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Biomedical subjects

G Leboeuf

Publications and source records attributed to G Leboeuf.

At least 19 recordsLinked to original sources
PubMed1988

A twenty-year experience with thyroid carcinoma in children.

During the past 20 years, 23 patients (7 males, 16 females) were operated on for thyroid carcinoma in our institution. The average age was 13.6 years (range, 22 months to 27 years). Our series includes papillary carcinoma in 11, follicular carcinoma in four, and medullary thyroid carcinoma in eight patients. Follow-up ranged from 8 months to 20.3 years, with an average of 7.5 years for well-differentiated carcinomas and 4.3 years for medullary thyroid carcinomas. All patients are presently alive with no evidence of progressive disease. Patients with papillary and follicular carcinomas underwent partial thyroidectomy; those with medullary carcinoma underwent total thyroidectomy. Serious complications included three permanent hypoparathyroidism and two tracheostomies, all after secondary neck explorations. The overall results observed in our series of patients seem to support the current conservative approach to well-differentiated thyroid carcinoma, reserving total thyroidectomy for medullary cancer of the thyroid. A more aggressive search for familial medullary carcinoma through use of pentagastrin stimulation leads to early detection and more effective therapy.

Adenocarcinoma↗
PubMed1987

Extracellular correction of the androgen-receptor transformation defect in two families with complete androgen resistance.

We have characterized the cellular and extracellular phenotype of the mutant androgen receptor (AR) from two families who have complete androgen resistance despite a normal androgen-binding capacity (Bmax) in their genital skin fibroblasts (GSF). The cellular receptors fail to up-regulate their basal AR activity in response to prolonged incubation with 5 alpha-dihydrotestosterone (DHT), or with two synthetic androgens, methyltrienolone (MT) and mibolerone (MB), and form A-R complexes with increased equilibrium (Kd) and non-equilibrium (k) dissociation constants. In addition, they are thermolabile when recently dissociated, but not in their native state. A-R complexes made in normal or mutant cytosol at 4 degrees C elute from DEAE-Sephacel at approximately 0.25 M KCl (untransformed), with or without prior passage through Sephadex G-25; when made in cells at 37 degrees C, extracted with 0.4 M KCl in a buffer containing 10 mM Na2MoO4, and desalted by G-25, they elute at less than or equal to 0.1 M KCl. Normal KCl-extracted DHT- and MB-R complexes dissociate (37 degrees C) at the same slow, linear rate as their in-cell counterparts (transformed); the mutant ones dissociated more slowly than their rapidly-dissociating in-cell counterparts and, to a variable extent, nonlinearly-an early faster phase, a later slower (transformed). Thus, as judged by two conventional criteria of steroid-R complex transformation, the mutant A-R complexes can transform, possibly in two steps, under certain cell-free conditions. This behavior differentiates a class of structural AR mutations whose molecular definition awaits application of recombinant DNA techniques to the X-linked AR locus.

Androgens↗
PubMed1987

Management of thyroid nodules in children: a 20-year experience.

The medical records and surgical slides of 58 patients with the diagnosis of thyroid nodules (solitary nodule in 50 patients) are reviewed. The most common cause of thyroid nodules in this series is follicular adenoma (27 patients or 46%). A nuclear scan (technetium or radioactive iodine) was performed in 55 patients, of which 40 showed a cold nodule. Twelve of the 40 cold nodules were malignant (30%). However, for solitary nodules the incidence of cancer is 27%. This last figure is significantly greater than the one recently reported by Hung et al (18.5%). Available diagnostic methods are reviewed and the clinical management as derived from our experience is presented.

Adolescent↗
PubMed1985

Oral and dental development in X chromosome aneuploidy.

Though frequently noted, orofacial anomalies in poly X syndromes have been seldom reviewed. In a study of patients with an X chromosome aneuploidy (XXXXX, XXXX, XXXXY, XXXY) the following facial and dental defects were found to be characteristic features of these syndromes: mainly bifid uvula and macroglossia, enamel defects, dental taurodontism and abnormal roots. These observations are discussed in the light of the possible role of X-linked genes.

