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PubMedDate not supplied

Effects of an S6 strain of Mycoplasma gallisepticum challenge before beginning of lay on various egg characteristics in commercial layers.

Mycoplasma gallisepticum (MG) is a reproductive/respiratory disease in poultry implicated in suboptimum egg production and decreased hatchability. Commercial layer hens raised in a controlled environment were inoculated with the S6 strain of MG at 10 wk of age. Egg production and selected egg and egg quality parameters were quantitated over the entire lay cycle for inoculated and control birds. The S6 inoculation had no effect on bird weight, egg production, associated egg quality parameters, or histopathologic lesion scores. This study shows that in the absence of environmental stressors a prelay S6 MG inoculation does not produce detrimental effects on layer hen performance.

Animals↗

PubMed2003

Bright cyclic rearing protects albino mouse retina against acute light-induced apoptosis.

PURPOSE: Previous studies have shown that albino rats born and raised in bright cyclic light are protected from light-induced apoptosis. The present study was designed to determine if bright cyclic rearing provides protection against retinal degeneration caused by acute light exposure in albino mice. METHODS: BALB/c mice were born in dim cyclic light (5 lux, 12 h ON/OFF). At 1 week of age, half of the litters were moved into 400 lux cyclic light. At 5 weeks of age, mice raised in the dim or bright cyclic conditions were divided into two groups. One group was placed in constant light (3,000 lux for 72 h) and the other was maintained in its original cyclic light environment. Control and constant light-stressed mice were dark-adapted for 24 and 48 h, respectively, after which their eyes were removed immediately for morphologic evaluation or preparation of rod outer segment (ROS) membranes. ROS lipids were extracted and fatty acid methyl esters were analyzed by gas-liquid chromatography. Eyes used for TUNEL (terminal deoxynucleotidyl transferase mediated dUTP nick end labeling) and DNA fragmentation assays were enucleated immediately after the 72 h light exposure. RESULTS: Measurement of outer nuclear layer (ONL) thickness indicated there was no difference in the number of viable photoreceptor cells in the dim-reared controls compared to bright-reared controls. Constant light exposure significantly reduced the ONL thickness in dim- and bright-reared groups, with the largest change occurring in the dim-reared mice. TUNEL assay showed no apoptotic photoreceptor cells in either control group; however, apoptotic nuclei could be detected in both exposed groups, with the largest number found in the dim-reared mice. After light exposure, DNA fragmentation was prominent in dim-reared mice, but was not present in bright-reared animals. There was no significant difference in the fatty acid composition of ROS membranes in the dim- and bright-reared control mice. However, constant light exposure resulted in a greater loss of docosahexaenoic acid (22:6n-3) in the ROS of dim-reared animals. CONCLUSIONS: Mice raised in a bright cyclic light environment are protected against light-induced apoptosis. We suggest that the protection is due to the up-regulation of cell survival pathways or the down-regulation of pathways that are vulnerable to acute cell stress.

Adaptation, Ocular↗

PubMed2005

The effects of systemic hypoxia on colon anastomotic healing: an animal model.

