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Sample records for positive dose-response relationship

  1. Dose response relationship and Alara

    International Nuclear Information System (INIS)

    Hubert, P.

    1986-09-01

    In this paper, it will be shown how dose-response relationships allow to give quantitative figures for the detriment of irradiation. At this stage, the detriment is expressed directly as a certain number of health effects, whose valuation is not dealt with here. The present tools for quantifying, their weaknesses and their strenghts, and their scientific basis will be developed

  2. Dose-response relationship in clinical oncology

    International Nuclear Information System (INIS)

    Gehan, E.A.

    1984-01-01

    The relationship of dose (and dose rate) to response and toxicity in clinical oncology is reviewed. The concepts expressed by some authors in dose-response studies in animal and human systems are reviewed briefly. Dose rate and tactics of conducting clinical studies are reviewed for both radiotherapy and various types of chemotherapeutic treatment. Examples are given from clinical studies in Hodgkin's disease, acute leukemia, and breast cancer that may prove useful in planning future clinical studies

  3. The Dose Response Relationship for Radiation Carcinogenesis

    Science.gov (United States)

    Hall, Eric

    2008-03-01

    Recent surveys show that the collective population radiation dose from medical procedures in the U.S. has increased by 750% in the past two decades. It would be impossible to imagine the practice of medicine today without diagnostic and therapeutic radiology, but nevertheless the widespread and rapidly increasing use of a modality which is a known human carcinogen is a cause for concern. To assess the magnitude of the problem it is necessary to establish the shape of the dose response relationship for radiation carcinogenesis. Information on radiation carcinogenesis comes from the A-bomb survivors, from occupationally exposed individuals and from radiotherapy patients. The A-bomb survivor data indicates a linear relationship between dose and the risk of solid cancers up to a dose of about 2.5 Sv. The lowest dose at which there is a significant excess cancer risk is debatable, but it would appear to be between 40 and 100 mSv. Data from the occupation exposure of nuclear workers shows an excess cancer risk at an average dose of 19.4 mSv. At the other end of the dose scale, data on second cancers in radiotherapy patients indicates that cancer risk does not continue to rise as a linear function of dose, but tends towards a plateau of 40 to 60 Gy, delivered in a fractionated regime. These data can be used to estimate the impact of diagnostic radiology at the low dose end of the dose response relationship, and the impact of new radiotherapy modalities at the high end of the dose response relationship. In the case of diagnostic radiology about 90% of the collective population dose comes from procedures (principally CT scans) which involve doses at which there is credible evidence of an excess cancer incidence. While the risk to the individual is small and justified in a symptomatic patient, the same is not true of some screening procedures is asymptomatic individuals, and in any case the huge number of procedures must add up to a potential public health problem. In the

  4. Dose/response relationships and policy formulation

    International Nuclear Information System (INIS)

    Robinson, P.D.

    1981-01-01

    The ICRP 26 cost/benefit approach to establishing operational radiation protection guidelines is discussed. The purpose is to aid the policy maker in the decision making process, using as a basis the dose-response curve

  5. Positive inotropic and vasodilator actions of milrinone in patients with severe congestive heart failure. Dose-response relationships and comparison to nitroprusside.

    Science.gov (United States)

    Jaski, B E; Fifer, M A; Wright, R F; Braunwald, E; Colucci, W S

    1985-01-01

    Milrinone is a potent positive inotropic and vascular smooth muscle-relaxing agent in vitro, and therefore, it is not known to what extent each of these actions contributes to the drug's hemodynamic effects in patients with heart failure. In 11 patients with New York Heart Association class III or IV congestive heart failure, incremental intravenous doses of milrinone were administered to determine the dose-response relationships for heart rate, systemic vascular resistance, and inotropic state, the latter measured by peak positive left ventricular derivative of pressure with respect to time (dP/dt). To clarify further the role of a positive inotropic action, the relative effects of milrinone and nitroprusside on left ventricular stroke work and dP/dt were compared in each patient at doses matched to cause equivalent reductions in mean arterial pressure or systemic vascular resistance, indices of left ventricular afterload. Milrinone caused heart rate, stroke volume, and dP/dt to increase, and systemic vascular resistance to decrease in a concentration-related manner. At the two lowest milrinone doses resulting in serum concentrations of 63 +/- 4 and 156 +/- 5 ng/ml, respectively, milrinone caused significant increases in stroke volume and dP/dt, but no changes in systemic vascular resistance or heart rate. At the maximum milrinone dose administered (mean serum concentration, 427 +/- 11 ng/ml), heart rate increased from 92 +/- 4 to 99 +/- 4 bpm (P less than 0.01), mean aortic pressure fell from 82 +/- 3 to 71 +/- 3 mmHg (P less than 0.01), right atrial pressure fell from 15 +/- 2 to 7 +/- 1 mmHg (P less than 0.005), left ventricular end-diastolic pressure fell from 26 +/- 3 to 18 +/- 3 (P less than 0.005), stroke volume index increased from 20 +/- 2 to 30 +/- 2 ml/m2 (P less than 0.005), stroke work index increased from 14 +/- 2 to 21 +/- 2 g X m/m2 (P less than 0.01), and dP/dt increased from 858 +/- 54 to 1,130 +/- 108 mmHg/s (P less than 0.005). When compared

  6. Dose-response relationships for carcinogens: a review

    International Nuclear Information System (INIS)

    Zeise, L.; Wilson, R.; Crouch, E.A.C.

    1987-01-01

    The authors review the experimental evidence for various shapes of dose-response relationships for carcinogens and summarize those experiments that give the most information on relatively low doses. A brief review of some models is given to illustrate the shapes of dose-response curve expected from them. Their major interest is in the use of dose-response relationships to estimate risks to humans at low doses, and so they pay special attention to experimentally observed and theoretically expected nonlinearities. There are few experimental examples of nonlinear dose-response relations in humans, but this may simply be due to the limitations in the data. The several examples in rodents, even though for high dose data, suggest that nonlinearity is common. In some cases such nonlinearities may be rationalized on the basis of the pharmacokinetics of the test compound or its metabolites

  7. Confidence bounds for nonlinear dose-response relationships

    DEFF Research Database (Denmark)

    Baayen, C; Hougaard, P

    2015-01-01

    An important aim of drug trials is to characterize the dose-response relationship of a new compound. Such a relationship can often be described by a parametric (nonlinear) function that is monotone in dose. If such a model is fitted, it is useful to know the uncertainty of the fitted curve...... intervals for the dose-response curve. These confidence bounds have better coverage than Wald intervals and are more precise and generally faster than bootstrap methods. Moreover, if monotonicity is assumed, the profile likelihood approach takes this automatically into account. The approach is illustrated...

  8. Dose-response relationship with radiotherapy: an evidence?

    International Nuclear Information System (INIS)

    Chauvet, B.; Rauglaudre, G. de; Mineur, L.; Alfonsi, M.; Reboul, F.

    2003-01-01

    The dose-response relationship is a fundamental basis of radiobiology. Despite many clinical data, difficulties remain to demonstrate a relation between dose and local control: relative role of treatment associated with radiation therapy (surgery, chemotherapy, hormonal therapy), tumor heterogeneity, few prospective randomized studies, uncertainty of local control assessment. Three different situations are discussed: tumors with high local control probabilities for which dose effect is demonstrated by randomized studies (breast cancer) or sound retrospective data (soft tissues sarcomas), tumors with intermediate local control probabilities for which dose effect seems to be important according to retrospective studies and ongoing or published phase III trials (prostate cancer), tumors with low local control probabilities for which dose effect appears to be modest beyond standard doses, and inferior to the benefit of concurrent chemotherapy (lung and oesophageal cancer). For head and neck tumors, the dose-response relationship has been explored through hyperfractionation and accelerated radiation therapy and a dose effect has been demonstrated but must be compared to the benefit of concurrent chemotherapy. Last but not least, the development of conformal radiotherapy allow the exploration of the dose response relationship for tumors such as hepatocellular carcinomas traditionally excluded from the field of conventional radiation therapy. In conclusion, the dose-response relationship remains a sound basis of radiation therapy for many tumors and is a parameter to take into account for further randomized studies. (author)

  9. Radiation Dose-Response Relationships and Risk Assessment

    International Nuclear Information System (INIS)

    Strom, Daniel J.

    2005-01-01

    The notion of a dose-response relationship was probably invented shortly after the discovery of poisons, the invention of alcoholic beverages, and the bringing of fire into a confined space in the forgotten depths of ancient prehistory. The amount of poison or medicine ingested can easily be observed to affect the behavior, health, or sickness outcome. Threshold effects, such as death, could be easily understood for intoxicants, medicine, and poisons. As Paracelsus (1493-1541), the 'father' of modern toxicology said, 'It is the dose that makes the poison.' Perhaps less obvious is the fact that implicit in such dose-response relationships is also the notion of dose rate. Usually, the dose is administered fairly acutely, in a single injection, pill, or swallow; a few puffs on a pipe; or a meal of eating or drinking. The same amount of intoxicants, medicine, or poisons administered over a week or month might have little or no observable effect. Thus, before the discovery of ionizing radiation in the late 19th century, toxicology ('the science of poisons') and pharmacology had deeply ingrained notions of dose-response relationships. This chapter demonstrates that the notion of a dose-response relationship for ionizing radiation is hopelessly simplistic from a scientific standpoint. While useful from a policy or regulatory standpoint, dose-response relationships cannot possibly convey enough information to describe the problem from a quantitative view of radiation biology, nor can they address societal values. Three sections of this chapter address the concepts, observations, and theories that contribute to the scientific input to the practice of managing risks from exposure to ionizing radiation. The presentation begins with irradiation regimes, followed by responses to high and low doses of ionizing radiation, and a discussion of how all of this can inform radiation risk management. The knowledge that is really needed for prediction of individual risk is presented

  10. Dose response relationship in local radiotherapy for hepatocellular carcinoma

    International Nuclear Information System (INIS)

    Park, Hee Chul; Seong, Jin Sil; Han, Kwang Hyub; Chon, Chae Yoon; Moon, Young Myoung; Song, Jae Seok; Suh, Chang Ok

    2001-01-01

    In this study, it was investigated whether dose response relation existed or not in local radiotherapy for primary hepatocellular carcinoma. From January 1992 to March 2000, 158 patients were included in present study. Exclusion criteria included the presence of extrahepatic metastasis, liver cirrhosis of Child's class C, tumors occupying more than two thirds of the entire liver, and performance status on the ECOG scale of more than 3. Radiotherapy was given to the field including tumor with generous margin using 6, 10-MV X-ray. Mean tumor dose was 48.2±7.9 Gy in daily 1.8 Gy fractions. Tumor response was based on diagnostic radiologic examinations such as CT scan, MR imaging, hepatic artery angiography at 4-8 weeks following completion of treatment. Statistical analysis was done to investigate the existence of dose response relationship of local radiotherapy when it was applied to the treatment of primary hepatocellular carcinoma. An objective response was observed in 106 of 158 patients, giving a response rate of 67. 1%. Statistical analysis revealed that total dose was the most significant factor in relation to tumor response when local radiotherapy was applied to the treatment of primary hepatocellular carcinoma. Only 29.2% showed objective response in patients treated with dose less than 40 Gy, while 68.6% and 77.1 % showed major response in patients with 40-50 Gy and more than 50 Gy, respectively. Child-Pugh classification was significant factor in the development of ascites, overt radiation induced liver disease and gastroenteritis. Radiation dose was an important factor for development of radiation induced gastroduodenal ulcer. Present study showed the existence of dose response relationship in local radiotherapy for primary hepatocellular carcinoma. Only radiotherapy dose was a significant factor to predict the objective response. Further study is required to predict the maximal tolerance dose in consideration of liver function and non-irradiated liver

  11. Some hybrid models applicable to dose-response relationships

    International Nuclear Information System (INIS)

    Kumazawa, Shigeru

    1992-01-01

    A new type of models of dose-response relationships has been studied as an initial stage to explore a reliable extrapolation of the relationships decided by high dose data to the range of low dose covered by radiation protection. The approach is to use a 'hybrid scale' of linear and logarithmic scales; the first model is that the normalized surviving fraction (ρ S > 0) in a hybrid scale decreases linearly with dose in a linear scale, and the second is that the induction in a log scale increases linearly with the normalized dose (τ D > 0) in a hybrid scale. The hybrid scale may reflect an overall effectiveness of a complex system against adverse events caused by various agents. Some data of leukemia in the atomic bomb survivors and of rodent experiments were used to show the applicability of hybrid scale models. The results proved that proposed models fit these data not less than the popular linear-quadratic models, providing the possible interpretation of shapes of dose-response curves, e.g. shouldered survival curves varied by recovery time. (author)

  12. Dose response relationship in anti-stress gene regulatory networks.

    Science.gov (United States)

    Zhang, Qiang; Andersen, Melvin E

    2007-03-02

    To maintain a stable intracellular environment, cells utilize complex and specialized defense systems against a variety of external perturbations, such as electrophilic stress, heat shock, and hypoxia, etc. Irrespective of the type of stress, many adaptive mechanisms contributing to cellular homeostasis appear to operate through gene regulatory networks that are organized into negative feedback loops. In general, the degree of deviation of the controlled variables, such as electrophiles, misfolded proteins, and O2, is first detected by specialized sensor molecules, then the signal is transduced to specific transcription factors. Transcription factors can regulate the expression of a suite of anti-stress genes, many of which encode enzymes functioning to counteract the perturbed variables. The objective of this study was to explore, using control theory and computational approaches, the theoretical basis that underlies the steady-state dose response relationship between cellular stressors and intracellular biochemical species (controlled variables, transcription factors, and gene products) in these gene regulatory networks. Our work indicated that the shape of dose response curves (linear, superlinear, or sublinear) depends on changes in the specific values of local response coefficients (gains) distributed in the feedback loop. Multimerization of anti-stress enzymes and transcription factors into homodimers, homotrimers, or even higher-order multimers, play a significant role in maintaining robust homeostasis. Moreover, our simulation noted that dose response curves for the controlled variables can transition sequentially through four distinct phases as stressor level increases: initial superlinear with lesser control, superlinear more highly controlled, linear uncontrolled, and sublinear catastrophic. Each phase relies on specific gain-changing events that come into play as stressor level increases. The low-dose region is intrinsically nonlinear, and depending on

  13. Dose response relationship in anti-stress gene regulatory networks.

    Directory of Open Access Journals (Sweden)

    Qiang Zhang

    2007-03-01

    Full Text Available To maintain a stable intracellular environment, cells utilize complex and specialized defense systems against a variety of external perturbations, such as electrophilic stress, heat shock, and hypoxia, etc. Irrespective of the type of stress, many adaptive mechanisms contributing to cellular homeostasis appear to operate through gene regulatory networks that are organized into negative feedback loops. In general, the degree of deviation of the controlled variables, such as electrophiles, misfolded proteins, and O2, is first detected by specialized sensor molecules, then the signal is transduced to specific transcription factors. Transcription factors can regulate the expression of a suite of anti-stress genes, many of which encode enzymes functioning to counteract the perturbed variables. The objective of this study was to explore, using control theory and computational approaches, the theoretical basis that underlies the steady-state dose response relationship between cellular stressors and intracellular biochemical species (controlled variables, transcription factors, and gene products in these gene regulatory networks. Our work indicated that the shape of dose response curves (linear, superlinear, or sublinear depends on changes in the specific values of local response coefficients (gains distributed in the feedback loop. Multimerization of anti-stress enzymes and transcription factors into homodimers, homotrimers, or even higher-order multimers, play a significant role in maintaining robust homeostasis. Moreover, our simulation noted that dose response curves for the controlled variables can transition sequentially through four distinct phases as stressor level increases: initial superlinear with lesser control, superlinear more highly controlled, linear uncontrolled, and sublinear catastrophic. Each phase relies on specific gain-changing events that come into play as stressor level increases. The low-dose region is intrinsically nonlinear

  14. Dose-response relationships for radium-induced bone sarcomas

    International Nuclear Information System (INIS)

    Rowland, R.E.; Stehney, A.F.; Lucas, H.F. Jr.

    1981-01-01

    The incidence of bone sarcomas among 3055 female radium-dial workers who entered the dial industry before 1950 was used to determine dose-response relationships for the induction of bone sarcomas by radium. Two subpopulations were analyzed: all measured cases who survived at last five years after the start of employment and all cases who survived at least two years after first measurement. The first constituted a group based on year of entry; it contained 1468 women who experienced 42 bone sarcomas; the expected number was 0.4. The second comprised a group based on first measurement; it contained 1257 women who experienced 13 bone sarcomas; the expected number was 0.2. The dose-response function, I = (C + αD + #betta#D 2 )e/sup -#betta#D/, and simplifications of this general form, were fit to each data set. Two functions, I = (C + αD + #betta#D 2 )e/sup -#betta#D/ and I = (C + #betta#D 2 )e/sup -#betta#D/, fit the data for year of entry (p greater than or equal to 0.05); both these functions and I = (C + αD) fit the data for first measurement. The function I = (C + #betta#D 2 )e/sup -#betta#D/ was used to predict the number of bone sarcomas in all other pre-1950 radium cases (medical, laboratory, and other exposure); fewer were actually observed than the fit of this function to the female dial workers predicted

  15. The dose-response relationship for UV-tumorigenesis

    International Nuclear Information System (INIS)

    Gruijl, F.R. de.

    1982-01-01

    The main objective of the investigations was to extend the knowledge on experimental UV-carcinogenesis and to use the experimental results as guidelines for developing a dose-response model for UV-carcinogenesis. The animal experiments carried out were all long-term ones. It was decided that - in anticipation of the data to be obtained - a model for such an assessment should be developed using the experimental results available at the start of the present study (1977). This initial study is presented. The results of two animal experiments are presented, which show that UV radiation is capable of inducing a systemic effect that enhances the de novo formation of UV induced tumors. The results of the main experiment are presented. In this experiment groups of mice were subjected to daily exposure to a certain dose of UV radiation in order to find the dose-response relationship. The relation between the daily dose and the duration of the treatment till the appearance of tumors (for instance, as measured by the yield) was ascertained for tumors of different sizes. It appears that the growth of a tumor is dose-independent, and, therefore, only the initiation of a tumor is dose-dependent. Finally an experiment is presented in which it was measured that, if a mouse is subjected to daily UV exposure, the transmission of the epidermis in the shortwave UV region decreases continuously. This decrease is due to hyperplasia of the epidermis, i.e., thickening of the epidermis by an increase in the number of cells per unit surface area. (Auth.)

  16. Dose-response relationship in local radiotherapy for hepatocellular carcinoma

    International Nuclear Information System (INIS)

    Park, Hee Chul; Seong, Jinsil; Han, Kwang Hyub; Chon, Chae Yoon; Moon, Young Myoung; Suh, Chang Ok

    2002-01-01

    Purpose: Dose escalation using three-dimensional conformal radiotherapy (3D-CRT) is based on the hypothesis that increasing the dose can enhance tumor control. This study aimed to determine whether a dose-response relationship exists in local radiotherapy for primary hepatocellular carcinoma (HCC). Methods and Materials: One hundred fifty-eight patients were enrolled in the present study between January 1992 and March 2000. The exclusion criteria included the presence of an extrahepatic metastasis, liver cirrhosis of Child class C, tumors occupying more than two-thirds of the entire liver, and a performance status on the Eastern Cooperative Oncology Group scale of more than 3. Radiotherapy was given to the field, including the tumor, with generous margin using 6- or 10-MV X-rays. The mean radiation dose was 48.2 ± 7.9 Gy in daily 1.8-Gy fractions. The tumor response was assessed based on diagnostic radiologic examinations, including a computed tomography scan, magnetic resonance imaging, and hepatic artery angiography 4-8 weeks after the completion of treatment. Liver toxicity and gastrointestinal complications were evaluated. Results: An objective response was observed in 106 of 158 (67.1%) patients. Statistical analysis revealed that the total dose was the most significant factor associated with the tumor response. The response rates in patients treated with doses 50 Gy were 29.2%, 68.6%, and 77.1%, respectively. Survivals at 1 and 2 years after radiotherapy were 41.8% and 19.9%, respectively, with a median survival time of 10 months. The rate of liver toxicity according to the doses 50 Gy was 4.2%, 5.9%, and 8.4%, respectively, and the rate of gastrointestinal complications was 4.2%, 9.9%, and 13.2%, respectively. Conclusions: The present study showed the existence of a dose-response relationship in local radiotherapy for primary HCC. Only the radiation dose was a significant factor for predicting an objective response. The results of this study showed that 3D

  17. Optimal dose-response relationships in voice therapy.

    Science.gov (United States)

    Roy, Nelson

    2012-10-01

    Like other areas of speech-language pathology, the behavioural management of voice disorders lacks precision regarding optimal dose-response relationships. In voice therapy, dosing can presumably vary from no measurable effect (i.e., no observable benefit or adverse effect), to ideal dose (maximum benefit with no adverse effects), to doses that produce toxic or harmful effects on voice production. Practicing specific vocal exercises will inevitably increase vocal load. At ideal doses, these exercises may be non-toxic and beneficial, while at intermediate or high doses, the same exercises may actually be toxic or damaging to vocal fold tissues. In pharmacology, toxicity is a critical concept, yet it is rarely considered in voice therapy, with little known regarding "effective" concentrations of specific voice therapies vs "toxic" concentrations. The potential for vocal fold tissue damage related to overdosing on specific vocal exercises has been under-studied. In this commentary, the issue of dosing will be explored within the context of voice therapy, with particular emphasis placed on possible "overdosing".

  18. Chronic periodontitis and smoking. Prevalence and dose-response relationship.

    Science.gov (United States)

    Khan, Shahrukh; Khalid, Taimur; Awan, Kamran H

    2016-08-01

    To determine the prevalence and dose-response relationship of chronic periodontitis among smokers in Pakistan.   This is a cross-sectional study among participants seeking dental care in Karachi Medical and Dental College, Karachi, Pakistan. A total of 443 participants with a mean age of 44.3 (±6.5) participated in the study from April 2011 to December 2011. Males comprised 64.7%, and females comprised 35.2%. Participants were interviewed on social demographics and oral habits. Participants with shallow pockets (3.5-5.5 mm) and deep pockets (greater than 5.5 mm) were considered suffering from chronic periodontitis. The characteristics of participants were assessed using frequency distribution for categorical variables and mean (standard deviation) for continuous variables.  Among 443 participants, smokers were distributed as 55.1% and non-smokers as 44.9%. Smoking was found to be significantly related to young adults (p less than 0.007), male gender (p less than 0.001), and lower education level (p less than 0.01). Overall prevalence of chronic periodontitis among smokers was estimated at 81.6%. Heavy smoking was found to have significantly high prevalence (p less than 0.001) and severity (p less than 0.001) of periodontitis as compared with moderate and light smokers. The multivariate unadjusted model depicted 3.5 times higher risk of chronic periodontitis among smokers (p less than 0.001). Chronic periodontitis had a high prevalence among smokers. Heavy smoking was found to have a higher risk for having periodontitis.

  19. Dose-response relationships and threshold levels in skin and respiratory allergy

    NARCIS (Netherlands)

    Arts, J.H.E.; Mommers, C.; Heer, C.de

    2006-01-01

    A literature study was performed to evaluate dose-response relationships and no-effect levels for sensitization and elicitation in skin- and respiratory allergy. With respect to the skin, dose-response relationships and no-effect levels were found for both intradermal and topical induction, as well

  20. Non-monotonic dose-response relationships and endocrine disruptors: a qualitative method of assessment

    OpenAIRE

    Lagarde, Fabien; Beausoleil, Claire; Belcher, Scott M; Belzunces, Luc P; Emond, Claude; Guerbet, Michel; Rousselle, Christophe

    2015-01-01

    International audience; Experimental studies investigating the effects of endocrine disruptors frequently identify potential unconventional dose-response relationships called non-monotonic dose-response (NMDR) relationships. Standardized approaches for investigating NMDR relationships in a risk assessment context are missing. The aim of this work was to develop criteria for assessing the strength of NMDR relationships. A literature search was conducted to identify published studies that repor...

  1. Dose-response relationship in the treatment of gastrointestinal disorders.

    Science.gov (United States)

    Weihrauch, T R; Demol, P

    1989-08-01

    Numerous clinical studies have been performed to establish efficacy and safety of drugs in gastroenterological disorders. Only in a few if any of these studies, however, the rationale for the optimal dose and the dose regimens, respectively, have been addressed. Adequate and well-controlled dose finding studies play a key role in the clinical assessment of new drugs and in the evaluation of new indications. Hereby the range from the minimal effective dose to the maximal effective and well tolerated dose can be assessed and thus the optimal dose-range and dosage regimen be determined. Meaningful pharmacodynamic studies can be performed in the gastrointestinal tract also in healthy volunteers provided that a method with a high predictability for the desired therapeutic effect is available such as measurement of gastric acid secretion and its inhibition by a drug. Dose finding studies in gastroenterology can be carried out under two main aspects: First, to assess the pharmacodynamic and therapeutic effect of a compound on the gastrointestinal tract (e.g. anti-ulcer drug). Second, to evaluate the side effects of a drug on the gastrointestinal tract (e.g. gastric mucosal damage by non-steroidal anti-inflammatory drugs). For the evaluation of new drugs in gastrointestinal therapy a number of methods are available which yield accurate and reproducible data. While careful clinical-pharmacological dose-response studies using these methods have been carried out already more than a decade ago, it is surprising that therapeutic dose finding studies have become available only during the past few years. For scientific as well as for ethical reasons more trials which determine the optimal therapeutic dose are warranted.

  2. Radiation dose-response relationship of micronucleus occurrence in pollen mother cells of tradescantia

    International Nuclear Information System (INIS)

    Kim, Jin Kyu; Kim, Yeon Ku; Song, Hi Sup

    1999-01-01

    This study was carried out to investigate the radiation dose-response of micronucleus frequencies in Tradescantia pollen mother cells. The number of micronuclei increased in the tetrads as a result of chromosome deletion after irradiation. The maximal frequency of micronucleus showed a good dose-response relationship in the range of dose 0∼50 cGy. On the basis of the relationship, a dose of 1 cGy resulted in two additional micronuclei in 100 tetrads. The radiation dose-response relationship of micronucleus occurrence is prerequisite to biological monitoring of radiation and can be modified for biological risk assessment of toxicants, and to safety test of water or soil integrity

  3. Assessing dose-response relationships for endocrine disrupting chemicals (EDCs): a focus on non-monotonicity.

    Science.gov (United States)

    Zoeller, R Thomas; Vandenberg, Laura N

    2015-05-15

    The fundamental principle in regulatory toxicology is that all chemicals are toxic and that the severity of effect is proportional to the exposure level. An ancillary assumption is that there are no effects at exposures below the lowest observed adverse effect level (LOAEL), either because no effects exist or because they are not statistically resolvable, implying that they would not be adverse. Chemicals that interfere with hormones violate these principles in two important ways: dose-response relationships can be non-monotonic, which have been reported in hundreds of studies of endocrine disrupting chemicals (EDCs); and effects are often observed below the LOAEL, including all environmental epidemiological studies examining EDCs. In recognition of the importance of this issue, Lagarde et al. have published the first proposal to qualitatively assess non-monotonic dose response (NMDR) relationships for use in risk assessments. Their proposal represents a significant step forward in the evaluation of complex datasets for use in risk assessments. Here, we comment on three elements of the Lagarde proposal that we feel need to be assessed more critically and present our arguments: 1) the use of Klimisch scores to evaluate study quality, 2) the concept of evaluating study quality without topical experts' knowledge and opinions, and 3) the requirement of establishing the biological plausibility of an NMDR before consideration for use in risk assessment. We present evidence-based logical arguments that 1) the use of the Klimisch score should be abandoned for assessing study quality; 2) evaluating study quality requires experts in the specific field; and 3) an understanding of mechanisms should not be required to accept observable, statistically valid phenomena. It is our hope to contribute to the important and ongoing debate about the impact of NMDRs on risk assessment with positive suggestions.

  4. Quantitative radiation dose-response relationships for normal tissues in man - I. Gustatory tissues response during photon and neutron radiotherapy

    International Nuclear Information System (INIS)

    Mossman, K.L.

    1982-01-01

    Quantitative radiation dose-response curves for normal gustatory tissue in man were studied. Taste function, expressed as taste loss, was evaluated in 84 patients who were given either photon or neutron radiotherapy for tumors in the head and neck region. Patients were treated to average tumor doses of 6600 cGy (photon) or 2200 cGy intervals for photon patients and 320-cGy intervals for neutron patients during radiotherapy. The dose-response curves for photons and neutrons were analyzed by fitting a four-parameter logistic equation to the data. Photon and neutron curves differed principally in their relative position along the dose axis. Comparison of the dose-response curves were made by determination of RBE. At 320 cGy, the lowest neutron dose at which taste measurements were made, RBE = 5.7. If this RBE is correct, then the therapeutic gain factor may be equal to or less than 1, indicating no biological advantage in using neutrons over photons for this normal tissue. These studies suggest measurements of taste function and evaluation of dose-response relationships may also be useful in quantitatively evaluating the efficacy of chemical modifiers of radiation response such as hypoxic cell radiosensitizers and radioprotectors

  5. Dose-response relationships for environmentally mediated infectious disease transmission models.

    Directory of Open Access Journals (Sweden)

    Andrew F Brouwer

    2017-04-01

    Full Text Available Environmentally mediated infectious disease transmission models provide a mechanistic approach to examining environmental interventions for outbreaks, such as water treatment or surface decontamination. The shift from the classical SIR framework to one incorporating the environment requires codifying the relationship between exposure to environmental pathogens and infection, i.e. the dose-response relationship. Much of the work characterizing the functional forms of dose-response relationships has used statistical fit to experimental data. However, there has been little research examining the consequences of the choice of functional form in the context of transmission dynamics. To this end, we identify four properties of dose-response functions that should be considered when selecting a functional form: low-dose linearity, scalability, concavity, and whether it is a single-hit model. We find that i middle- and high-dose data do not constrain the low-dose response, and different dose-response forms that are equally plausible given the data can lead to significant differences in simulated outbreak dynamics; ii the choice of how to aggregate continuous exposure into discrete doses can impact the modeled force of infection; iii low-dose linear, concave functions allow the basic reproduction number to control global dynamics; and iv identifiability analysis offers a way to manage multiple sources of uncertainty and leverage environmental monitoring to make inference about infectivity. By applying an environmentally mediated infectious disease model to the 1993 Milwaukee Cryptosporidium outbreak, we demonstrate that environmental monitoring allows for inference regarding the infectivity of the pathogen and thus improves our ability to identify outbreak characteristics such as pathogen strain.

  6. Non-Linear Dose Response Relationships in Biology, Toxicology, and Medicine (June 8-10, 2004). Final Report

    International Nuclear Information System (INIS)

    Calabrese, Edward J.

    2004-01-01

    The conference attracts approximately 500 scientists researching in the area of non-linear low dose effects. These scientists represent a wide range of biological/medical fields and technical disciplines. Observations that biphasic dose responses are frequently reported in each of these areas but that the recognition of similar dose response relationships across disciplines is very rarely appreciated and exploited. By bringing scientist of such diverse backgrounds together who are working on the common area of non-linear dose response relationships this will enhance our understanding of the occurrence, origin, mechanism, significance and practical applications of such dose response relationships

  7. Concord Grape Juice Polyphenols and Cardiovascular Risk Factors: Dose-Response Relationships

    Science.gov (United States)

    Blumberg, Jeffrey B.; Vita, Joseph A.; Chen, C. -Y. Oliver

    2015-01-01

    Pure fruit juices provide nutritional value with evidence suggesting some of their benefits on biomarkers of cardiovascular disease risk may be derived from their constituent polyphenols, particularly flavonoids. However, few data from clinical trials are available on the dose-response relationship of fruit juice flavonoids to these outcomes. Utilizing the results of clinical trials testing single doses, we have analyzed data from studies of 100% Concord grape juice by placing its flavonoid content in the context of results from randomized clinical trials of other polyphenol-rich foods and beverages describing the same outcomes but covering a broader range of intake. We selected established biomarkers determined by similar methods for measuring flow-mediated vasodilation (FMD), blood pressure, platelet aggregation, and the resistance of low density lipoprotein cholesterol (LDL) to oxidation. Despite differences among the clinical trials in the treatment, subjects, and duration, correlations were observed between the dose and FMD. Inverse dose-response relationships, albeit with lower correlation coefficients, were also noted for the other outcomes. These results suggest a clear relationship between consumption of even modest serving sizes of Concord grape juice, flavonoid intake, and effects on risk factors for cardiovascular disease. This approach to dose-response relationships may prove useful for testing other individual foods and beverages. PMID:26633488

  8. Epidemiological methods for assessing dose-response and dose-effect relationships

    DEFF Research Database (Denmark)

    Kjellström, Tord; Grandjean, Philippe

    2007-01-01

    Selected Molecular Mechanisms of Metal Toxicity and Carcinogenicity General Considerations of Dose-Effect and Dose-Response Relationships Interactions in Metal Toxicology Epidemiological Methods for Assessing Dose-Response and Dose-Effect Relationships Essential Metals: Assessing Risks from Deficiency......Description Handbook of the Toxicology of Metals is the standard reference work for physicians, toxicologists and engineers in the field of environmental and occupational health. This new edition is a comprehensive review of the effects on biological systems from metallic elements...... access to a broad range of basic toxicological data and also gives a general introduction to the toxicology of metallic compounds. Audience Toxicologists, physicians, and engineers in the fields of environmental and occupational health as well as libraries in these disciplines. Will also be a useful...

  9. A meta-analysis on dose-response relationship between night shift work and the risk of breast cancer.

    Science.gov (United States)

    Wang, F; Yeung, K L; Chan, W C; Kwok, C C H; Leung, S L; Wu, C; Chan, E Y Y; Yu, I T S; Yang, X R; Tse, L A

    2013-11-01

    This study aimed to conduct a systematic review to sum up evidence of the associations between different aspects of night shift work and female breast cancer using a dose-response meta-analysis approach. We systematicly searched all cohort and case-control studies published in English on MEDLINE, Embase, PSYCInfo, APC Journal Club and Global Health, from January 1971 to May 2013. We extracted effect measures (relative risk, RR; odd ratio, OR; or hazard ratio, HR) from individual studies to generate pooled results using meta-analysis approaches. A log-linear dose-response regression model was used to evaluate the relationship between various indicators of exposure to night shift work and breast cancer risk. Downs and Black scale was applied to assess the methodological quality of included studies. Ten studies were included in the meta-analysis. A pooled adjusted relative risk for the association between 'ever exposed to night shift work' and breast cancer was 1.19 [95% confidence interval (CI) 1.05-1.35]. Further meta-analyses on dose-response relationship showed that every 5-year increase of exposure to night shift work would correspondingly enhance the risk of breast cancer of the female by 3% (pooled RR = 1.03, 95% CI 1.01-1.05; Pheterogeneity night shifts would result in a 13% (RR = 1.13, 95% CI 1.07-1.21; Pheterogeneity = 0.06) increase in breast cancer risk. This systematic review updated the evidence that a positive dose-response relationship is likely to present for breast cancer with increasing years of employment and cumulative shifts involved in the work.

  10. A biological basis for the linear non-threshold dose-response relationship for low-level carcinogen exposure

    International Nuclear Information System (INIS)

    Albert, R.E.

    1981-01-01

    This chapter examines low-level dose-response relationships in terms of the two-stage mouse tumorigenesis model. Analyzes the feasibility of the linear non-threshold dose-response model which was first adopted for use in the assessment of cancer risks from ionizing radiation and more recently from chemical carcinogens. Finds that both the interaction of B(a)P with epidermal DNA of the mouse skin and the dose-response relationship for the initiation stage of mouse skin tumorigenesis showed a linear non-threshold dose-response relationship. Concludes that low level exposure to environmental carcinogens has a linear non-threshold dose-response relationship with the carcinogen acting as an initiator and the promoting action being supplied by the factors that are responsible for the background cancer rate in the target tissue

  11. Continuous dose-response relationship of the LDL-cholesterol-lowering effect of phytosterol intake.

    Science.gov (United States)

    Demonty, Isabelle; Ras, Rouyanne T; van der Knaap, Henk C M; Duchateau, Guus S M J E; Meijer, Linsie; Zock, Peter L; Geleijnse, Johanna M; Trautwein, Elke A

    2009-02-01

    Phytosterols (plant sterols and stanols) are well known for their LDL-cholesterol (LDL-C)-lowering effect. A meta-analysis of randomized controlled trials in adults was performed to establish a continuous dose-response relationship that would allow predicting the LDL-C-lowering efficacy of different phytosterol doses. Eighty-four trials including 141 trial arms were included. A nonlinear equation comprising 2 parameters (the maximal LDL-C lowering and an incremental dose step) was used to describe the dose-response curve. The overall pooled absolute (mmol/L) and relative (%) LDL-C-lowering effects of phytosterols were also assessed with a random effects model. The pooled LDL-C reduction was 0.34 mmol/L (95% CI: -0.36, -0.31) or 8.8% (95% CI: -9.4, -8.3) for a mean daily dose of 2.15 g phytosterols. The impacts of subject baseline characteristics, food formats, type of phytosterols, and study quality on the continuous dose-response curve were determined by regression or subgroup analyses. Higher baseline LDL-C concentrations resulted in greater absolute LDL-C reductions. No significant differences were found between dose-response curves established for plant sterols vs. stanols, fat-based vs. non fat-based food formats and dairy vs. nondairy foods. A larger effect was observed with solid foods than with liquid foods only at high phytosterol doses (>2 g/d). There was a strong tendency (P = 0.054) towards a slightly lower efficacy of single vs. multiple daily intakes of phytosterols. In conclusion, the dose-dependent LDL-C-lowering efficacy of phytosterols incorporated in various food formats was confirmed and equations of the continuous relationship were established to predict the effect of a given phytosterol dose. Further investigations are warranted to investigate the impact of solid vs. liquid food formats and frequency of intake on phytosterol efficacy.

  12. Demonstration of brachytherapy boost dose-response relationships in glioblastoma multiforme

    International Nuclear Information System (INIS)

    Sneed, Penny K.; Lamborn, Kathleen R.; Larson, David A.; Prados, Michael D.; Malec, Mary K.; McDermott, Michael W.; Weaver, Keith A.; Phillips, Theodore L.; Wara, William M.; Gutin, Philip H.

    1996-01-01

    Purpose: To evaluate brachytherapy dose-response relationships in adults with glioblastoma undergoing temporary 125 I implant boost after external beam radiotherapy. Methods and Materials: Since June 1987, orthogonal radiographs using a fiducial marker box have been used to verify brain implant source positions and generate dose-volume histograms at the University of California, San Francisco. For adults who underwent brachytherapy boost for glioblastoma from June 1987 through December 1992, tumor volumes were reoutlined to ensure consistency and dose-volume histograms were recalculated. Univariate and multivariate analyses of various patient and treatment parameters were performed evaluating for influence of dose on freedom from local failure (FFLF) and actuarial survival. Results: Of 102 implant boosts, 5 were excluded because computer plans were unavailable. For the remaining 97 patients, analyses with adjustment for known prognostic factors (age, KPS, extent of initial surgical resection) and prognostic factors identified on univariate testing (adjuvant chemotherapy) showed that higher minimum brachytherapy tumor dose was strongly associated with improved FFLF (p = 0.001). A quadratic relationship was found between total biological effective dose and survival, with a trend toward optimal survival probability at 47 Gy minimum brachytherapy tumor dose (corresponding to about 65 Gy to 95% of the tumor volume); survival decreased with lower or higher doses. Two patients expired and one requires hospice care because of brain necrosis after brachytherapy doses > 63 Gy to 95% of the tumor volume with 60 Gy to > 18 cm 3 of normal brain. Conclusion: Although higher minimum brachytherapy tumor dose was strongly associated with better local control, a brachytherapy boost dose > 50-60 Gy may result in life-threatening necrosis. We recommend careful conformation of the prescription isodose line to the contrast enhancing tumor volume, delivery of a minimum brachytherapy

  13. Dose-response relationship between periodontal inflamed surface area and HbA1c in type 2 Diabetics

    NARCIS (Netherlands)

    Nesse, Willem; Linde, Annemiek; Abbas, Frank; Spijkervet, Frederik Karst Lucien; Dijkstra, Pieter Ubele; de Brabander, Eric Carl; Gerstenbluth, Izzy; Vissink, Arjan

    Nesse W, Linde A, Abbas F, Spijkervet FKL, Dijkstra PU, de Brabander EC, Gerstenbluth I, Vissink A. Dose-response relationship between periodontal inflamed surface area and HbA1c in type 2 diabetics. J Clin Periodontol 2009; 36: 295-300. doi: 10.1111/j.1600-051X.2009.01377.x. A dose-response

  14. Effect of heterogeneity of human population in cell radiosensitivity on the extrapolation of dose-response relationships to low doses

    International Nuclear Information System (INIS)

    Filyushkin, I.V.; Bragin, Yu.N.; Khandogina, E.K.

    1989-01-01

    Presented are the results of an investigation of the dose-response relationship for the yield of chromosome aberrations in peripheral blood lymphocytes of persons with some hereditary diseases which represent the high risk group with respect to the increased incidence of malignant tumors and decreased life span. Despite substantially different absolute radiosensitivities of chromosomes, the variations of the alpha/beta ratio determining the extrapolation of experimental dose-response relationships to low doses did not prove to be too high, the mean deviation from the control being 15%. This points to the possible practical use of the dose-response relationships averaged over the human population as a whole

  15. Defining a dose-response relationship with radiotherapy for prostate cancer: is more really better?

    International Nuclear Information System (INIS)

    Vicini, Frank A.; Abner, Anthony; Baglan, Kathy L.; Kestin, Larry L.; Martinez, Alvaro A.

    2001-01-01

    Purpose: Data were reviewed addressing the association between radiation therapy (RT) dose and treatment outcome for localized prostate cancer to help clarify the existence of a potential dose-response relationship. Methods and Materials: Articles were identified through the MEDLINE database, CancerLit database, and reference lists of relevant articles. Studies were categorized into four groups based upon the endpoint analyzed, including biochemical control (BC), local control (LC), pathologic control (PC), and cause-specific survival (CSS). The impact of increasing RT dose with each endpoint was recorded. Results: Twenty-two trials involving a total of 11,297 patients were identified. Of the 11 trials addressing the association of RT dose with LC, 9 showed statistically significant improvements. Of the 12 trials that reported BC with RT dose, all showed statistically significant improvements. Two out of 4 studies analyzing PC with increasing dose showed a positive correlation. Finally, 3 out of 9 studies addressing RT dose with CSS showed statistically significant improvements. Despite inconclusive results, patients with poor risk features (e.g., prostate-specific antigen [PSA] ≥10, Gleason score [GS] ≥7, or tumor stage ≥T2b) were most likely to benefit from increasing dose with respect to each endpoint. However, the optimal RT dose and the magnitude of benefit of dose escalation could not be identified. Conclusions: Although RT dose appears to correlate with various measures of treatment outcome, objective, high-quality data addressing this critical issue are still lacking. At the present time, the absolute improvement in outcome due to dose escalation, the subset of patients benefiting most, and the optimal dose remain to be defined

  16. Dose-response relationships of propranolol in Chinese subjects with different CYP2D6 genotypes.

    Science.gov (United States)

    Huang, Chin-Wei; Lai, Ming-Liang; Lin, Min-Shung; Lee, Hwei-Ling; Huang, Jin-Ding

    2003-01-01

    For clinical treatment, a smaller dosage of propranolol is often used among Chinese people. Propranolol is metabolized by polymorphic CYP2D6. We postulate that the lower propranolol dosage in Chinese is due to a slower CYP2D6 metabolism. A majority of the Chinese population has the nucleotide T188 in the CYP2D6 gene (CYP2D6*10) instead of C188 (CYP2D6*1), which most white subjects have. Chinese subjects of different CYP2D6*1/CYP2D6*10 genotypes have been shown to have different propranolol pharmacokinetic characteristics. In this study, we compared the beta-blockade effects of propranolol in Chinese subjects of the two different CYP2D6 genotypes. Based on the nucleotide 188 genotypes, two groups of 10 healthy subjects each were selected. Each subject was given a 10-, 20-, or 40-mg rac-propranolol tablet three times a day for 3 days in 3 different phases. Heart rate and blood pressure were measured in both supine and upright positions. The heart rate was also determined during treadmill exercise test. Plasma concentration of S-propranolol at 2 hrs after the last-dose administration was measured. Despite therebeing higher S-propranolol plasma concentration in CYP2D6*10 subjects than in CYP2D6*1 subjects at 10- and 20-mg dosage, the dose-response relationship was not significantly different in these subjects. Our results do not support the hypothesis that CYP2D6*1/CYP2D6*10 polymorphism may affect the beta-blockade effect of propranolol in Chinese subjects.

  17. The scientific basis for the establishment of threshold levels and dose response relationships of carcinogenesis

    International Nuclear Information System (INIS)

    1975-01-01

    The International Atomic Energy Agency hosted a two day Symposium from 2-3 December 1974 at its Headquarters, organized by the 'International Academy for Environmental Safety and the Forum fur Wissenschaft, Wirtschaft und Politik' on the subject 'Scientific Basis for the Establishment of Threshold. Levels and Dose Response Relationships of Carcinogenesis'. Following an introductory paper by the Radiation Biology Section of the Agency on 'Radiation Carcinogenesis - Dose Response Relationship, Threshold and Risk Estimates', a series of papers dealt with this problem in chemical carcinogenesis.It was suggested that more experiments should be done using non-human primates for tests of carcinogens, especially chemicals. Preliminary experiments using monkeys with a potent carcinogen - nitrosoamine - indicate that there could possibly be a dose where no effect can be observed during the 5 year period of study. It was also pointed out that the overall cost/benefit and risk/ benefit relationships should be taken into consideration in determining limits for chemicals which are potentially carcinogenic but are used routinely by the public and industries; these considerations have been weighed in setting exposure limits for radiation

  18. A threshold in the dose-response relationship for X-ray induced somatic mutation frequency in drosophila melanogaster

    International Nuclear Information System (INIS)

    Koana, Takao; Sakai, Kazuo; Okada, M.O.

    2004-01-01

    The dose-response relationship of ionizing radiation and its stochastic effects has been thought to be linear without any thresholds for a long time. The basic data for this model was obtained from mutational assays using germ cells of male fruit fly Drosophila melanogaster. However, cancer-causing activity should be examined more appropriately in somatic cells than in germ cells. In this paper, we examined the dose-response relationship of X-ray irradiation and somatic mutation in drosophila, and found a threshold at approximately 1 Gy in the DNA repair proficient flies. In the repair deficient siblings, the threshold was smaller and the inclination of the dose-response curve was five times steeper. These results suggest that the dose-response relationship between X-ray irradiation and somatic mutation has a threshold, and that the DNA repair function contributes to its formation. (author)

  19. Dose-response relationship for elective neck irradiation of head and neck cancer - facts and controversies

    International Nuclear Information System (INIS)

    Suwinski, R.; Maciejewski, B.; Withers, H.R.

    1998-01-01

    The aim of this study is to assign dose-response relationship for subclinical neck metastases of squamous cell head and neck cancer based on extensive survey of 24 data sets collected from the literature. Neck relapse rates (NRR) without and after elective (ENI) or preoperative irradiation were estimated for each site and stage of primary tumor and the reduction in neck relapse rate was calculated. An average NRR without ENI was 22% (12-35% ) and only 2.5% (0-1 0%) after the ENI with total dose of 46- 50 Gy which gives high reduction rate in the risk of neck recurrences being on the average 89% and 42% (0-46%) after preoperative irradiation using 22-30 Gy. Dose response curve for elective and preoperative irradiation have shown that 50 Gy in 2 Gy fraction reduces the incidence of neck relapses in the NO patients by more than 90% and only by less than 50% after total doses lower than 30 Gy. No correlation between the risk of neck metastases without ENI and the reduction in neck relapses after ENI was found. (authors)

  20. [Dose-response relationship of ropivacaine for epidural block in early herpes zoster guided by CT].

    Science.gov (United States)

    Xie, K Y; Ma, J B; Xu, Q; Huang, B; Yao, M; Ni, H D; Deng, J J; Chen, G D

    2017-12-26

    Objective: To determine the dose-response relationship of ropivacaine for epidural block in early herpes zoster by CT guided. Methods: From January 2015 to February 2017, according to the principle of completely random digital table, 80 patients with early herpes zoster who were prepared for epidural block were divided into 4 groups(each group 20 patients): in group A the concentration of ropivacaine was 0.08%, in group B was 0.10%, in group C was 0.12% and in group D was 0.14%.Under CT guidance, epidural puncture was performed in the relevant section, mixing liquid 5.0 ml (with 10% iodohydrin)were injected into epidural gap.CT scan showed that the mixing liquid covered the relevant spinal nerve segmental.The numeric rating scale(NRS) values before treatment and at 30 minutes, the incidence of adverse reactions were recorded, and the treatment were evaluated. The response to ropivacaine for epidural block in early herpes zoster was defined as positive when the NRS values was less than or equal to one.The ED(50), ED(95) and 95% confidence interval ( CI ) of ropivacaine for epidural block in early herpes zoster guided by CT were calculated by probit analysis. Results: The NRS values before treatment were 5.00(4.00, 6.00), 5.00(4.25, 6.00), 5.50(5.00, 6.00) and 5.00(4.00, 6.00), the difference was no significant( Z =2.576, P =0.462). The NRS values at 30 minutes decreased and the effective rate of the treatment increased(χ(2)=8.371, P =0.004), following ropivacaine dose gradient increasing, they were 1.50(1.00, 2.00), 1.00(1.00, 2.00), 0.50(0.00, 1.00) and 0.00(0.00, 1.00), the difference was statistically significant ( Z =17.421, P =0.001). There was one case in group C and four cases in group D were hypoesthesia, others were no significant adverse reactions occurred. The ED(50) and ED(95) (95% CI ) of ropivacaine for epidural block in early herpes zoster guided by CT were 0.078%(0.015%-0.095%)and 0.157%(0.133%-0.271%), respectively. Conclusion: Ropivacaine for

  1. The dose-response relationship between in-ear occupational noise exposure and hearing loss.

    Science.gov (United States)

    Rabinowitz, Peter M; Galusha, Deron; Dixon-Ernst, Christine; Clougherty, Jane E; Neitzel, Richard L

    2013-10-01

    Current understanding of the dose-response relationship between occupational noise and hearing loss is based on cross-sectional studies prior to the widespread use of hearing protection, and with limited data regarding noise exposures below 85 dBA. We report on the hearing loss experience of a unique cohort of industrial workers, with daily monitoring of noise inside of hearing protection devices. At an industrial facility, workers exhibiting accelerated hearing loss were enrolled in a mandatory programme to monitor daily noise exposures inside of hearing protection. We compared these noise measurements (as time-weighted LAVG) to interval rates of high-frequency hearing loss over a 6-year period using a mixed-effects model, adjusting for potential confounders. Workers' high-frequency hearing levels at study inception averaged more than 40 dB Hearing threshold level (HTL). Most noise exposures were less than 85 dBA (mean LAVG 76 dBA, IQR 74-80 dBA). We found no statistical relationship between LAvg and high-frequency hearing loss (p=0.53). Using a metric for monthly maximum noise exposure did not improve model fit. At-ear noise exposures below 85 dBA did not show an association with risk of high-frequency hearing loss among workers with substantial past noise exposure and hearing loss at baseline. Therefore, effective noise control to below 85 dBA may lead to significant reduction in occupational hearing loss risk in such individuals. Further research is needed on the dose-response relationship of noise and hearing loss in individuals with normal hearing and little prior noise exposure.

  2. The Dose Response Relationship between In Ear Occupational Noise Exposure and Hearing Loss

    Science.gov (United States)

    Rabinowitz, Peter M.; Galusha, Deron; Dixon-Ernst, Christine; Clougherty, Jane E.; Neitzel, Richard L.

    2014-01-01

    Objectives Current understanding of the dose-response relationship between occupational noise and hearing loss is based on cross-sectional studies prior to the widespread use hearing protection and with limited data regarding noise exposures below 85dBA. We report on the hearing loss experience of a unique cohort of industrial workers with daily monitoring of noise inside of hearing protection devices. Methods At an industrial facility, workers exhibiting accelerated hearing loss were enrolled in a mandatory program to monitor daily noise exposures inside of hearing protection. We compared these noise measurements (as time-weighted LAVG) to interval rates of high frequency hearing loss over a six year period using a mixed effects model, adjusting for potential confounders. Results Workers’ high frequency hearing levels at study inception averaged more than 40 dB hearing threshold level (HTL). Most noise exposures were less than 85dBA (mean LAVG 76 dBA, interquartile range 74 to 80 dBA). We found no statistical relationship between LAvg and high frequency hearing loss (p = 0.53). Using a metric for monthly maximum noise exposure did not improve model fit. Conclusion At-ear noise exposures below 85dBA did not show an association with risk of high frequency hearing loss among workers with substantial past noise exposure and hearing loss at baseline. Therefore, effective noise control to below 85dBA may lead to significant reduction in occupational hearing loss risk in such individuals. Further research is needed on the dose response relationship of noise and hearing loss in individuals with normal hearing and little prior noise exposure. PMID:23825197

  3. Mass shootings: a meta-analysis of the dose-response relationship.

    Science.gov (United States)

    Wilson, Laura C

    2014-12-01

    A meta-analysis was conducted to examine the dose-response theory as it relates to posttraumatic stress symptoms (PTSSs) following mass shootings. It was hypothesized that greater exposure to a mass shooting would be associated with greater PTSSs. Trauma exposure in the current study was broadly defined as the extent to which a person experienced or learned about a mass shooting. The meta-analysis identified 11 qualifying studies that included 13 independent effect sizes from a total of 8,047 participants. The overall weighted mean effect size, based on a random effects model, was r = .19, p shooting on the relationship between exposure and PTSSs. Because so few studies satisfied the inclusion criteria, the present study also documents that this area of the literature is underresearched. Copyright © 2014 International Society for Traumatic Stress Studies.

  4. Dose-response relationship for breast cancer induction at radiotherapy dose

    Directory of Open Access Journals (Sweden)

    Gruber Günther

    2011-06-01

    Full Text Available Abstract Purpose Cancer induction after radiation therapy is known as a severe side effect. It is therefore of interest to predict the probability of second cancer appearance for the patient to be treated including breast cancer. Materials and methods In this work a dose-response relationship for breast cancer is derived based on (i the analysis of breast cancer induction after Hodgkin's disease, (ii a cancer risk model developed for high doses including fractionation based on the linear quadratic model, and (iii the reconstruction of treatment plans for Hodgkin's patients treated with radiotherapy, (iv the breast cancer induction of the A-bomb survivor data. Results The fitted model parameters for an α/β = 3 Gy were α = 0.067Gy-1 and R = 0.62. The risk for breast cancer is according to this model for small doses consistent with the finding of the A-bomb survivors, has a maximum at doses of around 20 Gy and drops off only slightly at larger doses. The predicted EAR for breast cancer after radiotherapy of Hodgkin's disease is 11.7/10000PY which can be compared to the findings of several epidemiological studies where EAR for breast cancer varies between 10.5 and 29.4/10000PY. The model was used to predict the impact of the reduction of radiation volume on breast cancer risk. It was estimated that mantle field irradiation is associated with a 3.2-fold increased risk compared with mediastinal irradiation alone, which is in agreement with a published value of 2.7. It was also shown that the modelled age dependency of breast cancer risk is in satisfying agreement with published data. Conclusions The dose-response relationship obtained in this report can be used for the prediction of radiation induced secondary breast cancer of radiotherapy patients.

  5. A method to adjust radiation dose-response relationships for clinical risk factors

    DEFF Research Database (Denmark)

    Appelt, Ane Lindegaard; Vogelius, Ivan R

    2012-01-01

    Several clinical risk factors for radiation induced toxicity have been identified in the literature. Here, we present a method to quantify the effect of clinical risk factors on radiation dose-response curves and apply the method to adjust the dose-response for radiation pneumonitis for patients...

  6. European Academy of Allergy and Clinical Immunology task force report on 'dose-response relationship in allergen-specific immunotherapy'.

    Science.gov (United States)

    Calderón, M A; Larenas, D; Kleine-Tebbe, J; Jacobsen, L; Passalacqua, G; Eng, P A; Varga, E M; Valovirta, E; Moreno, C; Malling, H J; Alvarez-Cuesta, E; Durham, S; Demoly, P

    2011-10-01

    For a century, allergen-specific immunotherapy (SIT) has proven to be an effective treatment for allergic rhinitis, asthma, and insect sting allergy. However, as allergen doses are frequently adapted to the individual patient, there are few data on dose-response relationship in SIT. Allergen products for SIT are being increasingly required to conform to regulatory requirements for human medicines, which include the need to demonstrate dose-dependent effects. This report, produced by a Task Force of the EAACI Immunotherapy Interest Group, evaluates the currently available data on dose-response relationships in SIT and aims to provide recommendations for the design of future studies. Fifteen dose-ranging studies fulfilled the inclusion criteria and twelve reported a dose-response relationship for clinical efficacy. Several studies also reported a dose-response relationship for immunological and safety endpoints. Due to the use of different reference materials and methodologies for the determination of allergen content, variations in study design, and choice of endpoints, no comparisons could be made between studies and, as a consequence, no general dosing recommendations can be made. Despite recently introduced guidelines on the standardization of allergen preparations and study design, the Task Force identified a need for universally accepted standards for the measurement of allergen content in SIT preparations, dosing protocols, and selection of clinical endpoints to enable dose-response effects to be compared across studies. © 2011 John Wiley & Sons A/S.

  7. Dose - response relationship between noise exposure and the risk of occupational injury

    Directory of Open Access Journals (Sweden)

    Jin-Ha Yoon

    2015-01-01

    Full Text Available Many workers worldwide experience fatality and disability caused by occupational injuries. This study examined the relationship between noise exposure and occupational injuries at factories in Korea. A total of 1790 factories located in northern Gyeonggi Province, Korea was evaluated. The time-weighted average levels of dust and noise exposure were taken from Workplace Exposure Assessment data. Apart occupational injuries, sports events, traffic accidents, and other accidents occurring outside workplaces were excluded. The incidences of occupational injury in each factory were calculated by data from the Korea Workers′ Compensation and Welfare Services. Workplaces were classified according to the incidence of any occupational injuries (incident or nonincident workplaces, respectively. Workplace dust exposure was classified as 90 dB. Workplaces with high noise exposure were significantly associated with being incident workplaces, whereas workplaces with high dust exposure were not. The odds ratios (95% confidence intervals derived from a logistic regression model were 1.68 (1.27-2.24 and 3.42 (2.26-5.17 at 80-89 dB and ≥90 dB versus <80 dB. These associations remained significant when in a separate analysis according to high or low dust exposure level. Noise exposure increases the risk of occupational injury in the workplace. Furthermore, the risk of occupational injury increases with noise exposure level in a dose-response relationship. Therefore, strategies for reducing noise exposure level are required to decrease the risk of occupational injury.

  8. Dose-response relationships for chromosome aberrations in peripheral blood lymphocytes after whole- and partial-body irradiations. Pt. 1

    International Nuclear Information System (INIS)

    Liniecki, J.; Bajerska, A.; Wyszynska, K.

    1983-01-01

    Dose-response relationships were established for yield of dicentrics and for a fraction of damaged metaphases in lymphocytes after γ-irradiation of rabbits' whole blood in vitro. These relationships were based on the scoring of cells only in their first post-stimulation division and they served as a reference system for comparison with results of 60 Co γ-irradiation in vivo, either of the whole or of predetermined parts of an animal's body. There was a statistically acceptable agreement between dose-response data established for dicentric yield after whole-body irradiation in vivo and the reference dose-response curve derived from exposure of rabbit's blood in vitro. For partial-body (1/2) irradiations there was a satisfactory agreement between the dose-response curves in vitro for dicentric yield and fraction of metaphases damaged on the one hand and the response in vivo when the latter was related to mean doses to circulating blood. However, there was a drastic disagreement with the dose responses in vitro when measured cytogenetic quantities were plotted versus mean doses to body mass. When the latter were substituted for by comparable doses to circulating blood the in vivo-in vitro agreement was acceptable after irradiation. (orig.)

  9. Generation of dose-response relationships to assess the effects of acidity in precipitation on growth and productivity of vegetation

    International Nuclear Information System (INIS)

    Evans, L.S.

    1981-01-01

    Experiments were performed with several plant species in natural environments as well in a greenhouse and/or tissue culture facilities to establish dose-response functions of plant responses to simulated acidic rain in order to determine environmental risk assessments to ambient levels of acidic rain. Response functions of foliar injury, biomass of leaves and seed of soybean and pinto beans, root yields of radishes and garden beets, and reproduction of bracken fern are considered. The dose-response function of soybean seed yields with the hydrogen ion concentration of simulated acidic rainfalls was expressed by the equation y = 21.06-1.01 log x where y = seed yield in grams per plant and x = the hydrogen concentration if μeq l -1 . The correlation coefficient of this relationship was -0.90. A similar dose-response function was generated for percent fertilization of ferns in a forest understory. When percent fertilization is plotted on logarithmic scale with hydrogen ion concentration of the simulated rain solution, the Y intercept is 51.18, slope -0.041 with a correlation coefficient of -0.98. Other dose-response functions were generated that assist in a general knowledge as to which plant species and which physiological processes are most impacted by acidic precipitation. Some responses did not produce convenient dose-response relationships. In such cases the responses may be altered by other environmental factors or there may be no differences among treatment means

  10. Respiratory dysfunction in swine production facility workers: dose-response relationships of environmental exposures and pulmonary function.

    Science.gov (United States)

    Donham, K J; Reynolds, S J; Whitten, P; Merchant, J A; Burmeister, L; Popendorf, W J

    1995-03-01

    Human respiratory health hazards for people working in livestock confinement buildings have been recognized since 1974. However, before comprehensive control programs can be implemented, more knowledge is needed of specific hazardous substances present in the air of these buildings, and at what concentrations they are harmful. Therefore, a medical epidemiological and exposure-response study was conducted on 207 swine producers using intensive housing systems (108 farms). Dose-response relationships between pulmonary function and exposures are reported here. Positive correlations were seen between change in pulmonary function over a work period and exposure to total dust, respirable dust, ammonia, respirable endotoxin, and the interactions of age-of-producer and dust exposure and years-of-working-in-the-facility and dust exposure. Relationships between baseline pulmonary function and exposures were not strong and therefore, not pursued in this study. The correlations between exposure and response were stronger after 6 years of exposure. Multiple regression models were used to identify total dust and ammonia as the two primary environmental predictors of pulmonary function decrements over a work period. The regression models were then used to determine exposure concentrations related to pulmonary function decrements suggestive of a health hazard. Total dust concentrations > or = 2.8 mg/m3 were predictive of a work period decrement of > or = 10% in FEV1. Ammonia concentrations of > or = 7.5 ppm were predictive of a > or = 3% work period decrement in FEV1. These predictive concentrations were similar to a previous dose-response study, which suggested 2.5 mg/m3 of total dust and 7 ppm of NH3 were associated with significant work period decrements. Therefore, dust > or = 2.8 mg/m3 and ammonia > or = 7.5 ppm should be considered reasonable evidence for guidelines regarding hazardous exposure concentrations in this work environment.

  11. Dose-response relationships for female radium dial workers: A new look

    International Nuclear Information System (INIS)

    Rowland, R.E.

