Self-organizing behaviour of glycosteroidal bolaphiles: insights into lipidic microsegregation.

In this article we describe work on the synthesis of bolaphile biomimics composed of glucose head groups and steroidal units linked together by a methylene chain of varying length. The condensed phases formed by self-organization of the products as a function of temperature were characterized by differential scanning calorimetry and thermal polarized light microscopy. The results of these studies show that the thermal stabilities of the lamellar mesophases formed vary linearly as a function of increasing aliphatic composition, which reflects a linear hydrophobic-hydrophilic balance with respect to transition temperatures.

Thyroid cancer following nuclear tests in French Polynesia.

BACKGROUND: Between 1966 and 1974, France conducted 41 atmospheric nuclear tests in Polynesia, but their potential health effects have not previously been investigated. METHODS: In a case-control study, we compared the radiation exposure of almost all the French Polynesians diagnosed with differentiated thyroid carcinoma between 1981 and 2003 (n=229) to the exposure of 373 French Polynesian control individuals without cancer from the general population. Radiation exposures were estimated using measurements after the nuclear tests, age at time of each test, residential and dietary information. RESULTS: The average thyroid dose before 15 years of age was about 1.8 mGy, and 5% of the cases and 3% of the controls received a dose above 10 mGy. Despite this low level of dose, and after adjusting for ethnic group, level of education, body surface area, family history of thyroid cancer and number of pregnancies for women, we observed an increasing risk (P=0.04) of thyroid cancer with increasing thyroid dose received before age of 15 years, which remained after excluding non-aggressive differentiated thyroid micro-carcinomas. This increase of risk per unit of thyroid radiation dose was higher (P=0.03) in women who later experienced four or more pregnancies than among other women. CONCLUSION: The risk estimate is low, but is based on limited exposure data. The release of information on exposure, currently classified, would greatly improve the reliability of the risk estimation.

[New medical treatments for polycystic ovary syndrome]. / Les nouveaux traitements médicaux du syndrome des ovaries polykystiques.

Polycystic ovary syndrome (PCO) is a polygenic disease worsened by obesity and environmental factors. PCO is characterized by chronic menstrual irregularity and hypofertility and metabolic disorders. Routine care includes appropriate diet, exercise and annual check-up to search for high blood pressure. Laboratory tests should include a lipid profile and fasting serum glucose. Insulin sensitizing drugs improve the metabolic pattern, induce ovulation and increase pregnancy rate. Here, we review the different therapeutic options for these patients.

[Prolonged suppressive L-thyroxine therapy. Longitudinal study of the effect of LT4 on bone mineral density and bone metabolism markers in 71 patients]. / Traitement prolongé par L-thyroxine à visée suppressive. Etude longitudinale de l'influence de la LT4 sur la densité minérale osseuse et les marqueurs osseux métaboliques chez 71 patients.

OBJECTIVES: A prospective longitudinal study was conducted to investigate the influence of prolonged suppressive L-thyroxin therapy on bone density and biochemical markers of bone remodeling. PATIENTS AND METHODS: Seventy-one patients (including 28 menopaused women) taking long-term L-T4 for thyroid carcinoma were divided into 3 groups according to their TSH level: low (TSH < 0.04 mlU/l), moderate (0.04 TSH < or = 0.10 mlU/l) and high (TSH > 0.10 mlU/l). Bone density was measured in lumbar vertebrae annually for a mean 4.5 years. Bone metabolism markers were measured over a 4 year period. Bone density measurements of the femur were also obtained for 2 years in 16 menopaused women. RESULTS: Lumbar bone density did not decline whatever the TSH level or the duration of L-T4 treatment. Likewise for menopaused women without substitution estroprogesterone therapy. Over the 4 years, biochemical markers of bone formation, including bone alkaline phosphatases and osteocalcin, or of bone resorption, including urinary hydroxyprolin, did not vary. In addition, in menopaused women, femoral bone density was not significantly lowered over the 2 years follow-up. No lumbar or femoral osteopenia was observed in these patients taking L-thyroxin, even for those with complete TSH blockade. Biochemical markers did not demonstrate a significant acceleration of bone turnover during prolonged administration of L-T4 at suppressive levels.

Comparison of the analytical and clinical performances of three thyrotropin immunoassay kits.

We first compared the analytical performances in terms of precision of two different generation thyrotropin (TSH) assays: Amerlite TSH-60 Assay (K2-TSH) versus Berilux hTSH (B3-TSH) and Kodak Amerlite TSH-30 Ultrasensitive Assay (K3-TSH). Then, we compared the clinical performances in 69 thyrotropin-suppressed patients with thyroid cancer and in 17 other patients referred for newly diagnosed hyperthyroidism. All the patients were given 200 micrograms of Protirelin IV for TRH testing. At the analytical level, the functional detection limit (FDL) was 0.006, 0.017, and 0.04 mU/l for B3-, K3-, and K2-TSH, respectively. At the clinical level of the 17 hyperthyroid patients, 52.9% displayed a positive TRH test with B3, 5.9% with K3, and 11.8% with K2; besides, 29.4% had a basal TSH detectable value with B3, 5.9% with K3, and 11.8% with K2. Among the patients receiving suppressive therapy: 1) 95.6%, 49.3%, and 50.7% showed a detectable TSH response to TRH, with B3-TSH, K2-TSH, and K3-TSH, respectively, and 2) only 5.8% had undetectable basal TSH values with Berilux hTSH, versus 84% with K2 and 89.8% with K3. Considering our findings, we first conclude that third generation TSH assays (having a functional sensitivity limit between 0.01 and 0.02 mU/l) can be useful for monitoring patients on thyroxine suppressive therapy, so as to distinguish partial from more complete thyrotropin suppression. Secondly, even though K3 has a FDL consistent with a third generation TSH assay, it appears less clinically sensitive than B3. Yet, no current assay can thoroughly ascertain a state of overtreatment. Finally, it is important to routinely determine the FDL, which can vary from one kit to the other, within one generation of TSH assays. Indeed, B3 with a FDL at 0.006 mU/l is more useful for monitoring LT4-suppressed patients for thyroid cancer than K3 whose FDL is 0.017 mU/l.