Intensive dance practice. Repercussions on growth and puberty

To determine the effect of intensive sports training on growth and puberty, we studied a group of 97 young female dancers longitudinally for 5 years. We studied the changes in their heights, weights, and pubertal developments and compared these findings with those of a control group. We found that 15 (16%) dancers who started dance training had noticeably decreased growth velocity during the prepuberty stage after the beginning of ballet practice compared with the control group. This group had the same average training time compared with the other dancers, but these dancers were the slimmest and had the most inadequate nutritional intake. Puberty in dancers was delayed compared with the controls. We found that moderately intensive dance practice can lead to eating disorders and weight control early in childhood, with consequences that are poorly known. Weight and height statistics of children who practice individual sports involving body aesthetics must be monitored to detect early anomalies.

The role of calmodulin in the gravitropic response of the Arabidopsis thaliana agr-3 mutant

Calmodulin, a primary plant calcium receptor, is known to be intimately involved with gravitropic sensing and transduction. Using the calmodulin-binding inhibitors trifluoperazine, W7 and calmidazolium, gravitropic curvature of Arabidopsis thaliana (L.) Heynh, ecotype Landsberg, roots was separable into two phases. Phase I was detected at very low concentrations (0.01 microM) of trifluoperazine and calmidazolium, did not involve growth changes, accounted for about half the total curvature of the root and may represent the specific contribution of the cap to gravity sensing. Phase II commenced around 1.0 microM and involved inhibition of both growth and curvature. The agr-3 mutant exhibited a reduced gravitropic response and was found to lack phase I curvature, suggesting that the mutation alters either use or expression of calmodulin. The sequences of wild-type and agr-3 calmodulin (CaM-1) cDNAs, which are root specific were completely determined and found to be identical. Upon gravitropic stimulation, wild-type Arabidopsis seedlings increased calmodulin mRNA levels by threefold in 0.5 h. On the other hand, gravitropic stimulation of agr-3 decreased calmodulin mRNA accumulation. The possible basis of the two phases of curvature is discussed and it is concluded that agr-3 has a lesion located in a general gravity transmission sequence, present in many root cells, which involves calmodulin mRNA accumulation.

[Precocious puberty and polycystic ovarian syndrome: apropos of 13 cases]

BACKGROUND

Precocious puberty and polycystic ovarian syndrome are two different entities which appear at different stages of ovarian development. Their association is uncommon.

POPULATION

Thirteen girls presented idiopathic central precocious puberty with sexual development before the age of 8 years; menstruations were seen at the age of 9.5 years in one patient. Nine of them were given medroxyprogesterone or cyproterone acetate and two patients LHRH analog. Menarche occurred at a mean age of 11.8 +/- 1.5 years. After a mean free interval of 22 months, these thirteen patients developed hirsutism with irregular menstruations (eight patients) and weight gain (seven patients). The diagnosis of polycystic ovarian syndrome was confirmed by increased plasma testosterone (mean 91.1 +/- 14 ng/dl) and LH levels during LHRH test and by ultrasonography or coelioscopy. The treatment included cyproterone acetate plus 17 beta oestradiol; it was discontinued in eleven cases after 2 years of treatment. Plasma testosterone levels were normal 6 months later in association with regular menstruations. But three patients presented clinical and hormonal recurrence one year later, requiring repeated treatment.

CONCLUSION

This association seems to be related to the same gonadotropin dysfunction. It is necessary to regularly follow patients treated for precocious puberty.

Hairy function as a DNA-binding helix-loop-helix repressor of Drosophila sensory organ formation

Sensory organ formation in Drosophila is activated by proneural genes that encode basic-helix-loop-helix (bHLH) transcription factors. These genes are antagonized by hairy and other proline-bHLH proteins. hairy has not been shown to bind to DNA and has been proposed to form inactive heterodimers with proneural activator proteins. Here, we show that hairy does bind to DNA and has novel DNA-binding activity: hairy prefers a noncanonical site, CACGCG, although it also binds to related sites. Mutation of a single CACGCG site in the achaete (ac) proneural gene blocks hairy-mediated repression of ac transcription in cultured Drosophila cells. Moreover, the same CACGCG mutation in an ac minigene transformed into Drosophila creates ectopic sensory hair organs like those seen in hairy mutants. Together these results indicate that hairy represses sensory organ formation by directly repressing transcription of the ac proneural gene.

[Statistic study of 5,473 somatotropin secretion stimulation pharmacologic tests (n=9). Proposed weighting coefficient]