    1994-01-01

    The values of initial systemic intake and of skeletal dose for all of the U.S. radium cases have recently been revised. This revision was required following the demonstrations by Rundo and by Keane that humans who were exposed to radium as adults lost radium at a rate that depended on the quantity of radium originally deposited within their bodies. These new values have been used to define new dose-response relationships for both the bone sarcomas and the carcinomas arising in the paranasal sinuses and mastoid air cells induced by internally deposited radium. The population examined was employed in the U.S. dial painting industry prior to 1950 and consisted of 1530 female dial workers for whom radium body burden measurements were available. By the end of 1990, 46 cases of bone sarcomas and 19 cases of head carcinomas had been diagnosed in this cohort. The head carcinoma incidence can be adequately fitted by a simple linear function, as was found in previous analyses. The bone sarcoma cases were previously fitted by a dose-squared-exponential function. With the revised values of systemic intake, the sarcoma results could not be satisfactorily fitted with this expression. When the exponent on D was increased to larger values, excellent fits were obtained

  12. The dose-response relationship of balance training in physically active older adults.

    Science.gov (United States)

    Maughan, Kristen K; Lowry, Kristin A; Franke, Warren D; Smiley-Oyen, Ann L

    2012-10-01

    A 6-wk group balance-training program was conducted with physically active older adults (based on American College of Sports Medicine requirements) to investigate the effect of dose-related static and dynamic balance-specific training. All participants, age 60-87 yr, continued their regular exercise program while adding balance training in 1 of 3 doses: three 20-min sessions/wk (n = 20), one 20-min session/wk (n = 21), or no balance training (n = 19). Static balance (single-leg-stance, tandem), dynamic balance (alternate stepping, limits of stability), and balance confidence (ABC) were assessed pre- and posttraining. Significant interactions were observed for time in single-leg stance, excursion in limits of stability, and balance confidence, with the greatest increase observed in the group that completed 3 training sessions/wk. The results demonstrate a dose-response relationship indicating that those who are already physically active can improve balance performance with the addition of balance-specific training.

  13. Dose-response relationship of autonomic nervous system responses to individualized training impulse in marathon runners.

    Science.gov (United States)

    Manzi, Vincenzo; Castagna, Carlo; Padua, Elvira; Lombardo, Mauro; D'Ottavio, Stefano; Massaro, Michele; Volterrani, Maurizio; Iellamo, Ferdinando

    2009-06-01

    In athletes, exercise training induces autonomic nervous system (ANS) adaptations that could be used to monitor training status. However, the relationship between training and ANS in athletes has been investigated without regard for individual training loads. We tested the hypothesis that in long-distance athletes, changes in ANS parameters are dose-response related to individual volume/intensity training load and could predict athletic performance. A spectral analysis of heart rate (HR), systolic arterial pressure variability, and baroreflex sensitivity by the sequences technique was investigated in eight recreational athletes during a 6-mo training period culminating with a marathon. Individualized training load responses were monitored by a modified training impulse (TRIMP(i)) method, which was determined in each athlete using the individual HR and lactate profiling determined during a treadmill test. Monthly TRIMP(i) steadily increased during the training period. All the ANS parameters were significantly and very highly correlated to the dose of exercise with a second-order regression model (r(2) ranged from 0.90 to 0.99; P marathon. These results suggest that in recreational athletes, ANS adaptations to exercise training are dose related on an individual basis, showing a progressive shift toward a sympathetic predominance, and that LF oscillations in HRV at peak training load could predict athletic achievement in this athlete population.

  14. Using plant biomonitors and flux modelling to develop O3 dose-response relationships in Catalonia

    International Nuclear Information System (INIS)

    Filella, Iolanda; Pen-tilde uelas, Josep; Ribas, Angela

    2005-01-01

    We used tobacco Bel-W3 biomonitoring data and ozone flux modelling (WINDEP model) with the aim of developing the absorbed dose-response relationship, and comparing this approach with the most commonly used AOT40 (the sum of hourly ozone concentrations above a cut-off of 40 ppb during daylight hours, when global radiation exceeds 50 W m -2 ) in the estimation of exposure-damage curves. Leaf damage values were more related to OAD 15days,potential (potential ozone absorbed dose calculated over 15 consecutive days) than to AOT40 in all the studied stations. An OAD 15days,potential of 180 mg m -2 was found to be the threshold for damage to the most sensitive species in this region under well watered conditions. The results show the applicability of the flux approach for risk assessment at the local scale, the improvement of the ozone damage estimation when the potential absorbed dose is modelled and used instead of just the ozone exposure, and finally, the possibilities opened by the use of biomonitoring networks. - Modelling of biomonitors ozone absorbed dose improves damage estimation in comparison with exposure indices such as AOT40

  15. New flux based dose-response relationships for ozone for European forest tree species.

    Science.gov (United States)

    Büker, P; Feng, Z; Uddling, J; Briolat, A; Alonso, R; Braun, S; Elvira, S; Gerosa, G; Karlsson, P E; Le Thiec, D; Marzuoli, R; Mills, G; Oksanen, E; Wieser, G; Wilkinson, M; Emberson, L D

    2015-11-01

    To derive O3 dose-response relationships (DRR) for five European forest trees species and broadleaf deciduous and needleleaf tree plant functional types (PFTs), phytotoxic O3 doses (PODy) were related to biomass reductions. PODy was calculated using a stomatal flux model with a range of cut-off thresholds (y) indicative of varying detoxification capacities. Linear regression analysis showed that DRR for PFT and individual tree species differed in their robustness. A simplified parameterisation of the flux model was tested and showed that for most non-Mediterranean tree species, this simplified model led to similarly robust DRR as compared to a species- and climate region-specific parameterisation. Experimentally induced soil water stress was not found to substantially reduce PODy, mainly due to the short duration of soil water stress periods. This study validates the stomatal O3 flux concept and represents a step forward in predicting O3 damage to forests in a spatially and temporally varying climate. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

  16. Influence of image slice thickness on rectal dose-response relationships following radiotherapy of prostate cancer

    Science.gov (United States)

    Olsson, C.; Thor, M.; Liu, M.; Moissenko, V.; Petersen, S. E.; Høyer, M.; Apte, A.; Deasy, J. O.

    2014-07-01

    When pooling retrospective data from different cohorts, slice thicknesses of acquired computed tomography (CT) images used for treatment planning may vary between cohorts. It is, however, not known if varying slice thickness influences derived dose-response relationships. We investigated this for rectal bleeding using dose-volume histograms (DVHs) of the rectum and rectal wall for dose distributions superimposed on images with varying CT slice thicknesses. We used dose and endpoint data from two prostate cancer cohorts treated with three-dimensional conformal radiotherapy to either 74 Gy (N = 159) or 78 Gy (N = 159) at 2 Gy per fraction. The rectum was defined as the whole organ with content, and the morbidity cut-off was Grade ≥2 late rectal bleeding. Rectal walls were defined as 3 mm inner margins added to the rectum. DVHs for simulated slice thicknesses from 3 to 13 mm were compared to DVHs for the originally acquired slice thicknesses at 3 and 5 mm. Volumes, mean, and maximum doses were assessed from the DVHs, and generalized equivalent uniform dose (gEUD) values were calculated. For each organ and each of the simulated slice thicknesses, we performed predictive modeling of late rectal bleeding using the Lyman-Kutcher-Burman (LKB) model. For the most coarse slice thickness, rectal volumes increased (≤18%), whereas maximum and mean doses decreased (≤0.8 and ≤4.2 Gy, respectively). For all a values, the gEUD for the simulated DVHs were ≤1.9 Gy different than the gEUD for the original DVHs. The best-fitting LKB model parameter values with 95% CIs were consistent between all DVHs. In conclusion, we found that the investigated slice thickness variations had minimal impact on rectal dose-response estimations. From the perspective of predictive modeling, our results suggest that variations within 10 mm in slice thickness between cohorts are unlikely to be a limiting factor when pooling multi-institutional rectal dose data that include slice thickness

  17. The crooked shall be made straight: dose response relationships for carcinogenesis

    International Nuclear Information System (INIS)

    Hall, E.J.

    2003-01-01

    Estimates of radiation-induced malignancies come principally from the A-bomb survivors and from medically exposed individuals, including second cancers in radiotherapy patients. The A-bomb survivors show an excess incidence of carcinomas which is linear with dose from about 10 cGy to 2.5 Gy. Above and below this dose range, there is considerable uncertainty concerning the shape of the dose response relationship. These two dose ranges will be discussed separately. Low dose extrapolations ICRP and NCRP suggest that cancer risks at doses lower than those at which direct epidemiological observations are possible should be obtained by a linear extrapolation from higher doses. This is labeled a 'prudent and conservative' assumption but is a subject of considerable controversy. Two factors, the existence of radiosensitive subgroups in the human population (such as AT heterozygotes), and the demonstration of a Bystander effect both exaggerate the consequences of small doses of radiation and imply that a linear extrapolation from high doses would underestimate low dose risks. High dose extrapolations In the context of radiotherapy, some normal tissues receive 70 Gy, while a larger volume receives a lower dose, but still far higher than the range for which data are available from the A-bomb survivors. The question is, what is the dose response for carcinogenesis in the range 10 to 70 Gy? At one extreme, it might be expected that the risk of inducing cancer would fall off rapidly at higher does due to cell killing. The other extreme possibility is that the risk of solid tumors levels off by about 10 Gy, but does not decline thereafter. For a few cancers, data are available from 2 Gy in A-bomb survivors to 70 Gy in radiotherapy patients, and it appears that the relative risk does not vary with dose. This implies that the volume of tissue irradiated is more important than the maximum dose. This result has far reaching implications for new technologies such as IMRT, which

  18. Dose-response relationship of octylphenol and radiation evaluated by tradescantia-micronucleus assay

    International Nuclear Information System (INIS)

    Kim, J. K.; Cheon, K. J.; Lee, B. H.; Shin, H. S.; Lee, J. H.

    2002-01-01

    Many kinds of synthetic chemicals have been being used for various purposes. Some of them are called 'Endocrine Disruptor's because they can disturb the endocrine system of organisms. Presently no technique is established for the quantitative assessment of biological risk of the environmental hormones. The pollen mother cells (PMC) of Tradescantia are very sensitive to chemical toxicants or ionizing radiation, and thus can be used as a biological end-point assessing their effect. Micronucleus frequencies in PMC showed a good dose- and concentration-response relationship for radiation, bisphenol A and octylphenol. A parallel series of experiment using five increasing doses of gamma-ray at 10, 20, 30, 40 and 50 cGy was conducted. The MCN frequencies of 12.0, 25.2, 41.7, 76 and 83 MCN/100 tetrads were observed from each of the increasing gamma-ray dosage groups, respectively. Lenear regression analysis of the gamma-ray data MCN frequencies yielded a correlation coefficient of 0.95. the MCN frequencies in pollen mother cells treated with bisphenol a and octylphenol showed dose-response relationship in a concentration of 0, 1, 2, 4 μM and 0, 4, 10, 20 μM. the MCN frequency for the bisphenol a and octylphenol group yields 2.33, 8.06, 12.7 and 19.6 MCN/100 tetrads for the bisphenol a and 2.33, 2.33, 11.47, 17.6 MCN/100 tetrads for the octylphenol. The MCN frequency of the control was 2.33 MCN/100 tetrads. It is known from the result that Trad-MCN assay can be an excellent tool for detection of biological risk due to environmental toxicants or synthetic chemicals

  19. Exercise volume and intensity: a dose-response relationship with health benefits.

    Science.gov (United States)

    Foulds, Heather J A; Bredin, Shannon S D; Charlesworth, Sarah A; Ivey, Adam C; Warburton, Darren E R

    2014-08-01

    The health benefits of exercise are well established. However, the relationship between exercise volume and intensity and health benefits remains unclear, particularly the benefits of low-volume and intensity exercise. The primary purpose of this investigation was, therefore, to examine the dose-response relationship between exercise volume and intensity with derived health benefits including volumes and intensity of activity well below international recommendations. Generally healthy, active participants (n = 72; age = 44 ± 13 years) were assigned randomly to control (n = 10) or one of five 13-week exercise programs: (1) 10-min brisk walking 1×/week (n = 10), (2) 10-min brisk walking 3×/week (n = 10), (3) 30-min brisk walking 3×/week (n = 18), (4) 60-min brisk walking 3×/week (n = 10), and (5) 30-min running 3×/week (n = 14), in addition to their regular physical activity. Health measures evaluated pre- and post-training including blood pressure, body composition, fasting lipids and glucose, and maximal aerobic power (VO2max). Health improvements were observed among programs at least 30 min in duration, including body composition and VO2max: 30-min walking 28.8-34.5 mL kg(-1) min(-1), 60-min walking 25.1-28.9 mL kg(-1) min(-1), and 30-min running 32.4-36.4 mL kg(-1) min(-1). The greater intensity running program also demonstrated improvements in triglycerides. In healthy active individuals, a physical activity program of at least 30 min in duration for three sessions/per week is associated with consistent improvements in health status.

  20. Dose-Response Relationships of Resistance Training in Healthy Old Adults : A Systematic Review and Meta-Analysis

    NARCIS (Netherlands)

    Borde, Ron; Hortobagyi, Tibor; Granacher, Urs

    2015-01-01

    Background Resistance training (RT) is an intervention frequently used to improve muscle strength and morphology in old age. However, evidence-based, dose-response relationships regarding specific RT variables (e.g., training period, frequency, intensity, volume) are unclear in healthy old adults.

  1. Continuous Dose-Response Response Relationship of the LDL-Cholesterol-Lowering Effect of Phytosterol Intake 1,2

    NARCIS (Netherlands)

    Demonty, I.; Ras, R.T.; Knaap, van der H.C.M.; Duchateau, G.S.M.J.E.; Meijer, L.; Zock, P.L.; Geleijnse, J.M.; Trautwein, E.A.

    2009-01-01

    Phytosterols (plant sterols and stanols) are well known for their LDL-cholesterol (LDL-C)¿lowering effect. A meta-analysis of randomized controlled trials in adults was performed to establish a continuous dose-response relationship that would allow predicting the LDL-C¿lowering efficacy of different

  2. Dose-response relationships for enzyme replacement therapy with imiglucerase/alglucerase in patients with Gaucher disease type 1

    NARCIS (Netherlands)

    Grabowski, Gregory A.; Kacena, Katherine; Cole, J. Alexander; Hollak, Carla E. M.; Zhang, Lin; Yee, John; Mistry, Pramod K.; Zimran, Ari; Charrow, Joel; vom Dahl, Stephan

    2009-01-01

    Purpose: To determine whether enzyme therapy with imiglucerase/ alglucerase demonstrates dose-response relationships with doses and disease parameters used in routine clinical practice for Gaucher disease type 1 patients. Methods: Analyses included all patients with Gaucher disease type 1 on enzyme

  3. European Academy of Allergy and Clinical Immunology task force report on 'dose-response relationship in allergen-specific immunotherapy'

    DEFF Research Database (Denmark)

    Calderón, M A; Larenas, D; Kleine-Tebbe, J

    2011-01-01

    For a century, allergen-specific immunotherapy (SIT) has proven to be an effective treatment for allergic rhinitis, asthma, and insect sting allergy. However, as allergen doses are frequently adapted to the individual patient, there are few data on dose-response relationship in SIT. Allergen prod...

  4. Dose-Response Relationships of Balance Training in Healthy Young Adults : A Systematic Review and Meta-Analysis

    NARCIS (Netherlands)

    Lesinski, Melanie; Hortobagyi, Tibor; Muehlbauer, Thomas; Gollhofer, Albert; Granacher, Urs

    Background Balance training (BT) has been used for the promotion of balance and sports-related skills as well as for prevention and rehabilitation of lower extremity sport injuries. However, evidence-based dose-response relationships in BT parameters have not yet been established. Objective The

  5. Youth suicide attempts and the dose-response relationship to parental risk factors: a population-based study

    DEFF Research Database (Denmark)

    Christiansen, E; Goldney, R D; Beautrai, A L

    2011-01-01

    BACKGROUND: There is a lack of specific knowledge about the dose-response effect of multiple parental risk factors for suicide attempts among children and adolescents. The aim of this study was to determine the dose-response effect of multiple parental risk factors on an offspring's risk for suic......BACKGROUND: There is a lack of specific knowledge about the dose-response effect of multiple parental risk factors for suicide attempts among children and adolescents. The aim of this study was to determine the dose-response effect of multiple parental risk factors on an offspring's risk...... for suicide attempt.MethodWe designed a population-based two-generation nested case-control study and used Danish register data. A population of 403 431 individuals born between 1983 and 1989 was sampled. Among these, 3465 (0.8%) were registered as having had a suicide attempt. Twenty controls were matched...... to each case and a link to the offspring's biological parents was established. RESULTS: There was a dose-response relationship between the number of exposures and the risk of suicide attempts, with the increased risk seeming to be a multiplicative effect. Parental suicide, suicide attempt, psychiatric...

  6. Critical reevaluation of the dose-response relationships for carcinogenic effects of low-level ionizing radiation

    International Nuclear Information System (INIS)

    Upton, A.C.

    2003-01-01

    In recent decades, it has been customary, for radiation protection purposes, to assume that the overall risk of radiation-induced cancer increases as a linear-nonthreshold function of the dose. The existing data do not exclude the existence of a threshold, however, and the dose-response relationship is known to vary, depending on the type of cancer in queation, the dose, dose rate, and LET of the radiation, the age, sex, and physiological state of the exposed individuals, and other variables, including the potential influence of adaptive responses and bystander effects at low doses. In light of advncing knowledge, therefore, the dose-response relationship for carcinogenic effects of low-level radiation has been reevaluated periodically by the National Council on Radiation Protection and Measurements, the International Commission of Radiological Protection, the United Nations Scientific Committee on the Effects of Atomic Radiation, the U.S. National Academy of Sciences, and other organizations. The most recent such reviews have generally found the weight of evidence to suggest that lesions which are precursors to cancer (i.e., mutations and chromosome aberrations), and certain types of cancer as well, may increase in frequency linearly with the dose in the low-dose domain. On this basis, it is concluded that no alternative dose-response model for the carcinogenic effects of low-level radiation is more plausible than the linear-nonthreshold model, although other dose-response relationships cannot be excluded. (authors)

  7. Teratogenic radiation effects: Phenomena, dose-response relationships and risk levels

    International Nuclear Information System (INIS)

    Konermann, G.

    1991-01-01

    The report in hand informs about a study performed within the framework of the research project 'Animal experiments with albino mice for establishing a model for the detection and assessment of radiation-induced, developmental risks in man due to low-dose irradiation'. The subjects investigated in this study are: (1) Dose-response relationships for postnatal developmental disturbances of the brain as a result of prenatal X-ray treatment. (2) Biokinetics, distribution patterns and effects of inorganically and organically bonded radioiodine (I-125) during the phase of development of the brain. For investigation of the first-mentioned subject, computerized microphotograph analysis was applied for detecting and assessing disturbances of the alignment of axons, as well as deviations from normal cross-sectional data of the Cortex layer, and cerebral commissures as final locations of neurogenetic damage. With all parameters studied, the slope of the relevant curves was found to decrease as a function of age of the fetus at the time of exposure. In addition, time factor effects were investigated. For the parameter cross-sectional area of the Cortex, a clear decrease of effect was found, but for all other parameters, reactions were ambiguous. The study into the second subject was done with cell cultures, showing that the I-125 bonded to the cell nucleus has a much stronger radiotoxic effect than I-125 bonded to the cytoplasma. This difference in effect was studied in mice after incorporation of equal doses administered by way of (I-125)-sodium iodide or (I-125)-iododesoxyuridine. Long-term effects on Cortex cross-sectional areas, cerebral commissures or the texture of axons were quantified by microphotograph analysis. Acute cell death and initial disturbances of the neuronal cell growth were evident after incorporation of (I-125)-IdUR, but not detectable after administration of (I-125)-NaI. (orig./MG) [de

  8. Leisure time physical activity and mortality: a detailed pooled analysis of the dose-response relationship.

    Science.gov (United States)

    Arem, Hannah; Moore, Steven C; Patel, Alpa; Hartge, Patricia; Berrington de Gonzalez, Amy; Visvanathan, Kala; Campbell, Peter T; Freedman, Michal; Weiderpass, Elisabete; Adami, Hans Olov; Linet, Martha S; Lee, I-Min; Matthews, Charles E

    2015-06-01

    , 0.69 [95% CI, 0.59-0.78]). A similar dose-response relationship was observed for mortality due to cardiovascular disease and to cancer. Meeting the 2008 Physical Activity Guidelines for Americans minimum by either moderate- or vigorous-intensity activities was associated with nearly the maximum longevity benefit. We observed a benefit threshold at approximately 3 to 5 times the recommended leisure time physical activity minimum and no excess risk at 10 or more times the minimum. In regard to mortality, health care professionals should encourage inactive adults to perform leisure time physical activity and do not need to discourage adults who already participate in high-activity levels.

  9. Is There a Dose-Response Relationship for Heart Disease With Low-Dose Radiation Therapy?

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Eugene [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Corbett, James R. [Division of Nuclear Medicine, Department of Radiology, University of Michigan, Ann Arbor, Michigan (United States); Moran, Jean M. [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Griffith, Kent A. [Department of Biostatistics, University of Michigan, Ann Arbor, Michigan (United States); Marsh, Robin B.; Feng, Mary; Jagsi, Reshma; Kessler, Marc L. [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Ficaro, Edward C. [Division of Nuclear Medicine, Department of Radiology, University of Michigan, Ann Arbor, Michigan (United States); Pierce, Lori J., E-mail: ljpierce@umich.edu [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States)

    2013-03-15

    Purpose: To quantify cardiac radiation therapy (RT) exposure using sensitive measures of cardiac dysfunction; and to correlate dysfunction with heart doses, in the setting of adjuvant RT for left-sided breast cancer. Methods and Materials: On a randomized trial, 32 women with node-positive left-sided breast cancer underwent pre-RT stress single photon emission computed tomography (SPECT-CT) myocardial perfusion scans. Patients received RT to the breast/chest wall and regional lymph nodes to doses of 50 to 52.2 Gy. Repeat SPECT-CT scans were performed 1 year after RT. Perfusion defects (PD), summed stress defects scores (SSS), and ejection fractions (EF) were evaluated. Doses to the heart and coronary arteries were quantified. Results: The mean difference in pre- and post-RT PD was −0.38% ± 3.20% (P=.68), with no clinically significant defects. To assess for subclinical effects, PD were also examined using a 1.5-SD below the normal mean threshold, with a mean difference of 2.53% ± 12.57% (P=.38). The mean differences in SSS and EF before and after RT were 0.78% ± 2.50% (P=.08) and 1.75% ± 7.29% (P=.39), respectively. The average heart Dmean and D95 were 2.82 Gy (range, 1.11-6.06 Gy) and 0.90 Gy (range, 0.13-2.17 Gy), respectively. The average Dmean and D95 to the left anterior descending artery were 7.22 Gy (range, 2.58-18.05 Gy) and 3.22 Gy (range, 1.23-6.86 Gy), respectively. No correlations were found between cardiac doses and changes in PD, SSS, and EF. Conclusions: Using sensitive measures of cardiac function, no clinically significant defects were found after RT, with the average heart Dmean <5 Gy. Although a dose response may exist for measures of cardiac dysfunction at higher doses, no correlation was found in the present study for low doses delivered to cardiac structures and perfusion, SSS, or EF.

  10. Human cytogenetic dosimetry: a dose-response relationship for alpha particle radiation from 241Am

    International Nuclear Information System (INIS)

    DuFrain, R.J.; Littlefield, L.G.; Joiner, E.E.; Frome, E.L.

    1979-01-01

    Cytogenetic dosimetry estimates to guide treatment of persons internally contaminated with transuranic elements have not previously been possible because appropriate in vitro dose-response curves specifically for alpha particle irradiation of human lymphocytes do not exist. Using well-controlled cytogenetic methods for human lymphocyte culture, an experimentally derived dose-response curve for 241 Am alpha particle (5.49 and 5.44 MeV) radiation of G 0 lymphocytes was generated. Cells were exposed to 43.8, 87.7, 175.3 or 350.6 nCi/ml 241 Am for 1.7 hr giving doses of 0.85, 1.71, 3.42 or 6.84 rad. Based on dicentric chromosome yield, the linear dose-response equation is Y = 4.90(+-0.42) x 10 -2 X, with Y given as dicentrics per cell and X as dose in rads. The study also shows that the two-break asymmetrical exchanges in cells damaged by alpha particle radiation are overdispersed when compared to a Poisson distribution. An example is presented to show how the derived dose-response equation can be used to estimate the radiation dose for a person internally contaminated with an actinide. An experimentally derived RBE value of 118 at 0.85 rad is calculated for the efficiency of 241 Am alpha particle induction of dicentric chromosomes in human G 0 lymphocytes as compared with the efficiency of 60 Co gamma radiation. The maximum theoretical value for the RBE for cytogenetic damage from alpha irradiation was determined to be 278 at 0.1 rad or less which is in marked contrast to previously reported RBE values of approx. 20. (author)

  11. Gustatory tissue injury in man: radiation dose response relationships and mechanisms of taste loss

    International Nuclear Information System (INIS)

    Mossman, K.L.

    1986-01-01

    In this report dose response data for gustatory tissue damage in patients given total radiation doses ranging from 3000 to 6000 cGy are presented. In order to evaluate direct radiation injury to gustatory tissues as a mechanism of taste loss, measurements of damage to specific taste structures in bovine and murine systems following radiation exposure in the clinical range are correlated to taste impairment observed in radiotherapy patients. (author)

  12. Linear and Non-Linear Dose-Response Functions Reveal a Hormetic Relationship Between Stress and Learning

    OpenAIRE

    Zoladz, Phillip R.; Diamond, David M.

    2008-01-01

    Over a century of behavioral research has shown that stress can enhance or impair learning and memory. In the present review, we have explored the complex effects of stress on cognition and propose that they are characterized by linear and non-linear dose-response functions, which together reveal a hormetic relationship between stress and learning. We suggest that stress initially enhances hippocampal function, resulting from amygdala-induced excitation of hippocampal synaptic plasticity, as ...

  13. The dose-response relationship between cumulative lifting load and lumbar disk degeneration based on magnetic resonance imaging findings.

    Science.gov (United States)

    Hung, Yu-Ju; Shih, Tiffany T-F; Chen, Bang-Bin; Hwang, Yaw-Huei; Ma, Li-Ping; Huang, Wen-Chuan; Liou, Saou-Hsing; Ho, Ing-Kang; Guo, Yue L

    2014-11-01

    Lumbar disk degeneration (LDD) has been related to heavy physical loading. However, the quantification of the exposure has been controversial, and the dose-response relationship with the LDD has not been established. The purpose of this study was to investigate the dose-response relationship between lifetime cumulative lifting load and LDD. This was a cross-sectional study. Every participant received assessments with a questionnaire, magnetic resonance imaging (MRI) of the lumbar spine, and estimation of lumbar disk compression load. The MRI assessments included assessment of disk dehydration, annulus tear, disk height narrowing, bulging, protrusion, extrusion, sequestration, degenerative and spondylolytic spondylolisthesis, foramina narrowing, and nerve root compression on each lumbar disk level. The compression load was predicted using a biomechanical software system. A total of 553 participants were recruited in this study and categorized into tertiles by cumulative lifting load (ie, lifting load. The best dose-response relationships were found at the L5-S1 disk level, in which high cumulative lifting load was associated with elevated odds ratios of 2.5 (95% confidence interval [95% CI]=1.5, 4.1) for dehydration and 4.1 (95% CI=1.9, 10.1) for disk height narrowing compared with low lifting load. Participants exposed to intermediate lifting load had an increased odds ratio of 2.1 (95% CI=1.3, 3.3) for bulging compared with low lifting load. The tests for trend were significant. There is no "gold standard" assessment tool for measuring the lumbar compression load. The results suggest a dose-response relationship between cumulative lifting load and LDD. © 2014 American Physical Therapy Association.

  14. Linear and non-linear dose-response functions reveal a hormetic relationship between stress and learning.

    Science.gov (United States)

    Zoladz, Phillip R; Diamond, David M

    2008-10-16

    Over a century of behavioral research has shown that stress can enhance or impair learning and memory. In the present review, we have explored the complex effects of stress on cognition and propose that they are characterized by linear and non-linear dose-response functions, which together reveal a hormetic relationship between stress and learning. We suggest that stress initially enhances hippocampal function, resulting from amygdala-induced excitation of hippocampal synaptic plasticity, as well as the excitatory effects of several neuromodulators, including corticosteroids, norepinephrine, corticotropin-releasing hormone, acetylcholine and dopamine. We propose that this rapid activation of the amygdala-hippocampus brain memory system results in a linear dose-response relation between emotional strength and memory formation. More prolonged stress, however, leads to an inhibition of hippocampal function, which can be attributed to compensatory cellular responses that protect hippocampal neurons from excitotoxicity. This inhibition of hippocampal functioning in response to prolonged stress is potentially relevant to the well-described curvilinear dose-response relationship between arousal and memory. Our emphasis on the temporal features of stress-brain interactions addresses how stress can activate, as well as impair, hippocampal functioning to produce a hormetic relationship between stress and learning.

  15. Critical reevaluation of the dose-response relationships for carcinogenic effects of low-level ionizing radiation

    International Nuclear Information System (INIS)

    Upton, Arthur C.

    2002-01-01

    In recent decades, it has been customary, for radiation protection purposes, to assume that the overall risk of radiation- included cancer increases as a linear-nonthreshold function of the dose. The existing data do not exclude the existence of a threshold, however, and the dose-response relationship is known to vary depending on the type of cancer in question, the dose, dose rate and LET of the radiation, the age, sex and physiological state of the exposed individuals, and other variables, including the potential influence of adaptive responses and bystander effects at low doses. In light of advancing knowledge, therefore, the dose-response relationship for carcinogenic effects of low-level radiation has been reevaluated periodically by the National Council on Radiation Protection and Measurements, the International Commission of Radiological Protection, the United Nations Scientific Committee on the Effects of Atomic Radiation, the U.S. National Academy of Sciences Committee on the Effects of Atomic Radiation, the U.S. National Academy of Sciences, and other organizations. The most recent such reviews have generally found the weight of evidence to suggest that lesions which are precursors to cancer (i.e., mutations and chromosome aberrations), and certain types of cancer as well, may increase in frequency linearly aberrations), and certain types of cancer as well, may increase in frequency linearly with the dose in the low-dose domain. On this basis, it is concluded that no alternative dose-response model for the carcinogenic effects of low-level radiation is ore plausible than the linear-nonthreshold model, although other dose-response relationships cannot be excluded. (author)

  16. Comparison of the dose-response relationships for chromosome aberration frequencies between the T65D and DS86 dosimetries

    International Nuclear Information System (INIS)

    Preston, D.L.; McConney, M.E.; Awa, A.A.; Ohtaki, Kazuo; Itoh, Masahiro; Honda, Takeo.

    1989-05-01

    Cytogenetic data, derived from cultured lymphocytes of atomic bomb survivors and controls in the ABCC-RERF Adult Health Study cohort, have been analyzed to determine differences in the dose-response relationships for chromosome aberrations between the T65D and DS86 dose estimates and to assess differences between Hiroshima and Nagasaki. For a linear dose-response model, the average percentage of cells with at least one chromosome aberration increases less rapidly with dose in Nagasaki than in Hiroshima. The magnitude of the intercity difference in the percentage of cells with aberrations per gray is less for DS86 than for T65D, though the difference is statistically significant for both kerma and bone marrow dose with either dosimetry. The percentage of cells with aberrations per gray for DS86 kerma estimates is about 60 % greater than the corresponding T65D slope. Analyses to test nonlinearity in the dose-response function indicate significant departures (p<.001) from linearity, using both dosimetries for both kerma and marrow dose. Therefore, comparative results are presented for a range of RBE relationships under various linear (L) and linearquadratic linear (LQ-L) models. As an illustrative result, if one assumes an LQ-L model similar to models reported in the cytogenetic literature, with a limiting RBE of 20 at zero dose, the DS86 slope (the percentage of cells with aberrations per sievert) is 120 % greater than the corresponding T65D value. (J.P.N.)

  17. Dose-response relationships between exercise intensity, cravings, and inhibitory control in methamphetamine dependence: An ERPs study.

    Science.gov (United States)

    Wang, Dongshi; Zhou, Chenglin; Zhao, Min; Wu, Xueping; Chang, Yu-Kai

    2016-04-01

    The present study integrated behavioral and neuroelectric approaches for determining the dose-response relationships between exercise intensity and methamphetamine (MA) craving and between exercise intensity and inhibitory control in individuals with MA dependence. Ninety-two individuals with MA dependence were randomly assigned to an exercise group (light, moderate, or vigorous intensity) or to a reading control group. The participants then completed a craving self-report at four time points: before exercise, during exercise, immediately after exercise, and 50 min after exercise. Event-related potentials were also recorded while the participants completed a standard Go/NoGo task and an MA-related Go/NoGo task approximately 20 min after exercise cessation. The reduction in self-reported MA craving scores of the moderate and vigorous intensity groups was greater than that of the light intensity and control groups during acute exercise as well as immediately and 50 min following exercise termination. Additionally, an inverted-U-shaped relationship between exercise intensity and inhibitory control was generally observed for the behavioral and neuroelectric indices, with the moderate intensity group exhibiting shorter Go reaction times, increased NoGo accuracy, and larger NoGo-N2 amplitudes. Acute exercise may provide benefits for MA-associated craving and inhibitory control in MA-dependent individuals, as revealed by behavioral and neuroelectric measures. Moderate-intensity exercise may be associated with more positive effects, providing preliminary evidence for the establishment of an exercise prescription regarding intensity for MA dependence. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  18. [Occlusion treatment for amblyopia. Age dependence and dose-response relationship].

    Science.gov (United States)

    Fronius, M

    2016-04-01

    Based on clinical experience and studies on animal models the age of 6-7 years was regarded as the limit for treatment of amblyopia, although functional improvement was also occasionally reported in older patients. New technical developments as well as insights from clinical studies and the neurosciences have attracted considerable attention to this topic. Various aspects of the age dependence of amblyopia treatment are discussed in this article, e. g. prescription, electronic monitoring of occlusion dosage, calculation of indicators for age-dependent plasticity of the visual system, and novel, alternative treatment approaches. Besides a discussion of the recent literature, results of studies by our "Child Vision Research Unit" in Frankfurt are presented: results of a questionnaire about prescription habits concerning age limits of patching, electronic recording of occlusion in patients beyond the conventional treatment age, calculation of dose-response function and efficiency of patching and their age dependence. The results of the questionnaire illustrate the uncertainty about age limits of prescription with significant deviations from the guideline of the German Ophthalmological Society (DOG). Electronic recording of occlusion allowed the quantification of declining dose-response function and treatment efficiency between 5 and 16 years of age. Reports about successful treatment with conventional and novel methods in adults are at variance with the notion of a rigid adult visual system lacking plasticity. Electronic recording of patching allowed new insights into the age-dependent susceptibility of the visual system and contributes to a more evidence-based treatment of amblyopia. Alternative approaches for adults challenge established notions about age limits of amblyopia therapy. Further studies comparing different treatment options are urgently needed.

  19. Comparison of the dose-response relationship of radiation-induced apoptosis in the hippocampal dentate gyrus and intestinal crypt of adult mice

    International Nuclear Information System (INIS)

    Kim, J. S.; Yang, M.; Kim, J.; Lee, D.; Kim, J. C.; Shin, T.; Kim, S. H.; Moon, C.

    2012-01-01

    The present study compared the dose-response curves for the frequency of apoptosis in mouse hippocampal dentate gyrus (DG) and intestinal crypt using whole-body gamma irradiation. The incidence of gamma-ray-induced apoptosis was measured using the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end-labelling (TUNEL) method. TUNEL-positive apoptotic nuclei in the DG and intestinal crypt were increased in a dose-dependent pattern (0-2 Gy). The dose-response curves were linear-quadratic, with a significant relationship between the appearance of apoptosis and irradiation dose. The slopes of the dose-response curves in the DG were much steeper (∼5-6-fold) than those in the intestinal crypt within the range of 0-1 Gy exposure. Hippocampal DG might be a more effective and sensitive evaluation structure than the intestinal crypt to estimate the degree of radiation exposure in damaged organs of adult mice exposed to low irradiation dose. copy; The Author 2011. Published by Oxford Univ. Press. All rights reserved. (authors)

  20. Augmentation index (AI) in a dose-response relationship with smoking habits in males: The Tanushimaru study.

    Science.gov (United States)

    Tsuru, Tomoko; Adachi, Hisashi; Enomoto, Mika; Fukami, Ako; Kumagai, Eita; Nakamura, Sachiko; Nohara, Yume; Kono, Shoko; Nakao, Erika; Sakaue, Akiko; Morikawa, Nagisa; Fukumoto, Yoshihiro

    2016-12-01

    We investigated the relationship between augmentation index (AI) and smoking habits in community-dwelling Japanese.This cross-sectional study enrolled 1926 subjects (769 males and 1157 females) aged 40 to 95 years who underwent a health check-up in a Japanese cohort of the Seven Countries Study, in Tanushimaru, a typical farming town in Kyushu Island in 2009. The subjects' medical history, alcohol intake, smoking habit, and current medications for hypertension, dyslipidemia, and diabetes were ascertained by questionnaire. Radial arterial pressure wave analysis was used to obtain AI. We analyzed the data stratified by gender.Age-adjusted means of AI in males showed a clear dose-response relationship in 4 categories of smoking habits (P = 0.010). There was no significant relationship between AI and smoking habits in females (P = 0.127). The significant dose-response relationship (P = 0.036) in males between AI and 4 categories of smoking habits still remained even after adjustment for age, body mass index, systolic blood pressure, estimated glomerular filtration rate, glucose, hypertensive medication, and alcohol intake.The present study demonstrated that AI values were significantly associated with smoking habits in a dose-dependent manner in Japanese males.

  1. The Time-Dose-Response Relationship for Elicitation of Contact Dermatitis in Isoeugenol Allergic Individuals

    DEFF Research Database (Denmark)

    Andersen, K. E.; Johansen, J. D.; Bruze, M.

    2001-01-01

    The elicitation response in allergic contact dermatitis is dose dependent, but the time-concentration relationship for elicitation has not previously been described. In this study 27 isoeugenol-sensitive patients participated in serial dilution patch tests with isoeugenol and a double-blinded Rep......The elicitation response in allergic contact dermatitis is dose dependent, but the time-concentration relationship for elicitation has not previously been described. In this study 27 isoeugenol-sensitive patients participated in serial dilution patch tests with isoeugenol and a double......-blinded Repeated Open Application Test (ROAT) using two concentrations of isoeugenol, 0.2 and 0.05%. Seven controls without isoeugenol allergy were also included. The participants applied 3.72 +/- 1.57 (mean +/- SD) mg/cm(2) of coded isoeugenol solutions twice a day to a 3 x 3 cm(2) area on the volar aspect...... of the right and left arm, respectively. For each test site the applications continued until a reaction appeared or for a maximum of 28 days. The minimal criteria for a positive reaction regarded as allergic contact dermatitis was persistent erythema at the ROAT test site. All controls were negative and 16...

  2. Chronic health effects in people exposed to arsenic via the drinking water: dose-response relationships in review

    International Nuclear Information System (INIS)

    Yoshida, Takahiko; Yamauchi, Hiroshi; Sun Guifan

    2004-01-01

    Chronic arsenic (As) poisoning has become a worldwide public health issue. Most human As exposure occurs from consumption of drinking water containing high amounts of inorganic As (iAs). In this paper, epidemiological studies conducted on the dose-response relationships between iAs exposure via the drinking water and related adverse health effects are reviewed. Before the review, the methods for evaluation of the individual As exposure are summarized and classified into two types, that is, the methods depending on As concentration of the drinking water and the methods depending on biological monitoring for As exposure; certain methods may be applied as optimum As exposure indexes to study dose-response relationship based on various As exposure situation. Chronic effects of iAs exposure via drinking water include skin lesions, neurological effects, hypertension, peripheral vascular disease, cardiovascular disease, respiratory disease, diabetes mellitus, and malignancies including skin cancer. The skin is quite sensitive to arsenic, and skin lesions are some of the most common and earliest nonmalignant effects related to chronic As exposure. The increase of prevalence in the skin lesions has been observed even at the exposure levels in the range of 0.005-0.01 mg/l As in drinking waters. Skin, lung, bladder, kidney, liver, and uterus are considered as sites As-induced malignancies, and the skin is though to be perhaps the most sensitive site. Prospective studies in large area of endemic As poisoning, like Bangladesh or China, where the rate of malignancies is expected to increase within the next several decades, will help to clarify the dose-response relationship between As exposure levels and adverse health effects with enhanced accuracy

  3. Internal and external generalizability of temporal dose-response relationships for xerostomia following IMRT for head and neck cancer.

    Science.gov (United States)

    Thor, Maria; Owosho, Adepitan A; Clark, Haley D; Oh, Jung Hun; Riaz, Nadeem; Hovan, Allan; Tsai, Jillian; Thomas, Steven D; Yom, Sae Hee K; Wu, Jonn S; Huryn, Joseph M; Moiseenko, Vitali; Lee, Nancy Y; Estilo, Cherry L; Deasy, Joseph O

    2017-02-01

    To study internal and external generalizability of temporal dose-response relationships for xerostomia after intensity-modulated radiotherapy (IMRT) for head and neck cancer, and to investigate potential amendments of the QUANTEC guidelines. Objective xerostomia was assessed in 121 patients (n Cohort1 =55; n Cohort2 =66) treated to 70Gy@2Gy in 2006-2015. Univariate and multivariate analyses (UVA, MVA with 1000 bootstrap populations) were conducted in Cohort1, and generalizability of the best-performing MVA model was investigated in Cohort2 (performance: AUC, p-values, and Hosmer-Lemeshow p-values (p HL )). Ultimately and for clinical guidance, minimum mean dose thresholds to the contralateral and the ipsilateral parotid glands (Dmean contra , Dmean ipsi ) were estimated from the generated dose-response curves. The observed xerostomia rate was 38%/47% (3months) and 19%/23% (11-12months) in Cohort1/Cohort2. Risk of xerostomia at 3months increased for higher Dmean contra and Dmean ipsi (Cohort1: 0.17·Dmean contra +0.11·Dmean ipsi -8.13; AUC=0.90±0.05; p=0.0002±0.002; p HL =0.22±0.23; Cohort2: AUC=0.81; pxerostomia following IMRT. Our results also suggest decreasing Dmean contra to below 20Gy, while keeping Dmean ipsi to around 25Gy. Long-term xerostomia was less frequent, and no dose-response relationship was established for this follow-up time. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  4. Dose-response relationship of γ-H2AX foci induction in human lymphocytes after X-rays exposure

    International Nuclear Information System (INIS)

    Mandina, Tania; Roch-Lefevre, Sandrine H.; Voisin, Pascale; Gonzalez, Jorge E.; Lamadrid, Ana I.; Romero, Ivonne; Garcia, Omar; Voisin, Philippe; Roy, Laurence

    2011-01-01

    Biological dosimeters are recommended for dose estimation in case of human overexposure to ionising radiation. Rapid measurement of γ-H2AX foci as a marker of DNA double-strand breaks (DSB) induction has been recently tested with this purpose. Here we reported a dose-response relationship after X-ray irradiation at different times post-exposure. Blood samples were obtained from several healthy donors and exposed to doses between 0 and 2 Gy. After irradiation, blood samples were incubated at 37 deg. C during 0.5 h, 5 h, and 8 h. Scoring of cells and γ-H2AX foci was performed by software. The dose-response curves for different incubation times were as follows: Y (0.5h) = 11.66D + 0.15 (R 2 = 0.99), Y (5h) = 2.44D + 0.15 (R 2 = 0.99), Y (8h) = 1.57D + 0.22 (R 2 = 0.99). At 0.5 h post-exposure, the dose-response relationship for X-irradiated lymphocytes was similar to the one obtained after gamma-irradiation using the same protocol. On the other hand, the results were not similar after 8 h due to different kinetics after gamma- and X-irradiation. Our results confirm the possibilities of using γ-H2AX foci method for dose estimation in a period from 0.5 h up to 8 h post X-irradiation and support the hypothesis of differences in γ-H2AX foci kinetics after gamma- and X-irradiation in vitro.

  5. Dose-response relationship of {gamma}-H2AX foci induction in human lymphocytes after X-rays exposure

    Energy Technology Data Exchange (ETDEWEB)

    Mandina, Tania [Centro de Proteccion e Higiene de las Radiaciones, Calle 20 No. 4113 e/41y 47 Miramar, AP 6195 C. Habana (Cuba); Roch-Lefevre, Sandrine H.; Voisin, Pascale [Institut de Radioprotection et de Surete Nucleaire (IRSN), DRPH, SRBE, LDB, BP17, 92262 Fontenay-aux-Roses (France); Gonzalez, Jorge E.; Lamadrid, Ana I.; Romero, Ivonne [Centro de Proteccion e Higiene de las Radiaciones, Calle 20 No. 4113 e/41y 47 Miramar, AP 6195 C. Habana (Cuba); Garcia, Omar, E-mail: omar@cphr.edu.cu [Centro de Proteccion e Higiene de las Radiaciones, Calle 20 No. 4113 e/41y 47 Miramar, AP 6195 C. Habana (Cuba); Voisin, Philippe; Roy, Laurence [Institut de Radioprotection et de Surete Nucleaire (IRSN), DRPH, SRBE, LDB, BP17, 92262 Fontenay-aux-Roses (France)

    2011-09-15

    Biological dosimeters are recommended for dose estimation in case of human overexposure to ionising radiation. Rapid measurement of {gamma}-H2AX foci as a marker of DNA double-strand breaks (DSB) induction has been recently tested with this purpose. Here we reported a dose-response relationship after X-ray irradiation at different times post-exposure. Blood samples were obtained from several healthy donors and exposed to doses between 0 and 2 Gy. After irradiation, blood samples were incubated at 37 deg. C during 0.5 h, 5 h, and 8 h. Scoring of cells and {gamma}-H2AX foci was performed by software. The dose-response curves for different incubation times were as follows: Y{sub (0.5h)} = 11.66D + 0.15 (R{sup 2} = 0.99), Y{sub (5h)} = 2.44D + 0.15 (R{sup 2} = 0.99), Y{sub (8h)} = 1.57D + 0.22 (R{sup 2} = 0.99). At 0.5 h post-exposure, the dose-response relationship for X-irradiated lymphocytes was similar to the one obtained after gamma-irradiation using the same protocol. On the other hand, the results were not similar after 8 h due to different kinetics after gamma- and X-irradiation. Our results confirm the possibilities of using {gamma}-H2AX foci method for dose estimation in a period from 0.5 h up to 8 h post X-irradiation and support the hypothesis of differences in {gamma}-H2AX foci kinetics after gamma- and X-irradiation in vitro.

  6. Dose-response relationships and risk estimates for the induction of cancer due to low doses of low-LET radiation

    International Nuclear Information System (INIS)

    Elaguppillai, V.

    1981-01-01

    Risk estimates for radiation-induced cancer at low doses can be obtained only by extrapolation from the known effects at high doses and high dose rates, using a suitable dose-response model. The applicability of three different models, linear, sublinear and supralinear, are discussed in this paper. Several experimental studies tend to favour a sublinear dose-response model (linear-quadratic model) for low-LET radiation. However, human epidemiological studies do not exclude any of the dose-response relationships. The risk estimates based on linear and linear quadratic dose-response models are compared and it is concluded that, for low-LET radiation, the linear dose-response model would probably over-estimate the actual risk of cancer by a factor of two or more. (author)

  7. Stage specificity and dose-response relationships for chromosome aberrations induced in mouse primary spermatocytes following X-irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Matsuda, Y.; Tobari, I.; Utsugi, T.

    1986-05-01

    In this study, dose-response relationships were examined for chromosome aberrations observed at diakinesis-metaphase I of spermatocytes with X-irradiation at various stages of meiosis (diplotene, mid-pachytene, zygotene and leptotene). The frequencies of cells with X-ray-induced chromosome aberrations increased with dose at all stages in the applied range of 0.5-3.0 Gy and tended to increase as the irradiated stages descended after leptotene stage. In three stages, the frequencies increased exponentially with dose, but the rates of induction of chromosome breaks were markedly different depending on the stages at which spermatocytes were irradiated with X-rays. The rate of induction was the highest at diplotene and the lowest at leptotene, suggesting that diplotene spermatocytes had the highest radiosensitivity to the induction of chromosome breaks, followed by pachytene, zygotene and leptotene spermatocytes in that order. The dose-response relationships fitted well to linear equations for deletion-type aberrations at each stage, and to linear-quadratic equations for exchange-type aberrations at all stages except for leptotene. At leptotene, the chromatid exchanges were hardly observed, the aberrations being mainly consisted of iso-chromatid fragments. On the contrary, chromatid exchanges and iso-chromatide deletions were mainly observed at later stages (zygotene-diplotene).

  8. Thyroid nodules in the population living around semipalatinsk nuclear test site. Possible implications for dose-response relationships study

    International Nuclear Information System (INIS)

    Zhumadilov, Z.

    2006-01-01

    The risk of radiation-induced nodules is higher than the risk for radiation-induced cancer. Risk factors and specific modifiers of the dose-response relationship may vary among different populations and not be well recognized. Many thyroid studies have considered thyroid nodularity itself, but not specific morphological types of thyroid nodules. There are many specific types of thyroid nodules which follow a morphological classification of thyroid lesions, including some congenital and tumor-like conditions. Modern equipment and technique can help us to identify particular specific types of thyroid nodules. In this study we report some results of a clinically applicable approach to materials derived from three studies. From 1999 through 2002, we have screened 571 current residents from 4 exposed and 1 control village near the Semipalatinsk Nuclear Test Site area, who were of similar ages (<20) at the time of major radiation fallout events at the Semipalatinsk Nuclear Test Site (SNTS). Prevalent nodules were identified by ultrasound and fine-needle aspiration biopsy, cytopathology results. Analysis of ultrasound images and cytopathology of thyroid lesions among exposed and non-exposed population allowed us to distinguish some interesting ultrasound features for specific types of thyroid nodules. We believe that it would be interesting and possibly more informative for thyroid dosimetry studies to consider specific morphological types of thyroid nodules. We need more detailed research to clarify the feasibility of applying these findings for study of the dose-response relationship. (author)

  9. A Threshold Exists in the Dose-response Relationship for Somatic Mutation Frequency Inducted by X-ray Irradiation of Drosophia

    International Nuclear Information System (INIS)

    Koana, T.; Takashima, Y.; Okada, M. O.; Ikehata, M.; Miyakoshi, J.; Sakai, K.

    2004-01-01

    The dose-response relationship of ionizing radiation and its stochastic effects has been thought to be linear without any thresholds. The basic data for this model was obtained from mutational assays in the male germ cells of fruits fly Drosophila melanogaster. However, carcinogenic activity should be examined more appropriately in somatic cells than in germ cells. Here, the dose-response relationship of X- ray irradiation and somatic mutation is examined in Drosophila. A threshold at approximately 1Gy was observed in the DNA repair proficient flies. In the repair deficient siblings, the threshold was smaller and the inclination of the dose-response curve was much steeper. These results suggest that the dose-response relationship between X-ray irradiation and somatic mutation has a threshold, and that the DNA repair function contributes to its formation. (Author) 35 refs

  10. Evaluation of the Comet Assay for Assessing the Dose-Response Relationship of DNA Damage Induced by Ionizing Radiation

    Science.gov (United States)

    Wang, Yan; Xu, Chang; Du, Li Qing; Cao, Jia; Liu, Jian Xiang; Su, Xu; Zhao, Hui; Fan, Fei-Yue; Wang, Bing; Katsube, Takanori; Fan, Sai Jun; Liu, Qiang

    2013-01-01

    Dose- and time-response curves were combined to assess the potential of the comet assay in radiation biodosimetry. The neutral comet assay was used to detect DNA double-strand breaks in lymphocytes caused by γ-ray irradiation. A clear dose-response relationship with DNA double-strand breaks using the comet assay was found at different times after irradiation (p < 0.001). A time-response relationship was also found within 72 h after irradiation (p < 0.001). The curves for DNA double-strand breaks and DNA repair in vitro of human lymphocytes presented a nice model, and a smooth, three-dimensional plane model was obtained when the two curves were combined. PMID:24240807

  11. Evaluation of the Comet Assay for Assessing the Dose-Response Relationship of DNA Damage Induced by Ionizing Radiation

    Directory of Open Access Journals (Sweden)

    Qiang Liu

    2013-11-01

    Full Text Available Dose- and time-response curves were combined to assess the potential of the comet assay in radiation biodosimetry. The neutral comet assay was used to detect DNA double-strand breaks in lymphocytes caused by γ-ray irradiation. A clear dose-response relationship with DNA double-strand breaks using the comet assay was found at different times after irradiation (p < 0.001. A time-response relationship was also found within 72 h after irradiation (p < 0.001. The curves for DNA double-strand breaks and DNA repair in vitro of human lymphocytes presented a nice model, and a smooth, three-dimensional plane model was obtained when the two curves were combined.

  12. Dose-response relationship analysis for cancer and circulatory system disease mortality risks among uranium miners

    International Nuclear Information System (INIS)

    Drubay, Damien

    2015-01-01

    The relation between lung cancer risk and radon exposure has been clearly established, especially from the studies on uranium miner cohorts. But the association between radon exposure and extrapulmonary cancers and non-cancer diseases remains not well known. Moreover, the health risks associated with the other mining-related ionizing radiation exposures are still under consideration. The aim of this thesis is to contribute to the estimation of the radio-induced health risks at low-doses through the analysis of the kidney cancer and Circulatory System Disease (CSD) mortality risks among uranium miners. Kidney cancer mortality risk analyses were performed from the French cohort of uranium miners (n=5086; follow-up period: 1946-2007), the post-55 cohort (n=3,377; follow-up period: 1957-2007) and the German cohort of the Wismut (n=58,986; follow-up period: 1946-2003) which included 24, 11 and 174 deaths from kidney cancer, respectively. The exposures to radon and its short-lived progeny (expressed in Working Level Month WLM), to uranium ore dust (kBqh.m -3 ) and to external gamma rays (mSv) were estimated for each miners and the equivalent kidney dose was calculated. The dose-response relation was refined considering two responses: the instantaneous risk of kidney cancer mortality (corresponding to the classical analysis, Cause specific Hazard Ratio (CSHR) estimated with the Cox model) and its occurrence probability during the followup (Sub-distribution Hazard Ratio (SHR) estimated with the Fine and Gray model). An excess of kidney cancer mortality was observed only in the French cohort (SMR = 1.62 CI95%[1.04; 2.41]). In the Wismut cohort, a decrease of the kidney cancer mortality was observed (0.89 [0.78; 0.99]). For these three cohorts, the occupational radiological exposures (or the equivalent kidney dose) were significantly associated neither with the risk of kidney cancer mortality (e.g. CSHRWismut-radon/100 WLM=1.023 [0.993; 1.053]), nor with its occurrence

  13. Determining the behavioural dose-response relationship of marine mammals to air gun noise and source proximity.

    Science.gov (United States)

    Dunlop, Rebecca A; Noad, Michael J; McCauley, Robert D; Scott-Hayward, Lindsay; Kniest, Eric; Slade, Robert; Paton, David; Cato, Douglas H

    2017-08-15

    The effect of various anthropogenic sources of noise (e.g. sonar, seismic surveys) on the behaviour of marine mammals is sometimes quantified as a dose-response relationship, where the probability of an animal behaviourally 'responding' (e.g. avoiding the source) increases with 'dose' (or received level of noise). To do this, however, requires a definition of a 'significant' response (avoidance), which can be difficult to quantify. There is also the potential that the animal 'avoids' not only the source of noise but also the vessel operating the source, complicating the relationship. The proximity of the source is an important variable to consider in the response, yet difficult to account for given that received level and proximity are highly correlated. This study used the behavioural response of humpback whales to noise from two different air gun arrays (20 and 140 cubic inch air gun array) to determine whether a dose-response relationship existed. To do this, a measure of avoidance of the source was developed, and the magnitude (rather than probability) of this response was tested against dose. The proximity to the source, and the vessel itself, was included within the one-analysis model. Humpback whales were more likely to avoid the air gun arrays (but not the controls) within 3 km of the source at levels over 140 re. 1 µPa 2  s -1 , meaning that both the proximity and the received level were important factors and the relationship between dose (received level) and response is not a simple one. © 2017. Published by The Company of Biologists Ltd.

  14. Dose-Response Relationship between Cumulative Occupational Lead Exposure and the Associated Health Damages: A 20-Year Cohort Study of a Smelter in China.

    Science.gov (United States)

    Wu, Yue; Gu, Jun-Ming; Huang, Yun; Duan, Yan-Ying; Huang, Rui-Xue; Hu, Jian-An

    2016-03-16

    Long-term airborne lead exposure, even below official occupational limits, has been found to cause lead poisoning at higher frequencies than expected, which suggests that China's existing occupational exposure limits should be reexamined. A retrospective cohort study was conducted on 1832 smelting workers from 1988 to 2008 in China. These were individuals who entered the plant and came into continuous contact with lead at work for longer than 3 months. The dose-response relationship between occupational cumulative lead exposure and lead poisoning, abnormal blood lead, urinary lead and erythrocyte zinc protoporphyrin (ZPP) were analyzed and the benchmark dose lower bound confidence limits (BMDLs) were calculated. Statistically significant positive correlations were found between cumulative lead dust and lead fumes exposures and workplace seniority, blood lead, urinary lead and ZPP values. A dose-response relationship was observed between cumulative lead dust or lead fumes exposure and lead poisoning (p lead dust and fumes doses were 0.68 mg-year/m³ and 0.30 mg-year/m³ for lead poisoning, respectively. The BMDLs of workplace airborne lead concentrations associated with lead poisoning were 0.02 mg/m³ and 0.01 mg/m³ for occupational exposure lead dust and lead fume, respectively. In conclusion, BMDLs for airborne lead were lower than occupational exposure limits, suggesting that the occupational lead exposure limits need re-examination and adjustment. Occupational cumulative exposure limits (OCELs) should be established to better prevent occupational lead poisoning.

  15. Nationwide Study of Humidifier Disinfectant Lung Injury in South Korea, 1994-2011. Incidence and Dose-Response Relationships.

    Science.gov (United States)

    Paek, Domyung; Koh, Younsuck; Park, Dong-Uk; Cheong, Hae-Kwan; Do, Kyung-Hyun; Lim, Chae-Man; Hong, Soo-Jong; Kim, Yong-Hwa; Leem, Jong-Han; Chung, Kyu Hyuck; Choi, Ye-Yong; Lee, Jong-Hyeon; Lim, Sin-Ye; Chung, Eun-Hee; Cho, Young Ah; Chae, Eun Jin; Joh, Joon-Sung; Yoon, Yup; Lee, Kyu-Hong; Choi, Bo Youl; Gwack, Jin

    2015-12-01

    Humidifier disinfectant lung injury is an acute lung disease attributed to recurrent inhalation of certain disinfectant aerosols emitted from room humidifiers. An outbreak of this toxic lung injury occurred in South Korea from 1995 until all humidifier disinfectant products were recalled from the consumer market by the government in 2011. A nationwide study was conducted to ascertain and classify all potential cases of humidifier disinfectant lung injury in Korea and to assess dose-response relationships. By several mechanisms, clinicians and the general public were invited to report all suspected cases of humidifier disinfectant lung injury to public health officials in South Korea. A committee was convened to define diagnostic criteria based on pathologic, radiologic, and clinical findings for index cases, combined with assessment of environmental exposure to humidifier disinfectants. Clinical review and environmental assessments were performed and later combined to determine overall likelihood of disease for each study participant, classified as definite, probable, possible, or unlikely. Survival time from exposure to onset of symptoms was analyzed to assess dose-response relationships. Three broad categories of risk factors were examined: (1) biological susceptibility, (2) temporal cycle of exposure and recovery, and (3) spatial conditions and density of disinfectant. Of 374 possible cases identified and reviewed, 329 were unanimously classified by the diagnostic committee, as follows: 117 definite, 34 probable, 38 possible and 140 unlikely cases. A total of 62 individuals with definite or probable disease died. Risk factors examined for polyhexamethyleneguanidine phosphate exposure that were found to be significant in shortening survival included age 4 years or younger at onset, use of disinfectant for 7 days per week, airborne density of 800 μg/m(3) or more of disinfectant, and daily exposure 11 or more hours in duration. Dose-response analysis indicated

  16. ESR signal features of 60Co γ-ray irradiated bone tissue and its dose response relationship

    International Nuclear Information System (INIS)

    Wu Ke; Sun Zunpu; Shi Yuanming

    1993-01-01

    Electron spin resonance (ESR) technique was used to study the radiation-induced ESR signal features of different paramagnetic species of 60 Co γ-ray irradiated bone tissue. The results showed that the intensity of an ESR signal at that the intensity of an ESR signal at g 2.0022 of human bones exposed to a dose range of 0-50 Gy had linear dose response relationships. The lower limit of detectable dose was about 2 Gy and the detecting error was about 10%. The signal was stable at room temperature during 60 days, and the effect of radiation dose rate of 0.5-8.0 Gy/min could be neglected. This signal was insensitive to microwave power and temperature, which was suitable for rapid and direct detection with ESR technique. These features suggest that human bones could be used for radiation accident dose evaluation by ESR

  17. On the existence of a threshold in the dose-response relationship from the epidemiological data of atomic bomb survivors

    International Nuclear Information System (INIS)

    Matsuura, Tatsuo; Sugahara, Tsutomu

    2002-01-01

    Whether or not there is a threshold dose in the dose-response relationship for cancer incidence due to radiation is one of the most important but controversial issues in radiation protection and nuclear policy making. The epidemiological studies on the Life Span Study (LSS) group of atomic bomb survivors in Hiroshima and Nagasaki, conducted by Radiation Effects Research Foundation (RERF) have been regarded to be most authentic, and they keep the view that there is no evidence to deny the linear non-threshold (LNT) hypotheses. The authors have claimed the necessity of reassessment of exposure doses of survivors, by considering the contribution of chronic dose, which comes from fall-out, induced radioactivity, and early entrance near the center of the city. The authors also have stressed the importance of the cases of if 'not-in-city' survivors, frequently reported to be fatal by the heavy chronic exposure. Recently we have noticed that the appearance of acute radiation symptoms is an important index for estimating total dose. In this paper, based on Obos statistical data (in 1957) for the acute symptoms observed for various category of survivors, we present an estimation of the average chronic dose of survivors, which should be added to the instantaneous dose for the directly exposed groups. By assuming the threshold for the appearance of the acute symptom such as epilation as 0.5 Sv, average chronic dose of 0.32 Sv was estimated for all survivors. Then the present dose-response relationship for cancer incidence should be shifted to the right hand side by this amount, and the value of about 0.32 Sv or more is suggested as the threshold for cancer incidence in low radiation level region

  18. Defining a dose-response relationship for prostate external beam radiotherapy

    International Nuclear Information System (INIS)

    Trada, Yuvnik; Plank, Ash; Martin, Jarad

    2013-01-01

    We aimed to quantify a relationship between radiotherapy dose and freedom from biochemical failure (FFBF) in low- and intermediate-risk prostate cancer. To reduce confounding we used data with a standardised end–point, mature follow-up, low competing risk of metastatic failure, conventional fractionation and separate reporting for outcomes with hormonal therapy (HT). A systematic review of the literature was carried out. Studies that reported the use of radiotherapy alone in 1.8–2Gy fractions in low- and intermediate-risk prostate cancer were included. The primary end–point was Phoenix definition 5-year FFBF. A logistic regression was used to quantify the dose–response relationship. Data from eight studies with 3037 patients met the inclusion criteria. The data from 810 low-risk patients and 2245 intermediate-risk patients were analysed. A strong association between radiotherapy dose and FFBF was found in low- and intermediate-risk patients managed with radiotherapy alone. In low-risk patients not treated with HT the dose required to achieve 50% biochemical tumour control (TCD 50 ) is 52.0 Gy and the slope of the dose–response curve at TCD 50 (γ 50 ) is 2.1%/Gy. At 78Gy this represented a FFBF of 90.3%. In intermediate-risk patients not treated with HT the TCD 50 is 64.7Gy and γ 50 is 3.2%/Gy. At 78 Gy this translated into a FFBF of 84.3%. HT had a small effect for low-risk patients and an inconsistent effect for intermediate-risk men. A strong association was found between radiation dose and biochemical outcome in both low- and intermediate-risk patients. Standardised reporting of results from future studies will make future analyses more robust.

