急性高原暴露后左心功能变化及与急性高原病的关系

目的：研究青年男性由平原急进高原后心脏血流动力学变化及其与急性高原病的关系。方法：分别检测218名健康青年男性在平原及急进高原24h内的血压、心卒和血氧饱和度,使用彩色多普勒超声仪检测左心功能;根据路易斯湖评分标准将受试者分为急性高原病纽（AMS组）和无急性高原病组（无AMS组）。结果：急性高原暴露后心率、舒张压、平均动脉压、左室射血分数、每搏输出量、每博指数、心输出量、心脏指数显著增加（P〈0．05）,血氧饱和度、左室收缩末容积则显著降低（P〈0．05）;急进高原后AMS组心率、收缩压、平均动脉压显著高于无AMS组（P〈0．05）,每博指数、左室舒张末容积显著低于无AMS组（P〈0．05）。结论：健康男性青年急性高原暴露后左心室收缩功能增强,左室舒张末容积、心率、每博指数可能作为预测急性高原病的参考指标。     

急进和渐进西藏对南极考察昆仑站预选队员心血管功能及其应激因子的影响*

目的: 分析急进和渐进西藏高原对拟进入中国南极考察昆仑站的第31、32和 33次预选队员的心血管功能及其相关应激因子水平的影响,为选拔合格的内陆考察队员提供科学依据。方法: 以 2014～2016 年第 31、32 和33次队共 85名中国南极考察昆仑站预选队员为研究对象,依据进入高原方式分为乘飞机急进高原组(急进组,n=55)和乘火车渐进高原组(渐进组,n=30),分别在上海出发(海拔 4 m)、到达拉萨(海拔 3 658 m)和进入更高海拔的羊八井(海拔 4 300 m)3个时间点,采用心功能仪和心电图仪动态检测预选队员的心血管功能,并同步采集队员的唾液样本,采用 ELISA法检测唾液中应激因子睾酮(T)、皮质醇(COR)和免疫球蛋白A(IgA)水平。结果: 与海拔 4 m 相比,两组队员在到达海拔 3 658 m、4 300 m 高原时,心率(HR)显著升高(P＜0.05),指端静脉血氧饱和度(SpO₂)显著下降(P＜0.05),但两组间在相同海拔高度上无显著差异;两组间心电传导异常率无显著差异;与海拔4 m相比,到达 3 658 m和 4 300 m处两组队员的血压均显著升高(P＜0.05),部分心肌收缩和泵血功能指标均显著降低(P＜0.05),但由于心率增加代偿,心输出量(CO)无显著变化。在海拔4 300 m时,急进组的肺水指数(TFC)显著高于渐进组(P＜0.01)。进入高原后与出发水平的差值比较,两组在海拔3 658 m 处 T变化量无显著性差异(P＞0.05),急进组 COR 和IgA变化量显著高于渐进组(P＜0.05);在海拔 4 300 m 处急进组 IgA变化量显著高于渐进组(P＜0.05)。结论: 对比渐进高原,急进高原对南极考察昆仑站预选队员的心血管功能及唾液中的应激激素和免疫球蛋白水平均有更明显影响。提示应在岗前严格选拔能适应南极昆仑站低氧环境的考察队员,保障南极考察队员身心健康,确保南极考察任务顺利实施。     

Identification of susceptibility to acute mountain sickness by detecting vascular tone using a photoplethysmographic sensor

Objective: Vascular tone had shown the potential susceptibility to acute mountain sickness(AMS), however the detailed tendency has not been studied. Methods: Vascular tone, SpO_2 and Rate pressure product(RPP) were studied in seventeen healthy subjects before and after rapid ascent from sea level to 3658 m. Human acute mountain sickness was evaluated by the Lake Louise Score(LLS). Results: Nine of the seventeen participants were diagnosed with AMS. On initial exposure, there was a significant decrease in vascular tone between subjects with and without AMS. Significance was also found in the decrease of SpO_2 before and after rapid ascent but the differences between subjects with and without AMS did not reach significance during the initial phase. Conclusions: Vascular tone on initial exposure in response to rapid ascent is a possible sign of susceptibility to AMS. Conclusion: measurement of vascular tone using a wearable sensor throughout the acute phase response will provide numerical values of pathophysiology throughout the development of AMS.     

