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Sample records for repeated controlled exposure

  1. Repeated cocaine exposure facilitates the expression of incentive motivation and induces habitual control in rats.

    Directory of Open Access Journals (Sweden)

    Kimberly H LeBlanc

    Full Text Available There is growing evidence that mere exposure to drugs can induce long-term alterations in the neural systems that mediate reward processing, motivation, and behavioral control, potentially causing the pathological pursuit of drugs that characterizes the addicted state. The incentive sensitization theory proposes that drug exposure potentiates the influence of reward-paired cues on behavior. It has also been suggested that drug exposure biases action selection towards the automatic execution of habits and away from more deliberate goal-directed control. The current study investigated whether rats given repeated exposure to peripherally administered cocaine would show alterations in incentive motivation (assayed using the Pavlovian-to-instrumental transfer (PIT paradigm or habit formation (assayed using sensitivity to reward devaluation. After instrumental and Pavlovian training for food pellet rewards, rats were given 6 daily injections of cocaine (15 mg/kg, IP or saline, followed by a 10-d period of rest. Consistent with the incentive sensitization theory, cocaine-treated rats showed stronger cue-evoked lever pressing than saline-treated rats during the PIT test. The same rats were then trained on a new instrumental action with a new food pellet reward before undergoing a reward devaluation testing. Although saline-treated rats exhibited sensitivity to reward devaluation, indicative of goal-directed performance, cocaine-treated rats were insensitive to this treatment, suggesting a reliance on habitual processes. These findings, when taken together, indicate that repeated exposure to cocaine can cause broad alterations in behavioral control, spanning both motivational and action selection processes, and could therefore help explain aberrations of decision-making that underlie drug addiction.

  2. Repeated cocaine exposure facilitates the expression of incentive motivation and induces habitual control in rats.

    Science.gov (United States)

    LeBlanc, Kimberly H; Maidment, Nigel T; Ostlund, Sean B

    2013-01-01

    There is growing evidence that mere exposure to drugs can induce long-term alterations in the neural systems that mediate reward processing, motivation, and behavioral control, potentially causing the pathological pursuit of drugs that characterizes the addicted state. The incentive sensitization theory proposes that drug exposure potentiates the influence of reward-paired cues on behavior. It has also been suggested that drug exposure biases action selection towards the automatic execution of habits and away from more deliberate goal-directed control. The current study investigated whether rats given repeated exposure to peripherally administered cocaine would show alterations in incentive motivation (assayed using the Pavlovian-to-instrumental transfer (PIT) paradigm) or habit formation (assayed using sensitivity to reward devaluation). After instrumental and Pavlovian training for food pellet rewards, rats were given 6 daily injections of cocaine (15 mg/kg, IP) or saline, followed by a 10-d period of rest. Consistent with the incentive sensitization theory, cocaine-treated rats showed stronger cue-evoked lever pressing than saline-treated rats during the PIT test. The same rats were then trained on a new instrumental action with a new food pellet reward before undergoing a reward devaluation testing. Although saline-treated rats exhibited sensitivity to reward devaluation, indicative of goal-directed performance, cocaine-treated rats were insensitive to this treatment, suggesting a reliance on habitual processes. These findings, when taken together, indicate that repeated exposure to cocaine can cause broad alterations in behavioral control, spanning both motivational and action selection processes, and could therefore help explain aberrations of decision-making that underlie drug addiction.

  3. Microprocessor-controlled inhalation system for repeated exposure of animals to aerosols

    International Nuclear Information System (INIS)

    Carpenter, R.L.; Barr, F.P.; Leydig, R.L.; Rajala, R.E.

    1979-01-01

    A microprocessor-controlled inhalation exposure system (MCIES) has been built to automate aerosol generation and sampling while controlling exposure time for animal toxicity studies. The system has a time resolution of 0.1 s and automatically sequences the exposure events from initiation to temination of the exposure. The operator is required to preset all airflows, read in a paper tape containing the time sequence of events, and initiate the automatic sequence by closing a switch

  4. Baseline repeated measures from controlled human exposure studies: associations between ambient air pollution exposure and the systemic inflammatory biomarkers IL-6 and fibrinogen.

    Science.gov (United States)

    Thompson, Aaron M S; Zanobetti, Antonella; Silverman, Frances; Schwartz, Joel; Coull, Brent; Urch, Bruce; Speck, Mary; Brook, Jeffrey R; Manno, Michael; Gold, Diane R

    2010-01-01

    Systemic inflammation may be one of the mechanisms mediating the association between ambient air pollution and cardiovascular morbidity and mortality. Interleukin-6 (IL-6) and fibrinogen are biomarkers of systemic inflammation that are independent risk factors for cardio-vascular disease. We investigated the association between ambient air pollution and systemic inflammation using baseline measurements of IL-6 and fibrinogen from controlled human exposure studies. In this retrospective analysis we used repeated-measures data in 45 nonsmoking subjects. Hourly and daily moving averages were calculated for ozone, nitrogen dioxide, sulfur dioxide, and particulate matter pollutants on systemic IL-6 and fibrinogen. Effect modification by season was considered. We observed a positive association between IL-6 and O3 [0.31 SD per O3 interquartile range (IQR); 95% confidence interval (CI), 0.080.54] and between IL-6 and SO2 (0.25 SD per SO2 IQR; 95% CI, 0.060.43). We observed the strongest effects using 4-day moving averages. Responses to pollutants varied by season and tended to be higher in the summer, particularly for O3 and PM2.5. Fibrinogen was not associated with pollution. This study demonstrates a significant association between ambient pollutant levels and baseline levels of systemic IL-6. These findings have potential implications for controlled human exposure studies. Future research should consider whether ambient pollution exposure before chamber exposure modifies IL-6 response.

  5. The reinforcing value of vegetables does not increase with repeated exposure during a randomized controlled provided vegetable intervention among overweight and obese adults

    Science.gov (United States)

    Objective: The primary aim of this randomized controlled trial is to determine whether the relative reinforcing value (RRV) of vegetables compared to a snack food can be increased through repeated exposure (incentive sensitization) to amounts of vegetables recommended by the Dietary Guidelines for A...

  6. Effects of repeated skin exposure to low nickel concentrations

    DEFF Research Database (Denmark)

    Nielsen, N H; Menné, T; Kristiansen, J

    1999-01-01

    and nickel allergy, either on normal or on SLS-treated forearm skin. The present study strongly suggests that the changes observed were specific to nickel exposure. Standardized methods to assess trace to moderate nickel exposure on the hands, and the associated effects in nickel-sensitized subjects......We studied the effects of repeated daily exposure to low nickel concentrations on the hands of patients with hand eczema and nickel allergy. The concentrations used were chosen to represent the range of trace to moderate occupational nickel exposure. The study was double-blinded and placebo...... controlled. Patients immersed a finger for 10 min daily into a 10-p.p.m. nickel concentration in water for the first week, and during the second week into a 100-p.p.m. nickel concentration. This regimen significantly increased (P = 0.05) local vesicle formation and blood flow (P = 0.03) as compared...

  7. Toxicological characteristics of petroleum products repeated exposure

    Directory of Open Access Journals (Sweden)

    V.M. Rubin

    2015-03-01

    Full Text Available Abstract. The ability of petroleum products to initiate cumulative effects was assessed in experimental intragastric admission to male albino rats for one month. The analysis of skin-resorptive effects was performed using "test-tube" method on the skin of rats’ tails. It has been established that petroleum products can penetrate the intact skin and, with repeated admission, cause a general toxic effect. There were reductions bodyweights, the negative effect on the function of the kidneys and liver, changes of hematological parameters, as well as activation of the antioksidatnoy system. Repeated intragastric administration does not lead to the death of the animals testifying to the lack of accumulation capacity for petroleum products at the level of functional mortal effects, the cumulation coefficient being > 5.1. Negative impact on urinary function and hepatobiliary system, changes in hematological parameters and activation of the «lipid peroxidation – antioksidant defense» were observed.

  8. Quality control during repeated fryings

    Directory of Open Access Journals (Sweden)

    Cuesta, C.

    1998-08-01

    Full Text Available Most of the debate ¡s about how the slow or frequent turnover of fresh fat affects the deterioration, of fat used in frying. Then, the modification of different oils used in repeated fryings of potatoes without or with turnover of fresh oil, under similar frying conditions, was evaluated by two criteria: by measuring the total polar component isolated by column chromatography and by the evaluation of the specific compounds related to thermoxidative and hydrolytic alteration by High Performance Size Exclusion Chromatography (HPSEC. The results indicate that with frequent turnover of fresh oil, the critical level of 25% of polar material is rarely reached, and there are fewer problems with fat deterioration because the frying tended to increase the level of polar material and thermoxidative compounds (polymers and dimers of triglycerides and oxidized triglycerides in the fryer oil during the first fryings, followed by minor changes and a tendency to reach a near-steady state in successive fryings. However, in repeated frying of potatoes using a null turnover the alteration rate was higher being linear the relationship found between polar material or the different thermoxidative compounds and the number of fryings. On the other hand chemical reactions produced during deep-fat frying can be minimized by using proper oils. In addition the increased level of consumers awareness toward fat composition and its impact on human health could had an impact on the selection of fats for snacks and for industry. In this way monoenic fats are the most adequate from a nutritional point of view and for its oxidative stability during frying.

  9. Personal exposure control system

    International Nuclear Information System (INIS)

    Tanabe, Ken-ichi; Akashi, Michio

    1994-01-01

    Nuclear power stations are under strict radiation control. Exposure control for nuclear workers is the most important operation, and so carefully thought out measures are taken. This paper introduces Fuji Electric's personal exposure control system that meets strict exposure control and rationalizes control operations. The system has a merit that it can provide required information in an optimum form using the interconnection of a super minicomputer and exposure control facilities and realizes sophisticated exposure control operations. (author)

  10. Increasing Positive Perceptions of Counseling: The Importance of Repeated Exposures

    Science.gov (United States)

    Kaplan, Scott A.; Vogel, David L.; Gentile, Douglas A.; Wade, Nathaniel G.

    2012-01-01

    This study assesses the effectiveness of repeated exposures to a video intervention based on the Elaboration Likelihood Model. The video was designed to increase help-seeking attitudes and perceptions of peer norms and to decrease the stigma associated with seeking counseling. Participants were 290 undergraduates who were randomly assigned to a…

  11. Repeated exposure to conditioned fear stress increases anxiety and delays sleep recovery following exposure to an acute traumatic stressor

    Directory of Open Access Journals (Sweden)

    Benjamin N Greenwood

    2014-10-01

    Full Text Available Repeated stressor exposure can sensitize physiological responses to novel stressors and facilitate the development of stress-related psychiatric disorders including anxiety. Disruptions in diurnal rhythms of sleep-wake behavior accompany stress-related psychiatric disorders and could contribute to their development. Complex stressors that include fear-eliciting stimuli can be a component of repeated stress experienced by humans, but whether exposure to repeated fear can prime the development of anxiety and sleep disturbances is unknown. In the current study, adult male F344 rats were exposed to either control conditions or repeated contextual fear conditioning for 22 days followed by exposure to either no, mild (10, or severe (100 acute uncontrollable tail shock stress. Exposure to acute stress produced anxiety-like behavior as measured by a reduction in juvenile social exploration and exaggerated shock-elicited freezing in a novel context. Prior exposure to repeated fear enhanced anxiety-like behavior as measured by shock-elicited freezing, but did not alter social exploratory behavior. The potentiation of anxiety produced by prior repeated fear was temporary; exaggerated fear was present 1 day but not 4 days following acute stress. Interestingly, exposure to acute stress reduced REM and NREM sleep during the hours immediately following acute stress. This initial reduction in sleep was followed by robust REM rebound and diurnal rhythm flattening of sleep / wake behavior. Prior repeated fear extended the acute stress-induced REM and NREM sleep loss, impaired REM rebound, and prolonged the flattening of the diurnal rhythm of NREM sleep following acute stressor exposure. These data suggest that impaired recovery of sleep / wake behavior following acute stress could contribute to the mechanisms by which a history of prior repeated stress increases vulnerability to subsequent novel stressors and stress-related disorders.

  12. Repeated cue exposure effects on subjective and physiological indices of chocolate craving

    OpenAIRE

    Van Gucht, Dinska; Vansteenwegen, Debora; Beckers, Tom; Hermans, Dirk; Baeyens, Frank; Van den Bergh, Omer

    2008-01-01

    The aim of this study is to investigate the effects of repeated unreinforced exposure to chocolate cues in persons reporting chocolate craving. Participants in the experimental group (n=40) received 10 consecutive brief exposures to chocolate cues in each of two sessions, separated by 1-3 days. Control participants (n=18) received two exposures at the start and end of each session. Chocolate craving was measured (alternately) through subjective report and the amount of saliva secretion to cho...

  13. The effects of repeated low-dose sarin exposure

    International Nuclear Information System (INIS)

    Shih, T.-M.; Hulet, S.W.; McDonough, J.H.

    2006-01-01

    habituate to some aspects of neurobehavioral testing. Spectral analysis of EEG data suggested that repeated sarin exposure may disrupt normal sleeping patterns (i.e., lower frequency bandwidths). While these EEG changes returned to relative normalcy 6 days after the last injection in animals receiving 0.4 x LD 5 sarin, these changes were still observed in the animals that received 0.5 x LD 5 sarin. Ten to twelve days after the last sarin injection (in 0.4 x LD 5 group only), neurochemical data showed that striatal choline levels were reduced in comparison to the saline group. At this time, atropine sulfate (5 mg/kg, i.p.) challenge resulted in a transient elevation in striatal ACh levels in animals exposed to repeated 0.4 x LD 5 sarin as well as in control animals. No evidence of brain or heart pathology was found in any guinea pig that survived all 10 sarin injections

  14. Absence of bacterial resistance following repeat exposure to photodynamic therapy

    Science.gov (United States)

    Pedigo, Lisa A.; Gibbs, Aaron J.; Scott, Robert J.; Street, Cale N.

    2009-06-01

    The prevalence of antibiotic resistant bacteria necessitates exploration of alternative approaches to treat hospital and community acquired infections. The aim of this study was to determine whether bacterial pathogens develop resistance to antimicrobial photodynamic therapy (aPDT) during repeated sub-lethal challenge. Antibiotic sensitive and resistant strains of S. aureus and antibiotic sensitive E. coli were subjected to repeat PDT treatments using a methylene blue photosensitizer formulation and 670 nm illumination from a non-thermal diode laser. Parameters were adjusted such that kills were antibiotic resistance strains. Furthermore, repeated sub-lethal exposure does not induce resistance to subsequent PDT treatments. The absence of resistance formation represents a significant advantage of PDT over traditional antibiotics.

  15. Behavioral sensitization after repeated formaldehyde exposure in rats.

    Science.gov (United States)

    Sorg, B A; Hochstatter, T

    1999-01-01

    Multiple chemical sensitivity (MCS) is a phenomenon whereby individuals report increased sensitivity to chemicals in the environment, and attribute their sensitivities to prior exposure to the same or often structurally unrelated chemicals. A leading hypothesis suggests that MCS is akin to behavioral sensitization observed in rodents after repeated exposure to drugs of abuse or environmental stressors. Sensitization occurring within limbic circuitry of the central nervous system (CNS) may explain the multisymptom complaints in individuals with MCS. The present studies represent the continuing development of an animal model for MCS, the basis of which is the CNS sensitization hypothesis. Three behaviors were assessed in rats repeatedly exposed to formaldehyde (Form) inhalation. In the first series of experiments, rats were given high-dose Form exposure (11 parts per million [ppm]; 1 h/day x 7 days) or low-dose Form exposure (1 ppm; either 1 h/day x 7 days or 1 h/day x 5 days/week x 4 weeks). Within a few days after discontinuing daily Form, cocaine-induced locomotor activity was elevated after high-dose Form or 20 days of low-dose Form inhalation. Approximately 1 month later, cocaine-induced locomotor activity remained significantly elevated in the 20-day Form-exposed rats. The second experiment assessed whether prior exposure to Form (20 days, as above) would alter the ability to condition to an odor (orange oil) paired with footshock. The results suggested a tendency to increase the conditioned fear response to the odor but not the context of the footshock box, and a decreased tendency to extinguish the conditioned fear response to odor. The third experiment examined whether CNS sensitization to daily cocaine or stress would alter subsequent avoidance responding to odor (Form). Daily cocaine significantly elevated approach responses to Form, while daily stress pretreatment produced a trend in the opposite direction, producing greater avoidance of Form. Preliminary

  16. Attenuated response to repeated daily ozone exposures in asthmatic subjects

    Energy Technology Data Exchange (ETDEWEB)

    Gong, H. Jr.; Linn, W.S. [Rancho Low Amigos Medical Center, Downey, CA (United States); McManus, M.S. [Univ. of California, Los Angeles, CA (United States)

    1997-01-01

    The development of attenuated response ({open_quotes}tolerance{close_quotes}) to daily ozone (O{sub 3}) exposures in the laboratory is well established in healthy adult volunteers. However, the capability of asthmatics to develop tolerance during multiday ozone exposures in unclear. We exposed 10 adult volunteers with mild asthma to 0.4 ppm O{sub 3} in filtered air for 3 h/d on 5 consecutive d. Two similar filtered-air exposures during the preceding week served as controls. Follow-up O{sub 3} exposures were performed 4 and 7 d after the most recent consecutive exposure. All exposures were performed in an environmental chamber at 31 {degrees}C and 35% relative humidity. The subjects performed moderate exercise (mean ventilation rate of 32 l/min) for 15 min of each half-hour. Responses were measured with spirometry and symptom evaluations before and after each exposure, and a bronchial reactivity test (methacholine challenge) was conducted after each exposure. All response measurements showed clinically and statistically significant day-to-day variation. Symptom and forced-expiratory-volume-in-1-s responses were similarly large on the 1st and 2nd O{sub 3} exposure days, after which they diminished progressively, approaching filtered air response levels by the 5th consecutive O{sub 3} day. This tolerance was partially lost 4 and 7 d later. Bronchial reactivity peaked after the first O{sub 3} exposure and remained somewhat elevated after all subsequent O{sub 3} exposures, relative to its control level following filtered-air exposures. Individual responses varied widely; more severe initial responses to O{sub 3} predicted less rapid attenuation. We concluded that asthmatics can develop tolerance to frequent high-level O{sub 3} exposures in much the same manner as normal subjects, although the process may be slower and less fully effective in asthmatics. 27 refs., 3 figs., 4 tabs.

  17. Firefighting and mental health: Experiences of repeated exposure to trauma.

    Science.gov (United States)

    Jahnke, Sara A; Poston, Walker S Carlos; Haddock, Christopher K; Murphy, Beth

    2016-02-15

    Firefighters must be ready to respond to a broad range of emergencies every duty day. In the course of many of these emergencies, firefighters witness events which have the potential to induce emotional trauma, such as badly injured people, deceased children, and individuals who are highly distraught. Previous research suggests that repeated exposure to these traumas (RET) may have negative impacts on the emotional and mental health of fire service personnel. Research on the mental health of firefighters has been limited to small surveys reporting the prevalence of specific mental health problems such as depression and post-traumatic stress disorder among firefighters. Despite the likelihood that RET leads to negative outcomes in firefighters, data is lacking on how exposure impacts fire service personnel. The current study examines the experiences of firefighters related to RET. Using formative research methods, we examined the beliefs and experiences of firefighters and administrators from across the United States regarding the impact of RET on firefighter health. Study findings highlight the cumulative psychological toll of repeated exposure to traumatic events including desensitization, flashbacks, and irritability. Results of the current study suggest that RET is a significant concern for emergency responders that warrants additional research and attention. It is likely that the long term consequences of RET are closely intertwined with other mental health outcomes and general well-being of this important occupational group.

  18. Developmental differences in stress responding after repeated underwater trauma exposures in rats.

    Science.gov (United States)

    Altman, Daniel E; Simmons, Laurence P; Vuong, Chau T; Taylor, Rachel M; Sousa, Jason C; Marcsisin, Sean R; Zottig, Victor E; Moore, Nicole L T

    2018-05-01

    Adolescence is a distinct developmental period characterized by behavioral and physiological maturation. Rapid ongoing changes during neurodevelopment in particular present potential opportunities for stress to have lasting effects on longitudinal outcomes of behavioral and neuroendocrine function. While adult stress effects on outcomes during adulthood have been characterized, little is known about the lasting effects of adolescent repeated stressor exposure on outcomes during adolescence. We have previously reported different stress responses in adolescent rats relative to adult rats, including a blunted fear response outcome in adulthood in rats stressed during adolescence. The present study characterized the ontogeny of behavioral and neuroendocrine responses to eight underwater trauma (UWT) exposures in rats over a two week poststress time period during adolescence (P34) or adulthood (P83) relative to age-matched control groups that underwent eight swimming episodes without UWT. Repeated UWT exposures starting in adolescence, but not adulthood, resulted in adverse behavioral responses on the elevated plus maze 1 day post-stress. Corticosterone responses did not differ between UWT-exposed and controls for either age group at 1 day or at 7 days poststress, although there was an effect of age on corticosterone levels. We conclude that repeated UWT stress events have a lasting, negative behavioral effect on adolescent rats that is not observed in adult rats after the two-week exposure window. These results suggest that neurophysiological mechanisms underlying recovery from a repeated stressor are immature in adolescence relative to adulthood in rats.

  19. Repeated isoflurane exposure and neuroapoptosis in the midgestation fetal sheep brain.

    Science.gov (United States)

    Olutoye, Olutoyin A; Sheikh, Fariha; Zamora, Irving J; Yu, Ling; Akinkuotu, Adesola C; Adesina, Adekunle M; Olutoye, Oluyinka O

    2016-04-01

    Advances in surgery and technology have resulted in increased in-utero procedures. However, the effect of anesthesia on the fetal brain is not fully known. The inhalational anesthetic agent, isoflurane, other gamma amino butyric acid agonists (benzodiazepines, barbiturates, propofol, other inhalation anesthetics), and N-methyl D aspartate antagonists, eg, ketamine, have been shown to induce neuroapoptosis. The ovine model has been used extensively to study maternal-fetal physiologic interactions and to investigate different surgical interventions on the fetus. The purpose of this study was to determine effects of different doses and duration of isoflurane on neuroapoptosis in midgestation fetal sheep. We hypothesized that repeated anesthetic exposure and high concentrations of isoflurane would result in increased neuroapoptosis. Time-dated, pregnant sheep at 70 days gestation (term 145 days) received either isoflurane 2% × 1 hour, 4% × 3 hours, or 2% × 1 hour every other day for 3 exposures (repeated exposure group). Euthanasia occurred following anesthetic exposure and fetal brains were processed. Neuroapoptosis was detected by immunohistochemistry using anticaspase-3 antibodies. Fetuses unexposed to anesthesia served as controls. Another midgestation group with repeated 2% isoflurane exposure was examined at day 130 (long-term group) and neuronal cell density compared to age-matched controls. Representative sections of the brain were analyzed using Aperio Digital imaging (Leica Microsystems Inc, Buffalo Grove, IL). Data, reported by number of neurons per cubic millimeter of brain tissue are presented as means and SEM. Data were analyzed using the Mann-Whitney U and Kruskal-Wallis tests as appropriate. A total of 34 fetuses were studied. There was no significant difference in neuroapoptosis observed in fetuses exposed to 2% isoflurane for 1 hour or 4% isoflurane for 3 hours. Increased neuroapoptosis was observed in the frontal cortex following repeated 2

  20. Biological effects of repeated exposure of beagle dogs to relatively insoluble aerosols of 144Ce. IV

    International Nuclear Information System (INIS)

    Boecker, B.B.; Hahn, F.F.; Hanika-Rebar, C.; McClellan, R.O.; Mauderly, J.L.; Pickrell, J.A.

    1977-01-01

    This experiment is being conducted to study the behavior and long-term biological effects in Beagle dogs of 144 Ce inhaled in fused aluminosilicate particles in repeated inhalation exposures for comparison with similar data from dogs that were exposed only once to a similar aerosol. Four groups of nine dogs each were exposed once every eight weeks for two years (13 exposures) to achieve specified exposure goals. The 144 Ce-exposed dogs received increasing or relatively constant beta radiation dose rates in contrast to the steadily decreasing dose rate seen after a single inhalation exposure. Exposures in the first and second groups were planned to yield a cumulative absorbed dose to lung of approximately equal to 35,000 rads and those in the third group approximately equal to 17,000 rads within two years after the first exposure. Singly exposed dogs that had died with pulmonary tumors when this experiment was initiated had cumulative doses to death of 29,000 to 61,000 rads. All 13 exposures have been completed. One dog in the 4.5-μCi 144 Ce/kg body weight group died at 771 days after first exposure with emaciation, adrenal cortical degeneration and bone marrow aplasia. One control dog died accidentally during anesthesia. During the past year, two additional dogs have died. One dog in the repeated 2.5-μCi 144 Ce/kg body weight group died at 1256 days after the first exposure with radiation pneumonitis and pulmonary fibrosis and a control dog died at 1052 days with autoimmune hemolytic anemia. The remaining 32 dogs appear to be in good physical condition except for a persistent lymphopenia at approximately equal to 4 years after the first exposure. They are being maintained for life span observations

  1. Repeated nicotine exposure enhances reward-related learning in the rat.

    Science.gov (United States)

    Olausson, Peter; Jentsch, J David; Taylor, Jane R

    2003-07-01

    Repeated exposure to addictive drugs causes neuroadaptive changes in cortico-limbic-striatal circuits that may underlie alterations in incentive-motivational processes and reward-related learning. Such drug-induced alterations may be relevant to drug addiction because enhanced incentive motivation and increased control over behavior by drug-associated stimuli may contribute to aspects of compulsive drug-seeking and drug-taking behaviors. This study investigated the consequences of repeated nicotine treatment on the acquisition and performance of Pavlovian discriminative approach behavior, a measure of reward-related learning, in male rats. Water-restricted rats were trained to associate a compound conditioned stimulus (tone+light) with the availability of water (the unconditioned stimulus) in 15 consecutive daily sessions. In separate experiments, rats were repeatedly treated with nicotine (0.35 mg/kg, s.c.) either (1) prior to the onset of training, (2) after each daily training session was completed (ie postsession injections), or (3) received nicotine both before the onset of training as well as after each daily training session. In this study, all nicotine treatment schedules increased Pavlovian discriminative approach behavior and, thus, prior repeated exposure to nicotine, repeated postsession nicotine injections, or both, facilitated reward-related learning.

  2. Repeated Exposure to Conditioned Fear Stress Increases Anxiety and Delays Sleep Recovery Following Exposure to an Acute Traumatic Stressor

    OpenAIRE

    Greenwood, Benjamin N.; Thompson, Robert S.; Opp, Mark R.; Fleshner, Monika

    2014-01-01

    Repeated stressor exposure can sensitize physiological responses to novel stressors and facilitate the development of stress-related psychiatric disorders including anxiety. Disruptions in diurnal rhythms of sleep–wake behavior accompany stress-related psychiatric disorders and could contribute to their development. Complex stressors that include fear-eliciting stimuli can be a component of repeated stress experienced by human beings, but whether exposure to repeated fear can prime the develo...

  3. The Effects of Repeated Exposure to Graphic Fear Appeals on Cigarette Packages: A Field Experiment

    NARCIS (Netherlands)

    Dijkstra, A.; Bos, C.

    2015-01-01

    Experimental studies on the effects of graphic fear appeals on cigarette packages typically expose smokers in a single session to a fear appeal, although in practice the exposure is always repeated. The present study applied an improved study design with repeated exposure to fear appeals on

  4. The Effects of Repeated Exposure to Graphic Fear Appeals on Cigarette Packages : A Field Experiment

    NARCIS (Netherlands)

    Dijkstra, Arie; Colin, Bos,

    2015-01-01

    Experimental studies on the effects of graphic fear appeals on cigarette packages typically expose smokers in a single session to a fear appeal, although in practice the exposure is always repeated. The present study applied an improved study design with repeated exposure to fear appeals on

  5. Dealing with consumer differences in liking during repeated exposure to food; typical dynamics in rating behavior

    NARCIS (Netherlands)

    Horst, ter G.J.; Renken, R.; Nanneti, L.; Dalenberg, J.R.; Wijk, de R.A.

    2014-01-01

    Consumers show high interindividual variability in food liking during repeated exposure. To investigate consumer liking during repeated exposure, data is often interpreted on a product level by averaging results over all consumers. However, a single product may elicit inconsistent behaviors in

  6. Dealing with Consumer Differences in Liking during Repeated Exposure to Food; Typical Dynamics in Rating Behavior

    NARCIS (Netherlands)

    Dalenberg, Jelle R.; Nanetti, Luca; Renken, Remco J.; de Wijk, Rene A.; ter Horst, Gert J.

    2014-01-01

    Consumers show high interindividual variability in food liking during repeated exposure. To investigate consumer liking during repeated exposure, data is often interpreted on a product level by averaging results over all consumers. However, a single product may elicit inconsistent behaviors in

  7. Consequences of repeated ethanol exposure during early or late adolescence on conditioned taste aversions in rats

    Directory of Open Access Journals (Sweden)

    Jessica Saalfield

    2015-12-01

    Full Text Available Alcohol use is prevalent during adolescence, yet little is known about possible long-lasting consequences. Recent evidence suggests that adolescents are less sensitive than adults to ethanol's aversive effects, an insensitivity that may be retained into adulthood after repeated adolescent ethanol exposure. This study assessed whether intermittent ethanol exposure during early or late adolescence (early-AIE or late-AIE, respectively would affect ethanol conditioned taste aversions 2 days (CTA1 and >3 weeks (CTA2 post-exposure using supersaccharin and saline as conditioning stimuli (CS, respectively. Pair-housed male Sprague-Dawley rats received 4 g/kg i.g. ethanol (25% or water every 48 h from postnatal day (P 25–45 (early AIE or P45-65 (late AIE, or were left non-manipulated (NM. During conditioning, 30 min home cage access to the CS was followed by 0, 1, 1.5, 2 or 2.5 g/kg ethanol i.p., with testing 2 days later. Attenuated CTA relative to controls was seen among early and late AIE animals at both CTA1 and CTA2, an effect particularly pronounced at CTA1 after late AIE. Thus, adolescent exposure to ethanol was found to induce an insensitivity to ethanol CTA seen soon after exposure and lasting into adulthood, and evident with ethanol exposures not only early but also later in adolescence.

  8. Consequences of repeated ethanol exposure during early or late adolescence on conditioned taste aversions in rats.

    Science.gov (United States)

    Saalfield, Jessica; Spear, Linda

    2015-12-01

    Alcohol use is prevalent during adolescence, yet little is known about possible long-lasting consequences. Recent evidence suggests that adolescents are less sensitive than adults to ethanol's aversive effects, an insensitivity that may be retained into adulthood after repeated adolescent ethanol exposure. This study assessed whether intermittent ethanol exposure during early or late adolescence (early-AIE or late-AIE, respectively) would affect ethanol conditioned taste aversions 2 days (CTA1) and >3 weeks (CTA2) post-exposure using supersaccharin and saline as conditioning stimuli (CS), respectively. Pair-housed male Sprague-Dawley rats received 4g/kg i.g. ethanol (25%) or water every 48 h from postnatal day (P) 25-45 (early AIE) or P45-65 (late AIE), or were left non-manipulated (NM). During conditioning, 30 min home cage access to the CS was followed by 0, 1, 1.5, 2 or 2.5g/kg ethanol i.p., with testing 2 days later. Attenuated CTA relative to controls was seen among early and late AIE animals at both CTA1 and CTA2, an effect particularly pronounced at CTA1 after late AIE. Thus, adolescent exposure to ethanol was found to induce an insensitivity to ethanol CTA seen soon after exposure and lasting into adulthood, and evident with ethanol exposures not only early but also later in adolescence. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  9. Repeated exposure to immobilization or two different footshock intensities reveals differential adaptation of the hypothalamic-pituitary-adrenal axis.

    Science.gov (United States)

    Rabasa, Cristina; Muñoz-Abellán, Cristina; Daviu, Núria; Nadal, Roser; Armario, Antonio

    2011-05-03

    Factors involved in adaptation to repeated stress are not well-characterized. For instance, acute footshock (FS) of high intensity appears to be less severe than immobilization (IMO) in light of the speed of post-stress recovery of the hypothalamic-pituitary-adrenal (HPA) axis and other physiological variables. However, repeated exposure to IMO consistently resulted in reduction of the HPA response to the same stressor (adaptation), whereas failure to adapt has been usually reported after FS. Thus, in the present work we directly compared the activation of HPA axis and other physiological changes in response to both acute and repeated exposure to IMO and two intensities of FS (medium and high) in adult male rats. Control rats were exposed to the FS boxes but they did not receive shocks. Daily repeated exposure to IMO resulted in significant adaptation of the overall ACTH and corticosterone responses to the stressor. Such a reduction was also observed with repeated exposure to FS boxes and FS-medium, whereas repeated exposure to FS-high only resulted in a small reduction of the corticosterone response during the post-stress period. This suggests that some properties of FS-high make adaptation to it difficult. Interestingly, overall changes in food intake and body weight gain throughout the week of exposure to the stressors reveal a greater impact of IMO than FS-high, indicating that factors other than the intensity of a stressor, at least when evaluated in function of the above physiological variables, can influence HPA adaptation. Since FS exposure is likely to cause more pain than IMO, activation of nociceptive signals above a certain level may negatively affect HPA adaptation to repeated stressors. Copyright © 2011 Elsevier Inc. All rights reserved.

  10. Micronucleus induction by repeated exposure of diagnostic X-ray on oral buccal mucosa

    International Nuclear Information System (INIS)

    Lohith Tejashvi, K.; Suchetha Kumari, N.; Shetty, Shishir Ram

    2012-01-01

    Radiography is the important diagnostic tools essential for diagnosis and planning of orthodontic treatment. X-ray is ionizing radiation which showed various effects include breaking the bond of biological molecules, inducing loss of ability of cell death, increases nuclear alterations. Micronuclei - x000D - (MN) are small chromatin bodies that appear in the cytoplasm by the - x000D - condensation of acrocentric chromosomal fragments or by whole chromosomes. This - x000D - is a sensitive indicator of genetic damage. - x000D - x000D - . To evaluate micronucleus induction by repeated exposure of diagnostic X-ray on human buccal cell. Methods: 25 patients who visiting to ABSMIDS, Department of Oral medicine and Radiology for dental checkup exposed to diagnostic X-ray more than 4 times have been selected for this study. The buccal cell for analysis was collected from the cheek mucosa by means of gentle scraping of epithelial using ice-cream sticks and placed in Buffer saline. This sample was smeared on glass slide and then fixed in methanol:glacial acetic acid (3:1). Air dried and stained with Giemsa for 15-25 minutes. Then 250 cells in each slides were analyzed under microscope and frequency of micronucleus was scored (n=4). Repeated X-ray exposed cells showed micronucleus (1.25%) and nuclear alteration (2.3%) compare to the control. Repeated X-ray exposure leads to induces detectable number of micronucleus and nuclear alterations. (author)

  11. Effect of repeated benzene inhalation exposures on benzene metabolism, binding to hemoglobin, and induction of micronuclei

    International Nuclear Information System (INIS)

    Sabourin, P.J.; Sun, J.D.; MacGregor, J.T.; Wehr, C.M.; Birnbaum, L.S.; Lucier, G.; Henderson, R.F.

    1990-01-01

    Metabolism of benzene is thought to be necessary to produce the toxic effects, including carcinogenicity, associated with benzene exposure. To extrapolate from the results of rodent studies to potential health risks in man, one must know how benzene metabolism is affected by species, dose, dose rate, and repeated versus single exposures. The purpose of our studies was to determine the effect of repeated inhalation exposures on the metabolism of [14C]benzene by rodents. Benzene metabolism was assessed by characterizing and quantitating urinary metabolites, and by quantitating 14C bound to hemoglobin and micronuclei induction. F344/N rats and B6C3F1 mice were exposed, nose-only, to 600 ppm benzene or to air (control) for 6 hr/day, 5 days/week for 3 weeks. On the last day, both benzene-pretreated and control animals were exposed to 600 ppm, 14C-labeled benzene for 6 hr. Individual benzene metabolites in urine collected for 24 hr after the exposure were analyzed. There was a significant decrease in the respiratory rate of mice (but not rats) pretreated with benzene which resulted in lower levels of urinary [14C]benzene metabolites. The analyses indicated that the only effects of benzene pretreatment on the metabolite profile in rat or mouse urine were a slight shift from glucuronidation to sulfation in mice and a shift from sulfation to glucuronidation in rats. Benzene pretreatment also had no effect, in either species, on formation of [14C]benzene-derived hemoglobin adducts. Mice and rats had similar levels of hemoglobin adduct binding, despite the higher metabolism of benzene by mice. This indicates that hemoglobin adduct formation occurs with higher efficiency in rats. After 1 week of exposure to 600 ppm benzene, the frequency of micronucleated, polychromatic erythrocytes (PCEs) in mice was significantly increased

  12. Repeated restraint stress exposure during early withdrawal accelerates incubation of cue-induced cocaine craving.

    Science.gov (United States)

    Glynn, Ryan M; Rosenkranz, J Amiel; Wolf, Marina E; Caccamise, Aaron; Shroff, Freya; Smith, Alyssa B; Loweth, Jessica A

    2018-01-01

    A major challenge for treating cocaine addiction is the propensity for abstinent users to relapse. Two important triggers for relapse are cues associated with prior drug use and stressful life events. To study their interaction in promoting relapse during abstinence, we used the incubation model of craving and relapse in which cue-induced drug seeking progressively intensifies ('incubates') during withdrawal from extended-access cocaine self-administration. We tested rats for cue-induced cocaine seeking on withdrawal day (WD) 1. Rats were then subjected to repeated restraint stress or control conditions (seven sessions held between WD6 and WD14). All rats were tested again for cue-induced cocaine seeking on WD15, 1 day after the last stress or control session. Although controls showed a time-dependent increase in cue-induced cocaine seeking (incubation), rats exposed to repeated stress in early withdrawal exhibited a more robust increase in seeking behavior between WD1 and WD15. In separate stressed and control rats, equivalent cocaine seeking was observed on WD48. These results indicate that repeated stress in early withdrawal accelerates incubation of cocaine craving, although craving plateaus at the same level were observed in controls. However, 1 month after the WD48 test, rats subjected to repeated stress in early withdrawal showed enhanced cue-induced cocaine seeking following acute (24 hours) food deprivation stress. Together, these data indicate that chronic stress exposure enhances the initial rate of incubation of craving during early withdrawal, resulting in increased vulnerability to cue-induced relapse during this period, and may lead to a persistent increase in vulnerability to the relapse-promoting effects of stress. © 2016 Society for the Study of Addiction.

  13. Biological effects of repeated inhalation exposure of beagle dogs to relatively insoluble aerosols of 144Ce

    International Nuclear Information System (INIS)

    Boecker, B.B.; Hahn, F.F.; Muggenburg, B.A.; McClellan, R.O.; Mauderly, J.L.; Pickrell, J.A.

    1980-01-01

    Beagle dogs were exposed repeatedly to a relatively insoluble form of 144 Ce (in fused aluminosilicate particles) to study the deposition, retention, and long-term biological effects for comparison with data from dogs that were exposed only once to a similar aerosol. Four groups of nine dogs each were exposed once every 8 weeks for 2 years (13 exposures) to achieve specified exposure goals. These goals were: to increase the lung burden by 2.5 μCi 144 Ce/kg body weight with each exposure; to reestablish lung burdens of 9 or 4.5 μCi 144 Ce/kg body weight and to expose controls to fused aluminosilicate particles containing nonradioactive cerium. To date, 19 exposed dogs and 2 control dogs have died or were euthanized. The most prevalent findings to date have been pulmonary carcinomas (7 dogs) and hemangiosarcomas in the tracheobronchial lymph nodes (3 dogs). Observations are continuing on the surviving 8 144 Ce-exposed and 7 control dogs who are now at approximately 2500 days (6.8 years) after the first exposure

  14. Repeated inhalation exposure of Beagle dogs to aerosols of 239PuO2. XII

    International Nuclear Information System (INIS)

    Diel, J.H.; Hahn, F.F.; Muggenburg, B.A.

    1988-01-01

    Beagle dogs were exposed once or semi-annually for 10 yr by inhalation to aerosols of 239 PuO 2 to study the relative doses and effects of these two types of exposures. All exposures have been completed. Dogs exposed at high levels died predominantly of radiation pneumonitis and pulmonary fibrosis. Dogs exposed at lower levels, either once or repeatedly, are dying of a variety of causes including lung cancer. Dogs have survived up to 11 yr after their first exposure. Preliminary results suggest that single and repeated exposures cause similar health effects for equal accumulated radiation doses. (author)

  15. Neonates' responses to repeated exposure to a still face.

    Science.gov (United States)

    Nagy, Emese; Pilling, Karen; Watt, Rachel; Pal, Attila; Orvos, Hajnalka

    2017-01-01

    The main aims of the study were to examine whether human neonates' responses to communication disturbance modelled by the still-face paradigm were stable and whether their responses were affected by their previous experience with the still-face paradigm. The still face procedure, as a laboratory model of interpersonal stress, was administered repeatedly, twice, to 84 neonates (0 to 4 day olds), with a delay of an average of 1.25 day. Frame-by-frame analysis of the frequency and duration of gaze, distressed face, crying, sleeping and sucking behaviours showed that the procedure was stressful to them both times, that is, the still face effect was stable after repeated administration and newborns consistently responded to such nonverbal violation of communication. They averted their gaze, showed distress and cried more during the still-face phase in both the first and the second administration. They also showed a carry-over effect in that they continued to avert their gaze and displayed increased distress and crying in the first reunion period, but their gaze behaviour changed with experience, in the second administration. While in the first administration the babies continued averting their gaze even after the stressful still-face phase was over, this carry-over effect disappeared in the second administration, and the babies significantly increased their gaze following the still-face phase. After excluding explanations of fatigue, habituation and random effects, a self-other regulatory model is discussed as a possible explanation for this pattern.

  16. A General Model for Repeated Audit Controls Using Monotone Subsampling

    OpenAIRE

    Raats, V.M.; van der Genugten, B.B.; Moors, J.J.A.

    2002-01-01

    In categorical repeated audit controls, fallible auditors classify sample elements in order to estimate the population fraction of elements in certain categories.To take possible misclassifications into account, subsequent checks are performed with a decreasing number of observations.In this paper a model is presented for a general repeated audit control system, where k subsequent auditors classify elements into r categories.Two different sub-sampling procedures will be discussed, named 'stra...

  17. Neonates’ responses to repeated exposure to a still face

    Science.gov (United States)

    Pilling, Karen; Watt, Rachel; Pal, Attila; Orvos, Hajnalka

    2017-01-01

    Aim The main aims of the study were to examine whether human neonates’ responses to communication disturbance modelled by the still-face paradigm were stable and whether their responses were affected by their previous experience with the still-face paradigm. Methods The still face procedure, as a laboratory model of interpersonal stress, was administered repeatedly, twice, to 84 neonates (0 to 4 day olds), with a delay of an average of 1.25 day. Results Frame-by-frame analysis of the frequency and duration of gaze, distressed face, crying, sleeping and sucking behaviours showed that the procedure was stressful to them both times, that is, the still face effect was stable after repeated administration and newborns consistently responded to such nonverbal violation of communication. They averted their gaze, showed distress and cried more during the still-face phase in both the first and the second administration. They also showed a carry-over effect in that they continued to avert their gaze and displayed increased distress and crying in the first reunion period, but their gaze behaviour changed with experience, in the second administration. While in the first administration the babies continued averting their gaze even after the stressful still-face phase was over, this carry-over effect disappeared in the second administration, and the babies significantly increased their gaze following the still-face phase. Conclusion After excluding explanations of fatigue, habituation and random effects, a self-other regulatory model is discussed as a possible explanation for this pattern. PMID:28771555

  18. Tumorigenic responses from single or repeated inhalation exposures to relatively insoluble aerosols of Ce-144

    International Nuclear Information System (INIS)

    Boecker, B.B.; Hahn, F.F.; Mauderly, J.L.; McClellan, R.O.

    1980-01-01

    Human occupational or environmental inhalation exposures may involve repeated or chronic exposures, but most laboratory studies of inhaled radionuclides have involved single exposures. This study was designed to compare the biological effects of repeated inhalation exposures of dogs to a relatively insoluble form of 144 Ce with existing data for singly-exposed dogs that had the same cumulative dose to the lungs two years after exposure. To date, the biological effects observed in these repeatedly-exposed dogs have been substantially different from those seen in singly-exposed dogs, particularly during the first 5 years after the initial exposure. Although pulmonary hemangiosarcoma was the prominent biological effect seen in singly-exposed dogs between 2 and 4 years after exposure, no lung tumors were seen during the 5 years after the first of the repeated exposures. This response plus other clinical observations are discussed in relation to the patterns of dose rate and cumulative dose for the different exposure conditions. (H.K.)

  19. Radiation camera exposure control

    International Nuclear Information System (INIS)

    Martone, R.J.; Yarsawich, M.; Wolczek, W.

    1976-01-01

    A system and method for governing the exposure of an image generated by a radiation camera to an image sensing camera is disclosed. The exposure is terminated in response to the accumulation of a predetermined quantity of radiation, defining a radiation density, occurring in a predetermined area. An index is produced which represents the value of that quantity of radiation whose accumulation causes the exposure termination. The value of the predetermined radiation quantity represented by the index is sensed so that the radiation camera image intensity can be calibrated to compensate for changes in exposure amounts due to desired variations in radiation density of the exposure, to maintain the detectability of the image by the image sensing camera notwithstanding such variations. Provision is also made for calibrating the image intensity in accordance with the sensitivity of the image sensing camera, and for locating the index for maintaining its detectability and causing the proper centering of the radiation camera image

  20. Adaptive Changes in Sensorimotor Coordination and Motion Sickness Following Repeated Exposures to Virtual Environments

    Science.gov (United States)

    Harm, D. L.; Taylor, L. C.; Bloomberg, J. J.

    2007-01-01

    Virtual environments offer unique training opportunities, particularly for training astronauts and preadapting them to the novel sensory conditions of microgravity. Two unresolved human factors issues in virtual reality (VR) systems are: 1) potential "cybersickness", and 2) maladaptive sensorimotor performance following exposure to VR systems. Interestingly, these aftereffects are often quite similar to adaptive sensorimotor responses observed in astronauts during and/or following space flight. Initial interpretation of novel sensory information may be inappropriate and result in perceptual errors. Active exploratory behavior in a new environment, with resulting feedback and the formation of new associations between sensory inputs and response outputs, promotes appropriate perception and motor control in the new environment. Thus, people adapt to consistent, sustained alterations of sensory input such as those produced by microgravity, unilateral labyrinthectomy and experimentally produced stimulus rearrangements. The purpose of this research was to compare disturbances in sensorimotor coordination produced by dome and head-mounted virtual environment displays and to examine the effects of exposure duration, and repeated exposures to VR systems. The first study examined disturbances in balance control, and the second study examined disturbances in eye-head-hand (EHH) and eye-head coordination.

  1. The Effects of Repeated Low-Dose Sarin Exposure

    Science.gov (United States)

    2005-08-01

    support the idea that there is a triphasic NT model for onset and progression of seizures and subsequent brain damage upon acute exposure to OP ChE...An ACh microbore column (1x530 mm ID, 10 µm UniJet, BAS #MF-8904) coupled with AChE/choline oxidase immobilized enzyme reactor (BAS # MF-8903) was...peroxidase to the electrode for the reduction of hydrogen peroxide that was generated from the immobilized enzyme reactor . The detector was set at (-)1.0

  2. The effects of repeated low-level blast exposure on hearing in marines

    Directory of Open Access Journals (Sweden)

    Lina R Kubli

    2017-01-01

    Full Text Available Background: The study evaluates a group of Military Service Members specialized in blast explosive training called “Breachers” who are routinely exposed to multiple low-level blasts while teaching breaching at the U.S. Marine Corps in Quantico Virginia. The objective of this study was to determine if there are any acute or long-term auditory changes due to repeated low-level blast exposures used in training. The performance of the instructor group “Breachers” was compared to a control group, “Engineers”. Methods: A total of 11 Breachers and four engineers were evaluated in the study. The participants received comprehensive auditory tests, including pure-tone testing, speech-in-noise (SIN measures, and central auditory behavioral and objective tests using early and late (P300 auditory evoked potentials over a period of 17 months. They also received shorter assessments immediately following the blast-exposure onsite at Quantico. Results: No acute or longitudinal effects were identified. However, there were some interesting baseline effects found in both groups. Contrary to the expected, the onsite hearing thresholds and distortion product otoacoustic emissions were slightly better at a few frequencies immediately after blast-exposure than measurements obtained with the same equipment weeks to months after each blast-exposure. Conclusions: To date, the current study is the most comprehensive study that evaluates the long-term effects of blast-exposure on hearing. Despite extensive testing to assess changes, the findings of this study suggest that the levels of current exposures used in this military training environment do not seem to have an obvious deleterious effect on hearing.

  3. Repeated cue exposure effects on subjective and physiological indices of chocolate craving

    NARCIS (Netherlands)

    van Gucht, D.; Vansteenwegen, D.; Beckers, T.; Hermans, D.; Baeyens, F.; Van den Bergh, O.

    2008-01-01

    The aim of this study is to investigate the effects of repeated unreinforced exposure to chocolate cues in persons reporting chocolate craving. Participants in the experimental group (n ¼ 40) received 10 consecutive brief exposures to chocolate cues in each of two sessions, separated by 1-3 days.

  4. Repeated Acute Oral Exposure to Cannabis sativa Impaired ...

    African Journals Online (AJOL)

    olayemitoyin

    Saline was administered to the control rats, cannabis (20 mg/kg) to the experimental group ... Keywords: Anxiety, Cannabis toxicity, Cortex, Memory, Hippocampus. ©Physiological Society ..... cognitive and psycho-motor behaviours. It has also.

  5. Glucometabolic effects of single and repeated exposure to forced-swimming stressor in Sprague-Dawley rats.

    Science.gov (United States)

    Morakinyo, Ayodele Olufemi; Iranloye, Bolanle Olubusola; Ogunsola, Oluseyi Abimbola

    2018-04-01

    We aimed to evaluate the effects of a single (acute) and repeated (chronic) exposure to forced-swimming stressor on glucose tolerance, insulin sensitivity, lipid profile and glycogen content in male rats. Thirty adult male Sprague-Dawley rats (12 weeks old) were divided randomly into five groups: control group, single exposure (SE) to forced-swim stressor, repeated exposure to forced-swim stressor for 7 days (RE7), 14 days (RE14) and 28 days (RE28). Glucose tolerance test and Homeostatic Model Assessment-Insulin Resistance (HOMA-IR) were undertaken on fasting rats to obtain glucose and insulin profiles. ELISA was performed to assess plasma insulin and corticosterone levels. Total cholesterol, triglyceride, high- and low-density lipoproteins, hepatic and skeletal glycogen content were also determined. Repeated exposure to stressor induced glucose intolerance and insulin resistance in the experimental rats. Results showed that all RE groups exhibited a significantly higher area under the curve compared with others (p=0.0001); similarly, HOMA-IR increased (p=0.0001) in all RE groups compared with control. Prolonged exposure to stressor significantly increased the plasma insulin and corticosterone levels but decreased the glycogen content in the liver and skeletal muscle when compared with the control group. Additionally, chronic stressor significantly increased the total cholesterol and triglyceride levels, however, acute stressor produced significantly elevated high-density lipoproteins level. In conclusion, repeated exposure to forced-swimming stressor induced glucose intolerance and insulin resistance in rats by disrupting the insulin sensitivity as well as heightening the glycogenolysis in the liver and skeletal muscle. Acute stressor was unable to cause glucose intolerance and insulin resistance but it appears that may have a positive effect on the lipid metabolism.

  6. The Role of Repeated Exposure to Multimodal Input in Incidental Acquisition of Foreign Language Vocabulary.

    Science.gov (United States)

    Bisson, Marie-Josée; van Heuven, Walter J B; Conklin, Kathy; Tunney, Richard J

    2014-12-01

    Prior research has reported incidental vocabulary acquisition with complete beginners in a foreign language (FL), within 8 exposures to auditory and written FL word forms presented with a picture depicting their meaning. However, important questions remain about whether acquisition occurs with fewer exposures to FL words in a multimodal situation and whether there is a repeated exposure effect. Here we report a study where the number of exposures to FL words in an incidental learning phase varied between 2, 4, 6, and 8 exposures. Following the incidental learning phase, participants completed an explicit learning task where they learned to recognize written translation equivalents of auditory FL word forms, half of which had occurred in the incidental learning phase. The results showed that participants performed better on the words they had previously been exposed to, and that this incidental learning effect occurred from as little as 2 exposures to the multimodal stimuli. In addition, repeated exposure to the stimuli was found to have a larger impact on learning during the first few exposures and decrease thereafter, suggesting that the effects of repeated exposure on vocabulary acquisition are not necessarily constant.

  7. Analysis of real-time mixture cytotoxicity data following repeated exposure using BK/TD models

    International Nuclear Information System (INIS)

    Teng, S.; Tebby, C.; Barcellini-Couget, S.; De Sousa, G.; Brochot, C.; Rahmani, R.; Pery, A.R.R.

    2016-01-01

    Cosmetic products generally consist of multiple ingredients. Thus, cosmetic risk assessment has to deal with mixture toxicity on a long-term scale which means it has to be assessed in the context of repeated exposure. Given that animal testing has been banned for cosmetics risk assessment, in vitro assays allowing long-term repeated exposure and adapted for in vitro – in vivo extrapolation need to be developed. However, most in vitro tests only assess short-term effects and consider static endpoints which hinder extrapolation to realistic human exposure scenarios where concentration in target organs is varies over time. Thanks to impedance metrics, real-time cell viability monitoring for repeated exposure has become possible. We recently constructed biokinetic/toxicodynamic models (BK/TD) to analyze such data (Teng et al., 2015) for three hepatotoxic cosmetic ingredients: coumarin, isoeugenol and benzophenone-2. In the present study, we aim to apply these models to analyze the dynamics of mixture impedance data using the concepts of concentration addition and independent action. Metabolic interactions between the mixture components were investigated, characterized and implemented in the models, as they impacted the actual cellular exposure. Indeed, cellular metabolism following mixture exposure induced a quick disappearance of the compounds from the exposure system. We showed that isoeugenol substantially decreased the metabolism of benzophenone-2, reducing the disappearance of this compound and enhancing its in vitro toxicity. Apart from this metabolic interaction, no mixtures showed any interaction, and all binary mixtures were successfully modeled by at least one model based on exposure to the individual compounds. - Highlights: • We could predict cell response over repeated exposure to mixtures of cosmetics. • Compounds acted independently on the cells. • Metabolic interactions impacted exposure concentrations to the compounds.

  8. Analysis of real-time mixture cytotoxicity data following repeated exposure using BK/TD models

    Energy Technology Data Exchange (ETDEWEB)

    Teng, S.; Tebby, C. [Models for Toxicology and Ecotoxicology Unit, INERIS, Parc Technologique Alata, BP 2, 60550 Verneuil-en-Halatte (France); Barcellini-Couget, S. [ODESIA Neosciences, Sophia Antipolis, 400 route des chappes, 06903 Sophia Antipolis (France); De Sousa, G. [INRA, ToxAlim, 400 route des Chappes, BP, 167 06903 Sophia Antipolis, Cedex (France); Brochot, C. [Models for Toxicology and Ecotoxicology Unit, INERIS, Parc Technologique Alata, BP 2, 60550 Verneuil-en-Halatte (France); Rahmani, R. [INRA, ToxAlim, 400 route des Chappes, BP, 167 06903 Sophia Antipolis, Cedex (France); Pery, A.R.R., E-mail: alexandre.pery@agroparistech.fr [AgroParisTech, UMR 1402 INRA-AgroParisTech Ecosys, 78850 Thiverval Grignon (France); INRA, UMR 1402 INRA-AgroParisTech Ecosys, 78850 Thiverval Grignon (France)

    2016-08-15

    Cosmetic products generally consist of multiple ingredients. Thus, cosmetic risk assessment has to deal with mixture toxicity on a long-term scale which means it has to be assessed in the context of repeated exposure. Given that animal testing has been banned for cosmetics risk assessment, in vitro assays allowing long-term repeated exposure and adapted for in vitro – in vivo extrapolation need to be developed. However, most in vitro tests only assess short-term effects and consider static endpoints which hinder extrapolation to realistic human exposure scenarios where concentration in target organs is varies over time. Thanks to impedance metrics, real-time cell viability monitoring for repeated exposure has become possible. We recently constructed biokinetic/toxicodynamic models (BK/TD) to analyze such data (Teng et al., 2015) for three hepatotoxic cosmetic ingredients: coumarin, isoeugenol and benzophenone-2. In the present study, we aim to apply these models to analyze the dynamics of mixture impedance data using the concepts of concentration addition and independent action. Metabolic interactions between the mixture components were investigated, characterized and implemented in the models, as they impacted the actual cellular exposure. Indeed, cellular metabolism following mixture exposure induced a quick disappearance of the compounds from the exposure system. We showed that isoeugenol substantially decreased the metabolism of benzophenone-2, reducing the disappearance of this compound and enhancing its in vitro toxicity. Apart from this metabolic interaction, no mixtures showed any interaction, and all binary mixtures were successfully modeled by at least one model based on exposure to the individual compounds. - Highlights: • We could predict cell response over repeated exposure to mixtures of cosmetics. • Compounds acted independently on the cells. • Metabolic interactions impacted exposure concentrations to the compounds.

  9. Analysis of Dextromethorphan and Dextrorphan in Skeletal Remains Following Differential Microclimate Exposure: Comparison of Acute vs. Repeated Drug Exposure.

    Science.gov (United States)

    Morrison, Lucas M; Unger, Kirk A; Watterson, James H

    2017-07-01

    Analysis of dextromethorphan (DXM) and its metabolite dextrorphan (DXT) in skeletal remains of rats following acute (ACU, 75 mg/kg, IP, n = 10) or three repeated (REP, 25 mg/kg, IP, n = 10, 40-min interval) doses of DXM is described. Following dosing and euthanasia, rats decomposed outdoors to skeleton in two different microclimate environments (n = 5 ACU and n = 5 REP at each site): Site A (shaded forest microenvironment) and Site B (rocky substrate exposed to direct sunlight, 600 m from Site A). Two drug-free rats at each site served as negative controls. Skeletal elements (vertebrae, ribs, pelvic girdles, femora, tibiae, skulls and scapulae) were recovered, pulverized and underwent methanolic microwave assisted extraction (MAE). Extracts were analyzed by GC-MS following clean-up by solid-phase extraction (SPE). Drug levels, expressed as mass-normalized response ratios and the ratios of DXT and DXM levels (RRDXT/RRDXM) were compared between drug exposures, microclimate sites, and across skeletal elements. DXM levels differed significantly (P < 0.05) between corresponding bone elements across exposure groups (5/7-site A; 4/7-site B), but no significant differences in DXT levels were observed between corresponding elements. RRDXT/RRDXM differed significantly (P < 0.05) between corresponding bone elements across exposure groups (6/7-site A; 5/7-site B). No significant differences were observed in levels of DXM, DXT or RRDXT/RRDXM between corresponding elements from either group between sites. When data from all bone elements was pooled, levels of DXM and RRDXT/RRDXM differed significantly between exposure groups at each site, while those of DXT did not. For both exposure groups, comparison of pooled data between sites showed no significant differences in levels of DXM, DXT or RRDXT/RRDXM. Different decomposition microclimates did not impede the discrimination of DXM exposure patterns from the analyses of DXM, DXT and RRDXT/RRDXM in bone samples. © The Author 2017

  10. Effects of repeated exposure to white noise on central cholinergic activity in the rat.

    Science.gov (United States)

    Lai, H

    1988-03-01

    Acute (45 min) exposure to noise has been shown to decrease sodium-dependent high-affinity choline uptake activity in the frontal cortex and hippocampus of the rat. In the present experiment, the effects of repeated noise exposure on choline uptake in these two brain regions were studied. Rats were exposed to 100-dB white noise in ten 45-min sessions. Tolerance developed to the effects of noise on choline uptake. In addition, the effects were found to be classically conditionable to cues in the exposure environment. These data may have important implications in understanding the health hazard of noise exposure in both the public and occupational environments.

  11. The hidden price of repeated traumatic exposure: Different cognitive deficits in different first-responders

    Directory of Open Access Journals (Sweden)

    Einat eLevy-Gigi

    2014-08-01

    Full Text Available Studies on first responders who are repeatedly exposed to traumatic events report low levels of PTSD symptoms and diagnosis. However, neuroimaging and behavioral studies show that traumatic exposure is associated with brain and cognitive dysfunctions. Taking together it may suggest that traumatic exposure have a price, which is not sufficiently defined by the standard PTSD measures. In a recent study we revealed that similar to individuals with PTSD, non-PTSD highly exposed firefighters display a selective impairment in hippocampal related functions. In the current study we aimed to test whether different first responders display a similar impairment. We concentrated on unique populations of active duty firefighters and criminal scene-investigators (CSI police, who are frequently exposed to similar levels and types of traumatic events, and compared them to civilian matched-controls with no history of trauma-exposure. We used a hippocampal dependent cue-context reversal paradigm, which separately evaluates reversal of negative and positive outcomes of cue and context related information. We predicted and found that all participants were equally able to acquire and retain stimulus-outcome associations. However, there were significant differences in reversal learning between the groups. Performance among firefighters replicated our prior findings; they struggled to learn that a previously negative context is later associated with a positive outcome. CSI police on the other hand showed a selective impairment in reversing the outcome of a negative cue. Hence after learning that a specific cue is associated with a negative outcome, they could not learn that later it is associated with a positive outcome. Performance in both groups did not correlate with levels of PTSD, anxiety, depression or behavioral inhibition symptoms. The results provide further evidence of the hidden price of traumatic exposure, suggesting that this price may differ as a

  12. Primary blast survival and injury risk assessment for repeated blast exposures.

    Science.gov (United States)

    Panzer, Matthew B; Bass, Cameron R Dale; Rafaels, Karin A; Shridharani, Jay; Capehart, Bruce P

    2012-02-01

    The widespread use of explosives by modern insurgents and terrorists has increased the potential frequency of blast exposure in soldiers and civilians. This growing threat highlights the importance of understanding and evaluating blast injury risk and the increase of injury risk from exposure to repeated blast effects. Data from more than 3,250 large animal experiments were collected from studies focusing on the effects of blast exposure. The current study uses 2,349 experiments from the data collection for analysis of the primary blast injury and survival risk for both long- and short-duration blasts, including the effects from repeated exposures. A piecewise linear logistic regression was performed on the data to develop survival and injury risk assessment curves. New injury risk assessment curves uniting long- and short-duration blasts were developed for incident and reflected pressure measures and were used to evaluate the risk of injury based on blast over pressure, positive-phase duration, and the number of repeated exposures. The risk assessments were derived for three levels of injury severity: nonauditory, pulmonary, and fatality. The analysis showed a marked initial decrease in injury tolerance with each subsequent blast exposure. This effect decreases with increasing number of blast exposures. The new injury risk functions showed good agreement with the existing experimental data and provided a simplified model for primary blast injury risk. This model can be used to predict blast injury or fatality risk for single exposure and repeated exposure cases and has application in modern combat scenarios or in setting occupational health limits. .Copyright © 2012 by Lippincott Williams & Wilkins

  13. Control of external radiation exposure

    International Nuclear Information System (INIS)

    Abd Nasir Ibrahim; Azali Muhammad; Ab Razak Hamzah; Abd Aziz Mohamed; Mohammad Pauzi Ismail

    2004-01-01

    The following subjects are discussed - Control of external radiation exposure: working time, working distance, shielding: Total Linear Attenuation Coefficient, Half-Value Layer (HVL), Tenth-Value Layer (TVL); Build-up Factor

  14. A General Model for Repeated Audit Controls Using Monotone Subsampling

    NARCIS (Netherlands)

    Raats, V.M.; van der Genugten, B.B.; Moors, J.J.A.

    2002-01-01

    In categorical repeated audit controls, fallible auditors classify sample elements in order to estimate the population fraction of elements in certain categories.To take possible misclassifications into account, subsequent checks are performed with a decreasing number of observations.In this paper a

  15. Repeated exposure to media violence is associated with diminished response in an inhibitory frontolimbic network.

    Directory of Open Access Journals (Sweden)

    Christopher R Kelly

    Full Text Available BACKGROUND: Media depictions of violence, although often claimed to induce viewer aggression, have not been shown to affect the cortical networks that regulate behavior. METHODOLOGY/PRINCIPAL FINDINGS: Using functional magnetic resonance imaging (fMRI, we found that repeated exposure to violent media, but not to other equally arousing media, led to both diminished response in right lateral orbitofrontal cortex (right ltOFC and a decrease in right ltOFC-amygdala interaction. Reduced function in this network has been previously associated with decreased control over a variety of behaviors, including reactive aggression. Indeed, we found reduced right ltOFC responses to be characteristic of those subjects that reported greater tendencies toward reactive aggression. Furthermore, the violence-induced reduction in right ltOFC response coincided with increased throughput to behavior planning regions. CONCLUSIONS: These novel findings establish that even short-term exposure to violent media can result in diminished responsiveness of a network associated with behaviors such as reactive aggression.

  16. A re-examination of the mere exposure effect: The influence of repeated exposure on recognition, familiarity, and liking.

    Science.gov (United States)

    Montoya, R Matthew; Horton, Robert S; Vevea, Jack L; Citkowicz, Martyna; Lauber, Elissa A

    2017-05-01

    To evaluate the veracity of models of the mere exposure effect and to understand the processes that moderate the effect, we conducted a meta-analysis of the influence of repeated exposure on liking, familiarity, recognition, among other evaluations. We estimated parameters from 268 curve estimates drawn from 81 articles and revealed that the mere exposure effect was characterized by a positive slope and negative quadratic effect consistent with an inverted-U shaped curve. In fact, such curves were associated with (a) all visual, but not auditory stimuli; (b) exposure durations shorter than 10 s and longer than 1 min; (c) both homogeneous and heterogeneous presentation types; and (d) ratings that were taken after all stimuli were presented. We conclude that existing models for the mere exposure effect do not adequately account for the findings, and we provide a framework to help guide future research. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  17. Consumer acceptance of salt-reduced 'soy sauce' foods over rapidly repeated exposure

    NARCIS (Netherlands)

    Kremer, S.; Shimojo, R.; Holthuysen, N.T.E.; Köster, E.P.; Mojet, J.

    2013-01-01

    The stability of the liking for salt reduced products was tested in a rapidly repeated exposure study using soup and bread (with ham). Salt was partially replaced by naturally brewed soy sauce. First, 44 consumers performed 5 two-alternative forced choice tests to establish the exchange rate (ER) at

  18. College in the Media: The Relationship between Repeated Exposure and College Expectations

    Science.gov (United States)

    Nuñez, Roland

    2018-01-01

    Media consumption can influence viewer perceptions and attitudes. Recent research on media's effect on college students has failed to address gender differences. Using Mere Repeated Exposure Theory (traditionally used in marketing research), this study aims to answer three research questions regarding college media consumption and college…

  19. Sweet and sour preferences in young children and adults: role of repeated exposure

    NARCIS (Netherlands)

    Liem, D.G.; Graaf, de C.

    2004-01-01

    The authors investigated the influence of repeated exposure to orangeades with added sucrose and different concentrations of citric acid, on the taste preferences of 6- to-11-year-old children and young adults. During an intervention study of 8 days, 59 children (9.2±0.9 years) and 46 young adults

  20. Information technology-based approaches to reducing repeat drug exposure in patients with known drug allergies.

    Science.gov (United States)

    Cresswell, Kathrin M; Sheikh, Aziz

    2008-05-01

    There is increasing interest internationally in ways of reducing the high disease burden resulting from errors in medicine management. Repeat exposure to drugs to which patients have a known allergy has been a repeatedly identified error, often with disastrous consequences. Drug allergies are immunologically mediated reactions that are characterized by specificity and recurrence on reexposure. These repeat reactions should therefore be preventable. We argue that there is insufficient attention being paid to studying and implementing system-based approaches to reducing the risk of such accidental reexposure. Drawing on recent and ongoing research, we discuss a number of information technology-based interventions that can be used to reduce the risk of recurrent exposure. Proven to be effective in this respect are interventions that provide real-time clinical decision support; also promising are interventions aiming to enhance patient recognition, such as bar coding, radiofrequency identification, and biometric technologies.

  1. Impact of repeated daily exposure to intermittent hypoxia and mild sustained hypercapnia on apnea severity.

    Science.gov (United States)

    Yokhana, Sanar S; Gerst, David G; Lee, Dorothy S; Badr, M Safwan; Qureshi, Tabarak; Mateika, Jason H

    2012-02-01

    We examined whether exposure to intermittent hypoxia (IH) during wakefulness impacted on the apnea/hypopnea index (AHI) during sleep in individuals with sleep apnea. Participants were exposed to twelve 4-min episodes of hypoxia in the presence of sustained mild hypercapnia each day for 10 days. A control group was exposed to sustained mild hypercapnia for a similar duration. The intermittent hypoxia protocol was completed in the evening on day 1 and 10 and was followed by a sleep study. During all sleep studies, the change in esophageal pressure (ΔPes) from the beginning to the end of an apnea and the tidal volume immediately following apneic events were used to measure respiratory drive. Following exposure to IH on day 1 and 10, the AHI increased above baseline measures (day 1: 1.95 ± 0.42 fraction of baseline, P ≤ 0.01, vs. day 10: 1.53 ± 0.24 fraction of baseline, P < 0.06). The indexes were correlated to the hypoxic ventilatory response (HVR) measured during the IH protocol but were not correlated to the magnitude of ventilatory long-term facilitation (vLTF). Likewise, ΔPes and tidal volume measures were greater on day 1 and 10 compared with baseline (ΔPes: -8.37 ± 0.84 vs. -5.90 ± 1.30 cmH(2)0, P ≤ 0.04; tidal volume: 1,193.36 ± 101.85 vs. 1,015.14 ± 119.83 ml, P ≤ 0.01). This was not the case in the control group. Interestingly, the AHI on day 10 (0.78 ± 0.13 fraction of baseline, P ≤ 0.01) was significantly less than measures obtained during baseline and day 1 in the mild hypercapnia control group. We conclude that enhancement of the HVR initiated by exposure to IH may lead to increases in the AHI during sleep and that initiation of vLTF did not appear to impact on breathing stability. Lastly, our results suggest that repeated daily exposure to mild sustained hypercapnia may lead to a decrease in breathing events.

  2. Effects of moxifloxacin exposure on the conjunctival flora and antibiotic resistance profile following repeated intravitreal injections

    Directory of Open Access Journals (Sweden)

    Mustafa Ataş

    2014-10-01

    Full Text Available AIM:To evaluate the effects of moxifloxacin exposure on the conjunctival flora and antibiotic resistance profile following repeated intravitreal injections.METHODS:Seventy-two eyes of 36 patients [36 eyes in control group, 36 eyes in intravitreal injection (IVI group] were enrolled in the study. All the eyes had at least one IVI and had diabetic macular edema (DME or age-related macular degeneration (ARMD. Moxifloxacin was prescribed to all the patients four times a day for five days following injection. Conjunctival cultures were obtained from the lower fornix via standardized technique with every possible effort made to minimize contamination from the lids, lashes, or skin. Before the application of any ophthalmic medication, conjunctival cultures were obtained from both eyes using sterile cotton culture. An automated microbiology system was used to identify the growing bacteria and determine antibiotic sensitivity. RESULTS:The bacterial cultures were isolated from 72 eyes of 36 patients, sixteen of whom patients (44.4% were male and twenty (55.6% were female. Average age was 68.4±9.0 (range 50-86. The average number of injections before taking cultures was 3.1+1.0. Forty-eight (66.7% of 72 eyes had at least one significant organism. There was no bacterial growth in 8 (20.5% of IVI eyes and in 16 (44.4% of control eyes (P=0.03. Of the bacteria isolated from culture, 53.8% of coagulase negative staphylococci (CoNS in IVI eyes and 47.2% CoNS in control eyes. This difference between IVI eyes and control eyes about bacteria isolated from culture was not statistically significant (P=0.2. Eleven of 25 bacteria (44.0% isolated from IVI eyes and 11 (57.9% of 19 bacteria isolated from control eyes were resistant to oxacillin. The difference in frequency of moxifloxacine resistance between two groups was not statistically significant (12.0% in IVI eyes and 21.1% in control eyes (P=0.44. There were no cases of resistance to vancomycin, teicoplanin and

  3. Analysis of real-time mixture cytotoxicity data following repeated exposure using BK/TD models.

    Science.gov (United States)

    Teng, S; Tebby, C; Barcellini-Couget, S; De Sousa, G; Brochot, C; Rahmani, R; Pery, A R R

    2016-08-15

    Cosmetic products generally consist of multiple ingredients. Thus, cosmetic risk assessment has to deal with mixture toxicity on a long-term scale which means it has to be assessed in the context of repeated exposure. Given that animal testing has been banned for cosmetics risk assessment, in vitro assays allowing long-term repeated exposure and adapted for in vitro - in vivo extrapolation need to be developed. However, most in vitro tests only assess short-term effects and consider static endpoints which hinder extrapolation to realistic human exposure scenarios where concentration in target organs is varies over time. Thanks to impedance metrics, real-time cell viability monitoring for repeated exposure has become possible. We recently constructed biokinetic/toxicodynamic models (BK/TD) to analyze such data (Teng et al., 2015) for three hepatotoxic cosmetic ingredients: coumarin, isoeugenol and benzophenone-2. In the present study, we aim to apply these models to analyze the dynamics of mixture impedance data using the concepts of concentration addition and independent action. Metabolic interactions between the mixture components were investigated, characterized and implemented in the models, as they impacted the actual cellular exposure. Indeed, cellular metabolism following mixture exposure induced a quick disappearance of the compounds from the exposure system. We showed that isoeugenol substantially decreased the metabolism of benzophenone-2, reducing the disappearance of this compound and enhancing its in vitro toxicity. Apart from this metabolic interaction, no mixtures showed any interaction, and all binary mixtures were successfully modeled by at least one model based on exposure to the individual compounds. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Damage of rat liver tissue caused by repeated and sustained +Gz exposure and the mechanism thereof

    Directory of Open Access Journals (Sweden)

    Wen-bing LI

    2014-03-01

    Full Text Available Objective  To explore the mechanisms of positive acceleration (+Gz on the damage of rat liver tissue and the effect of +Gz on the expression of JNK/c-Jun in liver cells. Methods  Twenty four male Wistar rats were randomly divided into 4 groups (n=6: control, +2Gz, +6Gz and +10Gz group. With prone position, the rats in control group were fixed to the turning arm of centrifuge with head towards the axis for 5 minutes. The fixation method in +2Gz, +6Gz and +10Gz group was the same as in the control group. The increase rate of acceleration was 1G/s with a peak-time of 3 minutes, and each +Gz exposure repeated 5 times with an interval of 30 minutes. HE staining was used to observe the morphological changes of liver tissue, fluorescence real-time quantitative PCR to detect the expression of hepatic c-Jun mRNA, and Western blotting to detect the hepatic protein expression of p-c-Jun, c-Jun, p-JNK and JNK. Plasma aspartate aminotransferase (AST and alanine aminotransferase (ALT were determined. Results  The levels of serum ALT and AST increased significantly in +6Gz and, especially, the +10Gz group than in control group and +2Gz group (P<0.05. The same situation also existed in the increase of c-Jun mRNA expression (P<0.05. Hepatic c-jun and p-c-Jun (c-Jun activated form protein expression increased with the increase of G value. Compared with control group, no change was found in JNK protein expression in the other three groups, but the expression of p-JNK (activated form of JNK increased in +6Gz and +10Gz groups (P<0.05. HE staining showed the disorganized liver cells with irregular shapes, the unclear cell gap and the vacuolar changes in +6Gz and +10Gz groups. Conclusions  Repeated and sustained +Gz may cause enhanced expression of c-Jun/ p-c-Jun and p-JNK in hepatic cells. JNK/c-Jun signaling pathway may play an important role in the process of hepatic stress injury. DOI: 10.11855/j.issn.0577-7402.2014.03.15

  5. Personal exposure control using TLD

    International Nuclear Information System (INIS)

    Ishiguro, Hideharu; Takeda, Shinso

    1979-01-01

    In the Tokai Works of the Power Reactor and Nuclear Fuel Development Corporation (PNC), for personal exposure control, the switching from film badges to TLD badges (and also finger-ring type local dosimeters) was made in fiscal 1974. The facilities involved are a fuel reprocessing plant, a PuO 2 -UO 2 mixed fuel production facility, and a centrifugal uranium enrichment development facility. The types of radiation concerned are various, such as γ(x), β and n. The situation of personal exposure control with TLD and the dose evaluation methods for respective radiations are explained. The number of personnel subject to exposure control, including transient people, is about 2500 - 3000 per three months. The TLD badges used are a special PNC type with TLDs to measure separately γ(x), β and n. With casings made of ABS resin, the external dimensions are 76 mm x 46 mm. (J.P.N.)

