Standing genetic variation and compensatory evolution in transgenic organisms: a growth-enhanced salmon simulation.

Genetically modified strains usually are generated within defined genetic backgrounds to minimize variation for the engineered characteristic in order to facilitate basic research investigations or for commercial application. However, interactions between transgenes and genetic background have been documented in both model and commercial agricultural species, indicating that allelic variation at transgene-modifying loci are not uncommon in genomes. Engineered organisms that have the potential to allow entry of transgenes into natural populations may cause changes to ecosystems via the interaction of their specific phenotypes with ecosystem components and services.

Effect of size fractionation on the toxicity of amosite and Libby amphibole asbestos.

Abnormally high incidences of asbestos-related pulmonary disease have been reported in residents of Libby, Montana, because of occupational and environmental exposure to asbestos-contaminated vermiculite. The mechanism by which Libby amphibole (LA) causes pulmonary injury is not known. The purpose of this study is to compare the cellular stress responses induced in primary human airway epithelial cells (HAECs) exposed to a respirable size fraction (≤ 2.

Vascular effects of ultrafine particles in persons with type 2 diabetes.

Background: Diabetes confers an increased risk for cardiovascular effects of airborne particles.

Objective: We hypothesized that inhalation of elemental carbon ultrafine particles (UFP) would activate blood platelets and vascular endothelium in people with type 2 diabetes.

Methods: In a randomized, double-blind, crossover trial, 19 subjects with type 2 diabetes inhaled filtered air or 50 µg/m³ elemental carbon UFP (count median diameter, 32 nm) by mouthpiece for 2 hr at rest.

Atopic asthmatic subjects but not atopic subjects without asthma have enhanced inflammatory response to ozone.

Background: Asthma is a known risk factor for acute ozone-associated respiratory disease. Ozone causes an immediate decrease in lung function and increased airway inflammation. The role of atopy and asthma in modulation of ozone-induced inflammation has not been determined.

Genetic versus rearing-environment effects on phenotype: hatchery and natural rearing effects on hatchery- and wild-born coho salmon.

With the current trends in climate and fisheries, well-designed mitigative strategies for conserving fish stocks may become increasingly necessary. The poor post-release survival of hatchery-reared Pacific salmon indicates that salmon enhancement programs require assessment. The objective of this study was to determine the relative roles that genotype and rearing environment play in the phenotypic expression of young salmon, including their survival, growth, physiology, swimming endurance, predator avoidance and migratory behaviour.

Effects of temperature and growth hormone on individual growth trajectories of wild-type and transgenic coho salmon Oncorhynchus kisutch.

In this study, individual growth patterns of wild-type and growth-enhanced coho salmon Oncorhynchus kisutch at 8, 12 and 16 degrees C water temperature were followed. Despite large differences among individuals in growth rates, there was generally little variation in the shape of the growth curves among O. kisutch individuals of both genotypes and at all temperatures.

Migration and growth potential of coho salmon smolts: implications for ecological impacts from growth-enhanced fish.

Wild-genotype and growth hormone (GH) transgenic coho salmon (with dramatically enhanced growth potential) were used to examine the influence of genotype, age, body size, growth, and rearing conditions on the onset of seaward migration and to assess the potential consequences of the introduction of such transgenic fish on natural ecosystems and wild populations. When reared from the first feeding stage under naturalized stream conditions, there was no difference in survival or migratory timing between the two genotypes. However, larger fish migrated earlier in the season than smaller fish of both genotypes, and transgenic fish with higher specific spring growth rates migrated earlier in the season than slower-growing transgenic fish.

Does the way physicians are paid influence the way they practice? The case of Canadian family physicians' work activity.

Objectives: To investigate the impact of the mode of remuneration on the work activities of Canadian family physicians on: (a) direct patient care in office/clinic, (b) direct patient care in other settings and (c) indirect patient care.

Methods: Because the mode of remuneration is potentially endogenous to the work activities undertaken by family physicians, an instrumental variable estimation procedure is considered. We also account for the fact that the determination of the allocation of time to different activities by physicians may be undertaken simultaneously.

Growth-related quantitative trait loci in domestic and wild rainbow trout (Oncorhynchus mykiss).

Background: Somatic growth is a complex process that involves the action and interaction of genes and environment. A number of quantitative trait loci (QTL) previously identified for body weight and condition factor in rainbow trout (Oncorhynchus mykiss), and two other salmonid species, were used to further investigate the genetic architecture of growth-influencing genes in this species. Relationships among previously mapped candidate genes for growth and their co-localization to identified QTL regions are reported.

Differential cardiopulmonary effects of size-fractionated ambient particulate matter in mice.

A growing body of evidence from epidemiological and toxicological studies provides a strong link between exposure to ambient particulate matter (PM) of varying size and increased cardiovascular and respiratory morbidity and mortality. This study was designed to evaluate the cardiopulmonary effects of ambient coarse, fine, and ultrafine particles collected in Chapel Hill, NC. Mice were exposed to each size fraction by oropharyngeal instillation.

Comparative airway inflammatory response of normal volunteers to ozone and lipopolysaccharide challenge.

Ozone and lipopolysaccharide (LPS) are environmental pollutants with adverse health effects noted in both healthy and asthmatic individuals. The authors and others have shown that inhalation of ozone and LPS both induce airway neutrophilia. Based on these similarities, the authors tested the hypothesis that common biological factors determine response to these two different agents.

Association of cardiac and vascular changes with ambient PM2.5 in diabetic individuals.

