CHX抗栓注射液对小鼠脑缺氧保护作用研究

目的通过CHX抗栓注射液对小鼠断头存活时间和常压耐缺氧能力的影响,观察该药对小鼠脑组织急性缺氧的保护作用.方法给小鼠腹腔注射CHX抗栓注射液每天2.5 nmg/kg,5 mg/kg,7.5 mg/kg,连续7d,实验采用小白鼠断头法和小鼠常压缺氧模型.结果不同浓度的CHX抗栓注射液,均可明显延长小白鼠断头存活时间和常压缺氧存活时间,与对照组相比,差异非常显著.结论 CHX抗栓注射对小白鼠脑缺氧具有保护作用.     

Nitric oxide synthase reduces nitrite to NO under anoxia

Cultured bEND.3 endothelial cells show a marked increase in NO production when subjected to anoxia, even though the normal arginine pathway of NO formation is blocked due to absence of oxygen. The rate of anoxic NO production exceeds basal unstimulated NO synthesis in normoxic cells. The anoxic release of NO is mediated by endothelial nitric oxide synthase (eNOS), can be abolished by inhibitors of NOS and is accompanied by consumption of intracellular nitrite. The anoxic NO release is unaffected by the xanthine oxidase inhibitor oxypurinol. The phenomenon is attributed to anoxic reduction of intracellular nitrite by eNOS, and its magnitude and duration suggests that the nitrite reductase activity of eNOS is relevant for fast NO delivery in hypoxic vascular tissues. Received 20 August 2006; received after revision 21 September 2006; accepted 8 November 2006     

The Siberian Traps and the End-Permian mass extinction: a critical review

The association between the Siberian Traps, the largest continental flood basalt province, and the largest-known mass extinction event at the end of the Permian period, has been strengthened by recently-published high-precision ⁴⁰Ar/³⁹Ar dates from widespread localities across the Siberian province^[1]. We argue that the impact of the volcanism was amplified by the prevailing late Permian environmental conditions―in particular, the hothouse climate, with sluggish oceanic circulation, that was leading to widespread oceanic anoxia. Volcanism released large masses of sulphate aerosols and carbon dioxide, the former triggering short-duration volcanic winters, the latter leading to long-term warming. Whilst the mass of CO₂ released from individual eruptions was small compared with the total mass of carbon in the atmosphere-ocean system, the long ‘mean lifetime’ of atmospheric CO₂, compared with the eruption flux and duration, meant that significant accumulation could occur over periods of 105 years. Compromise of the carbon sequestration systems (by curtailment of photosynthesis, destruction of biomass, and warming and acidification of the oceans) probably led to rapid atmospheric CO₂ build-up, warming, and shallow-water anoxia, leading ultimately to mass extinction.     

宁夏枸杞子对小白鼠运动能力影响的初步研究

本文采用一次灌胃和长期喂养的方法观察了小白鼠服用宁夏枸杞子后其游泳时间、常压耐缺氧存活时间、体重、血红蛋白、（Ｈｂ）的变化以及定量负荷运动后的血糖和血乳酸水平。结果显示小白鼠一次服用７５ｍｇ／１０ｇ的宁夏枸杞子可明显地延长游泳时间（Ｐ＜０．０１）和常压耐缺氧存活时间（Ｐ＜０．０５）。长期喂养实验结果表明连续１０天服用５０ｍｇ／１０ｇ／ｄ的宁夏枸杞子后小鼠的体重、Ｈｂ以及定量负荷运动后的血糖和血乳酸水平均无明显变化（Ｐ＞０．０５）。本文结果初步提示宁夏枸杞子具有抗疲劳、提高运动能力和耐缺氧能力的作用。     

Adenine nucleotide metabolism during anoxia and postanoxic recovery in insects

Severe hypoxia (anoxia), if maintained for more than a few minutes, causes irreversible damage in humans and other mammals. Why mammals are so vulnerable to anoxia is not fully understood. It is therefore of interest to study animals that are more tolerant of anoxia in order to identify physiological and metabolic properties that are correlated with a high tolerance of anoxia. Insects have high metabolic rates and their energy metabolism is dependent on aerobic ATP production. In insects, as in mammals, anoxia causes a rapid breakdown of physiological function, resulting in a state similar to rigor mortis. This is accompanied by a precipitous decrease in metabolic rate. In contrast to mammals, however, insects can survive anoxia for many hours and recover spontaneously and completely when air is again available. We have followed the metabolism of adenine nucleotides in locust tissues (mainly in the flight muscle) over 3 h of anoxia and during recovery from 1 h of anoxia. The content of ATP in the flight muscle dropped to 1% of normal during 2 h of anoxia. The main product was AMP which increased in content more than 20-fold. Some of the AMP was deaminated to IMP and this was further dephosphorylated to inosine. Altogether less than 30% of the total adenine nucleotides were degraded during 3 h of anoxia and this may contribute to the amazing ability of insects to recover from prolonged anoxia.     