  6. Adaptive Changes In Postural Equilibrium And Motion Sickness Following Repeated Exposures To Virtual Environments

    Science.gov (United States)

    Harm, D. L.; Taylor, L. C.

    2006-01-01

    Virtual environments offer unique training opportunities, particularly for training astronauts and preadapting them to the novel sensory conditions of microgravity. Two unresolved human factors issues in virtual reality (VR) systems are: 1) potential "cybersickness", and 2) maladaptive sensorimotor performance following exposure to VR systems. Interestingly, these aftereffects are often quite similar to adaptive sensorimotor responses observed in astronauts during and/or following space flight. Changes in the environmental sensory stimulus conditions and the way we interact with the new stimuli may result in motion sickness, and perceptual, spatial orientation and sensorimotor disturbances. Initial interpretation of novel sensory information may be inappropriate and result in perceptual errors. Active exploratory behavior in a new environment, with resulting feedback and the formation of new associations between sensory inputs and response outputs, promotes appropriate perception and motor control in the new environment. Thus, people adapt to consistent, sustained alterations of sensory input such as those produced by microgravity, unilateral labyrinthectomy and experimentally produced stimulus rearrangements. Adaptation is revealed by aftereffects including perceptual disturbances and sensorimotor control disturbances. The purpose of the current study was to compare disturbances in postural control produced by dome and head-mounted virtual environment displays, and to examine the effects of exposure duration, and repeated exposures to VR systems. Forty-one subjects (21 men, 20 women) participated in the study with an age range of 21-49 years old. One training session was completed in order to achieve stable performance on the posture and VR tasks before participating in the experimental sessions. Three experimental sessions were performed each separated by one day. The subjects performed a navigation and pick and place task in either a dome or head-mounted display

  7. Effect of Repeated Food Morsel Splitting on Jaw Muscle Control

    DEFF Research Database (Denmark)

    A, Kumar; Svensson, Krister G; Baad-Hansen, Lene

    2014-01-01

    Mastication is a complex motor task often initiated by splitting of the food morsel between the anterior teeth. Training of complex motor tasks has consistently been shown to trigger neuroplastic changes in corticomotor control and optimization of muscle function. It is not known if training...... and repeated food morsel splitting lead to changes in jaw muscle function. Objective: To investigate if repeated splitting of food morsels in participants with natural dentition changes the force and jaw muscle electromyographic (EMG) activity. Methods: Twenty healthy volunteers (mean age = 26.2 ± 3.9 years......) participated in a single one-hour session divided into six series. Each series consisted of ten trials of a standardized behavioral task (total of 60 trials). The behavioral task was to hold and split a food morsel (8 mm, 180 mg placebo tablet) placed on a bite force transducer with the anterior teeth...

  8. The root of the problem: increasing root vegetable intake in preschool children by repeated exposure and flavour flavour learning.

    Science.gov (United States)

    Ahern, Sara M; Caton, Samantha J; Blundell, Pam; Hetherington, Marion M

    2014-09-01

    Children's vegetable consumption falls below current recommendations, highlighting the need to identify strategies that can successfully promote intake. The current study aimed to investigate the effectiveness of flavour-flavour learning as one such strategy for increasing vegetable intake in preschool children. Children (N = 29) aged 15 to 56 months were recruited through participating nurseries. Each received a minimum of six and maximium eight exposures to a root vegetable puree with added apple puree (flavour-flavour learning) alternating with six to eight exposures to another with nothing added (repeated exposure). A third puree acted as a control. Pre- and post-intervention intake measures of the three purees with nothing added were taken to assess change in intake. Follow-up measures took place 1 month (n = 28) and 6 months (n = 10) post-intervention. Intake increased significantly from pre- to post-intervention for all purees (~36 g), with no effect of condition. Magnitude of change was smaller in the control condition. Analysis of follow-up data showed that intake remained significantly higher than baseline 1 month (p exposure increases intake of a novel vegetable in young children. Results also suggest that mere exposure (to the food, the experimenters, the procedure) can generalise to other, similar vegetables but the addition of a familiar flavour confers no added advantage above mere exposure. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. Impact of repeated exposure on toxicity of perchloroethylene in Swiss Webster mice

    International Nuclear Information System (INIS)

    Philip, Binu K.; Mumtaz, Moiz M.; Latendresse, John R.; Mehendale, Harihara M.

    2007-01-01

    The aim was to study the subchronic toxicity of perchloroethylene (Perc) by measuring injury and repair in liver and kidney in relation to disposition of Perc and its major metabolites. Male SW mice (25-29 g) were given three dose levels of Perc (150, 500, and 1000 mg/kg day) via aqueous gavage for 30 days. Tissue injury was measured during the dosing regimen (0, 1, 7, 14, and 30 days) and over a time course of 24-96 h after the last dose (30 days). Perc produced significant liver injury (ALT) after single day exposure to all three doses. Liver injury was mild to moderate and regressed following repeated exposure for 30 days. Subchronic Perc exposure induced neither kidney injury nor dysfunction during the entire time course as evidenced by normal renal histology and BUN. TCA was the major metabolite detected in blood, liver, and kidney. Traces of DCA were also detected in blood at initial time points after single day exposure. With single day exposure, metabolism of Perc to TCA was saturated with all three doses. AUC/dose ratio for TCA was significantly decreased with a concomitant increase in AUC/dose of Perc levels in liver and kidney after 30 days as compared to 1 day exposures, indicating inhibition of metabolism upon repeated exposure to Perc. Hepatic CYP2E1 expression and activity were unchanged indicating that CYP2E1 is not the critical enzyme inhibited. Hepatic CYP4A expression, measured as a marker of peroxisome proliferation was increased transiently only on day 7 with the high dose, but was unchanged at later time points. Liver tissue repair peaked at 7 days, with all three doses and was sustained after medium and high dose exposure for 14 days. These data indicate that subchronic Perc exposure via aqueous gavage does not induce nephrotoxicity and sustained hepatotoxicity suggesting adaptive hepatic repair mechanisms. Enzymes other than CYP2E1, involved in the metabolism of Perc may play a critical role in the metabolism of Perc upon subchronic exposure

  10. Effects of repeated exposure to either vegetables or fruits on infant's vegetable and fruit acceptance at the beginning of weaning

    NARCIS (Netherlands)

    Barends, C.; Vries, de J.; Mojet, J.; Graaf, de C.

    2013-01-01

    This study investigated the effects of repeated exposure to either vegetables or fruits on an infant's vegetable and fruit acceptance during the first 18 days of weaning. We hypothesized that repeated exposure to a type of vegetable or fruit, would increase its intake. Furthermore, we expected that

  11. A model of human nasal epithelial cells adapted for direct and repeated exposure to airborne pollutants.

    Science.gov (United States)

    Bardet, Gaëlle; Achard, Sophie; Loret, Thomas; Desauziers, Valérie; Momas, Isabelle; Seta, Nathalie

    2014-08-17

    Airway epithelium lining the nasal cavity plays a pivotal role in respiratory tract defense and protection mechanisms. Air pollution induces alterations linked to airway diseases such as asthma. Only very few in vitro studies to date have succeeded in reproducing physiological conditions relevant to cellular type and chronic atmospheric pollution exposure. We therefore, set up an in vitro model of human Airway Epithelial Cells of Nasal origin (hAECN) close to real human cell functionality, specifically adapted to study the biological effects of exposure to indoor gaseous pollution at the environmental level. hAECN were exposed under air-liquid interface, one, two, or three-times at 24 h intervals for 1 h, to air or formaldehyde (200 μg/m(3)), an indoor air gaseous pollutant. All experiments were ended at day 4, when both cellular viability and cytokine production were assessed. Optimal adherence and confluence of cells were obtained 96 h after cell seeding onto collagen IV-precoated insert. Direct and repeated exposure to formaldehyde did not produce any cellular damage or IL-6 production change, although weak lower IL-8 production was observed only after the third exposure. Our model is significantly better than previous ones due to cell type and the repeated exposure protocol. Copyright © 2014. Published by Elsevier Ireland Ltd.

  12. Long-term health outcomes after exposure to repeated concussion in elite level: rugby union players.

    Science.gov (United States)

    McMillan, T M; McSkimming, P; Wainman-Lefley, J; Maclean, L M; Hay, J; McConnachie, A; Stewart, W

    2017-06-01

    There is continuing concern about effects of concussion in athletes, including risk of the neurodegenerative disease chronic traumatic encephalopathy. However, information on long-term health and wellbeing in former athletes is limited. Outcome after exposure to repeated brain injury was investigated in 52 retired male Scottish international rugby players (RIRP) and 29 male controls who were similar in age and social deprivation. Assessment included history of playing rugby and traumatic brain injury, general and mental health, life stress, concussion symptoms, cognitive function, disability and markers of chronic stress (allostatic load). The estimated number of concussions in RIRP averaged 14 (median=7; IQR 5-40). Performance was poorer in RIRP than controls on a test of verbal learning (p=0.022) and of fine co-ordination of the dominant hand (p=0.038) and not significantly different on other cognitive tests (p>0.05). There were no significant associations between number of concussions and performance on cognitive tests. Other than a higher incidence of cardiovascular disease in controls, no group differences were detected in general or mental health or estimates of allostatic load. In RIRP, persisting symptoms attributed to concussion were more common if reporting more than nine concussions (p=0.028), although these symptoms were not perceived to affect social or work functioning. Despite a high number of concussions in RIRP, differences in mental health, social or work functioning were not found late after injury. Subtle group differences were detected on two cognitive tests, the cause of which is uncertain. Prospective group comparison studies on representative cohorts are required. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  13. Eye lens radiation exposure and repeated head CT scans: A problem to keep in mind

    International Nuclear Information System (INIS)

    Michel, Morgane; Jacob, Sophie; Roger, Gilles; Pelosse, Béatrice; Laurier, Dominique; Le Pointe, Hubert Ducou; Bernier, Marie-Odile

    2012-01-01

    Objectives: The deterministic character of radiation-induced cataract is being called into question, raising the possibility of a risk in patients, especially children, exposed to ionizing radiation in case of repeated head CT-scans. This study aims to estimate the eye lens doses of a pediatric population exposed to repeated head CTs and to assess the feasibility of an epidemiological study. Methods: Children treated for a cholesteatoma, who had had at least one CT-scan of the middle ear before their tenth birthday, were included. Radiation exposure has been assessed from medical records and telephone interviews. Results: Out of the 39 subjects contacted, 32 accepted to participate. A total of 76 CT-scans were retrieved from medical records. At the time of the interview (mean age: 16 years), the mean number of CT per child was 3. Cumulative mean effective and eye lens doses were 1.7 mSv and 168 mGy, respectively. Conclusion: A relatively high lens radiation dose was observed in children exposed to repeated CT-scans. Due to that exposure and despite the difficulties met when trying to reach patients’ families, a large scale epidemiological study should be performed in order to assess the risk of radiation-induced cataracts associated with repeated head CT.

  14. Perturbations in different forms of cost/benefit decision making induced by repeated amphetamine exposure.

    Science.gov (United States)

    Floresco, Stan B; Whelan, Jennifer M

    2009-08-01

    Psychostimulant abuse has been linked to impairments in cost-benefit decision making. We assessed the effects of repeated amphetamine (AMPH) treatment in rodents on two distinct forms of decision making. Separate groups of rats were trained for 26 days on either a probabilistic (risk) or effort-discounting task, each consisting of four discrete blocks of ten choice trials. One lever always delivered a smaller reward (one or two pellets), whereas another lever delivered a four-pellet reward. For risk-discounting, the probability of receiving the larger reward decreased across trial blocks (100-12.5%), whereas on the effort task, four pellets could be obtained after a ratio of presses that increased across blocks (2-20). After training, rats received 15 saline or AMPH injections (escalating from 1 to 5 mg/kg) and were then retested during acute and long-term withdrawal. Repeated AMPH administration increased risky choice 2-3 weeks after drug exposure, whereas these treatments did not alter effort-based decision making in a separate group of animals. However, prior AMPH exposure sensitized the effects of acute AMPH on both forms of decision making, whereby lower doses were effective at inducing "risky" and "lazy" patterns of choice. Repeated AMPH exposure leads to relatively long-lasting increases in risky choice, as well as sensitization to the effects of acute AMPH on different forms of cost/benefit decision making. These findings suggest that maladaptive decision-making processes exhibited by psychostimulant abusers may be caused in part by repeated drug exposure.

  15. Effects of single and repeated exposure to biocidal active substances on the barrier function of the skin in vitro.

    Science.gov (United States)

    Buist, Harrie E; van de Sandt, Johannes J M; van Burgsteden, Johan A; de Heer, Cees

    2005-10-01

    The dermal route of exposure is important in worker exposure to biocidal products. Many biocidal active substances which are used on a daily basis may decrease the barrier function of the skin to a larger extent than current risk assessment practice addresses, due to possible skin effects of repeated exposure. The influence of repeated and single exposure to representative biocidal active substances on the skin barrier was investigated in vitro. The biocidal active substances selected were alkyldimethylbenzylammonium chloride (ADBAC), boric acid, deltamethrin, dimethyldidecylammonium chloride (DDAC), formaldehyde, permethrin, piperonyl butoxide, sodium bromide, and tebuconazole. Of these nine compounds, only the quaternary ammonium chlorides ADBAC and DDAC had a clear and consistent influence on skin permeability of the marker compounds tritiated water and [(14)C]propoxur. For these compounds, repeated exposure increased skin permeability more than single exposure. At high concentrations the difference between single and repeated exposure was quantitatively significant: repeated exposure to 300 mg/L ADBAC increased skin permeability two to threefold in comparison to single exposure. Therefore, single and repeated exposure to specific biocidal products may significantly increase skin permeability, especially when used undiluted.

  16. Radiation dose exposure in patients affected by lymphoma undergoing repeat CT examinations: how to manage the radiation dose variability.

    Science.gov (United States)

    Paolicchi, Fabio; Bastiani, Luca; Guido, Davide; Dore, Antonio; Aringhieri, Giacomo; Caramella, Davide

    2018-03-01

    To assess the variability of radiation dose exposure in patients affected by lymphoma undergoing repeat CT (computed tomography) examinations and to evaluate the influence of different scan parameters on the overall radiation dose. A series of 34 patients (12 men and 22 women with a median age of 34.4 years) with lymphoma, after the initial staging CT underwent repeat follow-up CT examinations. For each patient and each repeat examination, age, sex, use of AEC system (Automated Exposure Control, i.e. current modulation), scan length, kV value, number of acquired scans (i.e. number of phases), abdominal size diameter and dose length product (DLP) were recorded. The radiation dose of just one venous phase was singled out from the DLP of the entire examination. All scan data were retrieved by our PACS (Picture Archiving and Communication System) by means of a dose monitoring software. Among the variables we considered, no significant difference of radiation dose was observed among patients of different ages nor concerning tube voltage. On the contrary the dose delivered to the patients varied depending on sex, scan length and usage of AEC. No significant difference was observed depending on the behaviour of technologists, while radiologists' choices had indirectly an impact on the radiation dose due to the different number of scans requested by each of them. Our results demonstrate that patients affected by lymphoma who undergo repeat whole body CT scanning may receive unnecessary overexposure. We quantified and analyzed the most relevant variables in order to provide a useful tool to manage properly CT dose variability, estimating the amount of additional radiation dose for every single significant variable. Additional scans, incorrect scan length and incorrect usage of AEC system are the most relevant cause of patient radiation exposure.

  17. Enhancing consumer liking of low salt tomato soup over repeated exposure by herb and spice seasonings.

    Science.gov (United States)

    Ghawi, Sameer Khalil; Rowland, Ian; Methven, Lisa

    2014-10-01

    There is strong evidence for the link between high dietary sodium and increased risk of cardiovascular disease which drives the need to reduce salt content in foods. In this study, herb and spice blends were used to enhance consumer acceptability of a low salt tomato soup (0.26% w/w). Subjects (n = 148) scored their liking of tomato soup samples over 5 consecutive days. The first and last days were pre-and post-exposure visits where all participants rated three tomato soup samples; standard, low salt and low salt with added herbs and spices. The middle 3 days were the repeated exposure phase where participants were divided into three balanced groups; consuming the standard soup, the low salt soup, or the low salt soup with added herbs and spices. Reducing salt in the tomato soup led to a significant decline in consumer acceptability, and incorporating herbs and spices did not lead to an immediate enhancement in liking. However, inclusion of herbs and spices enhanced the perception of the salty taste of the low salt soup to the same level as the standard. Repeated exposure to the herbs and spice-modified soup led to a significant increase in the overall liking and liking of flavour, texture and aftertaste of the soup, whereas no changes in liking were observed for the standard and low salt tomato soups over repeated exposure. Moreover, a positive trend in increasing the post-exposure liking of the herbs and spices soup was observed. The findings suggest that the use of herbs and spices is a useful approach to reduce salt content in foods; however, herbs and spices should be chosen carefully to complement the food as large contrasts in flavour can polarise consumer liking. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

  18. Plasmid P1 replication: negative control by repeated DNA sequences.

    OpenAIRE

    Chattoraj, D; Cordes, K; Abeles, A

    1984-01-01

    The incompatibility locus, incA, of the unit-copy plasmid P1 is contained within a fragment that is essentially a set of nine 19-base-pair repeats. One or more copies of the fragment destabilizes the plasmid when present in trans. Here we show that extra copies of incA interfere with plasmid DNA replication and that a deletion of most of incA increases plasmid copy number. Thus, incA is not essential for replication but is required for its control. When cloned in a high-copy-number vector, pi...

  19. Aberrant approach-avoidance conflict resolution following repeated cocaine pre-exposure.

    Science.gov (United States)

    Nguyen, David; Schumacher, Anett; Erb, Suzanne; Ito, Rutsuko

    2015-10-01

    Addiction is characterized by persistence to seek drug reinforcement despite negative consequences. Drug-induced aberrations in approach and avoidance processing likely facilitate the sustenance of addiction pathology. Currently, the effects of repeated drug exposure on the resolution of conflicting approach and avoidance motivational signals have yet to be thoroughly investigated. The present study sought to investigate the effects of cocaine pre-exposure on conflict resolution using novel approach-avoidance paradigms. We used a novel mixed-valence conditioning paradigm to condition cocaine-pre-exposed rats to associate visuo-tactile cues with either the delivery of sucrose reward or shock punishment in the arms in which the cues were presented. Following training, exploration of an arm containing a superimposition of the cues was assessed as a measure of conflict resolution behavior. We also used a mixed-valence runway paradigm wherein cocaine-pre-exposed rats traversed an alleyway toward a goal compartment to receive a pairing of sucrose reward and shock punishment. Latency to enter the goal compartment across trials was taken as a measure of motivational conflict. Our results reveal that cocaine pre-exposure attenuated learning for the aversive cue association in our conditioning paradigm and enhanced preference for mixed-valence stimuli in both paradigms. Repeated cocaine pre-exposure allows appetitive approach motivations to gain greater influence over behavioral output in the context of motivational conflict, due to aberrant positive and negative incentive motivational processing.

  20. Repeated exposures to blue light-activated eosin Y enhance inactivation of E. faecalis biofilms, in vitro.

    Science.gov (United States)

    Marinic, Karlo; Manoil, Daniel; Filieri, Anna; Wataha, John C; Schrenzel, Jacques; Lange, Norbert; Bouillaguet, Serge

    2015-09-01

    In dentistry, antibacterial photodynamic therapy (a-PDT) has shown promising results for inactivating bacterial biofilms causing carious, endodontic and periodontal diseases. In the current study, we assessed the ability of eosin Y exposed to 3 irradiation protocols at inactivating Enterococcus faecalis biofilms, in vitro. E. faecalis biofilms formed on hydroxyapatite disks were incubated with eosin Y (10-80μM), then activated with blue light using different irradiation protocols. Biofilms exposed to continuous exposure were incubated for 40min before being light-activated for 960 s. For the intermittent exposure, biofilms were exposed 4 times to the light/photosensitizer combination (960 s total) without renewing the photosensitizer. For repeated a-PDT, the same light dose was delivered in a series of 4 irradiation periods separated by dark periods; fresh photosensitizer was added between each light irradiation. After treatment, bacteria were immediately labeled with LIVE/DEAD BacLight Bacterial Viability kit and viability was assessed by flow cytometry (FCM). Results were statistically analyzed using one-way ANOVA and Tukey multiple comparison intervals (α=0.05). The viability of E. faecalis biofilms exposed to 10μM eosin Y, was significantly reduced compared to controls (light only-eosin Y only). After a second exposure to blue light-activated eosin Y, viability significantly decreased from 58% to 12% whereas 6.5% of the bacterial biofilm remained live after a third exposure (p<0.05). Only 3.5% of the bacterial population survived after the fourth exposure. The results of this study indicate that blue light-activated eosin Y can photoinactivate E. faecalis biofilms grown on hydroxyapatite disks. Also, repeated exposures to blue light-activated eosin Y were shown to significantly improve efficacy. Further studies seem warranted to optimize the antibacterial activity of blue light-activated eosin Y on major oral pathogens. Copyright © 2015 Elsevier B.V. All

  1. Repeated exposures to roadside particulate matter extracts suppresses pulmonary defense mechanisms, resulting in lipid and protein oxidative damage

    International Nuclear Information System (INIS)

    Pardo, Michal; Porat, Ziv; Rudich, Assaf; Schauer, James J.; Rudich, Yinon

    2016-01-01

    Exposure to particulate matter (PM) pollution in cities and urban canyons can be harmful to the exposed population. However, the underlying mechanisms that lead to health effects are not yet elucidated. It is postulated that exposure to repeated, small, environmentally relevant concentrations can affect lung homeostasis. This study examines the impact of repeated exposures to urban PM on mouse lungs with focus on inflammatory and oxidative stress parameters. Aqueous extracts from collected urban PM were administered to mice by 5 repeated intra-tracheal instillations (IT). Multiple exposures, led to an increase in cytokine levels in both bronchoalveolar lavage fluid and in the blood serum, indicating a systemic reaction. Lung mRNA levels of antioxidant/phase II detoxifying enzymes decreased by exposure to the PM extract, but not when metals were removed by chelation. Finally, disruption of lung tissue oxidant-inflammatory/defense balance was evidenced by increased levels of lipid and protein oxidation. Unlike response to a single IT exposure to the same dose and source of extract, multiple exposures result in lung oxidative damage and a systemic inflammatory reaction. These could be attributed to compromised capacity to activate the protective Nrf2 tissue defense system. It is suggested that water-soluble metals present in urban PM, potentially from break and tire wear, may constitute major drivers of the pulmonary and systemic responses to multiple exposure to urban PM. - Highlights: • Repeated exposure to urban PM cause systemic inflammation and oxidative damage to lung tissue lipids and proteins. • Repeated exposure to these PM extracts decreased transcription of Nrf2 protective genes. • Single as opposed to repeated exposure, induced confined lung response accompanied by activated defense mechanisms. • Metals, potentially from break and tire wear, drive the pulmonary response with exposure to urban PM. - Repeated exposures to urban PM water extracts

  2. Repeated exposure of the developing rat brain to magnetic resonance imaging did not affect neurogenesis, cell death or memory function

    International Nuclear Information System (INIS)

    Zhu, Changlian; Gao, Jianfeng; Li, Qian; Huang, Zhiheng; Zhang, Yu; Li, Hongfu; Kuhn, Hans-Georg; Blomgren, Klas

    2011-01-01

    Research highlights: → The effect of MRI on the developing brain is a matter of debate. → Repeated exposure to MRI did not affect neurogenesis. → Memory function was not affected by repeated MRI during development. → Neither late gestation nor young postnatal brains were affected by MRI. → Repeated MRI did not cause cell death in the neurogenic region of the hippocampus. -- Abstract: The effect of magnetic fields on the brain is a matter of debate. The objective of this study was to investigate whether repeated exposure to strong magnetic fields, such as during magnetic resonance imaging (MRI), could elicit changes in the developing rat brain. Embryonic day 15 (E15) and postnatal day 14 (P14) rats were exposed to MRI using a 7.05 T MR system. The animals were anesthetized and exposed for 35 min per day for 4 successive days. Control animals were anesthetized but no MRI was performed. Body temperature was maintained at 37 o C. BrdU was injected after each session (50 mg/kg). One month later, cell proliferation, neurogenesis and astrogenesis in the dentate gyrus were evaluated, revealing no effects of MRI, neither in the E15, nor in the P14 group. DNA damage in the dentate gyrus in the P14 group was evaluated on P18, 1 day after the last session, using TUNEL staining. There was no difference in the number of TUNEL-positive cells after MRI compared with controls, neither in mature neurons, nor in newborn progenitors (BrdU/TUNEL double-labeled cells). Novel object recognition was performed to assess memory function 1 month after MRI. There was no difference in the recognition index observed after MRI compared with the control rats, neither for the E15, nor for the P14 group. In conclusion, repeated exposure to MRI did not appear to affect neurogenesis, cell death or memory function in rats, neither in late gestation (E15-E18) nor in young postnatal (P14-P17) rats.

  3. Repeated low-dose exposures to sarin, soman, or VX affect acoustic startle in guinea pigs.

    Science.gov (United States)

    Smith, C D; Lee, R B; Moran, A V; Sipos, M L

    2016-01-01

    Chemical warfare nerve agents (CWNAs) are known to cause behavioral abnormalities in cases of human exposures and in animal models. The behavioral consequences of single exposures to CWNAs that cause observable toxic signs are particularly well characterized in animals; however, less is known regarding repeated smaller exposures that may or may not cause observable toxic signs. In the current study, guinea pigs were exposed to fractions (0.1, 0.2, or 0.4) of a medial lethal dose (LD50) of sarin, soman, or VX for two weeks. On each exposure day, and for a post-exposure period, acoustic startle response (ASR) was measured in each animal. Although relatively few studies use guinea pigs to measure behavior, this species is ideal for CWNA-related experiments because their levels of carboxylesterases closely mimic those of humans, unlike rats or mice. Results showed that the 0.4 LD50 doses of soman and VX transiently increased peak startle amplitude by the second week of injections, with amplitude returning to baseline by the second week post-exposure. Sarin also increased peak startle amplitude independent of week. Latencies to peak startle and PPI were affected by agent exposure but not consistently among the three agents. Most of the changes in startle responses returned to baseline following the cessation of exposures. These data suggest that doses of CWNAs not known to produce observable toxic signs in guinea pigs can affect behavior in the ASR paradigm. Further, these deficits are transient and usually return to baseline shortly after the end of a two-week exposure period. Published by Elsevier Inc.

  4. Dose budget for exposure control

    International Nuclear Information System (INIS)

    Nair, P.S.

    1999-01-01

    Dose budget is an important management tool to effectively control the collective dose incurred in a nuclear facility. The budget represents a set of yardsticks or guidelines for use in controlling the internal activities, involving radiation exposure in the organisation. The management, through budget can evaluate the radiation protection performance at every level of the organisation where a number of independent functional groups work on routine and non-routine jobs. The discrepancy between the plan and the actual performance is high lighted through the budgets. The organisation may have to change the course of its operation in a particular area or revise its plan with due focus on appropriate protective measures. (author)

  5. Dealing with consumer differences in liking during repeated exposure to food; typical dynamics in rating behavior.

    Science.gov (United States)

    Dalenberg, Jelle R; Nanetti, Luca; Renken, Remco J; de Wijk, René A; Ter Horst, Gert J

    2014-01-01

    Consumers show high interindividual variability in food liking during repeated exposure. To investigate consumer liking during repeated exposure, data is often interpreted on a product level by averaging results over all consumers. However, a single product may elicit inconsistent behaviors in consumers; averaging will mix and hide possible subgroups of consumer behaviors, leading to a misinterpretation of the results. To deal with the variability in consumer liking, we propose to use clustering on data from consumer-product combinations to investigate the nature of the behavioral differences within the complete dataset. The resulting behavioral clusters can then be used to describe product acceptance. To test this approach we used two independent data sets in which young adults were repeatedly exposed to drinks and snacks, respectively. We found that five typical consumer behaviors existed in both datasets. These behaviors differed both in the average level of liking as well as its temporal dynamics. By investigating the distribution of a single product across typical consumer behaviors, we provide more precise insight in how consumers divide in subgroups based on their product liking (i.e. product modality). This work shows that taking into account and using interindividual differences can unveil information about product acceptance that would otherwise be ignored.

  6. Evaluation of Pulmonary and Systemic Toxicity of Oil Dispersant (COREXIT EC9500A(®)) Following Acute Repeated Inhalation Exposure.

    Science.gov (United States)

    Roberts, Jenny R; Anderson, Stacey E; Kan, Hong; Krajnak, Kristine; Thompson, Janet A; Kenyon, Allison; Goldsmith, William T; McKinney, Walter; Frazer, David G; Jackson, Mark; Fedan, Jeffrey S

    2014-01-01

    Oil spill cleanup workers come into contact with numerous potentially hazardous chemicals derived from the oil spills, as well as chemicals applied for mitigation of the spill, including oil dispersants. In response to the Deepwater Horizon Macondo well oil spill in the Gulf of Mexico in 2010, a record volume of the oil dispersant, COREXIT EC9500A, was delivered via aerial applications, raising concern regarding potential health effects that may result from pulmonary exposure to the dispersant. The current study examined the effects on pulmonary functions, cardiovascular functions, and systemic immune responses in rats to acute repeated inhalation exposure of COREXIT EC9500A at 25 mg/m(3), five hours per day, over nine work days, or filtered air (control). At one and seven days following the last exposure, a battery of parameters was measured to evaluate lung function, injury, and inflammation; cardiovascular function; peripheral vascular responses; and systemic immune responses. No significant alterations in airway reactivity were observed at one or seven days after exposure either in baseline values or following methacholine (MCh) inhalation challenge. Although there was a trend for an increase in lung neutrophils and phagocyte oxidant production at one-day post exposure, there were no significant differences in parameters of lung inflammation. In addition, increased blood monocytes and neutrophils, and decreased lymphocyte numbers at one-day post exposure also did not differ significantly from air controls, and no alterations in splenocyte populations, or serum or spleen immunoglobulin M (IgM) to antigen were observed. There were no significant differences in peripheral vascular responsiveness to vasoconstrictor and vasodilator agonists or in blood pressure (BP) responses to these agents; however, the baseline heart rate (HR) and HR responses to isoproterenol (ISO) were significantly elevated at one-day post exposure, with resolution by day 7. In summary, acute

  7. Evaluation of Pulmonary and Systemic Toxicity of Oil Dispersant (COREXIT EC9500A following Acute Repeated Inhalation Exposure

    Directory of Open Access Journals (Sweden)

    Jenny R. Roberts

    2014-01-01

    Full Text Available Introduction Oil spill cleanup workers come into contact with numerous potentially hazardous chemicals derived from the oil spills, as well as chemicals applied for mitigation of the spill, including oil dispersants. In response to the Deepwater Horizon Macondo well oil spill in the Gulf of Mexico in 2010, a record volume of the oil dispersant, COREXIT EC9500A, was delivered via aerial applications, raising concern regarding potential health effects that may result from pulmonary exposure to the dispersant. Methods The current study examined the effects on pulmonary functions, cardiovascular functions, and systemic immune responses in rats to acute repeated inhalation exposure of COREXIT EC9500A at 25 mg/m 3 , five hours per day, over nine work days, or filtered air (control. At one and seven days following the last exposure, a battery of parameters was measured to evaluate lung function, injury, and inflammation; cardiovascular function; peripheral vascular responses; and systemic immune responses. Results No significant alterations in airway reactivity were observed at one or seven days after exposure either in baseline values or following metha-choline (MCh inhalation challenge. Although there was a trend for an increase in lung neutrophils and phagocyte oxidant production at one-day post exposure, there were no significant differences in parameters of lung inflammation. In addition, increased blood monocytes and neutrophils, and decreased lymphocyte numbers at one-day post exposure also did not differ significantly from air controls, and no alterations in splenocyte populations, or serum or spleen immunoglobulin M (IgM to antigen were observed. There were no significant differences in peripheral vascular responsiveness to vasoconstrictor and vasodilator agonists or in blood pressure (BP responses to these agents; however, the baseline heart rate (HR and HR responses to isoproterenol (ISO were significantly elevated at one-day post exposure

  8. The effects of multiple UV exposures on HIV-LTR (long terminal repeat) expression

    International Nuclear Information System (INIS)

    Schreck, S.; Milton, J.; Panozzo, J.; Libertin, C.R.; Woloschak, G.E.; Loyola Univ., Maywood, IL

    1995-01-01

    Previous studies have shown that cellular stress agents such as UV radiation induce transcription from the long terminal repeat (LTR) of the human immunodeficiency virus (HIV). Using HeLa cells stably transfected with the HIV-LTR sequence, which transcriptionally drives the chloramphenicol acetyl transferase (CAT) reporter gene, we examined the effects of multiple exposures to UVC (254 nm) on HIV-LTR-CAT expression. Low doses (≤ 5 J m -2 ) had no effect on CAT expression, but up to 29-fold induction was observed with 10 J m -2 when cells were harvested 48 h after completion of the exposure. Little difference was noted in induction levels when cells were exposed to one 25 J m -2 dose, viable cells were harvested at 24 h, 48 h or 72 h, and cell lysates were assayed for CAT expression. Two sequential 12.5 J m -2 exposures, given 24 h apart, resulted in an additive effect on CAT expression; these two exposures produced CAT activity equivalent to that induced following a single 25 J m -2 dose. Our data suggest that HIV-LTR requires a specific threshold UV dose in order to elicit induction; a maximal induction dose is also evident; exposures higher than this maximal dose contribute no more to HIV-LTR induction in viable cells. (author)

  9. Repeated allergen exposure reduce early phase airway response and leukotriene release despite upregulation of 5-lipoxygenase pathways

    Directory of Open Access Journals (Sweden)

    Cui Zhi-Hua

    2012-03-01

    Full Text Available Abstract Background Allergen induced early phase airway response and airway plasma exudation are predominantly mediated by inflammatory mast cell mediators including histamine, cysteinyl leukotrienes (cysLTs and thromboxane A2 (TXA2. The aim of the present study was to evaluate whether repeated allergen exposure affects early phase airway response to allergen challenge. Methods A trimellitic anhydride (TMA sensitized guinea pig model was used to investigate the effects of low dose repeated allergen exposure on cholinergic airway responsiveness, early phase airway response and plasma exudation, as well as local airway production of mast cell derived cysteinyl leukotrienes and thromboxane B2 (TXB2 after allergen challenge. Results Repeated low dose allergen exposure increased cholinergic airway responsiveness. In contrast, early phase airway response and plasma exudation in response to a high-dose allergen challenge were strongly attenuated after repeated low dose allergen exposure. Inhibition of the airway response was unspecific to exposed allergen and independent of histamine receptor blocking. Furthermore, a significant reduction of cysteinyl leukotrienes and TXB2 was found in the airways of animals repeatedly exposed to a low dose allergen. However, in vitro stimulation of airway tissue from animals repeatedly exposed to a low dose allergen with arachidonic acid and calcium ionophore (A23187 induced production of cysteinyl leukotrienes and TXB2, suggesting enhanced activity of 5-lipoxygenase and cyclooxygenase pathways. Conclusions The inhibition of the early phase airway response, cysteinyl leukotriene and TXB2 production after repeated allergen exposure may result from unresponsive effector cells.

  10. Repeated prenatal exposure to valproic acid results in cerebellar hypoplasia and ataxia.

    Science.gov (United States)

    Main, Stacey L; Kulesza, Randy J

    2017-01-06

    Autism spectrum disorder (ASD) is a developmental brain disorder characterized by restricted and repetitive patterns of behavior, social and communication defects, and is commonly associated with difficulties with motor coordination. The etiology of ASD, while mostly idiopathic, has been linked to hereditary factors and teratogens, such as valproic acid (VPA). VPA is used clinically to treat epilepsy, mood disorders, and in the prevention of migraines. The use of VPA during pregnancy significantly increases the risk of ASD in the offspring. Neuropathological studies show decreased cerebellar function in patients with ASD, resulting in gait, balance and coordination impairments. Herein, we have exposed pregnant rats to a repeated oral dose of VPA on embryonic days 10 and 12 and performed a detailed investigation of the structure and function of the cerebellar vermis. We found that throughout all ten lobules of the cerebellar vermis, Purkinje cells were significantly smaller and expression of the calcium binding protein calbindin (CB) was significantly reduced. We also found that dendritic arbors of Purkinje cells were shorter and less complex. Additionally, animals exposed to a repeated dose of VPA performed significantly worse in a number of motor tasks, including beam walking and the rotarod. These results suggest that repeated embryonic exposure to VPA induces significant cerebellar dysfunction and is an effective animal model to study the cerebellar alterations in ASD. Copyright © 2016 IBRO. Published by Elsevier Ltd. All rights reserved.

  11. Clementine auto exposure control software

    Energy Technology Data Exchange (ETDEWEB)

    Arnold, E. [Lawrence Livermore National Lab., CA (United States)

    1994-11-15

    The primary mission of the Clementine program was to test technology developed under the auspices of BMDO (the Ballistic Missile Defense Organization). A secondary goal of the program was to provide astronomical data to the scientific and educational community. The mission plan developed to accomplish these goals included complete mapping of the lunar surface and a close fly-by of a near-Earth asteroid, 1620 Geographos. Exposure control for the Clementine mission was driven by mission phase requirements and sensor characteristics. Thus, there were a total of twelve algorithms developed for three primary mission phases and the four imaging sensors (two additional sensors operated as star trackers). The three mission phases in question were lunar mapping, distant observation of the asteroid for the purpose of tracking, and close-up viewing (as close as 100 Km) of Geographos. The four non-star tracker sensors consisted of an Ultra Violet/Visible (UV/Vis) camera, a High Resolution (HiRes) camera with a built-in LIDAR (Light Detection And Ranging) unit, a Near Infrared (NIR) camera, and a Long Wave InfraRed (LWIR) camera. Due to lack of test time and uncertainties about the imaging environment, numerous input parameters were provided in the algorithms to allow extensive tuning of the exposure control during the mission.

  12. Physiological responses and manual performance in humans following repeated exposure to severe cold at night.

    Science.gov (United States)

    Ozaki, H; Nagai, Y; Tochihara, Y

    2001-04-01

    We evaluated human physiological responses and the performance of manual tasks during exposure to severe cold (-25 degrees C) at night (0300-0500 hours) and in the afternoon (1500-1700 hours). Thirteen male students wearing standard cold protective clothing occupied a severely cold room (-25 degrees C) for 20 min, and were then transferred to a cool room (10 degrees C) for 20 min. This pattern of exposure was repeated three times, for a total time of exposure to extreme cold of 60 min. The experiments were started either at 1500 hours or 0300 hours and measurements of rectal temperature, skin temperature, blood pressure, performance in a counting task, hand tremor, and subjective responses were made in each condition. At the end of the experiment at night the mean decrease in rectal temperature [0.68 (SEM 0.04) degree C] was significantly greater than that at the end of the experiment in the afternoon [0.55 (SEM 0.08) degree C, P second cold exposure at night the mean increase in diastolic blood pressure [90 (SEM 2.0) mmHg] was significantly greater than that at the end of the second cold exposure in the afternoon [82 (SEM 2.8) mmHg, P second cold exposure at night, mean finger skin temperature [11.8 (SEM 0.8) degrees C] was significantly higher than that at the comparable time in the afternoon [9.0 (SEM 0.7) degrees C, P second cold exposure at night [25.6 (SEM 1.5) degrees C] was significantly higher than in the afternoon [20.1 (SEM 0.8) degrees C, P < 0.01]. The increased skin temperatures in the periphery resulted in increased heat loss. Since peripheral skin temperatures were highest at night, the subjects noted diminished sensations of thermal cold and pain at that time. Manual dexterity at the end of the first cold exposure at night [mean 83.7 (SEM 3.6) times.min-1] had decreased significantly more than at the end of the first cold exposure in the afternoon [mean 89.4 (SEM 3.5) times.min-1, P < 0.01]. These findings of a lowered rectal temperature and

  13. The role of temporal delay and repeated prospective memory cue exposure on the deactivation of completed intentions.

    Science.gov (United States)

    Walser, Moritz; Plessow, Franziska; Goschke, Thomas; Fischer, Rico

    2014-07-01

    Previous studies have shown that completed prospective memory (PM) intentions entail aftereffects in terms of ongoing-task-performance decrements in trials containing repeated PM cues which previously served as PM cues triggering the intended action. Previous research reported that PM aftereffects decrease over time, thus revealing a specific time course of PM aftereffects. In the present study, we tested two accounts for this pattern, assuming either that the decline of aftereffects is related to the temporal distance to PM task completion or may be a result of the repeated exposure of repeated PM cues in the ongoing task. In three experiments, we manipulated both the temporal distance to PM task completion and the frequency of repeated PM cues and demonstrated that aftereffects of completed intentions declined with repeated exposure of formerly relevant PM cues. In addition, effects of repeated exposure were not only limited to the repetition of specific PM-cue exemplars but also generalized to other semantically related PM cues within the PM-cue category. Together, findings show that decreased aftereffects of completed intentions are not related to the temporal duration of the subsequent test block, but crucially depend on the repeated exposure of the previously relevant PM cues.

  14. Trends in occupational exposure control

    International Nuclear Information System (INIS)

    Wrixon, A.D.

    1996-01-01

    The latest recommendations of the International Commission on Radiological Protection were agreed in 1990. A major component was the revision of its recommended dose limits, prompted by the revised risk factors relating to exposure to ionising radiation that became available in the second half of the 1980s. But other changes were introduced which necessitated development. In particular a Task Group has been developing guidance on the implementation of the recommendations relating to the protection of workers. This guidance is intended to replace that given in Publication 35. The proposed guidance will be considered by ICRP at its meeting in Paris in November 1996. A guide on occupational radiation protection is also being prepared by the International Atomic Energy Agency. The intention is to develop the principles given in the International Basic Safety Standards for Protection against Ionizing Radiation and for the Safety of Radiation Sources, account being taken of the work of the ICRP Task Group. Members States of the European Communities are obliged to comply with the requirements of a Directive dealing with the basic standards for radiation protection. This Directive has recently been revised in the light of the ICRP recommendations. This paper will discuss these developments and their possible impact on the control of occupational exposure in the UK. (author)

  15. Thermal responses from repeated exposures to severe cold with intermittent warmer temperatures.

    Science.gov (United States)

    Ozaki, H; Enomoto-Koshimizu, H; Tochihara, Y; Nakamura, K

    1998-09-01

    This study was conducted to evaluate physiological reaction and manual performance during exposure to warm (30 degrees C) and cool (10 degrees C) environments after exposure to very low temperatures (-25 degrees C). Furthermore, this experiment was conducted to study whether it is desirable to remove cold-protective jackets in warmer rooms after severe cold exposure. Eight male students remained in an extremely cold room for 20 min, after which they transferred into either the warm room or the cool room for 20 min. This pattern was repeated three times, and the total cold exposure time was 60 min. In the warm and cool rooms, the subjects either removed their cold-protective jackets (Condition A), or wore them continuously (Condition B). Rectal temperature, skin temperatures, manual performance, blood pressure, thermal, comfort and pain sensations were measured during the experiment. The effects of severe cold on almost all measurements in the cool (10 degrees C) environment were greater than those in the warm (30 degrees C) environment under both clothing conditions. The effects of severe cold on all measurements under Condition A except rectal temperature and toe skin temperature were significantly greater than those under Condition B in the cool environment but, not at all differences between Condition A and Condition B in the warm environments were significant. It was recognized that to remove cold-protective jackets in the cool room (10 degrees C) after severe cold exposure promoted the effects of severe cold. When rewarming in the warm resting room (30 degrees C), the physiological and psychological responses and manual performance were not influenced by the presence or absence of cold-protective clothing. These results suggest that it is necessary for workers to make sure to rewarm in the warm room outside of the cold storage and continue to wear cold-protective clothing in the cool room.

  16. 17β-Estradiol is required for the sexually dimorphic effects of repeated binge-pattern alcohol exposure on the HPA axis during adolescence.

    Directory of Open Access Journals (Sweden)

    Magdalena M Przybycien-Szymanska

    Full Text Available Alcohol consumption during adolescence has long-term sexually dimorphic effects on anxiety behavior and mood disorders. We have previously shown that repeated binge-pattern alcohol exposure increased the expression of two critical central regulators of stress and anxiety, corticotrophin-releasing hormone (CRH and arginine vasopressin (AVP, in adolescent male rats. By contrast, there was no effect of alcohol on these same genes in adolescent females. Therefore, we tested the hypothesis that 17β-estradiol (E(2, the predominant sex steroid hormone in females, prevents alcohol-induced changes in CRH and AVP gene expression in the paraventricular nucleus (PVN of the hypothalamus. To test this hypothesis, postnatal day (PND 26 females were ovariectomized and given E(2 replacement or cholesterol as a control. Next, they were given an alcohol exposure paradigm of 1 saline alone, 2 acute (single dose or 3 a repeated binge-pattern. Our results showed that acute and repeated binge-pattern alcohol treatment increased plasma ACTH and CORT levels in both E(2- and Ch-treated groups, however habituation to repeated binge-pattern alcohol exposure was evident only in E(2-treated animals. Further, repeated binge-pattern alcohol exposure significantly decreased CRH and AVP mRNA in Ch-, but not E(2-treated animals, which was consistent with our previous observations in gonad intact females. We further tested the effects of E(2 and alcohol treatment on the activity of the wild type CRH promoter in a PVN-derived neuronal cell line. Alcohol increased CRH promoter activity in these cells and concomitant treatment with E(2 completely abolished the effect. Together our data suggest that E(2 regulates the reactivity of the HPA axis to a repeated stressor through modulation of the habituation response and further serves to maintain normal steady state mRNA levels of CRH and AVP in the PVN in response to a repeated alcohol stressor.

  17. Automatic Exposure Control Devices for Digital Mammography

    National Research Council Canada - National Science Library

    Fajardo, Laurie

    2000-01-01

    Purpose: The broad, long-term objective of this IDEA proposal is to achieve optimized image quality for DM within acceptable limits of radiation exposure by developing innovative approaches for controlling DM exposures. Scope...

  18. The mere exposure effect for consumer products as a consequence of existing familiarity and controlled exposure.

    Science.gov (United States)

    Hekkert, Paul; Thurgood, Clementine; Whitfield, T W Allan

    2013-10-01

    The finding that repeated exposure to a stimulus enhances attitudes directed towards it is a well-established phenomenon. Despite this, the effects of exposure to products are difficult to determine given that they could have previously been exposed to participants any number of times. Furthermore, factors other than simple repeated exposure can influence affective evaluations for stimuli that are meaningful. In our first study, we examined the influence of existing familiarity with common objects and showed that the attractiveness of shapes representing common objects increases with their rated commonness. In our second study, we eliminated the effects of prior exposure by creating fictitious yet plausible products; thus, exposure frequency was under complete experimental control. We also manipulated the attention to be drawn to the products' designs by placing them in contexts where their visual appearance was stressed to be important versus contexts in which it was indicated that little attention had been paid to their design. Following mere exposure, attractiveness ratings increased linearly with exposure frequency, with the slope of the function being steeper for stimuli presented in an inconspicuous context-indicating that individuals engage in more deliberate processing of the stimuli when attention is drawn to their visual appearance. © 2013 Elsevier B.V. All rights reserved.

  19. Mast Cells Limit the Exacerbation of Chronic Allergic Contact Dermatitis in Response to Repeated Allergen Exposure.

    Science.gov (United States)

    Gimenez-Rivera, Vladimir-Andrey; Siebenhaar, Frank; Zimmermann, Carolin; Siiskonen, Hanna; Metz, Martin; Maurer, Marcus

    2016-12-01

    Allergic contact dermatitis is a chronic T cell-driven inflammatory skin disease that is caused by repeated exposure to contact allergens. Based on murine studies of acute contact hypersensitivity, mast cells (MCs) are believed to play a role in its pathogenesis. The role of MCs in chronic allergic contact dermatitis has not been investigated, in part because of the lack of murine models for chronic contact hypersensitivity. We developed and used a chronic contact hypersensitivity model in wild-type and MC-deficient mice and assessed skin inflammatory responses to identify and characterize the role of MCs in chronic allergic contact dermatitis. Ear swelling chronic contact hypersensitivity responses increased markedly, up to 4-fold, in MC-deficient Kit W-sh/W-sh (Sash) and MCPT5-Cre + iDTR + mice compared with wild-type mice. Local engraftment with MCs protected Sash mice from exacerbated ear swelling after repeated oxazolone challenge. Chronic contact hypersensitivity skin of Sash mice exhibited elevated levels of IFN-γ, IL-17α, and IL-23, as well as increased accumulation of Ag-specific IFN-γ-producing CD8 + tissue-resident memory T (T RM ) cells. The CD8 + T cell mitogen IL-15, which was increased in oxazolone-challenged skin of Sash mice during the accumulation of cutaneous T RM cells, was efficiently degraded by MCs in vitro. MCs protect from the exacerbated allergic skin inflammation induced by repeated allergen challenge, at least in part, via effects on CD8 + T RM cells. MCs may notably influence the course of chronic allergic contact dermatitis. A better understanding of their role and the underlying mechanisms may lead to better approaches for the treatment of this common, disabling, and costly condition. Copyright © 2016 by The American Association of Immunologists, Inc.

  20. Repeated exposure to iron oxide nanoparticles causes testicular toxicity in mice.

    Science.gov (United States)

    Sundarraj, Kiruthika; Manickam, Vijayprakash; Raghunath, Azhwar; Periyasamy, Madhivadhani; Viswanathan, Mangala Priya; Perumal, Ekambaram

    2017-02-01

    The aim of this study was to determine whether repeated exposure to iron oxide nanoparticles (Fe 2 O 3 -NPs) could be toxic to mice testis. Fe 2 O 3 -NPs (25 and 50 mg/kg) were intraperitoneally administered into mice once a week for 4 weeks. Our study showed that Fe 2 O 3 -NPs have the ability to cross the blood-testis barrier to get into the testis. The findings showed that exposure resulted in the accumulation of Fe 2 O 3 -NPs which was evidenced from the iron content and accumulation in the testis. Furthermore, 25 and 50 mg/kg Fe 2 O 3 -NPs administration increased the reactive oxygen species, lipid peroxidation, protein carbonyl content, glutathione peroxidase activity, and nitric oxide levels with a concomitant decrease in the levels of antioxidants-superoxide dismutase, catalase, glutathione, and vitamin C. Increased expression of Bax, cleaved-caspase-3, and cleaved-PARP confirms apoptosis. Serum testosterone levels increased with increased concentration of Fe 2 O 3 -NPs exposure. In addition, the histopathological lesions like vacuolization, detachment, and sloughing of germ cells were also observed in response to Fe 2 O 3 -NPs treatment. The data from our study entailed that testicular toxicity caused by Fe 2 O 3 -NPs exposure may be associated with Fe 2 O 3 -NPs accumulation leading to oxidative stress and apoptosis. Therefore, precautions should be taken in the safe use of Fe 2 O 3 -NPs to avoid complications in the fertility of males. Further research will unravel the possible molecular mechanisms on testicular toxicity of Fe 2 O 3 -NPs. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 594-608, 2017. © 2016 Wiley Periodicals, Inc.

  1. Effect of squatting on sprinting performance and repeated exposure to complex training in male rugby players.

    Science.gov (United States)

    Comyns, Thomas M; Harrison, Andrew J; Hennessy, Liam K

    2010-03-01

    This study was undertaken to examine the effect of a heavy weight training exercise on sprinting performance and on the effect of repeated exposure to a complex training protocol. Eleven male rugby union players (age 20.9 +/- 3.1 years) participated in the study, which involved 5 separate testing sessions. Back squat 3 repetition maximum (3RM) was established in session 1. Sessions 2-5 were identical and involved the subjects completing a 30-m sprint before and after a 3RM back squat protocol. Four minutes of rest was given between the back squatting and the posttest 30-m sprint. All sprint trials were measured with a laser measurement device (LAVEG, Jenoptik, Jena, Germany). Sprint time and instantaneous, average, and maximum velocity were the dependent variables. The criterion for significance was set at an alpha level of p > or = 0.05. No significant improvement was evident for any of the testing sessions (p > or = 0.05). In session 1, there was a significant increase in 30-m time and a significant reduction in average 30-m velocity and maximum velocity (p benefits in sprinting may not have been realized because of intra and intersubject variations in sprint technique. The session x phase interaction revealed a significant improvement in the pre to posttest changes in instantaneous velocity at 20 m (p = 0.035) and 30 m (p = 0.036) from session 1 to session 4. This indicates that the rugby players may be able to learn to apply the potentiation effects of complex training. From a practical perspective, players may need repeated exposure to this training modality to gain benefit from it, and this should be reflected in program planning.

  2. Protective effect of SP600125 against liver cell injury in rats under repeated and sustained high +Gz exposure

    Directory of Open Access Journals (Sweden)

    Wen-bing LI

    2015-01-01

    Full Text Available Objective To explore the effect of JNK inhibitor SP600125 on expression of JNK/c-jun in liver cells of rats under repeated and sustained high +Gz exposure and its mechanism of the effect. Methods Eighteen inbred adult male Wistar rats were randomly divided into control group, +10Gz group and SP600125 group (n=6. The rats in +10Gz group and SP600125 group were fixed to the rotating arm of a centrifuge with head towards the axis. The increase rate of acceleration was 1G/s with a peak-time of 3 minutes, and the +Gz exposure was repeated 5 times with an interval of 30 minutes. SP600125 was given to rats of SP600125 group 30 minutes before the first centrifugation by intraperitoneal injection. All of the animals were sacrificed 30 minutes after centrifugation. Blood samples were collected from inferior vena cava to determine the plasma level of aspartate aminotransferase (AST and alanine aminotransferase (ALT. The expression of c-jun mRNA was determined by quantitative real-time RT-PCR (qRTPCR. The expressions of p-JNK, JNK, p-c-jun and c-jun protein were determined by Western blotting. The morphological change in the liver tissue was observed after HE staining. Results The plasma level of ALT and AST, expression level of c-jun mRNA and p-JNK, p-c-jun, c-jun protein in the liver tissue of SP600125 group were significantly higher than those of control group (P0.05. HE staining revealed disorganized hepatic cords, irregular liver cells, vacuolar changes, and marked edema of hepatocytes, and collapsed hepatic sinusoids in +10Gz group, but these changes were alleviated obviously in SP600125 group. Conclusion SP600125 could alleviate the liver cell injury in rats under repeated and sustained high +Gz exposure. DOI: 10.11855/j.issn.2577-7402.2014.11.02

  3. Fatal cardiac arrhythmia after repeated exposure to 1,1-difluoroethane (DFE).

    Science.gov (United States)

    Avella, Joseph; Wilson, James C; Lehrer, Michael

    2006-03-01

    A 42-year-old man was found dead after repeated exposure to 1,1-difluoroethane (DFE, Freon 152a), a propellant found in CRC Duster, a product intended for the removal of dust and lint. Toxicologic analysis detected DFE in femoral blood 136.3 mg/L, brain 117.5 mg/kg, liver 87.6 mg/kg, lung 60.3 mg/kg, adipose 235.7 mg/kg, and vitreous fluid 25.1 mg/L. The cause of death was determined to be a fatal cardiac arrhythmia due to intoxication with 1,1-difluoroethane. After comparison to previously published cases involving DFE, we suggest that analysis of adipose tissue for DFE and similar compounds, along with blood and other tissues, may be useful in distinguishing between acute versus chronic exposure. Adipose may also be a valuable alternate specimen for detection in cases where loss or elimination from blood is likely to have occurred.

  4. Occupational hazards of traditional healers: repeated unprotected blood exposures risk infectious disease transmission.

    Science.gov (United States)

    Audet, Carolyn M; Salato, José; Blevins, Meridith; Silva, Wilson; González-Calvo, Lázaro; Vermund, Sten H; Gaspar, Felisbela

    2016-11-01

    Healers provide support for acute and chronic illnesses in rural Mozambique, such as socially acceptable traditional 'vaccinations' (subcutaneous cuts in the skin to rub herbs directly into the bloody lesion). We aimed to document the frequency of blood exposure by traditional practitioners in Mozambique. We conducted surveys with a simple random sample of 236 traditional healers in Zambézia province. Chi-square and Wilcoxon rank-sum tests were used to compare 'injection' behaviours across districts. Healers treated a median of eight patients in the past month (IQR: 4-15). About 75% conducted 'injections'. These healers 'injected' a median of four patients (IQR: 1-8), used a new razor a median of three times (IQR: 1-8), and almost never used gloves. Lifetime blood exposures among those who provided 'injections' during treatments were estimated to be 1758 over a healer's career. The majority of healers are exposed repeatedly to patient blood. Given the high prevalence of HIV, hepatitis B and C virus, and other blood-borne agents, specific healer practices are an occupational hazard and reuse of razors is risky for their clients. © 2016 John Wiley & Sons Ltd.

  5. Repeated Exposure to Dissection Does Not Influence Students' Attitudes towards Human Body Donation for Anatomy Teaching

    Science.gov (United States)

    Mwachaka, Philip Maseghe; Mandela, Pamela; Saidi, Hassan

    2016-01-01

    The use of unclaimed bodies for anatomical dissection has been the main method of instruction at our institution. There is however a shortage of cadavers for dissection given the increase in the number of medical schools as well as in the number of students enrolling in these schools. This shortage could be mitigated by having voluntary human body donation programs. This study aimed at assessing the attitudes of medical students and surgical residents towards body donation for anatomy learning. We conducted an online survey involving 72 first-year medical students and 41 surgical residents at University of Nairobi who had completed one year of anatomy dissection. For the medical students, this was their first dissection experience while it was the second exposure for the surgery trainees. Most of the surgical trainees (70.7%) and medical students (68.1%) were opposed to self-body donation. This was mainly due to cultural (37%) and religious (20%) barriers. Surprisingly, of those not willing to donate themselves, 67.9% (82.8% surgical trainees, 59.2% medical students) would recommend the practice to other people. Exposure to repeated dissection does not change the perceptions towards body donation. It is noteworthy that culture and religion rank high as clear barriers amongst this “highly informed” group of potential donors. PMID:27190650

  6. Repeated Exposure to Dissection Does Not Influence Students' Attitudes towards Human Body Donation for Anatomy Teaching.

    Science.gov (United States)

    Mwachaka, Philip Maseghe; Mandela, Pamela; Saidi, Hassan

    2016-01-01

    The use of unclaimed bodies for anatomical dissection has been the main method of instruction at our institution. There is however a shortage of cadavers for dissection given the increase in the number of medical schools as well as in the number of students enrolling in these schools. This shortage could be mitigated by having voluntary human body donation programs. This study aimed at assessing the attitudes of medical students and surgical residents towards body donation for anatomy learning. We conducted an online survey involving 72 first-year medical students and 41 surgical residents at University of Nairobi who had completed one year of anatomy dissection. For the medical students, this was their first dissection experience while it was the second exposure for the surgery trainees. Most of the surgical trainees (70.7%) and medical students (68.1%) were opposed to self-body donation. This was mainly due to cultural (37%) and religious (20%) barriers. Surprisingly, of those not willing to donate themselves, 67.9% (82.8% surgical trainees, 59.2% medical students) would recommend the practice to other people. Exposure to repeated dissection does not change the perceptions towards body donation. It is noteworthy that culture and religion rank high as clear barriers amongst this "highly informed" group of potential donors.

  7. Repeated exposures to roadside particulate matter extracts suppresses pulmonary defense mechanisms, resulting in lipid and protein oxidative damage.

    Science.gov (United States)

    Pardo, Michal; Porat, Ziv; Rudich, Assaf; Schauer, James J; Rudich, Yinon

    2016-03-01

    Exposure to particulate matter (PM) pollution in cities and urban canyons can be harmful to the exposed population. However, the underlying mechanisms that lead to health effects are not yet elucidated. It is postulated that exposure to repeated, small, environmentally relevant concentrations can affect lung homeostasis. This study examines the impact of repeated exposures to urban PM on mouse lungs with focus on inflammatory and oxidative stress parameters. Aqueous extracts from collected urban PM were administered to mice by 5 repeated intra-tracheal instillations (IT). Multiple exposures, led to an increase in cytokine levels in both bronchoalveolar lavage fluid and in the blood serum, indicating a systemic reaction. Lung mRNA levels of antioxidant/phase II detoxifying enzymes decreased by exposure to the PM extract, but not when metals were removed by chelation. Finally, disruption of lung tissue oxidant-inflammatory/defense balance was evidenced by increased levels of lipid and protein oxidation. Unlike response to a single IT exposure to the same dose and source of extract, multiple exposures result in lung oxidative damage and a systemic inflammatory reaction. These could be attributed to compromised capacity to activate the protective Nrf2 tissue defense system. It is suggested that water-soluble metals present in urban PM, potentially from break and tire wear, may constitute major drivers of the pulmonary and systemic responses to multiple exposure to urban PM. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Prior exposure to repeated immobilization or chronic unpredictable stress protects from some negative sequels of an acute immobilization.

    Science.gov (United States)

    Pastor-Ciurana, Jordi; Rabasa, Cristina; Ortega-Sánchez, Juan A; Sanchís-Ollè, Maria; Gabriel-Salazar, Marina; Ginesta, Marta; Belda, Xavier; Daviu, Núria; Nadal, Roser; Armario, Antonio

    2014-05-15

    Exposure to chronic unpredictable stress (CUS) is gaining acceptance as a putative animal model of depression. However, there is evidence that chronic exposure to stress can offer non-specific stress protection from some effects of acute superimposed stressors. We then compared in adult male rats the protection afforded by prior exposure to CUS with the one offered by repeated immobilization on boards (IMO) regarding some of the negative consequences of an acute exposure to IMO. Repeated exposure to IMO protected from the negative consequences of an acute IMO on activity in an open-field, saccharin intake and body weight gain. Active coping during IMO (struggling) was markedly reduced by repeated exposure to the same stressor, but it was not affected by a prior history of CUS, suggesting that our CUS protocol does not appear to impair active coping responses. CUS exposure itself caused a strong reduction of activity in the open-field but appeared to protect from the hypo-activity induced by acute IMO. Moreover, prior CUS offered partial protection from acute IMO-induced reduction of saccharin intake and body weight gain. It can be concluded that a prior history of CUS protects from some of the negative consequences of exposure to a novel severe stressor, suggesting the development of partial cross-adaptation whose precise mechanisms remain to be studied. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Impact of product information and repeated exposure on consumer liking, sensory perception and concept associations of local apple juice

    DEFF Research Database (Denmark)

    Stolzenbach, Sandra; Bredie, Wender Laurentius Petrus; Christensen, Rune Haubo Bojesen

    2013-01-01

    The impact of product information and repeated exposure of local apple juice on consumer liking, sensory perception and concept associations was studied. Findings showed that consumers had high expectations towards the studied local apples juices. Consequently, the liking for the local apple juices...... did not fully determine consumer liking. Thus the sensory characteristics were also found to be of importance. Besides liking, the concept associations were also affected by product information. All local apple juices were associated as being more exclusive under informed tasting conditions....... No effects were found for liking of the apple juices over repeated exposure. Also, the consumers did not change their sensory perception over repeated consumption. However, the local apple juices were conceptualised as more familiar but remained exclusive after repeated consumption. When local producers have...

  10. Is repeated exposure the holy grail for increasing children's vegetable intake? Lessons learned from a Dutch childcare intervention using various vegetable preparations.

    Science.gov (United States)

    Zeinstra, Gertrude G; Vrijhof, Milou; Kremer, Stefanie

    2018-02-01

    Children's failure to eat enough vegetables highlights the need for effective interventions encouraging this behaviour. The aim of this study was to investigate the effect of repeated exposure to three a priori unfamiliar vegetables, each prepared in two ways, on children's vegetable acceptance in a childcare setting. Two hundred fifty children (mean age 25 months; 57% boys) participated in a pre-test and a post-test, where they were offered pumpkin, courgette, and white radish. The intervention group (N = 125) participated in a 5-month exposure period, where they were exposed repeatedly (∼12x) to the vegetables: pumpkin blanched and as a cracker spread; courgette blanched and as soup; white radish raw and as a cracker spread. The control group (N = 125) maintained their normal routine. Mixed model analyses were used to analyse intake data and Chi-square analyses for willingness to taste. At pre-test, children ate about 20 g of pumpkin and courgette, whereas white radish intake was approximately 10 g. There was a significant positive effect of the intervention for pumpkin (+15 g; p < 0.001) and white radish (+16 g; p = 0.01). Results for willingness to taste were in the same direction. There was no repeated exposure effect for courgette (p = 0.54); this may have been due to its less distinct taste profile or familiarity with boiled courgette. From our findings, we conclude that repeated exposure to multiple unfamiliar vegetable tastes within the daily routine of a childcare setting is effective in improving children's willingness to taste and intake of some of these vegetables. However, repeated exposure may not be sufficient for more familiar or blander tasting vegetables. This implies that one size does not fit all and that additional strategies are needed to increase children's intake of these vegetables. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Repeated exposures to cobalt or chromate on the hands of patients with hand eczema and contact allergy to that metal

    DEFF Research Database (Denmark)

    Nielsen, N H; Kristiansen, J; Borg, L

    2000-01-01

    The present study aimed at evaluating the effects of daily repeated exposures to low cobalt or chromate concentrations on the hands of patients with hand eczema and cobalt or chromate allergy. For 2 weeks, the patients immersed a finger for 10 min daily into the appropriate metal salt solution in...... of providing evidence-based medicine in the area of allergic contact dermatitis in the future.......-sensitive patients. During the exposure period, accumulation of cobalt or chromate in the nail was demonstrated. Standardization of chemical methods of quantification of skin exposure to allergens, combined with experimental exposure studies in patients with specific contact allergy, will increase the possibility...

  12. Deterioration of neurobehavioral performance in resident physicians during repeated exposure to extended duration work shifts.

    Science.gov (United States)

    Anderson, Clare; Sullivan, Jason P; Flynn-Evans, Erin E; Cade, Brian E; Czeisler, Charles A; Lockley, Steven W

    2012-08-01

    Although acute sleep loss during 24- to 30-h extended duration work shifts (EDWS) has been shown to impair the performance of resident physicians, little is known about the effects of cumulative sleep deficiency on performance during residency training. Chronic sleep restriction induces a gradual degradation of neurobehavioral performance and exacerbates the effects of acute sleep loss in the laboratory, yet the extent to which this occurs under real-world conditions is unknown. In this study, the authors quantify the time course of neurobehavioral deterioration due to repeated exposure to EDWS during a 3-week residency rotation. A prospective, repeated-measures, within-subject design. Medical and cardiac intensive care units, Brigham and Women's Hospital, Boston, MA. Thirty-four postgraduate year one resident physicians (23 males; age 28.0 ± 1.83 (standard deviation) years) Residents working a 3-week Q3 schedule (24- to 30-h work shift starts every 3(rd) day), consisting of alternating 24- to 30-h (EDWS) and approximately 8-h shifts, underwent psychomotor vigilance testing before, during, and after each work shift. Mean response time, number of lapses, and slowest 10% of responses were calculated for each test. Residents also maintained daily sleep/wake/work logs. EDWS resulted in cumulative sleep deficiency over the 21-day rotation (6.3 h sleep obtained per day; average 2.3 h sleep obtained per extended shift). Response times deteriorated over a single 24- to 30-h shift (P Performance on the fifth and sixth shift was significantly worse than on the first shift (P performance and exacerbated the effects of acute sleep loss inherent in the 24- to 30-h EDWS that are commonly used in resident schedules.

  13. Gender-specific association of functional prodynorphin 68 bp repeats with cannabis exposure in an African American cohort.

    Science.gov (United States)

    Yuferov, Vadim; Butelman, Eduardo R; Kreek, Mary Jeanne

    2018-01-01

    Cannabis use disorders (CUDs) cause substantial neuropsychiatric morbidity and comorbidity. There is evidence for gender-based differences in CUDs, for instance, a greater prevalence in males than in females. The main active component of cannabis is delta 9-tetrahydrocannabinol (delta 9-THC), a partial agonist of the cannabinoid type 1 receptor. Preclinical studies show that genetic or pharmacological manipulation of the kappa opioid receptor/dynorphin system modulates the effects of delta 9-THC. In this case-control study of adult African Americans (n=476; 206 females, 270 males), we examined the association of the functional prodynorphin 68 bp ( PDYN 68 bp) promoter repeats with categorical diagnoses of cannabis dependence ( Diagnostic and Statistical Manual of Mental Disorders-IV criteria), as well as with a rapid dimensional measure of maximum lifetime cannabis exposure (the Kreek-McHugh-Schluger-Kellogg cannabis scale). The PDYN 68 bp genotype (examined as short-short [SS], short-long [SL], or long-long [LL], based on the number of repeats) was not significantly associated with categorical cannabis-dependence diagnoses, either in males or in females. However, in males, the PDYN 68 bp SS+SL genotype was associated with both greater odds of any use of cannabis ( p cannabis use, compared to the LL genotype (ie, 15 versus 16.5 years of age; p cannabis, compared to the LL group ( p cannabis. Overall, this study shows that PDYN 68 bp polymorphisms affect behaviors involved in early stages of nonmedical cannabis use and potentially lead to increasing self-exposure. These data may eventually lead to improvements in personalized medicine for the prevention and treatment of highly prevalent CUDs and neuropsychiatric comorbidities.

  14. Repeated Exposure to Neurotoxic Levels of Chlorpyriphos Alters Hippocampal Expression of Neurotrophins and Neuropeptides

    Science.gov (United States)

    2016-01-13

    hormone bindi Bdnf BDNF Brain-derived neurotrophic factor Mdk MDK Midkine (neurite growth -promoting fa Rbp4 RBP4 Retinol binding protein 4, plasma...cause cholinergic crisis are associated with problems in cognitive function (i.e., learning and memory deficits ), but the biological mechanism(s...neurobehavioral deficits following subchronic exposure to CPF at a level that inhibits hippocampal cholinesterase to less than 20% of control. An equally

  15. Gender-specific association of functional prodynorphin 68 bp repeats with cannabis exposure in an African American cohort

    Directory of Open Access Journals (Sweden)

    Yuferov V

    2018-04-01

    Full Text Available Vadim Yuferov,* Eduardo R Butelman,* Mary Jeanne Kreek Laboratory of the Biology of Addictive Diseases, The Rockefeller University, New York, NY, USA *These authors contributed equally to this work Background: Cannabis use disorders (CUDs cause substantial neuropsychiatric morbidity and comorbidity. There is evidence for gender-based differences in CUDs, for instance, a greater prevalence in males than in females. The main active component of cannabis is delta 9-tetrahydrocannabinol (delta 9-THC, a partial agonist of the cannabinoid type 1 receptor. Preclinical studies show that genetic or pharmacological manipulation of the kappa opioid receptor/dynorphin system modulates the effects of delta 9-THC. Methods: In this case-control study of adult African Americans (n=476; 206 females, 270 males, we examined the association of the functional prodynorphin 68 bp (PDYN 68 bp promoter repeats with categorical diagnoses of cannabis dependence (Diagnostic and Statistical Manual of Mental Disorders-IV criteria, as well as with a rapid dimensional measure of maximum lifetime cannabis exposure (the Kreek–McHugh–Schluger–Kellogg cannabis scale. Results: The PDYN 68 bp genotype (examined as short–short [SS], short–long [SL], or long–long [LL], based on the number of repeats was not significantly associated with categorical cannabis-dependence diagnoses, either in males or in females. However, in males, the PDYN 68 bp SS+SL genotype was associated with both greater odds of any use of cannabis (p<0.05 and earlier age of first cannabis use, compared to the LL genotype (ie, 15 versus 16.5 years of age; p<0.045. Males in the SS+SL group also had greater odds of high lifetime exposure to cannabis, compared to the LL group (p<0.045. Of interest, none of the aforementioned genetic associations were significant in females. Conclusion: This study provides the first data on how the PDYN 68 bp genotype is associated with gender-specific patterns of

  16. An observation of histological evidence on internal organ damages in mice caused by repeated exposures to motorcycle emissions

    Science.gov (United States)

    Wardoyo, Arinto Y. P.; Juswono, Unggul P.; Noor, Johan A. E.

