Diagnostic procedure in suspected Graves' disease

Diagnostic procedure in suspected Graves' disease has never been studied scientifically and actual practice seems quite variable, notably between countries. Recommendations are few and weak (expert opinion). This article presents the recommendations of an expert consensus meeting organized by the French Society of Endocrinology in 2016. In case of clinically suspected thyrotoxicosis, the first-line biological assessment is of thyroid-stimulating hormone (TSH). Free T4 and possibly free T3 assays assess biological severity and are necessary for treatment efficacy monitoring. Positive diagnosis of Graves' disease after biological confirmation of thyrotoxicosis does not always require complementary etiological examinations if clinical presentation is unambiguous, notably including extra-thyroid signs. Otherwise, first-line anti-TSH-receptor (TSH-R) antibody screening is recommended for its good intrinsic performance (sensitivity and specificity) and ease of access in France. Scintigraphy is reserved to rare cases of Graves' disease with negative antibody findings or when another etiology is suspected. Thyroid ultrasound scan may be contributive, but is not recommended in first line.

Classification of Patients With GH Disorders May Vary According to the IGF-I Assay

CONTEXT

Insulinlike growth factor I (IGF-I) measurement is essential for the diagnosis and management of growth hormone (GH) disorders. However, patient classification may vary substantially according to the assay technique.

OBJECTIVE

We compared individual patient data and classifications obtained with six different IGF-I assay kits in a group of patients with various GH disorders.

DESIGN

In this cross-sectional study, we measured IGF-I with six immunoassays in 102 patients with active or treated acromegaly or GH deficiency. IGF-I normative data previously established for the same six assay kits were used to classify the patients (high, low, or normal IGF-I levels), using both raw data and standard deviation scores (SDSs). Pairwise concordance between assays was assessed with Bland-Altman plots and with the percentage of observed agreement and the weighted κ coefficient for categorized IGF-I SDS.

RESULTS

We observed marked variability both across each individual's IGF-I raw data and across IGF-I SDS values obtained with each of the six immunoassays. Pairwise concordance between assay values, as assessed with the weighted κ coefficient, ranged from 0.50 (moderate) to 0.81 (excellent).

CONCLUSION

Even when using normative data obtained in the same large population of healthy subjects and when using calculated IGF-I SDSs, agreement among IGF-I assay methods is only moderate to good. Differences in assay performance must be taken into account when evaluating and monitoring patients with GH disorders. This argues for the use of the same IGF-I assay for a given patient throughout follow-up.

Reference Values for IGF-I Serum Concentrations: Comparison of Six Immunoassays

CONTEXT

Measurement of IGF-I is essential for diagnosis and management of patients with disorders affecting the somatotropic axis. However, even when IGF-I kit manufacturers follow recent consensus guidelines, different kits can give very different results for a given sample.

OBJECTIVES

We sought to establish normative data for six IGF-I assay kits based on a large random sample of the French general adult population.

SUBJECTS AND METHODS

In a cross-sectional multicenter cohort study, we measured IGF-I in 911 healthy adults (18-90 years) with six immunoassays (iSYS, LIAISON XL, IMMULITE, IGFI RIACT, Mediagnost ELISA, and Mediagnost RIA). Pairwise concordance between assays was assessed with Bland-Altman plots for both IGF-1 raw data and standard deviation scores (SDS), as well as with the percentage of observed agreement and the weighted Kappa coefficient for categorized IGF-I SDS.

RESULTS

Normative data included the range of values (2.5-97.5 percentiles) given by the six IGF-I assays according to age group and sex. A formula for SDS calculation is provided. Although the lower limits of the reference intervals of the six assays were similar, the upper limits varied markedly. Pairwise concordances were moderate to good (0.38-0.70).

CONCLUSION

Despite being obtained in the same healthy population, the reference intervals of the six commercial IGF-1 assay kits showed noteworthy differences. Agreement between methods was moderate to good.

Prevalence and determinants of vitamin D deficiency in healthy French adults: the VARIETE study

The U.S. Institute of Medicine considers that a serum 25-hydroxyvitamin D (25OHD) concentration >20 ng/mL corresponds to optimal vitamin D status in the general population. Old studies of vitamin D status in the French general population have demonstrated high prevalence of insufficiency. We measured serum 25OHD, 1,25(OH)2D, PTH, calcium, phosphorus, and creatinine levels in 892 French Caucasian healthy subjects (463 men, 429 women) aged from 18 to 89 years. The 25OHD concentration was similar in men (24.1 ± 8.2 ng/mL) and women (23.4 ± 8.0 ng/mL). 25OHD concentrations of <10, <12, <20, and <30 ng/mL were found in respectively 6.3, 9.9, 34.6, and 80.3 % of subjects. Residence in northern France (odds ratio [OR] 1.91), blood sampling between January and March (OR 7.74), BMI ≥24 kg/m(2) (OR 1.81), and age 60 years or more (OR 1.99) were significant determinants of hypovitaminosis D (25OHD <20 ng/mL). The serum 25OHD level correlated positively with 1,25(OH)2D and negatively with PTH. 25OHD values below 20 ng/mL were associated with lower 1,25(OH)2D levels, and 25OHD values below 27 ng/mL were associated with higher PTH levels. Many French healthy adults have a 25OHD concentration <20 ng/mL, especially during winter months. Actions to improve the vitamin D status of the French general population are urgently needed.

Prenatal exposure to persistent organic pollutants and organophosphate pesticides, and markers of glucose metabolism at birth

BACKGROUND

Experimental evidence suggests that developmental exposure to persistent organic pollutants (POP) and to some non persistent pesticides may disrupt metabolic regulation of glucose metabolism and insulin secretion, and thereby contribute to the current epidemic of obesity and metabolic disorders. Quasi-experimental situations of undernutrition in utero have provided some information. However, the evidence in humans concerning the role of the prenatal environment in these disorders is contradictory, and little is known about long-term outcomes, such as type 2 diabetes, of prenatal exposure.

OBJECTIVES

Our aim was to evaluate the effects of prenatal exposure to POP and organophosphate pesticides on fetal markers of glucose metabolism in a sample of newborns from the Pelagie mother-child cohort in Brittany (France).

