Use of the parathyroid hormone assay at H6 post thyroidectomy: an early predictor of hypocalcemia.

PURPOSE: Hypocalcemia linked to a diminished circulating intact parathormone (iPTH) is the most common complication after total thyroidectomy. The objective of this study was to evaluate iPTH as a predictor of post-thyroidectomy hypocalcemia. METHODS: Hundred-and-eight patients who underwent total thyroidectomy were included. Blood samples (iPTH, calcium and albumin) were performed at different times: preoperatively (H0), after removal of the gland (Hdrop), 6 h (H6) and one day (D1) after the surgery. Hypocalcemia was defined by total calcium corrected by serum albumin ≤ 2.10 mmol/l. The area under the ROC curve (AUC) was used to determine the best cut-off value and predictability of iPTH for hypocalcemia in terms of absolute value (ng/L), decrease in the slope (ng/L) and decline (%) between two times. RESULTS: The study included 101 patients. Among them, 39 had hypocalcemia (38.6%). At H6, an iPTH absolute value less than 14.35 ng/L (Se = 0.706; Sp = 0.917) and a decline from the preoperative time of more than 59.5% (Se = 0.850; Sp = 0.820) were predictive of hypocalcemia. Other absolute values, decrease in the sloop and decline between preoperative and postoperative values were less relevant. CONCLUSION: The iPTH 6 h after total thyroidectomy is predictive of hypocalcemia. It might be used to identify patients not at risk of hypocalcemia and earlier discharge could be considered.

Evaluation of the performance of ultrasonography and 99mTc-sestamibi scintigraphy for primary hyperparathyroidism surgery.

INTRODUCTION: Minimally invasive surgery has become the standard surgical attitude in primary hyperparathyroidism. It requires precise preoperative lesion localization. The aim of the present study was to evaluate the performance of ultrasonography and 99mTc-sestamibi scintigraphy in minimally invasive surgery for primary hyperparathyroidism. MATERIALS AND METHODS: A retrospective study included all patients managed surgically for primary hyperparathyroidism between January 2008 and November 2017 in the University Hospital of Brest (France). Two hundred and seventy-three patients underwent ultrasonography and 99mTc-sestamibi scintigraphy. Results determined intrinsic (sensitivity and specificity) and extrinsic (positive and negative predictive values) performance on per-patient and per-gland analysis. Demographic, preoperative, interventional and cure data were compared according to ultrasonography and scintigraphy results, distinguishing 3 patient groups: concordant n=156, discordant n=99, negative n=18. RESULTS: On per-gland analysis, sensitivity was 70% for ultrasound, 74% for 99mTc-sestamibi scintigraphy and 81% for associated ultrasound-scintigraphy; positive predictive values were 89%, 91% and 96%, respectively. Gland volume and concomitant thyroid pathology rates differed significantly (both p=0.003) between the 3 imaging results groups. CONCLUSION: The performance of associated ultrasound-99mTc-sestamibi-scintigraphy provided a positive predictive value of 96%. Combining the two techniques reduced surgical morbidity.

[Subclinical adrenal diseases: silent pheochromocytoma and subclinical Addison's disease]. / Maladies surrénaliennes infracliniques: cas du phéochromocytome silencieux et de la maladie d'Addison infra-clinique.