    2017-05-01

    Motor vehicle emissions have been identified as a source of ultrafine particles, which have significant impacts on human health. Repeated and prolonged exposure to ultrafine particles may have a significant association with organ damage. Here, we evaluated the correlation between repeated exposure to ultrafine particles and organ damage in mice. Motorcycle emissions were injected into an exposure chamber with mice for a period of 20 seconds. This treatment was conducted over 10 days. The mice were sacrificed on the 2nd, 4th, 6th, 8th, and 10th days for organ preparations. Based on the results, motorcycle emission exposure caused organ damage in mice, with different severities depending on the organ. The highest damage was found for the lung, followed by the kidney, erythrocytes, and liver.

  17. Double blind placebo controlled exposure to molds

    DEFF Research Database (Denmark)

    Meyer, H W; Jensen, K A; Nielsen, K F

    2005-01-01

    non-significant, and at the same level as after placebo exposure. The developed exposure system based on the Particle-Field and Laboratory Emission Cell (P-FLEC) makes it possible to deliver a precise and highly controlled dose of mold spores from water-damaged building materials, imitating realistic......The objective was to develop an experimental setup for human exposure to mold spores, and to study the clinical effect of this exposure in sensitive subjects who had previously experienced potentially building-related symptoms (BRS) at work. From three water-damaged schools eight employees....... In conclusion this is, to our knowledge, the first study to successfully conduct a human exposure to a highly controlled dose of fungal material aerosolized directly from wet building materials. This short-term exposure to high concentrations of two different molds induced no more reactions than exposure...

  18. Techniques for controlling radiation exposure

    International Nuclear Information System (INIS)

    Ocken, H.; Wood, C.J.

    1993-01-01

    The US nuclear power industry has been remarkably successful in reducing worker radiation exposure over the past 10 years. There has been more than a fourfold reduction in person-rem per MW-year of electric power generated: from 1.8 person-rems in 1980 to only 0.4 person-rems in 1991. Despite this substantial improvement, challenges for the industry remain. Individual exposure limits have been tightened in the 1990 Recommendations of the International Commission on Radiological Protection, ICRP Publication 60, and there will be more requirements for special maintenance work as plants age, suggesting that vigorous efforts will be required to meet the 1995 industry goals for unit median collective exposure. No one method will suffice, but implementing suitable combinations from this compendium will help utilities to achieve their exposure goals. Radiation reduction is generally cost-effective: Outages are shorter, staffing requirements are reduced, and work quality is improved. Despite up-front costs, the benefits over the following one to three years typically outweigh the expenses

  19. Hearing loss associated with repeated MRI acquisition procedure-related acoustic noise exposure: an occupational cohort study

    NARCIS (Netherlands)

    Bongers, Suzan; Slottje, Pauline; Kromhout, Hans

    2017-01-01

    OBJECTIVE: To study the effects of repeated exposure to MRI-related acoustic noise during image acquisition procedures (scans) on hearing. METHODS: A retrospective occupational cohort study was performed among workers of an MRI manufacturing facility (n=474). Longitudinal audiometry data from the

  20. Writing content predicts benefit from written expressive disclosure: Evidence for repeated exposure and self-affirmation.

    Science.gov (United States)

    Niles, Andrea N; Byrne Haltom, Kate E; Lieberman, Matthew D; Hur, Christopher; Stanton, Annette L

    2016-01-01

    Expressive disclosure regarding a stressful event improves psychological and physical health, yet predictors of these effects are not well established. The current study assessed exposure, narrative structure, affect word use, self-affirmation and discovery of meaning as predictors of anxiety, depressive and physical symptoms following expressive writing. Participants (N = 50) wrote on four occasions about a stressful event and completed self-report measures before writing and three months later. Essays were coded for stressor exposure (level of detail and whether participants remained on topic), narrative structure, self-affirmation and discovery of meaning. Linguistic Inquiry and Word Count software was used to quantify positive and negative affect word use. Controlling for baseline anxiety, more self-affirmation and detail about the event predicted lower anxiety symptoms, and more negative affect words (very high use) and more discovery of meaning predicted higher anxiety symptoms three months after writing. Findings highlight the importance of self-affirmation and exposure as predictors of benefit from expressive writing.

  1. Repeated exposure to high-frequency spanking and child externalizing behavior across the first decade: a moderating role for cumulative risk.

    Science.gov (United States)

    MacKenzie, Michael J; Nicklas, Eric; Brooks-Gunn, Jeanne; Waldfogel, Jane

    2014-12-01

    This study used the Fragile Families and Child Well-Being Study to examine the effects of repeated exposure to harsh parenting on child externalizing behavior across the first decade of life, and a moderating role for cumulative ecological risk. Maternal report of harsh parenting, defined as high frequency spanking, was assessed at age 1, 3, 5, and 9, along with child externalizing at age 9 (N=2,768). Controlling for gender, race, maternal nativity, and city of residence, we found a cumulative risk index to significantly moderate the effects of repeated harsh parenting on child behavior, with the effects of repeated high-frequency spanking being amplified for those experiencing greater levels of cumulative risk. Harsh parenting, in the form of high frequency spanking, remains a too common experience for children, and results demonstrate that the effects of repeated exposure to harsh parenting across the first decade are amplified for those children already facing the most burden. Copyright © 2014. Published by Elsevier Ltd.

  2. Repeated exposure of adult rats to transient oxidative stress induces various long-lasting alterations in cognitive and behavioral functions.

    Directory of Open Access Journals (Sweden)

    Yoshio Iguchi

    Full Text Available Exposure of neonates to oxidative stress may increase the risk of psychiatric disorders such as schizophrenia in adulthood. However, the effects of moderate oxidative stress on the adult brain are not completely understood. To address this issue, we systemically administrated 2-cyclohexen-1-one (CHX to adult rats to transiently reduce glutathione levels. Repeated administration of CHX did not affect the acquisition or motivation of an appetitive instrumental behavior (lever pressing rewarded by a food outcome under a progressive ratio schedule. In addition, response discrimination and reversal learning were not affected. However, acute CHX administration blunted the sensitivity of the instrumental performance to outcome devaluation, and this effect was prolonged in rats with a history of repeated CHX exposure, representing pro-depression-like phenotypes. On the other hand, repeated CHX administration reduced immobility in forced swimming tests and blunted acute cocaine-induced behaviors, implicating antidepressant-like effects. Multivariate analyses segregated a characteristic group of behavioral variables influenced by repeated CHX administration. Taken together, these findings suggest that repeated administration of CHX to adult rats did not cause a specific mental disorder, but it induced long-term alterations in behavioral and cognitive functions, possibly related to specific neural correlates.

  3. 'Just a pinch of salt'. An experimental comparison of the effect of repeated exposure and flavor-flavor learning with salt or spice on vegetable acceptance in toddlers.

    Science.gov (United States)

    Bouhlal, Sofia; Issanchou, Sylvie; Chabanet, Claire; Nicklaus, Sophie

    2014-12-01

    Children's vegetable intake is below the recommended amounts. No studies to date have tested the relevance of using salt or spices to increase children's vegetable acceptance. Our objective was to compare the effect of repeated exposure (RE) and of flavor-flavor learning (FFL) on toddlers' acceptance of a non-familiar vegetable. Two unconditioned stimuli were used: salt and a salt-associated spice. Toddlers attending six nurseries were assigned to 3 groups in a between subject design. Groups were exposed 8 times to a basic salsify puree (0.2% salt w/w; RE group; n = 47), a salty salsify puree (0.5% salt w/w; FFL-Salt group; n = 54) or a spiced salsify puree (0.2% salt and 0.02% nutmeg w/w; FFL-Nutmeg group; n = 50). Acceptance (intake and liking) of the target vegetable (basic salsify puree) and of a control vegetable (carrot puree) was evaluated at pre-exposure, at each exposure of the learning period, at post-exposure, and at 1, 3 and 6 months after exposure. In all groups, intake of the target vegetable increased from pre- to post-exposure. This increase was significantly higher in the RE group (64 ± 11 g) than in the FFL-Salt group (23 ± 11 g) and marginally higher than in the FFL-Nutmeg group (36 ± 11 g). No difference between groups was observed on the increase in liking of the target vegetable from pre- to post-exposure. The increase of the target vegetable intake was still observed after 6 months for all groups. Thus, repeated exposure appears to be the simplest choice to increase vegetable intake on the short and long term in toddlers. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. PET radiation exposure control for nurses

    International Nuclear Information System (INIS)

    Kawabata, Yumiko; Kikuta, Daisuke; Anzai, Taku

    2005-01-01

    Recently, the number of clinical PET centers is increasing all over Japan. For this reason, the monitoring and control of radiation exposure of employees, especially nurses, in PET-dedicated clinics and institutions are becoming very important issues for their health. We measured the radiation exposure doses of the nurses working at Nishidai Diagnostic Imaging Center, and analyzed the exposure data obtained from them. The exposure doses of the nurses were found to be 4.8 to 7.1 mSv between April 2003 and March 2004. We found that the nurses were mostly exposed to radiation when they had to have contact with patients received an FDG injection or they had trouble with the FDG automatic injection system. To keep radiation exposure of nurses to a minimum we reconfirmed that a proper application of the three principles of protection against radiation exposure was vital. (author)

  5. The effects of chronic cadmium exposure on repeat swimming performance and anaerobic metabolism in brown trout (Salmo trutta) and lake whitefish (Coregonus clupeaformis)

    Energy Technology Data Exchange (ETDEWEB)

    Cunningham, Jessie L.; McGeer, James C., E-mail: jmcgeer@wlu.ca

    2016-04-15

    Highlights: • Exposure to 18 nM waterborne Cd induced plasma Ca loss that recovered by day 30 for lake whitefish but not brown trout. • Ucrit measured after an initial swim to 85% of Ucrit and a 30 min rest period was reduced in 18 nM Cd exposed fish compared to controls. • Swimming to 85% of Ucrit resulted in decreased muscle glycogen and increased lactate that was not recovered in the 30 min recovery period. • Second swim impairment is not related to metabolic processes in white muscle. - Abstract: This study investigates the effect of chronic Cd exposure on the ability to perform repeat swim challenges in brown trout (Salmo trutta) and lake whitefish (Coregonus clupeaformis). Fish were exposed to waterborne Cd (18 nM) in moderately hard water (120 mg L{sup −1} CaCO{sub 3}) for 30 days. This level of exposure has been shown to cause sublethal physiological disruption and acclimation responses but no impairment of sustained swimming capacity (U{sub crit}) in single swim challenges. Swim trials were done over the course of the exposure and each one consisted of an initial swim to 85% of the U{sub crit} of control fish, a 30 min recovery period and finally a second swim challenge to determine U{sub crit}. Plasma and tissue samples were collected before and after each of the swim periods. As expected from previous studies, Cd exposure resulted in significant accumulation of Cd in gills, liver and kidney but not in white muscle. Exposure also induced a loss of plasma Ca followed by subsequent recovery (in lake whitefish but not brown trout) with few mortalities (100% survival for lake whitefish and 93% for brown trout). Both control and exposed fish swam to 85% of the single swim U{sub crit} and no differences in performance were seen. The Ucrit of unexposed controls in the second swim challenges were not different from the single swim Ucrit. However, second swim performance was significantly reduced in Cd exposed fish, particularly after a week of exposure

  6. The effects of chronic cadmium exposure on repeat swimming performance and anaerobic metabolism in brown trout (Salmo trutta) and lake whitefish (Coregonus clupeaformis)

    International Nuclear Information System (INIS)

    Cunningham, Jessie L.; McGeer, James C.

    2016-01-01

    Highlights: • Exposure to 18 nM waterborne Cd induced plasma Ca loss that recovered by day 30 for lake whitefish but not brown trout. • Ucrit measured after an initial swim to 85% of Ucrit and a 30 min rest period was reduced in 18 nM Cd exposed fish compared to controls. • Swimming to 85% of Ucrit resulted in decreased muscle glycogen and increased lactate that was not recovered in the 30 min recovery period. • Second swim impairment is not related to metabolic processes in white muscle. - Abstract: This study investigates the effect of chronic Cd exposure on the ability to perform repeat swim challenges in brown trout (Salmo trutta) and lake whitefish (Coregonus clupeaformis). Fish were exposed to waterborne Cd (18 nM) in moderately hard water (120 mg L"−"1 CaCO_3) for 30 days. This level of exposure has been shown to cause sublethal physiological disruption and acclimation responses but no impairment of sustained swimming capacity (U_c_r_i_t) in single swim challenges. Swim trials were done over the course of the exposure and each one consisted of an initial swim to 85% of the U_c_r_i_t of control fish, a 30 min recovery period and finally a second swim challenge to determine U_c_r_i_t. Plasma and tissue samples were collected before and after each of the swim periods. As expected from previous studies, Cd exposure resulted in significant accumulation of Cd in gills, liver and kidney but not in white muscle. Exposure also induced a loss of plasma Ca followed by subsequent recovery (in lake whitefish but not brown trout) with few mortalities (100% survival for lake whitefish and 93% for brown trout). Both control and exposed fish swam to 85% of the single swim U_c_r_i_t and no differences in performance were seen. The Ucrit of unexposed controls in the second swim challenges were not different from the single swim Ucrit. However, second swim performance was significantly reduced in Cd exposed fish, particularly after a week of exposure where 31% and 38

  7. Dermal damage promoted by repeated low-level UV-A1 exposure despite tanning response in human skin.

    Science.gov (United States)

    Wang, Frank; Smith, Noah R; Tran, Bao Anh Patrick; Kang, Sewon; Voorhees, John J; Fisher, Gary J

    2014-04-01

    Solar UV irradiation causes photoaging, characterized by fragmentation and reduced production of type I collagen fibrils that provide strength to skin. Exposure to UV-B irradiation (280-320 nm) causes these changes by inducing matrix metalloproteinase 1 and suppressing type I collagen synthesis. The role of UV-A irradiation (320-400 nm) in promoting similar molecular alterations is less clear yet important to consider because it is 10 to 100 times more abundant in natural sunlight than UV-B irradiation and penetrates deeper into the dermis than UV-B irradiation. Most (approximately 75%) of solar UV-A irradiation is composed of UV-A1 irradiation (340-400 nm), which is also the primary component of tanning beds. To evaluate the effects of low levels of UV-A1 irradiation, as might be encountered in daily life, on expression of matrix metalloproteinase 1 and type I procollagen (the precursor of type I collagen). In vivo biochemical analyses were conducted after UV-A1 irradiation of normal human skin at an academic referral center. Participants included 22 healthy individuals without skin disease. Skin pigmentation was measured by a color meter (chromometer) under the L* variable (luminescence), which ranges from 0 (black) to 100 (white). Gene expression in skin samples was assessed by real-time polymerase chain reaction. Lightly pigmented human skin (L* >65) was exposed up to 4 times (1 exposure/d) to UV-A1 irradiation at a low dose (20 J/cm2), mimicking UV-A levels from strong sun exposure lasting approximately 2 hours. A single exposure to low-dose UV-A1 irradiation darkened skin slightly and did not alter matrix metalloproteinase 1 or type I procollagen gene expression. With repeated low-dose UV-A1 irradiation, skin darkened incrementally with each exposure. Despite this darkening, 2 or more exposures to low-dose UV-A1 irradiation significantly induced matrix metalloproteinase 1 gene expression, which increased progressively with successive exposures. Repeated UV-A1

  8. Amiodarone biokinetics, the formation of its major oxidative metabolite and neurotoxicity after acute and repeated exposure of brain cell cultures.

    Science.gov (United States)

    Pomponio, Giuliana; Zurich, Marie-Gabrielle; Schultz, Luise; Weiss, Dieter G; Romanelli, Luca; Gramowski-Voss, Alexandra; Di Consiglio, Emma; Testai, Emanuela

    2015-12-25

    The difficulty in mimicking nervous system complexity and cell-cell interactions as well as the lack of kinetics information has limited the use of in vitro neurotoxicity data. Here, we assessed the biokinetic profile as well as the neurotoxicity of Amiodarone after acute and repeated exposure in two advanced rodent brain cell culture models, consisting of both neurons and glial cells organized in 2 or 3 dimensions to mimic the brain histiotypic structure and function. A strategy was applied to evidence the abiotic processes possibly affecting Amiodarone in vitro bioavailability, showing its ability to adsorb to the plastic devices. At clinically relevant Amiodarone concentrations, known to induce neurotoxicity in some patients during therapeutic treatment, a complete uptake was observed in both models in 24 h, after single exposure. After repeated treatments, bioaccumulation was observed, especially in the 3D cell model, together with a greater alteration of neurotoxicity markers. After 14 days, Amiodarone major oxidative metabolite (mono-N-desethylamiodarone) was detected at limited levels, indicating the presence of active drug metabolism enzymes (i.e. cytochrome P450) in both models. The assessment of biokinetics provides useful information on the relevance of in vitro toxicity data and should be considered in the design of an Integrated Testing Strategy aimed to identify specific neurotoxic alerts, and to improve the neurotoxicity assay predictivity for human acute and repeated exposure. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Previous Repeated Exposure to Food Limitation Enables Rats to Spare Lipid Stores during Prolonged Starvation.

    Science.gov (United States)

    McCue, Marshall D; Albach, Audrey; Salazar, Giovanni

    The risk of food limitation and, ultimately, starvation dates back to the dawn of heterotrophy in animals, yet starvation remains a major factor in the regulation of modern animal populations. Researchers studying starvation more than a century ago suggested that animals subjected to sublethal periods of food limitation are somehow more tolerant of subsequent starvation events. This possibility has received little attention over the past decades, yet it is highly relevant to modern science for two reasons. First, animals in natural populations are likely to be exposed to bouts of food limitation once or more before they face prolonged starvation, during which the risk of mortality becomes imminent. Second, our current approach to studying starvation physiology in the laboratory focuses on nourished animals with no previous exposure to nutritional stress. We examined the relationship between previous exposure to food limitation and potentially adaptive physiological responses to starvation in adult rats and found several significant differences. On two occasions, rats were fasted until they lost 20% of their body mass maintained lower body temperatures, and had presumably lower energy requirements when subjected to prolonged starvation than their naive cohort that never experienced food limitation. These rats that were trained in starvation also had lower plasma glucose set -points and reduced their reliance on endogenous lipid oxidation. These findings underscore (1) the need for biologists to revisit the classic hypothesis that animals can become habituated to starvation, using a modern set of research tools; and (2) the need to design controlled experiments of starvation physiology that more closely resemble the dynamic nature of food availability.

  10. Cumulative effects of repeated exposure to pO2 = 200 kPa (2 atm).

    Science.gov (United States)

    Shykoff, Barbara E

    2014-01-01

    Even asymptomatic exposures to elevated oxygen partial pressure (pO2) can influence subsequent exposures. Dry chamber dives of three hours' duration at pO2 of 200 kPa were conducted to examine cumulative effects. Experiments were single (n = 27), or paired exposures with surface intervals (SIs) 15 to 17 hours (n = 30), six hours (n = 33), or three hours (n = 36). Flow-volume loops, diffusing capacity, and symptoms were recorded before and after exposures. Immediately after surfacing from second exposures, some significant (p < 0.05) mean changes from baseline in pulmonary function indices occurred for all SIs and persisted for two days for three-hour SIs and for one day for 15-hour SIs. Incidences of symptoms were 15% immediately after one exposure and 28%, 38% and 31% immediately after a second exposure following 15-, six- , or three-hour SIs, respectively. Incidences of changes in pulmonary function indices (deltaPF) were 5%, 11%, 12% and 14% for single exposures or two with 15-, six-, or three-hour SIs, respectively. Two days following the second exposure, resolution of symptoms was incomplete after six- or 15-hour SIs, as was resolution of deltaPF after 15-hour SIs. The incidences indicate non-linear superposition of effects of a first and second exposure, and are not readily explained by delayed-onset injury.

  11. Hearing loss associated with repeated MRI acquisition procedure-related acoustic noise exposure: an occupational cohort study.

    Science.gov (United States)

    Bongers, Suzan; Slottje, Pauline; Kromhout, Hans

    2017-11-01

    To study the effects of repeated exposure to MRI-related acoustic noise during image acquisition procedures (scans) on hearing. A retrospective occupational cohort study was performed among workers of an MRI manufacturing facility (n=474). Longitudinal audiometry data from the facility's medical surveillance scheme collected from 1973 to 2010 were analysed by studying the association of cumulative exposure to MRI-related acoustic noise from voluntary (multiple) MRI scans and the hearing threshold of the volunteer. Repeated acoustic noise exposure during volunteer MRI scans was found to be associated with a small exposure-dependent increased rate change of hearing threshold level (dB/year), but the association was only found related to the number of voluntary MRI scans and not to modelled cumulative noise exposure (dB*hour) based on MRI-system type. The increased rate change of hearing threshold level was found to be statistically significant for the frequencies 500, 1000, 2000, 3000 and 4000 Hz in the right ear. From our longitudinal cohort study, it appeared that exposure to noise from voluntarily MRI scans may have resulted in a slight amount of hearing loss. Mandatory use of hearing protection might have prevented more severe hearing loss. Lack of consistency in findings between the left and right ears and between the two exposure measures prohibits definitive conclusions. Further research that addresses the study's methodological limitations is warranted to corroborate our findings. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  12. Repeatability of grasp recognition for robotic hand prosthesis control based on sEMG data.

    Science.gov (United States)

    Palermo, Francesca; Cognolato, Matteo; Gijsberts, Arjan; Muller, Henning; Caputo, Barbara; Atzori, Manfredo

    2017-07-01

    Control methods based on sEMG obtained promising results for hand prosthetics. Control system robustness is still often inadequate and does not allow the amputees to perform a large number of movements useful for everyday life. Only few studies analyzed the repeatability of sEMG classification of hand grasps. The main goals of this paper are to explore repeatability in sEMG data and to release a repeatability database with the recorded experiments. The data are recorded from 10 intact subjects repeating 7 grasps 12 times, twice a day for 5 days. The data are publicly available on the Ninapro web page. The analysis for the repeatability is based on the comparison of movement classification accuracy in several data acquisitions and for different subjects. The analysis is performed using mean absolute value and waveform length features and a Random Forest classifier. The accuracy obtained by training and testing on acquisitions at different times is on average 27.03% lower than training and testing on the same acquisition. The results obtained by training and testing on different acquisitions suggest that previous acquisitions can be used to train the classification algorithms. The inter-subject variability is remarkable, suggesting that specific characteristics of the subjects can affect repeatibility and sEMG classification accuracy. In conclusion, the results of this paper can contribute to develop more robust control systems for hand prostheses, while the presented data allows researchers to test repeatability in further analyses.

  13. No impact of repeated extinction exposures on operant responding maintained by different reinforcer rates.

    Science.gov (United States)

    Bai, John Y H; Podlesnik, Christopher A

    2017-05-01

    Greater rates of intermittent reinforcement in the presence of discriminative stimuli generally produce greater resistance to extinction, consistent with predictions of behavioral momentum theory. Other studies reveal more rapid extinction with higher rates of reinforcers - the partial reinforcement extinction effect. Further, repeated extinction often produces more rapid decreases in operant responding due to learning a discrimination between training and extinction contingencies. The present study examined extinction repeatedly with training with different rates of intermittent reinforcement in a multiple schedule. We assessed whether repeated extinction would reverse the pattern of greater resistance to extinction with greater reinforcer rates. Counter to this prediction, resistance to extinction was consistently greater across twelve assessments of training followed by six successive sessions of extinction. Moreover, patterns of responding during extinction resembled those observed during satiation tests, which should not alter discrimination processes with repeated testing. These findings join others suggesting operant responding in extinction can be durable across repeated tests. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. The effects of chronic cadmium exposure on repeat swimming performance and anaerobic metabolism in brown trout (Salmo trutta) and lake whitefish (Coregonus clupeaformis).

    Science.gov (United States)

    Cunningham, Jessie L; McGeer, James C

    2016-04-01

    This study investigates the effect of chronic Cd exposure on the ability to perform repeat swim challenges in brown trout (Salmo trutta) and lake whitefish (Coregonus clupeaformis). Fish were exposed to waterborne Cd (18nM) in moderately hard water (120mgL(-1) CaCO3) for 30 days. This level of exposure has been shown to cause sublethal physiological disruption and acclimation responses but no impairment of sustained swimming capacity (Ucrit) in single swim challenges. Swim trials were done over the course of the exposure and each one consisted of an initial swim to 85% of the Ucrit of control fish, a 30min recovery period and finally a second swim challenge to determine Ucrit. Plasma and tissue samples were collected before and after each of the swim periods. As expected from previous studies, Cd exposure resulted in significant accumulation of Cd in gills, liver and kidney but not in white muscle. Exposure also induced a loss of plasma Ca followed by subsequent recovery (in lake whitefish but not brown trout) with few mortalities (100% survival for lake whitefish and 93% for brown trout). Both control and exposed fish swam to 85% of the single swim Ucrit and no differences in performance were seen. The Ucrit of unexposed controls in the second swim challenges were not different from the single swim Ucrit. However, second swim performance was significantly reduced in Cd exposed fish, particularly after a week of exposure where 31% and 38% reductions were observed for brown trout and lake whitefish respectively. Swimming to 85% Ucrit resulted in metabolic expenditure with little recovery after 30min. Few differences were observed between control and Cd exposed fish with the exception of a reduction in resting white muscle ATP stores of Cd exposed fish after 1 week of exposure. The results show that chronic sublethal Cd exposure results in an impairment of swimming ability in repeat swim challenges but this impairment is generally not related to metabolic processes

  15. Perspectives on repeated low-level blast and the measurement of neurotrauma in humans as an occupational exposure risk

    Science.gov (United States)

    Carr, W.; Dell, K. C.; Yanagi, M. A.; Hassan, D. M.; LoPresti, M. L.

    2017-11-01

    A pressing question in military medical research is the nature and degree of effects on the human brain from occupational repeated exposure to low-level explosive blast, but reliable and effective means to objectively measure such effects remain elusive. In survey results, headache, difficulty sleeping, irritability, cognitive impairment, and a variety of other symptoms consistent with post-concussive syndrome have been reported by those exposed to blast and there was positive correlation between degree of blast exposure and degree of symptomology, but an important goal is to obtain more objective evidence of an effect than self-report alone. This review reflects recent efforts to measure and evaluate such hypothesized effects and current recommendations for ongoing study. Optimal measures are likely those with sensitivity and specificity to systemic effects in mild neurotrauma, that have minimal to no volitional component, and that can be sampled relatively quickly with minimal intrusion in prospective, observational field studies during routine training with explosives. An understanding of an association between parameters of exposure to repeated low-level blast and negative neurologic effects would support the evaluation of clinical implications and development of protective equipment and surveillance protocols where warranted. At present, low-level blast exposure surveillance measurements do not exist as a systematic record for any professional community.

  16. Effects of repeated exposure to malathion on growth, food consumption, and locomotor performance of the western fence lizard (Sceloporus occidentalis)

    Energy Technology Data Exchange (ETDEWEB)

    Holem, Ryan R. [University of Georgia, Savannah River Ecology Laboratory, Aiken, SC 29801 (United States); ENTRIX, Inc., Okemos, MI 48864 (United States); Hopkins, William A. [University of Georgia, Savannah River Ecology Laboratory, Aiken, SC 29801 (United States); Department of Fisheries and Wildlife Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061 (United States)], E-mail: hopkinsw@vt.edu; Talent, Larry G. [Natural Resource Ecology and Management, Oklahoma State University, Stillwater, OK 74078 (United States)

    2008-03-15

    Effects of repeated pollutant exposure on growth, locomotor performance, and behavior have rarely been evaluated in reptiles. We administered three doses of malathion (2.0, 20, or 100 mg/kg body weight) to western fence lizards (Sceloporus occidentalis) over an 81 day period. Eight and 23% mortality occurred at 20 and 100 mg/kg (p = 0.079) and 85% of lizards in the 100 mg/kg group exhibited clinical symptoms of poisoning. Growth, food consumption, body condition index, and terrestrial locomotor performance were not significantly influenced by malathion. However, arboreal sprint velocity was significantly reduced in lizards receiving 100 mg/kg. Fifty percent of lizards in the 100 mg/kg group also refused to sprint in the arboreal setting (p = 0.085). Based on these results, arboreal locomotor performance was the most sensitive metric of exposure we evaluated. Further study of compounds such as malathion is warranted due to highly variable application rates and exposure scenarios. - Repeated exposure of western fence lizards to malathion caused reduced arboreal performance and some mortality but growth, food consumption, and terrestrial performance were not affected.

  17. Effects of repeated exposure to malathion on growth, food consumption, and locomotor performance of the western fence lizard (Sceloporus occidentalis)

    International Nuclear Information System (INIS)

    Holem, Ryan R.; Hopkins, William A.; Talent, Larry G.

    2008-01-01

    Effects of repeated pollutant exposure on growth, locomotor performance, and behavior have rarely been evaluated in reptiles. We administered three doses of malathion (2.0, 20, or 100 mg/kg body weight) to western fence lizards (Sceloporus occidentalis) over an 81 day period. Eight and 23% mortality occurred at 20 and 100 mg/kg (p = 0.079) and 85% of lizards in the 100 mg/kg group exhibited clinical symptoms of poisoning. Growth, food consumption, body condition index, and terrestrial locomotor performance were not significantly influenced by malathion. However, arboreal sprint velocity was significantly reduced in lizards receiving 100 mg/kg. Fifty percent of lizards in the 100 mg/kg group also refused to sprint in the arboreal setting (p = 0.085). Based on these results, arboreal locomotor performance was the most sensitive metric of exposure we evaluated. Further study of compounds such as malathion is warranted due to highly variable application rates and exposure scenarios. - Repeated exposure of western fence lizards to malathion caused reduced arboreal performance and some mortality but growth, food consumption, and terrestrial performance were not affected

  18. Secondhand tobacco smoke exposure and heart rate variability and inflammation among non-smoking construction workers: a repeated measures study.

    Science.gov (United States)

    Zhang, Jinming; Fang, Shona C; Mittleman, Murray A; Christiani, David C; Cavallari, Jennifer M

    2013-10-02

    Although it has been well recognized that exposure to secondhand tobacco smoke (SHS) is associated with cardiovascular mortality, the mechanisms and time course by which SHS exposure may lead to cardiovascular effects are still being explored. Non-smoking workers were recruited from a local union and monitored inside a union hall while exposed to SHS over approximately 6 hours. Participants were fitted with a continuous electrocardiographic monitor upon enrollment which was removed at the end of a 24-hr monitoring period. A repeated measures study design was used where resting ECGs and blood samples were taken from individuals before SHS exposure (baseline), immediately following SHS exposure (post) and the morning following SHS exposure (next-morning).Inflammatory markers, including high sensitivity C-reactive protein (CRP) and white blood cell count (WBC) were analyzed. Heart rate variability (HRV) was analyzed from the ECG recordings in time (SDNN, rMSSD) and frequency (LF, HF) domain parameters over 5-minute periods. SHS exposure was quantified using a personal fine particulate matter (PM2.5) monitor.Linear mixed effects regression models were used to examine within-person changes in inflammatory and HRV parameters across the 3 time periods. Exposure-response relationships with PM2.5 were examined using mixed effects models. All models were adjusted for age, BMI and circadian variation. A total of 32 male non-smokers were monitored between June 2010 and June 2012. The mean PM2.5 from SHS exposure was 132 μg/m3. Immediately following SHS exposure, a 100 μg/m3 increase in PM2.5 was associated with declines in HRV (7.8% [standard error (SE) =3%] SDNN, 8.0% (SE = 3.9%) rMSSD, 17.2% (SE = 6.3%) LF, 29.0% (SE = 10.1%) HF) and increases in WBC count 0.42 (SE = 0.14) k/μl. Eighteen hours following SHS exposure, a 100 μg/m3 increase in PM2.5 was associated with 24.2% higher CRP levels. Our study suggest that short-term SHS exposure is associated

  19. Effects of acute versus repeated cocaine exposure on the expression of endocannabinoid signaling-related proteins in the mouse cerebellum

    Directory of Open Access Journals (Sweden)

    Ana ePalomino

    2014-03-01

    Full Text Available Growing awareness of cerebellar involvement in addiction is based on the cerebellum’s intermediary position between motor and reward, potentially acting as an interface between motivational and cognitive functions. Here, we examined the impact of acute and repeated cocaine exposure on the two main signaling systems in the mouse cerebellum: the endocannabinoid (eCB and glutamate systems. To this end, we investigated whether eCB signaling-related gene and protein expression (CB1 receptors and enzymes that produce (DAGLα/β and NAPE-PLD and degrade (MAGL and FAAH eCB were altered. In addition, we analyzed the gene expression of relevant components of the glutamate signaling system (glutamate synthesizing enzymes LGA and KGA, mGluR3/5 metabotropic receptors, and NR1/2A/2B/2C-NMDA and GluR1/2/3/4-AMPA ionotropic receptor subunits and the gene expression of tyrosine hydroxylase (TH, the rate-limiting enzyme in catecholamine biosynthesis, because noradrenergic terminals innervate the cerebellar cortex. Results indicated that acute cocaine exposure decreased DAGLα expression, suggesting a down-regulation of 2-AG production, as well as gene expression of TH, KGA, mGluR3 and all ionotropic receptor subunits analyzed in the cerebellum. The acquisition of conditioned locomotion and sensitization after repeated cocaine exposure were associated with an increased NAPE-PLD/FAAH ratio, suggesting enhanced anandamide production, and a decreased DAGLβ/MAGL ratio, suggesting decreased 2-AG generation. Repeated cocaine also increased LGA gene expression but had no effect on glutamate receptors. These findings indicate that acute cocaine modulates the expression of the eCB and glutamate systems. Repeated cocaine results in normalization of glutamate receptor expression, although sustained changes in eCB is observed. We suggest that cocaine-induced alterations to cerebellar eCB should be considered when analyzing the adaptations imposed by psychostimulants that

  20. Tualang Honey Protects the Rat Midbrain and Lung against Repeated Paraquat Exposure

    Directory of Open Access Journals (Sweden)

    Suk Peng Tang

    2017-01-01

    Full Text Available Paraquat (PQ is a dopaminergic neurotoxin and a well-known pneumotoxicant that exerts its toxic effect via oxidative stress-mediated cellular injuries. This study investigated the protective effects of Tualang honey against PQ-induced toxicity in the midbrain and lungs of rats. The rats were orally treated with distilled water (2 mL/kg/day, Tualang honey (1.0 g/kg/day, or ubiquinol (0.2 g/kg/day throughout the experimental period. Two weeks after the respective treatments, the rats were injected intraperitoneally with saline (1 mL/kg/week or PQ (10 mg/kg/week once per week for four consecutive weeks. After four weekly exposures to PQ, the glutathione peroxidase activity and the number of tyrosine-hydroxylase immunopositive neurons in the midbrain were significantly decreased in animals from group PQ (p<0.05. The lungs of animals from group PQ showed significantly decreased activity of superoxide dismutase and glutathione-S-transferase. Treatment with Tualang honey ameliorated the toxic effects observed in the midbrain and lungs. The beneficial effects of Tualang honey were comparable to those of ubiquinol, which was used as a positive control. These findings suggest that treatment with Tualang honey may protect against PQ-induced toxicity in the rat midbrain and lung.

  1. Tualang Honey Protects the Rat Midbrain and Lung against Repeated Paraquat Exposure.

    Science.gov (United States)

    Tang, Suk Peng; Kuttulebbai Nainamohamed Salam, Sirajudeen; Jaafar, Hasnan; Gan, Siew Hua; Muzaimi, Mustapha; Sulaiman, Siti Amrah

    2017-01-01

    Paraquat (PQ) is a dopaminergic neurotoxin and a well-known pneumotoxicant that exerts its toxic effect via oxidative stress-mediated cellular injuries. This study investigated the protective effects of Tualang honey against PQ-induced toxicity in the midbrain and lungs of rats. The rats were orally treated with distilled water (2 mL/kg/day), Tualang honey (1.0 g/kg/day), or ubiquinol (0.2 g/kg/day) throughout the experimental period. Two weeks after the respective treatments, the rats were injected intraperitoneally with saline (1 mL/kg/week) or PQ (10 mg/kg/week) once per week for four consecutive weeks. After four weekly exposures to PQ, the glutathione peroxidase activity and the number of tyrosine-hydroxylase immunopositive neurons in the midbrain were significantly decreased in animals from group PQ ( p honey ameliorated the toxic effects observed in the midbrain and lungs. The beneficial effects of Tualang honey were comparable to those of ubiquinol, which was used as a positive control. These findings suggest that treatment with Tualang honey may protect against PQ-induced toxicity in the rat midbrain and lung.

  2. Tualang Honey Protects the Rat Midbrain and Lung against Repeated Paraquat Exposure

    Science.gov (United States)

    Sulaiman, Siti Amrah

    2017-01-01

    Paraquat (PQ) is a dopaminergic neurotoxin and a well-known pneumotoxicant that exerts its toxic effect via oxidative stress-mediated cellular injuries. This study investigated the protective effects of Tualang honey against PQ-induced toxicity in the midbrain and lungs of rats. The rats were orally treated with distilled water (2 mL/kg/day), Tualang honey (1.0 g/kg/day), or ubiquinol (0.2 g/kg/day) throughout the experimental period. Two weeks after the respective treatments, the rats were injected intraperitoneally with saline (1 mL/kg/week) or PQ (10 mg/kg/week) once per week for four consecutive weeks. After four weekly exposures to PQ, the glutathione peroxidase activity and the number of tyrosine-hydroxylase immunopositive neurons in the midbrain were significantly decreased in animals from group PQ (p honey ameliorated the toxic effects observed in the midbrain and lungs. The beneficial effects of Tualang honey were comparable to those of ubiquinol, which was used as a positive control. These findings suggest that treatment with Tualang honey may protect against PQ-induced toxicity in the rat midbrain and lung. PMID:28127418

  3. Repeated CT scans in trauma transfers: An analysis of indications, radiation dose exposure, and costs

    International Nuclear Information System (INIS)

    Hinzpeter, Ricarda; Sprengel, Kai; Wanner, Guido A.; Mildenberger, Peter; Alkadhi, Hatem

    2017-01-01

    Highlights: • Repetition of CT in trauma patients occurs relatively often. • Repetition of CT is mainly caused by inadequate image data transfer. • Potentially preventable CT examinations add radiation dose to patients. • Repeated CT is associated with excess costs to the health care system. - Abstract: Objectives: To identify the number of CT scans repeated in acute trauma patients receiving imaging before being referred to a trauma center, to define indications, and to assess radiation doses and costs of repeated CT. Methods: This retrospective study included all adult trauma patients transferred from other hospitals to a Level-I trauma center during 2014. Indications for repeated CT scans were categorized into: inadequate CT image data transfer, poor image quality, repetition of head CT after head injury together with completion to whole-body CT (WBCT), and follow-up of injury known from previous CT. Radiation doses from repeated CT were determined; costs were calculated using a nation-wide fee schedule. Results: Within one year, 85/298 (28.5%) trauma patients were transferred from another hospital because of severe head injury (n = 45,53%) and major body trauma (n = 23;27%) not manageable in the referring hospital, repatriation from a foreign country (n = 14;16.5%), and no ICU-capacity (n = 3;3.5%). Of these 85 patients, 74 (87%) had repeated CT in our center because of inadequate CT data transfer (n = 29;39%), repetition of head CT with completion to WBCT (n = 24;32.5%), and follow-up of known injury (n = 21;28.5%). None occurred because of poor image quality. Cumulative dose length product (DLP) and annual costs of potential preventable, repeated CT (inadequate data transfer) was 631mSv (81′304mGy*cm) and 35′233€, respectively. Conclusion: A considerable number of transferred trauma patients undergo potentially preventable, repeated CT, adding radiation dose to patients and costs to the health care system.

  4. Repeated CT scans in trauma transfers: An analysis of indications, radiation dose exposure, and costs

    Energy Technology Data Exchange (ETDEWEB)

    Hinzpeter, Ricarda, E-mail: Ricarda.Hinzpeter@usz.ch [Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, University of Zurich, Raemistr. 100, Zurich CH-8091 (Switzerland); Sprengel, Kai, E-mail: Kai.Sprengel@usz.ch [Division of Trauma Surgery, Department of Surgery, University Hospital Zurich, University of Zurich, Raemistr. 100, CH-8091 Zurich (Switzerland); Wanner, Guido A., E-mail: Guido.Wanner@sbk-vs.de [Division of Trauma Surgery, Department of Surgery, University Hospital Zurich, University of Zurich, Raemistr. 100, CH-8091 Zurich (Switzerland); Department of General Surgery, Schwarzwald-Baar Klinikum, University of Freiburg, Klinikstr. 11, D-78052 Villingen-Schwenningen (Germany); Mildenberger, Peter, E-mail: peter.mildenberger@unimedizin-mainz.de [Department of Diagnostic and Interventional Radiology, University Hospital of Mainz, Langenbeckstr. 1, D-55131 Mainz (Germany); Alkadhi, Hatem, E-mail: hatem.alkadhi@usz.ch [Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, University of Zurich, Raemistr. 100, Zurich CH-8091 (Switzerland)

    2017-03-15

    Highlights: • Repetition of CT in trauma patients occurs relatively often. • Repetition of CT is mainly caused by inadequate image data transfer. • Potentially preventable CT examinations add radiation dose to patients. • Repeated CT is associated with excess costs to the health care system. - Abstract: Objectives: To identify the number of CT scans repeated in acute trauma patients receiving imaging before being referred to a trauma center, to define indications, and to assess radiation doses and costs of repeated CT. Methods: This retrospective study included all adult trauma patients transferred from other hospitals to a Level-I trauma center during 2014. Indications for repeated CT scans were categorized into: inadequate CT image data transfer, poor image quality, repetition of head CT after head injury together with completion to whole-body CT (WBCT), and follow-up of injury known from previous CT. Radiation doses from repeated CT were determined; costs were calculated using a nation-wide fee schedule. Results: Within one year, 85/298 (28.5%) trauma patients were transferred from another hospital because of severe head injury (n = 45,53%) and major body trauma (n = 23;27%) not manageable in the referring hospital, repatriation from a foreign country (n = 14;16.5%), and no ICU-capacity (n = 3;3.5%). Of these 85 patients, 74 (87%) had repeated CT in our center because of inadequate CT data transfer (n = 29;39%), repetition of head CT with completion to WBCT (n = 24;32.5%), and follow-up of known injury (n = 21;28.5%). None occurred because of poor image quality. Cumulative dose length product (DLP) and annual costs of potential preventable, repeated CT (inadequate data transfer) was 631mSv (81′304mGy*cm) and 35′233€, respectively. Conclusion: A considerable number of transferred trauma patients undergo potentially preventable, repeated CT, adding radiation dose to patients and costs to the health care system.

  5. Effect of exposure to evening light on sleep initiation in the elderly: a longitudinal analysis for repeated measurements in home settings.

    Science.gov (United States)

    Obayashi, Kenji; Saeki, Keigo; Iwamoto, Junko; Okamoto, Nozomi; Tomioka, Kimiko; Nezu, Satoko; Ikada, Yoshito; Kurumatani, Norio

    2014-05-01

    Epidemiologic data have demonstrated associations of sleep-onset insomnia with a variety of diseases, including depression, dementia, diabetes and cardiovascular diseases. Sleep initiation is controlled by the suprachiasmatic nucleus of the hypothalamus and endogenous melatonin, both of which are influenced by environmental light. Exposure to evening light is hypothesized to cause circadian phase delay and melatonin suppression before bedtime, resulting in circadian misalignment and sleep-onset insomnia; however, whether exposure to evening light disturbs sleep initiation in home settings remains unclear. In this longitudinal analysis of 192 elderly individuals (mean age: 69.9 years), we measured evening light exposure and sleep-onset latency for 4 days using a wrist actigraph incorporating a light meter and an accelerometer. Mixed-effect linear regression analysis for repeated measurements was used to evaluate the effect of evening light exposure on subsequent sleep-onset latency. The median intensity of evening light exposure and the median sleep-onset latency were 27.3 lux (interquartile range, 17.9-43.4) and 17 min (interquartile range, 7-33), respectively. Univariate models showed significant associations between sleep-onset latency and age, gender, daytime physical activity, in-bed time, day length and average intensity of evening and nighttime light exposures. In a multivariate model, log-transformed average intensity of evening light exposure was significantly associated with log-transformed sleep-onset latency independent of the former potential confounding factors (regression coefficient, 0.133; 95% CI, 0.020-0.247; p = 0.021). Day length and nighttime light exposure were also significantly associated with log-transformed sleep-onset latency (p = 0.001 and p < 0.001, respectively). In conclusion, exposure to evening light in home setting prolongs subsequent sleep-onset latency in the elderly.

  6. Repeated exposure to the thin ideal and implications for the self : Two weight loss program studies

    NARCIS (Netherlands)

    Klesse, A.K.; Goukens, C.; Geyskens, K.; de Ruyter, K.

    2012-01-01

    Exposure to thin models results in self-esteem shifts that influence people's motivation to diet. This research study applies a goal perspective to explain the effect of exposure to thin models on dieters' motivation to lose weight. Two (one-week) weight loss program studies that included treatment

  7. Repeated stress exposure causes strain-dependent shifts in the behavioral economics of cocaine in rats

    NARCIS (Netherlands)

    Groblewski, Peter A.; Zietz, Chad; Willuhn, Ingo; Phillips, Paul E. M.; Chavkin, Charles

    2015-01-01

    Cocaine-experienced Wistar and Wistar Kyoto (WKY) rats received four daily repeated forced swim stress sessions (R-FSS), each of which preceded 4-hour cocaine self-administration sessions. Twenty-four hours after the last swim stress, cocaine valuation was assessed during a single-session threshold

  8. Changes of lead speciation and microbial toxicity in soil treated with repeated Pb exposure in the presence of BDE209.

    Science.gov (United States)

    Zhang, Rong; Zhang, Wei; Liu, Gao; Lin, Kuangfei; Fu, Rongbing

    2016-03-01

    Lead (Pb) and decabromodiphenyl ether (BDE209) are main pollutants at electric waste (e-waste) recycling sites (EWRSs), and their joint toxicological effects have received extensive attention. Frequently, soil pollution at EWRSs usually results from the occurrence of repeated single or multiple pollution events, with continuous impacts on soil microorganisms. Therefore, a laboratory incubation study was conducted to determine Pb bioavailability and microbial toxicity in repeated Pb-polluted soil in the presence of BDE209 for the first time. We evaluated the impacts of repetitive exposure trials on chemical fractions of Pb, and the results showed that repeated single Pb pollution event resulted in an increase of carbonates fraction of Pb, which was different from one-off single Pb exposure. Moreover, one-off Pb-treated groups exhibited higher I R (reduced partition index) values on day 30 and all treatments remained the same I R level at the end of incubation period. The parameters of microbial toxicity were well reflected by soil enzymes. During the entire incubation, the dehydrogenase and urease activities were significantly inhibited by Pb (P soil enzymes were clearly observed (P < 0.05 or 0.01). Such observations would provide useful information for ecological effects of Pb and BDE209 at EWRSs.

  9. OSHA Bloodborne Pathogens Standards Exposure Control Plan

    Science.gov (United States)

    Luhrs, Caro Elise; Teitelbaum, Rita

    1993-01-01

    The Hummer Associates Exposure Control Plan is designed to reduce significant occupational exposure to bloodborne pathogens and infectious materials for Hummer Associates health care personnel. Under universal precautions, all patients and all body fluids are considered potentially infectious for bloodborne pathogens. Medical personnel need not be at increased risk if universal precautions are correctly understood and followed. This program covers all employees who could reasonably anticipate contact with blood or other potentially infectious materials during the performance of their job responsibilities. Although HIV and hepatitis B are mentioned most often, this program applies to all bloodborne diseases. The two main components needed to implement this program are universal precautions and engineering/work practice controls. This program covers all employees who may have occupational exposure to blood or other potentially infectious materials. Other aspects of this program are discussed.

  10. Repeated sublethal exposures to the sea lice pesticide Salmosan® (azamethiphos) on adult male lobsters (Homarus americanus) causes neuromuscular dysfunction, hypoxia, metabolic disturbances and mortality.

    Science.gov (United States)

    Dounia, Daoud; Andrea, Battison; Lefort, Natalie; Van Geest, Jordana Lynne

    2016-12-01

    In Atlantic Canada and other salmon-growing regions, treatment of sea lice infestations in salmon aquaculture is necessary to protect fish health. The product Salmosan®, which contains the organophosphate azamethiphos as the active ingredient, is a pesticide presently used for treatment against sea lice. It is applied as a bath treatment and then released into the surrounding seawater. The potential for lethality to non-target species following acute and chronic exposures to Salmosan® has been studied over the past decade, however, the potential for sublethal effects on lobsters remains a concern. Adult male lobsters were exposed to 0.06, 0.5, and 5µgL -1 azamethiphos for one hour, repeated five times, over 48h. Lobsters were assessed immediately after exposure and over six days of recovery. Inhibition of muscle cholinesterase activity was detected in lobsters exposed to 0.5 and 5µgL -1 azamethiphos. The 5µgL -1 dose was considered lethal (93% cumulative mortality). Significant changes in hemolymph plasma biochemistry were most apparent in the 5µgL -1 exposure group in the immediate post-exposure samples. Citrate synthase activity was significantly lower in muscles of the 0.5µgL -1 exposure group compared to control lobsters. Mean electron transport system and standard metabolic rates tended to be lower in muscle tissue of the 0.5µgL -1 exposure group than control group lobsters. These results suggest that sublethal effects on lobster energetics may occur under laboratory exposure conditions (i.e., concentrations and duration) considered environmentally relevant, which could result in impairment under natural conditions. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. Controlling exposure to radon, France, December 2006

    International Nuclear Information System (INIS)

    Godet, J.L.; Perrin, M.L.; Dechaux, E.; Pineau, C.

    2007-01-01

    Controlling exposure to radon, France, December 2006 Exposure to radon, along with medical exposure, is the leading source of the French population exposure to ionizing radiation. Radon is a confirmed cause of lung cancer in man (classified in group I by the international Agency for research on Cancer (I.A.R.C.)). According to available estimates, the numbers of lung cancers attributable to radon exposure in France are far fewer than those caused by tobacco. However, according to a recent European study, around 9% of lung cancers in Europe may be caused by radon. Thus, due to the number of people exposed, radon has become a public health issue which calls for action, considering that exposure can be significantly reduced by implementing measures which are often simple. Since 2002, the Nuclear Safety Authority (Asn) has proceeded in implementing a new regulatory framework for the risk management related to the presence of radon in public places. The new system is now fully operational. In addition, based on the initiatives adopted by the government in June 2004 in the context of the National Health and Environment Plan (P.N.S.E.), the Asn drew up a plan in 2005, in collaboration with the Ministry for Urban Planning and Construction, to coordinate the actions of various national bodies involved in this field. This three-pronged strategy is as follows: - Creation of a new risk management policy related to the presence of radon in existing homes and in new buildings; - Supporting and controlling the implementation of regulations for managing radon related risks in public places; - Improvement and dissemination of knowledge on radon exposure and its related risks. (author)

  12. Protective effect of curcumin on pulmonary and cardiovascular effects induced by repeated exposure to diesel exhaust particles in mice.

    Directory of Open Access Journals (Sweden)

    Abderrahim Nemmar

    Full Text Available Particulate air pollution has been associated with increased risk of cardiopulmonary diseases. However, the underlying mechanisms are not fully understood. We have previously demonstrated that single dose exposure to diesel exhaust particle (DEP causes lung inflammation and peripheral thrombotic events. Here, we exposed mice with repeated doses of DEP (15 µg/animal every 2(nd day for 6 days (a total of 4 exposures, and measured several cardiopulmonary endpoints 48 h after the end of the treatments. Moreover, the potential protective effect of curcumin (the yellow pigment isolated from turmeric on DEP-induced cardiopulmonary toxicity was assessed. DEP exposure increased macrophage and neutrophil numbers, tumor necrosis factor α (TNF α in the bronchoalveolar lavage (BAL fluid, and enhanced airway resistance to methacoline measured invasively using Flexivent. DEP also significantly increased plasma C-reactive protein (CRP and TNF α concentrations, systolic blood pressure (SBP as well as the pial arteriolar thrombosis. It also significantly enhanced the plasma D-dimer and plasminogen activator inhibitor-1 (PAI-1. Pretreatment with curcumin by oral gavage (45 mg/kg 1 h before exposure to DEP significantly prevented the influx of inflammatory cells and the increase of TNF α in BAL, and the increased airway resistance caused by DEP. Likewise, curcumin prevented the increase of SBP, CRP, TNF α, D-dimer and PAI-1. The thrombosis was partially but significantly mitigated. In conclusion, repeated exposure to DEP induced lung and systemic inflammation characterized by TNFα release, increased SBP, and accelerated coagulation. Our findings indicate that curcumin is a potent anti-inflammatory agent that prevents the release of TNFα and protects against the pulmonary and cardiovascular effects of DEP.

  13. Phasic Mesolimbic Dopamine Signaling Encodes the Facilitation of Incentive Motivation Produced by Repeated Cocaine Exposure

    OpenAIRE

    Ostlund, SB; LeBlanc, KH; Kosheleff, AR; Wassum, KM; Maidment, NT

    2014-01-01

    Drug addiction is marked by pathological drug seeking and intense drug craving, particularly in response to drug-related stimuli. Repeated psychostimulant administration is known to induce long-term alterations in mesolimbic dopamine (DA) signaling that are hypothesized to mediate this heightened sensitivity to environmental stimuli. However, there is little direct evidence that drug-induced alteration in mesolimbic DA function underlies this hypersensitivity to motivational cues. In the curr...

  14. Combined Study of Titanium Dioxide Nanoparticle Transport and Toxicity on Microbial Nitrifying Communities under Single and Repeated Exposures in Soil Columns.

    Science.gov (United States)

    Simonin, Marie; Martins, Jean M F; Uzu, Gaëlle; Vince, Erwann; Richaume, Agnès

    2016-10-04

    Soils are exposed to nanoparticles (NPs) as a result of their increasing use in many commercial products. Adverse effects of NPs on soil microorganisms have been reported in several ecotoxicological studies using microcosms. Although repeated exposures are more likely to occur in soils, most of these previous studies were performed as a single exposure to NPs. Contrary to single contamination, the study of multiple NP contaminations in soils requires the use of specialized setups. Using a soil column experiment, we compared the influence of single and repeated exposures (one, two, or three exposures that resulted in the same final concentration applied) on the transport of titanium dioxide (TiO 2 ) NPs through soil and the effect of these different exposure scenarios on the abundance and activity of soil nitrifying microbial communities after a 2 month incubation. The transport of TiO 2 NPs was very limited under both single and repeated exposures and was highest for the lowest concentration injected during the first application. Significant decreases in nitrification activity and ammonia-oxidizing archaea and bacteria populations were observed only for the repeated exposure scenario (three TiO 2 NP contaminations). These results suggest that, under repeated exposures, the transport of TiO 2 NPs to deep soil layers and groundwater is limited and that a chronic contamination is more harmful for the soil microbiological functioning than a single exposure.

  15. Distribution of dearomatised white spirit in brain, blood, and fat tissue after repeated exposure of rats

    DEFF Research Database (Denmark)

    Lof, A.; Lam, Henrik Rye; Gullstrand, E.

    1999-01-01

    Petroleum products with low content of aromatics have been increasingly used during the past years. This study investigates tissue disposition of dearomatised white spirit. In addition, brain neurotransmitter concentrations were measured. Male rats were exposed by inhalation to 0, 400 (2.29 mg....../l), or 800 p.p.m. (4.58 mg/l) of dearomatised white spirit, 6 hr/day, 5 days/week up to 3 weeks. Five rats from each group were sacrificed immediately after the exposure for 1, 2, or 3 weeks and 2, 4, 6, or 24 hr after the end of 3 weeks' exposure. After 3 weeks of exposure the concentration of total white...... spirit was 1.5 and 5.6 mg/kg in blood; 7.1 and 17.1 mg/kg in brain; 432 and 1452 mg/kg in fat tissue at the exposure levels of 400 and 800 p.p.m., respectively. The concentrations of n-nonane, n-decane, n-undecane, and total white spirit in blood and brain were not affected by the duration of exposure...

  16. Beyond Extinction: Prolonged Conditioning and Repeated Threat Exposure Abolish Contextual Renewal of Fear-Potentiated Startle Discrimination but Leave Expectancy Ratings Intact.

    Science.gov (United States)

    Leer, Arne; Haesen, Kim; Vervliet, Bram

    2018-01-01

    Extinction treatments decrease fear via repeated exposures to the conditioned stimulus (CS) and are associated with a return of fear. Alternatively, fear can be reduced via reductions in the perceived intensity of the unconditioned stimulus (US), e.g., through repeated exposures to the US. Promisingly, the few available studies show that repeated US exposures outperform standard extinction. US exposure treatments can decrease fear via two routes: (1) by weakening the CS-US association (extinction-like mechanism), and/or (2) by weakening the subjective US aversiveness (habituation-like mechanism). The current study further investigated the conditions under which US exposure treatment may reduce renewal, by adding a group in which CS-US pairings continued following fear acquisition. During acquisition, participants learned that one of two visual stimuli (CS+/CS-) predicted the occurrence of an aversive electrocutaneous stimulus (US). Next, the background context changed and participants received one of three interventions: repeated CS exposures, (2) repeated US exposures, or (3) continued CS-US pairings. Following repeated CS exposures, test presentations of the CSs in the original conditioning context revealed intact CS+/CS- differentiation in the fear-potentiated startle reflex, while the differentiation was abolished in the other two groups. Differential US expectancy ratings, on the other hand, were intact in all groups. Skin conductance data were inconclusive because standard context renewal following CS exposures did not occur. Unexpectedly, there was no evidence for a habituation-like process having taken place during US exposures or continued CS-US pairings. The results provide further evidence that US exposures outperform the standard extinction treatment and show that effects are similar when US exposures are part of CS-US pairings.

  17. Photoprotection due to pigmentation and epidermal thickness after repeated exposure to ultraviolet light and psoralen plus ultraviolet A therapy

    Energy Technology Data Exchange (ETDEWEB)

    Bech-Thomsen, N.; Wulf, H.C. [Rigshospitalet, The National Univ. Hospital, Dept. of Dermatology, Lab. of Photobiology, Copenhagen (Denmark)

    1995-10-01

    Tanning and thickening of the epidermis are cardinal defensive responses of human skin to ultraviolet (UV) radiation that lead to increased photoprotection. Earlier studies have shown that skin pigmentation can be used to predict minimal erythema dose and minimal phototoxic dose. In this study it was calculated how much of the increase in photoprotection after 4 weeks of repeated exposure to suberythemogenic doses of either UVA or UVB radiation sources or psoralen plus UVA (PUVA) therapy that was attributable to melanogenesis. The backs of 12 volunteers were exposed to 6 different UVA and UVB radiation sources 9 times during 4 weeks. Skin pigmentation was assessed by skin reflectance measuring. Photoprotection was determined from the minimal erythema dose. Melanogenesis accounted for 63-95% of the increase in photoprotection after 4 weeks of exposure to UVA radiation. Exposure to two UVB sources induced a significant increase in photoprotection but not in pigmentation. Melanogenesis accounted only for 6-11% of the increase in photoprotection after 4 weeks of UVB exposure. The pigmentary and photoprotective responses to PUVA therapy were followed in 14 patients. After 2 weeks of exposure, the increase in photoprotection was significantly higher than predicted form the increase in skin pigmentation. After 4 weeks, melanogenesis accounted for only 36% of the increase in photoprotection. This study shows that melanogenesis accounts for the increased photoprotection after 2 weeks of exposure to UVA radiation, but after 4 weeks other protective mechanisms occur during suberythemal UVB exposure and during PUVA therapy the importance of skin pigmentation in the overall photoprotection gradually decreases during a 4-week irradiation period. (au) 17 refs.

  18. Photoprotection due to pigmentation and epidermal thickness after repeated exposure to ultraviolet light and psoralen plus ultraviolet A therapy

    International Nuclear Information System (INIS)

    Bech-Thomsen, N.; Wulf, H.C.

    1995-01-01

    Tanning and thickening of the epidermis are cardinal defensive responses of human skin to ultraviolet (UV) radiation that lead to increased photoprotection. Earlier studies have shown that skin pigmentation can be used to predict minimal erythema dose and minimal phototoxic dose. In this study it was calculated how much of the increase in photoprotection after 4 weeks of repeated exposure to suberythemogenic doses of either UVA or UVB radiation sources or psoralen plus UVA (PUVA) therapy that was attributable to melanogenesis. The backs of 12 volunteers were exposed to 6 different UVA and UVB radiation sources 9 times during 4 weeks. Skin pigmentation was assessed by skin reflectance measuring. Photoprotection was determined from the minimal erythema dose. Melanogenesis accounted for 63-95% of the increase in photoprotection after 4 weeks of exposure to UVA radiation. Exposure to two UVB sources induced a significant increase in photoprotection but not in pigmentation. Melanogenesis accounted only for 6-11% of the increase in photoprotection after 4 weeks of UVB exposure. The pigmentary and photoprotective responses to PUVA therapy were followed in 14 patients. After 2 weeks of exposure, the increase in photoprotection was significantly higher than predicted form the increase in skin pigmentation. After 4 weeks, melanogenesis accounted for only 36% of the increase in photoprotection. This study shows that melanogenesis accounts for the increased photoprotection after 2 weeks of exposure to UVA radiation, but after 4 weeks other protective mechanisms occur during suberythemal UVB exposure and during PUVA therapy the importance of skin pigmentation in the overall photoprotection gradually decreases during a 4-week irradiation period. (au) 17 refs

  19. Distribution of silver in rats following 28 days of repeated oral exposure to silver nanoparticles or silver acetate

    DEFF Research Database (Denmark)

    Löschner, Katrin; Hadrup, Niels; Qvortrup, Klaus

    2011-01-01

    Background: The study investigated the distribution of silver after 28 days repeated oral administration of silver nanoparticles (AgNPs) and silver acetate (AgAc) to rats. Oral administration is a relevant route of exposure because of the use of silver nanoparticles in products related to food...... and food contact materials. Results: AgNPs were synthesized with a size distribution of 14 ± 4 nm in diameter (90% of the nanoparticle volume) and stabilized in aqueous suspension by the polymer polyvinylpyrrolidone (PVP). The AgNPs remained stable throughout the duration of the 28-day oral toxicity study...... in rats. The organ distribution pattern of silver following administration of AgNPs and AgAc was similar. However the absolute silver concentrations in tissues were lower following oral exposure to AgNPs. This was in agreement with an indication of a higher fecal excretion following administration of Ag...

  20. Effect of Acute, Subacute, and Repeated Exposure to High Altitude (5050 m on Psychomotor Vigilance

    Directory of Open Access Journals (Sweden)

    Matiram Pun

    2018-06-01

    Full Text Available Aim: High altitude (HA hypoxia may affect cognitive performance and sleep quality. Further, vigilance is reduced following sleep deprivation. We investigated the effect on vigilance, actigraphic sleep indices, and their relationships with acute mountain sickness (AMS during very HA exposure, acclimatization, and re-exposure.Methods: A total of 21 healthy altitude-naive individuals (25 ± 4 years; 13 females completed 2 cycles of altitude exposure separated by 7 days at low altitude (LA, 520 m. Participants slept at 2900 m and spent the day at HA, (5050 m. We report acute altitude exposure on Day 1 (LA vs. HA1 and after 6 days of acclimatization (HA1 vs. HA6. Vigilance was quantified by reaction speed in the 10-min psychomotor vigilance test reaction speed (PVT-RS. AMS was evaluated using the Environmental Symptoms Questionnaire Cerebral Score (AMS-C score. Nocturnal rest/activity was recorded to estimate sleep duration using actigraphy.Results: In Cycle 1, PVT-RS was slower at HA1 compared to LA (4.1 ± 0.8 vs. 4.5 ± 0.6 s-1, respectively, p = 0.029, but not at HA6 (4.6 ± 0.7; p > 0.05. In Cycle 2, PVT-RS at HA1 (4.6 ± 0.7 and HA6 (4.8 ± 0.6 were not different from LA (4.8 ± 0.6, p > 0.05 and significantly greater than corresponding values in Cycle 1. In both cycles, AMS scores were higher at HA1 than at LA and HA6 (p < 0.05. Estimated sleep durations (TST at LA, 1st and 5th nights were 431.3 ± 28.7, 418.1 ± 48.6, and 379.7 ± 51.4 min, respectively, in Cycle 1 and they were significantly reduced during acclimatization exposures (LA vs. 1st night, p > 0.05; LA vs. 5th night, p = 0.012; and 1st vs. 5th night, p = 0.054. LA, 1st and 5th nights TST in Cycle 2 were 477.5 ± 96.9, 430.9 ± 34, and 341.4 ± 32.2, respectively, and we observed similar deteriorations in TST as in Cycle 1 (LA vs. 1st night, p > 0.05; LA vs. 5th night, p = 0.001; and 1st vs. 5th night, p < 0.0001. At HA1, subjects who reported higher AMS-C scores exhibited slower

  1. Distinctive adaptive response to repeated exposure to hydrogen peroxide associated with upregulation of DNA repair genes and cell cycle arrest

    Directory of Open Access Journals (Sweden)

    Gloria A. Santa-Gonzalez

    2016-10-01

    Full Text Available Many environmental and physiological stresses are chronic. Thus, cells are constantly exposed to diverse types of genotoxic insults that challenge genome stability, including those that induce oxidative DNA damage. However, most in vitro studies that model cellular response to oxidative stressors employ short exposures and/or acute stress models. In this study, we tested the hypothesis that chronic and repeated exposure to a micromolar concentration of hydrogen peroxide (H2O2 could activate DNA damage responses, resulting in cellular adaptations. For this purpose, we developed an in vitro model in which we incubated mouse myoblast cells with a steady concentration of ~50 μM H2O2 for one hour daily for seven days, followed by a final challenge of a 10 or 20X higher dose of H2O2 (0.5 or 1 mM. We report that intermittent long-term exposure to this oxidative stimulus nearly eliminated cell toxicity and significantly decreased genotoxicity (in particular, a >5-fold decreased in double-strand breaks resulting from subsequent acute exposure to oxidative stress. This protection was associated with cell cycle arrest in G2/M and induction of expression of nine DNA repair genes. Together, this evidence supports an adaptive response to chronic, low-level oxidative stress that results in genomic protection and up-regulated maintenance of cellular homeostasis.

  2. Preventive effect of curcumin and its highly bioavailable preparation on hearing loss induced by single or repeated exposure to noise: A comparative and mechanistic study

    Directory of Open Access Journals (Sweden)

    Taro Yamaguchi

    2017-08-01

    Full Text Available We sought to determine the preventive effects of curcumin and its highly bioavailable preparation on noise-induced hearing loss in a novel murine model of permanent hearing loss developed by repeated exposure to noise. Upon exposure to noise (8-kHz octave band noise, 90 dB sound pressure level, 1 h, hearing ability was impaired in a temporary and reversible manner. During repeated noise exposure (1-h exposure per day, 5 days, there was a progressive increase in the auditory threshold shift at 12 and 20 kHz. The threshold shift persisted for at least 6 days after noise exposure. Oral administration of curcumin for 3 days before and each day during noise exposure significantly alleviated the hearing loss induced by repeated noise exposure. Curcumin abolished intranuclear translocation of nuclear factor-κB-p65 and generation of 4-hydroxynonenal-adducted proteins found in the cochlea after noise exposure. Theracurmin®, a highly absorbable and bioavailable preparation of curcumin, had strong preventive effects on hearing loss induced by repeated noise exposure. Together, these data suggest that curcumin exerts a preventive effect on noise-induced hearing loss and is therefore a good therapeutic candidate for preventing sensorineural hearing loss.

  3. Preventive effect of curcumin and its highly bioavailable preparation on hearing loss induced by single or repeated exposure to noise: A comparative and mechanistic study.

    Science.gov (United States)

    Yamaguchi, Taro; Yoneyama, Masanori; Onaka, Yusuke; Imaizumi, Atsushi; Ogita, Kiyokazu

    2017-08-01

    We sought to determine the preventive effects of curcumin and its highly bioavailable preparation on noise-induced hearing loss in a novel murine model of permanent hearing loss developed by repeated exposure to noise. Upon exposure to noise (8-kHz octave band noise, 90 dB sound pressure level, 1 h), hearing ability was impaired in a temporary and reversible manner. During repeated noise exposure (1-h exposure per day, 5 days), there was a progressive increase in the auditory threshold shift at 12 and 20 kHz. The threshold shift persisted for at least 6 days after noise exposure. Oral administration of curcumin for 3 days before and each day during noise exposure significantly alleviated the hearing loss induced by repeated noise exposure. Curcumin abolished intranuclear translocation of nuclear factor-κB-p65 and generation of 4-hydroxynonenal-adducted proteins found in the cochlea after noise exposure. Theracurmin ® , a highly absorbable and bioavailable preparation of curcumin, had strong preventive effects on hearing loss induced by repeated noise exposure. Together, these data suggest that curcumin exerts a preventive effect on noise-induced hearing loss and is therefore a good therapeutic candidate for preventing sensorineural hearing loss. Copyright © 2017 The Authors. Production and hosting by Elsevier B.V. All rights reserved.

  4. Tandemly repeated sequence in 5'end of mtDNA control region of ...

    African Journals Online (AJOL)

    Extensive length variability was observed in 5' end sequence of the mitochondrial DNA control region of the Japanese Spanish mackerel (Scomberomorus niphonius). This length variability was due to the presence of varying numbers of a 56-bp tandemly repeated sequence and a 46-bp insertion/deletion (indel).

  5. Driving simulator sickness: Impact on driving performance, influence of blood alcohol concentration, and effect of repeated simulator exposures.

    Science.gov (United States)

    Helland, Arne; Lydersen, Stian; Lervåg, Lone-Eirin; Jenssen, Gunnar D; Mørland, Jørg; Slørdal, Lars

    2016-09-01

    Simulator sickness is a major obstacle to the use of driving simulators for research, training and driver assessment purposes. The purpose of the present study was to investigate the possible influence of simulator sickness on driving performance measures such as standard deviation of lateral position (SDLP), and the effect of alcohol or repeated simulator exposure on the degree of simulator sickness. Twenty healthy male volunteers underwent three simulated driving trials of 1h's duration with a curvy rural road scenario, and rated their degree of simulator sickness after each trial. Subjects drove sober and with blood alcohol concentrations (BAC) of approx. 0.5g/L and 0.9g/L in a randomized order. Simulator sickness score (SSS) did not influence the primary outcome measure SDLP. Higher SSS significantly predicted lower average speed and frequency of steering wheel reversals. These effects seemed to be mitigated by alcohol. Higher BAC significantly predicted lower SSS, suggesting that alcohol inebriation alleviates simulator sickness. The negative relation between the number of previous exposures to the simulator and SSS was not statistically significant, but is consistent with habituation to the sickness-inducing effects, as shown in other studies. Overall, the results suggest no influence of simulator sickness on SDLP or several other driving performance measures. However, simulator sickness seems to cause test subjects to drive more carefully, with lower average speed and fewer steering wheel reversals, hampering the interpretation of these outcomes as measures of driving impairment and safety. BAC and repeated simulator exposures may act as confounding variables by influencing the degree of simulator sickness in experimental studies. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Hematological effects of four ethylene glycol monoalkyl ethers in short-term repeated exposure in rats

    Energy Technology Data Exchange (ETDEWEB)

    Starek, Andrzej [Jagiellonian University, Department of Biochemical Toxicology, Medical College, Krakow (Poland); Szymczak, Wieslaw [University of Lodz, Institute of Psychology, Lodz (Poland); Zapor, Lidia [Central Institute for Labour Protection National Research Institute, Laboratory of Toxicology, Department of Chemical and Aerosol Hazards, Warsaw (Poland)

    2008-02-15

    This study was carried out to compare the hematological effects of 2-methoxyethanol (ME), 2-ethoxyethanol (EE), 2-isopropoxyethanol (IPE), and 2-butoxyethanol (BE) in short-term studies in rats. Male rats were subcutaneously treated with ME or EE at a dosage of 0, 1.25, 2.5 and 5.0 mM/kg in saline, 5 days per week, for 4 weeks. Other rats were exposed to IPE or BE at doses of 0, 0.25, 0.5, 0.75 and 1.25 mM/kg in the same manner. Administration of each chemical, except of ME, resulted in a time- and dose-dependent swelling of erythrocytes as evidenced by an increase in mean corpuscular volume (MCV). Subsequently, red blood cells (RBC), packed cell volumes (PCV), hemoglobin concentration (HGB), and mean cell hemoglobin concentration (MCHC) decreased. Furthermore, an increase in mean cell hemoglobin (MCH) and reticulocyte counts was observed. The onset of hemolysis induced by EE, IPE or BE was faster than after ME administration. While in rats exposed to ME hematological changes were strongly pronounced and progressively increased with exposure time beginning from the day 11, those in animals treated with EE were rather persisted at low constant level for all exposure period. In contrast, the rats exposed to IPE and BE demonstrated the dramatic hematological changes more pronounced in case of BE than IPE at the beginning of exposure (on day 4). Despite of exposure duration, these changes were regressed, although the decrease in RBC and MCHC and the increase in MCV and MCH in rats treated with highest doses of both compound (0.5, 0.75, and 1.25 mM/kg) were more persistent, probably due to selective hemolysis of the aged erythrocytes. In addition, significant leukopenia due to reduction of lymphocytes in rats exposed to ME was observed. In summary, this study demonstrated no tolerance to ME- and EE-induced intravascular hemolysis developed under these experimental conditions. On the contrary, tolerance to IPE- and BE-induced hemolysis in rats exposed to these compounds

  7. Arsenic induced apoptosis in rat liver following repeated 60 days exposure

    International Nuclear Information System (INIS)

    Bashir, Somia; Sharma, Yukti; Irshad, M.; Nag, T.C.; Tiwari, Monica; Kabra, M.; Dogra, T.D.

    2006-01-01

    Background: Accumulation of the wide spread environmental toxin arsenic in liver results in hepatotoxcity. Exposure to arsenite and other arsenicals has been previously shown to induce apoptosis in certain tumor cell lines at low (1-3 μM) concentration. Aim: The present study was focused to elucidate the role of free radicals in arsenic toxicity and to investigate the nature of in vivo sodium arsenite induced cell death in liver. Methods: Male wistar rats were exposed to arsenite at three different doses of 0.05, 2.5 and 5 mg/l for 60 days. Oxidative stress in liver was measured by estimating pro-oxidant and antioxidant activity in liver. Histopathological examination of liver was carried out by light and transmission electron microscopy. Analysis of DNA fragmentation by gel electrophoresis was used to identify apoptosis after the exposure. Terminal deoxy-nucleotidyl transferase mediated dUTP Nick end-labeling (TUNEL) assay was used to qualify and quantify apoptosis. Results: A significant increase in cytochrome-P450 and lipid peroxidation accompanied with a significant alteration in the activity of many of the antioxidants was observed, all suggestive of arsenic induced oxidative stress. Histopathological examination under light and transmission electron microscope suggested a combination of ongoing necrosis and apoptosis. DNA-TUNEL showed an increase in apoptotic cells in liver. Agarose gel electrophoresis of DNA of hepatocytes resulted in a characteristic ladder pattern. Conclusion: Chronic arsenic administration induces a specific pattern of apoptosis called post-mitotic apoptosis

  8. Simulation of Feedforward-Feedback Control of Dissolved Oxygen of Microbial Repeated Fed-batch Culture

    Directory of Open Access Journals (Sweden)

    Ling Gao

    2016-09-01

    Full Text Available Fed-batch culture is often used in industry, and dissolved oxygen (DO concentration control is important in fermentation process control. DO control is often applied by using feedback (FB control strategy. But, feedforward-feedback (FF-FB control has the advantage in dealing with the time-varying characteristics resulted from the cell growth during the fermentation process. Mathematical modeling and computer simulation is a useful tool in analysis of the control system.  In this research, the FF-FB DO control and FB substrate control of repeated fed-batch culture process is modeled and simulated. The results showed the feasibility of the control strategy. These results are useful for control system development and process analyses and optimization.

