Cyclosporin A Has a Protective Effect with Induced Upregulation of Hsp70 and nNOS on Severe Spinal Cord Ischemic Injury in Rabbits

The purpose of this study is to ascertain the neuroprotective effect of cyclosporin A on the 25-min surgical ischemia model in the spinal cords of rabbits with neuropathological correlation and histoimmunochemical analyses measuring HSP70 and neuronal NOS (nNOS). New Zealand white rabbits were randomly divided into four groups (each n = 8): the C2, C7, Cs2, and Cs7 groups. The C2 and C7 groups underwent a 25-min surgical aortic cross-clamp without intervention and were sacrificed respectively on day 2 and on day 7 postoperatively. The Cs2 and Cs7 groups received cyclosporin A (25 mg/kg) intravenously 15 min after the 25-min cross-clamp and were sacrificed respectively on day 2 and day 7 postoperatively. Neurologic functions were evaluated on postoperative days 2 and 7 using the Tarlov scoring system. Then the rabbits were sacrificed for histopathologic observation. HSP 70 and nNOS stains with TUNEL assay were done for the C2 and Cs2 groups. All rabbits survived the experimental procedure. Tarlov's score for the Cs7 group (2.75 ± 0.89) was significantly higher than that of the C7 group (1.25 ± 1.39) (p <. 05). Tarlov's score of the Cs7 group was also statistically higher on day 7 than on day 2 (p <. 05). Strong correlation between the neurological and histological scorings was found. The TUNEL assay showed that the mean number of positive cells in the C2 group was 17.5 ± 22.6 and in the Cs2 group was 12.5 ± 11.1, but there was no statistically significant difference between the groups. There was more expression of HSP70 and nNOS in the cyclosporin groups than in the ischemia groups. In conclusion, this study demonstrates that cyclosporin A reduces neurological injury in the rabbit model of 25-min spinal cord ischemia. The neuroprotective effect of cyclosporin A against ischemia seems to be related to overexpressions of nNOS and HSP70.     

Neuroprotective effect of KR-31378, a novel potassium channel activator, on spinal cord ischemic injury in rabbits.

Neurologic deficits after the surgical repair of thoracic and thoracoabdominal aortic disease are devastating complications. Recently, pharmacologic preconditioning with potassium channel openers was reported to protect the spinal cord against neurologic injury in a model of spinal cord ischemia. A novel benzopyran derivative with an N-cyanoguanidine group, KR-31378, has been synthesized as a new therapeutic agent against ischemic injury. In the present study, we evaluated the protective effects of KR-31378 on spinal cord ischemic injury and compared its neuroprotective activities and hemodynamic stabilities with those of diazoxide. Thirty-four New Zealand white rabbits were randomly divided into four groups: ischemia group (n = 10, 25 min of aortic cross-clamping without any intervention), diazoxide group (n = 8, diazoxide [5 mg/kg] intravenously 15 min before the 25-min cross-clamping), KR20 group (n = 8, KR-31378 [20 mg/kg] intravenously 30 min before the 25-min cross-clamping), and the KR50 group (n = 8, KR-31378 [50 mg/kg] intravenously 30 min before the 25-min cross-clamping). Neurologic functions were evaluated for 72 h postoperatively using modified Tarlov's scores. All rabbits were sacrificed for histopathologic observations after finally scoring neurologic function. All rabbits but three survived. The rest were completely evaluated 72 h postoperatively. Unlike diazoxide-treated rabbits, KR-31378-treated rabbits showed relatively stable hemodynamics. Tarlov's score outcomes showed a marked improvement in the diazoxide group, in the KR20 group, and in the KR50 group compared to the ischemia group (p = .005, .002, and .001, respectively). However, Tarlov's scores in the KR50 group were not significantly different from those of the diazoxide group. Histopathologic data were not significantly different between the groups, but the degree of degenerative change in motor neurons showed a significant correlation with Tarlov's scores 3 days postoperatively (gamma = -.378, p = .036). Thus, the administration of KR-31378 before the aortic cross-clamping resulted in a significant improvement in neurologic outcome with stable hemodynamics in this rabbit model.     

