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1.
J Acoust Soc Am ; 132(4): EL310-6, 2012 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-23039570

RESUMEN

Divers constitute a potential threat to waterside infrastructures. Active diver detection sonars are available commercially but present some shortcomings, particularly in highly reverberant environments. This has led to research on passive sonar for diver detection. Passive detection of open-circuit UBA (underwater breathing apparatus) has been demonstrated. This letter reports on the detection of a diver wearing closed-circuit UBA (rebreather) in an operational harbor. Beamforming is applied to a passive array of 10 hydrophones in a pseudo-random linear arrangement. Experimental results are presented demonstrating detection of the rebreather at ranges up to 120 m and are validated by GPS ground truth.


Asunto(s)
Acústica , Buceo , Equipo Deportivo , Agua , Acústica/instrumentación , Diseño de Equipo , Espiración , Sistemas de Información Geográfica , Humanos , Inhalación , Movimiento (Física) , Ruido , Reproducibilidad de los Resultados , Procesamiento de Señales Asistido por Computador , Espectrografía del Sonido , Factores de Tiempo , Transductores
2.
J Chromatogr A ; 1150(1-2): 162-72, 2007 May 25.
Artículo en Inglés | MEDLINE | ID: mdl-17222857

RESUMEN

This work describes a GC-MS method for enantioselective separation of amino acids. The method is based on a derivatization reaction which employs a mixture of alkyl chloroformate-alcohol-pyridine, as reagents to obtain the N(O,S)-alkyl alkoxy carbonyl esters of amino acids. Various reaction parameters are investigated and optimized to achieve a reproducible derivatization procedure suitable for separation of amino acid enantiomers on Chirasil-L-Val chiral stationary phase. In particular, the following topics are investigated for 20 proteinogenic amino acids: (i) the proper reagent and reaction conditions to obtain the highest derivative yield; (ii) the amino acid reactivity and the MS properties of the obtained derivatives; (iii) the linearity and sensitivity of the analytical method; (iv) the retention behavior of the derivatives and their enantiomeric separation on the Chirasil-L-Val chiral stationary phase. By combining the resolution power of the Chirasil-L-Val column and the high selectivity of the SIM MS detection mode, the described procedure enables the enantiomeric separation and quantification of 16 enantiomeric pairs of amino acids. The procedure is simple and fast and reproducible. It displays a wide linearity range at ppb detection limits for quantitative determinations: these properties make this derivatization method a suitable candidate for amino acid GC-MS analysis on board of the spacecrafts in space exploration missions of solar system body environments.


Asunto(s)
Aminoácidos/química , Formiatos/química , Cromatografía de Gases y Espectrometría de Masas/métodos , Aminoácidos/análisis , Estructura Molecular , Reproducibilidad de los Resultados , Estereoisomerismo
3.
Chirality ; 18(4): 279-95, 2006 May 05.
Artículo en Inglés | MEDLINE | ID: mdl-16534802

RESUMEN

The target of the in-situ research of optical activity in extraterrestrial samples stimulated an extended investigation of a GC-MS method based on the derivatization of amino acids by using a mixture of perfluorinated alcohols and perfluorinated anhydrides. Amino acids are converted to their N(O,S)-perfluoroacyl perfluoroalkyl esters in a single-step procedure, using different combinations of the derivatization reagents trifluoroacetic anhydride (TFAA)-2,2,2-trifluoro-1-ethanol (TFE), TFAA-2,2,3,3,4,4,4-heptafluoro-1-butanol (HFB), and heptafluorobutyric anhydride (HFBA)-HFB. The derivatives obtained are analyzed using two different chiral columns: Chirasil-L-Val and gamma-cyclodextrin (Rt-gamma-DEXsa) stationary phases which show different and complementary enantiomeric selectivity. The mass spectra of the derivatives are studied, and mass fragmentation patterns are proposed: significant fragment ions can be identified to detect amino acid derivatives. The obtained results are compared in terms of the enantiomeric separation achieved and mass spectrometric response. Linearity studies and the measurement of the limit of detection (LOD) show that the proposed method is suitable for a quantitative determination of enantiomers of several amino acids. The use of the programmed temperature vaporiser (PTV) technique for the injection of the untreated reaction mixture is a promising method for avoiding manual treatment of the sample and decreasing the LOD.


Asunto(s)
Aminoácidos/análisis , Vuelo Espacial , Acilación , Aminoácidos/química , Calibración , Esterificación , Ésteres/análisis , Ésteres/química , Cromatografía de Gases y Espectrometría de Masas , Estructura Molecular , Estándares de Referencia , Estereoisomerismo , Factores de Tiempo , Volatilización
4.
J Chromatogr A ; 1071(1-2): 255-61, 2005 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-15865201

RESUMEN

Gas chromatography-mass spectrometry (GC-MS) will be used in future space exploration missions, in order to seek organic molecules at the surface of Mars, and especially potential chemical indicators of life. Carboxylic acids are among the most expected organic species at the surface of Mars, and they could be numerous in the analysed samples. For this reason, a chemometric method was applied to support the interpretation of chromatograms of carboxylic acid mixtures. The method is based on AutoCovariance Function (ACVF) in order to extract information on the sample--number and chemical structure of the components--and on separation performance. The procedure was applied to standard samples containing targeted compounds which are among the most expected to be present in the Martian soil: n-alkanoic and benzene dicarboxylic acids. ACVF was computed on the obtained chromatograms and plotted versus retention time: peaks of the ACVF plot can be related to specific molecular structures and are diagnostic for chemical identification of compounds.


