Randomized,Controlled Trial of Carbon Dioxide Insufflation During Colonoscopy

INTRODUCTION: Insufflation of air is a cause of discomfort during and after colonoscopy. Although this can be minimized by good technique, the use of carbon dioxide insufflation may provide further benefits. Carbon dioxide is rapidly absorbed and excreted through the lungs. We hypothesized that carbon dioxide would alleviate postcolonoscopy discomfort. METHODS: After they had provided informed consent, patients presenting for colonoscopy were randomized into two groups: those in whom air was used for colonoscopy and those in whom carbon dioxide was used. Pain during and ten minutes after colonoscopy was measured on a ten-point analog scale. Data are mean and 95 percent confidence limits. RESULTS: There were 124 patients in the air group and 123 in the carbon dioxide group. Age, body mass index, indication, diagnosis, and number of procedures were similar for the two groups. There were no differences between the groups in the amounts of sedation or analgesia used, the percentage of examinations that were complete (air, 98.4 percent; carbon dioxide, 95.2 percent), or patient satisfaction (on a scale of 1 to 10: air, 9.4; carbon dioxide, 9.5). Although there were more females in the carbon dioxide group (69 vs. 51), hysterectomy rates were the same. Pain scores (mean ± 95 percent confidence interval; scale of 1 to 10) immediately after the examination were 4.3 ± 0.3 for air and 3.6 ± 0.3 for carbon dioxide (no significant difference). Pain scores 10 minutes later were 2.1 ± 0.2 for air and 0.9 ± 0.2 for carbon dioxide (P < 0.05, Students t-test). CONCLUSION: Because there was significantly less abdominal pain ten minutes after colonoscopy in the group in whom carbon dioxide was used, carbon dioxide should be considered as an insufflating gas for colonoscopy.     

Compatibility of Different Commercial Alloys in High-Temperature,Supercritical Carbon Dioxide

In this work, the compatibility and long-term integrity of candidate structural materials, including the austenitic stainless steel 316NG, the Fe-Ni-based alloy 800H, and the Ni-based alloy 625, were tested in high-temperature and high-pressure SCO₂. The exposure time was up to 3000 h. The results showed that the corrosion kinetics approximately followed a near-cubic law for 316NG and 800H. After 3000 h exposure, all oxide layers, mainly composed of Cr₂O₃, were continuous, compact, and protective, and their thicknesses were about 21~45 nm, 64~88 nm, and 34~43 nm, respectively. In the case of carburization, dark spots corresponding carbon deposition were observed on the surface and a little enriched in the underside of the oxide for 800H. Moreover, the enrichment of trace elements was found at the oxide/substrate interface through GDOES and TEM analyses, i.e., the enrichment of Mn and Si for 316NG, the enrichment of Mn, Si, Al, and Ti for 800H, and the enrichment of Ti and Al for alloy 625.     

CO2 pneumoperitoneum does not enhance tumor growth and metastasis: study of a rat cecal wall inoculation model