  19. Prenatal irradiation and spatial memory in mice: investigation of dose-response relationship

    International Nuclear Information System (INIS)

    Sienkiewicz, Z.J.; Haylock, R.G.E.; Saunders, R.D.

    1994-01-01

    Pregnant CD1 mice were exposed on gestational day 18 to 250 kV X-rays at 0.1, 0.25, 0.35 and 0.5 Gy. The performances of 10 adult male offspring from each exposure condition were investigated on a spatial discrimination learning task in a radial arm maze. An impairment in the performance of this task was found which showed a correlation with dose. Compared with sham exposed control mice, performance was not significantly affected with irradiation at 0.1 Gy and was slightly but non-significantly reduced at 0.25 Gy. Irradiation at 0.35 Gy caused a significant impairment in performance, and exposure at 0.5 Gy resulted in a still larger impairment. The overall association between dose and behavioural impairment was best described by a linear relationship without a threshold, although at doses lower than about 0.25 Gy any impairment would appear to be too small to be detectable. (Author)

  20. Exposure dose response relationships of the freshwater bivalve Hyridella australis to cadmium spiked sediments

    International Nuclear Information System (INIS)

    Marasinghe Wadige, Chamani P.M.; Maher, William A.; Taylor, Anne M.; Krikowa, Frank

    2014-01-01

    Highlights: • The exposure–dose–response approach was used to assess cadmium exposure and toxicity. • Accumulated cadmium in H. australis reflected the sediment cadmium exposure. • Spill over of cadmium into the biologically active pool was observed. • Increased cadmium resulted in measurable biological effects. • H. australis has the potential to be a cadmium biomonitor in freshwater environments. - Abstract: To understand how benthic biota may respond to the additive or antagonistic effects of metal mixtures in the environment it is first necessary to examine their responses to the individual metals. In this context, laboratory controlled single metal-spiked sediment toxicity tests are useful to assess this. The exposure–dose–response relationships of Hyridella australis to cadmium-spiked sediments were, therefore, investigated in laboratory microcosms. H. australis was exposed to individual cadmium spiked sediments (<0.05 (control), 4 ± 0.3 (low) and 15 ± 1 (high) μg/g dry mass) for 28 days. Dose was measured as cadmium accumulation in whole soft body and individual tissues at weekly intervals over the exposure period. Dose was further examined as sub-cellular localisation of cadmium in hepatopancreas tissues. The biological responses in terms of enzymatic and cellular biomarkers were measured in hepatopancreas tissues at day 28. H. australis accumulated cadmium from spiked sediments with an 8-fold (low exposure organisms) and 16-fold (high exposure organisms) increase at day 28 compared to control organisms. The accumulated tissue cadmium concentrations reflected the sediment cadmium exposure at day 28. Cadmium accumulation in high exposure organisms was inversely related to the tissue calcium concentrations. Gills of H. australis showed significantly higher cadmium accumulation than the other tissues. Accumulated cadmium in biologically active and biologically detoxified metal pools was not significantly different in cadmium exposed

  1. The Hematopoietic Syndrome of the Acute Radiation Syndrome in Rhesus Macaques: A Systematic Review of the Lethal Dose Response Relationship.

    Science.gov (United States)

    MacVittie, Thomas J; Farese, Ann M; Jackson, William

    2015-11-01

    Well characterized animal models that mimic the human response to potentially lethal doses of radiation are required to assess the efficacy of medical countermeasures under the criteria of the U.S. Food and Drug Administration "animal rule." Development of a model requires the determination of the radiation dose response relationship and time course of mortality and morbidity across the hematopoietic acute radiation syndrome. The nonhuman primate, rhesus macaque, is a relevant animal model that may be used to determine the efficacy of medical countermeasures to mitigate major signs of morbidity and mortality at selected lethal doses of total body irradiation. A systematic review of relevant studies that determined the dose response relationship for the hematopoietic acute radiation syndrome in the rhesus macaque relative to radiation quality, dose rate, and exposure uniformity has never been performed. The selection of data cohorts was made from the following sources: Ovid Medline (1957-present), PubMed (1954-present), AGRICOLA (1976-present), Web of Science (1954-present), and U.S. HHS REPORT (2002 to present). The following terms were used: Rhesus, total body-irradiation, total body x irradiation, TBI, irradiation, gamma radiation, hematopoiesis, LD50/60, Macaca mulatta, whole-body irradiation, nonhuman primate, NHP, monkey, primates, hematopoietic radiation syndrome, mortality, and nuclear radiation. The reference lists of all studies, published and unpublished, were reviewed for additional studies. The total number of hits across all search sites was 3,001. There were a number of referenced, unpublished, non-peer reviewed government reports that were unavailable for review. Fifteen studies, 11 primary (n = 863) and four secondary (n = 153) studies [n = 1,016 total nonhuman primates (NHP), rhesus Macaca mulatta] were evaluated to provide an informative and consistent review. The dose response relationships (DRRs) were determined for uniform or non-uniform total

  2. Dose response relationship of disturbed migration of Purkinje cells in the cerebellum due to X-irradiation

    International Nuclear Information System (INIS)

    Darmanto, W.; Inouye, Minoru; Hayasaka, Shizu; Takagishi, Yoshiko; Aolad, H.; Murata, Yoshiharu

    1998-01-01

    Pregnant rats were exposed to 2.0, 2.25 or 2.5 Gy X-irradiation on gestation day 21. Pups were sacrificed 12 hr after exposure, and on postnatal day 5 (P5), P7 and P9. Their cerebella were observed immunohistochemically using anti-inositol 1,4,5 triphosphate (IP3) receptor antibody to identify Purkinje cells. These cells were disturbed to migrate and remained in the internal granular layer and white matter of the cerebellum. They had short dendrites, and some showed an abnormal direction of dendrites in rats exposed to 2.25 or 2.5 Gy. Alignment of Purkinje cells was also disturbed when examined either on P5, P7 or P9 especially by doses of 2.25 and 2.5 Gy. There was a relationship between X-ray doses and the number of cells piling up in the Purkinje cell layer of the cerebellum. The dose-response relationship with the number of ectopic Purkinje cells was noted in the anterior lobes of the cerebellum. (author)

  3. Work-related symptoms and dose-response relationships for personal exposures and pulmonary function among woodworkers.

    Science.gov (United States)

    Mandryk, J; Alwis, K U; Hocking, A D

    1999-05-01

    Four sawmills, a wood chipping mill, and five joineries in New South Wales, Australia, were studied for the effects of personal exposure to wood dust, endotoxins. (1-->3)-beta-D-glucans, Gram-negative bacteria, and fungi on lung function among woodworkers. Personal inhalable and respirable dust sampling was carried out. The lung function tests of workers were conducted before and after a workshift. The mean percentage cross-shift decrease in lung function was markedly high for woodworkers compared with the controls. Dose-response relationships among personal exposures and percentage cross-shift decrease in lung function and percentage predicted lung function were more pronounced among joinery workers compared with sawmill and chip mill workers. Woodworkers had markedly high prevalence of regular cough, phlegm, and chronic bronchitis compared with controls. Significant associations were found between percentage cross-shift decrease in FVC and regular phlegm and blocked nose among sawmill and chip mill workers. Both joinery workers and sawmill and chip mill workers showed significant relationships between percentage predicted lung function (FVC, FEV1, FEV1/FVC, FEF25-75%) and respiratory symptoms. Wood dust and biohazards associated with wood dust are potential health hazards and should be controlled.

  4. ESTIMATING A DOSE-RESPONSE RELATIONSHIP BETWEEN LENGTH OF STAY AND FUTURE RECIDIVISM IN SERIOUS JUVENILE OFFENDERS*

    Science.gov (United States)

    Loughran, Thomas A.; Mulvey, Edward P.; Schubert, Carol A.; Fagan, Jeffrey; Piquero, Alex R.; Losoya, Sandra H.

    2009-01-01

    The effect of sanctions on subsequent criminal activity is of central theoretical importance in criminology. A key question for juvenile justice policy is the degree to which serious juvenile offenders respond to sanctions and/or treatment administered by the juvenile court. The policy question germane to this debate is finding the level of confinement within the juvenile justice system that maximizes the public safety and therapeutic benefits of institutional confinement. Unfortunately, research on this issue has been limited with regard to serious juvenile offenders. We use longitudinal data from a large sample of serious juvenile offenders from two large cities to 1) estimate a causal treatment effect of institutional placement, as opposed to probation, on future rate of rearrest and 2) investigate the existence of a marginal effect (i.e., benefit) for longer length of stay once the institutional placement decision had been made. We accomplish the latter by determining a dose-response relationship between the length of stay and future rates of rearrest and self-reported offending. The results suggest that an overall null effect of placement exists on future rates of rearrest or self-reported offending for serious juvenile offenders. We also find that, for the group placed out of the community, it is apparent that little or no marginal benefit exists for longer lengths of stay. Theoretical, empirical, and policy issues are outlined. PMID:20052309

  5. Dose-response relationship of the cardiovascular adaptation to endurance training in healthy adults: how much training for what benefit?

    Science.gov (United States)

    Iwasaki, Ken-Ichi; Zhang, Rong; Zuckerman, Julie H; Levine, Benjamin D

    2003-10-01

    Occupational or recreational exercise reduces mortality from cardiovascular disease. The potential mechanisms for this reduction may include changes in blood pressure (BP) and autonomic control of the circulation. Therefore, we conducted the present long-term longitudinal study to quantify the dose-response relationship between the volume and intensity of exercise training, and regulation of heart rate (HR) and BP. We measured steady-state hemodynamics and analyzed dynamic cardiovascular regulation by spectral and transfer function analysis of cardiovascular variability in 11 initially sedentary subjects during 1 yr of progressive endurance training sufficient to allow them to complete a marathon. From this, we found that 1) moderate exercise training for 3 mo decreased BP, HR, and total peripheral resistance, and increased cardiovascular variability and arterial baroreflex sensitivity; 2) more prolonged and intense training did not augment these changes further; and 3) most of these changes returned to control values at 12 mo despite markedly increased training duration and intensity equivalent to that routinely observed in competitive athletes. In conclusion, increases in R-wave-R-wave interval and cardiovascular variability indexes are consistent with an augmentation of vagal modulation of HR after exercise training. It appears that moderate doses of training for 3 mo are sufficient to achieve this response as well as a modest hypotensive effect from decreasing vascular resistance. However, more prolonged and intense training does not necessarily lead to greater enhancement of circulatory control and, therefore, may not provide an added protective benefit via autonomic mechanisms against death by cardiovascular disease.

  6. Factors that determine the in vivo dose-response relationship for stable chromosome aberrations in A-bomb survivors

    International Nuclear Information System (INIS)

    Awa, A.A.; Nakano, Mimako; Ohtaki, Kazuo; Kodama, Yoshiaki; Lucas, J.; Gray, J.

    1992-01-01

    An overview is given of the dose-response relationship for stable chromosome aberrations (i.e., translocations and inversions) in the peripheral blood lymphocytes of A-bomb survivors in Hiroshima. Special emphasis is placed on (i) the overdispersion of survivor cases with either unexpectedly high or low aberration frequencies relative to the estimated DS86 kerma values assigned to individual survivors, termed 'cytogenetic outliers', and (ii) the correlation of chromosome aberration frequencies with other biological endpoints, such as acute radiation symptoms (severe epilation). A new molecular biological technique, known as fluorescence in situ hybridization (FISH) with composite, whole-chromosome probes to paint differentially the target chromosomes, has facilitated rapid, efficient, and extensive scoring of translocation-type chromosome aberrations in which the target chromosomes are involved. Using this methodology, the observed findings on translocation frequencies in A-bomb survivors have shown that the frequency of stable chromosome aberrations, which have persisted for years without change in frequency in irradiated persons, is indeed useful as an indicator for biological dosimetry. (author)

  7. Effects of single-shot and steady-state propofol anaesthesia on rocuronium dose-response relationship: a randomised trial.

    Science.gov (United States)

    Stäuble, C G; Stäuble, R B; Schaller, S J; Unterbuchner, C; Fink, H; Blobner, M

    2015-08-01

    Similar to volatile anaesthetics, propofol may influence neuromuscular transmission. We hypothesised that the administration of propofol influenced the potency of rocuronium depending on the duration of the administration. After consent, patients scheduled for elective surgery randomly received rocuronium either after induction of anaesthesia with propofol (2 min of propofol, n = 36) or after 30 min of propofol infusion (30 min of propofol, n = 36). Remifentanil was given in both groups. Neuromuscular monitoring was performed by calibrated electromyography. The dose-response relationship of rocuronium was determined with a single-bolus technique (0.07, 0.1, 0.15, 0.2, 0.3 and 0.45 mg/kg rocuronium). The primary endpoints were the ED50 and ED95 of rocuronium after 2 and 30 min propofol. Data are presented as means with (95% confidence interval). The trial is registered with the Eudra-CT: 2009-012815-16. A total of 72 patients were included. Time to maximal neuromuscular blockade was significantly shorter in patients after 30 min of propofol [3.3 min (2.9-3.7)] compared with patients anaesthetised with 2 min of propofol [4.6 min (4.0-5.2)]. After 30 min of propofol, the slope of the dose-response curve was significantly steeper (30 min of propofol: 4.34 [3.62-5.05]; 2 min of propofol: [3.34 (2.72-3.96)], resulting in lower ED95 values of rocuronium (30 min of propofol: 0.287 mg/kg [0.221-0.368]; 2 min of propofol [0.391 mg/kg (0.296-0.520)]. The ED50 were not different between groups. The potency of rocuronium was significantly enhanced after propofol infusion for 30 min. Estimates of potency those are usually determined during steady-state anaesthesia might underestimate rocuronium requirements for endotracheal intubation at the time of induction. © 2015 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  8. Systematic review using meta-analyses to estimate dose-response relationships between iodine intake and biomarkers of iodine status in different population groups

    NARCIS (Netherlands)

    Ristic-Medic, D.; Dullemeijer, C.; Tepsic, J.; Petrovic-Oggiano, G.; Popovic, Z.; Arsic, A.; Glibetic, M.; Souverein, O.W.; Collings, R.; Cavelaars, A.J.E.M.; Groot, de C.P.G.M.; Veer, van 't P.; Gurinovic, M.

    2014-01-01

    The objective of this systematic review was to identify studies investigating iodine intake and biomarkers of iodine status, to assess the data of the selected studies, and to estimate dose-response relationships using meta-analysis. All randomized controlled trials, prospective cohort studies,

  9. A dose-response relationship between long working hours and unmet need for access to hospital facilities.

    Science.gov (United States)

    Soek, Hongdeok; Won, Jong-Uk; Lee, Tae Il; Kim, Yeong-Kwang; Lee, Wanhyung; Lee, June-Hee; Roh, Jaehoon; Yoon, Jin-Ha

    2016-03-01

    Lack of access to hospital facilities, indicating unmet healthcare need, plays an important role in health inequity in the workplace. We aimed to investigate the association between long working hours and unmet healthcare need. We used data from the Korea National Health and Nutrition Examination Surveys collected during 2007-2012, which included 8369 participants (4765 males, 3604 females) aged 20-54 years, who were paid workers. We used a logistic regression model with gender stratification to investigate the association between working hours and unmet healthcare need. Of the 8369 participants, 855 males (17.94%) and 981 females (27.22%) experienced unmet healthcare need. After adjusting for covariates, and compared to 30-39 working hours per week, the odds ratios (OR) of unmet healthcare need were 1.07 [(95% confidence interval (95% CI) 0.76-1.51], 1.46 (95% CI 1.03-2.07), and 1.57 (95% CI 1.11-2.23) in males, and 1.13 (95% CI 0.92-1.40), 1.30 (95% CI 0.99-1.69), and 1.60 (95% CI 1.21-2.10) in females, for 40-49, 50-59, and ≥ 60 work hours per week, respectively. There was a dose-response relationship between working hours per week and unmet healthcare need in both genders. Those who work long hours are more likely to have unmet healthcare needs, the cause of which seems to be lack of time.

  10. Quantitative radiation dose-response relationships for normal tissues in man. II. Response of the salivary glands during radiotherapy

    International Nuclear Information System (INIS)

    Mossman, K.L.

    1983-01-01

    A quantitative dose-response curve for salivary gland function in patients during radiotherapy is presented. Salivary-function data used in this study were obtained from four previously published reports. All patients were treated with 60 Co teletherapy to the head and neck using conventional treatment techniques. Salivary dysfunction was determined at specific dose levels by comparing salivary flow rates before therapy with flow rates at specific dose intervals during radiotherapy up to a total dose of 6000 cGy. Fifty percent salivary dysfunction occurred after 1000 cGy and eighty percent dysfunction was observed by the end of the therapy course (6000 cGy). The salivary-function curve was also compared to the previously published dose-response curve for taste function. Comparisons of the two curves indicate that salivary dysfunction precedes taste loss and that the shapes of the dose-response curves are different. A new term, tissue tolerance ratio, defined as the ratio of responses of two tissues given the same radiation dose, was used to make the comparisons between gustatory and salivary gland tissue effects. Measurements of salivary gland function and analysis of dose-response curves may be useful in evaluating chemical modifiers of radiation response

  11. Dose-Response Relationship between Dietary Magnesium Intake and Risk of Type 2 Diabetes Mellitus: A Systematic Review and Meta-Regression Analysis of Prospective Cohort Studies

    Directory of Open Access Journals (Sweden)

    Xin Fang

    2016-11-01

    Full Text Available The epidemiological evidence for a dose-response relationship between magnesium intake and risk of type 2 diabetes mellitus (T2D is sparse. The aim of the study was to summarize the evidence for the association of dietary magnesium intake with risk of T2D and evaluate the dose-response relationship. We conducted a systematic review and meta-analysis of prospective cohort studies that reported dietary magnesium intake and risk of incident T2D. We identified relevant studies by searching major scientific literature databases and grey literature resources from their inception to February 2016. We included cohort studies that provided risk ratios, i.e., relative risks (RRs, odds ratios (ORs or hazard ratios (HRs, for T2D. Linear dose-response relationships were assessed using random-effects meta-regression. Potential nonlinear associations were evaluated using restricted cubic splines. A total of 25 studies met the eligibility criteria. These studies comprised 637,922 individuals including 26,828 with a T2D diagnosis. Compared with the lowest magnesium consumption group in the population, the risk of T2D was reduced by 17% across all the studies; 19% in women and 16% in men. A statistically significant linear dose-response relationship was found between incremental magnesium intake and T2D risk. After adjusting for age and body mass index, the risk of T2D incidence was reduced by 8%–13% for per 100 mg/day increment in dietary magnesium intake. There was no evidence to support a nonlinear dose-response relationship between dietary magnesium intake and T2D risk. The combined data supports a role for magnesium in reducing risk of T2D, with a statistically significant linear dose-response pattern within the reference dose range of dietary intake among Asian and US populations. The evidence from Europe and black people is limited and more prospective studies are needed for the two subgroups.

  12. The incidence of radioepidermitis and the dose-response relationship in parotid gland cancer patients treated with 125I seed brachytherapy. Incidence of radioepidermitis and the dose-response relationship

    Energy Technology Data Exchange (ETDEWEB)

    Mao, Ming-Hui; Zheng, Lei; Gao, Hong; Zhang, Jie; Liu, Shu-ming; Huang, Ming-wei; Shi, Yan [Peking University School and Hospital of Stomatology, Department of Oral and Maxillofacial Surgery, Beijing (China); Zhang, Jian-Guo [Peking University School and Hospital of Stomatology, Department of Oral and Maxillofacial Surgery, Beijing (China); Fujian Provincial Hospital, Fujian (China)

    2014-09-09

    We studied the incidence and dose-response relationship of radioepidermitis in parotid gland carcinoma patients treated with [{sup 125}I] seed brachytherapy in the hopes of designing an optimized pre-implant treatment plan that would reduce the incidence and severity of radioepidermitis in patients receiving this therapy. Between January 2007 and May 2010, 100 parotid gland cancer patients were treated postoperatively with [{sup 125}I] seed brachytherapy. The matched peripheral dose (MPD) was 80-140 Gy, and [{sup 125}I] seed activity was 0.7-0.8 mCi. The mean dose delivered to the skin was calculated in the post-implant CT on day 0 following implantation. Grades of acute and late dermatitis were evaluated at 2, 6, 12, and 18 months post-implantation. Most patients experienced grade 0-2 acute and late skin side effects (86 and 97 %, respectively), though a small subset developed severe complications. Most grade 1-3 effects resolved within 6 months of implantation, though some grade 1-3 effects and all grade 4 effects remained unchanged throughout the 18-month follow-up period. Grade 3 and 4 effects were most prominent (75 and 25 %, respectively) with doses of 110-140 Gy; doses higher than 140 Gy produced only grade 4 effects. [{sup 125}I] seed brachytherapy produced acceptable levels of acute and late radioepidermitis with a good clinical outcome. A mean dose under 100 Gy delivered to the skin was safe, though doses of 110-140 Gy should be given with caution and extra monitoring; doses greater than 140 Gy are dangerous and likely to produce grade 4-5 effects. (orig.) [German] Wir untersuchten die Inzidenz und die Dosis-Wirkung-Beziehung bei Patienten mit Ohrspeicheldruesenkrebs, die mit [{sup 125}I]-Seed-Brachytherapie behandelt wurden, in der Hoffnung, eine optimierte praeimplantologische Behandlung zu entwickeln, welche die Inzidenz und Schwere der Radioepidermitis bei Patienten, die diese Therapie erhalten haben, reduziert. Zwischen Januar 2007 und Mai 2010

  13. The six year report: Acidification of surface water in Europe and North America. Dose/response relationships and long-term trends

    Energy Technology Data Exchange (ETDEWEB)

    Skjelkvaale, B L; Newell, A D; Raddum, G; Johannessen, M; Hovind, H; Tjomsland, T; Wathne, B M

    1994-12-31

    This report discusses The International Cooperative Programme on Assessment and Monitoring of Acidification of Rivers and Lakes, which is designed to (1) establish degree and extent of acidification of surface waters, (2) evaluate dose/response relationships and (3) define long-term trends and variations in aquatic chemistry and biota attributable to atmospheric pollution. Data from 200 sites in 14 countries of Europe and North America are available. Dose/response relationships show that the fauna is adapted to different water qualities in different regions, and that critical limits for the fauna must be calculated according to data for the specific region. Long-term trends of water chemistry show decreases in SO{sub 4}{sup 2-} and Ca{sup 2+} at many sites. Nitrate shows no consistent trends. 66 refs., 26 figs., 16 tabs.

  14. Dose-response relationship for chromosomal aberrations induced in human lymphocytes by 18 MeV electron beam irradiation

    International Nuclear Information System (INIS)

    Lashin, E.A.; Elaasar, E.M.; Moustafa, H.F.; Bakir, Y.Y.; Al Zenki, S.D.

    1990-01-01

    Dose response curves for lymphocyte chromosome aberration frequencies using X- and gamma radiation became an important and reliable indicator as biological dosimeter especially in radiation accidents and occupational over exposures. Nowadays electron beam therapy is frequently used for their advantages in cases of tumours under or near to the body surface. Dose-response curves for these electron beams are rarely published. Human peripheral blood lymphocytes were in vitro irradiated with various low and high doses (0.1 Gy to 4.9 Gy) of 18 MeV electron beams to utilize such a dose-response curve using chromosomal aberration frequencies as a biological indicator. Then we compared the biological curve with physically obtained curves normally used in planning for radiotherapy treatment. It is interesting to find a significant difference between both of them. The biological curve is generally higher in value and the aberrations induced by 93% of a dose is significantly higher and deeper in site than those aberrations induced by the 100% dose calculated physically. If the above observation is confirmed by detailed studies, it would be of importance to the radiotherapist to plan for isodose curves according to biological determinations. (author)

  15. Dose-response relationship for life-shortening and carcinogenesis in mice irradiated at day 7 postnatal age with dose range below 1 Gy of gamma rays

    International Nuclear Information System (INIS)

    Sasaki, Shunsaku; Fukuda, Nobuo

    2006-01-01

    This study was designed to elucidate the dose-response relationships for life-shortening and tumorigenic effect in the dose range below 1 Gy of gamma rays delivered during the infant period. Female B6C3F 1 mice were irradiated with 0.10, 0.48 or 0.95 Gy at 7 days of age. All irradiated mice were allowed to live out their entire life span together with a simultaneously ongoing control group under a specific pathogen-free condition. Shortening of the mean life span was 1.58% in mice irradiated with 0.10 Gy, which was statistically significant. The coefficient of the linear dose-response relationship for life-shortening was 11.21% Gy -1 . The attributable death fraction for all causes of death in 0.10 Gy group reached 0.092. The excess relative risk for death rate from all causes was 0.102 in the group irradiated with 0.10 Gy. The coefficient of the linear dose-response relationship of the excess relative risk for death rate from all causes was 1.30 Gy -1 . The mean number of types of solid tumors at the time of death in mice irradiated with 0.10 Gy was distinctly larger than that in the control group. The excess relative risk for death rate from solid tumors was 0.45 in mice irradiated with 0.10 Gy. The coefficient of the linear dose-response relationship of excess relative risk for death rate from solid tumors was 4.52 Gy -1 . Increase in incidences of the pituitary, ovarian and adrenal tumors was observed in mice irradiated with 0.10 Gy. The results of the present study showed that infant mice are susceptible to solid tumor induction, especially of the endocrine organs. (author)

  16. Dose-Response Relationship between Cumulative Occupational Lead Exposure and the Associated Health Damages: A 20-Year Cohort Study of a Smelter in China

    OpenAIRE

    Yue Wu; Jun-Ming Gu; Yun Huang; Yan-Ying Duan; Rui-Xue Huang; Jian-An Hu

    2016-01-01

    Long-term airborne lead exposure, even below official occupational limits, has been found to cause lead poisoning at higher frequencies than expected, which suggests that China’s existing occupational exposure limits should be reexamined. A retrospective cohort study was conducted on 1832 smelting workers from 1988 to 2008 in China. These were individuals who entered the plant and came into continuous contact with lead at work for longer than 3 months. The dose-response relationship between o...

  17. The influence of tube voltage and phantom size in computed tomography on the dose-response relationship of dicentrics in human blood samples

    International Nuclear Information System (INIS)

    Jost, G; Pietsch, H; Lengsfeld, P; Voth, M; Schmid, E

    2010-01-01

    The aim of this study was to investigate the dose response relationship of dicentrics in human lymphocytes after CT scans at tube voltages of 80 and 140 kV. Blood samples from a healthy donor placed in tissue equivalent abdomen phantoms of standard, pediatric and adipose sizes were exposed at dose levels up to 0.1 Gy using a 64-slice CT scanner. It was found that both the tube voltage and the phantom size significantly influenced the CT scan-induced linear dose-response relationship of dicentrics in human lymphocytes. Using the same phantom (standard abdomen), 80 kV CT x-rays were biologically more effective than 140 kV CT x-rays. However, it could also be determined that the applied phantom size had much more influence on the biological effectiveness. Obviously, the increasing slopes of the CT scan-induced dose response relationships of dicentrics in human lymphocytes obtained in a pediatric, a standard and an adipose abdomen have been induced by scattering effects of photons, which strongly increase with increasing phantom size.

  18. Systematic review using meta-analyses to estimate dose-response relationships between iodine intake and biomarkers of iodine status in different population groups.

    Science.gov (United States)

    Ristić-Medić, Danijela; Dullemeijer, Carla; Tepsić, Jasna; Petrović-Oggiano, Gordana; Popović, Tamara; Arsić, Aleksandra; Glibetić, Marija; Souverein, Olga W; Collings, Rachel; Cavelaars, Adriënne; de Groot, Lisette; van't Veer, Pieter; Gurinović, Mirjana

    2014-03-01

    The objective of this systematic review was to identify studies investigating iodine intake and biomarkers of iodine status, to assess the data of the selected studies, and to estimate dose-response relationships using meta-analysis. All randomized controlled trials, prospective cohort studies, nested case-control studies, and cross-sectional studies that supplied or measured dietary iodine and measured iodine biomarkers were included. The overall pooled regression coefficient (β) and the standard error of β were calculated by random-effects meta-analysis on a double-log scale, using the calculated intake-status regression coefficient (β) for each individual study. The results of pooled randomized controlled trials indicated that the doubling of dietary iodine intake increased urinary iodine concentrations by 14% in children and adolescents, by 57% in adults and the elderly, and by 81% in pregnant women. The dose-response relationship between iodine intake and biomarkers of iodine status indicated a 12% decrease in thyroid-stimulating hormone and a 31% decrease in thyroglobulin in pregnant women. The model of dose-response quantification used to describe the relationship between iodine intake and biomarkers of iodine status may be useful for providing complementary evidence to support recommendations for iodine intake in different population groups.

  19. The influence of tube voltage and phantom size in computed tomography on the dose-response relationship of dicentrics in human blood samples

    Energy Technology Data Exchange (ETDEWEB)

    Jost, G; Pietsch, H [TRG Diagnostic Imaging, Bayer Schering Pharma AG, Berlin (Germany); Lengsfeld, P; Voth, M [Global Medical Affairs Diagnostic Imaging, Bayer Schering Pharma AG, Berlin (Germany); Schmid, E, E-mail: Ernst.Schmid@lrz.uni-muenchen.d [Institute for Cell Biology, Center for Integrated Protein Science, University of Munich (Germany)

    2010-06-07

    The aim of this study was to investigate the dose response relationship of dicentrics in human lymphocytes after CT scans at tube voltages of 80 and 140 kV. Blood samples from a healthy donor placed in tissue equivalent abdomen phantoms of standard, pediatric and adipose sizes were exposed at dose levels up to 0.1 Gy using a 64-slice CT scanner. It was found that both the tube voltage and the phantom size significantly influenced the CT scan-induced linear dose-response relationship of dicentrics in human lymphocytes. Using the same phantom (standard abdomen), 80 kV CT x-rays were biologically more effective than 140 kV CT x-rays. However, it could also be determined that the applied phantom size had much more influence on the biological effectiveness. Obviously, the increasing slopes of the CT scan-induced dose response relationships of dicentrics in human lymphocytes obtained in a pediatric, a standard and an adipose abdomen have been induced by scattering effects of photons, which strongly increase with increasing phantom size.

  20. Dose-response relationship of physical activity to premature and total all-cause and cardiovascular disease mortality in walkers.

    Directory of Open Access Journals (Sweden)

    Paul T Williams

    Full Text Available PURPOSE: To assess the dose-response relationships between cause-specific mortality and exercise energy expenditure in a prospective epidemiological cohort of walkers. METHODS: The sample consisted of the 8,436 male and 33,586 female participants of the National Walkers' Health Study. Walking energy expenditure was calculated in metabolic equivalents (METs, 1 MET = 3.5 ml O2/kg/min, which were used to divide the cohort into four exercise categories: category 1 (≤ 1.07 MET-hours/d, category 2 (1.07 to 1.8 MET-hours/d, category 3 (1.8 to 3.6 MET-hours/d, and category 4 (≥ 3.6 MET-hours/d. Competing risk regression analyses were use to calculate the risk of mortality for categories 2, 3 and 4 relative to category 1. RESULTS: 22.9% of the subjects were in category 1, 16.1% in category 2, 33.3% in category 3, and 27.7% in category 4. There were 2,448 deaths during the 9.6 average years of follow-up. Total mortality was 11.2% lower in category 2 (P = 0.04, 32.4% lower in category 3 (P<10(-12 and 32.9% lower in category 4 (P = 10(-11 than in category 1. For underlying causes of death, the respective risk reductions for categories 2, 3 and 4 were 23.6% (P = 0.008, 35.2% (P<10(-5, and 34.9% (P = 0.0001 for cardiovascular disease mortality; 27.8% (P = 0.18, 20.6% (P = 0.07, and 31.4% (P = 0.009 for ischemic heart disease mortality; and 39.4% (P = 0.18, 63.8% (P = 0.005, and 90.6% (P = 0.002 for diabetes mortality when compared to category 1. For all related mortality (i.e., underlying and contributing causes of death combined, the respective risk reductions for categories 2, 3 and 4 were 18.7% (P = 0.22, 42.5% (P = 0.001, and 57.5% (P = 0.0001 for heart failure; 9.4% (P = 0.56, 44.3% (P = 0.0004, and 33.5% (P = 0.02 for hypertensive diseases; 11.5% (P = 0.38, 41.0% (P<10(-4, and 35.5% (P = 0.001 for dysrhythmias: and 23.2% (P = 0.13, 45.8% (P = 0.0002, and 41.1% (P

  1. An update on modeling dose-response relationships: Accounting for correlated data structure and heterogeneous error variance in linear and nonlinear mixed models.

    Science.gov (United States)

    Gonçalves, M A D; Bello, N M; Dritz, S S; Tokach, M D; DeRouchey, J M; Woodworth, J C; Goodband, R D

    2016-05-01

    Advanced methods for dose-response assessments are used to estimate the minimum concentrations of a nutrient that maximizes a given outcome of interest, thereby determining nutritional requirements for optimal performance. Contrary to standard modeling assumptions, experimental data often present a design structure that includes correlations between observations (i.e., blocking, nesting, etc.) as well as heterogeneity of error variances; either can mislead inference if disregarded. Our objective is to demonstrate practical implementation of linear and nonlinear mixed models for dose-response relationships accounting for correlated data structure and heterogeneous error variances. To illustrate, we modeled data from a randomized complete block design study to evaluate the standardized ileal digestible (SID) Trp:Lys ratio dose-response on G:F of nursery pigs. A base linear mixed model was fitted to explore the functional form of G:F relative to Trp:Lys ratios and assess model assumptions. Next, we fitted 3 competing dose-response mixed models to G:F, namely a quadratic polynomial (QP) model, a broken-line linear (BLL) ascending model, and a broken-line quadratic (BLQ) ascending model, all of which included heteroskedastic specifications, as dictated by the base model. The GLIMMIX procedure of SAS (version 9.4) was used to fit the base and QP models and the NLMIXED procedure was used to fit the BLL and BLQ models. We further illustrated the use of a grid search of initial parameter values to facilitate convergence and parameter estimation in nonlinear mixed models. Fit between competing dose-response models was compared using a maximum likelihood-based Bayesian information criterion (BIC). The QP, BLL, and BLQ models fitted on G:F of nursery pigs yielded BIC values of 353.7, 343.4, and 345.2, respectively, thus indicating a better fit of the BLL model. The BLL breakpoint estimate of the SID Trp:Lys ratio was 16.5% (95% confidence interval [16.1, 17.0]). Problems with

  2. Second Solid Cancers After Radiation Therapy: A Systematic Review of the Epidemiologic Studies of the Radiation Dose-Response Relationship

    Energy Technology Data Exchange (ETDEWEB)

    Berrington de Gonzalez, Amy, E-mail: berringtona@mail.nih.gov [Radiation Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, Maryland (United States); Gilbert, Ethel; Curtis, Rochelle; Inskip, Peter; Kleinerman, Ruth; Morton, Lindsay; Rajaraman, Preetha; Little, Mark P. [Radiation Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, Maryland (United States)

    2013-06-01

    Rapid innovations in radiation therapy techniques have resulted in an urgent need for risk projection models for second cancer risks from high-dose radiation exposure, because direct observation of the late effects of newer treatments will require patient follow-up for a decade or more. However, the patterns of cancer risk after fractionated high-dose radiation are much less well understood than those after lower-dose exposures (0.1-5 Gy). In particular, there is uncertainty about the shape of the dose-response curve at high doses and about the magnitude of the second cancer risk per unit dose. We reviewed the available evidence from epidemiologic studies of second solid cancers in organs that received high-dose exposure (>5 Gy) from radiation therapy where dose-response curves were estimated from individual organ-specific doses. We included 28 eligible studies with 3434 second cancer patients across 11 second solid cancers. Overall, there was little evidence that the dose-response curve was nonlinear in the direction of a downturn in risk, even at organ doses of ≥60 Gy. Thyroid cancer was the only exception, with evidence of a downturn after 20 Gy. Generally the excess relative risk per Gray, taking account of age and sex, was 5 to 10 times lower than the risk from acute exposures of <2 Gy among the Japanese atomic bomb survivors. However, the magnitude of the reduction in risk varied according to the second cancer. The results of our review provide insights into radiation carcinogenesis from fractionated high-dose exposures and are generally consistent with current theoretical models. The results can be used to refine the development of second solid cancer risk projection models for novel radiation therapy techniques.

  3. A meta-analysis including dose-response relationship between night shift work and the risk of colorectal cancer.

    Science.gov (United States)

    Wang, Xiao; Ji, Alin; Zhu, Yi; Liang, Zhen; Wu, Jian; Li, Shiqi; Meng, Shuai; Zheng, Xiangyi; Xie, Liping

    2015-09-22

    A meta-analysis was conducted to quantitatively evaluate the correlation between night shift work and the risk of colorectal cancer. We searched for publications up to March 2015 using PubMed, Web of Science, Cochrane Library, EMBASE and the Chinese National Knowledge Infrastructure databases, and the references of the retrieved articles and relevant reviews were also checked. OR and 95% CI were used to assess the degree of the correlation between night shift work and risk of colorectal cancer via fixed- or random-effect models. A dose-response meta-analysis was performed as well. The pooled OR estimates of the included studies illustrated that night shift work was correlated with an increased risk of colorectal cancer (OR = 1.318, 95% CI 1.121-1.551). No evidence of publication bias was detected. In the dose-response analysis, the rate of colorectal cancer increased by 11% for every 5 years increased in night shift work (OR = 1.11, 95% CI 1.03-1.20). In conclusion, this meta-analysis indicated that night shift work was associated with an increased risk of colorectal cancer. Further researches should be conducted to confirm our findings and clarify the potential biological mechanisms.

  4. Positioning and number of nutritional levels in dose-response trials to estimate the optimal-level and the adjustment of the models

    Directory of Open Access Journals (Sweden)

    Fernando Augusto de Souza

    2014-07-01

    Full Text Available The aim of this research was to evaluate the influence of the number and position of nutrient levels used in dose-response trials in the estimation of the optimal-level (OL and the goodness of fit on the models: quadratic polynomial (QP, exponential (EXP, linear response plateau (LRP and quadratic response plateau (QRP. It was used data from dose-response trials realized in FCAV-Unesp Jaboticabal considering the homogeneity of variances and normal distribution. The fit of the models were evaluated considered the following statistics: adjusted coefficient of determination (R²adj, coefficient of variation (CV and the sum of the squares of deviations (SSD.It was verified in QP and EXP models that small changes on the placement and distribution of the levels caused great changes in the estimation of the OL. The LRP model was deeply influenced by the absence or presence of the level between the response and stabilization phases (change in the straight to plateau. The QRP needed more levels on the response phase and the last level on stabilization phase to estimate correctly the plateau. It was concluded that the OL and the adjust of the models are dependent on the positioning and the number of the levels and the specific characteristics of each model, but levels defined near to the true requirement and not so spaced are better to estimate the OL.

  5. Dose-response relationship of dicentric chromosomes in human lymphocytes obtained for the fission neutron therapy facility MEDAPP at the research reactor FRM II.

    Science.gov (United States)

    Schmid, E; Wagner, F M; Romm, H; Walsh, L; Roos, H

    2009-02-01

    The biological effectiveness of neutrons from the neutron therapy facility MEDAPP (mean neutron energy 1.9 MeV) at the new research reactor FRM II at Garching, Germany, has been analyzed, at different depths in a polyethylene phantom. Whole blood samples were exposed to the MEDAPP beam in special irradiation chambers to total doses of 0.14-3.52 Gy at 2-cm depth, and 0.18-3.04 Gy at 6-cm depth of the phantom. The neutron and gamma-ray absorbed dose rates were measured to be 0.55 Gy min(-1) and 0.27 Gy min(-1) at 2-cm depth, while they were 0.28 and 0.25 Gy min(-1) at 6-cm depth. Although the irradiation conditions at the MEDAPP beam and the RENT beam of the former FRM I research reactor were not identical, neutrons from both facilities gave a similar linear-quadratic dose-response relationship for dicentric chromosomes at a depth of 2 cm. Different dose-response curves for dicentrics were obtained for the MEDAPP beam at 2 and 6 cm depth, suggesting a significantly lower biological effectiveness of the radiation with increasing depth. No obvious differences in the dose-response curves for dicentric chromosomes estimated under interactive or additive prediction between neutrons or gamma-rays and the experimentally obtained dose-response curves could be determined. Relative to (60)Co gamma-rays, the values for the relative biological effectiveness at the MEDAPP beam decrease from 5.9 at 0.14 Gy to 1.6 at 3.52 Gy at 2-cm depth, and from 4.1 at 0.18 Gy to 1.5 at 3.04 Gy at 6-cm depth. Using the best possible conditions of consistency, i.e., using blood samples from the same donor and the same measurement techniques for about two decades, avoiding the inter-individual variations in sensitivity or the differences in methodology usually associated with inter-laboratory comparisons, a linear-quadratic dose-response relationship for the mixed neutron and gamma-ray MEDAPP field as well as for its fission neutron part was obtained. Therefore, the debate on whether the fission

  6. Adjuvant Radiation Therapy for Margin-Positive Vulvar Squamous Cell Carcinoma: Defining the Ideal Dose-Response Using the National Cancer Data Base

    International Nuclear Information System (INIS)

    Chapman, Bhavana V.; Gill, Beant S.; Viswanathan, Akila N.; Balasubramani, Goundappa K.; Sukumvanich, Paniti; Beriwal, Sushil

    2017-01-01

    Purpose: Positive surgical margins after radical vulvectomy for vulvar cancer portend a high risk for local relapse, which may be challenging to salvage. We assessed the impact of adjuvant radiation therapy (aRT) on overall survival (OS) and the dose-response relationship using the National Cancer Data Base. Methods and Materials: Patients with vulvar squamous cell carcinoma who underwent initial extirpative surgery with positive margins from 1998 to 2012 were included. Factors associated with aRT and specific dose levels were analyzed using logistic regression. Log-rank and multivariable Cox proportional hazards modeling were used for OS analysis. Results: We identified 3075 patients with a median age of 66 years (range, 22-90 years); the median follow-up time was 36.4 months (interquartile range [IQR] 15.4-71.0 months). Stage IA/B disease represented 41.2% of the cohort. Sixty-three percent underwent lymph node assessment, with a 45% positivity rate. In total, 1035 patients (35.3%) received aRT, with a median dose of 54.0 Gy (IQR 48.6-60.0 Gy). The 3-year OS improved from 58.5% to 67.4% with aRT (P<.001). On multivariable analysis, age, Charlson-Deyo score ≥1, stage ≥II, tumors ≥4 cm, no aRT, and adverse nodal characteristics led to inferior survival. Dose of aRT was positively associated with OS as a continuous variable on univariate analysis (P<.001). The unadjusted 3-year OS for dose subsets 30.0 to 45.0 Gy, 45.1 to 53.9 Gy, 54.0 to 59.9 Gy, and ≥60 Gy was 54.3%, 55.7%, 70.1%, and 65.3%, respectively (P<.001). Multivariable analysis using a 4-month conditional landmark revealed that the greatest mortality reduction occurred in cumulative doses ≥54 Gy: 45.1 to 53.9 Gy (hazard ratio [HR] 0.94, P=.373), 54.0 to 59.9 Gy (HR 0.75, P=.024), ≥60 Gy (HR 0.71, P=.015). No survival benefit was seen with ≥60 Gy compared with 54.0 to 59.9 Gy (HR 0.95, P=.779). Conclusions: Patients with vulvar squamous cell carcinoma and positive surgical

  7. Dicentric chromosomes and γ-H2AX foci formation in lymphocytes of human blood samples exposed to a CT scanner: A direct comparison of dose response relationships

    International Nuclear Information System (INIS)

    Golfier, S.; Jost, G.; Pietsch, H.; Lengsfeld, P.; Eckardt-Schupp, F.; Schmid, E.; Voth, M.

    2009-01-01

    Experiments using the induction of dicentric chromosomes (dicentrics) as well as the γ-H2AX foci formation in lymphocytes of blood samples from a healthy donor were performed to directly evaluate the radiation sensitivity of both biological endpoints. For computed tomography scans at dose levels from 0.025 to 1 Gy, a linear-quadratic dose - response relationship for dicentrics and a linear dose - response relationship for γ-H2AX foci were obtained. The coefficients of the dose - response relationship for dicentrics are α = (3.76 ± 0.29) x 10 -2 Gy -1 and β = (5.54 ± 0.45) x 10 -2 Gy -2 , the linear coefficient for γ-H2AX foci is (7.38 ± 0.11) Gy -1 . The findings indicate that scoring of dicentrics as well as microscopic analysis of γ-H2AX foci are sensitive methods to quantify a radiation-induced biological damage at low doses. However, since γ-H2AX foci can be partially repaired within a few hours, biological damages present for days or even months, which constitute the clinically relevant endpoints, can only be quantified reliably by scoring of chromosome aberrations. Thus currently the quantification of dicentrics or reciprocal translocations remains the recommended method for estimating the effect of exposures to low dose levels of radiation ('biological dosimetry'). However, owing to the high radiation sensitivity of the γ-H2AX foci assay observed in the present study, further investigations on the effectiveness of low-linear energy transfer radiation qualities in producing γ-H2AX foci in lymphocytes from healthy donors should be performed. (authors)

  8. Dose-response relationship of induction kinetics of In vivo DNA damage and repair in mouse leukocytes exposed to gamma radiation

    International Nuclear Information System (INIS)

    Mendiola C, M.T.; Morales, R.P.

    2000-01-01

    The Unicellular electrophoresis in gel technique is a useful tool in the determination of simple ruptures and labile sites to the alkali in DNA of eucariontes cells. The determination of the induction kinetics of damage and repair of DNA can give more information. The objective of this work was to determine whether the analysis of the area under the damage/repair induction kinetics curve in comets percent or the comets frequency in the two peaks of maximum induction is adequate for determining the dose-response relationship. The mice were exposed at the doses of 0.5, 1.0, 2.0 Gy. (Author)

  9. Toxicity of TiO2 nanoparticles on soil nitrification at environmentally relevant concentrations: Lack of classical dose-response relationships.

    Science.gov (United States)

    Simonin, Marie; Martins, Jean M F; Le Roux, Xavier; Uzu, Gaëlle; Calas, Aude; Richaume, Agnès

    2017-03-01

    Titanium-dioxide nanoparticles (TiO 2 -NPs) are increasingly released in agricultural soils through, e.g. biosolids, irrigation or nanoagrochemicals. Soils are submitted to a wide range of concentrations of TiO 2 -NPs depending on the type of exposure. However, most studies have assessed the effects of unrealistically high concentrations, and the dose-response relationships are not well characterized for soil microbial communities. Here, using soil microcosms, we assessed the impact of TiO 2 -NPs at concentrations ranging from 0.05 to 500 mg kg -1  dry-soil, on the activity and abundance of ammonia-oxidizing archaea (AOA) and bacteria (AOB), and nitrite-oxidizing bacteria (Nitrobacter and Nitrospira). In addition, aggregation and oxidative potential of TiO 2 -NPs were measured in the spiking suspensions, as they can be important drivers of TiO 2 -NPs toxicity. After 90 days of exposure, non-classical dose-response relationships were observed for nitrifier abundance or activity, making threshold concentrations impossible to compute. Indeed, AOA abundance was reduced by 40% by TiO 2 -NPs whatever the concentration, while Nitrospira was never affected. Moreover, AOB and Nitrobacter abundances were decreased mainly at intermediate concentrations nitrification was reduced by 25% at the lowest (0.05 mg kg -1 ) and the highest (100 and 500 mg kg -1 ) TiO 2 -NPs concentrations. Path analyses indicated that TiO 2 -NPs affected nitrification through an effect on the specific activity of nitrifiers, in addition to indirect effects on nitrifier abundances. Altogether these results point out the need to include very low concentrations of NPs in soil toxicological studies, and the lack of relevance of classical dose-response tests and ecotoxicological dose metrics (EC50, IC50…) for TiO 2 -NPs impact on soil microorganisms.

  10. Dose-response relationship between cigarette smoking and site-specific cancer risk: protocol for a systematic review with an original design combining umbrella and traditional reviews.

    Science.gov (United States)

    Lugo, Alessandra; Bosetti, Cristina; Peveri, Giulia; Rota, Matteo; Bagnardi, Vincenzo; Gallus, Silvano

    2017-11-01

    Only a limited number of meta-analyses providing risk curve functions of dose-response relationships between various smoking-related variables and cancer-specific risk are available. To identify all relevant original publications on the issue, we will conduct a series of comprehensive systematic reviews based on three subsequent literature searches: (1) an umbrella review, to identify meta-analyses, pooled analyses and systematic reviews published before 28 April 2017 on the association between cigarette smoking and the risk of 28 (namely all) malignant neoplasms; (2) for each cancer site, an updated review of original publications on the association between cigarette smoking and cancer risk, starting from the last available comprehensive review identified through the umbrella review; and (3) a review of all original articles on the association between cigarette smoking and site-specific cancer risk included in the publications identified through the umbrella review and the updated reviews. The primary outcomes of interest will be (1) the excess incidence/mortality of various cancers for smokers compared with never smokers; and (2) the dose-response curves describing the association between smoking intensity, duration and time since stopping and incidence/mortality for various cancers. For each cancer site, we will perform a meta-analysis by pooling study-specific estimates for smoking status. We will also estimate the dose-response curves for other smoking-related variables through random-effects meta-regression models based on a non-linear dose-response relationship framework. Ethics approval is not required for this study. Main results will be published in peer-reviewed journals and will also be included in a publicly available website. We will provide therefore the most complete and updated estimates on the association between various measures of cigarette smoking and site-specific cancer risk. This will allow us to obtain precise estimates on the cancer burden

  11. Effects and Dose-Response Relationships of Motor Imagery Practice on Strength Development in Healthy Adult Populations: a Systematic Review and Meta-analysis.

    Science.gov (United States)

    Paravlic, Armin H; Slimani, Maamer; Tod, David; Marusic, Uros; Milanovic, Zoran; Pisot, Rado

    2018-05-01

    Motor imagery (MI), a mental simulation of a movement without overt muscle contraction, has been largely used to improve general motor tasks. However, the effects of MI practice on maximal voluntary strength (MVS) remain equivocal. The aims of this meta-analysis were to (1) estimate whether MI practice intervention can meaningfully improve MVS in healthy adults; (2) compare the effects of MI practice on MVS with its combination with physical practice (MI-C), and with physical practice (PP) training alone; and (3) investigate the dose-response relationships of MI practice. Seven electronic databases were searched up to April 2017. Initially 717 studies were identified; however, after evaluation of the study characteristics, data from 13 articles involving 370 participants were extracted. The meta-analysis was completed on MVS as the primary parameter. In addition, parameters associated with training volume, training intensity, and time spent training were used to investigate dose-response relationships. MI practice moderately improved MVS. When compared to conventional PP, effects were of small benefit in favour of PP. MI-C when compared to PP showed unclear effects. MI practice produced moderate effects in both upper and lower extremities on MVS. The cortical representation area of the involved muscles did not modify the effects. Meta-regression analysis revealed that (a) a training period of 4 weeks, (b) a frequency of three times per week, (c) two to three sets per single session, (d) 25 repetitions per single set, and (e) single session duration of 15 min were associated with enhanced improvements in muscle strength following MI practice. Similar dose-response relationships were observed following MI and PP. The present meta-analysis demonstrates that compared to a no-exercise control group of healthy adults, MI practice increases MVS, but less than PP. These findings suggest that MI practice could be considered as a substitute or additional training tool to

  12. Dose-response relationship between dietary magnesium intake, serum magnesium concentration and risk of hypertension: a systematic review and meta-analysis of prospective cohort studies.

    Science.gov (United States)

    Han, Hedong; Fang, Xin; Wei, Xin; Liu, Yuzhou; Jin, Zhicao; Chen, Qi; Fan, Zhongjie; Aaseth, Jan; Hiyoshi, Ayako; He, Jia; Cao, Yang

    2017-05-05

    The findings of prospective cohort studies are inconsistent regarding the association between dietary magnesium intake and serum magnesium concentration and the risk of hypertension. We aimed to review the evidence from prospective cohort studies and perform a dose-response meta-analysis to investigate the relationship between dietary magnesium intake and serum magnesium concentrations and the risk of hypertension. We searched systematically PubMed, EMBASE and the Cochrane Library databases from October 1951 through June 2016. Prospective cohort studies reporting effect estimates with 95% confidence intervals (CIs) for hypertension in more than two categories of dietary magnesium intake and/or serum magnesium concentrations were included. Random-effects models were used to combine the estimated effects. Nine articles (six on dietary magnesium intake, two on serum magnesium concentration and one on both) of ten cohort studies, including 20,119 cases of hypertension and 180,566 participates, were eligible for inclusion in the meta-analysis. We found an inverse association between dietary magnesium intake and the risk of hypertension [relative risk (RR) = 0.92; 95% CI: 0.86, 0.98] comparing the highest intake group with the lowest. A 100 mg/day increment in magnesium intake was associated with a 5% reduction in the risk of hypertension (RR = 0.95; 95% CI: 0.90, 1.00). The association of serum magnesium concentration with the risk of hypertension was marginally significant (RR = 0.91; 95% CI: 0.80, 1.02). Current evidence supports the inverse dose-response relationship between dietary magnesium intake and the risk of hypertension. However, the evidence about the relationship between serum magnesium concentration and hypertension is limited.

  13. The dose-response relationship between the patch test and ROAT and the potential use for regulatory purposes

    DEFF Research Database (Denmark)

    Fischer, Louise Arup; Voelund, Aage; Andersen, Klaus Ejner

    2009-01-01

    Background: Allergic contact dermatitis is common and can be prevented. The relationship between thresholds for patch tests and the repeated open application test (ROAT) is unclear. It would be desirable if patch test and ROAT data from already sensitized individuals could be used in prevention. ...

  14. Dose-response relationship for translocation induction in spermatogonia of the crab-eating monkey (Macaca fascicularis) by chronic γ-ray-irradiation

    International Nuclear Information System (INIS)

    Tobari, Izuo; Matsuda, Yoichi; Xiaohung, Gu; Yamagiwa, Junju; Utsugi, Toyoko; Kitazume, Masayuki; Okamoto, Masanori

    1988-01-01

    The induction of reciprocal translocations in spermatogonia of the crab-eating monkey (Macaca fascicularis) by chronic γ-irradiation was examined. The frequencies of translocation per cell were 0.15% at 0.3 Gy, 0.27% at 1.0 Gy and 0.33% at 1.5 Gy. The dose-response relationship for translocation yield was a linear one with a regression coefficient (b) of 0.16 · 10 -2 . When the slope (b) of the regression line was compared with that at a high dose rate (0.25 Gy/min, b = 1.79 · 10 -2 , it was clear that the induction rate of translocations after chronic γ-irradiation was only about one-tenth of that after high-dose-rate irradiation. Thus, there was evidence for a pronounced dose-rate effect in the crab-eating monkey. (author). 27 refs.; 2 figs.; 3 tabs

  15. Surveys of radon levels in homes in the United States: A test of the linear-no-threshold dose-response relationship for radiation carcinogenesis

    International Nuclear Information System (INIS)

    Cohen, B.L.

    1987-01-01

    The University of Pittsburgh Radon Project for large scale measurements of radon concentrations in homes is described. Its principal research is to test the linear-no threshold dose-response relationship for radiation carcinogenesis by determining average radon levels in the 25 U.S. counties (within certain population ranges) with highest and lowest lung cancer rates. The theory predicts that the former should have about 3 times higher average radon levels than the latter, under the assumption that any correlation between exposure to radon and exposure to other causes of lung cancer is weak. The validity of this assumption is tested with data on average radon level vs replies to items on questionnaires; there is little correlation between radon levels in houses and smoking habits, educational attainment, or economic status of the occupants, or with urban vs rural environs which is an indicator of exposure to air pollution

  16. Dose-response relationship of γ-ray-induced reciprocal translocations at low doses in spermatogonia of the crab-eating monkey (Macaca fascicularis)

    International Nuclear Information System (INIS)

    Matsuda, Yoichi; Tobari, Izuo; Yamagiwa, Junji; Utsugi, Toyoko; Okamoto, Masanori; Nakai, Sayaka

    1985-01-01

    The yield of translocations induced by acute γ-irradiation at low doses in the crab-eating monkey's (Macaca fascicularis) spermatogonia was examined. Over the low dose range from 0 to 1 Gy, the dose-response relationship for translocation yield was a linear one. To estimate the sensitivity to the induction of translocations in the crab-eating monkey's spermatogonia, the slope of the regression line was compared with those in other mammalian species. Consequently, over the low dose range below 1 Gy, the sensitivity of the crab-eating monkey's spermatogonia to translocation induction was similar to several mammalian species, the mouse, Chinese hamster, and the rabbit, but significantly higher than that of the rhesus monkey and lower than that of the marmoset. (Auth.)

  17. The dose-response relationship between the amount of straw provided on the floor and gastric ulceration of pars oesophagea in growing pigs

    DEFF Research Database (Denmark)

    Jensen, Karin Hjelholt; Jørgensen, Lisbeth; Haugegaard, Svend

    2017-01-01

    of straw provided affected stomach health in a curvilinear manner. Provision of up to approximately 300 g straw/pig/day progressively decreased the risk of oesophageal ulceration and scarring. At larger amounts of straw the ulceroprotective effect of straw was reduced which requires further investigation...... the structure of the stomach contents as revealed by the increased weight and dry matter content and decreased sedimentation of the digesta. Provision of approximately 300 g straw/pig/day on the floor may be a potential strategy to reduce, but not inevitably eliminate, oesophageal ulceration in pigs......The aim of the present study was (1) to determine the dose-response relationship between the amount of straw provided on the floor and oesophageal ulceration in pigs kept under typical Danish production conditions (18 pigs/pen, 0.7 m2/pig, partly slatted floor, ad libitum access to feed), (2...

  18. A dose-response relationship for marketable yield reduction of two lettuce (Lactuca sativa L.) cultivars exposed to tropospheric ozone in Southern Europe.

    Science.gov (United States)

    Marzuoli, Riccardo; Finco, Angelo; Chiesa, Maria; Gerosa, Giacomo

    2017-12-01

    The present study investigated the response to ozone (O 3 ) of two cultivars (cv.'Romana' and cv. 'Canasta') of irrigated lettuce grown in an open-top chamber (OTC) experiment in Mediterranean conditions. Two different levels of O 3 were applied, ambient O 3 in non-filtered OTCs (NF-OTCs) and -40% of ambient O 3 in charcoal-filtered OTCs (CF-OTCs), during four consecutive growing cycles. At the end of each growing cycle, the marketable yield (fresh biomass) was assessed while during the growing periods, measurements of the stomatal conductance at leaf level were performed and used to define a stomatal conductance model for calculation of the phytotoxic ozone dose (POD) absorbed by the plants.Results showed that O 3 caused statistically significant yield reductions in the first and in the last growing cycle. In general, the marketable yield of the NF-OTC plants was always lower than the CF-OTC plants for both cultivars, with mean reductions of -18.5 and -14.5% for 'Romana' and 'Canasta', respectively. On the contrary, there was no statistically significant difference in marketable yield due to the cultivar factor or to the interaction between O 3 and cultivar in any of the growing cycle performed.Dose-response relationships for the marketable relative yield based on the POD values were calculated according to different flux threshold values (Y). The best regression fit was obtained using an instantaneous flux threshold of 6 nmol O 3 m -2  s -1 (POD 6 ); the same value was obtained also for other crops. According to the generic lettuce dose-response relationship, an O 3 critical level of 1 mmol O 3 m -2 of POD 6 for a 15% of marketable yield loss was found.

  19. Transuranium element toxicity: dose-response relationships at low exposure levels. Summary and speculative interpretation relative to exposure limits

    International Nuclear Information System (INIS)

    Thompson, R.C.

    1975-01-01

    A summary is given of information on transuranium element toxicity and the correlation of this information with current established exposure limits. It is difficult to calculate a biologically relevant radiation dose from deposited plutonium; it is exposure that must be controlled in order to prevent biological effect, and if the relationship between exposure and effect is known, then radiation dose is of no concern. There are extensive data on the effects of plutonium in bone. Results of studies at the University of Utah indicate that plutonium in beagles may be as much as ten times more toxic than radium. It has been suggested that this toxicity ratio may be even higher in man than in the beagle dog because of differences in surface-to-volume ratios and differences in the rate of burial of surface-deposited plutonium. The present capabilities for extrapolating dose-effect relationships seem to be limited to the setting of upper limits, based on assumptions of linearity and considerations related to natural background

  20. Study on dose-response relationship between prenatal exposure to tritiated water and the developmental retardation of brain in rats

    International Nuclear Information System (INIS)

    Yang Zhiyuan; Guo Yuefeng; Wang Mingming

    1993-01-01

    The developmental retardation of brain in rats induced by parenatal exposure to HTO had observed by measuring the contents of cerebral amino acids. The HTO was injected intraperitoneally at the 11 th day of gestation with concentration of 7.4 x 10 3 -3.7 x 10 6 Bq/ml (body water). At 18-day-old the young rats were killed and their brains were separated from skulls. The brains were used to make biochemical specimens for measuring the contents of amino acids. The results showed that the contents of amino acids increases with the dose increased and the relationship between the percentage of the increased contents of amino acids in brain and logarithm of absorbed doses (D, Gy) give a good fit to liner regression equation in range of the absorbed doses from 0.0038-1.9 Gy

  1. Rethinking the dose-response relationship between usage and outcome in an online intervention for depression: randomized controlled trial.

