[Necessity to define thyroid reference values for better clinical interpretation]. / De la nécessité de bien définir les valeurs de référence des hormones thyroïdiennes pour une meilleure interprétation clinique.

Discordances were observed with thyroid reference range from BCF Access 2 analyser. The purpose of this study was to establish specific reference range value for free thyroxine (FT4), free triiodothyronine (FT3) and thyrotropin (TSH) in adult Meaux Hospital population. Samples from 308 adults aged from 18 to 65 years were studied. Patients (no pregnancy and no iodine contrast media used) after informed consent, were exempted of thyroidal, cardiac, renal, multiple-organ-failure illnesses. Thyroid assays, anti-TPO and anti-TG levels were measured on the BCF Access2 immunoassay system. This work exposes difficulties to define range values in order to better use the biomarker in the clinical context.

[The level of evidence for the use of biomarkers in the early detection of prostate cancer]. / Les niveaux de preuve des biomarqueurs utilisés pour la détection précoce des cancers de la prostate.

To systematically review the evidence for the use of PSA and other biomarkers in the early detection of prostate cancer, we searched PubMed for clinical trials and studies assessing PSA and other biomarkers in the early detection of prostate cancer, published between 2000 and May 2013 that included >200 subjects. The level of evidence (LOE) for clinical utility was evaluated using the tumor marker utility grading system. A total of 84 publications, corresponding to 70 trials and studies were selected for inclusion in this review. We attributed a level of evidence (LoE) of IA to PSA for early PCa detection, but we do not recommend its use in mass screening. Emerging biomarkers were assessed in prospective case-control and cohort studies: PCA3 (n=3); kallikreins (n=3); [-2]proPSA (n=5); fusion oncogenes (n=2). These studies used biopsy results for prostate cancer to determine specificity and sensitivity, but they did not assess the effect on PCa mortality. The LoE attributed was III-C. PSA can be used for early prostate cancer detection but mass screening is not recommended. Studies on other biomarkers suggest that they could be used, individually or in combination, to improve the selection of patients with elevated PSA levels for biopsy, but RCTs assessing their impact on prostate cancer management and mortality are needed. A better use of available tests is possible for men at risk in order to maximize the risk-benefit ratio.

Growth hormone enhances fat-free mass and glutamine availability in patients with short-bowel syndrome: an ancillary double-blind, randomized crossover study.

BACKGROUND: Benefits of recombinant human growth hormone (rhGH) alone or combined with glutamine in patients with intestinal failure because of short-bowel syndrome remain controversial. OBJECTIVE: We explored effects of rhGH on whole-body protein metabolism in patients with short-bowel syndrome with intestinal failure (SBS-IF) to gain insight into its mechanism of action. DESIGN: Eight stable hyperphagic patients with severe SBS-IF received, in a double-blind, randomized crossover study, low-dose rhGH (0.05 mg · kg⁻¹ · d⁻¹) and a placebo for two 3-wk periods. Leucine and glutamine kinetics under fasting and fed conditions, fat-free mass (FFM), and serum insulin were determined on the final day of each treatment. RESULTS: rhGH increased FFM and nonoxidative leucine disposal (NOLD; an index of protein synthesis) (P < 0.02), whereas FFM and NOLD were correlated in the fed state (r = 0.81, P = 0.015). With rhGH administration, leucine release from protein breakdown (an index of proteolysis) decreased in the fed compared with fasting states (P = 0.012), which was not observed with the placebo. However, the fast-to-fed difference in leucine release from protein breakdown was not significantly different between rhGH and placebo (P = 0.093). With rhGH, the intestinal absorption of leucine and glutamine increased (P = 0.036) and correlated with serum insulin (r = 0.91, P = 0.002). rhGH increased glutamine de novo synthesis (P < 0.02) and plasma concentrations (P < 0.03) in both fasting and fed states. CONCLUSIONS: In SBS-IF patients, feeding fails to decrease proteolysis in contrast to what is physiologically observed in healthy subjects. rhGH enhances FFM through the stimulation of protein synthesis and might decrease proteolysis in response to feeding. Improvements in de novo synthesis and intestinal absorption increase glutamine availability over the physiologic range, suggesting that beneficial effects of rhGH in hyperphagic patients might be achieved without glutamine supplementation.

Taurine status and response to intravenous taurine supplementation in adults with short-bowel syndrome undergoing long-term parenteral nutrition: a pilot study.

