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).     

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.     

Dose-incidence curves for tumour control and normal tissue injury, in relation to the response of clonogenic cells

A probit analysis has been made of data from the literature on local control of tumours and injury to normal tissue as a function of dose of radiation. Fifteen series were analysed for local tumour control in man and ten series for complications. The analysis yielded values for the D50 dose (50% incidence of effect) and the probit width (K), a measure of the steepness of the dose-incidence curve. The same analyses were made of data for rodents. Broadly, K was proportional to D50 in the ratio 1:7, with no major differences between tumours and reported complications. D50 was plotted as a function of dose per fraction for four normal tissues and two tumours in rodents. D50 decreased more rapidly with increasing dose per fraction for the normal tissues than for tumours. The probit width, K, varied inversely with increasing dose per fraction for normal tissues and this contrasted with the tumour response. Thus with increasing dose per fraction, the threshold for effect decreased and the steepness of the ensuing dose-incidence curve increased, relatively more rapidly for normal tissue than for tumour. These curves of gross response have been analysed also by the double negative log method of Gilbert [23], in an attempt to estimate the number and survival characteristics of "tissue-rescuing cells". These were calculated to be less than 1 in 10(4) of the numbers of clonogenic cells measured by excision assays. The D0 values of the derived survival curves for these tissue-rescuing cells were higher than those measured by excision assays.     

An acute fatal occupational cadmium poisoning by inhalation

Summary A 43-year-old male smelter was admitted to a hospital on account of severe dyspnea about 2 days after exposure to brownish-yellow smoke produced by melting of copper scrap. On admission pronounced hypoxemia was revealed, and an oxygen-enriched gas was administered after intubation. Although inspired oxygen concentration was gradually increased, hypoxemia progressed and he died on day 11 in hospital.The principal autopsy finding was chiefly confined to the lungs. Both lungs were heavy (the left weighing 1,470 g; the right 1,710 g) and firm to the touch. Histologically, no normal alveoli were found throughout the entire lung. Some alveolar spaces were occupied by pneumocytes, others by organized exudate with fibrosis. Interstitial fibrosis was present. Patchy areas of inflammatory cell infiltrations as well as intra-alveolar hemorrhages were observed. On the basis of the above findings a diagnosis of diffuse alveolar damage was made.Based on the available evidence (presence of cadmium in the copper scrap, feature of the smoke, clinical signs with latent time, and high cadmium concentration of the lung), the diffuse alveolar damage was considered to have been caused by inhaled cadmium. The pulmonary change of the present case was more advanced in pathologic stage in comparison with those reported in the literature.