    Science.gov (United States)

    Donkin, Liesje; Hickie, Ian B; Christensen, Helen; Naismith, Sharon L; Neal, Bruce; Cockayne, Nicole L; Glozier, Nick

    2013-10-17

    There is now substantial evidence that Web-based interventions can be effective at changing behavior and successfully treating psychological disorders. However, interest in the impact of usage on intervention outcomes has only been developed recently. To date, persistence with or completion of the intervention has been the most commonly reported metric of use, but this does not adequately describe user behavior online. Analysis of alternative measures of usage and their relationship to outcome may help to understand how much of the intervention users may need to obtain a clinically significant benefit from the program. The objective of this study was to determine which usage metrics, if any, are associated with outcome in an online depression treatment trial. Cardiovascular Risk E-couch Depression Outcome (CREDO) is a randomized controlled trial evaluating an unguided Web-based program (E-couch) based on cognitive behavioral therapy and interpersonal therapy for people with depression and cardiovascular disease. In all, 280 participants in the active arm of the trial commenced the program, delivered in 12 modules containing pages of text and activities. Usage data (eg, number of log-ins, modules completed, time spent online, and activities completed) were captured automatically by the program interface. We estimated the association of these and composite metrics with the outcome of a clinically significant improvement in depression score on the Patient Health Questionnaire (PHQ-9) of ≥ 5 points. In all, 214/280 (76.4%) participants provided outcome data at the end of the 12-week period and were included in the analysis. Of these, 94 (43.9%) participants obtained clinically significant improvement. Participants logged into the program an average of 18.7 times (SD 8.3) with most (62.1%, 133/214) completing all 12 modules. Average time spent online per log-in was 17.3 minutes (SD 10.5). Participants completed an average of 9 of 18 activities available within the

  2. Influence of dose and its distribution in time on dose-response relationships for low-LET radiation

    International Nuclear Information System (INIS)

    Anon.

    1980-01-01

    This book examines the influence of dose rate and magnitude on the genetic and carcinogenic effects of radiation exposure in animals and man. It systematically examines a broad range of biological effects in simple systems, plants, laboratory animals, and man with special attention given to the effects of prenatal irradiation, changes in life span, and tumorigenesis. An enormous volume of data is provided about human tumorigenesis and the data and shortcomings are summarized. There is an extended general discussion of the consideration in quantitative dose and dose rate relationships and of the limitations of the data and analyses which have led to a linear interpolation of risk at low doses and dose rates. An argument is made for dose rate dependence in tumorigenesis as being consistent with all other radiation effects and for the applicability of Dose Rate Effectiveness Factors (DREF) in providing a more realistic assessment of the risk of radiation carcinogenesis. The report is documented with 24 pages of references. There are numerous graphs and tables, all clear and to the point. This book is a superb review and summary of the data on radiation risks

  3. Nonlinearity and thresholds in dose-response relationships for carcinogenicity due to sampling variation, logarithmic dose scaling, or small differences in individual susceptibility

    International Nuclear Information System (INIS)

    Lutz, W.K.; Gaylor, D.W.; Conolly, R.B.; Lutz, R.W.

    2005-01-01

    Nonlinear and threshold-like shapes of dose-response curves are often observed in tests for carcinogenicity. Here, we present three examples where an apparent threshold is spurious and can be misleading for low dose extrapolation and human cancer risk assessment. Case 1: For experiments that are not replicated, such as rodent bioassays for carcinogenicity, random variation can lead to misinterpretation of the result. This situation was simulated by 20 random binomial samplings of 50 animals per group, assuming a true linear dose response from 5% to 25% tumor incidence at arbitrary dose levels 0, 0.5, 1, 2, and 4. Linearity was suggested only by 8 of the 20 simulations. Four simulations did not reveal the carcinogenicity at all. Three exhibited thresholds, two showed a nonmonotonic behavior with a decrease at low dose, followed by a significant increase at high dose ('hormesis'). Case 2: Logarithmic representation of the dose axis transforms a straight line into a sublinear (up-bent) curve, which can be misinterpreted to indicate a threshold. This is most pronounced if the dose scale includes a wide low dose range. Linear regression of net tumor incidences and intersection with the dose axis results in an apparent threshold, even with an underlying true linear dose-incidence relationship. Case 3: Nonlinear shapes of dose-cancer incidence curves are rarely seen with epidemiological data in humans. The discrepancy to data in rodents may in part be explained by a wider span of individual susceptibilities for tumor induction in humans due to more diverse genetic background and modulation by co-carcinogenic lifestyle factors. Linear extrapolation of a human cancer risk could therefore be appropriate even if animal bioassays show nonlinearity

  4. Fluctuating asymmetry in Bobwhite quail chicks (Colinus virginianus) does not follow a predictable dose-response relationship following maternal exposure to four different herbicides

    International Nuclear Information System (INIS)

    Knopper, Loren D.; Mineau, Pierre

    2004-01-01

    Most biomonitoring studies that have investigated the relationship between fluctuating asymmetry (FA) and anthropogenic stressors have measured organisms from polluted ecosystems and compared them to organisms at reference sites. What has received little attention is whether FA follows a dose-response relationship with stress, a key criterion of a useful biomarker. Using chicks from currently mandated avian reproductive tests we tested whether a composite index of FA (FA C ), was related to the dose or duration of exposure of their parents to one of four different herbicides, and if FA C was indeed a more sensitive marker of stress than standard reproductive endpoints measured from this test. We found no consistent relationship between FA C and dose or duration of herbicide exposure in any of the four studies. Exposure to one of the four pesticides did result in significant reproductive toxicity but this was not accompanied or foreshadowed by higher levels of FA C . Our results do not support the hypothesis that FA is a reliable general biomarker of pesticide exposure

  5. Health effects of low doses at low dose rates: dose-response relationship modeling in a cohort of workers of the nuclear industry

    International Nuclear Information System (INIS)

    Metz-Flamant, Camille

    2011-01-01

    The aim of this thesis is to contribute to a better understanding of the health effects of chronic external low doses of ionising radiation. This work is based on the French cohort of CEA-AREVA NC nuclear workers. The mains stages of this thesis were (1) conducting a review of epidemiological studies on nuclear workers, (2) completing the database and performing a descriptive analysis of the cohort, (3) quantifying risk by different statistical methods and (4) modelling the exposure-time-risk relationship. The cohort includes monitored workers employed more than one year between 1950 and 1994 at CEA or AREVA NC companies. Individual annual external exposure, history of work, vital status and causes of death were reconstructed for each worker. Standardized mortality ratios using French national mortality rates as external reference were computed. Exposure-risk analysis was conducted in the cohort using the linear excess relative risk model, based on both Poisson regression and Cox model. Time dependent modifying factors were investigated by adding an interaction term in the model or by using exposure time windows. The cohort includes 36, 769 workers, followed-up until age 60 in average. During the 1968- 2004 period, 5, 443 deaths, 2, 213 cancers, 62 leukemia and 1, 314 cardiovascular diseases were recorded. Among the 57% exposed workers, the mean cumulative dose was 21.5 milli-sieverts (mSv). A strong Healthy Worker Effect is observed in the cohort. Significant elevated risks of pleura cancer and melanoma deaths were observed in the cohort but not associated with dose. No significant association was observed with solid cancers, lung cancer and cardiovascular diseases. A significant dose-response relationship was observed for leukemia excluding chronic lymphatic leukemia, mainly for doses received less than 15 years before and for yearly dose rates higher than 10 mSv. This PhD work contributes to the evaluation of risks associated to chronic external radiation

  6. Effectiveness of home- and community-based rehabilitation in a large cohort of patients disabled by cerebrovascular accident: evidence of a dose-response relationship.

    Science.gov (United States)

    Altman, Irwin M; Swick, Shannon; Malec, James F

    2013-09-01

    To (1) assess the effectiveness of home- and community-based rehabilitation (HCBR) in a large cohort of individuals with disabilities secondary to cerebrovascular accident (CVA); and (2) evaluate the responsiveness to treatment of the Mayo-Portland Adaptability Inventory (MPAI-4) to changes resulting from HCBR in this patient group. Retrospective analysis of program evaluation data for treatment completers and noncompleters. HCBR conducted in 7 geographically distinct U.S. cities. Individuals with CVA (n=738) who completed the prescribed course of rehabilitation (completed course of treatment [CCT]) compared with 150 individuals who were precipitously discharged (PD) before program completion. HCBR delivered by certified professional staff on an individualized basis. Mayo-Portland Adaptability Inventory (MPAI-4) completed by professional consensus on admission and at discharge. With the use of analysis of covariance, MPAI-4 total scores at discharge for CCT participants were compared with those of PD participants, with admission MPAI-4, age, length of stay, and time since event as covariates. CCT participants showed greater improvement than PD participants (F=99.48, PMPAI-4 indexes than those in the PD group who were discharged before completing the prescribed program. This dose-response relationship provides evidence of a causal relationship between treatment and outcome. Copyright © 2013 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

  7. Comparison of Community Response to Road Traffic Noise in Japan and SWEDEN—PART i: Outline of Surveys and DOSE-RESPONSE Relationships

    Science.gov (United States)

    SATO, T.; YANO, T.; BJÖRKMAN, M.; RYLANDER, R.

    2002-02-01

    To investigate cross-cultural differences in the community response to road traffic noise, social surveys were conducted in Gothenburg, Sweden, and Kumamoto and Sapporo, Japan, using the same questionnaire and noise measurement method. Typical residential areas with detached houses and apartments were selected as the target areas in each city. The questionnaire comprised 40 questions relating to environmental, housing and personal factors. The key questions concerned annoyance caused by road traffic noise. The total numbers of respondents were 1142 in Gothenburg, 837 in Kumamoto and 780 in Sapporo. The response rates were 68·8, 69·3 and 57·5% respectively. After the questionnaires were completed, noise measurements were made in each area. Community responses were compared on the basis of the dose-response relationships. There were no systematic differences between community responses in Sapporo and Kumamoto, which have the same culture. People living in detached houses in Gothenburg were more annoyed by the same road traffic noise than the people living in Japanese cities. There were no systematic differences among the three cities with regard to activity disturbances indoors, but significant disturbance of activities and resting in gardens or on balconies was noted in Gothenburg. The difference in activity disturbance was due to the differences between lifestyles in the two countries. People living in detached houses were more annoyed by the house vibration caused by road traffic than those living in apartments and people were annoyed by the exhaust from road traffic to the same extent as noise.

  8. Quantifying the dose-response relationship between circulating folate concentrations and colorectal cancer in cohort studies: a meta-analysis based on a flexible meta-regression model.

    Science.gov (United States)

    Chuang, Shu-Chun; Rota, Matteo; Gunter, Marc J; Zeleniuch-Jacquotte, Anne; Eussen, Simone J P M; Vollset, Stein Emil; Ueland, Per Magne; Norat, Teresa; Ziegler, Regina G; Vineis, Paolo

    2013-10-01

    Most epidemiologic studies on folate intake suggest that folate may be protective against colorectal cancer, but the results on circulating (plasma or serum) folate are mostly inconclusive. We conducted a meta-analysis of case-control studies nested within prospective studies on circulating folate and colorectal cancer risk by using flexible meta-regression models to test the linear and nonlinear dose-response relationships. A total of 8 publications (10 cohorts, representing 3,477 cases and 7,039 controls) were included in the meta-analysis. The linear and nonlinear models corresponded to relative risks of 0.96 (95% confidence interval (CI): 0.91, 1.02) and 0.99 (95% CI: 0.96, 1.02), respectively, per 10 nmol/L of circulating folate in contrast to the reference value. The pooled relative risks when comparing the highest with the lowest category were 0.80 (95% CI: 0.61, 0.99) for radioimmunoassay and 1.03 (95% CI: 0.83, 1.22) for microbiological assay. Overall, our analyses suggest a null association between circulating folate and colorectal cancer risk. The stronger association for the radioimmunoassay-based studies could reflect differences in cohorts and study designs rather than assay performance. Further investigations need to integrate more accurate measurements and flexible modeling to explore the effects of folate in the presence of genetic, lifestyle, dietary, and hormone-related factors.

  9. Analysis of the dose-response relationships of chromosomal aberrations after irradiation and bleomycin exposure of different human lymphocyte fractions in vitro

    International Nuclear Information System (INIS)

    Dresp, J.

    1979-01-01

    Cytogenetic analyses could be carried out on whole blood and pure T-cell cultures and also on cells of the 'buffy-coat'. In pure B-cell cultures even after 96 hours no mitogenic stimulation could be achieved. Parameters of radiosensitivity and bleomycin sensitivity were dicentric chromosomes, for which the dose-response relationships were calculated. Chromosomal investigations on the 'buffy-coat' cells did not provide indications referring to a varying radiosensitivity compared to whole blood cultures. In pure T-cell cultures T-lymphocytes, which had been separated after whole blood irradiation exposure, showed lower aberration rates than lymphocytes, which had been cultured after whole blood irradiation without previous separation. In the case of bleomycin exposure the treatment of previously separated leucocytes and T-lymphocytes respectively, led to lower aberration rates than the treatment before separation. Therefore it is apparently not necessary for a cytogenetic dosimetry or mutagenicity to depart from the whole blood culture method. (orig./MG) [de

  10. Systematic review and meta-analysis of reduction in all-cause mortality from walking and cycling and shape of dose response relationship.

    Science.gov (United States)

    Kelly, Paul; Kahlmeier, Sonja; Götschi, Thomas; Orsini, Nicola; Richards, Justin; Roberts, Nia; Scarborough, Peter; Foster, Charlie

    2014-10-24

    Walking and cycling have shown beneficial effects on population risk of all-cause mortality (ACM). This paper aims to review the evidence and quantify these effects, adjusted for other physical activity (PA). We conducted a systematic review to identify relevant studies. Searches were conducted in November 2013 using the following health databases of publications: Embase (OvidSP); Medline (OvidSP); Web of Knowledge; CINAHL; SCOPUS; SPORTDiscus. We also searched reference lists of relevant texts and reviews. Eligible studies were prospective cohort design and reporting walking or cycling exposure and mortality as an outcome. Only cohorts of individuals healthy at baseline were considered eligible. Extracted data included study population and location, sample size, population characteristics (age and sex), follow-up in years, walking or cycling exposure, mortality outcome, and adjustment for other co-variables. We used random-effects meta-analyses to investigate the beneficial effects of regular walking and cycling. Walking (18 results from 14 studies) and cycling (8 results from 7 studies) were shown to reduce the risk of all-cause mortality, adjusted for other PA. For a standardised dose of 11.25 MET.hours per week (or 675 MET.minutes per week), the reduction in risk for ACM was 11% (95% CI = 4 to 17%) for walking and 10% (95% CI = 6 to 13%) for cycling. The estimates for walking are based on 280,000 participants and 2.6 million person-years and for cycling they are based on 187,000 individuals and 2.1 million person-years. The shape of the dose-response relationship was modelled through meta-analysis of pooled relative risks within three exposure intervals. The dose-response analysis showed that walking or cycling had the greatest effect on risk for ACM in the first (lowest) exposure interval. The analysis shows that walking and cycling have population-level health benefits even after adjustment for other PA. Public health approaches would have the biggest impact

  11. In search of a dose-response relationship with radiotherapy in the management of recurrent rectal carcinoma in the pelvis: a systematic review

    International Nuclear Information System (INIS)

    Wong, Rebecca; Thomas, Gillian; Cummings, Bernard; Froud, Peter; Shelley, Wendy; Withers, Rodney; Williams, Jack

    1998-01-01

    Purpose: A systematic review of the literature was undertaken to address the question: ''What is the most effective dose fractionation schedule for the relief of symptoms in patients with pelvic recurrence from rectal or colorectal carcinoma?'' Methods and Materials: Cancerlit/Medline-computerized databases were searched between the years 1966-1996. Studies that explored the response to radiotherapy in patients with pelvic recurrence from rectal/rectosigmoid carcinoma were included. Factors that may contribute to differences in results were postulated in advance and the variations encountered between articles were presented. Articles with data applicable to recurrent disease only were included in the primary analysis. The effect of including articles that reported outcomes of recurrences with unresectable primaries and residual disease was presented as a sensitivity analysis. Results: Only retrospective series (level V evidence) were available. The many sources of potential bias inherent in retrospective analyses make the data suitable for hypothesis generation only. Comparison of response was made between 'lower' vs. 'higher' doses, using 45-50 Gy as the dividing dose, base on the primary analysis. There were no significant differences observable in terms of initial response and the proportion maintaining a response at 6 months, within the range of doses employed. When data from articles that reported outcomes of recurrent disease with primary untreated cancers and postoperative residual disease were included, there was a suggestion for a more favorable response with higher doses. This requires cautious interpretation within the methodological limitations of the data. Conclusion: The optimal dose fractionation schedule for the palliation of pelvic recurrence from rectal carcinoma remains undefined. Well-designed randomized studies, with study arms that are sufficiently diverse biologically to allow the detection of a dose-response relationship if one existed

  12. Dose-response relationships between occupational exposure to potash, diesel exhaust and nitrogen oxides and lung function: cross-sectional and longitudinal study in two salt mines.

    Science.gov (United States)

    Lotz, Gabriele; Plitzko, Sabine; Gierke, Erhardt; Tittelbach, Ulrike; Kersten, Norbert; Schneider, W Dietmar

    2008-08-01

    Several studies have shown that underground salt miners may have an increased incidence of chest symptoms and sometimes decreased lung function. Miners of two salt mines were investigated to evaluate relationships between the lung function and the workplace exposure. The effect of nitrogen monoxide (NO) and nitrogen dioxide (NO(2)) was investigated in view of the recent debate on European occupational exposure limits. A total of 410/463 miners (mine A/mine B) were examined cross-sectional and 75/64% of the first cohort were examined after a 5-year period. Exposure was measured by personal sampling. Personal lifetime exposure doses of salt dust, diesel exhaust, NO(2) and NO were calculated for all miners. Dose-response relationships were calculated by multiple regression analysis. Each exposure component acted as an indicator for the complex exposure. Exposure response relationships were shown in the cross-sectional and longitudinal investigations in both mines. In the 5-year period, the adjusted (age, smoking, etc.) effect of the exposure indicators resulted in a mean decrease of FEV(1) between -18 ml/year (mine A) and -10 ml/year (mine B). The personal concentrations related to this effect were 12.6/7.1 mg/m(3) inhalable dust, 2.4/0.8 mg/m(3) respirable dust, 0.09/0.09 mg/m(3) diesel exhaust, 0.4/0.5 ppm NO(2) and 1.7/1.4 ppm NO (mine A/B). Exposure was related to symptoms of chronic bronchitis only in mine B. The effects found in both mines indicate that the mixed exposure can cause lung function disorders in salt miners exposed over a long time. Because of the high correlation of the concentrations it was not possible to determine the effects of a single exposure component separately or to recommend a specific occupational exposure limit. However, possible maximum effects associated with the mixed exposure can be evaluated in the ranges of concentrations of the individual substances in the mines.

  13. The importance of body weight for the dose response relationship of oral vitamin D supplementation and serum 25-hydroxyvitamin D in healthy volunteers.

    Science.gov (United States)

    Ekwaru, John Paul; Zwicker, Jennifer D; Holick, Michael F; Giovannucci, Edward; Veugelers, Paul J

    2014-01-01

    Unlike vitamin D recommendations by the Institute of Medicine, the Clinical Practice Guidelines by the Endocrine Society acknowledge body weight differentials and recommend obese subjects be given two to three times more vitamin D to satisfy their body's vitamin D requirement. However, the Endocrine Society also acknowledges that there are no good studies that clearly justify this. In this study we examined the combined effect of vitamin D supplementation and body weight on serum 25-hydroxyvitamin (25(OH)D) and serum calcium in healthy volunteers. We analyzed 22,214 recordings of vitamin D supplement use and serum 25(OH)D from 17,614 healthy adult volunteers participating in a preventive health program. This program encourages the use of vitamin D supplementation and monitors its use and serum 25(OH)D and serum calcium levels. Participants reported vitamin D supplementation ranging from 0 to 55,000 IU per day and had serum 25(OH)D levels ranging from 10.1 to 394 nmol/L. The dose response relationship between vitamin D supplementation and serum 25(OH)D followed an exponential curve. On average, serum 25(OH)D increased by 12.0 nmol/L per 1,000 IU in the supplementation interval of 0 to 1,000 IU per day and by 1.1 nmol/L per 1,000 IU in the supplementation interval of 15,000 to 20,000 IU per day. BMI, relative to absolute body weight, was found to be the better determinant of 25(OH)D. Relative to normal weight subjects, obese and overweight participants had serum 25(OH)D that were on average 19.8 nmol/L and 8.0 nmol/L lower, respectively (Pvitamin D supplementation. We recommend vitamin D supplementation be 2 to 3 times higher for obese subjects and 1.5 times higher for overweight subjects relative to normal weight subjects. This observational study provides body weight specific recommendations to achieve 25(OH)D targets.

  14. The importance of body weight for the dose response relationship of oral vitamin D supplementation and serum 25-hydroxyvitamin D in healthy volunteers.

    Directory of Open Access Journals (Sweden)

    John Paul Ekwaru

    Full Text Available Unlike vitamin D recommendations by the Institute of Medicine, the Clinical Practice Guidelines by the Endocrine Society acknowledge body weight differentials and recommend obese subjects be given two to three times more vitamin D to satisfy their body's vitamin D requirement. However, the Endocrine Society also acknowledges that there are no good studies that clearly justify this. In this study we examined the combined effect of vitamin D supplementation and body weight on serum 25-hydroxyvitamin (25(OHD and serum calcium in healthy volunteers. We analyzed 22,214 recordings of vitamin D supplement use and serum 25(OHD from 17,614 healthy adult volunteers participating in a preventive health program. This program encourages the use of vitamin D supplementation and monitors its use and serum 25(OHD and serum calcium levels. Participants reported vitamin D supplementation ranging from 0 to 55,000 IU per day and had serum 25(OHD levels ranging from 10.1 to 394 nmol/L. The dose response relationship between vitamin D supplementation and serum 25(OHD followed an exponential curve. On average, serum 25(OHD increased by 12.0 nmol/L per 1,000 IU in the supplementation interval of 0 to 1,000 IU per day and by 1.1 nmol/L per 1,000 IU in the supplementation interval of 15,000 to 20,000 IU per day. BMI, relative to absolute body weight, was found to be the better determinant of 25(OHD. Relative to normal weight subjects, obese and overweight participants had serum 25(OHD that were on average 19.8 nmol/L and 8.0 nmol/L lower, respectively (P<0.001. We did not observe any increase in the risk for hypercalcemia with increasing vitamin D supplementation. We recommend vitamin D supplementation be 2 to 3 times higher for obese subjects and 1.5 times higher for overweight subjects relative to normal weight subjects. This observational study provides body weight specific recommendations to achieve 25(OHD targets.

  15. Dose-response relationship of nasopharyngeal carcinoma above conventional tumoricidal level: A study by the Hong Kong nasopharyngeal carcinoma study group (HKNPCSG)

    International Nuclear Information System (INIS)

    Teo, Peter M.L.; Leung, S.F.; Tung, Stewart Y.; Zee, Benny; Sham, Jonathan S.T.; Lee, Anne W.M.; Lau, W.H.; Kwan, W.H.; Leung, T.W.; Chua, Daniel; Sze, Wai Man; Au, Joseph S.K.; Yu, K.H.; O, Sai Ki; Kwong, Dora; Yau, T.K.; Law, Stephen C.K.; Sze, Wing Kin; Au, Gordon; Chan, Anthony T.C.

    2006-01-01

    Background and purpose: To define the dose-response relationship of nasopharyngeal carcinoma (NPC) above the conventional tumoricidal dose level of 66 Gy when the basic radiotherapy (RT) course was given by the 2D Ho's technique. Patients and methods: Data from all five regional cancer centers in Hong Kong were pooled for this retrospective study. All patients (n=2426) were treated with curative-intent RT with or without chemotherapy between 1996 and 2000 with the basic RT course using the Ho's technique. The primary endpoint was local control. The prognostic significance of dose-escalation ('boost') after 66 Gy, T-stage, N-stage, use of chemotherapy, sex and age (≤40 years vs >40 years) was studied. Both univariate and multivariate analyses were performed. Results: On multivariate analysis, T-stage (P< 0.01; hazard ratio [HR], 1.58) and optimal boost (P=0.01; HR, 0.34) were the only significant factors affecting local failure for the whole study population, and for the population of patients treated by radiotherapy alone, but not for patients who also received chemotherapy. The following were independent determinants of local failure for patient groups with different T-stages treated by radiotherapy alone: use of a boost in T1/T2a disease (P=0.01; HR, 0.33); use of a boost (P<0.01; HR, 0.60) and age (P=0.01; HR, 1.02) in T3/T4 tumors. Among patients with T2b tumors treated by radiotherapy alone and given a boost, the use of a 20 Gy-boost gave a lower local failure rate than a 10 Gy-boost. There was no apparent excess mortality attributed to RT complications. Conclusions: Within the context of a multi-center retrospective study, dose-escalation above 66 Gy significantly improved local control for T1/T2a and T3/4 tumors when the primary RT course was based on the 2D Ho's technique without additional chemotherapy. 'Boosting' in NPC warrants further investigation. Caution should be taken when boosting is considered because of possible increase in radiation toxicity

  16. Experimental data and dose-response models

    International Nuclear Information System (INIS)

    Ullrich, R.L.

    1985-01-01

    Dose-response relationships for radiation carcinogenesis have been of interest to biologists, modelers, and statisticians for many years. Despite his interest there are few instances in which there are sufficient experimental data to allow the fitting of various dose-response models. In those experimental systems for which data are available the dose-response curves for tumor induction for the various systems cannot be described by a single model. Dose-response models which have been observed following acute exposures to gamma rays include threshold, quadratic, and linear models. Data on sex, age, and environmental influences of dose suggest a strong role of host factors on the dose response. With decreasing dose rate the effectiveness of gamma ray irradiation tends to decrease in essentially every instance. In those cases in which the high dose rate dose response could be described by a quadratic model, the effect of dose rate is consistent with predictions based on radiation effects on the induction of initial events. Whether the underlying reasons for the observed dose-rate effect is a result of effects on the induction of initial events or is due to effects on the subsequent steps in the carcinogenic process is unknown. Information on the dose response for tumor induction for high LET (linear energy transfer) radiations such as neutrons is even more limited. The observed dose and dose rate data for tumor induction following neutron exposure are complex and do not appear to be consistent with predictions based on models for the induction of initial events

  17. Comparative studies of the dose-response relationship of radiation-induced chromosomal aberrations in human lymphocytes induced by low radiation doses, using Feulgen orcein glacial acetic acid and FPG staining

    International Nuclear Information System (INIS)

    Wagner, R.

    1982-01-01

    Peripheral lymphocytes were exposed in vitro to 220 kV X-radiation, with doses of 0.05, 0.1, 0.2, 0.4, and 0.5 Gy, their culture and preparation was made under standardized conditions. The slides were stained using two different methods, namely FPG staining (fluorescence plus giemsa), and the conventional Feulgen orcein glacial acetic acid method. Compared to the conventional method, FPG staining achieved absolute yields of acentric fragments three times higher, and of dicentric chromosomes twice as high. A linear dose-response relationship in acentric fragments was found by the two staining methods alike, which agrees with the theory. Both staining methods revealed a linear-square dose-response relationship in dicentric chromosomes. Using FPG staining, preparing only M 1 cells for evaluation, the linear component was found to be dominant over the whole dose range applied. The conventional method, analysing M 1 and M 2 cells, revealed the square component to be the most important one. The dose-response relationships determined after FPG staining can be used for biological dosimetry. Calibration can be improved by increasing the number of cells analysed at doses [de

  18. Dose-response relationship in locoregional control for patients with stage II-III esophageal cancer treated with concurrent chemotherapy and radiotherapy

    International Nuclear Information System (INIS)

    Zhang Zhen; Liao Zhongxing; Jin Jing; Ajani, Jaffer; Chang, Joe Y.; Jeter, Melenda; Guerrero, Thomas; Stevens, Craig W.; Swisher, Stephen; Ho, Linus; Yao, James; Allen, Pamela; Cox, James D.; Komaki, Ritsuko

    2005-01-01

    it was difficult to assess the side effects accurately in a retrospective fashion. On multivariate analysis, Stage II (vs. III) disease and radiation dose >51 Gy were independent predictors of improved LRC, and locoregional failure was an independent predictor of worse overall survival. Conclusion: Our data suggested a positive correlation between radiation dose and LRC in the population studied. A higher radiation dose was associated with increased LRC and survival in the dose range studied. The data also suggested that better LRC was associated with a lower rate of distant metastasis. A threshold of tumor response to radiation dose might be present, as suggested by the flattened slope in the high-dose area on the dose-response curve. A carefully designed dose-escalation study is required to confirm this assumption

  19. Single toxin dose-response models revisited

    Energy Technology Data Exchange (ETDEWEB)

    Demidenko, Eugene, E-mail: eugened@dartmouth.edu [Department of Biomedical Data Science, Geisel School of Medicine at Dartmouth, Hanover, NH03756 (United States); Glaholt, SP, E-mail: sglaholt@indiana.edu [Indiana University, School of Public & Environmental Affairs, Bloomington, IN47405 (United States); Department of Biological Sciences, Dartmouth College, Hanover, NH03755 (United States); Kyker-Snowman, E, E-mail: ek2002@wildcats.unh.edu [Department of Natural Resources and the Environment, University of New Hampshire, Durham, NH03824 (United States); Shaw, JR, E-mail: joeshaw@indiana.edu [Indiana University, School of Public & Environmental Affairs, Bloomington, IN47405 (United States); Chen, CY, E-mail: Celia.Y.Chen@dartmouth.edu [Department of Biological Sciences, Dartmouth College, Hanover, NH03755 (United States)

    2017-01-01

    The goal of this paper is to offer a rigorous analysis of the sigmoid shape single toxin dose-response relationship. The toxin efficacy function is introduced and four special points, including maximum toxin efficacy and inflection points, on the dose-response curve are defined. The special points define three phases of the toxin effect on mortality: (1) toxin concentrations smaller than the first inflection point or (2) larger then the second inflection point imply low mortality rate, and (3) concentrations between the first and the second inflection points imply high mortality rate. Probabilistic interpretation and mathematical analysis for each of the four models, Hill, logit, probit, and Weibull is provided. Two general model extensions are introduced: (1) the multi-target hit model that accounts for the existence of several vital receptors affected by the toxin, and (2) model with a nonzero mortality at zero concentration to account for natural mortality. Special attention is given to statistical estimation in the framework of the generalized linear model with the binomial dependent variable as the mortality count in each experiment, contrary to the widespread nonlinear regression treating the mortality rate as continuous variable. The models are illustrated using standard EPA Daphnia acute (48 h) toxicity tests with mortality as a function of NiCl or CuSO{sub 4} toxin. - Highlights: • The paper offers a rigorous study of a sigmoid dose-response relationship. • The concentration with highest mortality rate is rigorously defined. • A table with four special points for five morality curves is presented. • Two new sigmoid dose-response models have been introduced. • The generalized linear model is advocated for estimation of sigmoid dose-response relationship.

  20. The induction by x rays of chromosome aberrations in male guinea-pigs, rabbits and golden hamsters. 3. Dose-response relationship after single doses of X-rays to spermatogonia

    Energy Technology Data Exchange (ETDEWEB)

    Lyon, M F; Cox, B D

    1975-09-01

    The induction by X-rays of translocations in spermatogonia was studied by cytological means in spermatocytes derived from them. In the rabbit and guinea-pig, hump-shaped dose-response curves were obtained, with a linear relationship at the low doses. The shapes of the curves were similar to those reported for the mouse, except that the maximum occurred at 600-700 rad in the mouse as opposed to 300 rad in the guinea-pig and rabbit. Unlike the guinea-pig and rabbit, the golden hamster showed a hump dose-response curve without a definite peak value and with little decrease in yield at high radiation doses. Over the low dose range 100-300 rad, the slopes of the curves of translocation yield were in the order: mouse (highest), rabbit, guinea-pig and hamster. Data on sterile periods suggested that the amount of spermatogonial killing in the rabbit and guinea-pig was as great or greater than in the mouse, and that in the golden hamster it was most severe. It is suggested that the differing shapes of the dose-response curves can be explained by a lower sensitivity to translocation induction in the test species and, also especially in the golden hamster, a greater sensitivity to cell killing. The possibility of extrapolating from these data to other species is discussed.

  1. Dose-response relationship of neutrons and γ rays to leukemia incidence among atomic bomb survivors in Hiroshima and Nagasaki by type of leukemia, 1950--1971

    International Nuclear Information System (INIS)

    Ishimaru, T.; Otake, M.; Ichimaru, M.

    1979-01-01

    The incidence of leukemia during 1950 to 1971 in a fixed mortality sample of atomic bomb survivors in Hiroshima and Nagasaki was analyzed as a function of neutron and γ kerma and marrow doses. Two dose-response models were tested for acute leukemia, chronic granulocytic leukemia, and all types of leukemia, respectively. Each model postulates that the leukemia incidence depends upon the sum of separate risks imposed by γ and neutron doses. In Model I the risk from both types of radiation is assumed to be directly proportional to the respective doses, while Model II assumes that whereas the risk from neutrons is directly proportional to the dose, the risk from γ rays is proportional to dose-squared. The analysis demonstrated that the dose-response of the two types of leukemia differed by type of radiation. The data suggested that the response of acute leukemia was best explained by Model II, while the response of chronic granulocytic leukemia depended almost linearly upon neutron dose alone, because the regression coefficients associated with γ radiation for both Models I and II were not significant. The relative biological effectiveness (RBE) of neutrons in relation to γ rays for incidence of acute leukemia was estimated to be approximately 30/(Dn)/sup 1/2/ [95% confidence limits; 17/(Dn)/sup 1/2/ approx. 54/(Dn)/sup 1/2/] for kerma and 32/(Dn)/sup 1/2/ [95% confidence limits; 18/(Dn)/sup 1/2/ approx. 58/(Dn)/sup 1/2/] for marrow dose (Dn = neutron dose). If acute and chronic granulocytic leukemias are considered together as all types of leukemia, Model II appears to fit the data slightly better than Model I, but neither model is statistically rejected by the data

  2. Dose-response-a challenge for allelopathy?

    Science.gov (United States)

    Belz, Regina G; Hurle, Karl; Duke, Stephen O

    2005-04-01

    The response of an organism to a chemical depends, among other things, on the dose. Nonlinear dose-response relationships occur across a broad range of research fields, and are a well established tool to describe the basic mechanisms of phytotoxicity. The responses of plants to allelochemicals as biosynthesized phytotoxins, relate as well to nonlinearity and, thus, allelopathic effects can be adequately quantified by nonlinear mathematical modeling. The current paper applies the concept of nonlinearity to assorted aspects of allelopathy within several bioassays and reveals their analysis by nonlinear regression models. Procedures for a valid comparison of effective doses between different allelopathic interactions are presented for both, inhibitory and stimulatory effects. The dose-response applications measure and compare the responses produced by pure allelochemicals [scopoletin (7-hydroxy-6-methoxy-2H-1-benzopyran-2-one); DIBOA (2,4-dihydroxy-2H-1,4-benzoxaxin-3(4H)-one); BOA (benzoxazolin-2(3H)-one); MBOA (6-methoxy-benzoxazolin-2(3H)-one)], involved in allelopathy of grain crops, to demonstrate how some general principles of dose responses also relate to allelopathy. Hereupon, dose-response applications with living donor plants demonstrate the validity of these principles for density-dependent phytotoxicity of allelochemicals produced and released by living plants (Avena sativa L., Secale cereale L., Triticum L. spp.), and reveal the use of such experiments for initial considerations about basic principles of allelopathy. Results confirm that nonlinearity applies to allelopathy, and the study of allelopathic effects in dose-response experiments allows for new and challenging insights into allelopathic interactions.

  3. Dose-response relationship of leukemia incidence among atomic bomb survivors and their controls by absorbed marrow dose and two types of leukemia Hiroshima and Nagasaki, October 1950 - December 1978

    International Nuclear Information System (INIS)

    Ishimaru, Toranosuke; Otake, Masanori; Ichimaru, Michito; Mikami, Motoko.

    1982-07-01

    Analysis of the relationship of the incidence of leukemia to gamma and neutron dose among atomic bomb survivors until 1971 has been reported previously by RERF. The present inquiry was prompted by the extension of case finding to 1978 and by the recent availability of new dose estimates for this fixed cohort. It is focused on the relationship of absorbed marrow dose of gamma rays and neutrons to the incidence of two types of leukemia in the fixed cohort of A-bomb survivors and their controls, the Life Span Study extended sample, in the period October 1950-December 1978. Three dose-response models have been fitted to the data on acute leukemia and chronic granulocytic leukemia. The relationship of the incidence of acute leukemia to gamma and neutron dose again suggests that the ''best'' fitting model involves a dependence on the square of the gamma dose and a linear dependence on neutrons. The estimated relative biological effectiveness (RBE) of neutrons in the induction of acute leukemia is approximately 44/√Dn(Dn = neutron dose) under this model. Based on the 95% confidence limits of the estimated RBE, the risk of this disease is estimated as 0.0026 - 0.0072 cases per million person-years per rem 2 of marrow dose. This analysis has failed, however, to produce a significant dose-response function for the incidence of chronic granulocytic leukemia in relation to the two kinds of radiation. (author)

  4. Nasal carriage of mecA-positive methicillin-resistant Staphylococcus aureus in pigs exhibits dose-response to zinc supplementation.

    Science.gov (United States)

    Amachawadi, Raghavendra G; Scott, Harvey M; Nitikanchana, Sureemas; Vinasco, Javier; Tokach, Mike D; Dritz, Steve S; Nelssen, Jim L; Goodband, Robert D; Nagaraja, Tiruvoor G

    2015-02-01

    Zinc (Zn) is often supplemented at elevated concentrations in swine diets, particularly in piglets, to prevent enteric infections and promote growth. Previous studies from Denmark have suggested a genetic linkage and a phenotypic association between Zn resistance, encoded by czrC, and methicillin-resistance conferred by mecA in Staphylococcus aureus. Such an association has not been reported in the U.S. swine population. We conducted an analysis of the effects of Zn, supplemented as zinc oxide (ZnO), on the nasal carriage of methicillin-resistant Staphylococcus aureus (MRSA) in nursery (n=40) and finisher pigs (n=40) enrolled in a nutritional study. Nasal swabs, collected from nursery and finisher pigs, were inoculated onto MRSA CHROMagar and presumptive MRSA colonies were tested for the presence of mecA and czrC genes by polymerase chain reaction. Zinc susceptibility was determined by the agar dilution method. The prevalence of mecA-positive MRSA was 10% (4/40) and 20% (8/40) among nursery and finisher pigs, respectively. Of the 12 mecA-positive S. aureus isolates, 7 had the czrC gene (58.3%) compared to none among the 68 mecA-negative isolates. The presence of both mecA (p=0.002) and czrC (p=0.006) genes were positively associated with higher levels of Zn supplementation. The median minimum inhibitory concentrations of Zn for czrC-positive and czrC-negative isolates were 12 and 2 mM, respectively (presistance among S. aureus in pigs.

  5. Model for dose-response with alternative change of sign

    International Nuclear Information System (INIS)

    Osovets, S.V.

    1998-01-01

    A new mathematical model of dose-response relationships is proposed, suitable for calculating stochastic effects of low level exposure. The corresponding differential equations are presented as well as their solution. (A.K.)

  6. Dose-response relationship of tryptophan with large neutral amino acids, and its impact on physiological responses in the chick model.

    Science.gov (United States)

    Bello, Alhassan Usman; Idrus, Zulkifli; Meng, Goh Yong; Narayan, Edward J; Farjam, Abdoreza Soleimani

    2018-05-01

    Tryptophan (Trp) has been associated with the regulation of several behavioral and physiological processes, through stimulation of serotonergic activity. Tryptophan utilization at the metabolic level is influenced by the competitive carrier system it shares with large neutral amino acids (LNAA). This study was carried out using meat-type chicken as a model, to investigate the dose response effects of Trp/LNAA on fear response (tonic immobility; TI) and hormonal responses, including corticosterone (CORT), serotonin (5-HT), triiodothyronine (T 3 ) and thyroxine (T 4 ). A total of 12 cages (48 birds) were assigned to each of the six experimental groups at 29-42 days of age. Experimental diets were formulated to have incremental levels of Trp/LNAA (0.025, 0.030, 0.035, 0.040, 0.045, and 0.050). The results revealed that, Trp/NAA had no significant effect on growth performance and TI of the birds. However, elevation of Trp/LNAA was concurred with a linear reduction in CORT (P < .0001, r 2  = 0.819) and linear increases in 5-HT (P < .0001, r 2  = 0.945), T 3 (P = .0003, r 2  = 0.403) and T 4 (P < .0001, r 2  = 0.937) levels. In conclusion, the results from the current study demonstrated that, although incremental levels of Trp/LNAA did not affect bird growth performance or fearfulness, it increased 5-HT, T 3 and T 4, and decreased CORT levels in a linear dose-dependent manner. Manipulation of Trp feeding levels could be applied to manage stressful conditions in birds. Copyright © 2018 Elsevier Inc. All rights reserved.

  7. Steep Dose-Response Relationship for Stage I Non-Small-Cell Lung Cancer Using Hypofractionated High-Dose Irradiation by Real-Time Tumor-Tracking Radiotherapy

    International Nuclear Information System (INIS)

    Onimaru, Rikiya; Fujino, Masaharu; Yamazaki, Koichi; Onodera, Yuya; Taguchi, Hiroshi; Katoh, Norio; Hommura, Fumihiro; Oizumi, Satoshi; Nishimura, Masaharu; Shirato, Hiroki

    2008-01-01

    Purpose: To investigate the clinical outcomes of patients with pathologically proven, peripherally located, Stage I non-small-cell lung cancer who had undergone stereotactic body radiotherapy using real-time tumor tracking radiotherapy during the developmental period. Methods and Materials: A total of 41 patients (25 with Stage T1 and 16 with Stage T2) were admitted to the study between February 2000 and June 2005. A 5-mm planning target volume margin was added to the clinical target volume determined with computed tomography at the end of the expiratory phase. The gating window ranged from ±2 to 3 mm. The dose fractionation schedule was 40 or 48 Gy in four fractions within 1 week. The dose was prescribed at the center of the planning target volume, giving more than an 80% dose at the planning target volume periphery. Results: For 28 patients treated with 48 Gy in four fractions, the overall actuarial survival rate at 3 years was 82% for those with Stage IA and 32% for those with Stage IB. For patients treated with 40 Gy in four fractions within 1 week, the overall actuarial survival rate at 3 years was 50% for those with Stage IA and 0% for those with Stage IB. A significant difference was found in local control between those with Stage IB who received 40 Gy vs. 48 Gy (p = 0.0015) but not in those with Stage IA (p = 0.5811). No serious radiation morbidity was observed with either dose schedule. Conclusion: The results of our study have shown that 48 Gy in four fractions within 1 week is a safe and effective treatment for peripherally located, Stage IA non-small-cell lung cancer. A steep dose-response curve between 40 and 48 Gy using a daily dose of 12 Gy delivered within 1 week was identified for Stage IB non-small-cell lung cancer in stereotactic body radiotherapy using real-time tumor tracking radiotherapy

  8. The relationship between zinc intake and serum/plasma zinc concentration in pregnant and lactating women: A systematic review with dose-response meta-analyses

    NARCIS (Netherlands)

    Hall Moran, V.; Skinner, A.L.; Warthon Medina, M.; Patel, S.; Dykes, F.; Souverein, O.W.; Dullemeijer, C.; Lowe, N.M.M.

    2012-01-01

    Recommendations for zinc intake during pregnancy and lactation vary widely across Europe. Using data on zinc intake and biomarkers of zinc status reported in randomized controlled trials (RCTs) and observational studies can provide estimates of dose–response relationships that may be used for

  9. Atopy patch tests in young adult patients with atopic dermatitis and controls: dose-response relationship, objective reading, reproducibility and clinical interpretation.

    Science.gov (United States)

    Bygum, Anette; Mortz, Charlotte Gotthard; Andersen, Klaus Ejner

    2003-01-01

    The clinical interpretation and reproducibility of atopy patch tests was studied in 23 selected young adult patients with atopic dermatitis and 25 healthy controls using standard inhalant allergens. Non-invasive measurements were used for objective assessment of test reactions and the participants were retested after 6 weeks. Ten of 19 (53%) evaluable patients with atopic dermatitis had at least one positive atopy patch test. However, there was no clear clinical relevance of the atopy patch test results when related to patient history and distribution of dermatitis. Reproducible and dose-dependent results were obtained with Dermatophagoides pteronyssinus, grass and cat with a reproducibility rate of 0.69 to 0.81 in patients and 0.60-0.96 in controls. A unique finding was a significant positive correlation between a positive atopy patch test, allergen dose and increase in transepidermal water loss and erythema, while measurement of capacitance did not distinguish between positive and negative reactions. The results of the present study do not support the routine use of atopy patch tests in the evaluation of adult patients with atopic dermatitis.

  10. Statistical and low dose response

    International Nuclear Information System (INIS)

    Thorson, M.R.; Endres, G.W.R.

    1981-01-01

    The low dose response and the lower limit of detection of the Hanford dosimeter depend upon may factors, including the energy of the radiation, whether the exposure is to be a single radiation or mixed fields, annealing cycles, environmental factors, and how well various batches of TLD materials are matched in the system. A careful statistical study and sensitivity analysis were performed to determine how these factors influence the response of the dosimeter system. Estimates have been included in this study of the standard deviation of calculated dose for various mixed field exposures from 0 to 1000 mrem

  11. Seamless integration of dose-response screening and flow chemistry: efficient generation of structure-activity relationship data of β-secretase (BACE1) inhibitors.

    Science.gov (United States)

    Werner, Michael; Kuratli, Christoph; Martin, Rainer E; Hochstrasser, Remo; Wechsler, David; Enderle, Thilo; Alanine, Alexander I; Vogel, Horst

    2014-02-03

    Drug discovery is a multifaceted endeavor encompassing as its core element the generation of structure-activity relationship (SAR) data by repeated chemical synthesis and biological testing of tailored molecules. Herein, we report on the development of a flow-based biochemical assay and its seamless integration into a fully automated system comprising flow chemical synthesis, purification and in-line quantification of compound concentration. This novel synthesis-screening platform enables to obtain SAR data on b-secretase (BACE1) inhibitors at an unprecedented cycle time of only 1 h instead of several days. Full integration and automation of industrial processes have always led to productivity gains and cost reductions, and this work demonstrates how applying these concepts to SAR generation may lead to a more efficient drug discovery process. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Recent results on the linearity of the dose-response relationship for radiation-induced mutations in human cells by low dose levels

    International Nuclear Information System (INIS)

    Traut, H.

    1987-01-01

    Five studies made by various authors in the last years are discussed, which are significant in that the response of human cells to low-dose irradiation is determined directly and not by extrapolation, and which also provide information on the mutagenic effects of low radiation doses. The results of these studies do not indicate any other than a linear response for induction of mutations by low-dose irradiation, nor are there any reasons observable for assuming the existence of a threshold dose. It is very likely therefore that cancer initiation at the low dose level also is characterized by a linear relationship. Although threshold dose levels cannot generally be excluded, and maybe are only too low to be detected by experiment, there is no plausible biophysical argument for assuming the existence of such microdose threshold. (orig./MG) [de

  13. A dose-response relationship for time to bone pain resolution after stereotactic body radiotherapy (SBRT) for renal cell carcinoma (RCC) bony metastases

    Energy Technology Data Exchange (ETDEWEB)

    Jhaveri, Pavan M. [Dept. of Radiology, Section of Radiation Oncology, Baylor College of Medicine, Houston (United States); Teh, Bin S.; Paulino, Arnold C.; Blanco, Angel I.; Butler, E. Brian [Dept. of Radiation Oncology, The Methodist Hospital/The Methodist Hospital Research Inst., Houston (United States)], email: bteh@tmhs.org; Lo, Simon S. [Dept. of Radiation Oncology, Univ. Hospitals Seidman Cancer Center, Case Western Reserve Univ., Cleveland (United States); Amato, Robert J. [Dept. of Internal Medicine, Div. of Oncology, Univ. of Texas Health Sciences Center, Houston (United States)

    2012-05-15

    Background. To investigate the utility of stereotactic body radiotherapy (SBRT) in the treatment of painful renal cell carcinoma (RCC) bone metastases, and for a possible dose effect on time to symptom relief. Material and methods. Eighteen patients with 24 painful osseous lesions from metastatic RCC were treated with SBRT. The most common treatment regimens were 24 Gy in 3 fractions and 40 Gy in 5 fractions. The times from treatment to first reported pain relief and time to symptom recurrence were evaluated. Median follow-up was 38 weeks (1-156 weeks). Results. Seventy-eight percent of all patients had pain relief. Patients treated with a BED > 85 Gy achieved faster and more durable pain relief compared to those treated with a BED < 85 Gy. There was decrease in time to pain relief after a change in treatment regimen to 8 Gy x 5 fractions (BED = 86). There was only one patient with grade 1 skin toxicity. No neurological or other toxicity was observed. Conclusions. SBRT can safely and effectively treat painful RCC bony metastases. There appears to be a relationship between radiation dose and time to stable pain relief.

  14. Radiosensitive xrs-5 and parental CHO cells show identical DNA neutral filter elution dose-response: implications for a relationship between cell radiosensitivity and induction of DNA double-strand breaks

    International Nuclear Information System (INIS)

    Iliakis, George; Okayasu, Ryuichi; Seaner, Robert

    1988-01-01

    The purpose of this work was to investigate a possible correlation between DNA elution dose-response and cell radiosensitivity. For this purpose neutral (pH 9.6) DNA filter elution dose-response curves were measured with radiosensitive xrs-5 and the parental Chinese hamster ovary (CHO) cells in the logarithmic and plateau phase of growth. No difference was observed between the two cell types in the DNA elution dose-response curves either in logarithmic or plateau phase, despite the dramatic differences in cell radiosensitivity. This observation indicates that the shape of the DNA elution dose-response curve and the shape of the cell survival curve are not causally related. It is proposed that the shoulder observed in the DNA elution dose-response curve reflects either partial release of DNA from chromatin, or cell cycle-specific alterations in the physicochemical properties of the DNA. (author)

  15. Dose-Response Calculator for ArcGIS

    Science.gov (United States)

    Hanser, Steven E.; Aldridge, Cameron L.; Leu, Matthias; Nielsen, Scott E.

    2011-01-01

    The Dose-Response Calculator for ArcGIS is a tool that extends the Environmental Systems Research Institute (ESRI) ArcGIS 10 Desktop application to aid with the visualization of relationships between two raster GIS datasets. A dose-response curve is a line graph commonly used in medical research to examine the effects of different dosage rates of a drug or chemical (for example, carcinogen) on an outcome of interest (for example, cell mutations) (Russell and others, 1982). Dose-response curves have recently been used in ecological studies to examine the influence of an explanatory dose variable (for example, percentage of habitat cover, distance to disturbance) on a predicted response (for example, survival, probability of occurrence, abundance) (Aldridge and others, 2008). These dose curves have been created by calculating the predicted response value from a statistical model at different levels of the explanatory dose variable while holding values of other explanatory variables constant. Curves (plots) developed using the Dose-Response Calculator overcome the need to hold variables constant by using values extracted from the predicted response surface of a spatially explicit statistical model fit in a GIS, which include the variation of all explanatory variables, to visualize the univariate response to the dose variable. Application of the Dose-Response Calculator can be extended beyond the assessment of statistical model predictions and may be used to visualize the relationship between any two raster GIS datasets (see example in tool instructions). This tool generates tabular data for use in further exploration of dose-response relationships and a graph of the dose-response curve.

  16. Dose response relationship at low doses

    International Nuclear Information System (INIS)

    Schull, W.J.

    1992-01-01

    The data that have accrued in Hiroshima and Nagasaki on the effects of ionizing radiation on the developing human brain are reviewed. Effects considered are severe mental retardation, lowered IQ scores, decline in school performance, seizures, other neuropsychological effects, and small head size. All these factors may be related to radiation doses received by the mother during pregnancy. (L.L.) 3 figs., tab., 7 refs

  17. Deviation from additivity in mixture toxicity: relevance of nonlinear dose-response relationships and cell line differences in genotoxicity assays with combinations of chemical mutagens and gamma-radiation.

    Science.gov (United States)

    Lutz, Werner K; Vamvakas, Spyros; Kopp-Schneider, Annette; Schlatter, Josef; Stopper, Helga

    2002-12-01

    Sublinear dose-response relationships are often seen in toxicity testing, particularly with bioassays for carcinogenicity. This is the result of a superimposition of various effects that modulate and contribute to the process of cancer formation. Examples are saturation of detoxification pathways or DNA repair with increasing dose, or regenerative hyperplasia and indirect DNA damage as a consequence of high-dose cytotoxicity and cell death. The response to a combination treatment can appear to be supra-additive, although it is in fact dose-additive along a sublinear dose-response curve for the single agents. Because environmental exposure of humans is usually in a low-dose range and deviation from linearity is less likely at the low-dose end, combination effects should be tested at the lowest observable effect levels (LOEL) of the components. This principle has been applied to combinations of genotoxic agents in various cellular models. For statistical analysis, all experiments were analyzed for deviation from additivity with an n-factor analysis of variance with an interaction term, n being the number of components tested in combination. Benzo[a]pyrene, benz[a]anthracene, and dibenz[a,c]anthracene were tested at the LOEL, separately and in combination, for the induction of revertants in the Ames test, using Salmonella typhimurium TA100 and rat liver S9 fraction. Combined treatment produced no deviation from additivity. The induction of micronuclei in vitro was investigated with ionizing radiation from a 137Cs source and ethyl methanesulfonate. Mouse lymphoma L5178Y cells revealed a significant 40% supra-additive combination effect in an experiment based on three independent replicates for controls and single and combination treatments. On the other hand, two human lymphoblastoid cell lines (TK6 and WTK1) as well as a pilot study with human primary fibroblasts from fetal lung did not show deviation from additivity. Data derived from one cell line should therefore

  18. Relationship of condylar position to disc position and morphology

    Energy Technology Data Exchange (ETDEWEB)

    Incesu, L.; Taskaya-Yilmaz, N. E-mail: nergizy@omu.edu.tr; Oeguetcen-Toller, M.; Uzun, E

    2004-09-01

    Introduction/objective: The purpose of this study was to assess whether condylar position, as depicted by magnetic resonance imaging, was an indicator of disc morphology and position. Methods and material: One hundred and twenty two TMJs of 61 patients with temporomandibular joint disorder were examined. Condylar position, disc deformity and degree of anterior disc displacement were evaluated by using magnetic resonance imaging. Results and discussion: Posterior condyle position was found to be the main feature of temporomandibular joints with slight and moderate anterior disc displacement. No statistical significance was found between the condylar position, and reducing and nonreducing disc positions. On the other hand, superior disc position was found to be statistically significant for centric condylar position. Conclusion: It was concluded that posterior condyle position could indicate anterior disc displacement whereas there was no relation between the position of condyle and the disc deformity.

  19. Dose-response relationship between probability of pathologic tumor control and glucose metabolic rate measured with FDG PET after preoperative chemoradiotherapy in locally advanced non-small-cell lung cancer

    International Nuclear Information System (INIS)

    Choi, Noah C.; Fischman, Alan J.; Niemierko, Andrzej; Ryu, Jin-Sook; Lynch, Thomas; Wain, John; Wright, Cameron; Fidias, Panos; Mathisen, Douglas

    2002-01-01

    Purpose: To determine the dose-response relationship between the probability of tumor control on the basis of pathologic tumor response (pTCP) and the residual metabolic rate of glucose (MRglc) in response to preoperative chemoradiotherapy in locally advanced non-small-cell lung cancer and to define the level of residual MRglc that corresponds to pTCP 50% and pTCP ≥95%. Methods and Materials: Quantitative dynamic 18F-2-fluoro-2-deoxy-D-glucose (18F-FDG) positron emission tomography was performed to measure regional MRglc at the primary lesion before and 2 weeks after preoperative chemoradiotherapy in an initial group of 13 patients with locally advanced NSCLC. A simplified kinetic method was developed subsequently from the initial dynamic study and used in the subsequent 16 patients. The preoperative radiotherapy programs consisted of (1) a split course of 42 Gy in 28 fractions within a period of 28 days using a twice-daily treatment schedule for Stage IIIA(N2) NSCLC (n=18) and (2) standard once-daily radiation schedule of 45-63 Gy in 25-35 fractions during a 5-7-week period (n=11). The preoperative chemotherapy regimens included two cycles of cisplatin, vinblastine, and 5-fluorouracil (n=24), cisplatin and etoposide (n=2), and cisplatin, Taxol, and 5-fluorouracil (n=3). Patients free of tumor progression after preoperative chemoradiotherapy underwent surgery. The degree of residual MRglc measured 2 weeks after preoperative chemoradiotherapy and 2 weeks before surgery was correlated with the pathologic tumor response. The relationship between MRglc and pTCP was modeled using logistic regression. Results: Of 32 patients entered into the study, 29 (16 men and 13 women; 30 lesions) were evaluated for the correlation between residual MRglc and pathologic tumor response. Three patients did not participate in the second study because of a steady decline in general condition. The median age was 60 years (range 42-78). One of the 29 patients had two separate lesions, and

  20. Dose response of bone-targeted enzyme replacement for murine hypophosphatasia.

    Science.gov (United States)

    Yadav, Manisha C; Lemire, Isabelle; Leonard, Pierre; Boileau, Guy; Blond, Laurent; Beliveau, Martin; Cory, Esther; Sah, Robert L; Whyte, Michael P; Crine, Philippe; Millán, José Luis

    2011-08-01

    Hypophosphatasia (HPP) features rickets or osteomalacia from tissue-nonspecific alkaline phosphatase (TNSALP) deficiency due to deactivating mutations within the ALPL gene. Enzyme replacement therapy with a bone-targeted, recombinant TNSALP (sALP-FcD(10), renamed ENB-0040) prevents manifestations of HPP when initiated at birth in TNSALP knockout (Akp2(-/-)) mice. Here, we evaluated the dose-response relationship of ENB-0040 to various phenotypic traits of Akp2(-/-) mice receiving daily subcutaneous (SC) injections of ENB-0040 from birth at 0.5, 2.0, or 8.2mg/kg for 43days. Radiographs, μCT, and histomorphometric analyses documented better bone mineralization with increasing doses of ENB-0040. We found a clear, positive correlation between ENB-0040 dose and prevention of mineralization defects of the feet, rib cage, lower limbs, and jaw bones. According to a dose-response model, the ED(80) (the dose that prevents bone defects in 80% of mice) was 3.2, 2.8 and 2.9mg/kg/day for these sites, respectively. Long bones seemed to respond to lower daily doses of ENB-0040. There was also a positive relationship between ENB-0040 dose and survival. Median survival, body weight, and bone length all improved with increasing doses of ENB-0040. Urinary PP(i) concentrations remained elevated in all treatment groups, indicating that while this parameter is a good biochemical marker for diagnosing HPP in patients, it may not be a good follow up marker for evaluating response to treatment when administering bone-targeted TNSALP to mice. These dose-response relationships strongly support the pharmacological efficacy of ENB-0040 for HPP, and provide the experimental basis for the therapeutic range of ENB-0040 chosen for clinical trials. Copyright © 2011 Elsevier Inc. All rights reserved.

  1. Dose-response meta-analysis of differences in means

    Directory of Open Access Journals (Sweden)

    Alessio Crippa

    2016-08-01

    Full Text Available Abstract Background Meta-analytical methods are frequently used to combine dose-response findings expressed in terms of relative risks. However, no methodology has been established when results are summarized in terms of differences in means of quantitative outcomes. Methods We proposed a two-stage approach. A flexible dose-response model is estimated within each study (first stage taking into account the covariance of the data points (mean differences, standardized mean differences. Parameters describing the study-specific curves are then combined using a multivariate random-effects model (second stage to address heterogeneity across studies. Results The method is fairly general and can accommodate a variety of parametric functions. Compared to traditional non-linear models (e.g. E max, logistic, spline models do not assume any pre-specified dose-response curve. Spline models allow inclusion of studies with a small number of dose levels, and almost any shape, even non monotonic ones, can be estimated using only two parameters. We illustrated the method using dose-response data arising from five clinical trials on an antipsychotic drug, aripiprazole, and improvement in symptoms in shizoaffective patients. Using the Positive and Negative Syndrome Scale (PANSS, pooled results indicated a non-linear association with the maximum change in mean PANSS score equal to 10.40 (95 % confidence interval 7.48, 13.30 observed for 19.32 mg/day of aripiprazole. No substantial change in PANSS score was observed above this value. An estimated dose of 10.43 mg/day was found to produce 80 % of the maximum predicted response. Conclusion The described approach should be adopted to combine correlated differences in means of quantitative outcomes arising from multiple studies. Sensitivity analysis can be a useful tool to assess the robustness of the overall dose-response curve to different modelling strategies. A user-friendly R package has been developed to facilitate

  2. Dose-response analysis using R

    DEFF Research Database (Denmark)

    Ritz, Christian; Baty, Florent; Streibig, Jens Carl

    2015-01-01

    Dose-response analysis can be carried out using multi-purpose commercial statistical software, but except for a few special cases the analysis easily becomes cumbersome as relevant, non-standard output requires manual programming. The extension package drc for the statistical environment R provides...

  3. Dose-response curves from incomplete data

    International Nuclear Information System (INIS)

    Groer, P.G.

    1978-01-01

    Frequently many different responses occur in populations (animal or human) exposed to ionizing radiation. To obtain a dose-response curve, the exposed population is first divided into sub-groups whose members received the same radiation dose. To estimate the response, the fraction of subjects in each sub-group that showed the particular response of interest is determined. These fractions are plotted against dose to give the dose-response curve. This procedure of plotting the fractions versus the radiation dose is not the correct way to estimate the time distribution for a particular response at the different dose levels. Other observed responses competed for the individuals in the exposed population and therefore prevented manifestation of the complete information on the response-time distribution for one specific response. Such data are called incomplete in the statistical literature. A procedure is described which uses the by now classical Kaplan-Meier estimator, to establish dose-response curves from incomplete data under the assumption that the different observed responses are statistically independent. It is demonstrated that there is insufficient information in the observed survival functions to estimate the time distribution for one particular response if the assumption of independence is dropped. In addition, it is not possible to determine from the data (i.e. type of response and when it occurred) whether or not the different response-time distributions are independent. However, it is possible to give sharp bounds between which the response has to lie. This implies that for incomplete data, only a 'dose-response band' can be established if independence of the competing responses cannot be assumed. Examples are given using actual data to illustrate the estimation procedures

  4. Inflation and Growth: Positive or Negative Relationship?

    Science.gov (United States)

    Berument, Hakan; Inamlik, Ali; Olgun, Hasan

    This study has been motivated by two developments. Firstly, by the vast literature on the relationship between inflation and growth which is abundantly endowed with diverse theoretical explanations and contradictory evidence and by the unique experience of the Turkish economy with inflation and growth. A preliminary examination of the Turkish data pointed to a negative relation between inflation and growth. Moreover, there is a unanimous agreement among the students of the Turkish economy that many factors have contributed to inflation in this country. In view of these facts this paper employs a VAR model which will enable us to identify the sources of the shocks and control for external factors. In addition VAR models have a high predictive power and enable the researcher to observe the impulse response functions. The study employs Generalised Impulse Response analysis. In the empirical experiments oil prices, money supply, government spending and taxes have been taken as the most likely determinants of inflation. The study shows that there is a negative relationship between inflation and output growth in Turkey and that the underlying explanatory factor is the real exchange rate. This result is robust.

  5. Influences of mechanical exposure biographies on physical capabilities of workers from automotive industry - a study on possible dose-response relationships and consequences for short and long term job rotation.

