Influence of extracellur Ca2+ on endogenous Cl− channels in Xenopus oocytes

Removal of Ca²⁺ from the external bath solution evoked marked depolarization and large currents (up to several microamperes) in voltage-clamped defolliculated oocytes of Xenopus laevis. The resulting current was not carried by a cation influx but was due to a huge Cl^– efflux, which could be strongly inhibited by the Cl^– channel blockers flufenamic acid and niflumic acid. Removal of Mg²⁺ or Ba²⁺ from the solutions had the same effects as removing Ca²⁺. The reversal potential of –12 mV also indicated that Cl^– channels were responsible for the large currents. Patch-clamp studies revealed a single-channel slope conductance of 90 pS. During oocyte maturation these channels remained active. The half-maximal Ca²⁺ concentration of about 20 M showed that quite low doses of extracellular Ca²⁺ profoundly influence the electrical properties of the oocyte membrane.     

体外反搏对血液流变性和血小板聚集性的影响

观察４０例心脑血管疾病患者体外反搏前后血液流变性和血小板聚集性变化。结果表明，反搏后全血比及还原比粘度、血浆粘度有不同程度的下降（Ｐ＜０．０５～０．０１）。反搏治疗后，１～５ｍｉｎ血小板聚集率、最大聚集率和最大聚集速度较反搏前均明显降低（Ｐ＜０．０５～０．０１），而５ｍｉｎ解聚率则明显增加（Ｐ＜０．０５）。提示体外反搏治疗不仅影响血液动力学，而且明显降低血液粘度，对血小板聚集功能有明显抑制作用。     

外固定架治疗桡骨远端粉碎性骨折

目的总结桡骨远端粉碎性骨折的外固定架治疗疗效。方法从1995年～2003年采用外固定架治疗桡骨远端粉碎性骨折46例,并进行随访。结果治疗后均随访1年,术后按Dienst评分,优良率为83．3％。结论外固定架固定牢靠,可早期活动腕关节,是治疗桡骨远端粉碎性、开放性骨折的有效方法。     

Caffeine and histamine-induced oscillations of K(Ca) current in single smooth muscle cells of rabbit cerebral artery

In the present experiment, we characterized the intracellular Ca²⁺ oscillations induced by caffeine (1 mM) or histamine (1–3 M) in voltage-clamped single smooth muscle cells of rabbit cerebral (basilar) artery. Superfusion of caffeine or histamine induced periodic oscillations of large whole-cell K⁺ current with fairly uniform amplitudes and intervals. The oscillatory K⁺ current was abolished by inclusion of ethylenebis(oxonitrilo)tetraacetate (EGTA, 5 mM) in the pipette solution. Caffeine- and histamine-induced periodic activation of the large-conductance Ca²⁺-activated K⁺ [K_(Ca)] channel was recorded in the cell-attached patch mode. These results suggest that the oscillations of K⁺ current are carried by the K_(Ca) channel and reflect the oscillations of intracellular Ca²⁺ concentration ([Ca²⁺]_i). Ryanodine (1–10 M) abolished both caffeine- and histamine-induced oscillations. Caffeine- induced oscillations were abolished by the sarcoplasmic reticulum Ca²⁺-adenosine 5-triphosphatase (Ca²⁺-ATPase) inhibitor, cyclopiazonic acid (10 M), and a high concentration of caffeine (10 mM). Inclusion of heparin (3 mg/ml) in the pipette solution blocked histamine-induced oscillations, but did not block caffeine-induced oscillations. By the removal of extracellular Ca²⁺, but not by the addition of verapamil and Cd²⁺, the caffeine-induced oscillations were abolished. Increasing Ca²⁺ influx rate increased the frequencies of caffeine-induced oscillations. Spontaneous oscillations were also observed in cells that were not superfused with agonists, and had similar characteristics to the caffeine-induced oscillations. From the above results, it is concluded, that in smooth muscle cells of the rabbit cerebral (basilar) artery, ryanodine-sensitive Ca²⁺-induced Ca²⁺ release pools play key roles in the generation of caffeine- and histamine-induced intracellular Ca²⁺ oscillations.     

人工补片无张力疝修补术59例临床分析

目的：探讨人工补片无张力疝修补术的疗效和优点。方法：对59例71个腹外疝在疝囊高位结扎后行人工补片无张力修补术的临床效果进行回顾性分析。结果：本组51例63个腹股沟疝和股疝的手术时间为30—80min，平均55min。术后切口均一期愈合，无切口感染、硬结、异物反应等并发症；术后并发短暂尿潴留2例；阴囊血肿2例、积液4例5侧。腹股沟疝术后5～7天(平均6天)出院，切口疝术后8-11天(平均9天)出院。随访5—51个月，复发2例。结论：人工补片无张力疝修补术是一种简单、安全、痛苦小、恢复快、效果好的疝修补方法，适用于腹壁缺损不严重的各种腹外侧及复发疝。     

Source of the slippage in the universal joints of the Hoffmann external fixator

An investigation was conducted to determine what improvements in the resistance to slippage could be obtained in selected interfaces (rod/clip torsional, cheek/bowl and cheek/clip) of the Hoffmann external fixator. The modification involved changing the standard wing-nut clamp for a bolt with a thread of 7 mm and a 1 mm pitch and placing an FAG 28–303 thrust-bearing (needle roller and cage assembly) between the bolt and the cheek. The results showed a significant improvement in the slippage values of all interfaces; increases of approximately six times were obtained at all torque values of the wing-nut clamp or fastener tested. Such improvements would markedly increase the reliability of external fixation systems and thus reduce the incidence of loss-of-reduction of fracture due to slippage of the universal joint.     

