Biological activity of J-2931 against mosquitoes (Diptera: Culicidae) and selected nontarget organisms and assessments of potential environmental impact.
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Animals↗
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Results for “Environmental selection”
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Dioxins and dibenzofurans in adipose tissue of the general US population and selected subpopulations.
OBJECTIVES: The Environmental Protection Agency's National Human Adipose Tissue Survey (NHATS) was conducted in fiscal year (FY) 1987 to (1) estimate average concentrations of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in the adipose tissue of humans in the US population, (2) identify differences in average concentrations among subpopulations, and (3) compare average concentrations with those from the FY 1982 NHATS: METHODS: Population estimates of the average levels of PCDDs and PCDFs were established on the basis of 865 human adipose tissue specimens collected in FY 1987. Average levels among subpopulations were compared. RESULTS: The average concentration of 2,3,7,8-tetrachlorodibenzo-p-dioxin in the adipose tissue of the US population was 5.38 pg/g, increasing from 1.98 pg/g in children under 14 years of age to 9.40 pg/g in adults over 45. The effect of age was significant for nine compounds. Regional differences in the levels of 2,3,4,7,8-pentachlorinated dibenzofurans were statistically significant, but there were no significant differences associated with sex or race. CONCLUSIONS: The survey provides a baseline of average levels of PCDDs and PCDFs in the adipose tissue of humans in the US population.
Adipose Tissue↗
Aquatic toxicity of selected chemicals as a basic criterion for environmental classification.
In order to protect public health and the environment, the EU legislation has proposed a classification of dangerous substances. Chemicals are classified according to physico-chemical as well as toxicological and ecotoxicological properties. Environmental classification is based on inherent harmful potential of a substance to organisms and on its environmental fate, that is, degradation and bioaccumulation potential. In this study, experimental data on acute and chronic toxicity to aquatic organisms and biodegradability and bioaccumulation data obtained from literature were used to classify arsenic (applied as As2O3), copper (applied as CuCl2), phenol and 1,4-butynediol. For this purpose, the "base set data" obtained from standardised test methods served as a convenient indicator of the inherent toxicity of tested chemicals. Additional data about environmentally relevant properties of arsenic and 1,4-butynediol could lead to a revision of present chemical classification and labelling.
Animals↗
[Selected biochemical indicators of the effect of environmental lead on the humans].
Lead after penetration into the human organism reacts with different sulphur compounds, especially with thiol group of peptides and proteins. It diminishes haeme synthesis by inhibiting thiol enzymes of bone marrow. Measurements performed in three groups of inhabitants of Chorzów--the most polluted town in the Upper Silesia, revealed in approx. 70% of workers of Nitrogen Chemical Plant (group A) and Steelworks (group S) a several-fold higher concentrations of blood lead, than in workers of Slaughterhouse (group M) in which it remained within the normal range for urban populations. In all subjects examined, the level of reduced glutathione in erythrocytes was approx. 50% lower in comparison to normal mean value. In urine, the highest excretion of delta-aminolevulinic acid (ALA), a precursor for haeme synthesis was found in group A, characterized by highest blood lead as well as in group M, with normal blood lead concentrations. The ALA excretion in group S was lower but it also exceeded the upper limit of normal range. Amounts of porphobilinogen excreted in urine exceeded the normal range, more frequently in group A and M than in group S, as in the case of ALA. These results indicate a widespread exposition of Chorzów inhabitants to lead, although the altered amounts of compounds studied show no correlation with the lead concentrations in blood. It seems that blood lead concentration may be modified depending on individual metabolic features, work conditions or diet.
Abattoirs↗
[Selection and use of microorganisms for metabolizing environmental chemicals with chlorinated aromatics as an example].
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Bacteria↗
[Temporal and spatial analysis of hospitalization for selected diseases in Poland due to certain environmental factors. II. Spatial analysis of environmental differences].
The present study was aimed at assessment of a degree of regional differences in hospitalized morbidity in Poland for some of diseases considered to be related to environmental contamination and its relationship with general environmental characteristic of the regions. The performed analysis has shown that however in recent years there have been substantial differences in the discharge rates between provinces of Poland, these differences are not well explained by differences in general environmental factors. The possible reasons of these results have been discussed.
Congenital Abnormalities↗
A general model to account for enzyme variation in natural populations.
Approximate conditions for genetic polymorphism in temporally and spatially varying environments are presented for loci which are intermediate at the level of fitness or at the level of gene function. The conditions suggest that polymorphism will be more likely in more variable environments while unlikely in constant environments. Biochemical evidence is presented to justify the assumption of heterozygote intermediacy. Observations on natural populations are cited which substantiate the claim that allozymic polymorphism is primarily due to selection acting on environmental variation in gene function.