INTRODUCTION: Although many studies have evaluated the effects of carbon dioxide pneumoperitoneum on port site recurrence, little is known about its outcome on tumor growth and metastasis. The effect of pneumoperitoneum with carbon dioxide on cecal tumor growth and metastasis was compared with laparotomy using a rat colon cancer cell line. METHODS: Time Course Study: Fifty WF/BN F₁ hybrid rats were inoculated with 2,000,000 WB2054M₅ tumor cells into the cecal wall and explored two to ten weeks after injection. Main Study: 152 rats were randomly assigned either to 6-mmHg CO₂ pneumoperitoneum (30 minutes) or 4-cm laparotomy (30 minutes) two weeks after tumor inoculation and were explored four weeks after treatment. RESULTS: Time Course Study: Thirty-seven (95 percent) of the surviving rats developed a cecal wall tumor, and there was progressive tumor growth and metastasis over the ten-week period. At six weeks, metastasis occurred to the liver in 25 percent, to the lung in 38 percent, and to the lymph node in 63 percent, and peritoneal seeding occurred in 38 percent; this time period was chosen for the main study. Main Study: At the time of treatment (2 weeks), 124 rats were eligible for randomization. One hundred two rats survived the six-week period (50 pneumoperitoneum, 52 laparotomy) and were killed. There were no differences between the CO₂ pneumoperitoneum and laparotomy groups regarding cecal tumor growth (1.043vs. 0.894 g) and metastases to the liver (32vs. 37 percent), lung (34vs. 17 percent), lymph node (84vs. 77 percent), and wound or port (20vs. 23 percent). CONCLUSIONS: A cecal wall inoculation model mimics the natural cascade of colon cancer growth and metastasis. CO₂ pneumoperitoneum did not affect the tumor growth and metastasis to the liver and other organs when compared with laparotomy in this model.Read at the meeting of The American Society of Colon and Rectal Surgeons, Boston, Massachusetts, June 24 to 29, 2000, and recipient, Chicago Society of Colon & Rectal Surgeons Award.     

Elevated Carbon Dioxide Tension as a Predictor of Subsequent Adverse Events in Infants with Bronchopulmonary Dysplasia

Infants with bronchopulmonary dysplasia (BPD) are at risk for numerous complications following discharge from the Neonatal Intensive Care Unit (NICU). Few studies have evaluated risk factors for adverse events (AE). This retrospective study provided an initial evaluation of the use of capillary carbon dioxide (PCO2) tension as a predictor of infants with BPD at increased risk for AE. PCO2 was compared in patients who suffered, or avoided, severe AE, defined as pulmonary hypertension, death, or subsequent reintubation or tracheostomy for respiratory illness. One hundred twelve consecutive patients followed at the BPD clinic were evaluated, and data from 104 subjects were suitable for analysis. Mean PCO2, obtained shortly before or after discharge from NICU, was 47.2 mmHg (range, 31–83). PCO2 was significantly higher in patients who required reintubation and ventilation (54.7 vs. 46.7, p < 0.04). No cutoff value of PCO2 clearly distinguished patients with subsequent AE. PCO2 was not significantly higher in the group of patients who had a severe AE than in the group of patients who did not have a severe AE, but logistic regression showed a significant association between PCO2 and risk of both severe AE (p = 0.018), and readmission to hospital (p = 0.038). An elevated PCO2 is associated with an increased risk of AE, including reintubation, and readmission to hospital, in infants with BPD. Patients with an elevated discharge PCO2 may require closer monitoring during followup. Prospective studies will be needed to confirm these observations. The work was funded by the Ontario Thoracic Society.     

Inhibitory effects of carbon dioxide insufflation on pneumoperitoneum and bowel distension after percutaneous endoscopic gastrostomy

AIM: To evaluate the inhibitory effects of carbon dioxide (CO₂) insufflation on pneumoperitoneum and bowel distension after percutaneous endoscopic gastrostomy (PEG).METHODS: A total of 73 consecutive patients who were undergoing PEG were enrolled in our study. After eliminating 13 patients who fitted our exclusion criteria, 60 patients were randomly assigned to either CO₂ (30 patients) or air insufflation (30 patients) groups. PEG was performed by pull-through technique after three-point fixation of the gastric wall to the abdominal wall using a gastropexy device. Arterial blood gas analysis was performed immediately before and after the procedure. Abdominal X-ray was performed at 10 min and at 24 h after PEG to assess the extent of bowel distension. Abdominal computed tomography was performed at 24 h after the procedure to detect the presence of pneumoperitoneum. The outcomes of PEG for 7 d post-procedure were also investigated.RESULTS: Among 30 patients each for the air and the CO₂ groups, PEG could not be conducted in 2 patients of the CO₂ group, thus they were excluded. Analyses of the remaining 58 patients showed that the patients’ backgrounds were not significantly different between the two groups. The elevation values of arterial partial pressure of CO₂ in the air group and the CO₂ group were 2.67 mmHg and 3.32 mmHg, respectively (P = 0.408). The evaluation of bowel distension on abdominal X ray revealed a significant decrease of small bowel distension in the CO₂ group compared to the air group (P < 0.001) at 10 min and 24 h after PEG, whereas there was no significant difference in large bowel distension between the two groups. Pneumoperitoneum was observed only in the air group but not in the CO₂ group (P = 0.003). There were no obvious differences in the laboratory data and clinical outcomes after PEG between the two groups.CONCLUSION: There was no adverse event associated with CO₂ insufflation. CO₂ insufflation is considered to be safer and more comfortable for PEG patients because of the lower incidence of pneumoperitoneum and less distension of the small bowel.     

