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At least 163 records · Page 9Linked to original sources
PubMed1983

The structuring of an allergy index based on IgE-mediated skin sensitivity to common environmental allergens.

We computed skin-test sensitivity levels in 485 adults puncture-tested with eight standardized, high-quality inhalant allergens tested at single concentrations. In order to quantitate the "average" IgE-mediated skin sensitivity of each subject, we used both nonparametric and parametric statistical methods to generate two "allergy indices" (Allergy Index I and Allergy Index II) based on sensitivity end-point data from the subpopulations of individuals positive to six of the eight allergens. For the 192 skin test-positive subjects, Allergy Index I and Allergy Index II were significantly correlated with each other (rs = 0.98, p less than 0.001) and with the number of positive skin-test reactions (rs congruent to 0.9, p less than 0.001) as well as with log[total serum IgE] (r congruent to 0.4, p less than 0.01). In 102 ragweed-positive subjects, log[specific IgE to ragweed] was significantly correlated with ragweed-specific "ragweed indices I and II" (r congruent to 0.6, p less than 0.01). Furthermore, the average daily symptom scores reported by 14 ragweed-positive subjects during the ragweed pollination season were significantly correlated with ragweed indices I and II (p less than 0.05). We propose the use of Allergy Index II in epidemiologic and genetic studies of allergic phenotypes as well as in clinical decisions for diagnosis and immunotherapeutic intervention.

Adult↗
PubMed2006

Study of the near-neutral pH-sensitivity of chitosan/gelatin hydrogels by turbidimetry and microcantilever deflection.

The fundamental properties and pH-sensitivity of chitosan/gelating hydrogels were investigated using spectroscopic and microelectro mechanical (MEMS) measurement approaches. Turbidimetric titration revealed that there were electrostatic attractive interactions between tripolyphosphate (TPP), chitosan, and gelatin in the acidic pH range, depending on their degree of ionization. The pH-sensitive swelling behavior of the hydrogels was investigated by monitoring the deflection of hydrogel-coated microcantilevers, which exhibited a sensitive and repeatable response to solution pH. The deflection of the microcantilever increased as the pH decreased, and the response speed of the system exhibited a nearly linear relationship with pH. The effects of the pH and concentration of TPP solution, as well as the ratio of chitosan to gelatin in gel precursor solutions, on the pH sensitivity of the hydrogels were also investigated. It was found that the swelling of the hydrogel is mainly a result of chain relaxation of chitosan-TPP complexes caused by protonation of free amino groups in chitosan, which depends on the crosslinking density set during the formation of the network. An increase in initial crosslink density induced a decrease in swelling and pH sensitivity. It can be concluded from this study that pH-sensitive chitosan gel properties can be tuned by preparatory conditions and inclusion of gelatin. Furthermore, microcantilevers can be used as a platform for gaining increased understanding of environmentally sensitive polymers.

Biosensing Techniques↗
PubMed2005

Nonlinear optical chromophores as nanoscale emitters for single-molecule spectroscopy.

Fluorescence imaging of single molecules at room temperature is a powerful technique for studying complex condensed phase systems and revealing structure and dynamics hidden by ensemble measurements. Successful single-molecule spectroscopic experiments rely upon strong emitters that can be detected at the level of individual copies above the relevant background signals. This Account discusses a class of nonlinear optical chromophores that not only are well-suited for single-molecule imaging but also offer additional beneficial properties such as a significant ground-state dipole moment, moderate hyperpolarizability, and sensitivity to local environment. An overview of the photophysical properties of several members of this class of molecules as well as a mechanism to help understand the environmental sensitivity is presented. Some preliminary applications of the chromophores as single-molecule reporters in cellular and polymer systems are discussed, along with detection of the emitters by two-photon fluorescence.

Fluorescent Dyes↗
PubMed2003

Breathing and heart rate during experimental solvent exposure of young adults with self-reported multiple chemical sensitivity (sMCS).

