Pulmonary vascular responses to inhalation anaesthesia in isolated dog lungs

To study the mechanisms of action of four inhalation anaesthetics (diethyl ether, halothane, methoxyflurane, and nitrogen monoxide) upon the pulmonary circulation, the authors carried out 45 experiments in isolated, perfused and ventilated canine lungs. The effects of the anaesthetics were studied at 1) normotonic perfusion, 2) enhanced pulmonary blood flow, 3) microembolism-induced pulmonary hypertension. In the first two-experimental series, no effects of the test anaesthetics on the pulmonary vascular responses became manifest; at microembolism-induced pulmonary hypertension, halothane lowered the pulmonary vascular resistance, whereas diethyl ether stabilized the elevated vascular tone. Methoxyflurane and nitrogen monoxide had no marked effects on the pulmonary vascular responses. On the basis of their experiences and of data published in the literature the authors conclude that there exist regional mechanisms of action of anaesthetics on the lung vessels, activated by the release or action of mediators.     

Chamber exposures of children to mixed ozone, sulfur dioxide, and sulfuric acid

To help assess acute health effects of summer air pollution in the eastern United States, we simulated ambient "acid summer haze" as closely as was practical in a laboratory chamber. We exposed young volunteers who were thought to be sensitive to this pollutant mixture on the basis of previous epidemiologic evidence. Specifically, we exposed 41 subjects aged 9-12 y to mixed ozone (0.10 ppm), sulfur dioxide (0.10 ppm), and 0.6-microm sulfuric acid aerosol (100 +/- 40 microg/m3, mean +/- standard deviation) for 4 h, during which there was intermittent exercise. Fifteen subjects were healthy, and 26 had allergy or mild asthma. The entire group responded nonsignificantly (p > .05) to pollution exposure (relative to clean air), as determined by spirometry, symptoms, and overall discomfort level during exercise. Subjects with allergy/asthma showed a positive association (p = .01) between symptoms and acid dose; in healthy subjects, that association was negative (p = .08). In these chamber-exposure studies, we noted less of an effect than was reported in previous epidemiologic studies of children exposed to ambient "acid summer haze."     

Effects in rats and guinea pigs of short-term exposures to sulfuric acid mist, ozone, and their combination

Ozone and the oxides of sulfur are common environmental pollutants. The acute pulmonary lesions caused by ozone and sulfuric acid mist in rats and guinea pigs have been characterized. Rats are not affected by sulfuric acid mist in concentrations up to 100 mg/m3 except for reduced body weight at the higher doses. A true alveolitis develops in guinea pigs exposed to more than 20 mg/m3 sulfuric acid mist. The ozone lesion is primarily confined to the terminal bronchioles and proximal alveoli. In combination studies with up to 2 ppm ozone and up to 10 mg/m3 sulfuric acid mist, the pulmonary lesion and lung/body weight data were essentially the same as in exposure to ozone alone, and the number of statistically significant synergistic effects in rats and guinea pigs was about what one would expect to observe by chance alone.     

Recombinant cytokines and pulmonary host defense

The recent discovery of several cytokines and their purification using recombinant DNA technology has uncovered their role as critical factors in pulmonary host defense. The importance of tumor necrosis factor, interferon-gamma, and granulocyte-colony stimulating factor in lung infections was first elucidated in animal models and has been confirmed with neutralization studies. This article reviews these three cytokines, their recent use in human subjects, and their potential use in the future.     

中和滴定法测定工业硫酸中硫酸含量的不确定度评定

通过中和滴定法对工业硫酸中硫酸含量的不确定度来源进行分析,对测量过程中的主要不确定度分量进行了评定,包括测量的重复性、称取硫酸的量、硫酸的摩尔质量、称取邻苯二甲酸氢钾的量、邻苯二甲酸氢钾的摩尔量、滴定硫酸耗用的氢氧化钠标准滴定溶液的体积、滴定邻苯二甲酸氢钾耗用的氢氧化钠标准滴定溶液的体积等,并得出中和滴定法测量工业硫酸中硫酸含量的扩展不确定度。     

Respiratory responses to repeated prolonged exposure to 0.12 ppm ozone

Repeated exposure to high concentrations of ozone results first in augmentation (typically on the second day) and then attenuation of pulmonary response in humans. To determine the effects of repeated prolonged low-concentration ozone exposure, we exposed 17 healthy nonsmoking male subjects to 0.12 ppm ozone for 6.6 h on 5 consecutive days. Subjects were also exposed once to filtered air. Volunteers exercised at a ventilation of approximately 39 L/min for 50 min of each hour during the exposure. Spirometry, plethysmography, and symptom responses were obtained before, during, and after each exposure. Nasal lavage and aerosol bolus dispersion were obtained before and after exposure. Spirometry decreased and symptoms increased on the first day. Responses were less on the second day compared with those on the first day, and they were absent compared with control values on the subsequent 3 days of ozone exposure. Percent change in FEV1 after ozone exposure compared with that after air exposure averaged -12.79, -8.73, -2.54, -0.6, +0.18% for Days 1 to 5 of ozone exposure, respectively. FEV1 responses ranged from a zero to 34% decrease on Days 1 and 2. After each exposure, we determined the ratio of SRaw after inhaling a fixed dose of methacholine to SRaw after inhaling saline aerosol, as an index of airway responsiveness. Airway responsiveness was significantly increased after each ozone exposure. The mean ratios were 2.22, 3.67, 4.55, 3.99, 3.24, and 3.74 for filtered air and ozone Days 1 to 5, respectively. Symptoms of cough and pain on deep inspiration increased significantly on ozone Day 1 only.(ABSTRACT TRUNCATED AT 250 WORDS)     

