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Biomedical subjects

M Guibout

Publications and source records attributed to M Guibout.

At least 19 recordsLinked to original sources
PubMed2002

[Thyrotoxic hypokalemic periodic paralysis. Report of three cases].

AIM OF THIS STUDY: Hypokaliemic thyrotoxic periodic paralysis (HTPP) is an uncommon complication of hypothyroidism. Mostly described among Asian patients, it is rare in the other ethnic groups, in particular in caucasians people. Among the possible mechanisms, modification of potassic flows in relation to anomalies of the sodium-potassium pump were evoked. PATIENTS AND METHOD: We present the cases of three caucasians patients operated on for HTPP. These patients had all previous history of several paretic episodes. The flask paralytic attacks occurred in a brutal way or were preceded by diffuse myalgias. They reached the proximal muscles, especially in inferior limbs. No patient had any respiratory complications. These three patients underwent total thyroidectomy to treat the symptoms of HTPP. RESULTS: In the three cases, a total thyroidectomy allowed the recovery of the symptoms. After a four years average period of post-operative follow-up, no patient presented any repetition of HTPP. The hyperthyroidism is the cause of decompensation of the molecular anomaly. CONCLUSION: In our opinion, surgical treatment (total thyroidectomy) is needed in order to reduce the potential gravity of this pathology.

Adult↗
PubMed1992

[Pituitary tumor syndrome and hyperprolactinemia in peripheral hypothyroidism].

We studied 7 women with primary hypothyroidism who were suspected to harbor a prolactinoma on the basis of a pituitary gland enlargement associated with hyperprolactinemia. The diagnosis of prolactinoma was confirmed in 1 case only, which was treated surgically. In the remaining 6 patients the serum prolactin levels fell to normal on thyroxine replacement therapy and reduction in size of the pituitary gland was demonstrated by neuroradiological imaging in the 3 documented cases. This study underlines the fact that hyperprolactinemia associated with pituitary hyperplasia is secondary to hypothyroidism and that thyroid function tests should be obtained in all hyperprolactinemic patients even those with pituitary enlargement.

Adult↗
PubMed1986

Thyroid-stimulating hormone pituitary adenomas and hyperthyroidism.

Six cases of hyperthyroidism secondary to thyroid-stimulating hormone (TSH)-hypersecreting pituitary adenomas are presented (five females and one male). Hyperthyroidism presenting with diffuse goiter was associated with hyperprolactinemia in three cases. Elevation of triiodothyronine (T3) and thyroxine (T4) plasma levels was associated with TSH levels ranging between 2 and 2,000 microU/mL. Polytomography and computed tomography scanning with coronal views revealed four invasive and two enclosed tumors. Two patients underwent transfrontal operations, four underwent transsphenoidal operations, and one underwent both. Two cases of enclosed adenoma were cured primarily by a transsphenoidal approach without additional pituitary deficit. In four cases of invasive adenomas, operations and radiation therapy resulted in three failures and one cure. In cases presenting with hyperthyroidism and detectable TSH, early neuroradiological studies are indicated, as biological cure can be achieved by the transsphenoidal approach. Early treatment is also advocated because of the tendency for these tumors to become invasive (four out of six tumors).

Adenoma↗
PubMed1985

Transsphenoidal surgery for acromegaly--long-term results in 100 patients.

A series of 100 patients with acromegaly who were operated on using the transsphenoidal microsurgical approach is presented along with a review of the literature. Emphasis is placed on long-term follow-up to assess the value of the technique. The authors caution against early normalization of growth hormone as a criterion for biologic cure in that cases of late recurrence are presented. It is proposed that 5 ng/mL baseline growth hormone values with normal dynamic testing is the most reliable way to ascertain biologic cure. Using these criteria, a cure rate of 78% for enclosed and 33% for invasive adenomata was obtained. No long-term recurrence was seen in patients considered cured along these lines.

Acromegaly↗
PubMed1984

Suprasellar hemangioblastoma.

A case of suprasellar hemangioblastoma attached to the pituitary stalk is reviewed. The patient presented with amenorrhea-galactorrhea and a highly vascularized suprasellar lesion. Though the exact diagnosis was not made before the operation, the authors emphasize the importance of angiography, which had significant features regarding the diagnosis.

Adult↗
PubMed1984

[Neuroendocrine sarcoidosis: a case].

The authors report a case of neuro-endocrine sarcoidosis, associating panhypopituitarism , diabetes insipidus, and involvement of the optic chiasma with behavioural changes, chronic meningitis and a diffuse pyramidal syndrome. The diagnosis was suggested by the presence of mediastinal lymphadenopathy and confirmed during a surgical procedure to conserve the optic nerves. The clinical course on corticosteroids was unfavourable because of iatrogenic cushing' syndrome and steroid dependence . It was not possible to withdraw steroids, even with the use of immunosuppressors (Methotrexate).

Adrenal Cortex Hormones↗
PubMed1983

Intrasellar meningioma.

