Stimulation-induced setting of postural muscle tone in the decerebrate rat

These studies demonstrate the presence of pontomedullary areas in the rat brainstem which, when stimulated electrically, serve to set postural muscle tone in the hindlimbs. Low amplitude stimulation of the dorsal tegmental field (DTF) was found to inhibit postural muscle tone and, in some rats, was found to decrease mean arterial pressure. Low amplitude stimulation of the ventral tegmental field (VTF) was found to increase postural muscle tone and, in all cases tested, was found to increase mean arterial pressure.     

颞区眼轮匝肌皮瓣修复眼睑皮肤软组织缺损

目的：探讨修复眼睑皮肤缺损的方法．方法：应用颞部眼轮匝肌皮瓣修复同侧眼睑皮肤软组织缺损１０例．其中男 ７例，女３例．缺损原因：疤痕切除后创面 ７例，色素痣切除后创面１例，化学烧伤 ２例．均为下睑皮肤软组织缺损．结果：所有病例皮瓣成活良好，外形效果满意．结论：颞部眼轮匝肌皮瓣血供可靠，转移方便，皮肤质地、厚度与眼睑皮肤相近，是一个修复眼睑皮肤缺损的理想的皮瓣．     

美维松对膈肌功能的影响

目的：研究不同剂量美维松对膈肌和拇收肌的抑制时程与恢复过程。方法：３０例ＡＳＡⅠ级的成年手术患者，按美维松用量分成两组，Ⅰ组：０．１６ｍｇ／ｋｇ，Ⅱ组：０．２０ｍｇ／ｋｇ，每组１５例。同步测定跨膈肌压（Ｐｄｉ）和拇收肌对连续四次刺激（ＴＯＦ）反应的Ｔ１（ＡＰＴ１）及ＴＯＦｒ值。结果：显示两组ＡＰＴ１最大抑制相近，是Ｐｄｉ的１．７倍。Ｐｄｉ达到最大抑制及恢复到７５％的时间比ＡＰＴ１快得多。结论：提示美维松对膈肌收缩功能的抑制比拇收肌差，但恢复迅速。     

Infantile myofibromatosis

 Infantile myofibromatosis is a mesenchymal tumor most commonly seen in infancy. The tumors have a variable appearance on CT/MR and often simulate a more aggressive neoplasm. This report describes CT/MR findings in cases of infantile myofibromatosis with pathologic correlation. Discussion into the success of imaging in suggesting the correct diagnosis is also addressed. Infantile myofibromatosis is a mesenchymal disorder of infancy characterized by the presence of tumorous nodules in the skin, subcutaneous tissue, muscle, viscera, and bone. Cases of solitary and multiple lesions have been described. We present the clinical, histologic, and radiographic findings of one case of the solitary form of infantile myofibromatosis that was recently diagnosed at our hospital.     

Leakage of carbonic anhydrase III from normal and denervated rat skeletal muscle following contractile activity.

Skeletal muscle extracellular carbonic anhydrase III was investigated in anesthetized rats by a microdialysis technique. A small dialysis probe was inserted into the tibialis anterior (TA) muscle and perfused continuously. Perfusates were collected before and during muscle contraction, induced by electrical stimulation of the muscle or of the sciatic nerve. In the perfusate of resting normal and denervated muscle, the concentration of CA III was 10 to 12 ng/mL, as measured by a radioimmunosorbent technique. During contractile activity, the concentrations of CA III increased markedly in the normal and denervated muscle. A TA muscle suspended in physiological saline behaved similarly, even though the leakage before and during contraction was higher than in vivo. The results show that skeletal muscle leaks CA III both in vivo and in vitro, a leakage which was markedly increased by contractile activity. The microdialysis technique should also be useful in humans to study the efflux of various proteins from different kinds of diseased or fatigued muscles.     