Adolescent↗
PubMed1979

[Treatment of hyperthyroidism in childhood and adolescence (author's transl)].

33 cases of hyperthyroidism have been treated at "L'Hôpital Sainte-Justine" of Montréal, during the period 1961-1974. Nearly all patients were submitted to medical treatment. 15 were cured with medical treatment only, and 18 had to be submitted to a subtotal thyroidectomy. These two groups are compared and show the clear advantage of surgery in the treatment of this disease. There was no major post-operative complication. Two patients became definitively hypothyroid. The mean follow-up is five years and six months.

Adolescent↗
PubMed1978

Reevaluation of levodopa-propranolol as a test of growth hormone reserve in children.

The growth hormone (GH) reserve of 15 short children was evaluated with the levodopa-propranolol test (DPT) and the sequential arginine-insulin test (AIT). Four patients failed to respond to both tests and were classified as hyposomatotropic. In the other 11 children, the mean GH peak response to the DPT was significantly higher than that to the AIT, mainly because five subjects who had a normal response to the DPT failed to respond to the AIT. These children had a generally poor yearly growth increment prior to testing associated in three with an obvious emotional problem, and were found at follow-up to have resumed a normal growth pattern. These data confirm the effectiveness of the DPT as a test of GH reserve. Although hypoglycemia can occur occasionally during test, this procedure is safer and easier to perform than the widely used AIT. Finally, the DPT seems to detect a category of children who have a temporary growth failure and nonresponse to the usual GH tests but who are not hyposomatotropic and consequently do not require human GH.

Adolescent↗
PubMed1977

Increase in plasma growth hormone levels following thyrotropin-releasing hormone injection in children with primary hypothyroidism.

Thyrotropin-releasing hormone (TRH) induced a significant increase in plasma growth hormone (GH) levels in 4 of 8 children with primary hypothyroidism, while a slight decrease was observed in 8 control children. Base-line plasma prolactin (PRL) levels and peak responses to TRH were higher in hypothyroid children than in controls. These data may indicate the existence of dysfunction of central nervous system mechanisms of control of GH and PRL secretion in subjects with primary hypothyroidism.

Adolescent↗
PubMed1975

Medical Research Council of Canada therapeutic trial of human growth hormone: first 5 years of therapy.

The Medical Research Council of Canada has initiated human growth hormone (hGH) therapy in 151 patients with documented complete hGH deficiency that was idiopathic in 76% of cases, secondary to craniopharyngioma (organic) in 17% and of varied cause in 7%. Approximately 50% of the patients with idiopathic disease had isolated hGH deficiency; during therapy thyroid deficiency developed in five patients and cortisol deficiency in three. A similar increase in mean height velocity occurred in the first treatment phase for patients less than 12 years old (0.93 plus or minus 0.30 cm/mo) and those 12 years and older (0.86 plus or minus 0.29 cm/mo). Although subsequent courses of hGH therapy yielded significantly diminished response in both age groups, this diminution was not progressive: the height velocity of the younger patients returned to 0.82 plus or minus 0.26 cm/ml in the fifth therapy phase. The mean height velocity attained at the optimal dosage (0.20 to 0.29 units/kg three times per week) for each age group did not differ significantly. Despite therapy being carried out for only 6 months of the year, normal increment ratios for height age and bone age against chronologic age were observed in the patients with idiopathic disease. In only four patients did treatment failure occur, and three of these were more than 20 years old. The addition of fluoxymesterone (10 mg/d) to the hGH therapeutic regimen (15 units/wk), when diminished response to hGH alone became evident, promoted an enhanced growth response in 9 of 11 older patients. These data indicate that age of the patient and dosage of hGH, but not diagnostic category, were important influences on the response to therapy. Younger patients responded best and maintained a higher mean growth velocity than older patients during intermittent hGH therapy

Adolescent↗
PubMed1975

Inhibition of pentobarbital-induced release of growth hormone by thyrotropin releasing hormone.