  9. Controlling occupational radiation exposure. Alternatives to regulation

    International Nuclear Information System (INIS)

    Sagan, L.A.; Squitieri, R.; Wildman, S.S.

    1980-01-01

    The principal strategy adopted for the control of occupational radiation exposure has been the establishment of standards expressed as maximum permissible exposures. The use of such standards is subject to a number of defects, among which is the neglect of the economic impact of imposing such standards. Furthermore, such standards carry the implication of a threshold for radiation effects, a concept now widely challenged. Lastly, the use of standards makes it impossible to evaluate the efficiency of the regulatory agency or to compare its performance with other similar agencies. An alternative to the use of standards, i.e. cost-benefit analysis, is discussed. The advantages of this technique meet many of the objections to the use of standards alone and allow health and safety resources to be allocated in a manner most likely to save the most lives. The greatest disadvantage of cost-benefit analysis has been the difficulty in evaluating the benefit side of the equation. Although the risks of radiation exposure are not known with precision, they are nevertheless well understood. Therefore, the application of cost-benefit analysis to occupational radiation exposure is rational. There are a number of barriers to reform in the use of standards and the adoption of cost-benefit analysis. These attitudinal and institutional constraints are discussed. The nature of private or market systems of control are discussed, i.e. the use of liability and insurance mechanisms. These also have shortcomings that require further development but are seen as potentially more efficient for both employer and employee than is the use of regulatory standards. (author)

  10. Stress responses in juvenile pacu (Piaractus mesopotamicus submitted to repeated air exposure - DOI: 10.4025/actascianimsci.v30i1.3618 Stress responses in juvenile pacu (Piaractus mesopotamicus submitted to repeated air exposure - DOI: 10.4025/actascianimsci.v30i1.3618

    Directory of Open Access Journals (Sweden)

    Leonardo Susumu Takahashi

    2008-06-01

    Full Text Available Juvenis de pacu (5,2 Pacu juveniles (5.2 ± 1.5 g were submitted to two one-minute air exposures in a 24 h interval, and sampled before the exposure (control and 5, 15, 30 and 60 min, 24 and 48 h afterwards for whole-body cortisol, sodium, potassium and calcium ion concentrations. For the first air exposure, there was a trend of increased cortisol concentration after 15 min, whereas in the second air exposure, the cortisol concentration increased significantly within 5 min after stress was induced. Sodium ion concentration increased significantly 24 h after both air exposures. Potassium concentration presented fluctuations over the experimental period. Calcium ion concentration increased progressively from 5 to 30 min, in both air exposures. The repeated air exposures exacerbated the cortisol response, but they did not affect the recovery ability of pacu over the experimental period. Additionally, the whole-body cortisol measurement might be a reliable indicator of stress, when sampled fish are smaller and blood volumes are very low, making samples inadequate for analysis1,5 g foram submetidos a duas exposições aéreas de um minuto, em intervalo de 24 horas, e amostrados antes da exposição (controle e 5, 15, 30 e 60 min, 24 e 48 horas depois para análise da concentração corporal de cortisol e dos íons sódio, potássio e cálcio. Na primeira exposição, os peixes apresentaram concentrações de cortisol aumentadas a partir de 15 min, embora não diferissem estatisticamente do controle. Na segunda exposição, a concentração de cortisol aumentou significativamente aos 5 min, retornando às concentrações equivalentes às dos peixes-controle em 30 min. A concentração do íon sódio aumentou significativamente 24 horas depois das duas exposições aéreas. A concentração do íon potássio apresentou flutuações durante o experimento, enquanto a do cálcio apresentou-se reduzida aos 5 min, aumentando gradativamente até os 30 min

  11. Operation control device under radiation exposure

    International Nuclear Information System (INIS)

    Kimura, Kiichi; Murakami, Toichi.

    1994-01-01

    The device of the present invention performs smooth progress of operation by remote control for a plurality of operations in periodical inspections in controlled areas of a nuclear power plant, thereby reducing the operator's exposure dose. Namely, the device monitors the progressing state of the operation by displaying the progress of operation on a CRT of a centralized control device present in a low dose area remote from an operation field through an ITV camera disposed in the vicinity of the operation field. Further, operation sequence and operation instruction procedures previously inputted in the device are indicated to the operation field through an operation instruction outputting device (field CRT) in accordance with the progress of the operation steps. On the other hand, the operation progress can be aided by inputting information from the operation field such as start or completion of the operation steps. Further, the device of the present invention can monitor the change of operation circumstances and exposure dose of operators based on the information from a radiation dose measuring device disposed in the operation circumstance and to individual operators. (I.S.)

  12. Detection of local inflammation induced by repeated exposure to contact allergens by use of IVIS SpectrumCT analyses

    DEFF Research Database (Denmark)

    Nielsen, Morten M.; Schmidt, Jonas D.; Christensen, Jan P.

    2017-01-01

    Background: Contact allergy is characterized by local skin inflammation that, in some cases, can result in systemic immune activation. Objectives: To investigate whether IVIS SpectrumCT analyses can be used to detect the immune response induced by contact allergens. Methods: Mice were repeatedly...... exposed to vehicle or allergens on the ears. The local and systemic responses were analysed at different times with the ProSense 750 FAST probe in IVIS SpectrumCT measurements. In addition, changes in ear thickness, cytokine profile in the skin and immunological phenotype in the draining lymph nodes...... and spleen were determined. Results: Local inflammation was detected by ProSense 750 FAST and correlated with changes in ear thickness, cytokine profile and immunological phenotype following exposure to the strong contact allergen 2,4-dinitrofluorobenzene. Analysis of the systemic response with ProSense 750...

  13. Altered performance in a rat gambling task after acute and repeated alcohol exposure

    NARCIS (Netherlands)

    Spoelder, Marcia; Lesscher, Heidi M B; Hesseling, Peter; Baars, Annemarie M; Lozeman-van T Klooster, José G; Mijnsbergen, Rob; Vanderschuren, Louk J M J

    2015-01-01

    RATIONALE: A bidirectional relationship between alcohol use disorder (AUD) and deficits in impulse control and decision making has been suggested. However, the mechanisms by which neurocognitive impairments predispose to, or result from AUD remain incompletely understood. OBJECTIVES: The aim of this

  14. Neuronal changes and oxidative stress in adolescent rats after repeated exposure to mephedrone

    International Nuclear Information System (INIS)

    López-Arnau, Raúl; Martínez-Clemente, José; Rodrigo, Teresa; Pubill, David; Camarasa, Jorge; Escubedo, Elena

    2015-01-01

    Mephedrone is a new designer drug of abuse. We have investigated the neurochemical/enzymatic changes after mephedrone administration to adolescent rats (3 × 25 mg/kg, s.c. in a day, with a 2 h interval between doses, for two days) at high ambient temperature (26 ± 2 °C), a schedule that intends to model human recreational abuse. In addition, we have studied the effect of mephedrone in spatial learning and memory. The drug caused a transient decrease in weight gain. After the first dose, animals showed hypothermia but, after the subsequent doses, temperature raised over the values of saline-treated group. We observed the development of tolerance to these thermoregulatory effects of mephedrone. Mephedrone induced a reduction of the densities of dopamine (30% in the frontal cortex) and serotonin (40% in the frontal cortex and the hippocampus and 48% in the striatum) transporters without microgliosis. These deficits were also accompanied by a parallel decrease in the expression of tyrosine hydroxylase and tryptophan hydroxylase 2. These changes matched with a down-regulation of D 2 dopamine receptors in the striatum. Mephedrone also induced an oxidative stress evidenced by an increase of lipid peroxidation in the frontal cortex, and accompanied by a rise in glutathione peroxidase levels in all studied brain areas. Drug-treated animals displayed an impairment of the reference memory in the Morris water maze one week beyond the cessation of drug exposure, while the spatial learning process seems to be preserved. These findings raise concerns about the neuronal long-term effects of mephedrone. - Highlights: • We studied the dopaminergic and serotonergic neurotoxicity of mephedrone in rats. • Mephedrone induced a transient hypothermia following sustained hyperthermia. • In a weekend consumption pattern, mephedrone induced selective neurotoxicity. • Mephedrone generated oxidative stress. • Mephedrone induced an impairment in memory function

  15. Neuronal changes and oxidative stress in adolescent rats after repeated exposure to mephedrone

    Energy Technology Data Exchange (ETDEWEB)

    López-Arnau, Raúl; Martínez-Clemente, José [Department of Pharmacology and Therapeutic Chemistry (Pharmacology Section), Faculty of Pharmacy, University of Barcelona (Spain); Institute of Biomedicine (IBUB), Faculty of Pharmacy, University of Barcelona (Spain); Rodrigo, Teresa [Animal Experimentation Unit of Psychology and Pharmacy, University of Barcelona (Spain); Pubill, David [Department of Pharmacology and Therapeutic Chemistry (Pharmacology Section), Faculty of Pharmacy, University of Barcelona (Spain); Institute of Biomedicine (IBUB), Faculty of Pharmacy, University of Barcelona (Spain); Camarasa, Jorge, E-mail: jcamarasa@ub.edu [Department of Pharmacology and Therapeutic Chemistry (Pharmacology Section), Faculty of Pharmacy, University of Barcelona (Spain); Institute of Biomedicine (IBUB), Faculty of Pharmacy, University of Barcelona (Spain); Escubedo, Elena [Department of Pharmacology and Therapeutic Chemistry (Pharmacology Section), Faculty of Pharmacy, University of Barcelona (Spain); Institute of Biomedicine (IBUB), Faculty of Pharmacy, University of Barcelona (Spain)

    2015-07-01

    Mephedrone is a new designer drug of abuse. We have investigated the neurochemical/enzymatic changes after mephedrone administration to adolescent rats (3 × 25 mg/kg, s.c. in a day, with a 2 h interval between doses, for two days) at high ambient temperature (26 ± 2 °C), a schedule that intends to model human recreational abuse. In addition, we have studied the effect of mephedrone in spatial learning and memory. The drug caused a transient decrease in weight gain. After the first dose, animals showed hypothermia but, after the subsequent doses, temperature raised over the values of saline-treated group. We observed the development of tolerance to these thermoregulatory effects of mephedrone. Mephedrone induced a reduction of the densities of dopamine (30% in the frontal cortex) and serotonin (40% in the frontal cortex and the hippocampus and 48% in the striatum) transporters without microgliosis. These deficits were also accompanied by a parallel decrease in the expression of tyrosine hydroxylase and tryptophan hydroxylase 2. These changes matched with a down-regulation of D{sub 2} dopamine receptors in the striatum. Mephedrone also induced an oxidative stress evidenced by an increase of lipid peroxidation in the frontal cortex, and accompanied by a rise in glutathione peroxidase levels in all studied brain areas. Drug-treated animals displayed an impairment of the reference memory in the Morris water maze one week beyond the cessation of drug exposure, while the spatial learning process seems to be preserved. These findings raise concerns about the neuronal long-term effects of mephedrone. - Highlights: • We studied the dopaminergic and serotonergic neurotoxicity of mephedrone in rats. • Mephedrone induced a transient hypothermia following sustained hyperthermia. • In a weekend consumption pattern, mephedrone induced selective neurotoxicity. • Mephedrone generated oxidative stress. • Mephedrone induced an impairment in memory function.

  16. Repeated exposure to Lutzomyia intermedia sand fly saliva induces local expression of interferon-inducible genes both at the site of injection in mice and in human blood.

    Science.gov (United States)

    Weinkopff, Tiffany; de Oliveira, Camila I; de Carvalho, Augusto M; Hauyon-La Torre, Yazmin; Muniz, Aline C; Miranda, Jose Carlos; Barral, Aldina; Tacchini-Cottier, Fabienne

    2014-01-01

    During a blood meal, Lutzomyia intermedia sand flies transmit Leishmania braziliensis, a parasite causing tegumentary leishmaniasis. In experimental leishmaniasis, pre-exposure to saliva of most blood-feeding sand flies results in parasite establishment in absence of any skin damages in mice challenged with dermotropic Leishmania species together with saliva. In contrast, pre-immunization with Lu. intermedia salivary gland sonicate (SGS) results in enhanced skin inflammatory exacerbation upon co-inoculation of Lu. intermedia SGS and L. braziliensis. These data highlight potential unique features of both L. braziliensis and Lu. intermedia. In this study, we investigated the genes modulated by Lu. intermedia SGS immunization to understand their potential impact on the subsequent cutaneous immune response following inoculation of both SGS and L. braziliensis. The cellular recruitment and global gene expression profile was analyzed in mice repeatedly inoculated or not with Lu. intermedia. Microarray gene analysis revealed the upregulation of a distinct set of IFN-inducible genes, an immune signature not seen to the same extent in control animals. Of note this INF-inducible gene set was not induced in SGS pre-immunized mice subsequently co-inoculated with SGS and L. braziliensis. These data suggest the parasite prevented the upregulation of this Lu. intermedia saliva-related immune signature. The presence of these IFN-inducible genes was further analyzed in peripheral blood mononuclear cells (PBMCs) sampled from uninfected human individuals living in a L. braziliensis-endemic region of Brazil thus regularly exposed to Lu. intermedia bites. PBMCs were cultured in presence or absence of Lu. intermedia SGS. Using qRT-PCR we established that the IFN-inducible genes induced in the skin of SGS pre-immunized mice, were also upregulated by SGS in PBMCs from human individuals regularly exposed to Lu. intermedia bites, but not in PBMCs of control subjects. These data demonstrate

  17. Repeated stressor exposure enhances contextual fear memory in a beta-adrenergic receptor-dependent process and increases impulsivity in a non-beta receptor-dependent fashion.

    Science.gov (United States)

    Camp, Robert M; Johnson, John D

    2015-10-15

    Memory formation is promoted by stress via the release of norepinephrine and stimulation of beta-adrenergic receptors (β-ARs). Previous data demonstrate that repeated stressor exposure increases norepinephrine turnover and β-AR signaling within the amygdala, which led to the hypothesis that some stress-induced behavioral changes are likely due to facilitated associative learning. To test this, Fischer rats were exposed to chronic mild stress for four days. On day 5, subjects (including non-stressed controls) were injected with the beta-blocker propranolol or vehicle prior to conditioning in an operant box (animals receive two mild foot shocks) or passive avoidance apparatus (animals received a foot shock upon entry into the dark chamber). Twenty-four hours later, subjects were returned to the operant box for measurement of freezing or returned to the passive avoidance apparatus for measurement of latency to enter the dark chamber. Subjects were also tested in an open field to assess context-independent anxiety-like behavior. Animals exposed to chronic stress showed significantly more freezing behavior in the operant box than did controls, and this exaggerated freezing was blocked by propranolol during the conditioning trial. There was no effect of stress on behavior in the open field. Unexpectedly, retention latency was significantly reduced in subjects exposed to chronic stress. These results indicate that chronic exposure to stress results in complex behavioral changes. While repeated stress appears to enhance the formation of fearful memories, it also results in behavioral responses that resemble impulsive behaviors that result in poor decision-making. Copyright © 2015 Elsevier Inc. All rights reserved.

  18. Monitoring and control of occupational radiation exposure in Switzerland

    International Nuclear Information System (INIS)

    Moser, M.

    1997-01-01

    Occupational exposure is the most prominent example for the prolonged exposure to low level ionizing radiation characterized by low doses and dose rates. In this paper the occupational exposure in Switzerland is presented and the regulatory control of this exposure in the framework of the new radiation protection regulations is discussed. (author)

  19. Repeated Strains, Social Control, Social Learning, and Delinquency: Testing an Integrated Model of General Strain Theory in China

    Science.gov (United States)

    Bao, Wan-Ning; Haas, Ain; Chen, Xiaojin; Pi, Yijun

    2014-01-01

    In Agnew's general strain theory, repeated strains can generate crime and delinquency by reducing social control and fostering social learning of crime. Using a sample of 615 middle-and high-school students in China, this study examines how social control and social learning variables mediate the effect of repeated strains in school and at home on…

  20. Adaptation of the pituitary-adrenal axis to daily repeated forced swim exposure in rats is dependent on the temperature of water.

    Science.gov (United States)

    Rabasa, Cristina; Delgado-Morales, Raúl; Gómez-Román, Almudena; Nadal, Roser; Armario, Antonio

    2013-11-01

    Comparison of exposure to certain predominantly emotional stressors reveals a qualitatively similar neuroendocrine response profile as well as a reduction of physiological responses after daily repeated exposure (adaptation). However, particular physical components of the stressor may interfere with adaptation. As defective adaptation to stress can enhance the probability to develop pathologies, we studied in adult male rats (n = 10/group) swimming behavior (struggling, immobility and mild swim) and physiological responses (ACTH, corticosterone and rectal temperature) to daily repeated exposure to forced swim (20 min, 13 d) at 25 or 36 °C (swim25 or swim36). Rats were repeatedly blood-sampled by tail-nick and hormones measured by radioimmunoassay. Some differences were observed between the two swim temperature groups after the first exposure to forced swim: (a) active behaviors were greater in swim25 than swim36 groups; (b) swim25 but not swim36 caused hypothermia; and (c) swim36 elicited the same ACTH response as swim25, but plasma corticosterone concentration was lower for swim36 at 30 min post-swim. After daily repeated exposure, adaptation in ACTH secretion was observed with swim36 already on day 4, whereas with swim25 adaptation was not observed until day 13 and was of lower magnitude. Nevertheless, after repeated exposure to swim25 a partial protection from hypothermia was observed and the two swim conditions resulted in progressive reduction of active behaviors. Thus, daily repeated swim at 25 °C impairs adaptation of the hypothalamic-pituitary-adrenal axis as compared to swim at 36 °C, supporting the hypothesis that certain physical components of predominantly emotional stressors can interfere with the process of adaptation.

  1. In utero exposure to nanosized carbon black (Printex90) does not induce tandem repeat mutations in female murine germ cells

    DEFF Research Database (Denmark)

    Boisen, Anne Mette Zenner; Shipley, Thomas; Jackson, Petra

    2013-01-01

    Inhalation of particles has been shown to induce mutations in the male germline in mice following both prenatal and adult exposures in several experiments. In contrast, the effects of particles on female germ cell mutagenesis are not well established. Germline mutations are induced during active...... cell division, which occurs during fetal development in females. We investigated the effects of prenatal exposure to carbon black nanoparticles (CB) on induction of mutations in the female mouse germline during fetal development, spanning the critical developmental stages of oogenesis. Pregnant C57BL/6...... mutation rates in the resulting F2 generation were determined from full pedigrees (mother, father, offspring) of F1 female mice (178 CB-exposed and 258 control F2 offspring). ESTR mutation rates in CB-exposed F2 female offspring were not statistically different from those of F2 female control offspring....

  2. Comparative electrophysiological evaluation of hippocampal function following repeated inhalation exposures to JP-8, Jet A, JP-5, and the synthetic Fischer Tropsch fuel.

    Science.gov (United States)

    Rohan, Joyce G; McInturf, Shawn M; Miklasevich, Molly K; Gut, Chester P; Grimm, Michael D; Reboulet, James E; Howard, William R; Mumy, Karen L

    2018-01-01

    Exposure to fuels continues to be a concern in both military and general populations. The aim of this study was to examine effects of in vivo rat repeated exposures to different types of jet fuel utilizing microelectrode arrays for comparative electrophysiological (EP) measurements in hippocampal slices. Animals were exposed to increasing concentrations of four jet fuels, Jet Propellant (JP)-8, Jet A, JP-5, or synthetic Fischer Tropsch (FT) fuel via whole-body inhalation for 20 d (6 hr/d, 5 d/week for 28 d) and synaptic transmission as well as behavioral performance were assessed. Our behavioral studies indicated no significant changes in behavioral performance in animals exposed to JP-8, Jet A, or JP-5. A significant deviation in learning pattern during the Morris water maze task was observed in rats exposed to the highest concentration of FT (2000 mg/m 3 ). There were also significant differences in the EP profile of hippocampal neurons from animals exposed to JP-8, Jet A, JP-5, or FT compared to control air. However, these differences were not consistent across fuels or dose dependent. As expected, patterns of EP alterations in brain slices from JP-8 and Jet A exposures were more similar compared to those from JP-5 and FT. Further longitudinal investigations are needed to determine if these EP effects are transient or persistent. Such studies may dictate if and how one may use EP measurements to indicate potential susceptibility to neurological impairments, particularly those that result from inhalation exposure to chemicals or mixtures.

  3. Effect of replacing sugar with non-caloric sweeteners in beverages on the reward value after repeated exposure.

    Directory of Open Access Journals (Sweden)

    Sanne Griffioen-Roose

    Full Text Available BACKGROUND: The reward value of food is partly dependent on learned associations. It is not yet known whether replacing sugar with non-caloric sweeteners in food is affecting long-term acceptance. OBJECTIVE: To determine the effect of replacing sugar with non-caloric sweeteners in a nutrient-empty drink (soft drink versus nutrient-rich drink (yoghurt drink on reward value after repeated exposure. DESIGN: We used a randomized crossover design whereby forty subjects (15 men, 25 women with a mean ± SD age of 21 ± 2 y and BMI of 21.5 ± 1.7 kg/m(2 consumed a fixed portion of a non-caloric sweetened (NS and sugar sweetened (SS versions of either a soft drink or a yoghurt drink (counterbalanced for breakfast which were distinguishable by means of colored labels. Each version of a drink was offered 10 times in semi-random order. Before and after conditioning the reward value of the drinks was assessed using behavioral tasks on wanting, liking, and expected satiety. In a subgroup (n=18 fMRI was performed to assess brain reward responses to the drinks. RESULTS: Outcomes of both the behavioral tasks and fMRI showed that conditioning did not affect the reward value of the NS and SS versions of the drinks significantly. Overall, subjects preferred the yoghurt drinks to the soft drinks and the ss drinks to the NS drinks. In addition, they expected the yoghurt drinks to be more satiating, they reduced hunger more, and delayed the first eating episode more. Conditioning did not influence these effects. CONCLUSION: Our study showed that repeated consumption of a non-caloric sweetened beverage, instead of a sugar sweetened version, appears not to result in changes in the reward value. It cannot be ruled out that learned associations between sensory attributes and food satiating capacity which developed preceding the conditioning period, during lifetime, affected the reward value of the drinks.

  4. Effect of replacing sugar with non-caloric sweeteners in beverages on the reward value after repeated exposure.

    Science.gov (United States)

    Griffioen-Roose, Sanne; Smeets, Paul A M; Weijzen, Pascalle L G; van Rijn, Inge; van den Bosch, Iris; de Graaf, Cees

    2013-01-01

    The reward value of food is partly dependent on learned associations. It is not yet known whether replacing sugar with non-caloric sweeteners in food is affecting long-term acceptance. To determine the effect of replacing sugar with non-caloric sweeteners in a nutrient-empty drink (soft drink) versus nutrient-rich drink (yoghurt drink) on reward value after repeated exposure. We used a randomized crossover design whereby forty subjects (15 men, 25 women) with a mean ± SD age of 21 ± 2 y and BMI of 21.5 ± 1.7 kg/m(2) consumed a fixed portion of a non-caloric sweetened (NS) and sugar sweetened (SS) versions of either a soft drink or a yoghurt drink (counterbalanced) for breakfast which were distinguishable by means of colored labels. Each version of a drink was offered 10 times in semi-random order. Before and after conditioning the reward value of the drinks was assessed using behavioral tasks on wanting, liking, and expected satiety. In a subgroup (n=18) fMRI was performed to assess brain reward responses to the drinks. Outcomes of both the behavioral tasks and fMRI showed that conditioning did not affect the reward value of the NS and SS versions of the drinks significantly. Overall, subjects preferred the yoghurt drinks to the soft drinks and the ss drinks to the NS drinks. In addition, they expected the yoghurt drinks to be more satiating, they reduced hunger more, and delayed the first eating episode more. Conditioning did not influence these effects. Our study showed that repeated consumption of a non-caloric sweetened beverage, instead of a sugar sweetened version, appears not to result in changes in the reward value. It cannot be ruled out that learned associations between sensory attributes and food satiating capacity which developed preceding the conditioning period, during lifetime, affected the reward value of the drinks.

  5. INFLUENCE OF MORINGA OLEIFERA (DRUM-STICK FRUIT EXTRACT ON HAEMATOLOGICAL PROFILE FOLLOWING REPEATED EXPOSURE TO LOW LEVELS OF ARSENIC THROUGH FEED ON RATS

    Directory of Open Access Journals (Sweden)

    Vaibhav R. Pachade

    2012-01-01

    Full Text Available Effect of Moringa oleifera fruits hot methanolic extract (MFE, if any, in minimizing the adverse reactions of repeated exposure to arsenic trioxide (AT in feed was investigated in Wistar rats with reference to haematological profile. Three groups of rats each containing 10 (5male+5female were used. The group I served as negative control. Rats of group II were fed arsenic trioxide (AT alone @ 100 ppm in feed while those of group III simultaneously received AT (@100 ppm and MFE (50 mg/kg/day for 28 days. Blood samples were collected from retroorbital plexus for estimation of hematological parameters (haemoglobin, PCV, TEC, MCH, MCHC, MCV of different groups on 0 day, 15th day and 29th day respectively. Exposure to AT through feed in group II resulted in significant (P<0.05 decrease in haemoglobin, TEC and MCHC, accompanied by increased MCV, with no significant alteration of PCV or MCH of the rats. While rats of group III treated with AT (@100 ppm and MFE (50 mg/kg/day also resulted in same consequences as it was in group II but it was slightly less than that of group II suggesting of mild non significant protective effect.

  6. Assessment and control of fetal exposure

    International Nuclear Information System (INIS)

    Harty, R.; Swinth, K.L.; Traub, R.J.

    1991-10-01

    The assessment and control of fetal exposure to radiation in the workplace is an issue that is complicated by both biological and political/social ramifications. As a result of the dramatic increase in the number of women employed as radiation workers during the past 10 years, many facilities using radioactive materials have instituted fetal protection programs with special requirements for female radiation workers. It is necessary, however, to ensure that any fetal protection program be developed in such a way as to be nondiscriminatory. A study has been initiated whose purpose is to balance the political/social and the biological ramifications associated with occupational protection of the developing embryo/fetus. Several considerations are involved in properly balancing these factors. These considerations include appropriate methods of declaring the pregnancy, training workers, controlling the dose to the embryo/fetus, measuring and calculating the dose to the embryo/fetus, and recording the pertinent information. Alternative strategies for handling these factors while ensuring maximum protection of the embryo/fetus and the rights and responsibilities of employees and employers are discussed

  7. Is repeated exposure the holy grail for increasing children's vegetable intake? Lessons learned from a Dutch childcare intervention using various vegetable preparations

    NARCIS (Netherlands)

    Zeinstra, Gertrude G.; Vrijhof, Milou; Kremer, Stefanie

    2018-01-01

    Children's failure to eat enough vegetables highlights the need for effective interventions encouraging this behaviour. The aim of this study was to investigate the effect of repeated exposure to three a priori unfamiliar vegetables, each prepared in two ways, on children's vegetable acceptance in a

  8. Anti-Inflammatory and Antioxidant Effects of Repeated Exposure to Cruciferous Allyl Nitrile in Sensitizer-Induced Ear Edema in Mice.

    Science.gov (United States)

    Tanii, Hideji; Sugitani, Kayo; Saijoh, Kiyofumi

    2016-02-29

    Skin sensitizers induce allergic reactions through the induction of reactive oxygen species. Allyl nitrile from cruciferous vegetables has been reported to induce antioxidants and phase II detoxification enzymes in various tissues. We assessed the effects of repeated exposure to allyl nitrile on sensitizer-induced allergic reactions. Mice were dosed with allyl nitrile (0-200 µmol/kg), and then received a dermal application of 1 of 3 sensitizers on the left ear or 1 of 2 vehicles on the right ear. Quantitative assessment of edema was carried out by measuring the difference in weight between the portions taken from the right and left ears. We tested enzymes (superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and thiobarbituric acid reactive substances (TBARS) in ears. Repeated exposure to allyl nitrile reduced edemas induced by glutaraldehyde and by 2, 4-dinitrochlorobenzene (DNCB), but not by formaldehyde. The repeated exposure decreased levels of TBARS, a marker of oxidative stress, induced by glutaraldehyde and by DNCB, but not by formaldehyde. Allyl nitrile elevated SOD levels for the 3 sensitizers, and CAT levels for formaldehyde and DNCB. Allyl nitrile also increased GPx levels for formaldehyde and DNCB, but not for glutaraldehyde. The reduced edemas were associated with changes in oxidative stress levels and antioxidant enzymes. Repeated exposure to allyl nitrile reduced allergic reactions induced by glutaraldehyde and by DNCB, but not by formaldehyde. This reduction was associated with changes in ROS levels and antioxidant enzyme activities.

  9. Identification of genomic biomarkers for anthracycline-induced cardiotoxicity in human iPSC-derived cardiomyocytes: an in vitro repeated exposure toxicity approach for safety assessment

    NARCIS (Netherlands)

    Chaudhari, U.; Nemade, H.; Wagh, V.; Ellis, J.K.; Srinivasan, S.; Louisse, J.

    2016-01-01

    The currently available techniques for the safety evaluation of candidate drugs are usually cost-intensive and time-consuming and are often insufficient to predict human relevant cardiotoxicity. The purpose of this study was to develop an in vitro repeated exposure toxicity methodology allowing the

  10. Acquired Apraxia of Speech: The Effects of Repeated Practice and Rate/Rhythm Control Treatments on Sound Production Accuracy

    Science.gov (United States)

    Wambaugh, Julie L.; Nessler, Christina; Cameron, Rosalea; Mauszycki, Shannon C.

    2012-01-01

    Purpose: This investigation was designed to elucidate the effects of repeated practice treatment on sound production accuracy in individuals with apraxia of speech (AOS) and aphasia. A secondary purpose was to determine if the addition of rate/rhythm control to treatment provided further benefits beyond those achieved with repeated practice.…

  11. Personalized Video Feedback and Repeated Task Practice Improve Laparoscopic Knot-Tying Skills: Two Controlled Trials.

    Science.gov (United States)

    Abbott, Eduardo F; Thompson, Whitney; Pandian, T K; Zendejas, Benjamin; Farley, David R; Cook, David A

    2017-11-01

    Compare the effect of personalized feedback (PF) vs. task demonstration (TD), both delivered via video, on laparoscopic knot-tying skills and perceived workload; and evaluate the effect of repeated practice. General surgery interns and research fellows completed four repetitions of a simulated laparoscopic knot-tying task at one-month intervals. Midway between repetitions, participants received via e-mail either a TD video (demonstration by an expert) or a PF video (video of their own performance with voiceover from a blinded senior surgeon). Each participant received at least one video per format, with sequence randomly assigned. Outcomes included performance scores and NASA Task Load Index (NASA-TLX) scores. To evaluate the effectiveness of repeated practice, scores from these trainees on a separate delayed retention test were compared against historical controls who did not have scheduled repetitions. Twenty-one trainees completed the randomized study. Mean change in performance scores was significantly greater for those receiving PF (difference = 23.1 of 150 [95% confidence interval (CI): 0, 46.2], P = .05). Perceived workload was also significantly reduced (difference = -3.0 of 20 [95% CI: -5.8, -0.3], P = .04). Compared with historical controls (N = 93), the 21 with scheduled repeated practice had higher scores on the laparoscopic knot-tying assessment two weeks after the final repetition (difference = 1.5 of 10 [95% CI: 0.2, 2.8], P = .02). Personalized video feedback improves trainees' procedural performance and perceived workload compared with a task demonstration video. Brief monthly practice sessions support skill acquisition and retention.

  12. Effects of Diet and Genetics on Growth Performance of Pigs in Response to Repeated Exposure to Heat Stress

    Directory of Open Access Journals (Sweden)

    Wendy M. Rauw

    2017-10-01

    Full Text Available Heat stress (HS is one of the costliest issues in the U.S. pork industry. Aims of the present study were to determine the consequences of repeated exposure to HS on growth performance, and the effects of a high fiber diet, the genetic potential for high lean tissue accretion, and the genetic potential for residual feed intake (RFI on resilience to HS. Barrows (n = 97 from three genetic lines (commercial, high RFI, low RFI where subjected three times to a 4-day HS treatment (HS1, HS2, and HS3 which was preceded by a 9-day neutral (TN adaptation period (TN1 and alternated by 7-day periods of neutral temperatures (TN2, TN3, and TN4. Body weight gain (BWG, feed intake (FI, feed conversion efficiency (FCE, RFI, and the drop in BWG and FI between TN and HS were estimated for each period, and slaughter traits were measured at the end of TN4. Commercial pigs had lower FI when fed a high fiber diet compared to a regular diet (2.70 ± 0.08 vs. 2.96 ± 0.08 kg/d; P < 0.05, while no differences were found for BWG, RFI or FCE. HS reduced FI, BWG, and FCE, increased RFI, and resulted in leaner pigs that generate smaller carcasses at slaughter. In TN, commercial pigs grew faster than the low and high RFI pigs (1.22 ± 0.06 vs. 0.720 ± 0.05 and 0.657 ± 0.07; P < 0.001 but growth rates were not significantly different between the lines during HS. Growth rates for the low RFI and high RFI pigs were similar both during TN and during HS. Pigs of interest for genetic improvement are those that are able to maintain growth rates during HS. Our results show that response in growth to HS was repeatable over subsequent 4-d HS cycles, which suggests the potential for including this response in the breeding index. The best performing animals during HS are likely those that are not highly superior for growth in TN.

  13. Biochemical and histopathological changes in the kidney and adrenal gland of rats following repeated exposure to lambda-cyhalothrin

    OpenAIRE

    Hassina Khaldoun Oularbi

    2014-01-01

    Lambda-cyhalothrin (LCT) is a type II pyrethroid insecticide widely used in pest management. This study was undertaken to evaluate the toxic effects of LCT on the kidneys and adrenal glands of rats after subacute exposure. Twenty-eight 6-week-old male albino Rattus norvegicus rats were randomly assigned to four groups. Group 1 was the control group, which received distilled water. The experimental groups 2, 3 and 4 received 20.4, 30.6 and 61.2 mg/kg body weight, respectively, of LCT, administ...

  14. Practical methods for exposure control/management at nuclear facilities

    International Nuclear Information System (INIS)

    Twiggs, J.A.

    1991-01-01

    Exposure management/reduction is very important to Duke Power Company. Practical exposure control/reduction techniques applied to their reactor vessel head disassembly outage activity have consistently reduced personnel exposure for this task. The following exposure control methods have worked for use and will be the industry's direction for the 1990's. A summary of these methods includes: (a) move the responsibility of exposure management from the Radiation Protection group to the Maintenance group; (b) reduce area source term by removal of source; (c) improve working environments in radiation areas by minimizing protective clothing usage; and (d) maximize the use of electronic instruments to allow remote monitoring

  15. Effects of short-term repeated exposure to different flooring surfaces on the behavior and physiology of dairy cattle.

    Science.gov (United States)

    Schütz, K E; Cox, N R

    2014-05-01

    during the stand-off period. We observed no major effect of the repeated stand-off exposure. In summary, adding rubber matting onto concrete surfaces for stand-off purposes is beneficial for animal welfare. A well-managed wood chip surface offered the best welfare for dairy cows removed from pasture, and the findings of this study confirm that a concrete surface decreases the welfare of cows removed from pasture. Copyright © 2014 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  16. Incentive systems for food quality control with repeated deliveries: Salmonella control in pork production

    NARCIS (Netherlands)

    King, R.P.; Backus, G.B.C.; Gaag, van der M.A.

    2007-01-01

    This paper presents a dynamic principal-agent analysis of incentive systems for Salmonella control. The European Union will require Salmonella testing from 2008. On the basis of the producer's performance history in controlling Salmonella, the incentive systems analysed determine quality premiums to

  17. Repeated exposure to media messages encouraging parent-child communication about sex: differential trajectories for mothers and fathers.

    Science.gov (United States)

    Blitstein, Jonathan L; Evans, W Douglas; Davis, Kevin C; Kamyab, Kian

    2012-01-01

    To examine changes in parent-child communication related to sexual behavior after exposure to public health messages. Randomized, controlled trial that was part of precampaign message testing. Exposure occurred online or through DVDs mailed to participants and viewed on their personal computers. Data collection occurred via a secure Web site. Participants included parents (n  =  1969) living with a child age 10 to 14 years drawn from a nationally representative sample of U.S. households. Treatment participants were exposed to video, audio, and print advertisements that promoted the benefits of speaking to their children early and often about delaying initiation of sexual activity; messages also directed parents to an informational Web site. The dependent variable assessed frequency of parent-child communication related to sexual behavior. The primary independent variable was treatment assignment. Longitudinal growth modeling that included five waves of data. The trajectory of growth over time differed between fathers in the treatment group and fathers in the control group (F[1, 2357]  =  4.15; p groups. This study demonstrates that father-child and mother-child communication patterns differ over time in response to public health messages. Findings have implication for researchers developing health marketing campaigns.

  18. Exposure Control--OSHA's Bloodborne Pathogens Standard.

    Science.gov (United States)

    Granville, Mark F.

    1993-01-01

    Explains schools' responsibilities in complying with the Occupational Safety and Health Administration's (OSHA) Bloodborne Pathogens Standard. Describes exposure determination plan, protective equipment, housekeeping practices, labeling of waste, training employees, hepatitis B vaccinations, postexposure evaluation and medical follow-up, and…

  19. Control of radiation exposure (principles and methods)

    International Nuclear Information System (INIS)

    Agwimah, R. I.

    1999-01-01

    Biological risks are directly related to the tissue radiation dose, so it is very important to maintain personnel doses as low as realistically possible. This goal can be achieved by minimizing internal contamination and external exposure to radioactive sources

  20. A repeated short educational intervention improves asthma control and quality of life.

    Science.gov (United States)

    Plaza, Vicente; Peiró, Meritxell; Torrejón, Montserrat; Fletcher, Monica; López-Viña, Antolín; Ignacio, José María; Quintano, José Antonio; Bardagí, Santiago; Gich, Ignasi

    2015-11-01

    We assessed the effectiveness of an asthma educational programme based on a repeated short intervention (AEP-RSI) to improve asthma control (symptom control and future risk) and quality of life. A total of 230 adults with mild-to-moderate persistent uncontrolled asthma participated in a 1-year cluster randomised controlled multicentre study. The AEP-RSI was given in four face-to-face sessions at 3-month intervals, and included administration of a written personalised action plan and training on inhaler technique. Centres were randomised to the AEP-RSI (intervention) group or usual clinical practice group. Specialised centres using a standard educational programme were the gold standard group. A significant improvement in the Asthma Control Test score was observed in all three groups (pQuality of Life Questionnaire scores (0.95±1.04 and 0.89±0.84 versus 0.52±0.97, respectively). The AEP-RSI was effective in improving asthma symptom control, future risk and quality of life. Copyright ©ERS 2015.

  1. Blood pressure control in hypertensive pediatric renal transplants: role of repeated ABPM following transplantation.

    Science.gov (United States)

    Krmar, Rafael T; Berg, Ulla B

    2008-10-01

    Hypertension in pediatric renal transplants is a widespread condition associated with high mortality risk in early adult life. Ambulatory blood pressure monitoring (ABPM) was found to be superior to office blood pressure (BP) in identifying true hypertensive and responders to treatment. The aim of this study was to investigate the role of repeated ABPM, performed at yearly intervals following transplantation, in the assessment and decision-making processes of post-transplant hypertension. Thirty-seven recipients (23 males; aged 10.5 +/- 4.3 years) who were followed for 4.3 +/- 2.2 years (range 2-9) after transplantation were eligible for analysis. The mean follow-up time between the baseline (1 year post-transplantation) and the most recent ABPM examination was 3.3 +/- 2.2 years (range 1-8). Throughout the follow-up period, antihypertensive therapy was either started or intensified in 27 recipients. These interventions were decided based on ABPM results obtained on 40 of 44 occasions. At last follow-up, 24 of 29 treated hypertensive recipients displayed controlled BP. This figure was significantly higher compared to our historical hypertensive control recipients in whom ABPM was applied for the first time in treatment at 6 +/- 3.3 years (range 2-15) after transplantation, while therapeutic decisions were driven by office BP measurements (95 % confidence interval (95% CI) for the difference between proportions (80.6-32 %) 36-60 %, P = 0.001). Our study shows that, in a population with high risk for hypertension, repeated ABPM may significantly help to improve BP control.

  2. Chronic repeated exposure to weather-related stimuli elicits few symptoms of chronic stress in captive molting and non-molting European starlings (Sturnus vulgaris).

    Science.gov (United States)

    de Bruijn, Robert; Reed, J Michael; Romero, L Michael

    2017-10-01

    Repeated exposure to acute stressors causes dramatic changes in an animal's stress physiology and the cumulative effects are often called chronic stress. Recently we showed that short-term exposure to weather-related stimuli, such as temperature change, artificial precipitation, and food restriction, cause acute responses in captive European starlings (Sturnus vulgaris). Here, we examined the effect of repeated exposure to weather-related stressors on heart rate and corticosterone (CORT) of captive non-molting and molting European starlings. Four times every day for 3 weeks, birds were exposed to either 30 min of a subtle (3°C) decrease in temperature, a short bout of simulated rain, or 2 hr of food removal. The order and time of presentation were randomly assigned on each day. We found no differences in heart rate or heart rate variability. Furthermore, there were no changes in baseline CORT levels, CORT negative feedback efficacy, or maximal adrenal capacity. Mass increased across the experimental period only in molting birds. CORT responses to restraint were decreased in both groups following treatment, suggesting the birds had downregulated their responses to acute stress. Molting birds showed evidence of suppression of the HPA axis compared with non-molting birds, which is consistent with previous research. Overall, our data show that repeated exposure to weather-related stressors does not elicit most of the symptoms normally associated with chronic stress. © 2018 Wiley Periodicals, Inc.

  3. Development and evaluation of an Exposure Control Efficacy Library (ECEL)

    NARCIS (Netherlands)

    Fransman, W.; Schinkel, J.; Meijster, T.; Hemmen, J. van; Tielemans, E.; Goede, H.

    2008-01-01

    Objectives: This paper describes the development and evaluation of an evidence database on the effectiveness of risk management measures (RMMs) to control inhalation exposure. This database is referred to as Exposure Control Efficacy Library (ECEL). Methods: A comprehensive review of scientific

  4. Repeated exposure to two stressors in sequence demonstrates that corticosterone and paraventricular nucleus of the hypothalamus interleukin-1β responses habituate independently.

    Science.gov (United States)

    Lovelock, D F; Deak, T

    2017-09-01

    A wide range of stress-related pathologies such as post-traumatic stress disorder are considered to arise from aberrant or maladaptive forms of stress adaptation. The hypothalamic-pituitary-adrenal (HPA) axis readily adapts to repeated stressor exposure, yet little is known about adaptation in neuroimmune responses to repeated or sequential stress challenges. In Experiment 1, rats were exposed to 10 days of restraint alone (60 minutes daily), forced swim alone (30 minutes daily) or daily sequential exposure to restraint (60 minutes) followed immediately by forced swim (30 minutes), termed sequential stress exposure. Habituation of the corticosterone (CORT) response occurred to restraint by 5 days and swim at 10 days, whereas rats exposed to sequential stress exposure failed to display habituation to the combined challenge. Experiment 2 compared 1 or 5 days of forced swim with sequential stress exposure and examined how each affected expression of several neuroimmune and cellular activation genes in the paraventricular nucleus of the hypothalamus (PVN), prefrontal cortex (PFC) and hippocampus (HPC). Sequential exposure to restraint and swim increased interleukin (IL)-1β in the PVN, an effect that was attenuated after 5 days. Sequential stress exposure also elicited IL-6 and tumour necrosis factor-α responses in the HPC and PFC, respectively, which did not habituate after 5 days. Experiment 3 tested whether prior habituation to restraint (5 days) would alter the IL-1β response evoked by swim exposure imposed immediately after the sixth day of restraint. Surprisingly, a history of repeated exposure to restraint attenuated the PVN IL-1β response after swim in comparison to acutely-exposed subjects despite an equivalent CORT response. Overall, these findings suggest that habituation of neuroimmune responses to stress proceeds: (i) independent of HPA axis habituation; (ii) likely requires more daily sessions of stress to develop; and (iii) IL-1β displays

  5. Control of radiation exposures by decontamination

    International Nuclear Information System (INIS)

    LeSurf, J.E.

    1981-01-01

    The radiation exposures of workers at light water and heavy water cooled reactors can be reduced by dilute chemical decontamination as exemplified by the CAN-DECON process. The cost effectiveness of the CAN-DECON process is illustrated by actual service experience and by hypothetical cases

  6. Repeated Exposure to the “Spice” Cannabinoid JWH-018 Induces Tolerance and Enhances Responsiveness to 5-HT1A Receptor Stimulation in Male Rats

    Directory of Open Access Journals (Sweden)

    Joshua S. Elmore

    2018-02-01

    Full Text Available Naphthalen-1-yl-(1-pentylindol-3-ylmethanone (JWH-018 is a synthetic compound found in psychoactive “spice” products that activates cannabinoid receptors. Preclinical evidence suggests that exposure to synthetic cannabinoids increases 5-HT2A/2C receptor function in the brain, an effect which might contribute to psychotic symptoms. Here, we hypothesized that repeated exposures to JWH-018 would enhance behavioral responsiveness to the 5-HT2A/2C receptor agonist DOI. Male Sprague-Dawley rats fitted with subcutaneously (sc temperature transponders received daily injections of JWH-018 (1.0 mg/kg, sc or its vehicle for seven consecutive days. Body temperature and catalepsy scores were determined at 1, 2, and 4 h post-injection each day. At 1 and 7 days after the final repeated treatment, rats received a challenge injection of either DOI (0.1 mg/kg, sc or the 5-HT1A receptor agonist 8-OH-DPAT (0.3 mg/kg, sc, then temperature and behavioral responses were assessed. Behaviors induced by DOI included wet dog shakes and back muscle contractions (i.e., skin jerks, while behaviors induced by 8-OH-DPAT included ambulation, forepaw treading, and flat body posture. On the first day of repeated treatment, JWH-018 produced robust hypothermia and catalepsy which lasted up to 4 h, and these effects were significantly blunted by day 7 of treatment. Repeated exposure to JWH-018 did not affect behaviors induced by DOI, but behavioral and hypothermic responses induced by 8-OH-DPAT were significantly augmented 1 day after cessation of JWH-018 treatment. Collectively, our findings show that repeated treatment with JWH-018 produces tolerance to its hypothermic and cataleptic effects, which is accompanied by transient enhancement of 5-HT1A receptor sensitivity in vivo.

  7. The value of repeating studies and multiple controls: replicated 28-day growth studies of rainbow trout exposed to clofibric acid.

    Science.gov (United States)

    Owen, Stewart F; Huggett, Duane B; Hutchinson, Thomas H; Hetheridge, Malcolm J; McCormack, Paul; Kinter, Lewis B; Ericson, Jon F; Constantine, Lisa A; Sumpter, John P

    2010-12-01

    Two studies to examine the effect of waterborne clofibric acid (CA) on growth-rate and condition of rainbow trout were conducted using accepted regulatory tests (Organisation for Economic Co-operation and Development [OECD] 215). The first study (in 2005) showed significant reductions after 21 d of exposure (21-d growth lowest-observed-effect concentration [LOEC] = 0.1 µg/L, 21-d condition LOEC = 0.1 µg/L) that continued to 28 d. Growth rate was reduced by approximately 50% (from 5.27 to 2.67% per day), while the condition of the fish reduced in a concentration-dependant manner. Additionally, in a concentration-dependent manner, significant changes in relative liver size were observed, such that increasing concentrations of CA resulted in smaller livers after 28-d exposure. A no-observed-effect concentration (NOEC) was not achieved in the 2005 study. An expanded second study (in 2006) that included a robust bridge to the 2005 study, with four replicate tanks of eight individual fish per concentration, did not repeat the 2005 findings. In the 2006 study, no significant effect on growth rate, condition, or liver biometry was observed after 21 or 28 d (28-d growth NOEC = 10 µg/L, 28-d condition NOEC = 10 µg/L), contrary to the 2005 findings. We do not dismiss either of these findings and suggest both are relevant and stand for comparison. However, the larger 2006 study carries more statistical power and multiple-tank replication, so probably produced the more robust findings. Despite sufficient statistical power in each study, interpretation of these and similar studies should be conducted with caution, because much significance is placed on the role of limited numbers of individual and tank replicates and the influence of control animals. Copyright © 2010 SETAC.

  8. Wood smoke in a controlled exposure experiment with human volunteers

    DEFF Research Database (Denmark)

    Riddervold, Ingunn Skogstad; Bønløkke, Jakob Hjort; Mølhave, Lars

    2011-01-01

    Exposure to wood smoke in the general population is increasing and concurrently, also our awareness. This article describes a wood-smoke generating system for studying human exposure to wood smoke and symptoms related to this exposure. Twenty nonsmoking atopic human participants with normal lung...... function and normal bronchial reactivity were randomly exposed for 3h at three different exposure conditions; clean filtered air (control exposure) and wood smoke with a characteristic particulate matter (PM) concentration of 200 µg/m3 (low) and 400 µg/m3 (high) under controlled environmental conditions.......0007), “irritative body perceptions” (p = 0.0127), “psychological/neurological effects” (p = 0.0075) and “weak inflammatory responses” (p = 0.0003). Furthermore, significant effects (p = 0.0192) on self-reported general mucosa irritation were found. In conclusion, exposure to wood smoke affected symptom rating...

  9. Repeated exposure to cat urine induces complex behavioral, hormonal, and c-fos mRNA responses in Norway rats ( Rattus norvegicus)

    Science.gov (United States)

    Yin, Baofa; Gu, Chen; Lu, Yi; Hegab, Ibrahim M.; Yang, Shengmei; Wang, Aiqin; Wei, Wanhong

    2017-08-01

    Prey species show specific adaptations that allow recognition, avoidance, and defense against predators. This study was undertaken to investigate the processing of a chronic, life-threatening stimulus to Norway rats ( Rattus norvegicus). One hundred forty-four Norway rats were tested by repeated presentation of cat urine for 1 h at different days in a defensive withdrawal apparatus. Rats exposed to urine for short periods showed significantly larger defensive behavioral and medial hypothalamic c-fos messenger RNA (mRNA) responses than other groups. These defensive responses habituated shortly after the presentation of cat urine. Serum levels of adrenocorticotropic hormone and corticosterone increased significantly when animals were repeatedly exposed to cat urine. However, the hormonal responses took longer to habituate than the behavioral and molecular responses did. We conclude that the behavioral and c-fos mRNA responses are "primed" for habituation to repeated exposures to cat urine, while the hormonal responses show "resistance." The results support our hypothesis that the strongest anti-predator responses at three levels would occur during short-term exposure to cat urine and that these responses would subsequently disappear on prolonged exposure. This study assists understanding the way in which the different levels of defensive responses are integrated and react during chronic stress.

  10. Realtime radiation exposure monitor and control apparatus

    International Nuclear Information System (INIS)

    Cowart, R.W.

    1981-01-01

    This patent application relates to an apparatus and methods used to obtain image information from modulation of a uniform flux. An exposure measuring apparatus is disclosed which comprises a multilayered detector structure having an external circuit connected to a transparent insulating layer and to a conductive plate a radiation source adapted to irradiate the detector structure with radiation capable of producing electron-hole pairs in a photoconductive layer of the detector wherein the flow of current within the external circuit is measured when the detector is irradiated by the radiation source. (author)

  11. Therapeutic Efficacy of Endometrial Scratching in Repeated Controlled Ovarian Stimulation (COS) Failure Cycles

    Science.gov (United States)

    Wadhwa, Leena; Mishra, Mona

    2018-01-01

    Objective: The objective of the study was (1) “to evaluate the therapeutic efficacy of endometrial scratching in repeated controlled ovarian stimulation (COS) failure cycles.” And (2) “to compare differences in pregnancy outcome by endometrial scratching in early (D2–D4) and late follicular phases (D7–D9) of the same stimulation cycle.” Materials and Methods: Women attending infertility clinic in a tertiary care center and who have two or more repeated COS failure cycles and planned for COS with intrauterine insemination (IUI) were included in the study which is a prospective parallel, interventional, single-blinded, randomized control study, in 1:1 allocation ratio. A total of 165 patients were recruited and randomly allocated into three groups: Group A (n = 55) underwent endometrial scratching on D2–D4 of the same COS cycle, Group B (n = 55) on D7–D9, and Group C (n = 55) no intervention done. All the patients underwent COS according to standard protocol followed by IUI. Results: Clinical pregnancy rate was 12.73% (odds ratio [OR] =0.87 95% confidence interval [CI] =0.288–2.55, P = 1), 16.36% (OR = 1.15; 95% CI = 0.40–3.23, P = 1), and 14.54%, respectively, in Group A, B, and C, respectively (P = 0.86), as per intention to treat analysis. Using Chi-square test, P value between Group A and B was 0.787, between Group A and C was 1.000, and between Group B and C was 1.000. As per protocol analysis, clinical pregnancy rate was 13.46% (OR = 0.83; 95% CI = 0.27–2.5, P = 0.74), 19.57% (OR = 1.3 95%; CI = 0.45–3.73, P = 0.41), and 15.69%. Using Chi-square test, Pvalue between Group A and B was 0.588, between Group A and C was 0.967, and between Group B and C was 0.815. No abortions and multiple pregnancies occurred in either of the groups. Conclusion: The effect found was of good quantum in Group B as per protocol analysis which could be of clinical relevance if larger sample size would have been taken. Endometrial scratching is a cost

  12. Effects of Single and Repeated Exposure to a 50-Hz 2-mT Electromagnetic Field on Primary Cultured Hippocampal Neurons.

    Science.gov (United States)

    Zeng, Ying; Shen, Yunyun; Hong, Ling; Chen, Yanfeng; Shi, Xiaofang; Zeng, Qunli; Yu, Peilin

    2017-06-01

    The prevalence of domestic and industrial electrical appliances has raised concerns about the health risk of extremely low-frequency magnetic fields (ELF-MFs). At present, the effects of ELF-MFs on the central nervous system are still highly controversial, and few studies have investigated its effects on cultured neurons. Here, we evaluated the biological effects of different patterns of ELF-MF exposure on primary cultured hippocampal neurons in terms of viability, apoptosis, genomic instability, and oxidative stress. The results showed that repeated exposure to 50-Hz 2-mT ELF-MF for 8 h per day after different times in culture decreased the viability and increased the production of intracellular reactive oxidative species in hippocampal neurons. The mechanism was potentially related to the up-regulation of Nox2 expression. Moreover, none of the repeated exposure patterns had significant effects on DNA damage, apoptosis, or autophagy, which suggested that ELF-MF exposure has no severe biological consequences in cultured hippocampal neurons.

  13. Biochemical and histopathological changes in the kidney and adrenal gland of rats following repeated exposure to lambda-cyhalothrin

    Directory of Open Access Journals (Sweden)

    Hassina Khaldoun Oularbi

    2014-04-01

    Full Text Available Lambda-cyhalothrin (LCT is a type II pyrethroid insecticide widely used in pest management. This study was undertaken to evaluate the toxic effects of LCT on the kidneys and adrenal glands of rats after subacute exposure. Twenty-eight 6-week-old male albino Rattus norvegicus rats were randomly assigned to four groups. Group 1 was the control group, which received distilled water. The experimental groups 2, 3 and 4 received 20.4, 30.6 and 61.2 mg/kg body weight, respectively, of LCT, administered orally over 28 days. The effects of the insecticide on various biochemical parameters were evaluated at 14 and 28 days. Histopathological studies were carried out in the kidneys and adrenal glands at the end of the experiment. Lambda-cyhalothrin, as a pyrethroid insecticide, induced significant increases (P≤0.05 in plasma urea, creatinine, uric acid and glucose concentrations, and alanine aminotransferase and aspartate aminotransferase activities after 14 and 28 days. In the rat plasma samples after 28 days, residual concentrations of LCT 1R, cis,

  14. Irritancy of antiseptics tested by repeated open exposures on the human skin, evaluated by non-invasive methods

    NARCIS (Netherlands)

    Tupker, RA; Schuur, J; Coenraads, PJ

    1997-01-01

    The aim of the study was to test the irritancy of 6 antiseptics in an open exposure model. The following agents were tested in their normal use concentrations using open exposures, 2x daily for 4 days in 20 subjects: chlorhexidine 4% (CH), chlorhexidine 0.5% in ethanol 70% (CE), ethanol 70% (ET),

  15. Effects of single and repeated exposure to biocidal active substances on the barrier function of the skin in vitro

    NARCIS (Netherlands)

    Buist, H.E.; Sandt, J.J.M. van de; Burgsteden, J.A. van; Heer, C. de

    2005-01-01

    The dermal route of exposure is important in worker exposure to biocidal products. Many biocidal active substances which are used on a daily basis may decrease the barrier function of the skin to a larger extent than current risk assessment practice addresses, due to possible skin effects of

  16. Exposure parameters in fluoroscopy equipment. Quality control

    International Nuclear Information System (INIS)

    Alonso, M.; Castaneda, M.J.; Matorras, P.; Diaz-Caneja, N.; Gutierrez, I.

    1992-01-01

    Within the quality control program in Diagnostic Radiology currently being undertaken at the 'Marques de Valdecilla' University Hospital, the corresponding specification and procedure prototypes for the control of conventional radioscopy equipment have been elaborated and applied. This paper presents the values proposed in the specifications and those obtained for the following radioscopy equipment parameters: reference kerma, and its reproducibility, kerma linearity, maximum kerma at the skin, and total filtration. The results obtained indicate that the equipment studied could comply with specified requirements if a Maintenance Program were to be implemented in coordination with the Quality Control Program. (author)

  17. Ingestion of High Molecular Weight Carbohydrate Enhances Subsequent Repeated Maximal Power: A Randomized Controlled Trial.

    Directory of Open Access Journals (Sweden)

    Jonathan M Oliver

    Full Text Available Athletes in sports demanding repeat maximal work outputs frequently train concurrently utilizing sequential bouts of intense endurance and resistance training sessions. On a daily basis, maximal work within subsequent bouts may be limited by muscle glycogen availability. Recently, the ingestion of a unique high molecular weight (HMW carbohydrate was found to increase glycogen re-synthesis rate and enhance work output during subsequent endurance exercise, relative to low molecular weight (LMW carbohydrate ingestion. The effect of the HMW carbohydrate, however, on the performance of intense resistance exercise following prolonged-intense endurance training is unknown. Sixteen resistance trained men (23±3 years; 176.7±9.8 cm; 88.2±8.6 kg participated in a double-blind, placebo-controlled, randomized 3-way crossover design comprising a muscle-glycogen depleting cycling exercise followed by ingestion of placebo (PLA, or 1.2 g•kg•bw-1 of LMW or HMW carbohydrate solution (10% with blood sampling for 2-h post-ingestion. Thereafter, participants performed 5 sets of 10 maximal explosive repetitions of back squat (75% of 1RM. Compared to PLA, ingestion of HMW (4.9%, 90%CI 3.8%, 5.9% and LMW (1.9%, 90%CI 0.8%, 3.0% carbohydrate solutions substantially increased power output during resistance exercise, with the 3.1% (90% CI 4.3, 2.0% almost certain additional gain in power after HMW-LMW ingestion attributed to higher movement velocity after force kinematic analysis (HMW-LMW 2.5%, 90%CI 1.4, 3.7%. Both carbohydrate solutions increased post-exercise plasma glucose, glucoregulatory and gut hormones compared to PLA, but differences between carbohydrates were unclear; thus, the underlying mechanism remains to be elucidated. Ingestion of a HMW carbohydrate following prolonged intense endurance exercise provides superior benefits to movement velocity and power output during subsequent repeated maximal explosive resistance exercise. This study was registered

  18. Does assessing suicidality frequently and repeatedly cause harm? A randomized control study.

    Science.gov (United States)

    Law, Mary Kate; Furr, R Michael; Arnold, Elizabeth Mayfield; Mneimne, Malek; Jaquett, Caroline; Fleeson, William

    2015-12-01

    Assessing suicidality is common in mental health practice and is fundamental to suicide research. Although necessary, there is significant concern that such assessments have unintended harmful consequences. Using a longitudinal randomized control design, the authors evaluated whether repeated and frequent assessments of suicide-related thoughts and behaviors negatively affected individuals, including those at-risk for suicide-related outcomes. Adults (N = 282), including many diagnosed with borderline personality disorder (BPD), were recruited through psychiatric outpatient clinics and from the community at large, and were randomly assigned to assessment groups. A control assessment group responded to questions regarding negative psychological experiences several times each day during a 2-week main observation phase. During the same observation period, an intensive suicide assessment group responded to the same questions, along with questions regarding suicidal behavior and ideation. Negative psychological outcomes were measured during the main observation phase (for BPD symptoms unrelated to suicide and for BPD-relevant emotions) and/or at the end of each week during the main observation phase and monthly for 6 months thereafter (for all outcomes, including suicidal ideation and behavior). Results revealed little evidence that intensive suicide assessment triggered negative outcomes, including suicidal ideation or behavior, even among people with BPD. A handful of effects did reach or approach significance, though these were temporary and nonrobust. However, given the seriousness of some outcomes, the authors recommend that researchers or clinicians who implement experience sampling methods including suicide-related items carefully consider the benefits of asking about suicide and to inform participants about possible risks. (c) 2015 APA, all rights reserved).

  19. Impact of Smoke Exposure on Digital Instrumentation and Control

    International Nuclear Information System (INIS)

    Tanaka, Tina J.; Nowlen, Steven P.; Korsah, Kofi; Wood, Richard T.; Antonescu, Christina E.

    2003-01-01

    of the chips that failed during the test recovered after enough venting.Hard disks were tested in severe environments but did not fail during the 2 h of monitoring.While the results of the tests documented in this report confirm that digital circuits can indeed be vulnerable to smoke, there is currently no practical, repeatable testing methodology, so it is not feasible to assess smoke susceptibility as part of environmental qualification. As a result, the most reasonable approach to minimizing smoke susceptibility is to employ design, implementation, and procedural practices that can reduce the possibility of smoke exposure and enhance smoke tolerance. Traditional approaches to mitigate its effects in digital safety instrumentation and control, such as redundancy, separation, defense in depth, as well as adherence to standards (e.g., the Institute of Electrical and Electronics Engineers' IEEE 384) and the Code of Federal Regulations Appendix R of 10 CFR 50, should continue to be applied

  20. Tandemly repeated sequence in 5'end of mtDNA control region of ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-12-17

    Dec 17, 2008 ... chain reaction (PCR). Japanese Spanish ... mainly covered general ecology and fishery biology. No study concerning the ... Conserved sequence blocks and the repeat units are indicated by boxes. performed using the exact ...

  1. Did I turn off the stove? Good inhibitory control can protect from influences of repeated checking

    NARCIS (Netherlands)

    Linkovski, O.; Kalanthroff, E.; Henik, A.; Anholt, G.E.

    2013-01-01

    Background and objectives: Obsessive-compulsive disorder (OCD) is an anxiety disorder characterized by compulsions aimed at reducing anxiety associated with intrusive cognitions. However, compulsive behaviors such as repeated checking were found to increase rather than decrease uncertainty related

  2. Novel CO2 laser robotic controller outperforms experienced laser operators in tasks of accuracy and performance repeatability.

    Science.gov (United States)

    Wong, Yu-Tung; Finley, Charles C; Giallo, Joseph F; Buckmire, Robert A

    2011-08-01

    To introduce a novel method of combining robotics and the CO(2) laser micromanipulator to provide excellent precision and performance repeatability designed for surgical applications. Pilot feasibility study. We developed a portable robotic controller that appends to a standard CO(2) laser micromanipulator. The robotic accuracy and laser beam path repeatability were compared to six experienced users of the industry standard micromanipulator performing the same simulated surgical tasks. Helium-neon laser beam video tracking techniques were employed. The robotic controller demonstrated superiority over experienced human manual micromanipulator control in accuracy (laser path within 1 mm of idealized centerline), 97.42% (standard deviation [SD] 2.65%), versus 85.11% (SD 14.51%), P = .018; and laser beam path repeatability (area of laser path divergence on successive trials), 21.42 mm(2) (SD 4.35 mm(2) ) versus 65.84 mm(2) (SD 11.93 mm(2) ), P = .006. Robotic micromanipulator control enhances accuracy and repeatability for specific laser tasks. Computerized control opens opportunity for alternative user interfaces and additional safety features. Copyright © 2011 The American Laryngological, Rhinological, and Otological Society, Inc.

  3. Is cosmic radiation exposure of air crew amenable to control?

    International Nuclear Information System (INIS)

    McEwan, A.C.

    1999-01-01

    ICRP Committee 4 currently has a Working Party on Cosmic Ray Exposure in Aircraft and Space Flight. It has assembled information on doses arising in aircraft and space flight and considered the appropriateness of the Commission's recommendations relating to air crew. A central issue is whether the exposures received should be considered amenable to control. Factors of relevance to the enhanced cosmic radiation exposure of air crew, and frequent fliers such as couriers, are doses to pregnant staff, the issue of controllability of doses, and the implementation of regulatory controls. It is concluded that while air crew in the current range of subsonic jet aircraft are exposed to enhanced levels of cosmic radiation, these exposures are not readily controllable nor likely to exceed about 6 mSv/y. The revised ICRP Recommendations in 1991 (ICRP 60) propose air crew be designated as occupationally exposed. However, none of the usual optimisation of dose actions associated with regulation of practices, such as classification of work areas and rules governing working procedures, can be implemented, and in practice the doses are not amenable to control. The International Basic Safety Standards therefore leave this designation to the judgement of national regulatory authorities. One requirement that stems from designation as occupational exposure is that of restriction of doses to pregnant women. Both from the points of view that it is questionable whether exposure of air crew can reasonably be considered to be amenable to control, and the magnitude of the risks from exposures incurred, there is little reason to invoke additional restrictions to limit exposures of pregnant air crew. Copyright (1999) Australasian Radiation Protection Society Inc

  4. Short-term exposure to repeated chasing stress does not induce habituation in Senegalese sole, Solea senegalensis

    DEFF Research Database (Denmark)

    Conde-Sieira, Marta; Valente, Luisa M.P.; Hernandez-Perez, Juan

    2018-01-01

    Animals can habituate to certain repeated stressors and reduce the physiological response that such stressor evoked initially. Studies related to stress habituation in fish are scarce and the available data differ depending on the species and on the type, duration and severity of the stressor...... no significant changes in serotonergic activity. However, incremented serotonergic activity was detected in fish previously trained. Furthermore, dopaminergic activity decreased in diurnal trained and nocturnal trained groups with respect to ST/naïve fish. Crh expression in hypothalamus was higher in ST...... for the animals to habituate, indicating that repeated chasing within short periods should be avoided when manipulating fish in order to keep proper welfare conditions in this species....

  5. The effect of sensory-nutrient congruency on food intake after repeated exposure: do texture and/or energy density matter?

    Science.gov (United States)

    Hogenkamp, P S

    2014-09-01

    Sensory properties guide the amount that people eat. In particular, food texture plays an important role in a food's 'expected satiation', which in turn affects the food-related decision making process. One hypothesis is that incongruent pairing of a textural cue with a post-ingestive outcome compromises this process, leading to poor energy compensation. Several studies examined the effect of both energy density and sensory characteristics (i.e. increased creaminess and thickness) on expectations, subjective appetite and food intake. To add to this literature, a re-analysis of data assessed whether the effect of sensory-nutrient pairings on energy intake compensation persisted after repeated exposure to a food. In this cross-over design, 27 participants consumed two preloads with 'congruent' (low-energy/liquid; high-energy/semi-solid) and two preloads with 'incongruent' (low-energy/semi-solid; high-energy/liquid) texture-nutrient combinations for nine subsequent meals, during which ad libitum intake was measured. Intake at first exposure did not differ between the low-energy (280±150kcal) and high-energy preloads (292±183kcal) in the incongruent conditions. By contrast, it was greater after the low-energy (332±203kcal) than after the high-energy (236±132kcal) preload in the congruent conditions (energy∗incongruent/congruent, p=0.04). Post-exposure, this pattern changed: intake depended on the energy density of the preloads in all conditions, and was greater after low-energy preloads (day∗energy∗incongruent/congruent-interaction for breakfast: p=0.02). Thus, manipulating the sensory properties of a food influenced energy compensation and meal size, but only at initial exposure. Repeated exposure 'corrected' the initial lack of compensation observed in conditions with incongruent sensory-nutrient pairings. Copyright © 2014 Elsevier Inc. All rights reserved.

  6. Narrative exposure therapy for posttraumatic stress disorder associated with repeated interpersonal trauma in patients with severe mental illness: a mixed methods design

    Directory of Open Access Journals (Sweden)

    Maria W. Mauritz

    2016-09-01

    Full Text Available Background: In the Netherlands, most patients with severe mental illness (SMI receive flexible assertive community treatment (FACT provided by multidisciplinary community mental health teams. SMI patients with comorbid posttraumatic stress disorder (PTSD are sometimes offered evidence-based trauma-focused treatment like eye movement desensitization reprocessing or prolonged exposure. There is a large amount of evidence for the effectiveness of narrative exposure therapy (NET within various vulnerable patient groups with repeated interpersonal trauma. Some FACT-teams provide NET for patients with comorbid PTSD, which is promising, but has not been specifically studied in SMI patients. Objectives: The primary aim is to evaluate NET in SMI patients with comorbid PTSD associated with repeated interpersonal trauma to get insight into whether (1 PTSD and dissociative symptoms changes and (2 changes occur in the present SMI symptoms, care needs, quality of life, global functioning, and care consumption. The second aim is to gain insight into patients’ experiences with NET and to identify influencing factors on treatment results. Methods: This study will have a mixed methods convergent design consisting of quantitative repeated measures and qualitative semi-structured in-depth interviews based on Grounded Theory. The study population will include adult SMI outpatients (n=25 with comorbid PTSD and receiving NET. The quantitative study parameters will be existence and severity of PTSD, dissociative, and SMI symptoms; care needs; quality of life; global functioning; and care consumption. In a longitudinal analysis, outcomes will be analyzed using mixed models to estimate the difference in means between baseline and repeated measurements. The qualitative study parameters will be experiences with NET and perceived factors for success or failure. Integration of quantitative and qualitative results will be focused on interpreting how qualitative results

  7. A Multifunctional Frontloading Approach for Repeated Recycling of a Pressure-Controlled AFM Micropipette.

    Directory of Open Access Journals (Sweden)

    Phillip Roder

    Full Text Available Fluid force microscopy combines the positional accuracy and force sensitivity of an atomic force microscope (AFM with nanofluidics via a microchanneled cantilever. However, adequate loading and cleaning procedures for such AFM micropipettes are required for various application situations. Here, a new frontloading procedure is described for an AFM micropipette functioning as a force- and pressure-controlled microscale liquid dispenser. This frontloading procedure seems especially attractive when using target substances featuring high costs or low available amounts. Here, the AFM micropipette could be filled from the tip side with liquid from a previously applied droplet with a volume of only a few μL using a short low-pressure pulse. The liquid-loaded AFM micropipettes could be then applied for experiments in air or liquid environments. AFM micropipette frontloading was evaluated with the well-known organic fluorescent dye rhodamine 6G and the AlexaFluor647-labeled antibody goat anti-rat IgG as an example of a larger biological compound. After micropipette usage, specific cleaning procedures were tested. Furthermore, a storage method is described, at which the AFM micropipettes could be stored for a few hours up to several days without drying out or clogging of the microchannel. In summary, the rapid, versatile and cost-efficient frontloading and cleaning procedure for the repeated usage of a single AFM micropipette is beneficial for various application situations from specific surface modifications through to local manipulation of living cells, and provides a simplified and faster handling for already known experiments with fluid force microscopy.

  8. Development of Automatic Remote Exposure Controller for Gamma Radiography

    International Nuclear Information System (INIS)

    Joo, Gwang Tae; Shin, Jin Seong; Kim, Dong Eun; Song, Jung Ho; Choo, Seung Hwan; Chang, Hong Keun

    2002-01-01

    Recently, gamma radiographic equipment have been used about 1,000 sets manually and operated by about 2,500 persons in Korea. In order for a radiography to work effectively with avoiding any hazard of the high level radiation from the source, many field workers have expected developing a wireless automatic remote exposure controller. The KlTCO research team has developed an automatic remote exposure controller that can regulate the speed of 0.4∼1.2m/s by BLDC motor of 24V 200W which has output of 54 kgf·, suitable torque and safety factor for the work. And the developed automatic remote exposure controller can control rpm of motor, pigtail position by photo-sensor and exposure time by timer to RF sensor. Thus, the developed equipment is expected that the unit can be used in many practical applications with benefits in economical advantage to combine the use of both automatic and manual type because attachment is possible existent manual remote exposure controller, AC and DC combined use

  9. The Effects of Exposure to Repeated Minor Pain During the Neonatal Period on Formalin Pain Behavior and Thermal Withdrawal Latencies

    Directory of Open Access Journals (Sweden)

    C Celeste Johnston

    2003-01-01

    Full Text Available Preterm infants undergoing untreated, repeated painful procedures as part of their early experience are more likely to behave differently to pain as they mature than infants who were born at term and did not experience excessive exogenous pain. The neonatal rat model was used to investigate the short- and long-term effects of repeated pain in infancy on later development of pain responses. Newborn rat pups were randomly assigned by litter to be left unhandled (UH, handled by being removed from the dam for 15 min four times daily (H, and being handled and receiving pain from a paw prick with a 26G needle four times daily (Pon postnatal days (PD 2 through 8 (PD2-PD8. Maternal behaviour and grooming of pups on their return to the nest were recorded at PD6 for H and P pups. At PD15, PD36 and PD65, animals were first tested for latency to thermal stimulation threshold using the Hargreaves test and then for inflammatory pain using the formalin test. Pups in the HP group received significantly more grooming from their mothers (359 s than pups in the H group (295 s, P<0.0001. When accounting for differences in maternal grooming, a decreased thermal threshold in the P group compared with the H group (6.04 s versus 5.3 s, P<0.05 was found, although the correlations were not significant between maternal grooming and thermal thresholds. No group differences were seen with the formalin test. Interestingly, age was a significant factor in both tests, with younger animals showing fewer pain behaviours regardless of group or maternal grooming of the pup. Sex was significant at one age only in latency to thermal stimulation testing. The results suggest that changes in maternal care may be an important factor mediating the long-term effects of repeated neonatal experiences of pain.

