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V Vlaeminck-Guillem

Publications and source records attributed to V Vlaeminck-Guillem.

14 recordsLinked to original sources
PubMed2005

[Are preoperative examinations useful in the management of patients with renal hyperparathyroidism?].

AIM OF THE STUDY: To evaluate the efficiency of preoperative parathyroid ultrasonography and scintigraphy in the management of renal hyperparathyroidism. PATIENTS AND METHODS: The charts of the last consecutive 200 patients who underwent surgery for renal hyperparathyroidism from 1998 to 2003 were retrospectively reviewed to collect data concerning parathyroid gland function, results of preoperative ultrasonography and scintigraphy, as well as modalities and results of surgical exploration. RESULTS: Ultrasonography and scintigraphy sensibilities were 36.4% and 49.3%, respectively. Efficiency of both examinations was improved when they were combined (sensibility of 64.7%) and in those patients managed for recurrent hyperparathyroidism. Were more often detected by preoperative examinations glands with high weight and/or greatest diameter, orthotopic and inferior glands as well as glands exhibiting nodular hyperplasia content upon pathological examination. CONCLUSION: Parathyroid ultrasonography and scintigraphy are of poor interest in the management of renal hyperparathyroidism. In a preoperative setting, they should be performed only in patients with recurrent disease.

Adult↗
PubMed2001

[Pendred's syndrome. Current features].

Introduction Pendred's syndrome is a recessive autosomal disease, traditionally defined as the association of deaf-mutism, goiter and dysfunctional iodide organization revealed by the perchlorate discharge test. It represents 4 to 10% of the causes of congenital hypoacusis. Although described more than a 100 years ago, the association of thyroid and cochleo-vestibular damage remained unclear for many years. Genetic abnormalities Progress in molecular biology has revealed that the disease is related to alterations in the PDS gene situated on chromosome 7. The PDS gene is responsible for the production of pendrine, protein involved in anion (l-, Cl-) transportation, notably in the apical pole of the thyreocyte and the cochlear duct, where the endolympha is produced. Practical implications The truncation of pendrine related to the genetic alterations be responsible for the morpho-functional alterations in the cochlear apparatus and the thyroid. In this perspective, Pendred's syndrome would appear as a genetic disorder in anion transportation.

Carrier Proteins↗
PubMed2001

[Apoptosis and the thyroid: the Fas pathway].

THE APOPTOTIC FAS/FAS-L PATHWAY: Represents a major apoptotic pathway and involves the specific interaction between a membrane receptor, Fas, harbored by the target cell and a membrane ligand, Fas-L, harbored by the cytotoxic cell. FAS AND NORMAL THYROID GLAND: Normal thyrocytes express Fas receptor but not its ligand. The control of thyroid gland volume results from an equilibrium between the trophic action of TSH and thyrocyte apoptosis, which is limited to some extent by resistance to Fas activation by producing an inhibitor of the apoptotic signal transduction. FAS AND HASHIMOTO'S THYROIDITIS: Aberrant expression of Fas-L by thyrocytes induces their fratricide apoptosis. Thyroid-infiltrating lymphocytes are resistant to apoptosis by overexpressing the antiapoptotic protein Bcl2. FAS AND GRAVES' DISEASE: Autoantibody-dependant stimulation of the thyrotropin receptor favors goiter formation by reducing thyrocyte apoptosis. It induces repression of Fas expression and production of a soluble Fas, whose serum levels are correlated with clinical course. FAS AND THYROID CANCER: Tumoral cells are resistant to apoptosis by inhibiting the apoptotic signal transduction and exert Fas counter-attack by inducing apoptosis of antitumoral lymphocytes.

Apoptosis↗
PubMed2001

Pseudohypoparathyroidism Ia and hypercalcitoninemia.

