兔心肌梗塞模型制备方法的改进及其在MRI中的应用

目的　对兔心肌缺血的模型制备方法进行改进 ,并探讨其在 MRI诊断研究中的价值。方法　分别采用高位结扎左冠状动脉前降支 (L AD)和同时低位结扎 L AD及左冠状动脉旋支 (L Cx)建立兔心肌梗塞模型 ,并在术后行 MRI检查 ,对取材后心肌标本行氯化三苯四氮唑 (TTC)及病理检查。结果　 1L AD组 2 0 % (5 / 2 5 )发生心室颤动导致死亡 ,L AD +L Cx组无一例发生室颤死亡。 2 L AD组 EKG改变明显者占 5 6 % (14 / 2 5 ) ,其中 2 1.4 3% (3/14 )在即刻就有 EKG明显改变 ,并在 30分钟后恢复正常 ;EKG改变不明显者占 4 4 % (11/ 2 5 ) ;L AD +L Cx组 10 0 %有 EKG明显改变 ,且 30分钟后亦无明显恢复。 3L AD组心肌梗塞范围较小 ,并均限于左室前壁 ,室间隔前部损害 ;而 L AD+L Cx组心肌梗塞范围较大 ,且累及左室前壁及侧壁 ,无一例有室间隔前部损害。4 L AD组中有 30 % (6 / 2 0 )不能显示小灶缺血局部心肌运动降低 ,16 .6 7% (3/ 18)无法分辨早期小梗塞灶的 MRI信号变化 ;而 L AD+L Cx组均能显示缺血局部心肌运动降低及梗塞灶早期的 MRI信号变化。结论　低位结扎兔心 L AD+L Cx,手术死亡率低 ,EKG改变明显 ,梗塞面积较大 ,是 MRI研究中一种较理想的心肌缺血动物模型制备方法。     

富血小板血浆治疗下肢慢性难愈合伤口47例随访研究

目的 探讨富血小板血浆(platelet-rich plasma,PRP)对下肢慢性难愈合伤口的修复作用. 方法 2007年5月-2007年11月,采用PRP注射治疗下肢慢性难愈合伤口47例.男41例,女6例;年龄15～68岁,平均43.2岁.原发疾病:胫腓骨骨折20例,跟骨骨折4例,跖骨骨折1例,下肢多发开放性骨折3例,胫骨骨髓炎10例,股骨骨髓炎1例,足踝部软组织损伤4例,截肢术后感染2例,足部矫形术后感染及跟腱修补术后感染各1例.外院治疗后2～4个月创口未愈合转入合并骨折未愈合23例,细菌培养结果 阳性38例.患者予2次清创加自体PRP伤口内注射,每次间隔2个月. 结果 患者均于首次注射PRP后获随访,随访时间4个月.首次注射PRP2个月后,34例伤口明显缩小,坏死组织及脓苔清除,组织色泽健康,血供良好,外露骨或肌肉组织被新牛肉芽组织覆盖.4个月随访时,无肌肉和骨组织外露患者,创面覆盖率79.3%4±18.O%,总治愈率29.8%.治疗前创口体积(11.8±5.6)mL,治疗后为(2.5±2.7)mL,创口体积缩小(9.3±4.9)mL,治疗前后创口体积比较差异有统计学意义(P＜0.05).术前23例合并骨折未愈合者,随访4个月时骨折完全愈合9例,骨痂生长明显增多12例,无明显改变2例,均无骨髓炎征象加重.细菌培养阳性结果 15例. 结论 PRP能有效促进软组织缺损修复,加速下肢慢性难愈合伤口愈合.     

Physical activity patterns in chronic hemodialysis patients: comparison of dialysis and nondialysis days.

