Chemically induced intestinal de-epithelialization using silver nitrate for bladder augmentation

The use of bowel segments for bladder augmentation has been associated with metabolic complications, infections, stones, and cancer at the vesicoenteric anastomosis. The establishment of a transitional epithelium over the de-epithelialized surface of a segment of intestine might alleviate these complications. In this study, chemical de-epithelialization and urothelial re-epithelialization were attempted using silver nitrate (AgNO₃) solutions at different concentrations. Augmentation cystoplasty was performed in 55 female Swiss-Albino rats using a 1.5-cm detubularized segment of sigmoid. Forty-one rats survived and were killed 12 weeks postoperatively. There were four groups, including one group of eight rats that underwent augmentation alone (group 1, control), while the other three groups were treated with 1 g/100 ml (11 rats), 5 g/100 ml (10 rats), and 10 g/100 ml (12 rats) AgNO₃ solutions, respectively, before augmentation. Histopathological analysis demonstrated almost complete de-epithelialization and urothelialization of the sigmoid segment treated with 10 g/100 ml AgNO₃ solution, which did not occur in the other groups. Postoperative bladder capacities were increased in all groups. There was no obvious histological difference in the level of collagen deposition and/or fibrosis in the augmented tissues in any of the experimental groups. We conclude that 10 g/100 ml AgNO₃ solution can be successfully used for chemical de-epithelialization and urothelial re-epithelialization of augmented intestinal segments, and are worthy of further investigation. Received: 23 March 2000 / Accepted: 11 September 2000     

无水乙醇和硝酸银处理兔肠黏膜效果的对比研究

目的:以兔为模型,观察比较无水乙醇和硝酸银溶液去肠黏膜的效果,为黏膜处理的试剂选择提供思路。方法:将25只白兔随机分为五组,每组5只,取20cm回肠段做隔离肠襻。五组分别以无水乙醇8min(A)、无水乙醇15min(B)、6%硝酸银8min(C)、3%硝酸银15min(D)、生理盐水8min(E)处理隔离之肠段。4周末,用葡萄糖吸收试验测定隔离肠袢吸收功能并取标本观察病理学改变。结果:无水乙醇和硝酸银溶液均具有去肠黏膜作用,四个处理组较对照组在形态学方面具有明显萎缩改变(P<0.01),葡萄糖吸收试验提示处理后肠段吸收功能减弱(P<0.05)。无水乙醇8min和6%硝酸银8min处理肠黏膜的效果好,对黏膜的吸收和分泌功能均有较好的抑制作用,但两组间比较差异无统计学意义(P>0.05)。结论:无水乙醇灌注8min和6%硝酸银灌注8min处理兔肠黏膜效果确切,能有效抑制吸收和分泌功能。两种方法处理后,在病理形态上未见明显差别,硝酸银在处理黏膜时与乙醇相比无明显优势。     

Long-term effects of extraluminal dilatation with a rigid circle on arteriovenous anastomotic line in venous grafts transposed into arterial defects

Postanastomotic narrowing resulting from subintimal hyperplasia is a well-known phenomenon. In the current study the authors compared a metallic circle and conventional suture technique in anastomoses performed in two ends of external jugular vein grafts interposed in carotid arteries of rabbits. They recorded the patency rates, fluid flow rates, and histological effects of the circle on the anastomotic line and compared them with conventional suture anastomoses. In 16 rabbits (experimental group) a standard suture was used in both ends of the jugular vein graft transposed to the carotid arteries on one side. On the other side, circle anastomoses were performed on both ends of the vein graft. In an additional 8 rabbits (control group), the anterior jugular veins and carotid arteries were dissected on both sides and left. During postoperative week 12, in 8 rabbits of the experimental group, the flow rates of carotid arteries were measured in vitro, and intraluminal silicone casts were prepared. In the remaining 8 experimental rabbits, carotid angiographies were performed and anastomotic segments were harvested for histological examination. Flow rates were also measured in the control group, and artery and vein segments were harvested. The patency rates of the vein grafts with metallic circle anastomoses were 100%, whereas conventional suture patency was 75% at week 12. Flow rates were significantly higher in the metallic circle-anastomosed vein grafts (74 ml per minute vs. 123 ml per minute, mean values; p < 0.05). Histological examination revealed reduced intimal thickness in the metallic circle anastomoses compared with conventional suture anastomoses. Dilatation of the arteriovenous end-to-end anastomotic line by a rigid circle prevents anastomotic narrowing in the long term.     

