麝香保心丸增加大鼠心肌血流灌注量的药效动力学

目的　探讨麝香保心丸的药效动力学参数。方法　以大鼠心肌血流灌注量为指标进行测定。结果　麝香保心丸在大鼠体内呈一室模型特征 ,其最低起效剂量为 0 .5 4mg·kg-1,效应呈现半衰期为 0 .5 3h ,效应消除半衰期为 1.2 1h ,药效作用期为 3.4 8h ,效应达峰时间为 1.13h ,体存生物相当药量的吸收半衰期为 0 .2 3h ,消除半衰期为 1.4 7h ,达峰时间为 0 .88h。结论　麝香保心丸在体内具有吸收快、消除快和作用维持时间较短的特点     

外源性谷氨酸对豚鼠耳蜗复合动作电位及微音电位的影响

为观察和研究灌流外源性谷氨酸时复合动作电位（CAP）和微音电位（CM）的变化特点，行全耳蜗灌流不同浓度谷氨酸（1、5、10mmol/2）2h，由圆窗记录CAP和CM。结果显示：CAP的阈值变化与谷氨酸的灌流浓度有剂量依赖关系，灌流谷氨酸可以明显影响CAP的幅阈值，但对CM度及输入输出曲线的非线性特点没有显著的影响。研究表明谷氨酸对内毛细胞有选择性的作用，而对外毛细胞无明显作用。     

大肠癌根治术后门静脉置泵化疗预防肝转移

探讨大肠癌根治术后肝转移的预防方法，将54例大肠癌根治术后患者随机分成两组：A组（32例）门静脉插管灌注化疗，B组（22例）外周静脉化疗。两组病人术前检查术中探查均未发现肝转移灶。结果显示，肝转移率A组为15.4%（5例），B组为36.4%(8例）。1、2、3年生存率A级分别为98％、83％、61％，B组为90％、68％、42％。提示门静脉置泵化疗对预防大肠癌根治术后肝转移有显著意义。     

磁共振多技术成像对心肌存活性的实验研究

目的:评估磁共振多技术成像对判断心肌存活性的价值。材料和方法:冬眠心肌模型猪6只,于术前、术后2周及5周行MR多技术成像(包括:形态扫描、电影扫描、心肌灌注及心肌活性扫描),判断心肌缺血区及坏死区大小,与病理对照评价其诊断的准确性。结果:术后2周模型猪左室平均4.2±0.8个节段心肌缺血、平均0.5±0.8个节段心肌变性坏死;术后5周模型猪左室平均3.4±0.9个节段心肌缺血、平均0.3±0.4个节段心肌变性坏死;术后5周的病理提示左室平均3.3±0.5个节段缺血,0.2±0.4个节段坏死。结论:术后5周时左室心肌缺血及变性坏死的范围较2周时缩小,MR多技术成像对判断心肌存活性敏感,但轻度高估了心肌缺血及变性坏死的程度。     

Risk stratification in patients with remote prior myocardial infarction using rest-stress myocardial perfusion spect: prognostic value and impact on referral to early catheterization

BACKGROUND: Little is known about the prognostic value of myocardial perfusion single photon emission computed tomography (SPECT) in patients with remote prior myocardial infarction (MI). METHODS AND RESULTS: We identified 1413 consecutive patients with remote prior MI who underwent rest-stress myocardial perfusion SPECT. Semiquantitative visual analysis of 20 SPECT segments was used to define the summed stress, rest, and difference scores. The number of non-reversible segments was used as an index of infarct size. During follow-up (>or=1 year), 118 hard events occurred: 64 cardiac deaths (CDs) and 54 recurrent MIs. Annual CD and hard event rates increased significantly as a function of SPECT abnormality. For summed stress scores less than 4, 4 to 8, 9 to 13, and more than 13, the annual CD rates were 0.4%, 0.9%, 1.7%, and 3.5%, respectively (P =.002). Patients with small MI (<4 non-reversible segments) and no or mild ischemia (summed difference score or=4 non-reversible segments) had moderate to high annual CD rates (3.7%-6.6%) regardless of the extent of ischemia. Nuclear testing added incremental prognostic information to pre-scan information. Compared with a strategy in which all patients are referred to catheterization, a strategy that referred only those patients with a risk for CD of greater than 1% by myocardial perfusion SPECT resulted in a 41.6% cost savings. CONCLUSIONS: Myocardial perfusion SPECT adds incremental value to pre-scan information and is highly predictive and cost-efficient in the risk stratification of patients with remote prior MI. Patients with normal or mildly abnormal scan results or small MI in combination with absent or mild ischemia have a low risk for CD.     