Asunto(s)
Exobiología , Cromatografía de Gases y Espectrometría de Masas/métodos , Marte , Suelo/análisis
5.
Thyroid ; 10(10): 859-63, 2000 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-11081252

RESUMEN

The de novo occurrence of germline-activating thyrotropin receptor (TSHR) gene mutations has been reported as the cause of sporadic nonautoimmune neonatal hyperthyroidism in eight children. We report the case of an Italian infant girl who presented at birth with severe hyperthyroidism and goiter. Ultrasonografic examination of the infant's thyroid showed a diffuse goiter with a normal echogenic pattern. Serum antithyroglobulin, antithyroperoxidase, and antithyrotropin receptor antibodies were undetectable. Treatment with propylthiouracyl, propranolol, and saturated potassium iodide solution started at 44 days of life with the resolution of thyrotoxic symptoms. Once euthyroidism was achieved, the dose of propylthiouracyl was tapered, but hyperthyroidism recurred. Auxological parameters showed an acceleration of linear growth and bone age. DNA was extracted from peripheral white blood cells of the patient, the sister, and the two parents. All of exon 10 of the TSHR gene was amplified by polymerase chain reaction (PCR) and subjected to direct sequencing. In the thyrotoxic infant girl, a substitution of cytosine to thymine was detected, changing isoleucine 568 into a threonine (1568T), located in the second extracellular loop. The normal sequence could also be detected, indicating heterozygosis of the mutated allele. This mutation was previously described as a somatic mutation in a patient with toxic thyroid adenoma. The sister and the parents of the propositus, all euthyroid, showed the wild-type TSHR gene. In conclusion, we describe a case of a de novo germinal mutation of the TSHR causing severe congenital hyperthyroidism.


Asunto(s)
Hipertiroidismo/congénito , Hipertiroidismo/genética , Mutación Puntual , Receptores de Tirotropina/genética , Adenoma/congénito , Adenoma/genética , Análisis Mutacional de ADN , Salud de la Familia , Femenino , Mutación de Línea Germinal , Bocio/congénito , Bocio/genética , Humanos , Hipertiroidismo/inmunología , Recién Nacido
7.
Arch Dis Child ; 78(2): 152-4, 1998 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-9579158

RESUMEN

Nineteen girls adopted from developing countries were referred for signs of idiopathic precocious puberty. After adoption, the catch up in linear and weight growth, together with improved nutritional and psychological conditions, may trigger the onset of puberty. Precocious puberty is a frequent and unnatural event in these girls. Treatment with gonadotrophin releasing analogues is indicated in patients diagnosed early, and when height prediction is poor.


Asunto(s)
Adopción , Países en Desarrollo , Pubertad Precoz , Análisis de Varianza , Estatura , Niño , Preescolar , Femenino , Humanos , Leuprolida/uso terapéutico , Fenómenos Fisiológicos de la Nutrición , Pubertad Precoz/tratamiento farmacológico , Pubertad Precoz/etiología , Pubertad Precoz/psicología
8.
J Clin Endocrinol Metab ; 82(7): 2283-8, 1997 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-9215308

RESUMEN

The fasting insulin resistance index, mean blood glucose, mean serum insulin (MSI), early insulin response to glucose, glucose uptake rate in peripheral tissues, and insulin sensitivity indexes in response to a standard oral glucose tolerance test; serum insulin-like growth factor I (IGF-I), IGF-binding protein-1 (IGFBP-1), IGFBP-3, and sex hormone binding-globulin (SHBG) levels; and the free androgen indexes were evaluated in 98 girls with premature pubarche [PP; prepubertal (B1; n = 32), early pubertal (B2; n = 27), midpubertal (B3; n = 23), and postmenarcheal (B5; n = 16)] and in 86 Tanner stage- and bone age-matched controls. We ascertained whether hyperinsulinemia is already present in PP girls before or during pubertal development and whether these patients show a similar pattern of growth factor secretion as normal girls. Body mass indexes did not differ significantly between patients and controls within the same pubertal stage. MSI levels showed a significant increase with pubertal onset in all subjects, as expected. Patients showed significantly higher MSI values than controls at all Tanner stages (P < 0.03, P = 0.03, P = 0.03, and P < 0.05 for B1, B2, B3, and B5, respectively); higher insulin response to glucose at B1, B2, and B3 (P < 0.03, P = 0.03, and P < 0.05, respectively); higher glucose uptake rate in peripheral tissues at B1 and B2 (P < 0.04 and P = 0.02, respectively); and a later rise in insulin sensitivity compared to controls. PP girls also showed lower IGFBP-1 levels at B1 and B5 (P < 0.01 and P = 0.02, respectively), lower SHBG concentrations at B5 (P < 0.0005), and higher free androgen indexes at B1, B3, and B5 (P < 0.01, P < 0.05, and P < 0.001, respectively) compared to controls. Among others, significant correlations between SHBG and MSI levels (r = -0.49; P < 0.0001) and between SHBG and IGFBP-1 levels (r = 0.41; P < 0.0001) were found in all subjects. Hyperinsulinemia, increased early insulin responses to glucose, increased glucose uptake rate in peripheral tissues, elevated free androgen indexes, and decreased SHBG and IGFBP-1 levels are present in most girls with PP from childhood. These findings lend strong support to the concept that PP is not a benign condition, and long term follow-up of these patients into adulthood is recommended. The possible causal role of hyperinsulinemia in adrenal and/or ovarian androgen hypersecretion remains to be established.


