小鼠系统性白色念珠菌感染的免疫研究

[目的]探讨白色念珠菌免疫小鼠的T细胞、腹腔巨噬细胞和免疫血清,在抗小鼠全身性白色念珠菌感染申各自所起的作用.[方法]将60只健康昆明种小鼠随机分组,分别进行下述试验. (1)体内试验:将致敏T细胞、腹腔巨噬细胞、免疫血清分别过继给同品系小鼠后,尾静脉注射0.2 ml白色念珠菌液(2×107 CFU/ml),观察小鼠存活情况; (2)体外试验:将上述细胞、免疫血清分别与0.1 ml白色念珠菌液(1×105 CFU/ml)共同培养,计数菌落形成单位(CFU),判定细胞和免疫血清对白色念珠菌的作用效应.[结果](1)感染后第4周,过继腹腔巨噬细胞和致敏T细胞组小鼠存活率分别为50%和60%;过继免疫血清和生理盐水组小鼠全部死亡; (2)体外实验发现腹腔巨噬细胞对白色念珠菌具有明显抑杀作用,菌落数(2.33±0.58×104 CFU/ml)显著低于对照组(9.33±2.51×104 CFU/ml),而免疫血清组菌落数(76.00±3.60×104 CFU/ml)显著高于对照组.[结论]小鼠巨噬细胞在抗白色念珠菌感染中发挥重要作用,免疫血清没有保护作用.     

除草剂西玛津对小鼠的免疫毒性作用

目的 探讨均三氮苯类除草剂西玛津对小鼠的免疫毒性.方法 BALB/c小鼠30只,按体重随机分为5组,每组6只,分别为西玛津90、200、400 mg/k(g染毒剂量组(每日1次,连续21 d灌胃染毒),阴性对照组(予蒸馏水)和阳性对照组(腹腔注射20 mg/kg环磷酰胺).观察小鼠体重变化、脾脏和胸腺的脏器系数、脾脏T细胞转化增殖能力以及血清中白细胞介素(IL)-2、IL-4、IgG和IgM含量.结果 200与400 mg/kg染毒组小鼠体重、脾脏和胸腺脏器系数以及T细胞转化增殖能力均明显低于阴性对照组,差异均有统计学意义(P＜0.05或P＜0.01);200mg/kg染毒组小鼠血清中IL-2、IL-4、IgG和IgM含量分别为(108.50±3.20)pg/ml、(36.54±3.36)pg/ml、(46.25±7.41)μmg/ml、(17.58±2.23)μg/ml;400 mg/kg染毒组小鼠血清中IL-2、IL-4、IgG和IgM含量分别为(85.70±4.00)pg/ml、(35.92±2.29)pg/ml、(40.08±6.80)μg/ml、(11.92±3.23)μg/ml,均明显低于阴性对照组,差异均有统计学意义(P＜0.05或P＜0.01).结论 西玛津对小鼠细胞免疫和体液免疫功能均有抑制作用.     