Pseudohypoparathyroidism Ia (PHP Ia) is characterized by resistance to PTH and many other stimuli because of deficiency of stimulatory G protein alpha-subunit. To determine the incidence, natural history, and mechanism of C cell dysfunction in PHP, calcitonin assays were performed in six patients with PHP Ia and four with pseudopseudohypoparathyroidism from three unrelated families. Controls included healthy subjects and patients with PHP Ib or hypoparathyroidism. The mean basal level of calcitonin was higher in PHP Ia patients than in controls (95.3 +/- 112.7 vs. 3.7 +/- 2.4 pg/mL; P = 0.005; n < 10). In PHP Ia patients, calcitonin levels rose over the normal range (30 pg/mL) after pentagastrin infusion in five patients and remained normal in one. Familial medullary thyroid carcinoma was clinically, biologically, and ultrasonographically ruled out over a mean follow-up exceeding 3 yr. Genomic screening for RET protooncogene mutations failed to reveal any anomaly. The calcitonin infusion test, which induced a significant increase in plasma cAMP in controls 30 and 60 min after infusion, failed to produce this response in PHP Ia patients, suggesting that the action of calcitonin was specifically impaired. PHP Ia may therefore be an independent etiology of hypercalcitoninemia and hyperresponsiveness to pentagastrin infusion.

Adult↗
PubMed2000

The Ets family member Erg gene is expressed in mesodermal tissues and neural crests at fundamental steps during mouse embryogenesis.

The Erg gene belongs to the Ets family encoding a class of transcription factors. To gain new insight on the in vivo functional specificity of the Erg gene within the wide Ets family, we used in situ hybridization to determine its expression pattern during murine embryogenesis. We found that the Erg gene expression predominates in mesodermal tissues, including the endothelial, precartilaginous and urogenital areas. A specific Erg gene expression was also identified in migrating neural crest cells. A comparison with Fli-1, the most closely Erg-related gene, revealed that both gene expressions partially overlap, suggesting that they may contribute to related functions in these tissues. Like other Ets family genes, Erg seems involved in several fundamental developmental steps in murine embryogenesis, including epithelio-mesenchymal transition, cell migration, settlement and differentiation.

Animals↗
PubMed2000

Resistance to thyroid hormone in a family with no TRbeta gene anomaly: pathogenic hypotheses.

UNLABELLED: Syndromes of resistance to thyroid hormone (RTH) are almost always linked to a defective triiodothyronine-receptor B gene (TRB). Only six families with RTH exhibiting a normal TRB gene have been reported so far. We report another and discuss possible mechanisms. PATIENTS AND METHODS: We studied a kindred expressing a typical RTH phenotype. DNA was amplified and the TRB gene was sequenced. Linkage analysis assessed linkage between the TRB gene and RTH phenotype. RESULTS: Direct sequencing of the TRB gene failed to identify any anomaly in the coding exons. Linkage analysis demonstrated that the RTH phenotype was not linked to the TRB gene in this family. CONCLUSION: TRB1 and TRB2 genes were not defective in this family. Multiple mechanisms might account for this situation at the pre-receptor, receptor and post-receptor levels. The most likely hypothesis is the involvement of an abnormal nuclear cofactor serving a specific function in the regulation of thyroid hormone action.

Adult↗
PubMed2000

[Physiology and pathophysiology of thyroid hormone receptors: the contributions of murine models].