The silent pheochromocytoma, a hidden form of pheochromocytoma, exposes the patient to an increased risk of mortality if the diagnosis is not established on time. Biological diagnosis of pheochromocytoma can be difficult. Catecholamine secretion is dependent on tumor size and a large number of physiological, pharmacological, lifestyle modifications and sampling conditions influence the measurement of urinary and plasma metanephrines. The prevalence of pheochromocytoma is 2% among adrenal incidentaloma smaller than 3 cm (2/3 of tumors). Recent studies suggest the almost zero risk of pheochromocytoma among these tumors if they are hypodense (<10 housefield units) on adrenal tomography. Addison's disease is a pathology affecting about 1 in 8000. Immunopathology is still unknown, but some elements advocated the hypothesis of a predominant cell-mediated immunity in particular Interferon-gamma production by CD4 T lymphocytes in the presence of an epitope from the 21-hydroxylase, as well as IgG1 subtype produced by activated B lymphocytes, autoantibodies do appear to be a simple marker of the disease. Subclinical Addison's disease is defined by the presence of anti-21-hydroxylase autoantibodies, without clinical symptoms. It evolves faster to the clinical phase in young subjects, male, having high levels of autoantibodies and with an initially impaired adrenal function. Dosage of ACTH, plasma renin active, and basal cortisol and after Synacthen allow to discriminate the subjects with low or high risk of evolution and establish an appropriate monitoring.

Inhibition of peroxisome-proliferator-activated receptor (PPAR)alpha by MK886.

Although MK886 was originally identified as an inhibitor of 5-lipoxygenase activating protein (FLAP), recent data demonstrate that this activity does not underlie its ability to induce apoptosis [Datta, Biswal and Kehrer (1999) Biochem. J. 340, 371--375]. Since FLAP is a fatty-acid binding protein, it is conceivable that MK886 may affect other such proteins. A family of nuclear receptors that are activated by fatty acids and their metabolites, the peroxisome-proliferator-activated receptors (PPARs), have been implicated in apoptosis and may represent a target for MK886. The ability of MK886 to inhibit PPAR-alpha, -beta and -gamma activity was assessed using reporter assay systems (peroxisome-proliferator response element--luciferase). Using a transient transfection system in monkey kidney fibroblast CV-1 cells, mouse keratinocyte 308 cells and human lung adenocarcinoma A549 cells, 10--20 microM MK886 inhibited Wy14,643 activation of PPAR alpha by approximately 80%. Similar inhibition of PPAR alpha by MK886 was observed with a stable transfection reporter system in CV-1 cells. Only minimal inhibitory effects were seen on PPAR beta and PPAR gamma. MK886 inhibited PPAR alpha by a non-competitive mechanism as shown by its effects on the binding of arachidonic acid to PPAR alpha protein, and a dose-response study using a transient transfection reporter assay in COS-1 cells. An assay assessing PPAR ligand-receptor interactions showed that MK886 prevents the conformational change necessary for active-complex formation. The expression of keratin-1, a protein encoded by a PPAR alpha-responsive gene, was reduced by MK886 in a culture of mouse primary keratinocytes, suggesting that PPAR inhibition has functional consequences in normal cells. Although Jurkat cells express all PPAR isoforms, various PPAR alpha and PPAR gamma agonists were unable to prevent MK886-induced apoptosis. This is consistent with MK886 functioning as a non-competitive inhibitor of PPAR alpha, but may also indicate that PPAR alpha is not directly involved in MK886-induced apoptosis. Although numerous PPAR activators have been identified, the results show that MK886 can inhibit PPAR alpha, making it the first compound identified to have such an effect.

Activators of peroxisome proliferator-activated receptor-alpha partially inhibit mouse skin tumor promotion.