    Science.gov (United States)

    Rademacher, Holger; Bruder, Ralph; Sinn-Behrendt, Andrea; Landau, Kurt

    2012-01-01

    This paper describes a field study in production areas of a vehicle manufacturing plant, where 106 male workers (aged from 20 to 63 years) were examined and interviewed by the authors. Aim of study was to identify relationships between specific physical worker capabilities and doses of mechanical exposures using self-developed standardized questionnaires as well as a battery of work-specific tests. The dependent variables are different "physical capabilities", classified using a five-point rating scale with regard to the grade of limitation of the respective capability. Independent variables are "age" and specific "mechanical exposures". Several exposures were combined and multiplied with their respective durations in order to determine doses on three different body regions - back, shoulder-neck and upper limbs. There are significant positive correlations between "age" and "dose of mechanical exposure on back/shoulder-neck/upper limbs region". The analysis of the relationship between dose of exposure and different capabilities to lift or reposition loads (with variable weight) shows weak significant correlations for all three body regions. Data analysis shows no significant correlations between any dose of mechanical exposure and capabilities to work in awkward body postures.These results should be considered in age management programs when scheduling future employee assignments to workplaces, especially for production systems where manual handling tasks are dominant.

  6. Dose Response Association between Physical Activity and Biological, Demographic, and Perceptions of Health Variables

    Directory of Open Access Journals (Sweden)

    Paul D. Loprinzi

    2013-08-01

    Full Text Available Background: Few population-based studies have examined the association between physical activity (PA and cardiovascular disease risk factors, demographic variables, and perceptions of health status, and we do not have a clear understanding of the dose-response relationship among these variables. Methods: Data from the 2003-2006 National Health and Nutrition Examination Survey was used to examine the dose-response relationship between objectively measured PA and metabolic syndrome (and its individual cardiovascular disease risk factors, demographic variables, and perceptions of health. After exclusions, 5,538 participants 18 years or older were included in the present study, with 2,538 participants providing fasting glucose and 2,527 providing fasting triglyceride data. PA was categorized into deciles. Results: Overall, the health benefits showed a general pattern of increase with each increasing levels of PA. Of the ten PA classifications examined, participants in the highest moderate-to-vigorous physical activity (MVPA category (at least 71 min/day had the lowest odds of developing metabolic syndrome. Conclusion: At a minimum, sedentary adults should strive to meet current PA guidelines (i.e., 150 min/week of MVPA, with additional positive benefits associated with engaging in three times this level of PA.

  7. Dose-response relationship of induction kinetics of In vivo DNA damage and repair in mouse leukocytes exposed to gamma radiation; Relacion dosis-respuesta de la cinetica de induccion de dano y reparacion del ADN In vivo en leucocitos de raton expuestos a radiacion gamma

    Energy Technology Data Exchange (ETDEWEB)

    Mendiola C, M.T.; Morales, R.P. [Instituto Nacional de Investigaciones Nucleares, Gerencia de Investigacion Basica, Departamento de Biologia, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    2000-07-01

    The Unicellular electrophoresis in gel technique is a useful tool in the determination of simple ruptures and labile sites to the alkali in DNA of eucariontes cells. The determination of the induction kinetics of damage and repair of DNA can give more information. The objective of this work was to determine whether the analysis of the area under the damage/repair induction kinetics curve in comets percent or the comets frequency in the two peaks of maximum induction is adequate for determining the dose-response relationship. The mice were exposed at the doses of 0.5, 1.0, 2.0 Gy. (Author)

  8. Public green spaces and positive mental health - investigating the relationship between access, quantity and types of parks and mental wellbeing.

    Science.gov (United States)

    Wood, Lisa; Hooper, Paula; Foster, Sarah; Bull, Fiona

    2017-11-01

    Associations between parks and mental health have typically been investigated in relation to the presence or absence of mental illness. This study uses a validated measure of positive mental health and data from RESIDential Environments (RESIDE) Project to investigate the association between the presence, amount and attributes of public green space in new greenfield neighbourhood developments and the mental health of local residents (n = 492). Both the overall number and total area of public green spaces were significantly associated with greater mental wellbeing, and findings support a dose-response relationship. Positive mental health was not only associated with parks with a nature focus, but also with green spaces characterised by recreational and sporting activity. The study demonstrates that adequate provision of public green space in local neighbourhoods and within walking distance is important for positive mental health. Copyright © 2017. Published by Elsevier Ltd.

  9. [How children show positive and negative relationships on their drawings].

    Science.gov (United States)

    Gramel, Sabine

    2005-01-01

    This study analyses, whether pictures of children showing a positive relationship are significantly different from those showing a negative one with respect to several criteria. The study involved a random selection of 45 children aged 4;6 to 11;6 years. The children painted a picture with themselves and a person they liked and a picture of themselves with someone they disliked. For the most part, the children drew pictures of themselves with peers both with respect to positive as well as negative images. In an interview afterwards, the children specified the criteria in their drawings by which the quality of the particular relationship can be identified. Positive and negative relationship paintings differ in the character of activity described. The sun as an element in children's paintings is painted not more frequent on positive compared to negative pictures. The colour black is used more often in the drawings signifying negative relationships. While girls used more colour in negative relationship drawings, boys used more colour in the positive ones. There was no significant difference in the use of favourite colours and decorative elements between the two groups. Only in negative relationship drawings people were looking away from each other. Smiling individuals were more common in the positive relationship pictures and in pictures painted by the 6 to 8 year olds. A greater distance between the individuals emerged on negative relationship drawings of the girls.

  10. Dose-response of women's health-related quality of life (HRQoL) and life satisfaction to physical activity.

    Science.gov (United States)

    Eime, Rochelle; Harvey, Jack; Payne, Warren

    2014-02-01

    To examine the dose-response relationship between health related quality of life (HRQoL) and life satisfaction (outcomes) and duration of recreational physical activity (exposure). Further, to explore whether these relationships depend on type of physical activity (PA). 793 Australian rural-living women self-reported on duration of recreational PA; HRQoL via SF-36 Mental Component Summary (MCS) and Physical Component Summary (PCS); and a life satisfaction scale. ANOVAs and ANCOVAs investigated differences in outcomes (MCS, PCS, and life satisfaction) between tertiles of exposure to recreational PA, and types of PA (club sport, gymnasium, walking), with adjustment for potential confounders. A significant positive dose-response relationship was found between PCS and level of PA. Furthermore, this relationship depended on type of PA, with club-sport participants recording higher PCS than non-club-sport participants in all but the highest tertile of exposure. Life satisfaction and MCS were not significantly related to level of PA. Physical health was positively associated with level of recreational PA, with club sport participation contributing greater benefits at low to moderate exposures than participation in gymnasium or walking activities.

  11. Empathy in intimate relationships : The role of positive illusions

    NARCIS (Netherlands)

    Dijkstra, Pieternel; Barelds, Dick P.H.; Groothof, Hinke A.K.; Van Bruggen, Marnix

    2014-01-01

    Previous studies have shown empathy to be an important aspect of a high quality intimate relationship. Likewise, positive illusions about a partner's characteristics have been shown to contribute to relationship quality. The present study connects these issues by examining the degree to which

  12. Neuromuscular dose-response studies: determining sample size.

    Science.gov (United States)

    Kopman, A F; Lien, C A; Naguib, M

    2011-02-01

    Investigators planning dose-response studies of neuromuscular blockers have rarely used a priori power analysis to determine the minimal sample size their protocols require. Institutional Review Boards and peer-reviewed journals now generally ask for this information. This study outlines a proposed method for meeting these requirements. The slopes of the dose-response relationships of eight neuromuscular blocking agents were determined using regression analysis. These values were substituted for γ in the Hill equation. When this is done, the coefficient of variation (COV) around the mean value of the ED₅₀ for each drug is easily calculated. Using these values, we performed an a priori one-sample two-tailed t-test of the means to determine the required sample size when the allowable error in the ED₅₀ was varied from ±10-20%. The COV averaged 22% (range 15-27%). We used a COV value of 25% in determining the sample size. If the allowable error in finding the mean ED₅₀ is ±15%, a sample size of 24 is needed to achieve a power of 80%. Increasing 'accuracy' beyond this point requires increasing greater sample sizes (e.g. an 'n' of 37 for a ±12% error). On the basis of the results of this retrospective analysis, a total sample size of not less than 24 subjects should be adequate for determining a neuromuscular blocking drug's clinical potency with a reasonable degree of assurance.

  13. TESS-based dose-response using pediatric clonidine exposures

    International Nuclear Information System (INIS)

    Benson, Blaine E.; Spyker, Daniel A.; Troutman, William G.; Watson, William A.

    2006-01-01

    Objective: The toxic and lethal doses of clonidine in children are unclear. This study was designed to determine whether data from the American Association of Poison Control Centers Toxic Exposure Surveillance System (TESS) could be utilized to determine a dose-response relationship for pediatric clonidine exposure. Methods: 3458 single-substance clonidine exposures in children <6 years of age reported to TESS from January 2000 through December 2003 were examined. Dose ingested, age, and medical outcome were available for 1550 cases. Respiratory arrest cases (n = 8) were classified as the most severe of the medical outcome categories (Arrest, Major, Moderate, Mild, and No effect). Exposures reported as a 'taste or lick' (n = 51) were included as a dose of 1/10 of the dosage form involved. Dose ranged from 0.4 to 1980 (median 13) μg/kg. Weight was imputed based on a quadratic estimate of weight for age. Dose certainty was coded as exact (26% of cases) or not exact (74%). Medical outcome (response) was examined via logistic regression using SAS JMP (release 5.1). Results: The logistic model describing medical outcome (P < 0.0001) included Log dose/kg (P 0.0000) and Certainty (P = 0.045). Conclusion: TESS data can provide the basis for a statistically sound description of dose-response for pediatric clonidine poisoning exposures

  14. TESS-based dose-response using pediatric clonidine exposures.

    Science.gov (United States)

    Benson, Blaine E; Spyker, Daniel A; Troutman, William G; Watson, William A

    2006-06-01

    The toxic and lethal doses of clonidine in children are unclear. This study was designed to determine whether data from the American Association of Poison Control Centers Toxic Exposure Surveillance System (TESS) could be utilized to determine a dose-response relationship for pediatric clonidine exposure. 3,458 single-substance clonidine exposures in children TESS from January 2000 through December 2003 were examined. Dose ingested, age, and medical outcome were available for 1550 cases. Respiratory arrest cases (n = 8) were classified as the most severe of the medical outcome categories (Arrest, Major, Moderate, Mild, and No effect). Exposures reported as a "taste or lick" (n = 51) were included as a dose of 1/10 of the dosage form involved. Dose ranged from 0.4 to 1980 (median 13) microg/kg. Weight was imputed based on a quadratic estimate of weight for age. Dose certainty was coded as exact (26% of cases) or not exact (74%). Medical outcome (response) was examined via logistic regression using SAS JMP (release 5.1). The logistic model describing medical outcome (P TESS data can provide the basis for a statistically sound description of dose-response for pediatric clonidine poisoning exposures.

  15. Positive illusions about a partner's physical attractiveness and relationship quality

    NARCIS (Netherlands)

    Barelds, Dick P. H.; Dijkstra, Pieternel

    The present research examined the existence of positive illusions about a partner's physical attractiveness and its relations to relationship quality. Positive illusions were assumed to exist when individuals rated their partner as more attractive than their partner rated him or herself. In two

  16. Skull base chordomas: analysis of dose-response characteristics

    International Nuclear Information System (INIS)

    Niemierko, Andrzej; Terahara, Atsuro; Goitein, Michael

    1997-01-01

    parameters of the time-dose-response relationship for the analyzed group of patients. For example, the maximum likelihood estimates of surviving fraction at 2Gy (SF 2 ) are 0.47 with 95% confidence limits of [0.45-0.49] for male and 0.53 [0.51-0.55] for female, with the coefficient of inter-patient variation in SF 2 of 4.3%. The density of clonogens was estimated to be 10 8.2 clonogens per cubic centimeter. In effect, the slope of the dose-response curve, γ 50 , was estimated to be 2.7 [1.9-3.2] for both male and female, and the ED 50 doses to be 67Gy and 73Gy respectively. Skull base chordomas of the female patients seemed to be not only more resistant to radiation but also recurring faster than that for male patients (the maximum likelihood estimates of the Weibull shape parameter β are 2.6 for female and 1.7 for male patients). Conclusions: This analysis revealed several clinically important characteristics of radioresponsiveness of skull base chordomas. The comprehensive patient data obtained using three-dimensional treatment planning system allowed us to demonstrate and quantify the existence of dose-response and dose-volume relationships. In consequence, we are able to estimate prospectively the individual's probability of staying recurrence-free and her/his overall survival characteristics as a function of the applied three-dimensional dose distribution and time after treatment. Based on the analysis our treatment protocols have been modified to account for differences in radiosensitivity between female and male patients

  17. Addressing model uncertainty in dose-response: The case of chloroform

    International Nuclear Information System (INIS)

    Evans, J.S.

    1994-01-01

    This paper discusses the issues involved in addressing model uncertainty in the analysis of dose-response relationships. A method for addressing model uncertainty is described and applied to characterize the uncertainty in estimates of the carcinogenic potency of chloroform. The approach, which is rooted in Bayesian concepts of subjective probability, uses probability trees and formally-elicited expert judgments to address model uncertainty. It is argued that a similar approach could be used to improve the characterization of model uncertainty in the dose-response relationships for health effects from ionizing radiation

  18. The Relationship Between Depression And Positive Signs In Chronic Schizophrenia

    Directory of Open Access Journals (Sweden)

    Bahaoddini S S

    2004-06-01

    Full Text Available Background: The results of studies about relationship between depression and positive signs in schizophrenia are controversial and clarifying the nature of this association may be difficult. The aim of present study is to investigate relationship between depressive symptoms and positive signs, in acute phase of patients with chronic schizophrenia, who have been admitted in Roozbeh Hospital. Materials and Methods: Assessments were performed using the Beck depression Inventory for depression (subjectively and positive and negative syndrome scale (PANSS for psychotic symptoms. Results: The results demonstrated a significant correlation between depressive symptoms and positive signs in these patients. Also, a significant correlation existed between depression and these items: delusions, hallucinatory behavior, excitement, hostility. Conclusion: depressive symptoms and positive signs in schizophrenia may have a common underlying pathophysiological origin.

  19. Buyer-Supplier Relationships and Power Position: Interchaining

    Directory of Open Access Journals (Sweden)

    Hebatollah Morsy

    2017-02-01

    Full Text Available According to several studies, power and interdependence play a considerable role in understanding the buyer–supplier relationships, yet, empirical research is still limited. Also, the nature of the buyer-supplier relationship and managing them might vary based on the power position of buyers and suppliers. Few studies focused on the reason behind this interrelation and strong influence of power on the buyer-supplier relationships. Thus, the purpose of this study is to gain better understanding and try to identify how power position and buyer-supplier relationships are interrelated, and whether there are common determinants and/or characteristics behind this strong bond between the two concepts. Both transaction cost analysis theory and social exchange theory were integrated in building the argument. Regarding the methodology, qualitative exploratory research design was employed by using multiple-case study as the main research method, where three multinational Egyptian organizations were selected. Moreover, data was collected using individual in-depth interviews, and analyzed through coding and cross case analysis techniques. The results showed that there are common factors that influence both buyer-supplier relationship characteristics and power position attributes. And according, the findings helped in pointing out a new lens of discussing and investigating the bond between buyer-supplier relationships ad power in research.

  20. Relations among Positive Parenting, parent-child Relationship, and Empathy

    DEFF Research Database (Denmark)

    Wu, Liyun; Zhang, Xingli; Shi, Jiannong

    This study demonstrated relations among 2 features of positive parenting——supportive responsiveness to distress and warmth ,parent-child relationship and empathy.171 children aged 8-10 years (mean age = 9.31 years, 89 girls) participated in the study.In school,participants completed Empathic......,Prosocial Response to Another’s Distress Scale,Parental Acceptance-Rejection Questionnaire, Coping with Children’s Negative Emotions Questionaire,Network of Relationships Inventory. Results showed that: (1)Parents' supportive responsiveness to distress, but not warmth, predicted children's empathy.(2)Near parent-child...... parent-child relationship....

  1. Dose-response characteristics of an amorphous silicon EPID

    International Nuclear Information System (INIS)

    Winkler, Peter; Hefner, Alfred; Georg, Dietmar

    2005-01-01

    Electronic portal imaging devices (EPIDs) were originally developed for the purpose of patient setup verification. Nowadays, they are increasingly used as dosimeters (e.g., for IMRT verification and linac-specific QA). A prerequisite for any clinical dosimetric application is a detailed understanding of the detector's dose-response behavior. The aim of this study is to investigate the dosimetric properties of an amorphous silicon EPID (Elekta IVIEWGT) with respect to three photon beam qualities: 6, 10, and 25 MV. The EPID showed an excellent temporal stability on short term as well as on long term scales. The stability throughout the day was strongly influenced by warming up, which took several hours and affected EPID response by 2.5%. Ghosting effects increased the sensitivity of the EPID. They became more pronounced with decreasing time intervals between two exposures as well as with increasing dose. Due to ghosting, changes in pixel sensitivity amounted up to 16% (locally) for the 25 MV photon beam. It was observed that the response characteristics of our EPID depended on dose as well as on dose rate. Doubling the dose rate increased the EPID sensitivity by 1.5%. This behavior was successfully attributed to a dose per frame effect, i.e., a nonlinear relationship between the EPID signal and the dose which was delivered to the panel between two successive readouts. The sensitivity was found to vary up to 10% in the range of 1 to 1000 monitor units. This variation was governed by two independent effects. For low doses, the EPID signal was reduced due to the linac's changing dose rate during startup. Furthermore, the detector reading was influenced by intrabeam variations of EPID sensitivity, namely, an increase of detector response during uniform exposure. For the beam qualities which were used, the response characteristics of the EPID did not depend on energy. Differences in relative dose-response curves resulted from energy dependent temporal output

  2. Bayesian Dose-Response Modeling in Sparse Data

    Science.gov (United States)

    Kim, Steven B.

    This book discusses Bayesian dose-response modeling in small samples applied to two different settings. The first setting is early phase clinical trials, and the second setting is toxicology studies in cancer risk assessment. In early phase clinical trials, experimental units are humans who are actual patients. Prior to a clinical trial, opinions from multiple subject area experts are generally more informative than the opinion of a single expert, but we may face a dilemma when they have disagreeing prior opinions. In this regard, we consider compromising the disagreement and compare two different approaches for making a decision. In addition to combining multiple opinions, we also address balancing two levels of ethics in early phase clinical trials. The first level is individual-level ethics which reflects the perspective of trial participants. The second level is population-level ethics which reflects the perspective of future patients. We extensively compare two existing statistical methods which focus on each perspective and propose a new method which balances the two conflicting perspectives. In toxicology studies, experimental units are living animals. Here we focus on a potential non-monotonic dose-response relationship which is known as hormesis. Briefly, hormesis is a phenomenon which can be characterized by a beneficial effect at low doses and a harmful effect at high doses. In cancer risk assessments, the estimation of a parameter, which is known as a benchmark dose, can be highly sensitive to a class of assumptions, monotonicity or hormesis. In this regard, we propose a robust approach which considers both monotonicity and hormesis as a possibility. In addition, We discuss statistical hypothesis testing for hormesis and consider various experimental designs for detecting hormesis based on Bayesian decision theory. Past experiments have not been optimally designed for testing for hormesis, and some Bayesian optimal designs may not be optimal under a

  3. Relationship between positive mental health and appreciation in Korean individuals.

    Science.gov (United States)

    Lim, Young-Jin

    2017-06-01

    Appreciation is a key component of subjective well-being and may contribute to positive mental health. Few studies have examined relationships between specific aspects of appreciation and the 3 dimensions of positive mental health, and thus, the aim of this study was to identify associations between aspects of appreciation and positive mental health. Appreciation and positive mental health were measured in 266 Korean university students (50% females) using the Appreciation Inventory and the Mental Health Continuum-Short Form. The results obtained showed that Have Focus significantly predicted Emotional Well-being; Have Focus and Loss/Adversity significantly predicted Social Well-being and Have Focus, Expression and Nature/Daily Life significantly predicted Psychological Well-being. The implications of results that might enable positive mental health to be enhanced are discussed. © 2015 International Union of Psychological Science.

  4. Dose response of subcutaneous GLP-1 infusion in patients with type 2 diabetes

    DEFF Research Database (Denmark)

    Torekov, Signe Sørensen; Kipnes, M S; Harley, R E

    2011-01-01

    To evaluate the dose-response relationship of the recombinant glucagon-like peptide-1 (7-36) amide (rGLP-1) administered by continuous subcutaneous infusion (CSCI) in subjects with type 2 diabetes, with respect to reductions in fasting, postprandial and 11-h serum glucose profiles....

  5. Biphasic dose responses in biology, toxicology and medicine: Accounting for their generalizability and quantitative features

    International Nuclear Information System (INIS)

    Calabrese, Edward J.

    2013-01-01

    The most common quantitative feature of the hormetic-biphasic dose response is its modest stimulatory response which at maximum is only 30–60% greater than control values, an observation that is consistently independent of biological model, level of organization (i.e., cell, organ or individual), endpoint measured, chemical/physical agent studied, or mechanism. This quantitative feature suggests an underlying “upstream” mechanism common across biological systems, therefore basic and general. Hormetic dose response relationships represent an estimate of the peak performance of integrative biological processes that are allometrically based. Hormetic responses reflect both direct stimulatory or overcompensation responses to damage induced by relatively low doses of chemical or physical agents. The integration of the hormetic dose response within an allometric framework provides, for the first time, an explanation for both the generality and the quantitative features of the hormetic dose response. -- Highlights: •The hormetic stimulation is at maximum 30–60% greater than control responses. •Hormesis is a measure of biological performance and plasticity. •The hormetic response is evolutionary based and highly generalizable. -- This paper provides a biologically based explanation for the generalizability/quantitative features of the hormetic dose response, representing a fundamental contribution to the field

  6. An adaptive two-stage dose-response design method for establishing proof of concept.

    Science.gov (United States)

    Franchetti, Yoko; Anderson, Stewart J; Sampson, Allan R

    2013-01-01

    We propose an adaptive two-stage dose-response design where a prespecified adaptation rule is used to add and/or drop treatment arms between the stages. We extend the multiple comparison procedures-modeling (MCP-Mod) approach into a two-stage design. In each stage, we use the same set of candidate dose-response models and test for a dose-response relationship or proof of concept (PoC) via model-associated statistics. The stage-wise test results are then combined to establish "global" PoC using a conditional error function. Our simulation studies showed good and more robust power in our design method compared to conventional and fixed designs.

  7. Radiation Dose-Response Model for Locally Advanced Rectal Cancer After Preoperative Chemoradiation Therapy

    DEFF Research Database (Denmark)

    Appelt, A. L.; Ploen, J.; Vogelius, I. R.

    2013-01-01

    estimated radiation dose-response curves for various grades of tumor regression after preoperative CRT. Methods and Materials: A total of 222 patients, treated with consistent chemotherapy and radiation therapy techniques, were considered for the analysis. Radiation therapy consisted of a combination...... of external-beam radiation therapy and brachytherapy. Response at the time of operation was evaluated from the histopathologic specimen and graded on a 5-point scale (TRG1-5). The probability of achieving complete, major, and partial response was analyzed by ordinal logistic regression, and the effect...... of including clinical parameters in the model was examined. The radiation dose-response relationship for a specific grade of histopathologic tumor regression was parameterized in terms of the dose required for 50% response, D-50,D-i, and the normalized dose-response gradient, gamma(50,i). Results: A highly...

  8. Predicting Positive and Negative Relationships in Large Social Networks.

    Directory of Open Access Journals (Sweden)

    Guan-Nan Wang

    Full Text Available In a social network, users hold and express positive and negative attitudes (e.g. support/opposition towards other users. Those attitudes exhibit some kind of binary relationships among the users, which play an important role in social network analysis. However, some of those binary relationships are likely to be latent as the scale of social network increases. The essence of predicting latent binary relationships have recently began to draw researchers' attention. In this paper, we propose a machine learning algorithm for predicting positive and negative relationships in social networks inspired by structural balance theory and social status theory. More specifically, we show that when two users in the network have fewer common neighbors, the prediction accuracy of the relationship between them deteriorates. Accordingly, in the training phase, we propose a segment-based training framework to divide the training data into two subsets according to the number of common neighbors between users, and build a prediction model for each subset based on support vector machine (SVM. Moreover, to deal with large-scale social network data, we employ a sampling strategy that selects small amount of training data while maintaining high accuracy of prediction. We compare our algorithm with traditional algorithms and adaptive boosting of them. Experimental results of typical data sets show that our algorithm can deal with large social networks and consistently outperforms other methods.

  9. Predicting Positive and Negative Relationships in Large Social Networks.

    Science.gov (United States)

    Wang, Guan-Nan; Gao, Hui; Chen, Lian; Mensah, Dennis N A; Fu, Yan

    2015-01-01

    In a social network, users hold and express positive and negative attitudes (e.g. support/opposition) towards other users. Those attitudes exhibit some kind of binary relationships among the users, which play an important role in social network analysis. However, some of those binary relationships are likely to be latent as the scale of social network increases. The essence of predicting latent binary relationships have recently began to draw researchers' attention. In this paper, we propose a machine learning algorithm for predicting positive and negative relationships in social networks inspired by structural balance theory and social status theory. More specifically, we show that when two users in the network have fewer common neighbors, the prediction accuracy of the relationship between them deteriorates. Accordingly, in the training phase, we propose a segment-based training framework to divide the training data into two subsets according to the number of common neighbors between users, and build a prediction model for each subset based on support vector machine (SVM). Moreover, to deal with large-scale social network data, we employ a sampling strategy that selects small amount of training data while maintaining high accuracy of prediction. We compare our algorithm with traditional algorithms and adaptive boosting of them. Experimental results of typical data sets show that our algorithm can deal with large social networks and consistently outperforms other methods.

  10. Health effects of low doses at low dose rates: dose-response relationship modeling in a cohort of workers of the nuclear industry; Effets sanitaires des faibles doses a faibles debits de dose: modelisation de la relation dose-reponse dans une cohorte de travailleurs du nucleaire

    Energy Technology Data Exchange (ETDEWEB)

    Metz-Flamant, Camille

    2011-09-19

    The aim of this thesis is to contribute to a better understanding of the health effects of chronic external low doses of ionising radiation. This work is based on the French cohort of CEA-AREVA NC nuclear workers. The mains stages of this thesis were (1) conducting a review of epidemiological studies on nuclear workers, (2) completing the database and performing a descriptive analysis of the cohort, (3) quantifying risk by different statistical methods and (4) modelling the exposure-time-risk relationship. The cohort includes monitored workers employed more than one year between 1950 and 1994 at CEA or AREVA NC companies. Individual annual external exposure, history of work, vital status and causes of death were reconstructed for each worker. Standardized mortality ratios using French national mortality rates as external reference were computed. Exposure-risk analysis was conducted in the cohort using the linear excess relative risk model, based on both Poisson regression and Cox model. Time dependent modifying factors were investigated by adding an interaction term in the model or by using exposure time windows. The cohort includes 36, 769 workers, followed-up until age 60 in average. During the 1968- 2004 period, 5, 443 deaths, 2, 213 cancers, 62 leukemia and 1, 314 cardiovascular diseases were recorded. Among the 57% exposed workers, the mean cumulative dose was 21.5 milli-sieverts (mSv). A strong Healthy Worker Effect is observed in the cohort. Significant elevated risks of pleura cancer and melanoma deaths were observed in the cohort but not associated with dose. No significant association was observed with solid cancers, lung cancer and cardiovascular diseases. A significant dose-response relationship was observed for leukemia excluding chronic lymphatic leukemia, mainly for doses received less than 15 years before and for yearly dose rates higher than 10 mSv. This PhD work contributes to the evaluation of risks associated to chronic external radiation

  11. Skin Prick Tests and Dose Response Relationship between ...

    African Journals Online (AJOL)

    Subjects and Methods: The study was carried out on 60 bakers working at different bakeries at Dekernis, Dakahlia Governorate, Egypt; and 30 control subjects. All participants were submitted to a self administered questionnaire on respiratory symptoms, general medical examination, chest examination; spirometry and SPT.

  12. Dose-Response Relationship of Phototherapy for Hyperbilirubinemia

    DEFF Research Database (Denmark)

    Vandborg, Pernille Kure; Hansen, Bo Moelholm; Greisen, Gorm

    2012-01-01

    Using light-emitting diodes during conventional phototherapy, it is possible to reduce the distance from light source to infant, thus increasing light irradiance. The objective of this study was to search for a "saturation point" (ie, an irradiation level above which there is no further decrease ...

  13. Dose-response relationships of acute exposure to sulfur dioxide

    International Nuclear Information System (INIS)

    Englehardt, F.R.; Holliday, M.G.

    1981-01-01

    Acute toxicity effects of sulphur dioxide are reviewed, and the derivation of a dose-lethality curve (presented as LC 50 vs. time) for human exposure to sulphur dioxide is attempted for periods ranging from ten seconds to two hours. As an aid to assessment of the hazards involved in operating heavy water manufacturing facilities, the fact that sulphur dioxide would be produced by the combustion of hydrogen sulphide was briefly considered in an appendix. It is suggested that sulphuric acid, a much more toxic substance than sulphur dioxide, may also be formed in such an event. It is concluded, therefore, that an overall hazard evaluation may have to address the contributory effects of sulphuric acid. (author)

  14. Radiation Dose-Response Model for Locally Advanced Rectal Cancer After Preoperative Chemoradiation Therapy

    International Nuclear Information System (INIS)

    Appelt, Ane L.; Pløen, John; Vogelius, Ivan R.; Bentzen, Søren M.; Jakobsen, Anders

    2013-01-01

    Purpose: Preoperative chemoradiation therapy (CRT) is part of the standard treatment of locally advanced rectal cancers. Tumor regression at the time of operation is desirable, but not much is known about the relationship between radiation dose and tumor regression. In the present study we estimated radiation dose-response curves for various grades of tumor regression after preoperative CRT. Methods and Materials: A total of 222 patients, treated with consistent chemotherapy and radiation therapy techniques, were considered for the analysis. Radiation therapy consisted of a combination of external-beam radiation therapy and brachytherapy. Response at the time of operation was evaluated from the histopathologic specimen and graded on a 5-point scale (TRG1-5). The probability of achieving complete, major, and partial response was analyzed by ordinal logistic regression, and the effect of including clinical parameters in the model was examined. The radiation dose-response relationship for a specific grade of histopathologic tumor regression was parameterized in terms of the dose required for 50% response, D 50,i , and the normalized dose-response gradient, γ 50,i . Results: A highly significant dose-response relationship was found (P=.002). For complete response (TRG1), the dose-response parameters were D 50,TRG1 = 92.0 Gy (95% confidence interval [CI] 79.3-144.9 Gy), γ 50,TRG1 = 0.982 (CI 0.533-1.429), and for major response (TRG1-2) D 50,TRG1 and 2 = 72.1 Gy (CI 65.3-94.0 Gy), γ 50,TRG1 and 2 = 0.770 (CI 0.338-1.201). Tumor size and N category both had a significant effect on the dose-response relationships. Conclusions: This study demonstrated a significant dose-response relationship for tumor regression after preoperative CRT for locally advanced rectal cancer for tumor dose levels in the range of 50.4-70 Gy, which is higher than the dose range usually considered.

  15. A Unified Probabilistic Framework for Dose-Response Assessment of Human Health Effects.

    Science.gov (United States)

    Chiu, Weihsueh A; Slob, Wout

    2015-12-01

    When chemical health hazards have been identified, probabilistic dose-response assessment ("hazard characterization") quantifies uncertainty and/or variability in toxicity as a function of human exposure. Existing probabilistic approaches differ for different types of endpoints or modes-of-action, lacking a unifying framework. We developed a unified framework for probabilistic dose-response assessment. We established a framework based on four principles: a) individual and population dose responses are distinct; b) dose-response relationships for all (including quantal) endpoints can be recast as relating to an underlying continuous measure of response at the individual level; c) for effects relevant to humans, "effect metrics" can be specified to define "toxicologically equivalent" sizes for this underlying individual response; and d) dose-response assessment requires making adjustments and accounting for uncertainty and variability. We then derived a step-by-step probabilistic approach for dose-response assessment of animal toxicology data similar to how nonprobabilistic reference doses are derived, illustrating the approach with example non-cancer and cancer datasets. Probabilistically derived exposure limits are based on estimating a "target human dose" (HDMI), which requires risk management-informed choices for the magnitude (M) of individual effect being protected against, the remaining incidence (I) of individuals with effects ≥ M in the population, and the percent confidence. In the example datasets, probabilistically derived 90% confidence intervals for HDMI values span a 40- to 60-fold range, where I = 1% of the population experiences ≥ M = 1%-10% effect sizes. Although some implementation challenges remain, this unified probabilistic framework can provide substantially more complete and transparent characterization of chemical hazards and support better-informed risk management decisions.

  16. The Key Events Dose-Response Framework: a cross-disciplinary mode-of-action based approach to examining dose-response and thresholds.

    Science.gov (United States)

    Julien, Elizabeth; Boobis, Alan R; Olin, Stephen S

    2009-09-01

    The ILSI Research Foundation convened a cross-disciplinary working group to examine current approaches for assessing dose-response and identifying safe levels of intake or exposure for four categories of bioactive agents-food allergens, nutrients, pathogenic microorganisms, and environmental chemicals. This effort generated a common analytical framework-the Key Events Dose-Response Framework (KEDRF)-for systematically examining key events that occur between the initial dose of a bioactive agent and the effect of concern. Individual key events are considered with regard to factors that influence the dose-response relationship and factors that underlie variability in that relationship. This approach illuminates the connection between the processes occurring at the level of fundamental biology and the outcomes observed at the individual and population levels. Thus, it promotes an evidence-based approach for using mechanistic data to reduce reliance on default assumptions, to quantify variability, and to better characterize biological thresholds. This paper provides an overview of the KEDRF and introduces a series of four companion papers that illustrate initial application of the approach to a range of bioactive agents.

  17. Assembled cross-species perchlorate dose-response data

    Data.gov (United States)

    U.S. Environmental Protection Agency — This data set contains dose-response data for perchlorate exposure in multiple species. These data were assembled from peer-reviewed studies. Species included in...

  18. Mahalanobis distance and variable selection to optimize dose response

    International Nuclear Information System (INIS)

    Moore, D.H. II; Bennett, D.E.; Wyrobek, A.J.; Kranzler, D.

    1979-01-01

    A battery of statistical techniques are combined to improve detection of low-level dose response. First, Mahalanobis distances are used to classify objects as normal or abnormal. Then the proportion classified abnormal is regressed on dose. Finally, a subset of regressor variables is selected which maximizes the slope of the dose response line. Use of the techniques is illustrated by application to mouse sperm damaged by low doses of x-rays

  19. Positive biodiversity-productivity relationship predominant in global forests.

    Science.gov (United States)

    Liang, Jingjing; Crowther, Thomas W; Picard, Nicolas; Wiser, Susan; Zhou, Mo; Alberti, Giorgio; Schulze, Ernst-Detlef; McGuire, A David; Bozzato, Fabio; Pretzsch, Hans; de-Miguel, Sergio; Paquette, Alain; Hérault, Bruno; Scherer-Lorenzen, Michael; Barrett, Christopher B; Glick, Henry B; Hengeveld, Geerten M; Nabuurs, Gert-Jan; Pfautsch, Sebastian; Viana, Helder; Vibrans, Alexander C; Ammer, Christian; Schall, Peter; Verbyla, David; Tchebakova, Nadja; Fischer, Markus; Watson, James V; Chen, Han Y H; Lei, Xiangdong; Schelhaas, Mart-Jan; Lu, Huicui; Gianelle, Damiano; Parfenova, Elena I; Salas, Christian; Lee, Eungul; Lee, Boknam; Kim, Hyun Seok; Bruelheide, Helge; Coomes, David A; Piotto, Daniel; Sunderland, Terry; Schmid, Bernhard; Gourlet-Fleury, Sylvie; Sonké, Bonaventure; Tavani, Rebecca; Zhu, Jun; Brandl, Susanne; Vayreda, Jordi; Kitahara, Fumiaki; Searle, Eric B; Neldner, Victor J; Ngugi, Michael R; Baraloto, Christopher; Frizzera, Lorenzo; Bałazy, Radomir; Oleksyn, Jacek; Zawiła-Niedźwiecki, Tomasz; Bouriaud, Olivier; Bussotti, Filippo; Finér, Leena; Jaroszewicz, Bogdan; Jucker, Tommaso; Valladares, Fernando; Jagodzinski, Andrzej M; Peri, Pablo L; Gonmadje, Christelle; Marthy, William; O'Brien, Timothy; Martin, Emanuel H; Marshall, Andrew R; Rovero, Francesco; Bitariho, Robert; Niklaus, Pascal A; Alvarez-Loayza, Patricia; Chamuya, Nurdin; Valencia, Renato; Mortier, Frédéric; Wortel, Verginia; Engone-Obiang, Nestor L; Ferreira, Leandro V; Odeke, David E; Vasquez, Rodolfo M; Lewis, Simon L; Reich, Peter B

    2016-10-14

    The biodiversity-productivity relationship (BPR) is foundational to our understanding of the global extinction crisis and its impacts on ecosystem functioning. Understanding BPR is critical for the accurate valuation and effective conservation of biodiversity. Using ground-sourced data from 777,126 permanent plots, spanning 44 countries and most terrestrial biomes, we reveal a globally consistent positive concave-down BPR, showing that continued biodiversity loss would result in an accelerating decline in forest productivity worldwide. The value of biodiversity in maintaining commercial forest productivity alone-US$166 billion to 490 billion per year according to our estimation-is more than twice what it would cost to implement effective global conservation. This highlights the need for a worldwide reassessment of biodiversity values, forest management strategies, and conservation priorities. Copyright © 2016, American Association for the Advancement of Science.

  20. I-131 Dose Response for Incident Thyroid Cancers in Ukraine Related to the Chornobyl Accident

    OpenAIRE

    Brenner, Alina V.; Tronko, Mykola D.; Hatch, Maureen; Bogdanova, Tetyana I.; Oliynik, Valery A.; Lubin, Jay H.; Zablotska, Lydia B.; Tereschenko, Valery P.; McConnell, Robert J.; Zamotaeva, Galina A.; O?Kane, Patrick; Bouville, Andre C.; Chaykovskaya, Ludmila V.; Greenebaum, Ellen; Paster, Ihor P.

    2011-01-01

    Background: Current knowledge about Chornobyl-related thyroid cancer risks comes from ecological studies based on grouped doses, case?control studies, and studies of prevalent cancers. Objective: To address this limitation, we evaluated the dose?response relationship for incident thyroid cancers using measurement-based individual iodine-131 (I-131) thyroid dose estimates in a prospective analytic cohort study. Methods: The cohort consists of individuals < 18 years of age on 26 April 1986 who ...

  1. Theory of thermoluminescence gamma dose response: The unified interaction model

    International Nuclear Information System (INIS)

    Horowitz, Y.S.

    2001-01-01

    We describe the development of a comprehensive theory of thermoluminescence (TL) dose response, the unified interaction model (UNIM). The UNIM is based on both radiation absorption stage and recombination stage mechanisms and can describe dose response for heavy charged particles (in the framework of the extended track interaction model - ETIM) as well as for isotropically ionising gamma rays and electrons (in the framework of the TC/LC geminate recombination model) in a unified and self-consistent conceptual and mathematical formalism. A theory of optical absorption dose response is also incorporated in the UNIM to describe the radiation absorption stage. The UNIM is applied to the dose response supralinearity characteristics of LiF:Mg,Ti and is especially and uniquely successful in explaining the ionisation density dependence of the supralinearity of composite peak 5 in TLD-100. The UNIM is demonstrated to be capable of explaining either qualitatively or quantitatively all of the major features of TL dose response with many of the variable parameters of the model strongly constrained by ancilliary optical absorption and sensitisation measurements

  2. A Generalized QMRA Beta-Poisson Dose-Response Model.

    Science.gov (United States)

    Xie, Gang; Roiko, Anne; Stratton, Helen; Lemckert, Charles; Dunn, Peter K; Mengersen, Kerrie

    2016-10-01

    Quantitative microbial risk assessment (QMRA) is widely accepted for characterizing the microbial risks associated with food, water, and wastewater. Single-hit dose-response models are the most commonly used dose-response models in QMRA. Denoting PI(d) as the probability of infection at a given mean dose d, a three-parameter generalized QMRA beta-Poisson dose-response model, PI(d|α,β,r*), is proposed in which the minimum number of organisms required for causing infection, K min , is not fixed, but a random variable following a geometric distribution with parameter 0Poisson model, PI(d|α,β), is a special case of the generalized model with K min = 1 (which implies r*=1). The generalized beta-Poisson model is based on a conceptual model with greater detail in the dose-response mechanism. Since a maximum likelihood solution is not easily available, a likelihood-free approximate Bayesian computation (ABC) algorithm is employed for parameter estimation. By fitting the generalized model to four experimental data sets from the literature, this study reveals that the posterior median r* estimates produced fall short of meeting the required condition of r* = 1 for single-hit assumption. However, three out of four data sets fitted by the generalized models could not achieve an improvement in goodness of fit. These combined results imply that, at least in some cases, a single-hit assumption for characterizing the dose-response process may not be appropriate, but that the more complex models may be difficult to support especially if the sample size is small. The three-parameter generalized model provides a possibility to investigate the mechanism of a dose-response process in greater detail than is possible under a single-hit model. © 2016 Society for Risk Analysis.

  3. Dose response of tracheal epithelial cells to ionizing radiation in air-liquid interface cultures

    International Nuclear Information System (INIS)

    Fukutsu, K.; Yamada, Y.; Shimo, M.

    2002-01-01

    The dose-response relationships of tracheal epithelial cells to ionizing radiation was examined in air-liquid interface cultures, which were developed for the purpose of simulating in vivo conditions. The cultures investigated in this study were expected to be advantageous for the performance of irradiation experiments using short-range α rays. The level of dose response of air-liquid interface cultures to ionizing radiation proved to be the same as that for in vivo conditions. This result indicates that air-liquid interface cultures will prove most useful, to facilitate future studies for the investigation of the biological effects induced in tracheal epithelial cells by ionizing radiation, especially by α-rays. (orig.)

  4. Biological stress response terminology: Integrating the concepts of adaptive response and preconditioning stress within a hormetic dose-response framework

    International Nuclear Information System (INIS)

    Calabrese, Edward J.; Bachmann, Kenneth A.; Bailer, A. John; Bolger, P. Michael; Borak, Jonathan; Cai, Lu; Cedergreen, Nina; Cherian, M. George; Chiueh, Chuang C.; Clarkson, Thomas W.; Cook, Ralph R.; Diamond, David M.; Doolittle, David J.; Dorato, Michael A.; Duke, Stephen O.; Feinendegen, Ludwig; Gardner, Donald E.; Hart, Ronald W.; Hastings, Kenneth L.; Hayes, A. Wallace; Hoffmann, George R.; Ives, John A.; Jaworowski, Zbigniew; Johnson, Thomas E.; Jonas, Wayne B.; Kaminski, Norbert E.; Keller, John G.; Klaunig, James E.; Knudsen, Thomas B.; Kozumbo, Walter J.; Lettieri, Teresa; Liu, Shu-Zheng; Maisseu, Andre; Maynard, Kenneth I.; Masoro, Edward J.; McClellan, Roger O.; Mehendale, Harihara M.; Mothersill, Carmel; Newlin, David B.; Nigg, Herbert N.; Oehme, Frederick W.; Phalen, Robert F.; Philbert, Martin A.; Rattan, Suresh I.S.; Riviere, Jim E.; Rodricks, Joseph; Sapolsky, Robert M.; Scott, Bobby R.; Seymour, Colin; Sinclair, David A.; Smith-Sonneborn, Joan; Snow, Elizabeth T.; Spear, Linda; Stevenson, Donald E.; Thomas, Yolene; Tubiana, Maurice; Williams, Gary M.; Mattson, Mark P.

    2007-01-01

    Many biological subdisciplines that regularly assess dose-response relationships have identified an evolutionarily conserved process in which a low dose of a stressful stimulus activates an adaptive response that increases the resistance of the cell or organism to a moderate to severe level of stress. Due to a lack of frequent interaction among scientists in these many areas, there has emerged a broad range of terms that describe such dose-response relationships. This situation has become problematic because the different terms describe a family of similar biological responses (e.g., adaptive response, preconditioning, hormesis), adversely affecting interdisciplinary communication, and possibly even obscuring generalizable features and central biological concepts. With support from scientists in a broad range of disciplines, this article offers a set of recommendations we believe can achieve greater conceptual harmony in dose-response terminology, as well as better understanding and communication across the broad spectrum of biological disciplines

  5. Dose-response of photographic emulsions under gamma irradiation

    International Nuclear Information System (INIS)

    Tran Dai Nghiep; Do Thi Nguyet Minh; Le Van Vinh

    2003-01-01

    Photographic emulsion is irradiated under gamma rays irradiation of 137 Cs in the IAEA/WHO secondary standard dosimetry laboratory. Dose-response of the film is established. The sensitivity of the film is determined. The dose-rate effect is studied. (author)

  6. Dose-response relation between physical activity and sick leave

    NARCIS (Netherlands)

    Proper, K.I.; Heuvel, S.G. van den; Vroome, E.M. de; Hildebrandt, V.H.; Beek, A.J. van der

    2006-01-01

    Objective: To investigate the dose-response relation between moderate and vigorous physical activity and sick leave in a working population. Methods: Data were used from three large Dutch databases: two continuous, cross sectional surveys among a representative sample of the Dutch population and one

  7. Dose-response association between leisure time physical activity and work ability

    DEFF Research Database (Denmark)

    Calatayud, Joaquin; Jakobsen, Markus D.; Sundstrup, Emil

    2015-01-01

    INTRODUCTION: Regular physical activity is important for longevity and health, but knowledge about the optimal dose of physical activity for maintaining good work ability is unknown. This study investigates the association between intensity and duration of physical activity during leisure time......, lifestyle and chronic disease showed that the duration of high-intensity physical activity during leisure was positively associated with work ability, in a dose-response fashion (p physical activity per week had on average 8 points higher work ability...... than those not performing such activities. The duration of low-intensity leisure-time physical activity was not associated with work ability (p = 0.5668). CONCLUSIONS: The duration of high-intensity physical activity during leisure time is associated in a dose-response fashion with work ability...

  8. Human evidence on the shape of the dose-response curves for radiation carcinogenesis

    International Nuclear Information System (INIS)

    Burkart, W.

    1981-09-01

    The carcinogenic effects of high levels of ionizing radiation are better understood than those of any other environmental agent. However, the somatic risk from low doses is highly disputed. The uncertainties stem from the fact that a direct estimation of small risks requires impracticably large samples. Therefore, risk estimates for low doses have to be derived indirectly by extrapolation from high exposure data and are heavily dependent on assumptions about the form of the dose-response curve. Although radiobiological theories tested on in vitro systems predict a quadratic term in the dose-response equation which should, at least for sparsely ionizing radiation, dominate the shape of the curve, the epidemiological data available cannot exclude the possibility of a pure linear relationship. In some cases, apparent thresholds may result from latent periods inversely related to dose. Besides depending on the quality of the radiation, the shape seems also to differ with the type of cancer induced. Studies on uranium miners, atomic bomb survivors and on irradiated patients are reviewed with emphasis on the shape of the dose-response. The credibility of the most publicized reports claiming a large cancer risk from low levels of radiation is assessed. The feasibility of a new study in an area of high natural background is explored. Finally, the influence of the uncertainties concerning the effect of low level radiation on future exposure limits set by regulatory bodies is discussed. (Auth.)

  9. Dose-response model of Rocky Mountain spotted fever (RMSF) for human.

    Science.gov (United States)

    Tamrakar, Sushil B; Haas, Charles N

    2011-10-01

    Rickettsia rickettsii is the causative agent of Rocky Mountain spotted fever (RMSF) and is the prototype bacterium in the spotted fever group of rickettsiae, which is found in North, Central, and South America. The bacterium is gram negative and an obligate intracellular pathogen. The disease is transmitted to humans and vertebrate host through tick bites; however, some cases of aerosol transmission also have been reported. The disease can be difficult to diagnose in the early stages, and without prompt and appropriate treatment, it can be fatal. This article develops dose-response models of different routes of exposure for RMSF in primates and humans. The beta-Poisson model provided the best fit to the dose-response data of aerosol-exposed rhesus monkeys, and intradermally inoculated humans (morbidity as end point of response). The average 50% infectious dose among (ID₅₀) exposed human population, N₅₀, is 23 organisms with 95% confidence limits of 1 to 89 organisms. Similarly, ID₁₀ and ID₂₀ are 2.2 and 5.0, respectively. Moreover, the data of aerosol-exposed rhesus monkeys and intradermally inoculated humans could be pooled. This indicates that the dose-response models fitted to different data sets are not significantly different and can be described by the same relationship. © 2011 Society for Risk Analysis.

  10. Introduction to methodology of dose-response meta-analysis for binary outcome: With application on software.

    Science.gov (United States)

    Zhang, Chao; Jia, Pengli; Yu, Liu; Xu, Chang

    2018-05-01

    Dose-response meta-analysis (DRMA) is widely applied to investigate the dose-specific relationship between independent and dependent variables. Such methods have been in use for over 30 years and are increasingly employed in healthcare and clinical decision-making. In this article, we give an overview of the methodology used in DRMA. We summarize the commonly used regression model and the pooled method in DRMA. We also use an example to illustrate how to employ a DRMA by these methods. Five regression models, linear regression, piecewise regression, natural polynomial regression, fractional polynomial regression, and restricted cubic spline regression, were illustrated in this article to fit the dose-response relationship. And two types of pooling approaches, that is, one-stage approach and two-stage approach are illustrated to pool the dose-response relationship across studies. The example showed similar results among these models. Several dose-response meta-analysis methods can be used for investigating the relationship between exposure level and the risk of an outcome. However the methodology of DRMA still needs to be improved. © 2018 Chinese Cochrane Center, West China Hospital of Sichuan University and John Wiley & Sons Australia, Ltd.

  11. Pancreatic beta cell function increases in a linear dose-response manner following exercise training in adults with prediabetes

    DEFF Research Database (Denmark)

    Malin, Steven K; Solomon, Thomas; Blaszczak, Alecia

    2013-01-01

    While some studies suggest that a linear dose-response relationship exists between exercise and insulin sensitivity, the exercise dose required to enhance pancreatic beta-cell function is unknown. Thirty-five older, obese adults with prediabetes underwent a progressive 12-week supervised exercise...

  12. Investigation of J-shaped dose-responses induced by exposure to the alkylating agent N-methyl-N-nitrosourea.

    Science.gov (United States)

    Chapman, Katherine E; Hoffmann, George R; Doak, Shareen H; Jenkins, Gareth J S

    2017-07-01

    Hormesis is defined as a biphasic dose-response where biological effects of low doses of a stressor demonstrate the opposite effect to high-dose effects of the same stressor. Hormetic, or J-shaped, dose-response relationships are relatively rarely observed in toxicology, resulting in a limited understanding and even some skepticism of the concept. Low dose-response studies for genotoxicity endpoints have been performed at Swansea University for over a decade. However, no statistically significant decreases below control genotoxicity levels have been detected until recently. A hormetic-style dose-response following a 24h exposure to the alkylating agent N-methyl-N-nitrosourea (MNU) was observed in a previous study for HPRT mutagenesis in the human lymphoblastoid cell line AHH-1. A second recent study demonstrated a J-shaped dose-response for the induction of micronuclei by MNU in a 24h treatment in a similar test system. Following mechanistic investigations, it was hypothesized that p53 may be responsible for the observed hormetic phenomenon. As genotoxic carcinogens are a major causative factor of many cancers, consideration of hormesis in carcinogenesis could be important in safety assessment. The data examined here offer possible insights into hormesis, including its estimated prevalence, underlying mechanisms and lack of generalizability. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Radiation dose response of strand breaks in SINPV-DNA

    International Nuclear Information System (INIS)

    Zhang Chunxiang; Luo Daling; Li Mianfeng; Liu Xiaowei; Zeng Rong; Wang Xunzhang

    1995-01-01

    The Spodoplera litura Nuclear Polyhedrosis Viruses (SINPV) is a kind of insectile virus with a simple structure, in which a double helix DNA is encapsulated in a protein coat and there is no function of enzymatic repair. The SINPV samples in dry powdered form held in sealed plastic tube were irradiated by 1-100 kGy gamma rays. The single strand breaks (SSB) and double strand breaks (DSB) induced in SINPV after irradiation were measured by neutral and alkaline agarose gel electrophoresis. A dose-response function combining the responses of one-hit and two-hit events was used to describe the SSB and DSB dose-response curves. It is shown that the SSB are one-hit events and the DSB are the combination of both one-hit, and two-hit events, and two-hit events are predominant in the DSB process

  14. Leisure Activity Engagement and Positive Affect Partially Mediate the Relationship Between Positive Views on Aging and Physical Health.

    Science.gov (United States)

    Hicks, Stephanie A; Siedlecki, Karen L

    2017-03-01

    To examine leisure activity engagement and positive affect as potential mediators for the relationships between positive views on aging (PVA) and two health outcomes: subjective health and physical limitations. Data from 5,194 participants from the German Ageing Survey (aged 40-91 years) were used to examine relationships between PVA to subjective health (assessed by self-rated health and perceived health change from past) and physical limitations (assessed via self-reported limitations on 10 activities). Leisure activity engagement and positive affect were examined as potential mediators in latent variable path analyses. Age moderation among these relationships was also examined. Leisure activity engagement and positive affect separately and jointly served to partially mediate the relationships between PVA and the health outcomes. When entered as joint mediators, positive affect no longer significantly predicted physical limitations, indicating a shared variance with leisure activity engagement. Age moderated the relationship between PVA and physical limitations; the relationship was stronger among older adults than among middle-aged adults. Leisure activity engagement and positive affect were shown to help explain the relationship between PVA and health, but differently for different health constructs and also among middle-aged and older adults. Findings provide further insight into ways in which PVA influence health. © The Author 2016. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  15. Interpretation of the margin of exposure for genotoxic carcinogens - elicitation of expert knowledge about the form of the dose response curve at human relevant exposures.

    Science.gov (United States)

    Boobis, Alan; Flari, Villie; Gosling, John Paul; Hart, Andy; Craig, Peter; Rushton, Lesley; Idahosa-Taylor, Ehi

    2013-07-01

    The general approach to risk assessment of genotoxic carcinogens has been to advise reduction of exposure to "as low as reasonably achievable/practicable" (ALARA/P). However, whilst this remains the preferred risk management option, it does not provide guidance on the urgency or extent of risk management actions necessary. To address this, the "Margin of Exposure" (MOE) approach has been proposed. The MOE is the ratio between the point of departure for carcinogenesis and estimated human exposure. However, interpretation of the MOE requires implicit or explicit consideration of the shape of the dose-response curve at human relevant exposures. In a structured elicitation exercise, we captured expert opinion on available scientific evidence for low dose-response relationships for genotoxic carcinogens. This allowed assessment of: available evidence for the nature of dose-response relationships at human relevant exposures; the generality of judgments about such dose-response relationships; uncertainties affecting judgments on the nature of such dose-response relationships; and whether this last should differ for different classes of genotoxic carcinogens. Elicitation results reflected the variability in experts' views on the form of the dose-response curve for low dose exposure and major sources of uncertainty affecting the assumption of a linear relationship. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. Positive School Leadership: Building Capacity and Strengthening Relationships

    Science.gov (United States)

    Murphy, Joseph F.; Louis, Karen Seashore

    2018-01-01

    This landmark book translates positive and asset-based understandings of organizations to develop a powerful model of school leadership that is grounded in both existing research and the complexities of life in schools. The authors--both senior scholars in educational leadership--apply insights from positive psychology to the role and function of…

  17. Treatment dose-response in amblyopia therapy: the Monitored Occlusion Treatment of Amblyopia Study (MOTAS).

    Science.gov (United States)

    Stewart, Catherine E; Moseley, Merrick J; Stephens, David A; Fielder, Alistair R

    2004-09-01

    Amblyopia is the commonest visual disorder of childhood. Yet the contributions of the two principal treatments (spectacle wear and occlusion) to outcome are unknown. This study was undertaken to investigate the dose-response relationship of amblyopia therapy. The study comprised three distinct phases: baseline, in which repeat measures of visual function were undertaken to confirm the initial visual deficit; refractive adaptation: an 18-week period of spectacle wear with six weekly measurements of logarithm of the minimum angle of resolution (logMAR) visual acuity; occlusion: in which participants were prescribed 6 hours of "patching" per day. In the latter phase, occlusion was objectively monitored and logMAR visual acuity recorded at 2-week intervals until any observed gains had ceased. Data were obtained from 94 participants (mean age, 5.1 +/- 1.4 years) with amblyopia associated with strabismus (n = 34), anisometropia (n = 23), and both anisometropia and strabismus (n = 37). Eighty-six underwent refractive adaptation. Average concordance with patching was 48%. The relationship between logMAR visual acuity gain and total occlusion dose was monotonic and linear. Increasing dose rate beyond 2 h/d hastened the response but did not improve outcome. More than 80% of the improvement during occlusion occurred within 6 weeks. Treatment outcome was significantly better for children younger than 4 years (n = 17) than in those older than 6 years (n = 24; P = 0.0014). Continuous objective monitoring of the amount of patching therapy received has provided insight into the dose-response relationship of occlusion therapy for amblyopia. Patching is most effective within the first few weeks of treatment, even for those in receipt of a relatively small dose. Further studies are needed to elucidate the neural basis for the dose-response functions. Copyright Association for Research in Vision and Ophthalmology

  18. Hormesis: from marginalization to mainstream A case for hormesis as the default dose-response model in risk assessment

    International Nuclear Information System (INIS)

    Calabrese, Edward J.

    2004-01-01

    The paper provides an account of how the hormetic dose response has emerged in recent years as a serious dose-response model in toxicology and risk assessment after decades of extreme marginalization. In addition to providing the toxicological basis of this dose-response revival, the paper reexamines the concept of a default dose model in toxicology and risk assessment and makes the argument that the hormetic model satisfies criteria (e.g., generalizability, frequency, application to risk assessment endpoints, false positive/negative potential, requirements for hazard assessment, reliability of estimating risks, capacity for validation of risk estimates, public health implications of risk estimates) for such a default model better than its chief competitors, the threshold and linear at low dose models. The selection of the hormetic model as the default model in risk assessment for noncarcinogens and specifically for carcinogens would have a profound impact on the practice of risk assessment and its societal implications

  19. Bringing Boys and Girls Together: Supporting Preschoolers' Positive Peer Relationships

    Science.gov (United States)

    Manaster, Hillary; Jobe, Maureen

    2012-01-01

    Children thrive in inclusive settings where each child is an important part of the community. When differences are celebrated and similarities discovered, children learn to value themselves, appreciate their peers, and develop meaningful and significant relationships with one another. A sizable body of research indicates that promoting positive…

  20. Relationships Among Positive Emotions, Coping, Resilience and Mental Health.

    Science.gov (United States)

    Gloria, Christian T; Steinhardt, Mary A

    2016-04-01

    The broaden-and-build theory of positive emotions suggests that positive emotions can widen the range of potential coping strategies that come to mind and subsequently enhance one's resilience against stress. Studies have shown that high stress, especially chronic levels of stress, strongly contributes to the development of anxiety and depressive symptoms. However, researchers have also found that individuals who possess high levels of resilience are protected from stress and thus report lower levels of anxiety and depressive symptoms. Using a sample of 200 postdoctoral research fellows, the present study examined if (a) positive emotions were associated with greater resilience, (b) coping strategies mediated the link between positive emotions and resilience and (c) resilience moderated the influence of stress on trait anxiety and depressive symptoms. Results support the broaden-and-build theory in that positive emotions may enhance resilience directly as well as indirectly through the mediating role of coping strategies-particularly via adaptive coping. Resilience also moderated the association of stress with trait anxiety and depressive symptoms. Although stress is unavoidable and its influences on anxiety and depressive symptoms are undeniable, the likelihood of postdocs developing anxiety or depressive symptoms may be reduced by implementing programmes designed to increase positive emotions, adaptive coping strategies and resilience. Copyright © 2014 John Wiley & Sons, Ltd.

  1. Dose-response model of murine typhus (Rickettsia typhi: time post inoculation and host age dependency analysis

    Directory of Open Access Journals (Sweden)

    Tamrakar Sushil B

    2012-03-01

    Full Text Available Abstract Background Rickettsia typhi (R. mooseri is the causative agent of murine typhus. It is one of the most widely distributed flea-borne diseases with a relatively mild febrile initial illness with six to 14 days of incubation period. The bacterium is gram negative and an obligate intracellular pathogen. The disease is transmitted to humans and vertebrate host through fleabites or via contact with infected feces. This paper develops dose-response models of different routes of exposure for typhus in rodents. Methods Data from published articles were analyzed using parametric dose-response relationship models. Dose-response relationships were fit to data using the method of maximum likelihood estimation (MLE. Results Dose-response models quantifying the effects of different ages of rats and time post inoculation in BALB/c mice were analyzed in the study. Both the adult rats (inoculated intradermally and newborn rats (inoculated subcutaneously were best fit by exponential models and both distributions could be described by a single dose-response relationship. The BALB/C mice inoculated subcutaneously were best fit by Beta-Poisson models. The time post inoculation analysis showed that there was a definite time and response relationship existed in this case. Conclusions Intradermally or subcutaneously inoculated rats (adult and newborn models suggest that less than 1 plaque-forming unit (PFU (1.33 to 0.38 in 95% confidence limits of the pathogen is enough to seroconvert 50% of the exposed population on average. For the BALB/c mouse time post inoculation model, an average dose of 0.28 plaque-forming units (PFU (0.75 to 0.11 in 95% confidence limits will seroconvert 50% of the exposed mice.

  2. Obesity and the relationship with positive and negative affect.

    Science.gov (United States)

    Pasco, Julie A; Williams, Lana J; Jacka, Felice N; Brennan, Sharon L; Berk, Michael

    2013-05-01

    To examine the cross-sectional association between overweight and obesity and positive and negative affect. Participants included 273 women, aged 29-84 years, who were enrolled in the Geelong Osteoporosis Study (GOS). Weight and height were measured and overweight and obesity determined from body mass index (BMI; kg/m(2)) according to WHO criteria. Medical history and lifestyle exposures were assessed by questionnaire. Positive and negative affect scores were derived using the validated 20-item Positive and Negative Affect Schedule (PANAS) and categorised into tertiles. A pattern of greater negative affect scores was observed for increasing levels of BMI. Setting normal weight as the referent category, the odds for having a negative affect score in the highest tertile were sequentially increased for women who were overweight (OR = 1.31, 95% CI: 0.72-2.40) and obese (OR = 1.95, 95% CI: 1.02-3.73). The association between obesity and increased negative affect was diminished by adjusting for physical illness (adjusted OR = 1.76, 95% CI: 0.91-3.42). These associations were not substantially influenced by positive affect score or other exposures. No association was detected between BMI categories and positive affect scores. We report data suggesting that obesity is associated with greater negative affect scores, reflecting emotions such as distress, anger, disgust, fear and shame, and that this association is attenuated by physical illness. Further investigations are now warranted to explore possible mechanistic interplay between pathological, neurobiological and psychosocial factors.

  3. Biological dosimetry in radiation accidents. Dose-response curve by chromosomal aberrations analysis

    International Nuclear Information System (INIS)

    Hadjidekova, V.; Hristova, R.; Atanasova, P.; Popova, L.; Stainova, A.; Bulanova, M.; Georgieva, I.; Vukov, M.

