Ambient air pollution and human performance: Contemporaneous and acclimatization effects of ozone exposure on athletic performance

This paper utilizes a unique dataset of competitive outcomes from intercollegiate track and field competition to identify the relationship between recent ambient pollution exposure histories and human performance among a young and fit population in a diverse range of physically demanding "tasks". I find that higher contemporaneous ozone levels are associated with poorer performances in events that heavily tax the respiratory system. This is the case despite the low exposure levels observed in the studied sample, which are similar to those regularly experienced across the developed world. Such negative performance effects imply that observed ozone exposures are leading to physiological harm, which can be expected to negatively impact economic outcomes through both health and productivity channels. Leveraging the unique structure of the data— which includes location information for competitions and home institutions— I also identify an acclimatization effect whereby recent exposure to higher ozone levels serves to reduce the negative effects of contemporaneous exposure. This finding underscores the importance of regulating peak ozone levels rather than only mean concentrations, as spikes in ambient ozone levels can be particularly damaging to exposed populations.     

Ambient ozone and emergency department visits for cellulitis

Objectives were to assess and estimate an association between exposure to ground-level ozone and emergency department (ED) visits for cellulitis. All ED visits for cellulitis in Edmonton, Canada, in the period April 1992-March 2002 (N = 69,547) were examined. Case-crossover design was applied to estimate odds ratio (OR, and 95% confidence interval) per one interquartile range (IQR) increase in ozone concentration (IQR = 14.0 ppb). Delay of ED visit relating to exposure was probed using 0- to 5-day exposure lags. For all patients in the all months (January-December) and lags 0 to 2 days, OR = 1.05 (1.02, 1.07). For male patients during the cold months (October-March): OR = 1.05 (1.02, 1.09) for lags 0 and 2 and OR = 1.06 (1.02, 1.10) for lag 3. For female patients in the warm months (April-September): OR = 1.12 (1.06, 1.18) for lags 1 and 2. Cellulitis developing on uncovered (more exposed) skin was analyzed separately, observed effects being stronger. Cellulitis may be associated with exposure to ambient ground level ozone; the exposure may facilitate cellulitis infection and aggravate acute symptoms.     

Cyclic AMP and GMP levels in thymocytes and splenic T and B lymphocytes in protein deprived rats.

Cyclic nucleotide levels were determined in thymocytes and in splenic T and B lymphocytes separated by nylon wool filtration. In control rats, thymocytes contained less cAMP and cGMP than splenic T cells. The level of cGMP was lower, and consequently cAMP:cGMP ratio was higher in splenic B than in T cells. Protein deprivation increased the nucleotide ratios in both T and B splenic lymphocytes; this effects was due to a decrease in the cGMP levels in the case of the T cells and to an increase in the cAMP levels in the B cells. These data could be related to the reduced mitotic activity of the splenic lymphocytes. However, the nylon-nonadherent thmyocytes of protein deprived rats paradoxically displayed increased cGMP contents without changes in the cAMP levels, despite the drop in their proliferative potential. The impairment of cyclic nucleotide metabolism may intervene in the immunological disturbances due to protein malnutrition.     

Specific effects of protein deprivation on thymus and spleen; rates of protein synthesis in lymphocytes derived from thymus,spleen and bone marrow

Young adult male rats (body weight 90 g) were fed for 6 days a low protein (3% casein) diet and compared with rats fed a diet optimal in protein (20% casein). To study the dietary effects of protein, but not energy deficiency, intake of energy per unit body weight was kept constant. Wet weights and DNA content of thymus and spleen organs decreased in the low protein diet group. The in vitro incorporation of 14C-leucine into protein by isolated ribosomes was diminished in thymus by 22% and in spleen by 33% per mg of ribosomal RNA, and per mg of DNA by 43% in thymus and 48% in spleen. Lymphocytes were separated by Ficoll gradients. As compared with controls lymphocyte number from thymus decreased by 90%, that of spleen by 43% and of bone marrow by 20%. The rates of protein synthesis were significantly reduced after protein restriction in lymphocytes of the 3 organs. The strongest effects on the rates of protein synthesis were observed in bone marrow. Reduction in lymphocytes recovered was most pronounced in thymus. The results indicate that malnutrition by protein, but not energy deficiency, elicites specific effects on the 3 lymphocyte producing or containing organs studied.     