PURPOSE: Acute postoperative systemic hypoxia occurs frequently in the clinical setting following intestinal resection, as a result of complications such as pneumonia, pulmonary edema, or the acute respiratory distress syndrome. Although it is well established that oxygen is essential for metabolism in general and intestinal anastomotic healing, the mechanisms by which systemic hypoxia affect this process are not clear. The purpose of this study was to establish an animal model to simulate acute systemic hypoxia and to examine the effects on anastomotic healing. We investigated the hypothesis that systemic hypoxia impairs anastomotic healing in the colon by disrupting revascularization via changes in the expression of two putative angiogenic factors: inducible nitric oxide synthase and vascular endothelial growth factor. METHODS: Phase I: Juvenile male Sprague-Dawley rats underwent carotid artery cannulation. In a controlled environment the FiO2 was incrementally decreased from 21 to 9 percent and the resultant PaO2 measured. Phase II: Animals underwent colonic transection with immediate reanastomosis and were placed in either a normoxic (FiO2 21 percent) or hypoxic (FiO2 11 percent) environment for seven days. Perianastomotic in vivo tissue oxygen saturation was measured before segmental colon resection in each of the animals and at seven days before measurement of anastomotic bursting pressure. Perianastomotic tissue samples were assessed by Western blot assay for the expression of vascular endothelial growth factor and inducible nitric oxide synthase protein. Sections from each tissue sample were taken and evaluated by a pathologist blinded to treatment group for determination of anastomotic healing score. RESULTS: Phase I: Incrementally decreasing the FiO2 resulted in a progressive decrease in PaO2 (r2 = 0.77). Phase II: Animals maintained in a hypoxic environment had a significant decrease in tissue oxygen saturation (73 +/- 9 percent vs. 94 +/- 3 percent; P < 0.0001) and anastomotic bursting pressure (118 +/- 18 mmHg vs. 207 +/- 30 mmHg; P < 0.0001) compared with normoxic controls. Systemic hypoxia induced a significant increase, when compared with normoxic controls, in vascular endothelial growth factor (247.1 +/- 9.5 vs. 142.2 +/- 10.6; P < 0.0001) and inducible nitric oxide synthase (259.6 +/- 21.1 vs. 120.2 +/- 10.9; P < 0.0001) protein expression and led to a significant decrease in the overall wound-healing score. CONCLUSION: This study validates a new animal model to study the effects of acute systemic hypoxia on colonic anastomotic healing. In this model, systemic hypoxia directly translated into local tissue hypoxia, and anastomotic healing was impaired. Contrary to our original hypothesis, hypoxia led to a significant increase in vascular endothelial growth factor and inducible nitric oxide synthase protein expression at the colonic anastomotic site. Impairment in anastomotic integrity despite upregulation of these angiogenic factors could be a result of the inability of wounded tissue to respond to vascular endothelial growth factor and inducible nitric oxide synthase or alternatively, hypoxia may adversely affect collagen synthesis and deposition directly.

Anastomosis, Surgical↗

PubMedDate not supplied

Effects of a high-starch diet with low or high fiber content on postabsorptive glucose utilization and glucose production in normal subjects.

The effects of fiber, added to a high-starch diet, on glucose and insulin metabolism were studied in seven healthy men in a controlled environment. Diets rich in starch (carbohydrate provided 62% energy) contained either 16 g or 100 g of fiber from several sources of food and were given for 10-day periods. Two parameters of glucose control were measured: glucose metabolism during insulin-glucose infusions (seven subjects) and glucose production measured by infusing tritiated glucose tracer (five subjects). Three sets of studies were carried out in the sequence: low-fiber, high-fiber, low-fiber. The respective mean values (+/- SE) for glucose utilization were 6.70 +/- 1.4, 7.01 +/- 1.02, and 6.77 +/- 1.34 mg/kg X min. Analysis of variance failed to show a significant effect of dietary change. Values for basal glucose production were 2.0 +/- 0.1, 1.9 +/- 0.2, and 2.4 +/- 0.3 mg/kg X min with the low-fiber, high-fiber, and low-fiber diets, respectively, which were not significantly different. The one significant response to the high-fiber diet was a lowering in plasma cholesterol, the mean values for the seven subjects during the three periods being 154 +/- 12, 138 +/- 10, and 156 +/- 13 mg/dl (P less than 0.05).

Adult↗

PubMed1995

[Technical aids to patients with spinal cord injuries].

The purpose of technical aids is to compensate temporary and especially definitive functional disabilities in handicapped people. In medullary injured patients, technical aids are essential to preserve as much as possible the independence of paraplegics and particularly tetraplegic patients--activities of daily life such as eating, toileting, dressing, ambulation, car-driving, writing and environment control become hence forward possible. Technical aids prescription and adaptations depend for a large part not only on the localization of the lesion of the trauma but also of the goals, motivations and the environment of the disabled person.

Humans↗

PubMed1978

[Insurance and preventive medicine].

