低分子量聚合物电解质的合成与性能

研究了低分子量梳状聚合物电解质的合成方法及结构，性能。首先合成了不同分子量的甲基丙烯酸聚乙二醇单甲醚酯，并进一步合成了分子量一万左右的梳状聚合物电解质，结果表明：反应严格按照反应方程进行，精制产物是非晶的梳状聚合物，本聚合物体系均存在两个玻璃化转变温度，一个在100℃左右，归属为梳状聚合物主链的玻璃化转变，另一个在－20摄氏度以下，归属于侧链玻璃化转变，在室温下侧链可以运动，有利于电活性物质的迁移和扩散，并用超微电极研究了该电解质的行为。     

捻转补泻手法针刺合谷穴对其局部皮肤温度的影响

目的阐明针刺捻转补法与泻法的操作是否存在效应上的差异,并探讨其效应差异是否为补泻效应的差异.方法应用红外线热像技术,采用不同的捻转补泻手法针刺健康人合谷穴后,观察其在即刻,10、20、30min,对局部皮肤温度的影响.结果不同捻转补法与泻法的操作存在着不同程度的效应差异,其中补法可以使皮温升高,泻法可以使皮温降低,以石氏捻转补泻针法较为明显.结论1)补泻手法,补法和泻法的操作可产生不同的效应.2)不同捻转补泻手法对皮肤温度产生的升降效应为补泻效应,其中以石氏捻转补泻手法最为明显.3)证明补泻手法实施的必要性.     

Non-invasive temperature imaging of muscles with magnetic resonance imaging using spin-echo sequences

The application of spin-echo magnetic resonance imaging sequences on non-invasive temperature imaging for temperature mapping of human limbs is investigated. In an in vitro expriment performed on a meat sample, the equilibrium magnetisation P and the spin-lattice relaxation time T₁ are calculated from the values for the repetition time TR and the signal intensities obtained by a spin-echo sequence at different tissue temperatures tures as measured by a fibre-optic probe. T₁ is linearly correlated to the tissue temperature, and P is linearly correlated to the reciprocal value of the absolute temperature. Both effects, taken together, lead to a non-linear dependency of the signal intensity on temperature. Therefore a TR leading to maximum temperature dependency of the signal intensity is calculated and used in the futher experiments. In the in vivo experiments, the lower legs of two volunteers are cooled from outside. Images are acquired with a spin-echo sequence (1.5T, TR=1200 ms, TE=10 ms). A rise in signal intensity in the muscle with falling skin temperature is observed, particularly in more peripheral muscle layers. This study shows that spin-echo sequences can be used to monitor temperature changes and temperature differences in living muscle tissue.     

甲基强的松龙对低温保存大鼠肝脏的保护作用

应用Ｗｉｓｔａｒ大鼠肝脏离体灌流模型，用ＣＭＵ—１号液，含有甲基强的松龙的ＣＭＵ—１号液，以及缺血前预用甲基强的松龙后再用ＣＭＵ—１号液分别对肝脏进行灌洗保存。检测ＬＤＨ、ＡＬＴ、肝组织匀浆ＳＯＤ活性和ＭＤＡ含量，并观察肝组织结构。结果表明：甲基强的松龙对低温保存的离体大鼠肝脏具有保护作用     

Regulation of local sweating in sleep-deprived exercising humans

Summary Thermoregulatory sweating [total body (m _sw,b), chest (m _sw,c) and thigh (m _sw,t) sweating], body temperatures [oesophageal (T _oes) and mean skin temperature (T _sk)] and heart rate were investigated in five sleep-deprived subjects (kept awake for 27 h) while exercising on a cycle (45 min at approximately 50% maximal oxygen consumption) in moderate heat (T _air andT _wall at 35° C. Them _sw,c andm _sw,t were measured under local thermal clamp (T _sk,1), set at 35.5° C. After sleep deprivation, neither the levels of body temperatures (T _oes,T _sk) nor the levels ofm _{sw, b},m _{sw, c} orm _{sw, t} differed from control at rest or during exercise steady state. During the transient phase of exercise (whenT _sk andT _sk,1 were unvarying), them _{sw, c} andm _{sw, t} changes were positively correlated with those ofT _oes. The slopes of them _{sw, c} versusT _oes, orm _{sw, t} versusT _oes relationships remained unchanged between control and sleep-loss experiments. Thus the slopes of the local sweating versusT _oes, relationships (m _{sw, c} andm _{sw, t} sweating data pooled which reached 1.05 (SEM 0.14) mg·cm^–2·min^–1°C^–1 and 1.14 (SEM 0.18) mg·cm^–2·min^–1·°C^–1 before and after sleep deprivation) respectively did not differ. However, in our experiment, sleep deprivation significantly increased theT _oes threshold for the onset of bothm _{sw, c} andm _{sw, t} (+0.3° C,P<0.001). From our investigations it would seem that the delayed core temperature for sweating onset in sleep-deprived humans, while exercising moderately in the heat, is likely to have been due to alterations occurring at the central level.     