This paper deals with the assumption that young adults with self-reported multiple chemical sensitivity (sMCS) show a heightened sensitivity of autonomic functions during experimental solvent exposure. Male sMCS-subjects were selected (out of n=274) on the base of a German questionnaire on chemical and environmental sensitivity (CGES). Two independent experiments were carried out, each with 12 sMCS-subjects and 12 age-matched control-subjects. In experiment I two concentrations of the solvents ethyl benzene (10 and 98 ppm) and 2-butanone (10 and 189 ppm) were used. Experiment II investigated 2-propanol (35 and 190 ppm) and 1-octanol (0.1 and 6.4 ppm). The low concentrations correspond nearly to the olfactory thresholds while the high concentrations correspond to the German occupational threshold limit values (MAC). The exposure duration under each condition was 4h. The sequence of the four exposure conditions was random including intervals of at least 2 days without exposure. During the exposure physiological changes of breathing rate and heart rate were recorded. Two 30 min intervals with a sedentary position of the subjects at the beginning and end of exposure were chosen for analyses. Neither in experiment I nor in experiment II significant specific reactions to the type or level of the exposures were found. The autonomic functions in both experiments revealed alterations within the exposure sessions. The heart rate in experiment II and the breathing rate in both experiments decreased significantly during the analyzed 30 min intervals. Furthermore, in both experiments the heart rates decreased significantly from beginning to end of exposure. Only in experiment I the mean breathing rate of sMCS-subjects was generally higher compared to the control-subjects. Regarding the assumption of a heightened sensitivity of sMCS-subjects the two experiments yielded controversial results. Thus, the hypothesis of stronger responses of autonomic functions of sMCS-subjects provoked by various exposure scenarios remains open.

Adult↗
PubMed2025

Genetic Susceptibility to the Environment Moderates the Impact of Childhood Experiences on Psychotic, Depressive, and Anxiety Dimensions.

BACKGROUND AND HYPOTHESIS: Gene-by-environment (GxE) studies in psychosis have exclusively focused on negative exposures. However, evidence supports the resilience-enhancing effect of positive factors on psychosis outcome. The Differential Susceptibility (DS) model proposes that common genetic variants may confer not only disproportionate responsiveness to negative environments, but also greater sensitivity to positive, resilience-enhancing conditions. This study is the first to apply the DS model to the expression of subclinical psychosis, employing polygenic risk scores of environmental sensitivity (PRS-ES). PRS-ES were hypothesized to moderate, in a DS manner, associations between childhood adversity and psychosis, affective, and anxiety dimensions in young adults. An exploratory goal examined whether PRS for psychotic-like experiences (PRS-PLE) also showed DS patterns. STUDY DESIGN: PRS, schizotypy, PLE, depression, anxiety, and childhood adversity ratings were obtained for 197 nonclinical young adults. LEGIT software for testing competitive-confirmatory GxE models was employed. STUDY RESULTS: Results largely supported DS: Individuals high on PRS-ES showed increased subclinical psychosis, depression, and anxiety if they had experienced elevated childhood adversity, and lower symptoms if exposed to low levels of adversity as compared with those with low PRS-ES. Similarly, PRS-PLE moderated the effect of adversity on PLE, positive schizotypy, and depression following the DS model, but only PRS-ES moderation on PLE survived statistical correction. CONCLUSIONS: Our results suggest that genetic DS to the environment is relevant to psychosis, depression, and anxiety. Current debates on reconceptualization of genetic "risk" and resilience may benefit from this insight that support optimistic views on preventative efforts for early detection and intervention.

Humans↗
PubMed2005

Psychosocial factors as risk indicators of periodontitis.

OBJECTIVE: Cross-sectional investigation of associations between psychosocial and periodontal parameters. METHODS: One hundred and ten patients 18-76 years of age were examined clinically and 57 radiographically at the Department of Conservative Dentistry of the University Hospital of Heidelberg: probing depths (PDs) and attachment level (PAL-V) were obtained at six sites per tooth. Inter-proximal bone loss was assessed in 57 patients on panoramic radiographs. Further chemical and general environmental sensitivity, somatization, and smoking status were assessed by several questionnaires. RESULTS: Significant correlations between severe bone loss and age (r=0.38, p=0.004) were observed. PAL-V and PD also correlated with age (r=0.45, p<0.001; r=0.37, p<0.001) and pack years (r=0.21, p=0.031; r=0.3, p=0.002). After adjustment for age, smoking, and sex a negative correlation between chemical odour sensitivity and bone loss, PD=4 mm as well as PAL-V=4 mm was observed. Further, a negative correlation was observed between gastrointestinal sensitivity and PAL-V=4 mm. Psychological stress correlated positively with bone loss. CONCLUSION: The results give evidence for associations of psychosocial factors and periodontal disease. Some environmental traits seem to be related to more favourable periodontal status.

