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Biomedical subjects

B Vialettes

Publications and source records attributed to B Vialettes.

At least 73 records · Page 4Linked to original sources
PubMed1996

[Corticotropic adenoma in slow adrenal insufficiency].

This case report deals with an insulin-dependent diabetic patient suffering peripheral adrenal insufficiency who, after 12 years of substitutive treatment exhibited resistance to mineralo- and gluco-corticoids with relapse of melanodermia and plasma ACTH levels higher than 1500 pg/ml despite increasing doses. A corticotrop macroadenoma was diagnosed by MR imaging and functional tests and confirmed by surgical excision followed by disappearance of resistance. Pre-operative functional investigation show autonomisation of the adenoma but with some partial persisting regulation. This case report draws attention to this rare either complication or association which can occur in peripheral adrenal insufficiency.

Addison Disease↗
PubMed1995

[Thyrotoxic periodic paralysis. Discussion of the role of Na-K-ATPase, apropos of a case].

We report a case of thyrotoxicosis periodic paralysis (TPP), occurring as a complication of a Grave's disease in a 31 year-old Caucasian male. It has been suggested that the membrane Na-K pump was involved in the pathogenesis of this complication. In our patient, before treatment, the activity of erythrocyte Na-K-ATPase was significantly decreased, as compared with healthy subjects (228nmol Pi/mg prot/h versus 298 + 60 nmol Pi/mg prot/h) and went back to normal levels post treatment. The activity of this enzyme seems to be prone to genetics factors as well as environmental ones. This would explain the higher incidence of TPP in male and in asiatic people. However, other reports emphasize the role of Na-K-pump-independent potassium influx, which would be more specific of TPP.

Adult↗
PubMed1995

Macular pattern dystrophy associated with a mutation of mitochondrial DNA.

PURPOSE/METHODS: To establish association of a macular pattern dystrophy with maternally inherited diabetes and deafness, a new subtype of diabetes mellitus caused by a mutation of mitochondrial DNA (mtDNA). Two probands of two different families with maternally inherited diabetes and deafness were examined. RESULTS/CONCLUSION: Both probands exhibited a macular pattern dystrophy, maternally inherited in one patient. The association of a macular pattern dystrophy with diabetes should lead to screening for a mutation of mtDNA.

Adult↗
PubMed1995

Immunogenicity of long-term intraperitoneal insulin administration with implantable programmable pumps. Metabolic consequences.

OBJECTIVE: To assess immunogenicity of intraperitoneal insulin infusion via implanted pumps by two methods and to evaluate the possible influence of an increased antibody level on metabolic and clinical parameters. RESEARCH DESIGN AND METHODS: We studied insulin antibody levels in 17 type I diabetic patients before and until 24 months after implantation of a programmable pump delivering insulin intraperitoneally. Antibody levels were determined by radioimmunoassay (RIA) and enzyme-linked immunosorbent assay (ELISA). They were correlated with HbA1c, insulin requirements, free insulin, and the incidence of hypoglycemia. RESULTS: Insulin antibodies increased as soon as the 3rd month after implantation. This increase was sustained throughout the study period (month 0, 25.4 +/- 16.2%; month 3, 41.2 +/- 23.5%; month 12, 45.9 +/- 26%; month 24, 48.7 +/- 25%). The data was correlated with the two assay methods (RIA and ELISA). Postimplantation level was correlated with preimplantation level, which could indicate a predictive value of the latter . No correlation was observed with any metabolic parameters, particularly the number of hypoglycemic episodes. CONCLUSIONS: Our results indicate that intraperitoneal insulin administration by implantable programmable pumps leads to an increase of insulin antibodies, which are probably high-affinity antibodies (recognized by both RIA and ELISA). This increase in insulin immunogenicity did not induce significant metabolic consequences, which is reassuring for the future of programmable insulin pumps.

Adult↗
PubMed1995

Extra-pancreatic manifestations in diabetes secondary to mitochondrial DNA point mutation within the tRNALeu(UUR) gene.