METHODS

Dialkylphosphate (DAP) metabolites of organophosphate pesticides were measured in maternal urine collected at the beginning of pregnancy. Cord blood was assayed for polychlorinated biphenyl congener 153 (PCB153), p,p'-dichlorodiphenyl dichloroethene (DDE) and other POP. Insulin and adiponectin were determined in cord blood serum (n=268).

RESULTS

A decrease in adiponectin and insulin levels was observed with increasing levels of DDE, but only in girls and not boys. Adiponectin levels were not related to the concentrations of other POP or DAP metabolites. Decreasing insulin levels were observed with increasing PCB153 concentrations. Insulin levels increased with DAP urinary levels. Additional adjustment for BMI z-score at birth modified some of these relations.

CONCLUSIONS

Our observations bring support for a potential role of organophosphate pesticides and POP in alterations to glucose metabolism observable at birth.

Serum PTH reference values established by an automated third-generation assay in vitamin D-replete subjects with normal renal function: consequences of diagnosing primary hyperparathyroidism and the classification of dialysis patients

OBJECTIVE

To determine parathyroid hormone (PTH) reference values in French healthy adults, taking into account serum 25-hydroxyvitamin D (25OHD), renal function, age, gender, and BMI.

PARTICIPANTS AND MAIN BIOLOGICAL MEASUREMENTS

We studied 898 healthy subjects (432 women) aged 18-89 years with a normal BMI and estimated glomerular filtration rate (eGFR), 81 patients with surgically proven primary hyperparathyroidism (PHPT), and 264 dialysis patients. 25OHD and third-generation PTH assays were implemented on the LIAISON XL platform.

RESULTS

Median PTH and 25OHD values in the 898 healthy subjects were 18.8  ng/l and 23.6  ng/ml respectively. PTH was lower in subjects with 25OHD ≥30  ng/ml than in those with lower values. Among the 183 subjects with 25OHD ≥30  ng/ml, those aged ≥60 years (n=31) had higher PTH values than younger subjects, independent of 25OHD, BMI, and eGFR (P<0.001). Given the small number of subjects aged ≥60 years, we adopted the 95% CI of PTH values for the entire group of 183 vitamin D-replete subjects (9.4-28.9  ng/l) as our reference values. With 28.9  ng/l as the upper limit of normal (ULN) rather than the manufacturer's ULN of 38.4  ng/l, the percentage of PHPT patients with 'high' PTH values rose to 90.1% from 66.6% (P<0.001), and 18.6% of the dialysis patients were classified differently in view of the KDIGO target range (two to nine times the ULN).

CONCLUSION

When only subjects with 25OHD ≥30  ng/ml were included in the reference population, the PTH ULN fell by 22.4%, diagnostic sensitivity for PHPT improved, and the classification of dialysis patients was modified.

Serum calcitriol concentrations measured with a new direct automated assay in a large population of adult healthy subjects and in various clinical situations

The measurement of calcitriol [1,25(OH2)D], is important for the differential diagnosis of several disorders of calcium/phosphorus metabolism but is time-consuming and tricky. We measured serum calcitriol with a new automated direct assay on the Liaison XL platform in 888 healthy French Caucasian subjects aged 18-89 years, 32 patients with a surgically-proven PHPT, 32 pregnant women at the end of the first and at the end of the third trimester, and 24 dialysis patients before and after one year of supplementation with vitamin D3 or placebo. The mean calcitriol concentration (±SD) in the healthy population was 52.9±14.5 ng/L with a 95% CI interval of 29-83.6 ng/L. In PHPT patients, calcitriol concentration was 81.6±29.0 ng/L, 15 of them (46.9%) having a concentration >83.6 ng/L. In pregnant women, calcitriol was 80.4±26.4 ng/L at the end of the first trimester, and 113.1±33.0 ng/L at the end of the third trimester, 12 (37.5%) and 26 (81.3%) of them having a calcitriol concentration >83.6 ng/L at the first and third trimesters respectively. In 14 dialysis patients, calcitriol was 9.5±7.7 ng/L and rose to 19.3 ng/L after one year of supplementation with 50,000 IU vitamin D3/month. In 10 other dialysis patients, calcitriol was 9.9±2.9 ng/L and remained stable (12.4±3.7 ng/L) after one year of placebo. In conclusion, this new automated calcitriol assay, in addition to presenting excellent analytical performances, gives the expected variations in patients compared to "normal" values obtained in an extensive reference population.

Perinatal exposure to chlordecone, thyroid hormone status and neurodevelopment in infants: the Timoun cohort study in Guadeloupe (French West Indies)

BACKGROUND

Perinatal exposure to endocrine-disrupting chemicals may affect thyroid hormones homeostasis and impair brain development. Chlordecone, an organochlorine insecticide widely used in the French West Indies has known estrogenic and progestin properties, but no data is available, human or animal, on its action on thyroid hormone system.

OBJECTIVES

Our aim was to evaluate the impact of perinatal exposure to chlordecone on the thyroid hormone system of a sample of infants from the Timoun mother-child cohort in Guadeloupe and their further neurodevelopment.

METHODS

Chlordecone was measured in cord blood and breast milk samples. Thyroid stimulating hormone (TSH), free tri-iodothyronine (FT3), free thyroxine (FT4) were determined in child blood at 3 months (n=111). Toddlers were further assessed at 18 months using an adapted version of the Ages and Stages Questionnaire (ASQ).

RESULTS

Cord chlordecone was associated with an increase in TSH in boys, whereas postnatal exposure was associated with a decrease in FT3 overall, and in FT4 among girls. Higher TSH level at 3 months was positively associated with the ASQ score of fine motor development at 18 months among boys, but TSH did not modify the association between prenatal chlordecone exposure and poorer ASQ fine motor score.

CONCLUSIONS

Perinatal exposure to chlordecone may affect TSH and thyroid hormone levels at 3 months, differently according to the sex of the infant. This disruption however did not appear to intervene in the pathway between prenatal chlordecone exposure and fine motor child development.

Neutralizing antibodies and fatigue as predictors of low response to interferon-beta treatment in patients with multiple sclerosis

Background

The clinical impact of neutralizing antibodies against interferon-beta (NAb) is controversial. Their presence can lead to a decrease in interferon-beta (IFNβ) efficacy. Fatigue reported in patients with multiple sclerosis (MS) may be associated with an unfavorable clinical course. We conducted a prospective multicentre study to assess the association between response to IFNβ, NAb and fatigue.

