Effects of halothane on arrhythmias induced by myocardial ischaemia

The effect of halothane on arrhythmias induced by ischaemia was investigated in rats, isolated perfused rat hearts, and pigs. Responses to the occlusion of the left anterior descending coronary artery were determined in groups (n = 9) of chronically prepared rats treated with no halothane, 0.5, or 1.0 per cent halothane immediately after occlusion; in isolated rat hearts (n = 10) treated with no halothane, 0.5, 1.0, 2.0, or 4.0 per cent halothane for 15 min before and after occlusion; and 20–25 kg pigs (n = 11) anaesthetised with halothane or pentobarbital. The ECG, arrhythmias, blood pressure (BP), heart rate (HR) and extent of infarction were determined in each model. In pigs, left ventricular pressure, dp/dt_max and cardiac output were also measured. In chronically prepared rats, halothane anaesthesia started after occlusion was antiarrhythmic and decreased the incidence of ventricular fibrillation and resulting mortality. In isolated rat hearts, 0.5 or 1.0 per cent halothane had little effect on occlusion-induced arrhythmias. The highest concentration of halothane increased the incidence of ventricular fibrillation both before and after occlusion. Halothane decreased developed ventricular pressure in a dose-dependent manner. In acutely prepared pigs, halothane pre-treatment had no appreciable effect upon occlusion-induced arrhythmias when compared with pentobarbital anaesthesia. Thus, halothane is antiarrhythmic when treatment is initiated after occlusion in the rat but this action is not seen in isolated hearts or intact pigs. The antiarrhythmic action of halothane is, therefore, species and model dependent.     

Anaesthetic experience with paediatric interventional cardiology

Anaesthetic and sedation techniques, complications and outcomes were reviewed in 176 children undergoing 184 interventional cardiologic procedures. Techniques included sedation only, and ketamine, inhalational or narcotic anaesthesia. Ketamine infusion was the technique most frequently used. Ketamine was associated with a higher incidence of respiratory complications (P < 0.05) than the other techniques. The higher incidence of hypercarbia (15.6 per cent), which did not affect outcome, may be attributable to the use of supplemental sedatives. The incidence of upper airway obstruction (7.8 per cent) was similar to that of previous studies. Vascular compromise resulted from the procedure in 33 patients, necessitating surgical correction in 16. Cardiac perforation occurred in four cases, causing one death. Pulmonary valve stenosis was most amenable to balloon dilatation and aortic valve stenosis least amenable. Ketamine was the anaesthetic agent preferred by cardiologists for use in the catheterisation suite when general anaesthesia was required. Vigilant monitoring by anaesthetic staff is necessary during the procedure, and avoidance of concomitant narcotics is recommended if a ketamine technique with spontaneous ventilation is used. Les techniques anesthésiques et de sédation ainsi que les complications et les issues ont été revues chez 176 enfants subissant 184 procedures cardiaques. Les techniques ont inctu soil la sédation seulement, soit l’anesthésie à la kétamine, aux agents d’inhalation ou aux narcotiques. La perfusion de kétamine était la technique la plus fréquemment utilisée. La ketamine était associée à une plus grande incidence de complication respiratoire (P < 0.05) comparativement aux autres techniques. La plus grande incidence d’hypercarbie (15.6 pour cent), n’ayant pas affecté l’issue, pourrait être attribuée à l’utilisation additionnelle de sédatifs. L’incidence d’obstruction des voies aériennes supérieures (7.8 pour cent) était similaire aux études préalables. Un problème vasculaire suite à la procédure fut observé chez 33 patients dont 16 ont requis une correction chirurgicale. Une perforation cardiaque est survenue dans quatre cas provoquant le décès d’un seul patient. La sténose de la valve pulmonaire était la procédure la plus susceptible d’être dilatée et la sténose de la valve aortique la moins susceptible. La kétamine était l’agent anesthésique préféré par les cardiologistes lors des cathétérisations quand une anesthésie générate était requise. Une surveillance vigilante par une équipe anesthésique fut nécessaire durant la procedure. Il faut aussi éviter l’administration de narcotiques si la kétamine est administrée en respiration spontanée.

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Presented in part at the Canadian Anaesthetists’ Society annual meeting in Halifax, June 1988.     

