Skin vascular resistance in the standing position increases significantly after 7 days of dry immersion.

Actual and simulated microgravity induces hypovolemia and cardiovascular deconditioning, associated with vascular dysfunction. We hypothesized that vasoconstriction of skin microcirculatory bed should be altered following 7 days of simulated microgravity in order to maintain cardiovascular homeostasis during active standing. Eight healthy men were studied before and after 7 days of simulated microgravity modeled by dry immersion (DI). Changes of plasma volume and orthostatic tolerance were evaluated. Calf skin blood flow (laser-Doppler flowmetry), ECG and blood pressure signal during a 10-min stand test were recorded, and skin vascular resistance, central hemodynamics, baroreflex sensitivity and heart rate variability were estimated. After DI we observed increased calf skin vascular resistance in the standing position (12.0 ± 1.0 AU-after- vs. 6.8 ± 1.4 AU-before), while supine it was unchanged. Cardiovascular deconditioning was confirmed by greater tachycardia on standing and by hypovolemia (-16 ± 3% at day 7 of DI). Total peripheral resistance and indices of cardiovascular autonomic control were not modified. In conclusion, unchanged autonomic control and total peripheral resistance suggest that increased skin vasoconstriction to standing involves rather local mechanisms-as venoarteriolar reflex-and might compensate insufficient vasoconstriction of other vascular beds.

Suicide by skull stab wounds: a case of drug-induced psychosis.

Suicide by stabbing to the head and/or driving sharp objects into the skull is of extreme rarity. This article reports the case of a 27-year-old man, who committed suicide by multiple knife stabs and cuts to the head, the torso, one shoulder and the forearms. Autopsy showed a perforating wound of the skull and the 10-cm long broken blade of the knife being still embedded in the right temporal lobe of the brain. The deceased had no history of psychiatric illness but was currently treated by mefloquine, a quinine derivative associated with a high rate of psychiatric adverse effects. Toxicological examination confirmed a recent intake of mefloquine together with chloroquine, another antimalarial drug. To our knowledge, this is the first report of a completed suicide with very strong evidence of mefloquine implication. Discussion focuses upon mefloquine-induced psychiatric disorders and highlights the importance of performing toxicological investigations in cases of unusual suicides.

High-performance liquid chromatography coupled with electrospray tandem mass spectrometry (LC/MS/MS) method for the simultaneous determination of diazepam, atropine and pralidoxime in human plasma.

A high-performance liquid chromatography coupled with electrospray tandem mass spectrometry (LC/MS/MS) procedure for the simultaneous determination of diazepam from avizafone, atropine and pralidoxime in human plasma is described. Sample pretreatment consisted of protein precipitation from 100microl of plasma using acetonitrile containing the internal standard (diazepam D5). Chromatographic separation was performed on a X-Terra MS C8 column (100mmx2.1mm, i.d. 3.5microm), with a quick stepwise gradient using a formate buffer (pH 3, 2mM) and acetonitrile at a flow rate of 0.2ml/min. The triple quadrupole mass spectrometer was operated in positive ion mode and multiple reaction monitoring was used for drug quantification. The method was validated over the concentration ranges of 1-500ng/ml for diazepam, 0.25-50ng/ml for atropine and 5-1000ng/ml for pralidoxime. The coefficients of variation were always <15% for both intra-day and inter-day precision for each analyte. Mean accuracies were also within +/-15%. This method has been successfully applied to a pharmacokinetic study of the three compounds after intramuscular injection of an avizafone-atropine-pralidoxime combination, in healthy subjects.

Phase I study of weekly oxaliplatin in relapsed or refractory pediatric solid malignancies.