  10. Effects of acute and repeated oral exposure to the organophosphate insecticide chlorpyrifos on open-field activity in chicks.

    Science.gov (United States)

    Al-Badrany, Y M A; Mohammad, F K

    2007-11-01

    The effects of the organophosphate insecticide chlorpyrifos on 5min open-field activity were examined in a 7-15 days old chick model. Chlorpyrifos was acutely administered taking into account cholinesterase inhibition and determination of the acute (24h) median lethal dose (LD50). The oral LD50 value of chlorpyrifos in chicks was 18.14mg/kg, with cholinergic toxicosis observed on intoxicated chicks. Chlorpyrifos at the dose rates of 5,10 and 20mg/kg orally produced within 2h signs of cholinergic toxicosis in the chicks and significantly inhibited plasma (40-70%), whole brain (43-69%) and liver (31-46%) cholinesterase activities in a dose-dependent manner. Chlorpyrifos at 2 and 4mg/kg, orally did not produce overt signs of cholinergic toxicosis, but decreased (30, 60 and 90min after dosing) the general locomotor activity of the chicks as seen by a significant increase in the latency to move from the central square of the open-field arena, decreases in the numbers of lines crossed and vocalization score. Repeated daily chlorpyrifos treatments (2 and 4mg/kg, orally) for seven consecutive days also caused hypoactivity in chicks in the open-field behavioral paradigm. Only the high dose of chlorpyrifos (4mg/kg, orally) given repeatedly for 7 days caused significant cholinesterase inhibition in the whole brain (37%) and the liver (22%). In conclusion, chlorpyrifos at single or short-term repeated doses-induced behavioral changes in 7-15 days old chicks, in a model that could be used for further neurobehavioral studies involving subtle effects of organophosphates on chicks.

  11. Control of coercive field in lithium niobate crystals with repeated polarization reversal

    International Nuclear Information System (INIS)

    Ro, Jung Hoon; Jeong, Doun; Park, Taeyong; Kim, Chulhan; Kwon, Soon-Bok; Cha, Myoungsik; Choi, Byeong Cheol; Yu, Nanei; Kurimura, Sunao; Jeon, Gyerok

    2005-01-01

    In this study, the amount of decrease in coercive field of congruent lithium niobate during repeated poling and back-poling was measured. The polarization is reversed in 300 ms and then back-poled during the rest period. The coercive field can be decreased around 1 kV/mm with a repeated poling interval of 5 s. As the interval prolonged, the poling field decrease became smaller, and a stretched exponential function is suggested for the experimental fitting resulting in a set of meaningful parameters. These values are essential for the design of high quality domain engineering

  12. Identification of genomic biomarkers for anthracycline-induced cardiotoxicity in human iPSC-derived cardiomyocytes: an in vitro repeated exposure toxicity approach for safety assessment.

    Science.gov (United States)

    Chaudhari, Umesh; Nemade, Harshal; Wagh, Vilas; Gaspar, John Antonydas; Ellis, James K; Srinivasan, Sureshkumar Perumal; Spitkovski, Dimitry; Nguemo, Filomain; Louisse, Jochem; Bremer, Susanne; Hescheler, Jürgen; Keun, Hector C; Hengstler, Jan G; Sachinidis, Agapios

    2016-11-01

    The currently available techniques for the safety evaluation of candidate drugs are usually cost-intensive and time-consuming and are often insufficient to predict human relevant cardiotoxicity. The purpose of this study was to develop an in vitro repeated exposure toxicity methodology allowing the identification of predictive genomics biomarkers of functional relevance for drug-induced cardiotoxicity in human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs). The hiPSC-CMs were incubated with 156 nM doxorubicin, which is a well-characterized cardiotoxicant, for 2 or 6 days followed by washout of the test compound and further incubation in compound-free culture medium until day 14 after the onset of exposure. An xCELLigence Real-Time Cell Analyser was used to monitor doxorubicin-induced cytotoxicity while also monitoring functional alterations of cardiomyocytes by counting of the beating frequency of cardiomyocytes. Unlike single exposure, repeated doxorubicin exposure resulted in long-term arrhythmic beating in hiPSC-CMs accompanied by significant cytotoxicity. Global gene expression changes were studied using microarrays and bioinformatics tools. Analysis of the transcriptomic data revealed early expression signatures of genes involved in formation of sarcomeric structures, regulation of ion homeostasis and induction of apoptosis. Eighty-four significantly deregulated genes related to cardiac functions, stress and apoptosis were validated using real-time PCR. The expression of the 84 genes was further studied by real-time PCR in hiPSC-CMs incubated with daunorubicin and mitoxantrone, further anthracycline family members that are also known to induce cardiotoxicity. A panel of 35 genes was deregulated by all three anthracycline family members and can therefore be expected to predict the cardiotoxicity of compounds acting by similar mechanisms as doxorubicin, daunorubicin or mitoxantrone. The identified gene panel can be applied in the safety

  13. The in vitro biokinetics of chlorpromazine and diazepam in aggregating rat brain cell cultures after repeated exposure

    NARCIS (Netherlands)

    Broeders, Jessica J W; Hermens, Joop L M; Blaauboer, Bas J; Zurich, Marie-Gabrielle

    2015-01-01

    Neurotoxic effects of compounds can be tested in vitro using cell systems. One example is aggregating rat brain cell cultures. For the extrapolation of in vitro data to the in vivo situation, it is important to take the biokinetics of the test compound into account. In addition, the exposure in vivo

  14. Repeated exposure to intra-amniotic LPS partially protects against adverse effects of intravenous LPS in preterm lambs.

    Science.gov (United States)

    Gisslen, Tate; Hillman, Noah H; Musk, Gabrielle C; Kemp, Matthew W; Kramer, Boris W; Senthamaraikannan, Paranthaman; Newnham, John P; Jobe, Alan H; Kallapur, Suhas G

    2014-02-01

    Histologic chorioamnionitis, frequently associated with preterm births and adverse outcomes, results in prolonged exposure of preterm fetuses to infectious agents and pro-inflammatory mediators, such as LPS. Endotoxin tolerance-type effects were demonstrated in fetal sheep following repetitive systemic or intra-amniotic (i.a.) exposures to LPS, suggesting that i.a. LPS exposure would cause endotoxin tolerance to a postnatal systemic dose of LPS in preterm sheep. In this study, randomized pregnant ewes received either two i.a. injections of LPS or saline prior to preterm delivery. Following operative delivery, the lambs were treated with surfactant, ventilated, and randomized to receive either i.v. LPS or saline at 30  min of age. Physiologic variables and indicators of systemic and lung inflammation were measured. Intravenous LPS decreased blood neutrophils and platelets values following i.a. saline compared to that after i.a. LPS. Intra-amniotic LPS prevented blood pressure from decreasing following the i.v. LPS, but also caused an increased oxygen index. Intra-amniotic LPS did not cause endotoxin tolerance as assessed by cytokine expression in the liver, lung or plasma, but increased myeloperoxidase-positive cells in the lung. The different compartments of exposure to LPS (i.a. vs i.v.) are unique to the fetal to newborn transition. Intra-amniotic LPS incompletely tolerized fetal lambs to postnatal i.v. LPS.

  15. Intake during repeated exposure to low- and high-energy-dense yogurts by different means of consumption

    NARCIS (Netherlands)

    Hogenkamp, P.S.; Mars, M.; Stafleu, A.; Graaf, C.de

    2010-01-01

    Background: An important question in the regulation of energy intake is whether dietary learning of energy content depends on the food's characteristics, such as texture. Texture might affect the duration of sensory exposure and eating rate. Objective: The objective was to investigate whether a long

  16. Androgen receptor gene CAG repeat length as modifier of the association between Persistent Organohalogen Pollutant exposure markers and semen characteristics

    DEFF Research Database (Denmark)

    Giwercman, Aleksander; Rylander, Lars; Rignell-Hydbom, Anna

    2007-01-01

    OBJECTIVES: Exposure to persistent organohalogen pollutants was suggested to impair male reproductive function. A gene-environment interaction has been proposed. No genes modifying the effect of persistent organohalogen pollutants on reproductive organs have yet been identified. We aimed to inves...

  17. A broad-spectrum sunscreen prevents cumulative damage from repeated exposure to sub-erythemal solar ultraviolet radiation representative of temperate latitudes.

    Science.gov (United States)

    Seité, S; Christiaens, F; Bredoux, C; Compan, D; Zucchi, H; Lombard, D; Fourtanier, A; Young, A R

    2010-02-01

    We have previously shown the detrimental effects of 19 sub-erythemal exposures to daily ultraviolet radiation (DUVR, which mimics non-extreme exposure conditions), delivered over 4 weeks to volunteers. This source had UVA (320-400 nm) to UVB (290-320 nm) irradiance ratio of 25, instead of that close to 10 that is typically the case with solar-simulated radiation (SSR) that represents summer global sunlight with a clear sky and quasi-zenith solar irradiance. Here, we report on an extension of this previous study, in which we evaluated the photoprotection afforded by a broad-spectrum daily-care product with a low-sun protection factor (SPF 8, UVA-PF 7 and 3* rated UVA protection). We assessed cellular and molecular markers of photodamage that are relevant to skin cancer and photoageing. This study shows that biological effects of repeated exposure to DUVR can be prevented by a broad-spectrum daily-care product and that the level of protection afforded varies with the studied endpoint. Efficient daily UVR protection, as provided by a broad-spectrum daily-care product, is necessary to prevent the 'silent' sub-erythemal cumulative effects of UVR from inadvertent sun exposure.

  18. Determinants of repeated abortion among women of reproductive age attending health facilities in Northern Ethiopia: a case–control study

    Directory of Open Access Journals (Sweden)

    Mussie Alemayehu

    2017-02-01

    Full Text Available Abstract Background Every year, an estimated 19–20 million unsafe abortions take place, almost all in developing countries, leading to 68,000 deaths and millions more injured many permanently. Many women throughout the world, experience more than one abortion in their lifetimes. Repeat abortion is an indicator of the larger problem of unintended pregnancy. This study aimed to identify determinants of repeat abortion in Tigray Region, Ethiopia. Methods Unmatched case–control study was conducted in hospitals in Tigray Region, northern Ethiopia, from November 2014 to June 2015. The sample included 105 cases and 204 controls, recruited from among women seeking abortion care at public hospitals. Clients having two or more abortions (“repeat abortion” were taken as cases and those who had a total of one abortion were taken as controls (“single abortion”. Cases were selected consecutive based on proportional to size allocation while systematic sampling was employed for controls. Data were analyzed using SPSS version 20.0. Binary and multiple variable logistic regression analyses were calculated with 95% CI. Results Mean age of cases was 24 years (±6.85 and 22 years (±6.25 for controls. 79.0% of cases had their sexual debut in less than 18 years of age compared to 57% of controls. 42.2% of controls and 23.8% of cases cited rape as the reason for having an abortion. Study participants who did not understand their fertility cycle and when they were most likely to conceive after menstruation (adjusted odds ratio [AOR] = 2.0, 95% confidence interval [CI]: 1.1–3.7, having a previous abortion using medication (AOR = 3.3, CI: 1.83, 6.11, having multiple sexual partners in the preceding 12 months (AOR = 4.4, CI: 2.39,8.45, perceiving that the abortion procedure is not painful (AOR = 2.3, CI: 1.31,4.26, initiating sexual intercourse before the age of 18 years (AOR = 2.7, CI: 1.49, 5.23 and disclosure to a third

  19. Association between secondhand smoke exposure at home and cigarette gifting and sharing in Zhejiang, China: a repeat cross-sectional study.

    Science.gov (United States)

    Xu, Yue; Xu, ShuiYang; Wu, QingQing; Guo, YuJie

    2016-03-03

    The aims of the current study were to assess the prevalence of household cigarette gifting and sharing, and to evaluate the relationship between secondhand smoke (SHS) exposure, and cigarette gifting and sharing, in Zhejiang, China. A repeat cross-sectional design. 10 sites in 5 cities in Zhejiang, China. Two surveys were conducted with adults in Zhejiang, China, in 2010 (N=2112) and 2012 (N=2279), respectively. At both waves, the same questionnaire was used; respondents were asked questions on residence, number of family smokers, indoor smoking rules, household income and cigarette gifting and sharing. The findings revealed that more than half of respondents' families (54.50% in 2010, 52.79% in 2012) reported exposure to SHS. Many families (54.73% in 2010, 47.04% in 2012) shared cigarettes with others, and a minority (14.91% in 2010, 14.17% in 2012) reported their family giving cigarettes as a gift. There was a significant decrease in cigarette sharing from 2010 to 2012, irrespective of household with SHS exposure status; and the cigarette gifting was significantly decreased in household without SHS exposure. Compared to households without SHS exposure, the prevalence of cigarette gifting and sharing in households with SHS exposure was more obvious. Encouraging and promoting a smoke-free household environment is necessary to change public smoking customs in Zhejiang, China. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  20. Mood and autonomic responses to repeated exposure to the Trier Social Stress Test for Groups (TSST-G).

    Science.gov (United States)

    Boesch, Maria; Sefidan, Sandra; Ehlert, Ulrike; Annen, Hubert; Wyss, Thomas; Steptoe, Andrew; La Marca, Roberto

    2014-05-01

    A group version of the Trier Social Stress Test (TSST-G) was introduced as a standardized, economic and efficient tool to induce a psychobiological stress response simultaneously in a group of subjects. The aim of the present study was to examine the efficacy of the TSST-G to repeatedly induce an affective and autonomic stress response while comparing two alternative protocols for the second examination. Healthy young male recruits participated twice in the TSST-G 10 weeks apart. In the first examination, the TSST-G consisted of a combination of mental arithmetic and a fake job interview (TSST-G-1st; n=294). For the second examination, mental arithmetic was combined with either (a) a defensive speech in response to a false shoplifting accusation (TSST-G-2nd-defence; n=105), or (b) a speech on a more neutral topic selected by the investigators (TSST-G-2nd-presentation; n=100). Affect ratings and salivary alpha-amylase (sAA) were determined immediately before and after the stress test, while heart rate (HR) and heart rate variability (HRV) were measured continuously. TSST-G-1st resulted in a significant increase of negative affect, HR, and sAA, and a significant decrease in positive affect and HRV. TSST-G-2nd, overall, resulted in a significant increase of HR and sAA (the latter only in response to TSST-G-2nd-defence) and a decrease in HRV, while no significant affect alterations were found. When comparing both, TSST-G-2nd-defence and -2nd-presentation, the former resulted in a stronger stress response with regard to HR and HRV. The findings reveal that the TSST-G is a useful protocol to repeatedly evoke an affective and autonomic stress response, while repetition leads to affective but not necessarily autonomic habituation. When interested in examining repeated psychosocial stress reactivity, a task that requires an ego-involving effort, such as a defensive speech, seems to be significantly superior to a task using an impersonal speech. Copyright © 2014 Elsevier

  1. Proactive behavior, but not inhibitory control, predicts repeated innovation by spotted hyenas tested with a multi-access box.

    Science.gov (United States)

    Johnson-Ulrich, Lily; Johnson-Ulrich, Zoe; Holekamp, Kay

    2018-05-01

    Innovation is widely linked to cognitive ability, brain size, and adaptation to novel conditions. However, successful innovation appears to be influenced by both cognitive factors, such as inhibitory control, and non-cognitive behavioral traits. We used a multi-access box (MAB) paradigm to measure repeated innovation, the number of unique innovations learned across trials, by 10 captive spotted hyenas (Crocuta crocuta). Spotted hyenas are highly innovative in captivity and also display striking variation in behavioral traits, making them good model organisms for examining the relationship between innovation and other behavioral traits. We measured persistence, motor diversity, motivation, activity, efficiency, inhibitory control, and neophobia demonstrated by hyenas while interacting with the MAB. We also independently assessed inhibitory control with a detour cylinder task. Most hyenas were able to solve the MAB at least once, but only four hyenas satisfied learning criteria for all four possible solutions. Interestingly, neither measure of inhibitory control predicted repeated innovation. Instead, repeated innovation was predicted by a proactive syndrome of behavioral traits that included high persistence, high motor diversity, high activity and low neophobia. Our results suggest that this proactive behavioral syndrome may be more important than inhibitory control for successful innovation with the MAB by members of this species.

  2. Eosinophilia and biotoxin exposure in bottlenose dolphins (Tursiops truncatus) from a coastal area impacted by repeated mortality events

    International Nuclear Information System (INIS)

    Schwacke, Lori H.; Twiner, Michael J.; De Guise, Sylvain; Balmer, Brian C.; Wells, Randall S.; Townsend, Forrest I.; Rotstein, David C.; Varela, Rene A.; Hansen, Larry J.; Zolman, Eric S.; Spradlin, Trevor R.

    2010-01-01

    Bottlenose dolphins (Tursiops truncatus) inhabiting coastal waters in the northern Gulf of Mexico have been impacted by recurrent unusual mortality events over the past few decades. Several of these mortality events along the Florida panhandle have been tentatively attributed to poisoning from brevetoxin produced by the dinoflagellate Karenia brevis. While dolphins in other regions of the Florida coast are often exposed to K. brevis blooms, large-scale dolphin mortality events are relatively rare and the frequency and magnitude of die-offs along the Panhandle raise concern for the apparent vulnerability of dolphins in this region. We report results from dolphin health assessments conducted near St. Joseph Bay, Florida, an area impacted by 3 unusual die-offs within a 7-year time span. An eosinophilia syndrome, manifested as an elevated blood eosinophil count without obvious cause, was observed in 23% of sampled dolphins. Elevated eosinophil counts were associated with decreased T-lymphocyte proliferation and increased neutrophil phagocytosis. In addition, indication of chronic low-level exposure to another algal toxin, domoic acid produced by the diatom Pseudo-nitzschia spp., was determined. Previous studies of other marine mammal populations exposed recurrently to Pseudo-nitzschia blooms have suggested a possible link between the eosinophilia and domoic acid exposure. While the chronic eosinophilia syndrome could over the long-term produce organ damage and alter immunological status and thereby increase vulnerability to other challenges, the significance of the high prevalence of the syndrome to the observed mortality events in the St. Joseph Bay area is unclear. Nonetheless, the unusual immunological findings and concurrent evidence of domoic acid exposure in this sentinel marine species suggest a need for further investigation to elucidate potential links between chronic, low-level exposure to algal toxins and immune health.

  3. Eosinophilia and biotoxin exposure in bottlenose dolphins (Tursiops truncatus) from a coastal area impacted by repeated mortality events

    Energy Technology Data Exchange (ETDEWEB)

    Schwacke, Lori H., E-mail: Lori.Schwacke@noaa.gov [National Oceanic and Atmospheric Administration, National Ocean Service, Center for Human Health Risks, 331 Fort Johnson Road, Charleston, SC 29412 (United States); Twiner, Michael J. [National Oceanic and Atmospheric Administration, National Ocean Service, Center for Coastal Environmental Health and Biomolecular Research, 219 Fort Johnson Road, Charleston, SC 29412 (United States); De Guise, Sylvain [University of Connecticut, Department of Pathobiology and Veterinary Science, 61 North Eagleville Road, U-89, Storrs, CT 06269 (United States); Balmer, Brian C.; Wells, Randall S. [Chicago Zoological Society, c/o Mote Marine Laboratory, 1600 Ken Thompson Parkway, Sarasota, FL 34236 (United States); Townsend, Forrest I. [Bayside Hospital for Animals, 251 N.E. Racetrack Road, Fort Walton Beach, FL 32547 (United States); Rotstein, David C. [National Oceanic and Atmospheric Administration, National Marine Fisheries Service, Office of Protected Resources, Marine Mammal Health and Stranding Response Program, 1315 East West Highway, Silver Spring, MD 20910 (United States); Varela, Rene A. [Ocean Embassy Inc, 6433 Pinecastle Blvd, Ste 2, Orlando, FL 32809 (United States); Hansen, Larry J. [National Oceanic and Atmospheric Administration, National Marine Fisheries Service Southeast Fisheries Science Center,101 Pivers Island Road, Beaufort, NC 28516 (United States); Zolman, Eric S. [National Oceanic and Atmospheric Administration, National Ocean Service, Center for Coastal Environmental Health and Biomolecular Research, 219 Fort Johnson Road, Charleston, SC 29412 (United States); Spradlin, Trevor R. [National Oceanic and Atmospheric Administration, National Marine Fisheries Service, Office of Protected Resources, Marine Mammal Health and Stranding Response Program, 1315 East West Highway, Silver Spring, MD 20910 (United States); and others

    2010-08-15

    Bottlenose dolphins (Tursiops truncatus) inhabiting coastal waters in the northern Gulf of Mexico have been impacted by recurrent unusual mortality events over the past few decades. Several of these mortality events along the Florida panhandle have been tentatively attributed to poisoning from brevetoxin produced by the dinoflagellate Karenia brevis. While dolphins in other regions of the Florida coast are often exposed to K. brevis blooms, large-scale dolphin mortality events are relatively rare and the frequency and magnitude of die-offs along the Panhandle raise concern for the apparent vulnerability of dolphins in this region. We report results from dolphin health assessments conducted near St. Joseph Bay, Florida, an area impacted by 3 unusual die-offs within a 7-year time span. An eosinophilia syndrome, manifested as an elevated blood eosinophil count without obvious cause, was observed in 23% of sampled dolphins. Elevated eosinophil counts were associated with decreased T-lymphocyte proliferation and increased neutrophil phagocytosis. In addition, indication of chronic low-level exposure to another algal toxin, domoic acid produced by the diatom Pseudo-nitzschia spp., was determined. Previous studies of other marine mammal populations exposed recurrently to Pseudo-nitzschia blooms have suggested a possible link between the eosinophilia and domoic acid exposure. While the chronic eosinophilia syndrome could over the long-term produce organ damage and alter immunological status and thereby increase vulnerability to other challenges, the significance of the high prevalence of the syndrome to the observed mortality events in the St. Joseph Bay area is unclear. Nonetheless, the unusual immunological findings and concurrent evidence of domoic acid exposure in this sentinel marine species suggest a need for further investigation to elucidate potential links between chronic, low-level exposure to algal toxins and immune health.

  4. Sticky situations: cyanoacrylate exposures reported to a poison control system.

    Science.gov (United States)

    Carstairs, Shaun D; Koh, Cynthia; Qian, Lily; Qozi, Mariam; Seivard, Grant; Cantrell, F Lee

    2017-11-01

    Cyanoacrylate (Super Glue ® ) exposures are commonly reported to poison control centers, but little has been published in the medical literature regarding these exposures. We sought to characterize cyanoacrylate exposures reported to a poison control system. We performed a retrospective review of a poison system's database for all cases of single-substance human exposure to cyanoacrylate-containing products from 2005 to 2015. Data collected included age, gender, route of exposure, clinical effects, treatments recommended and medical outcome. There were a total of 893 patients, 505 (56.6%) of which were female. Patient ages ranged from 6 months to 88 years with a median of 11 years. The vast majority of exposures (n = 871, 97.5%) were unintentional, but a small number of exposures (n = 22, 2.5%) were due to intentional misuse (such as trying to stop a bleeding cut) or malicious intent (such as purposefully gluing a person's eyes shut as a prank). Routes of exposure included: ingestion, n = 337 (37.7%); ocular, n = 322 (36.1%); dermatologic, n = 285 (31.9%); inhalation, n = 16 (1.8%); nasal, n = 1 (0.1%); and otic, n = 1 (0.1%); some patients had multiple routes of exposure. Treatments recommended by the poison center included irrigation (n = 411), petroleum jelly (n = 143), mineral oil (n = 131), topical antibiotic ointment (n = 82), peanut butter (n = 6), acetone (n = 4) and WD-40 ® (n = 2). A total of 657 patients (73.6%) were managed on-site, while 236 (26.4%) were seen in a health care facility. Among all exposures, effects were classified as none (n = 287), minor (n = 529) and moderate (n = 77). No major effects or deaths were reported. In this case series, the majority of cases occurred in children and most exposures did not result in significant morbidity. Notably, there was wide variation in terms of recommended treatments; further study is needed to determine the optimal treatment

  5. Repeated exposure to methamphetamine induces sex-dependent hypersensitivity to ischemic injury in the adult rat heart.

    Directory of Open Access Journals (Sweden)

    Boyd R Rorabaugh

    Full Text Available We previously reported that adult female, but not male rats that were prenatally exposed to methamphetamine exhibit myocardial hypersensitivity to ischemic injury. However, it is unknown whether hypersensitivity to ischemic injury develops when rats are exposed to methamphetamine during adulthood. The goal of this study was to determine whether methamphetamine exposure during adulthood sensitizes the heart to ischemic injury.Adult male and female rats received daily injections of methamphetamine (5 mg/kg or saline for 10 days. Their hearts were isolated on day 11 and subjected to a 20 min ischemic insult on a Langendorff isolated heart apparatus. Cardiac contractile function was measured by an intraventricular balloon, and infarct size was measured by triphenyltetrazolium chloride staining.Hearts from methamphetamine-treated females exhibited significantly larger infarcts and suppressed postischemic recovery of contractile function compared to hearts from saline-treated females. In contrast, methamphetamine had no effect on infarct size or contractile recovery in male hearts. Subsequent experiments demonstrated that hypersensitivity to ischemic injury persisted in female hearts following a 1 month period of abstinence from methamphetamine. Myocardial protein kinase C-ε expression, Akt phosphorylation, and ERK phosphorylation were unaffected by adult exposure to methamphetamine.Exposure of adult rats to methamphetamine sex-dependently increases the extent of myocardial injury following an ischemic insult. These data suggest that women who have a heart attack might be at risk of more extensive myocardial injury if they have a recent history of methamphetamine abuse.

  6. Repeated exposure to methamphetamine induces sex-dependent hypersensitivity to ischemic injury in the adult rat heart

    Science.gov (United States)

    Seeley, Sarah L.; Stoops, Thorne S.; D’Souza, Manoranjan S.

    2017-01-01

    Background We previously reported that adult female, but not male rats that were prenatally exposed to methamphetamine exhibit myocardial hypersensitivity to ischemic injury. However, it is unknown whether hypersensitivity to ischemic injury develops when rats are exposed to methamphetamine during adulthood. The goal of this study was to determine whether methamphetamine exposure during adulthood sensitizes the heart to ischemic injury. Methods Adult male and female rats received daily injections of methamphetamine (5 mg/kg) or saline for 10 days. Their hearts were isolated on day 11 and subjected to a 20 min ischemic insult on a Langendorff isolated heart apparatus. Cardiac contractile function was measured by an intraventricular balloon, and infarct size was measured by triphenyltetrazolium chloride staining. Results Hearts from methamphetamine-treated females exhibited significantly larger infarcts and suppressed postischemic recovery of contractile function compared to hearts from saline-treated females. In contrast, methamphetamine had no effect on infarct size or contractile recovery in male hearts. Subsequent experiments demonstrated that hypersensitivity to ischemic injury persisted in female hearts following a 1 month period of abstinence from methamphetamine. Myocardial protein kinase C-ε expression, Akt phosphorylation, and ERK phosphorylation were unaffected by adult exposure to methamphetamine. Conclusions Exposure of adult rats to methamphetamine sex-dependently increases the extent of myocardial injury following an ischemic insult. These data suggest that women who have a heart attack might be at risk of more extensive myocardial injury if they have a recent history of methamphetamine abuse. PMID:28575091

  7. Potential for the development of tolerance by Aspergillus amstelodami, A. repens and A. ruber after repeated exposure to potassium sorbate.

    Science.gov (United States)

    Viñas, I; Morlans, I; Sanchis, V

    1990-01-01

    Three strains of A. amstelodami, A. repens and A. ruber were exposed to various levels of potassium sorbate, and the MICs were determined. Selected strains of the molds were then repeatedly exposed to subinhibitory levels of the compound to determine whether increased tolerance might develop. The MIC of sorbate (pH 5.5 or 6.5) for 3 species of Aspergillus was 0.07%. Increasing levels of sorbate resulted in increasing growth suppression of the molds. The 3 Aspergillus species were tested for increased tolerance to potassium sorbate, and none was found. They developed a slight increase in tolerance dependent upon pH and the mold strain by subculturing at low levels of sorbate.

  8. Comparative study of the pharmacokinetics of carbon tetrachloride in the rat following repeated inhalation exposures of 8 and 11.5 hr/day

    International Nuclear Information System (INIS)

    Paustenbach, D.J.; Carlson, G.P.; Christian, J.E.; Born, G.S.

    1986-01-01

    To evaluate whether exposure to inhaled vapors for periods longer than 8 hr/day could affect the rates and routes of elimination, male Sprague-Dawley rats were repeatedly exposed to 100 ppm of radiolabeled carbon tetrachloride ( 14 CCl 4 ) in a closed-loop chamber. One group was exposed for 8 hr/day for 5 days and another group for 11.5 hr/day for 4 days. Two other groups were exposed for either 8 hr/day for 10 of 12 consecutive days or 11.5 hr/day for 7 of 10 days. The elimination of 14 C activity was measured in the expired air, urine, and feces for up to 100 hr following exposure and the pharmacokinetic parameters were determined. Following 2 weeks of exposure to the 8-hr/day schedule, 14 CCl 4 in the breath and 14 C activity in the feces comprised 45 and 48% of the total 14 C excreted, respectively. Following 2 weeks of exposure to the 11.5-hr/day schedule, the values were 32 and 62%, respectively, indicating that repeated exposure to the longer schedule altered the route of elimination of CCl 4 . Regardless of the period of exposure, less than 8% of the inhaled 14 CCl 4 was excreted in the urine and less than 2% was exhaled in the breath as the 14 CO 2 metabolite. Approximately 97-98% of the 14 C activity in the expired air was 14 CCl 4 . The quantities of 14 C noted in the feces and urine suggest that more than 60% of the inhaled CCl 4 was metabolized. Elimination of 14 CCl 4 and 14 CO 2 in the breath followed a two-compartment, first-order pharmacokinetic model (r2 = 0.98). For rats exposed 8 hr/day and 11.5 hr/day for 2 weeks, the average half-lives for elimination of 14 CCl 4 in the breath for the fast (alpha) and slow (beta) phases averaged 96 and 455 min, and 89 and 568 min, respectively. The average alpha and beta half-lives for elimination of 14 CO 2 in the breath

  9. Laboratory electron exposure of TSS-1 thermal control coating

    Science.gov (United States)

    Vaughn, J. A.; Mccollum, M.; Carruth, M. R., Jr.

    1995-01-01

    RM400, a conductive thermal control coating, was developed for use on the exterior shell of the tethered satellite. Testing was performed by the Engineering Physics Division to quantify effects of the space environment on this coating and its conductive and optical properties. Included in this testing was exposure of RM400 to electrons with energies ranging from 0.1 to 1 keV, to simulate electrons accelerated from the ambient space plasma when the tethered satellite is fully deployed. During this testing, the coating was found to luminesce, and a prolonged exposure of the coating to high-energy electrons caused the coating to darken. This report describes the tests done to quantify the degradation of the thermal control properties caused by electron exposure and to measure the luminescence as a function of electron energy and current density to the satellite.

  10. Performance of bias-correction methods for exposure measurement error using repeated measurements with and without missing data.

    Science.gov (United States)

    Batistatou, Evridiki; McNamee, Roseanne

    2012-12-10

    It is known that measurement error leads to bias in assessing exposure effects, which can however, be corrected if independent replicates are available. For expensive replicates, two-stage (2S) studies that produce data 'missing by design', may be preferred over a single-stage (1S) study, because in the second stage, measurement of replicates is restricted to a sample of first-stage subjects. Motivated by an occupational study on the acute effect of carbon black exposure on respiratory morbidity, we compare the performance of several bias-correction methods for both designs in a simulation study: an instrumental variable method (EVROS IV) based on grouping strategies, which had been recommended especially when measurement error is large, the regression calibration and the simulation extrapolation methods. For the 2S design, either the problem of 'missing' data was ignored or the 'missing' data were imputed using multiple imputations. Both in 1S and 2S designs, in the case of small or moderate measurement error, regression calibration was shown to be the preferred approach in terms of root mean square error. For 2S designs, regression calibration as implemented by Stata software is not recommended in contrast to our implementation of this method; the 'problematic' implementation of regression calibration although substantially improved with use of multiple imputations. The EVROS IV method, under a good/fairly good grouping, outperforms the regression calibration approach in both design scenarios when exposure mismeasurement is severe. Both in 1S and 2S designs with moderate or large measurement error, simulation extrapolation severely failed to correct for bias. Copyright © 2012 John Wiley & Sons, Ltd.

  11. Decreased extracellular adenosine levels lead to loss of hypoxia-induced neuroprotection after repeated episodes of exposure to hypoxia.

    Directory of Open Access Journals (Sweden)

    Mei Cui

    Full Text Available Achieving a prolonged neuroprotective state following transient ischemic attacks (TIAs is likely to effectively reduce the brain damage and neurological dysfunction associated with recurrent stroke. HPC is a phenomenon in which advanced exposure to mild hypoxia reduces the stroke volume produced by a subsequent TIA. However, this neuroprotection is not long-lasting, with the effects reaching a peak after 3 days. Therefore, in this study, we investigated the use of multiple episodes of hypoxic exposure at different time intervals to induce longer-term protection in a mouse stroke model. C57BL/6 mice were subjected to different hypoxic preconditioning protocols: a single episode of HPC or five identical episodes at intervals of 3 days (E3d HPC or 6 days (E6d HPC. Three days after the last hypoxic exposure, temporary middle cerebral artery occlusion (MCAO was induced. The effects of these HPC protocols on hypoxia-inducible factor (HIF regulated gene mRNA expression were measured by quantitative PCR. Changes in extracellular adenosine concentrations, known to exert neuroprotective effects, were also measured using in vivo microdialysis and high pressure liquid chromatography (HPLC. Neuroprotection was provided by E6d HPC but not E3d HPC. HIF-regulated target gene expression increased significantly following all HPC protocols. However, E3d HPC significantly decreased extracellular adenosine and reduced cerebral blood flow in the ischemic region with upregulated expression of the adenosine transporter, equilibrative nucleoside transporter 1 (ENT1. An ENT1 inhibitor, propentofylline increased the cerebral blood flow and re-established neuroprotection in E3d HPC. Adenosine receptor specific antagonists showed that adenosine mainly through A1 receptor mediates HPC induced neuroprotection. Our data indicate that cooperation of HIF-regulated genes and extracellular adenosine is necessary for HPC-induced neuroprotection.

  12. Prevention of diabetes in NOD mice by repeated exposures to a contact allergen inducing a sub-clinical dermatitis

    DEFF Research Database (Denmark)

    Engkilde, Kaare; Buschard, Karsten; Hansen, Axel Jacob Kornerup

    2010-01-01

    Type 1 diabetes is an autoimmune disease, while allergic contact dermatitis although immune mediated, is considered an exposure driven disease that develops due to epicutaneous contact with reactive low-molecular chemicals. The objective of the present study was to experimentally study the effect...... of contact allergens on the development of diabetes in NOD mice. As the link between contact allergy and diabetes is yet unexplained we also examined the effect of provocation with allergens on Natural Killer T (NKT) cells, since involvement of NKT cells could suggest an innate connection between the two...

  13. Assessment of arsenic exposures and controls in gallium arsenide production.

    Science.gov (United States)

    Sheehy, J W; Jones, J H

    1993-02-01

    The electronics industry is expanding the use of gallium arsenide in the production of optoelectronic devices and integrated circuits. Workers in the electronics industry using gallium arsenide are exposed to hazardous substances such as arsenic, arsine, and various acids. Arsenic requires stringent controls to minimize exposures (the current OSHA PEL for arsenic is 10 micrograms/m3 and the NIOSH REL is 2 micrograms/m3 ceiling). Inorganic arsenic is strongly implicated in respiratory tract and skin cancer. For these reasons, NIOSH researchers conducted a study of control systems for facilities using gallium arsenide. Seven walk-through surveys were performed to identify locations for detailed study which appeared to have effective controls; three facilities were chosen for in-depth evaluation. The controls were evaluated by industrial hygiene sampling. Including personal breathing zone and area air sampling for arsenic and arsine; wipe samples for arsenic also were collected. Work practices and the use of personal protective equipment were documented. This paper reports on the controls and the arsenic exposure results from the evaluation of the following gallium arsenide processes: Liquid Encapsulated Czochralski (LEC) and Horizontal Bridgeman (HB) crystal growing, LEC cleaning operations, ingot grinding/wafer sawing, and epitaxy. Results at one plant showed that in all processes except epitaxy, average arsenic exposures were at or above the OSHA action level of 5 micrograms/m3. While cleaning the LEC crystal pullers, the average potential arsenic exposure of the cleaning operators was 100 times the OSHA PEL. At the other two plants, personal exposures for arsenic were well controlled in LEC, LEC cleaning, grinding/sawing, and epitaxy operations.

  14. Leptospira Exposure and Gardeners: A Case-Control Seroprevalence Study

    Science.gov (United States)

    Alvarado-Esquivel, Cosme; Hernandez-Tinoco, Jesus; Sanchez-Anguiano, Luis Francisco; Ramos-Nevarez, Agar; Cerrillo-Soto, Sandra Margarita; Guido-Arreola, Carlos Alberto

    2016-01-01

    Background Leptospira can be found in soil. However, it is unclear whether occupational exposure to soil may represent a risk for Leptospira infection in humans. Therefore, we sought to determine the association of Leptospira IgG seroprevalence with the occupation of gardener, and to determine the epidemiological characteristics of gardeners associated with Leptospira exposure. Methods We performed a case-control study in 168 gardeners and 168 age- and gender-matched control subjects without gardening occupation in Durango City, Mexico. The seroprevalence of anti-Leptospira IgG antibodies in cases and controls was determined using an enzyme immunoassay. Bivariate and multivariate analyses were used to assess the association of Leptospira exposure and the characteristics of the gardeners. Results Anti-Leptospira IgG antibodies were found in 10 (6%) of 168 gardeners and in 15 (8.9%) of 168 control subjects (odds ratio (OR): 0.64; 95% confidence interval (CI): 0.28 - 1.48; P = 0.40). Multivariate analysis showed that Leptospira seropositivity was positively associated with female gender (OR: 5.82; 95% CI: 1.11 - 30.46; P = 0.03), and negatively associated with eating while working (OR: 0.21; 95% CI: 0.05 - 0.87; P = 0.03). In addition, multivariate analysis showed that high anti-Leptospira levels were associated with consumption of boar meat (OR: 28.00; 95% CI: 1.20 - 648.80; P = 0.03). Conclusions This is the first case-control study of Leptospira exposure in gardeners. Results do not support an association of Leptospira exposure with the occupation of gardener. However, further studies to confirm the lack of this association are needed. The potential role of consumption of boar meat in Leptospira infection deserves further investigation. PMID:26668679

  15. The preventive effect of vitamin C on the cellular and functional integrity of kidney cells in rats following repeated exposure to paraquat

    Directory of Open Access Journals (Sweden)

    Benjamin Nnamdi Okolonkwo

    2014-11-01

    Full Text Available Paraquat (PQ is a bipyridylium herbicide that is applied around trees in orchards and between crop rows to control broad-leaved and grassy weeds. Its oxidation results in the formation of superoxides which causes damage to cellular components. In this study, we determined the antioxidant effect vitamin C has on the cellular integrity of kidney function in rats following repeated exposure to PQ. Ninety-six male rats, grouped twelve rats per subgroup (A, Avit.c, B, Bvit.c, C, Cvit.c, D and Dvit.c were intraperitoneally injected with different sublethal increasing doses (0, 0, 2, 2, 4, 4, 6 and 6 mg/kg body weight of PQ respectively on biweekly (14 days intervals over a period of three months (84 days. Subsequently, the subgrouped animals (Avit.c, Bvit.c, Cvit.c and Dvit.c were maintained orally with 1 g/L vitamin C, while the other subgrouped animals (A, B, C and D received drinking water with negligible vitamin content throughout the study period. At the end of each monthly (28 days treatment, four animals per subgroup were selected. Urine samples were collected from each of the selected rats, after which each of the animals were anaesthetized with gaseous isoflurane and 5 mL of blood samples were collected using cardiac puncture procedure. The animals were later decapitated and their kidneys harvested. The samples collected were analyzed for urine [specific gravity (SG, pH, protein and glucose], blood (urea, creatinine, total protein and glucose, and the histological studies on kidney slides. The dose and exposure- time dependent PQ toxicity resulted in the reduction in urinary pH, elevation in urinary SG, and the detectable presence of protein and glucose in urine. It also caused marked elevation in serum urea and creatinine levels with reduction in serum protein and glucose levels and alterations in the cellular integrity of the renal architecture, especially the glomeruli and tubular tissues. Treatments on the PQ insulted animals with vitamin

  16. Toxicological evaluation of silver nanoparticles and silver nitrate in rats following 28 days of repeated oral exposure.

    Science.gov (United States)

    Qin, Guangqiu; Tang, Song; Li, Shibin; Lu, Haoliang; Wang, Yanwu; Zhao, Peng; Li, Bin; Zhang, Jiehong; Peng, Liang

    2017-02-01

    The increasing application of silver nanoparticles (AgNPs) has been raising concerns about their potential adverse effects to human and the environment. However, the knowledge on the systemic toxicity of AgNPs in mammalian systems is still limited. The present study investigated the toxicity of PVP-coated AgNPs in rats treated with repeated oral administration, and compared that with equivalent dose of AgNO 3 . Specifically, one hundred male and female rats were orally administrated with particulate or ionic forms of silver (Ag) separately at doses of 0.5 and 1 mg kg -1 body weight daily for 28 days. The results reveal no significant toxic effects of AgNPs and AgNO 3 up to 1 mg kg -1 body weight, with respect to the body weight, organ weight, food intake, and histopathological examination. Ag distribution pattern in organs of rats treated with AgNPs was similar to that of AgNO 3 treated rats, showing liver and kidneys are the main target organs followed by testis and spleen. The total Ag contents in organs were significantly lower in the AgNPs treated rats than those in the AgNO 3 treated rats. However, the comparisons between AgNPs and AgNO 3 treatments further indicated more potent of AgNPs in biochemical and hematological parameters in rats, including red blood cell count (RBC), platelet count (PLT), white blood cell count (WBC) and aspartate transaminase (AST). Results of this study suggested that particulate Ag at least partially contributed to the observed toxicity of AgNPs, and both ionic and particulate Ag should be taken into consideration in toxicological evaluation of AgNPs. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 609-618, 2017. © 2016 Wiley Periodicals, Inc.

  17. Development of immunity against viral and bacterial antigens after repeated exposures to suberythemal doses of ultraviolet light

    Directory of Open Access Journals (Sweden)

    S. A. Snopov

    2012-01-01

    Full Text Available The effects of ultraviolet (UV radiation on human infectious immunity are not well studied. On the one hand, solar and artificial UU sources have been shown to change cytokine levels in human skin, lymphocyte subpopulation counts in parepheral blood, lymphocyte DNA synthesis and prolifarative response to mitogens. On the other hand, there are just only one or two observations suggesting an influence of UV radiation on human infection course. For instance, UV irradiations have been reported to induce a reccurence of orofacial vesicular lesions caused by herpes siplex virus. Moreover, there is a lack of data concerning immune effects of suberythtemal doses of UV in spite of a long history of using them by Russian prophylactic medicine. In this work we questioned whether such suberythemal UV exposures can affect the immune responses of children to infectious conjunctivitis, to simultaneous measles and polio vaccinations and to simultaneous polio and diphtheria-tetanus vaccinations. In peripheral blood of vaccinated children we examined leukocyte counts (monocytes, neutrophils, eosinophils, lymphocytes, percentages of lymphocyte subpopulations (CD3+, CD20+, CD4+, CD8+, CD25+, HLADR+, concentrations of cytokines (IL-1 beta, TNF-alpha, IFN- amma и IL-10, DNA-synthetic activity of lymphocytes and titres of antibodies against measles and diphtheria toxin. We observed no local or systemic reactions to the vaccines in the UV-group while a moderate rise in body temperature occured in several children from unexposed group. In the blood of childeren from UV-group we found increases in CD25+ и HLADR+ cell percentages, IL- 1 beta and IL-10 concentrations, PWMinduced DNA synthesis in mononuclears, and no decreases in formation of antibodies against measles and diphreria. We concluded that suberythemal UV exposures of children modulated their further responses to imminisations perhaps through the activation of a T helper 2-like

  18. The radiation exposure control programme - its effect on design

    International Nuclear Information System (INIS)

    Simmons, R.B.V.

    1975-01-01

    The paper discusses how the Power Projects design organization has responded to the problem of operational exposure. This response took the form of an organized formal Programme developed during the Bruce G.S. design phase. This Radiation Exposure Control Programme considered: radiation conditions, number of items requiring attention, number of occasions item requires attention and manhours involved on each occasion. Analysis of these factors and comparison with target values enabled worthwhile reductions to be made in estimated operating exposure. Activity transport studies, reliability and design detail improvements have all received an impetus from the Programme. The Programme which has value both from the economic and the health physics points of view is now a continuing feature of the CANDU plant design process. (author)

  19. Electronic device for automatic control of exposure in radiography

    International Nuclear Information System (INIS)

    Pendharkar, A.S.; Jayakumar, T.K.

    1977-01-01

    An electronic instrument for calculating and controlling exposure in radiography practice using radioisotopes is described. When using this equipment, only factor to be known is the dose required by the film for a given density and the thickness of material inspected. It eliminates all the problems arising out of various parameters such as source decay etc in the conventional procedure for calculating exposure time. Principle of operation, the electronic circuitry adopted and the functional aspects of the system are described in detail. Exposure doses for different industrial films have been related to the instrumental readouts. The system reproducibility and reliability have been evaluated. The advantages and limitations of the present system and the future development to overcome the problems are indicated. (author)

  20. The rate of repeating X-rays in the medical centers of Jenin District/Palestine and how to reduce patient exposure to radiation

    Science.gov (United States)

    Assi, Abed Al Nasser

    2018-03-01

    Reduction of the patient's received radiation dose to as low as reasonably achievable (ALARA) is based on recommendations of radiation protection organizations such as the International Commission on Radiological Protection (ICRP) and the National Radiological Protection Board (NRPB). The aim of this study was to explore the frequency and characteristics of rejected / repeated radiographic films in governmental and private centers in Jenin city. The radiological centers were chosen based on their high volume of radiographic studies. The evaluation was carried out over a period of four months. The collected data were compiled at the end of each week and entered into a computer for analysis at the end of study. Overall 5000 films (images) were performed in four months, The average repeat rate of radiographic images was 10% (500 films). Repetition rate was the same for both thoracic and abdominal images (42%). The main reason for repeating imaging was inadequate imaging quality (58.2%) and poor film processing (38%). Human error was the most likely reason necessitating the repetition of the radiographs (48 %). Infant and children groups comprised 85% of the patient population that required repetition of the radiographic studies. In conclusion, we have a higher repetition rate of imaging studies compared to the international standards (10% vs. 4-6%, respectively). This is especially noticeable in infants and children, and mainly attributed to human error in obtaining and processing images. This is an important issue that needs to be addressed on a national level due to the ill effects associated with excessive exposure to radiation especially in children, and to reduce cost of the care delivered.

  1. Disposition of Lead (Pb) in Saliva and Blood of Sprague-Dawley Rats Following a Single or Repeated Oral Exposure to Pb-Acetate

    Energy Technology Data Exchange (ETDEWEB)

    Timchalk, Chuck; Lin, Yuehe; Weitz, Karl K.; Wu, Hong; Gies, Richard A.; Moore, Dean A.; Yantasee, Wassana

    2006-05-01

    Biological monitoring for lead (Pb) is usually based upon a determination of blood Pb concentration; however, saliva has been suggested as a non-invasive biological matrix for assessing exposure. To further evaluate the potential utility of saliva for biomonitoring, the disposition of Pb was evaluated in whole blood (WB), red blood cells (RBC), plasma, parotid gland, bone, and saliva following either a single oral dose of 100 mg Pb-acetate/kg body weight in rats or {approx}1-week after 5 sequential daily oral gavage doses of 1, 10, or 100 mg Pb-acetate/kg/day. Saliva volume, pH, total saliva protein, and ?-amylase activity were also determined. At specified times post-dosing groups of animals were anethetized and administered pilocarpine to induce salivation. Saliva was collected, the animals were humanely sacrificed, and tissue samples were likewise collected, weighed, and processed for Pb analysis. Following a single dose exposure to PB-acetate, Pb was detectable in all samples by 30 min post-dosing. For both the single and repeated dose treatments the concentration of Pb was highest in WB and RBC relative to plasma and saliva. However, the Pb rapidly redistributed (within 5-days post-treatment) from the blood into the bone compartment based on the substantial decrease in WB and RBC Pb concentration, and the concurrent increase in bone Pb following repeated exposure at all dose levels. Although there is clear variability in the observed Pb concentrations in plasma and saliva, there was a reasonable correlation (r2=0.922) between the average Pb concentrations in these biological matrices which was consistent with previous observations. The single oral dose of Pb-acetate resulted in a decrease in salivary pH which recovered by 24 hr post-dosing and a decrease in ?-amylase enzyme activity which did recover within 5-days of ceasing exposure. It is currently unclear what impact these slight functional changes may or may not have on Pb salivary clearance rates. These

  2. Nano-metal oxides: Exposure and engineering control assessment.

    Science.gov (United States)

    Garcia, Alberto; Eastlake, Adrienne; Topmiller, Jennifer L; Sparks, Christopher; Martinez, Kenneth; Geraci, Charles L

    2017-09-01

    In January 2007, the National Institute for Occupational Safety and Health (NIOSH) conducted a field study to evaluate process specific emissions during the production of ENMs. This study was performed using the nanoparticle emission assessment technique (NEAT). During this study, it was determined that ENMs were released during production and cleaning of the process reactor. Airborne concentrations of silver, nickel, and iron were found both in the employee's personal breathing zone and area samples during reactor cleaning. At the completion of this initial survey, it was suggested that a flanged attachment be added to the local exhaust ventilation system.  NIOSH re-evaluated the facility in December 2011 to assess worker exposures following an increase in production rates. This study included a fully comprehensive emissions, exposure, and engineering control evaluation of the entire process. This study made use of the nanoparticle exposure assessment technique (NEAT 2.0). Data obtained from filter-based samples and direct reading instruments indicate that reactor cleanout increased the overall particle concentration in the immediate area. However, it does not appear that these concentrations affect areas outside of the production floor. As the distance between the reactor and the sample location increased, the observed particle number concentration decreased, creating a concentration gradient with respect to the reactor. The results of this study confirm that the flanged attachment on the local exhaust ventilation system served to decrease exposure potential.  Given the available toxicological data of the metals evaluated, caution is warranted. One should always keep in mind that occupational exposure levels were not developed specifically for nanoscale particles. With data suggesting that certain nanoparticles may be more toxic than the larger counterparts of the same material; employers should attempt to control emissions of these particles at the source

  3. Analgesia induced by repeated exposure to low dose X-rays in mice, and involvement of the accessory olfactory system in modulation of the radiation effects

    International Nuclear Information System (INIS)

    Miyachi, Yukihisa; Yamada, Takeshi

    1997-01-01

    The effects of low-dose X-rays on mouse nociceptive behavior were examined using a formalin injected test which rated the amount of time the animals spent licking the injected hind-paw. Male ICR White Swiss mice showed a marked suppression of licking behavior after repeated low-dose X-irradiation (5 cGy/day, 6 consecutive days). The most profound effect was observed on the day 30 after irradiation. The decline of licking behavior, however, was not observed at all following olfactory bulbectomy or vomeronasal tract cut. The analgesic effects could be observed in writhing animals administered acetic-acid intraperitoneally. Moreover, analgesia was totally blocked by the administration of N-nitro-L-arginine, a nitric oxide synthase inhibitor, to accessory olfactory bulbs prior to the exposure. The present results indicate that the olfactory system plays an important role in modulation of radiation-induced analgesia, and a possible involvement of nitric oxide in the formation of recognition memory subjected to repeated X-rays. Relatively higher doses (5 cGy x 9 days, 5 cGy x 12 days), however, did not induce such effects, namely, the decline of nociceptive response was limited to the animals irradiated with the smaller dose. (author)

  4. Corrigendum to "Acute and repeated exposure to social stress reduces gut microbiota diversity in Syrian hamsters" [Behav. Brain Res. 345 (2018) 39-48].

    Science.gov (United States)

    Partrick, Katherine A; Chassaing, Benoit; Beach, Linda Q; McCann, Katharine E; Gewirtz, Andrew T; Huhman, Kim L

    2018-08-01

    Social stress can promote a variety of neuropsychiatric illnesses, many of which have a high co-morbidity with gastrointestinal disorders. Recent data indicate that gastrointestinal microbiota can affect their host's brain and behavior. Syrian hamsters are ideal subjects for social stress research because they are territorial, aggressive, and rapidly form dominant/subordinate relationships. The purpose of this study was to determine if exposure to social stress in hamsters alters gut microbiota in dominants and subordinates after an agonistic encounter and if pre-stress gut microbiota composition is correlated with the outcome of such a conflict. Microbiota composition was assessed via 16S mRNA Illumina sequencing on fecal samples. One agonistic encounter caused a decrease in alpha diversity in both dominant and subordinate animals with a more pronounced decrease after repeated encounters. PERMANOVA analysis of the unweighted unifrac distance revealed a distinct change in beta diversity after one and nine encounters in both dominants and subordinates. Linear discriminant analysis (LEfSE) showed bacteria from the order Lactobacillales were significantly reduced following social stress in both dominants and subordinates, and both groups exhibited increases in phyla Bacteroidetes and decreases in phyla Firmicutes following repeated encounters. LEfSE analysis on samples collected prior to social interaction revealed that some microbial taxa were correlated with a hamster achieving dominant or subordinate status. These data suggest that even an acute exposure to social stress can impact gastrointestinal microbiota and that the state of the microbial community before social stress may predict dominant/subordinate status following a subsequent agonistic encounter. Copyright © 2018.

  5. Twenty-three generations of mice bidirectionally selected for open-field thigmotaxis: selection response and repeated exposure to the open field.

    Science.gov (United States)

    Leppänen, Pia K; Ravaja, N; Ewalds-Kvist, S B M

    2006-03-01

    We examined: (a) the response to bidirectional selection for open-field (OF) thigmotaxis in mice for 23 generations and (b) the effects of repeated exposure (during 5 days) on different OF behaviors in the selectively bred high OF thigmotaxis (HOFT) and low OF thigmotaxis (LOFT) mice. A total of 2049 mice were used in the study. Prior to the testing in the selection experiment, the mice were exposed to the OF apparatus for approximately 2 min on each of 4 consecutive days. Thus, the selection was based on the scores registered on the 5th day after the four habituation periods. The HOFT mice were more thigmotactic than the LOFT mice in almost each generation. The HOFT mice also tended to rear less than the LOFT mice, which was explained by the inverse relationship between emotionality and exploratory tendencies. The lines did not generally differ in ambulation. Sex differences were found in thigmotaxis, ambulation, and rearing. In the repeated exposure experiment, the development of nine different OF behaviors across the 5 days of testing was addressed. Both lines ambulated, explored, and reared most on the 1st, 4th, and 5th days. Grooming and radial latency decreased and thigmotaxis increased linearly across the testing days. Line differences were found in ambulation, exploration, grooming, and rearing, while sex differences were manifested in ambulation and exploration. The line difference in thigmotaxis was evident only on the 5th day. Temporal changes were partially at variance with the general assumptions. OF thigmotaxis was found to be a powerful characteristic for producing two diverging lines of mice.

  6. Controlling criteria for radiation exposure of astronauts and space workers

    International Nuclear Information System (INIS)

    Katoh, Kazuaki

    1989-01-01

    Space workers likely to suffer from radiation exposure in the outer space are currently limited to the U.S. and Soviet Union, and only a small amount of data and information is available concerning the techniques and criteria for control of radiation exposure in this field. Criteria used in the Soviet Union are described first. The criteria (TRS-75), called the Radiation Safety Criteria for Space Navigation, are tentative ones set up in 1975. They are based on risk assessment. The standard radiation levels are established based on unit flight time: 50rem for 1 month, 80rem for 3 months, 110rem for 6 months and 150rem for 12 months. These are largely different from the emergency exposure limit of 100mSv (10rem) specified in a Japanese law, and the standard annual exposure value of 50mSv (5rem) for workers in nuclear power plants at normal times. For the U.S., J.A. Angelo, Jr., presented a paper titled 'Radiation Protection Issues and Techniques concerning Extended Manned Space Missions' at an IAEA meeting held in 1988. Though the criteria shown in the paper are not formal ones at the national level, similar criteria are expected to be adopted by the nation in the near future. The exposure limits recommended in the paper include a depth dose of 1-4Sv for the whole life span of a worker. (Nogami, K.)

  7. Repeated tender point injections of granisetron alleviate chronic myofascial pain--a randomized, controlled, double-blinded trial.

    Science.gov (United States)

    Christidis, Nikolaos; Omrani, Shahin; Fredriksson, Lars; Gjelset, Mattias; Louca, Sofia; Hedenberg-Magnusson, Britt; Ernberg, Malin

    2015-01-01

    Serotonin (5-HT) mediates pain by peripheral 5-HT3-receptors. Results from a few studies indicate that intramuscular injections of 5-HT3-antagonists may reduce musculoskeletal pain. The aim of this study was to investigate if repeated intramuscular tender-point injections of the 5-HT3-antagonist granisetron alleviate pain in patients with myofascial temporomandibular disorders (M-TMD). This prospective, randomized, controlled, double blind, parallel-arm trial (RCT) was carried out during at two centers in Stockholm, Sweden. The randomization was performed by a researcher who did not participate in data collection with an internet-based application ( www.randomization.com ). 40 patients with a diagnose of M-TMD according to the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) were randomized to receive repeated injections, one week apart, with either granisetron (GRA; 3 mg) or isotonic saline as control (CTR). The median weekly pain intensities decreased significantly at all follow-ups (1-, 2-, 6-months) in the GRA-group (Friedman test; P  0.075). The numbers needed to treat (NNT) were 4 at the 1- and 6-month follow-ups, and 3.3 at the 2-month follow-up in favor of granisetron. Repeated intramuscular tender-point injections with granisetron provide a new pharmacological treatment possibility for myofascial pain patients with repeated intramuscular tender-point injections with the serotonin type 3 antagonist granisetron. It showed a clinically relevant pain reducing effect in the temporomandibular region, both in a short- and long-term aspect. European Clinical Trials Database 2005-006042-41 as well as at Clinical Trials NCT02230371 .

  8. Grand Theft Auto IV comes to Singapore: effects of repeated exposure to violent video games on aggression.

    Science.gov (United States)

    Teng, Scott Kie Zin; Chong, Gabriel Yew Mun; Siew, Amy Sok Cheng; Skoric, Marko M

    2011-10-01

    Given the increasingly dominant role of video games in the mainstream entertainment industry, it is no surprise that the scholarly debate about their impact has been lively and well attended. Although >100 studies have been conducted to examine the impact of violent video games on aggression, no clear consensus has been reached, particularly in terms of their long-term impact on violent behavior and aggressive cognitions. This study employs a first-ever longitudinal laboratory-based experiment to examine longer-term effects of playing a violent video game. One hundred thirty-five participants were assigned either to the treatment condition where they played a violent video game in a controlled laboratory setting for a total of 12 hours or to the control group where they did not play a game. Participants in the treatment group played Grand Theft Auto IV over a period of 3 weeks and were compared with a control group on the posttest measures of trait aggression, attitudes toward violence, and empathy. The findings do not support the assertion that playing a violent video game for a period of 3 weeks increases aggression or reduces empathy, but they suggest a small increase in proviolence attitudes. The implications of the findings are discussed.

  9. Facile fabrication of controllable zinc oxide nanorod clusters on polyacrylonitrile nanofibers via repeatedly alternating immersion method

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Ying; Li, Xia; Yu, Hou-Yong, E-mail: phdyu@zstu.edu.cn [Zhejiang Sci-Tech University, The Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Ministry of Education, College of Materials and Textiles (China); Hu, Guo-Liang; Yao, Ju-Ming, E-mail: yaoj@zstu.edu.cn [Zhejiang Sci-Tech University, National Engineering Lab for Textile Fiber Materials and Processing Technology (China)

    2016-12-15

    Polyacrylonitrile/zinc oxide (PAN/ZnO) composite nanofiber membranes with different ZnO morphologies were fabricated by repeatedly alternating hot–cold immersion and single alternating hot–cold immersion methods. The influence of the PAN/ZnCl{sub 2} ratio and different immersion methods on the morphology, microstructure, and properties of the nanofiber membranes was investigated by using field-emission scanning electron microscopy (FE-SEM), Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) analysis, thermogravimetric analysis (TGA), and ultraviolet–visible (UV–Vis) spectroscopy. A possible mechanism for different morphologies of PAN/ZnO nanofiber membranes with different PAN/ZnCl{sub 2} ratio through different immersion processes was presented, and well-dispersed ZnO nanorod clusters with smallest average dimeter of 115 nm and hexagonal wurtzite structure were successfully anchored onto the PAN nanofiber surface for R-7/1 nanofiber membrane. Compared to S-5/1 prepared by single alternating hot–cold immersion method, the PAN/ZnO nanofiber membrane fabricated by repeatedly alternating hot–cold immersion method (especially for R-7/1) showed improved thermal stability and high photocatalytic activity for methylene blue (MB). Compared to S-5/1, decomposition temperature at 5% weight loss (T{sub 5%}) was increased by 43 °C from 282 to 325 °C for R-7/1; meanwhile, R-7/1 showed higher photocatalytic degradation ratio of approximately 100% (after UV light irradiation for 8 h) than 65% for S-5/1 even after irradiation for 14 h. Moreover, the degradation efficiency of R-7/1 with good reuse stability remained above 94% after 3 cycles.

  10. Repeated tongue lift movement induces neuroplasticity in corticomotor control of tongue and jaw muscles in humans.

    Science.gov (United States)

    Komoda, Yoshihiro; Iida, Takashi; Kothari, Mohit; Komiyama, Osamu; Baad-Hansen, Lene; Kawara, Misao; Sessle, Barry; Svensson, Peter

    2015-11-19

    This study investigated the effect of repeated tongue lift training (TLT) on the excitability of the corticomotor representation of the human tongue and jaw musculature. Sixteen participants performed three series of TLT for 41 min on each of 5 consecutive days. Each TLT series consisted of two pressure levels (5 kPa and 10 kPa). All participants underwent transcranial magnetic stimulation (TMS) and electromyographic (EMG) recordings of motor evoked potentials (MEPs) in four sessions: (1) before TLT on Day 1 (baseline), (2) after TLT on Day 1, (3) before TLT on Day 5, and (4) after TLT on Day 5. EMG recordings from the left and right tongue dorsum and masseter muscles were made at three pressure levels (5 kPa, 10 kPa, 100% tongue lift), and tongue, masseter, and first dorsal interosseous (FDI) MEPs were measured. There were no significant day-to-day differences in the tongue pressure during maximum voluntary contractions. The amplitudes and thresholds of tongue and masseter MEPs after TLT on Day 5 were respectively higher and lower than before TLT on Day 1 (P<0.005), and there was also a significant increase in tongue and masseter MEP areas; no significant changes occurred in MEP onset latencies. FDI MEP parameters (amplitude, threshold, area, latency) were not significantly different between the four sessions. Our findings suggest that repeated TLT can trigger neuroplasticity reflected in increased excitability of the corticomotor representation of not only the tongue muscles but also the masseter muscles. Copyright © 2015. Published by Elsevier B.V.

  11. Radiation exposure control during EMCCR campaign at MAPS

    International Nuclear Information System (INIS)

    Jawahar, S.; Singha Roy, S.

    2003-01-01

    Enmasse Coolant Channel Replacement (EMCCR) work is second of its kind for Indian PHWR- next to RAPS - 2 campaign- after successful demonstration of ability by NPCIL to carry out such major core component maintenance. The Challenges posed during such campaign are mainly attributed to the radiation field, continuous occupancy, and large quantity of material handling for execution as well as preparing infrastructure, exposure control for large number of workmen. Extensive planning was carried out to address all these issues in order to reduce the downtime of the station keeping the collective dose as low as reasonable achievable (ALARA). This paper highlights the strategy adopted, logistics involved in execution of work and the efforts taken to control radiation exposure during this major campaign. (author)

  12. Food acceptability in field studies with US army men and women: relationship with food intake and food choice after repeated exposures.

    Science.gov (United States)

    de Graaf, Cees; Kramer, F Matthew; Meiselman, Herbert L; Lesher, Larry L; Baker-Fulco, Carol; Hirsch, Edward S; Warber, John

    2005-02-01

    Laboratory data with single exposures showed that palatability has a positive relationship with food intake. The question addressed in this study is whether this relationship also holds over repeated exposures in non-laboratory contexts in more natural environments. The data were collected in four field studies, lasting 4-11 days with 307 US Army men and 119 Army women, and comprised 5791 main meals and 8831 snacks in total. Acceptability was rated on the nine point hedonic scale, and intake was registered in units of 1/4, 1/2, 3/4, or 1 or more times of the provided portion size. Correlation coefficients between individual acceptability ratings and intakes varied from 0.22 to 0.62 for the main meals (n=193-2267), and between 0.13 and 0.56 for the snacks (n=304-2967). The likelihood of choosing a meal for the second time was positively related to the acceptability rating of the meal when it was consumed for the first time. The results reinforce the importance of liking in food choice and food intake/choice behavior. However, the magnitude of the correlation coefficients between acceptability ratings and food intake suggest that environmental factors also have an important role in determining intake and choice.

  13. External radiation exposure control system in accelerator facilities

    International Nuclear Information System (INIS)

    Ogawa, Tatsuhiko; Iimoto, Takeshi; Kosako, Toshiso

    2011-01-01

    The external exposure control systems in KEK and CERN are discussed to find out good practices and unreasonableness of radiation control in accelerator facilities, which plays an important role in optimizing national and/or site specific radiological regulations, referring to relevant ICRP publications. Personal dose limits and radiation area classifications were analyzed and their reasonableness were explored. Good example of supervised areas, area classification based on realistic assumptions on working time etc are found. On the other hand, unreasonable systems, that are often attributed to the national regulation or ideas presented in the old publications are also found. (author)

  14. Repeated Acute Oral Exposure to Cannabis sativa Impaired Neurocognitive Behaviours and Cortico-hippocampal Architectonics in Wistar Rats.

    Science.gov (United States)

    Imam, A; Ajao, M S; Akinola, O B; Ajibola, M I; Ibrahim, A; Amin, A; Abdulmajeed, W I; Lawal, Z A; Ali-Oluwafuyi, A

    2017-03-06

    The most abused illicit drug in both the developing and the developed world is Cannabis disposing users to varying forms of personality disorders. However, the effects of cannabis on cortico-hippocampal architecture and cognitive behaviours still remain elusive.  The present study investigated the neuro-cognitive implications of oral cannabis use in rats. Eighteen adult Wistar rats were randomly grouped to three. Saline was administered to the control rats, cannabis (20 mg/kg) to the experimental group I, while Scopolamine (1 mg/kg. ip) was administered to the last group as a standard measure for the cannabis induced cognitive impairment. All treatments lasted for seven consecutive days. Open Field Test (OFT) was used to assess locomotor activities, Elevated Plus Maze (EPM) for anxiety-like behaviour, and Y maze paradigm for spatial memory and data subjected to ANOVA and T test respectively. Thereafter, rats were sacrificed and brains removed for histopathological studies. Cannabis significantly reduced rearing frequencies in the OFT and EPM, and increased freezing period in the OFT. It also reduced percentage alternation similar to scopolamine in the Y maze, and these effects were coupled with alterations in the cortico-hippocampal neuronal architectures. These results point to the detrimental impacts of cannabis on cortico-hippocampal neuronal architecture and morphology, and consequently cognitive deficits.

  15. Control of internal exposure doses of Belarus population

    International Nuclear Information System (INIS)

    Minenko, V.; Drozdovich, V.; Ulanovski, A.; Ternov, V.I.; Vasilyeva, I.

    1997-01-01

    Starting from May 1986 instrumental control of internal exposure is being carried out in Belarus using different equipment. In earlier, iodine period, the basic aim of the control was a mass screening of the population for defining of iodine content in thyroid. After the iodine period attention of the radiological control was focused on monitoring of caesium radionuclides content in human bodies of the inhabitants of radioactively contaminated territories. Goals of the control were changing, depending on the time that passed since the day of the accident. Nowadays the National Commission of Belarus recognizes entering of the, Republic into rehabilitation period of the accident of the Chernobyl Nuclear Power Plant. Developed Conception of Protection Measures for the rehabilitation period for the population living at the territories affected by the radioactive contamination in the result of the Chernobyl catastrophe

  16. The Relative Effects of Manual Versus Automatic Exposure Control on Radiation Dose to Vital Organs in Total Hip Arthroplasty.

    Science.gov (United States)

    Harper, Katharine D; Li, Shidong; Jennings, Rachel; Amer, Kamil M; Haydel, Christopher; Ali, Sayed

    2018-01-01

    Technologic advances have reduced medical radiation exposure while maintaining image quality. The purpose of this study was to determine the effects of the presence of total hip arthroplasty implants, compared with native hips, on radiation exposure of the most radiosensitive organs when manual and automatic exposure control settings are used. Detection probes were placed at six locations (stomach, sigmoid colon, right pelvic wall, left pelvic wall, pubic symphysis, and anterior pubic skin) in a cadaver. Radiographs were obtained with the use of manual and automatic exposure control protocols, with exposures recorded. A total hip arthroplasty implant was placed in the cadaver, probe positioning was confirmed, and the radiographs were repeated, with exposure values recorded. The control probe placed at the stomach had values ranging from 0.00 mSv to 0.01 mSv in protocols with and without implants. With the manual protocol, exposures in the pelvis ranged from 0.36 mSv to 2.74 mSv in the native hip and from 0.33 mSv to 2.24 mSv after implant placement. The increases in exposure after implant placement, represented as relative risk, were as follows: stomach, 1.000; pubic symphysis, 0.818; left pelvic wall, 1.381; sigmoid colon, 1.550; right pelvic wall, 0.917; and anterior pubic skin, 1.015. With automatic exposure control, exposures in the pelvis ranged from 0.07 mSv to 0.89 mSv in the native hip and from 0.21 mSv to 1.15 mSv after implant placement. With automatic exposure control, the increases in exposure after implant placement, represented as relative risk, were as follows: stomach, 1.000; pubic symphysis, 1.292; left pelvic wall, 1.476; sigmoid colon, 2.182; right pelvic wall, 3.000; and anterior pubic skin, 1.378. The amount of radiation to which patients are exposed as a result of medical procedures or imaging, and whether exposure is associated with an increased risk of malignant transformation, are the subject of ongoing debate. We found that after insertion

  17. Perinatal taurine exposure affects adult arterial pressure control

    Science.gov (United States)

    Roysommuti, Sanya; Wyss, J. Michael

    2012-01-01

    Taurine is an abundant free amino acid found in mammalian cells that contributes to many physiologic functions from that of a simple cell osmolyte to a programmer of adult health and disease. Taurine’s contribution extends from conception throughout life, but its most critical exposure period is during perinatal life. In adults, taurine supplementation prevents or alleviates cardiovascular disease and related complications. In contrast, low taurine consumption coincides with increased risk of cardiovascular disease, obesity and type II diabetes. This review focuses on the effects that altered perinatal taurine exposure has on long-term mechanisms that control adult arterial blood pressure and could thereby contribute to arterial hypertension through its ability to program these cardiovascular regulatory mechanisms very early in life. The modifications of these mechanisms can last a lifetime and transfer to the next generation, suggesting that epigenetic mechanisms underlie the changes. The ability of perinatal taurine exposure to influence arterial pressure control mechanisms and hypertension in adult life appears to involve the regulation of growth and development, the central and autonomic nervous system, the renin-angiotensin system, glucose-insulin interaction and changes to heart, blood vessels and kidney function. PMID:23070226

  18. Negative control exposure studies in the presence of measurement error: implications for attempted effect estimate calibration.

    Science.gov (United States)

    Sanderson, Eleanor; Macdonald-Wallis, Corrie; Davey Smith, George

    2018-04-01

    Negative control exposure studies are increasingly being used in epidemiological studies to strengthen causal inference regarding an exposure-outcome association when unobserved confounding is thought to be present. Negative control exposure studies contrast the magnitude of association of the negative control, which has no causal effect on the outcome but is associated with the unmeasured confounders in the same way as the exposure, with the magnitude of the association of the exposure with the outcome. A markedly larger effect of the exposure on the outcome than the negative control on the outcome strengthens inference that the exposure has a causal effect on the outcome. We investigate the effect of measurement error in the exposure and negative control variables on the results obtained from a negative control exposure study. We do this in models with continuous and binary exposure and negative control variables using analysis of the bias of the estimated coefficients and Monte Carlo simulations. Our results show that measurement error in either the exposure or negative control variables can bias the estimated results from the negative control exposure study. Measurement error is common in the variables used in epidemiological studies; these results show that negative control exposure studies cannot be used to precisely determine the size of the effect of the exposure variable, or adequately adjust for unobserved confounding; however, they can be used as part of a body of evidence to aid inference as to whether a causal effect of the exposure on the outcome is present.

  19. [Advances in research on automatic exposure control of mammography system].

    Science.gov (United States)

    Wang, Guoyi; Ye, Chengfu; Wu, Haiming; Wang, Tainfu; Zhang, Hong

    2014-12-01

    Mammography imaging is one of the most demanding imaging modalities from the point of view of the bal- ance between image quality (the visibility of small size and/or low contrast structures) and dose (screening of many asymptomatic people). Therefore, since the introduction of the first dedicated mammographic units, many efforts have been directed to seek the best possible image quality while minimizing patient dose. The performance of auto- matic exposure control (AEC) is the manifestation of this demand. The theory of AEC includes exposure detection and optimization and also involves some accomplished methodology. This review presents the development and present situa- tion of spectrum optimization, detector evolution, and the way how to accomplish and evaluate AEC methods.

  20. A step-by-step introduction to vegetables at the beginning of complementary feeding. The effects of early and repeated exposure.