Methods

Patients with relapsing-remitting MS on IFNβ treatment were included. During the second year of treatment, the patients were analyzed for NAb status and non-response criteria to IFNβ (number of relapses ≥1 during the follow-up period, increase in the Expanded Disability Status Scale ≥0.5). The score on the Modified Fatigue Impact Scale (MFIS pathological if score ≥35) was noted for each patient.

Results

Of the 176 patients included: 22.3% were NAb positive, 54.5% presented non-response criteria to IFNβ, and 57.4% had a pathological MFIS score. Fatigue was increased in NAb + patients (p = 0.0014) and they were more likely to present non-response criteria to IFNβ (p = 0.041) than NAb- patients. Multivariate logistic regression analysis showed that the presence of NAb was related to fatigue (p = 0.0032) and denoted disease activity in these patients (p = 0.026).

Conclusions

This study demonstrates the impact of NAb on the non-clinical response to IFNβ. Fatigue assessment is an indicator of IFNβ responsiveness and a predictive biomarker of deterioration on patient’s neurological status.

Ten-year improvement of insulin resistance and growth with recombinant human insulin-like growth factor 1 in a patient with insulin receptor mutations resulting in leprechaunism

AIM

Leprechaunism, a rare genetic disease resulting from mutations in two alleles of the insulin receptor gene, is characterized by severe insulin resistance, retarded growth and, usually, premature death. The ability of treatment with recombinant human insulin-like growth factor 1 (rhIGF1) to improve metabolic and clinical parameters in the long-term is still controversial.

METHODS

Mutations were looked for in the insulin receptor gene of a four-month-old female baby with leprechaunism. The patient's skin fibroblasts were analyzed for response to insulin and IGF1. At the clinical level, the very long-term effects of treatment with rhIGF1/rhIGFBP3 were evaluated by clinical and metabolic parameters.

RESULTS

The patient's diagnosis was based on compound heterozygous mutations in two alleles of the insulin receptor gene, thus confirming leprechaunism. Cultured fibroblasts showed a decreased number of insulin receptors and were insulin-resistant. However, IGF1 was able to stimulate IGF1 receptor signalling, suggesting possible activation of a salvage pathway. Treatment with IGF1/IGFBP3 for 8.7 years, then IGF1 for 2 years, resulted in normalization of circulating levels of IGF1 and IGFBP3. Large daily variations in glycaemia and insulinaemia persisted, but mean glycaemia decreased. Regarding growth, the patient's BMI Z score normalized and length/height score improved. Our patient presented normal neurological development and academic achievement. The treatment was free of adverse effects.

CONCLUSION

Our results provide evidence that rhIGF1 with and without rhIGFBP3 can prevent fatal outcomes, and improve growth and metabolic parameters, for more than 10 years in a patient with leprechaunism. Long-term rhIGF1 for severe insulin resistance syndrome should be considered.

Anoctamin-1/TMEM16A is the major apical iodide channel of the thyrocyte

Iodide is captured by thyrocytes through the Na(+)/I(-) symporter (NIS) before being released into the follicular lumen, where it is oxidized and incorporated into thyroglobulin for the production of thyroid hormones. Several reports point to pendrin as a candidate protein for iodide export from thyroid cells into the follicular lumen. Here, we show that a recently discovered Ca(2+)-activated anion channel, TMEM16A or anoctamin-1 (ANO1), also exports iodide from rat thyroid cell lines and from HEK 293T cells expressing human NIS and ANO1. The Ano1 mRNA is expressed in PCCl3 and FRTL-5 rat thyroid cell lines, and this expression is stimulated by thyrotropin (TSH) in rat in vivo, leading to the accumulation of the ANO1 protein at the apical membrane of thyroid follicles. Moreover, ANO1 properties, i.e., activation by intracellular calcium (i.e., by ionomycin or by ATP), low but positive affinity for pertechnetate, and nonrequirement for chloride, better fit with the iodide release characteristics of PCCl3 and FRTL-5 rat thyroid cell lines than the dissimilar properties of pendrin. Most importantly, iodide release by PCCl3 and FRTL-5 cells is efficiently blocked by T16Ainh-A01, an ANO1-specific inhibitor, and upon ANO1 knockdown by RNA interference. Finally, we show that the T16Ainh-A01 inhibitor efficiently blocks ATP-induced iodide efflux from in vitro-cultured human thyrocytes. In conclusion, our data strongly suggest that ANO1 is responsible for most of the iodide efflux across the apical membrane of thyroid cells.

[Itraconazole: a new drug-related cause of hypertension]

Itraconazole is a triazole agent used in the treatment of fungal infections and in some metastatic cancers. Its use has been associated with cardiovascular adverse events and particularly heart failure with preserved ejection fraction. We report the case of a 68-year-old male patient with a well-controlled hypertension treated with irbesartan 150mg/day since 2007. He developed a pulmonary aspergillosis on post-tuberculosis cavitary lesions treated in July 2011 with itraconazole 200mg/day. Early 2012, his antihypertensive treatment had to be gradually increased to a quadritherapy and his blood pressure was at 157/78mmHg at home. Hypokalemia was observed on several occasions as well as edema of the lower limbs. Plasma renin and plasma and urine aldosterone concentrations on treatment not interfering with the renin angiotensin system were low, associated with normal serum and urine cortisol, ACTH, SDHA and DOC, BNP and creatinine concentrations. Plasma itraconazole values were much above the therapeutic range. Left ventricular ejection fraction was preserved. There were no adrenal or renal artery abnormalities at the CT scan. Three months after stopping itraconazole, hypokalemia and edema disappeared and blood pressure was normalized with less treatment. Plasma renin and aldosterone concentrations were normalized. He had a pulmonary lobectomy for his pulmonary aspergillosis. Itraconazole may induce a resistant hypertension with low renin. The mechanisms of this adverse effect of itraconazole remain unknown.