腺苷A1受体系统在兔脑预缺血延迟相保护效应中的作用

目的 探讨腺苷A1受体系统在兔脑预缺血延迟相保护效应中的作用。方法 股动脉放血至平均动脉压35－40mmHg时,阻断双侧颈总动脉诱导脑缺血。脑缺血3min存活3d（预缺血处理）后、脑缺血10min（预缺血延迟相保护模型）;用腺苷A1受体激动剂氮6－环戊基腺苷（CPA）代替预缺血处理,用其拮抗剂8－环戊基－1,3－二丙基黄嘌呤（DPCPX）阻断该受体;免疫组化分析热休克蛋白70（SHP70）表达。观察缺血3d后海马CA1区正常神经密度和HSP70的表达。结果 （1）CPA能减轻脑缺血损害,但其保护作用不如预缺明显（约占后者的70％）,DPCPX阻断该受体后,预缺血延迟相保护作用消失;（3）3min脑预缺血神经元无损害,但伴HSP70明显表达;DPCPX阻断腺苷A1受体后,3min脑预缺血发生明显损害,且HSP70表达明显削弱。结论 （1）预缺血延迟相保护作用与腺苷A1受体系统激活有关;（2）DPCPX阻断预缺血延迟相保护作用的机制与削弱HSP70表达有关。     

Cyclosporin A reduces delayed motor neuron death after spinal cord ischemia in rabbits

BACKGROUND: Spinal cord ischemia has varied etiologies, and in some cases, may develop into paraplegia. This is attributable to the vulnerability of spinal motor neurons to ischemia. We evaluated the potential of the immunosuppressant cyclosporin A for treatment of spinal motor neuron damage caused by ischemia. METHODS: Twenty-eight rabbits were randomized into four groups of 7 animals each: group A (cyclosporin A not administered), group B (2.5 mg/kg cyclosporin A), group C (25 mg/kg cyclosporin A), and group S (sham-operated). The spinal cord ischemia model was created by a 15-minute occlusion of the aorta just caudal to a renal artery with a balloon catheter. Administration of cyclosporin A began 30 minutes after restoration of blood flow. The spinal cords were removed after 7-day monitoring of neurologic function. Pathology specimens were prepared, and after staining them with hematoxylin-eosin, viable motor neurons in the ventral spinal cord were counted under light microscopy. RESULTS: At 7 days after reperfusion, recovery of motor function was seen at varying degrees in groups B and C, whereas all animals in group A continued to exhibit paraplegia. In group C, most of the animals recovered to the baseline level, before creation of the ischemia model. A significant difference in numbers of viable neurons was found in group A (cell count, 10.1 +/- 4.7) and group C (cell count, 22.2 +/- 8.0) (p < 0.05). Higher numbers of viable motor neurons corresponded to a greater recovery of motor function. CONCLUSIONS: These results suggest that cyclosporin A administration is effective against neuronal damage caused by spinal cord ischemia.     

Effect of post-ischemic hypothermia on spinal cord damage induced by transient ischemic insult in rabbits

OBJECTIVE: The effect of post-ischemic mild hypothermia applied immediately after induced transient ischemia on the extent of neuronal damage to the spinal cord was investigated in rabbit. SUBJECTS AND METHODS: A 15-minute period of transient abdominal aortic occlusion for spinal cord ischemia at a rectal temperature of 37.3 +/- 0.3 degrees C was performed just below the left renal vein via median laparotomy. Three groups of rabbits were investigated; Group 1 (n = 8) subjected to ischemia and reperfused at the same temperature for 7 hours, Group 2 (n = 8) also subjected to ischemia and then to 6 hours of systemic hypothermia (32.5 +/- 0.5 degrees C), and Group 3 (n = 8) non-ischemic controls. All the rabbits in Group 1 and Group 2 were sacrificed at 1 week after ischemic injury. Spinal cord sections were examined microscopically to determine the extent of ischemic neuronal damage. RESULTS: The mean modified Tarlov's score at 1 week after ischemic injury was 0.5 +/- 0.8 in Group 1, whereas it was 4.4 +/- 1.4 (p < .001) in Group 2. The mean total number of surviving neurons within examined sections of the spinal cord was significantly greater in Group 2 than in Group 1 (Group 1: 81 +/- 66.1 vs Group 2: 300.9 +/- 154.1, p < .001). CONCLUSION: Post-ischemic hypothermia induced immediately after reperfusion significantly reduced ischemia-induced neuronal damage in rabbit.     