Studies on the Circulatory Pathophysiology of Trauma: I. Effect of Acute Soft Tissue Injury on Nutritional and Non-nutritional Shunt Flow Through the Hindleg of the Dog

Antigen induced arthritis (AIA) was elicited in 28 adult rabbits using ovalbumin. All animals developed an intensive monarthritis manifested by local heat and swelling. Two, 7 and 21 days later, respectively, 0.3 ml of 1 per cent OsO₄ was injected into the arthritic knees of three groups of 9 rabbits. The rabbits were killed 1, 3 and 6 months later. No modifying influence on the severe to complete cartilage destruction was evident. One group of 8 rabbits received only OsO₄ and the cartilage of these animals remained intact after 6 months.     

Effect of CO2 insufflation on bacteremia and bacterial translocation in an animal model of peritonitis

Background: The widespread adoption of the laparoscopic approach has created some concern over the potential for increased risk of bacteremia and sepsis due to increased intraabdominal pressure in patients with intraabdominal infection and peritonitis. This study examines the effect of the CO₂ pneumoperitoneum on bacteremia and bacterial translocation. Methods: New Zealand white rabbits were assigned into three groups of 10 animals. In group 1, 100 ml of sterile saline was infused into the peritoneal cavity under 10 mmHg CO₂ insufflation for 1 h. Group 2 received 100 ml of saline containing 10⁹ CFU/ml (colony-forming units) E. coli strain 0163 and 10 mmHg CO₂ insufflation for 1 h. Group 3 received an identical bacterial inoculum, followed by a 10-cm midline laparotomy. Blood samples were taken for culture by cardiac puncture at various intervals during the experiment. At 6 h after being subjected to the experimental procedures, the rabbits were killed and their organs were cultured quantitatively for translocating bacteria. Results: In group 1, neither blood nor organ cultures were positive, whereas in group 2 all blood cultures became positive in 1 h, and intraperitoneally infused bacteria translocated to the lung and kidney in all rabbits. In group 3, blood cultures became positive in 1 h, all but two of the rabbits had translocated bacteria in their lungs, and kidney samples from two of the rabbits were culture-positive. Conclusions: Our results indicate that both CO₂ pneumoperitoneum and laparotomy increase the incidence of bacterial translocation from the peritoneal cavity into the bloodstream. Thus, the risk of translocation to extraperitoneal organs such as lung and kidney is increased significantly by laparoscopy. Therefore, laparoscopic surgery should be avoided or used cautiously in the setting of acute peritonitis.     

关节腔内注射臭氧对骨关节炎软骨作用的实验研究

目的探讨医用臭氧直接在关节腔内注射对骨关节炎（OA）软骨的作用。方法32只新西兰兔随机均分为4组：正常对照组（N）、模型对照组（M）、低剂量臭氧组（L）和高剂量臭氧组（H）,每组8只。M、L、H三组分别于第1、4实验日经右膝关节腔内注射1．6％papain溶液0．3ml制备OA动物模型。成功建模1周后,L、H组右膝关节腔内注射浓度分别为20μg/ml和40μg/ml的医用臭氧2ml,每周两次,共4周。末次注射后1周处死全部实验兔,截取胫骨内侧平台做病理学观察并进行Mankin评分。结果M、L、H三组胫骨内侧平台软骨均出现骨关节软骨损害改变,L、H组损害比M组严重,而H组又比L组严重;Mankin评分从正常组－模型组－低剂量臭氧组－高剂量臭氧组逐步递增,组间差异有统计学意义（P〈0．01）。结论关节腔内反复注射臭氧后,对膝关节OA软骨产生了进一步损害的作用,损伤程度随臭氧浓度的增加而加重。     

