[The false positive reaction of the Triage panel drug-of-abuse by herbal drugs ma-huang (Ephedra sinica (Ephedraceae))].

We investigated false-positive reactions obtained from a drug screening test using a Triage panel. We detected 2 cases giving false-positive reaction for AMP (amphetamine, methamphetamine) during the screening of 187 normal subjects. Subsequent follow up testing by high-performance liquid chromatography (HPLC), showed both to be false-positive reactions. As both cases have a history of ingesting the herbal drug, Ma-huang (Ephedra sinica (Ephedraceae)), containing ephedrine, we examined the relationship between false-positive reactions on Triage and Ma-huang. All urine samples collected from 7 healthy volunteers following administration of Ma-huang indicated AMP positive on Triage. Also a high ratio of AMP positives was observed in the patients who were administered Ma-huang-containing drugs at the hospital. However, none of them were identified as true-positives by HPLC or gas chromatography mass spectrometry (GC/MS) analysis. The extract of Ma-huang contained in herbal drugs, which otherwise contain neither amphetamine nor its derivatives, gives (AMP) positive indications on Triage. We speculate that unidentified components of Ma-huang cause the false-positive reactions. We suggest that follow-up tests by GC/MS or HPLC are needed wherever a positive result is obtained from a screening test by Triage. Furthermore, it will be established to continue collecting information on prescribed and non-prescribed drugs.

[Simultaneous administration of ethanol emphasizes the effect of methamphetamine on central nervous system in rat with high alcohol preference].

We studied about influence of alcohol preference and of simultaneously administered ethanol (EtOH) on the effect of methamphetamine (MA) on the central nervous system neurochemically and behavioral pharmacologically using two strains of rat with high or low preference for alcohol (HAP and LAP). In the neurochemical study, we determined dopamine (DA) and serotonin (5-HT) level in striatum and nucleus accumbens (N.Acc) by means of brain microdialysis after administration of MA 1 mg/kg alone (LAP-MA group, HAP-MA group) or EtOH 2 g/kg + MA 1 mg/kg (LAP-EtOH/MA group, HAP-EtOH/MA group) every 20 minutes for 10 sessions. In the behavioral pharmacological study, we observed rat's behavior in the open field and performed scoring according to Locomotion-Stereotypy (L-S) rating scale by Ellinwood every five minutes, and counted locomotion and rearing by means of infrared beam cutting every 20 minutes after administration of MA 1 mg/kg alone (LAP-MA group, HAP-MA group) or EtOH 2 g/kg + MA 1 mg/kg (LAP-EtOH/MA group, HAP-EtOH/MA group). When MA was given alone, HAP rat showed no significant difference in locomotion, rearing and L-S score compared to LAP rat, although HAP rat showed significantly lower elevation of DA and 5-HT in both striatum and N.Acc. When EtOH was simultaneously administered with MA, in LAP rat, DA and 5-HT elevation in the striatum and N.Acc showed no significant differences between LAP-EtOH/MA group and LAP-MA group. Locomotion and rearing reduced and L-S score temporarily reduced significantly in LAP-EtOH/MA group compared to LAP-MA group. However in HAP rat, HAP-EtOH/MA group showed significantly higher DA and 5-HT elevation in both striatum and N.Acc, and also showed significantly higher L-S score and higher locomotion count compared to HAP-MA group. Our results indicate that effect of MA may be influenced by alcohol preference, and that simultaneous administration of EtOH emphasizes the effect of MA on central nervous system in rat with high alcohol preference.