OBJECTIVE: A point mutation in the mitochondrial genome has been identified as a cause of diabetes and deafness. We report two pedigrees with and A-to-G transition at nucleotide 3243 of mtDNA within the tRNALeu(UUR) gene and focus our investigations on other localizations of the anomaly, particularly muscle and retina. RESEARCH DESIGN AND METHODS: Muscular localization has been studied in probands by invasive and noninvasive methods, including muscle biopsy (evaluation of the proportion of mutated mtDNA in comparison to blood cells, measurement of respiratory chain complex activities and histological and histochemical aspects) and 31P-nuclear magnetic resonance (NMR) spectroscopy. Ophthalmic and angiographic examination of retina, electroretinography, and visual evoked potentials were performed in five subjects. RESULTS: This mutation, previously described in patients with mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS), was expressed more abundantly in muscle than in nucleated blood cells. This low expression in blood cells could hamper the diagnosis for some patients. In addition, despite poor clinical expression, muscle was found to be highly affected. Ragged red fibers and dystrophic mitochondria were observed in muscle biopsy. Histochemical assays showed decreased activity of respiratory chain complexes, and 31P-NMR in vivo data further confirmed the defect of muscle oxidative processes. Exercise-induced lactate production was increased. Finally, in both families, an atypical "salt and pepper" pigmentary retinopathy was observed without consequences on visual acuity. CONCLUSIONS: In diabetes secondary to 3243 mtDNA mutation, infraclinical muscular and ocular lesions are frequent. These two locations of the disease, which are easily investigated by simple methods, can help in the diagnosis of this new type of diabetes.

Adult↗
PubMed1995

Dietary protection against diabetes in NOD mice: lack of a major change in the immune system.

Pregestimil, a hypoallergenic infant formula in which casein hydrolysate replaces protein, protects NOD mice against diabetes, a T-cell-mediated autoimmune disease. Female and cyclosphosphamide (Cy)-treated male NOD mice were used to assess whether a modification of cellular immune mechanisms occurred when animals were fed Pregestimil from weaning to 110 days of life. Insulitis, sialitis and thyroiditis were observed, and the splenic T-cell proliferative response was measured. The ability of splenic T-cells of NOD mice in the Pregestimil group to transfer diabetes adoptively to young irradiated male NOD mice was also assessed. Pregestimil protected female NOD mice against spontaneous diabetes and male NOD mice against acute Cy-induced diabetes. Addition of bovine serum albumin (10%) to the diet did not alter the preventive effect. The Pregestimil diet also lessened insulitis severity in Cy-treated males, though not in females. Sialitis and thyroiditis, observed mainly in females, were not modified by the diets. The TCR-mediated proliferative response of splenocytes tended to increase specifically in Pregestimil-fed and Cy-treated males. Sensitivity to IL-2 was improved. In females, the TCR-mediated proliferative response and the ability of T cells to transfer diabetes adoptively were unchanged. It is concluded that the protective effect of Pregestimil against diabetes in NOD mice cannot be explained by major changes in peripheral immune response.

Aging↗
PubMed1994

[Outlook for the future in the treatment of diabetic retinopathy].

With regard to diabetic retinopathy, in addition to the demonstration by the DCCT study that prevention is achieved by good metabolic control, our present knowledge on physiopathology leads us to imagine three types of possible therapeutic approach; inhibition of glucotoxicity, improvement of capillary flow, blockade of angiogenesis. 1) Inhibition of glucotoxicity Aldose reductase inhibitors can prevent cataract in diabetic or galactosemic rats. The effect of these drugs on retinopathy, evaluated in some clinical trials, remains controversial, suggesting a minor role. Aminoguanidine is an inhibitor of formation of advanced glycosylation end-products (AGE). This compound has been tested on a model of experimental retinopathy in rats. Parallel to the AGE decrease in retina, formation of microaneurysms and loss of endothelial cells in capillaries were delayed. Clinical tolerance allows human application and randomised trials will give further information on this potentially efficient drug. 2) Improvement of capillary flow This objective can be obtained by drugs inhibiting platelet aggregation or improving erythrocyte or leucocyte deformability. Clinical trials using such compounds were not very conclusive. 3) Blockade of angiogenesis Proliferation of new vessels is a rather severe stage of diabetic retinopathy. Angiogenesis is due to factors locally produced (as FGF, TGF and u-PA produced by anoxic tissues), systemic (IGF-1) or released by inflammatory reaction (IL1, TNF alpha and beta). One imagines usage of drugs which inhibit these factors and prevent angiogenesis. At the present time, two approaches have been used in proliferative retinopathy worsening despite panphotocoagulation; analogues of somatostatin and interferon alpha. The promissing results of these pilot studies have to be confirmed.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