Dosage and timing of Photofrin for photodynamic therapy of intimal hyperplasia

Photodynamic therapy has been recommended as a method of preventing intimal hyperplasia. The purpose of this study was to determine the dose and timing of Photoftin porfimer sodium needed to achieve a 3:1 or higher ratio between injured and control arteries after balloon endothelial injury. New Zealand White rabbits were anesthetized and their right femoral artery surgically exposed. A 4Fr Fogarty balloon catheter was passed retrograde into the lower abdominal aorta, inflated and pulled distally into the external iliac artery six times. All rabbits received heparin 100 IU/kg. Arteriotomies were closed and the animals recovered. Rabbits (n = 5 per group) were given intravenous Photofrin at a dose and time according to the following scheme: group I, 5.0mg/kg immediately after balloon injury; group II, 2.5mg/kg immediately after injury; group III, 5.0 mg/kg after 1 week; group IV, 5.0 mg/kg after 2 weeks; or group V, 2.5 mg/kg after 2 weeks. Animals were killed 24 h after drug administration and the aortoiliac segments removed for spectrophotofluorometric determination of Photofrin levels from injured and control segments. Mean(s.d.) ratios of injured: control arteries for groups I to V were 4.8 (2.6), 2.8 (1.2), 3.0 (1.0), 1.4 (0.3) and 1.0 (0.0) respectively. This ratio was significantly higher for group I rabbits compared with groups IV and V (P< 0.01, ANOVA). Fluorescence and light microscopy showed that Photofrin was localized primarily in the tunica media, and that the drug must be administered before significant intimal hyperplasia occurs. This study suggested that the Photofrin dose of 5 mg/kg given immediately or within 7-days of injury achieved at least a 3:1 ratio between injured to control arterial segments. Ratios based on this dose were significantly higher than those from rabbits who received Photofrin 2 weeks after endothelial injury.     

川芎嗪防治膝关节软骨退变的实验研究

目的 :应用膝关节制动的动物模型 ,探讨中药川芎嗪对膝关节OA软骨退变的保护作用。方法 :2 4只健康成年家兔 ,随机分为两组 ,每组 12只 ,动物的右后肢采用膝关节伸直位管形石膏制动的方法建立骨性关节炎模型。实验组膝关节注射川芎嗪 0 3ml,每周 1次 ,对照组注射 0 3ml生理盐水 ,每周 1次 ,在模型建立 6、9周时 ,每组分别取 6只动物 ,进行超氧化物歧化酶 (SOD)、丙二醛 (MDA)、糖胺多糖 (GAG)含量测定 ,并观察滑膜、软骨的病理改变。结果 :实验组MDA的浓度低于对照组的浓度 ,两者差异有显著性 (6周 ,P <0 0 5 ;9周 ,P <0 0 1) ,6周时 ,对照组的GAG含量明显上升 ,与正常组及实验组相比 ,均有显著性差异 (P <0 0 1)。实验组SOD浓度在不同时期均高于对照组 (6周 ,P <0 0 5 ;9周 ,P <0 0 1)。光镜观察可见 ,实验组滑膜和软骨病理改变较对照组轻。结论 :川芎嗪对早期膝关节OA的软骨退变具有保护作用     

A surgical model of composite cystoplasty with cultured urothelial cells: a controlled study of gross outcome and urothelial phenotype

OBJECTIVES: To study the outcome of composite cystoplasty using cultured urothelial cells combined with de-epithelialized colon or uterus in a porcine surgical model, using appropriate controls, and to characterize the neo-epithelium created by composite cystoplasty. MATERIALS AND METHODS: Urothelial cells were isolated and propagated in vitro from open bladder biopsies taken from nine female minipigs. Cohesive sheets of confluent urothelial cells were transferred to polyglactin carrier meshes and sutured to de-epithelialized autologous colon in four animals and de-epithelialized autologous uterus in five. These composite segments were then used for augmentation cystoplasty. Conventional colocystoplasty, de-epithelialized colocystoplasty and sham operations were carried out in six control animals. After killing the animals at approximately 90 days the bladders were removed for examination and immunohistochemical analysis, using a panel of antibodies against cytokeratins and urothelial differentiation-associated antigens. RESULTS: Macroscopically, the bladders augmented with composite segments derived from uterine muscle had no evidence of shrinkage or contracture. Histological analysis showed that in four of five composite uterocystoplasties, the neo-urothelium was stratified and had a transitional morphology, although in some areas coverage was incomplete. Immunohistochemical analysis showed evidence of squamous differentiation in both native and augmented segments. All composite and de-epithelialized colonic segments showed significant contraction with poor urothelial coverage, reflecting the unsuitability of the thin-walled porcine colon for de-epithelialization. CONCLUSIONS: The functional and macroscopic outcome of bladder augmentation with a composite derived from cultured urothelium and de-epithelialized smooth muscle of uterine origin endorses the feasibility of composite cystoplasty.     