Taurine deficiency in patients on long-term parenteral nutrition may be involved in cholestasis. We aimed to assess plasma taurine and tauro-conjugated bile acids in adults with short-bowel syndrome and their response to intravenous taurine. Thirty-two adult patients, who had been on taurine-free parenteral nutrition for a mean of 59 (SE 14) months for short-bowel syndrome, were studied retrospectively. In a second study, a subgroup of ten patients with chronic cholestasis received taurine-enriched (6.0 (SE 0.6) mg/kg per d) parenteral nutrition for 55 (SE 13) months. Post-absorptive plasma taurine and bile acid concentrations were measured and liver function tests routinely sampled. At baseline, plasma taurine was lower in patients with a jejunal length of less than 35 cm (group A, n 16) than in those with a jejunal length of 35 cm or more (group B, n 16): 43 (SE 3) v. 58 (SE 4) micromol/l (P=0.01). The groups were no different in terms of chronic cholestasis (12/16 v.13/16 patients), total bile acids (26 (SE 13) v.14 (SE 5) micromol/l) or the ratio of tauro-conjugated:glyco-conjugated bile acids (5 (SE 2) v.8(SE 4)%, usual range 30-60%). After supplementation, there was an increase in plasma taurine level (63 (SE 8) v. 43 (SE 4), P=0.007) but was no change in either total bile acids or the ratio of tauro-conjugated: glyco-conjugated bile acids. There was a significant decrease in aspartate aminotransferase level. Long-term parenteral nutrition for short-bowel syndrome is associated with an impaired tauro-conjugation of bile acids (enterohepatic pool), irrespective of plasma taurine level (systemic pool) and despite long-term taurine intravenous supplementation.

Hyperphagia contributes to the normal body composition and protein-energy balance in HIV-infected asymptomatic men.

Wasting can occur at an early stage of HIV infection. Both reduced energy intake and increased resting energy expenditure (REE) have been considered as factors in wasting with predominant lean body mass loss, suggesting disturbances of protein metabolism. Our aim was to study protein-energy metabolism in relation to body composition and oral energy intake in asymptomatic patients with HIV infection but receiving no active antiretroviral therapy. Stable-weight asymptomatic male patients (n = 8) at stage A of HIV infection with a detectable viral load were compared with 9 healthy control men. Protein metabolism was studied in the postabsorptive state using a primed constant infusion of l-[1-(13)C]leucine and l-[2-(15)N]glutamine. REE was studied by indirect calorimetry, body composition by bioelectrical impedance, and energy intake by dietary records. BMI and lean body mass did not differ between patients and controls. In HIV-infected subjects, energy intake, protein breakdown, protein synthesis, and REE were 57% (P < 0.05), 18% (P < 0.05), 22% (P < 0.05) and 14% (P < 0.05) greater than in controls, respectively. REE and protein breakdown were correlated (r = 0.73, P < 0.05). The hormonal profile was normal in HIV-infected subjects with the exception of low urinary C-peptide and plasma reverse triiodothyronine. Plasma interleukin-6 and tumor necrosis factor-alpha were greater than in controls, but energy intake was 1.53 times the REE in the HIV-infected men. Thus, at the asymptomatic stage of HIV infection, increased protein turnover contributes to the increase in the REE. Moderate hyperphagia, which occurred despite increased levels of cytokines, in conjunction with increased protein synthesis maintains a normal body composition, without significant loss of lean body mass.

Taurine kinetics assessed using [1,2-13C2]taurine in healthy adult humans.

To assess the dynamics of taurine metabolism in vivo, two sets of studies were carried out in healthy volunteers. First, pilot studies were carried in a single human subject to determine the time course of plasma and whole blood isotope enrichment over the course of an 8-h, unprimed continuous infusion of [1,2-(13)C(2)]taurine. Second, five healthy adult males received two tracer infusions on separate days and in randomized order: 1) a 6-h continuous infusion of [1,2-(13)C(2)]taurine (3.1 +/- 0.2 micromol x kg(-1) x h(-1)) and 2) a bolus injection of [(13)C(2)]taurine (3.0 +/- 0.1 micromol/kg). Isotope enrichments in plasma and whole blood taurine were determined by gas chromatography-mass spectrometry. The pilot experiments allowed us to establish that steady-state isotope enrichment was reached in plasma and whole blood by the 5th h of tracer infusion. The plateau enrichment reached in whole blood was lower than that obtained in plasma taurine (P < 0.02). In the second set of studies, the appearance rate (R(a)) of plasma taurine, determined from continuous infusion studies was 31.8 +/- 3.1 micromol x kg(-1) x h(-1). After a bolus injection of tracer, the enrichment decay over the subsequent 2 h was best fitted by a two-exponential curve. Taurine R(a) was approximately 85% higher when determined using the bolus injection technique compared with continuous infusion of tracer. We conclude that 1) taurine R(a) into plasma is very low in healthy postabsorptive humans, and, due to taurine compartmentation between the extra- and intracellular milieus, may represent only interorgan taurine transfer and merely a small fraction of whole body taurine turnover; and 2) the bolus injection technique may overestimate taurine appearance into plasma. Further studies are warranted to determine whether alterations in bile taurine dynamics affect taurine R(a).