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Objective The use of an intravenous catheter with a rest period has been recommended to avoid false-positive results for hyperprolactinaemia and false-negative results for hypocortisolaemia. We tested the relevance of this recommendation. Design Plasma cortisol and prolactin levels were determined before (T-15) and after a 15-min rest period (T0) in 119 patients, 38 males (M) and 81 females (F). 52 of the 119 patients were known (K; 30 females and 22 males) and 67 unknown (UK; 49 females and 18 males) to the unit. Results Prolactin was lower after rest in women (12.3 ± 22.7 ng/l vs 11.7 ± 22.5 ng/ml, P = 0.03), but not in men (6.2 ± 4.5 ng/ml at T-15 vs 5.8 ± 3.2 ng/ml at T0, P = 0.09), in the UK subgroup (10.6 ± 20.7 ng/ml at T-15 vs 10.1 ± 20.9 ng/ml at T0, P = 0.06) and in the K subgroup (10.1 ± 16.7 ng/ml at T-15 vs 9.7 ± 15.8 ng/ml at T0, P = 0.08). None of the patients with prolactin levels higher than 20 ng/ml at T-15 diminished its prolactin value below this cut-off value. Plasma cortisol levels were lower after rest in women (17.9 ± 5.9 μg/dl at T-15 vs 16.5 ± 6.1 μg/dl at T0, P P = 0.0003) but not in men (18 ± 4.4 μg/dl at T-15 vs 17.5 ± 5.8 μg/dl at T0, P = 0.47) and in the K subgroup (17.8 ± 4.6 μg/dl at T-15 vs 17 ± 5.4 μg/dl at T0, P = 0.13). At T0, 3.3% and 15% of patients presented values below the cut-off value of 10 μg/dl (276 nmol/l) and 17 μg/dl (470 nmol/l), respectively. Conclusion These results don’t justify intravenous catheterisation with a rest period for plasma prolactin determination in contrast with plasma cortisol determination.

Les tumeurs fibreuses solitaires sont des tumeurs d’origine mesenchymateuse, de croissance lente. Malignes dans moins de 20 % des cas, elles peuvent se compliquer de syndromes paraneoplasiques. Nous rapportons le cas d’un patient âge de 72 ans, atteint d’une tumeur fibreuse solitaire, evolutive. De localisation thoracique, la tumeur n’avait pu beneficier d’une resection complete, et le patient beneficiait d’une troisieme ligne de chimiotherapie. Il a ete hospitalise dans un contexte de comas hypoglycemiques a repetition. Le bilan au decours d’une hypoglycemie a pu mettre en evidence : – un cortisol freine, temoignant d’une infiltration metastatique surrenalienne ; – une insulinemie, une pro-insuline et un C-peptide effondres, eliminant une hypersecretion d’insuline ; – un βhydroxybutyrate bas, evoquant une mediation par le recepteur de l’insuline ; – un axe somatotrope freine avec GH a 0.6 mUI/L, IGF1 a 49.4 ng/mL (N 26–221) et IGF2 a 561 ng/mL (N 459–1123), evoquant une hypoglycemie induite par la secretion d’IGF2, ou big-IGF2. L’Insulin Growth Factor secrete par la masse tumorale stimule le recepteur de l’insuline avec une action hypoglycemiante supra-physiologique, et freine la secretion de GH. La corticotherapie a ete inefficace, l’association a un traitement par GH a fortes doses a permis un arret des hypoglycemies. Celui-ci a pu etre interrompu apres une nouvelle resection chirurgicale de la tumeur. La tumeur fibreuse solitaire est une cause rare mais connue d’hypoglycemie organique. Il s’agit d’un syndrome paraneoplasique avec secretion d’IGF2. Les hypoglycemies repondent au traitement par GH, la chirurgie de reduction de volume tumoral est le traitement de choix.

Objective Ultra-endurance events may induce biological changes as a consequence of intense muscle stress and hormonal fluctuations. Two ultra-endurance athletes, one on treadmill, the other on a home trainer pinion, have attempted to break world records for greatest distance covered over 6 days in Paris on January 4–10, 2015 (“six extreme days”). We analyzed the hematological, hormonal and biochemical changes. Materials and methods Hematological, biochemical, hormonologic, metabolic and specific to oxidative stress analysis were conducted on fresh and frozen blood samples collected a week before (D-7), 30 minutes (D6) and 2 days (D8) after the event for both sportsmen. Periods of waking/sleep, cardiovascular data (pulse, saturation) and developed efforts (distance, speed) were monitored throughout the event. Results Hemoglobin, hematocrit and iron parameters (serum iron, ferritin, transferrin saturation coefficient) were found lower on D6, after 2750 km cycling or 713 km running, than on D-7 (hemoglobin decreased from 15.2 g/dl before the event to 13.3 g/dl just after). They start to increase back on D-8. Leukocytes (6.5 to 9.4 G/l between D-7 and D-6), haptoglobin (tripled between D-7 and D-8, from 1 to 3 g/l), liver enzymes, Creatine Phosphokinase, troponin, Brain Natriuretic Peptide and uric acid rose during the event before going back down on D8 without however reaching back initial levels. Discussion The observed transient anemia is multifactorial, inflammatory, iron deficiency but without here any element for hemolysis. Hepatic cytolysis and heart stress are commonly encountered [1] . No study however focuses on oxidative stress enzymes (glutathione, lipid peroxidation products, activation of xanthine oxidase) after such a long effort, for which mobilization of leukocytes and increased uric acid (antioxidant) are indirect markers [2] . Data from this exploration should help enhancing our understanding of the impact of very prolonged effort on the oxidative stress chain, and paves the way for potential improvement in the training methods of athletes.

