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Results for “environmental sensitivity”

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At least 145 records · Page 8Linked to original sources
PubMed2002

Psychological reactions related to chemosensory irritation.

OBJECTIVES: For risk assessments of solvents the knowledge on chemosensory irritation effects is important, but the methodological base for that is incomplete. The psychological approach measuring chemosensory irritations leans on perceived symptoms and self-reported changes of well being. Characteristics assessing the validity of such psychological approaches are presented. METHODS: The article is based on 14 experimental inhalation studies with (mostly) 4-h exposures to acetone, 2-butanone, ethanol, ethyl acetate, ethyl benzene, iso-propanol, 1-octanol, and styrene. The profiles of exposure include constant and changing concentrations using the range of the German maximum concentrations at the workplace (MAK) list. Irritations (eyes and nose), olfactory symptoms (odour), and annoyance are the dependent variables measured by ratings. Young and healthy subjects ( n=160), - partially, subjects with self-reported odour sensitivity (measured by items from the questionnaire on chemical and general environmental sensitivity) - were investigated. RESULTS: The reliability of ratings is sufficient. Dose-response relationships for perceived odour and annoyance are stronger than those for irritations. A ranked order of the size of effect (related to the values before exposure) for the substances investigated shows correspondence between odour and annoyance; that for irritation differs. Within the limits of the MAK list, perceived irritations are not correlated to annoyance, whereas perceived bad smell correlates significantly to annoyance. Reversibility of the self-reported effects to approximately the pre-exposure level can be shown 1 h after cessation of the experimental exposure for the "normal" subjects. Influences of trait anxiety and chemical sensitivity on reports of annoyance, bad odour or irritation are only weak. CONCLUSION: The psychological approach of repeated measurements for self-reported irritation includes distinctive advantages compared with other methods, the simple and repeated availability during exposure, the sufficient reliability and dose-response relationship, and the comparability between substances by means of effect size. The extension of the concept of "chemosensory irritations" on reports for annoyance and bad smell can be recommended.

Air Pollutants, Occupational↗
PubMedDate not supplied

Fluorescence probe with a pH-sensitive trigger.

Acid-catalyzed hydrolysis was used as the mechanism to design a new type of environmentally sensitive fluorescence probe. A mild and selective periodate oxidation of the 2-amino alcohol of serine in the presence of a disulfide bond was developed to prepare dialdehyde peptides. Two identical fluorochrome hydrazide derivatives were then linked to the dialdehyde peptide forming an acid-labile hydrazone linkage. This self-quenched probe is weakly fluorescent at a physiological pH of 7.4 but shows more than 3-fold fluorescence enhancement at pH 4.5.

Amino Acid Sequence↗
PubMed2004

Evidence for genetic control of adult weight plasticity in the snail Helix aspersa.

Phenotypic plasticity and canalization are important topics in quantitative genetics and evolution. Both concepts are related to environmental sensitivity. The latter can be modeled using a model with genetically structured environmental variance. This work reports the results of a genetic analysis of adult weight in the snail Helix aspersa. Several models of heterogeneous variance are fitted using a Bayesian, MCMC approach. Exploratory analyses using posterior predictive model checking and model comparisons based on the deviance information criterion favor a model postulating a genetically structured heterogeneous environmental variance. Our analysis provides a strong indication of a positive genetic correlation between additive genetic values affecting the mean and those affecting environmental variation of adult body weight. The possibility of manipulating environmental variance by selection is illustrated numerically using estimates of parameters derived from the snail data set.

Animals↗
PubMed2005

Facile conversion of aptamers into sensors using a 2'-ribose-linked fluorophore.

In vitro selection can be used to identify nucleic acid receptors, called aptamers, that bind diverse small molecule targets. Aptamers therefore represent an attractive platform for creating sensors. Here, we report a straightforward, semi-rational approach for converting arbitrary aptamers into reagentless, single fluorophore biosensors. The local electrostatic environment at the 2'-ribose position is exquisitely sensitive to whether a nucleotide is conformationally restrained or not. Thus, by tethering an environmentally sensitive fluorescent group at an appropriate 2'-ribose group, we are able to generically detect ligand-induced conformational changes in aptamers. Three aptamers, including one for which no significant structural information can be inferred, were converted into robust small molecule sensors that function well in simple buffers, human urine, and bovine blood serum.