PURPOSE: To explore feasibility, maximum-tolerated dose (MTD), and recommended dose (RD) for phase II studies of weekly oxaliplatin for the treatment of relapsed or refractory pediatric solid malignancies. PATIENTS AND METHODS: Eligible patients were 6 months to 21 years old, had a diagnosis of a solid malignancy, and had experienced treatment failure with at least two or more previous lines of therapy. The phase I study was multicentric, open-label, and nonrandomized. It foresaw two phases: a dose-escalation phase (comprising six levels) to find the RD and an extension at the RD to evaluate the cumulative toxicity. Oxaliplatin was administered intravenously over 2 hours on days 1, 8, and 15 of a 28-day cycle. RESULTS: Forty-five patients were enrolled: 29 patients in the dose-escalation phase and 16 patients in the extension at the RD. Median age was 9.5 years (range, 2.8 to 20.0 years) and 7.8 years (range, 1.8 to 19.2 years), respectively. The dose-limiting toxicities during the first treatment cycle were grade 3 (G3) sepsis at 50 mg/m(2), G3 dysesthesia at 90 mg/m(2), and G3 dysesthesia and G3 paresthesia at 110 mg/m(2), thus the MTD and RD was 90 mg/m(2). No case of ototoxicity was reported. Stable disease was reported in seven patients (16.3%), and confirmed partial response was observed in two patients (4.7%), one with neuroblastoma and one with osteosarcoma. CONCLUSION: Oxaliplatin administered in a weekly schedule has an acceptable safety profile, different from cisplatin and carboplatin, and shows activity in children with relapsed or refractory solid tumors, suggesting further investigation in pediatric malignancies.

Gene expression profiling of human skeletal muscle in response to stabilized weight loss.

BACKGROUND: Diet-induced weight reduction promotes a decrease in resting energy expenditure that could partly explain the difficulty in maintaining reduced body mass. Whether this reduction remains after stabilized weight loss is still controversial, and the molecular mechanisms are unknown. OBJECTIVE: The objective was to investigate the effect of a stabilized 10% weight loss on body composition, metabolic profile, and skeletal muscle gene expression profiling. DESIGN: Obese women were assigned to a 4-wk very-low-calorie diet, a 3-6-wk low-calorie diet, and a 4-wk weight-maintenance program to achieve a 10% weight loss. Resting energy expenditure, body composition, plasma variables, and skeletal muscle transcriptome were compared before weight loss and during stabilized weight reduction. RESULTS: Energy restriction caused an 11% weight loss. Stabilization to the new weight was accompanied by an 11% decrease in the resting metabolic rate normalized to the body cellular mass. A large number of genes were regulated with a narrow range of regulation. The main regulated genes were slow/oxidative fiber markers, which were overexpressed, and the gene encoding the glucose metabolism inhibitor PDK4, which tended to be down-regulated. The knowledge-based approach gene set enrichment analysis showed that a set of genes related to long-term calorie restriction was up-regulated, whereas sets of genes related to insulin, interleukin 6, and ubiquitin-mediated proteolysis were down regulated. CONCLUSIONS: Weight loss-induced decreases in resting metabolic rate persist after weight stabilization. Changes in skeletal muscle gene expression indicate a shift toward oxidative metabolism.

[Spectacular suicide associated with mefloquine]. / Suicide spectaculaire lié à une prise de méfloquine.

INTRODUCTION: We present a case in which suicide was a severe neuropsychiatric reaction to treatment with mefloquine. Physicians must be aware of these serious psychiatric complications and bear them in mind when faced with atypical behavior or suspected suicide. CASE REPORT: The body of a 27-year-old man was discovered at his home, covered with multiple knife wounds. The autopsy report concluded that death was due to a craniocerebral wound from a violent blow. Homicide was initially suspected. Suicide during acute psychosis associated with mefloquine was suggested, and toxicologic analyses confirmed this hypothesis. DISCUSSION: Serious neurologic and psychiatric adverse events associated with mefloquine (Lariam) have been reported since its introduction in 1985. Mefloquine prophylaxis is recommended for travelers to high-risk areas of chloroquine-resistant plasmodium falciparum. The risk of malarial infection and the proven efficacy of mefloquine to prevent malaria should be weighed against the risk of drug-associated adverse events. Physicians must nonetheless be aware of these serious psychiatric complications, especially when faced with atypical behavior and atypical suicides. The patient's' family and friends should be asked about a possible trips abroad that might have entailed antimalaria treatment, even several months earlier. Testing for mefloquine during toxicological examinations is then essential. The World Health Organization recommendations and contraindications must be followed in prescribing mefloquine.

Defect in epinephrine production in children with craniopharyngioma: functional or organic origin?

