An uncommon cause of acute right ventricular failure and high mixed venous oxygen saturation

Ruptured sinus of Valsalva aneurysms are rare. We report a case in which the usual clinical manifestations were not present and the patient was initially treated as an acute pulmonary embolus. Despite three negative echocardiograms an intra-cardiac shunt was suspected because of a persistently elevated mixed venous oxygen saturation. Cardiac catheterisation confirmed the diagnosis. Surgical repair was performed and post operative recovery was uneventful.     

Effect of pentoxifylline on veno-occlusive priapism-induced corporeal tissule lipid peroxidation in a rat model

Objective: To investigate whether pentoxifylline could play a role in attenuation of the hazardous effects of ischemia/reperfusion on corporeal tissue in a rat model of veno-occlusive priapism (VOP). Materials and methods: Placebo and pentoxifylline were given to eight groups of rats prior to priapism being induced by a vacuum constrictive device for durations of 6 and 12 h, respectively. Half of the groups of rats that underwent the same duration of priapism (ischemic) were subjected to 1 h of detumescence after band removal (reperfusion). One group underwent no manipulation and no drug administration and served as a baseline determination (control). Corporeal homogenates were examined for lipid peroxidation (LP) derived malondialdehyde (MDA) accumulation via thiobarbituric acid assay. Results: MDA concentration differed significantly between VOP rats and controls (P < 0.001) but did not differ significantly between ischemic-only groups and reperfused groups (P > 0.05). In the pentoxifyllinepretreated groups, although MDA accumulation tended to be slightly lower than in the placebo groups, the difference was not statistically significant (P > 0.05) either in the 6- or 12-h duration priapic groups. Conclusions: LP, an indicator of radical oxygen metabolite (ROM) induced injury, occurs in rat corporeal tissue during and after abolishment of VOP. Single-dose pentoxifylline pretreatment failed to exert a protective effect on corporeal tissue in a rat model of VOP in terms of attenuation of LP.     

Diving physiology and pathophysiology

Summary. Divers have worked at 500 m depth in the sea and have reached 700 m in simulated chamber dives. A prerequisite for this has been extensive physiological studies of the body's reactions to pressure and pressure changes. This paper reviews such physiological and pathophysiological studies with emphasis on recent developments.     

医用氧舱检验与安全

本文介绍了医用氧舱的检验，医用氧舱的检验包括舱体、供排气、氧系统、电气系统等“硬件”设备的检验和设计、安装与使用管理的“软件”方面的检验。同时，针对检验过程中发现的影响医用氧舱安全使用的常见问题，本文进行了详细的讨论。     

Blockade of superoxide generation prevents high-affinity immunoglobulin E receptor-mediated release of allergic mediators by rat mast cell line and human basophils

BACKGROUND: Previous studies have shown that rat peritoneal mast cells and mast cell model rat basophilic leukaemia (RBL-2H3) cells generate intracellular reactive oxygen species (ROS) in response to antigen challenge. However, the physiological significance of the burst of ROS is poorly understood. OBJECTIVE: The present study was undertaken to investigate the role of superoxide anion in mediator release in rat and human cell systems. METHODS: RBL-2H3 cells were directly stimulated with anti-rat FcepsilonRI alpha-subunit monoclonal antibody (mAb). For the analysis of human cell system, leucocytes were isolated by dextran sedimentation from healthy volunteers or from patients, and challenged either with anti-human FcepsilonRI mAb or with the relevant antigens. Superoxide generation was determined by chemiluminescence-based methods. The releases of histamine and leukotrienes (LT)s were determined by enzyme-linked immunosorben assay (ELISA). RESULTS: Cross-linking of FcepsilonRI on RBL-2H3 cells or on human leucocytes from healthy donors by the anti-FcepsilonRI mAb resulted in a rapid generation of superoxide anion, as determined by chemiluminescence using superoxide-specific probes. Similarly, leucocytes from patients generated superoxide anion in response to the challenge with the relevant allergen but not with the irrelevant allergen. Furthermore, diphenyleneiodonium (DPI), a well-known inhibitor of flavoenzymes suppressed the superoxide generation and the release of histamine and LTC4 induced by the anti-FcepsilonRI mAb or by allergen in parallel. CONCLUSION: These results indicate that both RBL-2H3 cells and human basophils generate superoxide anion upon FcepsilonRI cross-linking either by antibody or by allergen challenge and that blockade of the generation prevents the release of allergic mediators. The findings strongly support the role of superoxide generation in the activation of mast cells and basophils under both physiological and pathological conditions. The findings suggest that drugs regulating the superoxide generation have potential therapeutic use for allergic disorders.     