Test-retest reproducibility of quantitative CBF measurements using FAIR perfusion MRI and acetazolamide challenge.

The reproducibility of quantitative cerebral blood flow (CBF) measurements using MRI with arterial spin labeling and acetazolamide challenge was assessed in 12 normal subjects, each undergoing the identical experimental procedure on two separate days. CBF was measured on a 1.5T scanner using a flow-sensitive alternating inversion recovery (FAIR) pulse sequence, performed both at baseline and 12 min after intravenous administration of acetazolamide. T(1) was measured in conjunction with the FAIR scan in order to calculate quantitative CBF. The CBF maps were segmented to separate gray matter (GM) from white matter (WM) for region-of-interest (ROI) analyses. Post- acetazolamide CBF values (ml/100 g/min, mean +/- SD) of 87.5 +/- 12.5 (GM) and 46.1 +/- 10.8 (WM) represented percent increases of 37.7% +/- 24.4% (GM) and 40.1% +/- 24.4% (WM). Day-to-day differences in baseline CBF were -1.7 +/- 6.9 (GM) and -1.4 +/- 4.7 (WM) or, relative to the mean CBF over both days for each subject, -2.5% +/- 11.7% (GM) and -3.8% +/- 13.6% (WM) Day- to-day differences in absolute post-ACZ CBF increase were -2.5 +/- 6.8 (GM) and 2.7 +/- 9.4 (WM) or, relative to the mean CBF increase over both days for each subject, -4.7% +/- 13.3% (GM) and 9.1% +/- 26.2% (WM). Thus, FAIR- based CBF measurements show satisfactory reproducibility from day to day, but with sufficient variation to warrant caution in interpreting longitudinal data. The hemispheric asymmetry of baseline CBF and post-acetazolamide CBF increases varied within a narrower range and should be sensitive to small changes related to disease or treatment.     

急性脑梗死患者脑血管异常与CT灌注成像参数的关联性研究

目的：探讨急性脑梗死患者脑血管异常与 CT 灌注成像（CTP）参数的相关性及其对临床预后的影响。方法临床纳入发病6 h 内颈内动脉系统急性脑梗死患者45例,所有患者均接受 CT 平扫、CTP 及 CT 血管造影（CTA）,分析 CTP 各个参数并评估患侧大血管情况。以血管情况分为血管正常组（17例）、血管狭窄组（10例）和血管闭塞组（18例）。另外,发病时、发病14 d 、发病90 d 分别采用美国国立卫生研究院卒中量表（NIHSS）、Barthel 指数（BI）、改良 Rankin 量表（mRS）评估患者的临床神经功能缺损、日常生活能力以及预后功能残疾水平。结果 CTA 检查显示：血管大致正常者17例,大脑中动脉狭窄者6例,大脑中动脉闭塞者8例,颈内动脉狭窄者4 例,颈内动脉闭塞者10例。3组患者在缺血区脑血流（CBF）面积、脑血容量（CBV）面积、梗死区相对 CBF（rCBF）、梗死区相对 CBV（rCBV）、局部灌注达峰时间（TTP）面积方面比较差异有统计学意义（P ＜0．05）;其中血管闭塞组以上参数均差于血管正常组,血管狭窄组仅 CBF 面积高于正常组,血管狭窄组与血管闭塞组比较,CBF 面积、CBV 面积、TTP 面积均较小,差异均有统计学意义（P ＜0．05）。发病时,各组间患者仅 NIHSS 评分差异有统计学意义（P ＜0．05）,血管正常组 NIHSS 评分明显低于血管狭窄组及血管闭塞组（P ＜0．05）。发病后14 d 、90 d ,各组患者 NIHSS 、BI 、mRS 评分差异均有统计学意义（P ＜0．05）,血管正常组各项评分均明显优于血管闭塞组（P ＜0．05）。结论急性脑梗死患者病灶侧血管异常与 CTP 显示的缺血范围存在密切的联系,能够作为患者临床预后的一个客观指标。     

Increased response of renal perfusion to the antioxidant vitamin C in type 2 diabetes.