Asunto(s)
Hiperinsulinismo/sangre , Proteína 1 de Unión a Factor de Crecimiento Similar a la Insulina/sangre , Menarquia/sangre , Pubertad/sangre , Adolescente , Índice de Masa Corporal , Niño , Preescolar , Femenino , Humanos , Insulina/sangre , Proteína 3 de Unión a Factor de Crecimiento Similar a la Insulina/sangre , Factor I del Crecimiento Similar a la Insulina/análisis , Globulina de Unión a Hormona Sexual/análisis
9.
Eur J Endocrinol ; 136(6): 624-9, 1997 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-9225726

RESUMEN

OBJECTIVE: To investigate the pituitary-ovarian function in adolescent girls with insulin-dependent diabetes mellitus (IDDM). DESIGN: Clinical case-control study. METHODS: The GnRH analog leuprolide acetate was administered subcutaneously to 16 adolescents with IDDM (seven eumenorrheic and nine oligomenorrheic) and 13 controls between 0800 and 0900 h. Blood samples were collected at baseline and 0.5, 3, 6 and 24 h after leuprolide to measure levels of gonadotropins, 17 alpha-hydroxyprogesterone (17-OHP), androgens and estradiol. RESULTS: Mean baseline serum LH levels were significantly higher in eumenorrheic compared with oligomenorrheic IDDM patients, while peak LH responses to GnRH analog testing were similar in all subjects. Oligomenorrheic IDDM girls showed, as a group, a distinct 17-OHP response to GnRH analog stimulation, which in five out of nine girls was in the range of functional ovarian hyperandrogenism (> or = 8.6 nmol/l). Androgen and estradiol levels were not significantly altered in any group. No correlation was found between steroid levels and HbA1c levels, although the latter were significantly higher in oligomenorrheic than in eumenorrheic patients. CONCLUSION: About 50% of the oligomenorrheic IDDM adolescents had an increased ovarian 17-OHP response to GnRH analog stimulation in the range of functional ovarian hyperandrogenism. Factors other than metabolic control, such as stress, may play an etiologic role in IDDM ovarian dysfunction.


Asunto(s)
17-alfa-Hidroxiprogesterona/metabolismo , Diabetes Mellitus Tipo 1/complicaciones , Hormona Liberadora de Gonadotropina/análogos & derivados , Leuprolida , Oligomenorrea/etiología , Oligomenorrea/metabolismo , Ovario/metabolismo , 17-alfa-Hidroxiprogesterona/sangre , Adolescente , Adulto , Femenino , Humanos
10.
Fertil Steril ; 67(5): 849-55, 1997 May.
Artículo en Inglés | MEDLINE | ID: mdl-9130889

RESUMEN

OBJECTIVE: To assess the gonadotropin and ovarian steroid responses to the GnRH agonist (GnRH-a) leuprolide acetate (LA) in premature pubarche girls and in Tanner stage- and bone age-matched controls to ascertain whether the ovarian 17-hydroxyprogesterone (17-OHP) hyper-response to GnRH-a challenge present in some subsets of adolescent premature pubarche girls is detectable during puberty and whether these patients have a distinct pattern of pituitary-ovarian maturation. DESIGN: Cross-sectional study. SETTING: A university teaching hospital. PATIENT(S): Seventy-six premature pubarche girls (early pubertal [B2; n = 31], midpubertal [B3; n = 15], late pubertal [B4; n = 12], and postmenarcheal [B5; n = 18]) and 45 controls. INTERVENTION(S): Gonadotropins and plasma steroid hormones (17-OHP, 17-OH-pregnenolone [17-Preg], androstenedione [A], T, DHEA, DHEAS, E2, and cortisol) were measured before and 3 and 24 hours, respectively, after LA challenge (500 micrograms SC). MAIN OUTCOME MEASURE(S): Ovarian-steroidogenic responses to GnRH-a challenge. RESULT(S): Luteinizing hormone responsiveness increased significantly during puberty in all subjects whereas FSH levels changed less consistently. Peak E2 levels differed among pubertal stages and were significantly higher in premature pubarche girls than in controls at B4 and at B5. Both peak and incremental increases of 17-Preg and DHEA throughout puberty and of 17-OHP and A at B4 were significantly higher in premature pubarche girls than in controls. This pattern of ovarian-steroidogenic response was most evident during midpuberty and late puberty and resembled the adrenal hyper-response to ACTH of exaggerated adrenarche, suggestive of increased ovarian activity of both the 17 alpha-hydroxylase and the 17,20 lyase functions of cytochrome P450c17 alpha. CONCLUSION(S): Pubertal girls with a history of premature pubarche show a distinct pattern of ovarian maturation characterized by an exaggerated ovarian androgen synthesis throughout puberty.