Cement augmentation of lag screws: an investigation on biomechanical advantages

Background

In trauma surgery, lag screws are commonly used. However, in osteoporotic bone, anchorage can be considerably compromised. This study investigates the biomechanical potential of cement augmentation in terms of improved fixation.

Methods

36 Surrogate osteoporotic bone specimens were utilised in three biomechanical experiments, each comparing 6 augmented with 6 non-augmented samples. Standard partially-threaded lag screws (Synthes) were placed following surgical standard. For the augmented groups, 0.4 ml of polymethylmethacrylate was injected into the pre-drilled hole prior to screw placement. Interfragmentary compression was determined using a cannulated ring compression sensor. Maximum torque was recorded with a torque wrench. Compressive relaxation after 24 h, relaxation after loosening and re-tightening the screw as well as maximum compression and torque at failure were measured.

Findings

Mean relaxation was significantly lower for the augmented group (p < 0.01). After 24 h, a remaining fragmental compression of 62 % for the augmented and 52 % for the non-augmented specimens was found. Loosening and re-tightening of the screw did not affect the compressive relaxation when augmentation was applied (p = 0.529), compared to an increased relaxation after re-tightening in the non-augmented group (p = 0.04). The mean maximum compression and torque until failure were significantly higher for the augmented group (p < 0.001).

Interpretation

Cement augmentation of lag screws can improve fixation stability in terms of installing and maintaining interfragmentary compression. Effects of relaxation can be reduced and re-tightening of screws is possible without compromising the fixation. Particularly in reduced bone mass, augmentation of lag screws can markedly increase the security of the technique.     

The administration of folic acid improves erectile function and reduces intracavernosal oxidative stress in the diabetic rabbit

OBJECTIVE

To test the possibility that folic acid (FA) may be a means of treating erectile dysfunction (ED) in diabetes mellitus (DM), by studying the effect of FA administration to DM rabbits on cavernosal function and intrapenile oxidative stress.

MATERIALS AND METHODS

To investigate the effect of administering FA to DM rabbits on erectile function and oxidative stress the formation of superoxide (O₂^‐), 8‐isoprostane F_2α (8‐IPF_2α) and prostacyclin (as 6‐keto‐PGF_1α) were assessed, as well as carbachol‐ and electrical field stimulated (EFS) relaxation and p47^phox content (active component of NADPH oxidase complex). Non‐ketotic DM was induced in New Zealand rabbits with alloxan and FA administered orally daily for 1 month. Rabbits were killed, penises excised and segments prepared. These were mounted in an organ bath and relaxation elicited with carbachol or EFS. O₂^‐ release was measured spectrophotometrically, p47^phox expression by Western blotting and 8‐IPF_2α and 6‐keto‐PGF_1α formation by enzyme‐linked immunosorbant assay. Blood was collected for measurement of homocysteine, red blood cell (RBC) folate and glucose.

RESULTS

In cavernosal tissue from DM rabbits, carbachol‐and EFS‐induced relaxation was significantly impaired compared with the untreated controls. O₂^‐ release, p47^phox expression and 8‐IPF_2α formation were all enhanced and 6‐keto‐PGF_1α formation reduced compared with the controls. All these effects were reversed by FA. Plasma total homocysteine was reduced and RBC folate elevated.

CONCLUSIONS

The administration of FA may constitute a strategy for reducing ED in patients with DM.     

