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Biomedical subjects

C Volta

Publications and source records attributed to C Volta.

16 recordsLinked to original sources

Congenital anorchia: natural history and treatment.

This paper discusses the definition, pathogenesis, diagnosis and treatment of congenital anorchia. It concludes that preparations containing esters of testosterone are preferable to synthetic derivatives for long-term treatment as they are metabolized in the same way as endogenous testosterone. In addition, it appears that recommended doses for replacement therapy are lower than previously suggested. An ideal formulation of testosterone for use in androgen replacement therapy is not currently available.

Adolescent

GH response to GHRH, insulin, clonidine and arginine after GHRH pretreatment in children.

To determine whether differences in the neuroendocrine control of GH are present between children and adult subjects, the GH response to GHRH (1 microgram/kg) (group 1), insulin-induced hypoglycemia (0.1 U/kg iv) (group 2), clonidine (150 micrograms/m2 po) (group 3) and iv arginine (0.5 g/kg in 30 min) (group 4) after GHRH pretreatment (1 microgram/kg) was studied in 26 short-stature normal children (mean age 10.2 years). The results were compared with historical data in adults. No differences were present among mean peak GH levels after the first and second stimuli in groups 1, 2 and 3, while in group 4 the GH response to arginine administration was lower than that obtained after the initial GHRH (0.43 +/- 0.04 vs 0.9 +/- 0.13 nmol/l). Moreover, comparing the GH peak values following the second stimulus, it appears that the greatest GH responses were elicited by GHRH (1.31 +/- 0.23 nmol/l) and clonidine (1.11 +/- 0.22 nmol/l), while the lowest was elicited by arginine (0.43 +/- 0.04 nmol/l). In adults, sequential GHRH administration leads to inhibition of the response of the somatotropes, probably mediated by an increase in hypothalamic somatostatin. Our results confirm that after GHRH prestimulation GHRH elicits a significant GH response suggesting that activation of the somatostatinergic tone is less effective in children. This hypothesis also explains the low GH response to arginine which acts selectively through somatostatin inhibition.

Adolescent

Effectiveness of growth-promoting therapies. Comparison among growth hormone, clonidine, and levodopa.

The ability of growth hormone, clonidine, and levodopa to stimulate growth was compared in short and slowly growing children randomly assigned to different treatment regimens for 6 months. There were 10 children in each group, and 10 additional subjects served as controls. Growth hormone improved mean height velocity, height velocity SD score, and height SD score. The mean height velocity and height velocity SD score were significantly increased by clonidine, while levodopa only enhanced the mean height velocity SD score of the treated children. Moreover, in nine patients (90%) receiving growth hormone, two (20%) receiving clonidine, and one (10%) receiving levodopa, the height velocity was raised by more than 2 cm/y. The increments in height velocity and height SD score were greatest in the growth hormone group. Clonidine induced an increase in height velocity significantly different from that in control children only. In the control group, there was a significant reduction of height SD score with time.

Body Height

A proposed multi-detector method for prompt 90Sr detection in post-accident environmental matrices.

Strontium-90 is of relevant biological importance among fission products released during a fission reactor accident. Rapid information on its concentration in environmental matrices is extremely valuable, yet this implies chemical separations and handling with a shift in daughter equilibrium and therefore the need to wait a sufficient time for the equilibrium to be reestablished. The work concerns a feasibility study of a multi-detector system for a prompt evaluation of the 90Sr activity or, at least, a prompt determination of its order of magnitude in the presence of other pure beta and beta-gamma emitters; their interferences are examined on the basis of the Chernobyl releases and their decay properties. The technique is based on a plastic scintillator beta detector and a guard ring of BGO counters which can be logically connected in coincidence and anticoincidence. The evaluations show that a few hours are sufficient to determine a specific activity comparable with the Maximum Permissible Concentration in air by sampling 10 m3.

Accidents

Pulsatile growth hormone release in Turner's syndrome and short normal children.