Asunto(s)
Andrógenos/biosíntesis , Leuprolida , Ovario/metabolismo , Pubertad Precoz/metabolismo , 17-alfa-Hidroxipregnenolona/sangre , 17-alfa-Hidroxiprogesterona/sangre , Adolescente , Androstenodiona/sangre , Niño , Estudios Transversales , Deshidroepiandrosterona/sangre , Sulfato de Deshidroepiandrosterona/sangre , Estradiol/sangre , Femenino , Hormona Folículo Estimulante/sangre , Humanos , Hormona Luteinizante/sangre , Testosterona/sangre
11.
J Clin Endocrinol Metab ; 81(3): 1237-43, 1996 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-8772605

RESUMEN

Previous studies have documented the association of insulin resistance and hyperandrogenism in adult women with functional ovarian hyperandrogenism (FOH) or polycystic ovary syndrome (a form of FOH). However, the possible impact of adrenal hyperandrogenism development during childhood in premature pubarche (PP) patients on postpubertal insulin secretion patterns remains unclear. The fasting insulin to glucose ratio, C peptide, early insulin response to glucose (IRG), mean blood glucose, mean serum insulin (MSI), glucose uptake rate in peripheral tissues (M), and insulin sensitivity indexes (SI) in response to a standard oral glucose tolerance test were evaluated in 13 PP girls with FOH (group A; age, 17.2 +/- 0.5 yr), 11 eumenorrheic nonhirsute PP girls (group B; age, 16.6 +/- 0.5 yr), and 21 age-matched controls (group C). Body mass indexes (BMI) were similar in the 3 groups (group A, 23.3 +/- 0.8; group B, 22.5 +/- 0.6; group C, 20.6 +/- 0.5 kg/m2). MSI values were significantly higher in FOH patients than in controls (74.7 +/- 17.6 vs. 45.7 +/- 4.1 mU/L; P < 0.01), but were not different from those in group B (63.3 +/- 11.1 mU/L). Thirty-eight percent of FOH patients (group A) and 27% of non-FOH patients (group B), all of whom had normal BMI, showed MSI levels well above the upper normal limit for controls (> 83.3 mU/L). MSI correlated with the degree of ovarian hyperandrogenism [defined by an abnormal 17-hydroxyprogesterone response to challenge with the GnRH analog leuprolide acetate; group A] and with the free androgen index [testosterone (nanomoles per L)/sex hormone-binding globulin (nanomoles per L) x 100; groups A and B)]. Although IRG, glucose uptake rate in peripheral tissues, mean blood glucose, and SI values were not significantly different in the 3 groups, 3 patients in group A and 1 patient in group B showed decreased insulin sensitivity and/or an enhanced early IRG. Among others, significant correlations between MSI and free androgen index values (r = 0.6; P < 0.002; groups A and B) and between BMI and SI (r = -0.53; P < 0.05; groups A and B) were found. Peak 17-hydroxyprogesterone responses to ACTH at PP diagnosis correlated positively with SI in both groups of patients (r = 0.53; P < 0.007). Hyperinsulinemia is a common feature in adolescent PP patients with FOH and appears to be directly related to the degree of androgen excess. Long term follow-up of PP patients into adulthood is warranted to ascertain whether hyperinsulinemia actually precedes FOH development and whether overt insulin resistance ensues.


Asunto(s)
Cabello/crecimiento & desarrollo , Hiperandrogenismo/complicaciones , Hiperinsulinismo/complicaciones , Ovario/metabolismo , Pubertad/sangre , Maduración Sexual , Adolescente , Andrógenos/sangre , Glucemia/análisis , Péptido C/sangre , Femenino , Humanos , Hiperandrogenismo/metabolismo , Hiperinsulinismo/metabolismo , Insulina/sangre , Insulina/metabolismo , Secreción de Insulina , Registros Médicos
12.
J Clin Endocrinol Metab ; 81(2): 601-6, 1996 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-8636275