Adolescent↗
PubMed1989

Spectroscopic studies of the tyrosine residues of human plasma apolipoprotein A-II.

Human apolipoprotein A-II (apo A-II) in solution and associated with 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) was investigated by a combination of absorbance and fluorescence methods. Each apo A-II polypeptide chain contains four tyrosine residues but no tryptophan residues. Two and three tyrosine residues, respectively, appear to be buried for apo A-II in aqueous solution and in the lipid-associated protein. The spectroscopic properties of the tyrosine residues of lipid-associated apo A-II were also investigated. Plots of fluorescence intensity against temperature revealed a discontinuity in the region of the phase transition; however, over the same temperature range, there was no change in the exposure of tyrosine residues to the aqueous environment or in their mobility as measured by fluorescence polarization. Near-ultraviolet circular dichroic measurements demonstrated that the environments of the tyrosine residues of lipid-associated apo A-II and nitrated apo A-II were different from that of the apo A-II in solution or in a denatured state. Similar measurements also revealed that the microenvironments around tyrosines of apo A-II bound to DMPC in the gel phase are different from those observed in the liquid crystalline phase. Using environmentally sensitive fluorescence lipid probes, we have previously demonstrated that the polarity of the lipid/water interface of DMPC changes through a phase transition. The observations presented here indicate that these environmental changes also occur at the lipid/protein interface.

Amino Acid Sequence↗
PubMed1997

Transmembrane beta-barrel of staphylococcal alpha-toxin forms in sensitive but not in resistant cells.

Staphylococcal alpha-toxin is a 293-residue, single-chain polypeptide that spontaneously assembles into a heptameric pore in target cell membranes. To identify the pore-forming domain, substitution mutants have been produced in which single cysteine residues were introduced throughout the toxin molecule. By attaching the environmentally sensitive dye acrylodan to the sulfhydryl groups, the environment of individual amino acid side chains could be probed. In liposomes, a single 23-amino acid sequence (residues 118-140) was found to move from a polar to a nonpolar environment, indicating that this sequence forms the walls of the pore. However, periodicity in side chain environmental polarity could not be detected in the liposomal system. In the present study, the fluorimetric analyses were extended to physiological target cells. With susceptible cells such as rabbit erythrocytes and human lymphocytes, the 23 central amino acids 118-140 were again found to insert into the membrane; in contrast to the previous study with liposomes, the expected periodicity was now detected. Thus, every other residue in the sequence 126-140 entered a nonpolar environment in a striking display of an amphipathic transmembrane beta-barrel. In contrast, human granulocytes were found to bind alpha-toxin to a similar extent as lymphocytes, but the heptamers forming on these cells failed to insert their pore-forming domain into the membrane. As a consequence, nonfunctional heptamers assembled and the cells remained viable. The data resolve the molecular organization of a pore-forming toxin domain in living cells and reveal that resistant cells can prevent insertion of the functional domain into the bilayer.

Adenosine Triphosphate↗
PubMed2025

Genetic Differences in Reactivity to the Environment Impact Psychotic-Like and Affective Reactivity in Daily Life.