OBJECTIVE: To determine physical activity patterns in chronic hemodialysis patients with a specific emphasis on the difference between dialysis and nondialysis days. Design A cross-sectional single-center study. SETTING: Vanderbilt University Outpatient Dialysis Unit. PATIENTS: Twenty current chronic hemodialysis patients: 10 male, 10 female; 15 black, 5 white; mean age, 50.1 +/- 9.9 years; height, 164.5 +/- 10.9 cm; weight, 82.5 +/- 15.4 kg; length on dialysis, 57.3 +/- 45.3 months. METHODS: Minute-by-minute physical activity was assessed over a 7-day period using a triaxial accelerometer, which consists of raw numbers or counts calculated by the 3 axes of the accelerometer (PA counts). PA counts were extrapolated on a daily and hourly basis. Physical functioning tests included: sit-to-stand, 6-minute walk, and 1-repetition maximal leg press exercise. Laboratory values for serum concentrations of albumin, prealbumin, C-reactive protein, and cholesterol were also collected. MAIN OUTCOME MEASURE: PA counts. RESULTS: Total PA counts were significantly lower on dialysis days when compared with nondialysis days (128,279 +/- 74,009 versus 168,744 +/- 95,168, respectively, P = .025). The average PA counts during the 4-hour dialysis time period were significantly lower on dialysis days when compared with nondialysis days (3,086 +/- 3,749 versus 11,070 +/- 7,695, respectively, P = .001). At postdialysis hours 1 and 2, PA counts on dialysis days were significantly higher than on nondialysis days (11,410 +/- 5,340 versus 9,082 +/- 6,646, P = .008, and 14,048 +/- 9,728 versus 8,662 +/- 6,433, P = .016, respectively). By postdialysis hour 4, PA counts on dialysis days had significantly decreased when compared with nondialysis days (6,068 +/- 6,268 versus 10,512 +/- 7,420 PA counts, P = .01, respectively). From postdialysis hours 5 to 20, there was no significant difference in PA counts between dialysis and nondialysis days. CONCLUSION: This study shows that physical activity is lower on dialysis days when compared with nondialysis days, and this decrease is caused by the lack of activity during the 4-hour hemodialysis procedure. New behavior modification strategies involving physical activity, both during hemodialysis and on nondialysis days, must be examined in this patient population.     

白血病病毒感染的SRSV/3T3细胞系DNA转化机制探讨

将SRSV/3T3细胞DNA转染NIH/3T3细胞,转染后17d,实验组出现18个集落,对照组出现4个集落。将实验组集落细胞接种于3只BALB/C裸鼠皮下,全部长成纤维肉瘤。将SRSV/3T3细胞DNA用EcoRI和BamHI酶切电泳,分别应用5种癌基因(v-myc、KJ-ras、v-src、v-sis和e-fos)作Southern印迹和分子杂交。发现SRSV/3T3细胞DNA的BamHI酶切片段与c-fos探针杂交后,在2.2～3.0 kb处出现阳性杂交带。应用c-fos单抗检测转化细胞,细胞核内呈阳性反应。表明SRSV/3T3细胞DNA含有fos样转化基因,在转化细胞内有此基因的过度表达。     

ISCHAEMIA-REPERFUSION INJURY TO THE INTESTINE

Ischaemia-reperfusion injury (IRI) is of obvious relevance in situations where there is an interruption of blood supply to the gut, as in vascular surgery, or in the construction of free intestinal grafts. It is now appreciated that IRI also underlies the gut dysfunction that occurs in early shock, sepsis, and trauma. The events that occur during IRI are complex. However, recent advances in cellular biology have started to unravel these underlying processes. The aim of this review is to provide an outline of current knowledge on the mechanisms and consequences of IRI. Initially, IRI appears to be mediated by reactive oxygen metabolites and, at a later stage, by the priming and activation of polymorphonuclear neutrophils (PMN). Ischaemia-reperfusion injury can diminish the barrier function of the gut, and can promote an increase in the leakage of molecules (intestinal permeability) or the passage of microbes across the wall of the bowel (bacterial trans-location). Ischaemia-reperfusion injury to the gut can result in the generation of molecules that may also harm distant tissues.     