RESUMEN

To assess whether patients with congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency exhibit a steroidogenic response to GnRH agonist consistent with functional ovarian hyperandrogenism (FOH) and elucidate the relationship between adrenal and ovarian hyperandrogenism, the LH, FSH, estradiol, 17-hydroxyprogesterone (17-OHP), androstenedione, total testosterone, dehydroepiandrosterone, and 17-hydroxypregnenolone responses to a sc dose of leuprolide acetate (500 micrograms) were evaluated in 10 patients with classic CAH (mean age, 18.4 +/- 0.95 yr), 7 of whom had oligomenorrhea, pretreated with dexamethasone (2 mg/day for 5 days, including the day of the test). The results were compared with those obtained in 11 patients with FOH (mean age, 18.7 +/- 0.46 yr) and 17 normal women (mean age, 19.68 +/- 0.59 yr) not pretreated with dexamethasone. Leuprolide acetate stimulation caused a significant augmentation of plasma E2, 17-OHP, androstenedione, testosterone, and 17-hydroxypregnenolone concentrations in all CAH patients. However, in only 6 (60%) of them, all with oligomenorrhea, was the 17-OHP response (posttest minus pretest value) similar to that of FOH patients and significantly higher than that in controls. In this subset of CAH patients, LH plasma levels after stimulation were significantly higher than those of CAH subjects with 17-OHP responses in the normal range, controls, and FOH patients, whereas FSH levels were similar to those of controls. In this latter group, plasma FSH concentrations after stimulation were significantly higher than those in FOH. In conclusion, the results of the present study indicate that LH-dependent functional ovarian hyperandrogenism is frequent in patients with classic CAH. As ovarian hyperandrogenism might be partially responsible for the menstrual irregularities that are common complications in such patients, all classic CAH patients with oligomenorrhea should undergo short term stimulation with GnRH agonists to ascertain the presence of ovarian hyperandrogenism and receive appropriate treatment.


Asunto(s)
Hiperplasia Suprarrenal Congénita , Hiperplasia Suprarrenal Congénita/fisiopatología , Leuprolida , Ovario/fisiopatología , Hipófisis/fisiopatología , 17-alfa-Hidroxipregnenolona/sangre , 17-alfa-Hidroxiprogesterona , Adolescente , Hiperplasia Suprarrenal Congénita/enzimología , Adulto , Androstenodiona/sangre , Deshidroepiandrosterona/sangre , Estradiol/sangre , Femenino , Hormona Folículo Estimulante/sangre , Humanos , Hidroxiprogesteronas/sangre , Cinética , Hormona Luteinizante/sangre , Testosterona/sangre
13.
Horm Res ; 44(2): 51-6, 1995.
Artículo en Inglés | MEDLINE | ID: mdl-7590632

RESUMEN

Adrenal steroidogenic function was evaluated in 55 children with typical premature pubarche (PP) to investigate the incidence of late-onset congenital adrenal hyperplasia (LOCAH) due to 21-hydroxylase (21-OH) deficiency and to evaluate the usefulness of routine ACTH testing in these patients. Four patients fulfilled criteria for LOCAH due to 21-OH deficiency. Of these, 3 had elevated baseline 17-OHP levels; in the remainder, basal 17-OHP was within normal limits. Mean basal and stimulated 17-OHP responses in children with PP, excluding those with an enzymatic defect, were very similar to those of controls (2.3 +/- 1.8 vs. 1.6 +/- 0.9 and 10.0 +/- 4.0 vs. 9.5 +/- 3.3 nmol/l, respectively). However, 5 patients had basal 17-OHP values exceeding the upper limit of controls and 8 patients, including 2 of those with elevated baseline levels, showed supranormal poststimulated 17-OHP values. Body mass indices, height standard deviation scores (SDS) and bone age SDS showed no correlation with the basal or incremental rises of any hormone. Four (7%) of our population of patients with typical PP had LOCAH due to 21-OH deficiency. Basal 17-OHP levels were helpful in detecting altered steroidogenesis in 3, thus suggesting that in some PP patients, LOCAH due to this enzymatic defect may remain undiagnosed if ACTH stimulation test is not routinely performed.


Asunto(s)
Hiperplasia Suprarrenal Congénita , Hormona Adrenocorticotrópica , Pubertad Precoz/diagnóstico , Pubertad Precoz/enzimología , 17-alfa-Hidroxiprogesterona , Hiperplasia Suprarrenal Congénita/diagnóstico , Hiperplasia Suprarrenal Congénita/enzimología , Edad de Inicio , Niño , Preescolar , Deshidroepiandrosterona/sangre , Femenino , Humanos , Hidrocortisona/sangre , Hidroxiprogesteronas/sangre , Masculino
14.
J Clin Endocrinol Metab ; 79(6): 1778-84, 1994 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-7989484