经氯化处理的生活污水的有机提取物对DNA的损伤

目的 了解氯化后生活污水中有机提取物对DNA的损伤作用,为今后防治其危害提供科学依据.方法 于2006年3月,采集甲大学、某饭店、乙大学的生活污水氯化前、后水样,采用其有机提取物对BALB/C小鼠分别进行彗星试验(0.04、0.2、1.0、5.0 mg/ml)、微核试验(高、中、低剂量组分别相当于提取物原液、20%原液、5%原液)和Ames试验(0.01、0.1、1.0、10、100μl/皿),检测水样有机提取物对DNA的损伤作用.结果 彗星试验显示,氯化前甲大学、某饭店、乙大学1.0、5.0 mg/ml组和氯化后甲大学0.04～5.0 mg/ml 组、某饭店0.2～5.0 mg/ml组、乙大学1.0、5.0 mg/ml组小鼠脾脏细胞头部染色体DNA含量百分比低于溶剂对照组,差异均有统计学意义(P＜0.05).氯化后各染毒组小鼠脾脏细胞头部染色体DNA含量百分比低于氯化前.微核试验显示,氯化前甲大学、某饭店高剂量组雌性小鼠和甲大学、某饭店高、中剂量组雄性小鼠以及氯化后甲大学高、中剂量组、某饭店高、中、低剂量组雌、雄性小鼠骨髓细胞微核率高于溶剂对照组,差异均有统计学意义(P＜0.05).Ames试验显示,氯化前某饭店100μl/皿组TA98-S9和甲大学、某饭店10、100μl/皿组TA98 S9以及氯化后某饭店10、100μl/皿组TA98-S9和甲大学、某饭店1.0～100μl/皿组TA98 S9的回变菌落数是空白对照组的2倍以上,且均呈一定的剂量-反应关系;而甲大学、某饭店、乙大学有机提取物对TA97、TA100、TA102均未引起阳性反应.结论 氯化后生活污水的有机提取物对DNA有损伤作用,且强于氯化前.     

消炎痛、Hp联合复制小鼠胃炎模型的实验研究

目的 探讨以消炎痛、幽门螺杆菌(Hp)联合应用的方法建立小鼠胃炎动物模型.方法 BALB/c小鼠,小鼠断食断水12h后给予模型组小鼠皮下注射5mg/ml消炎痛NaHCO3溶液0.3mg/10g,12h后再给予HP新鲜混悬菌液(109CFU/ml)0.4ml灌胃,1h后恢复正常饮食.每2天重复1次,连续6次.结果 与对照组相比,胃炎模型组小鼠胃粘膜损伤严重,有炎症细胞浸润及Hp定植.结论 采用消炎痛、幽门螺杆菌(Hp)联合应用的方法建立的胃炎小鼠模型,其病理变化持续、稳定,方法简单易行,发生率高,适合于实验细菌学研究.     

IL-12单克隆抗体对克罗恩病模型小鼠Th1/Th2免疫平衡的调节作用

目的研究白细胞介素-12(IL-12)单克隆抗体对克罗恩病模型小鼠辅助性T细胞1/辅助性T细胞2(Th1/Th2)免疫平衡的调节作用。方法选择BALB/c健康小鼠30只,将30只小鼠分为正常对照组(10只)和实验小鼠(20只),实验组小鼠做克罗恩病模型,建模成功后将实验组小鼠分为克罗恩病组和IL-12单克隆抗体组各10只,IL-12单抗组小鼠腹腔注射IL-12单抗(25 mg/kg),正常对照组和克罗恩病组小鼠腹腔注射0.2 ml的生理盐水。处理4周后,对三组小鼠疾病活动程度、结肠重量、结肠长度进行评价,使用酶联免疫吸附试验法检测三组小鼠结肠组织中Th1型细胞因子干扰素-γ(IFN-γ)、肿瘤坏死因子-α(TNF-α)、IL-1β、IL-8和Th2型细胞因子IL-4、IL-10及IL-12、IL-23表达水平。结果克罗恩病组小鼠疾病活动程度评分、结肠组织中Th1型细胞因子IFN-γ、TNF-α、IL-1β、IL-8、IL-12、IL-23分别为(4.12±0.23)分、(563.49±21.36)ng/ml、(120.69±6.69)ng/L、(43.73±3.58)ng/ml、(179.68±4.26)ng/ml、(148.69±6.58)ng/L、(762.58±26.58)pg/ml高于IL-12单克隆抗体组(1.62±0.17)分、(472.59±15.64)ng/ml、(106.25±3.27)ng/L、(37.62±2.16)ng/ml、(163.57±3.12)ng/ml、(98.67±5.12)ng/L、(412.68±16.98)pg/ml)和对照组,而结肠重量/长度为(42.36±3.16)mg/cm大于IL-12单克隆抗体组(33.59±2.07)mg/cm)和对照组小鼠;结肠组织中Th2型细胞因子IL-4、IL-10为(55.27±1.62)pg/ml、(90.27±3.68)pg/ml低于IL-12单克隆抗体组(61.27±2.21)pg/ml、(98.67±1.68)pg/ml)和对照组(P<0.05)。结论IL-12单克隆抗体通过改善Th1型细胞因子、Th2型细胞因子的异常表达,对Th1/Th2免疫平衡进行调节,进而抑制克罗恩病的炎症反应,起到治疗的效果。     