Atrial natriuretic peptide in acute mountain sickness

To test the hypothesis that elevated atrial natriuretic peptide (ANP) may be involved in altered fluid homeostasis at high altitude, we examined 25 mountaineers at an altitude of 550 m and 6, 18, and 42 h after arrival at an altitude of 4,559 m, which was climbed in 24 h starting from 3,220 m. In 14 subjects, symptoms of acute mountain sickness (AMS) were absent or mild (group A), whereas 11 subjects had severe AMS (group B). Fluid intake was similar in both groups. In group B, urine flow decreased from 61 +/- 8 (base line) to 36 +/- 3 (SE) ml/h (maximal decrease) (P less than 0.05) and sodium excretion from 7.9 +/- 0.9 to 4.6 +/- 0.7) mmol.l-1.h-1 (P less than 0.05); ANP increased from 31 +/- 4 to 87 +/- 26 pmol/l (P less than 0.001), plasma aldosterone from 191 +/- 27 to 283 +/- 55 pmol/l (P less than 0.01 compared with group A), and antidiuretic hormone (ADH) from 1.0 +/- 0.1 to 2.9 +/- 1.2 pmol/l (P = 0.08 compared with group A). These variables did not change significantly in group A, with the exception of a decrease in plasma aldosterone from 189 +/- 19 to 111 +/- 17 pmol/l (P less than 0.01). There were no measurable effects of elevated ANP on natriuresis, cortisol, or blood pressure. The reduced diuresis in AMS may be explained by increased plasma aldosterone and ADH overriding the expected renal action of ANP. The significance of elevated ANP in AMS remains to be established.(ABSTRACT TRUNCATED AT 250 WORDS)     

The body weight loss during acute exposure to high-altitude hypoxia in sea level residents

Weight loss is frequently observed after acute exposure to high altitude. However, the magnitude and rate of weight loss during acute exposure to high altitude has not been clarified in a controlled prospective study. The present study was performed to evaluate weight loss at high altitude. A group of 120 male subjects [aged (32±6) years] who worked on the construction of the Golmud-Lhasa Railway at Kunlun Mountain (altitude of 4 678 m) served as volunteer subjects for this study. Eighty-five workers normally resided at sea level (sea level group) and 35 normally resided at an altitude of 2 200 m (moderate altitude group). Body weight, body mass index (BMI), and waist circumference were measured in all subjects after a 7-day stay at Golmud (altitude of 2 800 m, baseline measurements). Measurements were repeated after 33-day working on Kunlun Mountain. In order to examine the daily rate of weight loss at high altitude, body weight was measured in 20 subjects from the sea level group (sea level subset group) each morning before breakfast for 33 d at Kunlun Mountain. According to guidelines established by the Lake Louise acute mountain sickness (AMS) consensus report, each subject completed an AMS self-report questionnaire two days after arriving at Kunlun Mountain. After 33-day stay at an altitude of 4 678 m, the average weight loss for the sea level group was 10.4% (range 6.5% to 29%), while the average for the moderate altitude group was 2.2% (-2% to 9.1%). The degree of weight loss (Δ weight loss) after a 33-day stay at an altitude of 4 678 m was significantly correlated with baseline body weight in the sea level group (r=0.677, P<0.01), while the correlation was absent in the moderate altitude group (r=0.296, P>0.05). In the sea level subset group, a significant weight loss was observed within 20 d, but the weight remained stable thereafter. AMS-score at high altitude was significantly higher in the sea level group (4.69±2.48) than that in the moderate altitude group (2.97±1.38), and was significantly correlated with baseline body weight. These results indicate that (1) the person with higher body weight during stay at high altitude loses more weight, and this is more pronounced in sea level natives when compared with that in moderate altitude natives; (2) heavier individuals are more likely to develop AMS than leaner individuals during exposure to high-altitude hypoxia.     

