomedical subjects

R Rappaport

Publications and source records attributed to R Rappaport.

At least 109 records · Page 6Linked to original sources
PubMed1987

Treatment of central precocious puberty with an LHRH agonist (Buserelin): effect on growth and bone maturation after three years of treatment.

The LHRH analog Buserelin was used to treat 27 children (21 girls, 6 boys) with central precocious puberty. Nineteen patients had idiopathic precocious puberty and 8 had organic lesions (hamartoma, hydrocephalus or suprasellar arachnoid cyst). All patients received 20 or 30 micrograms/kg/day s.c. of Buserelin, and we obtained plasma E2 less than 20 pg/ml, vaginal maturation index less than 30 in girls or plasma testosterone less than 0.3 ng/ml in boys. The mean growth rate decreased from 9.3 +/- 0.5 to 4.6 +/- 1.3 cm/year after 3 years. The velocity of skeletal maturation decreased so that the final height prediction improved by a mean value of 1.6 SD. As the follow-up increases, this study confirms that LHRHa therapy is effective and potentially improves the final height of children presenting active and severe central precocious puberty.

Aging↗
PubMed1987

Evidence for a direct in vitro action of sex steroids on rabbit cartilage cells during skeletal growth: influence of age and sex.

A direct effect of sex steroid hormones on in vitro cartilage cell metabolism was demonstrated. Cells were derived from rabbit fetuses on day 20 of gestation, and from male and female rabbits aged from 2 to 80 days. Testosterone (T), dihydrotestosterone (DHT), or 17 beta-estradiol (E2) (10(-9) -10(-9) M) were added to primary culture of epiphyseal articular chondrocytes. They showed an age-dependent stimulatory effect on [35S]sulfate incorporation into newly synthesized proteoglycans. In cultured rabbit fetal cartilage cells, the maximum active concentration of T and DHT was 10(-9) M with a 40% stimulating effect over control values. E2 was even more active with 80% stimulating effect when added at 10(-8) M. Chondrocytes from animals aged up to 5 days responded poorly and those from animals aged 5-30 days not at all. The response of cells from older animals varied with animal age and sex. T and DHT stimulated chondrocytes from males aged 32-55 days and females aged 40-52 days to about the same extent. E2 stimulated cells from animals of the same ages, but the response of female-derived cells was twice that of male-derived cells. The stimulating effect was dose dependent from 10(-11) to 10(-8) M and maximal at 10(-9) M for T and DHT and at 10(-8) M for E2. Puromycin completely abolished the effect.

Aging↗
PubMed1987

Somatomedin-C and growth in children with precocious puberty: a study of the effect of the level of growth hormone secretion.

This study was undertaken to investigate the role of GH secretion in the pubertal increase in plasma somatomedin-C (Sm-C) concentrations and its relation to growth in children with true precocious puberty (PP) and normal or deficient GH secretion. We studied 37 children (9 boys and 28 girls), divided into 3 groups according to their pubertal stages and their peak stimulated plasma GH concentration. Group I (n = 20) contained patients with PP and normal GH secretion. In group II (n = 8), PP was accompanied by GH deficiency. Group III (n = 9) patients were GH deficient and prepubertal. The mean plasma Sm-C (RIA) levels in groups I and II were 2.01 +/- 0.17 (+/- SEM) and 0.59 +/- 0.21 U/mL, respectively (P less than 0.001), and it was 0.09 +/- 0.01 U/mL in group III (P less than 0.001 compared to group II). The higher mean plasma Sm-C level in group II compared to that in group III could be related to a significantly higher GH response to arginine-insulin stimulation (P less than 0.02), although this value was in the hypopituitary range. The mean growth rate in group II (6.8 +/- 0.9 cm/yr) was also much higher than the rate in group III (1.9 +/- 0.5 cm/yr; P less than 0.001) and only slightly lower than that in group I (90 +/- 0.8 cm/yr; P less than 0.05). These data indicate that plasma Sm-C values are closely correlated with even small changes in GH secretion. The observed growth rates could, in general, be linked to plasma GH and Sm-C levels, as modulated by sex steroids, in these patients with precocious puberty.

Adolescent↗
PubMed1987

[Treatment of central precocious puberty with an LHRH analog. Effect on growth and bone maturation after 2 years of treatment].

Eighteen children (15 girls and 3 boys) with true precocious puberty have been treated with an LHRH analogue (HOE 766, Buserelin suprefact) given subcutaneously during one (n = 11) or two (n = 7) years. Six of 18 children had organic precocious puberty, but their responses to therapy did not show any difference. A satisfactory suppression was achieved in 16 cases with plasma testosterone below 0.5 ng/ml (boys) or estradiol below 25 pg/ml and vaginal maturation index below 35 (girls). The mean annual height gain diminished from 9.5 +/- 0.8 cm during the control year to 7.7 +/- 0.7 cm and 5.1 +/- 0.7 cm during the first and second years of therapy respectively (p less than 0.05). Simultaneously, the mean bone age of 10.4 +/- 0.4 yr at onset of treatment, was 11.4 +/- 0.4 yr after one year and 11.8 +/- 0.3 yr after two years. These changes explain an average increase of predicted height of 5.7 cm after two years of treatment with the LHRH analogue. At least on the basis of these data with two years follow-up, this treatment seems satisfactory. We did not find anti-Buserelin antibodies in any of these patients.