Coronary vasomotion in patients with syndrome X: evaluation with positron emission tomography and parametric myocardial perfusion imaging

The aim of this study was to elucidate further the causative mechanism of abnormal coronary vasomotion in patients with syndrome X. In patients with syndrome X, defined as angina pectoris and documented myocardial ischaemia during stress testing with normal findings at coronary angiography, abnormal coronary vasomotion of either the micro- or the macrocirculation has been suggested as the causative mechanism. Accordingly, we evaluated endothelial function, vasodilator reserve, and perfusion heterogeneity in these patients. Twenty-five patients with syndrome X (definitely normal coronary arteriogram, group A), 15 patients with minimal coronary artery disease (group B) and 21 healthy volunteers underwent [¹³N]ammonia positron emission tomography at rest, during cold pressor stimulation (endothelial function) and during dipyridamole stress testing (vasodilator reserve). Heterogeneity of myocardial perfusion was analysed by parametric polar mapping using a 480-segment model. In both patient groups, resting perfusion was increased compared to the normal subjects: group A, 127±31 ml·min^–1·100 g^–1; group B, 124±30 ml·min^–1·100 g^–1 normal subjects, 105±21 ml·min^–1·100 g^–1 (groups A and B vs normals,P<0.05). These differences were abolished after correction for rate-pressure product. During cold pressor stimulation, the perfusion responses (ratio of cold pressor perfusion to resting perfusion) were similar among the patients and the control subjects (group A, 1.20±0.23; group B, 1.24±0.22; normal subjects, 1.23±0.14). Likewise, during dipyridamole stress testing, perfusion responses were similar among the three groups (group A, 2.71±0.67; group B, 2.77±1.29; normal subjects, 2.91±1.04). In group A the heterogeneity of resting perfusion, expressed as coefficient of variation, was significantly different from the volunteers (20.1±4.5 vs 17.0±3.0,P<0.05). In group B (coefficient of variation 19.4±3.9) the difference from normal volunteers was not significant. In this study, patients with syndrome X and patients with minimal coronary artery disease showed normal perfusion responses during cold pressor stimulation and dipyridamole stress testing. Our findings therefore suggest that endothelial dysfunction and impaired vasodilator reserve are of no major pathophysiological relevance in patients with syndrome X. Rather, other mechanisms such as increased sympathetic tone and focal release of vasoactive substances may play a role in the pathogenesis of syndrome X.     

Studies of the effects of dietary zinc on the immune organs and cellular immunity in the rat

ＳｔｕｄｉｅｓｏｆｔｈｅｅｆｆｅｃｔｓｏｆｄｉｅｔａｒｙｚｉｎｃｏｎｔｈｅｉｍｍｕｎｅｏｒｇａｎｓａｎｄｃｅｌｌｕｌａｒｉｍｍｕｎｉｔｙｉｎｔｈｅｒａｔＷｕＪｉａｈｕｉ（吴嘉惠）；ＷｕＳｈｕｉｂｉｎｇ（吴水冰）；ＢａｉＪｉａｓｉ（白家驷）；ＫｏｎｇＸ...     

乙肝病毒DNA阳性患儿家族成员的调查

本文对１４例ＨＢＶ－ＤＮＡ阳性患儿的家庭成员２３人进行血清学检测，并收集２２例正常人血清为对照组。２３例家庭成员中ＨＢＶ－ＤＮＡ阳性率为３４．８％（８／２３），明显高于对照组４．５％（１／２２），Ｐ＜０．０１。ＨＢＶ－ＤＮＡ阳性率在患儿的双亲为４０％（４／１０），而在其祖父母辈为３３．３３％（３／９），二者无显著差异（Ｐ＞０．０５）。提示乙肝病毒感染的家庭聚集性存在双亲或祖父母辈与患儿间的易感性相似。     

数字化校园构建之理论基础探讨

从总结数字化建设的实际出发,从建构主义教学理论、教育传播理论和管理科学理论三个方面,较为全面地论述了构建数字化校园的理论基础,并探讨了在数字化校园建设中如何应用理论来指导实际工作.