BACKGROUND AND HYPOTHESIS: Consistent with diathesis-stress models, psychosis research has focused on genetic moderation of adverse environmental exposures. In contrast, the Differential Susceptibility (DS) model suggests that the same genetic variants that increase risk-inducing effects of adverse experiences also enhance beneficial effects from positive experiences. This study examined whether individuals with high genetic susceptibility to the environment showed differential psychotic-like and affective reactivity in response to positive and negative events in daily life. STUDY DESIGN: Experience sampling methodology assessed context (positive and stressful) and momentary levels of paranoia, psychotic-like experiences (PLE), and positive (PA) and negative affect (NA) in 217 non-clinical adults oversampled for schizotypy. Linear mixed models examined whether Polygenic Risk Scores of Environmental Sensitivity (PRS-ES) moderated the impact of current context on subsequent experiences. STUDY RESULTS: PRS-ES moderated positive, but not stressful, context on subsequent levels of momentary paranoia, NA, and PA, but not PLE. Genetic and environmental (G&#x2005;&#xd7;&#x2005;E) interactions indicated diathesis-stress at lower thresholds of PRS-ES, but a DS model at the highest threshold of the PRS-ES. Participants with elevated PRS-ES showed increased paranoia and NA and decreased PA in subsequent assessments when reporting low levels of positive situations, but also decreased paranoia and NA and increased PA when rating contexts as positive. CONCLUSIONS: Findings support the influence of genetic sensitivity to the environment on psychotic-like and affective reactivity in daily life, particularly in response to positive contexts. This highlights the transdiagnostic protective role of positive experiences and informs ecological momentary interventions.

Humans↗
PubMed2003

C2 domain of protein kinase C alpha: elucidation of the membrane docking surface by site-directed fluorescence and spin labeling.

The C2 domain is a conserved signaling motif that triggers membrane docking in a Ca(2+)-dependent manner, but the membrane docking surfaces of many C2 domains have not yet been identified. Two extreme models can be proposed for the docking of the protein kinase C alpha (PKC alpha) C2 domain to membranes. In the parallel model, the membrane-docking surface includes the Ca(2+) binding loops and an anion binding site on beta-strands 3-4, such that the beta-strands are oriented parallel to the membrane. In the perpendicular model, the docking surface is localized to the Ca(2+) binding loops and the beta-strands are oriented perpendicular to the membrane surface. The present study utilizes site-directed fluorescence and spin-labeling to map out the membrane docking surface of the PKC alpha C2 domain. Single cysteine residues were engineered into 18 locations scattered over all regions of the protein surface, and were used as attachment sites for spectroscopic probes. The environmentally sensitive fluorescein probe identified positions where Ca(2+) activation or membrane docking trigger measurable fluorescence changes. Ca(2+) binding was found to initiate a global conformational change, while membrane docking triggered the largest fluorescein environmental changes at labeling positions on the three Ca(2+) binding loops (CBL), thereby localizing these loops to the membrane docking surface. Complementary EPR power saturation measurements were carried out using a nitroxide spin probe to determine a membrane depth parameter, Phi, for each spin-labeled mutant. Positive membrane depth parameters indicative of membrane insertion were found for three positions, all located on the Ca(2+) binding loops: N189 on CBL 1, and both R249 and R252 on CBL 3. In addition, EPR power saturation revealed that five positions near the anion binding site are partially protected from collisions with an aqueous paramagnetic probe, indicating that the anion binding site lies at or near the surface of the headgroup layer. Together, the fluorescence and EPR results indicate that the Ca(2+) first and third Ca(2+) binding loops insert directly into the lipid headgroup region of the membrane, and that the anion binding site on beta-strands 3-4 lies near the headgroups. The data support a model in which the beta-strands are tilted toward the parallel orientation relative to the membrane surface.

Amino Acid Substitution↗
PubMed2001

A GIS planning model for urban oil spill management.

Oil spills in industrialized cities pose a significant threat to their urban water environment. The largest city in Canada, the city of Toronto, has an average 300-500 oil spills per year with an average total volume of about 160,000 L/year. About 45% of the spills was eventually cleaned up. Given the enormous amount of remaining oil entering into the fragile urban ecosystem, it is important to develop an effective pollution prevention and control plan for the city. A Geographic Information System (GIS) planning model has been developed to characterize oil spills and determine preventive and control measures available in the city. A database of oil spill records from 1988 to 1997 was compiled and geo-referenced. Attributes to each record such as spill volume, oil type, location, road type, sector, source, cleanup percentage, and environmental impacts were created. GIS layers of woodlots, wetlands, watercourses, Environmental Sensitive Areas, and Areas of Natural and Scientific Interest were obtained from the local Conservation Authority. By overlaying the spill characteristics with the GIS layers, evaluation of preventive and control solutions close to these environmental features was conducted. It was found that employee training and preventive maintenance should be improved as the principal cause of spills was attributed to human errors and equipment failure. Additionally, the cost of using oil separators at strategic spill locations was found to be $1.4 million. The GIS model provides an efficient planning tool for urban oil spill management. Additionally, the graphical capability of GIS allows users to integrate environmental features and spill characteristics in the management analysis.

