坐骨神经横断伤后远侧段组织的形态学及相关因子表达变化

目的:通过制备GFP小鼠和B6小鼠坐骨神经横断伤模型,应用免疫组化技术以及RealTime-PCR技术观察和分析周围神经损伤后远侧段组织的形态学及相关因子表达变化。方法:制备GFP小鼠坐骨神经横断伤模型,应用免疫组化技术分别染色S100蛋白以显示施万细胞,染色NF蛋白以显示轴突;结合GFP小鼠的自发荧光以及Hoechst核染观察横断伤后不同时间点远侧段组织的形态学变化。制备B6小鼠坐骨神经横断伤模型,应用RealTime-PCR技术检测横断伤后远侧段组织中相关营养因子BDNF、NGF、CNTF及抗凋亡因子Bcl-2 mRNA的表达变化。结果:坐骨神经横断伤后,远侧段施万细胞S100蛋白的表达第7天时达到高峰,第14天时下降,形成狭长细胞索带;第21～28天时仅少数细胞S100蛋白阳性。远侧段NF免疫组化产物于横断伤后第7天时断裂呈碎片状,第28天时碎片亦基本消失不见。远侧段非特异核染数目随损伤时间延长而增加。同时,在远侧段整个溃变过程中,神经基膜管结构仍然可见。坐骨神经横断伤后,BDNF mRNA表达第1～3周内逐渐上调,其中第3周时达到高峰(P<0.01),第4周时下降到与正常值相比无统计学意义的水平。NGF mRNA表达第1周时达到高峰(P<0.01),第2周时比第1周有小幅下降,但仍然具有统计学意义(P<0.01),第二周以后下降到与正常值相似的水平。CNTF mRNA表达则在损伤后第1周时下降了35%,第2周时继续下降到正常水平的42.7%,其下降均具有统计学意义(P<0.01),第3周时有所回升,第4周时下降到低点。Bcl-2 mRNA表达在损伤后第1周时下降,第2、3周时上升,第3周时达到高峰,并且上升具有统计学意义(P<0.01)。结论:坐骨神经横断伤后4周,远侧段神经组织中神经基膜管结构仍然存在。神经营养因子BDNF、NGF、CNTF mRNA的表达时相不同,提示其表达调控机制不同。Bcl-2 mRNA表达变化与施万细胞凋亡相关。     

戊型肝炎病毒感染与胰腺癌发病的相关性临床分析

目的：分析戊型肝炎病毒（HEV）感染与胰腺癌发病的相关性。方法：以12例HEV感染的胰腺癌患者（感染组）和47例非HEV感染的胰腺癌患者（非感染组）为研究对象,收集相关临床资料包括胰腺、肝脏的病理表现等,分析HEV感染的胰腺癌患者的临床特征,并且用HEVRNA直接测序技术对合并HEV感染的胰腺癌患者的胰腺组织进行HEV定位分析。结果：感染组合并肝癌、肝硬化的概率高于非感染组,感染组胰腺癌发病的平均年龄较非感染组提前8.5年,2例HEV感染的胰腺癌患者的胰腺组织中检测到HEVORF2片段。结论：HEV感染与胰腺癌发病存在相关性。     

Contractile response of different segments of the latissimus dorsi muscle to chronic stimulation

Objective: This study was planned to investigate if there is any difference in terms of the muscle force between the distal and proximal segments of the latissimus dorsi muscle.Subjects and Methods: An implantable mock circulation system was placed around the latissimus dorsi muscle. The wrapping procedure around the implantable mock circulation was performed by using two different latissimus dorsi muscle segments. In group 1, the very proximal and in group 2, very distal part of the latissimus dorsi were wrapped. The main differences is the blood supply to the distal part of the latissimus dorsi that was interrupted during dissection. During the stimulation period which lasted 120 minutes, the pressure developed in this system and adenosine triphosphate (ATP) levels were measured.Results: The stimulation at 20 Hz did not result in any change in pressure and metabolic data. When it was switched to 43 and 85 Hz, ATP levels decreased with a resultant drop in pressure in group 2. However ATP levels were 15.9±2.2 μmol/gr and 14.8±2.5 μmol/gr in group 1, 12.0±1.4 μmol/gr and 6.1±1.2 μmol/gr in group 2 at 43 and 85 Hz respectively (p<0.05) at the end of the 90 minutes. The pressures at the same time interval were 89±11 and 102±7 mmHg in group 1, 61±7 and 65±8 mmHg in group 2 (p<0.05).Conclusion: In this study, we demonstrated that changes in the distal segment of the latissimus dorsi muscle affects its performance in terms of metabolic and pressure changes during high frequency electrical stimulation at 43 and 85 Hz.     

Recovery of locomotion in the cat following spinal cord lesions

In most species, locomotor function beneath the level of a spinal cord lesion can be restored even if the cord is completely transected. This suggests that there is, within the spinal cord, an autonomous network of neurons capable of generating a locomotor pattern independently of supraspinal inputs. Recent studies suggest that several physiological and neurochemical changes have to occur in the neuronal networks located caudally to the lesion to allow the expression of spinal locomotion. Some evidence of this plasticity will be addressed in this review. In addition, original data on the functional organisation of the lumbar spinal cord will also be presented. Recent works in our lab show that segmental responsiveness of the spinal cord of the cat to locally micro-injected drugs in different lumbar segments, in combination with complete lesions at various level of the spinal cord, suggest a rostro-caudal organisation of spinal locomotor control. Moreover, the integrity of midlumbar segments seems to be crucial for the expression of spinal locomotion. These data suggest that the regions of critical importance for locomotion can be confined to a restricted portion of the spinal cord. Later, these midlumbar segments could be targeted by electrical stimulation or grafts to improve recovery of function. Understanding the changes in spinal cord neurophysiology and neurochemistry after a lesion is of critical importance to the improvement of treatments for locomotor rehabilitation in spinal-cord-injured patients.     