Ambient ozone and emergency department visits due to lower respiratory condition

Objectives

Ambient ozone (O₃) exposure is associated with a variety of health conditions. The objective of this study was to examine the effect of increased daily concentrations of ozone on emergency department (ED) visits due to lower respiratory diseases (LRD), such as acute or chronic bronchitis, in Edmonton, Canada.

Materials and Methods

Data concerning 10 years (1992–2002) were obtained from 5 Edmonton hospital Emergency Departments. Odds ratios (ORs) for ED visits associated with the increased ozone levels were calculated employing a case-crossover technique with a time-stratified strategy to define controls. In the constructed conditional logistic regression models, adjustments were made for daily number of influenza ED visits and weather variables using natural splines. ORs and their 95% confidence intervals (95% CI) were reported in relation to an increase in the interquartile range (IQR = 17.9 ppb) of the ground-level ozone.

Results

Overall, 48 252 ED visits due to LRD were identified, of which 53% were made by males. The presentations peaked in December (12%) and February (11.7%) and were the lowest in August (5.6%). Positive and statistically significant results were obtained for acute bronchitis: for same day (OR = 1.09, 95% CI: 1.05–1.13, lag 0) and for lag 2, lag 3–7 and 9 days; for chronic bronchitis: for lag 6, 7, and lag 9 days (OR = 1.11, 95% CI: 1.05–1.18, lag 9). For all ED visits for LRD, lag 0, lag 1, and lag 3–9 days showed positive and statistically significant associations (OR = 1.06, 95% CI: 1.03–1.09, lag 0).

Conclusions

These findings support the hypothesis concerning positive associations between ozone and the ED visits due to LRD.     

The effect of ozone on human cellular and humoral immunity: characterization of T and B lymphocytes by rosette formation.

Eight healthy male subjects were exposed to 784 μg/m³ (0.4 ppm) of ozone for 4 hours in an environmentally controlled exposure chamber. Peripheral blood samples were taken before and after air and ozone exposures and again at 72 hours and 2 weeks. These blood samples were examined for the percentages of rosette-forming T and B lymphocytes. No statistically significant depressions in T-lymphocyte rosette formation with sheep erythrocytes were found following exposure to air or ozone. The ability of B lymphocytes to form rosettes with sensitized human erythrocytes was depressed following ozone exposure. These results suggest that surface receptors and/or the cell membranes of peripheral blood B lymphocytes may be temporarily altered following short-term exposure to ozone.     

T、B淋巴细胞及细胞因子在三氯乙烯诱发过敏反应中的作用

目的利用三氯乙烯(TCE)染毒的小鼠模型,研究T、B淋巴细胞及细胞因子在TCE诱发过敏反应中的作用。方法以皮肤接触同时结合吸入对12只小鼠进行致敏处理,6周后耳部涂抹TCE进行激发。以耳肿胀系数作为评价小鼠过敏反应的指标;分离脾细胞体外培养,采用噻唑蓝(MTT)法测定脾淋巴细胞抗原特异性增殖反应;酶联免疫吸附测定(ELISA)方法测定细胞培养上清液中IgG和白介素-4(IL-4)、γ型干扰素(IFN-γ)水平;应用流式细胞技术进行淋巴细胞亚群分析。结果TCE致敏组小鼠脾淋巴细胞加入TCE体外培养后,细胞存活率明显高于溶剂对照组[(79±10)%vs(63±11)%,P<0·05];细胞培养上清液中IgG水平(与二甲基亚砜对照孔比较的相对值)在两组间比较差异有显著性[(70±5%)vs(53±6)%,P<0·01]。流式细胞分析结果显示,TCE致敏组脾淋巴细胞与TCE共培养后,CD3 T细胞占总淋巴细胞的比例[(41·6±4·4)%]及CD4 /CD8 (2·1±0·6)与对照组比较[分别为(39·4±4·0)%和(2·3±0·9)],差异无显著性(P>0·05)。TCE致敏组小鼠激发时未见耳肿胀,然而TCE致敏组小鼠IFN-γ/IL-4比值(0·54±0·12)明显低于溶剂对照组(0·90±0·22,P<0·01)。结论TCE能够诱导T淋巴细胞的增殖活化,分泌Th2型细胞因子,并刺激B淋巴细胞分泌抗原特异性的IgG抗体。     