Several recent reports have suggested that peroxisome proliferator-activated receptors (PPARs) may be involved in the development of neoplasias in different tissue types. The present study was undertaken to determine whether PPARs play a role in skin physiology and tumorigenesis. In an initiation-promotion study, SENCAR mice treated topically with the PPARalpha ligands conjugated linoleic acid and 4-chloro-6-(2,3-xylidino)-2-pyrimidinylthioacetic acid (Wy-14643) exhibited an approximately 30% lower skin tumor yield compared with mice treated with vehicle. The PPARgamma and PPARdelta activators troglitazone and bezafibrate, respectively, exerted little, if any, inhibitory activity. PPARalpha was detected in normal and hyperplastic skin and in papillomas and carcinomas by immunohistochemistry. In addition, PPARalpha, PPARdelta/PPARbeta, and PPARgamma protein levels were analyzed by immunoblotting in normal epidermis and papillomas. Surprisingly, the levels of all three isoforms were increased significantly in tumors as opposed to normal epidermis. In primary keratinocyte cultures, protein levels of PPARalpha and, to a lesser extent, PPARgamma were markedly increased when the cells were induced to differentiate with high-calcium (0.12 mM) conditions. In addition, we observed that Wy-14643 enhanced transcriptional activity of a peroxisome proliferator-response element-driven promoter in a mouse keratinocyte cell line. These results demonstrate that keratinocytes express functional PPARalpha, that PPARalpha may play a role in differentiation, and that ligands for PPARalpha are moderately protective against skin tumor promotion. We conclude that selective PPARalpha ligands may exert their protective role against skin tumor promotion by ligand activation of PPARalpha.

8S-lipoxygenase products activate peroxisome proliferator-activated receptor alpha and induce differentiation in murine keratinocytes.

To determine the function and mechanism of action of the 8S-lipoxygenase (8-LOX) product of arachidonic acid, 8S-hydroxyeicosatetraenoic acid (8S-HETE), which is normally synthesized only after irritation of the epidermis, transgenic mice with 8-LOX targeted to keratinocytes through the use of a loricrin promoter were generated. Histological analyses showed that the skin, tongue, and stomach of transgenic mice are highly differentiated, and immunoblotting and immunohistochemistries of skin showed higher levels of keratin-1 expression compared with wild-type mice. The labeling index, however, of the transgenic epidermis was twice that of the wild-type epidermis. Furthermore, 8S-HETE treatment of wild-type primary keratinocytes induced keratin-1 expression. Peroxisome proliferator activated receptor alpha (PPARalpha) was identified as a crucial component of keratin-1 induction through transient transfection with expression vectors for PPARalpha, PPARgamma, and a dominant-negative PPAR, as well as through the use of known PPAR agonists. From these studies, it is concluded that 8S-HETE plays an important role in keratinocyte differentiation and that at least some of its effects are mediated by PPARalpha.

Peroxisome proliferator-activated receptors: a family of lipid-activated transcription factors.

Peroxisome proliferator-activated receptors (PPARs) are a family of nuclear transcription factors that belong to the steroid receptor superfamily. This family of PPARs includes PPARalpha, PPARdelta, PPARgamma1, and PPARgamma2. These PPARs are related to the T3 and vitamin D(3) receptors and bind to a hexameric direct repeat as a heterodimeric complex with retinoid receptor Xalpha. PPARs regulate the expression of a wide array of genes that encode proteins involved in lipid metabolism, energy balance, eicosanoid signaling, cell differentiation, and tumorigenesis. A unique feature of these steroid-like receptors is that the physiologic ligands for PPARs appear to be fatty acids from the n-6 and n-3 families of fatty acids and their respective eicosanoid products. This review describes the characteristics, regulation, and gene targets for PPARs and relates their effects on gene expression to physiologic outcomes that affect lipid and glucose metabolism, thermogenesis, atherosclerosis, and cell differentiation.

A novel 3T3-L1 preadipocyte variant that expresses PPARgamma2 and RXRalpha but does not undergo differentiation.

