经皮开窗术治疗主动脉夹层引起的缺血

目的 评价经皮开窗术治疗主动脉夹层引起的内脏及下肢缺血。方法 6例主动夹层并发内脏及下肢缺血患者行经皮开窗术，所有患者皆是Stanford B型夹层，累及的血管有肾动脉（3条）、肠系膜动脉（1条）和下肢动脉（6条）。4例行单纯经皮开窗术，1例行开窗及左肾动脉支架置入治疗，1例行开窗及腹主动脉和双侧髂总动脉支架置入治疗。1例患者于开窗后1个月行支架移植物复合体（stent—graft）腔内隔绝术。结果 所有6例患者血管重建均成功，其中4例缺血症状消失，2例明显减轻。随访4～12个月，平均7．6个月，1例患者术后3个月死于主动脉破裂出血，余5例仍存活。无严重的手术相关并发症。结论 经皮开窗术或经皮开窗结合支架置入是1种安全、有效的治疗主动脉夹层引起的内脏及下肢缺血的方法。     

Collateral blood supply to an autotransplanted kidney

Collateral lumbar arterial blood supply to an autotransplanted kidney was angiographically documented in a patient with bilateral Wilms' tumor and postoperative transplant renal artery stenosis. During autotransplantation, most collateral pathways are interrupted. The development of a collateral circulation after autotransplantation may be postulated to begin with a vascular response to postoperative inflammation and adhesions. The small anastomotic pathways so formed may then dilate in response to ischemia resulting from renal artery stenosis.     

兔肾缺血-再灌注损伤后叶间动脉血流动力学变化与肾小管上皮Bcl-2表达的相关性

目的 探讨兔肾缺血-再灌注损伤后叶间动脉血流动力学变化及其与肾小管上皮Bcl-2表达的相关性.材料与方法 建立兔肾缺血-再灌注损伤模型,采用彩色多普勒血流显像(CDFI)和脉冲多普勒(PW)检测缺血-再灌注组(I/R组,n=24)兔和假手术组(S组,n=24)兔恢复血流后2h、8h、24h肾叶间动脉血流参数,包括收缩期峰值流速(Vmax)、舒张末期流速(Vd)、时间平均峰值流速(Tamax)、搏动指数(PI)和阻力指数(RI);以HE染色分析肾组织病理损伤程度;采用免疫组化SABC法检测肾小管上皮细胞中Bcl-2蛋白表达水平.结果 I/R组在2h时较S组无明显血流动力学改变,随着缺血-再灌注时间J延长,Vmax、PI、RI逐渐增大,24h时达高峰,其中RI24h较8h差异有统计学意义(P＜0.05);病理切片显示I/R组24h时肾小管上皮细胞坏死脱落程度最重;S组Bcl-2蛋白呈弱阳性表达,随着缺血-再灌注时间推移而逐渐上升,24h达高峰;叶间动脉Vmax、PI、RI与Bcl-2表达呈显著正相关(r=0.572、0.416、0.647,P＜ 0.05).结论 在兔肾缺血-再灌注中,肾叶间动脉血流动力学变化与肾小管上皮Bcl-2表达呈明显正相关,彩色多普勒超声对评价兔肾缺血-再灌损伤程度有较高价值.     

MR perfusion imaging of the kidney pre- and post-dipyridamole stress

Animal studies have demonstrated that renal MR contrast enhancement depends on the timing of image acquisition. Limited human studies have demonstrated effects of dipyidamole (DP) on total renal perfusion. This study assessed the effect of DP on total and regional renal perfusion using gated perfusion MRI for patients undergoing DP stress. Five subjects with no evidence of renal ischemia were examined at rest and after DP stress. Rest MRI images in the left kidney were acquired using electrocardiogram (ECG)-gated MR: turbo fast low-angle shot (FLASH); echo time (TE) = 12, repetition time (TR) = 6. flip angle = 12, inversion time (TI) = (100) 10 to 45 seconds after injection of gadopentetate dimeglumine. Stress was induced in the MRI scanner (DP, .56 mg/kg over 4 minutes) followed by stress MRI after a second bolus of gadopentetate dimeglumine in the same position and identical time intervals. MR signal in the whole left kidney and renal medulla and cortex pre- and post-DP demonstrated a 70% depression of total renal perfusion with relative preservation of cortical perfusion at the expense of medullary perfusion. Post-DP MR images demonstrated a decrease in cortical perfusion with an additional 29% depression of medullary perfusion (P < .001) with respect to cortical perfusion. Turbo FLASH MRI can provide adequate time and spatial resolution to demonstrate changes in renal perfusion. Depression of renal medullary perfusion after DP appears to be caused by the intrarenal effect of DP and may have clinical impact.     