Beta 2-microglobulin (beta 2M) is responsible for dialysis-associated amyloidosis. Level of beta 2M in plasma increase during chronic renal failure; however, retention does not appear to be the sole mechanism responsible. The effect of metabolic acidosis on beta 2M production was examined. Thirty-six patients with stable chronic renal insufficiency, 12 uremic patients before their first dialysis, 8 hemodialysis patients who were assigned to acetate or bicarbonate dialysate and then crossed over to the alternative regimen, and 6 normal subjects given NH4Cl to initiate metabolic acidosis were studied. In vitro studies in the human myeloid cell line U 937 were also performed. beta 2M protein was measured with ELISA, beta 2M mRNA was measured with reverse transcription polymerase chain reaction, and the U 937 cells were studied at two pH levels with FACScan flow cytometry. The cells were exposed in vitro up to 60 min in a buffered incubation medium to either pH 5.10 or pH 7.34. An inverse correlation was found between beta 2M and bicarbonate concentrations in plasma in the stable chronic renal failure patients (r = -0.54; P0.05) and in the uremic patients before their first dialysis (r = -0.72; P0.05). In hemodialysis patients, blood pH and plasma bicarbonate values were lower (P0.05) and beta 2M concentrations in plasma were higher (P0.05) with acetate than with bicarbonate dialysate. In normal men, NH4Cl resulted in an increase (P0.05) in beta 2M mRNA expression in lymphocytes by an average factor of 1.5 (range, 1.1 to 1.8). In U 937 cells, the cell surface expression of beta 2M and HLA Class I heavy chain assembled with beta 2M decreased at low pH compared with normal pH. Concomitantly, an increase in beta 2M release into the supernatant was observed, possibly as the result of beta 2M dissociation from cell surface HLA Class I complex. The results suggest that metabolic acidosis may enhance cellular beta 2M generation and release.

The use of an intravenous catheter with a rest period has been recommended to avoid false-positive results for hyperprolactinaemia and false-negative results for hypocortisolaemia. We tested the relevance of this recommendation.Plasma cortisol and prolactin levels were determined before (T-15) and after a 15-min rest period (T0) in 119 patients, 38 males (M) and 81 females (F). 52 of the 119 patients were known (K; 30 females and 22 males) and 67 unknown (UK; 49 females and 18 males) to the unit.Prolactin was lower after rest in women (12.3+/-22.7 ng/l vs 11.7+/-22.5 ng/ml, P=0.03), but not in men (6.2+/-4.5 ng/ml at T-15 vs 5.8+/-3.2 ng/ml at T0, P=0.09), in the UK subgroup (10.6+/-20.7 ng/ml at T-15 vs 10.1+/-20.9 ng/ml at T0, P=0.06) and in the K subgroup (10.1+/-16.7 ng/ml at T-15 vs 9.7+/-15.8 ng/ml at T0, P=0.08). None of the patients with prolactin levels higher than 20 ng/ml at T-15 diminished its prolactin value below this cut-off value. Plasma cortisol levels were lower after rest in women (17.9+/-5.9 microg/dl at T-15 vs 16.5+/-6.1 microg/dl at T0, P0.0001), in the UK subgroup (18+/-6.1 microg/dl at T-15 vs 16.6+/-6.4 microg/dl at T0, P=0.0003) but not in men (18+/-4.4 microg/dl at T-15 vs 17.5+/-5.8 microg/dl at T0, P=0.47) and in the K subgroup (17.8+/-4.6 microg/dl at T-15 vs 17+/-5.4 microg/dl at T0, P=0.13). At T0, 3.3% and 15% of patients presented values below the cut-off value of 10 microg/dl (276 nmol/l) and 17 microg/dl (470 nmol/l), respectively.These results don't justify intravenous catheterisation with a rest period for plasma prolactin determination in contrast with plasma cortisol determination.