T-2毒素对原代培养的小鼠睾丸间质细胞睾酮合成的影响

目的 探讨T-2毒素对原代培养的小鼠睾丸间质细胞(Leydig cells)睾酮合成的影响.方法 建立健康清洁级成年雄性昆明小鼠睾丸间质细胞原代培养模型,使细胞悬液密度为5×10~3个/ml,采用改进3β-羟基类固醇脱氢酶(HSD)染色法进行纯度鉴定.将其分为空白对照[0 ng/ml人绒毛膜促性腺激素(human chorionic gonadotrophin,hCG)+0 mol/L T-2毒素]组、诱导对照(10 ng/ml hCG+0 mol/L T-2毒素)组、10 ng/ml hCG+10~(-9)mol/L T-2毒素组、10 ng/ml hCG+10~(-8)mol/T~(-2)毒素组、10 ng/ml hCG+10~(-7) mol/L T-2毒素组,培养24 h后检测睾酮含量.结果 新鲜分离的小鼠睾丸间质细胞在有血清培养液中培养24h后,细胞贴壁良好,其纯度在90%以上.在10ng/ml hCG诱导下,原代培养的小鼠睾丸Leydig细胞培养液中睾酮合成量明显增加,差异有统计学意义(P＜0.05).与诱导对照组相比,10 ng/ml hCG+10~(-7)、10~(-8)、10~(-9)mol/的T-2毒素染毒组培养液中睾酮合成量均降低,差异有统计学意义(P<0.05或P<0.01);且睾酮合成量随着T-2毒素染毒浓度的升高而降低.结论 T-2毒素可以直接降低原代培养的小鼠Leydig细胞睾酮合成功能.

Abstract：

Objective To investigate the effects of T-2 toxin on testosterone biosynthesis in primary cultured Leydig cell derived from the mouse testis.Methods Leydig cells isolated from Kunming male mice were adjusted to 5×10~5/ml and the purity was identified by the modified 3β-hydroxysteroid dehydrogenase(HSD) staining method.Blank control group(treated with 0 n/ml hCG and 0 mol/L T-2 toxin),inductive control group(treated with 10 ng/ml hCG and 0 mol/L T-2 toxin),low dose T-2 toxin exposure group(treated with 10 ng/ml hCG and 10~(-9) mol/L T-2 toxin),middle dose T-2 toxin exposure group(treated with 10 ng/ml hCG and 10~(-8) mol/L T-2 toxin) and high dose T-2 toxin exposure group(treated with 10 ng/ml hCG and 10~(-7) mol/L T-2 toxin)were designed,respectively.The testosterone level was measured after 24 h of incubation.Results After 24 hours culture in liquid medium contained serum,the fresh isolated Leydig cells grew well and the purity exceeded 90%.Through 10 ng/ml hCG induce,the testosterone level of Legdig cells increased significantly and the difference compared to blank control was of statistical sense (P<0.05).Compared to inductive control group,the testosterone level in Legdig cells decreased significantly in all T-2 toxin exposure groups with a dose dependant manner (P<0.05 or P<0.01).Conclusion T-2 toxin can directly decrease the testosterone biosynthesis of the primary Leydig cells derived from the mouse testis.     

