低氧对肌腱细胞基因表达谱的影响

目的 探讨低氧对肌腱细胞基因表达谱的影响.方法 酶消化法分离得到的肌腱细胞分别在低氧（2％O2）和常规氧浓度（21％O2）下进行培养,第1代肌腱细胞进行表达谱检测,并用RT-PCR对其中4个差异表达基因进行验证.结果 低氧培养组与常规氧浓度组相比,有40个基因表达差异,且全部在低氧组表达上调.选取的4个差异表达基因的RT-PCR的验证结果与芯片结果一致.结论 低氧促进肌腱细胞增殖涉及多个基因参与.     

Oxygen tension-associated changes on secondary immune response in halothane or isoflurane anesthetized mice

The impact that reexposure to anesthetics delivered in 100% oxygen or in synthetic air (21% oxygen/79% nitrogen) has on the secondary humoral immune response to sheep red blood cells was studied. Mice were immunized twice with a 15-day interval and anesthetized immediately after each antigenic challenge with 1.5% halothane or 1.5% isoflurane for 40 min. Halothane in oxygen resulted in increased numbers of IgG-secreting cells (IgG-SC), while halothane in air depressed the response when compared to control mice. In contrast, isoflurane vaporized in oxygen did not affect IgG-SC numbers, while isoflurane given in air lowered the response. Furthermore, neither 100% oxygen, nor the stress of being in an anesthesia chamber breathing synthetic air for 40 min had any immunological effect in non-anesthetized mice.
The inspired oxygen concentration during halothane or isoflurane anesthesia has an effect on the secondary immune response. The effect is different between halothane and isoflurane, possibly due to differences in the extent of their metabolic and pharmacodynamic properties.     

Effects of isoflurane on myocardial metabolism during postischaemic reperfusion in the rat

In experiments on isolated rat heart lung preparation, the effects of isoflurane on myocardial metabolism during postischaemic reperfusion were evaluated with intramyocardial high energy phosphates, lactate and glycogen. Hearts were perfused for 10 min initially and made globally ischaemic for 8 min in ischaemic groups. Afterwards, they were reperfused for 12 min. Isoflurane was administered from 5 min after the start of perfusion to the end of reperfusion. There was no significant difference in myocardial lactate levels between ischaemic isoflurane and control groups. However, the ATP level in the hearts in the ischaemic isoflurane group was significantly higher than that in the ischaemic control group (17.96 +/- 1.31 vs 15.50 +/- 0.87; P less than 0.005). The administration of isoflurane to the isolated rat heart during pre- and post-ischaemia enhanced metabolic recovery in the postischaemic state.     

Effects of sevoflurane, isoflurane, enflurane, and halothane on left ventricular diastolic performance in dogs

The effects of volatile anesthetics on active (ventricular relaxation) and passive (chamber stiffness) indices of diastolic function and on left ventricular filling rates in dogs were studied to determine how these agents affect left ventricular diastolic performance. Thirty-five mongrel dogs were randomly assigned to receive sevoflurane, isoflurane, enflurane, or halothane. Left ventricular pressure waveforms, phonocardiograms, and echocardiograms were recorded after administering the anesthetics at concentrations of 0% (control), 1%, 2%, and 3%. Ventricular relaxation was defined as the time constant of the decline in left ventricular pressure. Chamber stiffness was derived from the ventricular pressure-volume relationship during passive filling. Rapid filling rate, slow filling rate, and atrial filling rate were obtained from echocardiograms and phonocardiograms. No change in the time constant or in chamber stiffness was observed at any concentration of sevoflurane or isoflurane. However, the highest studied concentration of enflurane and halothane produced a significant increase in the time constant and in chamber stiffness. Rapid filling rate as well as atrial filling rate decreased significantly with the volatile anesthetics, especially with enflurane and halothane. Sevoflurane and isoflurane did not alter ventricular relaxation or chamber stiffness, but did affect diastolic function as manifested by their alteration of filling rates. In contrast, enflurane and halothane each prolonged ventricular relaxation and increased chamber stiffness. With the administration of the volatile anesthetics, the rapid filling rate decreased with the deterioration of diastolic function; in addition, atrial filling rates decreased and did not compensate for the reduction in early ventricular filling.     