    Science.gov (United States)

    Hetherington, Marion M; Schwartz, C; Madrelle, J; Croden, F; Nekitsing, C; Vereijken, C M J L; Weenen, H

    2015-01-01

    Breastfeeding (BF) is associated with willingness to accept vegetables. This may be due to the variety of flavours delivered via breast milk. Some mothers add vegetables to milk during complementary feeding (CF) to enhance acceptance. The present study tested a step-by-step exposure to vegetables in milk then rice during CF, on intake and liking of vegetables. Just before CF, enrolled mothers were randomised to an intervention (IG, n = 18; 6 BF) or control group (CG, n = 18; 6 BF). IG infants received 12 daily exposures to vegetable puree added to milk (days 1-12), then 12 × 2 daily exposures to vegetable puree added to rice at home (days 13-24). Plain milk and rice were given to CG. Then both received 11 daily exposures to vegetable puree. Intake was weighed and liking rated on days 25-26 and 33-35 after the start of CF in the laboratory, supplemented by the same data recorded at home. Vegetables were rotated daily (carrots, green beans, spinach, broccoli). Intake, liking and pace of eating were greater for IG than CG infants. Intake and liking of carrots were greater than green beans. However, at 6m then 18m follow up, vegetable (carrot > green beans) but not group differences were observed. Mothers reported appreciation of the structure and guidance of this systematic approach. Early exposure to vegetables in a step-by-step method could be included in CF guidelines and longer term benefits assessed by extending the exposure period. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

  1. The Effects of a Single Whole-Body Cryotherapy Exposure on Physiological, Performance, and Perceptual Responses of Professional Academy Soccer Players After Repeated Sprint Exercise.

    Science.gov (United States)

    Russell, Mark; Birch, Jack; Love, Thomas; Cook, Christian J; Bracken, Richard M; Taylor, Tom; Swift, Eamon; Cockburn, Emma; Finn, Charlie; Cunningham, Daniel; Wilson, Laura; Kilduff, Liam P

    2017-02-01

    Russell, M, Birch, J, Love, T, Cook, CJ, Bracken, RM, Taylor, T, Swift, E, Cockburn, E, Finn, C, Cunningham, D, Wilson, L, and Kilduff, LP. The effects of a single whole-body cryotherapy exposure on physiological, performance, and perceptual responses of professional academy soccer players after repeated sprint exercise. J Strength Cond Res 31(2): 415-421, 2017-In professional youth soccer players, the physiological, performance, and perceptual effects of a single whole-body cryotherapy (WBC) session performed shortly after repeated sprint exercise were investigated. In a randomized, counterbalanced, and crossover design, 14 habituated English Premier League academy soccer players performed 15 × 30 m sprints (each followed by a 10 m forced deceleration) on 2 occasions. Within 20 minutes of exercise cessation, players entered a WBC chamber (Cryo: 30 seconds at -60° C, 120 seconds at -135° C) or remained seated (Con) indoors in temperate conditions (∼25° C). Blood and saliva samples, peak power output (countermovement jump), and perceptual indices of recovery and soreness were assessed pre-exercise and immediately, 2-hour and 24-hour postexercise. When compared with Con, a greater testosterone response was observed at 2-hour (+32.5 ± 32.3 pg·ml, +21%) and 24-hour (+50.4 ± 48.9 pg·ml, +28%) postexercise (both P = 0.002) in Cryo (trial × treatment interaction: P = 0.001). No between-trial differences were observed for other salivary (cortisol and testosterone/cortisol ratio), blood (lactate and creatine kinase), performance (peak power output), or perceptual (recovery or soreness) markers (all trial × treatment interactions: P > 0.05); all of which were influenced by exercise (time effects: all P ≤ 0.05). A single session of WBC performed within 20 minutes of repeated sprint exercise elevated testosterone concentrations for 24 hours but did not affect any other performance, physiological, or perceptual measurements taken. Although unclear, WBC may be

  2. Repeated Gestational Exposure of Mice to Chlorpyrifos Oxon Is Associated with Paraoxonase 1 (PON1) Modulated Effects in Maternal and Fetal Tissues

    Science.gov (United States)

    Co, Aila L.; Hay, Ariel M.; MacDonald, James W.; Bammler, Theo K.; Farin, Federico M.; Costa, Lucio G.; Furlong, Clement E.

    2014-01-01

    Chlorpyrifos oxon (CPO), the toxic metabolite of the organophosphorus (OP) insecticide chlorpyrifos, causes developmental neurotoxicity in humans and rodents. CPO is hydrolyzed by paraoxonase-1 (PON1), with protection determined by PON1 levels and the human Q192R polymorphism. To examine how the Q192R polymorphism influences fetal toxicity associated with gestational CPO exposure, we measured enzyme inhibition and fetal-brain gene expression in wild-type (PON1+/+), PON1-knockout (PON1−/−), and tgHuPON1R192 and tgHuPON1Q192 transgenic mice. Pregnant mice exposed dermally to 0, 0.50, 0.75, or 0.85 mg/kg/d CPO from gestational day (GD) 6 through 17 were sacrificed on GD18. Biomarkers of CPO exposure inhibited in maternal tissues included brain acetylcholinesterase (AChE), red blood cell acylpeptide hydrolase (APH), and plasma butyrylcholinesterase (BChE) and carboxylesterase (CES). Fetal plasma BChE was inhibited in PON1−/− and tgHuPON1Q192, but not PON1+/+ or tgHuPON1R192 mice. Fetal brain AChE and plasma CES were inhibited in PON1−/− mice, but not in other genotypes. Weighted gene co-expression network analysis identified five gene modules based on clustering of the correlations among their fetal-brain expression values, allowing for correlation of module membership with the phenotypic data on enzyme inhibition. One module that correlated highly with maternal brain AChE activity had a large representation of homeobox genes. Gene set enrichment analysis revealed multiple gene sets affected by gestational CPO exposure in tgHuPON1Q192 but not tgHuPON1R192 mice, including gene sets involved in protein export, lipid metabolism, and neurotransmission. These data indicate that maternal PON1 status modulates the effects of repeated gestational CPO exposure on fetal-brain gene expression and on inhibition of both maternal and fetal biomarker enzymes. PMID:25070982

  3. Is it necessary to repeat quality control procedures for head and neck patients?

    International Nuclear Information System (INIS)

    Mitine, C.; Leunens, G.; Verstraete, J.; Blanckaert, N.; Van Dam, J.; Dutreix, A.; Van der Schueren, E.

    1991-01-01

    Using serial verification films for detection of localization errors and in vivo measurements of the delivered dose, a comparison was made of information obtained from a single check on the 1st treatment session or from repeated checks in subsequent irradiations, leading to an assess-ment of the predictive value of a single check. A total number of 215 films and 261 entrance dose measurements have been performed on 34 fields for 10 head and neck patients. The patients are immobilized with individual plastic masks fixed on the couch and treated on a 6 MV linac, supplied with an automatic verification system excluding the couch para-meters. The global results show Gaussian frequency distributions with standard deviations of 4 mm for port film measurements and 3.4 percent for the dose measurements. Late errors (>5 mm displacement and >4 per-cent deviation from the expected dose) have been detected in 16 percent in the cranio-caudal direction and 24 percent in the antero-posterior direction with port films and in 15 percent of the in vivo measurements. In order to identify the nature of errors, which can be random or syste-matic, the 1st measurement is taken as the reference value and shows that the consecutive measurements on the same field were reproducible with standard deviations of respectively 2.5 mm and 1.8 percent. This means that a large part of the spread of the global results can be ex-plained by systematic errors in the treatment preparation chain. With the 1st check, 6 out of 10 systematic localization errors and 7 out of 7 systematic errors leading to erroneous dose delivery have been detected. Therefore, most of the systematic errors, which affect the overall quality of the treatment, can be identified with the 1st check. The 4 systematic localization errors, missed with the 1st film, were of rather limited size: only 1 of them showed a mean displacement larger than 7 mm. Because the 1st measurement is an acceptable indication of the over-all quality of

  4. [Evaluation of postural control systems in elderly patients with repeated falls].

    Science.gov (United States)

    González Ramírez, Alfonso; Lázaro del Nogal, Montserrat; Ribera Casado, José Manuel

    2008-01-01

    a) to describe postural control disorders in elderly patients with recurrent falls; b) to analyze the influence of sensory deficits on centre of gravity control mechanisms; and c) to assess the functional consequences of balance disorders and falls in this group of patients. patients aged more than 65 years old referred to a falls unit with two or more falls in the previous 6 months were included in this study. The protocol included posturographic studies with a Neurocom Balance Master. To evaluate motor control, Rhythmic Weight Shift (RWS test) was performed. To assess sensorial control, Modified Clinical Test of Sensory Interaction on Balance (MCT test) was used. Other tests performed were the Sit to Stand (SS test), Walk across (WA test) and Step up over (SO test). a total of 109 patients (85.3% women) were studied. Mean age was 78.01 years (SD: 5.38). Disorders in one or more afferent sensorial systems were found in 51.7% of the patients (27.5% visual deficiencies, 17.6% vestibular alterations, and 6.6% somatosensorial deficits). Two afferent systems were compromised in 25.3%, and all three were compromised in 11.1% of the patients. No significant differences were found in directional control (RWS) when compared with the number of altered systems. posturographic studies provide sensitive information on static and dynamic centre of gravity control systems, eventual sensory deficits, and patients' ability to carry out basic activities of daily living. In our sample, the most frequent deficit was visual impairment. This information is essential to establish a correct management programme.

  5. Quality control for exposure assessment in epidemiological studies

    DEFF Research Database (Denmark)

    Bornkessel, C; Blettner, M; Breckenkamp, J

    2010-01-01

    In the framework of an epidemiological study, dosemeters were used for the assessment of radio frequency electromagnetic field exposure. To check the correct dosemeter's performance in terms of consistency of recorded field values over the entire study period, a quality control strategy...... was developed. In this paper, the concept of quality control and its results is described. From the 20 dosemeters used, 19 were very stable and reproducible, with deviations of a maximum of +/-1 dB compared with their initial state. One device was found to be faulty and its measurement data had to be excluded...... from the analysis. As a result of continuous quality control procedures, the confidence in the measurements obtained during the field work was strengthened significantly....

  6. Repeated exposure to antibiotics in infancy: a predisposing factor for juvenile idiopathic arthritis or a sign of this group's greater susceptibility to infections?

    Science.gov (United States)

    Arvonen, Miika; Virta, Lauri J; Pokka, Tytti; Kröger, Liisa; Vähäsalo, Paula

    2015-03-01

    Previous exposure to antibiotics has been associated with the pathogenesis of several autoimmune diseases. Our objective was to explore whether childhood exposure to antibiotics would be associated with the risk of developing juvenile idiopathic arthritis (JIA). The material was collected from national registers containing all children born in 2000-2010 in Finland and diagnosed with JIA by the end of December 2012 (n = 1298) and appropriate controls (n = 5179) matched for age, sex, and place of birth. All purchases of antibiotics were collected from birth until the index date (i.e., the date of special reimbursement for JIA medications). A conditional logistic regression was performed to evaluate the association between the exposure to antibiotics and the risk of JIA. The risk of JIA increased with the number of antibiotic purchases from birth to the index date: for ≥ 1 purchases versus none, OR 1.6, 95% CI 1.3-1.9 with an upward trend in OR (p Antibiotic groups lincosamides and cephalosporins showed the strongest association with JIA (OR 6.6, 95% CI 3.7-11.7, and OR 1.6, 95% CI 1.4-1.8, respectively). Overall exposure to antibiotics before 2 years of age was associated with an increased risk of JIA (OR 1.4, 95% CI 1.2-1.6), with the trend test of OR (p antibiotics may predispose individuals to develop JIA. Alternatively, the apparent association may reflect shared susceptibility to infections and JIA.

  7. Retrospective exposure assessment and quality control in an international multi-centre case-control study

    DEFF Research Database (Denmark)

    Tinnerberg, H; Heikkilä, P; Huici-Montagud, A

    2003-01-01

    The paper presents the exposure assessment method and quality control procedure used in an international, multi-centre case-control study within a joint Nordic and Italian cohort. This study was conducted to evaluate whether occupational exposure to carcinogens influenced the predictivity of high...... was higher among the original assessors (the assessor from the same country as the subject) than the average prevalence assessed by the other four in the quality control round. The original assessors classified more job situations as exposed than the others. Several reasons for this are plausible: real...... country-specific differences, differences in information available to the home assessor and the others and misunderstandings or difficulties in translation of information. To ensure the consistency of exposure assessments in international retrospective case-control studies it is important to have a well...

  8. Control of occupational exposure to cosmic radiation outside the atmosphere

    International Nuclear Information System (INIS)

    Katoh, Kazuaki; Kaneko, Masahito

    2000-01-01

    Japan is participating in the project of constructing ISS, International Space Station, and taking part of constructing JEM, Japan Experimental Module. It is expected that people working in this module upon completion should be controlled their exposure to cosmic radiation according to Japanese laws. Hence, the issue has been studied by a committee in NASDA, National Space Development Agency of Japan. In 1999, its interim report was released and public comments had been invited. In this presentation, following the introduction of the gist of the interim report as well as comments by the authors, countermeasures are proposed. (author)

  9. Exposure to tobacco marketing and support for tobacco control policies.

    Science.gov (United States)

    Hammond, David; Costello, Mary-Jean; Fong, Geoffrey T; Topham, Jennifer

    2006-01-01

    To examine the salience of tobacco marketing on postsecondary campuses and student support for tobacco control policies. Face-to-face surveys were conducted with 1690 students at 3 universities in southwestern Ontario. Virtually all (97%) students reported noticing tobacco marketing in the past year, and 35% reported noticing marketing on campus. There was strong support for smoke-free restrictions on campus, including restaurants and bars (82%), and for prohibitions on campus marketing. The presence of campus policies was associated with reduced exposure to marketing and increased policy support. There is strong support among students to remove tobacco marketing from campus and to introduce comprehensive smoke-free restrictions.

  10. Optimization of radiation protection for the control of occupational exposure

    International Nuclear Information System (INIS)

    Esseyin, S.S.

    2012-04-01

    This project work provides practical information on how to apply the optimization of protection in the workplace. The principle of optimization states that, all reasonable efforts be made to reduce doses, social and economic factors being taken into account. The main objectives of this project work is to limit the risk to health arising from exposure to ionizing radiation in the workplace and to optimize radiation protection was achieved by setting common essential requirements for the control of exposure to radiation, including the specification of employer and employee duties. The acronym ALARA has been used in this project work as it brings to mind the twin concepts of dose reduction and reasonableness. The other main component of this project work is a general review of the means that are likely to be available in most workplaces to reduce exposure. These are divided into global means, which can be applied throughout an organization and those that are more jobs specific. Some of these global means are no more than would be expected in any well managed organization, such as an application of effective and efficient procedures for the management of work and provision for the education and training of workers. (author)

  11. Changes in the α4β2* nicotinic acetylcholine system during chronic controlled alcohol exposure in nonhuman primates.

    Science.gov (United States)

    Hillmer, Ansel T; Tudorascu, Dana L; Wooten, Dustin W; Lao, Patrick J; Barnhart, Todd E; Ahlers, Elizabeth O; Resch, Leslie M; Larson, Julie A; Converse, Alexander K; Moore, Colleen F; Schneider, Mary L; Christian, Bradley T

    2014-05-01

    The precise nature of modifications to the nicotinic acetylcholine receptor (nAChR) system in response to chronic ethanol exposure is poorly understood. The present work used PET imaging to assay α4β2* nAChR binding levels of eight rhesus monkeys before and during controlled chronic ethanol intake. [(18)F]Nifene PET scans were conducted prior to alcohol exposure, and then again after at least 8 months controlled ethanol exposure, including 6 months at 1.5 g/kg/day following a dose escalation period. Receptor binding levels were quantified with binding potentials (BPND) using the cerebellum as a reference region. Alcohol self-administration was assessed as average daily alcohol intake during a 2 month free drinking period immediately following controlled alcohol. Significant decreases in α4β2* nAChR binding were observed in both frontal and insular cortex in response to chronic ethanol exposure. During chronic alcohol exposure, BPND in the lateral geniculate region correlated positively with the amount of alcohol consumed during free drinking. The observed decreases in nAChR availability following chronic alcohol consumption suggest alterations to this receptor system in response to repeated alcohol administration, making this an important target for further study in alcohol abuse and alcohol and nicotine codependence. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  12. Comparative analysis of transcriptomic responses to repeated-dose exposure to 2-MCPD and 3-MCPD in rat kidney, liver and testis.

    Science.gov (United States)

    Buhrke, Thorsten; Schultrich, Katharina; Braeuning, Albert; Lampen, Alfonso

    2017-08-01

    3-Chloro-1,2-propanediol (3-MCPD) and its isomer 2-chloro-1,3-propanediol (2-MCPD) are heat-induced food contaminants present in oil- and fat-containing foodstuff. Kidney and testes are among the main target organs of 3-MCPD. Almost no data on 2-MCPD toxicity are available. Here, transcriptomic responses following repeated-dose exposure of rats to non-toxic doses of 10 mg/kg body weight per day 2-MCPD or 3-MCPD for 28 days were characterized by microarray analysis of kidney, liver, and testes. 3-MCPD exerted more pronounced effects than 2-MCPD in all organs. The limited overlap between the datasets indicates that 2-MCPD and 3-MCPD do not share the same molecular mechanisms of toxicity. By combining transcriptomic data with datasets on proteomic regulation by 3-MCPD, a comprehensive view on 3-MCPD-induced regulation of glucose utilization and oxidative stress response was developed. Bioinformatic analyses revealed that Nrf2 (nuclear factor (erythroid-derived 2)-like 2) signaling is likely to be involved in mediating the oxidative stress response to 3-MCPD. In summary, this study for the first time presents data on alterations in global gene expression by two important food contaminants, 2-MCPD and 3-MCPD. Data demonstrate profound differences between the effects of the two compounds and substantially broaden our knowledge on molecular details of 3-MCPD-induced disturbance of glucose utilization and redox balance. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. The Queensland study of Melanoma: Environmental and Genetic Associations (Q-MEGA). Study design, baseline characteristics, and repeatability of phenotype and sun exposure measures

    Science.gov (United States)

    Baxter, Amanda J.; Hughes, Maria Celia; Kvaskoff, Marina; Siskind, Victor; Shekar, Sri; Aitken, Joanne F.; Green, Adele C.; Duffy, David L.; Hayward, Nicholas K.; Martin, Nicholas G.; Whiteman, David C.

    2013-01-01

    Cutaneous malignant melanoma (CMM) is a major health issue in Queensland, Australia which has the world’s highest incidence. Recent molecular and epidemiologic studies suggest that CMM arises through multiple etiological pathways involving gene-environment interactions. Understanding the potential mechanisms leading to CMM requires larger studies than those previously conducted. This article describes the design and baseline characteristics of Q-MEGA, the Queensland study of Melanoma: Environmental and Genetic Associations, which followed-up four population-based samples of CMM patients in Queensland, including children, adolescents, men aged over 50, and a large sample of adult cases and their families, including twins. Q-MEGA aims to investigate the roles of genetic and environmental factors, and their interaction, in the etiology of melanoma. 3,471 participants took part in the follow-up study and were administered a computer-assisted telephone interview in 2002–2005. Updated data on environmental and phenotypic risk factors, and 2,777 blood samples were collected from interviewed participants as well as a subset of relatives. This study provides a large and well-described population-based sample of CMM cases with follow-up data. Characteristics of the cases and repeatability of sun exposure and phenotype measures between the baseline and the follow-up surveys, from six to 17 years later, are also described. PMID:18361720

  14. Repeated exposure to enhanced UV-B radiation in successive generations increases developmental instability (leaf fluctuating asymmetry) in a desert annual

    International Nuclear Information System (INIS)

    Midgley, G.F.; Wand, S.J.E.; Musil, C.F.

    1998-01-01

    Populations of the desert annual Dimorphotheca sinuata, derived from a common seed stock, were exposed concurrently over four successive generations to either ambient (representing no stratospheric ozone depletion) or elevated (representing 20% stratospheric ozone depletion) UV-B levels during their complete life cycle. Leaf fluctuating asymmetry (FA) was measured in populations of plants grown from seeds of selected generations which had experienced different UV-B exposure histories, and from seeds collected from a wild population of this species which grows in a naturally enhanced UV-B environment. These measured plants had been grown in a greenhouse under essentially UV-B-free conditions. Leaf FA was significantly increased by greater numbers of enhanced UV-B exposures in the parentage of the seed. There was a linear to exponential dose–response relationship between number of UV-B exposure iterations in seed parentage and leaf FA, suggesting that damage to DNA caused by UV-B exposure during plant development may not be fully repaired, and thus be inherited by offspring and accumulated over successive generations in this species. Leaf FA of plants grown from seed from the wild population was not significantly greater than that of control plants whose parentage experienced only ambient UV-B exposures, although this negative result may have been due to low sampling intensity and measurement resolution, and the relatively low UV-B enhancement experienced by the wild population. We conclude that leaf FA may constitute a relatively sensitive yet inexpensive means of quantifying UV-B damage to plants. (author)

  15. 30 CFR 57.5005 - Control of exposure to airborne contaminants.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Control of exposure to airborne contaminants... Underground § 57.5005 Control of exposure to airborne contaminants. Control of employee exposure to harmful airborne contaminants shall be, insofar as feasible, by prevention of contamination, removal by exhaust...

  16. 30 CFR 56.5005 - Control of exposure to airborne contaminants.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Control of exposure to airborne contaminants... Air Quality and Physical Agents Air Quality § 56.5005 Control of exposure to airborne contaminants. Control of employee exposure to harmful airborne contaminants shall be, insofar as feasible, by prevention...

  17. Strategies for Controlling Item Exposure in Computerized Adaptive Testing with the Generalized Partial Credit Model

    Science.gov (United States)

    Davis, Laurie Laughlin

    2004-01-01

    Choosing a strategy for controlling item exposure has become an integral part of test development for computerized adaptive testing (CAT). This study investigated the performance of six procedures for controlling item exposure in a series of simulated CATs under the generalized partial credit model. In addition to a no-exposure control baseline…

  18. Identification of Sources of Endotoxin Exposure as Input for Effective Exposure Control Strategies.

    Science.gov (United States)

    van Duuren-Stuurman, Birgit; Gröllers-Mulderij, Mariska; van de Runstraat, Annemieke; Duisterwinkel, Anton; Terwoert, Jeroen; Spaan, Suzanne

    2018-02-13

    Aim of the present study is to investigate the levels of endotoxins on product samples from potatoes, onions, and seeds, representing a relevant part of the agro-food industry in the Netherlands, to gather valuable insights in possibilities for exposure control measures early in the process of industrial processing of these products. Endotoxin levels on 330 products samples from companies representing the potato, onion, and seed (processing) industry (four potato-packaging companies, five potato-processing companies, five onion-packaging companies, and four seed-processing companies) were assessed using the Limulus Amboecyte Lysate (LAL) assay. As variation in growth conditions (type of soil, growth type) and product characteristics (surface roughness, dustiness, size, species) are assumed to influence the level of endotoxin on products, different types, and growth conditions were considered when collecting the samples. Additionally, waste material, rotten products, felt material (used for drying), and process water were collected. A large variation in the endotoxin levels was found on samples of potatoes, onions, and seeds (overall geometric standard deviation 17), in the range between 0.7 EU g-1 to 16400000 EU g-1. The highest geometric mean endotoxin levels were found in plant material (319600 EU g-1), followed by soil material (49100 EU g-1) and the outer side of products (9300 EU g-1), indicating that removal of plant and soil material early in the process would be an effective exposure control strategy. The high levels of endotoxins found in the limited number of samples from rotten onions indicate that these rotten onions should also be removed early in the process. Mean endotoxin levels found in waste material (only available for seed processing) is similar to the level found in soil material, although the range is much larger. On uncleaned seeds, higher endotoxin levels were found than on cleaned seeds, indicating that cleaning processes are important

  19. The National Environmental Respiratory Center (NERC) experiment in multi-pollutant air quality health research: IV. Vascular effects of repeated inhalation exposure to a mixture of five inorganic gases.

    Science.gov (United States)

    Mauderly, J L; Kracko, D; Brower, J; Doyle-Eisele, M; McDonald, J D; Lund, A K; Seilkop, S K

    2014-09-01

    An experiment was conducted to test the hypothesis that a mixture of five inorganic gases could reproduce certain central vascular effects of repeated inhalation exposure of apolipoprotein E-deficient mice to diesel or gasoline engine exhaust. The hypothesis resulted from preceding multiple additive regression tree (MART) analysis of a composition-concentration-response database of mice exposed by inhalation to the exhausts and other complex mixtures. The five gases were the predictors most important to MART models best fitting the vascular responses. Mice on high-fat diet were exposed 6 h/d, 7 d/week for 50 d to clean air or a mixture containing 30.6 ppm CO, 20.5 ppm NO, 1.4 ppm NO₂, 0.5 ppm SO₂, and 2.0 ppm NH₃ in air. The gas concentrations were below the maxima in the preceding studies but in the range of those in exhaust exposure levels that caused significant effects. Five indicators of stress and pro-atherosclerotic responses were measured in aortic tissue. The exposure increased all five response indicators, with the magnitude of effect and statistical significance varying among the indicators and depending on inclusion or exclusion of an apparent outlying control. With the outlier excluded, three responses approximated predicted values and two fell below predictions. The results generally supported evidence that the five gases drove the effects of exhaust, and thus supported the potential of the MART approach for identifying putative causal components of complex mixtures.

  20. Deployment Repeatability

    Science.gov (United States)

    2016-04-01

    evaluating the deployment repeatability builds upon the testing or analysis of deployment kinematics (Chapter 6) and adds repetition. Introduction...material yield or failure during a test. For the purposes of this chapter, zero shift will refer to permanent changes in the structure, while reversible ...the content of other chapters in this book: Gravity Compensation (Chapter 4) and Deployment Kinematics and Dynamics (Chapter 6). Repeating the

  1. Comparing a single case to a control group - Applying linear mixed effects models to repeated measures data.

    Science.gov (United States)

    Huber, Stefan; Klein, Elise; Moeller, Korbinian; Willmes, Klaus

    2015-10-01

    In neuropsychological research, single-cases are often compared with a small control sample. Crawford and colleagues developed inferential methods (i.e., the modified t-test) for such a research design. In the present article, we suggest an extension of the methods of Crawford and colleagues employing linear mixed models (LMM). We first show that a t-test for the significance of a dummy coded predictor variable in a linear regression is equivalent to the modified t-test of Crawford and colleagues. As an extension to this idea, we then generalized the modified t-test to repeated measures data by using LMMs to compare the performance difference in two conditions observed in a single participant to that of a small control group. The performance of LMMs regarding Type I error rates and statistical power were tested based on Monte-Carlo simulations. We found that starting with about 15-20 participants in the control sample Type I error rates were close to the nominal Type I error rate using the Satterthwaite approximation for the degrees of freedom. Moreover, statistical power was acceptable. Therefore, we conclude that LMMs can be applied successfully to statistically evaluate performance differences between a single-case and a control sample. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. A novel application of capnography during controlled human exposure to air pollution

    Directory of Open Access Journals (Sweden)

    Fila Michael

    2006-10-01

    Full Text Available Abstract Background The objective was to determine the repeatability and stability of capnography interfaced with human exposure facility. Methods Capnographic wave signals were obtained from five healthy volunteers exposed to particle-free, filtered air during two consecutive 5 min intervals, 10 min apart, within the open and then the sealed and operational human exposure facility (HEF. Using a customized setup comprised of the Oridion Microcap® portable capnograph, DA converter and AD card, the signal was acquired and saved as an ASCII file for subsequent processing. The minute ventilation (VE, respiratory rate (RR and expiratory tidal volume (VTE were recorded before and after capnographic recording and then averaged. Each capnographic tracing was analyzed for acceptable waves. From each recorded interval, 8 to 19 acceptable waves were selected and measured. The following wave parameters were obtained: total length and length of phase II and III, slope of phase II and III, area under the curve and area under phase III. In addition, we recorded signal measures including the mean, standard deviation, mode, minimum, maximum – which equals end-tidal CO2 (EtCO2, zero-corrected maximum and true RMS. Results Statistical analysis using a paired t-test for means showed no statistically significant changes of any wave parameters and wave signal measures, corrected for RR and VTE, comparing the measures when the HEF was open vs. sealed and operational. The coefficients of variation of the zero-corrected and uncorrected EtCO2, phase II absolute difference, signal mean, standard deviation and RMS were less than 10% despite a sub-atmospheric barometric pressure, and slightly higher temperature and relative humidity within the HEF when operational. Conclusion We showed that a customized setup for the acquisition and processing of the capnographic wave signal, interfaced with HEF was stable and repeatable. Thus, we expect that analysis of capnographic

  3. Stress responses in juvenile pacu (Piaractus mesopotamicus submitted to repeated air exposure = Respostas de estresse em juvenis de pacu (Piaractus mesopotamicus submetidos à exposição aérea repetitiva

    Directory of Open Access Journals (Sweden)

    Jaqueline Dalbello Biller

    2008-01-01

    Full Text Available Pacu juveniles (5.2 ± 1.5 g were submitted to two one-minute air exposures in a 24h interval, and sampled before the exposure (control and 5, 15, 30 and 60 min., 24 and 48h afterwards for whole-body cortisol, sodium, potassium and calcium ion concentrations. For the first air exposure, there was a trend of increased cortisol concentration after 15 min., whereas in the second air exposure, the cortisol concentration increased significantly within 5 min. after stress was induced. Sodium ion concentrationincreased significantly 24h after both air exposures. Potassium concentration presented fluctuations over the experimental period. Calcium ion concentration increased progressively from 5 to 30 min., in both air exposures. The repeated air exposures exacerbated the cortisol response, but they did not affect the recovery ability of pacu over the experimental period. Additionally, the whole-body cortisol measurement might be a reliable indicator of stress, when sampled fish are smaller and blood volumes are very low, making samples inadequate for analysis.Juvenis de pacu (5,2 ± 1,5 g foram submetidos a duas exposições aéreas de um minuto, em intervalo de 24 horas, e amostradosantes da exposição (controle e 5, 15, 30 e 60 min., 24 e 48 horas depois para análise da concentração corporal de cortisol e dos íons sódio, potássio e cálcio. Na primeira exposição, os peixes apresentaram concentrações de cortisol aumentadas a partir de 15 min., embora não diferissem estatisticamente do controle. Na segunda exposição, a concentração de cortisol aumentou significativamente aos 5 min., retornando às concentrações equivalentes às dos peixes-controle em 30 min.. A concentração do íon sódio aumentousignificativamente 24 horas depois das duas exposições aéreas. A concentração do íon potássio apresentou flutuações durante o experimento, enquanto a do cálcio apresentou-se reduzida aos 5 min, aumentando gradativamente até os 30

  4. Pesticide exposure and risk of Parkinson's disease: A family-based case-control study

    Directory of Open Access Journals (Sweden)

    Scott Burton L

    2008-03-01

    Full Text Available Abstract Background Pesticides and correlated lifestyle factors (e.g., exposure to well-water and farming are repeatedly reported risk factors for Parkinson's disease (PD, but few family-based studies have examined these relationships. Methods Using 319 cases and 296 relative and other controls, associations of direct pesticide application, well-water consumption, and farming residences/occupations with PD were examined using generalized estimating equations while controlling for age-at-examination, sex, cigarette smoking, and caffeine consumption. Results Overall, individuals with PD were significantly more likely to report direct pesticide application than their unaffected relatives (odds ratio = 1.61; 95% confidence interval, 1.13–2.29. Frequency, duration, and cumulative exposure were also significantly associated with PD in a dose-response pattern (p ≤ 0.013. Associations of direct pesticide application did not vary by sex but were modified by family history of PD, as significant associations were restricted to individuals with no family history. When classifying pesticides by functional type, both insecticides and herbicides were found to significantly increase risk of PD. Two specific insecticide classes, organochlorines and organophosphorus compounds, were significantly associated with PD. Consuming well-water and living/working on a farm were not associated with PD. Conclusion These data corroborate positive associations of broadly defined pesticide exposure with PD in families, particularly for sporadic PD. These data also implicate a few specific classes of pesticides in PD and thus emphasize the need to consider a more narrow definition of pesticides in future studies.

  5. CT-automatic exposure control devices: What are their performances?

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez, Daniel [University Institute for Radiation Physics (IRA-DUMSC), Grand-Pre 1, CH-1007 Lausanne (Switzerland); Schmidt, Sabine; Denys, Alban; Schnyder, Pierre [Radiology Department, University Hospital of Lausanne, CHUV, CH-1011 Lausanne (Switzerland); Bochud, Francois O. [University Institute for Radiation Physics (IRA-DUMSC), Grand-Pre 1, CH-1007 Lausanne (Switzerland); Verdun, Francis R. [University Institute for Radiation Physics (IRA-DUMSC), Grand-Pre 1, CH-1007 Lausanne (Switzerland)], E-mail: francis.verdun@chuv.ch

    2007-10-01

    Purpose: To avoid unnecessary exposure to the patients, constructors have developed tube current modulation algorithms. The purpose of this work is to assess the performance of computed tomography (CT) tube current modulation concerning patient dose and image noise in MSCT scanners. Material and methods: A conical PMMA phantom with elliptical cross-section, to vary the thickness of the irradiated object in a monotonous way, and an anthropomorphic chest phantom were scanned under similar conditions on a general electrics (GE) LightSpeed VCT (64 slices) scanner. Noise measurements were made by calculating the standard deviation of the CT-number on a homogeneous ROI in both phantoms. The dose was estimated with the parameters read in the DICOM header of each studied image. Results: The study has shown that most of the time, constant noise levels (noise index) can be obtained by a variation of the mA. Nevertheless, this adaptation can be not fast enough when the variation of the attenuation changes is rapid. Thus, an adaptation length up to 5 cm was obtained. A 18% dose reduction can be achieved (mean of 9.9%) by switching from z-axis modulation algorithm to xyz-axis modulation option. However, exposure in the chest area can be higher with current modulation than without, when trying to keep an image noise level constant in thoraco-abdominal investigations. Conclusion: Current modulation algorithms can produce inadequate quality images due to problems with tube current stabilization when a sudden attenuation variation takes place as at the start of a scanning sequence. As expected, rotational (xyz-axis) modulation performs better than only z-axis modulation algorithm. The use of automatic exposure control (AEC) can lead to an increase of the dose if the maximum allowed current is not properly set in thoraco-abdominal acquisitions.

  6. Controlling exposure to DPM : diesel particulate filters vs. biodiesel

    International Nuclear Information System (INIS)

    Bugarski, A.D.; Shi, X.C.

    2009-01-01

    In order to comply with Mine Safety and Health Administration regulations, mining companies are required to reduce miners exposures to diesel particulate matter (DPM) to 160 μg/m 3 of total carbon. Diesel particulate filter (DPF) systems, disposable filter elements (DFEs), and diesel oxidation catalysts (DOCs) are among the most effective strategies and technologies for curtailing DPM at its source. Substituting diesel fuel with biodiesel blends is also considered to be a plausible solution by many underground mine operators. Studies were conducted at the National Institute for Occupational Safety and Health Diesel Laboratory at Lake Lynn Experimental Mine to evaluate various control technologies and strategies available to the underground mining industry to reduce exposure to DPM. The physical, chemical and toxicological properties of diesel aerosols (DPM) emitted by engines in an underground mine were also evaluated. The DPF and DFE systems were found to be highly effective in reducing total particulate and elemental carbon mass concentrations, total aerosol surface concentrations and, in most cases, concentrations of diesel aerosols in occupational settings such as underground mines. Soy methyl ester (SME) biodiesel fuels had the potential to reduce the mine air concentrations of total DPM, although the rate of reduction varied depending on engine operating conditions. The disadvantage of using biodiesel fuels was an increase in the fraction of particle-bound volatile organics and concentration of aerosols for light-load engine operating conditions.

  7. Prospective study of leptospirosis transmission in an urban slum community: role of poor environment in repeated exposures to the Leptospira agent.

    Science.gov (United States)

    Felzemburgh, Ridalva D M; Ribeiro, Guilherme S; Costa, Federico; Reis, Renato B; Hagan, José E; Melendez, Astrid X T O; Fraga, Deborah; Santana, Francisco S; Mohr, Sharif; dos Santos, Balbino L; Silva, Adriano Q; Santos, Andréia C; Ravines, Romy R; Tassinari, Wagner S; Carvalho, Marília S; Reis, Mitermayer G; Ko, Albert I

    2014-01-01

    Leptospirosis has emerged as an urban health problem as slum settlements have rapidly spread worldwide and created conditions for rat-borne transmission. Prospective studies have not been performed to determine the disease burden, identify risk factors for infection and provide information needed to guide interventions in these marginalized communities. We enrolled and followed a cohort of 2,003 residents from a slum community in the city of Salvador, Brazil. Baseline and one-year serosurveys were performed to identify primary and secondary Leptospira infections, defined as respectively, seroconversion and four-fold rise in microscopic agglutination titers. We used multinomial logistic regression models to evaluate risk exposures for acquiring primary and secondary infection. A total of 51 Leptospira infections were identified among 1,585 (79%) participants who completed the one-year follow-up protocol. The crude infection rate was 37.8 per 1,000 person-years. The secondary infection rate was 2.3 times higher than that of primary infection rate (71.7 and 31.1 infections per 1,000 person-years, respectively). Male gender (OR 2.88; 95% CI 1.40-5.91) and lower per capita household income (OR 0.54; 95% CI, 0.30-0.98 for an increase of $1 per person per day) were independent risk factors for primary infection. In contrast, the 15-34 year age group (OR 10.82, 95% CI 1.38-85.08), and proximity of residence to an open sewer (OR 0.95; 0.91-0.99 for an increase of 1 m distance) were significant risk factors for secondary infection. This study found that slum residents had high risk (>3% per year) for acquiring a Leptospira infection. Re-infection is a frequent event and occurs in regions of slum settlements that are in proximity to open sewers. Effective prevention of leptospirosis will therefore require interventions that address the infrastructure deficiencies that contribute to repeated exposures among slum inhabitants.

  8. [A case-control study of factors associated with repeat teen pregnancy based on a sample from a university maternity hospital].

    Science.gov (United States)

    Silva, Andréa de Albuquerque Arruda; Coutinho, Isabela C; Katz, Leila; Souza, Alex Sandro Rolland

    2013-03-01

    Repeat teen pregnancy is a frequent issue and is considered an aggravating factor for increased maternal and fetal morbidity and social problems. The aim of the study was to identify factors associated with repeat teen pregnancy. A case-control study was conducted in 90 postpartum adolescents with more than one pregnancy (cases) and 90 adult women with a history of only one pregnancy during adolescence (controls). Statistical analysis used hierarchical logistic regression with 5% significance. Early sexual initiation (pregnancy (pregnancy, while partner change was inversely associated. Repeat teen pregnancy was mainly associated with reproductive and socioeconomic factors. Partner change appeared as a protective factor. Measures should be adopted during the postpartum period of teenage mothers in order to avoid repeat pregnancy.

  9. Preferential induction of the AhR gene battery in HepaRG cells after a single or repeated exposure to heterocyclic aromatic amines

    International Nuclear Information System (INIS)

    Dumont, Julie; Josse, Rozenn; Lambert, Carine; Antherieu, Sebastien; Laurent, Veronique; Loyer, Pascal; Robin, Marie-Anne; Guillouzo, Andre

    2010-01-01

    2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) and 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) are two of the most common heterocyclic aromatic amines (HAA) produced during cooking of meat, fish and poultry. Both HAA produce different tumor profiles in rodents and are suspected to be carcinogenic in humans. In order to better understand the molecular basis of HAA toxicity, we have analyzed gene expression profiles in the metabolically competent human HepaRG cells using pangenomic oligonucleotide microarrays, after either a single (24-h) or a repeated (28-day) exposure to 10 μM PhIP or MeIQx. The most responsive genes to both HAA were downstream targets of the arylhydrocarbon receptor (AhR): CYP1A1 and CYP1A2 after both time points and CYP1B1 and ALDH3A1 after 28 days. Accordingly, CYP1A1/1A2 induction in HAA-treated HepaRG cells was prevented by chemical inhibition or small interference RNA-mediated down-regulation of the AhR. Consistently, HAA induced activity of the CYP1A1 promoter, which contains a consensus AhR-related xenobiotic-responsive element (XRE). In addition, several other genes exhibited both time-dependent and compound-specific expression changes with, however, a smaller magnitude than previously reported for the prototypical AhR target genes. These changes concerned genes mainly related to cell growth and proliferation, apoptosis, and cancer. In conclusion, these results identify the AhR gene battery as the preferential target of PhIP and MeIQx in HepaRG cells and further support the hypothesis that intake of HAA in diet might increase human cancer risk.

  10. Repeated in vivo exposure of cocaine induces long-lasting synaptic plasticity in hypocretin/orexin-producing neurons in the lateral hypothalamus in mice.

    Science.gov (United States)

    Rao, Yan; Mineur, Yann S; Gan, Geliang; Wang, Alex Hanxiang; Liu, Zhong-Wu; Wu, Xinyuan; Suyama, Shigetomo; de Lecea, Luis; Horvath, Tamas L; Picciotto, Marina R; Gao, Xiao-Bing

    2013-04-01

    Hypocretin (orexin), a neuropeptide synthesized exclusively in the perifornical/lateral hypothalamus, is critical for drug seeking and relapse, but it is not clear how the circuitry centred on hypocretin-producing neurons (hypocretin neurons) is modified by drugs of abuse and how changes in this circuit might alter behaviours related to drug addiction. In this study, we show that repeated, but not single, in vivo cocaine administration leads to a long-lasting, experience-dependent potentiation of glutamatergic synapses on hypocretin neurons in mice following a cocaine-conditioned place preference (CPP) protocol. The synaptic potentiation occurs postsynaptically and probably involves up-regulation of AMPA-type glutamate receptors on hypocretin neurons. Phosphorylation of cAMP response element-binding protein (CREB) is also significantly increased in hypocretin neurons in cocaine-treated animals, suggesting that CREB-mediated pathways may contribute to synaptic potentiation in these cells. Furthermore, the potentiation of synaptic efficacy in hypocretin neurons persists during cocaine withdrawal, but reverses to baseline levels after prolonged abstinence. Finally, the induction of long-term potentiation (LTP) triggered by a high-frequency stimulation is facilitated in hypocretin neurons in cocaine-treated mice, suggesting that long-lasting changes in synapses onto hypocretin neurons would probably be further potentiated by other stimuli (such as concurrent environmental cues) paired with the drug. In summary, we show here that hypocretin neurons undergo experience-dependent synaptic potentiation that is distinct from that reported in other reward systems, such as the ventral tegmental area, following exposure to cocaine. These findings support the idea that the hypocretin system is important for behavioural changes associated with cocaine administration in animals and humans.

  11. To describe and control exposure in nanoecotoxicology tests

    DEFF Research Database (Denmark)

    Baun, Anders

    are fulfilling the purpose they originally were intended for (ranking and classification). The validity of extrapolations made from these data (e.g. predicted no-effect concentrations for environmental risk assessments) is therefore further questionable. Based on own experiences these fundamental problems......There is an urgent need for reliable and reproducible results of ecotoxicological experiments in order to identify, rank, and classify the environmental hazards of nanomaterials. Standardized methods and guideline tests traditionally used for chemicals are today recommended for the testing...... of nanomaterials. While the database of results from these tests is rapidly expanding, problems with controlling the exposure are often reported, e.g. due to the particle behavior in the test media used. Problems encountered include uncontrollable aggregation, agglomeration, sedimentation, or dissolution...

  12. Tocolysis for repeat external cephalic version in breech presentation at term: a randomised, double-blinded, placebo-controlled trial.

    Science.gov (United States)

    Impey, Lawrence; Pandit, Meghana

    2005-05-01

    External cephalic version (ECV) reduces the incidence of breech presentation at term and caesarean section for non-cephalic births. Tocolytics may improve success rates, but are time consuming, may cause side effects and have not been proven to alter caesarean section rates. The aim of this trial was to determine whether tocolysis should be used if ECV is being re-attempted after a failed attempt. To determine whether tocolysis should be used if ECV is being re-attempted after a failed attempt. Randomised, double-blinded, placebo-controlled trial. UK teaching hospital. One hundred and twenty-four women with a breech presentation at term who had undergone an unsuccessful attempt at ECV. Relative risks with 95% confidence intervals for categorical variables and a t test for continuous variables. Analysis was by intention to treat. Incidence of cephalic presentation at delivery. Secondary outcomes were caesarean section and measures of neonatal and maternal morbidity. The use of tocolysis for a repeat attempt at ECV significantly increases the incidence of cephalic presentation at delivery (RR 3.21; 95% CI 1.23-8.39) and reduces the incidence of caesarean section (RR 0.33; 95% CI 0.14-0.80). The effects were most marked in multiparous women (RR for cephalic presentation at delivery 9.38; 95% CI 1.64-53.62). Maternal and neonatal morbidity remain unchanged. The use of tocolysis increases the success rate of repeat ECV and reduces the incidence of caesarean section. A policy of only using tocolysis where an initial attempt has failed leads to a relatively high success rate with minimum usage of tocolysis.

  13. Dataset of acute repeated sessions of bifrontal transcranial direct current stimulation for treatment of intractable tinnitus: A randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Ali Yadollahpour

    2017-12-01

    Full Text Available Transcranial direct current stimulation (tDCS has reportedly shown promising therapeutic effects for tinnitus (Forogh et al., 2016; Joos et al., 2014 [1,2]. Studies are ongoing to determine optimum treatment protocol and the site of stimulation. Findings of the early studies are heterogeneous and most studies have focused on single session tDCS and short follow-up periods. There is no study on repeated sessions of tDCS with long term follow-up. This study presents the results of a randomized clinical trial investigating the therapeutic effects of acute multi-session tDCS over dorsolateral prefrontal cortex (DLPFC on tinnitus symptoms and comorbid depression and anxiety in patients with chronic intractable tinnitus. The dataset includes the demographic information, audiometric assessments, tinnitus specific characteristics, and the response variables of the study. The response variables included the scores of tinnitus handicap inventory (THI, tinnitus loudness and tinnitus related distress based on 0–10 numerical visual analogue scale (VAS scores, beck depression inventory (BDI-II and beck anxiety inventory (BAI scores. The dataset included the scores of THI pre and immediately post intervention, and at one month follow-up; the tinnitus loudness and distress scores prior to intervention, and immediately, one hour, one week, and at one month after the last stimulation session. In addition, the BDI-II, and BAI scores pre and post intervention are included. The data of the real (n=25 and sham tDCS (n=17 groups are reported. The main manuscript of this dataset is 'Acute repeated sessions of bifrontal transcranial direct current stimulation for treatment of intractable tinnitus: a randomized controlled trial' (Bayat et al., submitted for publication [3]. Keywords: Transcranial direct current stimulation, Acute stimulations, Tinnitus, Depression, Anxiety, DLPFC

  14. PTSD and DNA Methylation in Select Immune Function Gene Promoter Regions: A Repeated Measures Case-control Study of U.S. Military Service Members

    Science.gov (United States)

    2013-06-24

    other relevant exposures which may influ- ence DNA methylation , such as dietary factors ( folate , vitamin B12 intake) (Fenech, 2001; Piyathilake and...ARTICLE published: 24 June 2013 doi: 10.3389/fpsyt.2013.00056 PTSD and DNA methylation in select immune function gene promoter regions: a repeated measures...largely unknown. Dis- tinct expression signatures for PTSD have been found, in particular for immune activation transcripts. DNA methylation may be

  15. Regulatory Strategy to Control Radon Exposure in Pakistan

    International Nuclear Information System (INIS)

    Younus, Irfan; Cho, Kun Woo

    2012-01-01

    Pakistan Nuclear Regulatory Authority (PNRA) was established in 2001 with one of the objectives to ensure the protection of workers, general public and the environment from the harmful effects of naturally occurring and artificially produced ionizing radiations by formulating and implementing the effective regulations. Radon is a naturally occurring odorless, colorless, tasteless, imperceptible to senses and chemically inert radioactive gas which is produced continuously from the natural decay of U-238, U-235 and Th-232 in most soils, rocks and water all over the earth. High levels of radon in the soil and rock are primarily responsible for indoor radon problems. Therefore when inhaled with air, there much probability that radon decay products will stay and decay in the lungs. If stayed in the lungs, the radiation may damage the cells causing lung cancer. Hence the radon problems have been taken seriously in most of the developed countries of the world. Radon reference levels for dwellings and workplaces have been set and the general public has been made alert of radon through newspapers and electronic media. In Pakistan, neither publicity campaign nor radon measurement and control programmes have been started countrywide. Rather small individual efforts for the sake of interest have been done to investigate the radon in some specific area or institution. This paper presents the regulatory strategy to control radon exposure for the sake of radiation protection of public and workers in Pakistan

  16. A randomised controlled trial of repeated filmed social contact on reducing mental illness-related stigma in young adults.

    Science.gov (United States)

    Koike, S; Yamaguchi, S; Ojio, Y; Ohta, K; Shimada, T; Watanabe, K; Thornicroft, G; Ando, S

    2018-04-01

    Public stigma alters attitudes towards people with mental illness, and is a particular concern for young people since most mental health problems occur in adolescence and young adulthood. However, little is known about the long-term effects of repeated filmed social contact (FSC) on reducing mental health-related stigma among young adults in the general population, compared with self-instructional Internet search (INS) and control interventions. This study is a parallel-group randomised controlled trial over 12 months conducted in Tokyo, Japan. A total of 259 university students (male n = 150, mean age = 20.0 years, s.d. = 1.2) were recruited from 20 colleges and universities between November 2013 and July 2014, without being provided information about the mental health-related survey or trial. Participants were assigned to one of three groups before completion of the baseline survey (FSC/INS/control = 89/83/87). The FSC group received a computer-based 30-min social contact film with general mental health education and five follow-up web-based FSCs at 2-month intervals. The INS group undertook a 30-min search for mental health-related information with five follow-up web-based reminders for self-instructional searches at 2-month intervals. The control group played PC games and had no follow-up intervention. The main outcome measures were the future (intended behaviour) domain of the Reported and Intended Behaviour Scale at 12 months after the intervention. Analysis was conducted in September 2015. At the 12-month follow-up, 218 participants completed the survey (84.1%, 75:70:73). The FSC group showed the greatest change at the 12-month follow-up (FSC: mean change 2.11 [95% CI 1.49, 2.73], INS: 1.04 [0.29, 1.80], control: 0.71 [0.09, 1.33]; FSC v. INS p = 0.037, FSC v. controls p = 0.004). No adverse events were reported during the follow-up period. FSC was more successful in reducing stigma at 12 months after intervention than INS or control interventions. FSC could

  17. Hexavalent chromium exposures and exposure-control technologies in American enterprise: results of a NIOSH field research study.

    Science.gov (United States)

    Blade, L M; Yencken, M Story; Wallace, M E; Catalano, J D; Khan, A; Topmiller, J L; Shulman, S A; Martinez, A; Crouch, K G; Bennett, J S

    2007-08-01

    The National Institute for Occupational Safety and Health (NIOSH) conducted 21 field surveys in selected industries to characterize workers' exposures to hexavalent chromium-containing airborne particulate and to evaluate existing technologies for controlling these exposures. Hexavalent chromium Cr(VI) is a respiratory irritant and chronic inhalation may cause lung cancer. Primary evaluation methods included collection of full work shift, personal breathing-zone (PBZ) air samples for Cr(VI), measurement of ventilation system parameters, and documentation of processes and work practices. This study emphasized evaluation of engineering exposure control measures, so PBZ exposures were measured on the outside of personal protective equipment, for example, respirators. Field surveys were conducted in two chromium electroplating facilities, including one where full-shift PBZ exposures to Cr(VI) ranged from 3.0 to 16 times the 1 micro g/m(3)NIOSH recommended exposure limit (REL) despite several engineering controls on the plating tanks. At a painting and coating facility that used Cr(VI)-containing products, full-shift exposures of painters and helpers (2.4 to 55 micro g/m(3)) exceeded the REL, but LEV effectiveness was limited. Other operations evaluated included welding in construction; metal cutting operations on chromium-containing materials in ship breaking; chromate-paint removal with abrasive blasting; atomized alloy-spray coating; foundry operations; printing; and the manufacture of refractory brick, colored glass, prefabricated concrete products, and treated wood products. NIOSH researchers concluded that, in many of the evaluated processes, Cr(VI) exposures at or below the current NIOSH REL are achievable. However, for some processes, it is unclear whether controlling exposures to this range is consistently achievable without respirator use. Some operations involving the application of coatings and finishes may be among those most difficult to control to this

  18. School-based intervention with children. Peer-modeling, reward and repeated exposure reduce food neophobia and increase liking of fruits and vegetables.

    Science.gov (United States)

    Laureati, Monica; Bergamaschi, Valentina; Pagliarini, Ella

    2014-12-01

    This study investigated the effectiveness of the 'Food Dudes' school-based intervention consisting of rewards, peer-modeling and food exposure on food neophobia and the liking of fruits and vegetables (FV) in a large cohort of children. Five-hundred sixty children recruited from three schools were assigned to the experimental or control group. For 16 days, children in the experimental group watched motivational videos, were read letters to encourage them to eat FV and received a small reward for eating one portion of both a fruit and a vegetable. The control group was only provided with FV for the same time period. Food neophobia and liking were measured in both groups of children before and after the intervention, and a follow-up measurement was carried out 6 months later. The intervention was effective in reducing food neophobia and, most importantly, a persistent effect was observed 6 months after the intervention as children of the experimental group showed significantly lower neophobia scores than the control group. Additionally, the program was effective in increasing liking for both FV; however, this effect was maintained only for fruit after 6 months. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Application of a pilot control banding tool for risk level assessment and control of nanoparticle exposures.

    Science.gov (United States)

    Paik, Samuel Y; Zalk, David M; Swuste, Paul

    2008-08-01

    Control banding (CB) strategies offer simplified solutions for controlling worker exposures to constituents that are found in the workplace in the absence of firm toxicological and exposure data. These strategies may be particularly useful in nanotechnology applications, considering the overwhelming level of uncertainty over what nanomaterials and nanotechnologies present as potential work-related health risks, what about these materials might lead to adverse toxicological activity, how risk related to these might be assessed and how to manage these issues in the absence of this information. This study introduces a pilot CB tool or 'CB Nanotool' that was developed specifically for characterizing the health aspects of working with engineered nanoparticles and determining the level of risk and associated controls for five ongoing nanotechnology-related operations being conducted at two Department of Energy research laboratories. Based on the application of the CB Nanotool, four of the five operations evaluated in this study were found to have implemented controls consistent with what was recommended by the CB Nanotool, with one operation even exceeding the required controls for that activity. The one remaining operation was determined to require an upgrade in controls. By developing this dynamic CB Nanotool within the realm of the scientific information available, this application of CB appears to be a useful approach for assessing the risk of nanomaterial operations, providing recommendations for appropriate engineering controls and facilitating the allocation of resources to the activities that most need them.

  20. Predictive value of repeated measurements of luteal progesterone and estradiol levels in patients with intrauterine insemination and controlled ovarian stimulation.

    Science.gov (United States)

    Bakas, Panagiotis; Simopoulou, Maria; Giner, Maria; Drakakis, Petros; Panagopoulos, Perikles; Vlahos, Nikolaos

    2017-10-01

    The objective of this study is to assess if the difference of repeated measurements of estradiol and progesterone during luteal phase predict the outcome of intrauterine insemination. Prospective study. Reproductive clinic. 126 patients with infertility. Patients underwent controlled ovarian stimulation with recombinant FSH (50-150 IU/d). The day of IUI patients were given p.o natural micronized progesterone in a dose of 100 mg/tds. The area under the receiver characteristic operating curve (ROC curve) in predicting clinical pregnancy for % change of estradiol level on days 6 and 10 was 0.892 with 95% CI: 0.82-0.94. A cutoff value of change > -29.5% had a sensitivity of 85.7 with a specificity of 90.2. The corresponding ROC curve for % change of progesterone level was 0.839 with 95% CI: 0.76-0.90. A cutoff value of change > -33% had a sensitivity of 85 with a specificity of 75. The % change of estradiol and progesterone between days 6 and 10 has a predictive ability of pregnancy after IUI with COS of 89.2% and 83.4%, respectively. The addition of % of progesterone to % change of estradiol does not improve the predictive ability of % estradiol and should not be used.

  1. [Analytical procedure of variable number of tandem repeats (VNTR) analysis and effective use of analysis results for tuberculosis control].

    Science.gov (United States)

    Hachisu, Yushi; Hashimoto, Ruiko; Kishida, Kazunori; Yokoyama, Eiji

    2013-12-01

    Variable number of tandem repeats (VNTR) analysis is one of the methods for molecular epidemiological studies of Mycobacterium tuberculosis. VNTR analysis is a method based on PCR, provides rapid highly reproducible results and higher strain discrimination power than the restriction fragment length polymorphism (RFLP) analysis widely used in molecular epidemiological studies of Mycobacterium tuberculosis. Genetic lineage compositions of Mycobacterium tuberculosis clinical isolates differ among the regions from where they are isolated, and allelic diversity at each locus also differs among the genetic lineages of Mycobacterium tuberculosis. Therefore, the combination of VNTR loci that can provide high discrimination capacity for analysis is not common in every region. The Japan Anti-Tuberculosis Association (JATA) 12 (15) reported a standard combination of VNTR loci for analysis in Japan, and the combination with hypervariable (HV) loci added to JATA12 (15), which has very high discrimination capacity, was also reported. From these reports, it is thought that data sharing between institutions and construction of a nationwide database will progress from now on. Using database construction of VNTR profiles, VNTR analysis has become an effective tool to trace the route of tuberculosis infection, and also helps in decision-making in the treatment course. However, in order to utilize the results of VNTR analysis effectively, it is important that each related organization cooperates closely, and analysis should be appropriately applied in the system in which accurate control and private information protection are ensured.

  2. Repeating Marx

    DEFF Research Database (Denmark)

    Fuchs, Christian; Monticelli, Lara

    2018-01-01

    This introduction sets out the context of the special issue “Karl Marx @ 200: Debating Capitalism & Perspectives for the Future of Radical Theory”, which was published on the occasion of Marx’s bicentenary on 5 May 2018. First, we give a brief overview of contemporary capitalism’s development...... and its crises. Second, we argue that it is important to repeat Marx today. Third, we reflect on lessons learned from 200 years of struggles for alternatives to capitalism. Fourth, we give an overview of the contributions in this special issue. Taken together, the contributions in this special issue show...... that Marx’s theory and politics remain key inspirations for understanding exploitation and domination in 21st-century society and for struggles that aim to overcome these phenomena and establishing a just and fair society. We need to repeat Marx today....

  3. Deployment Repeatability

    Science.gov (United States)

    2016-08-31

    large cohort of trials to spot unusual cases. However, deployment repeatability is inherently a nonlinear phenomenon, which makes modeling difficult...and GEMS tip position were both tracked during ground testing by a laser target tracking system. Earlier SAILMAST testing in 2005 [8] used...recalls the strategy used by SRTM, where a constellation of lights was installed at the tip of the boom and a modified star tracker was used to track tip

  4. Assessment of the Effects of Acute and Repeated Exposure to Blast Overpressure in Rodents: Towards a Greater Understanding of Blast and the Potential Ramifications for Injury in Humans Exposed to Blast

    Directory of Open Access Journals (Sweden)

    Stephen Thomas Ahlers

    2012-03-01

    Full Text Available Mild traumatic brain injury (mTBI resulting from exposure to improvised explosive devices (IEDs has fueled a requirement to develop animals models that mirror this condition using exposure to blast overpressure (BOP. En route to developing a model of repeated exposure to BOP we sought to initially characterize the effects of acute BOP exposure in rodents, focusing specifically on the levels of BOP exposure that produced clinical mTBI symptoms. We first measured BOP effects on gross motor function on a balance beam. Separate groups of unanesthetized rats were exposed (in different orientations to 40 kPa, 75 kPa and 120 kPa BOP exposure inside a pneumatically driven shock tube. Results demonstrated that rats exposed to 120 kPa demonstrated transient alterations or loss of consciousness indicated by a transient loss of righting and by increased latencies on the balance beam. The 120 kPa exposure was the threshold for overt pathology for acute BOP exposure with approximately 30% of rats presenting with evidence of subdural hemorrhage and cortical contusions. All animals exposed to 120 kPa BOP manifested evidence of significant pulmonary hemorrhage. Anterograde memory deficits were observed in rats exposed to 75 kPa facing the BOP wave and rats exposed to 120 kPa in the lateral (side orientation. We next assessed repeated exposure to either lateral or frontal 40 kPa BOP in anesthetized rats, once per day for 12 days. Results showed that repeated exposure in the frontal, but not side, orientation to the BOP wave produced a transitory learning deficit on a Morris water maze (MWM task as shown by significantly longer latencies to reach the submerged platform in the second and third blocks of a four block session. Implications of these data are discussed in relation to the manifestation of mTBI in military personnel exposed to IEDs. Finally, we suggest that there are multiple types of brain injury from blast.

  5. Female gonadal shielding with automatic exposure control increases radiation risks

    Energy Technology Data Exchange (ETDEWEB)

    Kaplan, Summer L.; Zhu, Xiaowei [Children' s Hospital of Philadelphia, Department of Radiology, Philadelphia, PA (United States); University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA (United States); Magill, Dennise; Felice, Marc A. [University of Pennsylvania, Environmental Health and Radiation Safety, Philadelphia, PA (United States); Xiao, Rui [University of Pennsylvania, Department of Biostatistics and Epidemiology, Philadelphia, PA (United States); Ali, Sayed [Temple University Hospital, Department of Radiology, Philadelphia, PA (United States)

    2018-02-15

    Gonadal shielding remains common, but current estimates of gonadal radiation risk are lower than estimated risks to colon and stomach. A female gonadal shield may attenuate active automatic exposure control (AEC) sensors, resulting in increased dose to colon and stomach as well as to ovaries outside the shielded area. We assess changes in dose-area product (DAP) and absorbed organ dose when female gonadal shielding is used with AEC for pelvis radiography. We imaged adult and 5-year-old equivalent dosimetry phantoms using pelvis radiograph technique with AEC in the presence and absence of a female gonadal shield. We recorded DAP and mAs and measured organ absorbed dose at six internal sites using film dosimetry. Female gonadal shielding with AEC increased DAP 63% for the 5-year-old phantom and 147% for the adult phantom. Absorbed organ dose at unshielded locations of colon, stomach and ovaries increased 21-51% in the 5-year-old phantom and 17-100% in the adult phantom. Absorbed organ dose sampled under the shield decreased 67% in the 5-year-old phantom and 16% in the adult phantom. Female gonadal shielding combined with AEC during pelvic radiography increases absorbed dose to organs with greater radiation sensitivity and to unshielded ovaries. Difficulty in proper use of gonadal shields has been well described, and use of female gonadal shielding may be inadvisable given the risks of increasing radiation. (orig.)

  6. Female gonadal shielding with automatic exposure control increases radiation risks

    International Nuclear Information System (INIS)

    Kaplan, Summer L.; Zhu, Xiaowei; Magill, Dennise; Felice, Marc A.; Xiao, Rui; Ali, Sayed

    2018-01-01

    Gonadal shielding remains common, but current estimates of gonadal radiation risk are lower than estimated risks to colon and stomach. A female gonadal shield may attenuate active automatic exposure control (AEC) sensors, resulting in increased dose to colon and stomach as well as to ovaries outside the shielded area. We assess changes in dose-area product (DAP) and absorbed organ dose when female gonadal shielding is used with AEC for pelvis radiography. We imaged adult and 5-year-old equivalent dosimetry phantoms using pelvis radiograph technique with AEC in the presence and absence of a female gonadal shield. We recorded DAP and mAs and measured organ absorbed dose at six internal sites using film dosimetry. Female gonadal shielding with AEC increased DAP 63% for the 5-year-old phantom and 147% for the adult phantom. Absorbed organ dose at unshielded locations of colon, stomach and ovaries increased 21-51% in the 5-year-old phantom and 17-100% in the adult phantom. Absorbed organ dose sampled under the shield decreased 67% in the 5-year-old phantom and 16% in the adult phantom. Female gonadal shielding combined with AEC during pelvic radiography increases absorbed dose to organs with greater radiation sensitivity and to unshielded ovaries. Difficulty in proper use of gonadal shields has been well described, and use of female gonadal shielding may be inadvisable given the risks of increasing radiation. (orig.)

  7. Female gonadal shielding with automatic exposure control increases radiation risks.

    Science.gov (United States)

    Kaplan, Summer L; Magill, Dennise; Felice, Marc A; Xiao, Rui; Ali, Sayed; Zhu, Xiaowei

    2018-02-01

    Gonadal shielding remains common, but current estimates of gonadal radiation risk are lower than estimated risks to colon and stomach. A female gonadal shield may attenuate active automatic exposure control (AEC) sensors, resulting in increased dose to colon and stomach as well as to ovaries outside the shielded area. We assess changes in dose-area product (DAP) and absorbed organ dose when female gonadal shielding is used with AEC for pelvis radiography. We imaged adult and 5-year-old equivalent dosimetry phantoms using pelvis radiograph technique with AEC in the presence and absence of a female gonadal shield. We recorded DAP and mAs and measured organ absorbed dose at six internal sites using film dosimetry. Female gonadal shielding with AEC increased DAP 63% for the 5-year-old phantom and 147% for the adult phantom. Absorbed organ dose at unshielded locations of colon, stomach and ovaries increased 21-51% in the 5-year-old phantom and 17-100% in the adult phantom. Absorbed organ dose sampled under the shield decreased 67% in the 5-year-old phantom and 16% in the adult phantom. Female gonadal shielding combined with AEC during pelvic radiography increases absorbed dose to organs with greater radiation sensitivity and to unshielded ovaries. Difficulty in proper use of gonadal shields has been well described, and use of female gonadal shielding may be inadvisable given the risks of increasing radiation.

  8. 78 FR 68447 - Exposure Draft-Standards for Internal Control in the Federal Government

    Science.gov (United States)

    2013-11-14

    ... GOVERNMENT ACCOUNTABILITY OFFICE Exposure Draft--Standards for Internal Control in the Federal... revisions to the Standards for Internal Control in the Federal Government, known as the ``Green Book,'' to... proposed changes contained in the 2013 Exposure Draft update to the Standards for Internal Control in the...

  9. Simultaneous Control of Phenanthrene and Drought by Dual Exposure System

    DEFF Research Database (Denmark)

    Schmidt, Stine N.; Holmstrup, Martin; Damgaard, Christian

    2014-01-01

    Organisms in the environment are exposed to multiple stressors. However, for terrestrial invertebrates, it remains difficult to study the effects of combined stressors under well-defined exposure conditions. Thus, the current study develops a new dual exposure system for the simultaneous...... set revealed statistically significant synergy between phenanthrene and drought (p account when...

  10. A review of automatic exposure control of conventional and digital systems

    International Nuclear Information System (INIS)

    Workman, A.; Cowen, A.R.

    1989-01-01

    The desirable properties and methods of achieving automatic exposure control in film-screen radiography, fluoroscopy, spot-film fluorography and cinefluorography are discussed. Advantages of certain methods in achieving optimum image quality for minimal patient exposure are considered. In digital subtraction fluorography (DSF) where relatively large exposure levels per image are used, proper set-up of exposure conditions is of particular importance. These systems require a high degree of stability in exposure to maintain a high level of image quality. We have developed test methods for monitoring the set-up and reproducibility of exposure levels in DSF. (author)

  11. Reconfigurable multiport EPON repeater

    Science.gov (United States)

    Oishi, Masayuki; Inohara, Ryo; Agata, Akira; Horiuchi, Yukio

    2009-11-01

    An extended reach EPON repeater is one of the solutions to effectively expand FTTH service areas. In this paper, we propose a reconfigurable multi-port EPON repeater for effective accommodation of multiple ODNs with a single OLT line card. The proposed repeater, which has multi-ports in both OLT and ODN sides, consists of TRs, BTRs with the CDR function and a reconfigurable electrical matrix switch, can accommodate multiple ODNs to a single OLT line card by controlling the connection of the matrix switch. Although conventional EPON repeaters require full OLT line cards to accommodate subscribers from the initial installation stage, the proposed repeater can dramatically reduce the number of required line cards especially when the number of subscribers is less than a half of the maximum registerable users per OLT. Numerical calculation results show that the extended reach EPON system with the proposed EPON repeater can save 17.5% of the initial installation cost compared with a conventional repeater, and can be less expensive than conventional systems up to the maximum subscribers especially when the percentage of ODNs in lightly-populated areas is higher.

  12. Evaluation of repeated bio disinfestation using Brassica carinata pellets to control Meloidogyne incognita in protected pepper crops

    Energy Technology Data Exchange (ETDEWEB)

    Guerrero-Diaz, M. M.; Lacasa-Martinez, C. M.; Hernandez-Pinera, A.; Martinez-Alarcon, V.; Lacasa Plasencia, A.

    2013-06-01

    The nematode Meloidogyne incognita is responsible for substantial losses in greenhouse-grown peppers in southeastern Spain. This study evaluates the use of biodisinfestation (BS) (organic amendment + solarisation) as an alternative to using methyl bromide (MB) over three consecutive years to control the nematode in greenhouse conditions. Brassica carinata (BP) pellets or B. carinata (BP) + fresh sheep manure (M) were evaluated in treatments which began on two different dates (August and October) and the results were compared with MB-disinfested and untreated controls. During the third year, the gall index for BP was lower than that obtained for BP +M and in the August treatment than in the October treatment. The commercial crop of pepper fruit obtained with the biodisinfestation treatments begun in August was similar to or higher than that obtained with MB, and higher than that obtained with both October biodisinfestation treatments. The yield of the October biodisinfestation treatments was higher than that of the untreated one. In August of all the years studied, the accumulated exposure times were greater than the thresholds required to kill M. incognita populations at 15 cm depth. The incidence of the nematode did not correspond to the reduction achieved during solarisation, and seemed to increase during the crop cycle. Further studies should look at why high temperatures do not produce a sustained reduction in the populations of Meloidogyne incognita. (Author) 56 refs.

  13. Controlling radiation exposure during interventional procedures in childhood cancer patients

    International Nuclear Information System (INIS)

    Racadio, John M.

    2009-01-01

    Many pediatric cancer patients undergo multiple diagnostic and therapeutic radiologic procedures over the course of their illnesses and are therefore at high risk for radiation exposure. There are a variety of measures that radiologists can employ to reduce this risk. These include limiting the use of radiation whenever possible, using specific strategies to reduce radiation exposure during interventional procedures, using quality assurance programs to ensure compliance, and maintaining continuing staff radiation safety educational programs. Some of the diagnostic and therapeutic interventional radiologic procedures that are performed in pediatric oncology patients are discussed here, along with specific tips for managing radiation exposure. (orig.)

  14. Evaluation of automatic exposure control systems in computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Reina, Thamiris Rosado

    2014-07-01

    The development of the computed tomography (CT) technology has brought wider possibilities on diagnostic medicine. It is a non-invasive method to see the human body in details. As the CT application increases, it raises the concern about patient dose, because the higher dose levels imparted compared to other diagnostic imaging modalities. The radiology community (radiologists, medical physicists and manufacturer) are working together to find the lowest dose level possible, without compromising the diagnostic image quality. The greatest and relatively new advance to lower the patient dose is the automatic exposure control (AEC) systems in CT. These systems are designed to ponder the dose distribution along the patient scanning and between patients taking into account their sizes and irradiated tissue densities. Based on the CT scanning geometry, the AEC-systems are very complex and their functioning is yet not fully understood. This work aims to evaluate the clinical performance of AEC-systems and their susceptibilities to assist on possible patient dose optimizations. The approach to evaluate the AEC-systems of three of the leading CT manufacturers in Brazil, General Electric, Philips and Toshiba, was the extraction of tube current modulation data from the DICOM standard image sequences, measurement and analysis of the image noise of those image sequences and measurement of the dose distribution along the scan length on the surface and inside of two different phantoms configurations. The tube current modulation of each CT scanner associated to the resulted image quality provides the performance of the AECsystem. The dose distribution measurements provide the dose profile due to the tube current modulation. Dose measurements with the AEC-system ON and OFF were made to quantify the impact of these systems regarding patient dose. The results attained give rise to optimizations on the AEC-systems applications and, by consequence, decreases the patient dose without

  15. Evaluation of automatic exposure control systems in computed tomography

    International Nuclear Information System (INIS)

    Reina, Thamiris Rosado

    2014-01-01

    The development of the computed tomography (CT) technology has brought wider possibilities on diagnostic medicine. It is a non-invasive method to see the human body in details. As the CT application increases, it raises the concern about patient dose, because the higher dose levels imparted compared to other diagnostic imaging modalities. The radiology community (radiologists, medical physicists and manufacturer) are working together to find the lowest dose level possible, without compromising the diagnostic image quality. The greatest and relatively new advance to lower the patient dose is the automatic exposure control (AEC) systems in CT. These systems are designed to ponder the dose distribution along the patient scanning and between patients taking into account their sizes and irradiated tissue densities. Based on the CT scanning geometry, the AEC-systems are very complex and their functioning is yet not fully understood. This work aims to evaluate the clinical performance of AEC-systems and their susceptibilities to assist on possible patient dose optimizations. The approach to evaluate the AEC-systems of three of the leading CT manufacturers in Brazil, General Electric, Philips and Toshiba, was the extraction of tube current modulation data from the DICOM standard image sequences, measurement and analysis of the image noise of those image sequences and measurement of the dose distribution along the scan length on the surface and inside of two different phantoms configurations. The tube current modulation of each CT scanner associated to the resulted image quality provides the performance of the AECsystem. The dose distribution measurements provide the dose profile due to the tube current modulation. Dose measurements with the AEC-system ON and OFF were made to quantify the impact of these systems regarding patient dose. The results attained give rise to optimizations on the AEC-systems applications and, by consequence, decreases the patient dose without

  16. A preliminary study into performing routine tube output and automatic exposure control quality assurance using radiology information system data

    International Nuclear Information System (INIS)

    Charnock, P.; Jones, R.; Fazakerley, J.; Wilde, R.; Dunn, A. F.

