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.     

二硫化碳对大鼠胚胎发育及血清锌和铜含量影响的研究

本文观察了CS_2对大鼠胚胎发育及血清锌、铜含量的影响。发现胚胎着床前死亡率升高,胎鼠皮下出血、心包淤血及骨骼骨化不金的发生率增高。但无明显的致畸效应。14.1及103.9ng/m~3的CS_2对妊娠大鼠的血清锌、铜含量无明显影响。说明CS_2对大鼠的胚胎毒性与其对妊娠大鼠血清锌、铜含量的影响之间没有关联。     

穹隆-海马伞切断对大鼠脑内TrkA表达的影响

①目的　探讨穹隆 海马伞切断对大鼠脑内不同部位神经生长因子受体TrkA表达的影响及临床意义。②方法　成年健康雌性Wistar大鼠 10只 ,随机分为穹隆 海马伞切断模型组和假手术组。两组大鼠均常规取海马CA1区、皮质区、杏仁复合体区、基底前脑Meynert核等部位脑组织与假手术组比较TrkA阳性细胞表达情况。③结果　假手术组大脑各观察区有基础水平的TrkA表达。模型组大脑海马CA1区、大脑皮质区、杏仁复合体区以及Meynert核区TrkA阳性细胞数明显减少 (t=3.94 4～ 8.4 4 2 ,P <0 .0 5 )。 ④结论　穹隆 海马伞切断可致大鼠脑内多部位TrkA表达减少 ,其可能是导致认知和情绪损伤的原因之一。     

The effect of the fiber components cellulose and lignin on experimental colon neoplasia

Sixty Sprague-Dawley rats were pair-fed one of three nutritionally identical diets. One diet contained “low-fiber” (3.8% crude fiber); the others contained “high fiber” (28.7% crude fiber) composed of either cellulose or lignin. Although both “high fiber” diets had similar stool bulking effects, only the cellulose diet was associated with a reduction in 1,2-dimethylhydrazine (DMH)-induced colon neoplasms. The cellulose diet was also associated with distinct changes in the gut bacterial profile and with a lowered serum cholesterol. © 1993 Wiley-Liss, Inc.     

脉冲Nd：YAG激光照射对大鼠炎症牙龈组织的作用

患实验性牙龈炎的大鼠牙龈（６例）经脉冲掺钕钇铝柘榴石激光（Ｎｄ：ＹＡＧ激光）照射后进行光镜及超微结构观察。目的在于了解低能量Ｎｄ：ＹＡＧ激光照射对牙龈炎症的治疗作用。炎症牙龈经输出能量为１．５Ｗ，脉冲数为２０ＰＰＳ的激光照射后与对照组相比较，形态学上有如下变化：上皮细胞无变性；牙龈上皮层数较炎症时减少；上皮下炎细胞浸润明显减少；上皮细胞间隙变小；上皮下结缔组织内产生大量的排列致密的胶原纤维。结果提     

Ketanserin降低清醒自发性高血压大鼠血压波动性的机理初探

应用计算机化清醒大鼠血流动力学测定技术，观察５－ＨＴ２受体阻滞剂Ｒｉｔａｎｓｅｒｉｎ（Ｒｉｔ）和α１受体阻滞剂哌唑嗪对清醒自发性高血压大鼠（ＳＨＲ）的血压、血压波动性（ＢＰＶ）和动脉压力感受性反射血压控制部分（ＡＢＲ－ＢＰ）的效应，旨在初步探讨兼具５－ＨＴ２受体和α１受体阻滞作用地新型抗高血压药Ｋｅｔａｎｓｅｒｉｎ降低ＢＰＶ的机制。结果表明：Ｒｉｔ对ＳＨＲ无降压作用，但侧脑室给药明显提高ＡＢＲ－Ｂ     

Spinal cord restitution following compression injuries in rats

Spinal cord compression injuries were produced in rats by applying weights to a plate 2.2 x 50 mm in size, placed on the exposed midthoracic dura covering the spinal cord. The influence of force and duration of compression was studied by using 3 different weights, 20, 35 and 50 g, applied for 1, 5 and 10 min. Postoperative neurological function was tested by the inclined plane method and the rats were observed for 3 weeks. Neurological impairment increased with force and duration of compression. It is therefore reasonable to conclude that patients suffering from spinal cord injury should be investigated immediately for signs of persistent cord compression. If this is present, early decompression might be of value, although nothing is known in man concerning the limits of force and duration of compression permitting postoperative neurological recovery.     

交链孢酚单甲醚在大鼠小鼠体内的分布

对食管癌高发区粮食中分离的互隔交链孢霉的毒素交链孢酚单甲醚(AME)在大鼠、小鼠体内的分布进行研究。给动物腹腔内注射氚标记的交链孢酚单甲醚(~3H-AME),然后在不同时间测各脏器的放射性。结果表明:在所测9个脏器中,2h肝脏含量最高,食管下段在大小鼠分别居第四和第三。但大小鼠分别在72、24h则以食管下段最高,说明AME及其代谢物在此清除较慢,即对其有较高的亲和力。     

大鼠肺微血管和肺泡铸型的扫描电镜观察

用扫描电镜观察以甲基丙烯酸甲酯灌注鼠的肺微血管和肺泡。胸膜下毛细血管较稀疏,网孔粗大。毛细血管部分成锐角折返,亦可见毛细血管盲端。肺泡隔毛细血管均成扁平状膨大,且相互吻合成单层密集网。肺泡铸型为大小不等、不规则的多面体,表面可见肺泡Ⅱ型细胞核之压迹。两肺泡之间可见呈桥式连接的肺泡孔,亦可见部分呈三通管样相连。