Body Height↗
PubMed1987

[Craniopharyngioma in children. Endocrine evaluation and treatment. Apropos of 37 cases].

Endocrine function was studied in 37 children treated for craniopharyngioma by total (22 cases) or partial (12 cases) excision and complementary or isolated irradiation (9 cases). Height deficiency was the only revealing sign in only 20% of cases. Skull X-rays showed patent abnormalities at the first examination in 36 of 37 cases. Analysis of 24 children before and after surgery helps defining the part played by surgery in endocrine deficiencies: the frequency of thyroid and GH deficiencies is poorly changed after surgery as they are most often already present before surgery. On the other hand, the frequency of corticotropin and antidiuretic deficiencies is highly increased after surgery. Gonadotropic deficiency is almost constant after surgery. The final height is greater than 2 SD in 9 of the 14 patients whose growth is completed.

Adolescent↗
PubMed1986

Acromicric dysplasia.

We describe a new type of bone dysplasia, the "acromicric dysplasia," based on the study of six patients. This dysplasia is characterized clinically by mild facial anomalies, markedly shortened hands and feet, and growth retardation that is severe in most of cases. Roentgenograms of the hands are characteristic: the metacarpals and the phalanges are short and stubby, the proximal portion of the last four metacarpals are slightly pointed with an external notch on the 2nd metacarpal and an internal notch on the 5th metacarpal, similar to pseudo-epiphysis. The shape of the epiphysis and the metaphysis of the long bones is almost normal, except for a slight deformation of the femoral heads in some patients. No signs of visceral storage were found, which rules out geleophysic dwarfism. The histological, histochemical, and electron microscopical examination of the growth cartilage in two cases showed similar lesions: disorganization of the growth zone with islands of cells, some of them degenerated; abnormal organization of collagen forming thick rims around the cells and wide fibers in the interterritorial matrix; large accumulation of glycogen in most chondrocytes. Both sexes are affected; all patients are isolated cases from normal families.

Biopsy↗
PubMed1986

Establishment of the mechanism of cytokinesis in animal cells.

The division mechanism is fixed in the surface during anaphase or about 4 minutes before furrowing begins in cylindrical cells. Under experimental conditions, the minimum time that the mitotic apparatus must act upon the surface is about 1 minute. The stimulus period is followed by a latent period of 2-3 minutes. The time of furrow formation can be advanced or delayed by manipulating the surface and the mitotic apparatus. Since furrows can be elicited long after normal division would have been completed, it is suggested that the brevity of the normal interaction period is not a consequence of the constitution of the interactants. The component of the mitotic apparatus that establishes the furrow moves from the region of the mitotic axis to the surface at 6-8 microns/minute, The components of the mitotic apparatus that are essential for furrow establishment are confined to the achromatic regions. In spherical cells with large asters, the spindles are not required, although the spindle's ability to establish furrows in spherical cells can be demonstrated by changing the cell's geometry. In nonspherical cells with small asters, the spindle is probably the normal active agent. Although the ability of the mitotic apparatus to establish furrows can be diminished or abolished by measures that reduce its overall size, there are no decisive data concerning which of its ultrastructural components play essential roles in cytokinesis. The effect of changing the geometrical relation between the mitotic apparatus and the surface differs according to the region affected. Division can be blocked or impeded only by changing the relation between the equatorial surface and the mitotic apparatus. The ability of the mitotic apparatus to establish furrows is diminished by increasing the distance between the astral centers and also by increasing the distance between the mitotic axis and the equatorial surface. The cleavage block that results from reduction in size of the mitotic apparatus can be reversed only by decreasing the distance from the mitotic axis to the equatorial surface. Artificial constrictions imposed in other regions are ineffective. The normal distance relation between the astral centers and the equatorial and polar surfaces in spherical eggs is not required for division. Cleavage can occur when the dimensional relations are reversed. Both the surface and the mitotic apparatus can interact to establish furrows after exposure to measures that disrupt their normal organization. Single, isolated asters can cause furrow-like constrictions. Their immediate effect is to cause local contraction in nearby surface.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1986

Simple methods and devices for handling echinoderm eggs.

This article describes several simple methods and easily made devices that have proved useful in experimentation on echinoderm eggs. It may be that some of the suggestions will prove useful for teaching purposes as well as for research. Beyond providing detailed instructions for a few methods, it is just as important to stress that simple, direct methods can still yield valuable data in important areas of experimentation.