Zinc-deficient rats have fewer recent thymic emigrant (CD90+) T lymphocytes in spleen and blood

It has been hypothesized that increased expression of the signaling protein p56(lck) disrupts maturation of T lymphocytes, leading to the lymphopenia associated with dietary zinc deficiency and malnutrition. Our objective was to examine p56(lck) protein levels, flow cytometric markers of T cell development (CD4, CD8, TCRalphabeta, TCRgammadelta and CD90) and absolute cell numbers in thymus, spleen and blood of zinc-deficient (ZD), diet-restricted (DR) and control (CTL) rats. Recent thymic emigrant (CD90+) T lymphocytes were also investigated after dietary repletion. P56(lck) protein levels were one- to twofold greater in thymocytes than splenocytes, and ZD rats had more thymocyte p56(lck) protein than CTL rats. In the thymus and blood, the proportions of T lymphocyte subpopulations (CD4-CD8-, CD4+CD8+ and CD4+CD- or CD4-CD8+) were unchanged, except for a higher percentage of TCRalphabeta+CD-CD8+ thymocytes in ZD rats. The 15-29% fewer CD90+ T cells in the blood and spleen of ZD rats were reversed after dietary repletion for 7 and 23 d, respectively. In summary, T-cell numbers were proportional to thymus and spleen weights and unaltered per unit blood volume, despite elevated thymocyte p56(lck) protein in ZD rats. In zinc deficiency, the decreased percentages of CD90+ cells in the blood and spleen could adversely affect the T-cell repertoire.     

Activation of spleen lymphocytes by plasmid DNA

Plasmid pUC19 DNA was shown to stimulate in vitro proliferation of CBA mouse splenocytes in a dose-dependent manner. Simultaneous treatment of the cells with the plasmid DNA and Con A or LPS produced an additive effect, while PMA acted synergistically with DNA. Monovalent Fab fragments of rabbit anti-mouse Ig (RAMIg) antibodies significantly inhibited plasmid DNA-induced polyclonal lymphocyte activation suggesting the involvement of Ig receptors in this process. Affinity modification of lymphocytes membrane-cytosole proteins with a 32P-labeled alkylating oligonucleotide derivative resulted in labeling of 67-82 and 23 kDa polypeptides corresponding to IgD and IgM heavy and light chains respectively. The immunoglobulin nature of the 82 and 23 kDa oligonucleotide-binding polypeptides was confirmed by immunoprecipitation with RAMIg antibodies.     

乙醇醛对小鼠脾淋巴细胞DNA损伤作用的研究

目的　观察乙醇醛对DNA的损伤作用。方法　采用单细胞凝胶电泳 (SCGE)技术检测不同浓度乙醇醛对小鼠脾淋巴细胞DNA的损伤程度。结果　当乙醇醛浓度为 0 0 1mmol L时即能引起脾淋巴细胞DNA链断裂损伤 ,DNA损伤率为 8% ,DNA平均迁移距离为 ( 14 32± 2 84 ) μm。随着乙醇醛浓度的升高DNA损伤率和DNA平均迁移距离均以浓度依赖方式增加。结论　乙醇醛可引起细胞DNA损伤     

