地塞米松治疗创伤性脑水肿时测定其在血及脑组织中含量

测定了大剂量（５ｍｇ／ｋｇ体重）地塞米松（Ｄｅｘ）与小剂量（０．５ｍｇ／ｋｇ）Ｄｅｘ治疗创伤性脑水肿血及脑组织中Ｄｅｘ浓度的变化。结果提示，大鼠创伤性脑水肿后应用大剂量Ｄｅｘ，血中最高汲工为１０＾－６ｍｏｌ／Ｌ，而应用小剂量Ｄｅｘ后血中最高浓度为１０＾－７ｍｏｌ／Ｌ。应用大剂量Ｄｅｘ治疗颅脑外伤病人时，血中最高浓度为１０＾－６ｍｏｌ／Ｌ。由于糖皮质激素存在高亲和力结合位点（１０＾－８ｍｏｌ／Ｌ）和     

运动引起的脑与血浆亮脑啡肽变化的初步观察

<正> 脑啡肽是近年发现的一类神经调制物质—呐啡肽的一种,由中间神经元释放后作用在突触部位,在心血管、呼吸、内分泌及运动等多方面显示生理功能。脑啡肽还在肾上腺髓质嗜铬细胞内与儿茶酚胺共存并共同释放入     

+Gz重复暴露对大鼠脑组织c-fos、c-jun和神经生长因子基因表达的影响

为了解＋Ｇｚ重复暴露后大鼠脑组织ｃ－ｆｏｓ、ｃ－ｊｕｎ和神经生长因子基因表达的变化,探讨它们在＋ＧＫ致脑损伤中的作用和意义,用半定量反转录聚合酶链反应检测方法检测＋Ｇｚ重复暴露后大鼠脑组织ｃ－ｆｏｓ、ｃ－ｊｕｎ和ＮＧＦ ｍＲＮＡ表达水平。     

运动对血浆心钠素影响的初步探讨

本文通过观察中长跑运动员极限运动下血浆心钠素的变化,探索运动对心脏内分泌的影响。实验结果提示了运动时由于血液动力学和神经生化变化引起血浆心钠素增加,有训练运动员极限运动后心钠素明显增加,与良好的心脏功能和运动能力有关。     

Degradation of visual pursuit during sustained +3 Gz acceleration.

BACKGROUND: During positive acceleration, there is a diminished flow of blood to all regions above the heart. This is manifested by the commonly described loss of peripheral vision, greyout and blackout, which have been investigated extensively. The ability to select appropriate scanning patterns and to efficiently process visual information is one of the important determinants of scan effectiveness. This study investigates the performance of the smooth pursuit system under sustained +3 Gz before any signs of loss of vision. METHODS: Eleven subjects with no known oculomotor and vestibular anomalies participated in the study. Horizontal and vertical pursuit at amplitudes of 10 and 20 degrees were investigated in each of the subjects over 4 separate days. During each test session, pursuit targets of a predictable sine wave, oscillating at 0.2, 0.4, 0.8, 1.2 and 1.6 Hz were presented to the subjects in a random order. Horizontal and vertical eye movements were recorded using the El-Mar eye tracking system. The subjects were tested in 4 trials: 1) at 1 G before exposure to increased acceleration; 2) during sustained +3 Gz; 3) immediately after the +3 Gz exposure; and 4) 5 min after the +3 Gz exposure. RESULTS: Breakdown in smooth pursuit in response to horizontal and vertical sinusoidal stimuli during +3 Gz is indicated by a statistically significant decrease in gain and an increase in phase lag (p < 0.01). This is most obvious when the stimulus frequency is greater than 0.4 Hz. Qualitatively, the pursuit response during acceleration was ataxic and disorganized in appearance. CONCLUSION: It is postulated that degradation of pursuit gain and phase could be due to central hypoxia, and that the increase of G loading on the vestibular system could affect the neural integration of the pursuit signal in the vestibular nuclei with its direct output to the oculomotor system.     

Heart biochemical responses in miniature swine subjected to +Gz acceleration.

