Modulation of action potential duration by inhibition of the transient outward current in sheep cardiac Purkinje fibers

In sheep cardiac Purkinje fibers concentration-dependent inhibition of transient outward current (i_to) by 4-aminopyridine (4-AP, 3-1000 mol/l) was recorded with the two-microelectrode voltage-clamp technique, and correlated effects on action potential duration measured at — 70 mV (APD-70) were investigatigated.Half-maximal inhibition of i_to-amplitude occurred at 15 mol/l 4-AP. The drug exhibited no major effect on voltage-dependent control of inactivation but reduced the maximally available i_to-current. At different activation frequencies (0.05 Hz, 0.25 Hz, 1 Hz) an equal amount of i_to-current, measured as percentage of the respective control, was inhibited by 4-AP. The APD-70 was on the average increased by 4-AP (3–500 mol/l) in a concentration-dependont manner up to 151 % of control. The drug-induced prolongation, measured as percentage of the respective control, was independent of stimulation frequency (0.05 Hz, 0.25 Hz, 1 Hz). Prolongation of APD-70 was on the average more pronounced for short action potentials (APD-70<150 ms: 169 % of reference) than for longer ones (APD-70 150–300 ms: prolongation to 117 % of reference; 500 mol/l 4-AP; 0.25 Hz stimulation rate). Few long control signals (APD-70 >300 ms) were shortened by 4-AP. These results indicate that inhibition of i_to-current by appropriate drugs will result in a reduction of inhomogeneity of action potential duration.     

The anterolateral funiculus in the spinal cord in amyotrophic lateral sclerosis

We carried out a morphometric study on the myelinated fibers in the anterolateral funiculus (ALF) and lateral corticospinal tract (LCS) in the cervical segment of the spinal cord of 13 patients with classic amyotrophic lateral sclerosis (ALS), 6 of whom had been on a respirator: 5 age-matched subjects were used as controls. The results obtained revealed that: (1) the fiber-size distributions of the myelinated fibers in the ALF and LCS of the control subjects had peaks at 2 m; (2) there were marked and significant losses of large myelinated fibers in the ALF and LCS of ALS patients; (3) the patients who required respirator support showed more severe degeneration in the ALF than those who required none; and (4) the degree of myelinated fiber loss in the LCS did not correlate with either the illness duration or the history of respirator use.     

光猝灭法测定水杨酸醑中的水杨酸

目的：探索一种新的测定水杨酸醑中水杨酸的方法。方法：采用光猝灭法测定水杨酸醑中的水杨酸。结果：水杨酸浓度在 １～４０ μｇ／ｍ ｌ 范围内与 ｌｇ（ Ｆ０／ Ｆ）成线性,检测限为 １０ μｇ／ｍ ｌ,回收率为 １０２％ , Ｒ Ｓ Ｄ 为７８５％ ,与紫外分光光度法比较没有显著性差异（ Ｐ＞ ０．０５）。结论：本实验为在位、在线测定水杨酸奠定了基础。     

湿法纺制PEI／PES中空纤维气体分离共混膜

采用湿法纺丝工艺纺制了聚醚酰亚胺（ＰＥＩ）－聚苯醚砜（ＰＥＳ）中空纤维Ｈ２－Ｎ２和Ｈｅ－Ｎ２分离共混膜,得到Ｈ２和Ｈｅ的渗透通量及选择性为：ＪＨ２＝３６０ＧＰＵ,αＨ２／Ｎ２＝１６２,ＪＨｅ＝１８１ＧＰＵ,αＨｅ／Ｎ２＝７６．７;研究了芯液组成及其流量对膜性能的影响。通过扫描电镜,分析了中空纤维膜的结构,讨论了膜制备过程中的相转化原理。     

外源性雄激素对幼年大鼠骨骼肌肌纤维及其运动终板形态的影响

目的：观察雄激素对骨骼肌肌纤维及其运动终板形态的影响。材料与方法：给５ ｄ 龄的Ｗｉｓｔａｒ 雄性大鼠持续５ 周肌内注射丙酸睾丸酮（每天４０ｍｇ／ｋｇ）,用肌球蛋白ＡＴＰ酶染色法（ｐＨ１０－４ 孵育液预处理） 和乙酰胆碱酯酶染色法分别对大鼠趾长伸肌的肌纤维和运动终板染色。结果：雄激素对幼年雄性大鼠趾长伸肌的肌纤维类型形态以及运动终板的结构均没有显著影响（Ｐ＞０－０５）。结论：从形态上可能说明雄激素对肢体骨骼肌的收缩速度没有显著影响。     

某些血、尿生化指标与妇女骨密度的关系

目的探讨某些血尿生化指标与健康妇女骨密度的关系。方法用单光子骨密度仪测定妇女非优势侧前臂桡骨远端1／10处及中下1／3处骨密度,并测定了空腹10小时后的清晨2小时尿钙（Ca）、尿羟脯氨酸（Hyp）,尿肌酐（Cr）及血清碱性磷酸酶（AKP）含量。结果血清AKP、尿Hyp／Cr随增龄而增加,绝经后更明显,且均与骨密度呈明显负相关。尿Ca／Cr亦随增龄而增加,绝经后更为明显,但与骨密度无明显相关。结论血清AKP、空腹尿Hyp／Cr可作为反映骨转换状态的指标。     

Efficiency of Superfine Glass Fiber Membrane\= Filters for Depleting Leukocytes

ＩｎｔｒｏｄｕｃｔｉｏｎＩｎｔｈｅｄｏｎｏｒｂｌｏｏｄｃｏｌｅｃｔｅｄｂｙｂｌｏｏｄｃｅｎ－ｔｅｒｓ,ｌｅｕｋｏｃｙｔｅｓｈａｖｅｎｏｔｈｅｒａｐｅｕｔｉｃｆｕｎｃｔｉｏｎｔｏｐａｔｉｅｎｔｓｂｕｔｍａｙｉｎｄｕｃｅｍａｎｙｓｉｄｅｅｆｅｃｔｓ．Ｃｏ...     

应用视神经纤维分析仪检测正常人视网膜神经纤维层厚度

目的 探讨正常人的视网膜神经纤维层厚度及其象限比值与年龄的关系。方法 应用视神经每人义检测１９８例（１９８只眼）正常志愿者,并按年龄分组进行统计分析。结果 ＲＮＦＬＴ与年龄成负相关,上、下方象限厚度较鼻、颞侧大,与年龄相关、鼻、颞侧无此特点。上、下方象限厚度比值平均为１．０４１。结论 ＮＦＡ是测量ＲＮＦＬＴ的可靠方法,正常人的ＲＮＦＬＴ随年龄的增长而减少。