Effects of L-arginine on the proliferation of T lymphocyte subpopulations

BACKGROUND: Dietary supplementation of L-arginine as a mechanism to enhance cellular immune response (T lymphocytes), has slowly gained approval, and appears especially important during critical illness. Despite its clinical use, little is known as to the direct effects of L-arginine on the different T lymphocyte subpopulations. METHODS: Lymphocytes were harvested from spleens of C57 B1/6 mice, and proliferation was induced with anti-CD3 in the presence of different concentrations of L-arginine ranging from 0 to 1000 micromol/L. Flow cytometry was used to evaluate the effect of L-arginine on T lymphocyte subpopulations. Interleukin-2 production was measured by ELISA and gene expression by RT-PCR. RESULTS: L-Arginine at or greater than 100 micromol/L significantly enhanced anti-CD3 stimulated T lymphocyte proliferation (p = .01). L-Arginine was essential for adequate T lymphocyte (CD3+) cellular maturation (p = .01). Proliferation of Helper T cells (CD4+) was not dependent on L-arginine. In contrast, Cytotoxic T cells (CD8+) showed a dose dependent proliferation in response to L-arginine (p = .01). Of the CD8+ cells, an increase in the CD45RA negative CD8 positive (memory) T cell subpopulation was observed with the addition of L-arginine. In addition, the number of cell surface CD8 receptors (CD8R) and CD3 receptors (CD3R) increased in the presence of L-arginine (p = .01, p = .04). Interleukin-2 receptor (IL-2R) expression was not up-regulated by L-arginine. L-Arginine modestly increased IL-2 production and had pronounced effects on its disappearance from the culture media (p < .0001). Interleukin-2 mRNA expression was not dependent on L-arginine. CONCLUSIONS: The requirements for L-arginine for the proliferation of CD3 stimulated T lymphocytes vary widely, and have to be taken into account when studying the mechanism of how L-arginine enhances cellular proliferation. L-Arginine may increase cellular proliferation by increasing specific receptor expression and the utilization of interleukin-2.     

不同锌营养状态对小鼠淋巴细胞相关免疫功能的影响

目的旨在观察不同锌营养状况对小鼠淋巴细胞相关免疫功能的影响。方法在锌耗竭期,分低锌组(DC)(饲料含锌5.2mgkg)、对饲组(PZ)和正常锌组(饲料含锌25.6mgkg)。继后的锌补充期,分低锌组(DC)、低锌正常组(DZNZ)和对饲自由组(PZNZ)。动态观察免疫功能相关指标如脾细胞数,淋巴细胞转化率,和刀豆蛋白A刺激的IL2的分泌情况。结果缺锌70天后可明显降低脾细胞数目,补锌22天后增加。缺锌可抑制脾T细胞的增殖反应,补锌后也有所上升。低锌组小鼠脾细胞分泌的IL2下降,补锌后可逐步恢复。结论锌可影响免疫系统的功能。IL2的变化较明显。     