Biosensing Techniques↗
PubMed1998

Glutamate residues required for substrate binding and cleavage activity in mitochondrial processing peptidase.

Mitochondrial processing peptidase, a metalloendopeptidase consisting of alpha- and beta-subunits, specifically recognizes a large variety of mitochondrial precursor proteins and cleaves off N-terminal extension peptides. The enzyme requires the basic amino acid residues in the extension peptides for effective and specific cleavage. To elucidate the mechanism involved in the molecular recognition of substrate by the enzyme, several glutamates around the active site of the rat beta-subunit, which has a putative metal-binding motif, H56XXEH60, were mutated to alanines or aspartates, and effects on kinetic parameters, metal binding, and substrate binding of the enzyme were analyzed. None of mutant proteins analyzed was impaired in dimer formation with the alpha-subunit. Mutation of glutamates at positions 79, 129, and 136, in addition to an active-site glutamate at position 59, resulted in a marked decrease in cleavage efficiency. Together with sequence alignment data, glutamate 136 appears to be involved in metal binding. Glutamate 129 is mostly responsible for the catalysis, as there was a considerable decrease in kcat value by the mutation. Mutation of glutamate 79 led to decrease in kcat value and increase in Km values. Substrate binding experiments using an environmentally sensitive fluorescence probe attached to the peptide showed that the mutation caused a remarkable environmental change at the binding site to the N-terminal region of the substrate peptide and decreased binding of the peptide, thereby suggesting that glutamate 79 participates primarily in substrate binding. Thus, some glutamate residues required for substrate binding and cleavage activity have been identified.

Amino Acid Sequence↗
PubMed2004

MAX3/CCD7 is a carotenoid cleavage dioxygenase required for the synthesis of a novel plant signaling molecule.

BACKGROUND: Plant development is exquisitely environmentally sensitive, with plant hormones acting as long-range signals that integrate developmental, genetic, and environmental inputs to regulate development. A good example of this is in the control of shoot branching, where wide variation in plant form can be generated in a single genotype in response to environmental and developmental cues. RESULTS: Here we present evidence for a novel plant signaling molecule involved in the regulation of shoot branching. We show that the MAX3 gene of Arabidopsis is required for the production of a graft-transmissible, highly active branch inhibitor that is distinct from any of the previously characterized branch-inhibiting hormones. Consistent with its proposed function in the synthesis of a novel signaling molecule, we show that MAX3 encodes a plastidic dioxygenase that can cleave multiple carotenoids. CONCLUSIONS: We conclude that MAX3 is required for the synthesis of a novel carotenoid-derived long-range signal that regulates shoot branching.

Abscisic Acid↗
PubMed1999

The association of smoking with sensitization to common environmental allergens: results from the European Community Respiratory Health Survey.

BACKGROUND: Smoking is a risk factor for sensitization to some occupational allergens, but its association with sensitization to common environmental allergens remains unclear. OBJECTIVE: We sought to determine the association of smoking with total IgE levels and with sensitization to 3 common environmental allergens in data from the European Community Respiratory Health Survey. METHODS: A detailed smoking history and blood sample for determination of serum total IgE and specific IgE levels to house dust mite, grass, and cat allergens was obtained from 13,002 randomly selected young adults living in the areas served by 34 centers in 14 countries. Associations with smoking status and amount smoked were determined. Because there was evidence of heterogeneity between centers in the association of age, sex, and smoking with sensitization, odds ratios (ORs) were determined for each center and combined by using random-effects meta-analysis. RESULTS: Compared with lifetime nonsmokers, current smokers were at an increased risk of sensitization to house dust mite allergen (OR, 1.13; 95% confidence interval [CI], 1.02-1.26) but a decreased risk of sensitization to grass (OR, 0.76; 95% CI, 0.67-0.88) and cat allergens (OR, 0.69; 95% CI, 0.59-0.80). Exclusion of those with symptoms suggestive of current asthma strengthened the association of smoking with sensitization to house dust mite allergen (OR, 1.29; 95% CI, 1.11-1. 50). The geometric mean total IgE level was higher in smokers and was higher among those who currently smoked the most compared with those who smoked less than 5 cigarettes per day. CONCLUSION: The association between smoking and sensitization to common environmental allergens is different for different allergens.