Animals↗
Application of a macrocycle immobilized silica gel sorbent to flow injection on-line microcolumn preconcentration and separation coupled with flame atomic absorption spectrometry for interference-free determination of trace lead in biological and environmental samples.
A simple and highly selective flow injection on-line pre-concentration and separation-flame atomic absorption spectrometric method was developed for routine analysis of trace amounts of lead in biological and environmental samples. The selective preconcentration of lead was achieved in a wide range of sample acidity (0.075 to > or = 3 mol L(-1)HNO3) on a microcolumn (145 microL) packed with a macrocycle immobilized on silica gel. The lead retained on the column was effectively eluted with an EDTA solution (0.03 mol L(-1), pH 10.5). Three kinds of potential interferences, i.e., preconcentration inferences from metal ions with an ionic radius similar to that of Pb(II) due to their competition for the cavity of the macrocyle, elution kinetic interferences from ions which form stable complexes with EDTA due to their competition for EDTA, and interferences in the atomizer from residual matrix, were evaluated and compared in view of the read-out mode of the analyte response (peak area vs peak height), column wash step (with vs without), column capacity (50 vs 145 microL), and column shape (conical vs cylindrical). The results showed that a combination of increase in column capacity, quantitation based on peak area, and use of dilute nitric acid for column wash before elution efficiently avoid the above-mentioned potential interferences. With the use of a 145 microL column the present system tolerated up to 0.1 g L(-1) Ba(II), 1 g L(-1) Sr(II), and at least 10 g L(-1) Fe(III), Cu(II), Ni(II), Zn(II), Cd(II), Al(III), K(I), Na(I), CaII), and Mg(II) in the sample digest. Further improvement of the interference tolerance can be achieved by increasing column capacity if more complicated samples need to be analyzed. At a sample loading rate of 3.9 mL min(-1) with 30-s preconcentration, an enrichment factor of 52, a detection limit (3s) of 5 micrograms L(-1) Pb in the digest and a sampling frequency of 63 h(-1) were obtained. The precision (RSD, n = 11) at the 200 micrograms L(-1) level was 1.9%. The enrichment factor and the detection limit can be further improved by increasing sample loading rate without degradation in the efficiency due to the favorable kinetics and low hydrodynamic impedance of the present system. The analytical results obtained by the proposed method for a number of biological and environmental standard reference materials were in good agreement with the certified and recommended values.
Animals↗
Self-reproducing system can behave as Maxwell's demon: theoretical illustration under prebiotic conditions.
The recent discovery of polymerase activity in a ribosomal RNA intervening sequence as well as other studies of RNA-replicating systems suggest that the first living molecules were RNAs called replicases. According to this suggestion from biochemical studies, the replicase system is chosen as the simplest case of self-reproducing systems, and the fundamental problem of "what is life" is theoretically investigated by analysing the behavior of a replicase system with a supply of organic materials under prebiotic conditions. In this analysis, it is essential to consider (i) self-reproduction on the basis of its own information, (ii) maintenance and improvement of the information by selection and (iii) environmental event of non-biologically generating organic materials from inorganic matter by photochemical reactions, probably occurring in prebiotic conditions on the Earth. The replicases can retain and further elevate their self-reproducibility through competition among their descendant mutants for acquiring a limited quantity of materials, if the initial ability of self-reproduction and the concentration of replicases are above some critical values. By this selection, the replicase molecules retain a narrowed range of nucleotide sequences, or a state of lower entropy, against the natural tendency of sequence divergence, but this entropy reduction is sufficiently compensated by the entropy production in the environmental event of energy conversion from photons to heat. Once the stability of a self-reproducing system is established in the above sense, the self-reproducing system can operate as Maxwell's demon to regulate the outside flow of matter by its catalytic function without any contradiction to the second law of thermodynamics.
Animals↗
Environmental control of tuberculosis: continuing controversy.
The incidence of tuberculosis--and, more important, that of multidrug-resistant tuberculosis--have risen drastically in the past decade. Nosocomial outbreaks have alerted health-care workers to the hazards of the spread of tuberculosis. The use of environmental control modalities (e.g., ventilation, air filtration, and ultraviolet irradiation) and personal protective devices has been explored in the medical, legislative, and public forums. New regulations and legislation have created controversy over the recommendations and their interpretation. In this review we present the theory behind the rational selection of environmental-control modalities and personal protective devices. We also offer suggestions about the application of specific control techniques and the revision of existing facilities to comply with new standards.
Air Microbiology↗
Porcine IgA allotypes are not equally transcribed or expressed in heterozygous swine.