Two purely subdiaphragmatic intrasellar meningiomias are described. The rarity of this unusual intrasellar tumor is stressed, and the differential diagnosis of intrasellar meningioma versus pituitary adenoma is discussed. The good results of the rhinoseptal route for surgery are emphasized.

Adenoma↗
PubMed1980

[Lipocorticotropic peptides in Cushing's disease: in vitro studies].

The immunologic patterns of 3 human pituitary adenomas of Cushing's disease have been studied after gel exclusion chromatography (Sephadex G-50). The immunologic characteristics were examined with three radioimmunoassays specific for human corticotropin (ACTH), lipotropin (LPH) and beta-endorphin (beta-End). In cell tumor extracts, chromatographic peaks corresponding to beta-LPH, gamma-LPH, beta-End and ACTH were identified. The ACTH/beta-LP-beta-End ratio was 1 in the 3 cases. Additionally, in the 3 cases, a chromatographic peak, partially cross-reacting in the beta-End assay, was eluted after beta-End, thus suggesting the presence of a fragment of the molecule. In 1 case, a peak of large molecular weight material with N- and C-terminal beta-LPH and ACTH immunoreactivity was observed, which corresponded to the precursor material. The release and the effects of various stimuli were studied on dispersed tumor cells in primary culture. The tumor cells had a biphasic basal secretion rate with a rapid increase of ACTH/beta-LPH-beta-End in the culture medium during the first 2 h. Then the release, studied during 2 days, was slower. Chromatographic studies showed that the beta-LPH/beta-End ratio was 0.8 in the cells and 0.3 in the medium, due essentially to the release of beta-End and beta-End-like materials. The cells released ACTH and beta-LPH-beta-End in equimolar ratio after stimulation with arginine vasopressin (AVP). The maximum effect was obtained with 10(-6) M AVP (D50 = 1 10(-9) M). Dibutyryl cyclic AMP (2. 10(-3) M) induced maximal release of ACTH/beta-LPH-beta-End. This stimulation was suppressed by a 48-hour preincubation with dexamethasone (10(-8)-10(-6) M). There was no effect of TRH and LH-RH on cell release. Dopamine (10(-6) M) specifically blocked the release of ACTH/beta-LPH-beta-End in 1 case. These data showed (a) heterogeneity of chromatographic profiles from case to case; (b) the presence of material in the tumor, cell extracts and culture medium corresponding to fragment(s) of beta-End; (c) culture studies demonstrated that tumor cells remain responsive to AVP stimulation and dexamethasone suppression, and (d) the dopamine inhibition of ACTH and beta-End release needs further investigation.

Adenoma↗
PubMed1980

Prolactin secreting adenoma in 22 men.

The authors report on 22 men with a prolactin secreting adenoma. Clinical symptomatology included associated signs of tumoral compression with varying degrees of hypogonadism. Endocrinological evaluation disclosed hyperprolactinemia in all cases but one, and hypopituitarism in 10 of 22 cases. Of the 22 patients, 21 underwent transsphenoidal microsurgery (two of whom underwent a second procedure by the infrafrontal approach) and in one case surgery was performed by the infrafrontal route. Diagnosis was confirmed by immunocytochemical evaluation of tumoral tissue. Prolactin levels returned to normal in 32% of cases after operation and became normal after complementary bromocriptine therapy in 54.5% of cases. However, normal prolactin secretion was not consistently accompanied by a return to normal of gonadotropin regulation. In three patients radiotherapy was not effective. The latter treatment should be limited to the very rare cases of postoperative resistance to bromocriptine.

Adenoma↗
PubMed1980

[Prolactin adenomas in children (author's transl)].

During the last four years 12 Prolactin (PRL) secreting adenomas whose first clinical manifestation appeared before the age of 15 years have been studied. The first signs were a decreased growth rate and arrest of pubertal development in 4 girls and 2 boys in whom the adenoma occurred before or during puberty. In the other six cases (5 girls and 1 boy) the first signs were secondary amenorrhea and galactorrhea in girls and in the boy gynecomastia followed by galactorrhea. Symptoms of the tumour (headaches, and visual disturbances) were almost invariable (11/12) and led to the diagnosis in two cases. Plasma PRL levels were always elevated (80 to more than 5,000 ng/ml) and did not rise in response to TRH. 11 out of 12 were large tumours and pituitary tomography showed that tumour was circumscribed in five cases and invasive in the other seven. The prognosis is related to the short term outcome. The condition may be cured by surgery only (25% cases only) or by surgery and bromocriptine.

Adenoma↗
PubMed1979

[Pituitary microadenoma of Cushing's disease. Course following transsphenoidal excision. Four cases (author's transl)].