高强度聚焦超声治疗VX2骨肿瘤的免疫变化

目的　探讨高强度聚焦超声 (HIFU )治疗骨肿瘤前后的免疫学变化。方法　将新西兰大白兔分为HIFU治疗组 (2 3只 )及正常对照组 (10只 ) ,对HIFU治疗组兔建立VX2移植性骨肿瘤模型 ,2周后接受HIFU治疗 ,于不同时间处死 ,免疫组织化学染色观察HSP70表达的变化 ,并在治疗前后抽血检测CD2 5变化。结果　治疗前肿瘤组织HSP70阳性表达细胞数量少 ,治疗后即刻直到 2 1d一直呈强阳性表达且阳性表达的细胞数明显增加。治疗前CD2 5为 7.83± 2 .0 3与正常兔 13 .18± 3 .47比较差异有显著性 (P <0 .0 5 ) ;治疗后增高为 15 .5 5± 2 .69,与治疗前比较差异有非常显著性 (P <0 .0 1)。结论　HIFU治疗后骨恶性肿瘤组织HSP70、CD2 5的数量增多 ,可递呈特异性抗原给T细胞 ,刺激T细胞增殖 ,提高机体抗肿瘤的免疫作用     

不同预处理对肝硬化兔缺血再灌注肝组织HSP70及ET-1表达的影响

目的:探讨两种预处理方式,即经典缺血预处理(IPC)与肢体缺血预处理(LIPC),对肝硬化兔肝缺血再灌注(I/R)损伤的保护作用及可能的作用机制。方法:皮下注射CCl4-橄榄油溶液制备兔肝硬化模型,随后将模型兔随机分为假手术组,肝I/R组(I/R组),IPC+肝I/R组(IPC组),LIPC+肝I/R组(LIPC组),每组7只。肝I/R模型制作方法:阻断入肝血流30 min,再灌注2 h;IPC诱导方法:在行肝I/R处理前阻断入肝血流10 min,开放10 min;LIPC诱导方法:在行肝I/R处理前24 h,采用止血带捆扎兔单侧后肢5 min,再开放5 min,重复3次。各组于再灌注2 h后切取肝组织,行组织形态学观察,用ELISA法测定内皮素1(ET-1)含量及Western blot法检测热休克蛋白(HSP70)的表达。结果:与假手术组比较,其余各组在肝硬化病变的基础上均出现不同程度的变性、水肿和炎性细胞浸润,但IPC组与LIPC组明显轻于I/R组,而LIPC组及IPC组间病变程度无明显差异;与假手术组比较,其余各组肝组织ET-1含量和HSP70的表达均明显增加(均P<0.05),但IPC组与LIPC组肝组织ET-1含量低于I/R组,HSP70的表达高于I/R组(均P<0.05),而上述2项指标在LIPC及IPC组间均无统计学差异(均P>0.05)。结论:LIPC和IPC均能对肝硬化肝I/R损伤有保护作用,且保护强度相似,其机制可能均与抑制ET-1的释放及增加HSP70的表达有关;LIPC具有无创性,可能具有更大的临床应用前景。     

The time course of acquisition of ischemic tolerance and induction of heat shock protein 70 after a brief period of ischemia in the spinal cord in rabbits

We examined the time course of development of ischemic tolerance in the spinal cord and sought its mechanism exploring the expression of heat shock protein 70 (HSP70). Spinal cord ischemia was produced in rabbits by occlusion of the abdominal aorta. In Experiment 1, neurologic and histopathologic outcome was evaluated 48 h after prolonged ischemia (20 min) that was given 2 days, 4 days, or 7 days after a short period of ischemia (ischemic pretreatment) sufficient to abolish postsynaptic component of spinal cord evoked potentials. Control animals were given prolonged ischemia 4 days after sham operation. In Experiment 2, HSP70 expression in motor neurons after pretreatment without exposure to prolonged ischemia was examined by immunohistochemical staining. Ischemic pretreatment 4 days (but not 2 days or 7 days) before 20 min ischemia exhibited protective effects against spinal cord injury. In the cytoplasm, HSP70 immunoreactivity was mildly increased after 2, 4, and 7 days of ischemic pretreatment. However, the incidence of nuclear HSP70 immunoreactivity 2 days, 4 days, and 7 days after ischemic pretreatment was 2 of 6 animals, 4 of 6 animals, and 1 of 6 animals, respectively (none in the control group). These results suggest that ischemic tolerance is apparent 4 days after ischemic pretreatment and that HSP70 immunoreactivity in the nucleus may provide some insight into the mechanisms of ischemic tolerance in the spinal cord.     