TRH antagonized the GH releasing effect of pentobarbital anesthesia as well in normal as in thyroidectomized rats, and significantly increased plasma B levels in normal animals. This effect was also observed when TRH was administered into a lateral ventricle of the brain in ug amounts, and was suppressed by the beta-adrenergic receptor blocker propranolol. T3 also antagonized the pentobarbital-induced release of GH; however, plasma B levels were not modified, and the effect on plasma GH levels was not suppressed by propranolol.

Animals↗
PubMed1975

Endocrine effects of chronic administration of psychoactive drugs to prepubertal male rats. II. LSD.

The endocrine effects of chronic D-lysergic acid diethylamide (LSD) administration to prepubertal animals were studied by injecting intraperitoneally three times a week for a month either 100 mug or 500 mug of the psychoactive drug per kilogram or the vehicle to groups of Sprague-Dawley male rats starting at 21 days of age. Animals injected with either dosage of LSD had smaller body weights than controls and tail length was significantly reduced in the high dosage group, plasma levels of growth hormone (GH) were decreased in the high dosage group, and pituitary levels in the low dosage group. Plasma levels and pituitary concentrations of luteinizing hormone and follicle stimulating hormone were not significantly modified by the drug. The low dosage of LSD decreased the brain levels of noradrenaline and increased those of dopamine, while the high dosage decreased those of 5-hydroxyindoleacetic acid. These data suggest that LSD, when administered chronically to developing animals, can inhibit body growth probably by altering the secretion of GH through modifications of its neuroendocrine control.

Animals↗
PubMed1975

Endocrine effects of pimozide, a specific dopaminergic blocker.

Pimozide, a specific blocker of dopaminergic receptors, was administered orally to 10 adult male volumteers for 4 days. Half of the subjects received 4 mg/day and the other half 2 mg/day. Blood samples were obtained the day before, the 4th day of Pimozide, and 4 days after the last dose of the drug for the determination of LH, FSH, GH, PRL, TSH, cortisol and testosterone levels. Twenty-four h urinary collections were obtained for the determination of LH and FSH levels. Plasma LH levels decreased and plasma PRL levels increased in the combined groups during Pimozide. Plasma TSH levels decreased during treatment in the 4 mg group only. Urinary LH and plasma testosterone levels decreased in the post-treatment period in the combined groups. These data support the concept of a dopaminergic control of the secretion of several hormones in the human.

Adult↗
PubMed1975

[Chronic hyperammonemia with orotic aciduria: evidence of pyrimidine pathway stimulation (author's transl)].

We have investigated a 3 year old girl with mental and physical retardation, chronic hyperammonemia and orotic aciduria. Plsma glutamine, alanine and proline concentrations were high. Alanine was present in her urine. She excreted only half the urea of control subjects on a similar protein intake. Raising protein intake induced NH4 intoxication with convulsion. Orotic aciduria was present (max: 693 mg/day) and was related to NH4 levels. Red blood cell orotate phosphoribosyl transferase and orotidine decarboxylase activieé were normal, eliminating congenital orotic aciduria, with induction of activity seen on repeated assay during protein load (form 1.37 to 7.5 nmole/109 RBC/hr). Blood ammonia rose with ornithine load, while ornithine levels were twice that of controls. Citrulline was normally metabolized. Although lacking liver assay, we have provided evidence of partial ornithine carbamyl transferase deficiency. The importance of orotic aciduria for ammonia detoxication in partial OCT deficiency is shown, and its possible effect on liver lipoprotein synthesis discussed. Our investigation also confirmed that OCT activity is not present in normal leukocytes rendering them useless for OCT deficiency diagnosis.

Alanine↗