Effects of remifentanil/propofol in comparison with isoflurane on dynamic cerebrovascular autoregulation in humans

BACKGROUND: This study investigates the effects of remifentanil and propofol in comparison to isoflurane on dynamic cerebrovascular autoregulation in humans. METHODS: In 16 awake patients dynamic cerebrovascular autoregulation was measured using transcranial Doppler sonography (TCD). Thereafter patients were intubated, ventilated with O2/air (FiO2=0.33) and randomly assigned to one of the following anesthetic protocols: group 1 (n=8): 0.5 microg x kg(-1) x min(-1) remifentanil combined with a propofol-target plasma concentration of 1.5 microg x ml(-1) group 2 (n=8): 1.8 % isoflurane (1.5 MAC). Following 20 min of equilibration the autoregulatory challenge was repeated. Arterial blood gases and body temperature were maintained constant over time. Statistics: Mann-Whitney U-test and Wilcoxon signed-rank test. RESULTS: Dynamic autoregulation was intact in all patients prior to induction of anesthesia expressed by an autoregulatory index (ARI) of 5.4+/-1.21 (mean+/-SD, group 1) and 5.9+/-0.98 (mean+/-SD, group 2). With remifentanil/propofol anesthesia dynamic autoregulation was similar to the awake state (group 1: ARI=4.9+/-0.88). In contrast, autoregulatory response was delayed with 1.5 MAC isoflurane (group 2, ARI=2.1+/-0.92) (P<0.05). CONCLUSION: These data show that dynamic cerebrovascular autoregulation is maintained with remifentanil-based total intravenous anesthesia. This is consistent with the view that narcotics (and hypnotics) do not alter the physiologic cerebrovascular responses to changes in MAP. In contrast, 1.5 MAC isoflurane delays cerebrovascular autoregulation compared to the awake state.     

Effect of isoflurane on monocyte adhesion molecule expression in human whole blood

BACKGROUND: Recruitment of monocytes to inflamed tissue is a crucial step in the acute inflammatory reaction. Adherence of monocytes to endothelial cells followed by transmigration depends on monocyte surface adhesion molecules, inflammatory cytokines and chemoattractant chemokines. In the present study, we determined the effect of isoflurane on monocyte adhesion receptor expression in vitro. METHODS: Citrated whole blood was incubated for 60 min with either 0.5 or 1 MAC isoflurane. In unstimulated blood samples and after stimulation with N-formyl-methionyl-leucyl-phenylalanine (FMLP) monocyte cell-surface expression of the selectins PSGL-1 and L-selectin, and the beta2-integrins CD11a and CD11b were evaluated by flow cytometry. RESULTS: Isoflurane reduced significantly the expression of PSGL-1 on unstimulated monocytes, whereas the remaining selectins and beta2-integrins were not affected. At both concentrations, the FMLP-induced removal of PSGL-1 from the monocyte surface was increased. Furthermore, at 1 MAC isoflurane the FMLP-induced increase in CD11a expression was significantly inhibited. The surface expression of L-selectin and CD11b was not affected following exposure to isoflurane. CONCLUSION: Isoflurane increases the removal of the selectin PSGL-1 from the monocyte surface. Since PSGL-1 is important during the initial step of monocyte adhesion to endothelial P-selectin, the decrease in monocyte surface PSGL-1 may have profound effects on monocyte-endothelial interactions. Furthermore, the effects of isoflurane on monocyte adhesion molecule expression are different from those reported for neutrophils.     