海洋蛋白肽对小鼠免疫调节作用的实验研究

目的 探讨海洋蛋白肽(marine protein peptide,MPP)对小鼠的免疫调节作用及其可能的机制.方法 以小鼠为动物模型,观察不同剂量(0.22 g/kg、0.45 g/kg和1.35 g/kg)MPP对小鼠体重、免疫器官相对重量、细胞免疫功能、体液免疫功能、单核巨噬细胞功能、NK细胞活性、脾脏T淋巴细胞亚群以及血清中细胞因子的影响.结果 MPP 0.22 g/kg剂量组Con A诱导的小鼠淋巴细胞增殖能力(0.33±0.21)和足跖肿胀度(0.36±0.11)mm,较对照组的相应两值(0.15±0.10)和(0.21±0.10)mm均有显著提高.溶血空斑数对数转换值在MPP 0.22 g/kg组(1.64±0.06)、0.45 g/kg组(1.59±0.05)和1.35 g/kg组(1.56±0.10)中均显著高于对照组(1.38±0.10);血清半数溶血值在MPP 0.22 g/kg(141.00±23.00)和0.45 g/kg组(130.40±33.20)中均显著高于对照组(100.30±19.40).MPP 0.22/kg组的NK细胞活性对数转换值(1.672±0.142)比对照组(1.392±0.182)明显升高.CD4+T辅助细胞(Th细胞)百分比在MPP 0.22 g/kg组(32.84±3.776)%和0.45 g/kg组(32.42±3.507)%中均显著高于对照组(25.06±0.354)%.血清IL-2浓度在MPP 0.22 g/kg组181.06 pg/ml、0.45 g/kg组94.84 pg/ml和1.35 g/kg 102.61 pg/ml中均显著高于对照组0.50 pg/ml;血清IL-5浓度在MPP 0.22 g/kg组38.31 pg/ml中显著高于对照组0.50 pg/ml.结论 MPP具有增强小鼠免疫功能的作用,可能通过增强Th细胞功能以及刺激细胞因子分泌而实现.     

铀矿尘对RAW 264.7细胞的氧化损伤作用

目的 探讨铀矿尘作用于小鼠RAW 264.7细胞一定时间后羟自由基(·OH)、过氧化氢(H2O2)及丙二醛(MDA)含量的变化.方法 用120 μg/ml的铀矿尘混悬液作用于小鼠RAW264.7细胞,分别在作用2、4、8、16、24和32 h后,采用噻唑蓝比色法(MTT法)检测RAW264.7细胞存活率；HE染色镜下观察细胞形态学变化；比色法测定细胞上清液中·OH、H2O2及MDA含量的改变.结果 铀矿尘作用于RAW264.7细胞2、4、8、16、24、32 h后,可见铀矿尘对RAW264.7细胞的增殖有明显抑制作用,染尘32 h后细胞存活率仅有(28.37±3.3)％；铀矿尘在作用于RAW264.7细胞16、24、32 h后,镜下可见梭型或不规则型细胞、多核细胞明显增加,细胞胞质缺失,胞核外露和染色变浅,细胞数目明显减少；铀矿尘处理的细胞上清液中·OH、H2O2及MDA在染尘后24 h达到峰值,分别为(94.05±4.72) U/ml、(68.83±4.34) mmol/L、(5.67±0.29) nmol/ml,与对照组比较,差异有统计学意义(P＜0.01).结论 铀矿尘可明显抑制RAW264.7细胞的增殖作用,导致细胞死亡数量增多.可引起细胞上清液中·OH、H2O2及MDA含量增高,对RAW264.7细胞具有氧化损伤作用.     