乳腺癌术后化疗感染患者病原学特点及 T淋巴细胞水平

目的 探讨乳腺癌术后化疗感染患者病原学特点及白细胞计数(WBC)、T淋巴细胞水平变化。方法 选取2018年1月-2020年12月南阳市医学高等专科学校第一附属医院收治的203例乳腺癌术后化疗患者为研究对象,分析术后医院感染情况及病原菌分布,比较感染与非感染组患者外周血WBC和CD_3⁺、CD_4+、CD_4⁺、CD_8+、CD_8⁺ T淋巴细胞水平。结果 203例乳腺癌术后化疗患者,发生医院感染34例,感染率为16.75%。呼吸道、皮肤软组织和口腔黏膜感染占比较高,分别占44.12%、17.65%、14.71%。检出病原菌中革兰阴性菌占46.88%,革兰阳性菌占31.25%,真菌占21.88%。主要为铜绿假单胞菌、金黄色葡萄球菌和大肠埃希菌。感染组和非感染组患者年龄、TNM分期、化疗周期及联合放疗比较差异有统计学意义(P<0.05)。感染组患者WBC、CD_3+ T淋巴细胞水平。结果 203例乳腺癌术后化疗患者,发生医院感染34例,感染率为16.75%。呼吸道、皮肤软组织和口腔黏膜感染占比较高,分别占44.12%、17.65%、14.71%。检出病原菌中革兰阴性菌占46.88%,革兰阳性菌占31.25%,真菌占21.88%。主要为铜绿假单胞菌、金黄色葡萄球菌和大肠埃希菌。感染组和非感染组患者年龄、TNM分期、化疗周期及联合放疗比较差异有统计学意义(P<0.05)。感染组患者WBC、CD_3⁺、CD_4+、CD_4⁺、CD_4+、CD_4⁺/CD_8+/CD_8⁺水平低于非感染组(P<0.05),而CD_8+水平低于非感染组(P<0.05),而CD_8⁺水平高于非感染组(P<0.05)。结论 乳腺癌术后化疗感染率较高,检出病原菌种类多样,临床应对化疗周期较长、联合放疗治疗的患者加强重视,合理监测WBC、T淋巴细胞水平,积极预防感染发生。     

Modifiers of short-term effects of ozone on mortality in eastern Massachusetts - A casecrossover analysis at individual level

Background  

Substantial epidemiological studies demonstrate associations between exposure to ambient ozone and mortality. A few studies simply examine the modification of this ozone effect by individual characteristics and socioeconomic status, but socioeconomic status was usually coded at the city level.     

Lymphocyte subpopulations in the thymus, lymph nodes and spleen of iron-deficient and rehabilitated mice

Three groups of weanling female mice were fed one of two iron-deficient diets (5 and 12 mg Fe/kg diet) or a normal diet (30 mg Fe/kg diet) for 6 wk. A control pair-fed group was included. Seven mice received the 5 mg Fe/kg diet for 6 wk, then were rehabilitated using the 30 mg Fe/kg diet for 10 d. Mice fed the 5 mg Fe/kg diet were moderately iron-deficient, as shown by indices of iron status. No significant differences were observed in thymus weight or in the proportion and number of thymocyte subsets in thymuses of anemic, moderately iron-deficient and control mice. Thymus weight was decreased in pair-fed mice. No significant difference was found in lymph node subsets. In the spleen of anemic mice, the proportions and total number of Thy-1+ splenocytes, CD4-8+ and CD4+8- cells were very low compared with control (P less than 0.01) and iron-deficient (P less than 0.02) mice. The decrease was not only observed for the percentage of subsets but also for the absolute number of cell subtypes per spleen. Thy-1+ splenocyte subpopulations were normalized after rehabilitation. These quantitative modifications could explain alterations in the blastogenic response of splenic lymphocytes described by other authors.     

母牛分支杆菌菌苗对矽肺结核患者周围血T淋巴细胞水平的影响

目的 了解母牛分支杆菌菌苗(微卡)对矽肺结核患者周围血淋巴细胞水平的影响,为矽肺结核患者提供一种免疫辅助治疗方法 .方法 将矽肺结核病人按年龄、病变期别等条件随机配对分为微卡使用组(治疗组)和不使用组(对照组).治疗组臀部肌内深部注射微卡22.5μg/次,每2周1次;对照组除不使用微卡外,其他结核化疗方案与治疗组相同.分别于治疗前、微卡使用1、2,4个月时抽血进行周围血T淋巴细胞等各项指标的分析研究.结果 与对照组比较,治疗组在微卡使用4个月时CD3、CD4水平明显高于对照组(P<0.05).治疗组自身前后比较,CD3、CD4平均水平有随使用微卡时间的延长而逐渐增高的趋势(P<0.01或O.05),至4个月时各项细胞免疫指标平均值基本恢复至正常水平.此外,治疗组CD3、CD4、CD8的异常率(%)有随治疗时间的延长而降低的趋势(P<0.05).治疗组治疗后胸片结核浸润性病变的吸收率明显高于对照组(P相似文献