Functional Materials Based on Active Carbon and Titanium Dioxide in Fog Seal

Due to its ability to degrade nitrogen oxides under ultraviolet, titanium dioxide has been applied in asphalt concrete to degrade automobile exhaust in recent years. To highlight the protection of road traffic environmental quality and mitigate automobile exhaust on human health, this study proposes combining titanium dioxide and active carbon into Sand-fog seal to form a pavement coating material with a photocatalytic function. It uses active carbon to reinforce the material’s function, and the coupling agent for modification makes it well dispersed in the Sand-fog seal. The indoor experiments were carried out at 30 °C and relative humidity of 30%. It tested the composite material’s degradation efficiency on nitrogen dioxide in relation to component proportions, coupling agents, and dosages. The study concluded that the optimal photocatalytic efficiency could be achieved when the ratio of active carbon to titanium dioxide is 0.6. After being modified by the titanate coupling agent and through Scanning Electron Microscope tests, it can be seen that materials can be well dispersed into the Sand-fog seal. When the composite material accounts for 10% of the fog seal, it can achieve the optimal photocatalytic efficiency of about 23.9%. The British pendulum tests show it has good skid resistance performance. Half a kilometer of concrete roadway was sprayed with the material coating in Tianjin, China. The photocatalytic experimental road degrades nitrogen oxides better than the original road. The method is feasible for practical implementation.     

不同时期使用胰岛素治疗妊娠心脏病并糖尿病的效果

目的探究妊娠心脏病并糖尿病患者不同时期使用胰岛素治疗的临床效果。方法2017年7月-2019年7月,甄选在该院接受诊断治疗的妊娠心脏病并糖尿病患者共100例展开研究,随机均匀分为对照组(n=50,孕32周后采用胰岛素治疗)和观察组(n=50,孕32周前采用胰岛素治疗),对照比较疗效和妊娠结局。结果与对照组比较,观察组的治疗总有效率显著较高,差异有统计学意义(P<0.05);不良妊娠结局发生率观察组均低于对照组(P<0.05)。结论在孕32周前采用胰岛素治疗妊娠心脏病并糖尿病的效果显著,降低了不良妊娠结局发生率,值得推广应用。     

Effect of Oxide Coating on Performance of Copper-Zinc Oxide-Based Catalyst for Methanol Synthesis via Hydrogenation of Carbon Dioxide

The effect of oxide coating on the activity of a copper-zinc oxide–based catalyst for methanol synthesis via the hydrogenation of carbon dioxide was investigated. A commercial catalyst was coated with various oxides by a sol-gel method. The influence of the types of promoters used in the sol-gel reaction was investigated. Temperature-programmed reduction-thermogravimetric analysis revealed that the reduction peak assigned to the copper species in the oxide-coated catalysts prepared using ammonia shifts to lower temperatures than that of the pristine catalyst; in contrast, the reduction peak shifts to higher temperatures for the catalysts prepared using L(+)-arginine. These observations indicated that the copper species were weakly bonded with the oxide and were easily reduced by using ammonia. The catalysts prepared using ammonia show higher CO₂ conversion than the catalysts prepared using L(+)-arginine. Among the catalysts prepared using ammonia, the silica-coated catalyst displayed a high activity at high temperatures, while the zirconia-coated catalyst and titania-coated catalyst had high activity at low temperatures. At high temperature the conversion over the silica-coated catalyst does not significantly change with reaction temperature, while the conversion over the zirconia-coated catalyst and titania-coated catalyst decreases with reaction time. From the results of FTIR, the durability depends on hydrophilicity of the oxides.     