    2005-01-01

    The aim of this paper is to obtain a dose-response relationship for chromosomal aberrations induced in human lymphocytes after in vitro irradiation. Peripheral blood samples of 7 different donors were used. The blood irradiation was done with Cs137 gamma-rays at different doses: 0.0, 0.05, 0.1, 0.25, 0.5, 0.75, 1.0, 1.5, 2.0 and 3.0 Gy. Lymphocyte cultures were established and maintain for 48 hours at 37 0 C in CO 2 incubator for chromosomal aberration analysis. The dose response relationship has been established based on dysenteric and ring chromosomes yield. The relationship can be described by the following equation: Y = 0.0274D + 0.0251 D 2 , where (Y) = dysenteric and ring chromosomes yield, (D) = radiation dose obtained. EXCEL software was established for calculation of the received dose by using this equation, as a whole body equivalent dose acute irradiation

  4. Paradigm lost, paradigm found: The re-emergence of hormesis as a fundamental dose response model in the toxicological sciences

    Energy Technology Data Exchange (ETDEWEB)

    Calabrese, Edward J. [Environmental Health Sciences, School of Public Health, Morrill I, N344, University of Massachusetts, Amherst, MA 01003 (United States)]. E-mail: edwardc@schoolph.umass.edu

    2005-12-15

    This paper provides an assessment of the toxicological basis of the hormetic dose-response relationship including issues relating to its reproducibility, frequency, and generalizability across biological models, endpoints measured and chemical class/physical stressors and implications for risk assessment. The quantitative features of the hormetic dose response are described and placed within toxicological context that considers study design, temporal assessment, mechanism, and experimental model/population heterogeneity. Particular emphasis is placed on an historical evaluation of why the field of toxicology rejected hormesis in favor of dose response models such as the threshold model for assessing non-carcinogens and linear no threshold (LNT) models for assessing carcinogens. The paper argues that such decisions were principally based on complex historical factors that emerged from the intense and protracted conflict between what is now called traditional medicine and homeopathy and the overly dominating influence of regulatory agencies on the toxicological intellectual agenda. Such regulatory agency influence emphasized hazard/risk assessment goals such as the derivation of no observed adverse effect levels (NOAELs) and the lowest observed adverse effect levels (LOAELs) which were derived principally from high dose studies using few doses, a feature which restricted perceptions and distorted judgments of several generations of toxicologists concerning the nature of the dose-response continuum. Such historical and technical blind spots lead the field of toxicology to not only reject an established dose-response model (hormesis), but also the model that was more common and fundamental than those that the field accepted. - The quantitative features of the hormetic dose/response are described and placed within the context of toxicology.

  5. Paradigm lost, paradigm found: The re-emergence of hormesis as a fundamental dose response model in the toxicological sciences

    International Nuclear Information System (INIS)

    Calabrese, Edward J.

    2005-01-01

    This paper provides an assessment of the toxicological basis of the hormetic dose-response relationship including issues relating to its reproducibility, frequency, and generalizability across biological models, endpoints measured and chemical class/physical stressors and implications for risk assessment. The quantitative features of the hormetic dose response are described and placed within toxicological context that considers study design, temporal assessment, mechanism, and experimental model/population heterogeneity. Particular emphasis is placed on an historical evaluation of why the field of toxicology rejected hormesis in favor of dose response models such as the threshold model for assessing non-carcinogens and linear no threshold (LNT) models for assessing carcinogens. The paper argues that such decisions were principally based on complex historical factors that emerged from the intense and protracted conflict between what is now called traditional medicine and homeopathy and the overly dominating influence of regulatory agencies on the toxicological intellectual agenda. Such regulatory agency influence emphasized hazard/risk assessment goals such as the derivation of no observed adverse effect levels (NOAELs) and the lowest observed adverse effect levels (LOAELs) which were derived principally from high dose studies using few doses, a feature which restricted perceptions and distorted judgments of several generations of toxicologists concerning the nature of the dose-response continuum. Such historical and technical blind spots lead the field of toxicology to not only reject an established dose-response model (hormesis), but also the model that was more common and fundamental than those that the field accepted. - The quantitative features of the hormetic dose/response are described and placed within the context of toxicology

  6. Fractional poisson--a simple dose-response model for human norovirus.

    Science.gov (United States)

    Messner, Michael J; Berger, Philip; Nappier, Sharon P

    2014-10-01

    This study utilizes old and new Norovirus (NoV) human challenge data to model the dose-response relationship for human NoV infection. The combined data set is used to update estimates from a previously published beta-Poisson dose-response model that includes parameters for virus aggregation and for a beta-distribution that describes variable susceptibility among hosts. The quality of the beta-Poisson model is examined and a simpler model is proposed. The new model (fractional Poisson) characterizes hosts as either perfectly susceptible or perfectly immune, requiring a single parameter (the fraction of perfectly susceptible hosts) in place of the two-parameter beta-distribution. A second parameter is included to account for virus aggregation in the same fashion as it is added to the beta-Poisson model. Infection probability is simply the product of the probability of nonzero exposure (at least one virus or aggregate is ingested) and the fraction of susceptible hosts. The model is computationally simple and appears to be well suited to the data from the NoV human challenge studies. The model's deviance is similar to that of the beta-Poisson, but with one parameter, rather than two. As a result, the Akaike information criterion favors the fractional Poisson over the beta-Poisson model. At low, environmentally relevant exposure levels (Poisson model; however, caution is advised because no subjects were challenged at such a low dose. New low-dose data would be of great value to further clarify the NoV dose-response relationship and to support improved risk assessment for environmentally relevant exposures. © 2014 Society for Risk Analysis Published 2014. This article is a U.S. Government work and is in the public domain for the U.S.A.

  7. Low-Active Male Adolescents: A Dose Response to High-Intensity Interval Training.

    Science.gov (United States)

    Logan, Greig Robert Melrose; Harris, Nigel; Duncan, Scott; Plank, Lindsay D; Merien, Fabrice; Schofield, Grant

    2016-03-01

    High-intensity interval training (HIIT) is a potential alternative to traditionally recommended steady state exercise for providing health benefits in adolescents, yet its dose-response relationship in this cohort remains unclear, as does its translatability to real-world, nonclinical settings. The present study adopts a novel dose-response design to investigate the effects of undertaking 8 wk of HIIT on the cardiometabolic health of low-active male adolescents. Twenty-six male adolescents (age 16 ± 1 yr), identified as low active by nonparticipation in structured sport and physical education classes, were randomly assigned to one of five treatment groups. Corresponding with their group numbers (1-5), participants completed a number of HIIT "sets," which consisted of 4 repeated bouts of 20-s near-maximal exertion interspersed with 10-s passive recovery. Participants performed two HIIT sessions and one resistance training session each week for 8 wk. Baseline and follow-up health measures consisted of peak oxygen uptake (V˙O2peak) with an incremental ramp test to volitional exhaustion; body composition (including visceral fat mass, body fat, and lean tissue mass) with dual-energy x-ray absorptiometry; and lipid profile, glucose, insulin, and interleukin-6 from blood analysis. All health outcomes were analyzed as percentage changes, and data were modeled using a quadratic function to explore dose-response relationships. Significant improvements were observed for V˙O2peak (∼6%), body fat percentage (∼4%), visceral fat mass (∼10%), and waist circumference-to-height ratio (∼3%), but there was no clear effect of dose across groups. Low-active adolescent males performing a single HIIT set twice weekly, in addition to one resistance training session, gained meaningful improvements in fitness and body composition. Performing additional HIIT sets provided no additional improvements to those of the lowest dose in this study.

  8. The Radiation Dose-Response of the Human Spinal Cord

    International Nuclear Information System (INIS)

    Schultheiss, Timothy E.

    2008-01-01

    Purpose: To characterize the radiation dose-response of the human spinal cord. Methods and Materials: Because no single institution has sufficient data to establish a dose-response function for the human spinal cord, published reports were combined. Requisite data were dose and fractionation, number of patients at risk, number of myelopathy cases, and survival experience of the population. Eight data points for cervical myelopathy were obtained from five reports. Using maximum likelihood estimation correcting for the survival experience of the population, estimates were obtained for the median tolerance dose, slope parameter, and α/β ratio in a logistic dose-response function. An adequate fit to thoracic data was not possible. Hyperbaric oxygen treatments involving the cervical cord were also analyzed. Results: The estimate of the median tolerance dose (cervical cord) was 69.4 Gy (95% confidence interval, 66.4-72.6). The α/β = 0.87 Gy. At 45 Gy, the (extrapolated) probability of myelopathy is 0.03%; and at 50 Gy, 0.2%. The dose for a 5% myelopathy rate is 59.3 Gy. Graphical analysis indicates that the sensitivity of the thoracic cord is less than that of the cervical cord. There appears to be a sensitizing effect from hyperbaric oxygen treatment. Conclusions: The estimate of α/β is smaller than usually quoted, but values this small were found in some studies. Using α/β = 0.87 Gy, one would expect a considerable advantage by decreasing the dose/fraction to less than 2 Gy. These results were obtained from only single fractions/day and should not be applied uncritically to hyperfractionation

  9. Dose Response of Alanine Detectors Irradiated with Carbon Ion Beams

    DEFF Research Database (Denmark)

    Herrmann, Rochus; Jäkel, Oliver; Palmans, Hugo

    2011-01-01

    Purpose: The dose response of the alanine detector shows a dependence on particle energy and type, when irradiated with ion beams. The purpose of this study is to investigate the response behaviour of the alanine detector in clinical carbon ion beams and compare the results with model predictions......-dose curves deviate from predictions in the peak region, most pronounced at the distal edge of the peak. Conclusions: The used model and its implementation show a good overall agreement for quasi mono energetic measurements. Deviations in depth-dose measurements are mainly attributed to uncertainties...

  10. Cognitive Engagement Mediates the Relationship between Positive Life Events and Positive Emotionality

    Directory of Open Access Journals (Sweden)

    Alexander Strobel

    2017-10-01

    Full Text Available Need for Cognition (NFC is conceptualized as an individuals’ tendency to engage in and enjoy effortful cognitive activity and, thus, captures one’s cognitive engagement. It plays a well-established role in information processing in experimental or academic contexts. However, so far comparably little is known about its consequences for other than purely cognitive or academic outcomes. Indeed, NFC is positively associated with personality traits pertaining to Positive Emotionality (PE and negatively to traits related to Negative Emotionality (NE. Moreover, evidence suggests NFC to be related to an active, problem-focused coping style. We therefore hypothesized NFC to mediate between life events and individual differences in PE and NE. In a sample of N = 202 volunteers from the general population, we observed that the number of past positive and negative life events had direct effects on PE, and NE, respectively, and that for positive life events, a mediating effect on PE via NFC was observed, with a higher number of past positive life events being related to higher NFC that in turn was related to increased PE. Thus, the present results lend support to the notion of NFC as an important factor supporting personal well-being by way of its mediating role between the number of past positive life events and positive affect.

  11. Maximum likelihood estimation for cytogenetic dose-response curves

    International Nuclear Information System (INIS)

    Frome, E.L; DuFrain, R.J.

    1983-10-01

    In vitro dose-response curves are used to describe the relation between the yield of dicentric chromosome aberrations and radiation dose for human lymphocytes. The dicentric yields follow the Poisson distribution, and the expected yield depends on both the magnitude and the temporal distribution of the dose for low LET radiation. A general dose-response model that describes this relation has been obtained by Kellerer and Rossi using the theory of dual radiation action. The yield of elementary lesions is kappa[γd + g(t, tau)d 2 ], where t is the time and d is dose. The coefficient of the d 2 term is determined by the recovery function and the temporal mode of irradiation. Two special cases of practical interest are split-dose and continuous exposure experiments, and the resulting models are intrinsically nonlinear in the parameters. A general purpose maximum likelihood estimation procedure is described and illustrated with numerical examples from both experimental designs. Poisson regression analysis is used for estimation, hypothesis testing, and regression diagnostics. Results are discussed in the context of exposure assessment procedures for both acute and chronic human radiation exposure

  12. Maximum likelihood estimation for cytogenetic dose-response curves

    International Nuclear Information System (INIS)

    Frome, E.L.; DuFrain, R.J.

    1986-01-01

    In vitro dose-response curves are used to describe the relation between chromosome aberrations and radiation dose for human lymphocytes. The lymphocytes are exposed to low-LET radiation, and the resulting dicentric chromosome aberrations follow the Poisson distribution. The expected yield depends on both the magnitude and the temporal distribution of the dose. A general dose-response model that describes this relation has been presented by Kellerer and Rossi (1972, Current Topics on Radiation Research Quarterly 8, 85-158; 1978, Radiation Research 75, 471-488) using the theory of dual radiation action. Two special cases of practical interest are split-dose and continuous exposure experiments, and the resulting dose-time-response models are intrinsically nonlinear in the parameters. A general-purpose maximum likelihood estimation procedure is described, and estimation for the nonlinear models is illustrated with numerical examples from both experimental designs. Poisson regression analysis is used for estimation, hypothesis testing, and regression diagnostics. Results are discussed in the context of exposure assessment procedures for both acute and chronic human radiation exposure

  13. Maximum likelihood estimation for cytogenetic dose-response curves

    Energy Technology Data Exchange (ETDEWEB)

    Frome, E.L; DuFrain, R.J.

    1983-10-01

    In vitro dose-response curves are used to describe the relation between the yield of dicentric chromosome aberrations and radiation dose for human lymphocytes. The dicentric yields follow the Poisson distribution, and the expected yield depends on both the magnitude and the temporal distribution of the dose for low LET radiation. A general dose-response model that describes this relation has been obtained by Kellerer and Rossi using the theory of dual radiation action. The yield of elementary lesions is kappa(..gamma..d + g(t, tau)d/sup 2/), where t is the time and d is dose. The coefficient of the d/sup 2/ term is determined by the recovery function and the temporal mode of irradiation. Two special cases of practical interest are split-dose and continuous exposure experiments, and the resulting models are intrinsically nonlinear in the parameters. A general purpose maximum likelihood estimation procedure is described and illustrated with numerical examples from both experimental designs. Poisson regression analysis is used for estimation, hypothesis testing, and regression diagnostics. Results are discussed in the context of exposure assessment procedures for both acute and chronic human radiation exposure.

  14. The dose-response analysis between BMI and common chronic diseases in northeast China.

    Science.gov (United States)

    Yu, Jianxing; Tao, Yuchun; Dou, Jing; Ye, Junsen; Yu, Yaqin; Jin, Lina

    2018-03-09

    High body mass index (BMI) predisposes to several chronic diseases, but a large-scale systematic and detailed study of dose-response relationship between BMI and chronic diseases has not been reported previously. In this study, we aimed to investigate the relationship between BMI and 3 chronic diseases (hypertension, dyslipidemia and MetS) in northeast China. A sample of 16412 participants aged 18~79 years old were included in Jilin province in 2012. The lambda-mu-sigma (LMS) method was applied to examine the trend of BMI by age, and the restricted cubic splines were used to investigate the non-linear associations (dose-response curve) between BMI and chronic diseases. It was pointed out that BMI increased rapidly when young, then kept steady in middle age, and finally declined slowly in old age, and accordingly age was divided into 3 segments, which were different by gender. The odds ratios (ORs) of BMI for the chronic diseases increased relatively slowly when young, then increased dramatically in middle-age and old population, especially for men. Further, the ORs of BMI among non-smokers were lower than those among smokers, and the same trend was shown to be more apparent among drinkers and non-drinkers. The risk of BMI for common chronic diseases increased dramatically in middle-aged, especially for men with drinking and smoking habits.

  15. I-131 dose response for incident thyroid cancers in Ukraine related to the Chornobyl accident.

    Science.gov (United States)

    Brenner, Alina V; Tronko, Mykola D; Hatch, Maureen; Bogdanova, Tetyana I; Oliynik, Valery A; Lubin, Jay H; Zablotska, Lydia B; Tereschenko, Valery P; McConnell, Robert J; Zamotaeva, Galina A; O'Kane, Patrick; Bouville, Andre C; Chaykovskaya, Ludmila V; Greenebaum, Ellen; Paster, Ihor P; Shpak, Victor M; Ron, Elaine

    2011-07-01

    Current knowledge about Chornobyl-related thyroid cancer risks comes from ecological studies based on grouped doses, case-control studies, and studies of prevalent cancers. To address this limitation, we evaluated the dose-response relationship for incident thyroid cancers using measurement-based individual iodine-131 (I-131) thyroid dose estimates in a prospective analytic cohort study. The cohort consists of individuals radioactivity measurements taken within 2 months after the accident, environmental transport models, and interview data. Excess radiation risks were estimated using Poisson regression models. Sixty-five incident thyroid cancers were diagnosed during the second through fourth screenings and 73,004 person-years (PY) of observation. The dose-response relationship was consistent with linearity on relative and absolute scales, although the excess relative risk (ERR) model described data better than did the excess absolute risk (EAR) model. The ERR per gray was 1.91 [95% confidence interval (CI), 0.43-6.34], and the EAR per 10⁴ PY/Gy was 2.21 (95% CI, 0.04-5.78). The ERR per gray varied significantly by oblast of residence but not by time since exposure, use of iodine prophylaxis, iodine status, sex, age, or tumor size. I-131-related thyroid cancer risks persisted for two decades after exposure, with no evidence of decrease during the observation period. The radiation risks, although smaller, are compatible with those of retrospective and ecological post-Chornobyl studies.

  16. Heavy particle irradiation, neurochemistry and behavior: thresholds, dose-response curves and recovery of function

    Science.gov (United States)

    Rabin, B. M.; Joseph, J. A.; Shukitt-Hale, B.

    2004-01-01

    Exposure to heavy particles can affect the functioning of the central nervous system (CNS), particularly the dopaminergic system. In turn, the radiation-induced disruption of dopaminergic function affects a variety of behaviors that are dependent upon the integrity of this system, including motor behavior (upper body strength), amphetamine (dopamine)-mediated taste aversion learning, and operant conditioning (fixed-ratio bar pressing). Although the relationships between heavy particle irradiation and the effects of exposure depend, to some extent, upon the specific behavioral or neurochemical endpoint under consideration, a review of the available research leads to the hypothesis that the endpoints mediated by the CNS have certain characteristics in common. These include: (1) a threshold, below which there is no apparent effect; (2) the lack of a dose-response relationship, or an extremely steep dose-response curve, depending on the particular endpoint; and (3) the absence of recovery of function, such that the heavy particle-induced behavioral and neural changes are present when tested up to one year following exposure. The current report reviews the data relevant to the degree to which these characteristics are common to neurochemical and behavioral endpoints that are mediated by the effects of exposure to heavy particles on CNS activity.

  17. Discordant relationship between Essure microinsert position and tubal occlusion.

    Science.gov (United States)

    Hou, Melody Y

    2016-07-27

    Hysteroscopic sterilisation with Essure requires confirmation of tubal occlusion by hysterosalpingogram or microinsert position by transvaginal sonography 3 months after placement before women can rely on the method for pregnancy prevention. A 39-year-old woman underwent hysteroscopic sterilisation via Essure, with successful bilateral tubal occlusion documented on hysterosalpingogram. She had a subsequent unintended pregnancy and termination, and presented with persistent pelvic pain and other non-specific symptoms. She underwent a laparoscopic-assisted vaginal hysterectomy with bilateral salpingectomy, with complete resolution of her symptoms. Pathological evaluation demonstrated a perforated Essure microinsert and ipsilateral tubal occlusion, and a correctly placed Essure microinsert with ipsilateral tubal patency. Clinicians should be cautious about the assumption that correctly placed microinserts based on ultrasonography, hysterosalpingogram or laparoscopic evaluation assures occlusion success. 2016 BMJ Publishing Group Ltd.

  18. External beam radiotherapy for painful osseous metastases: pooled data dose response analysis

    International Nuclear Information System (INIS)

    Ben-Josef, Edgar; Shamsa, Falah; Youssef, Emad; Porter, Arthur T.

    1999-01-01

    Purpose: Although the effectiveness of external beam irradiation in palliation of pain from osseous metastases is well established, the optimal fractionation schedule has not been determined. Clinical studies to date have failed to demonstrate an advantage for higher doses. To further address this issue, we conducted a pooled dose response analysis using data from published Phase III clinical trials. Methods and Materials: Complete response (CR) was used as an endpoint because it was felt to be least susceptible to inconsistencies in assessment.The biological effective dose (BED) was calculated for each schedule using the linear-quadratic model and an α/β of 10. Using SAS version 6.12, the data were fitted using a weighted linear regression, a logistic model, and the spline technique. Finally, BED was categorized, and odds ratios for each level were calculated. Results: CR was assessed early and late in 383 and 1,007 patients, respectively. Linear regression on the early-response data yielded a poor fit and a nonsignificant dose coefficient. With the late-response data, there was an excellent fit (R-square = 0.842) and a highly significant dose coefficient (p = 0.0002). Fitting early CR to a logistic model, we could not establish a significant dose response relationship. However, with the late-response data there was an excellent fit and the dose coefficient was significantly different from zero (0.017 ± 0.00524; p = 0.0012). Application of the spline technique or removal of an outlier resulted in an improved fit (p 0.048 and p = 0.0001, respectively). Using BED of < 14.4 Gy as a reference level, the odds ratios for late CR were 2.29-3.32 (BED of 19.5-51.4 Gy, respectively). Conclusion: Our results demonstrate a clear dose-response for pain relief. Further testing of high intensity regiments is warranted

  19. Nonlinear mixed effects dose response modeling in high throughput drug screens: application to melanoma cell line analysis.

    Science.gov (United States)

    Ding, Kuan-Fu; Petricoin, Emanuel F; Finlay, Darren; Yin, Hongwei; Hendricks, William P D; Sereduk, Chris; Kiefer, Jeffrey; Sekulic, Aleksandar; LoRusso, Patricia M; Vuori, Kristiina; Trent, Jeffrey M; Schork, Nicholas J

    2018-01-12

    Cancer cell lines are often used in high throughput drug screens (HTS) to explore the relationship between cell line characteristics and responsiveness to different therapies. Many current analysis methods infer relationships by focusing on one aspect of cell line drug-specific dose-response curves (DRCs), the concentration causing 50% inhibition of a phenotypic endpoint (IC 50 ). Such methods may overlook DRC features and do not simultaneously leverage information about drug response patterns across cell lines, potentially increasing false positive and negative rates in drug response associations. We consider the application of two methods, each rooted in nonlinear mixed effects (NLME) models, that test the relationship relationships between estimated cell line DRCs and factors that might mitigate response. Both methods leverage estimation and testing techniques that consider the simultaneous analysis of different cell lines to draw inferences about any one cell line. One of the methods is designed to provide an omnibus test of the differences between cell line DRCs that is not focused on any one aspect of the DRC (such as the IC 50 value). We simulated different settings and compared the different methods on the simulated data. We also compared the proposed methods against traditional IC 50 -based methods using 40 melanoma cell lines whose transcriptomes, proteomes, and, importantly, BRAF and related mutation profiles were available. Ultimately, we find that the NLME-based methods are more robust, powerful and, for the omnibus test, more flexible, than traditional methods. Their application to the melanoma cell lines reveals insights into factors that may be clinically useful.

  20. Proposal of a probabilistic dose-response model

    International Nuclear Information System (INIS)

    Barrachina, M.

    1997-01-01

    A biologically updated dose-response model is presented as an alternative to the linear-quadratic model currently in use for cancer risk assessment. The new model is based on the probability functions for misrepair and/or unrepair of DNA lesions, in terms of the radiation damage production rate in the cell (supposedly, a stem cell) and its repair-rate constant. The model makes use, interpreting it on the basis of misrepair probabilities, of the ''dose and dose-rate effectiveness factor'' of ICRP, and provides the way for a continuous extrapolation between the high and low dose-rate regions, ratifying the ''linear non-threshold hypothesis'' as the main option. Anyhow, the model throws some doubts about the additive property of the dose. (author)

  1. Repair and dose-response at low doses

    International Nuclear Information System (INIS)

    Totter, J.R.; Weinberg, A.M.

    1977-04-01

    The DNA of each individual is subject to formation of some 2-4 x 10 14 ion pairs during the first 30 years of life from background radiation. If a single hit is sufficient to cause cancer, as is implicit in the linear, no-threshold theories, it is unclear why all individuals do not succumb to cancer, unless repair mechanisms operate to remove the damage. We describe a simple model in which the exposed population displays a distribution of repair thresholds. The dose-response at low dose is shown to depend on the shape of the threshold distribution at low thresholds. If the probability of zero threshold is zero, the response at low dose is quadratic. The model is used to resolve a longstanding discrepancy between observed incidence of leukemia at Nagasaki and the predictions of the usual linear hypothesis

  2. Alcohol and cirrhosis: dose--response or threshold effect?

    DEFF Research Database (Denmark)

    Kamper-Jørgensen, Mads; Grønbaek, Morten; Tolstrup, Janne

    2004-01-01

    BACKGROUND/AIMS: General population studies have shown a strong association between alcohol intake and death from alcoholic cirrhosis, but whether this is a dose-response or a threshold effect remains unknown, and the relation among alcohol misusers has not been studied. METHODS: A cohort of 6152...... alcohol misusing men and women aged 15-83 were interviewed about drinking pattern and social issues and followed for 84,257 person-years. Outcome was alcoholic cirrhosis mortality. Data was analyzed by means of Cox-regression models. RESULTS: In this large prospective cohort study of alcohol misusers...... there was a 27 fold increased mortality from alcoholic cirrhosis in men and a 35 fold increased mortality from alcoholic cirrhosis in women compared to the Danish population. Number of drinks per day was not significantly associated with death from alcoholic cirrhosis, since there was no additional risk of death...

  3. Dose response curves for effects of low-level radiation

    International Nuclear Information System (INIS)

    Myers, D.K.

    1980-01-01

    The linear dose-response model used by international committees to assess the genetic and carcinogenic hazards of low-level radiation appears to be the most reasonable interpretation of the available scientific data that are relevant to this topic. There are, of course, reasons to believe that this model may overestimate radiation hazards in certain instances, a fact acknowledged in recent reports of these committees. The linear model is now also being utilized to estimate the potential carcinogenic hazards of other agents such as asbestos and polycyclic aromatic hydrocarbons. This model implies that there is no safe dose for any of these agents and that potential health hazards will increase in direct proportion to total accumulated dose. The practical implication is the recommendation that all exposures should be kept 'as low as reasonably achievable, economic and social factors being taken into account'. (auth)

  4. Dose-response curve estimation: a semiparametric mixture approach.

    Science.gov (United States)

    Yuan, Ying; Yin, Guosheng

    2011-12-01

    In the estimation of a dose-response curve, parametric models are straightforward and efficient but subject to model misspecifications; nonparametric methods are robust but less efficient. As a compromise, we propose a semiparametric approach that combines the advantages of parametric and nonparametric curve estimates. In a mixture form, our estimator takes a weighted average of the parametric and nonparametric curve estimates, in which a higher weight is assigned to the estimate with a better model fit. When the parametric model assumption holds, the semiparametric curve estimate converges to the parametric estimate and thus achieves high efficiency; when the parametric model is misspecified, the semiparametric estimate converges to the nonparametric estimate and remains consistent. We also consider an adaptive weighting scheme to allow the weight to vary according to the local fit of the models. We conduct extensive simulation studies to investigate the performance of the proposed methods and illustrate them with two real examples. © 2011, The International Biometric Society.

  5. Multifraction dose response of growing and resting phase hair follicles

    International Nuclear Information System (INIS)

    Vegesna, V.; Withers, H.R.

    1987-01-01

    It has been established in both the clinic and the laboratory that there is a differentiation response to changes in dose per fraction in early and late responding tissues. To study one possible biological reason for differences in early and late responses. The authors selected one kind of cellular entity, the hair follicle, in two different phases of mitotic activity. The follicles are usually in a resting phase (7-12 wks), but mitotic activity can be initiated by plucking the club hairs. This was done on one half of the thorax and then exposing mice to doses of radiation (cesium gamma-ray). Dose responses for epilation between growing (early) and resting (late) follicles were compared for the same mouse. The fractionated response was studied by reducing the dose down to 2.5 Gy/fx. As the literature suggests, the total dose tolerated by a resting (late) follicle increased more than that for a growing (early) follicle

  6. Dose-response testing with nickel sulphate using the TRUE test in nickel-sensitive individuals. Multiple nickel sulphate patch-test reactions do not cause an 'angry back'

    DEFF Research Database (Denmark)

    Andersen, Klaus Ejner; Lidén, C; Hansen, J

    1993-01-01

    The aim of this study was to employ the TRUE test assay to confirm the presence or absence of the 'angry back' phenomenon, i.e. that a strong positive patch-test reaction heightens adjacent patch-test response. In addition, we wished to establish the dose-response relationship for nickel sulphate...... back' phenomenon was not apparent in this study, as the spill-over effect was not statistically significant. Strong reactions to high concentrations of nickel sulphate did not enhance the response to adjacent lower concentrations of nickel sulphate....

  7. Does a dose-response relation exist between spinal pain and temporomandibular disorders?

    Directory of Open Access Journals (Sweden)

    Englund Erling

    2009-03-01

    Full Text Available Abstract Background The aim of this study was to test whether a reciprocal dose-response relation exists between frequency/severity of spinal pain and temporomandibular disorders (TMD. Methods A total of 616 subjects with varying severity of spinal pain or no spinal pain completed a questionnaire focusing on symptoms in the jaw, head and spinal region. A subset of the population (n = 266 were sampled regardless of presence or absence of spinal pain. We used two different designs, one with frequency/severity of spinal pain, and the other, with frequency/severity of TMD symptoms as independent variable. All 616 participants were allocated to four groups, one control group without spinal pain and three spinal pain groups. The subjects in the subset were allocated to one control group without TMD symptoms and three TMD groups. Odds ratios (ORs were calculated for presence of frequent TMD symptoms in the separate spinal pain groups as well as for frequent spinal pain in the separate TMD groups. Results The analysis showed increasing ORs for TMD with increasing frequency/severity of spinal pain. We also found increasing ORs for spinal pain with increasing frequency/severity of TMD symptoms. Conclusion This study shows a reciprocal dose-response-like relationship between spinal pain and TMD. The results indicate that these two conditions may share common risk factors or that they may influence each other. Studies on the temporal sequence between spinal pain and TMD are warranted.

  8. Dose - Response Curves for Dicentrics and PCC Rings: Preparedness for Radiological Emergency in Thailand

    International Nuclear Information System (INIS)

    Rungsimaphorn, B.; Rerkamnuaychoke, B.; Sudprasert, W.

    2014-01-01

    Establishing in-vitro dose calibration curves is important for reconstruction of radiation dose in the exposed individuals. The aim of this pioneering work in Thailand was to generate dose-response curves using conventional biological dosimetry: dicentric chromosome assay (DCA) and premature chromosome condensation (PCC) assay. The peripheral blood lymphocytes were irradiated with 137 Cs at a dose rate of 0.652 Gy/min to doses of 0.1, 0.25, 0.5, 0.75, 1, 2, 3, 4 and 5 Gy for DCA technique, and 5, 10, 15, 20 and 25 Gy for PCC technique. The blood samples were cultured and processed following the standard procedure given by the IAEA with slight modifications. At least 500-1,000 metaphases or 100 dicentrics/ PCC rings were analyzed using an automated metaphase finder system. The yield of dicentrics with dose was fitted to a linear quadratic model using Chromosome Aberration Calculation Software (CABAS, version 2.0), whereas the dose-response curve of PCC rings was fitted to a linear relationship. These curves will be useful for in-vitro dose reconstruction and can support the preparedness for radiological emergency in the country.

  9. Hierarchical Bayesian inference for ion channel screening dose-response data [version 2; referees: 2 approved

    Directory of Open Access Journals (Sweden)

    Ross H Johnstone

    2017-03-01

    Full Text Available Dose-response (or ‘concentration-effect’ relationships commonly occur in biological and pharmacological systems and are well characterised by Hill curves. These curves are described by an equation with two parameters: the inhibitory concentration 50% (IC50; and the Hill coefficient. Typically just the ‘best fit’ parameter values are reported in the literature. Here we introduce a Python-based software tool, PyHillFit , and describe the underlying Bayesian inference methods that it uses, to infer probability distributions for these parameters as well as the level of experimental observation noise. The tool also allows for hierarchical fitting, characterising the effect of inter-experiment variability. We demonstrate the use of the tool on a recently published dataset on multiple ion channel inhibition by multiple drug compounds. We compare the maximum likelihood, Bayesian and hierarchical Bayesian approaches. We then show how uncertainty in dose-response inputs can be characterised and propagated into a cardiac action potential simulation to give a probability distribution on model outputs.

  10. Developing guidelines for economic evaluation of environmental impacts in EIAs. Part II: Case studies and dose-response literature

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-07-01

    This Part II of the report contains full versions of the case studies for air, water and land (Chapters 2-4), which were only summarised in Part I. In addition, during the work the research team has collected a large amount of literature and information on dose response relationships for air and water pollution relevant to China. This information is included as Chapters 5 and 6.

  11. Developing guidelines for economic evaluation of environmental impacts in EIAs. Part II: Case studies and dose-response literature

    International Nuclear Information System (INIS)

    2005-01-01

    This Part II of the report contains full versions of the case studies for air, water and land (Chapters 2-4), which were only summarised in Part I. In addition, during the work the research team has collected a large amount of literature and information on dose response relationships for air and water pollution relevant to China. This information is included as Chapters 5 and 6

  12. The relationship between 19th century BMIs and family size: Economies of scale and positive externalities.

    Science.gov (United States)

    Carson, Scott Alan

    2015-04-01

    The use of body mass index values (BMI) to measure living standards is now a well-accepted method in economics. Nevertheless, a neglected area in historical studies is the relationship between 19th century BMI and family size, and this relationship is documented here to be positive. Material inequality and BMI are the subject of considerable debate, and there was a positive relationship between BMI and wealth and an inverse relationship with inequality. After controlling for family size and wealth, BMI values were related with occupations, and farmers and laborers had greater BMI values than workers in other occupations. Copyright © 2014 Elsevier GmbH. All rights reserved.

  13. Linear dose response curves in fungi and tradescantia

    International Nuclear Information System (INIS)

    Unrau, P.

    1999-07-01

    Tradescantia Clone 02 data suggests that linear non-threshold dose responses are expected to the lowest doses and dose rates of low linear energy transfer (LET) radiation. This is likely to be true for other living organisms even though Clone 02 is radiation sensitive. It is concluded that Clone 02 is partially defective in the RAD 6 pathway for the repair of DNA interstrand cross-links (ISCL) and other loss of coding damage (LCD), based on its cross sensitivities to EMS and ionizing radiation. Tradescantia Clone 02 data showing linear non-threshold induction of somatic genetic events in part reflects the repair deficiency of this Clone. More DNA damage is repaired by recombinational mechanisms in Clone 02 than would occur in a wild-type strain. Two important classes of DNA lesions are induced by ionizing radiation in DNA - double strand breaks (DSB) which are repaired by recombination mechanisms, and loss of coding information damage (LCD), which is repaired by error prone mechanisms but may also be a substrate for recombinational repair. Based on data from yeast, there are two different repair pathways which deal with these differing lesions with different somatic genetic consequences. From yeast, yield cross sections can be derived and applied to DNA damage and repair in Tradescantia. For Clone 02, per lesion, more visible genetic events are scored than in wild-type strains. In a radiation-derived sub-clone, Clone 0106, which is more variable than Clone 02, even more events occur per lesion. This derivative clone, plus breeding experiments, indicate that Clone 02 is heterozygous, or a 'carrier' for a mutant version of a gene in the Tradescantia RAD 6 repair pathway. Clone 02 is, therefore, much like a Fanconi's anemia carrier in a human population, while the Clone 0106 derivative is much like a homozygous Fanconi's anemia patient, with respect to its response to ionizing radiation damage. Two anomalies in its dose response curves for 'pink' loss of

  14. The Relationship Between Trust-in-God, Positive and Negative Affect, and Hope.

    Science.gov (United States)

    Fadardi, Javad S; Azadi, Zeinab

    2017-06-01

    We aimed to test the relationships between Trust-in-God, positive and negative affect, and feelings of hope. A sample of university students (N = 282, 50 % female) completed the Positive and Negative Affect Schedule, the Adult Dispositional Hope Scale, and a Persian measure of Trust-in-God for Muslims. The results of a series of hierarchical regression analyses indicated that Trust-in-God was positively associated with participants' scores for hope and positive affect but was negatively associated with their scores for negative affect. The results support the relationship between Trust-in-God and indices of mental health.

  15. Biophysical Monitoring and dose response characteristics of irradiated hemoglobin

    International Nuclear Information System (INIS)

    Elshemey, W.M; Selim, N.S.; Desouky, O.

    2003-01-01

    The present work aims to move a step forward towards a deeper understanding of the scattering of x-ray, from lyophilized biological samples. Comparative study has been performed using LAXS and UV-visible spectrophotometry for monitoring the dose response characteristics of the hemoglobin molecule of irradiated blood. Blood samples were irradiated at doses ranging from 5 up to 100 Gy. Diluted hemoglobin solution was scanned in the UV- visible range (200-700 nm), and lyophilized hemoglobin was prepared for LAXS measurement. The radiation-induced changes in the hemoglobin structure have been evaluated. The LAXS profile of hemoglobin molecule is characterized by the presence of two peaks in the forward direction of scattering. These peaks were found to be sensitive to the variations in the molecular structure of a given sample. The obtained results suggest that the 1 s t peak, recorded at 4.65 o , is sensitive to the tertiary and quaternary structure of the globin part, while the major peak, recorded at 10.5 o , appeared to be related to its primary and secondary structure

  16. The Relationship between Teacher Stress and Burnout in Hong Kong: Positive Humour and Gender as Moderators

    Science.gov (United States)

    Ho, Sammy K.

    2017-01-01

    In this study, we report on the relationship between positive humour and burnout among 379 secondary school teachers in Hong Kong, and explore whether the relationship varies according to gender. The moderating effects of both affiliative and self-enhancing humour on each burnout component were then examined. High affiliative and self-enhancing…

  17. Positive and Negative Emotions and Coping as Mediators of Mother-Child Attachment and Peer Relationships

    Science.gov (United States)

    Abraham, Michelle M.; Kerns, Kathryn A.

    2013-01-01

    This study examined whether emotions and coping explain (mediate) the association between mother-child attachment and peer relationships. Attachment, positive and negative emotion experience, coping, and peer relationships were examined in 106 fourth-grade through sixth-grade girls attending a 6-day residential camp. Attachment, experience of…

  18. 77 FR 45282 - NRC Position on the Relationship Between General Design Criteria and Technical Specification...

    Science.gov (United States)

    2012-07-31

    ... Position on the Relationship Between General Design Criteria and Technical Specification Operability AGENCY... relationship between the general design criteria (GDC) for nuclear power plants and technical specification... Communications Branch, Division of Policy and Rulemaking, Office Nuclear Reactor Regulation, Mail Stop: OWFN-12-D...

  19. Linear dose response curves in fungi and tradescantia

    Energy Technology Data Exchange (ETDEWEB)

    Unrau, P. [Atomic Energy of Canada Ltd., Chalk River, Ontario (Canada)

    1999-07-15

    Tradescantia Clone 02 data suggests that linear non-threshold dose responses are expected to the lowest doses and dose rates of low linear energy transfer (LET) radiation. This is likely to be true for other living organisms even though Clone 02 is radiation sensitive. It is concluded that Clone 02 is partially defective in the RAD 6 pathway for the repair of DNA interstrand cross-links (ISCL) and other loss of coding damage (LCD), based on its cross sensitivities to EMS and ionizing radiation. Tradescantia Clone 02 data showing linear non-threshold induction of somatic genetic events in part reflects the repair deficiency of this Clone. More DNA damage is repaired by recombinational mechanisms in Clone 02 than would occur in a wild-type strain. Two important classes of DNA lesions are induced by ionizing radiation in DNA - double strand breaks (DSB) which are repaired by recombination mechanisms, and loss of coding information damage (LCD), which is repaired by error prone mechanisms but may also be a substrate for recombinational repair. Based on data from yeast, there are two different repair pathways which deal with these differing lesions with different somatic genetic consequences. From yeast, yield cross sections can be derived and applied to DNA damage and repair in Tradescantia. For Clone 02, per lesion, more visible genetic events are scored than in wild-type strains. In a radiation-derived sub-clone, Clone 0106, which is more variable than Clone 02, even more events occur per lesion. This derivative clone, plus breeding experiments, indicate that Clone 02 is heterozygous, or a 'carrier' for a mutant version of a gene in the Tradescantia RAD 6 repair pathway. Clone 02 is, therefore, much like a Fanconi's anemia carrier in a human population, while the Clone 0106 derivative is much like a homozygous Fanconi's anemia patient, with respect to its response to ionizing radiation damage. Two anomalies in its dose response curves for &apos

  20. Cerebral radioprotection by pentobarbital: Dose-response characteristics and association with GABA agonist activity

    International Nuclear Information System (INIS)

    Olson, J.J.; Friedman, R.; Orr, K.; Delaney, T.; Oldfield, E.H.

    1990-01-01

    Pentobarbital reduces cerebral radiation toxicity; however, the mechanism of this phenomenon remains unknown. As an anesthetic and depressant of cerebral metabolism, pentobarbital induces its effects on the central nervous system by stimulating the binding of gamma-aminobutyric acid (GABA) to its receptor and by inhibiting postsynaptic excitatory amino acid activity. The purpose of this study is to investigate the role of these actions as well as other aspects of the radioprotective activity of pentobarbital. Fischer 344 rats were separated into multiple groups and underwent two dose-response evaluations. In one set of experiments to examine the relationship of radioprotection to pentobarbital dose, a range of pentobarbital doses (0 to 75 mg/kg) were given intraperitoneally prior to a constant-level radiation dose (70 Gy). In a second series of experiments to determine the dose-response relationship of radiation protection to radiation dose, a range of radiation doses (10 to 90 Gy) were given with a single pentobarbital dose. Further groups of animals were used to evaluate the importance of the timing of pentobarbital administration, the function of the (+) and (-) isomers of pentobarbital, and the role of an alternative GABA agonist (diazepam). In addition, the potential protective effects of alternative methods of anesthesia (ketamine) and induction of cerebral hypometabolism (hypothermia) were examined. Enhancement of survival time from acute radiation injury due to high-dose single-fraction whole-brain irradiation was maximal with 60 mg/kg of pentobarbital, and occurred over the range of all doses examined between 30 to 90 Gy. Protection was seen only in animals that received the pentobarbital before irradiation. Administration of other compounds that enhance GABA binding (Saffan and diazepam) also significantly enhanced survival time

  1. IRSL dating of K-feldspars: Modelling natural dose response curves to deal with anomalous fading and trap competition

    International Nuclear Information System (INIS)

    Kars, Romee H.; Wallinga, Jakob

    2009-01-01

    We recently proposed a model that reconstructs the natural dose response curve for K-rich feldspars, using laboratory fading measurements and dose response as input parameters. The model is based on the relationship between recombination centre density and trap lifetime. In this study we test the working of the model by comparing modelled feldspar ages with known quartz OSL ages of the same samples and with anomalous fading-corrected feldspar ages. The modelled feldspar ages are in good agreement with quartz OSL ages and corrected feldspar ages, opening possibilities for future use of the model on samples without independent age constraints. Furthermore, we investigate the effects of trap competition on the build-up of IRSL signal using two new variations of the model. Results show that incorporating trap competition into the model reduces the agreement between feldspar IRSL ages and quartz OSL ages.

  2. Positive Illusions in Adolescents: The Relationship between Academic Self-Enhancement and Depressive Symptomatology

    Science.gov (United States)

    Noble, Rick N.; Heath, Nancy L.; Toste, Jessica R.

    2011-01-01

    Positive illusions are systematically inflated self-perceptions of competence, and are frequently seen in areas of great difficulty. Although these illusions have been extensively documented in children and adults, their role in typical adolescent emotion regulation is unclear. This study investigated the relationship between positive illusions,…

  3. Distress Severity Following a Romantic Breakup is Associated with Positive Relationship Memories among Emerging Adults

    DEFF Research Database (Denmark)

    del Palacio Gonzalez, Adriana; Clark, David; O'Sullivan, Lucia

    2017-01-01

    symptoms has received little attention. We examined links between breakup-specific distress, depressive symptoms, and relationship memories of different valence. Ninety-one emerging adults (Mage = 20.13) who had experienced a recent romantic breakup recorded the frequency of positive and negative......Romantic relationship loss is associated with significant psychological distress for emerging adults. Intrusive memories of stressful events are typically associated with symptom severity; however, whether spontaneous positive memories of a relationship breakup may also be related to psychological...... spontaneous relationship memories in a four-day online memory diary. Control memories were also recorded. Positive memories were specifically related to breakup distress, whereas negative memories were related to both breakup distress and depression. No such associations were found for the control memories...

  4. Buffering effect of positive parent-child relationships on adolescent risk taking: A longitudinal neuroimaging investigation

    Science.gov (United States)

    Qu, Yang; Fuligni, Andrew J.; Galvan, Adriana; Telzer, Eva H.

    2015-01-01

    Adolescence is marked by a steep increase in risk-taking behavior. The serious consequences of such heightened risk taking raise the importance of identifying protective factors. Despite its dynamic change during adolescence, family relationships remain a key source of influence for teenagers. Using a longitudinal fMRI approach, we scanned 23 adolescents twice across a 1.5-year period to examine how changes in parent-child relationships contribute to changes in adolescent risk taking over time via changes in adolescents’ neural reactivity to rewards. Results indicate that although parent-child relationships are not associated with adolescent risk taking concurrently, increases in positive parent-child relationships contribute to declines in adolescent risk taking. This process is mediated by longitudinal decreases in ventral striatum activation to rewards during risk taking. Findings highlight the neural pathways through which improvements in positive parent-child relationships serve to buffer longitudinal increases in adolescent risk taking. PMID:26342184

  5. Positivity and job burnout in emergency personnel: examining linear and curvilinear relationship

    Directory of Open Access Journals (Sweden)

    Basińska Beata Aleksandra

    2017-06-01

    Full Text Available The aim of this study was to examine whether the relationship between the ratio of job-related positive to negative emotions (positivity ratio and job burnout is best described as linear or curvilinear. Participants were 89 police officers (12% women and 86 firefighters. The positivity ratio was evaluated using the Job-related Affective Wellbeing Scale (Van Katwyk, Fox, Spector, & Kelloway, 2000. Exhaustion and disengagement, two components of job burnout, were measured using the Oldenburg Burnout Inventory (Demerouti, Mostert, & Bakker, 2010. The results of regression analysis revealed that curvilinear relationships between the positivity ratio and two components of job burnout appeared to better fit the data than linear relationships. The relationship between the positivity ratio and exhaustion was curvilinear with a curve point at around 2.1. A similar curvilinear relationship, but with a lower curve point, i.e., around 1.8, was observed for disengagement. It seems that beyond certain values there may be hidden costs of maintaining positive emotions at work. Also, the unequal curve points for subscales suggest that different dimensions of work-related functioning are variously prone to such costs.

  6. Shared dosimetry error in epidemiological dose-response analyses

    International Nuclear Information System (INIS)

    Stram, Daniel O.; Preston, Dale L.; Sokolnikov, Mikhail; Napier, Bruce; Kopecky, Kenneth J.; Boice, John; Beck, Harold; Till, John; Bouville, Andre; Zeeb, Hajo

    2015-01-01

    Radiation dose reconstruction systems for large-scale epidemiological studies are sophisticated both in providing estimates of dose and in representing dosimetry uncertainty. For example, a computer program was used by the Hanford Thyroid Disease Study to provide 100 realizations of possible dose to study participants. The variation in realizations reflected the range of possible dose for each cohort member consistent with the data on dose determinates in the cohort. Another example is the Mayak Worker Dosimetry System 2013 which estimates both external and internal exposures and provides multiple realizations of 'possible' dose history to workers given dose determinants. This paper takes up the problem of dealing with complex dosimetry systems that provide multiple realizations of dose in an epidemiologic analysis. In this paper we derive expected scores and the information matrix for a model used widely in radiation epidemiology, namely the linear excess relative risk (ERR) model that allows for a linear dose response (risk in relation to radiation) and distinguishes between modifiers of background rates and of the excess risk due to exposure. We show that treating the mean dose for each individual (calculated by averaging over the realizations) as if it was true dose (ignoring both shared and unshared dosimetry errors) gives asymptotically unbiased estimates (i.e. the score has expectation zero) and valid tests of the null hypothesis that the ERR slope β is zero. Although the score is unbiased the information matrix (and hence the standard errors of the estimate of β) is biased for β≠0 when ignoring errors in dose estimates, and we show how to adjust the information matrix to remove this bias, using the multiple realizations of dose. The use of these methods in the context of several studies including, the Mayak Worker Cohort, and the U.S. Atomic Veterans Study, is discussed

  7. SU-F-J-86: Method to Include Tissue Dose Response Effect in Deformable Image Registration

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, J; Liang, J; Chen, S; Qin, A; Yan, D [Beaumont Health Systeml, Royal Oak, MI (United States)

    2016-06-15

    Purpose: Organ changes shape and size during radiation treatment due to both mechanical stress and radiation dose response. However, the dose response induced deformation has not been considered in conventional deformable image registration (DIR). A novel DIR approach is proposed to include both tissue elasticity and radiation dose induced organ deformation. Methods: Assuming that organ sub-volume shrinkage was proportional to the radiation dose induced cell killing/absorption, the dose induced organ volume change was simulated applying virtual temperature on each sub-volume. Hence, both stress and heterogeneity temperature induced organ deformation. Thermal stress finite element method with organ surface boundary condition was used to solve deformation. Initial boundary correspondence on organ surface was created from conventional DIR. Boundary condition was updated by an iterative optimization scheme to minimize elastic deformation energy. The registration was validated on a numerical phantom. Treatment dose was constructed applying both the conventional DIR and the proposed method using daily CBCT image obtained from HN treatment. Results: Phantom study showed 2.7% maximal discrepancy with respect to the actual displacement. Compared with conventional DIR, subvolume displacement difference in a right parotid had the mean±SD (Min, Max) to be 1.1±0.9(−0.4∼4.8), −0.1±0.9(−2.9∼2.4) and −0.1±0.9(−3.4∼1.9)mm in RL/PA/SI directions respectively. Mean parotid dose and V30 constructed including the dose response induced shrinkage were 6.3% and 12.0% higher than those from the conventional DIR. Conclusion: Heterogeneous dose distribution in normal organ causes non-uniform sub-volume shrinkage. Sub-volume in high dose region has a larger shrinkage than the one in low dose region, therefore causing more sub-volumes to move into the high dose area during the treatment course. This leads to an unfavorable dose-volume relationship for the normal organ

  8. Using nurse managers' perceptions to guide new graduates toward positive nurse relationships.

    Science.gov (United States)

    Moore, Linda Weaver; Sublett, Cynthia; Leahy, Cathy; Bradley, Jennifer M

    One of the greatest challenges new graduates confront when transitioning to practice is establishing positive relationships with experienced nurses. Nursing faculty must prepare graduates for this challenge. However, nursing faculty are often removed from everyday practice and must rely on the perceptions of those entrenched in practice in order to ground teaching endeavors in authenticity. Nurse managers are well positioned to provide knowledgeable insights to nursing faculty regarding nurse relationships. The purpose of this qualitative, descriptive study was to explore nurse managers' perceptions regarding new graduates' relationships with more experienced nurses. Researcher-participant audiotaped interviews were conducted with 13 nurse managers. A content analysis revealed that all participants believed nurse relationships were significant, that factors such as perceived inequities and stressful occurrences triggered poor relationships, that new graduates were often targeted for negative relationships, and that reasons for targeting of new graduates included prolonged dependence on experienced nurses and either over or under confidence of the new graduate. Providing a supportive, protective environment and hiring practices that promote team unity were posed as strategies that could help to prevent targeting of new graduates. Findings provide real-life, practice based information that can underpin nurse educators' teaching regarding nurse relationships and relationship building. Copyright © 2017 Elsevier Inc. All rights reserved.

  9. A randomized, dose-response study of sugammadex given for the reversal of deep rocuronium- or vecuronium-induced neuromuscular blockade under sevoflurane anesthesia

    DEFF Research Database (Denmark)

    Duvaldestin, Philippe; Kuizenga, Karel; Saldien, Vera

    2010-01-01

    Sugammadex is the first of a new class of selective muscle relaxant binding drugs developed for the rapid and complete reversal of neuromuscular blockade induced by rocuronium and vecuronium. Many studies have demonstrated a dose-response relationship with sugammadex for reversal of neuromuscular...

  10. Personal and Environmental Resources Mediate the Positivity-Emotional Dysfunction Relationship.

    Science.gov (United States)

    Lehrer, H Matthew; Janus, Katherine C; Gloria, Christian T; Steinhardt, Mary A

    2017-03-01

    We investigated the relationships among positivity, perceived personal and environmental resources, and emotional dysfunction in adolescent girls. We hypothesized that perceived resources would mediate the relationship between positivity and emotional dysfunction. Participants (N = 510) attending an all-girls public school completed a survey assessing emotional dysfunction (depressive symptoms and perceived stress), positivity (positive/negative emotions), and personal/ environmental resources (resilience, hope, percent adaptive coping, community connectedness, social support, and school connectedness). Perceived resources were combined into one latent variable, and structural equation modeling tested the mediating effect of perceived resources on the relationship between positivity and emotional dysfunction. The model accounted for 63% of the variance in emotional dysfunction. Positivity exerted a significant direct effect on emotional dysfunction (β = -.14, p emotional dysfunction is primarily but not entirely mediated by perceived personal and environmental resources. Schools should consider strategies to enhance experiences of positive emotions and/or decrease experiences of negative emotions, in conjunction with encouraging student awareness and development of personal and environmental resources.

  11. The positives of negative emotions: willingness to express negative emotions promotes relationships.

    Science.gov (United States)

    Graham, Steven M; Huang, Julie Y; Clark, Margaret S; Helgeson, Vicki S

    2008-03-01

    Four studies support the hypothesis that expressing negative emotion is associated with positive relationship outcomes, including elicitation of support, building of new close relationships, and heightening of intimacy in the closest of those relationships. In Study 1, participants read vignettes in which another person was experiencing a negative emotion. Participants reported they would provide more help when the person chose to express the negative emotion. In Study 2, participants watched a confederate preparing for a speech. Participants provided more help to her when she expressed nervousness. In Study 3, self-reports of willingness to express negative emotions predicted having more friends, controlling for demographic variables and extraversion. In Study 4, self-reports of willingness to express negative emotion measured prior to arrival at college predicted formation of more relationships, greater intimacy in the closest of those relationships, and greater received support from roommates across participants' first semester of college.

  12. Autonomy, positive relationships, and IL-6: evidence for gender-specific effects.

    Science.gov (United States)

    Eisenlohr-Moul, Tory; Segerstrom, Suzanne

    2013-05-01

    A body of evidence indicates that women value relationship-centred aspects of well-being more than men do, while men value autonomy-centred aspects of well-being more than women do. The current study examined whether gender moderates relations between autonomy and positive relationships and interleukin-6 (IL-6), a cytokine associated with inflammatory processes. Aspects of well-being consistent with gender-linked values were expected to be most health protective such that positive relationships would predict lower IL-6 only or more strongly in women, and autonomy would predict lower IL-6 only or more strongly in men. In the first study, a sample of 119 older adults (55% female) living in Kentucky were visited in their homes for interviews and blood draws. In the second study, a sample of 1,028 adults (45% female) living across the United States underwent a telephone interview followed by a visit to a research centre for blood draws. In the Kentucky sample, autonomy was quadratically related to IL-6 such that moderate autonomy predicted higher IL-6; this effect was stronger in men. In the US national sample, more positive relationships were associated with lower IL-6 in women only. When the national sample was restricted to match the Kentucky sample, moderate autonomy was again associated with higher IL-6 in men only. Results provide preliminary evidence for gender-specific effects of positive relationships and autonomy on IL-6. Further work is needed to establish the generalizability of these effects to different ages, cultures, and health statuses. What is already known on this subject? A host of previous work indicates that women value relationship-centred aspects of well-being more than men, while men value autonomy-centred aspects of well-being more than women. Further, there is some evidence suggesting that well-being consistent with gender-linked values is more health protective, such that relationships are more protective for women than for men, while

  13. Salvage Radiation Therapy Dose Response for Biochemical Failure of Prostate Cancer After Prostatectomy—A Multi-Institutional Observational Study

    Energy Technology Data Exchange (ETDEWEB)

    Pisansky, Thomas M., E-mail: pisansky.thomas@mayo.edu [Department of Radiation Oncology, Mayo Clinic, Rochester, Minnesota (United States); Agrawal, Shree [Case Western Reserve University School of Medicine, Cleveland, Ohio (United States); Hamstra, Daniel A. [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Koontz, Bridget F. [Department of Radiation Oncology, Duke Cancer Institute, Durham, North Carolina (United States); Liauw, Stanley L. [Department of Radiation and Cellular Oncology, University of Chicago, Chicago, Illinois (United States); Efstathiou, Jason A. [Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts (United States); Michalski, Jeff M. [Department of Radiation Oncology, Washington University, St. Louis, Missouri (United States); Feng, Felix Y. [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Abramowitz, Matthew C.; Pollack, Alan [Department of Radiation Oncology, University of Miami, Miami, Florida (United States); Anscher, Mitchell S. [Department of Radiation Oncology, Virginia Commonwealth University, Richmond, Virginia (United States); Moghanaki, Drew [Department of Radiation Oncology, Virginia Commonwealth University, Richmond, Virginia (United States); Hunter Holmes McGuire Veterans Administration Medical Center, Richmond, Virginia (United States); Den, Robert B. [Department of Radiation Oncology, Thomas Jefferson University, Philadelphia, Pennsylvania (United States); Stephans, Kevin L. [Department of Radiation Oncology, Cleveland Clinic, Cleveland, Ohio (United States); Zietman, Anthony L. [Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts (United States); Lee, W. Robert [Department of Radiation Oncology, Duke Cancer Institute, Durham, North Carolina (United States); Kattan, Michael W. [Department of Quantitative Health Sciences, Cleveland Clinic, Cleveland, Ohio (United States); and others

    2016-12-01

    Purpose: To determine whether a dose-response relationship exists for salvage radiation therapy (RT) of biochemical failure after prostatectomy for prostate cancer. Methods and Materials: Individual data from 1108 patients who underwent salvage RT at 10 academic centers were pooled. The cohort was enriched for selection criteria more likely associated with tumor recurrence in the prostate bed (margin positive and pre-RT prostate-specific antigen [PSA] level of ≤2.0 ng/mL) and without the confounding of planned androgen suppression. The cumulative incidence of biochemical failure and distant metastasis over time was computed, and competing risks hazard regression models were used to investigate the association between potential predictors and these outcomes. The association of radiation dose with outcomes was the primary focus. Results: With a 65.2-month follow-up duration, the 5- and 10-year estimates of freedom from post-RT biochemical failure (PSA level >0.2 ng/mL and rising) was 63.5% and 49.8%, respectively, and the cumulative incidence of distant metastasis was 12.4% by 10 years. A Gleason score of ≥7, higher pre-RT PSA level, extraprostatic tumor extension, and seminal vesicle invasion were associated with worse biochemical failure and distant metastasis outcomes. A salvage radiation dose of ≥66.0 Gy was associated with a reduced cumulative incidence of biochemical failure, but not of distant metastasis. Conclusions: The use of salvage radiation doses of ≥66.0 Gy are supported by evidence presented in the present multicenter pooled analysis of individual patient data. The observational reporting method, limited sample size, few distant metastasis events, modest follow-up duration, and elective use of salvage therapy might have diminished the opportunity to identify an association between the radiation dose and this endpoint.

  14. Salvage Radiation Therapy Dose Response for Biochemical Failure of Prostate Cancer After Prostatectomy—A Multi-Institutional Observational Study

    International Nuclear Information System (INIS)

    Pisansky, Thomas M.; Agrawal, Shree; Hamstra, Daniel A.; Koontz, Bridget F.; Liauw, Stanley L.; Efstathiou, Jason A.; Michalski, Jeff M.; Feng, Felix Y.; Abramowitz, Matthew C.; Pollack, Alan; Anscher, Mitchell S.; Moghanaki, Drew; Den, Robert B.; Stephans, Kevin L.; Zietman, Anthony L.; Lee, W. Robert; Kattan, Michael W.

    2016-01-01

    Purpose: To determine whether a dose-response relationship exists for salvage radiation therapy (RT) of biochemical failure after prostatectomy for prostate cancer. Methods and Materials: Individual data from 1108 patients who underwent salvage RT at 10 academic centers were pooled. The cohort was enriched for selection criteria more likely associated with tumor recurrence in the prostate bed (margin positive and pre-RT prostate-specific antigen [PSA] level of ≤2.0 ng/mL) and without the confounding of planned androgen suppression. The cumulative incidence of biochemical failure and distant metastasis over time was computed, and competing risks hazard regression models were used to investigate the association between potential predictors and these outcomes. The association of radiation dose with outcomes was the primary focus. Results: With a 65.2-month follow-up duration, the 5- and 10-year estimates of freedom from post-RT biochemical failure (PSA level >0.2 ng/mL and rising) was 63.5% and 49.8%, respectively, and the cumulative incidence of distant metastasis was 12.4% by 10 years. A Gleason score of ≥7, higher pre-RT PSA level, extraprostatic tumor extension, and seminal vesicle invasion were associated with worse biochemical failure and distant metastasis outcomes. A salvage radiation dose of ≥66.0 Gy was associated with a reduced cumulative incidence of biochemical failure, but not of distant metastasis. Conclusions: The use of salvage radiation doses of ≥66.0 Gy are supported by evidence presented in the present multicenter pooled analysis of individual patient data. The observational reporting method, limited sample size, few distant metastasis events, modest follow-up duration, and elective use of salvage therapy might have diminished the opportunity to identify an association between the radiation dose and this endpoint.

  15. Positive academic emotions moderate the relationship between self-regulation and academic achievement.

    Science.gov (United States)

    Villavicencio, Felicidad T; Bernardo, Allan B I

    2013-06-01

    Research has shown how academic emotions are related to achievement and to cognitive/motivational variables that promote achievement. Mediated models have been proposed to account for the relationships among academic emotions, cognitive/motivational variables, and achievement, and research has supported such mediated models, particularly with negative emotions. The study tested the hypotheses: (1) self-regulation and the positive academic emotions of enjoyment and pride are positive predictors of achievement; and (2) enjoyment and pride both moderate the relationship between self-regulation and achievement. Participants were 1,345 students enrolled in various trigonometry classes in one university. Participants answered the Academic Emotions Questionnaire-Math (Pekrun, Goetz, & Frenzel, 2005) and a self-regulation scale (Pintrich, Smith, Garcia, & McKeachie, 1991) halfway through their trigonometry class. The students' final grades in the course were regressed to self-regulation, positive emotions, and the interaction terms to test the moderation effects. Enjoyment and pride were both positive predictors of grades; more importantly, both moderated the relationship between self-regulation and grades. For students who report higher levels of both positive emotions, self-regulation was positively associated with grades. However, for those who report lower levels of pride, self-regulation was not related to grades; and, for those who reported lower levels of enjoyment, self-regulation was negatively related to grades. The results are discussed in terms of how positive emotions indicate positive appraisals of task/outcome value, and thus enhance the positive links between cognitive/motivational variables and learning. ©2012 The British Psychological Society.