A study of the myocardial protective effect of rapid cooling based on intracellular Ca, intracellular pH, and HSP70.

Objective: It has been reported that rapid cooling of the heart during normothermic coronary circulation at reperfusion after ischemia promotes early recovery of cardiac function due to the positive inotropic effects on the myocardium produced by cooling. The aim of the present study was to investigate the myocardial protective effect of rapid cooling by measuring heat shock protein (HSP) levels and examining the relationship between cardiac function, intracellular Ca concentration, and intracellular pH after rapid cooling. Methods: Isolated perfused rat hearts were subjected to ischemia for 60 minutes at a myocardial temperature of 37 degrees C. One group of hearts (group R) was subjected to 3 minutes of rapid cooling (相似文献   

乙醇预处理与HSP70的诱导及对肝脏缺血再灌流损伤的影响

目的探讨乙醇预处理对肝脏缺血再灌流损伤的影响以及与热休克蛋白70诱导的关系。方法雄性成年Wistar大鼠232只,胃饲乙醇浓度40%,剂量为5 g/kg体重,随机分为5组:正常对照组(N组)、胃饲乙醇组(E组)、缺血组(IR组)、生理盐水预处理组(NPC组)、胃饲乙醇预处理组(EPC组)。动物手术采用门静脉转流下的肝脏缺血模式,肝门阻断时限为90 min,于再灌流0、13、、6、12、24、72 h活杀留取血液及肝脏标本。结果EPC组3、6 h血清ALT(1 230.88±132.50、888.88±126.67)IU/L、AST(1 866.38±61.77)(、1 433.88±42.74)IU/L均明显低于IR组及NPC组,肝脏病理改变较轻,而肝组织HSP70含量高于后者。结论乙醇预处理可以减轻大鼠肝脏90 min的缺血再灌流损伤,其肝脏保护作用与肝组织HSP70升高相一致,HSP70可能是其发挥肝脏保护的物质基础之一。     

Effects of intrathecal bupivacaine in conjunction with hypothermia on neuronal protection against transient spinal cord ischemia in rats

BACKGROUND: Excitotoxic neuronal injury from ischemia may be reduced by local anesthetics. We investigated the neuroprotective effects of intrathecally administered bupivacaine and hypothermia in a rat model of transient spinal cord ischemia. METHODS: PE-10 intrathecal catheter-implanted male Sprague-Dawley rats were randomly assigned to one of four groups: normothermia (NT) and hypothermia (HT) groups (given 15 microl of normal saline) and bupivacaine (B) and bupivacaine-hypothermia (BHT) groups (given 15 mul of 0.5% bupivacaine). Transient spinal cord ischemia was induced by inflation of a 2F Fogarty catheter placed in the aortic arch for 12 min. The rectal temperature was maintained at 37.0 +/- 0.5 degrees C for the NT and B groups, and at 34.5 +/- 0.5 degrees C for the HT and BHT groups. Motor and sensory deficit scores were assessed 2 and 24 h after reperfusion. Lumbar spinal cords were harvested for histopathology and immunoreactivity of heat shock protein 70 (HSP70). RESULTS: After reperfusion, the motor and sensory deficit scores of the NT group were significantly higher than those of the HT (P < 0.05) and BHT (P < 0.001) groups. Significant differences were evident in the motor and sensory deficit scores between the HT and BHT groups at 24 h (P < 0.05). Neuronal cell death and immunoreactivity of HSP70 were frequently observed in the NT and BT groups, but not in the HT and BHT groups. CONCLUSIONS: These results collectively suggest that intrathecal bupivacaine does not provide neuroprotection during normothermic transient spinal cord ischemia in rats, but enhances the neuroprotective effects of hypothermia.     

Protective effect of prostaglandin E1 against ischemia of spinal cord during aortic cross clamping