Transsphenoidal microsurgery was performed in four patients with a pituitary microadenoma who presented Cushing's disease. Preoperative features were the following: 1) Clinical and laboratory signs of hypercortisolism 2) No radiological evidence of an adrenal tumor 3) Normal or increased ACTH plasma levels 4) Sellar tomograms suggesting the presence of a pituitary microadenoma in only one case. Postoperative outcome after 3 to 30 months follow-up showed persistence or even improved reactivity of the various pituitary functions and especially the early occurence of corticotropin deficiency in all 4 patients. This isolated deficiency regressed spontaneously after 6 and 12 months (2/4 cases). Twenty-four hour studies of ACTH and cortisol profiles and dexamethasone suppression as well as response to metyrapone confirmed the resumption of physiological corticotropin regulation.

Adenoma↗
PubMed1979

The interaction of radioiodinated thyrotropin with human plasma membranes from normal and diseased thyroid glands. Relation of thyrotropin binding to adenylate cyclase activity.

Plasma membranes have been purified from homogenates of normal human thyroid glands and multinodular euthyroid and Graves' goitres by discontinuous sucrose gradient centrifugation. Preparations of reasonable purity were obtained containing specific binding sites for thyrotropin and thyrotropin-sensitive adenylate cyclase. Optimum conditions for 125I-labeled thyrotropin binding were pH 7.8 and 37 degrees C. Sodium ions and concentration of Tris above 20 mM reduced thyrotropin binding. Human plasma membranes showed no species specificity toward thyrotropins from 3 different species (ox, hog and man). Displacement curves of I125-labeled bovine thyrotropin by unlabeled hormones was in the order of increasing concentrations of bovine, porcine and human highly purified thyrotropins and was inversely related to the specific biological activity of these preparations as determined by the bioassay in the mouse. Analysis of the interaction between membranes and 125I-labeled thyrotropin resulted in curvilinear Scatchard plots which can indicate the presence of two types of sites with high affinity -- low capacity (KD = 5 nM) and low affinity -- high capacity (KD = 500 nM) or site -- site interaction of the negative cooperativity type. No significant difference in binding site characteristics was found in normal and diseased glands (multinodular and Graves' goitres). A good correlation was found at equilibrium and in the conditions of adenylate cyclase assay between receptor occupancy and cyclase activation by b-thyrotropin.

Adenylyl Cyclases↗
PubMed1978

[Pubertal prolactin adenoma. Eight cases (author's transl)].

Among 70 operated patients with a histologically verified prolactin secreting adenoma, 8 cases (7 girls, 1 boy) presented the onset of clinical signs before, during or immediately after puberty. Two different clinical syndromes were detected. In the younger patient group (4 cases), the first clinical signs at the onset of puberty were arrest of both growth and pubertal development. In the four remaining causes where in puberty had been achieved, primary-secondary amenorrhea and galactorrhea were observed. Sellar tomograms revealed the presence of invasive adenoma in 3 patients, and circumscribed (enclosed) adenoma in 5 cases. In 7 cases, surgical management was by the transsphénoïdal approach, while one patient underwent subfrontal surgery. Post-operative results were a function of tumour size. In the seven patients having undergone transsphenoïdal surgery, 4 patients displayed a return to normal prolactin function. In the remaining patients, post-operative management was conducted with bromocriptin and without radiotherapy.

Adenoma↗
PubMed1978

Thyrotropin receptor-adenylate cyclase system in plasma membranes from normal and diseased human thyroid glands.

Thyrotropin binding characteristics and adenylate cyclase (AC) activity of thyroid plasma membranes were studied in 52 tissues from normal and diseased human thyroids. Data from normal glands, Graves' goiters, non toxic multinodular goiters and nodular and perinodular tissue of toxic nodular goiters show the same basal, TSH- and NaF- stimulated adenylate cyclase activities (no. = 45; 34.1 +/- 3.2 (m +/- SE), 378 +/- 43, 298 +/- 48 pmol cAMP x min-1 x mg membrane protein-1), the same stimulability of AC by TSH (11.3 +/- 1.4--fold over basal level) and by NaF (8.1 +/- 1.8-fold), the same apparent TSH binding equilibrium constants (5.6 +/- 0.7 and 406 +/- 57 nM) and the same TSH binding site concentrations (2.2 +/- 0.4, 27.8 +/- 5.9 pmol x mg membrane protein-1). Alterations of the TSH receptor and of the AC were detected in membranes from tumoral and metastatic lymph node tissues from thyroid papillary carcinoma and in the thyroid tissue from post-radioiodide therapy thyroiditis. These observations suggest that: (i) hyperthyroidism in Graves' disease or toxic nodular goiter does not result in and is not a consequence of an alteration in the TSH receptor-adenylate cyclase system; (ii) there is no evidence supporting a relationship between the studied membrane properties and clinical or histological status; (iii) membrane abnormalities detected in thyroid carcinoma vary widely; (iv) studies of these membrane alterations might be of interest in the therapeutic management of thyroid carcinoma and may lead to a better understanding of the receptor-adenylate system.

Adenylyl Cyclases↗