Early fluid retention and severe acute mountain sickness.

Field studies of acute mountain sickness (AMS) usually include variations in exercise, diet, and environmental conditions over days and development of clinically apparent edemas. The purpose of this study was to clarify fluid status in persons developing AMS vs. those remaining without symptoms during simulated altitude with controlled fluid intake, diet, temperature, and without exercise. Ninety-nine exposures of 51 men and women to reduced barometric pressure (426 mmHg = 16,000 ft. = 4,880 m) were carried out for 8-12 h. AMS was evaluated by Lake Louise (LL) and AMS-C scores near the end of exposure. Serial measurements included fluid balance, electrolyte excretions, and plasma concentrations, regulating hormones, and free water clearance. Comparison between 16 subjects with the lowest AMS scores near the end of exposure ("non-AMS": mean LL = 1.0, range = 0-2.5) and 16 others with the highest AMS scores ("AMS": mean LL = 7.4, range = 5-11) demonstrated significant fluid retention in AMS beginning within the first 3 h, resulting from reduced urine flow. Plasma Na+ decreased significantly after 6 h, indicating dilution throughout the total body water. Excretion of Na+ and K+ trended downward with time in both groups, being lower in AMS after 6 h, and the urine Na+-to-K+ ratio was significantly higher for AMS after 6 h. Renal compensation for respiratory alkalosis, plasma renin activity, aldosterone, and atrial natriuretic peptide were not different between groups, with the latter tending to rise and aldosterone falling with time of exposure. Antidiuretic hormone fell in non-AMS and rose in AMS within 90 min of exposure and continued to rise in AMS, closely associated with severity of symptoms and fluid retention.     

盐酸芬太尼与麻黄碱对微管可视无痛人流术患者麻醉效果 的比较研究

目的:对比评价盐酸芬太尼与麻黄碱对于微管可视无病人流术患者麻醉后术中血流动力学、脑电参数以及术后苏醒时间的变化,为微管可视无病人流术合理选择麻醉剂提供数据依据.方法:选择进入我院进行微管可视无痛人流术患者180例,随机分为2组,每组90例,分别为盐酸芬太尼组与麻黄碱组.观察记录麻醉后患者术中心率(Heart rate,HR),血氧饱和度(Pulse oximetry,SpO2),收缩压(Systolic blood pressure,SBP),舒张压(Diastolic blood pressure,DBP),脑电双频指数(Bispectral index,BIS)以及术后苏醒时间(Recovery time,RT),并进行统计学分析.结果:1.盐酸芬太尼组患者术中BIS指数显著低于麻黄碱组(P＜0.05),RT 显著低于麻黄碱组(P＜0.05).2.盐酸芬太尼组与麻黄碱组的HR,SpO2,SBP,DBP比较均无统计学差异(P＞0.05).结论:说明盐酸芬太尼在微管可视无痛人流术中麻醉效果优于麻黄碱.     

MtDNA haplogroups M7 and B in southwestern Han Chinese at risk for acute mountain sickness

We conducted a case-control study to investigate the association of mitochondrial DNA (mtDNA) haplogroups with acute mountain sickness (AMS) in Han Chinese from southwestern (SW) China. Pearson's chi-square test or Fisher's exact test revealed significant reduction of mtDNA haplogroups D and M9, while a significant increase of haplogroup M7 in AMS subjects compared with non-AMS subjects. The multivariate logistic regression analysis after adjustment for body mass index (BMI), a risk factor of AMS in the present study, showed that both D and M9 were associated with significantly decreased risk of AMS, while M7 was associated with a significantly increased risk of AMS (OR=0.605, p=0.000; OR=0.037, p=0.001, and OR=2.419, p=0.001, respectively). In addition, further analysis stratified by the AMS severities indicated that haplogroup B was correlated with a 2.41-folds increased risk of developing severe AMS (95%C.I=1.288-4.514, p=0.006). Our findings provide evidence that, in SW Han Chinese, mtDNA haplogroups D and M9 are related to individual tolerance to AMS, while haplogroups M7 and B are risk factors for AMS.     

