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141.
目的:探讨高压氧治疗重度颅脑损伤的疗效。方法:重度颅脑损伤患者35例为治疗组,20例为对照组,观察高压的氧治疗前后临床、脑电地形图的变化及预后。结果:治疗组临床(GCS)、脑电地形图及预后经高压氧治疗后均明显改善,而对照组改善不明显。结论:高压氧能够明显改善重度颅脑损伤患者的临床,脑电地形图及预后。 相似文献
142.
Bavo Vanden Eynde Dirk Vienne Magda Vuylsteke-Wauters Dirk Van Gerven 《European journal of applied physiology》1988,57(4):430-434
Summary To determine the cardiorespiratory response to maximal exercise before, during and after the pubescent growth spurt, thirty boys were tested at yearly intervals over a period of six consecutive years. For each individual, peak height velocity (PHV) was determined. The age at PHV (¯X= 13.6 years) was taken as a standard of maturation. The results from all subjects at 1.5 and 0.5 years before and 0.5 and 1.5 years after PHV are presented. The highest oxygen uptake (
) obtained during an incremental bicycle ergometer test to voluntary exhaustion was taken as peak oxygen uptake (
peak). Across each of the four years studied, mean
peak (min=49.6; max=52.5 ml·kg–1·min–1) and mean heart rate (HR) at
peak (min=190; max=192) did not change significantly as a function of PHV. On the other hand, the respiratory quotient at
peak increased considerably from mean minima and maxima of 0.99 and 1.01 before PHV to 1.07 and 1.10 after PHV. Ventilatory equivalent for
(
), taken as an indicator of ventilatory economy, seemed to be unaffected by the maturation process. The steepest increase in circumpubertal oxygen pulse was found one year after PHV. Average stability coefficients (¯r), calculated from the inter-years correlations were high for height (¯r=0.95), weight (¯r=0.92), HR at
peak (¯r=0.74),
peak in 1/min (¯r=0.71), oxygen pulse (¯r=0.68) and tidal volume (¯r=0.64). 相似文献
143.
Hyperbaric oxygenation mitigates focal cerebral injury and reduces striatal dopamine release in a rat model of transient middle cerebral artery occlusion 总被引:16,自引:0,他引:16
Yang ZJ Camporesi C Yang X Wang J Bosco G Lok J Gorji R Schelper RL Camporesi EM 《European journal of applied physiology》2002,87(2):101-107
The usefulness of the administration of hyperbaric oxygen (HBO) in the treatment of acute focal cerebral ischemia remains
debatable. A significant association exists between focal cerebral injury and an excessive release of extracellular dopamine
(DA). In vivo microdialysis was used in the present study to examine the effect of HBO on DA release in the striatum during
ischemia and reperfusion in rats. The histological changes occurring were also evaluated. Focal cerebral ischemia was induced
by occlusion of the middle cerebral artery (MCA) using a surgically placed intraluminal filament. Control rats (n=8) were subjected to 1 h of ischemia, whilst the study rats (n=8) were in addition treated with HBO (2.8 atmospheres of absolute pressure 100% O2) during ischemia. Both groups were returned to breathing room air at normal pressure during reperfusion. Microdialysis samples
were continuously collected at 15 min intervals at 2 μl·min–1. The [mean (SE)] increase in release of striatal DA attained significance after 30 min of occlusion of MCA [170 (24)%], and
continued to increase [268 (26)% at 45 min] reaching a peak level at 60 min [672 (59)%] before returning to the baseline level
during the late reperfusion phase. There was no significant change in the level of DA in HBO treated rats during the period
of ischemia. A significant reduction in edema and neuronal shrinkage were observed by histological examination in HBO treated
rats when compared to the control rats. The results showed that HBO, when administered during ischemia, offered significant
neuroprotection in our experimental model of transient focal cerebral ischemia in the rat. The mechanism seems to imply, at
least in part, a reduced level of DA.
Electronic Publication 相似文献
144.
Regulation of sperm function by reactive oxygen species 总被引:9,自引:0,他引:9
Ford WC 《Human reproduction update》2004,10(5):387-399
Sperm capacitation can be increased by the addition of reactive oxygen species (ROS) and decreased by antioxidants. Broadly consistent results have been achieved with a wide variety of methods and across different species. Exposure to ROS increases protein tyrosine phosphorylation consequent on an increase in cAMP and activation of tyrosine kinase and inhibition of tyrosine phosphatase. The measurement of ROS production by sperm is complicated by contamination of suspensions by leukocytes, laying many studies open to doubt. In human sperm the observation that extracellular NADPH could support superoxide production detected with the chemiluminescent probe lucigenin and had physiological effects similar to hydrogen peroxide led to the suggestion that they contained NADPH oxidase activity to generate ROS to support capacitation. However, the realization that lucigenin can signal superoxide artefactually, combined with failure to detect superoxide production using spin trapping techniques or to detect NADPH oxidase components in mature sperm, and confirmation of old reports that NADPH solution contains substantial amounts of hydrogen peroxide due to autoxidation, have undermined this hypothesis. Although the presence of significant NADPH oxidase activity in mature human sperm now seems less likely, other observations continue to suggest that they can make ROS in some way. There is stronger evidence that animal sperm can make ROS although these may be mainly of mitochondrial origin. 相似文献
145.
