Comparison of the mechanical performance of three types of external fixators: linear, circular and hybrid

Different configurations of the Monticelli-Spinelli and Ilizarov external fixation systems were tested to define their mechanical properties. In five configurations the external fixator consisted of rings with tensioned wires (circular), while in one configuration two pairs of the tensioned wires and their correspondent ring were replaced by threaded pins (hybrid). Testing was performed in axial compression, bending and torsion. The results were compared to the characteristics of a selected linear fixator group. Both the circular and the hybrid configurations were non-linear in compression. In bending, circular fixators had a similar pattern in both anteroposterior and oblique loading directions. The bending load-displacement pattern for the hybrid fixators was similar to the linear fixators, higher stiffness in the plane of the pins. Torsion was linear for both circular and hybrid fixators, as for the linear fixators. By combination of wires and pins (hybrid configuration), the mechanical behaviour had characteristics from both linear and circular fixators. It is concluded that the three studied groups own different mechanical performance and can be considered as different types of fixators. While it has been demonstrated that osteogenesis can be achieved independently of the mechanical behaviour of the fixator, this study supports the suggestion that some complications can be related to the mechanical behaviour of the fixator.     

全覆膜金属可回收支架在治疗食管顽固性良性狭窄中的应用价值

目的探讨全覆膜金属可回收支架治疗食管顽固性良性狭窄的安全性及疗效。方法回顾性分析行全覆膜金属可回收支架治疗的33例食管顽固性良性狭窄患者的临床资料,评价治疗的可行性、安全性及疗效。结果 33例患者共计放置可回收支架41支,其中8例患者行二次可回收支架置入,术后均有不同程度胸痛及异物感;术后并发支架移位11例(共计14支),移位发生率34.1%(14/41);其余22例患者(共计27支支架)均于术后4~8周顺利回收。术中及术后无明显出血、穿孔等并发症发生,无支架相关死亡病例。所有患者定期参加随访(12个月),其中12例成功解除梗阻,临床缓解率为36.4%(12/33)。结论全覆膜金属可回收支架用于治疗食管顽固性良性狭窄是安全可靠的,可使部分患者成功解除梗阻,但支架移位发生率高,有待于临床进一步研究解决。     

姜黄素对干热环境热射病大鼠肾损伤及细胞凋亡的影响

目的探讨姜黄素对干热环境热射病大鼠肾脏损伤的病理变化及细胞凋亡的影响。 方法SPF级成年健康雄性SD大鼠50只，在SPF级环境适应性饲养1周，按随机数字表法分为5组：常温对照组、干热对照组、姜黄素低浓度处理组(50 mg/kg)、姜黄素中浓度处理组(100 mg/kg)、姜黄素高浓度处理组(200 mg/kg)，每组10只。常温及干热对照组给予0.9%生理盐水灌胃，姜黄素组大鼠给予不同浓度姜黄素溶液灌胃，连续7 d。第8天除常温对照组外，其余4组大鼠均转移到模拟干热环境实验舱中。入舱实验的第150 min达到热射病状态，麻醉处死大鼠后留取尿液、肾组织进行分析，肾损伤分子-1(KIM-1)试剂盒检测尿液KIM-1水平变化，苏木精-伊红(HE)染色观察各组大鼠肾组织病理形态变化，进行肾损伤病理学评分，细胞凋亡缺口末端标记技术(TUNEL)检测细胞凋亡并计算凋亡率。 结果常温对照组尿液KIM-1水平、肾损伤病理学评分、肾组织细胞凋亡率分别为[(100.36±5.54)ng/L]、[(35.50±9.52)分]、[(0.55±0.04)%]；干热对照组大鼠各指标分别为[(1 060.57±75.50)ng/L]、[(710.67±74.60)分]、[(5.53±0.48)%]；姜黄素低浓度处理组各指标分别为[(945.73±48.07)ng/L]、[(701.67±64.84)分]、[(5.10±0.37)%]；姜黄素中浓度处理组各指标分别为[(639.17±44.71)ng/L]、[(365.00±34.06)分]、[(2.05±0.35)%]；姜黄素高浓度处理组各指标分别为[(592.67±34.29)ng/L]、[(289.00±35.08)分]、[(1.33±0.20)%]。各项指标水平在各组间比较，均差异有统计学意义(F＝373.70，203.16，289.81；均P<0.01)，干热对照组KIM-1水平和肾损伤病理学评分均明显高于常温对照组(t＝31.04，21.99；均P<0.01)。肾损伤病理学评分和肾组织细胞凋亡率在姜黄素低浓度组和干热对照组之间比较，均差异无统计学意义(t＝0.22，1.74；均P>0.05)，姜黄素中浓度处理组(t＝10.33，14.43)、高浓度处理组(t＝12.53，19.82)与干热对照组之间比较，均差异有统计学意义(均P<0.01)。 结论姜黄素预处理对干热环境热射病大鼠肾损伤具有一定的保护作用，可能通过阻断肾细胞凋亡通路发挥对肾脏损伤的保护作用。     

Lymphoproliferative response to synthetic V3 loop P18 peptide and HIV-1 envelope glycoprotein among individuals immunized with gp160 candidate vaccines

Because T-cell responses are critical for defense against viral infections, the synthetic P18 peptide (RIQRGPGRAFVTIGK) and active component of gp160 protein has previously been shown to induce cytotoxic and helper T-lymphocyte responses. In order to further define the T-helper cells, responses which are known to play a role in enhancing the immunological response to foreign antigen, we studied the response of individuals immunized with HIV gp160 candidate vaccines. We investigated the proliferative cellular response of peripheral blood mononuclear cells (PBMC) derived from individuals immunized with gp160 antigens in three different protocols. We found a PBMC proliferative response to synthetic P18 peptide in healthy immunized individuals induced by gp160 antigen with or without vaccinia virus. There was correlation between the proliferative response to P18 peptide and other antigens such as HIV-like proteins and gp160 molecule. HLA-DR typing revealed the possible presentation of P18 peptide by several different class II molecules. Since these class II molecules occur frequently in the general population, P18 peptide appears to contain broadly reactive epitopes and thus is presented by mutiple HLA class II molecules. Due to its broad reactivity P18 peptide is one of the candidates for inclusion as a subunit vaccine against HIV-1.     

