UMLS:C0847097 - FACTA Search

Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0847097 (acidity)
15,165 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Acute effects of winter-type air pollution characterized by high levels of SO2, moderate levels of particles, and low acidity were studied. A panel of 155 asthmatic children and 102 adults with a history of asthma from the former German Democratic Republic cities of Erfurt and Welmar and from the Czech Republic city of Sokolov participated from September 1990 through June 1992. The panelists recorded daily symptoms, medication intake, and peak expiratory flow (PEF). Statistical analysis was based on linear regression of population-averaged time series controlling for trend, meteorology, and autocorrelation. A temporospatial time series approach was also applied to the data to eliminate possible confounding by some known or unknown variables that occurred simultaneously in two of the study areas. Weak same-day effects and a stronger cumulative effect of air pollution on children was observed both for PEF and for symptoms. PEF decreased -0.90% (-1.35 to -0.46%), and a symptom score increased 14.7% (0.8-28.6%) in association with an average increase of 128 micrograms/m3 SO2 over the previous 5 days. Effects on adults were smaller and less consistent. Morbidity of children was best predicted by SO2 and sulfate concentrations. The authors conclude that prolonged, high exposure to winter-type pollution was associated with small adverse health effects in asthmatics.
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PMID:Acute health effects of exposure to high levels of air pollution in eastern Europe. 879 17

Recent epidemiologic studies have consistently reported increased daily mortality associated with exposures to particulate air pollution. Currently, particulate mass is measured as particles smaller than 10 microns (PM10). Fine (PM2.5) and coarse (PM10-PM2.5) mass and sulfate particle concentrations were measured in six eastern U.S. cities for eight years, and aerosol acidity concentrations were measured for approximately one year. Daily mortality for these metropolitan areas was combined with particulate air pollution and weather measurements. City-specific associations with each measure of particle pollution were estimated by Poisson regression, adjusting for time trends and weather by nonparametric methods. Combined effect estimates were calculated as the inverse variance weighted mean of the city-specific estimates. PM10, PM2.5, and SO4= were each significantly associated with increased daily mortality, while no associations were found with coarse mass nor with aerosol acidity (H+) concentrations. The strongest association was found with PM2.5. A 10 micrograms/m3 increase in two-day mean PM2.5 was associated with a 1.5% (95% CI 1.1% to 1.9%) increase in total daily mortality. Somewhat larger increases were found for deaths caused by chronic obstructive pulmonary disease (+3.3%) and by ischemic heart disease (+2.1%). These data suggest that increased daily mortality is specifically associated with particle mass constituents found in the aerodynamic diameter size range under 2.5 microns, that is, with combustion-related particles.
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PMID:Is daily mortality associated specifically with fine particles? 887 28

Naturally occurring fogs in industrialized cities are contaminated by acidic air pollutants. In Brussels, Belgium, the pH of polluted fogwater may be as low as 3 with osmolarity as low as 30 mOsm. In order to explore short-term respiratory effects of a realistic acid-polluted fog, we collected samples of acid fog in Brussels, Belgium, which is a densely populated and industrialized city, we defined characteristics of this fog and exposed asthmatic volunteers at rest through a face mask to fogs with physical and chemical characteristics similar to those of natural fogs assessed in this urban area. Fogwater was sampled using a screen collector where droplets are collected by inertial impaction and chemical content of fogwater was assessed by measurement of conductivity, pH, visible colorimetry, high pressure liquid chromatography, and atomic absorption spectrophotometry over a period of one year. The fogwater composition was dominated by NH4+ and SO4- ions. First we evaluated the possible effect of fog acidity alone. For this purpose 14 subjects with asthma were exposed at rest for 1 hr [mass median aerodynamic diameter to a large-particle (MMAD), 9 microns] aerosol with H2SO4 concentration of 500 micrograms/m3 (pH 2.5) and osmolarity of 300 mOsm. We did not observe significant change in pulmonary function or bronchial responsiveness to metacholine. In the second part of the work, 10 asthmatic subjects were exposed to acid fog (MMAD, 7 microns) containing sulfate and ammonium ions (major ions recovered in naturally occurring fogs) with pH 3.5 and osmolarity 30 mOsm. Again, pulmonary function and bronchial reactivity were not modified after inhalation of this fog. It was concluded that short-term exposure to acid fog reproducing acidity and hypoosmolarity of natural polluted fogs does not induce bronchoconstriction and does not change bronchial responsiveness in asthmatics.
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PMID:Acute exposure to realistic acid fog: effects on respiratory function and airway responsiveness in asthmatics. 897 17