Adult↗
PubMed1997

Testing the neural sensitization and kindling hypothesis for illness from low levels of environmental chemicals.

Sensitization in the neuroscience and pharmacology literatures is defined as progressive increase in the size of a response over repeated presentations of a stimulus. Types of sensitization include stimulant drug-induced time-dependent sensitization (TDS), an animal model related to substance abuse, and limbic kindling, an animal model for temporal lobe epilepsy. Neural sensitization (primarily nonconvulsive or subconvulsive) to the adverse properties of substances has been hypothesized to underlie the initiation and subsequent elicitation of heightened sensitivity to low levels of environmental chemicals. A corollary of the sensitization model is that individuals with illness from low-level chemicals are among the more sensitizable members of the population. The Working Group on Sensitization and Kindling identified two primary goals for a research approach to this problem: to perform controlled experiments to determine whether or not sensitization to low-level chemical exposures occurs in multiple chemical sensitivity (MCS) patients; and to use animal preparations for kindling and TDS as nonhomologous models for the initiation and elicitation of MCS.

Animals↗
PubMed1997

Metals of the bottom muds in Belize City Harbor, Belize.

Seven bottom samples extending from the ocean up through Belize Harbor and City were acid leached (EPA method 200.7) and analyzed using inductively coupled plasma spectrometry to measure the bioavailability of Cd, Cr, Cu, Pb and Zn. Soil and environmental chemists would compare data to world averages of unpolluted soils, these samples were higher than this average by a factor of 10 for Cd, 4 for Cu, 2.7 for Zn and 2.6 for Pb. Geochemists argue that it's hard to find unpolluted soil so their comparison is with world average of ancient (pre-man) shales and the Belize samples were higher than this shale average by a factor of 30 for Cd, 3.7 for Pb, 2.2 for Cu and 1.7 for Zn. Ecologists would argue that the metal effect on the biota is the correct way to analyze the data by using the biological effects toxicity method, and this way the samples were above the lower limit by a factor of 5.1 for Cd, 2.9 for Cu and 1.6 for Pb. By all three lines of reasoning, it can be concluded that Cd, Cu, Pb and Zn, in that order, pose environmental problems. Since this site is located in the middle of Belize Barrier Reef, a highly sensitive environmental area that is also economically important to Belize, it poses a critical problem that needs to be addressed further.

Journal Article↗
PubMed2004

Phenotypic selection and regulation of reproduction in different environments in wild barley.

Plasticity of the phenotypic architecture of wild barley, Hordeum spontaneum, was studied in response to water and nutrient stress. Direct and indirect selection on several vegetative and reproductive traits was estimated and path analysis used to reveal how regulating pathways via maternal investment differed between environments. Vegetative traits displayed differential regulating effect on fitness across experimental environments: (1) increase in size was selected for under optimal conditions and under water stress, but not under nutrient stress; (2) allocation to root biomass was selected for under optimal conditions, but it had no effect under nutrient stress and was strongly selected against when water was limiting; (3) delayed onset of reproduction was selected under nutrient limitation whereas earlier onset was selected under water stress. The regulating effect of reproductive traits on final reproductive output also differed across treatments, operating either at the 'early' stage of plant development through varying the number of initiated spikelets per spike (no stress and water stress treatment) or at the 'late' developmental stage adjusting the fertile spikelet weight (no stress and nutrient stress treatment). Reproductive output was regulated via seed abortion under no stress and water stress treatments. Although the underlying mechanism of the regulation through abortion has yet to be discovered, the specific mechanism of abortion under water stress appears to be different from that under optimal conditions. Our results demonstrate that not only is the character architecture in wild barley plastic and sensitive to changing availability of water and nutrients, but the regulating mechanism of maternal investment is also environmentally sensitive.

Analysis of Variance↗
PubMed1990

Stress, depression, and mania: relationship between perceived role of stressful events and clinical and biochemical characteristics.