Despite pituitary hormone replacement, patients with craniopharyngioma often complain of fatigue. They may have deficient control of catecholamine secretion caused by hypothalamic lesion. Another hypothesis is a functional defect in catecholamine production through either glucocorticoid deficiency because high intraadrenal glucocorticoid concentration is necessary for epinephrine synthesis or unrecognized hypoglycemia, which can intrinsically alter epinephrine secretion. We measured catecholamine response to insulin-induced hypoglycemia and orthostasis, and 24-h urinary catecholamine excretion, in 16 children with craniopharyngioma (patients) and 27 sex- and age-matched short children. We also studied the influence of a 4-fold increase in the usual daily dose of hydrocortisone on catecholamine excretion (50 vs. 12 mg/m(2) of body surface area) in the glucocorticoid-deficient patients. Last, we compared 24-h continuous sc glucose in patients and 10 sex- and age-matched healthy children. The results are expressed as medians (25th, 75th). For a similar blood glucose nadir after insulin administration, peak plasma epinephrine in response to hypoglycemia was lower in patients vs. controls [420 (120, 715) vs. 730 (460, 1200) ng/liter, P < 0.01], whereas peak plasma norepinephrine was higher [390 (280, 550) vs. 270 (180, 280) ng/liter, P < 0.05]. Catecholamine response to orthostasis did not differ between groups. Urinary epinephrine was significantly lower in patients (P < 0.001), whereas urinary norepinephrine was similar. The extent of epinephrine deficiency correlated with neither tumor size nor hypothalamic involvement. A 4-fold higher hydrocortisone dose did not correct the defective epinephrine excretion in the glucocorticoid-deficient patients. Last, the 24-h sc glucose values were similar between patients and controls. In conclusion, children with craniopharyngioma have a defect in epinephrine but not norepinephrine production. There is no proof of a univocal origin, either organic or functional. Whether abnormal catecholamine secretion alters glucose level during fasting or acute illness, or hampers adaptation to exercise, requires further studies.

Potential beneficial as well as detrimental effects of chronic treatment with lisinopril and (or) spironolactone on isolated hearts following low-flow ischemia in normal and infarcted rats.

This study was designed to demonstrate potential beneficial as well as detrimental effects of lisinopril and spironolactone given in combination. In patients with congestive heart failure or myocardial infarction, the use of angiotensin-converting enzyme (ACE) inhibitors may inhibit aldosterone production. Spironolactone, a specific aldosterone receptor antagonist may exert other independent and additive effects to those of ACE inhibitors. Given the consequences of aldosterone on ischemic hearts, we evaluated the protective effects of spironolactone or lisinopril and combined spironolactone-lisinopril therapy during low-flow ischemia and reperfusion in isolated rat hearts. Normal and infarcted (left coronary artery ligature) male Wistar rats were submitted to chronic action of drugs (0.8 mg.kg-1.day-1 for lisinopril and 8 or 50 mg.kg-1.day-1 for spironolactone) for 1 month. Hearts were rapidly excised and perfused (constant pressure) for a 40-min period of stabilization followed by a 25-min period of global low-flow ischemia and a 30-min reperfusion. In normal rats, spironolactone decreased ischemic and reperfusion contracture, reduced ventricular tachycardia, suppressed action-potential duration dispersion, and increased reactive hyperemia leading to an improvement of contractile recovery. Lisinopril also decreased ventricular tachycardia and action-potential duration dispersion concomitantly with increased reactive hyperemia and better contractile recovery. These beneficial effects of the drugs were lost when the two treatments were combined (lisinopril and 50 mg.kg-1.day-1 spironolactone), despite a synergistic effect on plasmatic K+ and Mg2+. However, an interaction between the ACE inhibitor and spironolactone potentiating the effects of either drug alone was observed with a lower dose of spironolactone (lisinopril and 8 mg.kg-1.day-1 spironolactone). Similar beneficial effects have been noted in infarcted rat hearts on reactive hyperemia, ventricular tachycardia, and contractile recovery with the combined treatment and for both spironolactone concentrations (8 or 50 mg). Chronic spironolactone treatment produces similar beneficial effects to ACE inhibitor treatment on normal rat hearts during an ischemia-reperfusion protocol. Synergistic effects have been observed with the combined therapy when a lower dose of spironolactone was utilized in normal and infarcted rats. However, in the case of a high dose of spironolactone, the two effective drugs seem to cancel each other but only in normal rats.