    2011-01-01

    Data are currently being collected from hospital radiology information systems in the North West of the UK for the purposes of both clinical audit and patient dose audit. Could these data also be used to satisfy quality assurance (QA) requirements according to UK guidance? From 2008 to 2009, 731 653 records were submitted from 8 hospitals from the North West England. For automatic exposure control QA, the protocol from Inst. of Physics and Engineering in Medicine (IPEM) report 91 recommends that milli amperes per second can be monitored for repeatability and reproducibility using a suitable phantom, at 70-81 kV. Abdomen AP and chest PA examinations were analysed to find the most common kilo voltage used with these records then used to plot average monthly milli amperes per second with time. IPEM report 91 also recommends that a range of commonly used clinical settings is used to check output reproducibility and repeatability. For each tube, the dose area product values were plotted over time for two most common exposure factor sets. Results show that it is possible to do performance checks of AEC systems; however more work is required to be able to monitor tube output performance. Procedurally, the management system requires work and the benefits to the workflow would need to be demonstrated. (authors)

  17. Effects of Lifetime Occupational Pesticide Exposure on Postural Control Among Farmworkers and Non-Farmworkers.

    Science.gov (United States)

    Sunwook, Kim; Nussbaum, Maury A; Quandt, Sara A; Laurienti, Paul J; Arcury, Thomas A

    2016-02-01

    The aim of the study was to assess potential chronic effects of pesticide exposure on postural control, by examining postural balance of farmworkers and non-farmworkers diverse self-reported lifetime exposures. Balance was assessed during quiet upright stance under four experimental conditions (2 visual × 2 cognitive difficulty). Significant differences in baseline balance performance (eyes open without cognitive task) between occupational groups were apparent in postural sway complexity. When adding a cognitive task to the eyes open condition, the influence of lifetime exposure on complexity ratios appeared different between occupational groups. Removing visual information revealed a negative association of lifetime exposure with complexity ratios. Farmworkers and non-farmworkers may use different postural control strategies even when controlling for the level of lifetime pesticide exposure. Long-term exposure can affect somatosensory/vestibular sensory systems and the central processing of sensory information for postural control.

  18. Nano-metal Oxides: Exposure and Engineering Control Assessment

    OpenAIRE

    Garcia, Alberto; Sparks, Christopher; Martinez, Kenneth; Topmiller, Jennifer L.; Eastlake, Adrienne; Geraci, Charles L.

    2017-01-01

    This paper discusses the evaluation of a facility that produces high quality engineered nanomaterials. These ENMs consist of various metals including iron, nickel, silver, manganese, and palladium. Although occupational exposure levels are not available for these metals, studies have indicated that it may be prudent to keep exposures to the nano-scale metal as low as possible. Previous In vitro studies indicated that in comparison with a material’s larger (parent) counterpart, nanomaterials c...

  19. Health effects of laser printer emissions: a controlled exposure study.

    Science.gov (United States)

    Karrasch, S; Simon, M; Herbig, B; Langner, J; Seeger, S; Kronseder, A; Peters, S; Dietrich-Gümperlein, G; Schierl, R; Nowak, D; Jörres, R A

    2017-07-01

    Ultrafine particles emitted from laser printers are suspected to elicit adverse health effects. We performed 75-minute exposures to emissions of laser printing devices (LPDs) in a standardized, randomized, cross-over manner in 23 healthy subjects, 14 mild, stable asthmatics, and 15 persons reporting symptoms associated with LPD emissions. Low-level exposures (LLE) ranged at the particle background (3000 cm -3 ) and high-level exposures (HLE) at 100 000 cm -3 . Examinations before and after exposures included spirometry, body plethysmography, transfer factors for CO and NO (TLCO, TLNO), bronchial and alveolar NO, cytokines in serum and nasal secretions (IL-1β, IL-5, IL-6, IL-8, GM-CSF, IFNγ, TNFα), serum ECP, and IgE. Across all participants, no statistically significant changes occurred for lung mechanics and NO. There was a decrease in volume-related TLNO that was more pronounced in HLE, but the difference to LLE was not significant. ECP and IgE increased in the same way after exposures. Nasal IL-6 showed a higher increase after LLE. There was no coherent pattern regarding the responses in the participant subgroups or single sets of variables. In conclusion, the experimental acute responses to short but very high-level LPD exposures were small and did not indicate clinically relevant effects compared to low particle number concentrations. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  20. Youth exposure to in-vehicle second-hand smoke and their smoking behaviours: trends and associations in repeated national surveys (2006-2012).

    Science.gov (United States)

    Healey, Benjamin; Hoek, Janet; Wilson, Nick; Thomson, George; Taylor, Steve; Edwards, Richard

    2015-03-01

    To extend the limited international evidence on youth in-vehicle second-hand smoke (SHS) exposure by examining trends in New Zealand, a country with a national smoke-free goal and indoors smoke-free environment legislation. We tracked exposure rates and explored the associations between in-vehicle SHS exposure and smoking behaviours. In-home exposure was also examined for comparative purposes. Data were collected in annual surveys of over 25 000 year 10 school students (14-15-year olds) for a 7-year period (2006-2012). Questions covered smoking behaviour, exposure to smoking and demographics. Youth SHS exposure rates in-vehicle and in-home trended down slightly over time (pvehicle in the previous week in 2012. However, marked inequalities in exposure between ethnic groups, and by school-based socioeconomic position, persisted. The strongest association with SHS exposure was parental smoking (eg, for both parents versus neither smoking in 2012: in-vehicle SHS exposure adjusted OR: 7.4; 95% CI: 6.5 to 8.4). After adjusting for seven other factors associated with initiation, logistic regression analyses revealed statistically significant associations of in-vehicle SHS exposure with susceptibility to initiation and smoking. The slow decline in SHS exposure in vehicles and the lack of progress in reducing relative inequalities is problematic. To accelerate progress, the New Zealand Government could follow the example of other jurisdictions and prohibit smoking in cars carrying children. Other major policy interventions, beside enhanced smoke-free environments, will also likely be required if New Zealand is to achieve its 2025 smoke-free nation goal. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  1. Repeat exposure to ciguatoxin leads to enhanced and sustained thermoregulatory, pain threshold and motor activity responses in mice: relationship to blood ciguatoxin concentrations.

    Science.gov (United States)

    Bottein Dechraoui, Marie-Yasmine; Rezvani, Amir H; Gordon, Christopher J; Levin, Edward D; Ramsdell, John S

    2008-04-03

    Ciguatera is a common illness in tropical and subtropical regions that manifests in complex and long-lived symptoms which are more severe in subsequent exposures. This study measures central and peripheral neurologic signs, in parallel with blood toxin levels, in mice exposed once or twice (at 3 days interval) to a sublethal dose of ciguatoxin P-CTX-1 (0.26ng/g via i.p.). Mice were implanted with radiotransmitters to monitor motor activity and core temperature. A single exposure to ciguatoxin elicited an immediate and transient decrease in motor activity and temperature, and subsequent long-lasting thermoregulatory dysfunction resulting in stabilized body temperature around 36.0 degrees C with no observable circadian rhythm. The hypothermic response and the reduced activity were enhanced with a second exposure with 30% of the mice dying within 7h. Measurement of the peripheral nervous system by the tail flick assay revealed increased latency with a single ciguatoxin exposure, and a greater effect following the second exposure. Toxin was measurable in blood up to 3 days following the first exposure; at the 1h time point the concentrations were significantly elevated after a second exposure. These findings indicate an early response to ciguatoxin manifest in a central response to lower body temperature and reduce motor activity and a more persistent effect on the peripheral system leading to spinal heat antinociception and delayed fever-like response. The greater neurological response to a second ciguatoxin exposure was associated with elevated concentrations of ciguatoxin in the blood solely over the first hour of exposure. In conclusion, a single exposure to toxin exerts a significant neurological response which may be enhanced with subsequent exposure.

  2. Control of occupational exposure in nuclear facilities for terrestrial support to marine vessels

    International Nuclear Information System (INIS)

    Lara, E.G.; Pinheiro, A.R.M.; Borsoi, S.S.; Silva, T.P.; Baroni, D.B.; Santos, F.C.

    2017-01-01

    This study addresses some basic requirements for exposure control of occupational exposure during the design phase of ground-based nuclear facilities for marine vessels. US regulatory guidelines, CNEN standards and experiences acquired in conventional nuclear installations were used. The installation design should consider the provision of mobile devices for monitoring and decontamination. Finally, it is observed that the establishment of additional exposure control criteria can directly impact the civil, architectural and electromechanical projects of the facility, from the conceptual phase

  3. Repeat polymorphisms in ESR2 and AR and colorectal cancer risk and prognosis: results from a German population-based case-control study.

    Science.gov (United States)

    Rudolph, Anja; Shi, Hong; Försti, Asta; Hoffmeister, Michael; Sainz, Juan; Jansen, Lina; Hemminki, Kari; Brenner, Hermann; Chang-Claude, Jenny

    2014-11-07

    Evidence has accumulated which suggests that sex steroids influence colorectal cancer development and progression. We therefore assessed the association of repeat polymorphisms in the estrogen receptor β gene (ESR2) and the androgen receptor gene (AR) with colorectal cancer risk and prognosis. The ESR2 CA and AR CAG repeat polymorphisms were genotyped in 1798 cases (746 female, 1052 male) and 1810 controls (732 female, 1078 male), matched for sex, age and county of residence. Colorectal cancer risk associations overall and specific for gender were evaluated using multivariate logistic regression models adjusted for sex, county of residence and age. Associations with overall and disease-specific survival were evaluated using Cox proportional hazard models adjusted for established prognostic factors (diagnosis of other cancer after colorectal cancer diagnosis, detection by screening, treatment with adjuvant chemotherapy, tumour extent, nodal status, distant metastasis, body mass index, age at diagnosis and year of diagnosis) and stratified for grade of differentiation. Heterogeneity in gender specific associations was assessed by comparing models with and without a multiplicative interaction term by means of a likelihood ratio test. The average number of ESR2 CA repeats was associated with a small 5% increase in colorectal cancer risk (OR = 1.05, 95% CI 1.01-1.10) without significant heterogeneity according to gender or tumoural ESR2 expression. We found no indication for an association between the AR CAG repeat polymorphisms and risk of colorectal cancer. The ESR2 CA and AR CAG repeat polymorphisms were not associated with overall survival or disease specific survival after colorectal cancer diagnosis. Higher numbers of ESR2 CA repeats are potentially associated with a small increase in colorectal cancer risk. Our study does not support an association between colorectal cancer prognosis and the investigated repeat polymorphisms.

  4. Genetic susceptibility loci, environmental exposures, and Parkinson's disease: a case-control study of gene-environment interactions.

    Science.gov (United States)

    Chung, Sun Ju; Armasu, Sebastian M; Anderson, Kari J; Biernacka, Joanna M; Lesnick, Timothy G; Rider, David N; Cunningham, Julie M; Ahlskog, J Eric; Frigerio, Roberta; Maraganore, Demetrius M

    2013-06-01

    Prior studies causally linked mutations in SNCA, MAPT, and LRRK2 genes with familial Parkinsonism. Genome-wide association studies have demonstrated association of single nucleotide polymorphisms (SNPs) in those three genes with sporadic Parkinson's disease (PD) susceptibility worldwide. Here we investigated the interactions between SNPs in those three susceptibility genes and environmental exposures (pesticides application, tobacco smoking, coffee drinking, and alcohol drinking) also associated with PD susceptibility. Pairwise interactions between environmental exposures and 18 variants (16 SNPs and two variable number tandem repeats, or "VNTRs") in SNCA, MAPT and LRRK2, were investigated using data from 1098 PD cases from the upper Midwest, USA and 1098 matched controls. Environmental exposures were assessed using a validated telephone interview script. Five pairwise interactions had uncorrected P-values coffee drinking × MAPT H1/H2 haplotype or MAPT rs16940806, and alcohol drinking × MAPT rs2435211. None of these interactions remained significant after Bonferroni correction. Secondary analyses in strata defined by type of control (sibling or unrelated), sex, or age at onset of the case also did not identify significant interactions after Bonferroni correction. This study documented limited pairwise interactions between established genetic and environmental risk factors for PD; however, the associations were not significant after correction for multiple testing. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. Results of verifications of the control automatic exposure in equipment of RX with CR systems

    International Nuclear Information System (INIS)

    Ruiz Manzano, P.; Rivas Ballarin, M. A.; Ortega Pardina, P.; Villa Gazulla, D.; Calvo Carrillo, S.; Canellas Anoz, M.; Millan Cebrian, E.

    2013-01-01

    After the entry into force in 2012, the new Spanish Radiology quality control protocol lists and discusses the results obtained after verification of the automatic control of exposure in computed radiography systems. (Author)

  6. A Comparison of Item Exposure Control Procedures with the Generalized Partial Credit Model

    Science.gov (United States)

    Sanchez, Edgar Isaac

    2008-01-01

    To enhance test security of high stakes tests, it is vital to understand the way various exposure control strategies function under various IRT models. To that end the present dissertation focused on the performance of several exposure control strategies under the generalized partial credit model with an item pool of 100 and 200 items. These…

  7. A Comparison of Exposure Control Procedures in CAT Systems Based on Different Measurement Models for Testlets

    Science.gov (United States)

    Boyd, Aimee M.; Dodd, Barbara; Fitzpatrick, Steven

    2013-01-01

    This study compared several exposure control procedures for CAT systems based on the three-parameter logistic testlet response theory model (Wang, Bradlow, & Wainer, 2002) and Masters' (1982) partial credit model when applied to a pool consisting entirely of testlets. The exposure control procedures studied were the modified within 0.10 logits…

  8. Lexical-Semantic Organization in Bilingually Developing Deaf Children with ASL-Dominant Language Exposure: Evidence from a Repeated Meaning Association Task

    Science.gov (United States)

    Mann, Wolfgang; Sheng, Li; Morgan, Gary

    2016-01-01

    This study compared the lexical-semantic organization skills of bilingually developing deaf children in American Sign Language (ASL) and English with those of a monolingual hearing group. A repeated meaning-association paradigm was used to assess retrieval of semantic relations in deaf 6-10-year-olds exposed to ASL from birth by their deaf…

  9. A four-year field program investigating long-term effects of repeated exposure of honey bee colonies to flowering crops treated with thiamethoxam.

    Directory of Open Access Journals (Sweden)

    Edward Pilling

    Full Text Available Neonicotinoid residues in nectar and pollen from crop plants have been implicated as one of the potential factors causing the declines of honey bee populations. Median residues of thiamethoxam in pollen collected from honey bees after foraging on flowering seed treated maize were found to be between 1 and 7 µg/kg, median residues of the metabolite CGA322704 (clothianidin in the pollen were between 1 and 4 µg/kg. In oilseed rape, median residues of thiamethoxam found in pollen collected from bees were between <1 and 3.5 µg/kg and in nectar from foraging bees were between 0.65 and 2.4 µg/kg. Median residues of CGA322704 in pollen and nectar in the oilseed rape trials were all below the limit of quantification (1 µg/kg. Residues in the hive were even lower in both the maize and oilseed rape trials, being at or below the level of detection of 1 µg/kg for bee bread in the hive and at or below the level of detection of 0.5 µg/kg for hive nectar, honey and royal jelly samples. The long-term risk to honey bee colonies in the field was also investigated, including the sensitive overwintering stage, from four years consecutive single treatment crop exposures to flowering maize and oilseed rape grown from thiamethoxam treated seeds at rates recommended for insect control. Throughout the study, mortality, foraging behavior, colony strength, colony weight, brood development and food storage levels were similar between treatment and control colonies. Detailed examination of brood development throughout the year demonstrated that colonies exposed to the treated crop were able to successfully overwinter and had a similar health status to the control colonies in the following spring. We conclude that these data demonstrate there is a low risk to honey bees from systemic residues in nectar and pollen following the use of thiamethoxam as a seed treatment on oilseed rape and maize.

  10. A Four-Year Field Program Investigating Long-Term Effects of Repeated Exposure of Honey Bee Colonies to Flowering Crops Treated with Thiamethoxam

    Science.gov (United States)

    Pilling, Edward; Campbell, Peter; Coulson, Mike; Ruddle, Natalie; Tornier, Ingo

    2013-01-01

    Neonicotinoid residues in nectar and pollen from crop plants have been implicated as one of the potential factors causing the declines of honey bee populations. Median residues of thiamethoxam in pollen collected from honey bees after foraging on flowering seed treated maize were found to be between 1 and 7 µg/kg, median residues of the metabolite CGA322704 (clothianidin) in the pollen were between 1 and 4 µg/kg. In oilseed rape, median residues of thiamethoxam found in pollen collected from bees were between <1 and 3.5 µg/kg and in nectar from foraging bees were between 0.65 and 2.4 µg/kg. Median residues of CGA322704 in pollen and nectar in the oilseed rape trials were all below the limit of quantification (1 µg/kg). Residues in the hive were even lower in both the maize and oilseed rape trials, being at or below the level of detection of 1 µg/kg for bee bread in the hive and at or below the level of detection of 0.5 µg/kg for hive nectar, honey and royal jelly samples. The long-term risk to honey bee colonies in the field was also investigated, including the sensitive overwintering stage, from four years consecutive single treatment crop exposures to flowering maize and oilseed rape grown from thiamethoxam treated seeds at rates recommended for insect control. Throughout the study, mortality, foraging behavior, colony strength, colony weight, brood development and food storage levels were similar between treatment and control colonies. Detailed examination of brood development throughout the year demonstrated that colonies exposed to the treated crop were able to successfully overwinter and had a similar health status to the control colonies in the following spring. We conclude that these data demonstrate there is a low risk to honey bees from systemic residues in nectar and pollen following the use of thiamethoxam as a seed treatment on oilseed rape and maize. PMID:24194871

  11. Exposure to crystalline silica at Alberta work sites: review of controls.

    Science.gov (United States)

    Radnoff, Diane; Todor, Maria S; Beach, Jeremy

    2015-01-01

    From 2009 to 2013, Alberta Jobs, Skills, Training, and Labour (JSTL) conducted a project to evaluate exposure to crystalline silica and assess controls to protect workers. Information on exposure results has been previously reported; this article discusses the data collected on workplace controls. Information on work site controls was collected during exposure assessments consisting of qualitative information on controls in place and used by workers at the time of the assessments. Where there was sufficient data, the information was further analyzed to evaluate the impact of a particular control. While many types of controls were observed, they were not always effective or in use. The control available most often was respiratory protective equipment (RPE). Generally, when respirators were used, they were correctly selected for the level of measured exposure. However, not all workers who were potentially overexposed wore respirators at the time of the assessments. When the use of respirators was taken into account, about one-third of workers were still potentially exposed over the Alberta occupational exposure limit. The industries with the highest levels of exposure tended to be those with the most unprotected workers. Issues were identified with the use of improper work practices such as dry cleaning methods, lack of documented work procedures, poor housekeeping, and lack of training which may have contributed to worker exposure levels. There is a wide range in the efficacy of controls, particularly engineering controls. Most of the literature focuses on engineering controls; however administrative controls also play a role in reducing worker exposure. Data collected in this work indicated that simple changes to work procedures and behavior (such as improved housekeeping) may be effective, low-cost ways to reduce workplace exposure. More study is required to evaluate the impact and efficacy of administrative controls such as housekeeping and training. Employers

  12. Tuning of automatic exposure control strength in lumbar spine CT.

    Science.gov (United States)

    D'Hondt, A; Cornil, A; Bohy, P; De Maertelaer, V; Gevenois, P A; Tack, D

    2014-05-01

    To investigate the impact of tuning the automatic exposure control (AEC) strength curve (specific to Care Dose 4D®; Siemens Healthcare, Forchheim, Germany) from "average" to "strong" on image quality, radiation dose and operator dependency during lumbar spine CT examinations. Two hospitals (H1, H2), both using the same scanners, were considered for two time periods (P1 and P2). During P1, the AEC curve was "average" and radiographers had to select one of two protocols according to the body mass index (BMI): "standard" if BMI 30.0 kg m(-2) (140 kV-280 mAs). During P2, the AEC curve was changed to "strong", and all acquisitions were obtained with one protocol (120 kV and 270 mAs). Image quality was scored and patients' diameters calculated for both periods. 497 examinations were analysed. There was no significant difference in mean diameters according to hospitals and periods (p > 0.801) and in quality scores between periods (p > 0.172). There was a significant difference between hospitals regarding how often the "large" protocol was assigned [13 (10%)/132 patients in H1 vs 37 (28%)/133 in H2] (p < 0.001). During P1, volume CT dose index (CTDIvol) was higher in H2 (+13%; p = 0.050). In both hospitals, CTDIvol was reduced between periods (-19.2% in H1 and -29.4% in H2; p < 0.001). An operator dependency in protocol selection, unexplained by patient diameters or highlighted by image quality scores, has been observed. Tuning the AEC curve from average to strong enables suppression of the operator dependency in protocol selection and related dose increase, while preserving image quality. CT acquisition protocols based on weight are responsible for biases in protocol selection. Using an appropriate AEC strength curve reduces the number of protocols to one. Operator dependency of protocol selection is thereby eliminated.

  13. CONTROLLED EXPOSURES OF HUMAN VOLUNTEERS TO DIESEL ENGINE EXHAUST: BIOMARKERS OF EXPOSURE AND HEALTH OUTCOMES

    Science.gov (United States)

    Combustion of diesel fuel contributes to ambient air pollutant fine particulate matter (PM) and gases. Fine PM exposure has been associated with increased mortality due to adverse cardiac events, and morbidity, such as increased hospitalization for asthma symptoms and lung infect...

  14. Controlling occupational radiation exposure at operating nuclear power stations

    International Nuclear Information System (INIS)

    Dickson, H.W.; Oakes, T.W.; Shank, K.E.

    1977-01-01

    The historical development of the philosophy of keeping the radiation exposure of workers at light-water reactors as low as reasonably achievable (ALARA) is presented. A review is made of some of the ALARA activities of the Nuclear Regulatory Commission, the Energy Research and Development Administration, and various nuclear installations. Data compiled by the NRC show that routine and special maintenance at light-water reactors accounts for 72 percent of all occupational exposure at these sites. The role that Oak Ridge National Laboratory has taken in ALARA research is presented, with emphasis placed on a study of valve malfunctions at light-water reactors. The valve study indicates a trend toward decreasing valve reliability over the past few years. Finally a cost--benefit analysis of radiation dose reduction is discussed. The rationale for assigning a cost per man-rem based on the radiation exposure level that is encountered is presented

  15. Occupational Exposure Assessment of Nanomaterials using Control Banding Tools

    DEFF Research Database (Denmark)

    Liguori, Biase

    , are relatively advanced, and they are good foundations for an advanced exposure assessment. Considering the tiered approach for workplace assessment proposed by the OECD, these two tools could be situated, between Tier 1 (Information gathering) and Tier 2 (Basic exposure assessment). Moreover, the thesis......Nanotechnology can be termed as the “new industrial revolution”. A broad range of potential benefits in various applications for the environment and everyday life of humans can be related to the use of nanotechnology. Nanomaterials are used in a large variety of products already in the market......, and because of their novel physical and chemical characteristics, the application of nanomaterials is projected to increase further. This will inevitably increase the production of nanomaterials with potential increase of exposure for the workers which are the first in line expected to become exposed...

  16. Effect of restrictions on television food advertising to children on exposure to advertisements for 'less healthy' foods: repeat cross-sectional study.

    Directory of Open Access Journals (Sweden)

    Jean Adams

    Full Text Available In 2007, new scheduling restrictions on television food advertising to children in the UK were announced. The aim of the restrictions was to "reduce significantly the exposure of children under 16 to high fat, salt or sugar (HFSS advertising". We explored the impact of the restrictions on relative exposure to HFSS food advertising among all viewers and among child television viewers, as well as adherence to the restrictions.We conducted two cross-sectional studies of all advertisements broadcast in one region of the UK over one week periods--the first (week 1 six months before the restrictions were introduced, and the second (week 2 six months after. Data on what products were advertised were linked to data on how many people watched each advertisement. Nutritional content of foods advertised was added to the dataset and used to calculate HFSS status. Relative exposure was calculated as the proportion of all advertising person-minute-views (PMVs that were for HFSS foods.1,672,417 advertising PMV were included. 14.6% of advertising PMV were for food and 51.1% of these were for HFSS food. Relative exposure of all viewers to HFSS food advertising increased between study weeks 1 and 2 (odds ratio (99% confidence intervals = 1·54 (1·51 to 1·57. Exposure of children to HFSS food advertising did not change between study weeks 1 and 2 (odds ratio (99% confidence intervals = 1·05 (0·99 to 1·12. There was almost universal adherence to the restrictions.Despite good adherence to the restrictions, they did not change relative exposure of children to HFSS advertising and were associated with an increase in relative exposure of all viewers to HFSS advertising. Stronger restrictions targeting a wider range of advertisements are necessary to reduce exposure of children to marketing of less healthful foods.

  17. Effect of restrictions on television food advertising to children on exposure to advertisements for 'less healthy' foods: repeat cross-sectional study.

    Science.gov (United States)

    Adams, Jean; Tyrrell, Rachel; Adamson, Ashley J; White, Martin

    2012-01-01

    In 2007, new scheduling restrictions on television food advertising to children in the UK were announced. The aim of the restrictions was to "reduce significantly the exposure of children under 16 to high fat, salt or sugar (HFSS) advertising". We explored the impact of the restrictions on relative exposure to HFSS food advertising among all viewers and among child television viewers, as well as adherence to the restrictions. We conducted two cross-sectional studies of all advertisements broadcast in one region of the UK over one week periods--the first (week 1) six months before the restrictions were introduced, and the second (week 2) six months after. Data on what products were advertised were linked to data on how many people watched each advertisement. Nutritional content of foods advertised was added to the dataset and used to calculate HFSS status. Relative exposure was calculated as the proportion of all advertising person-minute-views (PMVs) that were for HFSS foods. 1,672,417 advertising PMV were included. 14.6% of advertising PMV were for food and 51.1% of these were for HFSS food. Relative exposure of all viewers to HFSS food advertising increased between study weeks 1 and 2 (odds ratio (99% confidence intervals) = 1·54 (1·51 to 1·57)). Exposure of children to HFSS food advertising did not change between study weeks 1 and 2 (odds ratio (99% confidence intervals) = 1·05 (0·99 to 1·12)). There was almost universal adherence to the restrictions. Despite good adherence to the restrictions, they did not change relative exposure of children to HFSS advertising and were associated with an increase in relative exposure of all viewers to HFSS advertising. Stronger restrictions targeting a wider range of advertisements are necessary to reduce exposure of children to marketing of less healthful foods.

  18. Effect of Restrictions on Television Food Advertising to Children on Exposure to Advertisements for ‘Less Healthy’ Foods: Repeat Cross-Sectional Study

    Science.gov (United States)

    Adams, Jean; Tyrrell, Rachel; Adamson, Ashley J.; White, Martin

    2012-01-01

    Background In 2007, new scheduling restrictions on television food advertising to children in the UK were announced. The aim of the restrictions was to “reduce significantly the exposure of children under 16 to high fat, salt or sugar (HFSS) advertising”. We explored the impact of the restrictions on relative exposure to HFSS food advertising among all viewers and among child television viewers, as well as adherence to the restrictions. Methods We conducted two cross-sectional studies of all advertisements broadcast in one region of the UK over one week periods – the first (week 1) six months before the restrictions were introduced, and the second (week 2) six months after. Data on what products were advertised were linked to data on how many people watched each advertisement. Nutritional content of foods advertised was added to the dataset and used to calculate HFSS status. Relative exposure was calculated as the proportion of all advertising person-minute-views (PMVs) that were for HFSS foods. Results 1,672,417 advertising PMV were included. 14.6% of advertising PMV were for food and 51.1% of these were for HFSS food. Relative exposure of all viewers to HFSS food advertising increased between study weeks 1 and 2 (odds ratio (99% confidence intervals) = 1·54 (1·51 to 1·57)). Exposure of children to HFSS food advertising did not change between study weeks 1 and 2 (odds ratio (99% confidence intervals) = 1·05 (0·99 to 1·12)). There was almost universal adherence to the restrictions. Conclusions Despite good adherence to the restrictions, they did not change relative exposure of children to HFSS advertising and were associated with an increase in relative exposure of all viewers to HFSS advertising. Stronger restrictions targeting a wider range of advertisements are necessary to reduce exposure of children to marketing of less healthful foods. PMID:22355376

  19. Exposure Control Using Adaptive Multi-Stage Item Bundles.

    Science.gov (United States)

    Luecht, Richard M.

    This paper presents a multistage adaptive testing test development paradigm that promises to handle content balancing and other test development needs, psychometric reliability concerns, and item exposure. The bundled multistage adaptive testing (BMAT) framework is a modification of the computer-adaptive sequential testing framework introduced by…

  20. Repeated intermittent alcohol exposure during the third trimester-equivalent increases expression of the GABA(A) receptor δ subunit in cerebellar granule neurons and delays motor development in rats.

    Science.gov (United States)

    Diaz, Marvin R; Vollmer, Cyndel C; Zamudio-Bulcock, Paula A; Vollmer, William; Blomquist, Samantha L; Morton, Russell A; Everett, Julie C; Zurek, Agnieszka A; Yu, Jieying; Orser, Beverley A; Valenzuela, C Fernando

    2014-04-01

    Exposure to ethanol (EtOH) during fetal development can lead to long-lasting alterations, including deficits in fine motor skills and motor learning. Studies suggest that these are, in part, a consequence of cerebellar damage. Cerebellar granule neurons (CGNs) are the gateway of information into the cerebellar cortex. Functionally, CGNs are heavily regulated by phasic and tonic GABAergic inhibition from Golgi cell interneurons; however, the effect of EtOH exposure on the development of GABAergic transmission in immature CGNs has not been investigated. To model EtOH exposure during the 3rd trimester-equivalent of human pregnancy, neonatal pups were exposed intermittently to high levels of vaporized EtOH from postnatal day (P) 2 to P12. This exposure gradually increased pup serum EtOH concentrations (SECs) to ∼60 mM (∼0.28 g/dl) during the 4 h of exposure. EtOH levels gradually decreased to baseline 8 h after the end of exposure. Surprisingly, basal tonic and phasic GABAergic currents in CGNs were not significantly affected by postnatal alcohol exposure (PAE). However, PAE increased δ subunit expression at P28 as detected by immunohistochemical and western blot analyses. Also, electrophysiological studies with an agonist that is highly selective for δ-containing GABA(A) receptors, 4,5,6,7-tetrahydroisoxazolo[4,5-c]pyridine-3-ol (THIP), showed an increase in THIP-induced tonic current. Behavioral studies of PAE rats did not reveal any deficits in motor coordination, except for a delay in the acquisition of the mid-air righting reflex that was apparent at P15 to P18. These findings demonstrate that repeated intermittent exposure to high levels of EtOH during the equivalent of the last trimester of human pregnancy has significant but relatively subtle effects on motor coordination and GABAergic transmission in CGNs in rats. Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. The effects of a single whole body cryotherapy exposure on physiological, performance and perceptual responses of professional academy soccer players following repeated sprint exercise

    OpenAIRE

    Russell, Mark; Birch, Jack; Love, Thomas; Cook, Christian; Bracken, Richard M.; Taylor, Tom; Swift, Eamon; Cockburn, Emma; Finn, Charlie; Cunningham, Daniel; Wilson, Laura; Kilduff, Liam P.

    2017-01-01

    In professional youth soccer players, the physiological, performance and perceptual effects of a single whole body cryotherapy (WBC) session performed shortly after repeated sprint exercise were investigated. In a randomized, counter-balanced and crossover design, 14 habituated English Premier League academy soccer players performed 15 x 30 m sprints (each followed by a 10 m forced deceleration) on two occasions. Within 20 min of exercise cessation, players entered a WBC chamber (Cryo: 30 s a...

  2. Changes in child exposure to secondhand smoke after implementation of smoke-free legislation in Wales: a repeated cross-sectional study

    Directory of Open Access Journals (Sweden)

    Holliday Jo

    2009-01-01

    Full Text Available Abstract Background Smoke-free legislation was introduced in Wales in April 2007. In response to concerns regarding potential displacement of smoking into the home following legislation, this study assessed changes in secondhand smoke (SHS exposure amongst non-smoking children. Methods Approximately 1,750 year 6 (aged 10-11 children from 75 Welsh primary schools were included in cross-sectional surveys immediately pre-legislation and one year later. Participants completed self-report questionnaires and provided saliva samples for cotinine assay. Regression analyses assessed the impact of legislation on children's SHS exposure at the population level, and amongst subgroups defined by parental figures who smoke within the home. Results Geometric mean salivary cotinine concentrations were 0.17 ng/ml (95% CI 0.15,0.20 pre-legislation and 0.15 ng/ml (95% CI 0.13,0.17, post-legislation, although this change was not statistically significant. Significant movement was however observed from the middle (0.10-0.50 ng/ml to lower tertile, though not from the higher end (>0.51 ng/ml to the middle. Reported exposure to SHS was greatest within the home. Home-based exposure did not change significantly post-legislation. Reported exposure in cafés or restaurants, buses and trains, and indoor leisure facilities fell significantly. The proportion of children reporting that parent figures smoked in the home declined (P = 0.03, with children with no parent figures who smoke in the home significantly more likely to provide saliva with cotinine concentrations of <0.10 ng/ml post-legislation. Amongst children with no parent figures who smoke in the home, the likelihood of 'not knowing' or 'never' being in a place where people were smoking increased post-legislation. Conclusion Smoke-free legislation in Wales did not increase SHS exposure in homes of children aged 10-11. Reported SHS exposure in public places fell significantly. The home remained the main source of

  3. Tailoring automatic exposure control toward constant detectability in digital mammography.

    Science.gov (United States)

    Salvagnini, Elena; Bosmans, Hilde; Struelens, Lara; Marshall, Nicholas W

    2015-07-01

    The automatic exposure control (AEC) modes of most full field digital mammography (FFDM) systems are set up to hold pixel value (PV) constant as breast thickness changes. This paper proposes an alternative AEC mode, set up to maintain some minimum detectability level, with the ultimate goal of improving object detectability at larger breast thicknesses. The default "opdose" AEC mode of a Siemens MAMMOMAT Inspiration FFDM system was assessed using poly(methyl methacrylate) (PMMA) of thickness 20, 30, 40, 50, 60, and 70 mm to find the tube voltage and anode/filter combination programmed for each thickness; these beam quality settings were used for the modified AEC mode. Detectability index (d'), in terms of a non-prewhitened model observer with eye filter, was then calculated as a function of tube current-time product (mAs) for each thickness. A modified AEC could then be designed in which detectability never fell below some minimum setting for any thickness in the operating range. In this study, the value was chosen such that the system met the achievable threshold gold thickness (Tt) in the European guidelines for the 0.1 mm diameter disc (i.e., Tt ≤ 1.10 μm gold). The default and modified AEC modes were compared in terms of contrast-detail performance (Tt), calculated detectability (d'), signal-difference-to-noise ratio (SDNR), and mean glandular dose (MGD). The influence of a structured background on object detectability for both AEC modes was examined using a CIRS BR3D phantom. Computer-based CDMAM reading was used for the homogeneous case, while the images with the BR3D background were scored by human observers. The default opdose AEC mode maintained PV constant as PMMA thickness increased, leading to a reduction in SDNR for the homogeneous background 39% and d' 37% in going from 20 to 70 mm; introduction of the structured BR3D plate changed these figures to 22% (SDNR) and 6% (d'), respectively. Threshold gold thickness (0.1 mm diameter disc) for the default

  4. Tailoring automatic exposure control toward constant detectability in digital mammography

    Energy Technology Data Exchange (ETDEWEB)

    Salvagnini, Elena, E-mail: elena.salvagnini@uzleuven.be [Department of Imaging and Pathology, Medical Physics and Quality Assessment, KUL, Herestraat 49, Leuven B-3000, Belgium and SCK-CEN, Boeretang 200, Mol 2400 (Belgium); Bosmans, Hilde [Department of Imaging and Pathology, Medical Physics and Quality Assessment, KUL, Herestraat 49, Leuven B-3000, Belgium and Department of Radiology, UZ Gasthuisberg, Herestraat 49, Leuven B-3000 (Belgium); Struelens, Lara [SCK-CEN, Boeretang 200, Mol 2400 (Belgium); Marshall, Nicholas W. [Department of Radiology, UZ Gasthuisberg, Herestraat 49, Leuven B-3000 (Belgium)

    2015-07-15

    Purpose: The automatic exposure control (AEC) modes of most full field digital mammography (FFDM) systems are set up to hold pixel value (PV) constant as breast thickness changes. This paper proposes an alternative AEC mode, set up to maintain some minimum detectability level, with the ultimate goal of improving object detectability at larger breast thicknesses. Methods: The default “OPDOSE” AEC mode of a Siemens MAMMOMAT Inspiration FFDM system was assessed using poly(methyl methacrylate) (PMMA) of thickness 20, 30, 40, 50, 60, and 70 mm to find the tube voltage and anode/filter combination programmed for each thickness; these beam quality settings were used for the modified AEC mode. Detectability index (d′), in terms of a non-prewhitened model observer with eye filter, was then calculated as a function of tube current-time product (mAs) for each thickness. A modified AEC could then be designed in which detectability never fell below some minimum setting for any thickness in the operating range. In this study, the value was chosen such that the system met the achievable threshold gold thickness (T{sub t}) in the European guidelines for the 0.1 mm diameter disc (i.e., T{sub t} ≤ 1.10 μm gold). The default and modified AEC modes were compared in terms of contrast-detail performance (T{sub t}), calculated detectability (d′), signal-difference-to-noise ratio (SDNR), and mean glandular dose (MGD). The influence of a structured background on object detectability for both AEC modes was examined using a CIRS BR3D phantom. Computer-based CDMAM reading was used for the homogeneous case, while the images with the BR3D background were scored by human observers. Results: The default OPDOSE AEC mode maintained PV constant as PMMA thickness increased, leading to a reduction in SDNR for the homogeneous background 39% and d′ 37% in going from 20 to 70 mm; introduction of the structured BR3D plate changed these figures to 22% (SDNR) and 6% (d′), respectively

  5. Exposure of eyes to perfume: a double-blind, placebo-controlled experiment.

    Science.gov (United States)

    Elberling, J; Duus Johansen, J; Dirksen, A; Mosbech, H

    2006-08-01

    Environmental perfume exposure can elicit bothersome respiratory symptoms. Symptoms are induced at exposure levels which most people find tolerable, and the mechanisms are unclear. The aim of the study was to investigate patients with eye and respiratory symptoms related to environmental perfume, by exposing the eyes to perfume in a double-blind, placebo-controlled study.Twenty-one eczema patients with respiratory symptoms elicited by perfume were compared with 21 healthy volunteers in a sex- and age-matched case-control study. The participants completed a symptom questionnaire, and underwent a double-blind, placebo-controlled exposure to perfume. Of the 42 individuals tested, 10 had more eye symptoms (irritation, itching, and tears) during perfume exposure than during placebo exposures, and eight of these individuals (P = 0.07, Fisher's exact test) belonged to the patient group. A true positive eye reaction to perfume was significantly associated with identification of perfume as an active exposure (P perfume elicited irritation in the eyes independently of olfaction, but the relative importance of ocular chemoperception in relation to elicitation of respiratory symptoms from common environmental exposures to perfume remains unclear. We investigated the hypothesis of an association between respiratory symptoms related to perfume and ocular perfume sensitivity by exposing the eyes to perfume in a double blind, placebo-controlled experiment. Vapors of perfume provoked symptoms in the relevant eye in some patients and healthy control persons, but under our exposure conditions, ocular chemesthesis failed to elicit respiratory symptoms.

  6. Controlled human exposure to indoor air, dust, and ozone; XDOZ

    DEFF Research Database (Denmark)

    Elholm, Grethe; Bønløkke, Jakob; Schlünssen, Vivi

    2017-01-01

    . All participants were subjected to four different exposure scenarios in the climate chamber.Exp. 1: Dust (250 – 300 µg/m3)Exp. 2: Ozone (100 ppb)Exp. 3: Dust (250 – 300 µg/m3) + ozone (100 ppb)Exp. 4: Filtered air (<20µg/m3)The exposure time was 5½ hours for each session.The health effects were...... evaluated at baseline and specific follow-up times in relation to selected respiratory and cardiovascular outcomes, such as; nasal volume, exhaled nitric oxide (FENO), spirometry (FEV1 and FVC), exhaled breath condensate (EBC), nasal lavage, blood samples, EndoPat. Questionnaires were used for assessment...

  7. The control and monitoring of exposures at AWRE

    International Nuclear Information System (INIS)

    Jones, E.W.; Taylor, N.A.; Woodville, A.C.

    1987-01-01

    If attempts are to be made to learn about the health effects of low doses of radiation by epidemiological study of ''radiation workers'' it is desirable to understand something of such a population, the conditions under which occupational exposures occur, the statistical distribution of doses and the quality of the recorded dosimetric data. These points are illustrated by reference to the monitored workers at a large nuclear establishment with particular examples from plutonium work. (author)

  8. Acute effects of acrolein in human volunteers during controlled exposure.

    Science.gov (United States)

    Dwivedi, Aishwarya M; Johanson, Gunnar; Lorentzen, Johnny C; Palmberg, Lena; Sjögren, Bengt; Ernstgård, Lena

    2015-01-01

    Acrolein is a reactive aldehyde mainly formed by combustion. The critical effect is considered to be irritation of the eyes and airways; however, the scarce data available make it difficult to assess effect levels. The aim of the study was to determine thresholds for acute irritation for acrolein. Nine healthy volunteers of each sex were exposed at six occasions for 2 h at rest to: clean air, 15 ppm ethyl acetate (EA), and 0.05 ppm and 0.1 ppm acrolein with and without EA (15 ppm) to mask the potential influence of odor. Symptoms related to irritation and central nervous system effects were rated on 100-mm Visual Analogue Scales. The ratings of eye irritation were slightly but significantly increased during exposure to acrolein in a dose-dependent manner (p acrolein alone but not during any of the other five exposure conditions. Based on subjective ratings, the present study showed minor eye irritation by exposure to 0.1 ppm acrolein.

  9. Dose-Response for Multiple Biomarkers of Exposure and Genotoxic Effect Following Repeated Treatment of Rats with the Alkylating Agents, MMS and MNU.

    Science.gov (United States)

    Ji, Zhiying; LeBaron, Matthew J; Schisler, Melissa R; Zhang, Fagen; Bartels, Michael J; Gollapudi, B Bhaskar; Pottenger, Lynn H

    2016-05-01

    The nature of the dose-response relationship for various in vivo endpoints of exposure and effect were investigated using the alkylating agents, methyl methanesulfonate (MMS) and methylnitrosourea (MNU). Six male F344 rats/group were dosed orally with 0, 0.5, 1, 5, 25 or 50mg/kg bw/day (mkd) of MMS, or 0, 0.01, 0.1, 1, 5, 10, 25 or 50 mkd of MNU, for 4 consecutive days and sacrificed 24h after the last dose. The dose-responses for multiple biomarkers of exposure and genotoxic effect were investigated. In MMS-treated rats, the hemoglobin adduct level, a systemic exposure biomarker, increased linearly with dose (r (2) = 0.9990, P agents. © The Author 2015. Published by Oxford University Press on behalf of the UK Environmental Mutagen Society. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  10. Rationale and design of REACT: a randomised controlled trial assessing the effectiveness of home-collection to increase chlamydia retesting and detect repeat positive tests

    OpenAIRE

    Smith, Kirsty S; Hocking, Jane S; Chen, Marcus; Fairley, Christopher K; McNulty, Anna; Read, Phillip; Bradshaw, Catriona S; Tabrizi, Sepehr N; Wand, Handan; Saville, Marion; Rawlinson, William; Garland, Suzanne M; Donovan, Basil; Kaldor, John M; Guy, Rebecca

    2014-01-01

    Background Repeat infection with Chlamydia trachomatis is common and increases the risk of sequelae in women and HIV seroconversion in men who have sex with men (MSM). Despite guidelines recommending chlamydia retesting three months after treatment, retesting rates are low. We are conducting the first randomised controlled trial to assess the effectiveness of home collection combined with short message service (SMS) reminders on chlamydia retesting and reinfection rates in three risk groups. ...

  11. Association of STin2 Variable Number of Tandem Repeat (VNTR) Polymorphism of Serotonin Transporter Gene with Lifelong Premature Ejaculation: A Case-Control Study in Han Chinese Subjects

    Science.gov (United States)

    Huang, Yuanyuan; Zhang, Xiansheng; Gao, Jingjing; Tang, Dongdong; Gao, Pan; Peng, Dangwei; Liang, Chaozhao

    2016-01-01

    Background The STin2 VNTR polymorphism has a variable number of tandem repeats in intron 2 of the serotonin transporter gene. We aimed to explore the relationship between STin2 VNTR polymorphism and lifelong premature ejaculation (LPE). Material/Methods We recruited a total of 115 outpatients who complained of ejaculating prematurely and who were diagnosed as LPE, and 101 controls without PE complaint. Allelic variations of STin2 VNTR were genotyped using PCR-based technology. We evaluated the associations between STin2 VNTR allelic and genotypic frequencies and LPE, as well as the intravaginal ejaculation latency time (IELT) of different STin2 VNTR genotypes among LPE patients. Results The patients and controls did not differ significantly in terms of any characteristic except age. A significantly higher frequency of STin2.12/12 genotype was found among LPE patients versus controls (P=0.026). Frequency of patients carrying at least 1 copy of the 10-repeat allele was significantly lower compared to the control group (28.3% vs. 41.8%, OR=0.55; 95%CI=0.31–0.97, P=0.040). In the LPE group, the mean IELT showed significant difference in STin2.12/12 genotype when compared to those with STin2.12/10 and STin2.10/10 genotypes. The mean IELT in10-repeat allele carriers was 50% longer compared to homozygous carriers of the STin2.12 allele. Conclusions Our results indicate the presence of STin2.10 allele is a protective factor for LPE. Men carrying the higher expression genotype STin2. 12/12 have shorter IELT than 10-repeat allele carriers. PMID:27713390

  12. Electronic Cigarette Exposure: Calls to Wisconsin Poison Control Centers, 2010–2015.

    Science.gov (United States)

    Weiss, Debora; Tomasallo, Carrie D; Meiman, Jon G; Creswell, Paul D; Melstrom, Paul C; Gummin, David D; Patel, Disa J; Michaud, Nancy T; Sebero, Heather A; Anderson, Henry A

    2016-12-01

    E-cigarettes are battery-powered devices that deliver nicotine and flavorings by aerosol and have been marketed in the United States since 2007. Because e-cigarettes have increased in popularity, toxicity potential from device misuse and malfunction also has increased. National data indicate that during 2010–2014, exposure calls to US poison control centers increased only 0.3% for conventional cigarette exposures, whereas calls increased 41.7% for e-cigarette exposures. We characterized cigarette and e-cigarette exposure calls to the Wisconsin Poison Center January 1, 2010 through October 10, 2015. We compared cigarette and e-cigarette exposure calls by exposure year, demographic characteristics, caller site, exposure site, exposure route, exposure reason, medical outcome, management site, and level of care at a health care facility. During January 2010 to October 2015, a total of 98 e-cigarette exposure calls were reported, and annual exposure calls increased approximately 17-fold, from 2 to 35. During the same period, 671 single-exposure cigarette calls with stable annual call volumes were reported. E-cigarette exposure calls were associated with children aged ≤5 years (57/98, 58.2%) and adults aged ≥20 years (30/98, 30.6%). Cigarette exposure calls predominated among children aged ≤5 years (643/671, 95.8%). The frequency of e-cigarette exposure calls to the Wisconsin Poison Center has increased and is highest among children aged ≤5 years and adults. Strategies are warranted to prevent future poisonings from these devices, including nicotine warning labels and public advisories to keep e-cigarettes away from children.

  13. Repeated short-term stress synergizes the ROS signalling through up regulation of NFkB and iNOS expression induced due to combined exposure of trichloroethylene and UVB rays.

    Science.gov (United States)

    Ali, Farrah; Sultana, Sarwat

    2012-01-01

    Restraint stress is known to catalyse the pathogenesis of the variety of chronic inflammatory disorders. The present study was designed to evaluate the effect of repeated short-term stress (RRS) on cellular transduction apart from oxidative burden and early tumour promotional biomarkers induced due to combined exposure of trichloroethylene (TCE) and Ultra-violet radiation (UVB). RRS leads to the increase in the expression of the stress responsive cellular transduction elements NFkB-p65 and activity of iNOS in the epidermal tissues of mice after toxicant exposure. RRS augments the steep depletion of the cellular antioxidant machinery which was evidenced by the marked depletion in GSH (Glutathione and GSH dependant enzymes), superoxide dismutase and catalase activity that were observed at significance level of P stressed animals and down regulation of DT-diaphorase activity (P short-term stress in the toxic response of TCE and UVB radiation.

  14. A suggested guideline for exposure control from natural radioactivity in future buildings

    International Nuclear Information System (INIS)

    Nambi, K.S.V.; Shukla, V.K.

    1991-01-01

    Naturally occurring radionuclides in building materials are one of the sources of radiation exposure to the population. Their concentrations vary by about 2 to 3 orders of magnitude at different geographical locations. This paper proposes three control methodologies for keeping the population exposure as low as reasonably achievable. Tentative recommendations are also included. (author). 11 refs., 3 tabs., 2 appendixes

  15. Optimization of radiation protection in the control of occupational exposure

    International Nuclear Information System (INIS)

    2002-01-01

    One of the three main principles on which protection against ionizing radiation is based is the principle of the optimization of radiological protection. The principle of the optimization of protection was first enunciated by the International Commission on Radiological Protection in the 1960s. A principal requirement for the optimization of protection and safety has been incorporated into the International Basic Safety Standards for Protection against Ionizing Radiation and for the Safety of Radiation Sources (Basic Safety Standards) from the first edition in 1962 up to the current (1996) edition. The principle of optimization, that all reasonable efforts be made to reduce doses (social and economic factors being taken into account), necessitates considerable effort to apply in practice. The requirement of the Basic Safety Standards to apply the principle of optimization applies to all categories of exposure: occupational, public and medical. The categories of public and medical exposure are rather specific and are covered in other publications; this Safety Report concentrates on the application of the principle to what is probably the largest category, that of occupational exposure. This Safety Report provides practical information on how to apply the optimization of protection in the workplace. The emphasis throughout is on the integration of radiation protection into the more general system of work management, and on the involvement of management and workers in setting up a system of radiation protection and in its implementation. This Safety Report was drafted and finalized in three consultants meetings held in 1999 and 2000. The draft was sent for review and comment to a number of experts, which yielded valuable comments from a number of reviewers whose names are included in the list of contributors to drafting and review

  16. Optimization of radiation protection in the control of occupational exposure

    International Nuclear Information System (INIS)

    2003-01-01

    One of the three main principles on which protection against ionizing radiation is based is the principle of the optimization of radiological protection. The principle of the optimization of protection was first enunciated by the International Commission on Radiological Protection in the 1960s. A principal requirement for the optimization of protection and safety has been incorporated into the International Basic Safety Standards for Protection against Ionizing Radiation and for the Safety of Radiation Sources (Basic Safety Standards) from the first edition in 1962 up to the current (1996) edition. The principle of optimization, that all reasonable efforts be made to reduce doses (social and economic factors being taken into account), necessitates considerable effort to apply in practice. The requirement of the Basic Safety Standards to apply the principle of optimization applies to all categories of exposure: occupational, public and medical. The categories of public and medical exposure are rather specific and are covered in other publications. This Safety Report concentrates on the application of the principle to what is probably the largest category, that of occupational exposure. This Safety Report provides practical information on how to apply the optimization of protection in the workplace. The emphasis throughout is on the integration of radiation protection into the more general system of work management, and on the involvement of management and workers in setting up a system of radiation protection and in its implementation. This Safety Report was drafted and finalized in three consultants meetings held in 1999 and 2000. The draft was sent for review and comment to a number of experts, which yielded valuable comments from a number of reviewers whose names are included in the list of contributors to drafting and review

  17. Optimization of radiation protection in the control of occupational exposure

    International Nuclear Information System (INIS)

    2004-01-01

    One of the three main principles on which protection against ionizing radiation is based is the principle of the optimization of radiological protection. The principle of the optimization of protection was first enunciated by the International Commission on Radiological Protection in the 1960s. A principal requirement for the optimization of protection and safety has been incorporated into the International Basic Safety Standards for Protection against Ionizing Radiation and for the Safety of Radiation Sources (Basic Safety Standards) from the first edition in 1962 up to the current (1996) edition. The principle of optimization, that all reasonable efforts be made to reduce doses (social and economic factors being taken into account), necessitates considerable effort to apply in practice. The requirement of the Basic Safety Standards to apply the principle of optimization applies to all categories of exposure: occupational, public and medical. The categories of public and medical exposure are rather specific and are covered in other publications. This Safety Report concentrates on the application of the principle to what is probably the largest category, that of occupational exposure. This Safety Report provides practical information on how to apply the optimization of protection in the workplace. The emphasis throughout is on the integration of radiation protection into the more general system of work management, and on the involvement of management and workers in setting up a system of radiation protection and in its implementation. This Safety Report was drafted and finalized in three consultants meetings held in 1999 and 2000. The draft was sent for review and comment to a number of experts, which yielded valuable comments from a number of reviewers whose names are included in the list of contributors to drafting and review

  18. An evaluation of three simple phantoms used in quality assurance of automatic exposure control

    International Nuclear Information System (INIS)

    Reynolds, S.E.; Rofe, S.

    2000-01-01

    Full text: Different attenuators are used to assess the performance of x-ray systems with automatic exposure control (AEC). Three attenuators, copper, water and hardboard, were compared in this assessment. The Health Physics Service (HPS), which is part of the Department of Medical Physics and Bioengineering at Christchurch Hospital, New Zealand, has chosen to use hardboard as its patient equivalent phantom when testing x-ray equipment simply because it is generally easier to handle compared to water phantoms. Tests were conducted on the hardboard phantom in order to evaluate its effect on radiation in terms of attenuation equivalence, production of scatter and sensitivity to different kilovoltages compared to water or copper. Entrance and exit dose comparison tests were conducted using the AEC on a Philips Optimus 50 x-ray machine. A Keithley Triad Field Service Kit Model 10100A was used to record doses. The first set of tests were designed to ascertain the thickness of water and copper required to produce a similar mAs to the particular thickness of hardboard being examined. The tests were repeated with a film in a cassette which was placed in the bucky tray. Film optical densities were then measured. The hardboard phantom shows a very similar response to radiation as water and hence the human body and is therefore a suitable material for use in the construction of phantoms. Copper produces a very different radiation spectrum and its scattering effects are quite different to water or hardboard. For these reasons we consider copper to be unsuitable for use as a phantom when programming AECs. Copyright (2000) Australasian College of Physical Scientists and Engineers in Medicine

  19. Repeated exposure to corticosterone increases depression-like behavior in two different versions of the forced swim test without altering nonspecific locomotor activity or muscle strength.

    Science.gov (United States)

    Marks, Wendie; Fournier, Neil M; Kalynchuk, Lisa E

    2009-08-04

    We have recently shown that repeated high dose injections of corticosterone (CORT) reliably increase depression-like behavior on a modified one-day version of the forced swim test. The main purpose of this experiment was to compare the effect of these CORT injections on our one-day version of the forced swim test and the more traditional two-day version of the test. A second purpose was to determine whether altered behavior in the forced swim test could be due to nonspecific changes in locomotor activity or muscle strength. Separate groups of rats received a high dose CORT injection (40 mg/kg) or a vehicle injection once per day for 21 consecutive days. Then, half the rats from each group were exposed to the traditional two-day forced swim test and the other half were exposed to our one-day forced swim test. After the forced swim testing, all the rats were tested in an open field and in a wire suspension grip strength test. The CORT injections significantly increased the time spent immobile and decreased the time spent swimming in both versions of the forced swim test. However, they had no significant effect on activity in the open field or grip strength in the wire suspension test. These results show that repeated CORT injections increase depression-like behavior regardless of the specific parameters of forced swim testing, and that these effects are independent of changes in locomotor activity or muscle strength.

  20. Repeated testing improves achievement in a blended learning approach for risk competence training of medical students: results of a randomized controlled trial.

    Science.gov (United States)

    Spreckelsen, C; Juenger, J

    2017-09-26

    Adequate estimation and communication of risks is a critical competence of physicians. Due to an evident lack of these competences, effective training addressing risk competence during medical education is needed. Test-enhanced learning has been shown to produce marked effects on achievements. This study aimed to investigate the effect of repeated tests implemented on top of a blended learning program for risk competence. We introduced a blended-learning curriculum for risk estimation and risk communication based on a set of operationalized learning objectives, which was integrated into a mandatory course "Evidence-based Medicine" for third-year students. A randomized controlled trial addressed the effect of repeated testing on achievement as measured by the students' pre- and post-training score (nine multiple-choice items). Basic numeracy and statistical literacy were assessed at baseline. Analysis relied on descriptive statistics (histograms, box plots, scatter plots, and summary of descriptive measures), bootstrapped confidence intervals, analysis of covariance (ANCOVA), and effect sizes (Cohen's d, r) based on adjusted means and standard deviations. All of the 114 students enrolled in the course consented to take part in the study and were assigned to either the intervention or control group (both: n = 57) by balanced randomization. Five participants dropped out due to non-compliance (control: 4, intervention: 1). Both groups profited considerably from the program in general (Cohen's d for overall pre vs. post scores: 2.61). Repeated testing yielded an additional positive effect: while the covariate (baseline score) exhibits no relation to the post-intervention score, F(1, 106) = 2.88, p > .05, there was a significant effect of the intervention (repeated tests scenario) on learning achievement, F(1106) = 12.72, p blended learning approach can be improved significantly by implementing a test-enhanced learning design, namely repeated testing. As

  1. Effects of prenatal exposure to atypical antipsychotics on postnatal development and growth of infants: a case-controlled, prospective study.

    Science.gov (United States)

    Peng, Mei; Gao, Keming; Ding, Yiling; Ou, Jianjun; Calabrese, Joseph R; Wu, Renrong; Zhao, Jingping

    2013-08-01

    This study aims to investigate the developmental effects of atypical antipsychotics on infants who were born to mothers taking an atypical antipsychotic throughout pregnancy. The developmental progress of 76 infants who experienced fetal exposure to atypical antipsychotics was compared to that of 76 matched control infants who had no fetal exposure to any antipsychotics. Planned assessment included Apgar score, body weight, height, and the cognitive, language, motor, social-emotional, and adaptive behavior composite scores of the Bayley Scales of Infant and Toddler Development, third edition (BSID-III). Student's t test and Chi-square analysis were used as appropriate. Repeated measurements were evaluated by analysis of covariance. At 2 months of age, the mean composite scores of cognitive, motor, social-emotional, and adaptive behavior of BSID-III were significantly lower in atypical antipsychotic-exposed infants than the controls. More atypical antipsychotic-exposed infants had delayed development in cognitive, motor, social-emotional, and adaptive behavior domains as defined by the composite score of development in cognitive, motor, social-emotional, and adaptive behavior, but not in language, body weight, or height.

  2. Repeated Exposure of Epithelial Cells to Apoptotic Cells Induces the Specific Selection of an Adaptive Phenotype: Implications for Tumorigenesis.

    Science.gov (United States)

    Feng, Lanfei; Vujicic, Snezana; Dietrich, Michael E; Litbarg, Natalia; Setty, Suman; Antoni, Angelika; Rauch, Joyce; Levine, Jerrold S

    2018-05-16

    The consequences of apoptosis extend beyond mere death of the cell. We have shown that receptor-mediated recognition of apoptotic target cells by viable kidney proximal tubular epithelial cells (PTECs) inhibits PTEC proliferation, growth, and survival. Here we tested the hypothesis that continual exposure to apoptotic targets can induce a phenotypic change in responding PTECs, as in other instances of natural selection. In particular, we demonstrate that repeated exposure to apoptotic targets leads to emergence of a PTEC line (denoted BU.MPT SEL ) resistant to apoptotic target-induced death. Resistance is exquisitely specific. Not only are BU.MPT SEL responders fully resistant to apoptotic target-induced death (~85% survival versus exposure in selected versus non-selected responders indicated that the acquired resistance of BU.MPT SEL cells lies in a regulatory step affecting the generation of the pro-apoptotic protein, truncated BH3 interacting-domain death agonist (tBID), most likely at the level of BID cleavage by caspase-8. This specific adaptation has especial relevance for cancer, in which the prominence and persistence of cell death entail magnification of the post-mortem effects of apoptotic cells. Just as cancer cells acquire specific resistance to chemotherapeutic agents, we propose that cancer cells may also adapt to their ongoing exposure to apoptotic targets. Published under license by The American Society for Biochemistry and Molecular Biology, Inc.

  3. A case control study of breast cancer risk and exposure to injectable ...

    African Journals Online (AJOL)

    A case control study of breast cancer risk and exposure to injectable progestogen contraceptives. R. Bailie, J Katzenellenbogen, M. Hoffman, G Schierhout, H Truter, D Dent, A Gudgeon, J van Zyl, L Rosenberg, S Shapiro ...

  4. The gene expression and immunohistochemical time-course of diphenylcyclopropenone induced contact allergy in healthy humans following repeated epicutaneous challenges

    DEFF Research Database (Denmark)

    Mose, K F; Burton, M; Thomassen, M

    2017-01-01

    challenges with DPCP to find the predominant gene expression pattern, ii) the time-course of cell infiltration following repeated DPCP challenges, and iii) the transcriptome of a repeated CA exposure model. We obtained punch biopsies from control and DPCP exposed skin from ten DPCP sensitized individuals...

  5. Film repeats in radiology department

    International Nuclear Information System (INIS)

    Suwan, A. Z.; Al-Shakharah, A. I

    1997-01-01

    During a one year period, 4910 radiographs of 55780 films were repeated. The objective of our study was to analyse and to classify the causes in order to minimize the repeats, cut the expenses and to provide optimal radiographs for accurate diagnosis. Analysis of the different factors revealed that, 43.6% of film repeats in our service were due to faults in exposure factors, centering comprises 15.9% of the repeats, while too much collimation was responsible for 7.6% of these repeats. All of which can be decreased by awareness and programmed training of technicians. Film blurring caused by patient motion was also responsible for 4.9% for radiographs reexamination, which can be minimized by detailed explanation to the patient and providing the necessary privacy. Fogging of X-Ray films by improper storage or inadequate handling or processing faults were responsible for 14.5% in repeats in our study. Methods and criteria for proper storage and handling of films were discussed. Recommendation for using modern day-light and laser processor has been high lighted. Artefacts are noticeably high in our cases, due to spinal dresses and frequent usage of precious metals for c osmotic purposes in this part of the world. The repeated films comprise 8.8% of all films We conclude that, the main factor responsible for repeats of up to 81.6% of cases was the technologists, thus emphasizing the importance of adequate training of the technologists. (authors). 15 refs., 9 figs., 1 table

  6. ExStroke Pilot Trial of the effect of repeated instructions to improve physical activity after ischaemic stroke: a multinational randomised controlled clinical trial

    DEFF Research Database (Denmark)

    Boysen, Gudrun; Krarup, Lars-Henrik; Zeng, Xianrong

    2009-01-01

    training programme before discharge and at five follow-up visits during 24 months. Control patients had follow-up visits with the same frequency but without instructions in physical activity. MAIN OUTCOME MEASURES: Physical activity assessed with the Physical Activity Scale for the Elderly (PASE) at each......OBJECTIVES: To investigate if repeated verbal instructions about physical activity to patients with ischaemic stroke could increase long term physical activity. DESIGN: Multicentre, multinational, randomised clinical trial with masked outcome assessment. SETTING: Stroke units in Denmark, China...... infarction, or falls and fractures. CONCLUSION: Repeated encouragement and verbal instruction in being physically active did not lead to a significant increase in physical activity measured by the PASE score. More intensive strategies seem to be needed to promote physical activity after ischaemic stroke...

  7. Environmental radioactivity: the importance of controlling exposure of the public: some experiences in Cuba

    International Nuclear Information System (INIS)

    Fernandez Gomez, Isis Maria

    2008-01-01

    The nuclear power is offering considerable advantages, it is considering the option to produce energy and the economy has moved in favour of the nuclear power. Therefore, the security is important within of the industry because ensures the control of public exposure and the environment and it plays a crucial role. Public exposure refers to exposure that is not of the direct work with ionizing radiation or the application of nuclear techniques in medical treatment and diagnosis. There are potential sources of discharges into the environment as the spent fuel and the waste disposal. Some of the routes of exposure are atmospheric discharge, liquid discharge, irrigation, environment, decomposition of the rain, food chains, etc. International regulations on subject of radiological safety are set by the IAEA and have a hierarchical order: fundamentals, requirements and guidelines. The International Commission of Radiological Protection and the Committee of the General Assembly of the United Nations are described in the research. The action is exposed in Cuba with regard to nuclear programs that have been realized or that are executed in relation to the control of the exposure of the public in existing applications. It mentions the centralized management of radioactive rights generated, the control of other sources of exposure, and the Red Nacional de Vigilancia Radiologica Ambiental. It also includes numerical data of studies realized on the extent of the sources of public exposure, the external doses received by the Cuban population product of environmental sources of radiation, the estimating of the doses received by the Cuban population by the incorporation of radionuclides present in the water and food. Likewise, the radioactive environmental funds; the phosphate mining; the protection and extraction of oil and the presence of radon inside the house are shown. The exposure to gamma radiation in thermal spas; the exposure to environmental sources of radiation

  8. Analytical quality control in studies of environmental exposure to mercury

    International Nuclear Information System (INIS)

    Byrne, A.R.; Prosenc, N.; Smerke, J.; Horvat, M.

    1995-01-01

    The work of the laboratory for quality control in this co-ordinated project for the period from November 1993 to June 1994 is presented. The major effort was devoted to assisting in establishing the homogeneity and total methylmercury levels in two new hair reference materials prepared as control materials for the project, numbered 085 (spiked) and 086 (natural level). Results for some hair materials from participants are also given. (author)

  9. Trends in Teenagers' Nonopiod Substance Exposures Reported to Poison Control Centers, 2010-2015.

    Science.gov (United States)

    Wright, Brad; Mestan, Samantha; Ahrens, Monica; Bottei, Edward

    2018-05-01

    To describe current trends in nonopioid substance exposures and associated outcomes among teenagers nationwide. In this cross-sectional study, we used 2010-2015 data from the American Association of Poison Control Centers' National Poison Data System and Poisson tests to document trends in the rate of calls to poison control centers involving adolescents stratified by sex, exposures by substance category, proportion of intentional exposures, and severity of exposures. The number of calls per 1000 persons increased from 5.7 to 6.8 for teenage girls and decreased from 4.7 to 4.3 for boys. Reported exposures to prescription and over-the-counter medications and illicit street drugs increased between 24% and 73%, and reported opioid exposures decreased by 16%. Among teenage girls, intentional exposures increased from 57% to 68%, with cases increasingly managed in health care facilities and more likely to result in worse health outcomes. The increase in intentional nonopioid substance exposures among teenage girls, with serious and potentially life-threatening consequences, is a matter of serious concern. Similar trends were not observed among teenage boys. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Initial experience of tritium exposure control at JET

    International Nuclear Information System (INIS)

    Patel, B.; Campling, D.C.; Schofield, P.A.; Macheta, P.; Sandland, K.

    1998-01-01

    Some of the safety procedures and controls in place for work with tritium are described, and initial operational experience of handling tritium is discussed. A description is given of work to rectify a water leak in a JET neutral beam heating component, which involved man-access to a confined volume to perform repairs, at tritium levels about 100 DAC (80 MBq/m 3 . HTO). Control measures involving use of purge and extract ventilation, and of personal protection using air-fed pressurized suits are described. Results are given of the internal doses to project staff and of atmospheric discharges of tritium during the repair outage. (P.A.)

  11. Virtual reality exposure therapy for social anxiety disorder: a randomized controlled trial.

    Science.gov (United States)

    Anderson, Page L; Price, Matthew; Edwards, Shannan M; Obasaju, Mayowa A; Schmertz, Stefan K; Zimand, Elana; Calamaras, Martha R

    2013-10-01

    This is the first randomized trial comparing virtual reality exposure therapy to in vivo exposure for social anxiety disorder. Participants with a principal diagnosis of social anxiety disorder who identified public speaking as their primary fear (N = 97) were recruited from the community, resulting in an ethnically diverse sample (M age = 39 years) of mostly women (62%). Participants were randomly assigned to and completed 8 sessions of manualized virtual reality exposure therapy, exposure group therapy, or wait list. Standardized self-report measures were collected at pretreatment, posttreatment, and 12-month follow-up, and process measures were collected during treatment. A standardized speech task was delivered at pre- and posttreatment, and diagnostic status was reassessed at 3-month follow-up. Analysis of covariance showed that, relative to wait list, people completing either active treatment significantly improved on all but one measure (length of speech for exposure group therapy and self-reported fear of negative evaluation for virtual reality exposure therapy). At 12-month follow-up, people showed significant improvement from pretreatment on all measures. There were no differences between the active treatments on any process or outcome measure at any time, nor differences on achieving partial or full remission. Virtual reality exposure therapy is effective for treating social fears, and improvement is maintained for 1 year. Virtual reality exposure therapy is equally effective as exposure group therapy; further research with a larger sample is needed, however, to better control and statistically test differences between the treatments.

  12. A multiple objective test assembly approach for exposure control problems in Computerized Adaptive Testing

    Directory of Open Access Journals (Sweden)

    Theo J.H.M. Eggen

    2010-01-01

    Full Text Available Overexposure and underexposure of items in the bank are serious problems in operational computerized adaptive testing (CAT systems. These exposure problems might result in item compromise, or point at a waste of investments. The exposure control problem can be viewed as a test assembly problem with multiple objectives. Information in the test has to be maximized, item compromise has to be minimized, and pool usage has to be optimized. In this paper, a multiple objectives method is developed to deal with both types of exposure problems. In this method, exposure control parameters based on observed exposure rates are implemented as weights for the information in the item selection procedure. The method does not need time consuming simulation studies, and it can be implemented conditional on ability level. The method is compared with Sympson Hetter method for exposure control, with the Progressive method and with alphastratified testing. The results show that the method is successful in dealing with both kinds of exposure problems.

  13. Human bromethalin exposures reported to a U.S. Statewide Poison Control System.

    Science.gov (United States)

    Huntington, Serena; Fenik, Yelena; Vohra, Rais; Geller, Richard J

    2016-03-01

    Bromethalin is an increasingly used alternative to long-acting anticoagulant and cholecalciferol rodenticides. There are few reports of human exposures, and no existing professional society guidelines on medical management of bromethalin ingestions. The aim of this retrospective data review is to characterize bromethalin exposures reported to the California Poison Control System (CPCS) between 1997 and 2014. This is an observational retrospective case review of our statewide poison control system's electronic medical records. Following Institutional Board Review and Research Committee approvals, poison center exposures related to bromethalin were extracted using substance code and free text search strategies. Case notes of bromethalin exposures were reviewed for demographic, clinical, laboratory, and outcome information; inclusion criteria for the study was single-substance, human exposure to bromethalin. There were 129 calls related to human bromethalin exposures (three cases met exclusion criteria). The age range of cases was 7 months-90 years old, with the majority of exposures (89 cases; 70.6%), occurring in children younger than 5 years of age (median age of 2 years). Most exposures occurred in the pediatric population as a result of exploratory oral exposure. One hundred and thirteen patients (89.7%) had no effects post exposure, while 10 patients (7.9%) had a minor outcome. Adverse effects were minor, self-limited, and mostly gastrointestinal upset. There were no moderate, major, or fatal effects in our study population. The approximate ingested dose, available in six cases, ranged from 0.067 mg/kg to 0.3 mg/kg (milligrams of bromethalin ingested per kilogram of body weight), and no dose-symptom threshold could be established from this series. Exposures were not confirmed through urine or serum laboratory testing. The prognosis for most accidental ingestions appears to be excellent. However, bromethalin exposures may result in a higher number of

  14. Rationale and design of REACT: a randomised controlled trial assessing the effectiveness of home-collection to increase chlamydia retesting and detect repeat positive tests.

    Science.gov (United States)

    Smith, Kirsty S; Hocking, Jane S; Chen, Marcus; Fairley, Christopher K; McNulty, Anna; Read, Phillip; Bradshaw, Catriona S; Tabrizi, Sepehr N; Wand, Handan; Saville, Marion; Rawlinson, William; Garland, Suzanne M; Donovan, Basil; Kaldor, John M; Guy, Rebecca

    2014-04-24

    Repeat infection with Chlamydia trachomatis is common and increases the risk of sequelae in women and HIV seroconversion in men who have sex with men (MSM). Despite guidelines recommending chlamydia retesting three months after treatment, retesting rates are low. We are conducting the first randomised controlled trial to assess the effectiveness of home collection combined with short message service (SMS) reminders on chlamydia retesting and reinfection rates in three risk groups. The REACT (retest after Chlamydia trachomatis) trial involves 600 patients diagnosed with chlamydia: 200 MSM, 200 women and 200 heterosexual men recruited from two Australian sexual health clinics where SMS reminders for retesting are routine practice. Participants will be randomised to the home group (3-month SMS reminder and home-collection) or the clinic group (3-month SMS reminder to return to the clinic). Participants in the home group will be given the choice of attending the clinic if they prefer. The mailed home-collection kit includes a self-collected vaginal swab (women), UriSWAB (Copan) for urine collection (heterosexual men), and UriSWAB plus rectal swab (MSM). The primary outcome is the retest rate at 1-4 months after a chlamydia diagnosis, and the secondary outcomes are: the repeat positive test rate; the reinfection rate; the acceptability of home testing with SMS reminders; and the cost effectiveness of home testing. Sexual behaviour data collected via an online survey at 4-5 months, and genotyping of repeat infections, will be used to discriminate reinfections from treatment failures. The trial will be conducted over two years. An intention to treat analysis will be conducted. This study will provide evidence about the effectiveness of home-collection combined with SMS reminders on chlamydia retesting, repeat infection and reinfection rates in three risk groups. The trial will determine client acceptability and cost effectiveness of this strategy. Australian and New

  15. Regulatory control of low level radiation exposure in Tanzania

    International Nuclear Information System (INIS)

    Nyanda, A.M.; Muhogora, W.E.

    1997-01-01

    In Tanzania, the radiation protection law was issued in 1983. Under this law, the National Radiation Commission is responsible for safe uses of ionizing radiation. The regulatory control of the resulting doses from the uses of radiation sources in medicine, industry, research and teaching is presented. The system of control reflects the existing interactions between the National Radiation Commission and users through the established radiation protection infrastructure. From the national dose registry data, it is found that the highest annual individual doses over 10 years ago, came from less than 5% of total monitored workers and were in the range 10 - 15 mSv y -1 . The experienced radiation levels in uncontrolled areas of potential workplaces is less than 1 μSv h -1 . The possibility for associating such low dose levels to the effectiveness of the existing regulatory dose control framework is discussed. Despite of this achievement, the need to improve further the radiation protection and safety programs is found necessary. (author)

  16. Opioid gene expression changes and post-translational histone modifications at promoter regions in the rat nucleus accumbens after acute and repeated 3,4-methylenedioxy-methamphetamine (MDMA) exposure.