胸部硬膜外神经阻滞对高脂血症家兔冠状动脉粥样硬化形成的影响

目的 探讨胸部硬膜外神经阻滞（ＴＥＡ）对实验性高脂血症家兔冠状动脉粥样硬化形成的影响。方法 健康纯种新西兰雄兔２１只，随机分为三组，每组７只，对照组：普通饲料喂养；高脂组：普通饲料＋１．５ｇ胆固醇／ｄ；ＴＥＡ组：普通饲料＋１．５ｇ胆固醇／ｄ＋ＴＥＡ（０．１２５％布比卡因０．３ｍｌ，２次／日），实验前和实验第２、４、６、８周分别从耳中央动脉抽血２ｍｌ，测定血清中总胆固醇（ＴＣ）、甘油三脂（ＴＧ）、高密度脂蛋白（ＨＤＬ－Ｃ）、低密度脂蛋白（ＬＤＬ－Ｃ）的水平，实验第８周末，气栓法处死全部动物，立那开胸取出心脏，固定后在心室乳头肌水平横断心室，切片染色后，用ＢＨＥＣ显微微机图像处理系统测定横断面每根肌间小动脉截面的硬化程度。结果 实验前三组血清血脂水平无显著性差异（Ｐ〉０．０５）；与对照组比较，高脂组及ＴＥＡ组血清Ｔ     

骨质疏松山羊椎体骨水泥强化后对其相邻椎体生物力学的影响

目的 分析骨质疏松山羊椎体强化后对椎体刚度、应变及相邻椎体上下终板应力的影响,探讨椎体强化是否为相邻椎体骨折的潜在高危因素。方法 将12只骨质疏松山羊随机分为实验组和对照组,每组6只,实验组行L₁椎体强化术、术中以聚甲基丙烯酸甲酯(PMMA)骨水泥强化椎体,对照组不进行手术。术后1周取2组山羊T₁₂～L₃标本行生物力学测试。使用Aramis三维运动和变形测量系统获取轴向加压400 N时T₁₃、L₁、L₂椎体的应变,同时获得T₁₃、L₁、L₂椎体的相对位移,通过载荷-位移曲线获得T₁₃、L₁、L₂椎体的刚度。设定实验载荷为轴向400 N,分别检测T₁₃下终板及L₂上终板所受的应力。结果 实验组L₁应变比对照组降低、刚度比对照组增加,差异均有统计学意义(P<0...     

以藻酸钙为载体的可注射组织工程骨行隆鼻术的实验研究

目的：研究可注射组织工程骨做为隆鼻术植入材料的可行性。方法：从兔髂骨中获取骨髓基质成骨细胞，将骨髓基质成骨细胞与25g/L藻酸钠溶胶混合形成藻酸钠/骨髓基质成骨细胞复合物，取其2mL与0.17g硫酸钙粉末混合均匀，注射于新西兰兔鼻背部骨膜下，观察成骨情况。结果：藻酸钙/骨髓基质成骨细胞复合物植入兔鼻背部皮下4周后有类软骨样组织形成，8周时有骨小梁、骨髓腔等骨组织结构。结论：以藻酸钙为载体的可注射性组织工程骨可用于隆鼻术植入材料。     

Blocking of tumor necrosis factor activity promotes natural repair of osteochondral defects in rabbit knee

Background and purpose Osteochondral defects have a limited capacity for repair. We therefore investigated the effects of tumor necrosis factor (TNF) signal blockade by etanercept (human recombinant soluble TNF receptor) on the repair of osteochondral defects in rabbit knees.Material and methods Osteochondral defects (5 mm in diameter) were created in the femoral patellar groove in rabbits. Soon after the procedure, a first subcutaneous injection of etanercept was performed. This single injection or, alternatively, 4 injections in total (twice a week for 2 weeks) were given. Each of these 2 groups was divided further into 3 subgroups: a low-dose group (0.05 μg/kg), an intermediate-dose group (0.4 μ g/kg), and a high-dose group (1.6 μ g /kg) with 19 rabbits in each. As a control, 19 rabbits were injected with water alone. The rabbits in each subgroup were killed 4 weeks (6 rabbits), 8 weeks (6 rabbits), or 24 weeks (7 rabbits) after surgery and repair was assessed histologically.Results Histological examination revealed that the natural process of repair of the osteochondral defects was promoted by 4 subcutaneous injections of intermediate-dose etanercept and by 1 or 4 injections of high-dose etanercept at the various time points examined postoperatively (4, 8, and 24 weeks). Western blot showed that rabbit TNFα had a high affinity for etanercept.Interpretation Blocking of TNF by etanercept enabled repair of osteochondral defects in rabbit knee. Anti-TNF therapy could be a strategy for the use of tissue engineering for bone and cartilage repair.     