糖尿病肾病疾病进展相关基因的基因组学研究

目的 研究与糖尿病肾病(DN)进展相关的肾小球基因表达谱及其可能的致病机制。 方法 将DN患者根据蛋白尿、肾小球组织病理学改变和Scr水平分为不同的临床表型组。5例正常对照来自供肾。留取少许肾活检组织，显微镜下分离肾小球，RNA体外线性扩增。采用Affymetrix基因芯片建立DN患者肾小球基因表达谱，以生物信息学方法分析。用实时PCR技术验证基因芯片结果。 结果 不同临床表型的DN患者表现出不同的肾小球基因表达谱。整合3组不同临床表型基因表达谱中共有的变化规律，筛选出与DN疾病进展相关的139个基因。其中表达改变涉及最多的是与糖、脂质代谢相关的基因，其表达水平呈现一致性的下调；表达改变最为显著的是与炎症相关的分子。 结论 大量蛋白尿、肾小球节段硬化和Scr升高等与DN疾病进展相关的临床表型伴有肾小球基因表达谱的改变。在DN进展中，糖代谢和脂质代谢同时发生紊乱，相关基因表达水平一致下调。细胞能量代谢紊乱及继发的局部炎症反应也发挥了重要作用。     

Effects of isoflurane on nitric oxide metabolism and oxidant status of guinea pig myocardium

BACKGROUND: Volatile anesthetics (VAs) have been shown to enhance myocardial recovery during reperfusion, the mechanism of which has not been clarified yet. It has been supposed that this effect of VAs may appear through antioxidative mechanisms. METHODS: Thirty guinea pigs were used in the study. There were three groups with 10 animals in each: I - control, II - isoflurane+oxygen and III - oxygen. Isoflurane (2.0% v/v) and oxygen (100%) mixture was given to the animals via a face mask in the isoflurane+oxygen group at the rate of 21 per min for 30 min a day for three consecutive days. In the oxygen group, oxygen alone (100%) was given under the same conditions as in the isoflurane+oxygen group. At the end of the experiments, the animals were killed and their hearts were removed. In the heart tissues, nitric oxide synthase (NOS) activity, nitric oxide (NO) pool (NO*+NO2-) and malondialdehyde (MDA) levels were measured. RESULTS: NOS activity was found to be higher and the NO pool lower in the isoflurane+oxygen group compared with those of control and oxygen groups. In the oxygen group, MDA level was found to be higher compared to the other groups. There was, however, no significant difference between MDA levels of the control and isoflurane+oxygen groups. CONCLUSION: Our results suggest that isoflurane prevents peroxidation reactions in heart tissue, possibly by scavenging toxic oxygen radicals produced under hyperoxygenation conditions as occurs with general anesthesia.     

Effects of deliberate hypotension induced by labetalol with isoflurane on neuropsychological function

The effect of deliberate hypotension on brain function measured by neuropsychological tests was studied in 41 adult patients. Twenty-four patients were anaesthetized for middle-ear surgery with deliberate hypotension induced by labetalol with isoflurane (hypotensive group). Seventeen patients without hypotension served as a control group. The mean arterial pressure was 77 ± 2 mmHg (10.3 ± 0.3 kPa) before hypotension and 50 ± 0 mmHg (6.7 ± 0.0 kPa) during hypotension in the hypotensive group, and 86 ± 2 mmHg (11.5 ± 0.3 kPa) during anaesthesia in the control group. The following psychological tests were performed: four subtests of the Wechsler Adult Intelligence Scale (similarities, digit span, vocabulary and digit symbol), Trail-Making tests A and B, Zung tests (self-rating anxiety scale and self-rating depression scale) and two-part memory test battery with immediate and delayed recall. The tests were performed preoperatively and 2 days postoperatively. There were no statistically significant differences between the groups in any of the tests in the changes from preoperative value to postoperative value. The results indicate that hypotension induced by labetalol with isoflurane has no significant harmful effects on mental functions compared to normotensive anaesthesia.     

