牛磺酸对小鼠脾细胞DNA损伤的影响

目的探讨牛磺酸对紫外线所致小鼠脾细胞ＤＮＡ损伤的影响。②方法小鼠饲料中分别添加牛磺酸、维生素Ｃ（ＶｉｔＣ）和维生素Ｅ（ＶｉｔＥ）喂养１１２ｄ后,荧光法（ＦＡＤＵ法）检测小鼠脾细胞ＤＮＡ链的断裂程度,并与对照组比较。③结果紫外线照射前,小鼠脾细胞ＤＮＡ链断裂程度各组间差异无显著性（Ｆ＝０．８７５６,Ｐ＞０．０５）;紫外线照射后,牛磺酸、ＶｉｔＣ,ＶｉｔＥ各组脾细胞ＤＮＡ双链剩余率高于对照组,差异均有显著性（Ｆ＝２０．４５,ｑ＝３．０１～４．０８,Ｐ均＜０．０５）。④结论牛磺酸可减轻紫外线对小鼠脾细胞ＤＮＡ分子的损伤。     

二硫化碳作业女工早期胚胎损伤的剂量反应关系

目的 探讨女工二硫化碳（ＣＳ２）接触水平与胚胎早期发育障碍之间的剂量－反应关系。方法 前瞻观察生育女工妊娠所需的月 经周期数;收集每个月经周期胚胎植入期尿样,检测绒毛膜促性腺激素含量;监测女工作业地点ＣＳ２浓度。结果 ２５７名接触组经临床确诊妊娠的女工,各月经周期妊娠机率低于３６６名对照组女工,时间妊娠率随女工ＣＳ２接触水平（ＣＳ２接触浓度以ＣＳ２接触工龄）升高而降低：妊娠率＝０．７０３３－０．０     

新生儿缺氧缺血性脑损伤亚低温干预大鼠模型的建立

为探讨不同疗程亚低温对新生儿脑损伤的保护作用,建立新生儿缺血缺氧性脑损伤亚 温干预大鼠模型,先在７日龄清洁级ＳＤ大鼠上以右颈总动脉结扎术和吸入低氧浓度气体法制备缺血缺氧性脑损伤（ＨＩＢＤ）模型,再将其随机分为室温恢复组（ＲｏＴ组,ｎ＝４４）和３种疗程（２４ｈ,４８ｈ,７２ｈ）的亚低温干预组（Ｈｙ２４组,ｎ＝２６,Ｈｙ４８组,ｎ＝１４,Ｈｙ７２组,ｎ＝２０）。亚低温干预期间采用配方奶喂养,并监测脑温     

丹参对耳蜗辐射防护作用的实验研究

为探讨内耳辐射损伤的防治,采用丹参作为保护药物,用相同剂量的６０Ｃｏ γ射线照射丹参防护组和单纯放射组豚鼠耳颞部,２ 周后作形态与机能检查。结果发现：丹参防护组耳蜗机能与结构损害较轻,而单纯放射组耳蜗机能明显受损,血管纹和柯替氏器病变严重;复合动作电位（ＣＡＰ） 反应阈和毛细胞损伤率两组比较差异有显著性（ Ｐ ＜ ０ ．０１） 。表明丹参对内耳辐射损伤有保护作用。     

Bioprosthetic heart valves--replacing order with chaos: electron microscopic study

Rheumatic heart disease is a significant clinical entity in young children, especially in the developing world. One of the major long-term effects of ill managed rheumatic fever is irreversible damage to the cardiac valve leaflets, primarily on the left side. With the limited success of currently available mechanical and bioprosthetic valves, there is an urgent need for new directions in bioprosthetic valves, both in material, including source, degree of fixation, surface, bulk modifications, etc., and design. In the present paper, new proposals in the material selection and fabrication of bioprosthetic valves are proposed based on electron microscopic studies of natural valve leaflets and the pericardial surface. Current approaches for bioprosthetic valve fabrications include the wide use of the pericardium as a leaflet material. The present study indicates a need for nondestructive surface examination of pericardial sheets for the elimination of areas of surface voids resulting from gross fiber disorientation. Also, there seems to be a need for incorporation of an in situ fiber renewal mechanism in bioprosthetic leaflets to emulate the natural valve more closely. Apparently natural leaflets have built-in fiber renewal mechanism(s).     