Diphenyleneiodonium, an inhibitor of NOXes and DUOXes, is also an iodide-specific transporter

NADPH oxidases (NOXes) and dual oxidases (DUOXes) generate O2 (.-) and H2O2. Diphenyleneiodonium (DPI) inhibits the activity of these enzymes and is often used as a specific inhibitor. It is shown here that DPI, at concentrations similar to those which inhibit the generation of O2 derivatives, activated the efflux of radioiodide but not of its analog (99m)TcO4 (-) nor of the K(+) cation mimic (86)Rb(+) in thyroid cells, in the PCCl3 rat thyroid cell line and in COS cell lines expressing the iodide transporter NIS. Effects obtained with DPI, especially in thyroid cells, should therefore be interpreted with caution.

Role of sex steroids, intrahepatic fat and liver enzymes in the association between SHBG and metabolic features

BACKGROUND

SHBG and liver enzymes levels are both associated with the risk of type 2 diabetes. However, the relationship between SHBG with liver enzymes and intrahepatic fat content remain poorly understood.

OBJECTIVE

To investigate whether SHBG is correlated with glucose and lipids levels and whether this association depends on fatty liver content, liver enzymes or sex hormone concentrations.

DESIGN AND PATIENTS

We studied 233 dysmetabolic men with measures of plasma SHBG, total testosterone, 17β-oestradiol, glucose, adiponectin, liver enzymes and hepatokines. Intrahepatic liver fat and visceral fat contents were measured by magnetic resonance imaging in 108 of these individuals.

RESULTS

After adjustment for age, SHBG concentration was inversely correlated with fasting glucose (βstandardized  = -0·21, P = 0·0007), HbA1c (βstandardized  = -0·27, P < 0·0001), triglycerides (βstandardized  = -0·19, P = 0·003) and positively correlated with HDL-Cholesterol (βstandardized  = 0·14, P = 0·03). These correlations persisted after adjustment for either total testosterone or 17β-oestradiol levels. SHBG was not related to either fetuin A or FGF 21 concentrations. The inverse association of SHBG with HbA1c and glycaemia was not altered after adjusting for liver markers but was no longer significant after adjustment for hepatic fat content.

CONCLUSION

The significant association between SHBG and fasting glycaemia, HbA1c and lipid levels in dysmetabolic men was not related to either sex hormones or markers of liver function, but was dependent on intrahepatic fat. This suggests that intrahepatic fat, but not alterations in liver function markers, may be involved in the association between SHBG and glucose and lipid metabolism.

Associations between visceral adipose tissue, inflammation and sex steroid concentrations in men

CONTEXT

In men, obesity and the metabolic syndrome are accompanied by decreased testosterone levels, but little is known about the associations between visceral adipose tissue (VAT), VAT-related inflammation and sex steroids.

OBJECTIVE

To examine the relative impact of VAT, abdominal subcutaneous adipose tissue (SAT) and interleukin 6 (IL-6), a marker of VAT-induced inflammation, on testosterone (T) and 17β-oestradiol (E2) levels in dysmetabolic men.

METHODS

We study the NUMEVOX cohort of 229 men, aged 27-77 years, who all had at least one metabolic syndrome criterion (on average three). IL-6, C-reactive protein, Homeostasis Model Assessment of (HOMA) insulin resistance index (HOMA-IR), liver enzymes, E2, LH, sex hormone-binding globulin (SHBG), T, waist circumference and body mass index (BMI) were measured; bioavailable testosterone (BT) was calculated from T and SHBG; MRI-assessed VAT and SAT were analysed in 109 of these men.

RESULTS

Visceral adipose tissue was strongly correlated with E2 (Spearman r = 0.38, P < 0.001) and with BT/E2 ratio (r = -0.42, P < 0.001), while SAT was not correlated with either. IL-6 was correlated with E2 (r = 0.19, P = 0.007), BT (r = -0.19, P = 0.006) and BT/E2 ratio (r = -0.30 P < 0.001). In multivariate linear analysis, the relation between VAT and E2 was independent of age, BMI (P = 0.008), leptin (P < 0.001), T and SHBG. Log(IL-6) was significantly inversely related with log(BT) (P = 0.032) independently of age, VAT, leptin and HOMA-IR.

CONCLUSIONS

17β-oestradiol levels were positively associated with VAT, but not with SAT, while T and BT were negatively and independently associated with IL-6. The significant inverse association between IL-6 and T suggests an important role of low-grade visceral fat inflammation in the central hypogonadism associated with the metabolic syndrome.

DelK32-lamin A/C has abnormal location and induces incomplete tissue maturation and severe metabolic defects leading to premature death

The LMNA gene encodes lamin A/C intermediate filaments that polymerize beneath the nuclear membrane, and are also found in the nucleoplasm in an uncharacterized assembly state. They are thought to have structural functions and regulatory roles in signaling pathways via interaction with transcription factors. Mutations in LMNA have been involved in numerous inherited human diseases, including severe congenital muscular dystrophy (L-CMD). We created the Lmna(ΔK32) knock-in mouse harboring a L-CMD mutation. Lmna(ΔK32/ΔK32) mice exhibited striated muscle maturation delay and metabolic defects, including reduced adipose tissue and hypoglycemia leading to premature death. The level of mutant proteins was markedly lower in Lmna(ΔK32/ΔK32), and while wild-type lamin A/C proteins were progressively relocated from nucleoplasmic foci to the nuclear rim during embryonic development, mutant proteins were maintained in nucleoplasmic foci. In the liver and during adipocyte differentiation, expression of ΔK32-lamin A/C altered sterol regulatory element binding protein 1 (SREBP-1) transcriptional activities. Taken together, our results suggest that lamin A/C relocation at the nuclear lamina seems important for tissue maturation potentially by releasing its inhibitory function on transcriptional factors, including but not restricted to SREBP-1. And importantly, L-CMD patients should be investigated for putative metabolic disorders.