Not only do insurance companies have to pay in case of death, injuries or disease, they are also concerned with their prevention. This is particularly true for the "Swiss National Accident Insurance Fund" (Caisse nationale suisse d'assurance en cas d'accidents--(CNA): for them the prevention of work related accidents and occupational diseases is required by law. Preventive activities in this area are very promising. The progress in the sickness insurance programmes for preventive medicine in the general population has, however, not been as successful. To date, the legislation denies payment for preventive medical care. Why is there this difference? In the case of accidents and occupational diseases, the cause of the pathologies are for the most part exogenous and develop in well known and controlled environments. In the case of disease or invalidity in the general population, the factors are in a large part endogenous and therefore very difficult to supervise, as they develop in much more complex and uncontrolled environments. Nevertheless progress has been done in this field as well. At present, some selected scientifically proven preventive examinations could be included in insurance programmes as part of a general plan and with strict quality control of laboratory findings.

Accidents, Occupational↗

PubMed2004

Novel spatial arrangements of familiar visual stimuli promote activity in the rat hippocampal formation but not the parahippocampal cortices: a c-fos expression study.

The novelty of a cue may arise from the presence of an element that has not previously been experienced or from familiar elements that have been rearranged. The present study mapped the anatomical basis of responding to this second form of novelty. For this, rats were trained on a working memory spatial task in a radial-arm maze in a cue-controlled environment. On the final test day the positions of the familiar, extra-maze cues were rearranged for half of the rats (group Novel). The spatial configuration of the cues now matched that of the control rats (group Familiar). Neuronal activation, as measured by the immediate early gene, c-fos, was then compared between the two groups. Rearrangement of visual stimuli led to significant increases in Fos-positive cells in various hippocampal subfields (rostral CA1, rostral CA3 and rostral dentate gyrus) as well as the parietal cortex and the postsubiculum. In contrast, no changes were observed in other sites including the perirhinal cortex, postrhinal cortex, lateral and medial entorhinal cortices, retrosplenial cortices, or anterior thalamic nuclei. These results highlight the selective involvement of the hippocampus for processing novel rearrangements of visual stimuli and suggest that this involvement is intrinsic as it is independent of the parahippocampal cortices. This pattern of Fos changes is the mirror image of that repeatedly found for novel individual stimuli (perirhinal increase, no hippocampal change), demonstrating that these two forms of novelty have qualitatively different neural attributes.

Animals↗

PubMed1996

Group selection for adaptation to multiple-hen cages: humoral immune response.

A selected line of White Leghorns, which has shown improved survivability and reduced feather loss in large multiple-hen cages, was evaluated for humoral immune response to SRBC under both stressed and unstressed conditions. Three lines of chickens (selected, control, and commercial) were housed in either single- (1 hen) or multiple-hen cages (12 hens, social competition) and subjected to a cold ambient temperature (0 C) at 33 wk of age and to two heating episodes (38 C) at 44 wk of age. Each hen was challenged intravenously with 1 mL of a 7% saline suspension of SRBC at the time that cold exposure was initiated. Hens subjected to high ambient temperatures had been exposed previously to a cold temperature, but were not challenged with SRBC until 16 to 18 h following the end of the second heating episode. Exposure to cold caused immunosuppression in single-caged hens, but not in hens in colony cages. Single- vs colony-caged hens of the control environment challenged with SRBC at 33 wk of age had similar primary hemagglutinin responses to SRBC. Hens subjected to heat experienced immunosuppression at 9 and 12 d following challenge to SRBC when compared to the controls. Hens of multiple-bird cages challenged with antigen at 44 wk of age had a significantly lower hemagglutinin response to SRBC than those reared in single-bird cages. The three lines of genetic stock had similar primary hemagglutinin responses to SRBC; the interactions of genetic stock with cage size or environmental temperature were not significant. It was concluded that genetically selecting hens for survival in multiple-hen cages did not affect their humoral immune response to SRBC.

Adaptation, Physiological↗

PubMedDate not supplied

Material properties of plasticized hardwood xylans for potential application as oxygen barrier films.