Impact of aging on gene expression in a rat model of ischemic cutaneous wound healing

BACKGROUND: Tissue ischemia and aging are independent features associated with the healing impairment of cutaneous wounds. However, the pathophysiology of these processes as they relate to impaired-healing wounds is poorly understood. MATERIALS AND METHODS: A single full-thickness biopsy wound was made on both ears of young (3-6 month) and aged (>24 month) Fisher rats. One ear was rendered ischemic by transection of the vasculature at the ear base, while the other ear served as an internal nonischemic control. Wounds were harvested from 3 to 7 days and were evaluated histologically for either granulation tissue formation and epithelialization. Total RNA from wounds harvested at postoperative day 7 was probed using a nylon-based cDNA array to assess global genetic expression alterations. RESULTS: Healing in the rat ear model is impaired by both ischemia and advanced age as measured by granulation tissue formation and wound epithelialization. Granulation tissue formation was affected to a greater degree by ischemia than age (-58% versus -21%, respectively) while epithelialization displayed an opposite response (-17% versus -53%, respectively). Global analysis of gene expression suggests that ischemia engenders a marked increase in genes displaying altered expression in aged animals compared to young animals. Importantly, all possible alterations in gene expression are found in samples from aged ischemic wounds, indicating that gene regulation is not simply depressed by advanced age. CONCLUSIONS: Wound epithelialization appears to be affected to a greater degree by advanced age than by ischemia. The results demonstrate the distinctive phenotype presented by the clinically relevant combination of age and ischemia in an in vivo model of cutaneous wound healing.     

Effects of isoflurane on feline intestinal blood flow during hemorrhage-induced hypovolemia

The influence of isoflurane on intestinal reflex vasoconstriction during hemorrhage was investigated in cats (n = 10) during basal chloralose-nitrous oxide anesthesia. Intestinal blood flow (IBF) was studied in a model with controllable intestinal perfusion pressures to exclude local myogenic vascular responses related to changes in intraluminal pressure. A jejunal segment, which was dissected free in situ, was perfused via an extracorporeal arterial circuit which included a roller pump and a variable arterio-venous shunt. Intestinal perfusion pressure was controlled by adjusting the shunt flow. IBF was measured (optical drop-recording) before and after hemorrhage (8% of estimated blood volume). The protocol included steady-state recordings at defined perfusion pressures (50, 75, 100, 125 and 150 mmHg in a randomized order; 6.7, 10.0, 13.3, 16.7 and 20.0 kPa, respectively) with and without the addition of 0.7% (MAC 1.0) isoflurane. IBF levels were consistently higher during isoflurane anesthesia than during basal chloralose anesthesia in the perfusion pressure range 75-150 mmHg (10.0-20.0 kPa). During basal anesthesia, a hemorrhage-induced decrease in IBF was demonstrated throughout the perfusion pressure range 50 to 150 mmHg (6.7-20.0 kPa). The magnitude of the hemorrhage-induced decrease in IBF was not significantly influenced by the addition of isoflurane. Thus, IBF, following hemorrhage, was significantly higher during isoflurane anesthesia than during basal chloralose anesthesia at perfusion pressures 50, 100, 125 and 150 mmHg (6.7, 13.3, 16.7 and 20.0 kPa).     

Effects of halothane,isoflurane and sevoflurane on ischemiareperfusion injury in the perfused liver of fasted rats

Background : Although intraoperative ischemia-reperfusion of the liver generally occurs under general anesthesia, little is known about the direct effect of anesthetic agents on hepatic injury due to this phenomenon. The effect of volatile anesthetics on ischemia-reperfusion injury was studied using isolated liver perfusion. Methods : The liver was isolated from 24-h-fasted male Sprague-Dawley rats and perfused through the portal vein with a modified Krebs-Ringer bicarbonate solution in a recirculating perfusion-aeration system. Ischemia was induced by reducing the baseline perfusion pressure from 1.2 to 0.2 kPa followed by reperfusion to baseline level. The ischemia-reperfusion injury was assessed by LDH release from the perfused liver. We studied the effect of halothane, isoflurane and sevoflurane on the ischemia-reperfusion injury during 20 min of control conditions, exposure of the liver to 60 min of ischemia and reperfusion for 90 min. Results : Ischemia was evident by reduced portal vein flow and oxygen consumption, and caused an increase in lactate production. Reperfusion caused a transient reduction in lactate production and a significant increase in LDH release. All anesthetics reduced hepatic oxygen consumption and increased the net lactate production during control conditions. Volatile anesthetics also significantly attenuated LDH release during reperfusion. The suppression of LDH release was observed even when isoflurane was administered during the reperfusion period, but not when it was administered only during ischemia. Conclusion : These results indicate that volatile anesthetics may protect the fasted liver from early, neutrophil-independent, ischemia-reperfusion injury by acting during the reperfusion phase.     