Persistence of Mammary Artery Branches and Blood Supply to the Left Anterior Descending Artery

Background. Partial harvesting of the left internal mammary artery (LIMA) is a widespread technique used during minimally invasive coronary operations performed through a left anterior small thoracotomy. The influence of persisting LIMA branches was investigated to evaluate their effect on the blood flow of the left anterior descending artery.

Methods. Thirty patients, 15 with totally (group A) and 15 with partially (group B) harvested LIMAs, were evaluated. All the patients underwent postoperative angiography, during which a flow map of the LIMA was performed. The average peak velocity and the diastolic-to-systolic peak velocity ratio were recorded. The LIMA graft flow pattern was recorded in the proximal and distal thirds of the artery. Intramammary adenosine (12 to 14 μg) was injected and the average peak velocities before and after injection were calculated.

Results. The average peak velocity was similar in both groups in the proximal and distal thirds of the LIMA (25 ± 7 and 26 ± 5 cm/sec, respectively, in group A versus 27 ± 5 and 25 ± 5 cm/sec, respectively in group B; p = NS). The diastolic-to-systolic peak velocity ratio was similar proximally (0.78 ± 0.3 in group A versus 0.69 ± 0.3 cm/s in group B; p = NS), but not distally (1.72 ± 0.1 in group A versus 0.97 ± 0.3 in group B; p < 0.0005). The LIMA graft flow reserve was similar both proximally and distally (2.6 ± 0.6 and 2.5 ± 0.3 cm/s, respectively, in group A versus 2.6 ± 0.5 and 2.6 ± 0.3 cm/s, respectively, in group B; p = NS).

Conclusions. The persistence of LIMA branches does not influence the blood flow of the left anterior descending artery after acute adenosine-induced myocardial hyperemia. If a left anterior small thoracotomy is used in left anterior descending artery direct revascularization, complete LIMA harvesting is not mandatory and depends on the personal preference of the surgeon.     

Hyperglycaemia compensates for the defects in insulin-mediated glucose metabolism and in the activation of glycogen synthase in the skeletal muscle of patients with Type 2 (non-insulin-dependent) diabetes mellitus

Summary Insulin resistance and a defective insulin activation of the enzyme glycogen synthase in skeletal muscle during euglycaemia may have important pathophysiological implications in Type 2 (non-insulin-dependent) diabetes mellitus. Hyperglycaemia may serve to compensate for these defects in Type 2 diabetes by increasing glucose disposal through a mass action effect. In the present study, rates of whole-body glucose oxidation and glucose storage were measured during fasting hyperglycaemia and isoglycaemic insulin infusion (40 mU·m^–2min^–1, 3 h) in 12 patients with Type 2 diabetes. Eleven control subjects were studied during euglycaemia. Biopsies were taken from the vastus lateralis muscle. Fasting and insulin-stimulated glucose oxidation, glucose storage and muscle glycogen synthase activation were all fully compensated (normalized) during hyperglycaemia in the diabetic patients. The insulin-stimulated increase in muscle glycogen content was the same in the diabetic patients and in the control subjects. Besides hyperglycaemia, the diabetic patients had elevated muscle free glucose and glucose 6-phosphate concentrations. A positive correlation was demonstrated between intracellular free glucose concentration and muscle glycogen synthase fractional velocity insulin activation (0.1 mmol/l glucose 6-phosphate: r=0.65, p<0.02 and 0.0 mmol/l glucose 6-phosphate: r= 0.91, p<0.0001). In conclusion, this study indicates an important role for hyperglycaemia and elevated muscle free glucose and glucose 6-phosphate concentrations in compensating (normalizing) intracellular glucose metabolism and skeletal muscle glycogen synthase activation in Type 2 diabetes.     