光气染毒对小鼠肺Ⅱ型细胞凋亡及血管内皮生长因子的影响

目的　观察光气致肺水肿小鼠肺Ⅱ型细胞发生凋亡情况和血清、肺脏的血管内皮生长因子 (VEGF)、VEGF受体 (Flt1)的变化及肺脏VEGFmRNA的表达。方法　 2 6只二级BALB C小鼠 ,雄性 ,随机分为 2组 :对照组和染毒组 (各 13只 )。对照组小鼠以空气为对照 ,染毒组小鼠给予 11.9mg L剂量的光气 ,时间均为 5min ,染毒后 4h ,分离小鼠原代肺Ⅱ型细胞 ,电镜观察两组小鼠肺Ⅱ型细胞凋亡情况 ,酶联免疫法测定血清和肺脏的VEGF、Flt1的含量及反转录PCR法测定肺脏VEGFmRNA的表达。结果　电镜显示光气染毒肺水肿小鼠原代肺Ⅱ型细胞出现凋亡小体 ;染毒小鼠血清VEGF和肺脏的VEGF、Flt1含量 [(134.0 7± 12 0 .2 6 )、(4 77.76± 98.0 6 )、(12 818.4 8± 2 30 4 .15 )pg ml]明显低于对照组 [(4 4 5 .5 7± 173.30 )、(10 2 6 .87± 4 74 .5 6 )、(2 1976 .5 1± 74 2 1.0 1)pg ml],差异有显著性 (P <0 .0 5 ) ;染毒小鼠血清Flt1含量 [(2 36 9.5 6± 381.70 )pg ml]明显高于对照组 [(1898.0 0± 4 5 3.6 9)pg ml],差异有显著性 (P <0 .0 5 ) ;染毒小鼠肺脏VEGFmRNA表达降低。结论　光气经呼吸道染毒可引起肺水肿小鼠原代肺Ⅱ型细胞发生凋亡 ,使血清VEGF和肺脏VEGF、Flt1降低及肺脏VEGFmRNA表达降低。     

丙烯腈对小鼠肺成纤维细胞增殖分化的影响

目的 研究丙烯腈(ACN)对小鼠肺成纤维细胞增殖分化的影响.方法 将ICR小鼠肺成纤维细胞纯化后进行细胞培养,加入二甲亚砜和浓度分别为0.01、0.5、1.0、10.0、50.0、100.0、200.0μg/ml的ACN,作为对照组和染毒组,每组10个平行样.从细胞形态学角度,通过细胞计数,观察细胞生长与分化的过程,同时测定蛋白质含量、丙二醛(MDA)含量和超氧化物歧化酶(SOD)活力.结果 浓度为0.01、0.5、1.0、10.0μg/ml的ACN对小鼠肺成纤维细胞生长无抑制作用,而浓度达到50.0、100.0、200.0μg/ml时,小鼠肺成纤维细胞的增殖和分化明显受到抑制,集落形成率明显减少,细胞体积变小,且随着ACN浓度的加大,其抑制作用增大.当ACN剂量为50.0、100.0、200.0μg/ml时,小鼠肺成纤维细胞相对蛋白质含量低于对照组(P＜0.05).当ACN剂量为10.0、50.0、100.0、200.0μg/ml时,小鼠肺成纤维细胞MDA的含量高于对照组(P＜0.01).当ACN剂量为10.0、50.0、100.0、200.0μg/ml时,小鼠肺成纤维细胞SOD活力低于对照组(P＜0.05).结论 ACN能抑制小鼠肺成纤维细胞增殖和分化,可能与其能抑制蛋白质合成,并引起脂质过氧化有关.     

Calcium intake in the elderly: validation of a dietary questionnaire

Epidemiological studies of calcium and osteoporosis have been hampered by the lack of a suitable tool for assessing calcium intake. This report describes a new frequency and amount questionnaire for measuring present and past calcium intake in the elderly. The validity of the questionnaire was tested against two commonly used standards of dietary assessment, five-day duplicate diets and seven-day weighed dietary inventories. The resulting correlation coefficients were, respectively, r = 0.76 and r = 0.69, while that for repeatability was r = 0.84. Furthermore, the questionnaire categorized subjects into thirds of the distribution of intake with almost no gross misclassification. It is suggested that the present findings may be extended to the majority of normal, healthy elderly subjects, implying wide application for the questionnaire in the assessment of calcium intake in the elderly.     