Effects of dose-dependent levels of isoflurane on cerebral blood flow in healthy subjects studied using positron emission tomography

Background:  In this study, we tested the hypothesis that escalating drug concentrations of isoflurane are associated with a significant decline in cerebral blood flow (CBF) in regions sub-serving conscious brain activity, including specifically the thalamus.
Methods:  Nine human volunteers received three escalating drug concentrations: 0.2, 0.4 and 1.0 MAC end-tidal inhalation. During waking, baseline and the three levels of sedation, a     O PET scan was performed.
Results:  Isoflurane decreased the bispectral index (BIS) values dose-dependently. Cardiovascular and respiratory parameters were maintained constant over time. No significant change in global CBF was observed. Throughout all three MAC levels of sedation, isoflurane caused an increased regional cerebral blood flow (rCBF) in the anterior cingulate and decreased rCBF in the cerebellum. Initially, isoflurane (0 vs. 0.2 MAC) significantly increased relative rCBF in the medial frontal gyrus and in the nucleus accumbens. At the next level (0.2 vs. 0.4 MAC), relative rCBF was significantly increased in the caudate nucleus and decreased in the lingual gyrus and cuneus. At the last level (0.4 vs. 1 MAC), relative rCBF was significantly increased in the insula and decreased in the thalamus, the cuneus and lingual gyrus. Compared with flow distribution in awake volunteers, 1 MAC of isoflurane significantly raised relative activity in the anterior cingulate and insula regions. In contrast, a significant relative flow reduction was identified in the thalamus, the cerebellum and lingual gyrus.
Conclusions:  Isoflurane, like sevoflurane, induced characteristic flow redistribution at doses of 0.2–1.0 MAC. At 1 MAC of isoflurane, rCBF decreased in the thalamus. Specific areas affected by both isoflurane and sevoflurane included the anterior cingulate, insula regions, cerebellum, lingual gyrus and thalamus.     

犬静脉注射乳化异氟醚最低肺泡有效浓度的研究

目的测定犬静脉注射乳化异氟醚的最低肺泡有效浓度(MAC静脉),并与吸入异氟醚麻醉时的最低肺泡有效浓度(MAC吸入)进行比较。方法将40只杂种犬平均分成静脉和吸入麻醉两组。应用序贯法和自身交叉法同时测定犬的MAC值。结果静脉组序贯法所测得的MAC静脉(0.94±0.10)%,与自身交叉法所测得的前6个交叉点的MAC静脉(0.89±0.14)%或全部交叉点的MAC静脉(0.93±0.13)%之间差异均无显著意义(P>0.05)。吸入组序贯法所测得的MAC吸入(1.29±0.10)%,与自身交叉法所测得的前6个交叉点的MAC吸入(1.24±0.06)%或全部交叉点的MAC吸入(1.33±0.09)%之间差异亦无显著意义(P>0.05)。但两组间比较MAC静脉均小于MAC吸入,差异有显著意义(P<0.05)。结论乳化异氟醚静脉麻醉时的MAC静脉明显小于吸入异氟醚麻醉时的MAC吸入,序贯法和自身交叉法对MAC的测定结果无明显影响。     