不同浓度的金属硫蛋白对离体豚鼠乳头肌缺氧、复氧电生理特性的影响

为探讨金属硫蛋白（MT）对豚鼠乳头肌缺血再灌注损伤所致心律失常的影响，利用标准玻璃微电极技术，采用缺氧及复氧豚鼠乳头肌模型，模拟体内缺血再灌注损伤，观察不同浓度MT对豚鼠乳头肌电生理特性的影响。结果显示低浓度的MT（0．002mmol／L）对正常及缺氧和复氧豚鼠乳头肌的动作电位（AP）有关参数及自律性均无影响；中等浓度的MT（0．02mmol／L）仅使正常乳头肌的AP复极达50％时程（APD50）缩短24％（P＜0．05），但使缺氧乳头肌的AP复极达20％时程（APD20）、APD50和AP复极达90％时程（APD90）分别缩短68％、56％和43％（P均＜0．01），并使静息电位（RP）、AP幅值（APA）和0相最大上升速率（Vmax）分别增加30％、30％和45％（P均＜0．01）；高浓度的MT（0．1mmol／L）使正常豚鼠乳头肌的APD20、APD50和APD90分别缩短57％、54％和50％（P均＜0．01），并且RP、APA及Vmax分别下降22％（P＜0．05）、28％（P＜0．01）和29％（P＜0．05），而使缺氧豚鼠乳头肌的APD20、APD50和APD90分别延长92％、78％和50％（P均＜0．01），对RP、APA及Vmax无明显影响。在复氧期间，0．02mmol／L的MT可使自律性的发生率从77．8％降至55．6％（P＜0．05）；而0．1mmol／L的MT则使自律性的发生率从77.8％降至22．2％（P     

Differential effect of oestrogen on post‐exercise cardiac muscle myeloperoxidase and calpain activities in female rats

The effects of oestrogen administration on 1 h post‐exercise cardiac muscle myeloperoxidase (MPO) and calpain activities were determined in female rats. Rats were ovariectomized and implanted for 2 weeks with either oestrogen (25 mg 17‐oestradiol) or placebo pellets or left with ovaries intact. Rats were then run for 1 h at 21 m min^–1, 12% grade, killed 1 h post‐exercise and cardiac muscle and blood samples were removed. Control animals from each group were killed without prior exercise. Serum oestrogen levels in the order of the highest to lowest were; ovariectomized oestrogen replaced rats > intact ovaries rats > ovariectomized placebo rats. Oestrogen induced significant (P < 0.05) elevations in cardiac MPO activity at rest and at 1 h post‐exercise in ovariectomized rats. No significant elevations in cardiac MPO activity were evident in placebo ovariectomized or normal ovary rats at rest or post‐exercise. Cardiac calpain activities were similar in all unexercised groups. Ovariectomized placebo and intact ovary rats had significantly (P < 0.05) elevated cardiac calpain activities 1 h post‐exercise while calpain activity was not significantly elevated in hearts from ovariectomized oestrogen rats. These results demonstrate that oestrogen supplementation in ovariectomized rats induces elevations in cardiac muscle MPO activities at rest and at 1 h post‐exercise. This is opposite to the effect of oestrogen in post‐exercise skeletal muscle and implies a greater neutrophil infiltration into cardiac muscle caused by oestrogen. This effect cannot be explained by changes in 1 h post‐exercise cardiac muscle calpain activity, the elevation of which was suppressed by oestrogen administration. Oestrogen influences cardiac calpain activity similarly to its effect in skeletal muscle. Thus, oestrogen administration to ovariectomized rats induces elevations in cardiac MPO activity while suppressing cardiac calpain activity.     

Canine Latissimus Dorsi Muscle: An Apparatus for Isometric Force Measurements

Abstract: This paper describes a device used to measure the isometric forces generated during electrical stimulation of the canine latissimus dorsi muscle in vivo with a preserved neurovascular supply. This device uses 2 strain gauge force sensors linked to a movable alignment frame to which the muscle is attached. The muscle length is controlled by the application of known weights to the system. The device has a frequency of response of 17.5 Hz and compliance of -0.1 mm N^-1, and its experimental performance was tested in the anesthetized mongrel dog.