BACKGROUND: Reactive oxygen species play a major role in the development of endothelial dysfunction. It is as yet unspecified whether increased oxidative stress contributes to endothelial dysfunction of the renal vasculature in patients with type 2 diabetes. METHODS: Renal haemodynamics were studied in 20 patients with type 2 diabetes and arterial hypertension (age 62 +/- 5 years) and 20 non-diabetic hypertensive patients at baseline and following infusions of the nitric oxide synthase inhibitor, N(G)-monomethyl-L-arginine (L-NMMA; 4.25 mg/kg); the substrate of nitric oxide synthase, L-arginine (100 mg/kg); and the antioxidant, vitamin C (3 g, co-infused with L-arginine 100 mg/kg). RESULTS: The response of renal plasma flow (RPF) to L-NMMA (-54 +/- 62 and -45 +/- 42 ml/min/1.73 m(2); P = NS) and L-arginine (+46 +/- 36 and +49 +/- 25 ml/min/1.73 m(2); P = NS) was not different between diabetic and non-diabetic patients. In contrast, vitamin C induced a more pronounced increase in RPF in diabetic than in non-diabetic patients when co-infused with L-arginine (+71+/-47 and +43+/-33 ml/min/1.73 m(2); P<0.05). CONCLUSIONS: The difference in the response of renal perfusion to an antioxidant suggests increased formation of reactive oxygen species and thereby reduced nitric oxide bioavailability in the renal vasculature of patients with type 2 diabetes.     

Effects of xenon anaesthesia on intestinal oxygenation in acutely instrumented pigs

Background. Xenon is a narcotic gas that might be able to replacevolatile anaesthetics or nitrous oxide due to its favourablepharmacological properties, such as providing haemodynamic stability.Intestinal oxygenation is affected by most volatile anaestheticsas a result of cardiodepressive effects. Reducing oxygenationof the gut might be a factor leading to perioperative organdysfunction. This animal study was designed to assess the effectsof xenon on intestinal oxygenation. Methods. After ethical approval, 24 anaesthetized, acutely instrumentedpigs were randomly assigned to three groups: nine animals receivedxenon anaesthesia with inspiratory concentrations of 0, 20,50 and 65% in addition to their basic i.v. anaesthesia, nineanimals served as a study control group, and five animals wereused to assess model stability. Measurement of systemic andregional haemodynamic and oxygenation parameters was made 30min after changing the xenon concentration. Results. Xenon elicited dose-dependent systemic haemodynamicchanges: heart rate and cardiac output decreased by 30%, whilemean arterial pressure was stable. Superior mesenteric arteryblood flow was lower in the xenon group. Vascular resistanceof the superior mesenteric artery increased. The small intestinaloxygen supply decreased with increasing xenon concentration;the mucosal tissue oxygen partial pressure decreased but didnot reach hypoxic (<5 mm Hg) values. Serosal tissue oxygenpartial pressure was maintained. Conclusions. Xenon, in addition to basic i.v. anaesthesia, eliciteda decrease in cardiac output and maintained mean arterial pressure.Intestinal oxygenation was maintained, although regional macrohaemodynamicperfusion decreased. Xenon does not impair intestinal oxygenationunder physiological conditions.      

Antegrade selective cerebral perfusion with mild hypothermic systemic circulatory arrest during thoracic aortic surgery

Objective Antegrade selective cerebral perfusion (ASCP) and retrograde cerebral perfusion (RCP) have proven to be reliable methods of brain protection during aortic surgery. These techniques are usually accompanied by systemic circulatory arrest with moderate hypothermia (24–28°C) or deep hypothermia (18–24°C). However, hypothermia can lead to various problems. The present study therefore reports results for thoracic aorta replacement using ASCP with mild hypothermic systemic arrest (28–32°C).

Design Between 1995 and 2003, 68 consecutive patients underwent repair of the ascending aorta and/or aortic arch. Mild hypothermic ASCP was utilized in 31 cases, moderate hypothermic ASCP in 20, and deep hypothermic RCP in 17. Various parameters were compared between the mild hypothermic ASCP, moderate hypothermic ASCP, and RCP.

Results Hospital mortality was 10.3%, with no significant differences observed between any groups. Permanent neurological dysfunction was 8.8%, and no significant differences were observed between any groups. Mild hypothermic ASCP displayed significantly decreased transfusion volume, intubation time, and ICU stay.

Conclusions Use of ASCP with mild hypothermic systemic circulatory arrest during aortic surgery resulted in acceptable hospital mortality and neurological outcomes. ASCP with mild hypothermic arrest allows decreased transfusion volume and reduced duration of intubation and ICU stay.