Muscle fluorometry: A determination of the depth of penetration

Summary Fluorometric recordings of NADH (nicotinamide adenine dinucleotide) were made on rabbit papillary muscles. The specimens were placed between the UV light source and a small window of the detection stage. As the muscle was moved over the window in a transverse direction, simultaneous measurement could be taken of transmitted UV light and fluorescent light for various thicknesses of tissue. It is concluded that a muscle thinckness of 0.65 mm, is optimal before absorption of the incident light decreases the fluorescence signal.     

Integrins and cardiovascular disease

Cardiovascular diseases involve abnormal cell-cell interactions leading to the development of atherosclerotic plaque, which when ruptured causes massive platelet activation and thrombus formation. Parts of a loose thrombus may detach to form an embolus, blocking circulation at a more distant point. The integrins are a family of adhesive cell receptors interacting with adhesive proteins or with counterreceptors on other cells. There is now solid evidence that the major integrin on platelets, the fibrinogen receptor α _IIb  β ₃ , has an important role in several aspects of cardiovascular diseases and that its regulated inhibition leads to a reduction in incidence and mortality due to these disorders. The development of α _IIb  β ₃ inhibitors is an important strategy of many pharmaceutical companies which foresee a large market for the treatment of acute conditions in surgery, the symptoms of chronic conditions and, it is hoped, maybe even the successful prophylaxis of these conditions. Although all the associated problems have not been solved, the undoubted improvements in patient care resulting from the first of these treatments in the clinic have stimulated further research on the role of integrins on other vascular cells in these processes and in the search for new inhibitors. Both the development of specific inhibitors and of mice with specific integrin subunit genes ablated have contributed to a better understanding of the function of integrins in development of the cardiovascular system.     

关于快慢两种肌纤维的形态结构及代谢特性与运动能力的研究

本文从形态结构及生理代谢角度论述了人体骨骼肌中的快慢两种肌纤维的生理机制及运动能力，并揭示出了用不同强度的练习可分别发展不同类型的肌纤维，同时也为运动员的选材提供了可靠的科学依据。     

Intercellular dye-coupling in intestinal smooth muscle. Are gap junctions required for intercellular coupling?

Summary The dye Lucifer Yellow was injected into single smooth muscle cells in the guinea pig small intestine in order to study intercellular coupling. Dye-coupling was observed in both the circular and longitudinal muscle layers and was markedly reduced when the intercellular pH was lowered. These results suggest the presence of gap junctions among intestinal muscle cells, but are inconsistent with previous ultrastructural studies that failed to demonstrate such junctions in the longitudinal muscle.     

幼儿体操教学对幼儿大肌肉动作发展影响的实验研究

采用大肌肉动作发展测试量表,研究了幼儿体操教学对4～6岁幼儿大肌肉群动作发展的影响,结果表明：幼儿体操教学可以有效地促进4～6岁幼儿的大肌肉群动作的发展,且对位移技能的影响较为显著;4～6岁幼儿大肌肉动作的发展具有不平衡性,男女孩位移动作方面发展较均衡,而男孩物体控制方面较好。     

化橘红中主要活性成分对豚鼠气管平滑肌细胞增殖的影响

目的：初步观察化橘红中主要活性成分对豚鼠气管平滑肌细胞增殖的影响。方法通过原代培养豚鼠气管平滑肌细胞,采用 MTT 法观察化橘红中主要活性成分柚皮苷（Naringin）、橘皮内酯（Meranzin）和水合橘皮内酯（Meranzin hydrate）对细胞增殖的影响。结果柚皮苷（0.2~2.0 mg/mL）对豚鼠气管平滑肌细胞增殖有明显的促进作用（P<0.01）,水合橘皮内酯（0.1~1.0 mg/mL）对豚鼠气管平滑肌细胞增殖有明显的抑制作用（P<0.01）,橘皮内酯（0.05~0.5 mg/mL）对豚鼠气管平滑肌细胞的增殖作用不明显（P ＞0.05）。结论柚皮苷与水合橘皮内酯可能是化橘红主要药效活性成分。     