Free films based on glucuronoxylan isolated from aspen wood were prepared by casting from aqueous solutions and drying in a controlled environment. Addition of xylitol or sorbitol facilitated film formation and thus examination of the material properties of these films. The mechanical properties of the films were evaluated using tensile testing and dynamic mechanical analysis in a controlled ambient relative humidity. The strain at break increased, and the stress at break and Young's modulus of the films decreased with increasing amounts of xylitol and sorbitol due to plasticization. At high amount of plasticizer, it was found that films with xylitol gave lower extensibility. Wide-angle X-ray scattering analysis showed that xylitol crystallized in a distinct phase, which we believe contributes to the more brittle behavior of these films. The effect of the plasticizers on the glass transition temperature was determined using dynamic mechanical analysis and differential scanning calorimetry. An increased amount of plasticizer shifted the glass transition to lower temperatures. The effect of moisture on the properties of plasticized films was investigated using water vapor sorption isotherms and by humidity scans in dynamic mechanical analysis. Sorption isotherms showed a transition from type II to type III when adding plasticizer. The films showed low oxygen permeability and thus have a potential application in food packaging.

Biocompatible Materials↗

PubMed1997

An investigative model evaluating how consumers process pictorial information on nonprescription medication labels.

Currently, marketed over-the-counter (OTC) medication labels were simulated and tested in a controlled environment to understand consumer evaluation of OTC label information. Two factors, consumers' age (younger and older adults) and label designs (picture-only, verbal-only, congruent picture-verbal, and noncongruent picture-verbal) were controlled and tested to evaluate consumer information processing. The effects exerted by the independent variables, namely, comprehension of label information (understanding) and product evaluations (satisfaction, certainty, and perceived confusion) were evaluated on the dependent variable purchase intention. Intention measured as purchase recommendation was significantly related to product evaluations and affected by the factor label design. Participants' level of perceived confusion was more important than actual understanding of information on OTC medication labels. A Label Evaluation Process Model was developed which could be used for future testing of OTC medication labels.

Adolescent↗

PubMed1984

A model for obtaining predictable natural transmission of rhinoviruses in human volunteers.

A model has been developed in which rhinoviral colds can be predictably transmitted by experimentally infected donors to susceptible recipients in a continuously monitored and controlled environment under simulated natural conditions. Rates of transmission correlated closely (r = .926, P less than .01) with donor-hours of exposure. This model can be used to define routes of transmission, to explore methods of controlling dissemination, to study resistance mechanisms, and to test preventive and therapeutic agents.

Adolescent↗

PubMed1989

Decline of activity and quantity of ribulose bisphosphate carboxylase/oxygenase and net photosynthesis in ozone-treated potato foliage.

The effect of ozone (O(3)) on ribulose bisphosphate carboxylase/oxygenase (Rubisco) activity and quantity and net photosynthesis in greenhouse-grown Solanum tuberosum L. cv ;Norland' foliage was studied in relation to oxidant-induced premature senescence. Plants, 26 days old, were exposed to 0.06 to 0.08 microliters per liter O(3) from 1000 to 1600 hours for 4 days in a controlled environment chamber. On day 5, plants were exposed to a 6-hour simulated inversion in which O(3) peaked at 0.12 microliters per liter. Net photosynthesis declined in response to O(3) but recovered to near control levels 3 days after the exposure ended. Rubisco activity and quantity in control potato foliage increased and then decreased during the 12-day interval of the study. In some experiments foliage studied was physiologically mature and Rubisco activity had peaked when O(3) exposure commenced. In those cases, O(3) accelerated the decline in Rubisco activity. When less mature foliage was treated with O(3), the leaves never achieved the maximal level of Rubisco activity observed in control foliage and also exhibited more rapid decline in initial and total activity. Percent activation of Rubisco (initial/total activity) was not affected significantly by treatment. Quantity of Rubisco decreased in concert with activity. The decrease in activities is most likely due to a decrease in available protein rather than a decrease in the percentage of Rubisco activated in vivo. The reduction in the quantity of Rubisco, an important foliar storage protein, could contribute to premature senescence associated with toxicity of this air pollutant.

Journal Article↗

PubMed2004

Determination of the efficacy of two building decontamination strategies by surface sampling with culture and quantitative PCR analysis.