[Adrenal insufficiency and antiphospholipid syndrome].

We report a case of acute adrenal insufficiency secondary to bilateral adrenal hemorrhage, in a 53 year old patient, occurring in the post-operative course of a lower limb ischemia. The patient was found to have a lupus anticoagulant, and it was concluded that the adrenal insufficiency was related to a primary antiphospholipid syndrome (PAPS). The PAPS is a cause of both, acute and chronic adrenal insufficiency. Endocrinologists are relatively little familiar with this etiology. Pathophysiologically, thrombosis and bilateral adrenal hemorrhage can result in progressive bilateral adrenal atrophy, requiring life long substitution. Therefore, the importance to search for antiphospholipid antibodies in the evaluation of acute and chronic adrenal insufficiency has to be emphasized.

Acute Disease↗
PubMed1993

Autoimmune polyendocrine failure--type 1 (insulin-dependent) diabetes mellitus and hypothyroidism--after allogeneic bone marrow transplantation in a patient with lymphoblastic leukaemia.

In this report we describe a patient who, after allogeneic bone marrow transplantation from her HLA-identical sister, developed polyendocrine failure in the form of Type 1 (insulin-dependent) diabetes mellitus and hypothyroidism. This was the result of the transfer of donor lymphoid cells which were activated by allogeneic bone marrow transplantation. The full chimerism of the recipient was demonstrated by restriction fragment length polymorphism analysis from nucleated blood cells and fibroblast DNA. During the 9-year follow-up, the donor developed hypothyroidism and signs of pre-Type 1 diabetes. This clinical observation resembles the adoptive transfer of diabetes observed in non-obese-diabetic mice and BB rats and confirms the role of immune processes in the pathogenesis of this disease.

Adolescent↗
PubMed1993

Incidence rate and risk factors for thyroid dysfunction during recombinant interleukin-2 therapy in advanced malignancies.

Immunotherapy using recombinant interleukin 2 (rIL-2) has been shown to induce thyroid dysfunction in some cancer patients. The purpose of the present study was to evaluate the incidence and risk factors of this adverse autoimmune response. Triiodothyronine, thyroxine and thyrotropin levels were measured serially in 146 consecutive patients treated with rIL-2 for refractory solid tumor (77 patients) or malign hemopathy (69 patients); rIL-2 was administered intravenously in 5-day cycles (18 x 10(6)-24 x 10(6) IU.m-2.day-1) either alone in 79 cases or in combination with autologous bone marrow transplantation in 26 cases, with interferon-gamma in 37 cases, with tumor necrosis factor-alpha in 13 and with cyclophosphamide in five cases. Some patients underwent more than one therapeutic protocol. Peripheral hypothyroidism was present upon entry in nine (6.2%) patients. Thyroid dysfunction appeared or worsened during rIL-2 therapy in 24 (16.4%) patients. Sixteen (10.9%) patients exhibited peripheral hypothyroidism, out of which four exhibited biphasic thyroiditis. Another five (3.4%) patients developed transient hyperthyroidism. Anomaly could not be classified in three patients. Thyroid dysfunction appeared early after one or two cycles. All surviving patients recovered. Only gender and presence of antithyroid antibody were correlated significantly with rIL-2-induced thyroid abnormalities. No correlation was found with any of the other risk factors studied, i.e. type of malignancy, rIL-2 treatment procedure, clinical efficacy, evolution of circulating lymphocyte subsets or other autoimmune antibodies. Antithyroid antibodies were detected in 60.9% of patients with this complication. Thyroid-stimulating antibodies were never detected.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Acute insulin response to glucose and glucagon in subjects at risk of developing type I diabetes.