CD40 and its ligand in host defense

The genetic changes involved in the metastatic process of ovarian epithelial cancer remain undetermined. The expression of nm23, a putative metastasis-suppressor gene product, was assessed immunohistochemically in malignant and benign ovarian neoplasms, considering histology of tumors and clinical advancement of disease. Comparison of nm23 protein content in tissue sections and respective cyst and/or ascitic fluid cells was also performed. Significant heterogeneity of nm23 immunostaining was observed, and no correlation with histological subtype of ovarian carcinoma was found. Expression of nm23 was higher in carcinomas compared with benign tumors. A significant trend to have a higher nm23 reactivity in ascitic fluid cells vs. primary tumors was observed. Our results indicate that the increase of nm23 reactivity is activated in the early stages of the disease and that the progression of ovarian carcinoma is accompanied by overexpression of nm23 protein. Our observations did not confirm the postulated role of nm23 as a suppressor gene in ovarian cancer.     

高氟洗涤酸对硫酸净化系统的危害及处理

针对韶关冶炼厂硫酸系统循环洗涤液中含氟高对塔体及设备造成严重腐蚀的问题，采用石灰乳中和混凝法在低pH值下进行处理，达到了开路除氟的目的。     

Extraction kinetics of alunite in sulfuric acid and hydrochloric acid

Extraction kinetics of alunite in sulfuric acid and hydrochloric acid were studied in a batch reactor. The effects of reaction temperature, acid concentration, particle size, calcination temperature, calcination time and KF/Al₂O₃ molar ratio on the extraction process were investigated. Experimental studies were carried out in the ranges of 35–95 °C for reaction temperature, 0.25–3.0 M for sulfuric acid, 0.5–0.6 M for hydrochloric acid, 76–182 μm for average particle size, 100–900 °C for calcination temperature, 15–60 min for calcination time and 0.15–0.90 for KF/Al₂O₃ molar ratio. The calcination temperature was the most important parameter affecting the extraction process followed by reaction temperature, particle size and acid concentration. Others had less effect. It was determined that the extraction process is controlled by diffusion through a product layer. The activation energies of the processes were found to be 19.1 and 18.5 kJ/mol for sulfuric acid and hydrochloric acid, respectively. The apparent rate constants were similar for both acids and found to be a function of acid concentration as C^0.33 and particle size r^−0.8.     

Innate immunity, cytokines, and pulmonary host defense

Effective host defense against bacterial infection is dependent on the activation and recruitment of phagocytic cells. The initiation, maintenance, and resolution of this inflammatory response in the setting of bacterial pneumonia is dependent on the expression of cytokines. As the complexities of the host-pathogen interaction are further dissected and unraveled, immunologic manipulation of cytokine expression will likely become an important adjuvant therapy in the treatment of serious lung infections.     

从硫酸烧渣中回收铅的试验研究

进行了H2SO4+NaCI溶液浸出低品位硫酸烧渣回收铅的试验研究.考察了氯盐浓度、酸度、液固比对铅漫出率的影响.在氯盐浓度300g/L、[H+]=1mol/L、液固比5:1的条件下,铅的浸出率迭97.28%.以CaO调节漫出后液pH值为9,沉淀中铅的品位达到60%.     

Leaching behavior of ilmenite with sulfuric acid

A study of the rate of dissolution of ilmenite in sulfuric acid solutions has been carried out. The effects of temperature, particle size, stirring speed, and concentration of sulfuric acid on the rate of dissolution of ilmenite has been investigated. Temperature range studied in this investigation was 88° to 115°C, and the Arrhenius activation energy was found to be 64.4 kJ (15.4 kcal) per mole. The rate of dissolution increased with concentration of sulfuric acid up to about 14 M sulfuric acid and decreased beyond this concentration. The maximum recovery at 14 M H₂SO₄ can be explained partially by the fact that H⁺ ion concentration peaks at about this concentration. Furthermore, reaction products, TiOSO₄ and FeSO₄, cover the surface of ilmenite when high concentrations of sulfuric acid are used, while these products are dissolved in water and removed from the surface when diluted sulfuric acid is involved. Based on the results obtained in this study, it can be concluded that the overall leaching of ilmenite with sulfuric acid at 88° to 115°C is described best by surface chemical reaction limiting with an order of 0.55 with respect to sulfuric acid concentration.     