Thyroid hormones are involved in vertebrate development and metabolic homeostasis. Their actions are mediated through several nuclear receptors encoded by TRalpha and TRB genes. The interspecies conservation of 3 functional receptors (TRalpha1, TRB1 and TRB2) and their partially distinct tissue distribution suggest that they serve non-redundant physiological functions. The exclusive TRB gene involvement in the resistance to thyroid hormone (RTH) reinforces the hypothesis of a functional specificity. Recent mouse knock-out and transgenesis methods allow invalidation or overexpression of a gene of interest, respectively. They therefore provide powerful means to determine the specific function of a gene and have been applied to the thyroid hormone receptor genes. Mice TRB(-/-) represent a model of the recessive form of RTH. They have been shown to develop goiter and high thyroid hormone and TSH (Thyroid Stimulating Hormone) levels, suggesting an unique role for TRB in the negative regulation of TSH pituitary secretion. The associated disorder in audition maturation also showed that TRB plays an essential role in the development of audition. By contrast, mice TRalpha(-/-) exhibited thyroid gland atrophy along with decreased thyroid hormones and TSH levels. Clinical phenotype included growth interruption and retardation of both intestine and bone maturation, but no hearing loss. Mice TRalphaB(-/-) combined the disorders, including delayed neonatal development despite hyperactive hypothalamus-pituitary axis. Finally, transgenic overexpression of a mutant TRB gene reproduced the dominant form of RTH and confirmed the major role of dominant negative activity in the occurrence of some phenotypic key-features such as high circulating hormone levels despite high TSH levels, hyperactivity and lack of severe hearing loss. From these studies, it is suggested that TRalpha and TRB receptors are to some extent able to cooperate or substitute for each other. However some organs constitute TR-specific T3 target-tissues such as inner ear, pituitary, heart, liver, bone and small intestine.

Animals↗
PubMed2000

Liver transplantation eliminates insulin needs of a diabetic patient.

Organ transplantation and subsequent therapeutic agents may induce or worsen preexisting diabetes mellitus. We report the case of a diabetic patient whose insulin needs disappeared after liver transplantation. Non insulin-dependent diabetes mellitus was diagnosed when she was 47, and was treated by hypoglycemic drugs and then insulin. Chronic post-hepatitis C cirrhosis was diagnosed at the age of 55 and required liver transplantation 2 years later. During the postoperative course, the insulin doses required to maintain normal glucose levels progressively decreased, and insulin became completely unnecessary by the 29(th) postoperative day. After insulin was stopped, glucose levels remained within normal ranges for the 5-year-long follow-up, despite the worsening of a preexisting diabetic nephropathy and the occurrence of a diabetic retinopathy. This case highlights the fact that liver transplantation may eliminate insulin needs in a diabetic patient but also shows that degenerative complications may occur despite apparent remission of diabetes.

Aged↗
PubMed1999

[Pseudohypoparathyroidism and the concept of hormonal resistance. Diagnosis, classification and therapy].

CLINICAL AND BIOLOGICAL FEATURES: Pseudohypoparathyroidism is a heterogenous group of conditions with variable clinical and biological features and a common resistance to parathormone (PTH) leading to hypocalcemia associated with high levels of PTH. The classification of these conditions depends on the expression of Albright's osteodystrophy and response to exogenous parathormone: urine phosphorus and cyclic AMP excretion. TYPE IA: The characteristic feature is Albright's osteodystrophy associated with a totally negative response to exogenous PTH. Defective protein G is the cause. Pseudopseudohypoparathyroidism is defined by Albright's osteodystrophy without resistance to PTH. This condition occurs in families with type Ia pseudohypoparathyroidism. It is also related to a defect in protein G. TYPE IB: Type Ib corresponds to PTH resistance alone, without Albright's osteodystrophy. This condition is apparently secondary to anomalous regulation of the gene coding the PTH receptor. TYPE II: Type II is defined by the inconstant presence of Albright's osteodystrophy and a dissociated response to PTH: urinary phosphorus does not respond to PTH (hormone resistance) but urine cyclic AMP increases in response to PTH suggesting anomalous signal transduction downstream from adenyl cyclase. TREATMENT: In all types, treatment is based on combining calcium therapy and vitamin D supplementation under rigorously controlled conditions.

Calcium↗
PubMed1999

[Pseudohypoparathyroidism and the concept of hormonal resistance. Types Ia and Ic and pseudohypoparathyroidism].