ANTERIOR ST SEGMENT DEPRESSION IN INFERIOR MYOCARDIAL INFARCTION: EFFECT ON COMPLICATIONS AND LONG-TERM SURVIVAL

Abstract The effect of anterior ST segment depression in inferior myocardial infarction on early complications and long-term prognosis was studied. A modification of the Minnesota Code was used for grading the extent of ST segment depression in leads V₂ to V₄ on the first hospital electrocardiogram. In 267 patients with acute inferior myocardial infarction, 107 had isoelectric anterior ST segments, 84 had minor ( 0.5 mm) depression, and 76 had major (> 0.5 mm) depression. Patients with anterior ST segment depression had higher serum enzyme levels, higher Norris coronary pronostic indices, and more frequent cardiac failure during the acute stages, but similar 28 day case fatality rate (11.1%) compared with patients without anterior ST segment depression (12.6%). In the subsequent four years total cardiac death rates were not significantly different and the pattern of survival was not influenced, but there was a higher fatal re-infarction rate in patients with major anterior ST segment depression. Thus, anterior ST segment depression in inferior myocardial infarction was associated with more severe infarction in the early phase but was not a reliable marker of high risk after recovery. Selection of patients for further investigation should not be based on this observation alone.     

Differential effects of proinsulin C-peptide fragments on Na +, K +-ATPase activity of renal tubule segments

Summary Proinsulin C-peptide has been shown to stimulate the activity of Na ⁺ K ⁺ ATPase of rat renal tubule segments. Thirty-six peptides and amino acids, corresponding to parts of the intact rat C-peptide and suitable controls were screened for capacity to stimulate Na ⁺, K ⁺-ATPase in an attempt to determine potential active sites in the C-peptide molecule. The carboxy-terminal tetra and penta peptides were found to elicit 92–103 % of the intact molecule's activity, and the remaining segment, des-(27–31) C-peptide, did not possess stimulatory activity. Peptides from the middle C-peptide segment, however, centering around a GGPEAG sequence, stimulated Na ⁺, K ⁺-ATPase activity (36–80 % of the intact molecule's effect) but this effect was not balanced by corresponding inactivity of other parts. Furthermore, it was paralleled by activity of a non-native dipeptide d-form. It is concluded that the latter effect and that of the middle segment may represent complex interactions other than the apparently specific effects of the C-terminal segment. [Diabetologia (1998) 41: 287–291] Received: 31 July 1997 and in revised form: 30 October 1997     

肌肉动力与断端显微位移的动态观察

目的：观察骨折愈合过程中不同时期肌力和位移的变化，探讨肌肉动力在骨折愈合中的作用。方法：采用肌力和位移传感器，测试夹板固定下兔胫骨干闭合骨折后的肌力与位移变化，计算机同步数据采集。结果：正常肌力5．04kg，伤后第一天肌力1．87kg，位移0．87mm；7天对肌力3．35kg，位移最大为1．02mm；14天对肌力接近正常5．01kg（P＞0．05）；21天对肌力恢复正常，位移下降至0．28mm；35天时位移仅为0．035mm，骨折愈合。结论：肌肉动力为骨折端提供间歇性生理应力为骨折愈合所必需，骨折愈合的最佳应力是该部生理状态下所承受的肌力。在功能活动时允许断端一定范围的纵向活动，能促进骨折愈合。     

Zinc Uptake in Five Sectors of the Rat Gastrointestinal Tract: Kinetic Study in the Whole Colon

Purpose. The uptake of zinc as acexamic acid salt in the rat gastrointestinal tract, using an in situ static technique, was studied. Our aim was to investigate an absorption window for zinc and the uptake kinetics in the colon. Methods. To detect selectivity phenomena in zinc absorption, buffered saline solutions of zinc (50 µg/ ml) were perfused in stomach, whole colon and three 33-cm fractions of the small intestine (proximal, middle and distal segments). To characterize zinc uptake kinetics in whole colon, five different zinc concentrations (5, 25, 50, 150 y 250 µg/ml) were assayed. Zinc secreted into the gastrointestinal tract during the experiments was deducted from the uptake. Results. Zinc secretion was characterized as an apparent zero-order process for all the studied segments (mean secretion rate = 0.10 ± 0.03 µg/(ml × min)). The stomach exhibited little ability to absorb zinc (apparent first order rate constant = 0.17 ± 0.07 h^–1), whereas the highest transport rates were found in the last two thirds of the small intestine and colon (first order constants: 0.66 ± 0.13 h^–1, 1.00 ± 0.06 h^–1,0.97 ± 0.14 h^–1, 0.96 ± 0.19h^–l for proximal, middle, distal and colon segments, respectively). Zinc uptake in the colon was characterized by means of a Michaelis-Menten and first-order combined kinetics, with the following parameters: Vm = 0.36 ± 0.02 µg/(ml × min), Km = 18.01 ± 0.40 µg/ ml and Ka = 0.40 ± 0.01 h^–l. Conclusions. Zinc is preferably absorbed in the middle and distal parts of the rat gastrointestinal tract. In the colon a saturable mechanism may be involved in apparent absorption.