培哚普利对自发性高血压大鼠内源性一氧化碳的影响

目的探讨培哚普利对自发性高血压大鼠(SHR)内源性一氧化碳(CO)产生的影响。方法选取自发性高血压大鼠(SHR)及年龄、体质量相匹配的正常血压(WKY)大鼠各16只,随机各分为培哚普利组和对照组(各8只),胃内分别注入培哚普利2mg/(kg.d)或等量生理盐水14d,于试验开始前一天和结束当天分别采血,应用连二亚硫酸钠将血液中的多组分血红蛋白还原为血红蛋白(Hb)和碳氧血红蛋白(COHb),用双波长分光光度法测定全血420nm和432nm的吸光度,计算出COHb的百分含量,并用放射免疫技术检测血浆中血管紧张素Ⅱ(AngⅡ)的水平。结果培哚普利治疗后,WKY大鼠血压、AngⅡ及COHb百分含量无变化;但SHR血压及血浆AngⅡ含量明显降低[SHR组收缩压:培哚普利组:(153.5±10.1)比对照组:(170.6±11.4)mmHg,P<0.01;SHR组AngⅡ:培哚普利组:(427.7±31.7)比对照组:(529.7±40.5)pg/mL,P<0.01],培哚普利还明显升高COHb百分含量[SHR组COHb:培哚普利组:(1.40±0.14)%比对照组:(1.28±0.10)%,P=0.01]。SHR培哚普利组用药后较用药前血压和AngⅡ明显降低(P<0.05),而COHb百分含量明显升高[(1.40±0.14比1.29±0.16)%,P=0.001],实验结束时SHR培哚普利组和对照组COHb含量与AngⅡ浓度均呈负相关(r分别为-0.54和-0.49,P<0.05)。结论培哚普利可能通过抑制AngⅡ的生成,使内源性CO的产生增加。     

Effects of Ethanol and Carbon Tetrachloride upon Vitamin A Status of Rats

The effects of ethanol and carbon tetrachloride (CCl4) upon tissue vitamin A, liver lipids, liver cytochrome P450 and hepatic morphology were investigated. It was anticipated that CCl4 treatment would have more severe effects upon vitamin A status because CCl4 provides greater hepatic injury than does ethanol. After a 2-week standardization feeding period, young male rats were divided into four groups. For 5 weeks one group of rats (n = 17) received ethanol in liquid diets (30% of calories) while another (n = 8) was exposed to CCl4 inhalation twice a week along with phenobarbital in the diet. All groups received the National Regulatory Commission recommended level for vitamin A. Comparison of ethanol and its pair-fed control group (n = 17) revealed: decreased hepatic vitamin A, no change in serum vitamin A, increased percentage of liver lipid, and cytochrome P450 with moderate fat accumulation in hepatocytes. Comparison of the CCl4-phenobarbital group with pair-fed controls (n = 8) showed: increased serum vitamin A, decreased hepatic vitamin A, increased cytochrome P450, marked hepatic fat accumulation, hepatic cell necrosis, and early cirrhosis. Thus, CCl4 (with phenobarbitol), which is a more potent hepatotoxin as evidenced by a more elevated cytochrome P450 and distorted liver morphology, not only reduced liver vitamin A, but also increased serum vitamin A. The extent of substrate and/or organ specificity remains to be elucidated.     