Cities↗
PubMed1975

Land use and transportation issues in environmental control.

Analyses have been made of the effects of environmental controls and planning at regional, subarea, and project levels. The results obtained at the regional level are reviewed for a proposed highway development around Baltimore, Md. The findings for both short-term and long-term effects of alternative transport policies are summarized in respect of population and employment, economic indicators, traffic and travel, air quality, water and solid waste, noise, and environmentally sensitive areas. Problems at subarea and project levels are briefly considered.

Air Pollution↗
PubMed2004

In vivo targeting of organic calcium sensors via genetically selected peptides.

A library of constrained peptides that form stable folded structures was screened for aptamers that bind with high affinity to the fluorescent dye Texas red. Two selected clones had binding constants to Texas red of 25 and 80 pM as phage and binding had minimal effects on the fluorescence of Texas red. The peptides interact with distinct but overlapping regions of Texas red. One peptide bound to X-rhod calcium sensors, which share the same core fluorophore as Texas red. These dyes retained calcium sensitivity when bound to the peptide. This peptide was used to label a fusion protein with X-rhod-5F in vivo, and X-rhod sensed changes in calcium locally. Thus, minimal, constrained peptides can functionally bind to environmentally sensitive dyes or other organic agents in biological contexts, suggesting tools for in vivo imaging and analysis.

Amino Acid Sequence↗
PubMed1995

Use of resonance energy transfer to determine the proximity of the guanine nucleotide binding site of transducin relative to a conformationally-sensitive site on the gamma subunit of the cyclic GMP phosphodiesterase.

In this work, we have used resonance energy transfer to determine the relative positions of a reactive cysteine residue on the gamma subunit of the retinal cyclic GMP phosphodiesterase (gamma PDE) and a reactive lysine residue on the alpha subunit of transducin (alpha T). The single cysteine residue on gamma PDE (residue 68) is located at a site that is sensitive to the binding of both the inactive and active forms of alpha T. This is demonstrated by the finding that the addition of an alpha T-GDP complex to a gamma PDE subunit labeled with the environmentally-sensitive probe 2-(4-maleimidoanilino)naphthalene-6-sulfonate (MIANS) results in an enhancement in the MIANS fluorescence. The alpha TGDP-induced fluorescence enhancement is dose-dependent and yields an apparent Kd value of approximately 3 microM. Activation of alpha TGDP by aluminum fluoride, when bound to the MIANS-labeled gamma PDE (M-gamma PDE), then results in a quenching of the MIANS fluorescence. The aluminum fluoride-induced change in M-gamma PDE fluorescence occurs on a time scale identical to that observed for changes in the intrinsic alpha T fluorescence that correspond to activating conformational changes in the alpha T "switch II" region. These results suggest that the induction of the activated state of the alpha T subunit results in a change in conformation close to cysteine 68 in gamma PDE.(ABSTRACT TRUNCATED AT 250 WORDS)

3',5'-Cyclic-GMP Phosphodiesterases↗
PubMed2001

Position of the American Dietetic Association: dietetics professionals can implement practices to conserve natural resources and protect the environment. (Previously titled "natural resource conservation and waste management").

It is the position of the American Dietetic Association to encourage environmentally responsible practices that conserve natural resources, minimize the quantity of waste that is generated, and have the least adverse affect on the health of all living organisms and the environment. All components of the food system, from farmer to consumer, are affected by the availability and cost of energy and the availability and quality of water. Outdoor and indoor air quality significantly impacts the health of all living organisms. Decisions that dietetics professionals make as practitioners and consumers can affect the quantity and type of solid waste generated. The demand for natural resources should be evaluated when selecting the most cost-effective, environmentally sensitive approach to the management of solid waste. Special precautions are needed when using and disposing of hazardous and medical waste to protect the safety of our clients and employees. This position paper provides information and resources for dietetics professionals for addressing the complexity of the environmental issue presented. Conservation strategies are identified that dietetics professionals can use in their worksites and at home. These conservation practices may reduce cost and decrease the environmental impact we have on our communities and the world.

