PubMed Health⌕ Search

Biomedical subjects

A Carrascosa

Publications and source records attributed to A Carrascosa.

65 records · Page 4Linked to original sources
PubMed1986

[Chronic delay of growth with normal response of growth hormone secretion to provocation stimuli for its liberation and decreased somatomedin activity: treatment with growth hormone over 6 months].

Four prepuberal children, two girls and two boys, aged 7 years 3 months to 11 years 6 months with chronic growth retardation were studied. Informed parental consent was obtained. Growth was followed for two years or more and was always less than P 3. Growth velocity during observation period was 4 cm/y or less. Gastrointestinal, hepatic, renal and thyroid functions were normal. Skeletal X-ray examination revealed no anomalies. karyotype in the two girls was 44XX. Growth hormone (GH) secretion was evaluated in all cases by two different test: exercise-propranolol and insulin-induced hypoglycemia. Peaks of GH secretion were 10 ng/ml or more. In three patients, GH secretion was also evaluated during first two hours of deep-sleep. GH peaks were 10, 4 and 13.4 ng/ml, respectively. Somatomedin activity (SA) measured in basal condition on two different days with six month interval was low (0.28-0.70 U/ml) and increased after seven daily doses of 2 mg of GH, in all patients (0.80-1.12 U/ml). All patients were treated with GH (2 mg/3 times/week), and growth velocity increased from 4 to 8.7, from 3.9 to 8.8, from 3 to 6.5 and from 3.2 to 6 cm/y, respectively. In conclusion, SA is of value in selection of patients with chronic growth retardation, who may benefit from long-term GH therapy.

Child↗
PubMed1985

Morphologic and metabolic development of human fetal epiphyseal chondrocytes in primary culture.

Primary chondrocyte culture was carried out after enzymatic digestion of femoral and tibial epiphyseal cartilage of human fetuses, collected with informed parental consent within 12 h postmortem. Chondrocytes were cultured in HAM F-12 medium with penicillin and 15% serum. Three types of serum were used: human placental cord serum (HPS), fetal calf serum, and human male adult serum. Chondrocytes cultured with HPS grew as monolayers, formed abundant colony groups with a highly metachromatic pericellular matrix, and floating round cells were observed in the culture medium. By the 10th day of culture the great majority of proteoglycans present in the culture medium were found as aggregates. Chondrocytes cultured with fetal calf serum or human male adult serum grew as monolayers, were polygonal in shape, and the pericellular matrix was far less developed than in HPS cultures. By the confluent phase of growth, only approximately a third of the proteoglycans present in the culture medium were found as aggregates. Chondrocytes cultured with HPS proliferated significantly more rapidly than those cultured with fetal calf serum or human male adult serum. The results suggest that certain, as yet unidentified, factors are present in sufficient amount in HPS to allow chondrocytes in culture to retain phenotypic morphological and biochemical characteristics. HPS also facilitates growth of human fetal epiphyseal chondrocytes in culture. Primary human fetal epiphyseal chondrocyte culture could be a suitable experimental tool for the in vitro study of biochemical characteristics of cartilage and factors involved in fetal cartilage metabolism.

Blood↗
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

Hypothalamo-hypophyseal-testicular function in prepubertal boys with acute lymphoblastic leukemia following chemotherapy and testicular radiotherapy.

Hypothalamo-hypophyseal-testicular function was studied in twenty-eight prepubertal boys with ALL in clinical and haematological remission. Eighteen were treated with combined systemic chemotherapy (24-36 months) and the other ten, who had testicular leukemic infiltrates, received chemotherapy (38-60 months) and testicular radiotherapy (2 000 rad). Plasma levels of LH and FSH were measured before and after stimulation with LHRH (100 micrograms i.v.) and plasma levels of testosterone before and after stimulation with hCG (1 500 IU/48 h/7 doses). In patients treated with chemotherapy alone, mean basal LH and FSH, mean responses to LHRH stimulation and mean testosterone levels after stimulation with hCG did not significantly differ from those of the controls. Five of these patients who had normal testosterone values after three doses of hCG had testosterone values below the normal range after seven doses. In patients treated with chemotherapy and testicular radiotherapy, mean basal FSH and mean responses to LHRH stimulation were significantly higher than those of the controls. Testosterone values after stimulation with hCG were low in three and very low in the other seven. In both groups of patients data from testicular biopsies were consistent with functional results. We conclude that chemotherapy causes slight testicular damage, but chemotherapy and testicular radiotherapy produce severe testicular damage in patients with testicular leukemic infiltrates.