We investigated the perceived role of stressful events in episodes of major affective disorder in patients studied in the NIMH Clinical Research Branch Collaborative Program on the Psychobiology of Depression (Biological Studies). Using items from the Schedule for Affective Disorders and Schizophrenia (SADS), episodes were divided into environment-sensitive (high perceived role of stressful events) and autonomous (minimal or no perceived role of stressful events). Patients with environment-sensitive episodes had fewer previous episodes and a longer index episode. The groups did not differ with respect to age, gender, education, socioeconomic group, diagnosis, severity of illness, or eventual response to treatment. Unipolar depressed patients with environment-sensitive episodes had lower CSF 5-HIAA than those with autonomous episodes. Among bipolar depressed patients, those with autonomous episodes had elevated excretion of O-methylated catecholamine metabolites and of epinephrine, while those with environment-sensitive episodes had normal excretion of catecholamines and metabolites. Manic subjects with environment-sensitive episodes had elevated norepinephrine excretion, while this was normal in manics with autonomous episodes. Relationships between environmental sensitivity of affective episodes and neurotransmitter function therefore appear to be related to the type of episode.

Adaptation, Psychological↗
PubMed1996

Fluorescence lifetime imaging: an emerging technique in fluorescence microscopy.

Fluorescence microscopy is an important tool for biological research, in part because of the extremely high detection sensitivity that can be achieved, but also because fluorescent molecules can be used as probes on account of their environmental responsiveness, for example to measure intracellular pH or metal ion concentration. Unfortunately, the environmental sensitivity can sometimes be a source of problems because of enhancement or 'quenching', which can make it very difficult to relate emission intensity to the amount of fluorophore present. The measured intensity is essentially proportional to the product of the amount of fluorophore present in the sample and the local quantum yield of the fluorophore (the quantum yield can be thought of as the probability that an excited molecule decays by fluorescence emission rather than by other non-radiative processes). This is a particular difficulty in an environment such as a cell or tissue slice in which quantum yield and flurophore concentration can both vary within the sample. Ideally we would wish to be able to measure the quantum yield of fluorescence as well as the fluorescence intensity, as this would allow environmental effects to be compensated for. Unfortunately, this is not at all easy, and indirect means to achieve the same goal are more appropriate. A recently introduced technique, fluorescence lifetime imaging (Morgan et al. 1992, Wang et al. 1992), offers one such means to improve quantification of fluorescence microscopy. In addition, as will be explained, the technique offers the prospect of significantly improving detection sensitivity in appropriate circumstances.

Energy Transfer↗
PubMed2002

Home and allergic characteristics of children with asthma in seven U.S. urban communities and design of an environmental intervention: the Inner-City Asthma Study.

Most published environmental remediation interventions have been directed at single allergens and have employed demanding strategies; few have been performed in the homes of inner-city children disproportionately burdened by asthma. Our objective was a) to describe the allergen sensitivities, environmental tobacco smoke (ETS) exposure, and home environmental characteristics of a national sample of inner-city children with moderate to severe asthma and b) to develop and implement a multifaceted, home-based comprehensive intervention to reduce home allergens and ETS, tailored to the specific sensitization and exposure profiles of those children. Allergen skin testing and a home evaluation were performed to determine the presence of ETS and factors known to be associated with increased indoor allergen levels. Based on published remediation techniques, a home environmental intervention, organized into modules, each addressing one of five specific allergen groups or ETS, was designed. Of 994 allergic children from seven U.S. urban communities, 937 successfully completed baseline interviews and home allergen surveys and were enrolled. More than 50% of children had positive skin tests to three or more allergen groups. Cockroaches were reported in 58% of homes, wall-to-wall carpeting in the child's bedroom in 55%, a smoker in 48%, mice or rats in 40%, and furry pets in 28%. More than 60% of enrolled families received four or more modules, and between 94% and 98% of all modules were completed. We conclude that most inner-city children with moderate to severe asthma are sensitized to multiple indoor allergens and that environmental factors known to be associated with asthma severity are commonly present in their homes. The intervention developed for the Inner-City Asthma Study employs accepted methods to address an array of allergens and ETS exposure while ensuring that the intervention is tailored to the specific sensitization profiles and home characteristics of these children.

Adult↗
PubMed2003

A feasibility study of a Salix viminalis gravel hydroponic system to renovate primary settled wastewater.