As an approach to evaluating the public health burden from current air pollution levels, we examined the relationship of daily emergency room (ER) visits for respiratory illnesses (25 hospitals, average 98 visits/d) to air pollution in Montreal, Canada, from June through September, 1992 and 1993. Air pollutants measured included ozone (O3), particulate matter diameter < 10 microm (PM10) and < 2.5 microm (PM2.5), the sulfate fraction of PM2.5 (SO4), and aerosol strong acidity (H+). Temporal trends, autocorrelation, and weather were controlled for in time-series regressions. For 1992, no significant associations with ER visits were found. However, 33% of the particulate data were missing. For 1993, 1-h maximum O3, PM10, PM2.5, and SO4 were all positively associated with respiratory visits for patients over 64 yr of age (p < 0.02). An increase to the mean level of 1-h maximum O3 (36 ppb) was associated with a 21% increase over the mean number of daily ER visits (95% confidence interval [CI]: 8 to 34%). Effects of particulates were smaller, with mean increases of 16% (4 to 28%), 12% (2 to 21%) and 6% (1 to 12%) for PM10, PM2.5, and SO4, respectively. Relative mass effects were PM2.5 > PM10 >> SO4. Ozone and PM10 levels never exceeded 67 ppb and 51 microg/m3, respectively (well below the U.S. National Ambient Air Quality Standards of 120 ppb and 150 microg/m3, respectively). The present findings have public health implications with regard to the adverse health effects of urban photochemical air pollution on older individuals.
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PMID:Effects of air pollution on emergency room visits for respiratory illnesses in Montreal, Quebec. 903 96

The synthesis of goethite by oxidation of Fe2+ in presence of metallic iron was undertaken in an aqueous medium containing indifferent salts such as Na2 SO4 , (NH4 )2 SO4 , NaCl, and NH4 Cl. Temperature and bubbling air rate were maintained, respectively, at 70°C and 1 L/min. The influence of anions and cations on the kinetics of each step of the process has been followed distinctly, the iron dissolution rate has been determined by the variation of the medium acidity, and the precipitation of goethite has been determined by gravimetric measurements. With respect to Cl- , the SO4 2- anion decreases the rate of the two reactions. NH4 + acts as an inhibitor when it is present at low concentrations and as an accelerator for higher concentrations; the limit corresponding to the change of NH4 + behavior depends on the nature of the counter ion. The reaction product is composed of pure goethite in the presence of sulfate salts, whereas a mixture of goethite and lepidocrocite, respectively, 60-70 and 40-30%, was observed in the presence of chloride salts.
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PMID:Kinetics of the Formation of Goethite in the Presence of Sulfates and Chlorides of Monovalent Cations 924 Nov 66

In order to address the role that the ambient air pollution mix, comprised of gaseous pollutants and various physical and chemical measures of particulate matter, plays in exacerbating cardiorespiratory disease, daily measures of fine and coarse particulate mass, aerosol chemistry (sulfates and acidity), and gaseous pollution (ozone, nitrogen dioxide, sulfur dioxide, and carbon monoxide) were collected in Toronto, Ontario, Canada, in the summers of 1992, 1993, and 1994. These time series were then compared with concurrent data on the number of daily admissions to hospitals for either cardiac diseases (ischemic heart disease, heart failure, and dysthymias) or respiratory diseases (tracheobronchitis, chronic obstructive long disease, asthma, and pneumonia). After adjusting the admission time series for long-term temporal trends, seasonal variations, the effects of short-term epidemics, day of the week effects, and ambient temperature and dew point temperature, positive associations were observed for all ambient air pollutants for both respiratory and cardiac diseases. Ozone was least sensitive to adjustment for the gaseous and particulate pollution measures. However, the association between the health outcomes and carbon monoxide, fine and coarse mass, sulfate levels and aerosol acidity could be explained by adjustment for exposure to gaseous pollutants. Increases in ozone, nitrogen dioxide, and sulfur dioxide equivalent to their interquartile ranges corresponded to an 11% and 13% increase in daily hospitalizations for respiratory and cardiac diseases, respectively. The inclusion of any one of the particulate air pollutants in multiple regression models did not increase these percentages. Particle mass and chemistry could not be identified as an independent risk factor for the exacerbation of cardiorespiratory diseases in this study beyond that attributable to climate and gaseous air pollution. We recommend that effects of particulate matter on health be assessed in conjunction with temporally covarying gaseous air pollutants.
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PMID:The role of particulate size and chemistry in the association between summertime ambient air pollution and hospitalization for cardiorespiratory diseases. 928 96

Anionic carrier poly(N-vinylpyrrolidone-co-maleic acid) and its conjugates, prepared with coupling of 2-cyano-3-hydroxy-5-amino-2-pentenoyc(4-trifluoromethyl anilide) or (6', 7'-dimethyl-l'-quinoxalinyl)-4-(2' amino) acetanilide to the carrier, were analyzed by capillary zone electrophoresis (CZE) and micellar electrokinetic chromatography (MEKC) in the following buffers: 0.25 N triethylammonium phosphate (TEAP); sodium dodecyl sulfate (SDS; 25-150 mM) in TEAP (pH 2.25-6.30); 0.1 N Na-borate buffer (pH range 7-11) and SDS (25-150 mM) in Na-borate buffer (pH range 7-11). The presence of strong carboxyl groups (dissociated even at pH 2.25) on the polymer chain was proved by the CZE method. It was also proved by potentiometric titration that carboxyls with a wide range of acidity were on the polymer chain. CZE was able to differentiate among the analytes possessing carboxyl groups of different acidic strengths at pH 2.25. These components were not distinguished by CZE at high pH values (11.0). Interaction between the analyte and SDS affected the separation at this pH, and hence good resolution was obtained by MEKC. Informative separations were achieved both for the carrier and the conjugates in TEAP buffer at pH 2.25 by the CZE method. Optimal separation was achieved in borate buffer containing 75 mM SDS at pH 11.0 for the carrier and at pH 7.7 for the conjugates in MEKC.
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PMID:Analysis of polyanionic macromolecular carrier poly-(N-vinylpyrrolidone-co-maleic acid) and its bioconjugats by capillary electrophoresis. 954 94