This report describes a novel adipocyte-like cell line termed 3T3-L1/RB1 that was derived from preadipocyte cell line, 3T3-L1. The 3T3-L1/RB1 cells continued to divide after reaching confluence, formed foci, and constitutively expressed a low level of adipose fatty acid binding protein (A-FABP) mRNA. However, 3T3L-1/RB cells did not undergo terminal differentiation as indicated by the failure of insulin and thiazolidendiones to induce the expression of A-FABP, lipoprotein lipase, and fatty acid synthase. We hypothesized that the 3T3-L1/RB1 variant did not respond to differentiation stimuli because it did not express either peroxisomal proliferator activated receptor gamma2 (PPARgamma2) or its heterodimer partner, retinoid X receptor alpha (RXRalpha). Surprisingly, Western blots revealed that 3T3-L1/ RB1 cells contained both PPARgamma2 and RXRalpha proteins at levels equal to or greater than that of the parent cell line. However, gel retardation assays using the adipose response element from A-FABP and nuclear protein extracts from 3T3-L1/RB1 cells treated with insulin or pioglitazone revealed that nuclear protein extracts from 3T3-L1/RB1 cells had very little ability to bind the PPARgamma2 recognition sequence of the A-FABP gene. These data suggest that the 3T3-L1/RB1 variant contains a mutation that may prevent ligand activation of PPARgamma2, and the subsequent conversion of 3T3-L1/RB1 cells to mature fat cells.

Synthesis of epoxypropyloxy chromones and allyl hydroxy chromones and in vitro-in vivo activity on protoscoleces of Echinococcus multilocularis (Cestoda).

Derivatives with epoxypropyloxy, allyloxy and allyl hydroxychromone structures were synthesized and tested against protoscoleces of Echinococcus multilocularis. Compounds IV-IX were tested in vitro and compound VII proved the most active of them with, at 0.1 mmol.L-1, 98% dead protoscoleces in open vesicles after 24 hours and 80% in closed vesicles within 96 hours. Compound VII was tested in vivo on Meriones unguiculatus infested by Echinococcus multilocularis, but was found to be rather inactive.

Mutagens, N-nitroso compounds and their precursors in gastric juice from patients with and without precancerous lesions of the stomach.

This study examined whether elevated risk of gastric cancer is associated with high levels of total N-nitroso compounds (NOC), their precursors and nitrosation-dependent genotoxins in gastric juice (GJ). An improved method for quantifying total NOC was used and genotoxicity was assayed in E. coli. Results from patients (n = 210) with or without precancerous lesions of the stomach and living in three areas with up to 8-fold variations in gastric cancer risk (U.K., France, Colombia) were compared. The level of nitrite (range < 1-472 mumol/l) was found to increase with the pH of GJ from the three countries and was dependent on country of collection. The levels of NOC (range: < or = 0.01-8.0 mumol/l) in GJ were not affected by stomach histology and country of collection. NOC levels increased linearly with nitrite concentrations, but the slope of the regression line was greater for acidic GJ (pH < or = 4). These data together suggest that chemical nitrosation contributes at least as much as other nitrosation pathways to the intragastric formation of NOC. Acid-catalysed nitrosation of GJ in vitro increased the NOC concentration (range: 7-1332 mumol/l) up to several 1000-fold but this increase was not predictive of gastric cancer risk either by country or by stomach histology. After acid-catalysed nitrosation, direct genotoxicity (SOS-inducing potency) was significantly higher in GJ with original pH > 4 and highest in samples from Colombia. The results (a) provide no support that intragastric total NOC levels are elevated in subjects with precancerous stomach lesions or living in a high risk area for stomach cancer; (b) confirm that a high nitrite level and elevated pH in GJ are strongly associated, the level of nitrite being associated with precancerous stomach conditions only in Colombia; (c) reveal the presence of precursor compounds in GJ, that after nitrosation yield direct mutagens that probably contain NOC and other substances. As their concentrations were significantly higher in achlorhydric subjects and highest in Colombian patients, these data together provide support for a role of intragastrically formed nitrite-derived direct mutagens in gastric cancer aetiology.

MELAS syndrome with mitochondrial tRNA(Leu)(UUR) mutation: correlation of clinical state, nerve conduction, and muscle 31P magnetic resonance spectroscopy during treatment with nicotinamide and riboflavin.