Delayed, triangular, hyperdense, computed x-ray tomography images of the renal parenchyma following iodide injection. Interpretation of transient renal ischemia?

Three cases of renal ischemia diagnosed by Computed Tomography (CT) are presented. The pathophysiology of renal ischemia which accounts for the CT findings observer in these cases are reviewed. In the appropriate climate setting a diagnosis of renal ischemia may be made by CT, when a zone or zones of low attenuation after injection and enhancement of these same zones 6 to 72 hours later are observed in the kidney.     

肾缺血的肾脏功能影像学研究进展

明显的肾动脉狭窄或闭塞导致肾脏缺血,最终可能发展至终末期肾病,本文综述了MRI、CT及核医学等影像学检查手段关于肾缺血的肾功能影像学研究进展。     

Chronic renal ischemia: pathophysiologic mechanisms of cardiovascular and renal disease

Chronic renal ischemia caused by renal artery stenosis (RAS) elicits a complex biologic response. Although the traditional pathophysiologic pathways underlying renal ischemia have been well studied, there is emerging evidence that additional mechanisms may be responsible for producing many of the hemodynamic alterations and end-organ injury seen in patients with RAS, including persistent hypertension, renal insufficiency, and cardiac disturbance syndromes. A better understanding of these mechanisms may allow earlier identification of RAS, provide markers to predict the response to revascularization, or allow unique therapeutic targets for drug development. This and a subsequent article will explore the pathophysiologic and clinical implications of chronic renal ischemia.     

缺血预处理对急性肾缺血再灌注损伤时肾组织结构和ET的影响

目的 :探讨缺血预处理 (ischemiapreconditioningIPC )对大鼠肾缺血再灌注损伤的影响及其作用机制。方法 :30只雄性Wistar随机分为 3组。假手术组 (S)、缺血再灌注组 (I/R)、缺血预处理组 (IPC) ;放射免疫法检测各组肾皮质、髓质内皮素 (ET)含量 ,电镜和光镜观察肾组织病理改变及超微结构变化。结果 :与假手术组相比 ,缺血再灌注组ET含量明显升高 (P <0 .0 1) ,且髓质含量显著高于皮质 (P <0 .0 5 ) ;与缺血再灌注组相比预处理组皮质ET含量显著降低 (P <0 .0 5 ) ,髓质ET含量无明显差异 (P >0 .0 5 ) ,肾组织损伤病理评分显著降低 (P <0 .0 5 ) ,同时肾超微结构的破坏较轻。结论 :缺血预处理对肾缺血再灌注损伤具有保护作用 ,其作用机制可能是通过降低肾皮质ET的表达。     

Stanford B型胸主动脉夹层动脉瘤合并肾缺血的诊治(附3例报告)

为探讨合并肾缺血的StanfordB型胸主动脉夹层动脉瘤的诊断和处理 ,分析 1996年 1月至 2 0 0 0年 4月收治的StanfordB型胸主动脉夹层动脉瘤 2 9例 ,其中合并肾缺血 3例 ,为急性期 2例 ,慢性期 1例。急性期 1例发病后第 3天死亡 ,另 1例同时合并肾缺血和双下肢缺血 ,经夹层隔膜开窗术缓解 ;慢性期 1例经腔内隔绝术治愈夹层后肾缺血自行缓解。提示合并肾缺血的StanfordB型胸主动脉夹层动脉姑息性转流手术有助于缓解症状 ,提高生存率 ;对于慢性StanfordB型胸主动脉夹层动脉瘤合并肾缺血的患者 ,腔内隔绝术在治愈夹层动脉瘤的同时恢复了真腔供血 ,肾缺血可同时治愈     