PURPOSE: The purpose of this study was to investigate whether or not 5-minute segmental intraaortic perfusion of prostaglandin E1 (PGE1) in the preischemic period has a protective effect against spinal cord ischemia during aortic cross clamping. METHODS: The rabbits were divided into two groups. In group A (n = 6), the infrarenal aorta was segmentally cross clamped and the segment was perfused for 5 minutes with blood and saline solution at first. The aorta was kept cross clamped without perfusion for a subsequent 20 minutes. In group B (n = 6), the infrarenal aorta was segmentally cross clamped and the segment was perfused for 5 minutes with blood and saline solution containing PGE1 of 100 ng/kg/min at first. The aorta was kept cross clamped without perfusion for a subsequent 20 minutes. After the aorta was declamped, the experimental animals recovered from the anesthesia. Twenty-four and 48 hours after the operation, the hind limb function was estimated with Tarlov's grade. Then, the animals were killed for pathologic study. RESULTS: The systolic arterial pressures measured at the left common carotid artery through the experiment were not significantly different between the two groups. The perfusion of the aortic segment between the proximal and distal clamp was nonpulsatile. The perfusion pressures of the aortic segments at 5 minutes after aortic cross clamping were 29 +/- 6 mm Hg and 33 +/- 6 mm Hg in groups A and B, respectively. No significant differences were seen between the two groups. In group A, the hind limb functions evaluated with Tarlov's grade after 24 hours and 48 hours were 0 to 3 (1.5 +/- 1.4) and 0 to 3 (1.3 +/- 1.4), respectively. In group B, these were 3 to 4 (3.5 +/- 0.5) and 3 to 4 (3.7 +/- 0.5), respectively. A significant difference was seen between the two groups (P <.05). In the ventral horn of the L5, L6, and L7 segments, large motor neurons that seemed viable were more preserved in group B than in group A. CONCLUSION: Segmental intraaortic perfusion of PGE1 in the preischemic period reduced neurologic damage of spinal cord ischemia.     

Protection "outside the box" (skeletal remote preconditioning) in rat model is triggered by free radical pathway

BACKGROUND: Remote preconditioning (RPC) for myocardial protection had been demonstrated in several organs, such as the kidney and mesentery artery. The aim of study was to investigate the effect of skeletal ischemia/reperfusion on coronary artery occlusion-induced myocardial infarction and to investigate the role of the free radicals. MATERIAL AND METHODS: RPC was performed in rats by a repeated four-cycle 10-min ischemia-reperfusion of femoral artery. Four experimental groups were included: I, sham group; II, RPC only; III, infarction only; and IV, which incorporated both RPC and infarction. A chemiluminescence study showed significant elevation of free radicals in groups with RPC, and pretreated mercaptopropionyl-glycine (MPG), a free radical scavenger, abolished the production of free radicals. RESULTS: The infarct size was significantly reduced for group IV (24.7 +/- 8.8%) compared with group III (51.4 +/- 9.1%; P < 0.001), and the effect was abolished by pretreatment with MPG (49.2 +/- 6.3% in MPG + III versus 50.1 +/- 8.2% in MPG + IV; P > 0.05). Cardiac enzymes also revealed significant decrease in the level for group IV compared with group III, and the protective effect could be abolished by MPG. Western blotting of heat shock protein (HSP) revealed that consistent elevation of HSP 25 and 70 in groups II, III, and IV, and the elevation can be abrogated by pretreatment with MPG. The expression of the antioxidant enzymes, Mn-superoxidase dismutase and glutathione peroxidase, in the area of risk were consistently elevated in groups II, III, and IV, similar to HSP. CONCLUSIONS: The skeletal RPC in rats can produce a protective effect in an infarction model that may be triggered through free radical pathway, and the protective effect was associated with HSP and antioxidant enzymes.     

Gene transfer of heat shock protein 70 protects lung grafts from ischemia-reperfusion injury.