The prediction of 1:1 expression of constant region allotypes in heterozygous animals assumes that productive VDJ rearrangements occur at random between chromosomes, switch recombination is random, there is no allele-related defect in switching and there is no selection for a B-cell receptor bearing a certain constant region allotype. In data reported here, this prediction was often not fulfilled for the transcripts encoding the IgAa and IgAb alleles of porcine IgA including those from late term fetal piglets that are not in contact with environmental antigens or maternal regulatory factors. In the spleen, thymus, mesenteric lymph node (MLN), ileal Peyer patches, parotid gland and PBLs of 5-week-old conventionally-reared Duroc pigs, ratios of IgAa to IgAb transcripts as high as 4:1 were observed. Since White Cross animals had significantly higher levels of IgAb than IgAa (some >3-fold), a allele-linked switch defect cannot explain the deviation from the expected 1:1 ratio. When the IgAa:IgAb ratios in older Durocs and those reared at a different site were studied, no evidence for breed dependence of differential transcription was found. Total serum IgA levels paralleled total transcript levels in PBLs while particularly in White Cross animals, the IgAa:IgAb ratio in serum was higher in many animals than the IgAa:IgAb transcript ratio in their PBLs. We conclude that deviations from the expected 1:1 ratio of allotype transcripts and secreted IgA in young pigs is normal and deviations from this ratio also occur during fetal life in the absence of environmental antigens and maternal regulatory factors. We speculate that postnatal deviations result from: (A) exposure to environmental antigens that selectively expand B-cells expressing V(H) gene alleles linked to either IgAa or IgAb or (B) some form of colostrum-dependent regulation. Pre-natal regulation may depend on the selection of B-cells bearing certain V(H) or C(H) encoded BCRs by stromal ligands such as fetal B-cell superantigens.
Animals↗
Spousal similarity in subjective well-being: the Cardiovascular Health Study.
This study examines the extent to which one spouse's subjective well-being predicts that of the partner (N = 1,040 spousal pairs, 65 years or older). Prior research is extended in two ways: (a) The similarity of both affective domains (depressive symptoms, feelings about life as a whole, and satisfaction with the meaning and purpose of life) and nonaffective domains (perceived health) are examined, and (b) known predictors of well-being in older adults (sociodemographic variables, self and spouse health status variables, and exposure to common environmental events) are statistically controlled. Results indicate that one spouse's assessments of well-being and depression predict the other's well-being even after controlling for known predictors of these outcomes. Given the similarity of findings for affective and nonaffective domains, multiple mechanisms, including contagion, mate selection, and common environmental influences, are speculated as likely to contribute to this phenomenon.
Activities of Daily Living↗
Thermoregulatory consequences of long-term microwave exposure at controlled ambient temperatures.
This study was designed to identify and measure changes in thermoregulatory responses, both behavioral and physiological, that may occur when squirrel monkeys are exposed to 2450-MHz continuous wave microwaves 40 hr/week for 15 weeks. Power densities of 1 or 5 mW/cm2 (specific absorption rate = 0.16 W/kg per mW/cm2) were presented at controlled environmental temperatures of 25, 30, or 35 degrees C. Standardized tests, conducted periodically, before, during, and after treatment, assessed changes in thermoregulatory responses. Dependent variables that were measured included body mass, certain blood properties, metabolic heat production, sweating, skin temperatures, deep body temperature, and behavioral responses by which the monkeys selected a preferred environmental temperature. Results showed no reliable alteration of metabolic rate, internal body temperature, blood indices, or thermoregulatory behavior by microwave exposure, although the ambient temperature prevailing during chronic exposure could exert an effect. An increase in sweating rate occurred in the 35 degrees C environment, but sweating was not reliably enhanced by microwave exposure. Skin temperature, reflecting vasomotor state, was reliably influenced by both ambient temperature and microwaves. The most robust consequence of microwave exposure was a reduction in body mass, which appeared to be a function of microwave power density.
Animals↗
Effect of growth rate and cultivation environments on cloned gene stability and the cloned gene product formation in Streptomyces lividans.
The growth rate and environmental effects on the stability of recombinant plasmid, pDML6 containing beta-lactamase gene, and the cloned gene product formation in Streptomyces lividans were studied. A maximum production rate of the cloned gene product was obtained at a specific growth rate 0.106 h-1 in glucose-limited chemostat cultivations without genetic selection pressure. Optimum environmental conditions for the recombinant plasmid stability and maximum formation rates of the cloned gene product were determined using continuous cultivations at the optimum specific growth rate. The fractions of plasmid harboring mycelium in prolonged cultivation up to 50 generations were varied from 77 to 95%. The recombinant plasmid was stably maintained in the host cells grown in different temperatures (24 to 36 degrees C) and pH (6.0 to 8.5). The formation of the cloned gene product was optimum at pH 7.0 and 27 degrees C, at which the maximum enzyme production rate was 0.82 kU g-1 h-1. Continuous cultivations varying the dissolved oxygen tension (10 to 80% air saturation) showed that the plasmids were maintained stably and the specific enzyme production rates were increased with increasing dissolved oxygen levels.