目的:研究SeO2对急性早幼粒细胞白血病细胞株NB4、红白血病细胞K562、急性粒细胞白血病细胞株HL-60的增生、凋亡、活性氧(ROS)及Ca2+水平等的影响。 方法: 采用不同浓度SeO2(3-30 μmol/L)分别处理3种白血病细胞,用流式细胞术测定细胞凋亡率、细胞中ROS和Ca2+的水平。 结果: 10和30 μmol/L SeO2能抑制3种细胞增生,30 μmol/L SeO2作用48 h能使54.0%的NB4细胞、46.5%的K562细胞和49.6%的HL-60细胞发生凋亡。同时下调细胞内ROS和Ca2+水平。NB4和HL-60细胞中ROS阳性细胞比例随SeO2浓度增加而减少,K562中只有30 μmol/L SeO2才能使ROS出现明显下降。10、30 μmol/L SeO2能使NB4和HL-60细胞内Ca2+水平逐步下降。K562中只有30 μmol/L SeO2才能使细胞内Ca2+水平出现明显下降。 结论: SeO2对3种白血病细胞均有诱导凋亡作用,在凋亡过程中涉及细胞内ROS及Ca2+水平下降。 相似文献
146.
Varicocele: effect on sperm functions 总被引:2,自引:0,他引:2
Despite the numerous studies published over the past decade, the role of varicocele in male infertility is still controversial. Although more frequent in infertile men, its influence on sperm production or function has not, as yet, been determined. Moreover, the exact mechanism of varicocele action is not clear. We have surveyed the literature, the correlation of varicocele to sperm parameters and to sperm function tests, such as binding capacity, hypo-osmotic swelling test, presence of reactive oxygen species, and in particular, the correlation to fertility potential. Almost every subject examined had contradictory results. Larger control studies may possibly elucidate and clarify the cases in which varicocele is associated to sperm function, and where treatment may improve fertility. 相似文献
147.
Tom Klausen Troels Dirch Poulsen Niels Fogh-Andersen Jean-Paul Richalet Ove Juel Nielsen Niels Vidiendal Olsen 《European journal of applied physiology》1996,72(4):297-302
This study tested the hypothesis that the diurnal variations of serum-erythropoietin concentration (serum-EPO) observed in normoxia also exist in hypoxia. The study also attempted to investigate the regulation of EPO production during sustained hypoxia. Nine subjects were investigated at sea level and during 4 days at an altitude of 4350 m. Median sea level serum-EPO concentration was 6 (range 6–13) U·l–1. Serum-EPO concentration increased after 18 and 42 h at altitude, [58 (range 39–240) and 54 (range 36–340) U·l–1, respectively], and then decreased after 64 and 88 h at altitude [34 (range 18–290) and 31 (range 17–104) U·l–1, respectively]. These changes of serum-EPO concentration were correlated to the changes in arterial blood oxygen saturation (r = –0.60,P = 0.0009), pH (r = 0.67,P = 0.003), and in-vivo venous blood oxygen half saturation tension (r = –0.68,P = 0.004) but not to the changes in 2, 3 diphosphoglycerate. After 64 h at altitude, six of the nine subjects had down-regulated their serum-EPO concentrations so that median values were three times above those at sea level. These six subjects had significant diurnal variations of serum-EPO concentration at sea level; the nadir occurred between 0800–1600 hours [6 (range 4–13) U·l–1], and peak concentrations occurred at 0400 hours [9 (range 8–14) U·l–1,P = 0.02]. After 64 h at altitude, the subjects had significant diurnal variations of serum-EPO concentration; the nadir occurred at 1600 hours [20 (range 16–26) U·l–1], and peak concentrations occurred at 0400 hours [31 (range 20–38) U·l–1,P = 0.02]. This study demonstrated diurnal variations of serum-EPO concentration in normoxia and hypoxia, with comparable time courses of median values. The results also suggested that EPO production at altitude is influenced by changes in pH and haemoglobin oxygen affinity. 相似文献
148.