RESUMEN

Functional ovarian hyperandrogenism (FOH) is characterized by an abnormal ovarian response to challenge with the GnRH analogs nafarelin and leuprolide acetate, similar to that observed in women with well defined polycystic ovary syndrome, regardless of whether elevated LH levels or polycystic ovaries are present. We studied an unselected group of 42 hyperandrogenic adolescents (age range, 14-22 yr; mean, 18.1 +/- 2.5 yr) 1) to determine FOH incidence through the assessment of ovarian-steroidogenic response to a single dose of leuprolide acetate, 2) to assess the clinical characteristics of patients according to their responses to GnRH analog stimulation, and 3) to evaluate adrenal steroidogenic function and its relation to ovarian hyperandrogenism in patients with either normal or abnormal responses to leuprolide acetate challenge. All patients underwent leuprolide acetate and ACTH testing, dexamethasone and ovarian suppression tests, and pelvic ultrasonography. Twenty-four (58%) patients had supranormal plasma 17-hydroxyprogesterone (17-OHP) responses to leuprolide acetate characteristic of FOH, and in 18, the 17-OHP response was similar to that of controls (n = 24; age, 17.1 +/- 2.3 yr). Seven patients (5 with FOH and 2 with normal responses to leuprolide acetate) had an abnormal response to ACTH, but only 1 had conclusive evidence of 21-hydroxylase deficiency. In 16 patients, the response to both stimulation tests was normal. Only 13 (54%) of the 24 FOH patients had polycystic ovaries on ultrasonography, and in 11 (46%), basal plasma LH levels were elevated. In FOH patients, reduction in testosterone and androstenedione plasma levels was significantly greater after ovarian suppression than after dexamethasone challenge (P < 0.0005 and P < 0.02, respectively). Peak plasma 17-OHP levels postleoprolide acetate simulation correlated with dexamethasone-suppressed plasma testosterone concentrations, dexamethasone-suppressed plasma androstenedione levels, and the free androgen index postdexamethasone treatment (r = 0.4, P = 0.01; r+ 0.4, P < 0.05; and r = 0.41, P = 0.007, respectively), Plasma sex hormone-binding globulin levels after dexamethasone administration correlated negatively with the baseline free androgen index (r = -.0.67; P < 0.0001). Considering our diagnostic criteria, 26 (62%) of our collective of 42 patients had abnormal responses to one or both stimulation tests, whereas 16 (37%) had normal response. FOH is the most common cause in (58%) of androgen excess in adolescence. Short term leuprolide acetate stimulation is a reliable tool fro identification of the ovary as the source of their hyperandrogenism.


Asunto(s)
Hiperandrogenismo/fisiopatología , Enfermedades del Ovario/fisiopatología , Ovario/fisiopatología , 17-alfa-Hidroxiprogesterona , Adolescente , Hormona Adrenocorticotrópica , Adulto , Androstenodiona/sangre , Dexametasona , Femenino , Humanos , Hidroxiprogesteronas/sangre , Hiperandrogenismo/diagnóstico por imagen , Leuprolida , Hormona Luteinizante/sangre , Enfermedades del Ovario/diagnóstico por imagen , Síndrome del Ovario Poliquístico/diagnóstico por imagen , Síndrome del Ovario Poliquístico/fisiopatología , Testosterona/sangre , Ultrasonografía
15.
J Hum Hypertens ; 8(5): 313-7, 1994 May.
Artículo en Inglés | MEDLINE | ID: mdl-8064775

RESUMEN

Hypertension, one of the most frequent and important complications of insulin-dependent diabetes mellitus (IDDM), usually begins in the second decade of the disease and is rare in childhood. We analysed the blood pressure (BP) levels of 106 patients (48 males, 58 females, aged 2-16 years) in relation to sex and age and we studied the modification of BP with years (tracking). BP levels, registered every three to six months, were compared with the local standard levels for age and expressed as standard deviation scores (SDS) of the means. For each subject a regression line describing the change of the SDS over time was calculated by the method of least squares. The slope of this line is called trend and represents the tendency of BP to increase or decrease with time, i.e. to develop (or not) hypertension. All patients, except one 16 year old girl, had normal BP and no microalbuminuria but ten of them presented with mean levels in the upper quartile and/or a constantly upward BP trend and were considered at risk. After a three year follow-up four of these ten patients became frankly hypertensive with increased microalbuminuria. These results agree with previous findings and with the hypothesis that an increase of intraglomerular and/or systemic BP may precede the appearance of (and even could be responsible for) microalbuminuria. The BP tracking study in IDDM children and adolescents could be useful for an early recognition of patients at risk of developing hypertension and diabetic nephropathy.


Asunto(s)
Presión Sanguínea , Diabetes Mellitus Tipo 1/fisiopatología , Envejecimiento/fisiología , Niño , Femenino , Humanos , Estudios Longitudinales , Masculino
16.
J Hum Hypertens ; 8(5): 395-7, 1994 May.
Artículo en Inglés | MEDLINE | ID: mdl-8064789

RESUMEN

Hypertension in neurofibromatosis is mostly a consequence of a stenosis of the renal artery or is due to phaeochromocytoma. Riccardi pointed out primary hypertension in patients with several cervical neurofibromas in the absence of phaeochromocytoma and he noticed that the elevation of BP was often already present in children. Nine (15.8%) of 57 neurofibromatosis patients (age from 1.5 to 23 years) examined, presented BP levels above the 95th percentile on several occasions and three in particular had severe hypertension with compromised target organs. Two of them had a stenosis of the renal artery, in the third an organic origin of hypertension was not demonstrated, but there was an asymptomatic glioma of the hypothalamus. The other six children had a labile or borderline hypertension and two of them had, respectively, a glioma of the thalamus and of the optical chiasm. Elevation of the catecholamine metabolites or other causes of hypertension were not found in any of these patients. These preliminary data show a high incidence of hypertension in neurofibromatosis, primary or due to organic causes and overall they point out a possible correlation between hypertension and cerebral neoplasia.