Toe temperature versus transcutaneous oxygen tension monitoring during acute circulatory failure

Measurements of toe temperature and transcutaneous PO₂ (P_tcO₂) have been both suggested for non-invasive assessment of peripheral blood flow in acute circulatory failure. The underlying principle of the two methods is that cutaneous vasoconstriction occurs early when tissue perfusion is altered. In 15 patients, we compared the two measurements during cardiogenic shock (27 measurements) or septic shock (29 measurements). Toe-ambiant temperature gradient and P_tcO₂ correlated well together (r=0.66, p(0.001) especially in hyperkinetic septic shock (r=0.79, p(0.001). In cardiogenic shock, toe-ambiant temperature correlated well with cardiac index (r=0.63), stroke index (r=0.64) and oxygen transport (r=0.65), and these correlations were stronger than for P_tcO₂. In septic shock, both techniques were poor indicators of blood flow indexes but P_tcO₂ rather correlated with arterial pressure (r=0.66) and left ventricular work (r=0.66). Trend evaluation of data revealed in cardiogenic shock that the increase in toe temperature usually preceded the increase in P_tcO₂. Since measurement of P_tcO₂ is technically more complicated, correlates less well with standard hemodynamic parameters and later reflects cardiovascular improvement, it has no advantage over measurement of toe temperature in circulatory shock. In cardiogenic shock, measurements of toe temperature can reliably track cardiac output changes. In septic states, however, non-invasive assessment of skin perfusion is of limited interest.     

Effect of psychotomimetics and some putative anxiolytics on stress-induced hyperthermia

Summary Stress-induced hyperthermia (SIH), which is seen in the last mice removed from the cage, is a novel animal model sensitive to anxiolytic drugs. SIH is antagonized by CL 218872 (25 and 50 mg/kg, os), by tracazolate (5 and 7.5 mg/kg, ip) and by 2-AP-5 (50 and 100 mg/kg, ip). At higher dose, CL 218872 (100 mg/kg, os) and tracazolate (12.5 mg/kg, ip) lose their activity.PK 9084 (5–40 mg/kg, ip) and CGS 9896 (2–20 mg/kg, both ip and os) were also ineffective in preventing SIH. The anti-hyperthermic effect of CL 218872 (25 mg/kg) and tracazolate (7.5 mg/kg) was blocked by the benzodiazepine antagonist Ro 15–1788 (15 mg/kg). CGS 9896 (10 mg/kg, os) also reversed the effect of CL 218872 (25 mg/kg) on SIH.Differently from anxiolytics, MK-801 (0.5–1 mg/kg, os), PCP (2.5 mg/kg, ip) and d-amphetamine (10 mg/kg, ip) evoked hyperthermia in the first set of mice and prevented a further stress-induced rise of body temperature in the last set of mice.     

Buspirone does not produce a 5-HT1A-mediated decrease in temperature in man

Summary Buspirone, a putative serotonin (5-HT)_1A partial agonist, did not produce hypothermia in 17 normal volunteers in a placebo controlled, single blind study. Thus, buspirone may be a weaker agonist at those 5-HT_1A receptors which mediate hypothermia compared to ipsapirone or gepirone, two other 5-HT_1A partial agonists which have been reported to produce hypothermia by a 5-HT_1A-mediated mechanism.     

Flavor preference conditioning by oral self-administration of ethanol

 Oral self-administration and operant tasks have been used successfully to confirm ethanol′s positive reinforcing effects in rats. However, in flavor conditioning tasks, ethanol is typically found to have aversive effects. The present studies explored this apparent paradox by examining the change in value of a flavor paired with orally self-administered ethanol in two different limited-access procedures. Rats were food-deprived and trained to drink (experiment 1) or to barpress for (experiment 2) 10% (v/v) ethanol during daily 30-min sessions using prandial initiation techniques. All rats were then exposed to a differential flavor conditioning procedure in which banana or almond extract was added to the drinking solution. One flavor (counterbalanced) was always mixed with ethanol (CS+), whereas the other flavor was mixed with water (CS–). By the end of conditioning, rats in both experiments drank more flavored ethanol than flavored water, confirming ethanol’s efficacy as a reinforcer. Moreover, barpress rates for CS+ exceeded those for CS– in the operant task. Ethanol doses self-administered in final sessions averaged about 1 g/kg. The effect of the flavor-ethanol contingency was assessed in preference tests that offered a choice between the two flavor solutions without ethanol. In both experiments, subjects developed a preference for the flavor that had been paired with ethanol. Thus, the outcome of flavor conditioning was consistent with that of the oral self-administration tasks in providing evidence of ethanol’s rewarding effects. These experiments confirm and extend previous studies showing that flavor aversion is not the inevitable result of flavor-ethanol association in rats. It seems likely that ethanol’s nutrient and pharmacological effects both contributed to the development of conditioned flavor preference. Received: 15 February 1997 / Final version: 11 June 1997     

Seasonal covariation of the circadian phases of rectal temperature and slow wave sleep onset

There is a scarcity of well-controlled studies of the seasonal variation in circadian rhythmicity. In the present study, the circadian phase of rectal temperature and the onset of slow wave sleep were studied in a series of twelve 24-h experiments, one each month of the year, for six healthy subjects under controlled conditions in a climatic chamber. In winter, as compared with summer, the average circadian rhythm of rectal temperature was phase delayed by 45 min, and the average onset of slow wave sleep was phase delayed by 40 min. The temporal relationship between the circadian phase of rectal temperature and the timing of slow wave sleep was maintained throughout the year. Habitual rising and retiring times covaried as well. Furthermore, the circadian rhythm of rectal temperature followed the timing of the photoperiod across the year, but had a much smaller range of seasonal variation. Apparently, the seasonal variation in the photoperiodic zeitgeber is largely compensated for by the stabilizing influence of secondary zeitgebers. However, in healthy subjects some effect of photoperiodic variation can still be observed.