Bedaiwy MA Goldberg JM Falcone T Singh M Nelson D Azab H Wang X Sharma R 《Human reproduction (Oxford, England)》2002,17(3):601-604
BACKGROUND: Oxidative stress mechanisms are involved in the pathophysiology of many reproductive disorders. The objective of this study was to characterize oxidative stress parameters in hydrosalpingeal fluid (HSF) and examine their possible role in early embryo development. METHODS AND RESULTS: HSF was aspirated at laparoscopic salpingectomy in 11 infertile women. Reactive oxygen species (ROS), total (non-enzymatic) antioxidant capacity (TAC) and lipid peroxidation (LPO) were assayed. Two-cell mouse embryos were incubated with 25, 50 or 75% HSF and the blastocyst development rate was observed. ROS was detected in five of 11 (45%) HSF samples with a mean of 4.2 x 10(4) c.p.m. LPO was detected in all samples at a mean (+/- SD) value of 5575.4 +/- 6091.9 micromol/l malonaldehyde. The mean blastocyst development rate at 25, 5+/- 0 and 75% HSF and in the control group was 88.9 +/- 9.4, 65.7 +/- 19.1, 45.7 +/- 5.7 and 96.7% respectively (P < 0.0001). The blastocyst development rate was positively correlated to ROS concentrations (P < 0.02) but was not significantly related to LPO. CONCLUSIONS: The blastocyst development rate decreased with increasing concentrations of HSF. For the first time, the presence of ROS, LPO and TAC activity in human HSF was characterized. A possible role of oxidative stress in the embryotoxicity of HSF is suggested. 相似文献
149.
The concept of the accumulated O2 deficit (AOD) assumes that the O2 deficit increases monotonically with increasing work rate (WR), to plateau at the maximum AOD, and is based on linear extrapolation of the relationship between measured steady-state oxygen uptake (O2) and WR for moderate exercise. However, for high WRs, the measured O2 increases above that expected from such linear extrapolation, reflecting the superimposition of a "slow component" on the fundamental O2 mono-exponential kinetics. We were therefore interested in determining the effect of the O2 slow component on the computed AOD. Ten subjects [31 (12) years] performed square-wave cycle ergometry of moderate (40%, 60%, 80% and 90%
), heavy (40%), very heavy (80%) and severe (110% O2 peak) intensities for 10–15 min, where
is the estimated lactate threshold and is the WR difference between
and O2 peak. O2 was determined breath-by-breath. Projected "steady-state" O2 values were determined from sub-
tests. The measured O2 exceeded the projected value after ~3 min for both heavy and very heavy intensity exercise. This led to the AOD actually becoming negative. Thus, for heavy exercise, while the AOD was positive [0.63 (0.41) l] at 5 min, it was negative by 10 min [–0.61 (1.05) l], and more so by 15 min [–1.70 (1.64) l]. For the very heavy WRs, the AOD was [0.42 (0.67) l] by 5 min and reached –2.68 (2.09) l at exhaustion. For severe exercise, however, the AOD at exhaustion was positive in each case: +1.69 (0.39) l. We therefore conclude that the assumptions underlying the computation of the AOD are invalid for heavy and very heavy cycle ergometry (at least). Physiological inferences, such as the "anaerobic work capacity", are therefore prone to misinterpretation. 相似文献
150.
目的: 新生鼠的神经生发区-室管膜下区(SVZ) 和海马齿状回(DG)聚集了多种不同发育阶段神经干细胞(NSCs),它们可分化产生新的神经元和胶质细胞。本研究探讨缺氧缺血性脑损伤(HIBD)对脑生发区NSCs的损伤及高压氧(HBO)对此损伤的影响。从在体NSCs 探讨HBO对新生大鼠HIBD的保护作用机制。 方法: 新生7 d龄SD大鼠随机分为4组:① 正常对照组(CON,n=16);② HIBD 模型组(HIBD,n=16);③ 高压空气组(HBA,n=16);④HBO治疗组(n=16)。Rice法复制HIBD模型,并予HBA或HBO治疗,每天1次共7 d。BrdU免疫组化显示在体NSCs。并取损伤侧脑SVZ区组织,体外NSCs培养并进行神经干细胞球计数。 结果: HIBD组生发区在体BrdU 阳性细胞和体外培养的神经干细胞球数目明显少于对照组。HBO组SVZ区的BrdU阳性细胞增多;体外培养的神经干细胞球增多。HBA组增加不明显。 结论: 新生大鼠HIBD后生发区NSCs减少,HBO治疗可以减轻HIBD后NSCs的死亡。HBA治疗无明显作用。 相似文献