Cell biology of H2O2 generation in the thyroid: investigation of the control of dual oxidases (DUOX) activity in intact ex vivo thyroid tissue and cell lines

H2O2 generation by dual oxidase (DUOX) at the apex of thyroid cells is the limiting factor in the oxidation of iodide and the synthesis of thyroid hormones. Its characteristics have been investigated using different in vitro models, from the most physiological thyroid slices to the particulate fraction isolated from transfected DUOX expressing CHO cells. Comparison of the models shows that some positive controls are thyroid specific (TSH) or require the substructure of the in vivo cells (MβCD). Other controls apply to all intact cell models such as the stimulation of the PIP(2) phospholipase C pathway by ATP acting on purinergic receptors, the activation of the Gq protein downstream (NaF), or surrogates of the intracellular signals generated by this cascade (phorbol esters for protein kinase C, Ca(++) ionophore for Ca(++)). Still, other controls, exerted by intracellular Ca(++) or its substitute Mn(++), the intracellular pH, or arachidonate bear directly on the enzyme. Iodide acts at the apical membrane of the cell through an oxidized form, presumably iodohexadecanal. Cooling of the cells to 22°C blocks the activation of the PIP(2) phospholipase C cascade. All these effects are reversible. Their kinetics and concentration-effect characteristics have been defined in the four models. A general scheme of the thyroid signaling pathways regulating this metabolism is proposed. The probes characterized could be applied to other H2O2 producing cells and to pathological material.

Early effects of erythropoietin on serum hepcidin and serum iron bioavailability in healthy volunteers

Hepcidin regulates plasma iron bioavailability and subsequently iron availability for erythropoiesis. rHuEPO has been reported to decrease hepcidin expression in case of repeated subcutaneous injections. Thus, hepcidin level measurement could be a candidate marker for detection of rHuEPO abuse. However, when used for doping, rHuEPO can be injected intravenously and the scheme of injection is unknown. Our aim was to evaluate the early effects of a single intravenous rHuEPO injection on serum hepcidin levels. Fourteen male healthy volunteers received one intravenous injection of 50 U/Kg of rHuEPO during a placebo-controlled, randomized, double-blind, cross-over study. Serum hepcidin, quantified by a competitive ELISA method and iron parameters was then evaluated for 24 h. Serum levels of hepcidin were significantly increased 4 h after rHuEPO injection when compared with placebo injection (78.3 ± 55.5 vs. 57.5 ± 34.6 ng/ml, respectively; +36%, p < 0.05), whereas iron and transferrin saturation dramatically decreased 12 h after rHuEPO injection when compared with placebo injection (9.2 ± 3.5 vs. 15.8 ± 4.2 μg/l, respectively; -42%, p < 0.05 and 14.8 ± 5.0 vs. 26.3 ± 6.4%, respectively; -44%, p < 0.05). In addition, 12 and 24 h after rHuEPO injection serum hepcidin levels were lower compared with placebo injection (41.6 ± 27.4 vs. 56.6 ± 28.1 ng/ml after 12 h; -27%, p < 0.05 and 26.0 ± 29.6 vs. 81.2 ± 29.4 ng/ml after 24 h; -68%, p < 0.05). Intravenous injection of recombinant EPO induces a precocious and transient increase of serum hepcidin leading to a transient decrease of iron bioavailability. The transitory increase and dynamics of its concentration make difficult the practical use of hepcidin to detect rHuEPO doping.

Liver iron overload is associated with elevated SHBG concentration and moderate hypogonadotrophic hypogonadism in dysmetabolic men without genetic haemochromatosis

AIMS

To assess the relation between moderate iron overload on sex hormone binding globulin (SHBG) levels and gonadotroph function in men with dysmetabolic iron overload syndrome and the effects of phlebotomy.

METHODS

The relationship between magnetic resonance imaging assessed liver iron concentration (LIC) and plasma ferritin levels with total testosterone, bioavailable testosterone (BT), SHBG and LH levels, were studied in 50 men with moderate dysmetabolic iron excess, in the absence of genetic haemochromatosis, who were randomised to phlebotomy therapy or to normal care.

RESULTS

Four patients (8%) had low total testosterone (<10.4 nmol/l) and 13 patients (26%) had low BT (<2.5 nmol/l). In the entire population, those with LIC above the median (90 μmol/l) had a higher mean SHBG (P=0.028), lower LH (P=0.039) than those with LIC below the median. In multivariable analysis (adjusted for age, and fasting insulin) LIC was significantly associated with SHBG (positively) and LH (negatively). Patients in the highest quartile of SHBG had higher LIC (P=0.010) and higher ferritinaemia (P=0.012) than those in the three other quartiles. Iron depletion by venesection did not significantly improve any hormonal levels.

CONCLUSIONS

Hypogonadism is not infrequent in men with dysmetabolic iron overload syndrome. Liver iron excess is associated with increased plasma SHBG and moderate hypogonadotrophic hypogonadism. Phlebotomy therapy needs further investigation in symptomatic hypogonadal men with dysmetabolic iron excess.

Vitamin D deficiency, vitamin D receptor gene polymorphisms and cardiovascular risk factors in Caribbean patients with type 2 diabetes

AIM

The prevalence of diabetes in the French West Indies is three times higher than in mainland France. We aimed to assess the associations between vitamin D deficiency, vitamin D receptor (VDR) gene polymorphisms and cardiovascular risk factors in Caribbean patients with type 2 diabetes (T2D).

METHODS

In this cross-sectional study of 277 patients, 25-hydroxyvitamin D was measured by radioimmunoassay. FokI, BsmI, ApaI and TaqI single nucleotide polymorphisms (SNPs) of the VDR gene were genotyped. Analysis of covariance and logistic regression were performed.

RESULTS

The study included 76 patients of Indian descent and 201 patients of African descent. The prevalence of vitamin D deficiency (<20 ng/mL) was 42.6%. When patients were classified into groups with (G1) and without (G2) vitamin D deficiency, there were no significant differences in age, systolic blood pressure, low-density lipoprotein cholesterol and HbA(1c), although body mass index was significantly higher in G1. Vitamin D deficiency was significantly associated with increased diastolic blood pressure and triglyceride levels, and reduced high-density lipoprotein cholesterol (P<0.05). Prevalence of vitamin D deficiency was decreased in patients carrying the f allele of FokI (OR: 0.52; P=0.02) and the aa genotype of ApaI (OR: 0.46; P=0.05). BsmI and TaqI SNPs were not associated with vitamin D deficiency.

CONCLUSION

The rate of vitamin D deficiency was high in our T2D patients, and was associated with the VDR gene FokI and ApaI polymorphisms and cardiovascular risk profile. Measurements of vitamin D may help to detect T2D patients with cardiovascular risk, and VDR polymorphisms might explain why vitamin D deficiency is so frequently seen in some T2D patients.