Enhanced exercise-induced rise of aldosterone and vasopressin preceding mountain sickness

A possible contribution of exercise to the fluid retention associated with acute mountain sickness (AMS) was investigated in 17 mountaineers who underwent an exercise test for 30 min on a bicycle ergometer with a constant work load of 148 +/- 9 (SE) W at low altitude (LA) and with 103 +/- 6 W 4-7 h after arrival at 4,559 m or high altitude (HA). Mean heart rates during exercise at both altitudes and during active ascent to HA were similar. Exercise-induced changes at LA did not differ significantly between the eight subjects who stayed well and the nine subjects who developed AMS during a 3-day sojourn at 4,559 m. At HA, O2 saturation before (71 +/- 2 vs. 83 +/- 2%, P less than 0.01) and during exercise (67 +/- 2 vs. 72 +/- 1%, P less than 0.025) was lower and exercise-induced increase of plasma aldosterone (617 +/- 116 vs. 233 +/- 42 pmol/l, P less than 0.025) and plasma antidiuretic hormone (23.8 +/- 14.4 vs. 3.4 +/- 1.8 pmol/l, P less than 0.05) was greater in the AMS group, whereas exercise-induced rise of plasma atrial natriuretic factor and changes of hematocrit, potassium, and osmolality in plasma were similar in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of repeated normobaric hypoxia exposures during sleep on acute mountain sickness, exercise performance, and sleep during exposure to terrestrial altitude

There is an expectation that repeated daily exposures to normobaric hypoxia (NH) will induce ventilatory acclimatization and lessen acute mountain sickness (AMS) and the exercise performance decrement during subsequent hypobaric hypoxia (HH) exposure. However, this notion has not been tested objectively. Healthy, unacclimatized sea-level (SL) residents slept for 7.5 h each night for 7 consecutive nights in hypoxia rooms under NH [n = 14, 24 ± 5 (SD) yr] or "sham" (n = 9, 25 ± 6 yr) conditions. The ambient percent O(2) for the NH group was progressively reduced by 0.3% [150 m equivalent (equiv)] each night from 16.2% (2,200 m equiv) on night 1 to 14.4% (3,100 m equiv) on night 7, while that for the ventilatory- and exercise-matched sham group remained at 20.9%. Beginning at 25 h after sham or NH treatment, all subjects ascended and lived for 5 days at HH (4,300 m). End-tidal Pco(2), O(2) saturation (Sa(O(2))), AMS, and heart rate were measured repeatedly during daytime rest, sleep, or exercise (11.3-km treadmill time trial). From pre- to posttreatment at SL, resting end-tidal Pco(2) decreased (P < 0.01) for the NH (from 39 ± 3 to 35 ± 3 mmHg), but not for the sham (from 39 ± 2 to 38 ± 3 mmHg), group. Throughout HH, only sleep Sa(O(2)) was higher (80 ± 1 vs. 76 ± 1%, P < 0.05) and only AMS upon awakening was lower (0.34 ± 0.12 vs. 0.83 ± 0.14, P < 0.02) in the NH than the sham group; no other between-group rest, sleep, or exercise differences were observed at HH. These results indicate that the ventilatory acclimatization induced by NH sleep was primarily expressed during HH sleep. Under HH conditions, the higher sleep Sa(O(2)) may have contributed to a lessening of AMS upon awakening but had no impact on AMS or exercise performance for the remainder of each day.     