Child↗
PubMed1984

Androgen metabolism by human fetal epiphyseal cartilage and its chondrocytes in primary culture.

Androgen metabolism by human epiphyseal cartilage and chondrocytes in primary culture was studied during fetal life. Testosterone (T) and androstendione (delta 4) were incubated with epiphyseal cartilage and with chondrocytes in Dulbecco's medium for 4, 12, and 24 h. Androstanedione, delta 4, dihydrotestosterone (DHT), and androstanediol were separated by bidimensional thin layer chromatography and delta 4, DHT, and T recrystallized in five different solvent systems. The results showed that delta 4 was transformed into androstanedione, DHT, and T whereas T was metabolized into delta 4 and 5 alpha-reduced androgens. In both systems (epiphyseal cartilage and chondrocytes) delta 4 was the principal metabolite produced from T. There were no major differences in the metabolic patterns of delta 4 and T between epiphyseal cartilage and chondrocytes according to sex nor gestational age (11-32 weeks). In conclusion, 5 alpha-reductase activity was found in chondrocytes from human fetuses of both sexes, but T was mainly transformed into delta 4.

Androgens↗
PubMed1980

[Somatomedin activity and growth hormone secretion in children with idiopathic growth retardation (author's transl)].

Somatomedin activity, as estimated by the porcine bioassay and GH response to stimulation were compared in prepubertal children with severe growth retardation and lack of evidence of pituitary dysfunction. Somatomedin activity was strongly correlated with growth rate. A group of patients had a low somatomedin activity in contrast with normal GH responsiveness. This appears to be a rather frequent situation and deserves further evaluation of the somatomedin system and a more critical approach of GH secretion.

Adolescent↗
PubMedDate not supplied

Anomalous costochondral cartilage in fetal anencephaly.

Anencephaly is a human fetal malformation with absence of brain and calvarium superior to the orbits. The consequent absence of hypothalamus provides a unique model for studying human development, and therefore skeletal growth, in the absence of hypothalamic hormones and their regulatory functions. To assess the influence of hypothalamic insufficiency on cartilage development, we studied costochondral cartilage sections from eight anencephalic fetuses (18-22 weeks old) and seven controls (16-22 weeks old) with pathologies not directly related to skeletal growth. We found a previously undescribed anomalous organization of the cartilage in the anencephalic. The proliferative chondrocytes showed a disordered appearance with an increased proliferative zonal length (156 +/- 28 microm in anencephalic fetuses vs. 103 +/- 14 microm in controls, p = 0.006) and a concomitant decrease in the maturing portion, where cells form ordered isogenic groups (58 +/- 13 microm in anencephalic fetuses vs. 93 +/- 19 microm in controls, p = 0.003). In addition, cell density was significantly decreased in the proliferating and maturing zones in the anencephalic cases (84 +/- 21 vs. 130 +/- 21 cells/40 microm(2) in proliferating zone; 53 +/- 8 vs. 94 +/- 8 in maturing portion, p < 0.005). These alterations in the developing cartilage of the anencephalic may contribute to the observed growth retardation in these fetuses and reflect modifications in pituitary hormones and growth factors resulting from reduction in hypothalamopituitary function.

Anencephaly↗
PubMedDate not supplied

Human studies on the biological actions of IGF-1. Evidence suggesting that human fetal and postnatal epiphyseal cartilage is a target tissue for IGF-1 action.

Recent data show that in humans IGF-1 has insulin-like anabolic and growth promoting effects. However, the plasma levels at which IGF-1 exerts these effects differ. IGF-1 plasma levels similar to those in normal children and adults have a growth promoting effect, but higher levels are necessary for IGF-1 to exert insulin-like anabolic effects, and hypoglycemia is a potential risk. Longitudinal bone growth results from the proliferation and differentiation of chondrocytes in epiphyseal cartilage. We present our data from cultured human epiphyseal chondrocytes, which suggest that epiphyseal cartilage may be a target tissue for IGF-1 action during human fetal and postnatal development.

Adult↗