高分压氧体外抑制大鼠脾脏淋巴细胞功能及N-乙酰半胱氨酸的预防作用

目的 :观察高分压氧体外暴露对脾淋巴细胞功能的影响及 N-乙酰半胱氨酸 (NAC)的预防作用。 方法 :分离成年大鼠脾脏淋巴细胞 ,制成细胞悬液 ,置于压力舱内以 4 0 0 k Pa氧气 (含 1.5 % CO2 )培养 4 h。 NAC预防组在培养液中加入 30mm ol/ L NAC。用流式细胞术测定淋巴细胞亚型 ,3H- Td R掺入法测定淋巴细胞增殖反应及 EL ISA法测定细胞经刀豆球蛋白(Con A )刺激后分泌的 IL - 2水平。 结果 :经高分压氧处理后 ,脾淋巴细胞 CD3+ 、CD4 + CD3+ 及 CD8+ CD3+ 比例均显著下降(P<0 .0 1,P<0 .0 5 ) ,CD4 + CD3+ / CD8+ CD3+ 比值未有变化 ;淋巴细胞增殖率及经 Con A刺激后的 IL - 2分泌量显著减少(P<0 .0 1,P<0 .0 5 )。培养液中添加 30 mm ol/ L NAC后 ,各指标值的下降程度均明显减轻 (P<0 .0 1,P<0 .0 5 )。 结论 :高分压氧对离体大鼠脾淋巴细胞功能有直接抑制作用 ,NAC能部分预防该抑制作用。     

Cerebral perfusion during human liver transplantation

Summary. During transplantation of the liver cerebral perfusion was monitored by transcranial Doppler determined middle cerebral artery mean flow velocity (V_mean) and pulsatility index (PI) in six fulminant hepatic failure patients and 11 patients with chronic liver disease. In both groups of patients V_mean, PI and central haemodynamic variables were recorded during (1) the last preanhepatic hour; (2) the anhepatic phase; (3) the first 15 min of reperfusion; and (4) for the following 45 min of reperfusion. No significant differences were detected between the two groups of patients with respect to changes of variables with time. The V_mean (40±13 cm s^-1 [mean±SD]), thoracic electrical impedance (TI) (30±7 Ohm), heart rate (97±19 beats min^-1), mean arterial pressure (84±9 mmHg) and arterial carbon dioxide tension (PaCO₂, 4.5±0.4 kPa) remained stable in the anhepatic phase, while cardiac output (CO, 7.6±2.7 to 5.4±1.41 min^-1), stroke volume (SV, 79±26 to 56±15 ml) and PI (1.2±0.3 to 0.9±0.2) decreased (P<0.05). During reperfusion, CO (9.9±4.01 min^-1), SV (105±40 ml), Pa_CO2 (5.5±0.6 kPa), Vmean (57±17 cm s^-1) and PI (1.2±0.2) became elevated. Taken together, during the anhepatic phase of the liver transplantation a maintained central blood volume as indicated by the constant TI served for a stable blood pressure and in turn cerebral perfusion, whereas revascularization of the graft increased cerebral perfusion concomitant with an elevated carbon dioxide tension.     

The accuracy of a fiberoptic oximeter over a wide range of arterial oxygen saturation values in piglets

A piglet model was used to evaluate the accuracy of a fiberoptic oximeter over a wide range of arterial oxygen saturation (SaO₂) values. In eight anaesthetized piglets, the inspired oxygen concentration was varied from 30% to 6% resulting in a SaO₂ range from 100% to 15%. Paired data of the Opticath® fiberoptic catheter, which was placed in the descending aorta, and blood sample SaO₂ values assessed by a multiwavelength oximeter, were analysed. After in vitro calibration according to the manufacturer's instruction, the fiberoptic catheter started to underestimate the SaO₂ below 78%, worsening towards lower SaO₂ values. The overall bias was -3. 4% and the precision 3. 8%. An off-line fit with a non-linear model resulted in a standard deviation of residuals of 2. 6%. After several in vivo calibration adjustments when the Fiberoptic oximeter deviated more than 4% from the blood sample value, the bias was eliminated over the total SaO₂ range and the precision was 3. 7%. The Opticath® fiberoptic oximeter could have an accuracy for the whole SaO₂ range between 15–100% close to the accuracy of the multiwavelength oximeter, when the fiberoptic oximeter is adapted for the underestimation below 78% SaO₂.     