BACKGROUND: We recently demonstrated that heat stress induction of heat shock protein 70 (HSP70) in donor animals before harvest decreases posttransplant ischemia-reperfusion injury in preserved rat lung isografts. The purpose of this study was to investigate the feasibility of HSP70 gene transfection into rat lung isografts using an adenoviral vector, and to study the effects of gene expression on subsequent ischemia-reperfusion injury. METHODS: In preliminary studies to determine the optimal titer, animals were injected with various titers of adenovirus-HSP70 (saline, 5 x 10(9), 1 x 10(10), and 2 x 10(10) plaque forming units [pfu]) and sacrificed 5 days after injection. To determine the optimal exposure time, animals were sacrificed at different times (0, 6, 24, and 72 hours) after intravenous injection of adenovirus-HSP70. In a subsequent series of transplant experiments, donors were allocated to three groups according to transfection strategy. Group 1 (n = 8) donors received 5 x 10(9) pfu adenovirus-HSP70 intravenously, group 2 (n = 7) donors received 5 x 10(9) pfu adenovirus-beta-galactosidase (as a virus control), and group 3 (n = 7) donors received saline and served as a negative control. Twenty-four hours after treatment all grafts were harvested and stored for 18 hours before orthotopic left lung transplantation. Twenty-four hours after implantation animals were sacrificed for assessment. The expression of HSP70 was assessed by Western blot analysis. RESULTS: In preliminary studies, HSP70 was detectable even at low titers (5 x 10(9) pfu) of adenovirus-HSP70, and was detectable at low levels as early as 6 hours after intravenous administration. Heat shock protein 70 expression was maximal at 24 hours. In transplant experiments, Western blot analysis showed that overexpression of HSP70 occurred in the HSP70-transfected lungs. The mean arterial oxygenation 24 hours after reperfusion in group 1 was superior in comparison with other groups (p < 0.05). Wet to dry weight ratio (p < 0.05) and myeloperoxidase activity (p < 0.05) were also significantly less in group 1 grafts compared with the other groups. CONCLUSIONS: This study demonstrates that in vivo, donor adenovirus-mediated gene transfer of HSP70 decreases subsequent ischemia-reperfusion injury in rat lung isografts.     

Epidural cooling for the prevention of ischemic injury to the spinal cord during aortic occlusion in a rabbit model: determination of the optimal temperature

PURPOSE: This experiment was designed for the determination of the optimal epidural cooling temperature for the allowance of spinal cord protection with minimal side effects during an aortic occlusion-induced spinal cord ischemia model in rabbits. METHODS: Spinal cord ischemia was induced in rabbits with infrarenal aortic occlusion for 40 minutes. Spinal cord cooling was effected with epidural infusion of normal saline solution at the following different temperatures: group 1, 17 degrees C (n = 6); group 2, 24 degrees C (n = 6); group 3, 32 degrees C (n = 6); and group 4, 39 degrees C (n = 3). Sham-operated rabbits without aortic occlusion were used as controls with epidural infusion at healthy body temperature (39 degrees C; n = 3). Motor function was assessed at 48 hours with Tarlov's criteria, and the animals were killed. The spinal cord was sectioned into multiple segments, and semiquantitative histologic scoring (0 to 5) was used to grade ischemic injury. RESULTS: Cooling solution and spinal cord temperatures showed linear correlation (r = 0.95). All the rabbits in groups 1 (except one with mild weakness), 2, and 3 were neurologically intact, and all in group 4 had paraplegia develop (P < .001). One rabbit in group 1 died from increased intracranial pressure (ICP). Mean blood pressure, ICP, and body temperature were similar among the groups. Histology correlated with the clinical findings. In groups 1 and 2, minimal histologic changes were noted. Low-grade ischemic changes were present in group 3 in the low-lumbar and mid-lumbar segments. Severe ischemic injury occurred at the same segments in group 4 (P < .05). CONCLUSION: These study results suggest that in rabbits satisfactory spinal cord protection during aortic occlusion can be achieved at moderate regional hypothermia (24 degrees C). Large volume infusion for the achievement of profound hypothermia may cause deleterious effects of increased ICP and is not warranted.     

The role of aspirin and dipyridamole on vascular DNA synthesis and intimal hyperplasia following deendothelialization

Platelets are implicated both in acute thrombotic events and, through platelet-derived growth factor, in the development of intimal hyperplasia. We have investigated, in vivo, the influence of aspirin and dipyridamole on vascular smooth muscle cell proliferation and DNA synthesis following balloon catheter injury. Fifty-eight male, New Zealand white rabbits were divided equally into two groups; the test group was fed aspirin (14 mg/kg/day) and dipyridamole (9 mg/kg/day) from 2 days prior to surgery until sacrifice at 1, 2, 3, 4, 7, 14, or 28 days after injury. All animals were sacrificed 1 h after injection of [3H]thymidine and the smooth muscle cell DNA specific activity and total kinetic activity were determined. Intimal hyperplasia was measured by light microscopy and intimal nuclear proliferation was determined by counting nuclei per millimeter of internal elastic lamina. Nuclear proliferation was maximal at 14 days (25 +/- 1.2) but intimal hyperplasia was still increasing at 28 days. DNA specific activity after 24 hr (test: 4 +/- 2 dpm/micrograms DNA; control: 3.3 +/- 3 dpm/micrograms DNA) was similar to basal levels in uninjured rabbits. DNA synthesis peaked in both groups between the second and third day (test: 177 +/- 27 dpm/micrograms DNA; control: 185 +/- 39 dpm/micrograms DNA) and then declined slowly toward baseline values. There was no significant difference between treated and normal rabbits in either [3H]thymidine incorporation, nuclear proliferation, or development of intimal hyperplasia despite 90% inhibition of platelet aggregation and a significant reduction (78%) in [14C]serotonin release following collagen challenge (6 micrograms/ml).(ABSTRACT TRUNCATED AT 250 WORDS)     