Geochemical significance of the relative enrichment of pristane and the negative excursion of δ^13CPr across the Permian-Triassic Boundary at Meishan, China

Changes in the distribution of isoprenoid hydrocarbons and in δ^13Ckero or δ^13Cpr across the section from the Changxing Formation to the lower Yinkeng Formation at Meishan （the GSSP of PTB） are studied, in which a relative enrichment of pristane and a sharp shift in both δ^13Ckero and δ^13Cmole near the boundary are revealed. A possible mechanism for the abnormal accumulation of pristane near PTB is suggested： Lipids in some marine animals and their metabolites, rich in pristane, can be preserved and accumulate in some suitable depositing facies under certain special conditions, such as the catastrophic death of animals and/or developing of an anoxic water column, and thus the pristane enrichment occurs in the sediment. The occurrences of isoprenoid enrichment and high Pr/Ph ratios have been found in other typical marine anoxic sediments accompanied by mass extinction in various extent during the most important geological periods, such as Late Ordovician, end of Devonian, Early Jurassic and Late Cretaceous. These occurrences support to a certain extent the above mechanism that interprets the genesis of a high Pr/Ph ratio in some typical marine anoxic sediments. The synchronous sharp negative shifts in δ^13Cmole, δ^13Ckero and δ^13Ccarb from Beds 24 to 26 of the Meishan profile indicate that a sudden and strong variation of carbon source in the atmosphere-ocean system occurred during the quick but equable evolution from the end-Permian to Early Triassic, and the coupling between the pristane enrichment and negative shift in δ^13Ckero and δ^13CPr may well indicate the importance of the release of methane hydrates and marine anoxia in the end-Permian mass extinction.     

妊娠肝内胆汁淤积症30例临床分析

目的 :探讨妊娠肝内胆汁淤积症 (ICP)胎儿宫内缺氧的指标。方法 :对30例ICP患者多项临床及实验室指标进行观察 ,并将其与围产儿结局进行分析。结果:有无瘙痒与围产儿结局差异无显著性 (P>0.05)。血清胆红素升高与否、临产后胎心宫缩监护异常与否、与围产儿结局差异有显著性意义 (P<0.05)。结论 :血清胆红素升高、临产后胎心监护异常可作为预测ICP胎儿宫内缺氧的指标。     

生物接触氧化法处理食品废水运行效果研究

采用缺氧/二级生物接触氧化法(A/BCO)处理食品废水,弥补当前工艺的缺陷,实现投资低、效果稳、污泥少、氨氮和CODcr高去除率.通过对废水中两个主要的指标CODcr和氨氮(NH3-N)的去除率进行水力停留时间(HRT)和气水比(GWR)研究.结果表明,随着HRT的延长,CODcr的去除率呈现较快的增长,之后速度放缓,并且开始呈下降的趋势.同时在此过程中,氨氮的去除率呈现不断上升的趋势,而去除率的增长速度呈不断下降的趋势,最终可以得到结论,最佳水力停留时间为10 h;对GWR而言,随着GWR的不断提高,CODcr去除率是先上升后下降,氨氮的去除率是先升高后平稳再略有下降,最终得到结论,GWR选择为15∶1为佳.     

Rare earth elements and carbon isotope geochemistry of the Doushantuo Formation in South China: Implication for middle Ediacaran shallow marine redox conditions

The middle Ediacaran Shuram excursion, the largest negative δ 13 C carb excursion in Earth history, has been interpreted as indirect evidence for episodic oxidation and remineralization of deep ocean DOC (dissolved organic carbon). It has been hypothesized that such oxidation event may have occurred when anoxic DOC-laden deep water was brought to shallow shelves during oceanic upwelling, which is expected to cause localized anoxia in shallow environments. To test this prediction, we systematically analyzed rare earth elements (REE) and δ 13 C carb of the upper Doushantuo Formation carbonates in the Yangtze Gorges area of South China, which were deposited in an inner shelf environment and record a large negative δ 13 C carb excursion correlated to the Shuram event. The REE data show a significant positive shift in Ce/Ce* values, synchronous with a pronounced negative δ 13 C carb shift. This positive Ce/Ce* shift is interpreted to represent an oceanic anoxia event in shallow shelf environments, which may have been caused by the upwelling or impingement of oxygen-depleted and 12 C-enriched deep water onto shelves. This anoxia event coincides with a sharp decline in the abundance and diversity of Ediacaran acanthomorphic acritarchs, raising the possibility that these two geobiological events may be causally related.