硫酸钙骨水泥强化骨质疏松绵羊腰椎的生物力学研究

目的评价硫酸钙骨水泥(CSC)强化骨质疏松绵羊腰椎力学强度的效果。方法成年雌性绵羊4只,行去势手术后饲养1年,测量去势前后腰椎骨密度。取L2～5共16个椎体,分为CSC组和对照组,每组8个椎体。CSC组经椎弓根向椎体内注射CSC(2.0 ml),对照组不给于任何处理。CSC组于术后12周测量L2～5单个椎体的骨密度,然后处死绵羊。取出椎体行压缩实验,测量各组中椎体的最大压缩应力(σult)和能量吸收值(EAV)。结果去势1年后绵羊腰椎骨密度显著下降,与去势前比较差异有统计学意义(P<0.05),骨质疏松绵羊模型建立成功。注射CSC 12周后椎体骨密度(BMD)、σult、EAV均高于对照组(P<0.05),且椎体的σult和EAV均与BMD成正相关关系(P<0.05)。结论 CSC可以提高骨质疏松椎体的BMD,强化骨质疏松椎体的力学强度,有利于避免或减少骨质疏松椎体骨折的风险。     

Predictive value of liver tissue flow in assessment of the viability of liver grafts after extended preservation in pigs

The crucial damage in cold storage of liver allografts is to the hepatic sinusoidal lining (microcirculation). Using different solutions, we studied whether determinations of graft tissue flow were valuable in estimating the viability of liver grafts. Twenty-three pairs of female pigs underwent orthotopic liver transplantation and were assigned to five groups according to the cold preservation time or solutions used: in group I the liver grafts were stored in Euro-Collins solution (EC) for 4 h (n = 3), in group II the grafts were stored in EC for 12 h (n = 5), in group HI the donor was pretreated with azathioprine (AZA), 1 mg/kg per day, orally (PO) for 3 days before harvesting and the graft was implanted after 12 h cold storage with EC (n = 6), in group IV the graft was stored in modified University of Wisconsin solution (mUW) for 4 h (n = 3), and in group V the graft was stored in mUW for 24 h (n = 6). Liver tissue blood flow (LTBF) was measured, using a laser doppler device, at 60 min after recirculation of the graft. In the case of EC preservation, LTBF (ml/100 g of liver tissue per min) correlated well with 4-day survival: 21.2 ± 3.0 ml/100 g of tissue per min mean ± SD, in group I (3/3, 100%); 10.0 ± 2.8 ml/100 g of tissue per min in group II (0/5, 0%); and 19.1 ± 3.4 m1/100 g of tissue per min in group III (5/6, 83.3%) (P < 0.05, group II vs I and III). All grafts with LTBF of more than 15 ml/100 g tissue per min functioned well. However, changes in microcirculation of the mUW-stored livers did not correlate with early function of the graft: 23.0 ± 2.3 m1/100 g of tissue per min in group IV (4-day survival; 3 of 3, 100%) and 23.5 ± 9.1 m1/100 g of tissue per min in group V (0 of 6, 0%). This was accompanied by graft dehydration during storage and an increased number of erythrocytes in the hepatic sinusoids post-recirculation. We concluded that assessment of liver tissue flow by LDF was very helpful and easy to apply in predicting liver graft failure in the case of preservation with Euro-Collins solution. However, LTBF should be carefully evaluated as a marker of liver graft viability when the liver graft is preserved with mUW.     

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.     

Ascorbic acid prevents cigarette smoke injury to endothelium-dependent arterial relaxation.