  16. On the relationship between positive and negative affect: Their correlation and their co-occurrence.

    Science.gov (United States)

    Larsen, Jeff T; Hershfield, Hal E; Stastny, Bradley J; Hester, Neil

    2017-03-01

    Understanding the nature of emotional experience requires understanding the relationship between positive and negative affect. Two particularly important aspects of that relationship are the extent to which positive and negative affect are correlated with one another and the extent to which they co-occur. Some researchers have assumed that weak negative correlations imply greater co-occurrence (i.e., more mixed emotions) than do strong negative correlations, but others have noted that correlations may imply very little about co-occurrence. We investigated the relationship between the correlation between positive and negative affect and co-occurrence. Participants in each of 2 samples provided moment-to-moment happiness and sadness ratings as they watched an evocative film and listened to music. Results indicated (a) that 4 measures of the correlation between positive and negative affect were quite highly related to 1 another; (b) that the strength of the correlation between measures of mixed emotions varied considerably; (c) that correlational measures were generally (but not always) weakly correlated with mixed emotion measures; and (d) that bittersweet stimuli consistently led to elevations in mixed emotion measures but did not consistently weaken the correlation between positive and negative affect. Results highlight that the correlation between positive and negative affect and their co-occurrence are distinct aspects of the relationship between positive and negative affect. Such insight helps clarify the implications of existing work on age-related and cultural differences in emotional experience and sets the stage for greater understanding of the experience of mixed emotions. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  17. Applying the Nominal Response Model within a Longitudinal Framework to Construct the Positive Family Relationships Scale

    Science.gov (United States)

    Preston, Kathleen Suzanne Johnson; Parral, Skye N.; Gottfried, Allen W.; Oliver, Pamella H.; Gottfried, Adele Eskeles; Ibrahim, Sirena M.; Delany, Danielle

    2015-01-01

    A psychometric analysis was conducted using the nominal response model under the item response theory framework to construct the Positive Family Relationships scale. Using data from the Fullerton Longitudinal Study, this scale was constructed within a long-term longitudinal framework spanning middle childhood through adolescence. Items tapping…

  18. Effects of Parent-Child Relationship on the Primary School Children's Non-Violence Position Formation

    Science.gov (United States)

    Valeeva, Roza A.; Kalimullin, Aydar M.

    2016-01-01

    The aim of the research was to identify and test experimentally the impact of parent-child relationship on the formation of the primary school children non-violence position. During the research the effectiveness of the correctional and development program "Together with my mom" was verified to promote parent-child interaction, as well…

  19. The Relationships between Language Learning Strategies and Positive Emotions among Malaysian ESL Undergraduates

    Science.gov (United States)

    Mohammadipour, Mohammad; Rashid, Sabariah Md; Rafik-Galea, Shameem; Thai, Yap Ngee

    2018-01-01

    Emotions are an indispensable part of second language learning. The aim of this study is to determine the relationship between the use of language learning strategies and positive emotions. The present study adopted a sequential mixed methods design. The participants were 300 Malaysian ESL undergraduates selected through stratified random sampling…

  20. Positive teacher–student relationships go beyond the classroom, problematic ones stay inside

    NARCIS (Netherlands)

    C. A. Claessens, Luce|info:eu-repo/dai/nl/357401530; van Tartwijk, Jan|info:eu-repo/dai/nl/112629385; C. van der Want, Anna; Pennings, Heleen|info:eu-repo/dai/nl/323242588; Verloop, Nico; J. den Brok, Perry; Wubbels, Theo|info:eu-repo/dai/nl/070651361

    2017-01-01

    The authors voice teachers' perceptions of their interpersonal experiences with students in both positive and problematic relationships. Interview data from 28 teachers were examined by coding utterances on teacher and student interactions. Results indicate that teachers defined the quality of the

  1. Investigating the Relationship among Internet Addiction, Positive and Negative Affects, and Life Satisfaction in Turkish Adolescents

    Science.gov (United States)

    Telef, Bülent Baki

    2016-01-01

    This study investigates the relationships between Internet addiction and the areas of life satisfaction and positive or negative affects in Turkish adolescents. The research sample comprised 358 students studying in the sixth, seventh and eighth grades at four different middle schools in Canakkale city centre during the 2012-2013 academic year, of…

  2. Analyzing the Relationship between Positive Psychological Capital and Organizational Commitment of the Teachers

    Science.gov (United States)

    Yalcin, Sinan

    2016-01-01

    In this study it was aimed to determine the relationship between teachers' positive psychological capital levels and organisational commitment. The study was conducted as a correlational survey which is one of the quantitative methods. The sample group consists of 244 teachers selected by using random sampling method among 1270 teachers working in…

  3. The Relationships between Positive Thinking Skills, Academic Locus of Control and Grit in Adolescents

    Science.gov (United States)

    Çelik, Ismail; Sariçam, Hakan

    2018-01-01

    The main purpose of this study is to examine the possible relationships between academic locus of control, positive thinking skills and grit in high school students. The participants of the research are composed of 288 adolescents continuing their high school education from 4 different schools in Agri, Turkey, which were selected with convenient…

  4. Testing Theoretical Relationships: Factors Influencing Positive Health Practices (PHP) in Filipino College Students

    Science.gov (United States)

    Ayres, Cynthia; Mahat, Ganga; Atkins, Robert

    2013-01-01

    Objective: To examine variables influencing the positive health practices (PHP) of Filipino college students to gain a better understanding of health practices in this ethnic/racial group. Cross-sectional study tested theoretical relationships postulated among (a) PHP, (b) social support (SS), (c) optimism, and (d) acculturation. Participants: A…

  5. Dose-response analysis of parotid gland function: what is the best measure of xerostomia?

    Science.gov (United States)

    Miah, Aisha B; Gulliford, Sarah L; Clark, Catharine H; Bhide, Shreerang A; Zaidi, Shane H; Newbold, Kate L; Harrington, Kevin J; Nutting, Christopher M

    2013-03-01

    To describe the dose-response relationships for the different measures of salivary gland recovery following radical radiotherapy for locally advanced head and neck squamous cell cancers (LA-HNSCC). Dosimetric analysis of data from the PARSPORT trial, a Phase III study of conventional RT (RT) and intensity modulated radiotherapy (IMRT) for LA-HNSCC was undertaken to determine the relationship between parotid gland mean dose and toxicity endpoints: high-grade subjective and objective xerostomia and xerostomia-related quality of life scores. LKB-NTCP parameters (TD50, m and n) were generated and tolerance doses (D50) reported using non-linear logistic regression analysis. Data were available on 63 patients from the PARSPORT trial. Parotid saliva flow rate provided the strongest association between mean dose and recovery, D50=23.4 Gy (20.6-26.2) and k=3.2 (1.9-4.5), R(2)=0.85. Corresponding LKB parameters were TD50=26.3 Gy (95% CI: 24.0-30.1), m=0.25 (0.18-1.0 and n=1). LENTSOMA subjective xerostomia also demonstrated a strong association D50=33.3 Gy (26.7-39.8), k=2.8 (91.4-4.4), R(2)=0.77). We recommend using the LENT SOMA subjective xerostomia score to predict recovery of salivation due to its strong association with dosimetry and ease of recording. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  6. Three-dimensional dose-response models of risk for radiation injury carcinogenesis

    International Nuclear Information System (INIS)

    Raabe, O.G.

    1988-01-01

    The use of computer graphics in conjunction with three-dimensional models of dose-response relationships for chronic exposure to ionizing radiation dramaticly clarifies the separate and interactive roles of competing risks. The three dimensions are average dose rate, exposure time, and risk. As an example, the functionally injurious and carcinogenic responses after systemic uptake of Ra-226 by beagles, mice and people with consequent alpha particle irradiation of the bone are represented by three-dimensional dose-rate/time/response surfaces that demonstrate the contributions with the passage of time of the competing deleterious responses. These relationships are further evaluated by mathematical stripping with three-dimensional illustrations that graphically show the resultant separate contribution of each effect. Radiation bone injury predominates at high dose rates and bone cancer at intermediate dose rates. Low dose rates result in spontaneous deaths from natural aging, yielding a type of practical threshold for bone cancer induction. Risk assessment is benefited by the insights that become apparent with these three-dimensional models. The improved conceptualization afforded by them contributes to planning and evaluating epidemiological analyses and experimental studies

  7. Researcher-researched relationship in qualitative research: Shifts in positions and researcher vulnerability.

    Science.gov (United States)

    Råheim, Målfrid; Magnussen, Liv Heide; Sekse, Ragnhild Johanne Tveit; Lunde, Åshild; Jacobsen, Torild; Blystad, Astrid

    2016-01-01

    The researcher role is highly debated in qualitative research. This article concerns the researcher-researched relationship. A group of health science researchers anchored in various qualitative research traditions gathered in reflective group discussions over a period of two years. Efforts to establish an anti-authoritarian relationship between researcher and researched, negotiation of who actually "rules" the research agenda, and experiences of shifts in "inferior" and "superior" knowledge positions emerged as central and intertwined themes throughout the discussions. The dual role as both insider and outsider, characteristic of qualitative approaches, seemed to lead to power relations and researcher vulnerability which manifested in tangible ways. Shifting positions and vulnerability surfaced in various ways in the projects. They nonetheless indicated a number of similar experiences which can shed light on the researcher-researched relationship. These issues could benefit from further discussion in the qualitative health research literature.

  8. Relationship between Cnm-positive Streptococcus mutans and cerebral microbleeds in humans.

    Science.gov (United States)

    Miyatani, F; Kuriyama, N; Watanabe, I; Nomura, R; Nakano, K; Matsui, D; Ozaki, E; Koyama, T; Nishigaki, M; Yamamoto, T; Mizuno, T; Tamura, A; Akazawa, K; Takada, A; Takeda, K; Yamada, K; Nakagawa, M; Ihara, M; Kanamura, N; Friedland, R P; Watanabe, Y

    2015-10-01

    Cerebral hemorrhage has been shown to occur in animals experimentally infected with Streptococcus mutans carrying the collagen-binding Cnm gene. However, the relationship between cerebral microbleeds and oral hygiene, with a focus on Cnm gene-positive S. mutans infection, remains unclear. One hundred and thirty-nine subjects participated. The presence or absence of Cnm-positive S. mutans and its collagen-binding activity were investigated using saliva samples, and relationship with cerebral microbleeds detected on MRI investigated, including clinical information and oral parameters. Fifty-one subjects were identified as Cnm-positive S. mutans carriers (36.7%), with cerebral microbleeds being detected in 43 (30.9%). A significantly larger number of subjects carried Cnm-positive S. mutans in the cerebral microbleeds (+) group. S. mutans with Cnm collagen-binding ability was detected in 39 (28.1%) of all subjects, and the adjusted odds ratio for cerebral microbleeds in the Cnm-positive group was 14.4. Regarding the presence of cerebral microbleeds, no significant differences were noted in the number of remaining teeth, dental caries, or in classic arteriosclerosis risk factors. The occurrence of cerebral microbleeds was higher in subjects carrying Cnm-positive S. mutans, indicating that the presence of Cnm-positive S. mutans increases cerebral microbleeds, and is an independent risk for the development of cerebrovascular disorders. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  9. Relationships matter: contraceptive choices among HIV-positive women in Tanzania.

    Science.gov (United States)

    Nyanja, Tabitha Alexandria Njeri; Tulinius, Charlotte

    2017-07-01

    Efforts to eliminate mother-to-child transmission of HIV in Tanzania are guided by a four-prong strategy advocated by the World Health Organization (WHO). Prong 2, prevention of unintended pregnancies among women living with HIV, has, however, received the least attention and contraceptive use to prevent unintended pregnancies remains low. This study explored the perceived barriers to the use of modern methods of contraception, and factors influencing contraceptive choice among HIV-positive women in urban Dar-es-Salaam, Tanzania. A qualitative multi-site study was conducted, utilising in-depth interviews and focus group discussions with 37 sexually active HIV-positive women aged between 20 and 44 years, attending three health facilities within Dar-es-Salaam. The theoretical framework was a patient centred model. Four barriers were identified: the influence of the women's spousal relationships; personal beliefs and the relationship of these in understanding her disease; the influence of the social demands on the woman and her relationships; and the importance of a woman's relationship with her healthcare provider/healthcare system. Being the bearers of bad news (HIV-positive status) the pregnant women experienced conflicts, violence, abandonment and rejection. The loss in negotiating power for the women was in relation to their intimate partners, but also in the patient-healthcare provider relationship. The role of the male partner as a barrier to contraceptive use cannot be understated. Therefore, the results suggest that healthcare providers should ensure patient-focused education and provide support that encompasses the importance of their relationships. Additional research is required to elucidate the functional association between contraceptive choices and personal and social relationships.

  10. Positive affect, negative affect, stress, and social support as mediators of the forgiveness-health relationship.

    Science.gov (United States)

    Green, Michelle; Decourville, Nancy; Sadava, Stanley

    2012-01-01

    Structural equation modeling was used to test a model in which positive affect, negative affect, perceived stress, and social support were hypothesized to mediate the relationship between forgiveness and mental and physical health. Six hundred and twenty-three undergraduates completed a battery of self-report measures. Results of the analyses indicated that the forgiveness-health relation was mediated by positive affect, negative affect, stress, and the interrelationship between negative affect and stress. There was limited support for social support and the interrelationship between positive affect and social support as mediators. The results suggested that the relationship between forgiveness and health is mediated rather than direct. Implications and directions for future research are discussed.

  11. Radiotherapy in addition to radical surgery in rectal cancer: evidence for a dose-response effect favoring preoperative treatment

    International Nuclear Information System (INIS)

    Glimelius, Bengt; Isacsson, Ulf; Jung, Bo; Paahlman, Lars

    1997-01-01

    Purpose: This study explored the relationship between radiation dose and reduction in local recurrence rate after preoperative and postoperative radiotherapy in rectal cancer. Methods and Materials: All randomized trials initiated prior to 1988 comparing preoperative and postoperative radiotherapy with surgery alone or with each other were included. Local failure rates were available in 5626 randomized patients. The linear quadratic formula was used to compensate for different radiotherapy schedules. Results: For preoperative radiotherapy, a clear dose-response relationship could be established. For postoperative radiotherapy, the range of doses was narrow, and a dose-response relationship could not be demonstrated. At similar doses, preoperative radiotherapy appeared to be more efficient in reducing local failure rate than postoperative. The only trial comparing preoperative with postoperative radiotherapy confirms this notion. A 15-20 Gy higher dose may be required postoperatively than preoperatively to reach similar efficacy. Neither approach alone significantly influences survival, although it is likely that a small survival benefit may be seen after preoperative radiotherapy. Conclusions: The information from the entire randomized experience suggests that preoperative radiotherapy may be more dose efficient than postoperative radiotherapy

  12. The Assessment of Positivity and Negativity in Social Networks: The Reliability and Validity of the Social Relationships Index

    Science.gov (United States)

    Campo, Rebecca A.; Uchino, Bert N.; Holt-Lunstad, Julianne; Vaughn, Allison; Reblin, Maija; Smith, Timothy W.

    2009-01-01

    The Social Relationships Index (SRI) was designed to examine positivity and negativity in social relationships. Unique features of this scale include its brevity and the ability to examine relationship positivity and negativity at the level of the specific individual and social network. The SRI's psychometric properties were examined in three…

  13. The Moderating Influence of Situational Motivation on the Relationship Between Preferred Exercise and Positive Affect

    Directory of Open Access Journals (Sweden)

    Eva Guérin

    2013-10-01

    Full Text Available Despite convincing evidence supporting the association between exercise and positive affect, this complex relationship requires further theoretical and person-centered explanation. The nature of one’s motivation for exercise, as postulated by Self-Determination Theory (SDT, may supply a missing and understudied link. The primary aim of this experimental study was to examine the moderating influence of situational motivation from SDT on the relationship between an acute bout of preferred exercise, namely running (vs. control, and changes in positive affect. Forty-one active women attended two sessions to engage in (a a 30-min moderate-intensity self-paced treadmill run and (b a 30-min quiet activity (i.e., newspaper reading. Participants with high introjection versus those with low introjection reported a greater increase in positive affect from pre- to postrunning and a greater decrease in positive affect from pre- to postcontrol. A “relief from guilt” effect was postulated to explain these results. Motivational variables accounted for 7% of variance in postrun positive affect. Consistent with SDT, running because one values this behavior and its benefits (i.e., identified regulation was significantly associated with postrun positive affect.

  14. Autonomy, Positive Relationships, and IL-6: Evidence for Gender-Specific Effects

    Science.gov (United States)

    Eisenlohr-Moul, Tory A.; Segerstrom, Suzanne C.

    2014-01-01

    Objectives A body of evidence indicates that women value relationship-centered aspects of well-being more than men do, while men value autonomy-centered aspects of well-being more than women do. The current study examined whether gender moderates relations between autonomy and positive relationships and interleukin-6 (IL-6), a cytokine associated with inflammatory processes. Aspects of well-being consistent with gender-linked values were expected to be most health-protective such that positive relationships would predict lower IL-6 only or more strongly in women, and autonomy would predict lower IL-6 only or more strongly in men. Methods In the first study, a sample of 119 older adults (55% female) living in Kentucky were visited in their homes for interviews and blood draws. In the second study, a sample of 1,028 adults (45% female) living across the United States (U.S.) underwent a telephone interview followed by a visit to a research center for blood draws. Results In the Kentucky sample, autonomy was quadratically related to IL-6 such that average autonomy predicted higher IL-6; this effect was stronger in men, providing support for our hypothesis only at above average levels of IL-6. In the U.S. national sample, more positive relationships were associated with lower IL-6 in women only. When the national sample was restricted to match the Kentucky sample, higher autonomy was associated with lower IL-6 in men only. Conclusions Results provide preliminary evidence for gender-specific effects of positive relationships and autonomy on IL-6. Further work is needed to establish the generalizability of these effects to different ages, cultures, and health statuses. PMID:22908985

  15. Association between tea consumption and risk of cognitive disorders: A dose-response meta-analysis of observational studies.

    Science.gov (United States)

    Liu, Xueying; Du, Xiaoyuan; Han, Guanying; Gao, Wenyuan

    2017-06-27

    The epidemiological evidence for a dose-response relationship between tea consumption and risk of cognitive disorders is sparse. The aim of the study was to summarize the evidence for the association of tea consumption with risk of cognitive disorders and assess the dose-response relationship. We searched electronic databases of Pubmed, Embase, and Cochrane Library (from 1965 to Jan 19, 2017) for eligible studies that published in the international journals. A random-effects model was used to pool the most adjusted odds ratios (ORs) and the corresponding 95% confidence intervals (CIs). Seventeen studies involving 48,435 participants were included in our study. The meta-analysis showed that a higher tea consumption was associated with a significant reduction in the risk of cognitive disorders (OR=0.73, 95% CI: 0.65-0.82). When considering the specific types of tea consumption, the significantly inverse association is only found in green tea consumption (OR=0.64, 95% CI: 0.53-0.77) but not in black/oolong tea consumption (OR=0.75, 95% CI: 0.55-1.01). Dose-response meta-analysis indicated that tea consumption is linearly associated with a reduced risk of cognitive disorders. An increment of 100 ml/day, 300 ml/day, and 500 ml/day of tea consumption was associated with a 6% (OR=0.94, 95% CI: 0.92-0.96), 19% (OR=0.81, 95% CI: 0.74-0.88), and 29% (OR=0.71, 95% CI: 0.62-0.82) lower risk of cognitive disorders. Tea consumption is inversely and linearly related to the risk of cognitive disorders. More studies are needed to further confirm our findings.

  16. Relationship of maxillary 3-dimensional posterior occlusal plane to mandibular spatial position and morphology.

    Science.gov (United States)

    Coro, Jorge C; Velasquez, Roberto L; Coro, Ivette M; Wheeler, Timothy T; McGorray, Susan P; Sato, Sadao

    2016-07-01

    The purpose of this study was to examine the relationship of the 3-dimensional (3D) posterior occlusal plane (POP) and the mandibular 3D spatial position. The relationship of the POP to mandibular morphology was also investigated. Retrospective data from a convenience sample of pretreatment diagnostic cone-beam computed tomography scans were rendered using InVivo software (Anatomage, San Jose, Calif). The sample consisted of 111 subjects (51 male, 60 female) and included growing and nongrowing subjects of different races and ethnicities. The 3D maxillary POP was defined by selecting the cusp tips of the second premolars and the second molars on the rendered images of the subjects. The angles made by this plane, in reference to the Frankfort horizontal plane, were measured against variables that described the mandibular position in the coronal, sagittal, and axial views. The POP was also compared with bilateral variables that described mandibular morphology. There were significant differences of the POP among the different skeletal malocclusions (P <0.0001). The POP showed significant correlations with mandibular position in the sagittal (P <0.0001), coronal (P <0.05), and axial (P <0.05) planes. The POP also showed a significant correlation with mandibular morphology (P <0.0001). These findings suggest that there is a distinct and significant relationship between the 3D POP and the mandibular spatial position and its morphology. Copyright © 2016 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

  17. Analysis of thermal-dose response to heat

    International Nuclear Information System (INIS)

    Storm, F.; Roe, D.; Drury, B.

    1987-01-01

    The authors reasoned that if hyperthermia alone has a clinical anti-tumor effect, response should have a thermal dose relationship. The authors analyzed 100 patients with advanced cancer treated with magnetic-induction. Three methods of determining thermal dose were used: (A) t1x10, the lowest temperature sustained throughout the tumor for 30-60min during the first of ten daily treatments, which represents one usual course of ten hourly sessions; (B) t43 (equivalent minutes at 43C) which accounts for non-linear tumor heating by combining serially measured temperatures during the first treatment with a mathematical description of the time-temperature relationship for thermal inactivation or damage; (C) Ct43 (cumulative t43), which represents the t43 value multiplied by the actual number of subsequent daily treatments received. Response was defined as CR+PR+MR. The results show a statistically significant effect of heat alone for t1x10, t43, and Ct43. These analyses demonstrate a thermal-dose relationship between hyperthermia therapy and tumor response as a sole independent variable, which indicates that heat therapy has clinical anti-cancer activity

  18. Structure-activity relationship studies of the aromatic positions in cyclopentapeptide CXCR4 antagonists

    DEFF Research Database (Denmark)

    Mungalpara, Jignesh; Zachariassen, Zack G; Thiele, Stefanie

    2013-01-01

    , and autoimmune diseases. While the structure-activity relationships for Arg(1), Arg(2), and Gly(4) are well established, less is understood about the roles of the aromatic residues 2-Nal(3) and D-Tyr(5). Here we report further structure-activity relationship studies of these two positions, which showed that (i......) the distal aromatic ring of the 2-Nal(3) side chain is required in order to maintain high potency and (ii) replacement of D-Tyr(5) with conformationally constrained analogues results in significantly reduced activity. However, a simplified analogue that contained Gly instead of D-Tyr(5) was only 13-fold less...

  19. The relationship of positive and negative expressiveness to the processing of emotion information.

    Science.gov (United States)

    Knyazev, Gennady G; Barchard, Kimberly A; Razumnikova, Olga M; Mitrofanova, Larisa G

    2012-06-01

    The tendency to express emotions non-verbally is positively related to perception of emotions in oneself. This study examined its relationship to perception of emotions in others. In 40 healthy adults, EEG theta synchronization was used to indicate emotion processing following presentation of happy, angry, and neutral faces. Both positive and negative expressiveness were associated with higher emotional sensitivity, as shown by cortical responses to facial expressions during the early, unconscious processing stage. At the late, conscious processing stage, positive expressiveness was associated with higher sensitivity to happy faces but lower sensitivity to angry faces. Thus, positive expressiveness predisposes people to allocate fewer attentional resources for conscious perception of angry faces. In contrast, negative expressiveness was consistently associated with higher sensitivity. The effects of positive expressiveness occurred in cortical areas that deal with emotions, but the effects of negative expressiveness occurred in areas engaged in self-referential processes in the context of social relationships. © 2012 The Authors. Scandinavian Journal of Psychology © 2012 The Scandinavian Psychological Associations.

  20. The Relationship Between Brain-Behavioral Systems and Negative and Positive Affect in Patients With Migraine

    Directory of Open Access Journals (Sweden)

    Jovharifard

    2015-08-01

    Full Text Available Background Migraine is a chronic headache disorder that affects approximately 12% of the general population. Migraine is known as recurrent headache, pulsating, moderate with severe power, which lasts for 4 to 72 hours, aggravated by daily physical activity along with nausea, vomiting, photophobia or photophobia. Objectives The purpose of this study was to investigate the relationship between brain-behavioral systems and negative and positive affects in patients with migraine. Patients and Methods The research population included patients, who had referred to neurology clinics. One hundred and twenty cases were selected by accessible sampling based on the neurologist’s diagnosis of migraine headaches. They completed the Gray-Wilson (1989 Personality Questionnaire as well as Watson, Clark and Telligent (1988 positive and negative affect scale. The data were analyzed using the SPSS 19 software, correlation and stepwise regression. Results The results showed that positive affect had a significant positive correlation with active avoidance parameters and negative significant correlation with passive avoidance and extinction parameters. The findings also indicated that negative affect had a positive and significant relationship with passive avoidance and extinction. Conclusions It can be concluded that brain-behavioral systems may be the foundation of behavioral and emotional tendencies in patients with migraine headaches.

  1. Digitoxin medication and cancer; case control and internal dose-response studies

    International Nuclear Information System (INIS)

    Haux, Johan; Klepp, Olbjørn; Spigset, Olav; Tretli, Steinar

    2001-01-01

    Digitoxin induces apoptosis in different human malignant cell lines in vitro. In this paper we investigated if patients taking digitoxin for cardiac disease have a different cancer incidence compared to the general population. Computer stored data on digitoxin concentrations in plasma from 9271 patients with cardiac disease were used to define a user population. Age and sex matched controls from the Norwegian Cancer Registry were used to calculate the number of expected cancer cases. The population on digitoxin showed a higher incidence of cancer compared to the control population. However, an additional analysis showed that the population on digitoxin had a general increased risk of cancer already, before the start on digitoxin. Leukemia/lymphoma were the cancer types which stood out with the highest risk in the digitoxin population before starting on digitoxin. This indicates that yet unknown risk factors exist for cardiovascular disease and lymphoproliferative cancer. An internal dose-response analysis revealed a relationship between high plasma concentration of digitoxin and a lower risk for leukemia/lymphoma and for cancer of the kidney/urinary tract. Morbidity and mortality are high in the population on digitoxin, due to high age and cardiac disease.These factors disturb efforts to isolate an eventual anticancer effect of digitoxin in this setting. Still, the results may indicate an anticancer effect of digitoxin for leukemia/lymphoma and kidney/urinary tract cancers. Prospective clinical cancer trials have to be done to find out if digitoxin and other cardiac glycosides are useful as anticancer agents

  2. A dose-response analysis for classical Kaposi's sarcoma management by radiotherapy

    International Nuclear Information System (INIS)

    Oysul, K.; Beyzadeoglu, M.; Surenkok, S.; Ozyigit, G.; Dirican, B.

    2008-01-01

    Objective was to evaluate the dose-response relationship in classical Kaposi's sarcoma CKS patients treated with external beam radiotherapy. Between 1993 and 2004, patients with CKS treated at the Department of Radiation Oncology, Gulhane Military Medical School, Ankara, Turkey were evaluated in this retrospective study. The median age at initial presentation was 60 years. First we analyzed the overall response rates for normalized total dose2Gy NTD2Gy of 20Gy. Secondly we searched for whether better response rates could be obtained with the NTD2Gy of >/=20Gy compared to the NTD2Gy of /20Gy and 64% and 24%for NDT2Gyof 20< Gy and these were statistically different p=0.001. Late side effects of radiation therapy were acceptable in all but 4 patients with fibrosis and edema. This retrospective analysis showed that radiotherapy schedules with an NDT2Gy of 20 Gy and above by using local irradiation fields are effective in terms of complete response rates in the management of CKS compared to NDT2Gy of < 20 Gy. (author)

  3. Quantifying the dose-response of walking in reducing coronary heart disease risk: meta-analysis.

    Science.gov (United States)

    Zheng, Henry; Orsini, Nicola; Amin, Janaki; Wolk, Alicja; Nguyen, Van Thi Thuy; Ehrlich, Fred

    2009-01-01

    The evidence for the efficacy of walking in reducing the risk of and preventing coronary heart disease (CHD) is not completely understood. This meta-analysis aimed to quantify the dose-response relationship between walking and CHD risk reduction for both men and women in the general population. Studies on walking and CHD primary prevention between 1954 and 2007 were identified through Medline, SportDiscus and the Cochrane Database of Systematic Reviews. Random-effect meta-regression models were used to pool the relative risks from individual studies. A total of 11 prospective cohort studies and one randomized control trial study met the inclusion criteria, with 295,177 participants free of CHD at baseline and 7,094 cases at follow-up. The meta-analysis indicated that an increment of approximately 30 min of normal walking a day for 5 days a week was associated with 19% CHD risk reduction (95% CI = 14-23%; P-heterogeneity = 0.56; I (2) = 0%). We found no evidence of heterogeneity between subgroups of studies defined by gender (P = 0.67); age of the study population (P = 0.52); or follow-up duration (P = 0.77). The meta-analysis showed that the risk for developing CHD decreases as walking dose increases. Walking should be prescribed as an evidence-based effective exercise modality for CHD prevention in the general population.

  4. Dose-Response of High-Intensity Training (HIT) on Atheroprotective miRNA-126 Levels

    Science.gov (United States)

    Schmitz, Boris; Schelleckes, Katrin; Nedele, Johanna; Thorwesten, Lothar; Klose, Andreas; Lenders, Malte; Krüger, Michael; Brand, Eva; Brand, Stefan-Martin

    2017-01-01

    Aim: MicroRNA-126 (miR-126) exerts beneficial effects on vascular integrity, angiogenesis, and atherosclerotic plaque stability. The purpose of this investigation was to analyze the dose-response relationship of high-intensity interval training (HIIT) on miR-126-3p and -5p levels. Methods: Sixty-one moderately trained individuals (females = 31 [50.8%]; 22.0 ± 1.84 years) were consecutively recruited and allocated into three matched groups using exercise capacity. During a 4-week intervention a HIIT group performed three exercise sessions/week of 4 × 30 s at maximum speed (all-out), a progressive HIIT (proHIIT) group performed three exercise sessions/week of 4 × 30 s at maximum speed (all-out) with one extra session every week (up to 7 × 30 s) and a low-intensity training (LIT) control group performed three exercise sessions/week for 25 min HIIT groups (after 4 min of high-intensity running). After the intervention, the LIT group presented an increase in miR-126-3p, while in the HIIT group, miR-126-3p levels were still reduced (all p HIIT (−1.05 ± 2.6 units). Conclusions: LIT and proHIIT may be performed to increase individual miR-126 levels. HIIT without progression was less effective in increasing miR-126. PMID:28611681

  5. Computational model of dose response for low-LET-induced complex chromosomal aberrations

    International Nuclear Information System (INIS)

    Eidelman, Y.A.; Andreev, S.G.

    2015-01-01

    Experiments with full-colour mFISH chromosome painting have revealed high yield of radiation-induced complex chromosomal aberrations (CAs). The ratio of complex to simple aberrations is dependent on cell type and linear energy transfer. Theoretical analysis has demonstrated that the mechanism of CA formation as a result of interaction between lesions at a surface of chromosome territories does not explain high complexes-to-simples ratio in human lymphocytes. The possible origin of high yields of γ-induced complex CAs was investigated in the present work by computer simulation. CAs were studied on the basis of chromosome structure and dynamics modelling and the hypothesis of CA formation on nuclear centres. The spatial organisation of all chromosomes in a human interphase nucleus was predicted by simulation of mitosis-to-interphase chromosome structure transition. Two scenarios of CA formation were analysed, 'static' (existing in a nucleus prior to irradiation) centres and 'dynamic' (formed in response to irradiation) centres. The modelling results reveal that under certain conditions, both scenarios explain quantitatively the dose-response relationships for both simple and complex γ-induced inter-chromosomal exchanges observed by mFISH chromosome painting in the first post-irradiation mitosis in human lymphocytes. (authors)

  6. Toward a unified approach to dose-response modeling in ecotoxicology.

    Science.gov (United States)

    Ritz, Christian

    2010-01-01

    This study reviews dose-response models that are used in ecotoxicology. The focus lies on clarification of differences and similarities between models, and as a side effect, their different guises in ecotoxicology are unravelled. A look at frequently used dose-response models reveals major discrepancies, among other things in naming conventions. Therefore, there is a need for a unified view on dose-response modeling in order to improve the understanding of it and to facilitate communication and comparison of findings across studies, thus realizing its full potential. This study attempts to establish a general framework that encompasses most dose-response models that are of interest to ecotoxicologists in practice. The framework includes commonly used models such as the log-logistic and Weibull models, but also features entire suites of models as found in various guidance documents. An outline on how the proposed framework can be implemented in statistical software systems is also provided.

  7. Equivalent dose determination in foraminifera: analytical description of the CO2--signal dose-response curve

    International Nuclear Information System (INIS)

    Hoffmann, D.; Woda, C.; Mangini, A.

    2003-01-01

    The dose-response of the CO 2 - signal (g=2.0006) in foraminifera with ages between 19 and 300 ka is investigated. The sum of two exponential saturation functions is an adequate function to describe the dose-response curve up to an additional dose of 8000 Gy. It yields excellent dating results but requires an artificial doses of at least 5000 Gy. For small additional doses of about 500 Gy the single exponential saturation function can be used to calculate a reliable equivalent dose D E , although it does not describ the dose-response for higher doses. The CO 2 - -signal dose-response indicates that the signal has two components of which one is less stable than the other

  8. Relationships Between Positive and Negative Affect and the Five Factors of Personality in a Brazilian Sample

    Directory of Open Access Journals (Sweden)

    Cristian Zanon

    2013-09-01

    Full Text Available Strong associations of Neuroticism and Extraversion with positive affects (PA and negative affects (NA have been reported in the international literature. This study aimed to evaluate the occurrence of such relationships in a Brazilian sample, and also to investigate the role of Conscientiousness, Agreeableness and Openness in the prediction of PA and NA through the use of a hybrid structural model. Participants were 319 university students, between 17 and 37 years of age (mean = 21.5, SD = 4.9. Approximately 64% of the students were female and 36% male. Results showed that Neuroticism was the most important predictor of PA and NA, followed by Conscientiousness, but not Extraversion. Surprisingly, Agreeableness was shown to be a weak prediction for NA, but had no relationship with PA. As expected, Openness showed no relationship with PA or NA. These results are partially in agreement with the international literature but some important differences were detected.

  9. Positive and Negative Aspects of Relationship Quality and Unprotected Sex among Young Women

    Science.gov (United States)

    Brady, Sonya S.; Gruber, Sandra K.; Wolfson, Julian A.

    2016-01-01

    The aim of this study was to examine both positive and negative aspects of relationship quality in relation to condom use. Sexually active young women aged 14-18 years (n = 111; 34% non-white) were recruited from community clinics and schools in the Midwest USA and provided data via an online survey. The number of unprotected sex acts in the past…

  10. Relationship of self-esteem and happiness from the positive psychology among intercultural nursing students

    OpenAIRE

    Marco Alberto Núñez Ramírez; Gloria Esthela González Quirarte; Rosario del Carmén Realpozo Reyes

    2015-01-01

    Introduction: There are contradictions on the relationship between self-esteem and happiness: it exists for some researches, for others it does not, and even some argue that self-esteem affects happiness. These variables are elementary for the practice of Nursing; however, their study is small within intercultural environments. The objective of this research is to know the association between self-esteem and happiness among Intercultural Nursing students from the positive psychology.Method: A...

  11. Dose response of alanine and methyl alanine towards gamma and in-situ alpha irradiation

    International Nuclear Information System (INIS)

    Mohapatra, M.; Rajeswari, B.; Bhide, M.K.; Rane, Vinayak; Kadam, R.M.

    2017-01-01

    In situ alpha and external gamma dose response of two ESR (electron spin resonance) dosimetric materials namely alanine and methyl alanine were investigated. It was observed that alanine dosimeter had a better dose response in comparison to methyl alanine for the in-situ alpha irradiation by using 239 Pu powder. On the other hand, in case of gamma radiation, methyl alanine was found to have the sensitivity as twice that of alanine. (author)

  12. Military Personnel: Improvements Needed to Increase Effectiveness of DOD's Programs to Promote Positive Working Relationships between Reservists and Their Employers

    National Research Council Canada - National Science Library

    Farrell, Brenda S; Schmitt, David; Anderson, Bonita; Brown, Renee; Cantin, Janine; Chatlos, Rudy; Harms, Nicole; McMurdie, Tobin; Richardson, Terry; Wallace, Shana; Williams, Tracy; Young, Matthew

    2008-01-01

    .... As demobilized reservists return to civilian life and their civilian employment, the difficulties some face in maintaining positive working relationships with their employers is an area of interest...

  13. Negative relationship behavior is more important than positive: Correlates of outcomes during stressful life events.

    Science.gov (United States)

    Rivers, Alannah Shelby; Sanford, Keith

    2018-04-01

    When people who are married or cohabiting face stressful life situations, their ability to cope may be associated with two separate dimensions of interpersonal behavior: positive and negative. These behaviors can be assessed with the Couple Resilience Inventory (CRI). It was expected that scales on this instrument would correlate with outcome variables regarding life well-being, stress, and relationship satisfaction. It was also expected that effects for negative behavior would be larger than effects for positive and that the effects might be curvilinear. Study 1 included 325 married or cohabiting people currently experiencing nonmedical major life stressors and Study 2 included 154 married or cohabiting people with current, serious medical conditions. All participants completed an online questionnaire including the CRI along with an alternate measure of couple behavior (to confirm scale validity), a measure of general coping style (to serve as a covariate), and measures of outcome variables regarding well-being, quality of life, perceived stress, and relationship satisfaction. The effects for negative behavior were larger than effects for positive in predicting most outcomes, and many effects were curvilinear. Notably, results remained significant after controlling for general coping style, and scales measuring positive and negative behavior demonstrated comparable levels of validity. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

  14. Relationship between gluteal muscle activation and upper extremity kinematics and kinetics in softball position players.

    Science.gov (United States)

    Oliver, Gretchen D

    2014-03-01

    As the biomechanical literature concerning softball pitching is evolving, there are no data to support the mechanics of softball position players. Pitching literature supports the whole kinetic chain approach including the lower extremity in proper throwing mechanics. The purpose of this project was to examine the gluteal muscle group activation patterns and their relationship with shoulder and elbow kinematics and kinetics during the overhead throwing motion of softball position players. Eighteen Division I National Collegiate Athletic Association softball players (19.2 ± 1.0 years; 68.9 ± 8.7 kg; 168.6 ± 6.6 cm) who were listed on the active playing roster volunteered. Electromyographic, kinematic, and kinetic data were collected while players caught a simulated hit or pitched ball and perform their position throw. Pearson correlation revealed a significant negative correlation between non-throwing gluteus maximus during the phase of maximum external rotation to maximum internal rotation (MIR) and elbow moments at ball release (r = -0.52). While at ball release, trunk flexion and rotation both had a positive relationship with shoulder moments at MIR (r = 0.69, r = 0.82, respectively) suggesting that the kinematic actions of the pelvis and trunk are strongly related to the actions of the shoulder during throwing.

  15. Gamma- and electron dose response of the electrical conductivity of polyaniline based polymer blends

    International Nuclear Information System (INIS)

    Sevil, U.A.; Gueven, O.; Slezsak, I.

    2002-01-01

    Complete text of publication follows. Conducting polymers, also known as 'synthetic metals' have been the subject of widespread investigations over the past decade due to their very promising characteristics. Polyaniline (PANI) holds a special position among conducting polymers in that its most highly conducting doped form can be reached by protonic acid doping or oxidative doping. It was published earlier, that the electrical conductivity of some polyaniline based polymer composites increases to a significant extent when irradiated to gamma, electron or UV radiation. The aim of the present study was to measure the high frequency conductivity of blended films of PANI with poly(vinylchloride), PVC, and chlorinated poly(propylene) irradiated in air to different doses. In order to find the most suitable composition od these composites the mass percentage of PANI within the PPCl and PVC matrix was changed between 5 - 30%. These samples were then gamma irradiated and the induced electrical conductivity was measured in the 1 kHz - 1 MHz frequency range to determine the most sensitive evaluation conditions. After selecting both the most suitable measuring conditions as well as the blend compositions the dose response of the chosen samples was determined in the dose range of 10 - 250 kGy. With respect to potential dosimetry application the effect of electron irradiation, the effect of irradiation temperature and the stability of the irradiated samples have also been investigated

  16. Understanding the relationship between religiousness, spirituality, and underage drinking: the role of positive alcohol expectancies.

    Science.gov (United States)

    Sauer-Zavala, Shannon; Burris, Jessica L; Carlson, Charles R

    2014-02-01

    Research has consistently found that religiousness and spirituality are negatively associated with underage drinking. However, there is a paucity of research exploring the mechanisms by which these variables influence this important outcome. With 344 underage young adults (ages 18-20; 61 % women), we investigated positive alcohol expectancies as a mediator between religiousness and spirituality (measured separately) and underage alcohol use. Participants completed the Religious Commitment Inventory-10, Daily Spiritual Experiences Scale, Alcohol Expectancies Questionnaire, and Drinking Styles Questionnaire. Results indicate less positive alcohol expectancies partially mediate the relationship between both religiousness and spirituality and underage alcohol use. This suggests religiousness and spirituality's protective influence on underage drinking is partly due to their influence on expectations about alcohol's positive effects. Since underage drinking predicts problem drinking later in life and places one at risk for serious physical and mental health problems, it is important to identify specific points of intervention, including expectations about alcohol that rise from religious and spiritual factors.

  17. Relationships among nocturnal jaw muscle activities, decreased esophageal pH, and sleep positions.

    Science.gov (United States)

    Miyawaki, Shouichi; Tanimoto, Yuko; Araki, Yoshiko; Katayama, Akira; Imai, Mikako; Takano-Yamamoto, Teruko

    2004-11-01

    The purpose of this study was to examine the relationships among nocturnal jaw muscle activities, decreased esophageal pH, and sleep positions. Twelve adult volunteers, including 4 bruxism patients, participated in this study. Portable pH monitoring, electromyography of the temporal muscle, and audio-video recordings were conducted during the night in the subjects' homes. Rhythmic masticatory muscle activity (RMMA) episodes were observed most frequently, with single short-burst episodes the second most frequent. The frequencies of RMMA, single short-burst, and clenching episodes were significantly higher during decreased esophageal pH episodes than those during other times. Both the electromyography and the decreased esophageal pH episodes were most frequently observed in the supine position. These results suggest that most jaw muscle activities, ie, RMMA, single short-burst, and clenching episodes, occur in relation to gastroesophageal reflux mainly in the supine position.

  18. The Relationships between Language Learning Strategies and Positive Emotions among Malaysian ESL

    Directory of Open Access Journals (Sweden)

    Mohammad Mohammadipour

    2018-01-01

    Full Text Available Emotions are an indispensable part of second language learning. The aim of this study is to determine the relationship between the use of language learning strategies and positive emotions. The present study adopted a sequential mixed methods design. The participants were 300 Malaysian ESL undergraduates selected through stratified random sampling from 5 public universities in Malaysia. The quantitative data were collected through two sets of questionnaires: (a Oxford's (1990 Strategy Inventory for Language Learning (SILL, and (b Fredrickson's (2009 modified Differential Emotional Scale (mDES. The qualitative data were gathered through semi-structured interviews. With regard to the quantitative data analysis, a series of t-tests and correlational analyses were used. The data from the interviews were analysed qualitatively. A positive significant correlation was found between positive emotions and overall language learning strategy use. Also, the qualitative results of the study indicated that the learners who experienced more positive emotions tended to use a greater variety of language learning strategies. The findings of the study emphasise the importance of students’ positive emotions in their use of language learning strategies. It might be suggested that teachers by designing the classroom settings and instructions which promote positive emotions can inspire learners to use language learning strategies more frequently and with a greater variety which in sequence relate to learners’ language learning proficiency.

  19. Positive and negative behaviours in workplace relationships: a scoping review protocol

    Science.gov (United States)

    Almost, Joan; Wolff, Angela; Mildon, Barbara; Price, Sheri; Godfrey, Christina; Robinson, Sandra; Ross-White, Amanda; Mercado-Mallari, Sheile

    2015-01-01

    Introduction Engaging in teamwork requires a clear understanding of positive and negative behaviours that act as facilitators and barriers to collegial workplace relationships. Identifying and correcting underlying barriers, while promoting facilitators, is fundamental to improving care delivery and, ultimately, clinical outcomes. Despite a considerable amount of literature in this area, there is a lack of clarity of the different behaviours as several parallel literatures address similar questions about antecedents, processes and outcomes. The purpose of this study is to synthesise the current state of literature reporting on behaviours in workplace relationships. Using a scoping review methodology, the following research question will be addressed: “What is known about positive and negative behaviours in workplace relationships?” Methods and analysis We will employ the methodological frameworks used by Arksey and O'Malley and Levac et al. The search strategy will include numerous electronic databases, grey literature sources and hand-searching of reference lists from 1990 to present with a limit to English language. Search strategies will be developed using controlled vocabulary and keyword terms related to various components of workplace relationships. Two reviewers will independently screen titles and abstracts for inclusion, followed by screening of the full text of potential articles to determine final inclusion. A descriptive numerical analysis will describe characteristics of included studies. A thematic analysis will provide an overview of the literature, including definitions, conceptual frameworks, antecedents, outcomes and interventions. Dissemination In reviewing a wide range of positive and negative behaviours, then integrating into a manageable, meaningful whole, this study is a critical step in helping policymakers, leaders and healthcare professionals effectively use what is known thus far. Knowledge translation activities will occur throughout

  20. Relationship between foramen magnum position and locomotion in extant and extinct hominoids.

    Science.gov (United States)

    Neaux, Dimitri; Bienvenu, Thibaut; Guy, Franck; Daver, Guillaume; Sansalone, Gabriele; Ledogar, Justin A; Rae, Todd C; Wroe, Stephen; Brunet, Michel

    2017-12-01

    From the Miocene Sahelanthropus tchadensis to Pleistocene Homo sapiens, hominins are characterized by a derived anterior position of the foramen magnum relative to basicranial structures. It has been previously suggested that the anterior position of the foramen magnum in hominins is related to bipedal locomotor behavior. Yet, the functional relationship between foramen magnum position and bipedal locomotion remains unclear. Recent studies, using ratios based on cranial linear measurements, have found a link between the anterior position of the foramen magnum and bipedalism in several mammalian clades: marsupials, rodents, and primates. In the present study, we compute these ratios in a sample including a more comprehensive dataset of extant hominoids and fossil hominins. First, we verify if the values of ratios can distinguish extant humans from apes. Then, we test whether extinct hominins can be distinguished from non-bipedal extant hominoids. Finally, we assess if the studied ratios are effective predictors of bipedal behavior by testing if they mainly relate to variation in foramen magnum position rather than changes in other cranial structures. Our results confirm that the ratios discriminate between extant bipeds and non-bipeds. However, the only ratio clearly discriminating between fossil hominins and other extant apes is that which only includes basicranial structures. We show that a large proportion of the interspecific variation in the other ratios relates to changes in facial, rather than basicranial, structures. In this context, we advocate the use of measurements based only on basicranial structures when assessing the relationship between foramen magnum position and bipedalism in future studies. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. [Brazilian teenagers and beer advertising: relationship between exposure, positive response, and alcohol consumption].

    Science.gov (United States)

    Vendrame, Alan; Pinsky, Ilana; Faria, Roberta; Silva, Rebeca

    2009-02-01

    Brazilian teenagers report problematic patterns of alcohol consumption. Alcohol advertising strategies are one of the main factors influencing adolescents' alcohol consumption. The aim of this study was to evaluate the relationship between positive responses to TV beer commercials, exposure, and alcohol consumption. Thirty-two recent TV commercials were shown to 133 high school students from public schools in São Bernardo do Campo, São Paulo State, Brazil. The subjects recorded how well they liked the ads and how often they had already watched each commercial. The teenagers also reported their alcohol consumption rates. The ten commercials analyzed in this article were the five most popular and the five least popular. The analysis showed that subjects had already seen the five most popular ads, but not the five least popular. In addition, the five most popular ads received higher scores from teenagers that reported having consumed beer during the previous month. The study found a positive relationship between enjoying beer advertising and exposure to beer ads, as well as between alcohol consumption and positive responses to alcohol commercials.

  2. EARLY POSTPARTUM PARENTAL PREOCCUPATION AND POSITIVE PARENTING THOUGHTS: RELATIONSHIP WITH PARENT-INFANT INTERACTION.

    Science.gov (United States)

    Kim, Pilyoung; Mayes, Linda; Feldman, Ruth; Leckman, James F; Swain, James E

    2013-01-01

    Parenting behaviors and parent-infant emotional bonding during the early postpartum months play a critical role in infant development. However, the nature and progression of parental thoughts and their relationship with interactive behaviors have received less research. The current study investigated the trajectory of parental thoughts and behaviors among primiparous mothers ( n = 18) and fathers ( n = 15) and multiparous mothers ( n = 13) and fathers ( n = 13), which were measured at the first and third postpartum month. At the third postpartum month, the relationship between parental thoughts and parental interactive behaviors also was tested. Mothers and fathers showed high levels of preoccupations and caregiving thoughts during the first postpartum month that significantly declined by the third postpartum month. In contrast, positive thoughts about parenting and the infant increased over the same time interval. Mothers presented higher levels of preoccupations and positive thoughts than did fathers, and first-time parents reported more intense preoccupations than did experienced parents. Although maternal sensitivity was inversely related to maternal anxious thoughts, paternal sensitivity was predicted by higher levels of anxious as well as caregiving and positive thoughts.

  3. Application of Key Events Dose Response Framework to defining the upper intake level of leucine in young men.

    Science.gov (United States)

    Pencharz, Paul B; Russell, Robert M

    2012-12-01

    Leucine is sold in large doses in health food stores and is ingested by weight-training athletes. The safety of ingestion of large doses of leucine is unknown. Before designing chronic high-dose leucine supplementation experiments, we decided to determine the effect of graded doses of leucine in healthy participants. The Key Events Dose Response Framework is an organizational and analytical framework that dissects the various biologic steps (key events) that occur between exposure to a substance and an eventual adverse effect. Each biologic event is looked at for its unique dose-response characteristics. For nutrients, there are a number of biologic homeostatic mechanisms that work to keep circulating/tissue levels in a safe, nontoxic range. If a response mechanism at a particular key event is especially vulnerable and easily overwhelmed, this is known as a determining event, because this event drives the overall slope or shape of the dose-response relationship. In this paper, the Key Events Dose Framework has been applied to the problem of leucine toxicity and leucine's tolerable upper level. After analyzing the experimental data vis a vis key events for leucine leading to toxicity, it became evident that the rate of leucine oxidation was the determining event. A dose-response study has been conducted to graded intakes of leucine in healthy human adult male volunteers. All participants were started at the mean requirement level of leucine [50 mg/(kg · d)] and the highest leucine intake was 1250 mg/( kg · d), which is 25 times the mean requirement. No gut intolerance was seen. Blood glucose fell progressively but remained within normal values without any changes in plasma insulin. Maximal leucine oxidation levels occurred at an intake of 550 mg leucine/( kg · d), after which plasma leucine progressively increased and plasma ammonia also increased in response to leucine intakes >500 mg/( kg · d). Thus, the "key determining event" appears to be when the

  4. The relationship between skin manifestations and CD4 counts among hiv positive patients

    International Nuclear Information System (INIS)

    Rad, F.; Ghaderi, E.; Moradi, G.; Mafakheri, L.

    2008-01-01

    Skin manifestations are common clinical features among HIV positive patients. The aim of this study was to document skin manifestations and their relationships with CD4 cell counts among HIV positive patients in Sanandaj. This was a descriptive study. The patients were examined for skin disorders by a dermatologist and CD4 counts were obtained from the patient's medical records. Independent samples T test were used for data analysis. In this study 66 (94.3%) patients had at least one skin problem. Fungal infections were the most common cause. The eight most common types of mucocutaneous problems were gingivitis, pallor, itching, photosensitivity, seborrheic dermatitis, candidiasis, folliculitis and tinea versicolor. The most common manifestation was gingivitis. Mean CD4 cell counts were lower in individuals with viral and bacterial skin diseases (P <0.05). The results of this study indicated that skin problems were common among HIV positive patients. Patients with advanced stages of skin disorders had relatively lower CD4 counts. Therefore examination of skin is recommended for all HIV positive patients for early detection of skin disorders, as early diagnosis and management of dermatologic problems will improve the quality of life in HIV positive patients. (author)

  5. Dose-response meta-analysis on coffee, tea and caffeine consumption with risk of Parkinson's disease.

    Science.gov (United States)

    Qi, Hui; Li, Shixue

    2014-04-01

    A dose-response meta-analysis was carried out between Parkinson's disease (PD) risk, and coffee, tea and caffeine consumption. A comprehensive search was carried out to identify eligible studies. The fixed or random effect model was used based on heterogeneity test. The dose-response relationship was assessed by restricted cubic spline. A total of 13 articles involving 901 764 participants for coffee, eight articles involving 344 895 participants for tea and seven articles involving 492 724 participants for caffeine were included. A non-linear relationship was found between coffee consumption and PD risk overall, and the strength of protection reached the maximum at approximately 3 cups/day (smoking-adjusted relative risk: 0.72, 95% confidence interval 0.65-0.81). A linear relationship was found between tea and caffeine consumption, and PD risk overall, and the smoking-adjusted risk of PD decreased by 26% and 17% for every two cups/day and 200 mg/day increments, respectively. The association of coffee and tea consumption with PD risk was stronger for men than that for women, and the association of caffeine consumption with PD risk was stronger for ever users of hormones than that for never users of hormones among postmenopausal women. The aforementioned associations were weaker for USA relative to Europe or Asia. A linear dose-relationship for decreased PD risk with tea and caffeine consumption was found, whereas the strength of protection reached a maximum at approximately 3 cups/day for coffee consumption overall. Further studies are required to confirm the findings. © 2013 Japan Geriatrics Society.

  6. 混合舒芬太尼时布比卡因用于剖宫产术重度子痫前期患者蛛网膜下腔阻滞的量效关系%Dose-response relationship of bupivacaine coadministered with sufentanil for subarachnoid block in severely preeclamptic patients undergoing cesarean delivery

    Institute of Scientific and Technical Information of China (English)

    肖飞; 徐文平; 刘林; 常向阳; 张引法; 王立中

    2016-01-01

    Objective To determine the dose⁃response relationship of bupivacaine coadministered with sufentanil for subarachnoid block in severely preeclamptic patients undergoing cesarean delivery. Methods Two hundred patients with severe preeclampsia, of American Society of Anesthesiologists physi⁃cal statusⅠ⁃Ⅲ, scheduled for elective cesarean delivery, were divided into 4 groups ( n=50 each) using a random number table: bupivacaine 4 mg group ( group B4 ) , bupivacaine 6 mg group ( group B6 ) , bupivacaine 8 mg group ( group B8 ) , and bupivacaine 10 mg group ( group B10 ) . In B4 , B6 , B8 and B10 groups, bupivacaine 4, 6, 8 and 10 mg plus 2.5μg sufentanil in 2.5 ml of normal saline were injected into the subarachnoid space, respectively. Effective anesthesia was defined as bilateral sensory block of T6 achieved at 10 min after intrathecal administration when measured by pin⁃prick test, and with no need for epidural supplementation ( lidocaine ) . A probit analysis was used to estimate the 50% effective dose ( ED50 ) and 95% effective dose ( ED95 ) with 95% confidence intervals for bupivacaine, coadministered with sufentanil, when used for subarachnoid block in severely preeclamptic patients underwent cesarean de⁃livery. Results When coadministered with sufentanil, the ED50 and ED95 ( 95% confidence interval) of bupivacaine were 5.67 ( 5. 20-6. 10) mg and 8. 82 ( 8. 14-9.87) mg, respectively, for subarachnoid block in severely preeclamptic patients underwent cesarean delivery. Conclusion The ED50 and ED95 of bupivacaine for subarachnoid block, when coadministered with sufentanil 2.5 μg, are 5.67 and 8.82 mg, respectively, in severely preeclamptic patients undergoing cesarean delivery.%目的:确定混合舒芬太尼时布比卡因用于剖宫产术重度子痫前期患者蛛网膜下腔阻滞的量效关系。方法选择行剖宫产术的重度子痫前期患者200例,ASA分级Ⅰ⁃Ⅲ级,采用随机数字表法分为4组( n=50

  7. Radiation dose response simulation for biomechanical-based deformable image registration of head and neck cancer treatment

    International Nuclear Information System (INIS)

    Al-Mayah, Adil; Moseley, Joanne; Hunter, Shannon; Brock, Kristy

    2015-01-01

    Biomechanical-based deformable image registration is conducted on the head and neck region. Patient specific 3D finite element models consisting of parotid glands (PG), submandibular glands (SG), tumor, vertebrae (VB), mandible, and external body are used to register pre-treatment MRI to post-treatment MR images to model the dose response using image data of five patients. The images are registered using combinations of vertebrae and mandible alignments, and surface projection of the external body as boundary conditions. In addition, the dose response is simulated by applying a new loading technique in the form of a dose-induced shrinkage using the dose-volume relationship. The dose-induced load is applied as dose-induced shrinkage of the tumor and four salivary glands. The Dice Similarity Coefficient (DSC) is calculated for the four salivary glands, and tumor to calculate the volume overlap of the structures after deformable registration. A substantial improvement in the registration is found by including the dose-induced shrinkage. The greatest registration improvement is found in the four glands where the average DSC increases from 0.53, 0.55, 0.32, and 0.37 to 0.68, 0.68, 0.51, and 0.49 in the left PG, right PG, left SG, and right SG, respectively by using bony alignment of vertebrae and mandible (M), body (B) surface projection and dose (D) (VB+M+B+D). (paper)

  8. Coffee consumption and mortality from all causes, cardiovascular disease, and cancer: a dose-response meta-analysis.

    Science.gov (United States)

    Crippa, Alessio; Discacciati, Andrea; Larsson, Susanna C; Wolk, Alicja; Orsini, Nicola

    2014-10-15

    Several studies have analyzed the relationship between coffee consumption and mortality, but the shape of the association remains unclear. We conducted a dose-response meta-analysis of prospective studies to examine the dose-response associations between coffee consumption and mortality from all causes, cardiovascular disease (CVD), and all cancers. Pertinent studies, published between 1966 and 2013, were identified by searching PubMed and by reviewing the reference lists of the selected articles. Prospective studies in which investigators reported relative risks of mortality from all causes, CVD, and all cancers for 3 or more categories of coffee consumption were eligible. Results from individual studies were pooled using a random-effects model. Twenty-one prospective studies, with 121,915 deaths and 997,464 participants, met the inclusion criteria. There was strong evidence of nonlinear associations between coffee consumption and mortality for all causes and CVD (P for nonlinearity Coffee consumption was not associated with cancer mortality. Findings from this meta-analysis indicate that coffee consumption is inversely associated with all-cause and CVD mortality. © The Author 2014. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  9. Study on the dose response characteristics of a scanning liquid ion-chamber electronic portal imaging device

    CERN Document Server

    Ma Shao Gang; Song Yi Xin

    2002-01-01

    Objective: To study the dose response characteristics and the influence factors such as gantry angle, field size and acquisition mode on the dosimetric response curves, when using a scanning liquid ion-chamber electronic portal imaging device (EPID) for dose verification. Methods: All experiments were carried out on a Varian 600 C/D accelerator (6 MV X-ray) equipped with a Varian PortalVision sup T sup M MK2 type EPID. To obtain the dose response curve, the relationship between the incident radiation intensity to the detector and the pixel value output from the EPID were established. Firstly, the different dose rates of 6 MV X-rays were obtained by varying SSD. Secondly, three digital portal images were acquired for each dose rate using the EPID and averaged to avoid the influence of the dose rate fluctuations of the accelerator. The pixel values of all images were read using self-designed image analysis software, and and average for a region consisting of 11 x 11 pixels around the center was taken as the res...

  10. Investigation of vacuum pumping on the dose response of the MAGAS normoxic polymer gel dosimeter

    International Nuclear Information System (INIS)

    Venning, AJ.; Canberra Hospital, Canberra; University of Sydney, Sydney; Mather, ML.; Baldock, C.

    2005-01-01

    The effect of vacuum pumping on the dose response of the MAGAS polymer gel dosimeter has been investigated. A delay of several days post-manufacture before irradiation was previously necessary due to the slow oxygen scavenging of ascorbic acid. The MAGAS polymer gel dosimeter was vacuum pumped before gelation to remove dissolved oxygen. The MAGAS polymer gel dosimeter was poured into glass screw-top vials, which were irradiated at various times, post-manufacture to a range of doses. Magnetic resonance imaging techniques were used to determine the R2-dose response and /?2-dose sensitivity of the MAGAS polymer gel. The results were compared with a control batch of MAGAS polymer gel that was not vacuum pumped. It was shown that vacuum pumping on the MAGAS polymer gel solution immediately prior to sealing in glass screw-top vials initially increases the R2-dose response and R2-dose sensitivity of the dosimeter. An increase in the .R2-dose response and i?2-dose sensitivity was observed with increasing time between manufacture and irradiation. Over the range of post-manufacture irradiation times investigated, the greatest i?2-dose response and if 2 -dose sensitivity occurred at 96 hours

  11. The relationship between personalities and self-report positive driving behavior in a Chinese sample

    Science.gov (United States)

    Sun, Xianghong; Zhang, Kan

    2018-01-01

    Driving behaviors play an important role in accident involvement. Concretely speaking, aberrant driving behaviors would cause more accidents, and oppositely positive driving behaviors would promote to build safety traffic environment. The main goals of this study were to explore the positive driving behavior and its relationship with personality in a Chinese sample. A total of 421 licensed drivers (286 male and 135 female) from Beijing, China completed the Positive Driver Behavior Scale (PDBS), the Driver Behavior Questionnaire (DBQ), the Dula Dangerous Driving Index (DDDI) and the Big Five Inventory (BFI) on a voluntary and anonymous basis. The results showed that the Chinese version of the PDBS has both reliability and validity and that the PDBS was significantly correlated with the BFI. Specifically, the PDBS was negatively correlated with neuroticism (r = -0.38) and positively correlated with extraversion, agreeableness, conscientiousness and openness to experience (the correlation coefficient ranged from 0.36 to 0.55). In contrast with previous research, age was negatively correlated with the PDBS (r = -0.38) in our sample, which may have resulted from less driving experience or a lack of available cognitive resources. PMID:29324823

  12. Relationship of self-esteem and happiness from the positive psychology among intercultural nursing students

    Directory of Open Access Journals (Sweden)

    Marco Alberto Núñez Ramírez

    2015-07-01

    Full Text Available Introduction: There are contradictions on the relationship between self-esteem and happiness: it exists for some researches, for others it does not, and even some argue that self-esteem affects happiness. These variables are elementary for the practice of Nursing; however, their study is small within intercultural environments. The objective of this research is to know the association between self-esteem and happiness among Intercultural Nursing students from the positive psychology.Method: A quantitative, descriptive, transversal and correlational, research with a non-experimental design was realized, with a sample of 55 students of Intercultural Nursing. Two questionnaires were applied: the scale of Rosenberg self-esteem and happiness of Lima scale.Results: High levels of self-esteem and happiness were obtained. Through correlation of Pearson and hierarchical regression we found that self-esteem is associated in negative and positive way with certain factors of happiness; the same thing happened in the level of influence.Conclusion: In positive psychology is possible to associate variables such as self-esteem and happiness as strengths. Much more in the case of Intercultural Nursing students which have the aim to contribute to the indigenous communities development, that require nurses with favorable levels of self-esteem and the perception of subjective well-being to counteract an historical legacy of backwardness. From positive psychology is possible that this educational model will contribute to the mutual enrichment and empowerment within the work of the Intercultural Nursing.