OBJECTIVE: To determine if knowledge of characteristics of insulin response to various secretagogues during the preclinical phase of type I diabetes may facilitate the diagnosis of subjects at risk. RESEARCH DESIGN AND METHODS: A test consisting of sequential intravenous challenge with glucose (0.3 g/kg) and glucagon (1 mg, 10 min after the end of glucose injection) was performed on 171 ICA- relatives of type I diabetic patients, 18 ICA+ relatives of type I diabetic patients, and 5 transiently hyperglycemic subjects. Acute response to glucose was expressed as the sum of plasma insulin at 2 and 5 min and response to glucagon as the increase in plasma insulin after 10 min. RESULTS: Responses below the lower 95% confidence interval in the ICA- population (40 and 43 microU/ml for glucose and glucagon, respectively) were considered abnormal. The two values were correlated (r = 0.62). Abnormalities coexisted in 2.3% of the ICA- group, 11% of the ICA+ group, and 100% of the transiently hyperglycemic group. All the relatives who subsequently developed diabetes or hyperglycemic subjects who required insulin exhibited combined abnormalities. Some ICA- and ICA+ relatives were tested repeatedly over a follow-up period of 1.5-4 yr. Although the intraindividual coefficient of variation for the two responses was high (28 and 30%), values tended to run parallel in both ICA+ and ICA- relatives. In 2 patients monitored for 2 and 4 yr before diabetes developed, both responses declined at the same rate. In terms of prediction of diabetes, sensitivity of combined abnormalities was high (100%). But compared with the intravenous glucose tolerance test, improvement of specificity by the double challenge was not statistically significant. CONCLUSIONS: Both insulin responses to glucose and glucagon are related. They depend on the secretory capacity of beta-cells and simultaneously become abnormal in the prediabetic phase.

Adolescent↗
PubMed1992

Glutamic acid decarboxylase (GAD) autoantibodies are additional predictive markers of type 1 (insulin-dependent) diabetes mellitus in high risk individuals.

The prevalence of glutamic acid decarboxylase autoantibodies was determined with an immunotrapping enzyme activity assay in newly-diagnosed Type 1 (insulin-dependent) diabetic patients as well as in first-degree relatives using rat brain homogenate as a source of glutamate decarboxylase. Twenty-six out of 86 islet-cell cytoplasmic auto-antibody positive and one out of 24 islet cell autoantibody negative patients of recent onset, had autoantibodies to glutamate decarboxylase above the upper 99% confidence limit obtained from 89 control sera. Among 27 islet cell autoantibody positive relatives including 19 siblings and 8 parents, antibodies to glutamate decarboxylase were found in 8 of 9 (89%) relatives and 7 of 8 (87.5%) siblings with islet cell auto-antibody titres above 20 JDF units, in 1 of 19 (5.2%) relatives with islet cell autoantibody titres between 2 and 5 JDF units, in 2 of 263 (0.7%) siblings and 1 of 139 parents without islet cell autoantibodies. In first-degree relatives, high titre islet cell autoantibodies and autoantibodies to glutamate decarboxylase were tightly associated (X2 = 182, p = 0.0001). None of the relatives with low genetic risk (n = 64), i.e. HLA-different to the diabetic proband, was found to be antibody positive. Antibodies to glutamate decarboxylase were present only in those relatives sharing at least one haplotype with the diabetic proband, including two islet cell autoantibody negative but HLA-identical siblings. Autoantibodies to glutamate decarboxylase were present in 7 of 9 (77%) relatives who developed the disease, including one islet cell autoantibody negative sibling.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