N0tchl、N0tch2表达与移行细胞肿瘤恶变及发展关系的研究

目的研究Notch通路相关基因蛋白Notchl、Notch2在移行细胞肿瘤恶变中的作用。方法利用免疫组化SP法对比检测Notchl、Notch2在移行上皮乳头状瘤、具有恶性潜能的乳头状瘤、低级别尿路上皮癌、高级别尿路上皮癌各30例中的表达,并与其临床病理参数进行对比研究。结果各个级别肿瘤中均存在Notchl、Notch2的表达;Notchl在移行上皮乳头状瘤、具有恶性潜能的乳头状瘤、低级别尿路上皮癌、高级别尿路上皮癌中的阳性表达率呈现下降趋势,其阳性表达率随病变级别升高而明显降低;其表达水平与病变程度间存在明显负相关（r=-0．6791,P=0．0021）。Notch2在移行上皮乳头状瘤、具有恶性潜能的乳头状瘤、低级别尿路上皮癌、高级别尿路上皮癌中的阳性表达率呈现上升趋势,其阳性表达率随病变级别升高而明显增加;其表达水平与病变程度间存在明显正相关（r=0．6612,P=0．0001）。Notchl在尿路上皮癌中表达水平与组织学类型、浸润深度、淋巴结转移密切负相关（P〈O．05）,与肿瘤体积、TNM分期无关（P〉O．05）;Notch2表达水平与肿瘤体积、组织学类型密切相关（P〈O．05）,与淋巴结转移、TNM分期、浸润深度无关（P〉O．05）。Notchl和Notch2在移行细胞肿瘤不同病变中的表达水平的相关性分析显示：两者表达存在明显负相关（r=-0．6608,P〈0．05）。结论Notchl、Notch2介导的上皮间质转换参与移行细胞肿瘤恶变,同时两者在移行上皮癌变中发挥协同作用,与肿瘤发展密切相关。     

Acute pericarditis

There are many causes of acute pericarditis (inflammation of the pericardium) and diagnosis is often difficult owing to the dynamic nature of the disease. History and physical examination, augmented by radiographic and ECG studies, will allow the diagnosis to be made in the majority of cases. The ECG typically undergoes a four-stage evolution, and frequent reassessment of the patient is essential. Outpatient treatment is usually successful, although a subgroup of these patients require hospitalization.     

Évaluation médico-économique du baclofène intrathécal chez les patients présentant une spasticité chronique sévère

A medicoeconomic evaluation of continuous intrathecal baclofen (Lioresal^®) infusion for symptomatic treatment of severe spinal spasticity was realised using a monocentric, comparative, retrospective approach where subjects were their own controls (n = 22). Study results confirm the efficacy of baclofen on symptoms, functional status of patients and on a non specific quality of life scale. Conversely, use of baclofen lead to a 67% increase of average annual costs of care for these patients and reaches around 173,500 French francs (~29,000 US$)/year. Such a cost seems to be acceptable with respect to clinical benefits. © 1998 Elsevier, Paris     

实时三维超声心动图容积-时间曲线测定冠心病患者左室峰值排空率的价值

目的探讨实时三维超声心动图（TR-3DE）容积-时间曲线（VTC）测定冠心病患者左室峰值排空率（PER）的应用价值。方法应用TR-3DE的左室VTC测量34例冠心病患者和34例正常人的PER,并进行比较;分析冠心病患者左室PER与射血分数（EF）的相关性。结果冠心病患者的PER明显小于正常对照组（P〈O．001）．与EF呈显著正相关（r=0．875）。结论TR-3DE VTC可以准确测量左室PER。能反映冠心病患者左室整体收缩功能状况。     

Quantitative measurements of second harmonic Doppler using ultrasound contrast agents

Quantitative measurements of second harmonic and first harmonic Doppler were carried out using two ultrasound contrast agents, Albunex^® and FS069. The RMS amplitudes of the Doppler shift spectra were measured as a function of the concentration of the agents, frequency and transmitted acoustic pressure. The results showed that, for a given lot of contrast agent investigated, FS069 was able to produce higher levels of first and, especially, second harmonic signals compared to Albunex. Under the same experimental conditions, the RMS Doppler amplitude (RDA) of FS069 was 3.8 ± 0.8 dB higher than Albunex at first harmonic and 12.6 ± 0.8 dB higher at second harmonic. The ratio of the second harmonic to first harmonic RDA, which we called R₂/R₁, decreases at a rate of 7 dB/MHz for both agents with increasing frequency. The difference in the value of R₂/R₁ between FS069 and Albunex at any frequency was approximately 4.5 dB. R₂/R₁ was found to increase linearly as a function of the transmitted acoustic pressure for both agents. Simulations using the Rayleigh-Plesset equation show a decrease of R₂/R₁ at a rate of 5 dB/MHz. Comparison of experimental results with theory indicates that the shell elasticity parameter may be an increasing function of the mean diameter of the bubbles.