一氧化氮等自由基对矽肺患者损伤效应的研究

检测７３例矽肺患者和６０例健康对照者血浆一氧化氮（Ｐ－ＮＯ）、维生素Ｃ（Ｐ－ＶＣ）、维生素Ｅ（Ｐ－ＶＥ）、β－胡萝卜素（Ｐ－β－ＣＡＲ）、过氧化脂质（Ｐ－ＬＰＯ）及红细胞超氧化物歧化酶（Ｅ－ＳＯＤ）、过氧化氢酶（Ｅ－ＣＡＴ）、谷胱甘肽过氧化物酶（Ｅ－ＧＳＨ－ＰＸ）和过氧化脂质（Ｅ－ＬＰＯ）值的结果表明,与对照组比较,患者组Ｐ－ＶＣ、Ｐ－ＶＥ、Ｐ－β－ＣＡＲ、Ｅ－ＳＯＤ、Ｅ－ＣＡＴ、Ｅ－ＧＳＨ－ＰＸ平均值均显著降低（Ｐ＜０．００１）,Ｐ－ＮＯ、Ｐ－ＬＰＯ、Ｅ－ＬＰＯ平均值均显著升高（Ｐ＜０．００１）;上述检测值与患者病程、病情、肺功能状态均有相关;逐步回归表明,患者病程与Ｐ－ＮＯ、Ｐ－ＶＥ、Ｅ－ＳＯＤ、Ｅ－ＬＰＯ值相关最为密切;提示矽肺患者体内一氧化氮和氧自由基反应病理性加剧,氧化抗氧化平衡严重失调     

Modification of low density lipoprotein potentiates its inhibitory effect on catecholamine secretion in cultured bovine adrenal medullary cells

Low density lipoprotein (LDL) and lipoprotein(a) suppress catecholamine secretion in cultured adrenal medullary cells. Modification of LDL by oxidation or acetylation potentiates various atherogenic actions of LDL. In the present study, we investigated whether the modification of LDL influences catecholamine secretion in cultured bovine adrenal medullary cells. The exposure of LDL to CuSO₄ caused a time-dependent oxidation of LDL. Maximal oxidation of LDL was observed after exposure to CuSO₄ for 24 h. Native LDL inhibited catecholamine secretion induced by carbachol to 68.5% of control. Oxidized LDL caused further inhibition of carbachol-evoked secretion to 37.6% of control. Acetylated LDL inhibited it to 41.0% of control. There was a good correlation between the extent of LDL oxidation and the inhibition of catecholamine secretion. These results suggest that oxidation or acetylation of LDL augments its inhibitory effect on the secretion of catecholamines. Since catecholamines are a risk factor of atherosclerosis, the inhibitory effect by such modified LDL may be a mechanism inhibiting atherosclerotic progression. Received: 29 January 1999 / Accepted: 19 April 1999 / Published online: 22 June 1999     

Synthesis and analgesic and anti-inflammatory activities of 1,2-benzothiazine derivatives

Three 1,2-benzothiazine derivatives were synthesized, and their analgesic/anti-inflammatory efficacy and their effects on gastric irritation were evaluated. Among the three compounds, 39 exhibited the most potent analgesic action, but the effect was weaker than that of piroxicam. Nonetheless, the compound showed 4 times more potent analgesic action with less gastric damage than did ibuprofen. These compounds did not show anti-inflammatory effect at an oral dose of 5 mg/kg.     

Influence of environmental and genetic factors on variation in human response to DNA damaging agents

Exogenous DNA damaging agents must be considered in the context of endogenous reactive species which have the potential to damage DNA. Although a no-effect level for a DNA-damaging compound may not exist, it may be feasible to define a level where reducing exposure to the compound is no longer the most effective way of reducing human risk. Modifying environmental factors which affect human response to damage may be the better strategy. Although a number of rare human syndromes are associated with a reduced ability to repair DNA damage, it is not clear how wide is the range of genetic variation in repair capacity among normal individuals. Studies with DNA repair-deficient human syndromes indicate that processes other than mutation and DNA repair must be involved in the development of cancer, and these processes may represent new sources of variation in human response to genotoxic agents.     

Visual performance in the rhesus monkey after exposure to blue light.

Rhesus monkeys trained to perform a visual task (Landolt ring discrimination) were exposed for 1000 sec to known amounts of 441 nm light by means of a 2500 W xenon lamp with narrow bandpass filter. Radiant exposures to the macula of 30 J/cm² did not impair vision, but 60 J/cm² produced a transient loss of 20/20 vision which lasted from 20 to 30 days. A radiant exposure of 90 J/cm² produced a permanent loss of 20/20 vision. These results, in addition to explaining solar retinitis and eclipse blindness, correlate well with the retinal photopathology of the short wavelength photochemical lesion.