The human drama of genetics: 'hard' and 'soft' media representations of inherited breast cancer

This paper examines media coverage of 'breast cancer genetics', and explores its implications for public understanding. We present a content analysis of coverage in British newspapers and look at a variety of popular forms, including women's magazines, television soap opera and radio drama. Genetic/inherited risk receives a great deal of coverage across a wide range of media formats and outlets. Much of this attention has focused on individuals from 'high risk families' and dilemmas around prophylactic mastectomies. Through examining media coverage, combined with interviews with media personnel and their sources, we show why this story proved so attractive to the media and highlight the different production values which influence coverage. Finally, we introduce preliminary findings from focus group discussions to demonstrate how such 'human interest' framing has engaged audience attention and influenced public understandings. The paper concludes by highlighting the implications for analysing, predicting, and engaging with, media representations of science.     

Worker education in the primary prevention of occupational dermatoses

This paper reports the evaluation of a skin care education programmeconducted on a fine chemicals manufacturing site where over1,000 employees are located. Approximately 60% are involvedin chemical manufacture. Over a 12 month period production staffreceived training in prevention of occupational dermatoses linkedto a site-wide poster initiative. The incidence of new casesof occupational dermatoses fell from 0.055 (70 cases in 1,277employees) to 0.021 (27 cases in 1,277 employees) before andafter the intervention respectively (p<0.0001). After otherfactors such as chemicals handled, observer bias and changesin reporting related to socioeconomic climate were taken intoaccount it is concluded that this study demonstrates the importanceof worker education as a tool for primary prevention of disease.Training materials such as video and poster presentations maybe effectively used in the chemical manufacturing industry asan adjunct to prevention and control of exposure to substanceshazardous to the skin. Such methods may also be used in otherindustries where there are significant risks of dermatoses.     

Regional Variation in Travel-related Illness acquired in Africa,March 1997–May 2011

To understand geographic variation in travel-related illness acquired in distinct African regions, we used the GeoSentinel Surveillance Network database to analyze records for 16,893 ill travelers returning from Africa over a 14-year period. Travelers to northern Africa most commonly reported gastrointestinal illnesses and dog bites. Febrile illnesses were more common in travelers returning from sub-Saharan countries. Eleven travelers died, 9 of malaria; these deaths occurred mainly among male business travelers to sub-Saharan Africa. The profile of illness varied substantially by region: malaria predominated in travelers returning from Central and Western Africa; schistosomiasis, strongyloidiasis, and dengue from Eastern and Western Africa; and loaisis from Central Africa. There were few reports of vaccine-preventable infections, HIV infection, and tuberculosis. Geographic profiling of illness acquired during travel to Africa guides targeted pretravel advice, expedites diagnosis in ill returning travelers, and may influence destination choices in tourism.     

Self-reported health problems among Swedish miners one year after unemployment

Unemployment is considered to be a public health concern sincedeterioration in the health of the unemployed is often anticipated.However, for some groups, such as miners, unemployment mightimprove health due to a cessation of potentially harmful occupationalexposures. This study evaluates the health of 79 miners in oneSwedish iron-ore mine, and 226 age-matched controls from thegeneral population, during one year after the closure of themine. The participants received a questionnaire regarding medicalhistory and subjective symptoms at the beginning of the studyperiod, and after one year. Statistically significant negativeeffects on self-reported health attributable to unemploymentwere not found, although neuropsychiatric symptoms were morecommon among the unemployed miners. The miners reported a statisticallysignificant improvement in grip force (p=0.031). They had asignificantly higher prevalence of symptoms associated withmining related exposures when compared with the population controls;pain in the upper extremities [relative risk (RR)=2.27, 95%confidence interval (Cl)=1.44–3.59), back pain (RR=1.84;Cl=1.237–2.75), vasospastic disease of the fingers (RR=2.05;Cl=1.18–3.57) and obstructive respiratory symptoms (attacksof dyspnea and wheezing: RR=3.67; Cl=1.167–11.6).     