Specific molecular and cellular events induced by irradiated X-ray photoactivatable drugs raise the problem of co-toxicities: particular consequences for anti-cancer synchrotron therapy

Synchrotrons are capable of producing intense low-energy X-rays that enable the photoactivation of high-Z elements. Photoactivation therapy (PAT) consists of loading tumors with photoactivatable drugs and thereafter irradiating them at an energy, generally close to the K-edge of the element, that enhances the photoelectric effect. To date, three major photoactivatable elements are used in PAT: platinum (cisplatin and carboplatin), iodine (iodinated contrast agents and iododeoxyuridine) and gadolinium (motexafin gadolinium). However, the molecular and cellular events specific to PAT and the radiobiological properties of these photoactivatable drugs are still misknown. Here, it is examined how standard and synchrotron X-rays combined with photoactivatable drugs impact on the cellular response of human endothelial cells. These findings suggest that the radiolysis products of the photoactivatable drugs may participate in the synergetic effects of PAT by increasing the severity of radiation-induced DNA double-strand breaks. Interestingly, subpopulation of highly damaged cells was found to be a cellular pattern specific to PAT. The data show that the efficiency of emerging anti-cancer modalities involving synchrotron photoactivation strongly depends on the choice of photoactivatable drugs, and important series of experiments are required to secure their clinical transfer before applying to humans.

Type B mandibuloacral dysplasia with congenital myopathy due to homozygous ZMPSTE24 missense mutation

Mutation in ZMPSTE24 gene, encoding a major metalloprotease, leads to defective prelamin A processing and causes type B mandibuloacral dysplasia, as well as the lethal neonatal restrictive dermopathy syndrome. Phenotype severity is correlated with the residual enzyme activity of ZMPSTE24 and accumulation of prelamin A. We had previously demonstrated that a complete loss of function in ZMPSTE24 was lethal in the neonatal period, whereas compound heterozygous mutations including one PTC and one missense mutation were associated with type B mandibuloacral dysplasia. In this study, we report a 30-year longitudinal clinical survey of a patient harboring a novel severe and complex phenotype, combining an early-onset progeroid syndrome and a congenital myopathy with fiber-type disproportion. A unique homozygous missense ZMPSTE24 mutation (c.281T>C, p.Leu94Pro) was identified and predicted to produce two possible ZMPSTE24 conformations, leading to a partial loss of function. Western blot analysis revealed a major reduction of ZMPSTE24, together with the presence of unprocessed prelamin A and decreased levels of lamin A, in the patient's primary skin fibroblasts. These cells exhibited significant reductions in lifespan associated with major abnormalities of the nuclear shape and structure. This is the first report of MAD presenting with confirmed myopathic abnormalities associated with ZMPSTE24 defects, extending the clinical spectrum of ZMPSTE24 gene mutations. Moreover, our results suggest that defective prelamin A processing affects muscle regeneration and development, thus providing new insights into the disease mechanism of prelamin A-defective associated syndromes in general.

Biological and hemodynamic effects of low doses of fludrocortisone and hydrocortisone, alone or in combination, in healthy volunteers with hypoaldosteronism

Low doses of hydrocortisone (HC) and fludrocortisone (FC) administered together improve the prognosis after septic shock; however, there continues to be disagreement about the utility of FC for this indication. The biological and hemodynamic effects of HC (50 mg intravenously) and FC (50 microg orally) were assessed in 12 healthy male volunteers with saline-induced hypoaldosteronism in a placebo-controlled, randomized, double-blind, crossover study performed according to a 2 x 2 factorial design. HC and FC significantly decreased urinary sodium and potassium levels (from -58% at 4 h to -28% at 10 h and from -35% at 8 h to -24% at 12 h, respectively) with additive effects. At 4 h after administration, HC significantly increased cardiac output (+14%), decreased systemic vascular resistances (-14%), and slightly increased heart rate (+4 beats/min), whereas FC had no hemodynamic effect. At doses used in septic shock, HC induced greater mineralocorticoid effect than FC did. HC also induced transient systemic hemodynamic effects, whereas FC did not. New studies are required to better define the optimal dose of FC in septic shock.

Species specific thyroid signal transduction: conserved physiology, divergent mechanisms

In the literature, data obtained in signal transduction from various species thyroids and cells lines are often integrated in a common model. We investigate qualitatively and systematically, using the same protocol, the control by TSH of the two main functions of the thyrocytes, the synthesis and the secretion of thyroid hormones. In all species investigated, the TSH receptor activates both. In some species, including humans, rats and mice, the TSH receptor activates both the cAMP and phospholipase C-PIP2 cascades, in others (e.g. dog) it only stimulates the first. The cAMP pathway activates the limiting step in thyroid hormones synthesis, the generation of H(2)O(2), in dog, rat and mice but not in human, pig, horse and beef. Thus although the physiological result of TSH action is the same in all species, the signaling pathways used are different. Other distinctions in signaling are observed such as the relative effects of one cascade on the other.

H2O2, signal, substrate, mutagen and chemorepellent from physiology to biochemistry and disease

The history of the study by our group of the generation, the role and the effects of H2O2 in the thyroid, is summarized. The relations with thyroid diseases are discussed: myxedematous cretinism, thyroiditis, thyroid cancer, congenital hypothyroiddism, are discussed. A new role of H2O2 in the chemorepulsion of bacteria is proposed.

Consequences of thebleed-throughphenomenon in immunofluorescence of proteins forming radiation-induced nuclear foci

PURPOSE

By allowing the visualization of the proteins inside cells, the immunofluorescence technique has revolutionized our view of events that follow radiation response. Particularly, the formation of nuclear foci, their kinetic of appearance and disappearance, and the association-dissociation of protein partners are useful endpoints to better understand the effects of ionizing radiation. Recently, the technique based on the phosphorylation of the histone 2A family, member X (H2AX) has generated a plethora of reports concerning the interaction between the major proteins involved in DNA repair and stress signaling pathways. However, some unavoidable overlaps of excitation and emission wavelength spectra (the so-called bleed-through phenomenon) of the available fluorescent markers are still generating discrepancies and misinterpretations in the choreography of DNA damage response. Biases are particularly strong with the fluorescein isothiocyanate (FITC)-rhodamine couple, tetramethyl rhodamine iso-thiocyanate (TRITC), the most extensively used markers.