MR imaging of blood oxygenation-dependent changes in focal renal ischemia and transplanted liver tumor in rat

The potential of using fast magnetic resonance (MR) imaging in conjunction with apnea-induced blood deoxygenation for the noninvasive monitoring of relative perfusion in the rat abdomen has been studied with two experimental models: glycer-ol-induced focal renal ischemia and transplanted liver tumor. Gradient-echo echo-planar imaging (GRE-EPI) (TE of 20 msec at 2 T) of liver and kidney was performed before, during, and after a 60-second apnea episode and then was followed in the same rat by contrast-enhanced (a) GRE-EPI and (b) T1-weighted spin-echo imaging (TR msec/TE msec = 200/6) with polylysine-(gadolmium-DTPA [diethylenetriaminepentaacetic acid]). The results indicate that a noninvasive vascular challenge due to apnea can be used for the detection of focal tissue perfusion abnormalities in rat kidney and liver tumor.     

Imaging Features of Gray-Scale and Contrast-Enhanced Color Doppler US for the Differentiation of Transient Renal Arterial Ischemia and Arterial Infarction

Objective

To characterize the imaging features on gray-scale and contrast-enhanced color Doppler US images which differentiate renal ischemia from renal infarction.

Materials and Methods

The segmental renal arteries of eight healthy rabbits were surgically ligated. In four of these rabbits, the ligated renal artery was released 60 minutes after arterial occlusion to cause transient ischemia. In the remaining four rabbits, the arterial ligation was retained to cause a permanent infarction. The gray-scale and contrast-enhanced color Doppler US imaging features of the involved renal parenchyma of both ischemia and infarction groups were compared with respect to the presence or absence of parenchymal swelling, echogenicity changes, tissue loss and perfusion defects.

Results

Parenchyma swelling, echogenic changes, tissue loss and perfusion defects were found to be more extensive in the infarction than the ischemia group. The hyperechoic areas reperfused with blood flow recovered normal echogenicity and perfusion, whereas the hyperechoic areas without reperfusion became renal infarcts.

Conclusion

Gray-scale and contrast-enhanced color Doppler US showed that the hyperechoic areas with reperfusion may reverse to normal parenchyma and allow the differentiation of renal ischemia from renal infarction.     

Absence of functional renal effects of uro-angiographic contrast media on post-ischemic rat kidneys

Water soluble ionic contrast media (CM) and glucose 5% were administered to Sprague-Dawley rats 36 hours after bilateral warm renal ischemia for 45 min. In all animals (n = 28) the renal ischemia caused a decrease of the absolute urinary creatinine output. Intra-arterial injection of glucose 5% or CM did not produce different patterns of absolute urinary creatinine output. The serum creatinine increased after 36 hours of reflow. When compared by means of a Mann-Whitney U-test to a normal median serum creatinine obtained in a separate group of 22 normal rats, the increase was statistically significant (p less than or equal to 0.01). The serum creatinine medians returned to a normal level after 24 hours. It seems therefore that 45 min of warm renal ischemia and 36 hours of reflow is an insufficient challenge to the rat kidney for the detection of the nephrotoxic properties of CM as opposed to when CM are injected during ischemia.     

Computed tomography of experimental acute renal ischemia.

The potential role of computed tomography (CT) in the detection of acute renal ischemia was assessed in nine mongrel dogs. Ischemia was produced by inflation of a balloon catheter in the main renal artery, with scans performed before, during, and after a 60-minute period of ischemia. A small but consistent increase in the attenuation value of ischemic renal parenchyma was observed. When intravenous contrast material was given, the ischemic kidney was markedly less enhanced than the contralateral, nonischemic kidney. By using the contralateral kidney for comparison, the ischemic kidney could be identified with or without the use of a contrast agent. Although calculations of mean pixel values were necessary when a contrast agent was not injected, the abnormal kidney could be easily recognized from the CT images themselves when intravenous contrast material was given. Because of the consistency with which the abnormalities were observed, we recommend a clinical trial of CT in suspected acute renal ischemia.     