Hepatic,intestinal and renal transport of 1-naphthol-β-d-glucuronide in mutant rats with hereditary-conjugated hyperbilirubinemia

Summary Recently, a mutant rat strain was described with a genetic defect for the biliary excretion of organic anions (TR^– rats). To determine the possible heterogeneity of the transport systems in liver, intestine and kidney we investigated the transport of the anion 1-naphthol--d-glucuronide (1-NG) in isolated vascularly perfused organ preparations of the rat liver, intestine and kidney of both Wistar rats and TR^– rats. 1-NG was administered as such (liver and kidney experiments) or formed intracellularly from 1-naphthol (1-N) (liver and gut experiments). Independent of the type of exposure to 1-NG, the biliary excretion was considerably impaired in TR^– rats. In the intestine the total appearance and the vascular/luminal distribution pattern of 1-NG were not significantly different from the values in control rats. Furthermore, no significant disturbance was found with respect to the renal clearance of 1-NG in the TR^– rat when compared with the Wistar rat. Thus, the genetic defect in the TR^– rat is restricted to an impaired hepatobiliary excretion of 1-NG and does not affect the excretory systems of the intestine and kidney. These results suggest that the excretion of 1-NG by the liver, intestine and kidney involves distinct organ-specific transport systems.     

Inhibition of N-methyl-d-aspartate (NMDA) and l-glutamate-induced noradrenaline and acetylcholine release in the rat brain by ethanol

Summary The influence of ethanol on stimulation-evoked ³H-transmitter release was examined in slices of the rat brain cortex and corpus striatum preincubated with ³H-noradrenaline and ³H-choline, respectively. ³H-Transmitter release was stimulated by NMDA, l-glutamate, electrical impulses, reintroduction of Ca²⁺ ions (Ca²⁺-evoked release; after superfusion with Ca²⁺-free, K⁺-rich solution) or veratridine. In cortical slices preincubated with ³H-noradrenaline and superfused with Mg²⁺-free, otherwise physiologically composed salt solution, ethanol inhibited the NMDA- or l-glutamate-induced tritium overflow (IC₅₀ 45 and 37 mmol/l, respectively). In contrast, the tritium overflow in response to electrical stimulation, reintroduction of Ca²⁺ ions or veratridine was not affected by ethanol at concentrations up to 320 mmol/l; these experiments were carried out in cortical slices superfused with solution containing a physiological Mg²⁺ concentration. Ethanol also failed to inhibit Ca²⁺-evoked release in the absence of Mg2⁺ ions. In the presence of 1 mol/l veratridine, but not in its absence, NMDA induced tritium overflow even when cortical slices were superfused with salt solution containing a physiological Mg²⁺ concentration; again, ethanol inhibited this NMDA-evoked tritium overflow (IC₅₀ 73 mmol/l). In striatal slices preincubated with ³H-choline and superfused with Mg²⁺-free physiological salt solution, the NMDA-evoked tritium overflow was also, although at lower potency, inhibited by ethanol (IC₅₀ 192 mmol/l).In spite of the differences between the IC₅₀ values of ethanol determined for the inhibition of cortical noradrenaline and striatal acetylcholine release, it may be concluded that the NMDA receptor-ion channel complex is one of the sites of action underlying the ethanol-induced inhibition of neurotransmitter release. Since in the brain cortex the NMDA-induced ³H-noradrenaline release appears to be mediated by an excitatory interneurone activated by NMDA, this neuronal system may be involved in the cortical actions of ethanol.     

Nitric oxide synthesis in endothelial cytosol: Evidence for a calcium-dependent and a calcium-independent mechanism

Summary Release of nitric oxide (NO) from endothelial cells critically depends on a sustained increase in intracellular free calcium maintained by a transmembrane calcium influx into the cells. Therefore, we studied whether the free cytosolic calcium concentration directly affects the activity of the NO-forming enzyme(s) present in the cytosol from freshly harvested porcine aortic endothelial cells. NO was quantified by activation of a purified soluble guanylate cyclase coincubated with the cytosol. In the presence of 1 mM L-arginine, 0.1 mM NADPH and 0.1 mM EGTA, endothelial cytosol (0.2 mg of cytosolic protein per ml) stimulated the activity of guanylate cyclase 5.0 + 0.5-fold (from 31 + 9 to 153 + 15 nmol cyclic GMP formed per min per mg guanylate cyclase). Calcium chloride increased this stimulation further in a concentration-dependent fashion by up to 136 + 15% (with 2 M free calcium; EC₅₀ 0.3 M). The calcium-dependent and -independent activation of guanylate cyclase was enhanced by superoxide dismutase (0.3 M) and was inhibited by the stereospecifically acting inhibitor of L-arginine-dependent NO formation N^G-nitro-L-arginine (1 mM) and by LY 83583 (1 M), a generator of superoxide anions. Our findings suggest a calcium-dependent and -independent synthesis of NO from L-arginine by native porcine aortic endothelial cells. Send of fprint requests to A. Mülsch, at the above address     

Effects of the NMDA antagonists CPP and MK-801 on delayed conditional discrimination