二氧化碳灌注提高老年患者结肠镜检查舒适度的随机对照研究

背景：常规空气灌注式结肠镜检查往往会造成不同程度的腹痛、腹胀等不适,探求更好的结肠镜检查方式具有重要临床意义。目的：评价二氧化碳（CO2）灌注用于老年患者结肠镜检查的舒适度和安全性。方法：98例老年患者随机分为4组,各组基线情况基本一致,分别以空气或CO2为注气媒介,辅以或不辅以镇痛药行结肠镜检查。以直观模拟量表（VAS）评价检查中和检查后5、10、15、20min腹痛、腹胀情况。每组分别随机选取8例患者,8例于检查后10min行动脉血气分析,另8例于检查后60min拍摄腹部X线平片评价肠管扩张程度。结果：CO2组和CO2＋镇痛组各时点腹痛、腹胀VAS评分以及检查后肠管扩张程度评分分别显著低于空气组和空气＋镇痛组（P〈0．01）,CO2＋镇痛组检查中腹痛、腹胀VAS评分显著低于CO2组（P〈0．05）。四组间各项结肠镜操作参数以及动脉血pH值和PCO2差异无统计学意义,且均无严重并发症发生。结论：CO2灌注式结肠镜检查用于老年患者安全、有效,舒适度较空气灌注式结肠镜检查明显提高。     

Macroscopic and Microscopic Properties of Cement Paste with Carbon Dioxide Curing

Carbon dioxide is the main component of greenhouse gases, which are responsible for an increase in global temperature. The utilization of carbon dioxide in cement-based materials is an effective way to capture this gas. In this paper, the influence of carbon dioxide curing on the setting time, the electrical resistivity, dry shrinkage ratio, water absorption by unit area and mechanical strengths (flexural and compressive strengths) were determined. The scanning electron microscope, X-ray diffraction and thermogravimetric analysis were obtained to investigate the mechanism of carbonation reaction of cement paste. Water–cement ratios of cement paste were selected to be 0.3, 0.4 and 0.5. Results showed that carbon dioxide curing could accelerate the setting of cement paste. The electrical resistivity decreased with the increasing water–cement ratio and increased with the carbon dioxide curing. Moreover, the evaluation function for the curing age and dry shrinkage rate or the mechanical strengths fit well with the positive correlation quadratic function. The water absorption by unit area increased linearly with the testing time. The carbon dioxide curing led to increasing the mechanical strengths and the dry shrinkage ratio. Meanwhile, the carbon dioxide curing demonstrated a decreasing effect on the water absorption by unit area. The mechanical strengths were improved by the carbon dioxide curing and increased in the form of quadratic function with the curing age. As obtained from the microscopic findings, that the carbon dioxide curing could accelerate the reaction of cement and improve the compactness of cement paste.     

不同缺血预处理对心肌细胞的影响

目的：明确缺血预处理的刺激量与其心肌细胞保护效果的关系。方法：以Ｗｉｓｔａｒ大鼠为模型，开胸安置缺血再灌注装置。将４８只大鼠分为４组，每组各１２只：Ａ组持续阻断冠状动脉１小时，再灌注２小时；Ｂ组缺血５分钟，再灌注５分钟，阻断冠状动脉１小时，再灌注２小时；Ｃ组缺血５分钟，再灌注５分钟，重复３次，阻断冠状动脉１小时，再灌注２小时；Ｄ组缺血１０分钟，再灌注５分钟，阻断冠状动脉１小时，再灌注２小时。检测血浆肌酸激酶浓度与心脏切片氯化硝基四氮唑蓝染色，判断心肌梗死范围；磁带记录心电，分析心律失常。结果：缺血预处理对缺血心肌有明显的保护作用；增加刺激量（缺血预处理的时间与次数），没有增加保护效果。结论：心肌细胞的缺血预处理保护可能依靠阈值触发，无论刺激强弱，一旦启动则是充分完全地发挥保护作用。而超过阈值的强刺激可能有害无益     