Prevention of reperfusion injury of the ischemic spinal cord: use of recombinant superoxide dismutase

We investigated the effect of recombinant superoxide dismutase, an oxygen free radical scavenger, on the prevention of reperfusion injury of the ischemic spinal cord. Somatosensory evoked potentials (SEPs) were obtained in 23 dogs. Spinal cord ischemia was produced by cross-clamping the descending thoracic aorta just distal to the origin of the left subclavian artery through a left thoracotomy. Mean proximal aortic blood pressure was maintained between 90 and 100 mm Hg by partial exsanguination. Serial SEPs were obtained at 60-second intervals until the SEP disappeared. Aortic cross-clamping was continued for 10 additional minutes after the disappearance of the SEP. In Group 1 (N = 8), no medication was given when the aortic cross-clamp was removed. In Group 2 (N = 8), a bolus of 25,000 units of superoxide dismutase was injected into the proximal aorta prior to removal of the aortic cross-clamp, and was followed by 5,000 units per minute for 10 minutes after release of the cross-clamp. In Group 3 (N = 7), 50,000 units of superoxide dismutase was administered as a bolus prior to removal of the aortic cross-clamp, followed by an additional 10,000 units per minute for 10 minutes as in Group 2. The postoperative neurological status was assessed by Tarlov's criteria. There was no significant difference in aortic cross-clamp time among the three groups. Paraplegia developed in 4 animals in Group 1; the remaining 4 dogs had paraparesis. In Group 2, paraparesis developed in 2 of 8 dogs; the other 6 had no neurological injury. All the animals in Group 3 had complete recovery.(ABSTRACT TRUNCATED AT 250 WORDS)     

热休克蛋白60诱导小鼠皮肤移植耐受的实验研究

目的探讨热休克蛋白60（heat shock protein60，HSP60）对小鼠移植皮片成活的影响及其机制。方法选用60只C57BL／6（H．2b）小鼠为受体，45只BALB／C（H．2d）小鼠、15只CBA／N（H-2^k）为供体，均为8～12周龄近交系雌性小鼠。受体小鼠剪下1cm&#215;1cm全层皮肤，干纱布清创，即为植床：随机分为4组，每组15只。A组：无菌取供体BALB／C（H．2d）小鼠背部1cm&#215;1cm全层皮片，刮去皮下组织后移植至受体小鼠背部；B组：受体小鼠背部皮下注射0．1mL不完全弗氏佐剂（imcompleted Freund’s adjuvant，IFA），2周后行BALB／C（H-2d）小鼠皮肤移植：C组：受体小鼠背部皮下注射经0．1mLIFA乳化后的50gtgHSP60，2周后行BALB／C（H-2^d）小鼠皮肤移植：D组：受体小鼠背部皮下注射经0．1mL IFA乳化后的50μg HSP60，2周后行CBA／N（H-2^k）小鼠皮肤移植。B、C、D组供体皮肤移植方法同A组。术后观察移植皮片成活时间；移植术后7、25d行单向混合淋巴细胞反应及混合淋巴细胞培养上清液细胞因子检测；术后7d行迟发型超敏反应测定。结果A、B、C、D组移植皮片成活时间分别为（12．4&#177;0．5）、（11．6&#177;0.8）、（29.3&#177;2．6）及（27．6&#177;2．1）d：A、B组与C、D组比较，差异有统计学意义（P〈0．05），A、B组间及C、D组间比较，差异无统计学意义（P〉0．05）。皮肤移植术后7d，A、B、C、D组混合淋巴细胞反应每分钟放射脉冲数（counts of perminute impulse，cmp）值分别为12836&#177;1357、11876&#177;1265、6581&#177;573及6843&#177;612；A、B组与C、D组比较，差异有统计学意义（JP〈0．05）：A、B组间及C、D组间比较差异无统计学意义（JP〉0．05）；术后25d，各组cpm值分别为13286&#177;1498、12960&#177;1376、11936&#177;1265及12374&#177;1269，各组间差异无统计学意义（P〉0．05）。皮肤移植术后7d，C、D组混合淋巴细胞培养上清液IL-10高于A、B组，IL-2、干扰素γ（interferonl，，IFN-γ）低于A、B组（JP〈0．05），A、B组间及C、D组间差异均无统计学意义（JP〉0．05）：术后25d，各组IL-2、IL-10及IFN-γ差异无统计学意义（P〉0．05）。皮肤移植术后7d，A、B、C、D组受体小鼠对供体小鼠脾细胞的迟发型超敏反应为（0．84&#177;0．09）、（0.81&#177;0．07）、（0．43&#177;0．05）及（0．46&#177;0．03）mm：A、B组与C、D组比较，差异有统计学意义（P〈0．05），A、B组间及C、D组间差异无统计学意义（P〉0．05）。结论HSP60对免疫耐受的诱导和维持有一定作用。     