Background And Objective: Exposure to fine airborne particles (PM2.5) has been shown to be responsible for cardiovascular and hematological effects, especially in older people with cardiovascular disease. Some epidemiological studies suggest that individuals with diabetes may be a particularly susceptible population.

Gene expression profile in circulating mononuclear cells after exposure to ultrafine carbon particles.

Context: Exposure to particulate matter (PM) is associated with systemic health effects, but the cellular and molecular mechanisms are unclear.

Objective: We hypothesized that, if circulating mononuclear cells play an important role in mediating systemic effects of PM, they would show gene expression changes following exposure.

Materials And Methods: Peripheral blood samples were collected before (0 h) and at 24 h from healthy subjects exposed to filtered air (FA) and ultrafine carbon particles (UFPs, 50 microg/m(3)) for 2 h in a previous study (n = 3 each).

Low-level ozone exposure induces airways inflammation and modifies cell surface phenotypes in healthy humans.

The effects of low-level ozone exposure (0.08 ppm) on pulmonary function in healthy young adults are well known; however, much less is known about the inflammatory and immunomodulatory effects of low-level ozone in the airways. Techniques such as induced sputum and flow cytometry make it possible to examine airways inflammatory responses and changes in immune cell surface phenotypes following low-level ozone exposure.

Genotype-temperature interaction in the regulation of development, growth, and morphometrics in wild-type, and growth-hormone transgenic coho salmon.

Background: The neuroendocrine system is an important modulator of phenotype, directing cellular genetic responses to external cues such as temperature. Behavioural and physiological processes in poikilothermic organisms (e.g.

Integration of growth hormone gene constructs in transgenic strains of coho salmon (Oncorhynchus kisutch) at centromeric or telomeric sites.

Very little information is currently available regarding the sites of integration of transgenes in genetically engineered fish. We examined the chromosomal location of growth hormone gene constructs containing GH1 in three different strains of transgenic coho salmon produced by microinjection into pronuclei of fertilized eggs. The constructs were labeled and used as probes in fluorescence in situ hybridization experiments on chromosome preparations from the M77, MT5750A, and H3D0474 strains of transgenic coho salmon.

The glutathione-S-transferase Mu 1 null genotype modulates ozone-induced airway inflammation in human subjects.

Background: The glutathione-S-transferase Mu 1 (GSTM1) null genotype has been reported to be a risk factor for acute respiratory disease associated with increases in ambient air ozone levels. Ozone is known to cause an immediate decrease in lung function and increased airway inflammation. However, it is not known whether GSTM1 modulates these ozone responses in vivo in human subjects.

Exposure to concentrated coarse air pollution particles causes mild cardiopulmonary effects in healthy young adults.

Background: There is ample epidemiologic and toxicologic evidence that exposure to fine particulate matter (PM) air pollution [aerodynamic diameter < or = 2.5 microm (PM(2.5))], which derives primarily from combustion processes, can result in increased mortality and morbidity.

Direct particle-to-cell deposition of coarse ambient particulate matter increases the production of inflammatory mediators from cultured human airway epithelial cells.

Exposure of cultured cells to particulate matter air pollution is usually accomplished by collecting particles on a solid matrix, extracting the particles from the matrix, suspending them in liquid, and applying the suspension to cells grown on plastic and submerged in medium. The objective of this work was to develop a more physiologically and environmentally relevant model of air pollutant deposition on cultures of human primary airway epithelial cells. We hypothesize that the toxicology of inhaled particulate matter depends strongly on both the particulate dispersion state and the mode of delivery to cells.

Rapid control of a methicillin resistant Staphylococcus aureus (MRSA) outbreak in a medical surgical intensive care unit (ICU).

Background: Outbreaks of methicillin resistant Staphylococcus aureus in the intensive care unit setting can be prolonged and difficult to control. This report describes the rapid control of an outbreak of methicillin resistant Staphylococcus aureus in a 24-bed open-concept medical surgical intensive care unit with a baseline methicillin resistant Staphylococcus aureus acquisition rate of 1.5 cases per 1000 patient days.

Influence of acid functionalization on the cardiopulmonary toxicity of carbon nanotubes and carbon black particles in mice.

Engineered carbon nanotubes are being developed for a wide range of industrial and medical applications. Because of their unique properties, nanotubes can impose potentially toxic effects, particularly if they have been modified to express functionally reactive chemical groups on their surface. The present study was designed to evaluate whether acid functionalization (AF) enhanced the cardiopulmonary toxicity of single-walled carbon nanotubes (SWCNT) as well as control carbon black particles.

Domestication causes large-scale effects on gene expression in rainbow trout: analysis of muscle, liver and brain transcriptomes.

Domestication has produced faster-growing strains of animals for use in agriculture, but selection has been applied with little knowledge of the underlying genetic changes that arose throughout the process. Mammals and birds have been domesticated for thousands of years whereas fish have been domesticated only recently; therefore, wild progenitor strains remain for comparison. Rainbow trout (Oncorhynchus mykiss) have undergone intensive selection and domesticated strains grow more rapidly than extant wild strains.

Growth hormone transgenesis influences carbohydrate, lipid and protein metabolism capacity for energy production in coho salmon (Oncorhynchus kisutch).

Growth hormone (GH) transgenesis results in increased growth, feed intake and consequent metabolic rates in fish, and alters the utilization of dietary and stored carbohydrates, lipid and protein. However, the manner in which GH transgenesis differentially alters these energy sources in fish has not been well explored. We examined the effects of GH transgenesis and dietary carbohydrate, lipid and protein levels on metabolic enzyme activity in coho salmon (Oncorhynchus kisutch).