Transcranial cerebral oximetry and carotid cavernous fistula occlusion

Summary Different methods have been used in the evaluation and monitoring of the cerebral oxygen supply during neuro-interventional therapies. Attenuation of near-infrared light by the chromophores oxyhemoglobin and deoxyhemoglobin have shown to be useful in the study of the cellular oxygen metabolism and oxygen delivery to the brain. Transcranial cerebral oximetry (TCCO) has the advantage of providing real-time information regarding regional brain oxygen saturation (rSO₂) by using wavelengths in the near-infrared range.We present a patient with a carotid cavernous fistula who underwent balloon occulusion and concurrent continuous TCCO monitoring. TCCO was found to be a useful tool providing immediate rSO₂ values during the angiographic and interventional procedures. Initial balloon occlusion of a carotid cavernous fistula resulted in partial occlusion of the internal carotid artery lumen causing an immediate decrease in rSO₂ which correlated with angiographic findings. Subsequent reocclusion of the fistula produced a slower and smaller degree of decrease in rSO₂ with clinical improvement in the patient. Changes in rSO₂ were detected before any adverse clinical event was observed. TCCO was reliable, safe, sensitive, and provided a real-time assessment tool for the monitoring of brain oxygen supply in a patient undergoing a neuroendovascular procedure.     

脉冲吸氧与脉冲吸氧仪

本文介绍了脉冲吸氧的机理和优越性以及脉冲吸氧仪的原理。脉冲吸氧可以增加吸氧效果,减少感染,大大降低氧耗量。     

环隙气升式反应器在非牛顿流体体系中的应用──反应器特性研究和体积氧传递系数的关联

以羧甲基纤维素钠（ＣＭＣ）水溶液模拟非牛顿型发酵介质，在内径为０．１５ｍ，高为０．９７５ｍ的环隙气升式反应器内，考察了液体流变性质和导流筒结构对气液传质的影响，提出了体积氧传递系数（ＫＬａ）的经验关联式。实验表明：对于较高粘度的假塑性流体，反应器内部采用整体式导流筒结构，将有利于传质和混合，其性能优于采用开窗式导流筒或无导流筒的反应器。     

Environmental effects on the growth and proteolysis of Treponema denticola ATCC 33520

The effect of pH, redox potential, O₂ and H₂ on the growth and proteolytic activity of Treponema denticola ATCC 33520 was studied in a chemostat at different growth rates. The peptidase and protease activities were estimated using different amido-methyl coumarin derivatives and azocasein. The maximum growth rate of T. denticola ATCC 33520 was 0.14 h⁻¹. Reduction of the growth rate of T. denticola by 50–60% gave: an increase in cell mass of 150–200%, a higher acetogenesis and a shift of the pH optimum. The protease and phenylalanine peptidase activities seemed to be of greater importance for the growth of T. denticola ATCC 33520 than the rather low arginine and proline peptidase activities. The redox potential (E_h) played a secondary role. At microaerophilic conditions with 1–5% O₂, the cultures maintained a redox potential below −311 mV and an optimal acetogenesis. The presence of H? induced a marked growth stimulation of T. denticola ATCC 33520. It is concluded that the cell mass and proteolytic activity of T. denticola ATCC 33520 are modulated by the growth rate and the pH and to a lesser extend by the redox potential and presence of O₂. Stagnation of the exudate-flow influences these factors and will lead to an increase of the spirochetal population and proteolysis in the periodontal pocket.     

Attenuation of myocardial injury due to oxygen free radicals(OFR) by pretreatment with OFR or calcitonin gene-related peptide

目的：研究氧自由基（ＯＦＲ）及降钙素基因相关肽（ＣＧＲＰ）预处置对ＯＦＲ所致离体大鼠心脏损伤的拮抗作用．方法：Ｌａｎｇｅｎｄｏｒｆ法灌流心脏，电解ＫＨ液产生ＯＦＲ．结果：ＣＧＲＰ或ＯＦＲ预处置减轻ＯＦＲ所致心脏收缩功能下降，冠脉流量减少和肌酸激酶（ＣＫ）释放增加．蛋白激酶Ｃ（ＰＫＣ）抑制剂Ｈ７可取消ＯＦＲ预处置的心脏保护作用（对照组，ＯＦＲ损伤组，ＯＦＲ预处置组，Ｈ７加ＯＦＲ预处置组及Ｈ７组的ＣＫ释放量分别是１１０±７，２１５±２３，１６９±１４，２４０±３０，１１３±１９Ｕ·Ｌ－１）．结论：ＯＦＲ或ＣＧＲＰ预处置对ＯＦＲ所致心肌损伤具有拮抗作用，该作用与ＰＫＣ激活有关．     

医院PSA制氧系统购置及配置论证

PSA方式制氧是目前最先进的制氧方式，PSA制氧系统是各医院首选的供氧设备。本文阐述了PSA制氧的工作原理及购置理由，并就如何配置此系统进行了全面地论证。