In vitro magnetic relaxation times of the ischemic and reperfused rabbit kidney: concise communication

To assess the effects of renal ischemia and reperfusion on in vitro magnetic relaxation times (T1 = magnetization recovery, T2 = spin echo), we evaluated the spectroscopic characteristics of the renal cortex from 25 rabbits. Eight served as controls (Group 1), nine had one renal pedicle ligated for 1 hr (Group 2), and eight (Group 3) were occluded for 1 hr and reperfused for 30 min. For intra-animal comparison purposes, % H2O content, T1 (msec), and T2 (msec) of the ischemic (reperfused) kidney were normalized to the values from the normal kidney within the same animal. Renal ischemia consistently increased water content, which was exaggerated by reperfusion. In association with ischemia, T1 fell, and with reperfusion T1 lengthened. T2 increased with ischemia and declined from the peak ischemic effects with reperfusion.     

Functional evaluation of normothermic ischemia and reperfusion injury in dog kidney by combining MR diffusion-weighted imaging and Gd-DTPA enhanced first-pass perfusion

PURPOSE: To evaluate functional alterations of renal ischemia and reperfusion injury using MR diffusion-weighted imaging and dynamic perfusion imaging. MATERIALS AND METHODS: Twelve dogs were randomly divided into four groups. Animal renal ischemia was respectively induced for 30 (group 1), 60 (group 2), 90 (group 3), and 120 (group 4) minutes by left renal artery ligation under anesthesia. Using a 1.5 T MR system, true-FISP, TSE, EPI, and DWI sequences were acquired in five different periods; specifically, pre-ischemia, onset-ischemia, late ischemia, onset-reperfusion, and post-reperfusion. Moreover, a turbo-FLASH sequence (TR/TE/TI/FA = 5.8/3.2/400 msec/10 degrees ) with a temporal resolution of 1.16 seconds was acquired. Signal intensity (SI) was measured in the cortex, outer medulla, and inner medulla of kidney. Apparent diffusion coefficient (ADC) values were calculated, and SI was plotted as a function of time. RESULTS: In all animals, significant SI changes of the left kidney on T2/T2*WI were detected following ischemia-reperfusion insult compared to corresponding values of the right kidney. Following ligation, the ADC values decreased in all layers of the left kidney. Immediately after the release of ligation, ADC values in both outer and inner medulla of the left kidney remained lower than those of the right kidney in those animals which were induced with renal ischemia for 60, 90, and 120 minutes. In all groups, a uniphasic enhancement pattern was observed in the outer and inner medulla of the left kidney, accompanied by a decrease of the area under the curve. CONCLUSION: Our results suggest that MR diffusion-weighted imaging and dynamic perfusion imaging are useful in identifying renal dysfunction following normothermic ischemia and reperfusion injury.     

电刺激背侧中脑导水管周围灰质和再灌注对大鼠脑缺血的作用

目的 观察电刺激背侧中脑导水管周围灰质(periaqueductal gray,PAG)和再灌注对SD大鼠脑缺血后的神经损伤和自主神经功能的影响.方法 SD大鼠24只随机分为缺血5 h组、缺血2 h再灌注3 h组和脑缺血2 h加电刺激dPAG 1 h组.脑缺血模型采用大脑中动脉阻塞(middle cerebral artery occlusion, MCAO)的方法.实验过程中同时记录血压、心电图和肾交感神经活动.应用功率谱分析技术,获得了心率变异性和肾交感神经活动的频谱特征.计算了TTC染色后的梗死体积.结果 电刺激dPAG使缺血后梗死体积减小(P＜0.05),并提高自主神经系统的总活性.再灌注使缺血后梗死体积增大(P＜0.05),但对缺血后的自主神经功能障碍有很好的改善.结论 缺血后再灌注的优势主要在缺血远期,而电刺激有利于脑缺血后的早期恢复并有可能作为再灌注的辅助治疗手段而发挥作用.     