Phospholipase A2 (PLA2) was purified about 180,000 times compared with the starting soluble-protein extract from developing elm (Ulmus glabra) seeds. On sodium dodecyl sulfate-polyacrylamide gel electrophoresis the purified fraction showed a single protein band with a mobility that corresponded to 15 kD, from which activity could be recovered. When analyzed by matrix-assisted laser-desorption ionization-time-of-flight mass spectrometry, the enzyme had a deduced mass of 13,900 D. A 53-amino acid-long N-terminal sequence was determined and aligned with other sequences, giving 62% identity to the deduced amino acid sequence of some rice (Oryza sativa) expressed sequence tag clones. The purified enzyme had an alkaline pH optimum and required Ca2+ for activity. It was unusually stable with regard to heat, acidity, and organic solvents but was sensitive to disulfide bond-reducing agents. The enzyme is a true PLA2, neither hydrolyzing the sn-1 position of phosphatidylcholine nor having any activity toward lysophosphatidylcholine or diacylglycerol. The biochemical data and amino acid sequence alignments indicate that the enzyme is related to the well-characterized family of animal secretory PLA2s and, to our knowledge, is the first plant enzyme of this type to be described.
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PMID:Purification and characterization of a low-molecular-weight phospholipase A2 from developing seeds of elm. 957 89

The effect of sodium dodecyl sulfate (SDS) micelles on the spectrofluorimetric intensities and on the solubility of two beta-blockers (atenolol and nadolol) were studied at 25.0 +/- 0.1 degrees C and I = 0.1 M NaCl. From the dependence of these physical properties on SDS concentration it was possible to calculate the binding constants drug-micelle, and it was found that both techniques yield similar results for the binding constants, and that are in agreement with those calculated from the effect of micelles on the apparent acidity constants of the beta-blockers.
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PMID:Fluorimetric and solubility studies of nadolol and atenolol in SDS micelles. 991 57

Twenty-four-hour samples of PM10 (mass of particles with aerodynamic diameter < or = 10 microm), PM2.5, (mass of particles with aerodynamic diameter < or = 2.5 microm), particle strong acidity (H+), sulfate (SO42-), nitrate (NO3-), ammonia (NH3), nitrous acid (HONO), and sulfur dioxide were collected inside and outside of 281 homes during winter and summer periods. Measurements were also conducted during summer periods at a regional site. A total of 58 homes of nonsmokers were sampled during the summer periods and 223 homes were sampled during the winter periods. Seventy-four of the homes sampled during the winter reported the use of a kerosene heater. All homes sampled in the summer were located in southwest Virginia. All but 20 homes sampled in the winter were also located in southwest Virginia; the remainder of the homes were located in Connecticut. For homes without tobacco combustion, the regional air monitoring site (Vinton, VA) appeared to provide a reasonable estimate of concentrations of PM2.5 and SO42- during summer months outside and inside homes within the region, even when a substantial number of the homes used air conditioning. Average indoor/outdoor ratios for PM2.5 and SO42- during the summer period were 1.03 +/- 0.71 and 0.74 +/- 0.53, respectively. The indoor/outdoor mean ratio for sulfate suggests that on average approximately 75% of the fine aerosol indoors during the summer is associated with outdoor sources. Kerosene heater use during the winter months, in the absence of tobacco combustion, results in substantial increases in indoor concentrations of PM2.5, SO42-, and possibly H+, as compared to homes without kerosene heaters. During their use, we estimated that kerosene heaters added, on average, approximately 40 microg/m3 of PM2.5 and 15 microg/m3 of SO42- to background residential levels of 18 and 2 microg/m3, respectively. Results from using sulfuric acid-doped Teflon (E.I. Du Pont de Nemours & Co., Wilmington, DE) filters in homes with kerosene heaters suggest that acid particle concentrations may be substantially higher than those measured because of acid neutralization by ammonia. During the summer and winter periods indoor concentrations of ammonia are an order of magnitude higher indoors than outdoors and appear to result in lower indoor acid particle concentrations. Nitrous acid levels are higher indoors than outdoors during both winter and summer and are substantially higher in homes with unvented combustion sources.
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PMID:Indoor, outdoor, and regional summer and winter concentrations of PM10, PM2.5, SO4(2)-, H+, NH4+, NO3-, NH3, and nitrous acid in homes with and without kerosene space heaters. 1006 53

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