Electrochemical Investigation of the Corrosion of Different Microstructural Phases of X65 Pipeline Steel under Saturated Carbon Dioxide Conditions

The aim of this research was to investigate the influence of metallurgy on the corrosion behaviour of separate weld zone (WZ) and parent plate (PP) regions of X65 pipeline steel in a solution of deionised water saturated with CO₂, at two different temperatures (55 °C and 80 °C) and at initial pH~4.0. In addition, a non-electrochemical immersion experiment was also performed at 80 °C in CO₂, on a sample portion of X65 pipeline containing part of a weld section, together with adjacent heat affected zones (HAZ) and parent material. Electrochemical impedance spectroscopy (EIS) was used to evaluate the corrosion behaviour of the separate weld and parent plate samples. This study seeks to understand the significance of the different microstructures within the different zones of the welded X65 pipe in CO₂ environments on corrosion performance; with particular attention given to the formation of surface scales; and their composition/significance. The results obtained from grazing incidence X-ray diffraction (GIXRD) measurements suggest that, post immersion, the parent plate substrate is scale free, with only features arising from ferrite (α-Fe) and cementite (Fe₃C) apparent. In contrast, at 80 °C, GIXRD from the weld zone substrate, and weld zone/heat affected zone of the non-electrochemical sample indicates the presence of siderite (FeCO₃) and chukanovite (Fe₂CO₃(OH)₂) phases. Scanning Electron Microscopy (SEM) on this surface confirmed the presence of characteristic discrete cube-shaped crystallites of siderite together with plate-like clusters of chukanovite.     

Carbon dioxide-angiography for patients with peripheral arterial disease at risk of contrast-induced nephropathy

Patients with peripheral arterial disease(PAD) and critical limb ischemia are at risk for limb amputation and require urgent management to restore blood flow.Patients with PAD often have several comorbidities, including chronic kidney disease, diabetes mellitus, and hypertension. Diagnostic and interventional angiography using iodinated contrast agents provides excellent image resolution but can be associated with contrast-induced nephropathy(CIN). The use of carbon dioxide(CO_2) as a contrast agent reduces the volume of iodine contrast required for angiography and reduces the incidence of CIN. However, CO_2 angiography has been underutilized due to concerns regarding safety and image quality. Modern CO_2 delivery systems with advanced digital subtraction angiography techniques and hybrid angiography have improved imaging accuracy and reduced the incidence of CIN. Awareness of the need for optimal imaging conditions, contraindications, and potential complications have improved the safety of CO_2 angiography. This review aims to highlight current technological advances in the delivery of CO_2 in vascular angiography for patients with PAD and critical limb ischemia, which result in limb preservation while preventing kidney damage.     

冠心病不同阶段血清的差异蛋白质组学研究

目的通过比较冠心病4个不同阶段的血清蛋白质表达的差异,寻找与冠心病的发生发展相关的特异蛋白质。方法采用蛋白质组学双向凝胶电泳联合质谱的技术方法对正常健康人、冠心病中高危人群、冠心病急性期患者及冠心病稳定期患者蛋白质组学比较研究。结果通过鉴定得到了7种差异蛋白质:视黄醇结合蛋白4(RBP4)、载脂蛋白E(ApoE)、载脂蛋白A1(ApoA1)、CD5抗原样蛋白(CD5L)、结合珠蛋白(Hp)、血清白蛋白(ALB)、簇连蛋白(CLU)。结论这些与冠心病相关的差异蛋白质主要通过参与脂质代谢、炎症反应以及氧化损伤等过程而导致动脉粥样硬化的发生。     

High Capacity Nanocomposite Layers Based on Nanoparticles of Carbon Materials and Ruthenium Dioxide for Potassium Sensitive Electrode