Impairment of antigen-specific antibody production in transgenic mice expressing a dominant-negative form of gp130.

gp130 is a common signal-transducing receptor component for the interleukin 6 family of cytokines functioning in, for example, immune, hematopoietic, and nervous systems. In this study, to investigate the physiological functions of gp130 and to determine the pathological consequences of impaired gp130 signals, we have generated transgenic mice expressing a cytoplasmically truncated form of mouse gp130. Expression of this form of gp130 in lymphocytes significantly suppressed interleukin 6-induced tyrosine phosphorylation of endogenous gp130 and a downstream signaling molecule, signal transducer and activator of transcription 3, indicating that this form has a dominant negative function. In spite of the impaired gp130 signals, the development of lymphocytes in the transgenic mice appeared normal in terms of surface marker phenotypes. These mice, however, exhibited severe defects in antigen-specific antibody production of most immunoglobulin isotypes other than IgM after immunization with 2,4-dinitrophenol-conjugated ovalbumin. These results demonstrate in vivo that gp130 is essential for antigen-specific antibody production.

Vasorelaxant effects of oxpentifylline and theophylline on rat isolated aorta.

The mechanism of the relaxation response of rat aorta to the phosphodiesterase inhibitors oxpentifylline and theophylline was studied. Oxpentifylline induced a greater vasorelaxation response in the intact strips than in those without endothelium. The endothelium-dependent relaxation response to oxpentifylline was inhibited by nitro-L-arginine but not by indomethacin, and the endothelium-independent relaxation response was potentiated by the combination with isoprenaline but not sodium nitroprusside. Theophylline induced a similar relaxation response in vascular strips with and without endothelium. The relaxation response to theophylline was not inhibited by indomethacin or nitro-L-arginine in intact strips, but was potentiated by combination with isoprenaline or sodium nitroprusside in the denuded strips. These results suggest that the two phosphodiesterase inhibitors oxpentifylline and theophylline induce vasorelaxation by different mechanisms. Oxpentifylline can induce both endothelium-dependent relaxation, which is probably mediated by an endothelium-derived relaxing factor, and endothelium-independent relaxation, which may be due to an inhibitory action on phosphodiesterase of vascular smooth muscle. In contrast, theophylline can induce endothelium-independent relaxation alone, without modulation by the endothelium.

[Effect of nafamostat mesilate on the renin-aldosterone system].

It has been reported that continuous intravenous infusion of nafamostat mesilate (FUT) produces hyperkalemia due to reduced urinary excretion of potassium. The present study was performed to see whether renin-aldosterone effect is involved in this inhibition of potassium excretion. Ten patients were studied who had been given this drug (4 mg.hr-1) to prevent postsurgical pancreatitis or DIC. Urine potassium output decreased significantly from 44 +/- 5 microEq.min-1 prior to administration of FUT to 18 +/- 4 microEq.min-1 in 3 hours, sodium/potassium ratio increased significantly from 1.7 +/- 0.7 prior to administration of FUT to 5.4 +/- 3.3 in 5 hours; and plasma aldosterone decreased significantly from 92 +/- 24 pg.ml-1 prior to administration of FUT to 63 +/- 22 pg.ml-1 in 6 hours. The results suggest that hyposecretion of aldosterone may be one of the main causes of hypokalemia. Reduced secretion of aldosterone may be due to other factors than the suppression of renin-angiotensin system.

[The present status and problems of repatriation in France].

In France, repatriation, the inter-continental or interhospital critical care transport, is done on a large scale mainly by private companies with sophisticated medical knowledge, techniques and equipment. They offer a great assistance to SAMU when a disaster occurs. It is notable that almost all doctors who work for these companies are anesthesiologists and trained in SAMU. Repatriation is a large field involving critical care transport which includes intensive care medicine and disaster medicine as well as emergency medicine. One of the most important things about repatriation is that the judgement should be done and means of transport of the patient should be decided based purely on medical grounds.

[The anesthesiologist's role in the French emergency medical system].

The present system of French emergency medicine and its philosophy were described from my experience at SAMU (service d'aide medicale urgente). Three factors of emergency medicine; pre-hospital care, emergency transport and emergency information service are managed by anesthesiologists. Anesthesiologists on duty at the tele-medicine center give medical team instructions to start at once. The team is composed of an anesthesiologist, a nurse and an ambulancier. They start to give intensive care medicine to critically ill patients on the spot. The philosophy of SAMU is that doctors should go out of the hospital. Anesthesiologists in the area organize the emergency medical system in France.