Excès de cas humains et animaux de tularémie en France au cours de l’hiver 2007–2008 : émergence ou phénomène isolé ?

Context

Tularemia is a zoonosis affecting humans and hares in France. We describe the results of surveillance in both species, in 2007 and 2008.

Methods

Human tularemia cases are mandatorily notifiable in France since 2003. In hares, surveillance relies on volunteer hunter associations in all districts of the country. Data from mandatory reports and volunteer surveillance in 2007/2008 were analyzed and compared with previous results.

Results

In 2007/2008, 144 cases were reported in humans and 117 cases in hares. This was a 100% increase compared to previous years. Human cases differed from those of previous years only by the frequency of contact with breeding animals. Human cases without any documented risk exposure were also more frequent.

Conclusion

An increase of tularemia cases occurred in 2007/2008 in both species. Complementary studies are needed to identify the species reservoir in France to understand the causes of this peak of cases.     

深圳公立医院管理体制改革制度设计

深圳公立医院管理体制改革实行政事分开、管办分开,在理事会架构下按法定机构模式组建市医管中心,落实公立医院运营管理自主权.作者从当前公立医院管理体制的弊端入手,介绍了深圳市进行公立医院管理体制改革的基本思路及改革方案设计的主要举措,深入剖析了的改革方案的特点,并对改革效果进行了预测.     

Effects of nitrogen dioxide on red blood cells of rats: Changes in components of red cell membranes during in vivo exposure to NO2

Red cell membranes, prepared from red blood cells of rats exposed to 4, 10, or 20 ppm nitrogen dioxide (NO₂) for 1 to 10 days, were examined for evidence of changes in membrane components. Appreciable changes were not found in contents of phospholipid and cholesterol during exposure to 10 ppm NO₂. By contrast, protein content altered with the time of exposure. Moreover, changes in protein composition were observed by employing sodium dodecyl sulfate — polyacrylamide gel electrophoresis. Twenty-four-hour exposure to NO₂ at the concentration above 10 ppm resulted in a marked increase in the percentage of lysophosphatidylethanolamine (LysoPE) to the total phospholipids. The prolonged exposure to 10 ppm NO₂ gave rise to a further increase in LysoPE, whereas the percentage of phosphatidylethanolamine (PE) showed a gradual decrease. A 1-day exposure to 4.0 ppm NO₂ also caused an increase in sialic acid content and decreases in those of PE and hexose. In addition to contents of these components the percentage of LysoPE increased 5 days after exposure and the elevated values were maintained up to the end of exposure period. These results demonstrate that red blood cells in circulation exhibit different membrane properties in terms of lipid and carbohydrate composition during 10 days of exposure to 4.0 ppm NO₂.     

The design of hazard risk assessment matrices for ranking occupational health risks and their application in mining and minerals processing

Two hazard risk assessment matrices for the ranking of occupational health risks are described. The qualitative matrix uses qualitative measures of probability and consequence to determine risk assessment codes for hazard-disease combinations. A walk-through survey of an underground metalliferous mine and concentrator is used to demonstrate how the qualitative matrix can be applied to determine priorities for the control of occupational health hazards. The semi-quantitative matrix uses attributable risk as a quantitative measure of probability and uses qualitative measures of consequence. A practical application of this matrix is the determination of occupational health priorities using existing epidemiological studies. Calculated attributable risks from epidemiological studies of hazard-disease combinations in mining and minerals processing are used as examples. These historic response data do not reflect the risks associated with current exposures. A method using current exposure data, known exposure-response relationships and the semi-quantitative matrix is proposed for more accurate and current risk rankings.