To determine whether the quantitative and qualitative aspects of GH secretion in girls with Turner's syndrome are similar to those of short-normal children we studied the 24-h GH secretion of 10 patients with Turner's syndrome and 9 short-normal children with comparable auxological features. GH profiles, obtained by 30-min sampling, were analysed by the Pulsar programme. The pulsatile GH release over the 24 h in Turner's syndrome was similar to that in normal children. However, when the GH release over the 12 day and night hours were separately analysed, only normal children showed a night-time increase in the sum of peak amplitudes. Moreover, patients with Turner's syndrome had significantly decreased number and frequency of peaks in the night-time compared with short children. In short-normal children but not in Turner's syndrome, height velocity was related to the 24-h integrated concentration of GH, area under the curve over zero-line and over baseline, sum of peak areas, and amplitudes. Night-time GH area over zero-line and over baseline, mean peak amplitude, height area, sum of peak area and amplitudes were positively correlated with height velocity in short children, whereas in Turner's syndrome height velocity was related to daytime parameters only. In conclusion, girls with Turner's syndrome have a discrete pattern of pulsatile GH release. However, the relation of GH secretion to growth in these patients, is uncertain.

Body Height

Evaluation of traditional filters for water purification in Burkina Faso.

Most tropical water springs are polluted with microbial agents such as faecal coliforms and streptococci, so for the present and the forseeable future, boreholes are considered to be the most appropriate system for reducing the bacterial contamination of water. However, from source to consumer, safe drinking water usually becomes polluted with faecal bacteria. This observation which calls into question the success of the International Drinking Water Supply and Sanitation Decade should stimulate efforts to provide a reliable means of water purification. The use of traditional filters prepared with sand, gravel and charcoal has been proposed but our results reveal that they give no guarantee for the purification of bacteria-polluted water.

Burkina Faso

Thyroid function tests in children with congenital hypothyroidism on L-thyroxine treatment.

The plasma levels of thyroxine (T4), triiodothyronine (T3), free T4 (FT4), free T3 (FT3), reverse T3 (rT3) and immunoradiometrically assayed thyrotropin (IRMA TSH) have been measured in 28 L-T4-treated children with congenital hypothyroidism as well as in a control group (group C). The patients were subdivided into 2 groups according to the nonsuppressed (group A) or suppressed (group B) TSH response to TSH-releasing hormone (TRH). Basal IRMA TSH correlated with the TSH increment after TRH and it was significantly lower in group B vs. groups A and C, while no difference was present between groups A and B in regard to T4, FT4 and rT3, all higher than in group C. FT3 levels were similar in the 3 groups. In children, as in adults, basal IRMA TSH seems to be a reliable index in monitoring overtreatment.

Adolescent

Adrenal steroid, cortisol, adrenocorticotropin, and beta-endorphin responses to human corticotropin-releasing hormone stimulation test in normal children and children with premature pubarche.

To determine whether CRH affects adrenal androgen, beta-endorphin (B-E), and ACTH secretion in normal children during sexual maturation, 17-hydroxyprogesterone (17-OHP), androstenedione (D4-A), dehydroepiandrosterone (DHEA), DHEA sulfate (DS), cortisol, B-E, and ACTH were measured after an iv injection of 1 microgram/kg human CRH. Children with premature pubarche were similarly analyzed to establish whether this condition is accompanied by altered hormonal responses to CRH. CRH produced consistent increases in ACTH, B-EP, and cortisol blood levels, which were comparable at all age intervals in all groups. 17-OHP increased after CRH injection, but its response linearly with age. D4-A levels were not influenced, while DHEA and DS levels were only partially influenced by CRH. The stimulated D4-A to 17-OHP ratio increased with sexual maturation, whereas ratios of cortisol to 17-OHP and D4-A to DHEA remained constant. Children with premature pubarche had hormonal responses similar in magnitude to those of prepubertal children of comparable age. In conclusion, an increase in 17,20-desmolase efficiency occurs with postnatal maturation after CRH challenge. Moreover, CRH does not appear to play an important role in premature pubarche.

17-alpha-Hydroxyprogesterone

Delayed puberty.

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Adolescent

[Application of solar disinfection to drinking water in tropical regions].

Since unsafe water elicits a broad spectrum of bacteriological, parasitological and virological diseases, purification of polluted drinking water has to be developed in tropical rural regions. Around 70% of rural wells and 7% of bore-holes contain water unsafe for human consumption. Water is also contaminated during transport and storage. Several techniques of purification have been recommended to protect drinking water. Recently, sterilisation in the U. V. or simply in the sun rays has been systematically tested. In tropical rural areas, solar disinfection has given questionable results. It affords no guarantee for the health of the consumer in contrast with other techniques as chlorination.