Asunto(s)
Hipertensión/etiología , Neurofibromatosis/complicaciones , Adolescente , Presión Sanguínea , Neoplasias Encefálicas/complicaciones , Niño , Preescolar , Femenino , Estudios de Seguimiento , Glioma/complicaciones , Humanos , Hipertensión/fisiopatología , Lactante , Masculino , Quiasma Óptico , Neoplasias del Sistema Nervioso Periférico/complicaciones , Obstrucción de la Arteria Renal/complicaciones , Enfermedades Talámicas/complicaciones
17.
J Clin Endocrinol Metab ; 78(1): 30-5, 1994 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-7507123

RESUMEN

The effects of a single injection (500 micrograms sc) of the GnRH agonist leuprolide acetate on gonadotropin secretion and those induced by a GnRH test were analyzed in 32 children (11 males and 21 females) referred for possible pubertal developmental disorders and in 9 prepubertal controls [group C; 4 males and 5 females; chronological age (CA), 7.4 +/- 1.2 yr]. The pituitary-gonadal secretory responses to the GnRH agonist were characterized in all subjects and in a control group in early puberty [10 females (Tanner breast stage II; CA, 11.3 +/- 1.1 yr) and 6 males (Tanner pubertal stage II; CA, 13.5 +/- 0.4 yr); group D]. Twelve girls (CA, 7.1 +/- 0.7 yr) presented with precocious breast development, 11 patients [6 boys (CA, 10.9 +/- 0.4 yr) and 5 girls (CA, 9.3 +/- 0.5 yr)] had advanced puberty and predicted adult heights below -2.0 SD score, and 9 patients [5 boys (CA, 14.6 +/- 0.3 yr) and 4 girls (CA, 14.4 +/- 1.1 yr)] had delayed puberty. Less than 6 months had elapsed since the appearance of pubertal signs in all patients with pubertal development. After a follow-up period of 12.9 +/- 2.0 months, 20 patients showed progression of pubertal signs (group A, progressive puberty), and in 12, puberty regressed or did not progress (group B, nonprogressive puberty). The results of hormonal tests in all patients were analyzed retrospectively according to their clinical outcome. Patients in group A had a mean plasma peak LH response significantly higher after leuprolide acetate stimulation than after GnRH challenge (13.1 +/- 0.2 vs. 7.3 +/- 0.9 IU/L; P < 0.003). Those in groups B and C had similar peak LH responses after both tests (3.3 +/- 0.2 vs. 3.1 +/- 0.4, and 1.5 +/- 0.1 vs. 1.8 +/- 0.4 IU/L, respectively). No differences in basal and poststimulated LH levels were found between boys and girls in the same group. In patients in groups A and D, LH consistently peaked 3 h postleuprolide acetate challenge; in those in groups B and C, the LH peak occurred 3-6 h postinjection. Maximal gonadal responses were elicited 24 h poststimulation. No overlap in poststimulated estradiol or testosterone values occurred between patients in groups A and D and those in groups B and C.(ABSTRACT TRUNCATED AT 400 WORDS)


Asunto(s)
Discapacidades del Desarrollo/diagnóstico , Hormona Liberadora de Gonadotropina , Leuprolida , Pubertad , Niño , Discapacidades del Desarrollo/diagnóstico por imagen , Estradiol/sangre , Femenino , Hormona Folículo Estimulante/sangre , Humanos , Hormona Luteinizante/sangre , Masculino , Testosterona/sangre , Ultrasonografía
18.
J Clin Endocrinol Metab ; 76(6): 1599-603, 1993 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-8501168