This work presents the new concept of designing ion-selective electrodes based on the use of new composite materials consisting of carbon nanomaterials and ruthenium dioxide. Using two different materials varying in microstructure and properties, we could obtain one material for the mediation layer that adopted features coming of both components. Ruthenium dioxide characterized by high electrical capacity and mixed electronic-ionic transduction and nano-metric carbon materials were reportedly proved to improve the properties of ion-selective electrodes. Initially, only the materials and then the final electrodes were tested in the scope of the presented work, using scanning and transmission electron microscope, contact angle microscope, and various electrochemical techniques, including electrochemical impedance spectroscopy and chronopotentiometry. The obtained results confirmed beneficial influence of the designed nanocomposites on the ion-selective electrodes’ properties. Nanosized structure, high capacity (characterized by the electrical capacitance value from approximately 5.5 mF for GR + RuO₂ and CB + RuO₂, up to 14 mF for NT + RuO₂) and low hydrophilicity (represented by the contact angle from 60° for GR+RuO₂, 80° for CB+RuO₂, and up to 100° for NT + RuO₂) of the mediation layer materials, allowed us to obtain water layer-free potassium-selective electrodes, characterized by rapid and stable potentiometric response in a wide range of concentrations-from 10⁻¹ to 10⁻⁶ M K⁺.     

Effect of Carbon Dioxide on Pulmonary Vascular Tone at Various Pulmonary Arterial Pressure Levels Induced by Endothelin-1

There have been contradictory reports suggesting that CO₂ may constrict, dilate, or have no effect on pulmonary vessels. Permissive hypercapnia has become a widely adopted ventilatory technique used to avoid ventilator-induced lung injury, particularly in patients with acute respiratory distress syndrome (ARDS). On the other hand, respiratory alkalosis produced by mechanically induced hyperventilation is the mainstay of treatment for newborn infants with persistent pulmonary hypertension. It is important to clarify the vasomotor effect of CO₂ on pulmonary circulation in order to better evaluate the strategies of mechanical ventilation in intensive care. In the present study, pulmonary vascular responses to CO₂ were observed in isolated rat lungs (n = 32) under different levels of pulmonary arterial pressure (PAP) induced by various doses of endothelin-1 (ET-1). The purposes of this study were to investigate (1) the vasodilatory effect of 5% CO₂ in either N₂ (hypoxic-hypercapnia) or air (normoxic-hypercapnia) at different PAP levels induced by various doses of endothelin-1, and (2) the role of nitric oxide (NO) in mediating the pulmonary vascular response to hypercapnia, hypoxia, and ET-1. The results indicated that (1) CO₂ produces pulmonary vasodilatation at high PAP under ET-1 and hypoxic vasoconstriction; (2) the vasodilatory effect of CO₂ at different pressure levels varies in accordance with the levels of PAP, the dilatory effect tends to be more evident at higher PAP; and (3) endogenous NO attenuates ET-1 and hypoxic pulmonary vasoconstriction but does not augment the CO₂-induced vasodilatation.     

一氧化碳吸入对大鼠供体肺组织细胞凋亡的影响

目的观察吸入低浓度一氧化碳（CO）对大鼠供体肺组织细胞凋亡的影响。方法建立大鼠肺移植离体肺灌注试验模型，SD大鼠24只，按照有无CO吸入分为空白对照组、CO吸入组，每组均取6对分别作为肺移植的供体鼠和受体鼠。再灌注后一小时切取供体肺组织，在光镜和电镜下比较肺组织细胞学改变，用末端脱氧核苷酸转移酶介导的dUTP缺口末端标记（TUNEL）法比较肺组织细胞凋亡的变化。结果CO吸人组肺组织细胞损伤较对照组明显减轻，凋亡细胞数量明显减少。结论吸入一氧化碳可以明显抑制大鼠供体肺组织细胞的凋亡，减轻供体肺移植术后的缺血再灌注损伤。