Myocardial biochemical systems which are sensitive to hypoxic and ischemic insult were studied to determine the possible etiology of ventricular endocardial hemorrhage in miniature swine following +GZ stress. Unanesthetized animals were subjected to a single, 120-s +9 GZ acceleration. Approximately 1-2 h following +GZ exposure, the animals were anesthetized and the hearts removed for analyses. Acceleration exposure resulted in the loss of acid phosphatase enzyme activity from the membrane-bound lysosomal fraction with concomitant increased activity in the soluble fraction. This suggests that lysosomal membrane integrity had been disrupted. Mitochondrial preparations from +GZ-stressed hearts exhibited marked increases in active respiratory rate and rate of calcium transport while oxidative phosphorylation efficiency was unchanged. The results clearly indicate that +GZ acceleration is capable of altering myocardial biochemical systems. However, the results tend to suggest that these alterations in cellular processes may be mediated by influences other than hypoxia or ischemia.     

Isometric force production in experienced fighter pilots during +3 Gz centrifuge acceleration

INTRODUCTION: Previously, we have shown that na?ve subjects produce exaggerated isometric forces when exposed to increased acceleration (+Gz) for the first time. The present study investigates whether +G,-experienced PA-200 Tornado pilots show similar deficits. METHODS: Experiments were conducted in the stationary (+1 Gz) or rotating (+3 Gz) gondola of a human-rated centrifuge. With their dominant hand, seven pilots produced visually prescribed forces of specific direction and magnitude using an isometric joystick. In practice trials, subjects received continuous visual feedback about their performance, while in test trials they did not. RESULTS: Peak forces during test trials were significantly higher in +3 Gz than in +1 Gz, although this increase of about 25% referring to the +1 Gz value was somewhat smaller in pilots than in nonpilot controls (increase of about 36%). DISCUSSION: Since pilots' responses were exaggerated in +3 Gz, it seems that frequent exposure to varying +Gz levels is not sufficient for a profound adaptation of force-producing mechanisms to +3 Gz. In consequence, pilots' performance on isometric tasks could be compromised during flight maneuvers in +Gz.     

异丙酚对脑创伤家兔血及脑脊液神经元特异性烯醇化酶含量的影响

通过观察异丙酚对脑创伤家兔血及脑脊液神经元特异性烯醇酶 (NSE)含量的影响 ,探讨异丙酚的脑保护作用。用 2 0只健康雄性新西兰家兔建立稳定的脑创伤模型 ,随机分为对照组和异丙酚组 (n=10 ) ,分别于伤前 ,伤后 4、2 4、4 8、72h和 1周测定血和脑脊液NSE含量。结果显示 ,对照组血NSE含量于伤后 2 4、4 8、72h ,脑脊液NSE含量于伤后 4、2 4、4 8、72h和 1周明显高于伤前 (P <0 0 5 ,P <0 0 1) ;异丙酚组血NSE在伤后 4 8、72h和 1周 ,脑脊液NSE含量在伤后 2 4、4 8、72h和 1周明显低于对照组 (P <0 0 5 )。表明异丙酚能明显降低脑创伤家兔血和脑脊液NSE含量 ,具有一定的脑保护作用     

若干治疗措施对γ线照射狗血内纤维蛋白原及其降解产物的影响

在5.5Gy照射狗上观察了早期几种治疗措施对血中纤维蛋白原及其降解产物(FDP)的影响.综合治疗、抗出血和抗感染等措施在延迟照后纤维蛋白原第2上升峰起始时间和降低其上升程度都有不同影响.在减轻照后FDP的变化方面,止血药的使用早用比晚用好.上述结果说明,血中纤维蛋白原含量的变化对分析某些治疗措施效果还是有用的.     

bFGF及丹参对＋Gz重复暴露大鼠脑组织中iNOS mRNA表达影响

为了解诱导型一氧化氮合酶(iNOS)在正加速度（ Gz）重复暴露大鼠脑组织中表达的变化,探讨碱性成纤维细胞生长因子（bFGF）及丹参对反复高＋Gz暴露致脑损伤的防护作用,用半定量反转录聚合酶链反应（RT－PCR）方法检测＋Gz重复暴露大鼠和bFGF、丹参处理再暴露大鼠脑组织中iNOSmRNA表达变化。结果＋Gz重复暴露组可见明显的iNOS mRNA表达增高,而bFGF和丹参能阻断这种iNOS表达变化。表达＋Gz重复暴露可引起大鼠脑内iNOSmRNA表达变化,它可能在反复高＋Gz暴露致脑损伤中起重要作用,而bFGF和丹参对＋Gz暴露所致的脑损伤具有防护作用。     