Mechanical and biochemical characterization of the contraction elicited by a calcium-independent myosin light chain kinase in chemically skinned smooth muscle

Summary The contraction induced by a Ca²⁺-independent myosin light chain kinase (MLCK-) was characterized in terms of isometric force (F_o), immediate elastic recoil (SE), unloaded shortening velocity (V_us), shortening under a constant load and ATPase activity of chemically skinned smooth muscle preparations. These parameters were compared to those measured in a Ca²⁺-induced contraction to assess the nature of cross bridge interaction in the MLCK-induced contraction. F_o developed in chicken gizzard fibers as well as SE were similar in contractions elicited by either agent. V_us in the contraction induced by MLCK-(0.36 mg/ml) was similar though averaged 39.3±8.9% less than V_us induced by Ca²⁺ (1.6x10^–6M) in the control fibers. Addition of Ca²⁺ (1.6x10^–6M) to a contraction induced by MLCK-resulted in small increases in both F_o and V_us. Shortening under a constant load was similar for both types of contractions. The contraction induced by MLCK-was accompanied by an increased rate of ATP hydrolysis. The MLCK-induced contraction is thus kinetically similar though not identical to a contraction induced by Ca²⁺. We conclude that with respect to actin-myosin interaction, MLCK- and Ca²⁺-induced contractions are similar.     

Velocity and myosin phosphorylation transients in arterial smooth muscle: effects of agonist diffusion

Summary Transients in myoplasmic [Ca²⁺] and in phosphorylation of the 20,000 dalton light chain of myosin have been reported following stimulation of vascular smooth muscle by various agonists. Since these transients are rapid compared with the time required to attain a steady-state stress, agonist diffusion rates may be a significant limitation in activation. The purpose of this study was to estimate the effect of agonist diffusion rates on the time course of activation as assessed by mechanical measurements of stress development and isotonic shortening velocities and by determinations of the time course of myosin phosphorylation. The approach was to measure these parameters in K⁺-stimulated preparations of the swine carotid media of varying thicknesses and to estimate the theoretical contributions imposed by diffusion rates and the presence of a diffusion boundary layer surrounding the tissue. The results show that the time course of parameters which are tissue averages such as stiffness, active stress, and myosin phosphorylation is dominated by agonist diffusion rates. The sequence of events involved in excitation-contraction coupling including agonist actions on the cell membrane, Ca²⁺ release, activation of myosin light chain kinase, and cross-bridge phosphorylation appear to be very rapid events compared with stress development. Estimates of unloaded or lightly loaded shortening velocities which are not simple tissue averages appear to provide an imporoved estimate of activation rates.Supported by a grant from the National Institutes of Health 5-PO1-HL19242. K. E. Kamm was supported by a National Heart, Lung, and Blood Institute Research Service Award HL-05957.     

扬子鳄肌肉组织成份测试和营养评价

古医籍早有记载，鳄肉可食。根据江苏省理化测试中心和南京大学现代化分析中心的测定，本文在国内首次发表了鳄肉中所含脂肪、蛋白质、氨基酸、维生素、宏量及微量元素的全部资料，说明鳄肉营养丰富，胜过猪、牛、羊、鸡、鸭肉，并具有海洋生物特有的ＤＨＡ（脑黄金）。对进一步研究怀开发我省特产扬子鳄有重要意义。     

1,6-二磷酸果糖对缺氧缺血性心、脑损害的保护作用(综述)

1，6-二磷酸果糖(FDP)是存在于一切活细胞内的糖代谢中间产物。细胞缺氧时，外源性FDP可透过细胞膜进入到细胞内直接供能，并可阻止Ca^2 内流，减少氧自由基的产生、稳定细胞膜，及减少细胞凋亡。多数研究认为FDP对缺氧缺血引起的心、脑损伤具有保护作用，但也有不同的观点。因此有必要进一步临床验证，为FDP在这方面的应用提供有价值的理论依据。