A Salix viminalis/gravel system based on hydroponics was developed for wastewater renovation in order to avoid the problems of soil damage and pollution associated with long-term application of wastewater to soil. For such a system to work the mineral elements applied must match closely the requirements of the tree species. To examine this the growth and nutrient uptake of S. viminalis in wastewater was compared with that in Long Ashton nutrient solution (1/4 strength). S. viminalis grew more slowly in wastewater than in Long Ashton solution, but exhibited no obvious deficiency or toxicity symptoms. Since industrial wastewaters often contain metals, the extent to which copper might inhibit wastewater treatment in this system was also examined. S. viminalis was grown in wastewater amended with 10 and 100 ppm copper. Trees were unaffected by wastewater with 10 ppm copper when compared to trees grown in wastewater alone. Wastewater containing with 100 ppm copper was too toxic for the trees to thrive and wastewater treatment was reduced. Treatment efficiencies for unamended wastewater were 57.7% for nitrogen, 90.6% for phosphorus and 24.9% for potassium. These efficiencies are much greater than those quoted for a Salix/soil system, and thus Salix/gravel systems may have potential for wastewater treatment in environmentally sensitive areas or situations.

Biodegradation, Environmental↗
PubMed1993

Assessment of the effects of atmospheric oil pollution in post war Kuwait.

A prospective study was undertaken to assess and monitor the effects of oil pollution in soldiers exposed in Kuwait in 1991 after Op Granby. One hundred and twenty five soldiers were monitored over a five month period by measurement of Forced Expiratory Volume (in one second) (FEV1) and Forced Vital Capacity (FVC). Although no demonstrable changes were observed, this study has gone some way to filling the gap in research in this environmentally sensitive field.

Air Pollution↗
PubMed1977

Use of a distant reporter group as evidence for a conformational change in a sensory receptor.

A highly sensitive method for demonstrating ligand-induced conformational changes in protein molecules in solution is described. The method utilizes an environmentally sensitive reporter group that is known to be distant from the active site. In the present application a conformational change is demonstrated in the galactose receptor of Salmonella typhimurium, involved in bacterial sensing and transport, by means of an extrinsic fluorophore, 5-iodoacetamidofluorescein, attached at a single methionine residue, and the intrinsic tryptophan fluorophore. Binding of the ligand galactose perturbs the microenvironment of both the fluorescein and tryptophan, as shown by both spectral and potassium iodide quenching changes. The distance between the two dyes is established by fluorescence energy transfer methods to be 41 +/- 10A. Since only one molecule of galactose binds per molecule of receptor and since the galactose molecule is only about 5 A in length, changes at one of these sites reflect the result of an indirect effect. Hence, there must be a ligand-induced conformational change that is propagated a minimum of 30 A through the receptor molecule.

Bacterial Proteins↗
PubMed1977

Fate of arsenicals in different environmental substrates.

The current knowledge of arsenic (As) transformations in the environment, as well as some gaps in this knowledge, are reviewed. These transformations involve As chemical and biochemical transformations in air, waters, sediments, and soils. Arsenic moves in a dispersive manner through air and water and is in physical and chemical equilibrium in many substrates. It is oxidized, reduced, methylated, volatilized, incorporated into biotic tissues, excreted, adsorbed, and desorbed. Oceanic sediments become the eventual sink for As. The rates of As movement and transformation vary with environmental conditions. Besides inorganic As, various methylated arsenicals are found naturally at environmentally sensitive equilibrium concentrations, which are probably maintained biotically. An As-transformation model has been constructed from rate constants derived from field observations. The environmental factors affecting these rate constants are discussed.

Air Pollutants↗
PubMed2001

Golf course development in a major tourist destination: implications for planning and management.

The planning and design of golf course developments is influenced by many factors. This paper focuses on the environmental ramifications of insufficient or lack of compliance with standard environmental and economic planning practices. Specifically, it looks at a tourist destination location that was under the influence of extensive land development and investment speculation. The Gold Coast in Australia was the focal point for large overseas investment due to changes in government legislation regarding foreign investment. Due to the economic climate in the second half of the 1980s many golf course resort developments were built, approved, or planned. Many of these circumvented normal business and environment planning processes. The result has been a dangerous concentration of golf facilities in environmentally sensitive areas and an oversupply of golf facilities. Both of these matters are discussed in terms of the general planning process and the potential economic and environmental impacts to the Gold Coast and similar destinations in other parts of the world.

Commerce↗