BACKGROUND: Arterial endothelium-dependent acetylcholine relaxation is impaired by smoking, and this injury may be mediated by oxygen free radicals. The purpose of this study was to examine the effect of ascorbic acid (AA) treatment on this injury. MATERIALS AND METHODS: New Zealand White rabbits (n = 6, each group) were placed in a 240-ft3 airflow chamber for 3 h per day, 5 days per week over an 8-week period. Animals were divided into four groups and fed rabbit chow and water or rabbit chow and AA (250 ml/kg)-supplemented water. The control-smoke rabbit group and the ascorbic acid-smoke rabbit group were exposed to mainstream cigarette smoke from a robotic smoke generator for the 3-h period, while the control-no smoke rabbit group and ascorbic acid-no smoke rabbit group were similarly placed in the chamber without smoke. At the end of 8 weeks, rabbits were sacrificed and segments of their superficial femoral arteries were suspended from tension transducers and the maximal contraction was determined. The remaining rings were contracted to 50% of the maximum and relaxation was determined by adding acetylcholine. Groups were compared using one-way ANOVA. RESULTS: Rings from control-smoke (5.13 +/- 0.21 g) and AA-smoke rabbits (6. 24 +/- 0.46 g) exhibited increased mean contraction to KCl (P < 0. 05) compared to control-no smoke rabbits (3.86 +/- 0.40 g). Acetylcholine-dependent relaxation was significantly reduced in the rings from the control-smoke rabbits compared to control-no smoke rabbits (acetylcholine, 5 x 10(-7) M: 24.7 +/- 2.7% versus 55.3 +/- 8.0%; acetylcholine, 7 x 10(-7) M: 27.5 +/- 2.3% versus 56.3 +/- 9. 2%). The AA-smoke group (acetylcholine, 5 x 10(-7) M: 61.8 +/- 12. 4%; 7 x 10(-7) M: 67.9 +/- 11.4%) had significantly increased relaxation compared to the control-smoke group (P < 0.05). There was no statistical difference in the mean percentage ring relaxation between the control-no smoke, AA-no smoke, and AA-smoke groups. CONCLUSIONS: Ascorbic acid protected the artery from cigarette smoke-induced endothelial injury.     

左旋多巴干预激素性股骨头坏死中骨细胞凋亡的实验研究

目的 探讨左旋多巴对激素性股骨头坏死中骨细胞凋亡的影响.方法 健康成年中国大耳白兔44只,随机分为三组.模型组,15只,经耳缘静脉注射10 μg/kg脂多糖,24 h后于右侧臀肌注射20mg/kg甲基泼尼松龙,共3次,每次间隔24 h.治疗组,15只,与模型组相同方法建模,注射完成后当日开始口服左旋多巴,剂量0.4 g·kg~(-1)·d~(-1).对照组,14只,于相同时间点注射等量生理盐水.制模后6、8周,各组分别处死7只,处死前行双髋关节X线摄片及MR检查,处死后取双侧股骨头标本,行HE染色并用TUNEL法测定细胞凋亡,观察组织病理学改变并进行细胞凋亡分析.制模后8周,采血测定3组兔子血清中胰岛素样生长因子-1(insulin-like growth factor-1,IGF-1)水平.结果 模型组X线片显示股骨头骨密度不均匀,可见有囊性变或硬化骨;HE染色显示骨小梁变细、稀疏、连续性中断,骨髓组织脂肪变性,空骨陷窝明显增多;TUNEL检测显示骨小梁内存在大量凋亡骨细胞.而治疗组X线片显示股骨头接近正常,骨密度均匀增高;组织病理学显示骨小梁连续性完整,制模后6、8周的空骨陷窝率分别为13.33‰±3.06‰及25.97‰±6.29‰,低于模型组的21.44‰±4.77‰及33.86‰±8.38%(P<0.01);骨细胞凋亡指数分别为74.93‰±14.32‰及120.67‰±13.13‰,低于模型组的102.56‰±18.96‰及202.02‰±18.99‰(P<0.01);制模后8周治疗组动物血清IGF-1含量为(14.78±2.37)ng/ml,高于模型组的(10.12±2.49)ng/ml(P<0.01);统计学分析显示模型组骨细胞凋亡指数与空骨陷窝率呈明显正相关(r=0.74,P<0.01).结论 左旋多巴可以减少激素诱导的骨细胞凋亡,减少股骨头坏死的发生.而左旋多巴通过体内代谢促进IGF-1的合成及释放可能是其预防及治疗激素性股骨头坏死的生物学途径之一.