TYPE IA: This familial hereditary condition is characterized by the association of Albright's osteodystrophy, resistance to parathormone (PTH) and a negative PTH test both for urinary phosphorus and cyclic AMP. The condition is caused by an anomalous alpha sub-unit of protein G, impairing its function. The result is defective transmembrane transduction of the PTH mediated signal. Protein G, coupled with all heptahelical membrane-spanning receptors, is ubiquitous, explaining the association of multiple hormone and neurosensory resistances. Resistance of the thyrotrope and gonadotrope axes should be explored to institute appropriate replacement therapy. TYPE IC: This type associates all the clinical and biological features of type Ia pseudohypoparathyroidism but without any protein G defect, suggesting another effector of signal transduction, perhaps adenylate cyclase, is involved. PSEUDOPSEUDOHYPOPARATHYROIDISM: Often in families with type Ia pseudohypoparathyroidism, subjects with Albright's osteodystrophy alone, with no features of PTH resistance, are said to have pseudopseudohypoparathyroidism. Protein G defects are also demonstrated in these subjects, confirming the relationship with type la pseudohypoparathyroidism and explaining the possible multiple hormone resistances observed. The phenotypic variability between type Ia pseudohypoparathyroidism and pseudopseudohypoparathyroidism would be related to genomic imprinting mechanism.

Genotype↗
PubMed1999

[Pseudohypoparathyroidism and the concept of hormonal resistance. Types Ib and II].

TYPE IB PSEUDOHYPOPARATHYROIDISM: Parathormone resistance is the only manifestation of type Ib pseudohyoparathyroidism, the Albright osteodystrophy and multiple hormone resistance described in type Ia are not observed. In type Ib there is a certain preservation of bone sensitivity to parathormone although the main target organ, the kidney, is resistant. Consequently, excessive bone remodeling can be evidenced by X-ray (subperiosteal resorption, fibrocystic osteitis), chemistry (high serum alkaline phosphatase and osteocalcin, and increased urine hydroxyproline), densitometry (lower bone density), and pathology (reduction in trabecular bone volume). The dissociation of the bone and kidney response corresponds to the pseudohypohyperthyroidism described by certain authors. The genetic substratum leading to type Ib pseudohypoparathyroidism remains to be identified. The pathogenic mechanism generally hypothesized concerns a qualitative or quantitative anomaly of the parathormone receptor but seems to be disproved by recent studies. TYPE II PSEUDOHYPOPARATHYROIDISM: Here there is a characteristic lack of a rise in urine phosphorus, signaling parathormone resistance, and stimulated urinary excretion of cyclic AMP, an expression of the integrity of the transmembrane transduction of the parathormone mediated signal and thus protein G and adenylate cyclase. The anomaly could thus involve a transductional effector situated downstream from adenylate cyclase which would explain the symptoms of type II pseudo-hypoparathyroidsm, with both parathormone resistance and Albright osteodystrophy.

Genotype↗
PubMed1999

[Thyroid hormone resistance syndromes: clinical aspects].

INTRODUCTION: Syndromes of resistance to thyroid hormone correspond to variable clinical states which are usually transmitted as autosomal dominant traits and characterized by the lack of sensitivity of target tissues to triiodothyronine (T3). The diagnosis has to be performed in order to offer an appropriate therapy. CURRENT KNOWLEDGE AND KEY POINTS: Clinical states range between two extremes: the generalized form, with global euthyroidism, and the predominantly pituitary form, with thyrotoxicosis. Surprisingly, these various clinical situations are usually determined by the same genetic defect, i.e., an anomaly of one of the two alleles of the gene encoding the thyroid hormone receptor TR beta. High levels of circulating thyroid hormones in the presence of detectable thyroid stimulating hormone (TSH) levels is the characteristic biological feature. Pituitary thyreotropic adenoma, another etiology of inappropriate secretion of TSH, needs thus to be ruled out. No treatment is required in case of generalized resistance to thyroid hormone, whereas two specific drugs (TRIAC and D-T4) appear to be useful in the predominantly pituitary form. FUTURE PROSPECTS AND PROJECTS: Mechanisms of resistance have been well documented, therefore allowing better understanding of T3 action on its nuclear receptor. Several transcriptional cofactors or corepressors have been identified and have to be investigated to explain the intriguing inter- and intra-familial, and even intra-individual, phenotypic variability. New insights should, furthermore, be gained from these studies to precisely determine how therapeutic agents work in resistance to thyroid hormone.

Humans↗