Accuracy of pulse oximetry to estimate HbO2 fraction of total Hb during exercise

The accuracy of two pulse oximeters (Ohmeda 3700 and Biox IIa) was evaluated during cycle ergometer incremental exercise in 10 healthy subjects. The exercise protocol began at 30 W with the power output being increased 15 W.min-1 until volitional fatigue. Ear and finger probe pulse oximetry measurements of available hemoglobin (%Spo2) were compared with arterial oxyhemoglobin fraction of total hemoglobin (%HbO2) measured directly from arterial blood samples using a CO-oximeter. To provide a wide range of %HbO2 values, four subjects exercised under hypoxic conditions [inspired partial pressure of O2 (PIo2) = 107 Torr], while the remaining six subjects exercised under normoxic conditions (PIo2 = 150 Torr). Because carboxyhemoglobin (HbCO) or methemoglobin (MetHb) is not measured by pulse oximeters, %HbO2 was corrected for HbCO and MetHb and expressed as percent arterial O2 saturation of available Hb (%Sao2). Small and insignificant differences (P greater than 0.05) existed between SpO2 (all 3 instruments) and %SaO2 at the lowest work rate and the highest power output achieved. Regression analyses of %SpO2 vs. %SaO2 produced correlation coefficients of r = 0.82 [standard error of the estimate [(SEE) = 1.79], r = 0.89 (SEE = 1.48), and r = 0.93 (SEE = 1.14) for the Biox IIa, Ohmeda 3700 (ear), and the Ohmeda 3700 (finger) pulse oximeters, respectively. We conclude that pulse oximetry, within the above limits of accuracy, is useful in estimating %SaO2 during exercise in healthy subjects.     

不同海拔地区(南京和拉萨)种植的甘蓝型油菜的种子基因差异表达

分别在南京(海拔8.9 m)和拉萨(海拔3 658 m)2个不同海拔地区种植甘蓝型油菜(Brassica napus)高油品系H105, 该材料含油量在两地分别为(46.04±1.42)%和(53.09±1.35)%。利用拟南芥表达谱基因芯片检测两地种植的H105开花后30天种子基因的表达。以种植在南京的H105为对照, 差异表达分析结果显示有421个差异表达的基因, 其中229个基因表达下调, 192个基因表达上调。这些基因按功能可初步分为代谢相关、运输相关、结合相关、转录相关、结构相关、发育相关、信号转导相关、其它相关及功能未知基因等几大类别。一些与光合成、糖代谢以及脂肪酸合成相关的重要基因, 如叶绿素a-b结合蛋白基因家族、蔗糖合酶、丙酮酸激酶、6-磷酸葡萄糖酸脱氢酶、ATP-柠檬酸裂解酶、柠檬酸合酶、异柠檬酸脱氢酶、脂肪酸去饱和酶(FAD6和FAD7)基因等被鉴定为差异表达。研究结果初步揭示了相关基因的表达变化规律, 为探讨油菜在不同海拔地区含油量差异的分子遗传机理提供了重要信息。     

Coagulation and fibrinolysis in acute mountain sickness and beginning pulmonary edema

To examine whether intravascular coagulation and/or decreased fibrinolysis precedes high-altitude pulmonary edema (HAPE) we examined 25 male mountaineers (median age 40 yr) at low altitude (550 m) and after 6, 18, and 42 h at an altitude of 4,559 m, which was climbed in 24 h. In 14 subjects, 2 of whom showed radiological evidence of HAPE after 42 h, symptoms of acute mountain sickness (AMS) were mild or absent. Eleven subjects suffered from AMS, six of whom developed radiologically documented HAPE after 18 or 42 h. In the absence of AMS there were no significant changes at high altitude, with the exception of a decrease in bleeding time from 246 +/- 18 to 212 +/- 13 (SE) (P less than 0.05). In AMS, partial thromboplastine time decreased from 34.2 +/- 0.8 to 31.1 +/- 0.5 s (P less than 0.001) and factor VIII procoagulant activity and von Willebrand factor antigen were increased by 57 +/- 12 and 70 +/- 13%, respectively (P less than 0.001), whereas there were no significant changes in beta-thromboglobulin (BTG), fibrinopeptide A (FPA), and fibrin fragment B beta 15-42. In subjects with HAPE, BTG, FPA, and B beta 15-42 were normal before and in beginning HAPE. Preceding HAPE, euglobulin clot lysis time declined at high compared with low altitude from 289 +/- 48 to 201 +/- 42 min without venous occlusion (VO) and from 107 +/- 36 to 86 +/- 31 min after VO (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)     