A total of 5,473 pharmacological provocative growth hormone release tests were carried out in 3,143 children. Mean age was 9 years 9 months (range 3-16 years) and mean bone age was 7 years 6 months (range 2-14 years). Tests were of 9 different types: 1) arginine (n = 625); 2) clonidine (n = 339); 3) insulin (n = 198); 4) ornithine (n = 162); 5) insulin + arginine (n = 203); 6) clonidine + betaxolol (n = 2,003); 7) L-dopa (n = 685); 8) glucagon = propranolol (n = 443); 9) glucagon + betaxolol (n = 815). All growth hormone determinations were performed using the same radioimmunoassay. Distribution of values obtained with each test was gausso-logarithmic. Mean peak levels with their 95% confidence limit were as follows: 1) 10.2 and 0.45; 2) 11.5 and 0.7; 3) 11.8 and 0.8; 4) 14.2 and 1.2; 5) 14.3 and 0.9; 6) 15.7 and 1.1; 7) 19.8 and 2.1; 8) 20.8 and 2.3; 9) 21.0 and 2.5. These data indicate low specificity, with up to two-fold differences in mean peak levels from one test to another; proportions of peaks under 10 ng/ml ranged from 29% to 69%. Thus, the rate of patients diagnosed with growth hormone deficiency may vary substantially according to the test used. To reduce these discrepancies, we suggest adjustment of test results using a weighting coefficient of 1) 1.9; 2) 1.48; 3) 1.4; 4) 1.16; 5) 1.06; 6) 1.01; 7) 0.73; 8) 0.69; 9) 0.66.

Inhibition of angiotensin converting enzyme with enalapril maleate in infants with congestive heart failure

We studied the inhibition of angiotensin converting enzyme (ACE) in eight infants with congestive heart failure (CHF) poorly controlled with digoxin and diuretics, treated orally with 0.25 mg kg-1 enalapril maleate once a day. Baseline ACE activities were compared between these infants and control children without CHF or ACE inhibitor. Except for one infant who vomited, inhibition of ACE activity was 75.5 +/- 12.2%, 75.5 +/- 10.5% and 51.7 +/- 12.2%, at 4, 12 and 24 h after drug intake respectively. There was no correlation between postnatal age and inhibition of ACE activity. In infants with CHF, mean baseline ACE activity was significantly higher than in control infants (36.4 +/- 7.2 mu ml-1 vs 26.9 +/- 6.9 mu ml-1, P < 0.05). These results were very similar to those seen in adults.

Investigation of the regulation of pigmentation in alpha-melanocyte-stimulating hormone responsive and unresponsive cultured B16 melanoma cells

In vitro melanocyte-stimulating hormone (MSH) stimulates melanogenesis in some, but not all, melanocytes and melanoma cells. In an attempt to explain this variation in response to alpha MSH, we examined cyclic adenosine monophosphate (cAMP) accumulation, tyrosinase activity, and melanin production in primary (1 degree) murine B16 melanoma cells and in two B16 cell lines (B16 F1 and B16 F10) that are known to respond to alpha MSH. In vivo all three B16 melanoma cell types produced pigmented tumours. In vitro alpha MSH increased tyrosinase activity and melanin content in the F1 and F10 cells but not in the B16 1 degree cells. alpha MSH, however, increased cAMP production in all three cell types, confirming that the inability of B16 1 degree cells to produce melanin in response to alpha MSH is not due to a lack of alpha MSH receptors or cAMP response to alpha MSH. Further, we present evidence for a separate pathway of melanogenesis that is independent of cAMP as calmodulin antagonists, which do not elevate cAMP, increased tyrosinase activity, and melanin production in both 1 degree and F1 cells.

Cytotoxicity of 4-hydroxyanisole and tyrosinase activity in variant cell lines of B16 melanoma

The melanocytotoxic effects of 4-hydroxyanisole (4-OHA) are thought to depend upon its conversion to toxic oxidation products by the enzyme tyrosinase. In this study, the cytotoxicity of 4-OHA was examined in different B16 melanoma cell lines that show varying levels of tyrosinase and after stimulation by melanocyte-stimulating hormone (MSH) and all-trans-retinoic acid (RA). 4-OHA decreased cell survival of three melanotic and one amelanotic cell line in culture, but the effect was unrelated to their tyrosinase activity or the subcellular localization of the enzyme. Although stimulation of tyrosinase activity with RA enhanced the cytotoxicity of 4-OHA, no similar enhancement occurred with alpha-MSH. It appears that there is no relationship between the cytotoxic effects of 4-OHA and intracellular tyrosinase and the enhancement of its cytotoxicity by RA may well be related to the antiproliferative effects of the retinoid.

Effect of PUVA on plasma and skin immunoreactive alpha-melanocyte stimulating hormone concentrations

Plasma alpha-melanocyte stimulating hormone (alpha-MSH) concentrations were measured in patients receiving PUVA therapy as treatment for mycosis fungoides, and PUVA or UVB as treatment for psoriasis. Skin immunoreactive alpha-MSH was also measured in those patients who received PUVA. The mean plasma and skin alpha-MSH concentrations after 2-3 weeks of PUVA were not significantly different from pre-treatment values and showed no relationship either to skin type or to the degree of tanning that occurred in response to PUVA. Plasma alpha-MSH concentrations were also unchanged after UVB. There was also no short term change in plasma alpha-MSH concentrations in patients after receiving their first treatment with PUVA. It would appear that circulating and skin alpha-MSH levels are unaffected by UV and show no causal relationship to PUVA induced pigmentation.

Band keratopathy due to hyperparathyroidism

A patient with hyperparathyroidism and corneal calcifications is reported. The calcifications appeared following phosphate treatment and persisted for 31/2 years, despite local instillation of EDTA. Local application of EDTA after mechanical removal of the corneal epithelium completely eliminated the corneal deposits.