Hydrogen-Ion Concentration↗
Adherence to HEp-2 cells and enteropathogenic potential of Aeromonas spp.
Aeromonas strains (total = 60) of clinical, water and food origin were tested for adherence to HEp-2 cells. Environmental strains were selected (except for A. caviae) to include primarily those expressing other virulence-associated properties. Adhesion was markedly species-dependent (A. veronii biotype sobria, 15 of 26 [58%]. A caviae, 4 of 12 [33%] and A. hydrophila, 2 of 8 [11%]). A. veronii biotype sobria were adhesive, irrespective of source (62 and 54% for clinical and environmental strains, respectively). Adherent strains of this species were enterotoxin-positive and most (13 of 15) grew at 43 degrees C. A. caviae isolated from clinical specimens contained a higher proportion (75%) of adherent strains than environmental strains (13%). Virulent subsets of A. veronii biotype sobria and A. caviae are adherent to HEp-2 cells. The HEp-2 assay is a useful model for investigating mechanisms of adherence and enteropathogenicity of virulent Aeromonas species.
Aeromonas↗
Comparing strengths of directional selection: how strong is strong?
The fundamental equation in evolutionary quantitative genetics, the Lande equation, describes the response to directional selection as a product of the additive genetic variance and the selection gradient of trait value on relative fitness. Comparisons of both genetic variances and selection gradients across traits or populations require standardization, as both are scale dependent. The Lande equation can be standardized in two ways. Standardizing by the variance of the selected trait yields the response in units of standard deviation as the product of the heritability and the variance-standardized selection gradient. This standardization conflates selection and variation because the phenotypic variance is a function of the genetic variance. Alternatively, one can standardize the Lande equation using the trait mean, yielding the proportional response to selection as the product of the squared coefficient of additive genetic variance and the mean-standardized selection gradient. Mean-standardized selection gradients are particularly useful for summarizing the strength of selection because the mean-standardized gradient for fitness itself is one, a convenient benchmark for strong selection. We review published estimates of directional selection in natural populations using mean-standardized selection gradients. Only 38 published studies provided all the necessary information for calculation of mean-standardized gradients. The median absolute value of multivariate mean-standardized gradients shows that selection is on average 54% as strong as selection on fitness. Correcting for the upward bias introduced by taking absolute values lowers the median to 31%, still very strong selection. Such large estimates clearly cannot be representative of selection on all traits. Some possible sources of overestimation of the strength of selection include confounding environmental and genotypic effects on fitness, the use of fitness components as proxies for fitness, and biases in publication or choice of traits to study.
Models, Genetic↗
Escherichia coli O157:H7 outbreak associated with consumption of ground beef, June-July 2002.
OBJECTIVE: A case-control and environmental study tested the hypothesis that purchasing and eating ground beef from a specific source was the cause of a cluster of cases of hemolytic uremic syndrome (HUS) and Escherichia coli (E. coli) O157:H7 gastroenteritis. METHODS: A case-control study comparing risk factors was conducted over the telephone on nine case-patients with 23 selected controls. An environmental investigation was conducted that consisted of reviewing beef handling practices at a specific local supermarket and obtaining ground beef samples from the store and two households with case-patients. RESULTS: The analysis of the case-control study showed that eight case-patients (89%) purchased ground beef at Grocery Chain A compared with four controls who did not develop illness (17%) (matched odds ratio=undefined; 95% confidence interval 2.8, infinity; p=0.006). The environmental investigation showed that Grocery Chain A received meat from Meatpacker A. Laboratory analysis of meat samples from Meatpacker A and Grocery Chain A and stool samples from some patients recovered an identical strain of E. coli O157:H7 according to pulse-field gel electrophoresis. CONCLUSIONS: Both the case-control and environmental studies showed that purchasing ground beef at Grocery Chain A, which received ground beef from Meatpacker A, was the major risk factor for illness in eight case-patients; the ninth case-patient was found to be unrelated to the outbreak. Furthermore, meat from Meatpacker A was associated with a nationwide outbreak of E. coli O157:H7 illness that resulted in the second largest recall of beef in U.S. history at the time.
Adolescent↗
[Understanding of environmental impact with inpatients based on structural modeling].
This study examined how inpatients perceive environmental impacts using the ISM(Interpretive Structural Modeling)method. 18 new items among inpatients perceiving the environmental impacts were selected through a discussion with three researchers, two nurses, and six patients. This was applied to two inpatients who were not in the same ambulatory state in order to establish the validity of the structural models. As a result, the structuring models showed the difference depending on each patient. Therefore the structuring model is effective to assess the environmental impacts on individuals.
Humans↗