RESUMEN

The postpubertal outcome of a group of girls diagnosed of premature pubarche during childhood was assessed 1) to determine the incidence of functional ovarian hyperandrogenism (FOH) through the ovarian-steroidogenic response to the GnRH agonist leuprolide acetate, 2) to validate leuprolide acetate stimulation in FOH diagnosis, and 3) to ascertain whether FOH-predictive biochemical markers exist at the diagnosis of premature pubarche. Of 35 patients (age, 15.4 +/- 1.5 yr), 16 showed hirsutism, oligomenorrhea, and elevated baseline testosterone and/or androstenedione (delta 4-A) levels. Subcutaneous administration of leuprolide acetate (500 micrograms) produced similar increases in gonadotropin levels in oligomenorrheic patients, regularly menstruating patients (n = 19), and controls (n = 12; age, 15.3 +/- 1.3 yr) when tested at 6 h. Of all of the steroids measured, 17-hydroxyprogesterone (17-OHP) and delta 4-A levels 24 h postleuprolide acetate stimulation were significantly higher in oligomenorrheic patients than in the other two groups (P < 0.0001). No overlapping in 17-OHP responses occurred between oligomenorrheic patients and the other groups. Baseline dehydroepiandrosterone sulfate and delta 4-A levels at the diagnosis of premature pubarche correlated with 17-OHP values postleuprolide acetate challenge (r = 0.47; P < 0.005 and r = 0.67; P < 0.0001, respectively). These results show a distinct leuprolide acetate challenge response in 45% of the postpubertal premature pubarche girls studied, suggestive of an increased incidence of FOH, and support the need for continued routine postmenarcheal evaluation of this group of patients. Responses of 17-OHP to leuprolide acetate challenge facilitate the identification of FOH patients, establish this test as a reliable diagnostic tool in FOH diagnosis, and confirm the ovaries as the source of hyperandrogenemia in most patients with androgen excess. Although increased 17-OHP responses after leuprolide acetate stimulation seem to occur more frequently in girls with elevated dehydroepiandrosterone sulfate and/or delta 4-A levels at the diagnosis of premature pubarche, specific biochemical markers predictive of FOH in this group of patients are still lacking.


Asunto(s)
Andrógenos/sangre , Enfermedades del Ovario/epidemiología , Ovario/metabolismo , Pubertad Precoz/fisiopatología , Pubertad , Esteroides/biosíntesis , Femenino , Hormona Folículo Estimulante/sangre , Humanos , Incidencia , Leuprolida , Hormona Luteinizante/sangre , Enfermedades del Ovario/sangre , Enfermedades del Ovario/fisiopatología , Estudios Retrospectivos
19.
J Clin Endocrinol Metab ; 74(2): 254-7, 1992 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-1730803

RESUMEN

The natural history of girls with premature pubarche is reported to be normal, but the effects on puberty and on final height are not well documented. We assessed the outcome of a group of girls with premature pubarche from two Latin populations in whom 21-hydroxylase deficiency had been ruled out by an ACTH test. Patients comprised 127 girls (70 Northern-Italian and 57 Northern-Spanish), of whom 69 had entered puberty and 38 had attained adult height. Height, bone age, onset and progression of puberty, height prognosis, adult height, and baseline plasma androgen levels were evaluated. Advanced skeletal maturation and tall stature were constant features during the first years of follow-up and subsequently declined. Puberty began at 9.7 +/- 0.9 yr, and age at menarche (12.0 +/- 1.0 yr) was comparable to maternal and population menarcheal ages. The appearance and chronology of pubertal milestones in both populations were very similar. Adult heights correlated with the height prognosis at diagnosis and at onset of puberty, and were above midparental heights. Premature pubarche produces a transient acceleration in growth and bone maturation with no negative effects on the onset and progression of puberty and final height.


Asunto(s)
Enfermedades de la Corteza Suprarrenal/fisiopatología , Hiperfunción de las Glándulas Suprarrenales/fisiopatología , Pubertad , Adolescente , Factores de Edad , Estatura , Niño , Femenino , Humanos , Italia , Menarquia , Pronóstico
20.
Acta Biomed Ateneo Parmense ; 63(1-2): 187-92, 1992.
Artículo en Inglés | MEDLINE | ID: mdl-1340664

RESUMEN

One of the most frequent and important complications of IDDM is hypertension. It begins usually in adulthood and is rare in children. In order to study the behaviour and control of BP in IDDM children and adolescents we analyzed the BP levels of 106 patients (48 males, 58 females; age 1.5-16 yrs) in relation to sex, age, duration of the disease, and different parameters of metabolic control; moreover we studied the modifications of BP levels with years (tracking). BP levels, registered every 3-6 mos, were compared to the standard levels for age of the local population (2000 students between 7 and 16 yrs of age) and expressed as standard deviation scores (SDS) of the means. For each subject a line describing the change of the SDS over time was calculated by the method of least squares: the slope of this line is called trend and represents the tendency of the BP to increase or maintain stable or decrease with time, i.e to develop or not hypertension. All patients, except one 16 y. old girl, had normal BP and no microalbuminuria, but 10 of them presented with mean levels in the upper quartile and a constantly upward BP trend. Two of these patients showed after a 2 year follow-up stable hypertension and microalbuminuria. Moreover, an analytical and statistical study pointed out that BP levels of IDDM children seem to be influenced in addition to age, sex, height, weight, ponderal excess, as the general population, by the duration of the disease the insulin dose and some metabolic parameters (HbA1, HbA1c, glycemia, creatininemia).(ABSTRACT TRUNCATED AT 250 WORDS)


Asunto(s)
Presión Sanguínea/fisiología , Diabetes Mellitus Tipo 1/fisiopatología , Hipertensión/etiología , Adolescente , Factores de Edad , Niño , Preescolar , Diabetes Mellitus Tipo 1/complicaciones , Femenino , Humanos , Lactante , Masculino , Factores de Riesgo , Factores Sexuales
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