Air Pollution↗
PubMed1998

Location of the membrane-docking face on the Ca2+-activated C2 domain of cytosolic phospholipase A2.

Docking of C2 domains to target membranes is initiated by the binding of multiple Ca2+ ions to a conserved array of residues imbedded within three otherwise variable Ca2+-binding loops. We have located the membrane-docking surface on the Ca2+-activated C2 domain of cPLA2 by engineering a single cysteine substitution at 16 different locations widely distributed across the domain surface, in each case generating a unique attachment site for a fluorescein probe. The environmental sensitivity of the fluorescein-labeled cysteines enabled identification of a localized region that is perturbed by Ca2+ binding and membrane docking. Ca2+ binding to the domain altered the emission intensity of six fluoresceins in the region containing the Ca2+-binding loops, indicating that Ca2+-triggered environmental changes are localized to this region. Similarly, membrane docking increased the protonation of six fluoresceins within the Ca2+-binding loop region, indicating that these three loops also are directly involved in membrane docking. Furthermore, iodide quenching measurements revealed that membrane docking sequesters three fluorescein labeling positions, Phe35, Asn64, and Tyr96, from collisions with aqueous iodide ion. These sequestered residues are located within the identified membrane-docking region, one in each of the three Ca2+-binding loops. Finally, cysteine substitution alone was sufficient to dramatically reduce membrane affinity only at positions Phe35 and Tyr96, highlighting the importance of these two loop residues in membrane docking. Together, the results indicate that the membrane-docking surface of the C2 domain is localized to the same surface that cooperatively binds a pair of Ca2+ ions, and that the three Ca2+-binding loops themselves provide most or all of the membrane contacts. These and other results further support a general model for the membrane specificity of the C2 domain in which the variable Ca2+-binding loops provide headgroup recognition at a protein-membrane interface stabilized by multiple Ca2+ ions.

Amino Acid Substitution↗
PubMedDate not supplied

Clinical waste generation from renal units: implications and solutions.

The treatment of end-stage renal disease (ESRD) makes extensive use of presterilized disposable items which, after use, are contaminated by blood. The preferred route of disposal of such items is by incineration. Disposal costs have risen and this increase in costs has not been matched by waste management programs in renal units. Many of the waste items generated also contain polyvinyl chloride (PVC) whose incineration is environmentally sensitive. Furthermore blood tubing sets contain plasticizers such as di(2-ethylhexyl) phthalate (DEHP), which is known to pose health risks to specific groups of patients. The generation of clinical waste in a dialysis unit is analyzed, issues associated with disposal are discussed, and approaches toward a cost-effective, environmentally sustainable clinical waste management program are reviewed.

Cost-Benefit Analysis↗
PubMed1993

Response of bone and enamel formation to nutritional supplementation and morbidity among malnourished Guatemalan children.

The effects of changes in nutritional and health status upon bone and enamel development are examined in a sample of 63 rural Guatemalan children (24 females, 39 males). The number of ossified hand-wrist centers at 3 years and the number of linear enamel hypoplasias (LEH) in approximately 0-3 year zones of developing teeth were used to monitor the response of bone mineralization and enamel matrix formation to illness and nutritional supplementation. Numbers of ossified centers and LEH were compared across sex, supplementation, and morbidity groups. Enamel matrix secretion responded positively to increased supplementation. Children who received less than 34.25 kcal/day in supplement had more LEH than those who received more supplement. No differences in ossification status were found between supplementation groups. These data suggest that enamel formation may be more sensitive to changes in nutritional status than is bone mineralization. Disruptions of bone and enamel formation were both associated with frequent illness. Children who were ill more than 3.6% of the time had more LEH and fewer ossified hand-wrist centers than children who were less frequently ill. Conclusions regarding relative environmental sensitivity must take into account the specific aspects of dental and skeletal development examined.

Age Factors↗