N-methyl-D-aspartate (NMDA) receptor/channel antagonists have previously been shown to impair spatial working memory and hippocampal long-term potentiation. The present experiment investigated the effects of a variety of doses of NMDA antagonists on a working memory task in rats involving an auditory delayed conditional discrimination. Signal detection analysis and an exponential memory decay model were used to extract independent measures of stimulus discriminability and rate of forgetting. A competitive NMDA antagonist, (CPP, 0.33, 1.0, 10.0 mg/kg, IP) produced a reduction in discriminability which was linearly related to log dose, but which was only clear at the 10 mg/kg dose. Rate of forgetting was not increased by any dose. Similar results were obtained with a non-competitive antagonist (MK-801, 0.1, 0.33 mg/kg, IP). These data suggest that doses of NMDA receptor channel antagonists sufficient to disrupt hippocampal long-term potentiation and radial arm maze performance will also disrupt delayed conditional discrimination. The effect on delayed conditional discrimination is due to a disruption of stimulus discriminability and not to an increased rate of forgetting. The extent to which these effects relate to the reported changes in hippocampal long-term potentiation and radial arm maze performance remains to be determined.     

Anger Management Style and Hostility: Predicting Symptom-Specific Physiological Reactivity Among Chronic Low Back Pain Patients

It was hypothesized that anger management style (anger-in or anger-out) and hostility affect the aggravation of chronic low back pain (CLBP) through symptom-specific (i.e., lower paraspinal muscle) reactivity during stress. Subjects were 102 CLBP patients who performed mental arithmetic and an Anger Recall Interview (ARI) while trapezius and lower paraspinal EMG, SBP, DBP, and HR were recorded. Results showed anger-in × hostility and anger-out × gender interactions for lower paraspinal but not trapezius reactivity, and only during the ARI. Further analyses revealed that (1) hostility was related positively to lower paraspinal reactivity among high anger suppressors, (2) hostility was related negatively to lower paraspinal reactivity among low anger suppressors, and (3) anger expression was related positively to lower paraspinal reactivity only among men. Anger management style and hostility may contribute to the exacerbation of CLBP by influencing stress reactivity only in muscles near the site of pain or injury.     

深圳市警察心理素质研究Ⅲ.心理健康与应对方式调查

目的：探讨深圳警察的心理健康和应对方式及其与人口学特征的关系。方法：通过团体测试方式对6107名深圳警察进行症状自评量表(SCL-90)和简易应对方式问卷调查。结果：深圳警察SCL-90的总均分、阳性症状均分及l0个因子分均显著低于全国常模；其积极应对得分显著高于全国常模，而消极应对得分显著低于全国常模。深圳男性警察的躯体化、强迫、人际敏感、敌对、偏执、精神病及总均分均显著高于女性，其积极应对得分显著低于女性。36-40岁年龄段及副科级警察SCL-90多项因子分在各年龄段及各职务级别警察中得分最高；45岁以前，随着年龄的递增，积极应对和消极应对两维度的均分均相应递增。结论：年龄、性别、文化程度和职务级别的不同对深圳警察的心理健康状况和应对方式存在一定影响。积极应对有利于心理健康。     

Mechanism of the enhancing effect of sorbitol on ileal Ca uptake in rat enterocytes

The effect of sorbitol on Ca uptake by isolated ileal epithelial cells was investigated. Intestinal cells were isolated from rat ileum by mechanical vibration.⁴⁵Ca uptake was approximately 2 times higher in cells exposed to 200 mM sorbitol ofd-alanine than in control cells. This enhancing effect of sorbitol on percentage Ca uptake decreased with increasing Ca concentrations in the incubation medium suggesting an effect on Ca entry velocity. The addition of 10 M nifedipine or 200 M verapamil to the incubation medium was devoid of any effect on Ca uptake in ileal cells, whereas 100 M trifluoperazine or chlorpromazine abolished the stimulatory effect of sorbitol. Finally, the effect of sorbitol on isolated cells was independent of a measurable change of cellular ATP content. In conclusion, the stimulatory effect of sorbitol on ileal Ca uptake is probably exerted through mechanisms other than an increase in intracellular ATP concentration. Sorbitol may enhance enterocyte Ca transport via a direct interaction with calmodulin and/or the Ca pump. It may also exert its effect through an inhibition of the basolateral Na Ca exchanger.     

军校部队生与地方生人格、应对方式及心理健康研究

目的 了解军校部队生与地方生的心理健康、人格和应对方式等情况,为加强大学生心理健康教育提供依据.方法 采用症状自评量表、艾森克个性问卷、简易应对方式问卷,对临床本科的部队生与地方生进行测评分析.结果 部队生心理健康状况总体上好于地方生,躯体化、人际敏感、抑郁、焦虑等轻于地方生,性格相对外向,且处事相对稳重,应对方式以积极成熟的为主,统计学检验P＜0.05或P＜0.01.结论 军人的责任感与自豪感有助于部队生的心理健康,而对军事化管理出现思想上的错误认识是地方生心理问题产生的主要原因.