Regional cerebral blood flow in conscious miniature swine during high sustained +Gz acceleration stress

The two major factors limiting performance during high +Gz acceleration stress are loss of vision, and loss of consciousness. These symptoms are believed to occur as a result of insufficient blood flow to the retina and brain. This study was conducted to determine the effects of +Gz stress on regional cerebral blood flow. Cerebral blood flow (CBF) was measured in 22 conscious, female, miniature swine with the radio-labeled microsphere technique. Acceleration exposures consisted of 60-S plateaus at +3Gz, +5Gz or +7Gz. Microsphere infusions were made before, during, 1.0-6.0 min after, and 10 min after +Gz. Blood flow to the retina was significantly decreased during exposure to +5Gz and ceased during exposure to +7Gz stress. Mean, resting control CBF was 34 +/- 4 ml/min/100 g. Exposure to +3Gz and +5Gz had no significant effect on CBF. Exposure to +7Gz appeared to cause a redistribution of CBF, with blood flow to the brain stem being preserved and flow to the cerebrum being diminished.     

Hemodynamic responses to seated and supine lower body negative pressure: comparison with +Gz acceleration.

Hemodynamic changes between upright and supine lower body negative pressure (LBNP) to levels of -70 mm Hg were compared in 8 subjects (5 males, 3 females) and correlated with their findings during simulated Shuttle reentry acceleration with a slow onset rate of 0.002 G/s (1,020 s to peak +2 Gz) and during gradual onset exposures (0.03 G/s) to +3 Gz and +4 Gz. Six of the 8 subjects were able to tolerate 2 min at peak +2 Gz, 2-5 min at +3 Gz, and 1-2 min at +4 Gz. Heart rate (HR) at any given level of upright LBNP regularly exceeded supine levels. HR change at -50 mm Hg in upright subjects (+47.7 bpm from 74.1 +/- 1.9 (M +/- S.E.) bpm, control) was 2.6 times greater than in supine subjects (+18.3 bpm from 64.8 +/- 2.8 bpm, control). HR values at -40 mm Hg supine (73.7 +/- 2.6) matched seated upright pre-LBNP control levels (74.1 +/- 1.9 bpm), while values at -70 mm Hg supine (102.5 +/- 4.4 bpm) were not significantly different from those at -40 mm Hg upright (103.1 +/- 4.0 bpm). Peak HR during +3 Gz (145.8 +/- 7.7 bpm) and +4 Gz (152.3 +/- 6.5 bpm) significantly exceeded recorded supine and upright LBNP levels, whereas values at +2 Gz (104.8 +/- 5.5 bpm) closely matched those at -40 mm Hg upright (103.1 +/- 4.0 bpm) and -70 mm Hg supine (102.5 +/- 4.4 bpm). Supine LBNP HR changes in this relatively small group of subjects closely matched those previously reported in the literature.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of physical training in cool and hot environments on +Gz acceleration tolerance in women

Rectal temperature (Tre), sweat rate, plasma volume (PV), peak oxygen uptake (peak VO2), and relaxed +Gz acceleration tolerance (0.5 G X min-1 linear to grayout) were measured in 15 healthy women 21-41 years old before and after submaximal isotonic exercise training for 2 h X d-1 on a cycle ergometer. The women had 2 weeks of acceleration runs and Vo2 testing, followed by 8 d of exercise training, post-training acceleration runs on day 9, and peak Vo2 tests on day 10. They were divided into three groups: an exercise (heat) group, ambient temperature (Ta) 40.6 degrees C, relative humidity (rh) 42%, and a peak Vo2 of 52%; an exercise (cool) group, Ta = 18.7 degrees, rh = 48%, and Vo2 peak = 55%; and a sedentary control (cool) group. There was no change in peak ventilation, peak heart rate (HR), peak Vo2, or in resting PV in any group after training. Heart rate and Tre were significantly lower after training in both cool and hot environments; HR by 17 b X min-1 (p less than 0.05) and 27 b X min-1 (p less than 0.05), respectively, and Tre by 0.4 degrees C (p less than 0.05) and 0.4 degrees C (p less than 0.05), respectively. Sweat rates were not different in any group. In all groups, acceleration tolerances were not different after training; they ranged from 3.5 to 3.8 G (373 - 410 s). The loss (shift) in PV during acceleration ranged from -5.8% to -10.3% (nonsignificant).(ABSTRACT TRUNCATED AT 250 WORDS)     