    Science.gov (United States)

    Caputi, Francesca Felicia; Palmisano, Martina; Carboni, Lucia; Candeletti, Sanzio; Romualdi, Patrizia

    2016-12-01

    The recreational drug of abuse 3,4-methylenedioxymethamphetamine (MDMA) has been shown to produce neurotoxic damage and long-lasting changes in several brain areas. In addition to the involvement of serotoninergic and dopaminergic systems, little information exists about the contribution of nociceptin/orphaninFQ (N/OFQ)-NOP and dynorphin (DYN)-KOP systems in neuronal adaptations evoked by MDMA. Here we investigated the behavioral and molecular effects induced by acute (8mg/kg) or repeated (8mg/kg twice daily for seven days) MDMA exposure. MDMA exposure affected body weight gain and induced hyperlocomotion; this latter effect progressively decreased after repeated administration. Gene expression analysis indicated a down-regulation of the N/OFQ system and an up-regulation of the DYN system in the nucleus accumbens (NAc), highlighting an opposite systems regulation in response to MDMA exposure. Since histone modifications have been strongly associated to the addiction-related maladaptive changes, we examined two permissive (acH3K9 and me3H3K4) and two repressive transcription marks (me3H3K27 and me2H3K9) at the pertinent opioid gene promoter regions. Chromatin immunoprecipitation assays revealed that acute MDMA increased me3H3K4 at the pN/OFQ, pDYN and NOP promoters. Following acute and repeated treatment a significant decrease of acH3K9 at the pN/OFQ promoter was observed, which correlated with gene expression results. Acute treatment caused an acH3K9 increase and a me2H3K9 decrease at the pDYN promoter which matched its mRNA up-regulation. Our data indicate that the activation of the DYNergic stress system together with the inactivation of the N/OFQergic anti-stress system contribute to the neuroadaptive actions of MDMA and offer novel epigenetic information associated with MDMA abuse. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Important exposure controls for protection against antineoplastic agents: Highlights for oncology health care workers.

    Science.gov (United States)

    Alehashem, Maryam; Baniasadi, Shadi

    2018-01-01

    A great number of antineoplastic drugs (ANPDs) are used globally in cancer treatment. Due to their adverse health effects, occupational exposure to ANPDs is considered a potential health risk to health care workers. The current study aimed to evaluate safe-handling practices of ANPDs, exposure controls, and adverse health implications for health care providers exposed to ANDPs. Prevention measures, including engineering, administrative, and work practice controls, as well as personal protective equipment (PPE), were recorded daily through a questionnaire for six weeks. Acute adverse health effects experienced by health care workers were also documented. The implemented exposure controls for preparation, administration, cleaning, and waste disposal were not in accordance with the safe handling guidelines. Central nervous system disorders (26.33%) were the most frequent acute adverse effects reported by health care workers. A significant correlation was found between the number of experienced adverse effects and handling characteristics, including the number of preparations (r = 0.38, p health care workers were in danger of exposure to ANPDs and experienced acute adverse health effects. Implementation of appropriate exposure controls is required to prevent occupational exposure to ANPDs.

  18. Occupational and public field exposure from communication, navigation, and radar systems used for air traffic control.

    Science.gov (United States)

    Joseph, Wout; Goeminne, Francis; Vermeeren, Günter; Verloock, Leen; Martens, Luc

    2012-12-01

    Electromagnetic exposure (occupational and general public) to 14 types of air traffic control (ATC) systems is assessed. Measurement methods are proposed for in situ exposure assessment of these ATC systems. In total, 50 sites are investigated at 1,073 locations in the frequency range of 255 kHz to 24 GHz. For all installations, typical and maximal exposure values for workers and the general public are provided. Two of the 14 types of systems, Non-Directional Beacons (NDB) (up to 881.6 V m) and Doppler Very High Frequency (VHF) Omni-directional Range (DVOR) (up to 92.3 V m), exhibited levels requiring recommended minimum distances such that the ICNIRP reference levels are not exceeded. Cumulative exposure of all present radiofrequency (RF) sources is investigated, and it is concluded that the ATC source dominates the total exposure in its neighborhood.

  19. Entry into the nuclear pore complex is controlled by a cytoplasmic exclusion zone containing dynamic GLFG-repeat nucleoporin domains.

    Science.gov (United States)

    Fiserova, Jindriska; Spink, Matthew; Richards, Shane A; Saunter, Christopher; Goldberg, Martin W

    2014-01-01

    Nuclear pore complexes (NPCs) mediate nucleocytoplasmic movement. The central channel contains proteins with phenylalanine-glycine (FG) repeats, or variations (GLFG, glycine-leucine-phenylalanine-glycine). These are 'intrinsically disordered' and often represent weak interaction sites that become ordered upon interaction. We investigated this possibility during nuclear transport. Using electron microscopy of S. cerevisiae, we show that NPC cytoplasmic filaments form a dome-shaped structure enclosing GLFG domains. GLFG domains extend out of this structure and are part of an 'exclusion zone' that might act as a partial barrier to entry of transport-inert proteins. The anchor domain of a GLFG nucleoporin locates exclusively to the central channel. By contrast, the localisation of the GLFG domains varied between NPCs and could be cytoplasmic, central or nucleoplasmic and could stretch up to 80 nm. These results suggest a dynamic exchange between ordered and disordered states. In contrast to diffusion through the NPC, transport cargoes passed through the exclusion zone and accumulated near the central plane. We also show that movement of cargo through the NPC is accompanied by relocation of GLFG domains, suggesting that binding, restructuring and movement of these domains could be part of the translocation mechanism.

  20. Management and control aimed at reducing potential exposure of cobalt irradiation units

    International Nuclear Information System (INIS)

    Yan Yukui

    2003-01-01

    This paper is intended to address the problems of the management and control of potential exposure of cobalt irradiation units and analyze both the current situation and the resultant accident reasons associated with irradiation units, with the necessary control measures provided to reduce potential exposure. The concepts of defense in depth and excellent engineering practice are introduced in design to provide the units with sufficient redundancy. In the course of scientific management, the qualified applicants or registers devoted, strictly and effectively, their oversight, monitoring and regulation to the irradiation units. The effective management and control are achieved through safety analysis and assessment, reasonable regulatory system and source decommissioning system. (authors)

  1. Control banding tools for occupational exposure assessment of nanomaterials - Ready for use in a regulatory context?

    DEFF Research Database (Denmark)

    Liguori, Biase; Hansen, Steffen Foss; Baun, Anders

    2016-01-01

    area of concern. Therefore, a number of Control Banding (CB)-based tools have been developed in order to assess and manage the potential risks associated with occupational exposure to nanomaterials. In this paper we provide a comparative analysis of different nanomaterial-specific types of control-banding/risk...... developed for different purposes, with different application domains and inclusion criteria. The exposure assessments and derived risk levels are based on different concepts and assumptions and outputs in different formats. The use of requested input parameters for exposure assessment differ greatly among...... the tools. Therefore, direct inter-comparison and combination of the different models into a larger holistic framework is not immediately possible. Harmonization of input parameters and output could allow establishment of an exposure assessment framework with different levels of information requirements....

  2. A controlled study of virtual reality exposure therapy for the fear of flying.

    Science.gov (United States)

    Rothbaum, B O; Hodges, L; Smith, S; Lee, J H; Price, L

    2000-12-01

    Fear of flying (FOF) affects an estimated 10-25% of the population. Patients with FOF (N = 49) were randomly assigned to virtual reality exposure (VRE) therapy, standard exposure (SE) therapy, or a wait-list (WL) control. Treatment consisted of 8 sessions over 6 weeks, with 4 sessions of anxiety management training followed by either exposure to a virtual airplane (VRE) or exposure to an actual airplane at the airport (SE). A posttreatment flight on a commercial airline measured participants' willingness to fly and anxiety during flight immediately after treatment. The results indicated that VRE and SE were both superior to WL, with no differences between VRE and SE. The gains observed in treatment were maintained at a 6-month follow up. By 6 months posttreatment, 93% of VRE participants and 93% of SE participants had flown. VRE therapy and SE therapy for treatment of FOF were unequivocally supported in this controlled study.

  3. Stress Exposure and Depression in Disadvantaged Women: The Protective Effects of Optimism and Perceived Control

    Science.gov (United States)

    Grote, Nancy K.; Bledsoe, Sarah E.; Larkin, Jill; Lemay, Edward P., Jr.; Brown, Charlotte

    2007-01-01

    In the present study, the authors predicted that the individual protective factors of optimism and perceived control over acute and chronic stressors would buffer the relations between acute and chronic stress exposure and severity of depression, controlling for household income, in a sample of financially disadvantaged women. Ninety-seven African…

  4. Risk Communication in EPA's Controlled Inhalation Exposure Studies and in Support.

    Science.gov (United States)

    Resnik, David

    2017-01-01

    On March 28, 2017, the National Academy of Sciences, Engineering, and Medicine (NASEM) released a much-anticipated report on the Environmental Protection Agency's controlled human inhalation exposure studies. This essay reviews the ethical controversies that led to the genesis of the report, summarizes its key findings, and comments on its approach to informing human subjects about the risks of inhalation exposure studies. NASEM's report makes a valuable contribution to our understanding of the scientific and ethical issues involved in conducting human inhalation exposure studies. Its definition of "reasonably foreseeable risks" provides useful guidance to investigators, research participants, and institutional review board members.

  5. In situ exposure to non-directional beacons for air traffic control.

    Science.gov (United States)

    Joseph, Wout; Goeminne, Francis; Vermeeren, Günter; Verloock, Leen; Martens, Luc

    2012-04-01

    In situ electromagnetic field exposure of workers and the general public due to non-directional beacons (NDB) for air traffic control is assessed and characterized. For occupational exposure, the maximal measured electric field value is 881.6 V/m and the maximal magnetic field value is 9.1 A/m. The maximum electric fields exceed the International Commission on Non-Ionizing Radiation Protection (ICNIRP) reference levels at all seven NDB sites, and the magnetic fields at two of the seven NDB sites (occupational exposure). Recommendations and compliance distances for workers and the general public are provided. © 2012 Wiley Periodicals, Inc.

  6. Control of occupational exposure using remote monitoring systems

    Energy Technology Data Exchange (ETDEWEB)

    Lunn, M. P. [British Energy Generation Ltd. Sizewell B Power Station, Leiston, Suffolk (United Kingdom)

    2004-07-01

    Advances in electronic dosimetry, portable radio technology and digital video have enabled the development of Remote Monitoring Systems (RMS) that provide a powerful dose control tool for the Operational Health Physicist. North American utilities have led the implementation of these systems, often with coverage of the entire plant, feeding back to a centralized control room. These large-scale systems typically cost around EURO 500,000. In Europe, and especially the UK, implementation of RMS technology has been slower and on a smaller scale. US utilities have justified the high capital cost of their systems by significantly reducing the number of contract RP technicians required during refuelling outages, saving up to EURO 1,000,000. In the UK, the number of contract RP technicians employed during outages is already minimal, and with the generally low dose rates found on Gas-Cooled Reactors, RP engineers have traditionally considered RMS to be an extravagance. However, the commissioning of the UK's first PWR and a significant increase in the number of AGR Vessel entries, have increased the radiological protection challenges facing the British Health Physicist, thus prompting a re-evaluation of this view. The benefit derived from a system that combines telemetry, video and voice communications is synergistic. We found that the system can be used in a variety of ways to significantly enhance radiological protection control in high radiation areas and to significantly reduce the dose received by RP staff covering such jobs. Indeed, it is estimated that the use of RMS saved at least 10 man.mSv of Radiological Protection dose during RF06 However, it is important to note that RMS is a monitoring tool to support existing monitoring techniques and arrangements. Suitably qualified and experienced staff are required to interpret the data and provide suitable advice to the work party. In addition, detailed training on the limitations of RMS, explicit procedures for

  7. A Comparison of Item Selection Techniques and Exposure Control Mechanisms in CATs Using the Generalized Partial Credit Model.

    Science.gov (United States)

    Pastor, Dena A.; Dodd, Barbara G.; Chang, Hua-Hua

    2002-01-01

    Studied the impact of using five different exposure control algorithms in two sizes of item pool calibrated using the generalized partial credit model. Simulation results show that the a-stratified design, in comparison to a no-exposure control condition, could be used to reduce item exposure and overlap and increase pool use, while degrading…

  8. Development of risk-based nanomaterial groups for occupational exposure control

    International Nuclear Information System (INIS)

    Kuempel, E. D.; Castranova, V.; Geraci, C. L.; Schulte, P. A.

    2012-01-01

    Given the almost limitless variety of nanomaterials, it will be virtually impossible to assess the possible occupational health hazard of each nanomaterial individually. The development of science-based hazard and risk categories for nanomaterials is needed for decision-making about exposure control practices in the workplace. A possible strategy would be to select representative (benchmark) materials from various mode of action (MOA) classes, evaluate the hazard and develop risk estimates, and then apply a systematic comparison of new nanomaterials with the benchmark materials in the same MOA class. Poorly soluble particles are used here as an example to illustrate quantitative risk assessment methods for possible benchmark particles and occupational exposure control groups, given mode of action and relative toxicity. Linking such benchmark particles to specific exposure control bands would facilitate the translation of health hazard and quantitative risk information to the development of effective exposure control practices in the workplace. A key challenge is obtaining sufficient dose–response data, based on standard testing, to systematically evaluate the nanomaterials’ physical–chemical factors influencing their biological activity. Categorization processes involve both science-based analyses and default assumptions in the absence of substance-specific information. Utilizing data and information from related materials may facilitate initial determinations of exposure control systems for nanomaterials.

  9. Development of risk-based nanomaterial groups for occupational exposure control

    Science.gov (United States)

    Kuempel, E. D.; Castranova, V.; Geraci, C. L.; Schulte, P. A.

    2012-09-01

    Given the almost limitless variety of nanomaterials, it will be virtually impossible to assess the possible occupational health hazard of each nanomaterial individually. The development of science-based hazard and risk categories for nanomaterials is needed for decision-making about exposure control practices in the workplace. A possible strategy would be to select representative (benchmark) materials from various mode of action (MOA) classes, evaluate the hazard and develop risk estimates, and then apply a systematic comparison of new nanomaterials with the benchmark materials in the same MOA class. Poorly soluble particles are used here as an example to illustrate quantitative risk assessment methods for possible benchmark particles and occupational exposure control groups, given mode of action and relative toxicity. Linking such benchmark particles to specific exposure control bands would facilitate the translation of health hazard and quantitative risk information to the development of effective exposure control practices in the workplace. A key challenge is obtaining sufficient dose-response data, based on standard testing, to systematically evaluate the nanomaterials' physical-chemical factors influencing their biological activity. Categorization processes involve both science-based analyses and default assumptions in the absence of substance-specific information. Utilizing data and information from related materials may facilitate initial determinations of exposure control systems for nanomaterials.

  10. SU-F-I-67: Neurometabolic Effect Induced by Repeated Exposure to Dizocilpine On Prefrontal Cortex of Schizophrenic Animal Model Using In Vivo Proton Magnetic Resonance Spectroscopy at 9.4 T

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, C-H; Lim, S-I [Department of Biomedical Engineering, and Research Institute of Biomedical Engineering, The Catholic University of Korea College of Medicine, Seoul (Korea, Republic of); Asan Institute for Life Sciences, Asan Medical Center, Seoul (Korea, Republic of); Song, K-H; Choe, B-Y [Department of Biomedical Engineering, and Research Institute of Biomedical Engineering, The Catholic University of Korea College of Medicine, Seoul (Korea, Republic of); Woo, D-C [Asan Institute for Life Sciences, Asan Medical Center, Seoul (Korea, Republic of)

    2016-06-15

    Purpose: Repeated exposure of dizocilpine (MK-801) can provide a pathophysiological model for progressive development of schizophrenia. In vivo proton magnetic resonance spectroscopy ({sup 1}H MRS) was widely used for non-invasive measurement of neurometabolites, and assessment of disease-induced neurometabolic alterations. The purpose of this study was to investigate neurometabolic alteration in prefrontal cortex (PFC) with respect to progression (from first-episode to chronic stage) of schizophrenia by using in vivo {sup 1}H MRS. Methods: We used high-field {sup 1}H MRS to investigate the neurometabolic alteration in the PFC region of the rats (N = 13) by comparing before and after 6 day of MK-801 (0.5 mg/kg) treatment. A point-resolved spectroscopy (PRESS) sequence was used to obtain spectra in a 22.5 µL of volume of interest carefully located in PFC region with parameters like follow; repetition time, 5000ms; echo time (TE), 13.4 ms; averages = 256. Another experiment group (N = 11) were conducted behavior test by recording the behavior for 20 min. Results: All the rats showed hyperlocomotion, stereotyped behaviors before initiation of MRS. Significantly increased level (N = 7, p < 0.05) of N-acetylasrparate (NAA), glutamate (Glu), taurine and decreased level (N = 6, p < 0.05) of NAA, Glu and phosphocreatine were observed between baseline and day 6. Both metabolic alterations are consistent with results of first-episode and chronic schizophrenia respectively. Conclusion: From our findings, the repeated MK-801 model could be a pathophysiological model which can provide an insight into the transition from first-episode to chronic stage. This is first time to investigate effects of repeated MK-801 using high-field in vivo 1H MRS. We expect our findings can contribute to combining previous diverging results into one pathophysiological interpretation, which can postulate the origin of diverging results to the progression of schizophrenia.

  11. SU-F-I-67: Neurometabolic Effect Induced by Repeated Exposure to Dizocilpine On Prefrontal Cortex of Schizophrenic Animal Model Using In Vivo Proton Magnetic Resonance Spectroscopy at 9.4 T

    International Nuclear Information System (INIS)

    Yoo, C-H; Lim, S-I; Song, K-H; Choe, B-Y; Woo, D-C

    2016-01-01

    Purpose: Repeated exposure of dizocilpine (MK-801) can provide a pathophysiological model for progressive development of schizophrenia. In vivo proton magnetic resonance spectroscopy ("1H MRS) was widely used for non-invasive measurement of neurometabolites, and assessment of disease-induced neurometabolic alterations. The purpose of this study was to investigate neurometabolic alteration in prefrontal cortex (PFC) with respect to progression (from first-episode to chronic stage) of schizophrenia by using in vivo "1H MRS. Methods: We used high-field "1H MRS to investigate the neurometabolic alteration in the PFC region of the rats (N = 13) by comparing before and after 6 day of MK-801 (0.5 mg/kg) treatment. A point-resolved spectroscopy (PRESS) sequence was used to obtain spectra in a 22.5 µL of volume of interest carefully located in PFC region with parameters like follow; repetition time, 5000ms; echo time (TE), 13.4 ms; averages = 256. Another experiment group (N = 11) were conducted behavior test by recording the behavior for 20 min. Results: All the rats showed hyperlocomotion, stereotyped behaviors before initiation of MRS. Significantly increased level (N = 7, p < 0.05) of N-acetylasrparate (NAA), glutamate (Glu), taurine and decreased level (N = 6, p < 0.05) of NAA, Glu and phosphocreatine were observed between baseline and day 6. Both metabolic alterations are consistent with results of first-episode and chronic schizophrenia respectively. Conclusion: From our findings, the repeated MK-801 model could be a pathophysiological model which can provide an insight into the transition from first-episode to chronic stage. This is first time to investigate effects of repeated MK-801 using high-field in vivo 1H MRS. We expect our findings can contribute to combining previous diverging results into one pathophysiological interpretation, which can postulate the origin of diverging results to the progression of schizophrenia.

  12. Water Chemistry Control in Reducing Corrosion and Radiation Exposure at PWR Reactor

    International Nuclear Information System (INIS)

    Febrianto

    2006-01-01

    Water chemistry control plays an important role in relation to plant availability, reliability and occupational radiation exposures. Radiation exposures of nuclear plant workers are determined by the radiation rate dose and by the amount maintenance and repair work time Water chemistry has always been, from beginning of operation of power Pressurized Water Reactor, an important factor in determining the integrity of reactor components, fuel cladding integrity and minimize out of core radiation exposures. For primary system, the parameters to control the quality of water chemistry have been subject to change in time. Reactor water coolant pH need to be optimally controlled and be operated in range pH 6.9 to 7.4. At pH lower than 6.9, cause increasing the radiation exposure level and increasing coolant water pH higher than 7.4 will decrease radiation exposure level but increasing risk to fuel cladding and steam generator tube. Since beginning 90 decade, PWR water coolant pH tend to be operated at pH 7.4. This paper will discuss concerning water chemistry development in reducing corrosion and radiation exposure dose in PWR reactor. (author)

  13. [Secondary traumatization/trauma among employees in palliative care units--the products of prolonged repeated exposure to suffering and death].

    Science.gov (United States)

    Samson, Tali; Shvartzman, Pesach

    2012-11-01

    The palliative care philosophy accepts the dying process as a natural phase in the life cycle and provides quality end of life care for terminal patients and their family members. Prolonged exposure to the physical symptoms and pain, as well as the psychological, spiritual, and existential suffering of the dying patient, may be fertile ground for the development of post-traumatic stress symptoms among palliative care teams. Work-related positive outcomes (such as compassion, satisfaction and meaning) and work-related negative outcomes (such as compassion fatigue, secondary traumatization and burnout) can exist side by side, and the unique balance between them will determine the quality of life of the worker. This review presents the current knowledge about the prevalence and causes of work-related stress outcomes among palliative care teams and measurement tools that are available. The literature review discusses secondary traumatization in palliative care teams and relevant messages for the development of treatment options, burnout prevention programs and support interventions for professionals who lead the care for terminal patients in Israel.

  14. Repeated exposure of human fibroblasts to ionizing radiation reveals an adaptive response that is not mediated by interleukin-6 or TGF-β

    International Nuclear Information System (INIS)

    Dieriks, Birger; De Vos, Winnok; Baatout, Sarah; Van Oostveldt, Patrick

    2011-01-01

    Exposing cells to a low dose can protect them against a subsequent higher exposure. This phenomenon is known as adaptive response and is frequently observed in a variety of cells. Even though similarities are suspected with other non-targeted effects, such as bystander effects, the exact mechanism behind adaptive response is not fully clarified. In this study human primary fibroblasts were tested for their response to ionizing radiation (IR) after administrating a low priming dose (0.1-0.5 Gy). Both the abundance of γH2AX as a marker for double-stranded breaks and the levels of cytokines, secreted in the medium, were monitored in time. Upon challenge, IR-primed cells showed modified γH2AX spot size distributions and altered repair kinetics, consistent with an adaptive response. In addition, 24 h after priming with IR, four cytokines were significantly upregulated in the medium - GM-CSF (1.33x); IL6 (4.24x); IL8 (1.33x); TGF-β (1.46x). In order to mimick the protective effect of IR priming, we primed the cells with either IL6 or TGF-β. This did not elicit an altered γH2AX response as observed in IR-primed cells, indicating that the adaptive response in these primary fibroblasts is regulated in an IL-6 and TGF-β independent manner.

  15. Control in personnel exposure at HIRUP facility during the period 2006-2010

    International Nuclear Information System (INIS)

    Ojha, Shashikala; Suman, Santosh Kumar; Murali, S.

    2012-01-01

    HIRUP facility is designed to handle MCi of 60 Co, fabrication of sealed source, is carried out in hot cell. The design safety features allow the handling of sealed sources and other gamma emitters under suitable containment systems. The NP Unit of the facility provides personnel monitoring programmes viz., TLD/DRD monitoring for the radiation workers. 60 Co and other gamma emitters pose mainly external hazard during the handling of sealed source in hot cell. TLD is processed to assess the external exposure of personnel. Air activity and gross bg contamination at the work place is periodically monitored and reported. The TLD users of HIRUP are periodically referred for internal monitoring - whole body counting and bio-assay to estimate internal exposure. There is no reported internal exposure so far. Personnel from IAD and BRIT facility are provided with personnel monitoring coverage by HP Unit; the TLD is issued with respective institution no. as - 0283, 4288. Each person gets identified by individual TLD number, renewed TLD issue on quarterly service period. Based on job requirement such as handling of high activity, additional Wrist TLDs are provided. The used TLD of IAD and BRIT are sent for processing. The dose report obtained, enlists personnel exposure details. HP Unit does the report making to the concerned agencies enlisting the operational status, total occupational exposure of the facility (person mSv), average exposure (mSv) and few other details. Details of exposure for 2006 - 2010 (non-zero exposure cases), indicate that for IAD collective exposure got reduced by 78.5 %, average exposure got reduced by 62.6 %; for BRIT collective exposure got reduced by 58.2 %, average exposure got reduced by 46.8 %, at HIRUP facility. There is a decreasing trend in personnel exposure over the period 2006-2010, is due to HP safety protocol, on job HP surveillance and related safety measures. The personnel exposure is controlled as per ALARA, decreasing trend in the

  16. Exposure control practices for administering nitrous oxide: A survey of dentists, dental hygienists, and dental assistants.

    Science.gov (United States)

    Boiano, James M; Steege, Andrea L; Sweeney, Marie H

    2017-06-01

    Engineering, administrative, and work practice controls have been recommended for many years to minimize exposure to nitrous oxide during dental procedures. To better understand the extent to which these exposure controls are used, the NIOSH Health and Safety Practices Survey of Healthcare Workers was conducted among members of professional practice organizations representing dentists, dental hygienists and dental assistants. The anonymous, modular, web-based survey was completed by 284 dental professionals in private practice who administered nitrous oxide to adult and/or pediatric patients in the seven days prior to the survey. Use of primary engineering controls (i.e., nasal scavenging mask and/or local exhaust ventilation (LEV) near the patient's mouth) was nearly universal, reported by 93% and 96% of respondents who administered to adult (A) and pediatric (P) patients, respectively. However, adherence to other recommended precautionary practices were lacking to varying degrees, and were essentially no different among those administering nitrous oxide to adult or pediatric patients. Examples of work practices which increase exposure risk, expressed as percent of respondents, included: not checking nitrous oxide equipment for leaks (41% A; 48% P); starting nitrous oxide gas flow before delivery mask or airway mask was applied to patient (13% A; 12% P); and not turning off nitrous oxide gas flow before turning off oxygen flow to the patient (8% A; 7% P). Absence of standard procedures to minimize worker exposure to nitrous oxide (13% of all respondents) and not being trained on safe handling and administration of nitrous oxide (3%) were examples of breaches of administrative controls which may also increase exposure risk. Successful management of nitrous oxide emissions should include properly fitted nasal scavenging masks, supplemental LEV (when nitrous oxide levels cannot be adequately controlled using nasal masks alone), adequate general ventilation, regular

  17. In vitro systems toxicology approach to investigate the effects of repeated cigarette smoke exposure on human buccal and gingival organotypic epithelial tissue cultures.

    Science.gov (United States)

    Schlage, Walter K; Iskandar, Anita R; Kostadinova, Radina; Xiang, Yang; Sewer, Alain; Majeed, Shoaib; Kuehn, Diana; Frentzel, Stefan; Talikka, Marja; Geertz, Marcel; Mathis, Carole; Ivanov, Nikolai; Hoeng, Julia; Peitsch, Manuel C

    2014-10-01

    Smoking has been associated with diseases of the lung, pulmonary airways and oral cavity. Cytologic, genomic and transcriptomic changes in oral mucosa correlate with oral pre-neoplasia, cancer and inflammation (e.g. periodontitis). Alteration of smoking-related gene expression changes in oral epithelial cells is similar to that in bronchial and nasal epithelial cells. Using a systems toxicology approach, we have previously assessed the impact of cigarette smoke (CS) seen as perturbations of biological processes in human nasal and bronchial organotypic epithelial culture models. Here, we report our further assessment using in vitro human oral organotypic epithelium models. We exposed the buccal and gingival organotypic epithelial tissue cultures to CS at the air-liquid interface. CS exposure was associated with increased secretion of inflammatory mediators, induction of cytochrome P450s activity and overall weak toxicity in both tissues. Using microarray technology, gene-set analysis and a novel computational modeling approach leveraging causal biological network models, we identified CS impact on xenobiotic metabolism-related pathways accompanied by a more subtle alteration in inflammatory processes. Gene-set analysis further indicated that the CS-induced pathways in the in vitro buccal tissue models resembled those in the in vivo buccal biopsies of smokers from a published dataset. These findings support the translatability of systems responses from in vitro to in vivo and demonstrate the applicability of oral organotypical tissue models for an impact assessment of CS on various tissues exposed during smoking, as well as for impact assessment of reduced-risk products.

  18. Uncertainties of exposure-related quantities in mammographic x-ray unit quality control

    International Nuclear Information System (INIS)

    Gregory, Kent J.; Pattison, John E.; Bibbo, Giovanni

    2006-01-01

    Breast screening programs operate in many countries with mammographic x-ray units subject to stringent quality control tests. These tests include the evaluation of quantities based on exposure measurements, such as half value layer, automatic exposure control reproducibility, average glandular dose, and radiation output rate. There are numerous error sources that contribute to the uncertainty of these exposure-related quantities, some of which are unique to the low energy x-ray spectrum produced by mammographic x-ray units. For each of these exposure-related quantities, the applicable error sources and their magnitudes vary, depending on the test equipment used to make the measurement, and whether or not relevant corrections have been applied. This study has identified and quantified a range of error sources that may be used to estimate the combined uncertainty of these exposure-related quantities, given the test equipment used and corrections applied. The uncertainty analysis uses methods described by the International Standards Organization's Guide to the Expression of Uncertainty in Measurement. Examples of how these error sources combine to give the uncertainty of the exposure-related quantities are presented. Using the best test equipment evaluated in this study, uncertainties of the four exposure-related quantities at the 95% confidence interval were found to be ±1.6% (half value layer), ±0.0008 (automatic exposure control reproducibility), ±2.3% (average glandular dose), and ±2.1% (radiation output rate). In some cases, using less precise test equipment or failing to apply corrections, resulted in uncertainties more than double in magnitude

  19. Quality Assurance/Quality Control Issues for Intraoperative Planning and Adaptive Repeat Planning of Image-Guided Prostate Implants

    International Nuclear Information System (INIS)

    Zaider, Marco; Cohen, Gilad; Meli, Jerome; Rosenfeld, Anatoly B.

    2008-01-01

    The quality assurance/quality control purpose is this. We design a treatment plan, and we wish to be as certain as reasonably possible that the treatment is delivered as planned. In the case of conventionally planned prostate brachytherapy, implementing to the letter the implantation plan is rarely attainable and therefore can require adaptive replanning (a quality control issue). The reasons for this state of affairs include changes in the prostate shape and volume during implantation and treatment delivery (e.g., edema resolution) and unavoidable inaccuracy in the placement of the seeds in the prostate. As a result, quality-control activities (e.g., the need to monitor-ideally, on the fly-the target and urethral and rectal dosage) must be also addressed

  20. Acute Mountain Sickness at 4500 m is not Altered by Repeated Eight-Hour Exposures to 3200-3550 m Normobaric Hypoxic Equivalent,

    Science.gov (United States)

    1987-09-10

    subject had his own numbered device, which was disassembled, washed and disinfected ( benzalkonium chloride , 1:1000 v/v) each evening. 4 Subjects...fluctuations throughout the 10-day period after the reduction in altitude equivalent which occurred during day I, either in the group mean values (shown) or...significant reduction in hemoglobin concentration in the control group over the sea level treatment period, with a concomitant, but non-significant

  1. Tevatron serial data repeater system

    International Nuclear Information System (INIS)

    Ducar, R.J.

    1981-01-01

    A ten megabit per second serial data repeater system has been developed for the 6.28km Tevatron accelerator. The repeaters are positioned at each of the thirty service buildings and accommodate control and abort system communications as well as distribution of the Tevatron time and energy clocks. The repeaters are transparent to the particular protocol of the transmissions. Serial data are encoded locally as unipolar two volt signals employing the self-clocking Manchester Bi-Phase code. The repeaters modulate the local signals to low-power bursts of 50 MHz rf carrier for the 260m transmission between service buildings. The repeaters also demodulate the transmission and restructure the data for local utilization. The employment of frequency discrimination techniques yields high immunity to the characteristic noise spectrum

  2. Radiotherapy for spinal metastases from breast cancer with emphasis on local disease control and pain response using repeated MRI

    Directory of Open Access Journals (Sweden)

    Marta D. Switlyk

    2014-03-01

    Conclusion: RT provided excellent local tumor control in patients with SM. Most patients benefit from RT even in cases of progressive vertebral fracture. Pain response was not associated with imaging findings and MRI cannot be used to select patients at risk of not responding to RT.

  3. Engineering control technologies to reduce occupational silica exposures in masonry cutting and tuckpointing.

    Science.gov (United States)

    Meeker, John D; Cooper, Michael R; Lefkowitz, Daniel; Susi, Pam

    2009-01-01

    A number of tasks in construction generate worker overexposures to respirable crystalline silica dust, which is a significant contributor to occupational mortality and morbidity. This study evaluated the performance of commercially available engineering controls used in dusty construction tasks commonly performed by bricklayers. Local exhaust ventilation (LEV) controls for a portable abrasive cutter and for tuckpointing grinders were examined at a bricklayers' training center, as were two stationary wet saws. Personal breathing zone air samples were collected with and without the use of LEV or water suppression during simulated concrete block cutting, brick cutting, and tuckpointing. Compared with the use of no exposure control during block and brick cutting, the portable LEV unit significantly reduced mean respirable quartz exposures by 96% for block cutting and 91% for brick cutting (p controls (p control and no-control scenarios. These reductions with commercially available off-the-shelf tools demonstrate the effectiveness of engineering control interventions to reduce crystalline silica exposures in construction. Strategies to further improve control performance and approaches for increasing control interventions in construction are needed.

  4. Respiratory and cardiovascular response during electronic control device (ECD exposure in law enforcement trainees

    Directory of Open Access Journals (Sweden)

    Kirsten M. VanMeenen

    2013-04-01

    Full Text Available Objective: Law enforcement represents a large population of workers who may be exposed to electronic control devices (ECDs. Little is known about the potential effect of exposure to these devices on respiration or cardiovascular response during current discharge. Methods: Participants (N=23 were trainees exposed to 5 seconds of an ECD (Taser X26® as a component of training. Trainees were asked to volitionally inhale during exposure. Respiratory recordings involved a continuous waveform recorded throughout the session including during the exposure period. Heart rate was calculated from a continuous pulse oximetry recording. Results: The exposure period resulted in the cessation of normal breathing patterns in all participants and in particular a decrease in inspiratory activity. No significant changes in heart rate during ECD exposure were found. Conclusions: This is the first study to examine breathing patterns during ECD exposure with the resolution to detect changes over this discrete period of time. In contrast to reports suggesting respiration is unaffected by ECDs, present evidence suggests that voluntary inspiration is severely compromised. There is no evidence of cardiac disruption during ECD exposure.

  5. Occupational exposure to radon progeny: Importance, experience with control, regulatory approaches

    International Nuclear Information System (INIS)

    Kraus, W.; Schwedt, J.

    2002-01-01

    An overview of possible occupational exposures to enhanced natural radiation in Germany is given, based on an analysis of the German Radiological Protection Commission. So far, the most significant exposure source is radon at underground and above ground workplaces. As a result of relevant regulations, in East Germany since the 70's a systematic monitoring of exposures to radon progeny has been introduced step by step in the uranium industry, in conventional ore mining, in show caves and mines, in enterprises for securing mining areas against subsidence, in radon spas and in water works in radon affected areas. Individual exposures have been assessed. The monitoring results for the period 1975-1998 are presented. Successful protection measures leading to a significant reduction of the exposures are discussed. using workplace monitoring results and registered occupancy times. In West Germany no regulations in this area were in force. Nevertheless, voluntary measuring programmes at similar workplaces were carried out. In case of unacceptable exposures successful protection measures were implemented. At present a systematic approach to control occupational exposures to radon is laid down in the European Directive 96/29/Euratom which has to be taken over in the national legislation to come. The expected number of workplaces to be included in the radiation protection system in Germany, the recommendable way of including different workplace types taking into account appropriate reference levels, and possible approaches to a graded system of workplace and individual monitoring are discussed in detail. (author)

  6. Individual external exposures from Nevada Test Site fallout for Utah leukemia cases and controls

    International Nuclear Information System (INIS)

    Lloyd, R.D.; Gren, D.C.; Simon, S.L.; Wrenn, M.E.; Hawthorne, H.A.; Lotz, T.M.; Stevens, W.; Till, J.E.

    1990-01-01

    External gamma-ray exposures from fallout originating at the Nevada Test Site (NTS) have been assigned to 6,507 individual subjects (1,177 leukemia cases and 5,330 control subjects) who died as Utah residents between 1952 and 1981. Leukemia cases were identified, confirmed, and classified by cell type from the Utah Cancer Registry, Utah State vital records, and medical records. Residential histories were obtained from the Deceased Membership File (DMF) of the Church of Jesus Christ of Latter-day Saints (LDS), supplemented by information from the LDS Church Census Records that were taken in 1950, 1955, and 1960-62. Control subjects were selected randomly within age strata from the DMF and were frequency-matched to the cases by age at death and for sex. Individual radiation exposures were assigned as a function of residence location and time interval for each residence during the fallout period (1951-1958) using geographic exposure data taken from the literature. Temporal distribution of exposure for subjects who resided in more than one locality or who were born or died during the fallout period was determined from data of other investigators. Calculated gamma-ray exposures for each place of residence were summed for each subject to yield the exposure to fallout from the NTS

  7. Administrative and research needs associated with the control of occupational exposures in commercial nuclear power plants

    International Nuclear Information System (INIS)

    Moeller, D.W.

    1980-01-01

    This review of occupational exposures in commercial nuclear power plants in the United States of America has revealed that, although many problem areas are being adequately addressed, there is a need for additional work. Areas relative to exposure evaluation that need attention include better data collection and analysis as to when and where exposures occur, improved information on exposures from internally deposited radionuclides, improved techniques for monitoring occupational neutron exposures, and an upgrading in quality control procedures in the manufacture, calibration, use and maintenance of monitoring instruments. Areas relative to exposure control that need attention include the development of additional design and manufacturing approaches for preventing the production and build-up of key radionuclides within reactor cooling systems, the development and testing of techniques for removing those radionuclides that do accumulate in such systems, the application of risk/benefit assessments to procedures for the maintenance, repair, modification, replacement and disposal of major nuclear power plant components, such as steam generators, and the development of design features to facilitate the decommissioning of nuclear power plants. Professional radiation workers also have to be aware of the impact that the proposed major reductions in occupational dose limits would have on their operations. This impact is compounded by the fact that the number of people receiving graduate education in radiation protection in the USA is decreasing. (author)

  8. Strategies to determine and control the contributions of indoor air pollution to total inhalation exposure (STRATEX)

    DEFF Research Database (Denmark)

    Cochet, C.; Fernandes, E.O.; Jantunen, M.

    ECA-IAQ (European Collaborative Action, Urban Air, Indoor Environment and Human Exposure), 2006. Strategies to determine and control the contributions of indoor air pollution to total inhalation exposure (STRATEX), Report No 25. EUR 22503 EN. Luxembourg: Office for Official Publications...... of the European Communities It is now well established that indoor air pollution contributes significantly to the global burden of disease of the population. Therefore, the knowledge of this contribution is essential in view of risk assessment and management. The ECA STRATEX report collates the respective...... information and describes the strategies to determine population exposure to indoor air pollutants. Its major goal is to emphasise the importance of the contribution of indoor air to total air exposure. Taking this contribution into account is a prerequisite for sound risk assessment of air pollution...

  9. Repeated Remote Ischemic Conditioning Effect on Ankle-brachial Index in Diabetic Patients - A Randomized Control Trial

    Directory of Open Access Journals (Sweden)

    Najmeh Shahvazian

    2017-01-01

    Full Text Available Background: Remote ischemic preconditioning (RIPC is a phenomenon where a short period of ischemia in one organ protects against further ischemia in the other organs. We hypothesized that RIPC occurring in diabetic patients with ankle brachial index (ABI between 0.70 and 0.90 were included with peripheral arterial disease, would make the better coronary flow resulted in the increasing ABI. Materials and Methods: This randomized clinical trial study was done in the Afshar Cardiovascular Hospital in Yazd between 2013 and 2014. Sixty participants were randomly divided into two groups (intervention and control groups. The intervention group was undergoing RIPC, and the control group was tested without RIPC. RIPC was stimulated by giving three cycles of 5 min of ischemia followed by 5 min of reperfusion of both upper arms using a blood pressure cuff inflated to 200 mm Hg (n = 30. This was compared with no RIPC group which consisted of placing a deflated blood pressure cuff on the upper limbs (n = 30. Results: The mean of ABI level before intervention in the RIPC and control group group was 0.82 ± 0.055 and 0.83 ± 0.0603 (P = 0.347 respectively, with no significant difference. It was 0.86 ± 0.066 in the RIPC group compared the control 0.83 ± 0.0603 (P = 0.046. So levels of ABI were greater after intervention in the RIPC group. The mean of ABI level increase from 0.82 ± 0.05 to 0.86 ± 0.06 in RIPC group (P = 0.008. So the intervention group showed a significant increase in ABI. Conclusions: RIPC through using a simple, noninvasive technique, composing three cycles of 5 min-ischemia of both upper arms, showing a significant increase in ABI level in diabetic patients.

  10. High Seroprevalence of Leptospira Exposure in Meat Workers in Northern Mexico: A Case-Control Study

    Science.gov (United States)

    Alvarado-Esquivel, Cosme; Hernandez-Tinoco, Jesus; Sanchez-Anguiano, Luis Francisco; Ramos-Nevarez, Agar; Cerrillo-Soto, Sandra Margarita; Saenz-Soto, Leandro; Martinez-Ramirez, Lucio

    2016-01-01

    Background The seroepidemiology of Leptospira infection in workers occupationally exposed to raw meat has been poorly studied. This work aimed to determine the association between Leptospira exposure and the occupation of meat worker, and to determine the seroprevalence association with socio-demographic, work, clinical and behavioral characteristics of the meat workers studied. Methods We performed a case-control study in 124 meat workers and 124 age- and gender-matched control subjects in Durango City, Mexico. Sera of cases and controls were analyzed for anti-Leptospira IgG antibodies using a commercially available enzyme immunoassay. Data of meat workers were obtained with the aid of a questionnaire. The association of Leptospira exposure with the characteristics of meat workers was analyzed by bivariate and multivariate analyses. Results Anti-Leptospira IgG antibodies were found in 22 (17.7%) of 124 meat workers and in eight (6.5%) of 124 controls (OR = 3.12; 95% CI: 1.33 - 7.33; P = 0.006). Seroprevalence of Leptospira infection was similar between male butchers (17.6%) and female butchers (18.2%) (P = 1.00). Multivariate analysis of socio-demographic, work and behavioral variables showed that Leptospira exposure was associated with duration in the activity, rural residence, and consumption of snake meat and unwashed raw fruits. Conclusions This is the first case-control study of the association of Leptospira exposure with the occupation of meat worker. Results indicate that meat workers represent a risk group for Leptospira exposure. Risk factors for Leptospira exposure found in this study may help in the design of optimal preventive measures against Leptospira infection. PMID:26858797

  11. Neospora caninum versus Brucella spp. exposure among dairy cattle in Ethiopia: a case control study.

    Science.gov (United States)

    Asmare, Kassahun

    2014-08-01

    This case-control study aimed at assessing the relative association of Neospora caninum and Brucella species exposure with reproductive disorders. The study was carried out between October 2011 and June 2012 on 731 dairy cows sampled from 150 dairy farms in selected 17 conurbations of Ethiopia. Two hundred sixty-six of the cows were categorized as cases based on their history of abortion or stillbirth while the remaining 465 were controls. The presence of antibody to N. caninum was screened using indirect ELISA, while Brucella spp. exposure was assayed serially using Rose Bengal Plate Test and Complement Fixation Test. Exposure to N. caninum was more frequently observed among cases (23.8%) than controls (12.7%), while no significant difference (p > 0.05) was noted for Brucella exposure between the two groups. Moreover, the proportion of cows with disorders like retention of fetal membrane, endometritis and increased inter-calving period were significantly higher (p Brucella spp. exposure. However, neither N. caninum nor Brucella spp. could explain the majority (73.2%) of the reported abortions and stillbirths in cattle. Hence, this observation underscores the need for more intensive investigation on the identification of causes of the aforementioned disorders in dairy cattle of Ethiopia.

  12. In-Plane Shielding for CT: Effect of Off-Centering, Automatic Exposure Control and Shield-to-Surface Distance

    Energy Technology Data Exchange (ETDEWEB)

    Kalra, Mannudeep K.; Dang, Pragya; Singh, Sarabjeet; Saini, Sanjay; Shepard, Jo Anne O. [Massachusetts General Hospital, Boston (United States)

    2009-04-15

    To assess effects of off-centering, automatic exposure control, and padding on attenuation values, noise, and radiation dose when using in-plane bismuth-based shields for CT scanning. A 30 cm anthropomorphic chest phantom was scanned on a 64-multidetector CT, with the center of the phantom aligned to the gantry isocenter. Scanning was repeated after placing a bismuth breast shield on the anterior surface with no gap and with 1, 2, and 6 cm of padding between the shield and the phantom surface. The 'shielded' phantom was also scanned with combined modulation and off-centering of the phantom at 2 cm, 4 cm and 6 cm below the gantry isocenter. CT numbers, noise, and surface radiation dose were measured. The data were analyzed using an analysis of variance. The in-plane shield was not associated with any significant increment for the surface dose or CT dose index volume, which was achieved by comparing the radiation dose measured by combined modulation technique to the fixed mAs (p > 0.05). Irrespective of the gap or the surface CT numbers, surface noise increased to a larger extent compared to Hounsfield unit (HU) (0-6 cm, 26-55%) and noise (0-6 cm, 30-40%) in the center. With off-centering, in-plane shielding devices are associated with less dose savings, although dose reduction was still higher than in the absence of shielding (0 cm off-center, 90% dose reduction; 2 cm, 61%) (p < 0.0001). Streak artifacts were noted at 0 cm and 1 cm gaps but not at 2 cm and 6 cm gaps of shielding to the surface distances. In-plane shields are associated with greater image noise, artificially increased attenuation values, and streak artifacts. However, shields reduce radiation dose regardless of the extent of off-centering. Automatic exposure control did not increase radiation dose when using a shield.

  13. Assessing malaria control in the Kassena-Nankana district of northern Ghana through repeated surveys using the RBM tools

    Directory of Open Access Journals (Sweden)

    Adjuik Martin

    2007-08-01

    Full Text Available Abstract Background The goal of Roll Back Malaria (RBM is to reduce malaria morbidity and mortality by 50% by the year 2010, and still further thereafter until the disease becomes no more a threat to public health. To contribute to the monitoring and evaluation process of this goal, two surveys were carried out in 2000 and 2003 in households and health facilities in the Kassena-Nankana district, northern Ghana using the RBM-WHO/AFRO monitoring and evaluation tools for malaria control activities. Methods Data were collected from mothers/caretakers on signs/symptoms of the most recent malaria attack for their under five year old children; the management actions that they took and their perception of health services provided at the health facilities, bednet use, antenatal attendance and place of delivery for the most recent pregnancy, malaria prophylaxis during their last pregnancy. Community health workers and herbalist/traditional healers were also interviewed about the types of health services they provide to community members. Results The results revealed a significant improvement in knowledge among mothers/caretakers over the three-year period; this affected caretakers' initial management of illnesses of their young children. The management in terms of the type and dosage of drugs used also improved significantly (p The intensification of malaria control activities and awareness creation in this district over a three year period had started demonstrating positive results towards reducing malaria disease burden. Conclusion Periodic performance assessments through surveys as described and prompt feedback of results to stakeholders in the locality serves as a catalyst to improving malaria control in malaria-endemic countries.

  14. Using an Individual Procedure Score Before and After the Advanced Surgical Skills Exposure for Trauma Course Training to Benchmark a Hemorrhage-Control Performance Metric.

    Science.gov (United States)

    Mackenzie, Colin F; Garofalo, Evan; Shackelford, Stacy; Shalin, Valerie; Pugh, Kristy; Chen, Hegang; Puche, Adam; Pasley, Jason; Sarani, Babak; Henry, Sharon; Bowyer, Mark

    2015-01-01

    Test with an individual procedure score (IPS) to assess whether an unpreserved cadaver trauma training course, including upper and lower limb vascular exposure, improves correct identification of surgical landmarks, underlying anatomy, and shortens time to vascular control. Prospective study of performance of 3 vascular exposure and control procedures (axillary, brachial, and femoral arteries) using IPS metrics by 2 colocated and trained evaluators before and after training with the Advanced Surgical Skills Exposure for Trauma (ASSET) course. IPS, including identification of anatomical landmarks, incisions, underlying structures, and time to completion of each procedure was compared before and after training using repeated measurement models. Audio-video instrumented cadaver laboratory at University of Maryland School of Medicine. A total of 41 second to sixth year surgical residents from surgical programs throughout Mid-Atlantic States who had not previously taken the ASSET course were enrolled, 40 completed the pre- and post-ASSET performance evaluations. After ASSET training, all components of IPS increased and time shortened for each of the 3 artery exposures. Procedure steps performed correctly increased 57%, anatomical knowledge increased 43% and skin incision to passage of a vessel loop twice around the correct vessel decreased by a mean of 2.5 minutes. An overall vascular trauma readiness index, a comprehensive IPS score for 3 procedures increased 28% with ASSET Training. Improved knowledge of surface landmarks and underlying anatomy is associated with increased IPS, faster procedures, more accurate incision placement, and successful vascular control. Structural recognition during specific procedural steps and anatomical knowledge were key points learned during the ASSET course. Such training may accelerate acquisition of specific trauma surgery skills to compensate for shortened training hours, infrequent exposure to major vascular injuries, or when just

  15. Increase in oxidative stress levels following welding fume inhalation: a controlled human exposure study.

    Science.gov (United States)

    Graczyk, Halshka; Lewinski, Nastassja; Zhao, Jiayuan; Sauvain, Jean-Jacques; Suarez, Guillaume; Wild, Pascal; Danuser, Brigitta; Riediker, Michael

    2016-06-10

    Tungsten inert gas (TIG) welding represents one of the most widely used metal joining processes in industry. It has been shown to generate a large majority of particles at the nanoscale and to have low mass emission rates when compared to other types of welding. Despite evidence that TIG fume particles may produce reactive oxygen species (ROS), limited data is available for the time course changes of particle-associated oxidative stress in exposed TIG welders. Twenty non-smoking male welding apprentices were exposed to TIG welding fumes for 60 min under controlled, well-ventilated settings. Exhaled breathe condensate (EBC), blood and urine were collected before exposure, immediately after exposure, 1 h and 3 h post exposure. Volunteers participated in a control day to account for oxidative stress fluctuations due to circadian rhythm. Biological liquids were assessed for total reducing capacity, hydrogen peroxide (H2O2), malondialdehyde (MDA), and 8-hydroxy-2'-deoxyguanosine (8-OHdG) concentrations at each time point. A linear mixed model was used to assess within day and between day differences. Significant increases in the measured biomarkers were found at 3 h post exposure. At 3 h post exposure, we found a 24 % increase in plasma-H2O2 concentrations ([95%CI: 4 % to 46 %], p = 0.01); a 91 % increase in urinary-H2O2 ([2 % to 258 %], p = 0.04); a 14 % increase in plasma-8-OHdG ([0 % to 31 %], p = 0.049); and a 45 % increase in urinary-8-OHdG ([3 % to 105 %], p = 0.03). Doubling particle number concentration (PNC) exposure was associated with a 22 % increase of plasma-8-OHdG at 3 h post exposure (p = 0.01). A 60-min exposure to TIG welding fume in a controlled, well-ventilated setting induced acute oxidative stress at 3 h post exposure in healthy, non-smoking apprentice welders not chronically exposed to welding fumes. As mass concentration of TIG welding fume particles is very low when compared to other types of welding, it is

  16. A WD40-repeat protein controls proanthocyanidin and phytomelanin pigmentation in the seed coats of the Japanese morning glory.

    Science.gov (United States)

    Park, Kyeung-Il; Hoshino, Atsushi

    2012-03-15

    The protein complex composed of the transcriptional regulators containing R2R3-MYB domains, bHLH domains, and WDR in plants controls various epidermal traits, including anthocyanin and proanthocyanidin pigmentation, trichome and root hair formation, and vacuolar pH. In the Japanese morning glory (Ipomoea nil), InMYB1 having R2R3-MYB domains and InWDR1 containing WDR were shown to regulate anthocyanin pigmentation in flowers, and InWDR1 was reported to control dark-brown pigmentation and trichome formation on seed coats. Here, we report that the seed pigments of I. nil mainly comprise proanthocyanidins and phytomelanins and that these pigments are drastically reduced in the ivory seed coats of an InWDR1 mutant. In addition, a transgenic plant of the InWDR1 mutant carrying the active InWDR1 gene produced dark-brown seeds, further confirming that InWDR1 regulates seed pigmentation. Early steps in anthocyanin and proanthocyanidin biosynthetic pathways are thought to be common. In the InWDR1 mutant, none of the structural genes for anthocyanin biosynthesis that showed reduced expression in the white flowers were down-regulated in the ivory seeds, which suggests that InWDR1 may activate different sets of the structural genes for anthocyanin biosynthesis in flowers and proanthocyanidin production in seeds. As in the flowers, however, we noticed that the expression of InbHLH2 encoding a bHLH regulator was down-regulated in the seeds of the InWDR1 mutant. We discuss the implications of these results with respect to the proanthocyanidin biosynthesis in the seed coats. Copyright © 2011 Elsevier GmbH. All rights reserved.

  17. Renal effects of acute exposure to toluene. A controlled clinical trial

    DEFF Research Database (Denmark)

    Nielsen, H K; Krusell, Lars Romer; Bælum, Jesper

    1985-01-01

    Urinary excretion rates of beta 2-microglobulin and albumin were measured in 43 male printing trade workers and 43 age-matched male controls before and during exposure to toluene, 382 mg/m3, for 6 1/2 hours in a climate chamber. There were no significant changes in renal excretion rates of albumin...

  18. Enforcement of radiation safety standards and experience in the regulatory control of exposures

    Energy Technology Data Exchange (ETDEWEB)

    Krishnamurthi, T N [Health and Safety Div., Atomic Energy Regulatory Board, Mumbai (India)

    1997-11-01

    Regulatory provisions for radiation protection and their enforcement in India are discussed in this paper. The rules and regulations framed for radiation safety cover all the nuclear fuel cycle activities as well as the application of radiation sources in industrial, medical and research institutions. The enforcement aspects and experience in the control of exposures are presented. (author). 3 refs, 2 tabs.

  19. Enforcement of radiation safety standards and experience in the regulatory control of exposures

    International Nuclear Information System (INIS)

    Krishnamurthi, T.N.

    1997-01-01

    Regulatory provisions for radiation protection and their enforcement in India are discussed in this paper. The rules and regulations framed for radiation safety cover all the nuclear fuel cycle activities as well as the application of radiation sources in industrial, medical and research institutions. The enforcement aspects and experience in the control of exposures are presented. (author)

  20. A VIRTUAL REALITY EXPOSURE THERAPY FOR PTSD PATIENTS CONTROLLED BY A FUZZY LOGIC SYSTEM

    OpenAIRE

    Rosa Maria Esteves Moreira da Costa; Fernando Moraes de Oliveira; Regina Serrão Lanzillotti; Raquel Gonçalves; Luis Alfredo Vidal de Carvalho

    2014-01-01

    This paper describes the main characteristics of two integrated systems that explore Virtual Reality technology and Fuzzy Logic to support and to control the assessment of people with Post-Traumatic Stress Disorder during the Virtual Reality Exposure Therapy. The integration of different technologies, the development methodology and the test procedures are described throughout the paper.

  1. A VIRTUAL REALITY EXPOSURE THERAPY FOR PTSD PATIENTS CONTROLLED BY A FUZZY LOGIC SYSTEM

    Directory of Open Access Journals (Sweden)

    Rosa Maria Esteves Moreira da Costa

    2014-06-01

    Full Text Available This paper describes the main characteristics of two integrated systems that explore Virtual Reality technology and Fuzzy Logic to support and to control the assessment of people with Post-Traumatic Stress Disorder during the Virtual Reality Exposure Therapy. The integration of different technologies, the development methodology and the test procedures are described throughout the paper.

  2. A virtual reality exposure therapy for PTSD patients controlled by a fuzzy logic system

    OpenAIRE

    Oliveira, F. M.; Lanzillotti, R. S.; Da Costa, R. M. E. M.; Gonçalves, R.; Ventura, P.; Carvalho, L. A. V. de

    2014-01-01

    This paper describes the main characteristics of two integrated systems that explore Virtual Reality technology and Fuzzy Logic to support and to control the assessment of people with Post-Traumatic Stress Disorder during the Virtual Reality Exposure Therapy. The integration of different technologies, the development methodology and the test procedures are described throughout the paper. Peer Reviewed

  3. Occupational exposures and non-Hodgkin's lymphoma: Canadian case-control study

    Directory of Open Access Journals (Sweden)

    Spinelli John J

    2008-08-01

    Full Text Available Abstract Background The objective was to study the association between Non-Hodgkin's Lymphoma (NHL and occupational exposures related to long held occupations among males in six provinces of Canada. Methods A population based case-control study was conducted from 1991 to 1994. Males with newly diagnosed NHL (ICD-10 were stratified by province of residence and age group. A total of 513 incident cases and 1506 population based controls were included in the analysis. Conditional logistic regression was conducted to fit statistical models. Results Based on conditional logistic regression modeling, the following factors independently increased the risk of NHL: farmer and machinist as long held occupations; constant exposure to diesel exhaust fumes; constant exposure to ionizing radiation (radium; and personal history of another cancer. Men who had worked for 20 years or more as farmer and machinist were the most likely to develop NHL. Conclusion An increased risk of developing NHL is associated with the following: long held occupations of faer and machinist; exposure to diesel fumes; and exposure to ionizing radiation (radium. The risk of NHL increased with the duration of employment as a farmer or machinist.

  4. Residential traffic noise exposure and vestibular schwannoma - a Danish case-control study.

    Science.gov (United States)

    Roswall, Nina; Stangerup, Sven-Eric; Cayé-Thomasen, Per; Schüz, Joachim; Johansen, Christoffer; Jensen, Steen Solvang; Raaschou-Nielsen, Ole; Sørensen, Mette

    2017-10-01

    Few risk factors for sporadic vestibular schwannoma (VS) are known. Several studies have proposed an increased risk with occupational noise exposure, whereas no studies have investigated residential traffic noise exposure as a risk factor. The present study investigated if residential traffic noise was associated with vestibular schwannoma in a large, population-based Danish case-control study. We identified 1454 VS cases, age above 30 years at diagnosis, between 1990 and 2007. For each case, we selected two random population controls, matched on sex and year of birth. Road and railway traffic noise at the residence was calculated for all present and historical addresses between 1987 and index date. Associations between traffic noise and risk for VS were estimated using conditional logistic regression, adjusted for education, disposable personal income, cohabitation status, railway noise exposure, municipal population density, and municipal income. A two-year time-weighted mean road traffic noise exposure was associated with an adjusted odds ratio of 0.92 (0.82-1.03) for developing VS, per 10 dB increment. There was no clear trend in categorical analyses. Similarly, linear and categorical analyses of residential railway noise did not suggest an association. We found no interaction with demographics, year of diagnosis, individual and municipal socioeconomic variables, and railway noise exposure. The results did not differ by tumor side, spread or size. The present study does not suggest an association between residential traffic noise and VS.

  5. Effects of prenatal substance exposure on neurocognitive correlates of inhibitory control success and failure.

    Science.gov (United States)

    Roos, Leslie E; Beauchamp, Kathryn G; Pears, Katherine C; Fisher, Philip A; Berkman, Elliot T; Capaldi, Deborah

    2017-01-01

    Adolescents with prenatal substance (drug and alcohol) exposure exhibit inhibitory control (IC) deficits and aberrations in associated neural function. Nearly all research to date examines exposure to individual substances, and a minimal amount is known about the effects of heterogeneous exposure-which is more representative of population exposure levels. Using functional magnetic resonance imaging (fMRI), we investigated IC (Go/NoGo) in heterogeneously exposed (n = 7) vs. control (n = 7) at-risk adolescents (ages 13-17). The fMRI results indicated multiple IC processing differences consistent with a more immature developmental profile for exposed adolescents (Exposed  >  Nonexposed: NoGo > Go: right ventrolateral prefrontal cortex, right cuneus, and left inferior parietal lobe; NoGo > false alarm: occipital lobe; Go > false alarm: right anterior prefrontal cortex). Simple effects suggest exposed adolescents exhibited exaggerated correct trial but decreased incorrect trial activation. Results provide initial evidence that prenatal exposure across substances creates similar patterns of atypical brain activation to IC success and failure.

  6. Pediatric Exposures to Topical Benzocaine Preparations Reported to a Statewide Poison Control System

    Directory of Open Access Journals (Sweden)

    Rais Vohra

    2017-07-01

    Full Text Available Introduction: Topical benzocaine is a local anesthetic commonly used to relieve pain caused by teething, periodontal irritation, burns, wounds, and insect bites. Oral preparations may contain benzocaine concentrations ranging from 7.5% to 20%. Pediatric exposure to such large concentrations may result in methemoglobinemia and secondarily cause anemia, cyanosis, and hypoxia. Methods: This is a retrospective study of exposures reported to a statewide poison control system. The electronic health records were queried for pediatric exposures to topical benzocaine treated at a healthcare facility from 2004 to 2014. Cases of benzocaine exposure were reviewed for demographic and clinical information, and descriptive statistical analysis was performed. Results: The query resulted in 157 cases; 58 were excluded due to co-ingestants, or miscoding of non-benzocaine exposures. Children four years of age and younger represented the majority of cases (93% with a median age of 1 year. There were 88 cases of accidental/ exploratory exposure, while 6 cases resulted from therapeutic application or error, 4 cases from adverse reactions, and 1 case from an unknown cause. Asymptomatic children accounted for 75.5% of cases, but major clinical effects were observed in 5 patients. Those with serious effects were exposed to a range of benzocaine concentrations (7.5–20%, with 4 cases reporting methemoglobin levels between 20.2%–55%. Methylene blue was administered in 4 of the cases exhibiting major effects. Conclusion: The majority of exposures were accidental ingestions by young children. Most exposures resulted in minor to no effects. However, some patients required treatment with methylene blue and admission to a critical care unit. Therapeutic application by parents or caregivers may lead to adverse effects from these commonly available products.

  7. Pediatric Exposures to Topical Benzocaine Preparations Reported to a Statewide Poison Control System.

    Science.gov (United States)

    Vohra, Rais; Huntington, Serena; Koike, Jennifer; Le, Kevin; Geller, Richard J

    2017-08-01

    Topical benzocaine is a local anesthetic commonly used to relieve pain caused by teething, periodontal irritation, burns, wounds, and insect bites. Oral preparations may contain benzocaine concentrations ranging from 7.5% to 20%. Pediatric exposure to such large concentrations may result in methemoglobinemia and secondarily cause anemia, cyanosis, and hypoxia. This is a retrospective study of exposures reported to a statewide poison control system. The electronic health records were queried for pediatric exposures to topical benzocaine treated at a healthcare facility from 2004 to 2014. Cases of benzocaine exposure were reviewed for demographic and clinical information, and descriptive statistical analysis was performed. The query resulted in 157 cases; 58 were excluded due to co-ingestants, or miscoding of non-benzocaine exposures. Children four years of age and younger represented the majority of cases (93%) with a median age of 1 year. There were 88 cases of accidental/ exploratory exposure, while 6 cases resulted from therapeutic application or error, 4 cases from adverse reactions, and 1 case from an unknown cause. Asymptomatic children accounted for 75.5% of cases, but major clinical effects were observed in 5 patients. Those with serious effects were exposed to a range of benzocaine concentrations (7.5-20%), with 4 cases reporting methemoglobin levels between 20.2%-55%. Methylene blue was administered in 4 of the cases exhibiting major effects. The majority of exposures were accidental ingestions by young children. Most exposures resulted in minor to no effects. However, some patients required treatment with methylene blue and admission to a critical care unit. Therapeutic application by parents or caregivers may lead to adverse effects from these commonly available products.

  8. Compatibility of automatic exposure control with new screen phosphors in diagnostic roentgenography

    International Nuclear Information System (INIS)

    Mulvaney, J.A.

    1982-01-01

    Automatic exposure control systems are used in diagnostic roentgenography to obtain proper film density for a variety of patient examinations and roentgenographic techniques. Most automatic exposure control systems have been designed for use with par speed, calcium tungstate intensifying screens. The use of screens with faster speeds and new phosphor materials has put extreme demands on present systems. The performance of a representative automatic exposure control system is investigated to determine its ability to maintain constant film density over a wide range of x-ray tube voltages and acrylic phantom thicknesses with four different intensifying screen phosphors. The effects of x-ray energy dependence, generator switching time and stored change are investigated. The system is able to maintain film density to within plus or minus 0.2 optical density units for techniques representing adult patients. A single nonadjustable tube voltage compensation circuit is adequate for the four different screen phosphors for x-ray tube voltages above sixty peak kilovolts. For techniques representing pediatric patients at high x-ray tube voltages, excess film density occurs due to stored charge in the transformer and high-voltage cables. An anticipation circuit in the automatic exposure control circuit can be modified to correct for stored charge effects. In a seperate experiment the energy dependence of three different ionization chamber detectors used in automatic exposure control systems is compared directly with the energy dependence of three different screen phosphors. The data on detector sensitivity and screen speed are combined to predict the best tube voltage compensation for each combination of screen and detector

  9. Pesticide Exposure and Head and Neck Cancers: A Case-Control Study in an Agricultural Region

    Directory of Open Access Journals (Sweden)

    Maryam Amizadeh

    2017-09-01

    Full Text Available Introduction: Causes of head and neck cancers (HNCs are multifactorial, and few studies have investigated the association between chemical exposure and HNCs. The objective of this study was to investigate associations between HNCs, agricultural occupations, and pesticide exposure. The potential for the accumulation of pesticides in the adipose tissue of patients was also investigated.   Materials and Methods: A structured questionnaire was used to collect information on demographics, occupation, and exposure to pesticides in a hospital-based case-control study. Pesticide residue in the adipose tissue of the neck in both cases and controls was also monitored via gas chromatography–mass spectroscopy.   Results: Thirty-one HNC cases were included in this study as well as 32 gender-, age-, and smoking-matched controls. An agricultural occupation was associated with HNC (odds ratio [OR], 3.26; 95% confidence interval [CI], 1.13–9.43 after controlling for age, sex, and smoking. Pesticide exposure was associated with total HNC cases (OR, 7.45; 95% CI, 1.78–3.07 and larynx cancer (OR, 9.33; 95% CI, 1.65–52.68. A dose-response pattern was observed for HNC cases (P=0.06 and larynx cancer (P=0.01. In tracing the pesticide residue, five chlorinated pesticides, namely dichlorodiphenyltrichloroethane (DDT, dichlorodipheny-ldichloroethane (DDD, dichlorodiphenyldichloroethylene (DDE, dieldrin, and lindane, were identified in the adipose tissue. Chlorinated pesticide detection was significantly associated with HNC (OR, 3.91; 95% CI 0.9–0.16.9.   Conclusion: HNCs were found to be associated with pesticide exposure after controlling for confounders. A high education level was identified as a modifying factor decreasing the risk of HNCs. Further studies with larger number of subjects are recommended to assess these relationships in greater detail.

  10. Blood harmane (1-methyl-9H-pyrido[3,4-b]indole) concentrations in essential tremor: repeat observation in cases and controls in New York.

    Science.gov (United States)

    Louis, Elan D; Jiang, Wendy; Gerbin, Marina; Viner, Amanda S; Factor-Litvak, Pam; Zheng, Wei

    2012-01-01

    Essential tremor (ET) is a widespread late-life neurological disease. Genetic and environmental factors are likely to play important etiological roles. Harmane (1-methyl-9H-pyrido[3,4-b]indole) is a potent tremor-producing neurotoxin. Previously, elevated blood harmane concentrations were demonstrated in ET cases compared to controls, but these observations have all been cross-sectional, assessing each subject at only one time point. Thus, no one has ever repeat-assayed blood harmane in the same subjects twice. Whether the observed case-control difference persists at a second time point, years later, is unknown. The current goal was to reassess a sample of our ET cases and controls to determine whether blood harmane concentration remained elevated in ET at a second time point. Blood harmane concentrations were quantified by a well-established high-performance liquid chromatography method in 63 ET cases and 70 controls. A mean of approximately 6 yr elapsed between the initial and this subsequent blood harmane determination. The mean log blood harmane concentration was significantly higher in cases than controls (0.30 ± 0.61 g(-10)/ml versus 0.08 ± 0.55 g(-10)/ml), and the median value in cases was double that of controls: 0.22 g(-10)/ml versus 0.11 g(-10)/ml. The log blood harmane concentration was highest in cases with a family history of ET. Blood harmane concentration was elevated in ET cases compared to controls when reassessed at a second time point several years later, indicating what seems to be a stable association between this environmental toxin and ET.

  11. The gene expression and immunohistochemical time-course of diphenylcyclopropenone-induced contact allergy in healthy humans following repeated epicutaneous challenges

    DEFF Research Database (Denmark)

    Mose, Kristian F; Burton, Mark; Thomassen, Mads

    2017-01-01

    DPCP challenges to find the predominant gene expression pattern, (ii) the time-course of cell infiltration following repeated DPCP challenges and (iii) the transcriptome of a repeated CA exposure model. We obtained punch biopsies from control and DPCP-exposed skin from ten DPCP sensitized individuals...

  12. Leptospira Exposure and Waste Pickers: A Case-Control Seroprevalence Study in Durango, Mexico.

    Science.gov (United States)

    Alvarado-Esquivel, Cosme; Hernandez-Tinoco, Jesus; Sanchez-Anguiano, Luis Francisco; Ramos-Nevarez, Agar; Cerrillo-Soto, Sandra Margarita; Guido-Arreola, Carlos Alberto

    2015-08-01

    Infection with Leptospira may occur by contact with Leptospira-infected animals. Waste pickers are in contact with rodents and dogs while picking in the garbage. Whether waste pickers are at risk for Leptospira infection is largely unknown. This study was aimed to determine the association of Leptospira IgG seroprevalence with the occupation of waste picking, and to determine the epidemiological characteristics of the waste pickers with Leptospira exposure. Through a case-control study, we determined the seroprevalence of anti-Leptospira IgG antibodies in 90 waste pickers and 90 age- and gender-matched control subjects in Durango City, Mexico using an enzyme immunoassay. Data were analyzed by bivariate and multivariate analyses. The prevalence of anti-Leptospira IgG antibodies was similar in waste pickers (4/90: 4.4%) to that in control subjects (5/90: 5.6%) (P = 1.00). Bivariate analysis showed that Leptospira exposure in waste pickers was associated with increasing age (P = 0.009), no education (P = 0.008), and consumption of rat meat (P = 0.04). However, these associations were no longer found by multivariate analysis. Leptospira exposure in waste pickers was not associated with health status, duration in the activity, wearing hand gloves and facemasks, history of injuries with sharp material of the garbage, or contact with animals or soil. This is the first study about Leptospira exposure in waste pickers. Results suggest that waste pickers are not at increasing risk for Leptospira exposure in Durango City, Mexico. Further research with a larger sample size to elucidate the association of Leptospira exposure with waste picking activity is needed.

  13. Leptospira Exposure and Waste Pickers: A Case-Control Seroprevalence Study in Durango, Mexico

    Science.gov (United States)

    Alvarado-Esquivel, Cosme; Hernandez-Tinoco, Jesus; Sanchez-Anguiano, Luis Francisco; Ramos-Nevarez, Agar; Cerrillo-Soto, Sandra Margarita; Guido-Arreola, Carlos Alberto

    2015-01-01

    Background Infection with Leptospira may occur by contact with Leptospira-infected animals. Waste pickers are in contact with rodents and dogs while picking in the garbage. Whether waste pickers are at risk for Leptospira infection is largely unknown. This study was aimed to determine the association of Leptospira IgG seroprevalence with the occupation of waste picking, and to determine the epidemiological characteristics of the waste pickers with Leptospira exposure. Methods Through a case-control study, we determined the seroprevalence of anti-Leptospira IgG antibodies in 90 waste pickers and 90 age- and gender-matched control subjects in Durango City, Mexico using an enzyme immunoassay. Data were analyzed by bivariate and multivariate analyses. Results The prevalence of anti-Leptospira IgG antibodies was similar in waste pickers (4/90: 4.4%) to that in control subjects (5/90: 5.6%) (P = 1.00). Bivariate analysis showed that Leptospira exposure in waste pickers was associated with increasing age (P = 0.009), no education (P = 0.008), and consumption of rat meat (P = 0.04). However, these associations were no longer found by multivariate analysis. Leptospira exposure in waste pickers was not associated with health status, duration in the activity, wearing hand gloves and facemasks, history of injuries with sharp material of the garbage, or contact with animals or soil. Conclusions This is the first study about Leptospira exposure in waste pickers. Results suggest that waste pickers are not at increasing risk for Leptospira exposure in Durango City, Mexico. Further research with a larger sample size to elucidate the association of Leptospira exposure with waste picking activity is needed. PMID:26124911

  14. Case-control study of congenital malformations and occupational exposure to low-level ionizing radiation

    International Nuclear Information System (INIS)

    Sever, L.E.; Gilbert, E.S.; Hessol, N.A.; McIntyre, J.M.

    1988-01-01

    In a case-control study, the authors investigated the association of parental occupational exposure to low-level external whole-body penetrating ionizing radiation and risk of congenital malformations in their offspring. Cases and controls were ascertained from births in two counties in southeastern Washington State, where the Hanford Site has been a major employer. A unique feature of this study was the linking of quantitative individual measurement of external whole-body penetrating ionizing radiation exposure of employees at the Hanford Site, using personal dosimeters, and the disease outcome, congenital malformations. The study population included 672 malformation cases and 977 matched controls from births occurring from 1957 through 1980. Twelve specific malformation types were analyzed for evidence of association with employment of the parents at Hanford and with occupational exposure to ionizing radiation. Two defects, congenital dislocation of the hip and tracheoesophageal fistula, showed statistically significant associations with employment of the parents at Hanford, but not with parental radiation exposure. Neural tube defects showed a significant association with parental preconception exposure, on the basis of a small number of cases. Eleven other defects, including Down syndrome, for which an association with radiation was considered most likely, showed no evidence of such an association. When all malformations were analyzed as a group, there was no evidence of an association with employment of the parents at Hanford, but the relation of parental exposure to radiation before conception was in the positive direction (one-tailed p value between 0.05 and 0.10). Given the number of statistical tests conducted, some or all of the observed positive correlations are likely to represent f