Costimulation pathways in host immune responses to allogeneic hepatocytes

BACKGROUND: This study investigated the role of the CD28/B7 (blocked by CTLA4Ig) and CD40/CD40L (blocked by MR1) costimulation pathways on in vivo host T-cell- mediated immune responses to allogeneic hepatocytes. METHODS: Survival of allogeneic hepatocytes (H-2q) in C57BL/6 (H-2b) mice untreated or treated with MR1, CTLA4Ig, L6 (control fusion protein), or a combination of MR1 and CTLA4Ig fusion protein was determined. RESULTS: Median survival time for hepatocellular allografts was 10, 84, 10, 10, and 84 days in untreated (n= 10), MR1-treated (n=7) (P<.0001), CTLA4Ig-treated (n=7) (P=0.02), L6-treated (n=3) (P, not significant), and the combination of MR1- and CTLA4Ig-treated (n=6) (P=0.0003) groups, respectively. CONCLUSIONS: Host treatment with MR1, but not CTLA4Ig, prolonged hepatocellular allograft survival. These data suggest that CD28/B7 interactions appear relatively unimportant, whereas CD40/CD40L interactions provide critical costimulator signals for T-cell-dependent immune responses to allogeneic hepatocytes.     

Exaggerated responses to chlorine inhalation among persons with nonspecific airway hyperreactivity

Since it is unclear whether methotrexate and cytarabine are synergistic or antagonistic in the treatment of acute lymphoblastic leukemia, the Pediatric Oncology Group studied the prognostic significance of a potential interaction between these agents. RBC methotrexate concentrations were compared from 140 patients at lower risk of relapse randomized to two treatment groups: one receiving six methotrexate infusions with overlapping cytarabine; the other, six methotrexate infusions alone. Samples from 248 patients from all risk groups were studied to determine whether patients with extremely low RBC methotrexate concentrations had inferior outcomes. Among low-risk patients studied 3 weeks after the sixth infusion, median RBC methotrexate concentrations were 0.13 nmol/ml RBCs (n = 71) for the methotrexate-only group and 0.02 nmol/ml RBCs (n = 69) for the methotrexate/cytarabine-treated low-risk patients, P < 0.001 by the two-sided Wilcoxon test. For low- and high-risk patients receiving methotrexate/cytarabine infusions, event-free survival at 1 and 3 years after RBC sampling was 97 +/- 2% and 90 +/- 3% for patients with concentrations greater than the median, and 88 +/- 3% and 78 +/- 4% for those with concentrations at or below the median. Log rank comparisons of event-free survival in the first year and overall yielded P = 0.005 and P = 0.04, respectively. Cytarabine altered methotrexate pharmacology when the drugs were infused together. Patients whose levels were extremely low had an adverse prognosis. Although this study could not assess efficacy of the methotrexate/cytarabine combination, it appears that concurrent administration is not optimal.     

Determination of the association constant of sulfuric acid

The activities of HC1 and H₂SO₄ in aqueous solutions of HC1-H₂SO₄ and H₂SO₄-HC1O₄, respectively, were measured at 298 K by an electromotive force (emf) method. Using the activity data, the association constant,K*_{H 2SO 4} was calculated as a function of the effective ionic strength of the solution by a method similar to that proposed by Johnson and Pytkowicz. The association constant of H₂SO₄, which corresponds to the reciprocal value of the first ionization constant of H₂SO₄, decreased with an increase in the effective ionic strength and was correlated to the effective ionic strength,I _e (mol dm⁻³), as follows: logK*_{H 2SO 4} = 0.42 - 0.91I_e, 0 I_e1 The mean free activity coefficients of H₂SO₄ were calculated from the association constant of H₂SO₄ and were found to decrease with an increase in the effective ionic strength. Formerly Graduate Student, Department of Metallurgy, Kyoto University.     

HAZOP分析在硫磺制酸工程中的应用

概述了危险源及可操作性分析方法（HAZOP）,介绍了硫磺制酸工程的主要生产工艺,论述了硫磺制酸工程的HAZOP分析流程.硫磺制酸工程通过实施HAZOP分析,减少了详细设计错误,提高了自控系统的稳定性,保证了装置生产运行的安全性和可靠性.     

铁闪锌矿在硫酸浸出过程中的电化学行为

为研究铁闪锌矿氧化浸出机理,以人工合成铁闪锌矿的悬浮矿浆为研究对象,采用三电极体系对其在硫酸浸出过程中的电化学行为进行了研究.结果表明在铁闪锌矿浸出过程中有H₂S中间产物生成;通氧、元素硫分散剂以及氯离子引入浸出体系均能明显促进铁闪锌矿的电化学氧化;随硫酸浓度升高,铁闪锌矿的电化学氧化不断加强而闪锌矿的电化学氧化受抑.与闪锌矿相比,铁闪锌矿更易发生电化学氧化.在铁闪锌矿硫酸浸出过程中,其电化学氧化作用不容忽视.