Cardio-respiratory adjustments and cost of locomotion in school children during backpack walking (the Italian Backpack Study)

The use of a school backpack is one of the possible causes of back pain in children. Oxygen consumption ( ), pulmonary ventilation, and heart rate (f _c) were measured in 35 pre-pubertal subjects [17 girls and 18 boys, mean (SD) age 11.3 (0.6) years]. They took part in a four-step experiment: (1) standing for 5 min, (2) walking at 3 km·h^–1 for 7 min, (3) walking at 3 km·h^–1 for 7 min carrying a school backpack weighing 8 kg, and (4) walking at 7 km·h^–1 for 5 min with no load. The occurrence of back pain in the last 2–3 years and during the last 15 days was assessed for the subjects by means of a questionnaire. Mean (SD) standing was 215 (45) ml^.min^–1 during walking at 3 km·h^–1, 503 (101) ml^.min^–1 during walking without a load, and increased to 541 (98) ml^.min^–1 during walking with a load (P<0.01). Carrying a backpack increased f _c only minimally. The energy cost of walking at 3 km^.h^–1 without the backpack was 10.0 (2.0) ml O₂ ^.m^–1, and with the backpack was 10.8 (1.9) ml O₂ ^.m^–1 (P<0.01). The net energy cost of locomotion was 0.129 (0.032) ml^.kg body mass^–1.m^–1 for the unloaded condition and slightly lower, at 0.123 (0.025) ml^.kg body mass^–1.m^–1 during loaded walking (P<0.05). Ventilation did not change significantly between unloaded and loaded conditions. When the data were assessed according to the occurrence of back pain, the f _c/ slope was significantly lower in children without back pain, even though the net energy cost of locomotion was similar. Overall, these data suggest that the cardiovascular effortrequired for locomotion while carrying a backpack is minimal. However, fatigability and back pain are more likely to take place in less physical performing subjects. Thus, the occurrence of back pain in schoolchildren during locomotion while carrying a backpack may improve with an improvement in their level of fitness. Electronic Publication     

Morphometric study of the ductus arteriosus during human development

During prenatal life, the ductus arteriosus connects the left pulmonary artery and the descending aorta. Morphometric features (length, external diameter, volume) of the ductus arteriosus in 131 human fetuses (65 males, 66 females) were studied by means of anatomical, digital and statistical methods. Regression analysis was used to investigate the growth of the ductus arteriosus during gestation. The values of the length of the ductus arteriosus ranged from 3.95 mm for the 15 week gestational group to 12.20 mm for the 34th week of gestation. The length of the ductus arteriosus related to fetal age (x) increased according to the linear function y = -3.0726 + 0.4381x. The mean values of the diameter of the ductus arteriosus ranged from 1.34 to 3.49mm for the 15 and 34 week gestational groups, respectively. The growth of the ductus arteriosus diameter followed in accordance with the linear function y = 0.2072 + 0.0935x. The mean values of the ductus arteriosus volume ranged from 5.08 mm3 for the 15 week group to 117.30 mm3 of the 34 week gestation group. The volume growth increased according to the function y = 0.0007x3.3782. Positive correlation coefficients between arterial parameters and fetal age were statistically significant (P < or = 0.01) and reached the following values: r1 = 0.98 for Length, r2 = 0.90 for diameter and r3 = 0.94 for volume. Despite the increase in absolute diameter, the relative diameter of the ductus arteriosus (ductus arteriosus-to-aortic bulb diameter ratio) decreased from 0.80 to 0.48.     

External fixation of unstable pelvic ring fractures: comparative rigidity of some current frame configurations

The effectiveness of external fixation in the stabilisation of pelvic ring fractures was studied in a laboratory cadaveric series. Shearing displacements occurring at sacroiliac joint and symphysis pubis dislocation sites, due to simplified longitudinal loading of the sacrum in an Instron unit, were monitored using variable-impedence transducers. The rigidity of fixation was compared for the Slätis and the Bonnel single anterior frames, for coupled and uncoupled double anterior frames, and for combined anterior-plus-posterior fixation achieved with separate transfixation pin clusters, with through-and-through pin clusters, or with a posterior screw plate. The data showed that the use of posterior fixation provided greatly enhanced stabilisation compared to that achieved with anterior fixation alone. The complex double anterior frames performed only slightly better than did the simpler single anterior frames. In no case, however, was it possible to recover rigidity levels approaching those of the intact pelvis. The results suggest that the transfixation pin arrangement is the most important determinant of pelvic fixation stability, and that further investigation of posterior screw-plate fixation is warranted.     

双关节骨外固定器在老年桡骨远端复杂性骨折治疗中的应用

目的：探讨双关节骨外固定器治疗桡骨远端复杂性骨折的效果。方法：对16例老年人桡骨远端复杂性骨折采用手法闭合复位、双关节骨外固定器固定进行治疗。结果：随访8～38个月，骨折均获得良好的复位与固定，疗效较满意。结论：手法复位，双关节外固定器治疗桡骨远端复杂性骨折，可有效矫正畸形，重建桡腕关节的稳定，是一种微创、安全、疗效确切的治疗方法。