Reusable sensors in intrapartum foetal reflection pulse oximetry

OBJECTIVES: To evaluate the accuracy of intrapartum foetal pulse oximetry (SO(2POX)) using reusable sensors and the effect of a sensor performance test on data quality. Furthermore, to assess the sensor-related costs by using reusable sensors and sensor performance test. METHODS: 36 reusable sensors were used for SO(2POX) during labour of 289 term foetuses. A sensor performance test device assessing the emitter and receiver capability and the firmness of attachment of the sensors had been developed and used in the last 134 measurements before each resterilisation. Oxygen saturation (SaO(2)) at birth was measured spectrophotometrically after cord blood sampling. The accuracy of SO(2POX) was evaluated by analysing its relationship to SaO(2). The valid SO(2POX) data, as confirmed by subsequent sensor test in the second group, was considered comparable with those with single sensor use. Sensor-related average cost (sensors, test device and sterilisation) of such measurements was compared with that of single sensor use. RESULTS: Eight sensors failed performance test despite valid pulse oximetry signal output during their last measurements. There were significant overall linear correlations between SO(2POX) and SaO(2) (r=0.45, P<0.0001). Separate analyses of regression in the group without sensor performance testing showed an r(2) of 0.41, whereas in the group with subsequent sensor performance testing, the r(2) was 0.52 (P<0.05). By reusing the sensors, the sensor-related cost per valid measurement was $18.9 and 71% lower compared to single use of sensors ($65). CONCLUSIONS: Pulse oximetry may reflect fetal oxygen saturation. Data quality may be compromised by insufficient sensor performance, even though the reflection signal quality is acceptable. If sensor performance is tested before each measurement, reusable sensors may reduce the costs of fetal pulse oximetry.     

Effect of naloxone on gonadotrophin secretion at various stages of development in the ewe lamb

Spring-born crossbred ewe lambs were raised in a natural photoperiod and saline (N = 6) or naloxone (1 mg/kg) in saline (N = 6) was injected (i.m.) every 2 h for 6 h at 5, 10 and 15 weeks of age and for 8 h at 20, 25 and 30 weeks of age. Blood samples were taken every 12 min during treatment periods. Naloxone had no effect on time to first oestrus (controls 235 +/- 6 days, naloxone 242 +/- 7 days). Mean serum LH concentrations and LH pulse frequency were elevated by naloxone in ewe lambs at 20, 25, and 30 weeks of age (P less than 0.05). The only FSH response to naloxone was a depression of mean serum concentrations at 30 weeks of age (P less than 0.05). LH pulse amplitude was elevated at 5 weeks of age in all ewe lambs and declined thereafter to a nadir at 30 weeks of age in control, but not in naloxone-treated animals (P less than 0.05). LH pulse frequency was elevated at 10 weeks of age in control ewe lambs and in all animals at 30 weeks of age (P less than 0.05). FSH pulse frequency declined from 5 weeks of age in control ewe lambs (P less than 0.05), with very few pulses noted in 25- and 30-week-old animals. We conclude that (1) opioidergic suppression of LH, but not FSH, secretion developed at 20 weeks of age in the growing ewe lambs used in the present study, with no obvious change in suppression before the onset of first oestrus: (2) pulsatile FSH secretion occurred in the young ewe lamb but was lost as the lamb matured: (3) attainment of sexual maturity was preceded by an elevation in LH pulse frequency.     