Study of acute renal ischemia in the rat using magnetic resonance imaging and spectroscopy

Magnetic resonance (MR) imaging and spectroscopy, chemical lactate measurements, and microscopic examinations were performed to investigate acute renal ischemia in rats. MR images (1H) and spectra (31P and 1H) were acquired on a 2.0-T superconducting small-bore magnet by using implanted coils. Occlusion of the renal artery induced a significant decrease in signal intensity of the renal parenchyma on T2-weighted images, which was most obvious in the outer medulla (-50 +/- 15%, n = 8, P less than 0.001) and was the result of venous congestion, as verified histologically, 31P spectroscopy demonstrated a drop in pH from 7.3 +/- 0.2 to 6.6 +/- 0.2 (n = 18, P less than 0.001), characterized by a time constant (Tc) in the same range as that of the depletion of ATP (2.3 +/- 1.3 min versus 1.9 +/- 1.2 min, n = 10, P = ns). By means of 1H spectroscopy, a lactate peak was detected within 1.5 to 4 min of ischemia, still increasing in intensity after 1 h of ischemia. The Tc of the lactate buildup (15.9 +/- 7.5 min, n = 8) was significantly longer than that of the drop in pH (P less than 0.005). The chemically measured intrarenal concentration of lactate was 1.3 +/- 0.5 mumol/g in control kidneys and 8.7 +/- 3.2 mumol/g (P less than 0.005) in kidneys made ischemic for 1 h. The present study demonstrated important features of acute renal ischemia: (a) acute ischemia induces venous congestion in the medulla; (b) accumulation of lactate is not the main cause of the intracellular acidification observed during ischemia.     

The influence of renal artery occlusion on tumor growth of experimental nephroblastomas (author's transl)]

Nephroblastomas are induced in rats with N-Methyl-N-Nitroso-Urea, and selective renal artery occlusion is performed. This procedure has the same effect like occlusion by embolization. The effect of renal artery occlusion on the growth rate of nephroblastmas is controlled by angiography and gross and microscopic examinations up to 70 days following ischemia, the results are compared with a group of untreated nephroblastoma rats. There is a marked reduction of tumor size and a decrease in tumor proliferation. There is an immediate tumor cell death induced by acute and complete ischemia. Collateral blood vessels cause residual arterial blood supply of tumor parenchyma. There seems to be a correlation between collateral blood delivery and tumor size. Even 70 days after permanent ischemia there are areas of obviously absolute normal tumor cells. The conclusion of this experimental study demonstrated that growth rate of tumors can be reduced by ischemia although potentially malignancy still remains. Clinical embolization therapy is justified only in nonoperable patients with hypernephroma and with massive hematuria.     

Combination of renal and adrenal scanning in the diagnosis of renovascular hypertension: case report.

Superimposition of an adrenal scan on a renal scan revealed a kidney defect not appreciated on the renal scan alone. The defect proved to be ischemia of the upper pole of the kidney. Resection of the lesion alleviated the patient's hypertension.     

活性氧作用下肾上皮细胞的药物保护及机理

观察了三磷酸腺苷（ＡＴＰ）、过氧化氢酶（ＣＡＴ）及异搏停（ＶＥＲ）对活性氧作用下的肾上皮细胞（ＲＥＣ）的保护效果，以探讨其可能机制。结果显示预先应用ＡＴＰ、ＣＡＴ和ＶＥＲ均使处于活性氧作用下肾上皮细胞培养基中的乳酸脱氢酶（ＬＤＨ）活性及细胞活力维持或接近正常水准。提示能量危机、氧自由基（ＯＦＲ）毒性和钙超载可能是细胞缺血／再灌注（Ｉ／Ｒ）损伤病理生理中的重要环节，向细胞供能、清除ＯＦＲ及维持钙稳态是防治肾Ｉ／Ｒ损伤的重要措施。