METHOD AND RESULTS

Here, two representative examples of biased co-immunofluorescence with pH2AX proteins that form radiation-induced nuclear foci or not are presented. A brief review of literature points out differences in kinetic of appearance and association-dissociation of radiation-induced pH2AX and MRE11 foci.

CONCLUSION

Through this report, we would like authors to consider more carefully protein co-localizations by performing systematically, before any co-immunofluorescence, immunofluorescence of each protein separately to avoid bleed-through artifacts.

Clinical value of M22-based assays for TSH-receptor antibody (TRAb) in the follow-up of antithyroid drug treated Graves' disease: comparison with the second generation human TRAb assay

BACKGROUND

We compared the clinical performances of two new M22-based assays for TSH-receptor antibody (TRAb) with those of the human TRAb assay (hTRAK) in Graves' disease patients at the end of treatment.

PATIENTS AND METHODS

Sera were obtained from 128 Graves' patients treated for 18 months with antithyroid drugs. Sixty-six remained in remission and sixty-two had relapse of hyperthyroidism in a 3-year follow-up after discontinuing treatment. TRAbs were measured using two M22-based methods (electrochemiluminescence using the Cobas or ELISA using the Medizym TRAb clone) and with the hTRAK.

RESULTS

At T18, the results were significantly higher by the Cobas assay (median: 2.7 IU/L, range: 1.1-18.5 IU/L) or lower by ELISA (median: 0.56 IU/L, range: 0.22-14.8 IU/L) than those obtained for the hTRAK (median: 1.5 IU/L, range: 0.9-9.8 IU/L). The use of cut-off limits at 1.9 IU/L, 3.2 IU/L and 0.94 IU/L gave similar and higher prevalences of TRAb-positive patients in the group of relapse as compared to the remission group. However, some patients remained misclassified in each remission or relapse group.

CONCLUSIONS

The M22-based TRAb assays did not improve the predictive value of relapse obtained with the hTRAK measured at the end of treatment. High inter-method variability requires assay harmonization for correct interpretation of results.

Intermethod Variability in TSH-Receptor Antibody Measurement: Implication for the Diagnosis of Graves Disease and for the Follow-Up of Graves Ophthalmopathy

Background: We compared the analytical and clinical performance of 3 porcine thyroid receptor antibody (TRAb) methods (1 second- and 2 new third-generation systems) with the conventional TRAb assay based on the human recombinant TSH receptor (hTRAK).

Patients and Methods: We obtained sera from 86 patients with untreated Graves disease (GD) and 71 healthy controls. We measured TRAb concentrations by radioreceptor assay using the hTRAK (Brahms) or the porcine TSH receptor (pRRA) from Beckman-Coulter, by electrochemiluminescence immunoassay (ECLIA) with the Elecsys/Cobas (Roche), and by ELISA using the Medizym TRAb clone (Medipan).

Results: Between-run assay imprecision was ≤10% and ≤7.6% for hTRAK and ECLIA, but reached 14% and 14.9% for ELISA and pRRA, respectively. Maximal specificity and sensitivity close to 100% were obtained for hTRAK, ECLIA, and ELISA. pRRA failed to detect positive TRAbs in 5 GD patients. Although calibrated against the same reference standard 90/672, the assays displayed a high intermethod variability. The results were significantly higher by ECLIA and lower by ELISA and pRRA compared with hTRAK. Patients with ophthalmopathy had higher TRAb results by ELISA and pRRA than those without eye disease.

Conclusions: Second- and third-generation TRAb assays had similar diagnostic sensitivities in the diagnostic evaluation of GD. Despite the use of the same reference standard for calibration, high intermethod variability in TRAb assay results was seen in untreated GD patients. Assay harmonization is necessary for correct interpretation in the follow-up of Graves ophthalmopathy.

Parallel assessment of male reproductive function in workers and wild rats exposed to pesticides in banana plantations in Guadeloupe

BACKGROUND

There is increasing evidence that reproductive abnormalities are increasing in frequency in both human population and among wild fauna. This increase is probably related to exposure to toxic contaminants in the environment. The use of sentinel species to raise alarms relating to human reproductive health has been strongly recommended. However, no simultaneous studies at the same site have been carried out in recent decades to evaluate the utility of wild animals for monitoring human reproductive disorders. We carried out a joint study in Guadeloupe assessing the reproductive function of workers exposed to pesticides in banana plantations and of male wild rats living in these plantations.

METHODS

A cross-sectional study was performed to assess semen quality and reproductive hormones in banana workers and in men working in non-agricultural sectors. These reproductive parameters were also assessed in wild rats captured in the plantations and were compared with those in rats from areas not directly polluted by humans.

RESULTS

No significant difference in sperm characteristics and/or hormones was found between workers exposed and not exposed to pesticide. By contrast, rats captured in the banana plantations had lower testosterone levels and gonadosomatic indices than control rats.

CONCLUSION

Wild rats seem to be more sensitive than humans to the effects of pesticide exposure on reproductive health. We conclude that the concept of sentinel species must be carefully validated as the actual nature of exposure may varies between human and wild species as well as the vulnerable time period of exposure and various ecological factors.

Variation in serum and plasma PTH levels in second-generation assays in hemodialysis patients: a cross-sectional study

BACKGROUND

Previous reports show that parathyroid hormone (PTH) concentrations may vary widely depending on the assay used to assess PTH. In this cross-sectional study, we aim to determine the usefulness of standardizing blood handling for optimal interpretation of PTH in patients with chronic kidney disease.

STUDY DESIGN

Diagnostic test study.

SETTING & PARTICIPANTS

Predialysis blood was sampled in 34 long-term hemodialysis patients at a single academic medical center.

INDEX TEST

PTH was measured by using 6 different automated second-generation assays (Elecsys, Advia Centaur, LIAISON, Immulite, Architect, and Access assays), 3 blood specimen types (serum, EDTA plasma, and citrate plasma), and 2 consecutive days of measurement (after thawing and 18 hours later with samples having been let at room temperature).

REFERENCE TEST

None.