The efficacy of currently available decontamination strategies for the treatment of indoor furnishings contaminated with bioterrorism agents is poorly understood. Efficacy testing of decontamination products in a controlled environment is needed to ensure that effective methods are used to decontaminate domestic and workplace settings. An experimental room supplied with materials used in office furnishings (i.e., wood laminate, painted metal, and vinyl tile) was used with controlled dry aerosol releases of endospores of Bacillus atrophaeus ("Bacillus subtilis subsp. niger," also referred to as BG), a Bacillus anthracis surrogate. Studies were performed using two test products, a foam decontaminant and chlorine dioxide gas. Surface samples were collected pre- and posttreatment with three sampling methods and analyzed by culture and quantitative PCR (QPCR). Additional aerosol releases with environmental background present on the surface materials were also conducted to determine if there was any interference with decontamination or sample analysis. Culture results indicated that 10(5) to 10(6) CFU per sample were present on surfaces before decontamination. After decontamination with the foam, no culturable B. atrophaeus spores were detected. After decontamination with chlorine dioxide gas, no culturable B. atrophaeus was detected in 24 of 27 samples (89%). However, QPCR analysis showed that B. atrophaeus DNA was still present after decontamination with both methods. Environmental background material had no apparent effect on decontamination, but inhibition of the QPCR assay was observed. These results demonstrate the effectiveness of two decontamination methods and illustrate the utility of surface sampling and QPCR analysis for the evaluation of decontamination strategies.

Air Pollution, Indoor↗

PubMedDate not supplied

An evaluation of a multicomponent treatment program involving scheduled smoking and relapse prevention procedures: initial findings.

In the current study, 34 smokers were treated in a smoking cessation program that involved either a scheduled smoking procedure, or a minimal contact self-help treatment control. The interval smoking program consisted of baseline, cessation, and relapse prevention phases. During baseline, subjects self-monitored smoking and the total hours spent awake. During a 3-week cessation period, the scheduled smoking group progressively increased their intercigarette interval, thereby gradually reducing their total daily intake of nicotine. Smokers were expected to quit on a target date set at the end of this period. Cognitive behavioral interventions and relapse prevention training consisted of behavioral rehearsal of nonsmoking skills in a relapse prone environment. Control subjects were given the American Cancer Society "I Quit Kit", and provided subsequent discussion of its use. The results showed that 53% and 41% of the scheduled smoking group was abstinent at the 6- and 12-month follow-up points, respectively. Controls averaged only 6% for the same periods. Scheduled smoking may be a useful addition to a multicomponent treatment program and further study appears warranted to determine the saliency of the treatment features.

Adult↗

PubMed2006

Movement of proteins in an environment crowded by surfactant micelles: anomalous versus normal diffusion.

Small proteins move in crowded cell compartments by anomalous diffusion. In many of them, e.g., the endoplasmic reticulum, the proteins move between lipid membranes in the aqueous lumen. Molecular crowding in vitro offers a systematic way to study anomalous and normal diffusion in a well controlled environment not accessible in vivo. We prepared a crowded environment in vitro consisting of hexaethylene glycol monododecyl ether (C(12)E(6)) nonionic surfactant and water and observed lysozyme diffusion between elongated micelles. We have fitted the data obtained in fluorescence correlation spectroscopy using an anomalous diffusion model and a two-component normal diffusion model. For a small concentration of surfactant (below 4 wt %) the data can be fitted by single-component normal diffusion. For larger concentrations the normal diffusion fit gave two components: one very slow and one fast. The amplitude of the slow component grows with C(12)E(6) concentration. The ratio of diffusion coefficients (slow to fast) is on the order of 0.1 for all concentrations of surfactant in the solution. The fast diffusion is due to free proteins while the slow one is due to the protein-micelle complexes. The protein-micelle interaction is weak since even in a highly concentrated solution (35% of C(12)E(6)) the amplitude of the slow mode is only 10%, despite the fact that the average distance between the micelles is the same as the size of the protein. The anomalous diffusion model gave the anomaly index (r(2)(t) approximately t(alpha)), alpha monotonically decreasing from alpha = 1 (at 4% surfactant) to alpha = 0.88 (at 37% surfactant). The fits for two-component normal diffusion and anomalous diffusion were of equally good quality, but the physical interpretation was only straightforward for the former.