Age-related changes in oxygen saturation over the first year of life: A longitudinal study

Stability of oxygen saturation depends on maturation and function of individual components of the respiratory system. The aim of this study was to record and analyse comprehensive oxygen saturation data in a longitudinal study over the first year of life. Detailed sleep studies were performed on 15 normal infants eight times in the first year of life. The accrued oxygen saturation data were analysed on a computerized oximetry data analysis system. Results show the mean sleep saturation levels trending upwards and stabilizing by 185 days. There was an inverse curvilinear relationship between mean age and median desaturation time and the median number of desaturations at ≥95, ≥92 and ≥90% saturation. The mean cumulative desaturation time ≥90% in the first 4 months was 11.08 min (range 2.5–36.57 min). This study demonstrates monotonic patterns of increasing saturation and decreasing number and time of desaturations ≥95% and ≥90% but a random pattern of desaturations ≥85% occurs across the first 6 months of life. Cumulative desaturation times over the first 4 months of life were high and could be important to the development of maturity of the respiratory system. After 6 months, all indices of saturation and desaturation point to a stable and mature respiratory system.     

A developmental role for ataxia-telangiectasia mutated in protecting the embryo from spontaneous and phenytoin-enhanced embryopathies in culture.

Ataxia-telangiectasia (A-T) is characterized by impaired recognition and repair of DNA damage and increased sensitivity to ionizing radiation (IR), cancer, and neurodegeneration. We previously showed pregnant knockout mice lacking the A-T gene product ataxia-telangiectasia mutated (Atm) are highly susceptible to the embryopathic effects of IR, which damages DNA, possibly via generation of reactive oxygen species (ROS). Here we show that Atm more broadly protects against both spontaneous and phenytoin-enhanced embryopathies. In the absence of drug exposure, cultured embryos from pregnant Atm knockout mice showed more embryopathies than wild-type littermates, with a gene dose-dependent decrease in susceptibility from -/- to +/- to +/+ embryos (p < 0.05). A similar but significantly enhanced gene dose-dependent pattern of embryopathic susceptibility was evident in Atm knockout embryos exposed to the ROS-initiating teratogen phenytoin (p < 0.05). These results provide the first evidence that Atm has a broad developmental importance beyond IR embryopathies, possibly by protecting the embryo from constitutive and xenobiotic-enhanced oxidative stress, with even heterozygotes showing increased risk. This developmental role of Atm further implicates DNA damage in ROS-mediated teratogenesis and DNA damage response and repair as risk factors for individual susceptibility.     

胰腺癌细胞的增殖同膜脂质饱和度,膜胰岛素受体的关系

外源性表皮生长因子(或生长抑素)能促进(或抑制)胰腺癌细胞的增殖。胰腺癌细胞增殖速率的高低与细胞膜脂质饱和度的降、升;与膜胰岛素受体数量的增减密切相关。测定细胞膜脂质饱和度和胰岛素受体数量,是判断胰腺癌增殖状态的灵敏指标,有一定临床价值。     

Pathogenesis of progressive muscular dystrophy: studies on free radical metabolism in an animal model

Evidence to suggest the presence of abnormal metabolism of oxygen free radicals in progressive muscular dystrophy is presented using an animal model. In the superficial pectoral muscles of dystrophic chickens, enzyme activities regulating the metabolism of oxygen free radicals, i.e., catalase, superoxide dismutases and glutathione peroxidase, were significantly elevated within 1 week of hatching. Activities of related enzymes, i.e., glutathione reductase, glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase were also elevated. In contrast, the specific activity of phosphofructokinase, the rate-limiting enzyme of the glycolytic pathway, was normal during the first 4-week period. These results suggest that there is an increased turnover of oxygen free radicals in the dystrophic muscle. This concept appears important in a further investigation of the pathogenesis and treatment of progressive muscular dystrophies.     

缺血－再灌注兔心肌肌浆网自由基的测定

应用电子自旋共振波谱仪（ＥＳＲ）直接检测了缺血－再灌注兔心肌肌浆网自由基的变化，以探讨肌质网系统与氧自由基的关系。实验中将２０只兔随机分为再灌注对照组、超氧化物歧化酶（ＳＯＤ）组、ＡＴＰ－氯化镁组和人参皂甙Ｒｅ组。实验结果，ｇ值２．００４６处为半醌自由基波谱，其相对浓度各组依次为７８．９４±２．１２６，１４．４６±２．８６，２０．６５±７．６５，１４．６６±３．６７（ｘ±ＳＤ），对照组与用药组均有显著性差异（Ｐ＜０．０５），表明缺血－再灌注兔心肌肌浆网产生大量的自由基，用ＥＳＲ可以直接检测到半醌自由基，外源性高能磷酸盐制剂ＡＴＰ－氯化镁及人参皂甙Ｒｅ与超氧化物歧化酶一样，发挥清除兔心肌肌浆网自由基的作用。