Effects of ambient air pollution on symptom severity and medication use in children with asthma.

BACKGROUND: Exposure to air pollutants has been investigated as a possible cause of asthma attacks in children. OBJECTIVE: To investigate the short-term effects of air pollutants on a panel of 133 children with asthma who enrolled in the Childhood Asthma Management Program. METHODS: During screening, the children completed daily diary cards for an average of 58 days to indicate their medication use and asthma severity. We used ordinal logistic regression to compare the odds of a more serious relative to a less serious asthma attack, and we used a Poisson model to analyze medication use. In both analyses we accommodate dependence in the data and different periods of observation for study subjects. RESULTS: Our results indicate that a 10-microg/m3 increase in particulate matter less than or equal to 2.5 microm (PM2.5) lagged 1 day was associated with a 1.20 times increased odds of having a more serious asthma attack [95% confidence interval (CI), 1.05 to 1.37] and a 1.08-fold increase in medication use (95% CI, 1.01 to 1.15). A 10-microg/m3 increase in particulate matter less than or equal to 10 microm (PM10) increased the odds of a more serious asthma attack (odds ratio = 1.12; 95% CI, 1.04 to 1.22) and also increased medication use (relative risk = 1.05; 95% CI, 1.00 to 1.09). CONCLUSIONS: Increases in PM2.5 and PM10 are significantly associated with an increased risk of more severe asthma attacks and medication use in Seattle area children with asthma. We also found associations with carbon monoxide, but we believe that carbon monoxide is a marker for exposure to combustion byproducts.     

裂解汽油在ZSM-5沸石上的芳构化

采用连续流动反应装置,考察了裂解汽油在HZSM-5与金属元素改性的HZSM-5上的芳构化反应,发现锌改性后提高了液体产物中芳烃的收率。为了克服裂解汽油中含硫含焦杂质的影响,提出了获取芳烃的有效工艺:蒸馏除焦-加氢预脱硫-氢气氛下芳构化反应-冷凝产物。用氨吸附的程序升温脱附法,将催化剂的酸性质与其催化芳构化作用进行关联,认为Zn改性后的HZSM-5催化剂具有较温和的酸中心,可能是其芳构化高活性与高选择性的原因。     

颈椎脱位的闭合复位

1985年5月～1996年3月,我们经治34例单纯颈椎脱位患者,30例行Crutchfield颅骨牵引闭合复位,20例成功,占66.6％。在成功组中,牵引重量最大为18kg,无一例出现神经损害加重。不全瘫均有不同程度恢复。尸体头颅标本测定,Crutchfield颅骨牵引承受的最大抗拨出力为60.3kg,在治疗颈椎脱位时,颅骨牵引是安全有效的闭合复位方法。     

Role of endothelin in the pathogenesis of hypertension in spontaneously hypertensive and 2 kidneys 1 clip rats.

The plasma endothelin (ET) level in spontaneously hypertensive rats (SHR) and 2K1C hypertension animal models and its vasoconstrictive effect on renal and tail arteries were studied. The results demonstrated that there was no difference in plasma ET level between the hypertensive groups SHR, 2K1C, normotensive control groups Wistar Kyot (WKY) and Sprague Dawley (SD), while the vasoconstrictive effect of ET in SHR was more dominant than in WKY. The EC50 of the renal and tail arteries in SHR (0.8912 +/- 0.1662 x 10(-8) M, 0.6103 +/- 0.0878 x 10(-8) M) was apparently lower than that in WKY (1.77 +/- 0.2991 x 10(-8) M, 1.2267 +/- 0.2502 x 10(-8) M, P less than 0.05), but no difference was found in 2K1C and SD rats. The four groups of animals exhibited no difference of such effects as response to norepine-phrine (NA). The findings suggested that the increased arteriole sensitivity to ET be an important factor in the pathogenesis of hypertension in SHR.

     

Penetration of Schistosoma japonicum cercaria into host skin.

The anterior part of Schistosoma japonicum cercaria is a specialized head organ which can slightly stretch out and retract. There are three different types of large unicellular glands in cercarial body, consisting of one head gland, 2 pairs of pre- and 3 pairs of postacetabular glands. These glands differ in position, gross feature, histochemistry and functions. Both polysaccharase and protease activities are demonstrated in the secretions from these glands. Mode of cercarial penetration is described in detail and the penetration is effected by a combination of lytic secretions and mechanical movements. The schematic representation of the process of cercarial penetration is presented. The dynamic distributions of schistosomula in skin at different time intervals after skin penetration in various mammalian hosts are shown. Some newly transformed schistosomula die while penetrating into the skin of 7 mammalian species and the mortality rate varies with the host species, and that can also be affected by the age of cercariae following emergence from the snail. Some physiological aspects between cercariae and newly transformed schistosomula are compared. In contrast to cercariae, schistosomula are saline-adapted and water-intolerant. They were modified histochemically and antigenically.