We report a patient with mitochondrial encephalomyopathy, lactic acidosis, and strokelike episodes treated with riboflavin and nicotinamide for 18 months, during which time previously frequent encephalopathic spells ceased. To confirm clinical benefit, we withdrew treatment and monitored response with muscle 31P magnetic resonance spectroscopy (MRS) and sural nerve conduction studies. Of three prospectively chosen MRS variables, two changed coincidentally with clinical end points; phosphocreatine (PCr)/adenosine triphosphate recovery rates fell in parallel with sural nerve sensory amplitudes, and a drop in muscle bioenergetic efficiency (relationship of inorganic phosphate/PCr to the accelerating force of contracting muscle) coincided with development of encephalopathy. Investigations revealed a deficiency of respiratory complex I and mutation of the mitochondrial tRNA(Leu)(UUR). We suggest that a defective cellular energy state in mitochondrial disease may be partially treatable and that changes seen in appropriate muscle spectroscopy studies may parallel improvement in brain and peripheral nerve function.

Potential anti-echinococcal activity of alkylaminoethers.

Trans 2-phenoxy cyclohexanol ethers (IA, IIA, IIIA, IVA, VA, and VIA), the cyclohexanol analog (IB) and one coumarinic compound (IC) were obtained and their activity against Echinococcus multilocularis metacestodes was studied and compared with that of trifluoperazine (TFP). All of these compounds are analogous to IA and belong to three classes. Class A comprises trans 2-phenoxycyclohexanol aminoethers whose alkylaminoether group varies; compound VIA bears one more methylene in its aminoether group than does compound IA. Class B consists of one compound exhibiting no phenoxy function. Class C comprises one coumarinic analog. In vitro assays were performed using metacestodes whose protoscoleces were attached to the germinal layer in open and in closed vesicles. Compounds IA and IIA exhibited the highest activity, but it was lower than that displayed by TFP under the same conditions. Compound IA was tested in an in vivo assay in jirds (50 mg/kg/daily beginning at 80 days p.i.); it produced results that were analogous to those obtained using TFP without inducing the neuroleptic effect associated with the latter. After 40-90 days' treatment, the percentage of diminution in the entire parasitic mass in the jirds that survived minimal treatment (71%) was about 41% as compared with that in untreated jirds. Histologic examination of the parasites in treated jirds revealed numerous dead protoscoleces and some parasitic dedifferentiated cells. This parasitic response may indicate that in alveolar echinococcosis, these drugs exhibit only a parasitostatic effect.

N-nitroso compounds, genotoxins and their precursors in gastric juice from humans with and without precancerous lesions of the stomach.

We are investigating the interrelationships between levels of total N-nitroso compounds (NOC), genotoxic activity (both before and after nitrosation), degree of bacterial colonization in gastric juice and degree of severity or absence of precancerous lesions of the stomach. The mean level of constitutive total NOC in gastric juice was similar in the different groups of patients, but it was higher in acidic gastric juice (n = 30) than in gastric juice at pH greater than 4.5 (n = 12). Acid-catalysed nitrosation of gastric juice in vitro increased the concentration of total NOC by up to several thousand fold, to a maximum of 1330 mumol/l. Genotoxicity, expressed as SOS-inducing potency per 100 microliters of gastric juice was measurable in only 20% of gastric juice samples tested. After acid-catalysed nitrosation, however, all samples showed genotoxic activity, the mean SOS-inducing potency being four to seven times greater than the corresponding constitutive value. There was no association between the mean SOS-inducing potency of gastric juice and the severity of precancerous lesions. The mean SOS-inducing potency of neutral or basic gastric juice was slightly greater than that of acidic samples. In a kinetic study on N-nitrosation of gastric juice in vitro, a mixture of amino and amido substrates was nitrosated; both qualitative and quantitative individual differences in nitrosatable substrates in gastric juice were seen. Fractionation of acidic, neutral and basic nitrosated gastric juice samples revealed a preponderance of nonvolatile, unknown NOC with varying polarities. The results of our study suggest that only pH determines the nature and level of precursors of NOC and of nitrosation-dependent genotoxins in gastric juice.