Buffers↗

PubMed2006

Relationships between community characteristics and municipal smoke-free bylaw status and strength.

BACKGROUND: Municipal smoke-free spaces bylaws are a common population-level intervention to address the prominent health risks associated with exposure to second-hand smoke. In Canada, bylaw prevalence is increasing, but inequities in level of protection across communities remain as bylaws vary from place to place. Little is known about the role of place in this policy disparity. To address this gap, this study examined associations between community characteristics and municipal smoke-free spaces policy outcomes to elucidate how ecological conditions are associated with bylaw status and strength. METHOD: Smoke-free public place and workplace bylaws were obtained from all municipalities with a population of >or=5000 in the provinces of Alberta (N=78) and Ontario (N=245), Canada. Bylaws were assigned a strength score (ranging 0-100) rating the degree of bylaw comprehensiveness, restrictiveness and enforcement provisions. These data were then linked to socio-demographic data from the Canadian Census (1996) and the Canadian Community Health Survey Cycle 1.1 (2000/2001). Logistic and multiple linear regression analyses were used to develop models for municipal bylaw status and strength using community factors including: socio-demographics, municipality type, health region smoking rates, and provincial tobacco control environment. CONCLUSIONS: Study findings suggest that community characteristics play a key role in the status and strength of municipal smoke-free bylaws. As smoking bans continue to emerge world-wide under the Framework Convention on Tobacco Control, knowledge about conditions that promote policy success will be critical for those in need of immediate information to maximize policy-making in their own settings. Use of community profiles that consider socio-demographics along with broader contextual factors can aid decision-makers, public health advocates, and researchers in identifying similar jurisdictions with a successful smoke-free spaces policy and communicating with them about their policy-making experiences. Knowledge about the conditions associated with municipal policy-development may be translated to other jurisdictions where information is sparse, or evidence is newly emerging.

Alberta↗

PubMed1994

A visual programming environment for bioprocess control.

The paper introduces the use of a visual programming environment (LabVIEW) to program custom control functions for bioprocess research. The time taken for a bioprocess scientist to program new functions compared well with typical times expected for experienced programmers using conventional languages. Experienced LabVIEW programmers will develop applications significantly faster. The package described was flexible, easy to use and was ideally suited to developing new applications for control of bioprocesses. It was demonstrated with the development of a system to control specific growth rate in a fed-batch culture.

Recombinant Proteins↗

PubMed2002

Advanced bioreactor with controlled application of multi-dimensional strain for tissue engineering.

Advanced bioreactors are essential for meeting the complex requirements of in vitro engineering functional skeletal tissues. To address this need, we have developed a computer controlled bench-top bioreactor system with capability to apply complex concurrent mechanical strains to three-dimensional matrices independently housed in 24 reactor vessels, in conjunction with enhanced environmental and fluidic control. We demonstrate the potential of this new system to address needs in tissue engineering, specifically toward the development of a tissue engineered anterior cruciate ligament from human bone-marrow stromal cells (hBMSC), where complex mechanical and biochemical environment control is essential to tissue function. Well-controlled mechanical strains (resolution of < 0.1 micron for translational and < 0.1 degree for rotational strain) and dissolved oxygen tension (between 0%-95% +/- 1%) could be applied to the developing tissue, while maintaining temperature at 37 +/- 0.2 degrees C about developing tissue over prolonged periods of operation. A total of 48 reactor vessels containing cell culture medium and silk fiber matrices were run for up to 21 days under 90 degrees rotational and 2 mm translational deformations at 0.0167 Hz with only one succumbing to contamination due to a leak at an medium outlet port. Twenty-four silk fiber matrices seeded with human bone marrow stromal cells (hBMSCs) housed within reactor vessels were maintained at constant temperature (37 +/- 0.2 degrees C), pH (7.4 +/- 0.02), and pO2 (20 +/- 0.5%) over 14 days in culture. The system supported cell spreading and growth on the silk fiber matrices based on SEM characterization, as well as the differentiation of the cells into ligament-like cells and tissue (Altman et al., 2001).

Biomimetics↗