A near-infrared spectrophotometric method for studying brain O2 sufficiency in man during +Gz acceleration

A technique for the noninvasive monitoring of cerebral oxygen status was evaluated on volunteer subjects on the USAF School of Aerospace Medicine centrifuge. By using multiwavelength near-infrared spectrophotometry, the instrumentation measured changes in the quantities of reduced and oxygenated hemoglobin (and their sum, an indicator of cerebral blood volume), and the quantity of oxidized cytochrome c oxidase within the forebrain. Tests used acceleration of up to 9 G with onset rates from 0.1 to 5.0 G.s-1, anti-G suits and straining maneuvers, and hyperoxic and hypoxic breathing mixtures. In general, +Gz acceleration produced a fall in blood volume within the cerebral microcirculation with a relative increase in the content of reduced hemoglobin and a tendency towards reduction of cytochrome c oxidase. These findings are discussed in relation to accepted changes in arterial blood pressure, cerebral blood flow, and arterial oxygen saturation caused by acceleration exposure.     

脑损伤后脑与血中钙和钙调素含量变化及氢溴酸山莨菪碱对其影响

采用大鼠脑落体损伤模型,分别检测脑损伤后不同时间脑组织水含量、脑皮质和血中钙及钙调素(CaM)含量,并应用氢溴酸山莨菪碱治疗。结果:(1)脑损伤后脑及血中钙含量均有增高,以脑皮质钙含量增高较为明显,伤后48h达24.12±10.22mmol/kg干脑,约为对照值的2倍;(2)脑皮质及血中CaM含量均有较明显升高,伤后48h达峰值,分别为对照值的2.6倍和2.8倍;(3)脑损伤后脑白质水含量显著增加,其变化规律与脑组织中钙及CaM相一致;(4)应用氢溴酸山莨菪碱后钙及CaM含量显著降低,脑水肿明显减轻。     

血浆ACTH、血清皮质醇测定对肾上腺皮质功能减退的诊断价值

本文报告原发肾上腺皮质功能减退(PAF)患者13例、继发肾上腺皮质功能减退(SAF)患者31例及正常人42名血浆ACTH及血清皮质醇测定的结果。血浆ACTH:PAF组显著高于正常组;SAF组显著低于正常组;PAF组与SAF组或正常组无重叠,但SAF组与正常组有较多重叠(83.9％)。血清皮质醇:PAF组、SAF组均显著低于正常组;PAF和SAF两组相似,但与正常组有少量重叠(13.6％),其中14例SAF、3例PAF和13名正常人做了氨基导眠能试验。SAF和正常人两组服药后血浆ACTH的重叠现象消失。本文结果表明,血清皮质醇是诊断肾上腺皮质功能减退的直接证据。但不能鉴别PAF和SAF,而血浆ACTH可以鉴别两者,氨基导眠能试验有助于鉴别SAF和正常人。     

运动性疲劳与脑中γ-氨基丁酸

<正> 关于运动性疲劳产生的机理,目前大多数学者认为与运动的类型有关。如短时间剧烈运动时出现的疲劳,往往以肌肉中能源物质的消耗及乳酸等代谢产物的堆积这些外周因素为主,长时间中等强度的运动产生的疲劳,则往往以中枢神经系统出现保护性抑制的中枢因素     

运动、营养与自由基代谢Ⅰ.游泳对小鼠肝脑组织内自由基代谢的影响

本文实验结果显示,小鼠在90分钟游泳后,肝组织内过氧化脂质LPO明显增加,超氧化物歧化酶SOD活性明显增高,而且游泳后在肝组织中出现安静时没有的明显的自由基群(g_(11):2.0424)。