乳化异氟醚预处理对兔缺血再灌注心肌血流动力学的影响

近年来研究表明吸入麻醉药异氟醚可模拟缺血预处理发挥心肌保护作用，减轻再灌注期心肌功能抑制。以脂肪乳为载体静脉注射的乳化异氟醚可产生麻醉作用，但是否也具有心肌保护作用，尚无报道。为了进一步研究乳化异氟醚预处理对心肌缺血的保护效应，本实验在兔心肌缺血再灌注模型上测定不同时点血流动力学的有关指标，旨在探讨乳化异氟醚预处理对兔缺血再灌注心肌的血流动力学影响。     

Effects of halothane, isoflurane and sevoflurane on calcium-related contraction in porcine coronary arteries

Background: Volatile anaesthetics have a direct inhibitory effect upon epicardial coronary arterial smooth muscles (1–4). The site and mode of their action at the cellular level need to be clarified, which was the purpose of our study. The present investigation attempted to answer the question in what way volatile anaesthetics influence Ca²⁺-related contraction in isolated porcine epicardial coronary to understand their intracellular mechanism. Methods: Isolated helical strips of porcine epicardial coronary artery without endothelium were suspended for isotonic contraction recordings in Krebs-Ringer's solution. 9.4×10^-2 MK+, 2.5×10^-1 M Ca²⁺-induced shortening of the strips was regarded as the reference value (100%). After incubation in Ca²⁺-free solution with 10^-3 M ethlene glycol bis (β-aminoethyl ether)-N, N-tetraacetic acid (EGTA) for 60 minutes, the muscle strips were exposed to increasing Ca²⁺ concentrations (10^-4-10^-2) either in the presence or absence of 1.5 or 2.5 minimum alveolar concentration (MAC) halothane, isoflurane or sevoflurane, with 9.4×10^-2 M K⁺ bath solution. Results: All three drug groups produced apparent biphasic effects with a cumulative increase of Ca²⁺ concentration compared with control groups. An initial increase at low Ca²⁺ concentration was followed by a decrease of Ca²⁺-activated contractions. Isoflurane affected Ca²⁺-induced contraction significantly more than halothane and sevoflurane. Conclusions: The results imply that volatile anaesthetics influence Ca²⁺-dependent activity of coronary smooth muscle by complex mechanisms, which involve promotion of intracellular Ca²⁺ release and other mechanisms that alter sensitivity to calcium.     

Blockade of ATP-sensitive K+ channel abolishes the anti-ischemic effects of isoflurane in dog hearts

Background: Although isoflurane is reported to have a protective effect against ischemic damage on the myocardium, the mechanisms of this effect are not clear. Activation of adenosine triphosphate sensitive potassium (KATP) channels is indicated to protect myocardium during ischemia. Thus, it was hypothesized that if isoflurane could activate KATP channels, blockade of KATP channels would decrease its cardioprotective effect.
Methods: Mongrel dogs, anesthetized with morphine, urethane, and chloralose, were subjected to 15 min of left anterior descending coronary artery occlusion followed by 60 min reperfusion. The dogs were divided into three groups: the control group (n=8), IS0 group (n=8) and ISOGC group (n=8). In the IS0 and ISOGC groups, 1 MAC of isoflurane was administrated during ischemia and reperfusion. In the ISOGC group, 0.3 mg/ kg of glibenclamide, the KATP channel blocker, was given 45 min before ischemia. Full-thickness samples of myocardium were obtained and the concentrations of adenosine monophosphate, adenosine diphosphate, adenosine triphosphate (ATP), creatine phosphate and lactate in the endocardial portion of the myocardium were measured.
Results: The ischemia-reperfusion caused a 25.4% and 27.6% reduction of myocardial ATP in the control and ISOGC groups, respectively. In contrast, the IS0 group showed only 11.0% reduction of AT, which was significantly lower compared to the other groups ( P < 0.01).
Conclusions: Our results shows that blockade of the KATP channel abolishes cardioprotective effects of isoflurane in myocardial ischemia-reperfusion. The KATP channel may play a role in the ATP-sparing effect of isoflurane.