Postoperative residual paralysis and respiratory status: a comparative study of pancuronium and vecuronium

The objective of this prospective double-blind study was to determine whether postoperative residual paralysis (PORP) after pancuronium or vecuronium results in hypoxemia and hypercapnia in the immediate admission period to the recovery ward. Eighty-three consecutive surgical patients received balanced or intravenous anesthesia with pancuronium for operations lasting longer than one hour or vecuronium for those lasting less than 60 min, both combined with neostigmine at the end of anesthesia. Standard clinical criteria assessed neuromuscular function intraoperatively. Postoperatively, we determined neuromuscular function (acceleromyography with supramaximal train-of-four (TOF) stimulation of the ulnar nerve, and a 5-s head lift) and pulmonary function (pulse oximetry: SpO2, and blood gas analysis: SaO2, PaCO2). We defined PORP as a TOF-ratio <70%, hypoxemia as a postoperative SpO2 > or =5% below the pre-anesthestic level together with a postoperative SaO2 <93%, and hypercapnia as a PaCO2 > or =46 mm Hg. Among the 49 pancuronium and 27 vecuronium patients studied, the PORP rates were 20% in the pancuronium group and 7% in the vecuronium group (p>0.05). Hypoxemia and hypercapnia occurred more often in pancuronium patients with PORP than in those without PORP namely 60% vs. 10% (p<0.05) and 30% vs. 8% (p>0.05), respectively. We conclude that PORP after pancuronium is a significant risk factor for hypoxemia.     

唐古拉红景天防治肝纤维化机制研究

目的：探讨唐古拉红景天对肝纤维化的治疗作用,并探讨作用机制。方法：将60只wistar大鼠随机分为正常组、模型组和红景天治疗组。采用CCL4复合造模法造成肝纤维化,同时进行不同药物治疗,6周后采血并处死动物取材做病理学检查。采用免疫组化检测肝组织中Fas、FasL和NF-кB蛋白含量的表达,采用放射免疫法检测血清LN和FN的含量。结果：模型组肝小叶结构紊乱,出现脂肪变性及大量气球样变,中央静脉及汇管区周围胶原纤维组织明显增多。正常组和治疗组肝小叶结构规则。正常组肝组织Fas、FasL蛋白呈棕黄色弱阳性表达,模型组Fas、FasL蛋白较正常组明显增强（P〈0.05）;治疗组Fas、FasL蛋白的表达均较模型组有明显的减弱（P〈0.05）;正常组肝组织NF-κB蛋白呈棕黄色阳性强表达,模型组NF-κB蛋白的表达较正常组明显减弱（P〈0.05）;治疗组NF-κB蛋白的表达较模型组有明显的增强（P〈0.05）;模型组血清Ⅲ型前胶原氨基端肽（PⅢNP）、LN的表达较正常组明显增强（P〈0.05）;治疗组血清PⅢNP、LN的表达均较模型组有明显的减弱（P〈0.05）。结论：唐古拉红景天通过抑制肝细胞的凋亡对肝纤维化具有一定的防治作用。     

Fluctuation in responsiveness of LH and lack of responsiveness of FSH to prolonged infusion of morphine and naloxone in the ewe

In ewes in the mid-luteal phase, LH pulse frequency (P less than 0.01) and amplitude (P less than 0.05) increased during a 24 h infusion of naloxone (0.5 mg/kg/h) compared to a 24 h infusion of vehicle (mean +/- s.e.m.; 0.25 +/- 0.03 vs 0.14 +/- 0.01 pulses/h and 0.84 +/- 0.08 vs 0.55 +/- 0.08 ng/ml serum, respectively). The increase in pulse amplitude was immediate, but was less (P less than 0.05) during the second 12 h, compared to the first 12 h, of naloxone infusion (0.52 +/- 0.14 vs 0.98 +/- 0.08 ng/ml serum). Oestradiol concentrations were higher (P less than 0.01) during naloxone than during control infusion (5.63 +/- 0.26 vs 4.13 +/- 0.15 pg/ml serum). In ovariectomized ewes in the breeding season, LH pulse frequency was lower (P less than 0.01) during a 24 h infusion of morphine (0.5 mg/kg/h) than during a 24 h infusion of vehicle (mean +/- s.e.m.; 1.17 +/- 0.08 vs 1.71 +/- 0.06 pulses/h). We conclude that long-term infusion of naloxone results in a sustained increase in LH pulse frequency but only a transient elevation in pulse amplitude. No effects on FSH secretion were noted. LH secretion was sensitive to morphine in the absence of ovarian steroids, suggesting that ovarian steroids are not required for the presence of functional opioid receptors capable of modulating LH release.     