Communicable Disease Control

Opioid peptides do not modulate atrial natriuretic peptide or aldosterone release under basal conditions in man.

The effect of two analogues of [Met]-enkephalin, [D-Ala2,N-Phe4,Met(0)-ol5]-enkephalin and its guanyl derivative, on plasma concentrations of atrial natriuretic peptide (ANP) and serum aldosterone in six normal subjects was investigated. All subjects were given a 1 litre water load to inhibit vasopressin release. Both analogues, when injected i.v. at a dose of 100 micrograms, stimulated release of prolactin and GH and inhibited serum cortisol; there was no significant change in blood pressure, pulse rate or urine output. Neither plasma concentrations of ANP nor serum aldosterone levels changed significantly after injection of either analogue at a low or high dose. Naloxone, given i.v. as an 8 mg bolus, also failed to alter concentrations of either ANP or aldosterone, while it significantly stimulated the release of serum LH and cortisol. It was concluded that under basal conditions opiate receptors are unable to modulate plasma ANP or serum aldosterone concentrations.

Adult

Final height in a group of untreated children with constitutional growth delay.

We retrospectively evaluated the growth of 41 children with constitutional growth delay followed till adulthood and never treated with growth-promoting therapies. Final height has been correlated with prepubertal height, genetic target and height prediction calculated in both prepuberty and puberty. All patients showed a significant improvement of their height standard deviation score (HSDS) from prepuberty to adulthood, and the great majority of them achieved a final height above the 3rd percentile. Moreover, we found a good correlation between final height and both genetic target and height prediction, even if the latter overestimated final height in 25% of the patients. In conclusion, our data confirm that constitutional growth delay is a normal variant of growth. Therefore, caution should be paid in considering pharmacological treatment of this condition.

Adolescent

Blood pressure behaviour and control in Turner syndrome.

UNLABELLED: Adult Turner syndrome (TS) patients frequently present hypertension. To clarify the pathogenesis of this hypertension we examined the blood pressure (BP) behaviour and the renin-angiotensin-aldosterone system in 31 TS patients (2-22 years of age). BP levels were occasionally elevated in 47% of the subjects and constantly elevated in 23%. Most of the patients were on estrogen replacement therapy, but 26% of them presented with elevated levels since childhood. Supine and upright plasma renin activity (PRA) values were higher in TS compared to controls and more elevated in hypertensive TS than in the normotensive ones. At Captopril challenge TS showed different PRA responses regardless of the karyotype and clinical features. Patients on estrogen therapy, however, exhibited higher increments of PRA after Captopril. CONCLUSIONS: TS patients show high frequency of hypertension in pediatric age. Estrogen therapy is an outbreaking and worsening factor. An estrogen independent role of the renin-angiotensin-aldosterone system in the pathogenesis of TS hypertension is still uncertain.

Adolescent

[Evaluation of the pituitary reserve of gonadotropins and seminal function of the testis in subjects operated for cryptorchism].

76 patients (prepuberal, puberal and adults) who had undergone surgery for monolateral (35) or bilateral (41) cryptorchidism in childhood were studied. Testicular volume (76 cases), seminiferal function (18 cases) and pituitary gonadotropin reserve (51 cases) were evaluated. We obtained the following results: 1) the prepuberal patients had a normal testicular volume, while 70% of the puberal and adult patients had a mean testicular volume below normal levels. 2) 55.6% of the adults who underwent spermiogram had a pathological seminiferal function. 3) The number of patients whith exagerated gonadotropin response to GnRH-test increases with increasing puberal stage and reaches its highest significance after complete puberal development. These data confirm that: 1) the long permanence of one or both testis out of their natural position has a negative influence on their trophism; 2) the long-term prognosis of the tubular function of the testis after orchidopessis is poor in a high percentage of cases. 3) the endocrine anomalies which follow the early morphologic and functional changes of the cryptorchid testis are more easily detected during puberty as a reduced hypothalamic feedback of the gonadotropin secretion.

Adolescent