     

The pulmonary effects of ozone and nitrogen dioxide alone and combined in healthy and asthmatic adolescent subjects

Separate exposures to 0.12 ppm ozone (O3) or 0.18 ppm nitrogen dioxide (NO2) have not demonstrated consistent changes in pulmonary function in adolescent subjects. However, in polluted urban air, O3 and NO2 occur in combination. Therefore, this project was designed to investigate the pulmonary effects of combined O3 and NO2 exposures during intermittent exercise in adolescent subjects. Twelve healthy and twelve well-characterized asthmatic adolescent subjects were exposed randomly to clean air or 0.12 ppm O3 and 0.30 ppm NO2 alone or in combination during 60 minutes of intermittent moderate exercise (32.5 1/min). The inhalation exposures were carried out while the subjects breathed on a rubber mouthpiece with nose clips in place. The following pulmonary functional values were measured before and after exposure: peak flow, total respiratory resistance, maximal flow at 50 and 75 percent of expired vital capacity, forced expiratory volume in one second and forced vital capacity (FVC). Statistical significance of pulmonary function changes was tested by analysis of covariance for repeated measures. After exposure to 0.12 ppm O3 a significant decrease was seen in maximal flow at 50% of FVC in asthmatic subjects. After exposure to 0.30 ppm NO2 a significant decrease was seen in FVC also in the asthmatic subjects. One possible explanation for these changes is the multiple comparison effect. No significant changes in any parameters were seen in the asthmatic subjects after the combined O3-NO2 exposure or in the healthy subjects after any of the exposures.     

Inhibition kinetics of human kidney aldose and aldehyde reductases by aldose reductase inhibitors

Kinetic patterns of inhibition of homogenous human kidney aldose reductase (AR, EC 1.1.1.21) and aldehyde reductase II (AR II, EC 1.1.1.19) by statil, ICI 105552 [1-(3,4-dichlorobenzyl)-3-methyl-1,2-dihydro-2-oxoquinol-4-yl acetic acid], tolrestat, alrestatin, chromone carboxylic acid (CCA), quercetin, phenobarbital and sorbinil were studied. On the basis of the kinetic nature of inhibition, the inhibitors were classified into four distinct categories. For aldose reductase, sorbinil and phenobarbital were noncompetitive (NC; category I) and CCA and alrestatin were uncompetitive (UC; category II) to both the aldehyde substrate and NADPH. Quercetin and ICI 105552 were NC to the aldehyde and UC to NADPH (category III) and tolrestat and statil were UC to the aldehyde and NC to NADPH (category IV). For AR II, sorbinil and alrestatin were category I inhibitors, ICI 105552 and statil belong to category II, phenobarbital, tolrestat and CCA to category III, and quercetin to category IV. To determine the specificity of inhibition, the ratios of the inhibition constants (Kii) for AR and AR II were calculated. A lower ratio indicates greater specificity. With aldehyde as the varied substrate the specificity ratios were: statil less than ICI 105552 less than alrestatin less than tolrestat less than quercetin less than CCA less than sorbinil less than phenobarbital, and with NADPH as the varied substrate, ICI 105552 less than statil less than alrestatin less than tolrestat less than quercetin less than CCA less than sorbinil less than phenobarbital. For AR, double-inhibition plots generated for one inhibitor from each kinetic category versus sorbinil showed that AR inhibitors of categories I-III bind to the same site on the protein molecule as sorbinil. However, tolrestat seemed to bind to a site different from the sorbinil binding site. For AR II, inhibitors from all the four categories appeared to bind to the same inhibitor binding site.     

A binding site peptide fragment of the nicotinic acetylcholine receptor. Sequence-specific assignment of 1H-NMR resonances in the dodecamer alpha 185-196

The total sequence-specific 1H assignment for the alpha 185-peptide was accomplished by analysis of COSY spectra along with spin-decoupling and confirmatory NOE difference experiments. Some ambiguities in the assignments were successfully addressed utilizing additional peptides with selective amino acid substitutions. The chemical shifts of several of the C alpha H resonances, along with evidence for a slowly exchanging amide at Thr-191 suggest that the alpha 185-peptide may contain a certain amount of non-random coil structure. The role of any such ordered structure in the mechanism of binding to alpha-bungarotoxin remains to be determined. The assignment of the peptide 1H resonances will facilitate the analysis and identification of chemical shift perturbations observed upon formation of the complex between alpha-bungarotoxin and the alpha 185-peptide [7].     

Protective Effects of Antioxidants Against Uraemia-Induced Lipid Peroxidation and Glutathione Depletion in Humans

Abstract: The effects of uraemias and antioxidant therapy for 40 days with vitamin A, vitamin C and vitamin E on blood and erythrocyte sulfhydryl (glutathione, GSH) content and on erythrocyte glutathione-S transferase (GST), glutathione reductase (GSR) and glutathione peroxidase activities were studied in six uraemic patients maintained on haemodialysis. In addition, the effect of antioxidant therapy on erythrocyte lipid peroxidation was determined, and erythrocyte haemoglobin content was measured. Uraemic patients in dialysis exhibited significant decreases in blood and erythrocyte GSH content as well as significant decreases in the activities of GST, GSR and GSH-peroxidase relative to control subjects. Furthermore, the uraemic patients had elevated erythrocyte malondialdehyde levels. Blood and erythrocyte GSH content from uraemic patients was significantly elevated after 20 days of antioxidant treatment and remained elevated thereafter throughout the remaining 20 days of the study (130% and 173%, respectively). Antioxidant therapy also produced significant increases in GSR and GSH-peroxidase activities after 20 days of treatment which remained relatively constant thereafter. No significant change in GST activity was observed. Erythrocyte malondialdehyde levels, as an index of oxidative tissue damage, exhibited a significant decrease (70%) in the patients after 40 days of antioxidant therapy. A gradual increase in erythrocyte haemoglobin content was observed following treatment of the uraemic subjects (45% at day 40). The results suggest that antioxidant therapy may protect against oxidative stress associated with uraemia.