Autonomic cardiovascular regulation in subjects with acute mountain sickness

The aims of this study were 1) to evaluate whether subjects suffering from acute mountain sickness (AMS) during exposure to high altitude have signs of autonomic dysfunction and 2) to verify whether autonomic variables at low altitude may identify subjects who are prone to develop AMS. Forty-one mountaineers were studied at 4,559-m altitude. AMS was diagnosed using the Lake Louise score, and autonomic cardiovascular function was explored using spectral analysis of R-R interval and blood pressure (BP) variability on 10-min resting recordings. Seventeen subjects (41%) had AMS. Subjects with AMS were older than those without AMS (P < 0.01). At high altitude, the low-frequency (LF) component of systolic BP variability (LF(SBP)) was higher (P = 0.02) and the LF component of R-R variability in normalized units (LF(RR)NU) was lower (P = 0.001) in subjects with AMS. After 3 mo, 21 subjects (43% with AMS) repeated the evaluation at low altitude at rest and in response to a hypoxic gas mixture. LF(RR)NU was similar in the two groups at baseline and during hypoxia at low altitude but increased only in subjects without AMS at high altitude (P < 0.001) and did not change between low and high altitude in subjects with AMS. Conversely, LF(SBP) increased significantly during short-term hypoxia only in subjects with AMS, who also had higher resting BP (P < 0.05) than those without AMS. Autonomic cardiovascular dysfunction accompanies AMS. Marked LF(SBP) response to short-term hypoxia identifies AMS-prone subjects, supporting the potential role of an exaggerated individual chemoreflex vasoconstrictive response to hypoxia in the genesis of AMS.     

The role of oxygen-increased respirator in humans ascending to high altitude

ABSTRACT: BACKGROUND: Acute mountain sickness is common for people who live in low altitude areas ascending to the high altitude. Many instruments have been developed to treat mild cases of AMS. However, long-lasting and portable anti-hypoxia equipment for individual is not yet available. METHODS: Oxygen-increased respirator (OIR) has been designed to reduce the risk of acute mountain sickness in acute exposure to low air pressure. It can increase the density of oxygen by increasing total atmospheric pressure in a mask. Male subjects were screened, and eighty-eight were qualified to perform the experiments. The subjects were divided into 5 groups and were involved in some of the tests at 4 different altitudes (Group 1, 2: 3700 m Group 3,4,5: 4000 m, 4700 m, 5380 m) with and without OIR. These tests include heart rate, saturation of peripheral oxygen (SpO2), malondialdehyde (MDA), superoxide dismutase (SOD), blood lactate (BLA) and PWC (physical work capacity) -170. RESULTS: The results showed that higher SpO2, lower heart rate (except during exercise) and better recovery of heart rate were observed from all the subjects 'with OIR' compared with 'without OIR' (P < 0.05). Moreover, compared with 'without OIR', subjects 'with OIR' in Group 1 had lower concentrations of MDA and BLA, and a higher concentration of SOD (P < 0.05), while subjects 'with OIR' in Group 2 showed better physical capacity (measured by the PWC-170) (P < 0.05). The additonal experiment conducted in a hypobaric chamber (simulating 4,000 m) showed that the partial pressure of oxygen in blood and arterial oxygen saturation were higher 'with OIR' than 'without OIR' (P < 0.05). CONCLUSIONS: We suggested that OIR may play a useful role in protecting people ascending to high altitude before acclimatization.