A Place in History: Paul Broca and Cerebral Localization

Neurologic deficits after the surgical repair of thoracic and thoracoabdominal aortic disease are devastating complications. Recently, pharmacologic preconditioning with potassium channel openers was reported to protect the spinal cord against neurologic injury in a model of spinal cord ischemia. A novel benzopyran derivative with an N-cyanoguanidine group, KR-31378, has been synthesized as a new therapeutic agent against ischemic injury. In the present study, we evaluated the protective effects of KR-31378 on spinal cord ischemic injury and compared its neuroprotective activities and hemodynamic stabilities with those of diazoxide. Thirty-four New Zealand white rabbits were randomly divided into four groups: ischemia group (n = 10, 25 min of aortic cross-clamping without any intervention), diazoxide group (n = 8, diazoxide [5 mg/kg] intravenously 15 min before the 25-min cross-clamping), KR20 group (n = 8, KR-31378 [20 mg/kg] intravenously 30 min before the 25-min cross-clamping), and the KR50 group (n = 8, KR-31378 [50 mg/kg] intravenously 30 min before the 25-min cross-clamping). Neurologic functions were evaluated for 72 h postoperatively using modified Tarlov's scores. All rabbits were sacrificed for histopathologic observations after finally scoring neurologic function. All rabbits but three survived. The rest were completely evaluated 72 h postoperatively. Unlike diazoxide-treated rabbits, KR-31378-treated rabbits showed relatively stable hemodynamics. Tarlov's score outcomes showed a marked improvement in the diazoxide group, in the KR20 group, and in the KR50 group compared to the ischemia group (p =. 005,. 002, and. 001, respectively). However, Tarlov's scores in the KR50 group were not significantly different from those of the diazoxide group. Histopathologic data were not significantly different between the groups, but the degree of degenerative change in motor neurons showed a significant correlation with Tarlov's scores 3 days postoperatively (γ = ?.378, p =. 036). Thus, the administration of KR-31378 before the aortic cross-clamping resulted in a significant improvement in neurologic outcome with stable hemodynamics in this rabbit model.     

The effects of cyclosporin A and insulin on ischemic spinal cord injury in rabbits

We examined the effects of cyclosporin A (CsA), a drug that inhibits mitochondrial permeability transition pore, and insulin on ischemic spinal cord damage in rabbits. We assigned rabbits to 5 groups (n = 6 in each); sham barrier-opened group (sham BO), barrier-opened group (BO), barrier-opened-CsA group (BO-CsA), barrier-opened-insulin group (BO-I), and barrier-opened-CsA-insulin group (BO-CsA-I). The blood-spinal cord barrier was opened to facilitate drug penetration by a mild injury to the lumber spinal cord on day 1. CsA (10 mg/kg per day IV) was administered on day 3 to day 5 (total 30 mg/kg). Insulin was administered 30 min before ischemia. In all groups, spinal cord ischemia was produced on day 5 by occluding the abdominal aorta for 13 min. Neurological and histopathological evaluations were performed 4 days after ischemia. In group BO-CsA, blood glucose concentrations were significantly larger compared with the other four groups, and no protection was observed. In contrast, hindlimb motor function in groups BO-I and Bo-CsA-I and histopathology in group BO-CsA-I were significantly better than in groups sham BO, BO, and BO-CsA. The results indicate that insulin protects against ischemic spinal cord injury, whereas the effect of CsA is, at best, minimal.