RESULTS

A mixed statistical analysis model showed that the nature of the assay (P < 0.001) and nature of the blood sample (P < 0.001) significantly influenced variability in PTH concentrations, whereas day of measurement (day 1 or 2) did not (P = 0.5). Most PTH variability was caused by observations (96.8%), then manufacturer's kit (2.5%), and last, specimen type (0.7%). PTH concentrations measured in citrate plasma were lower with every assay method used than those observed in serum or EDTA plasma. The interaction between manufacturer and specimen type was of moderate statistical significance (P = 0.04). To evaluate the potential clinical consequence of PTH measure variability, we classified patients according to Kidney Disease Outcomes Quality Initiative cutoff values (PTH < 150 pg/mL; PTH, 150 to 300 pg/mL; and PTH > 300 pg/mL). Overall, statistical classification agreement was moderate to high for comparison between assays and high to very high between different blood samples and between days of measurement. However, we found that up to 11 of 34 patients were classified in different categories with some assays (LIAISON versus Architect) and up to 7 of 34 in different categories with different blood specimen type (citrate plasma versus serum [corrected] in LIAISON assay).

LIMITATIONS

This is a cross-sectional study that used single lots of reagents. There currently is no reference method for the measurement of PTH and no recombinant PTH standard for PTH assay.

CONCLUSION

PTH variability caused by the nature of the assay and/or blood specimen type is large enough to potentially influence clinical decision making. A specified collection method therefore should be used for PTH measurements. In routine practice, we recommend serum PTH over EDTA or citrate plasma.

Elevated parathyroid hormone 44-68 in idiopathic calcium pyrophosphate dihydrate crystal deposition disease. Role of menopause and iron metabolism?

OBJECTIVE

To examine whether idiopathic calcium pyrophosphate dihydrate (CPPD) crystal deposition disease (CDD) is related to altered parathyroid hormone (PTH) metabolism.

METHODS

Forty-two patients with idiopathic CPPD CDD were compared with 67 controls, 33 of whom were matched for age and sex.

RESULTS

Serum PTH 44-68 concentrations were elevated in 29% of patients and were significantly higher in the patients than in their sex- and age-matched controls (Z = -4.664, p < 0.0001). PTH 1-84 levels were normal. Serum calcium, phosphorus, and ferritin levels were normal, but were significantly higher in the patients. Serum PTH 44-68 levels correlated negatively with serum transferrin in female controls aged >or= 45 years, and with transferrin saturation in the female patients. Correlation between serum ferritin and age was linear and positive in the former subjects and quadratic in the latter.

CONCLUSION

Elevated serum concentration of PTH mid-fragments containing the 44-68 region could explain the joint disorders associated with idiopathic CPPD CDD, as shown in genetic hemochromatosis. In female patients the elevation of PTH mid-fragments could be linked to changes in iron metabolism provoked by the menopause.

Determination of interferon beta neutralizing antibodies in multiple sclerosis: improvement of clinical sensitivity of a cytopathic effect assay

INTRODUCTION

Neutralizing antibodies (NAb) against interferon beta (IFNbeta) reduce treatment efficacy in patients with multiple sclerosis (MS).

OBJECTIVE

We used the cross-reactivity of NAbs against IFNbeta-1a or IFNbeta-1b for improving the sensitivity of NAb measurement.

PATIENTS/METHODS

The study included sera from 185 MS patients treated at least 12 months (T1) with IFNbeta-1a (Rebif; n=62 or Avonex; n=61) or IFNbeta-1b (Betaferon; n=62). NAbs were measured by CPE in all the sera using the WISH cell line infected by the bovine stomatitis vesicular virus. NAb titres were expressed in ten-fold reduction (TRU)/mL. NAb-positive titres at T1 were also measured 3 to 6 months later (T2).

RESULTS

At T1, with the classical CPE assay using the IFNbeta type (1a or 1b) according to the molecule administered, 29/180 (15.7%) patients had positive NAb titres: 9/62 (14.5%), 14/62 (22.6%) and 6/61 (9.8%) subjects were treated with Betaferon, Rebif and Avonex, respectively. When IFNbeta-1a (Rebif or Avonex) was used, NAb-positive results were found in 33/185 (17.8%) patients. They included the 29 patients previously found positive with the classical CPE method and 7 other subjects treated with Betaferon and NAb-negative against IFNbeta-1b. All the 33 NAb-positive patients at T1 were positive 3 to 6 months later.

CONCLUSION

IFNbeta-1a should be used for the NAb determination for an optimal evaluation of NAb-positive patients in MS patients treated with IFNbeta.

Restoration of ovulation after unilateral ovariectomy in a woman with McCune-Albright syndrome: a case report

INTRODUCTION

McCune-Albright syndrome (MAS) is characterized by peripheral precocious puberty, café-au-lait spots, and polyostotic fibrous dysplasia. This syndrome is due to a post-zygotic mutation of the GNAS1 gene with mosaic distribution and unilateral predominance. Clinical manifestations depend on the tissues carrying the mutation. We describe the ovarian function before and after unilateral ovariectomy in a woman with MAS and bilateral distribution of the GNAS1 gene mutation.

CASE REPORT

A 33-year-old patient, previously diagnosed as having MAS, presented irregular menstrual cycles (30-180 days) and monophasic temperature curves. Transvaginal ultrasound and blood tests were repeated at 3-day intervals over 3 months. Findings included a persistent quiescent left ovary, a persistent polycystic right ovary, constantly high estradiol-17beta (E2) levels, and very low FSH and LH levels. She also presented severe persistent pelvic pain. Because of unilateral ovarian activity, a unilateral right ovariectomy was performed as well as biopsy of the remaining left ovary. A GNAS1 gene mutation was identified in both ovaries. A regular monthly menstrual cycle was immediately restored. On day 3 of the menstrual cycle, E2 level was 30 pg/ml, FSH level was 7.5 mIU/ml, and LH level was 6.4 mIU/ml. On day 17, pelvic ultrasound showed one follicle of 25 mm in the left ovary. On day 21, the progesterone level was 13.1 ng/ml.

DISCUSSION

This is the first report of ovulation being restored following unilateral ovariectomy in an adult patient suffering from severe MAS with GNAS1 gene mutation identified in both ovaries.