Animals↗
PubMed1986

Isolated growth hormone (GH) deficiency type 1A associated with a double deletion in the human GH gene cluster.

The gene deletions responsible for isolated GH deficiency type 1A were characterized by direct analysis of genomic DNA prepared from the leukocytes of two affected children. The probands had typical symptoms of severe isolated GH deficiency complicated by antibody development and growth arrest after human (h) GH treatment. DNA analysis using the restriction endonucleases Eco RI, Bam HI, and Hind III revealed that the restriction fragment containing the hGH-N gene was absent along with those bearing the human chorionic somatomammotropin (hCS)-A and -B and hGH-V sequences. A total of about 40 kilobases DNA were absent due to two separate deletions flanking the hCS-L gene. The two affected siblings are homozygous for this rearrangement of the hGH/hCS gene cluster, which could have been generated by homologous crossing over between two different chromosomes, one bearing one of the previously described deletions of the hGH-N gene, and one bearing a deletion of DNA containing the hCS-A, hCS-B, and hGH-V sequences. Alternatively, this abnormality could have been generated by a complex intrachromosomal rearrangement. The parents, who are consanguinous, have DNA restriction patterns consistent with heterozygosity for this double deletion. This type of deletional mutation is the first involving multiple deletion of the hGH and hCS gene cluster.

Adolescent↗
PubMed1986

Growth, growth hormone secretion and somatomedin C after cranial irradiation for acute lymphoblastic leukemia.

In a large group of 74 patients irradiated with 2400 rad for acute lymphoblastic leukemia an unusually high frequency of complete GH deficiency was observed (40%). Only 11 out of 46 prepubertal children had growth retardation and seven children received hGH treatment. On the contrary 11 other prepubertal cases had normal growth rates in spite of lack of response to AITT. Plasma SmC values were correlated with growth rates but were discrepant with GH responses to AITT in some cases. Because of this high frequency of GH dysregulation further growth at time of puberty should be carefully documented.

Body Height↗
PubMed1986

[Role of pelvic ultrasonography in the diagnosis, therapeutic indications and surveillance of central precocious puberty].

The use of pelvic ultrasonography was evaluated as a diagnostic and follow-up tool in girls with precocious puberty. Before treatment 23 of 33 patients with central precocious puberty presented an increased size of the uterus. In 10 cases with prepubertal size of the uterus, the precocious puberty was only beginning or of mild severity. During treatment with a LHRH analogue, changes in uterine size were slow in spite of a satisfactory and rapid control of estrogen secretion. At onset of treatment, transient ovarian cysts were seen in 2 patients. In our experience, pelvic ultrasonography did not provide significant information on the control of the disease by LHRH analogue therapy. Of 16 girls with presumed premature thelarche, 3 presented signs of estrogenic stimulation of the uterus. It remains a useful technique to rule out the presence of ovarian cysts or tumors at time of diagnosis.

Buserelin↗
PubMed1986

[HLA antigens and different clinical forms of 21-hydroxylase deficiency in the French population].

HLA associations with 21-OH deficiency were studied on respectively 109 and 60 congenital and late onset French index cases. Significant negative associations were found with antigens B8: congenital forms; B5, DR3: late onset. Significant positive associations were observed with A3, Bw47 (A3 Cw6 Bw47 DR7): congenital forms; B40: salt-wasting form; B5: simple virilizing form; Aw33, B14, DR1, DR2, DRw6 (Aw33 B14 DR1): late onset form. Among late onset patients not bearing B14 antigens significant positive associations were observed with B12 and B35.

Adrenal Hyperplasia, Congenital↗
PubMed1986

[Severe osteopenia in young children with hyperthyroidism. 2 cases].

The cases of 2 young children with Grave's disease and severe bone demineralization are reported. In one case, spontaneous fracture and a collapsed vertebra were noted. Increased serum alkaline phosphatase levels and normal 1.25-(OH)2D and 24-25 (OH)2D levels were observed when 25(OH)D levels were decreased. These anomalies, not described previously in young hyperthyroid children, should be kept in mind. Bone X-ray and calcium phosphorus metabolism investigations should be part of routine check-ups of young children with Grave's disease.

Calcium↗
PubMed1986

[Chemotherapy and ovarian function. Retrospective analysis in 17 girls treated for malignant tumor or hematologic disease].

Ovarian function was investigated in 17 patients aged 13 5/12 to 30 years who had received various types of combined chemotherapy without any irradiation. Ovarian insufficiency was found in 6 cases with amenorrhea (n = 5) or irregular menstruations (n = 1). There is a high risk of sterility in these cases although as described in one case, a normal pregnancy occurred in spite of evidence of ovarian failure. Cyclophosphamide seemed to be less harmful when given before puberty. Great variations in individual susceptibility for relatively low doses were observed with this drug. The combination with other drugs in some protocols might play a role in these cases. At variance with results reported in adults, the MOPP chemotherapy used in children with Hodgkin's disease did not induce ovarian dysfunction.

Adolescent↗