Adaptive changes in cerebral blood flow and oxygen consumption during ethanol intoxication in the rat

Cerebral blood flow (CBF) and oxygen consumption (CMRO₂) were measured during acute and long-term ethanol intoxication in the rat. The purpose was to investigate whether the adaptive changes (development of tolerance) occurring in the CNS during ethanol intoxication were associated with changes in CBF and/or CMRO₂. Consistent with other studies we found that acute severe ethanol intoxication (median blood alcohol concentration (BAC=5.4 mg/ml)) caused a significant decrease in CBF and CMRO₂. After 3–4 days of severe intoxication (BAC of 6.6 mg/ml) these physiological variables were less affected indicating that functional tolerance had developed: CMRO₂ and CBF during acute ethanol intoxication were 9.3 ml/100 g/min and 60 ml/100 g/min respectively; after the long term intoxication period these variables reached 11.2 ml/100 g/min and 78 ml/100 g/min respectively, i.e. values not significantly lower than those of the control group. After induction of hypercapnia (PaCO₂ about 80 mmHg) CBF increased by 360% in the control group; in the acutely intoxicated group CBF increased by only 127% and in the long term intoxicated group by 203 % indicating that the cerebrovascular CO₂-reactivity had also adapted to the ethanol intoxication. It is concluded that adaptive changes of the CNS to chronic ethanol intoxication comprise alterations in CMRO₂, CBF and cerebrovascular reactivity.     

活性氧对红细胞膜流动性影响的研究

目的 :研究活性氧诱导红细胞发生氧化溶血的机制。方法 :用不同浓度的 H2 O2 作用于离体正常红细胞 ,分别用比色法、硫代巴比妥酸荧光法、荧光偏振法测定红细胞溶血度、红细胞膜脂质过氧化物 (L PO)、红细胞膜微粘度。结果 :5 0 ,10 0 ,12 0 mm ol/ L 浓度的 H2 O2 作用于红细胞后 ,均引起红细胞发生氧化溶血 ,红细胞溶血度、红细胞膜 L PO、红细胞膜微粘度均明显增加 ;H2 O2 在 5 0～ 12 0 mm ol· L- 1浓度范围内 ,红细胞溶血度、红细胞膜 L PO、红细胞膜微粘度的增加与 H2 O2 有明显的量效关系 ;红细胞膜微粘度与红细胞溶血度呈明显正相关 ,红细胞膜 L PO与红细胞膜微粘度呈明显正关。结论 :活性氧引发红细胞膜脂质过氧化导致红细胞膜流动性降低在活性氧诱导红细胞发生氧化溶血的机制中起一定的作用     

常压氧治疗胎儿-胎盘循环功能降低疗效的多普勒超声心动图观察

目的评价常压氧在胎儿-胎盘循环功能降低治疗中的疗效.方法应用超声心动图观察52例胎儿胎盘循环功能降低在常压氧治疗前后的变化情况并与45例普通吸氧组及41例未治疗组进行对照.结果52例胎盘循环功能降低胎儿中43倒常压氧治疗后胎盘循环功能恢复正常,有效率82.7%.明显高于对照组(P＜0.01).结论常压氧是治疗胎儿胎盘循环功能降低安全、有效的方法.     

腺苷脱氨酶抑制剂对氧反常大鼠心脏的保护作用

本文观察到腺苷脱氨酶抑制剂EHNA对离体灌流大鼠心脏氧反常性损伤有明显的作用,此外还发现在缺氧期(无氧灌流30分钟)EHNA也表现出明显的保护作用,心脏收缩幅度的降低和静息张力的升高均显著低于对照组。表明在缺氧期也可能有自由基的产生。     

Methods for in vivo haematoporphyrin derivative quantification: a review

Photodynamic therapy is a new treatment for early carcinomas. Although undergoing phase 1/2 clinical assays, clinical indications for this therapy remain rare mainly because of the approximate dosimetry of HPD uptake by tumour tissues in human beings.In this review we present the potential interest and limits of both direct fluorescence detection or dosimetry of HPD and in vivo measurements of singlet oxygen, produced during photodynamic therapy. Clinical applications of such measurements should represent one of the main conditions for the future development of photodynamic therapy.

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Résumé La photochimiothérapie est un nouveau traitement des cancers débutants. Alors que des essais cliniques de phase 1–2 sont entrepris, les indications pour ce type de traitement demeurent rares, principalement du fait d'une dosimétrie approximative de la captation de l'hématoporphyrine dérivée par les tissus cancéreux humains. La fluorescence émise par l'HPD peut Être utilisée in-vivo pour un diagnostique topographique de la répartition de l'HPD, mais aussi le dosage quantitatif des espèces fluorescentes présentes dans le mélange HPD. Le dosage de l'oxygène singulet, généré lors de la réaction photochimique, est nettement plus difficile à réaliser mais a été proposé pour le dosage in-vivo des formes porphyriniques actives présentes dans le milieu. Les applications cliniques de telles mesures représentent une condition essentielle pour le developpement de la photochimiothérapie car à côté des possibilités de diagnotiques offertes par l'analyse de la répartition intratumorale de l'HPD, un dosage précis permettrait d'optimiser le moment du traitement, arbitrairement fixé aujourd'hui à 72 heures.

     

A clinical comparison of indices of pulmonary gas exchange with changes in the inspired oxygen concentration

Several indices have been introduced as convenient alternatives to calculation of the physiological shunt fraction (Qs/QT) for the assessment of pulmonary gas exchange. These include: the arterial-alveolar oxygen tension ratio (a/APO2), the arterial oxygen tension-inspired oxygen concentration ratio (PaO2/FIO2), the respiratory index (RI), [A-a)DO2/PaO2) and the alveolar-arterial oxygen tension difference [A-a)Do2). These indices are in use clinically despite the fact that they may not accurately predict gas exchange in situations where FIO2, Qs/QT or arterial-venous oxygen content is changing. The clinical stability of each of these indices, relative to the behaviour of the physiological shunt, was therefore investigated prospectively in ten mechanically ventilated postoperative adults as FIO2 was varied from 0.30 to 1.00. None of the indices studied reliably reflected the behaviour of the physiological shunt. As FIO2 was increased incrementally from 0.30 to 1.00, 42 to 55 per cent of the measured changes in these indices were opposite in direction to the corresponding changes in the physiological shunt. The maximum magnitudes of the opposite changes were substantial; 24 and 22 per cent for the a/APO2 and PaO2/FIO2 ratio respectively, 67 per cent for the RI and 101 per cent for the (A-a)DO2. We conclude that the use of any of these indices for clinical assessment of a patient's gas exchange defect when FIO2 is varying can be substantially misleading.     

NADPH氧化酶家族在心血管疾病中作用的研究进展

烟酰胺腺嘌呤二核苷酸磷酸氧化酶是心血管系统中活性氧(reactive oxygen species,ROS)的主要来源,它包 括7种亚型并分别表达在不同的心血管细胞及其细胞器中,参与调节细胞增殖、迁移、分化、凋亡、衰老和炎症反应 等多种活动,其衍生的ROS参与高血压、动脉粥样硬化、糖尿病血管病变、心肌梗死后心室重构等多种心血管疾病 的病理过程。