  13. The relationship between personalities and self-report positive driving behavior in a Chinese sample.

    Directory of Open Access Journals (Sweden)

    Biying Shen

    Full Text Available Driving behaviors play an important role in accident involvement. Concretely speaking, aberrant driving behaviors would cause more accidents, and oppositely positive driving behaviors would promote to build safety traffic environment. The main goals of this study were to explore the positive driving behavior and its relationship with personality in a Chinese sample. A total of 421 licensed drivers (286 male and 135 female from Beijing, China completed the Positive Driver Behavior Scale (PDBS, the Driver Behavior Questionnaire (DBQ, the Dula Dangerous Driving Index (DDDI and the Big Five Inventory (BFI on a voluntary and anonymous basis. The results showed that the Chinese version of the PDBS has both reliability and validity and that the PDBS was significantly correlated with the BFI. Specifically, the PDBS was negatively correlated with neuroticism (r = -0.38 and positively correlated with extraversion, agreeableness, conscientiousness and openness to experience (the correlation coefficient ranged from 0.36 to 0.55. In contrast with previous research, age was negatively correlated with the PDBS (r = -0.38 in our sample, which may have resulted from less driving experience or a lack of available cognitive resources.

  14. The relationship between personalities and self-report positive driving behavior in a Chinese sample.

    Science.gov (United States)

    Shen, Biying; Qu, Weina; Ge, Yan; Sun, Xianghong; Zhang, Kan

    2018-01-01

    Driving behaviors play an important role in accident involvement. Concretely speaking, aberrant driving behaviors would cause more accidents, and oppositely positive driving behaviors would promote to build safety traffic environment. The main goals of this study were to explore the positive driving behavior and its relationship with personality in a Chinese sample. A total of 421 licensed drivers (286 male and 135 female) from Beijing, China completed the Positive Driver Behavior Scale (PDBS), the Driver Behavior Questionnaire (DBQ), the Dula Dangerous Driving Index (DDDI) and the Big Five Inventory (BFI) on a voluntary and anonymous basis. The results showed that the Chinese version of the PDBS has both reliability and validity and that the PDBS was significantly correlated with the BFI. Specifically, the PDBS was negatively correlated with neuroticism (r = -0.38) and positively correlated with extraversion, agreeableness, conscientiousness and openness to experience (the correlation coefficient ranged from 0.36 to 0.55). In contrast with previous research, age was negatively correlated with the PDBS (r = -0.38) in our sample, which may have resulted from less driving experience or a lack of available cognitive resources.

  15. Digitoxin medication and cancer; case control and internal dose-response studies

    Directory of Open Access Journals (Sweden)

    Spigset Olav

    2001-08-01

    Full Text Available Abstract Background Digitoxin induces apoptosis in different human malignant cell lines in vitro. In this paper we investigated if patients taking digitoxin for cardiac disease have a different cancer incidence compared to the general population. Methods Computer stored data on digitoxin concentrations in plasma from 9271 patients with cardiac disease were used to define a user population. Age and sex matched controls from the Norwegian Cancer Registry were used to calculate the number of expected cancer cases. Results The population on digitoxin showed a higher incidence of cancer compared to the control population. However, an additional analysis showed that the population on digitoxin had a general increased risk of cancer already, before the start on digitoxin. Leukemia/lymphoma were the cancer types which stood out with the highest risk in the digitoxin population before starting on digitoxin. This indicates that yet unknown risk factors exist for cardiovascular disease and lymphoproliferative cancer. An internal dose-response analysis revealed a relationship between high plasma concentration of digitoxin and a lower risk for leukemia/lymphoma and for cancer of the kidney/urinary tract. Conclusion Morbidity and mortality are high in the population on digitoxin, due to high age and cardiac disease.These factors disturb efforts to isolate an eventual anticancer effect of digitoxin in this setting. Still, the results may indicate an anticancer effect of digitoxin for leukemia/lymphoma and kidney/urinary tract cancers. Prospective clinical cancer trials have to be done to find out if digitoxin and other cardiac glycosides are useful as anticancer agents.

  16. Albumin treatment regimen for type 1 hepatorenal syndrome: a dose-response meta-analysis.

    Science.gov (United States)

    Salerno, Francesco; Navickis, Roberta J; Wilkes, Mahlon M

    2015-11-25

    Recommended treatment for type 1 hepatorenal syndrome consists of albumin and vasoconstrictor. The optimal albumin dose remains poorly characterized. This meta-analysis aimed to determine the impact of albumin dose on treatment outcomes. Clinical studies of type 1 hepatorenal syndrome treatment with albumin and vasoconstrictor were sought. Search terms included: hepatorenal syndrome; albumin; vasoconstrictor; terlipressin; midodrine; octreotide; noradrenaline; and norepinephrine. A meta-analysis was performed of hepatorenal syndrome reversal and survival in relation to albumin dose. Nineteen clinical studies with 574 total patients were included, comprising 8 randomized controlled trials, 8 prospective studies and 3 retrospective studies. The pooled percentage of patients achieving hepatorenal syndrome reversal was 49.5% (95% confidence interval, 40.0-59.1%). Increments of 100 g in cumulative albumin dose were accompanied by significantly increased survival (hazard ratio, 1.15; 95% confidence interval, 1.02-1.31; p = 0.023). A non-significant increase of similar magnitude in hepatorenal syndrome reversal was also observed (odds ratio, 1.15; 95% confidence interval, 0.97-1.37; p = 0.10). Expected survival rates at 30 days among patients receiving cumulative albumin doses of 200, 400 and 600 g were 43.2% (95% confidence interval, 36.4-51.3%), 51.4% (95% confidence interval, 46.3-57.1%) and 59.0% (95% confidence interval, 51.9-67.2), respectively. Neither survival nor hepatorenal syndrome reversal was significantly affected by vasoconstrictor dose or type, treatment duration, age, baseline serum creatinine, bilirubin or albumin, baseline mean arterial pressure, or study design, size or time period. This meta-analysis suggests a dose-response relationship between infused albumin and survival in patients with type 1 hepatorenal syndrome. The meta-analysis provides the best current evidence on the potential role of albumin dose selection in improving outcomes of

  17. Liposomal bupivacaine as a single-injection peripheral nerve block: a dose-response study.

    Science.gov (United States)

    Ilfeld, Brian M; Malhotra, Nisha; Furnish, Timothy J; Donohue, Michael C; Madison, Sarah J

    2013-11-01

    Currently available local anesthetics approved for single-injection peripheral nerve blocks have a maximum duration of fashion. The end points included the maximum voluntary isometric contraction (MVIC) of the quadriceps femoris muscle and tolerance to cutaneous electrical current in the femoral nerve distribution. Measurements were performed from baseline until quadriceps MVIC returned to 80% of baseline bilaterally. There were statistically significant dose responses in MVIC (0.09%/mg, SE = 0.03, 95% confidence interval [CI], 0.04-0.14, P = 0.002) and tolerance to cutaneous current (-0.03 mA/mg, SE = 0.01, 95% CI, -0.04 to -0.02, P 40 mg, tolerance to cutaneous current did not return to within 20% above baseline until after 24 hours in 100% of subjects (95% CI, 56%-100%). MVIC did not consistently return to within 20% of baseline until after 24 hours in 90% of subjects (95% CI, 54%-100%). Motor block duration was not correlated with bupivacaine dose (0.06 hour/mg, SE = 0.14, 95% CI, -0.27 to 0.39, P = 0.707). The results of this investigation suggest that deposition of a liposomal bupivacaine formulation adjacent to the femoral nerve results in a partial sensory and motor block of >24 hours for the highest doses examined. However, the high variability of block magnitude among subjects and inverse relationship of dose and response magnitude attests to the need for a phase 3 study with a far larger sample size, and that these results should be viewed as suggestive, requiring confirmation in a future trial.

  18. Influence of Exercise Intensity for Improving Depressed Mood in Depression: A Dose-Response Study.

    Science.gov (United States)

    Meyer, Jacob D; Koltyn, Kelli F; Stegner, Aaron J; Kim, Jee-Seon; Cook, Dane B

    2016-07-01

    Exercise effectively improves mood in major depressive disorder (MDD), but the optimal exercise stimulus to improve depressed mood is unknown. To determine the dose-response relationship of acute exercise intensity with depressed mood responses to exercise in MDD. We hypothesized that the acute response to exercise would differ between light, moderate, and hard intensity exercise with higher intensities yielding more beneficial responses. Once weekly, 24 women (age: 38.6±14.0) diagnosed with MDD underwent a 30-minute session at one of three steady-state exercise intensities (light, moderate, hard; rating of perceived exertion 11, 13 or 15) or quiet rest on a stationary bicycle. Depressed mood was evaluated with the Profile of Mood States before, 10 and 30 minutes post-exercise. Exercise reduced depressed mood 10 and 30 minutes following exercise, but this effect was not influenced by exercise intensity. Participants not currently taking antidepressants (n=10) had higher baseline depression scores, but did not demonstrate a different antidepressant response to exercise compared to those taking antidepressants. To acutely improve depressed mood, exercise of any intensity significantly improved feelings of depression with no differential effect following light, moderate, or hard exercise. Pharmacological antidepressant usage did not limit the mood-enhancing effect of acute exercise. Acute exercise should be used as a symptom management tool to improve mood in depression, with even light exercise an effective recommendation. These results need to be replicated and extended to other components of exercise prescription (e.g., duration, frequency, mode) to optimize exercise guidelines for improving depression. Copyright © 2016. Published by Elsevier Ltd.

  19. Religiousness, well-being and ageing – selected explanations of positive relationships

    Directory of Open Access Journals (Sweden)

    Woźniak Barbara

    2015-12-01

    Full Text Available According to research that have been conducted in the field of gerontology, sociology and psychology of ageing, there is a relationship between the level of religious involvement and health status/ well-being/quality of life in older age. How does religiousness influence aging process and health status? The aim of the article is to review explanations of a positive relationship between religiousness and health that are discussed in the literature. Those explanations may be grouped in three broad categories reflecting three functions of religion that play a role for well-being in older age. Those functions are: (1 religiousness as a source of coherence and the role of religious coping and provision of meaning in dealing with stressful life events (including ageing losses (2 religiousness as a source of positive self-perception and a sense of personal control, (3 provision of social resources (i.e. social ties and social support within religious community and emphasis on interpersonal relations (with special focus on forgiveness as a norm in interpersonal relations. Those functions of religion are discussed in the context of their potential role in successful ageing, as determined by - among others - active engagement in life.

  20. Positive Institutions and their relationship with transformational leadership, empathy and team performance

    Directory of Open Access Journals (Sweden)

    Jessica Solares Menegazzo

    2015-09-01

    Full Text Available The current study tests the relationship between transformational leadership, empathy and excellent team performance, based on the HEalthy & Resilient Organizations (HERO Model (Salanova, Llorens, Cifre & Martínez, 2012 in positive institutions, the third pillar of positive psychology (Seligman & Csikszentmihalyi, 2000. The study of empathy and its role in companies is important because it is not yet widely known the benefits that can provide to any institution. The study attempt to show a full mediating role of empathy in this relationship. The sample consist on  69 work teams, from 7 Small -and Medium- sized Enterprises (SMEs including 4 educational institutions and 3 institutions of medical services from Spain. The Interclass Correlation Coefficients (ICC1 and ICC2 and the Average Deviation Index (ADM(J supports data aggregation at the team level. The results using SEM, through work teams, supported the hypothesis, that is, the empathy plays a full mediating role between transformational leadership and excellent team performance. Finally, theoretical and practical implications of the results are discussed.

  1. Parent-child relationships and offspring's positive mental wellbeing from adolescence to early older age.

    Science.gov (United States)

    Stafford, Mai; Kuh, Diana L; Gale, Catharine R; Mishra, Gita; Richards, Marcus

    2016-05-03

    We examined parent-child relationship quality and positive mental well-being using Medical Research Council National Survey of Health and Development data. Well-being was measured at ages 13-15 (teacher-rated happiness), 36 (life satisfaction), 43 (satisfaction with home and family life) and 60-64 years (Diener Satisfaction With Life scale and Warwick Edinburgh Mental Well-being scale). The Parental Bonding Instrument captured perceived care and control from the father and mother to age 16, recalled by study members at age 43. Greater well-being was seen for offspring with higher combined parental care and lower combined parental psychological control ( p  < 0.05 at all ages). Controlling for maternal care and paternal and maternal behavioural and psychological control, childhood social class, parental separation, mother's neuroticism and study member's personality, higher well-being was consistently related to paternal care. This suggests that both mother-child and father-child relationships may have short and long-term consequences for positive mental well-being.

  2. Dose-response association between leisure time physical activity and work ability: Cross-sectional study among 3000 workers.

    Science.gov (United States)

    Calatayud, Joaquin; Jakobsen, Markus D; Sundstrup, Emil; Casaña, Jose; Andersen, Lars L

    2015-12-01

    Regular physical activity is important for longevity and health, but knowledge about the optimal dose of physical activity for maintaining good work ability is unknown. This study investigates the association between intensity and duration of physical activity during leisure time and work ability in relation to physical demands of the job. From the 2010 round of the Danish Work Environment Cohort Study, currently employed wage earners with physically demanding work (n = 2952) replied to questions about work, lifestyle and health. Excellent (100 points), very good (75 points), good (50 points), fair (25 points) and poor (0 points) work ability in relation to the physical demands of the job was experienced by 18%, 40%, 30%, 10% and 2% of the respondents, respectively. General linear models that controlled for gender, age, physical and psychosocial work factors, lifestyle and chronic disease showed that the duration of high-intensity physical activity during leisure was positively associated with work ability, in a dose-response fashion (p performing ⩾ 5 hours of high-intensity physical activity per week had on average 8 points higher work ability than those not performing such activities. The duration of low-intensity leisure-time physical activity was not associated with work ability (p = 0.5668). The duration of high-intensity physical activity during leisure time is associated in a dose-response fashion with work ability, in workers with physically demanding jobs. © 2015 the Nordic Societies of Public Health.

  3. Physical Activity and Motor Competence Present a Positive Reciprocal Longitudinal Relationship Across Childhood and Early Adolescence.

    Science.gov (United States)

    Lima, Rodrigo A; Pfeiffer, Karin; Larsen, Lisbeth R; Bugge, Anna; Moller, Niels C; Anderson, Lars B; Stodden, David F

    2017-06-01

    The current study evaluated the reciprocal longitudinal relationship between physical activity (PA) and motor competence (MC) and the potential mediation of cardiorespiratory endurance across 7 years. This was a 7-year longitudinal study, the Copenhagen School Child Intervention Study (CoSCIS), with 3 measuring points [mean ages (in years) and respective sample size: 6.75 ± 0.37, n = 696; 9.59 ± 1.07, n = 617; 13.35 ± 0.34, n = 513]. PA was assessed using accelerometers. MC was evaluated by the Körperkoordinationstest für Kinder (KTK) test battery. Cardiorespiratory fitness (VO 2 peak) was evaluated using a continuous running protocol until exhaustion. Structural equation modeling was performed to evaluate the longitudinal associations. Vigorous PA (VPA) and MC presented reciprocal longitudinal association during the 7-year follow-up (VPA → MC; β = 0.18; 95% CI: 0.10, 0.26; MC → VPA; β = 0.14; 95% CI: 0.08, 0.21). In addition, VO 2 peak mediated the relationship in both directions (VPA → MC; β = 0.09; 95% CI: 0.06, 0.12; MC → VPA; β = 0.06; 95% CI: 0.03, 0.09). PA and MC presented a positive reciprocal relationship across childhood through early adolescence and VO 2 peak mediated the association in both directions. Interventions targeting to increase PA in children and adolescents should also address the development of MC skills because of the clear positive feedback loop between PA and MC.

  4. Dose-response relationship of cadmium or radiation-induced embryotoxicity in mouse whole embryo culture

    International Nuclear Information System (INIS)

    Nakashima, Kiyohito; Kawamata, Akitoshi; Matsuoka, Masato; Wakisaka, Takashi; Fujiki, Yoshishige

    1988-01-01

    Mouse embryos of B6C3F 1 strain were exposed in vitro to 1.2 to 2.2 μM cadmium chloride (Cd) or to 100 to 320 R x-rays, and the effects of the exposure on development were examined after 39 h of culture. Development of embryos was assessed from lethality, formation of the neural tube defect, diameter and protein of yolk sac, crown-rump and head lengths, embryonic protein, and number of somites. Incidence of the neural tube defect increased from 3.4 to 100% by 1.2 to 2.0 μM Cd, while embryo deaths increased from 13.8 to 93.3% by 2.0 to 2.2 μM Cd. Embryonic protein was significantly reduced at the teratogenic range, but the number of somites was only affected by 1.6 to 2.0 μM Cd. X-irradiation at 100 to 320 R induced the neural tube defect in 2.9 to 72.7% of the embryos. An embryolethal effect was observed only at the 320 R dose. Crown-rump and head lengths and embryonic protein were significantly affected at the teratogenic range, but the diameter and protein of yolk sac and number of somites were hardly affected. Cadmium- or radiation-induced response data of both teratogenicity and endpoints indicating inhibition of embryonic development were acceptably fitted to a linear log-probit regression. These regressions suggest that as an estimation of interference in development of embryos, embryonic protein and head length are sensitive endpoints while the number of somites is an insensitive criterion. (author)

  5. Fertility of Tall Girls Treated with High-Dose Estrogen, a Dose-Response Relationship

    NARCIS (Netherlands)

    Hendriks, A. E. J.; Drop, S. L. S.; Laven, J. S. E.; Boot, A. M.

    Context: High-dose estrogen treatment to reduce final height of tall girls increases their risk for infertility in later life. Objective: The aim was to study the effect of estrogen dose on fertility outcome of these women. Design/Setting: We conducted a retrospective cohort study of university

  6. Dose-response relationships for bone tumors in beagles exposed to 226Ra and 90Sr

    International Nuclear Information System (INIS)

    Raabe, O.G.; Parks, N.J.; Book, S.A.

    1981-01-01

    385 dogs were exposed to 90 Sr in food from mid-gestation to 540 days of age. 243 young adult dogs were given eight fortnightly injections of 226 Ra. Comparison was made with available mouse and human 226 Ra bone tumor data. The major findings were: a) the occurrence of bone tumor related deaths was much less for 90 Sr than for 226 Ra exposed dogs. b) RBE for bone tumors from 90 Sr-Y varied as a function of average dose rate to bone. c) people require 10 times as long as mice and 3.6 times as long as dogs to develop 226 Ra-induced bone tumors at a given skeletal dose rate. d) based on the results, a practical threshold for bone cancer from 226 Ra was estimated to exist at cumulative doses of about 50-110 rad for dogs, mice and people. (author)

  7. Dose-response relationships of clothianidin, imidacloprid, and thiamethoxam to Blissus occiduus (Hemiptera: Blissidae).

    Science.gov (United States)

    Stamm, M D; Baxendale, F P; Heng-Moss, T M; Siegfried, B D; Blankenship, E E; Gaussoin, R E

    2011-02-01

    The western chinch bug, Blissus occiduus Barber (Hemiptera: Blissidae), has emerged as a serious pest of buffalograss, Buchlod dactyloides (Nuttall) Engelmann. In general, neonicotinoid insecticides effectively control a variety of turfgrass insects, particularly phloem-feeding pests. However, because of well documented inconsistencies in control, these compounds are generally not recommended for chinch bugs. This study was designed to document the contact and systemic toxicity of three neonicotinoid insecticides (clothianidin, imidacloprid, and thiamethoxam) to B. occiduus. In contact bioassays, thiamethoxam was approximately 20-fold less toxic than clothianidin or imidacloprid to B. occiduus nymphs and three-fold more toxic to adults. In adult systemic bioassays, thiamethoxam was up to five-fold more toxic than clothianidin or imidacloprid. Interestingly, thiamethoxam was significantly more toxic to adults than to nymphs in both contact and systemic bioassays. This was not observed with clothianidin or imidacloprid. Bifenthrin, used for comparative purposes, exhibited 1844-fold and 122-fold increase in toxicity to nymphs and adults, respectively. These results provide the first documentation of the relative toxicity of these neonicotinoid insecticides to B. occiduus.

  8. Dose-response relationship of rat aryl hydrocarbon hydroxylase and epoxide hydratase induction

    Energy Technology Data Exchange (ETDEWEB)

    Gielen, J.E.; Goujon, F.M.; Sele-Doyen, J.; Van Cantfort, J.

    1980-01-01

    This paper summarizes our recent results supporting the hypothesis that different regulation mechanisms are involved in the control of AHH and EH activity and that the AHH induction in the extrahepatic tissues might also be affected by liver specific inducers. In the rat, lung and kidney AHH is highly sensitive to the inducers present in cigarette smoke and cigarette smoke condensate, the EH activity not being affected by the same agents. Phenobarbital is also able to protentiate the inducing action of low doses of benzo(a)pyrene on the lung AHH activity. In primary rat liver cells in culture, AHH and EH can be selectivly induced. Low doses of benz(a)anthracene preferentially enhance the AHH activity while trans-stilbene oxide an various antioxidants modify only the EH activity. Phenobarbital, which also induces the AHH activity in cell culture, produces a more than additive effect when added to the culture medium in a mixture with benz(a)anthracene. Trans-stilbene oxide prevents the AHH induction by phenobarbital and not by benz(a)anthracene. Our results suggest that, in addition to its own induction capacity, phenobarbital is also able to potentiate the action of chemicals belonging to a different class of inducers.

  9. The scientific basis for the establishment of threshold levels and dose response relationships of carcinogenesis

    International Nuclear Information System (INIS)

    1975-01-01

    Over the last one and a half decades the variety of radiosterilized articles has increased to such an extent that it is almost impossible to present a complete list. They include disposable surgical and medical instruments and devices, laboratory equipment, sutures and other temporary and permanent implants, medicaments and pharmaceutical starting materials, biological tissues for transplantation and other biological preparations. A large volume of radiation-sterilized hermetically sealed, ready-to-use medical supplies are imported by many non-producer countries to supplement their public health care services. During the recent years this trend is increasing and several developing countries are even planning to introduce this technology in the near future, while some have already done so through the provision of expertise and funding by the IAEA and UNDP. Unlike the technologically advanced countries, the medical care services in most of the developing countries are inadequate still today. Against the figure of one doctor per 500 people in the most highly advanced countries the corresponding figure in some developing countries stands as one doctor per 60,000 people. The available limited number of hospitals in many such countries are located only in the urban areas, while the preponderance of rural populations are served through non-equipped mobile dispensaries and camp health centres. Based upon these factors, many developing countries are opting to introduce the technology and practices of radiation sterilization of medical products even if the products cost slightly more. During the last ten years the Agency's programme has attached great importance to encouraging this development of peaceful application of atomic energy in the form of accumulation of relevant technical information through co-ordinated research and its early dissemination by holding international meetings. The Agency's second symposium on Ionizing Radiation for Sterilization of Medical Products and Biological Tissues was held in Bombay, India, in December 1974, to summarize and critically review all the current information and experiences on the practices including the regulatory aspects of the processes involved as well as the safety assurance of the final products. The topics of discussion during the symposium were carried out under the following sessions: (i) Microbiological control aspects of radiation sterilization (ii) Dosimetry aspects of radiation sterilization (iii) Effects of sterilizing radiation dose on the constituents of medical products (iv) Application of radiation sterilization on medical products of biological origin (v) Application on Pharmaceuticals (vi) Technological aspects of radiation sterilization facilities (vii) Review of the current status of radiation sterilization of medical products in the developing and developed Member States. mportant considerations on the microbiological control aspects of radiation sterilization focussed on the role of pre-sterilization contamination levels, radio-resistance of the contaminants, choice of sterilizing radiation dose, the use of standardized microbiological indicators, and the feasibility of combination radiation treatments with heat and hydrostatic pressure. The data were presented in support of the model for application of sub-sterilizing radiation dose in the routine control and safety assurance determination for medical products. The practical dosimetry systems for the process calibration and control were evaluated as supported by the data from the various national experiences. Suitability of application of radiation sterilization method for the Pharmaceuticals and biological tissue preparations were reviewed. esigning and operations of radiation sterilization facilities in keeping with the conditions (market size, nature of products and volume, available technical expertise) of the developing countries were discussed and appropriate steps recommended. ince its inception the radiation-sterilized medical supplies have increasingly been introduced in the markets of the countrie s beyond their national boundary of manufacturing. An early acceptance of such products of public health significance continue to rely on the international standardization of the partices concerned. Agency's document on the Recommended Practice for Radiation Sterilization of Medical Products was discussed and reviewed by the participants in order to revise and up-date in the light of the current experiences. The Recommendations continue to serve as a guide in the formulation of the national standards and specifications by the Member States. (author)

  10. Dose-response relationship of sertindole and haloperidol using the pharmacopsychometric triangle

    DEFF Research Database (Denmark)

    Bech, P; Tanghøj, P; Andreasson, K

    2011-01-01

    Renewed insight into dose-related effects of sertindole and haloperidol was sought by re-analysing published data for antipsychotic effect, extrapyramidal effect, and patient wellbeing - i.e., the important pharmacopsychometric triangle domains.......Renewed insight into dose-related effects of sertindole and haloperidol was sought by re-analysing published data for antipsychotic effect, extrapyramidal effect, and patient wellbeing - i.e., the important pharmacopsychometric triangle domains....

  11. Dose-response relationships between four pesticides and phosphorus uptake by hyphae of arbuscular mycorrhizas

    DEFF Research Database (Denmark)

    Schweiger, P.F.; Jakobsen, I.

    1998-01-01

    The effect of the fungicides carbendazim, fenpropimorph and propiconazole and of the insecticide dimethoate on plant P uptake via external hyphae of arbuscular mycorrhizal (AM) fungi was examined. Mycorrhizal plants were grown in a two-compartment system where a root-free hyphal compartment...... was separated from the main root compartment by nylon mesh. After 5 weeks of plant growth external hyphae of the AM fungi had spread throughout the hyphal compartment. At this time aqueous solutions of both P-32 and pesticide were added to the hyphal compartment. Resulting soil pesticide concentrations covered...

  12. In vitro study of dose-response relationship of fluoride with dental enamel

    Directory of Open Access Journals (Sweden)

    Arthur, Rodrigo Alex et al.

    2007-01-01

    Full Text Available Modelos in vitro para avaliação da reatividade do fluoreto (F devem apresentar resposta dose-efeito. Dessa forma, o objetivo desse estudo foi avaliar a relação dose-resposta do fluoreto presente em solução aquosa com o esmalte dental bovino. Cento e vinte blocos de esmalte bovino (5 × 5 × 2 mm, 60 hígidos e 60 com lesão artificial de cárie, foram submetidos durante 10 minutos à água destilada e deionizada (controle negativo e soluções aquosas contendo 50, 100, 200 ou 400 µg F/mL. Cada grupo experimental recebeu 12 blocos hígidos e 12 blocos com lesão artificial de cárie. Duas camadas consecutivas de esmalte dental foram removidas de todos os blocos dentais por meio de ataque ácido e o fluoreto extraído foi determinado com eletrodo específico. Os resultados de fluoreto incorporado foram expressos em µg por g de esmalte removido, considerando a quantidade total das duas camadas. A incorporação de fluoreto pelo esmalte hígido mostrou uma relação dose-resposta linear (p = 0,0001, enquanto que os blocos com lesão de cárie mostraram relação polinomial quadrática (p < 0,0001. Os resultados sugerem que o modelo in vitro de reatividade empregado no presente estudo é apropriado para avaliar a relação doseresposta entre o fluoreto em solução aquosa e aquele incorporado pelo esmalte dental bovino hígido ou com lesão artificial de cárie.

  13. Ozone dose-response relationships for spring oilseed rape and broccoli

    Science.gov (United States)

    De Bock, Maarten; Op de Beeck, Maarten; De Temmerman, Ludwig; Guisez, Yves; Ceulemans, Reinhart; Vandermeiren, Karine

    2011-03-01

    Tropospheric ozone is an important air pollutant with known detrimental effects for several crops. Ozone effects on seed yield, oil percentage, oil yield and 1000 seed weight were examined for spring oilseed rape ( Brassica napus cv. Ability). For broccoli ( Brassica oleracea L. cv. Italica cv. Monaco) the effects on fresh marketable weight and total dry weight were studied. Current ozone levels were compared with an increase of 20 and 40 ppb during 8 h per day, over the entire growing season. Oilseed rape seed yield was negatively correlated with ozone dose indices calculated from emergence until harvest. This resulted in an R2 of 0.24 and 0.26 ( p broccoli the applied ozone doses had no effect on yield.

  14. Bermudagrass (Cynodon spp) dose-response relationships with clethodim, glufosinate and glyphosate.

    Science.gov (United States)

    Webster, Theodore M; Hanna, Wayne W; Mullinix, Benjamin G

    2004-12-01

    Greenhouse studies were conducted to evaluate the sensitivity of three commercial cultivars, eight experimental cultivars and common bermudagrass to clethodim, glufosinate and glyphosate. Each herbicide was applied at eight doses. Data were regressed on herbicide dose using a log-logistic curve (R2 = 0.56-0.95 for clethodim, R2 = 0.60-0.94 for glufosinate, and R2 = 0.70-0.96 for glyphosate). The herbicide rate that elicited a 50% plant response (I50) in the bermudagrass cultivars ranged from 0.04 to 0.19 kg ha(-1) clethodim, 0.19 to 1.33 kg ha(-1) glufosinate and 0.34 to 1.14 kg ha(-1) glyphosate. Relative to other cultivars, common bermudagrass was intermediate in its response to clethodim and among the most tolerant cultivars to glufosinate and glyphosate. TifSport was relatively tolerant to clethodim and glufosinate compared with other cultivars, but relatively sensitive to glyphosate. One cultivar, 94-437, was consistently among the most sensitive cultivars to each of the herbicides. While there were differential herbicide tolerances among the tested bermudagrass cultivars, there did not appear to be any naturally occurring herbicide resistance that could be commercially utilized. However, research indicated that breeding efforts should target herbicide resistance that is at least four times the registered use rate. Also, TifSport and Tifway have been identified as suitable representatives of triploid hybrid bermudagrass cultivars to be used to evaluate the success of turfgrass renovation programs. 2004 Society of Chemical Industry.

  15. Non-Linear Dose-Response Relationships in Biology, Toxicology and Medicine - An International Conference

    Energy Technology Data Exchange (ETDEWEB)

    Calabrese, Edward J.; Kostecki, Paul T.

    2002-05-28

    Conference abstract book contains seven sections: Plenary-4 abstracts; Chemical-9 abstracts; Radiation-7 abstracts; Ultra Low Doses and Medicine-6 abstracts; Biomedical-11 abstracts; Risk Assessment-5 abstracts and Poster Sessions-25 abstracts. Each abstract was provided by the author/presenter participating in the conference.

  16. Dose-response relationship between antimicrobial drugs and livestock-associated MRSA in pig farming

    NARCIS (Netherlands)

    Dorado-García, Alejandro; Dohmen, Wietske; Bos, M.E.H.; Verstappen, K.M.; Houben, Manon; Wagenaar, J.A.; Heederik, D.J.J.

    2015-01-01

    The farming community can be a vehicle for introduction of livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) in hospitals. During 2011–2013, an 18-month longitudinal study aimed at reducing the prevalence of LA-MRSA was conducted on 36 pig farms in the Netherlands.

  17. Pregabalin versus gabapentin in partial epilepsy: a meta-analysis of dose-response relationships

    Directory of Open Access Journals (Sweden)

    Thompson Sally

    2010-11-01

    Full Text Available Abstract Background To compare the efficacy of pregabalin and gabapentin at comparable effective dose levels in patients with refractory partial epilepsy. Methods Eight randomized placebo controlled trials investigating the efficacy of pregabalin (4 studies and gabapentin (4 studies over 12 weeks were identified with a systematic literature search. The endpoints of interest were "responder rate" (where response was defined as at least a 50% reduction from baseline in the number of seizures and "change from baseline in seizure-free days over the last 28 days (SFD". Results of all trials were analyzed using an indirect comparison approach with placebo as the common comparator. The base-case analysis used the intention-to-treat last observation carried forward method. Two sensitivity analyses were conducted among completer and responder populations. Results The base-case analysis revealed statistically significant differences in response rate in favor of pregabalin 300 mg versus gabapentin 1200 mg (odds ratio, 1.82; 95% confidence interval, 1.02, 3.25 and pregabalin 600 mg versus gabapentin 1800 mg (odds ratio, 2.52; 95% confidence interval, 1.21, 5.27. Both sensitivity analyses supported the findings of the base-case analysis, although statistical significance was not demonstrated. All dose levels of pregabalin (150 mg to 600 mg were more efficacious than corresponding dosages of gabapentin (900 mg to 2400 mg in terms of SFD over the last 28 days. Conclusion In patients with refractory partial epilepsy, pregabalin is likely to be more effective than gabapentin at comparable effective doses, based on clinical response and the number of SFD.

  18. Negative Thinking versus Positive Thinking in a Singaporean Student Sample: Relationships with Psychological Well-Being and Psychological Maladjustment

    Science.gov (United States)

    Wong, Shyh Shin

    2012-01-01

    This study examines the relationships of positive thinking versus negative thinking with psychological well-being and psychological maladjustment. Three hundred and ninety-eight undergraduate students from Singapore participated in this study. First, positive thinking were positively correlated with indicators psychological well-being--life…

  19. The Relationships Between Positive-Negative Affectivity and Individual-Organizational Level Aggressiveness: The Role of Physical Activity

    Directory of Open Access Journals (Sweden)

    Mahmut ÖZDEVECİOĞLU

    2013-06-01

    Full Text Available The main aim of the present study is to find out the relationships between, positive and negative affectivity, physical activity, personal level aggressiveness - organization level aggressiveness and mediation effect of physical activity. The universe of the research is employees of Kayseri Organized Industrial Zone businesses in which physical activity is done. The size of the research is 273. According to the results, there is a significant and negative oriented relationship between positive affectivity and individual level aggressiveness. There is a significant and positive oriented relationship between negative affectivity and individual level aggressiveness. There is a significant and positive oriented relationship between positive affectivity and physical activity. There is a significant and negative oriented relationship between negative affectivity and physical activity. There is a significant and negative oriented relationship between physical activity and individual level aggressiveness. There is a significant and positive oriented relationship between individual level aggressiveness and organization level aggressiveness. Separately physical activity has a significant mediation role between positive-negative affectivity and individual level aggressiveness.

  20. Intracoronary irradiation: dose response for the prevention of restenosis in swine

    International Nuclear Information System (INIS)

    Weinberger, Judah; Amols, Howard; Ennis, Ronald D.; Schwartz, Allan; Wiedermann, Joseph G.; Marboe, Charles

    1996-01-01

    Purpose: Restenosis after percutaneous transluminal coronary angioplasty represents, in part, a proliferative response of vascular smooth muscle at the site of injury. We have previously shown that high-dose radiation (20 Gy), delivered via an intracoronary 192 Ir source, causes focal medial fibrosis and markedly impairs the restenosis process after balloon angioplasty in swine. This study sought to delineate the dose-response characteristics of this effect. Methods and Materials: Forty juvenile swine underwent coronary angiography; a segment of the left coronary artery was chosen as a target for balloon injury. In 30 swine, a 2 cm ribbon of 192 Ir was positioned at the target segment and 20, 15, or 10 Gy were delivered to the vessel wall (10 animals/dose). Subsequently, overdilatation balloon angioplasty was performed at the irradiated segment. In 10 control swine, overdilatation balloon angioplasty was performed without previous irradiation. Thirty-eight animals survived until sacrifice at 30 ± 3 days. Histopathological analysis was performed by a pathologist in a blinded manner. The area of maximal luminal compromise within the target segment was analyzed via computer-assisted planimetry. Results: Neointimal area was decreased by 71.4% at 20 Gy and by 58.3% at 15 Gy compared with control animals (p < 0.05 for both). A stimulatory effect on smooth muscle cell proliferation was noted at 10 Gy, with a 123% increase in neointimal area compared with controls (p < 0.05). Mean percent area stenosis was also reduced by 63% at 20 Gy and by 74.8% at 15 Gy compared with controls (p < 0.05 for both). Conclusions: Intracoronary irradiation prior to overstretch balloon angioplasty markedly reduces neointima formation; this effect is dose dependent, with evidence of a significant stimulatory effect at 10 Gy. The effective therapeutic dose range for the prevention of restenosis in this model begins at approximately 15 Gy delivered to the vessel wall

  1. Relationship between the position of upper and lower incisors and the internal structure of symphysis

    International Nuclear Information System (INIS)

    Suzuki, Kayou; Nishide, Masashi; Ishii, Yasumasa; Enomoto, Yutaka; Kawamura, Akira; Kasai, Kazutaka

    2002-01-01

    The aim of this study was to investigate the relationship between the position of the upper and lower incisors and cortical bone thickness and CT value of mandibular symphysis obtained by CT images and cephalograms. The specimens were 24 dry skulls of mordern Japanese males (mean age 29 years) without marked crowding and missing tooth, which had been preserved in the Tokyou University Museum. The data were transferred to a workstation, and CT value and thickness of cortical bone were measured. The dentofacial morphology was investigated with a lateral cephalogram. The results were as follows; The thickness of cortal bone was more thicker in order of basal, lingual and labial cortical bone. The CT value showed the same tendency as cortical bone thickness. Significant correlation coefficients were found between cortical bone thickness and CT value in 30, 60, 90, 120 degree areas. The inclination of upper incisors was negatively related to the CT value in basal and lingual region of symphysis. The inclination of lower incisors was positively related to the CT value in basal and lingual region of symphysis. The interincisor angle was positively related to the CT value in basal region of symphysis. In conclusion, the results of this study suggested that the labio-lingual inclination of the upper and lower incisors was associated with the CT value of basal region of sysphysis. It is suggested that the internal structures of symphysis which relate to the occlusion types of incisors are affected by function of masticatory muscles. (author)

  2. A positive relationship between spring temperature and productivity in 20 songbird species in the boreal zone.

    Science.gov (United States)

    Meller, Kalle; Piha, Markus; Vähätalo, Anssi V; Lehikoinen, Aleksi

    2018-03-01

    Anthropogenic climate warming has already affected the population dynamics of numerous species and is predicted to do so also in the future. To predict the effects of climate change, it is important to know whether productivity is linked to temperature, and whether species' traits affect responses to climate change. To address these objectives, we analysed monitoring data from the Finnish constant effort site ringing scheme collected in 1987-2013 for 20 common songbird species together with climatic data. Warm spring temperature had a positive linear relationship with productivity across the community of 20 species independent of species' traits (realized thermal niche or migration behaviour), suggesting that even the warmest spring temperatures remained below the thermal optimum for reproduction, possibly due to our boreal study area being closer to the cold edge of all study species' distributions. The result also suggests a lack of mismatch between the timing of breeding and peak availability of invertebrate food of the study species. Productivity was positively related to annual growth rates in long-distance migrants, but not in short-distance migrants. Across the 27-year study period, temporal trends in productivity were mostly absent. The population sizes of species with colder thermal niches had decreasing trends, which were not related to temperature responses or temporal trends in productivity. The positive connection between spring temperature and productivity suggests that climate warming has potential to increase the productivity in bird species in the boreal zone, at least in the short term.

  3. Dose-response evaluation after Yttrium-90 resin microsphere radio-embolization of breast cancer liver metastases

    International Nuclear Information System (INIS)

    Gnesin, S.; Verdun, F.R.; Baechler, S.; Boubacker, A.; Adib, S.; Cherbuin, N.; Prior, J.O.; Bize, P.; Denys, A.

    2015-01-01

    Full text of publication follows. Aim: Yttrium-90 resin microsphere radio-embolization is a valuable therapeutic option in metastatic breast cancer patients with progressive disease refractory to chemotherapy. The goal of this study was to evaluate the dose-response relationship of liver metastasis based on a 3D voxelized 90 Y PET dosimetry. Materials and methods: we studied the dose-response relationship of twelve hepatic lesions in four selected patients with metastatic breast cancer who underwent 90 Y radio-embolization (Sirtex SIR-Spheres Pty Ltd.). The administered activity ranged from 1 to 1.3 GBq. Ten days before treatment, patients underwent a baseline 18 F-FDG PET/CT. The determination of the 90 Y-microsphere activity to administer for treatment was based on the BSA method refined with the partition model derived from a 99m Tc-MAA SPECT/CT performed a week prior to radio-embolization. Within 24 hours after treatment, 90 Y TOF PET/CT imaging was performed. A follow-up 18 F-FDG PET/CT was performed 1 month after the treatment to evaluate the response to radio-embolization. For each patient, 3D voxelized dose-maps were obtained from the post-treatment 90 Y TOF PET/CT. A volume of interest (VOI) was drawn for each selected hepatic lesion using the baseline 18 F-FDG PET/CT. To obtain dose-volume histogram (DVH) for each lesion, image co-registration and VOI masks were generated using the PMOD 3.4 software and then exported in Matlab for dose calculation. Furthermore, the average absorbed dose in lesions was corrected for PVE effects by multiplication for appropriate (phantom-based) recovery coefficients according to the lesion size. Early metabolic lesion response was assessed in terms of variation in the maximum standard uptake value (ΔSUVmax) between baseline and follow-up 18 F-FDG PET/CT. The average absorbed dose for each lesion was associated with the respective metabolic response. Results: for the 12 selected lesions, the average volume was 35 cm 3

  4. [Relationship between the prone position and achieving head control at 3 months].

    Science.gov (United States)

    Pérez-Machado, J L; Rodríguez-Fuentes, G

    2013-10-01

    Owing to the significant increase of mild motor delays and the strong intolerance of infants to be placed on prone position observed in the Physiotherapy Unit of the Maternal and Children's University Hospital of the Canaries (HUMIC), a study was conducted to determine whether positioning infants in the prone position while awake affected the achievement and quality of head control at three months. A prospective comparative practice-based study of a representative sample of 67 healthy infants born in the HUMIC, and divided into an experimental group (n = 35) and control group (n = 32). The Alberta Infant Motor Scale (AIMS) and a parent questionnaire were used as measurement tools. The intervention consisted of regular home visits to the experimental group (from the first to the third month). The two groups were evaluated in their homes at the end of 3 months. The differences in mean raw score of the AIMS at 3 months were, 16.26 in the experimental group and 10.38 in control group (P<.001). The percentile mean was 94 in the experimental group, and less than 50 (42) in the control group. All of the experimental group babies achieved the head control, with only 8 in the control group (25%). The significant findings suggest a direct relationship between the time spent in the prone position when the baby is awake and the achievement of head control at three months. Copyright © 2012 Asociación Española de Pediatría. Published by Elsevier Espana. All rights reserved.

  5. Dose-response study of the hematological toxicity induced by vectorized radionuclides in a mouse model

    International Nuclear Information System (INIS)

    Rousseau-Poivet, J.; Sas, N.; Nguyen, F.; Abadie, J.; Chouin, N.; Barbet, J.

    2015-01-01

    studied progenitor and blood cells. As compared to 0.8 Gy, one more week was necessary at 1.4 Gy. A mild anemia (21% erythrocyte depletion) was noticed only at this higher absorbed dose between D3 and D10. Conclusion: absorbed doses to the BM between 0.8 and 1.4 Gy induced hematological toxicity expressed by transient BM aplasia, neutropenia, thrombocytopenia and inconsistent anemia. These depletions and time to recovery were both dose-dependent. Higher absorbed doses will be achieved to better investigate the dose-response relationship and to further develop our compartmental model for platelets. Neutrophils and erythrocytes kinetics are also under investigation to generate satisfying simulations with the model. (authors)

  6. Circle Solutions, a philosophy and pedagogy for learning positive relationships: What promotes and inhibits sustainable outcomes?

    Directory of Open Access Journals (Sweden)

    Florence McCarthy

    2013-04-01

    Full Text Available Educators are increasingly aware that the efficacy of social and emotional learning (SEL is dependent on implementation factors, not just program content. These include the philosophy underpinning an intervention, the beliefs as well as the skills of facilitators, and the classroom/whole school context in which the intervention takes place. This article outlines the philosophy and pedagogy of Circle Solutions and presents findings from research where 18 undergraduate students supported and developed ‘Circle Time’ in 8 Greater Western Sydney primary schools for a university module on community service. The study indicates that when there is full teacher participation within the principles of the Circle philosophy, together with activeschool support that promotes relational values, the learning outcomes for positive relationship building are more sustainable.

  7. 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.

  8. Modeling and regression analysis of semiochemical dose-response curves of insect antennal reception and behavior

    Science.gov (United States)

    Dose-response curves with semiochemicals are reported in many articles in insect chemical ecology regarding neurophysiology and behavioral bioassays. Most such curves are shown in figures where the x-axis has order of magnitude increases in dosages versus responses on the y-axis represented by point...

  9. Dose-response relations for stricture in the proximal oesophagus from head and neck radiotherapy

    International Nuclear Information System (INIS)

    Alevronta, Eleftheria; Ahlberg, Alexander; Mavroidis, Panayiotis; Al-Abany, Massoud; Friesland, Signe; Tilikidis, Aris; Laurell, Goeran; Lind, Bengt K.

    2010-01-01

    Background and purpose: Determination of the dose-response relations for oesophageal stricture after radiotherapy of the head and neck. Material and methods: In this study 33 patients who developed oesophageal stricture and 39 patients as controls are included. The patients received radiation therapy for head and neck cancer at Karolinska University Hospital, Stockholm, Sweden. For each patient the 3D dose distribution delivered to the upper 5 cm of the oesophagus was analysed. The analysis was conducted for two periods, 1992-2000 and 2001-2005, due to the different irradiation techniques used. The fitting has been done using the relative seriality model. Results: For the treatment period 1992-2005, the mean doses were 49.8 and 33.4 Gy, respectively, for the cases and the controls. For the period 1992-2000, the mean doses for the cases and the controls were 49.9 and 45.9 Gy and for the period 2001-2005 were 49.8 and 21.4 Gy. For the period 2001-2005 the best estimates of the dose-response parameters are D 50 = 61.5 Gy (52.9-84.9 Gy), γ = 1.4 (0.8-2.6) and s = 0.1 (0.01-0.3). Conclusions: Radiation-induced strictures were found to have a dose response relation and volume dependence (low relative seriality) for the treatment period 2001-2005. However, no dose response relation was found for the complete material.

  10. Cytogenetics dosimetry: dose-response curve for low doses of X-ray

    International Nuclear Information System (INIS)

    Lara, Virginia E. Noval; Pineda Bolivar, William R.; Riano, Victor M. Pabon; Ureana, Cecilia Crane

    2013-01-01

    The purpose of this study was to conduct a preliminary study for the standardization in the future, the dose-response curve for low doses of X-rays, through the analysis of in vitro cultures of peripheral blood samples of 3 men and 3 women occupationally not exposed to artificial sources of ionizing radiation, age 18-40 years, where possible nonsmokers

  11. Guidelines for Use of the Approximate Beta-Poisson Dose-Response Model.

    Science.gov (United States)

    Xie, Gang; Roiko, Anne; Stratton, Helen; Lemckert, Charles; Dunn, Peter K; Mengersen, Kerrie

    2017-07-01

    For dose-response analysis in quantitative microbial risk assessment (QMRA), the exact beta-Poisson model is a two-parameter mechanistic dose-response model with parameters α>0 and β>0, which involves the Kummer confluent hypergeometric function. Evaluation of a hypergeometric function is a computational challenge. Denoting PI(d) as the probability of infection at a given mean dose d, the widely used dose-response model PI(d)=1-(1+dβ)-α is an approximate formula for the exact beta-Poisson model. Notwithstanding the required conditions α1, issues related to the validity and approximation accuracy of this approximate formula have remained largely ignored in practice, partly because these conditions are too general to provide clear guidance. Consequently, this study proposes a probability measure Pr(0 (22α̂)0.50 for 0.020.99) . This validity measure and rule of thumb were validated by application to all the completed beta-Poisson models (related to 85 data sets) from the QMRA community portal (QMRA Wiki). The results showed that the higher the probability Pr(0 Poisson model dose-response curve. © 2016 Society for Risk Analysis.

  12. Dose response association of pregnancy cigarette smoke exposure, childhood stature, overweight and obesity

    NARCIS (Netherlands)

    Koshy, Gibby; Delpisheh, Ali; Brabin, Bernard J.

    2011-01-01

    The combined dose response effects of pregnancy cigarette smoke exposure on childhood overweight, obesity and short stature have not been reported. A community based cross-sectional survey of 3038 children aged 5-11 years from 15 primary schools in Merseyside, UK. Self-completed parental

  13. Pharmacogenetic Predictors of Methylphenidate Dose-Response in Attention-Deficit/Hyperactivity Disorder

    Science.gov (United States)

    Froehlich, Tanya E.; Epstein, Jeffery N.; Nick, Todd G.; Melguizo Castro, Maria S.; Stein, Mark A.; Brinkman, William B.; Graham, Amanda J.; Langberg, Joshua M.; Kahn, Robert S.

    2011-01-01

    Objective: Because of significant individual variability in attention-deficit/hyperactivity disorder (ADHD) medication response, there is increasing interest in identifying genetic predictors of treatment effects. This study examined the role of four catecholamine-related candidate genes in moderating methylphenidate (MPH) dose-response. Method:…

  14. IsoGeneGUI : Multiple approaches for dose-response analysis of microarray data using R

    NARCIS (Netherlands)

    Otava, Martin; Sengupta, Rudradev; Shkedy, Ziv; Lin, Dan; Pramana, Setia; Verbeke, Tobias; Haldermans, Philippe; Hothorn, Ludwig A.; Gerhard, Daniel; Kuiper, Rebecca M.; Klinglmueller, Florian; Kasim, Adetayo

    2017-01-01

    The analysis of transcriptomic experiments with ordered covariates, such as dose-response data, has become a central topic in bioinformatics, in particular in omics studies. Consequently, multiple R packages on CRAN and Bioconductor are designed to analyse microarray data from various perspectives

  15. QUANTITATION OF MOLECULAR ENDPOINTS FOR THE DOSE-RESPONSE COMPONENT OF CANCER RISK ASSESSMENT

    Science.gov (United States)

    Cancer risk assessment involves the steps of hazard identification, dose-response assessment, exposure assessment and risk characterization. The rapid advances in the use of molecular biology approaches has had an impact on all four components, but the greatest overall current...

  16. Dose Response Effects of Lisdexamfetamine Dimesylate Treatment in Adults with ADHD: An Exploratory Study

    Science.gov (United States)

    Faraone, Stephen V.; Spencer, Thomas J.; Kollins, Scott H.; Glatt, Stephen J.; Goodman, David

    2012-01-01

    Objective: To explore dose-response effects of lisdexamfetamine dimesylate (LDX) treatment for ADHD. Method: This was a 4-week, randomized, double-blinded, placebo-controlled, parallel-group, forced-dose titration study in adult participants, aged 18 to 55 years, meeting "Diagnostic and Statistical Manual of Mental Disorders" (4th ed., text rev.)…

  17. Dose-Response Effect of Sunlight on Vitamin D2 Production in Agaricus bisporus Mushrooms

    DEFF Research Database (Denmark)

    Urbain, Paul; Jakobsen, Jette

    2015-01-01

    The dose response effect of UV-B irradiation from sunlight on vitamin D2 content of sliced Agaricus bisporus (white button mushroom) during the process of sun-drying was investigated.Real-time UV-B and UV-A data were obtained using a high-performance spectroradiometer. During the first hour...

  18. Beginning and experienced secondary school teachers' self- and student schema in positive and problematic teacher-student relationships

    NARCIS (Netherlands)

    Claessens, Luce|info:eu-repo/dai/nl/357401530; van Tartwijk, Jan|info:eu-repo/dai/nl/112629385; Pennings, Heleen|info:eu-repo/dai/nl/323242588; van der Want, Anna; Verloop, Nico; den Brok, Perry; Wubbels, Theo|info:eu-repo/dai/nl/070651361

    2016-01-01

    The quality of teacher-student relationships is important for teachers' well-being in schools. In this interview study we investigated which cognitions comprise secondary school teachers' self- and student schema in positive and problematic teacher-student relationships. Frequency analyses of these

  19. Positive Outcome Expectancy Mediates the Relationship Between Peer Influence and Internet Gaming Addiction Among Adolescents in Taiwan.

    Science.gov (United States)

    Wu, Jo Yung Wei; Ko, Huei-Chen; Wong, Tsui-Yin; Wu, Li-An; Oei, Tian Po

    2016-01-01

    The present study examined the role of positive outcome expectancy in the relationship between peer/parental influence and Internet gaming addiction (IGA) among adolescents in Taiwan. Two thousand, one hundred and four junior high students completed the Chen Internet Addiction Scale for IGA, Parental Influence for IGA, peer influence for IGA, and Positive Outcome Expectancy of Internet Gaming Questionnaire. Results showed that the three types of peer influences (positive attitudes toward Internet gaming, frequency of Internet game use, and invitation to play) and positive outcome expectancy were significantly and positively correlated with IGA. Moreover, peer influence was also positively correlated with positive outcome expectancy. On the other hand, positive outcome expectancy and parental influences had a low correlation. Structural equation modeling analysis revealed that positive outcome expectancy did not mediate the relationship between either type of parental influences and IGA, and only the parent's invitation to play Internet games directly predicted IGA severity. However, peers' positive attitude or the frequency of peers' Internet game use positively predicted IGA and was fully mediated through positive outcome expectancy of Internet gaming. In addition, the frequency of peers' invitation to play Internet games directly and indirectly predicted IGA severity through a partial mediation of positive outcome expectancy of Internet gaming. The overall fit of the model was adequate and was able to explain 25.0 percent of the variance. The findings provide evidence in illuminating the role of peer influences and positive outcome expectancy of Internet gaming in the process of why adolescents may develop IGA.

  20. Personality and emotional processing: A relationship between extraversion and the late positive potential in adolescence.

    Science.gov (United States)

    Speed, Brittany C; Nelson, Brady D; Perlman, Greg; Klein, Daniel N; Kotov, Roman; Hajcak, Greg

    2015-08-01

    Neuroticism and extraversion are multifaceted affective-laden personality traits that have been associated with major depressive disorder (MDD). Research and theory have argued that extraversion, and particularly its facet positive emotionality, is specific to MDD, while neuroticism is common across internalizing disorders. Converging evidence has suggested that MDD is associated with reduced engagement with emotional stimuli, but it remains unclear whether either extraversion, neuroticism, or both modulate reactivity to emotional cues. The late positive potential (LPP) is an event-related brain potential that is uniquely suited to assess engagement with emotional stimuli because it reflects sustained attention toward emotional content. The current study examined the LPP in relation to personality traits that may confer risk for depression by examining the relationship between the LPP and both neuroticism and extraversion in never-depressed adolescent girls. Specifically, 550 girls aged 13.5-15.5 with no lifetime history of depression completed an emotional picture-viewing task, and the LPP was measured in response to neutral, pleasant, and unpleasant pictures. Personality traits were gathered via self- and informant report. Results indicated that high extraversion was associated with a potentiated LPP to emotional pictures-and this effect was accounted for by positive emotionality in particular. In contrast, there was no association between the LPP and neuroticism or its facets. The present study is one of the first to demonstrate that extraversion is associated with variation in neural indices of emotional picture processing, similar to what has been observed among individuals with depression and at high risk for depression. © 2015 Society for Psychophysiological Research.

  1. Dose-response study of thimerosal-induced murine systemic autoimmunity

    International Nuclear Information System (INIS)

    Havarinasab, S.; Lambertsson, L.; Qvarnstroem, J.; Hultman, P.

    2004-01-01

    The organic compound ethylmercurithiosalicylate (thimerosal), which is primarily present in the tissues as ethylmercury, has caused illness and several deaths due to erroneous handling when used as a disinfectant or as a preservative in medical preparations. Lately, possible health effects of thimerosal in childhood vaccines have been much discussed. Thimerosal is a well-known sensitizing agent, although usually of no clinical relevance. In rare cases, thimerosal has caused systemic immune reactions including acrodynia. We have studied if thimerosal might induce the systemic autoimmune condition observed in genetically susceptible mice after exposure to inorganic mercury. A.SW mice were exposed to 1.25-40 mg thimerosal/l drinking water for 70 days. Antinucleolar antibodies, targeting the 34-kDa protein fibrillarin, developed in a dose-related pattern and first appeared after 10 days in the two highest dose groups. The lowest observed adverse effect level (LOAEL) for antifibrillarin antibodies was 2.5 mg thimerosal/l, corresponding to an absorbed dose of 147 μg Hg/kg bw and a concentration of 21 and 1.9 μg Hg/g in the kidney and lymph nodes, respectively. The same LOAEL was found for tissue immune-complex deposits. The total serum concentration of IgE, IgG1, and IgG2a showed a significant dose-related increase in thimerosal-treated mice, with a LOAEL of 5 mg thimerosal/l for IgG1 and IgE, and 20 mg thimerosal/l for IgG2a. The polyclonal B-cell activation showed a significant dose-response relationship with a LOAEL of 10 mg thimerosal/l. Therefore, thimerosal induces in genetically susceptible mice a systemic autoimmune syndrome very similar to that seen after treatment with inorganic mercury, although a higher absorbed dose of Hg is needed using thimerosal. The autoimmune syndrome induced by thimerosal is different from the weaker and more restricted autoimmune reaction observed after treatment with an equipotent dose of methylmercury

  2. Dose-Response of High-Intensity Training (HIT on Atheroprotective miRNA-126 Levels

    Directory of Open Access Journals (Sweden)

    Boris Schmitz

    2017-05-01

    Full Text Available Aim: MicroRNA-126 (miR-126 exerts beneficial effects on vascular integrity, angiogenesis, and atherosclerotic plaque stability. The purpose of this investigation was to analyze the dose-response relationship of high-intensity interval training (HIIT on miR-126-3p and -5p levels.Methods: Sixty-one moderately trained individuals (females = 31 [50.8%]; 22.0 ± 1.84 years were consecutively recruited and allocated into three matched groups using exercise capacity. During a 4-week intervention a HIIT group performed three exercise sessions/week of 4 × 30 s at maximum speed (all-out, a progressive HIIT (proHIIT group performed three exercise sessions/week of 4 × 30 s at maximum speed (all-out with one extra session every week (up to 7 × 30 s and a low-intensity training (LIT control group performed three exercise sessions/week for 25 min <75% of maximum heart rate. Exercise miR-126-3p/-5p plasma levels were determined using capillary blood from earlobes.Results: No exercise-induced increase in miR-126 levels was detected at baseline, neither in the LIT (after 25 min low-intensity running nor the HIIT groups (after 4 min of high-intensity running. After the intervention, the LIT group presented an increase in miR-126-3p, while in the HIIT group, miR-126-3p levels were still reduced (all p < 0.05. An increase for both, miR-126-3p and -5p levels (all p < 0.05, pre- vs. during and post-exercise was detected in the proHIIT group. Between group analysis revealed that miR-126-3p levels after LIT and proHIIT increased by 2.12 ± 2.55 and 1.24 ± 2.46 units (all p < 0.01, respectively, compared to HIIT (−1.05 ± 2.6 units.Conclusions: LIT and proHIIT may be performed to increase individual miR-126 levels. HIIT without progression was less effective in increasing miR-126.

  3. Dose-Response of Sodium Bicarbonate Ingestion Highlights Individuality in Time Course of Blood Analyte Responses.

    Science.gov (United States)

    Jones, Rebecca Louise; Stellingwerff, Trent; Artioli, Guilherme Giannini; Saunders, Bryan; Cooper, Simon; Sale, Craig

    2016-10-01

    To defend against hydrogen cation accumulation and muscle fatigue during exercise, sodium bicarbonate (NaHCO 3 ) ingestion is commonplace. The individualized dose-response relationship between NaHCO 3 ingestion and blood biochemistry is unclear. The present study investigated the bicarbonate, pH, base excess and sodium responses to NaHCO 3 ingestion. Sixteen healthy males (23 ± 2 years; 78.6 ± 15.1 kg) attended three randomized order-balanced, nonblinded sessions, ingesting a single dose of either 0.1, 0.2 or 0.3 g·kg -1 BM of NaHCO 3 (Intralabs, UK). Fingertip capillary blood was obtained at baseline and every 10 min for 1 hr, then every 15 min for a further 2 hr. There was a significant main effect of both time and condition for all assessed blood analytes (p ≤ .001). Blood analyte responses were significantly lower following 0.1 g·kg -1 BM compared with 0.2 g·kg -1 BM; bicarbonate concentrations and base excess were highest following ingestion of 0.3 g·kg -1 BM (p ≤ .01). Bicarbonate concentrations and pH significantly increased from baseline following all doses; the higher the dose the greater the increase. Large interindividual variability was shown in the magnitude of the increase in bicarbonate concentrations following each dose (+2.0-5; +5.1-8.1; and +6.0-12.3 mmol·L -1 for 0.1, 0.2 and 0.3 g·kg -1 BM) and in the range of time to peak concentrations (30-150; 40-165; and 75-180 min for 0.1, 0.2 and 0.3 g·kg -1 BM). The variability in bicarbonate responses was not affected by normalization to body mass. These results challenge current practices relating to NaHCO 3 supplementation and clearly show the need for athletes to individualize their ingestion protocol and trial varying dosages before competition.

  4. Patient-provider relationship predicts mental and physical health indicators for HIV-positive men who have sex with men.

    Science.gov (United States)

    Bankoff, Sarah M; McCullough, Mary B; Pantalone, David W

    2013-06-01

    We used secondary data analysis to examine associations among aspects of patient-provider relationships and mental and physical health indicators. Positive patient perceptions of patient-provider relationships were associated with fewer mental health symptoms in this outpatient sample of HIV-positive men who have sex with men (N = 171). Regression analyses revealed the role of anxiety and depression in explaining associations between two aspects of patient-provider relationships (i.e. quality of information offered and provider interactional style) and health-related quality of life. The findings demonstrated the importance of patient-provider relationships to improving physical health and functioning and maintaining engagement in care, among HIV-positive men who have sex with men.

  5. Fathers make a difference: positive relationships with mother and baby in relation to infant colic.

    Science.gov (United States)

    Alexander, C P; Zhu, J; Paul, I M; Kjerulff, K H

    2017-09-01

    Maternal psychological factors like depression, anxiety and stress have been associated with infant fussiness or colic. However, little research exists on whether positive factors such as social support and the happiness of the mother-partner relationship are associated with lower rates of infant fussiness or colic. We investigated the association between infant colic and three types of maternal support: general maternal social support (during pregnancy and post partum), the happiness of the mother-partner relationship (during pregnancy and post partum) and partner involvement in caring for the newborn. Participants were 3006 women in the First Baby Study, a prospective study of the effect of mode of first delivery on subsequent childbearing. Women were interviewed by telephone during pregnancy and 1 month after first childbirth and asked about social support and if their baby had a variety of problems since birth, including 'Colic - crying or fussiness three or more hours a day'. Multivariable logistic regression models were used to model the association between maternal support and infant colic, controlling for confounders, including maternal race or ethnicity, insurance, marital status, smoking, mode of delivery, maternal post-partum depression, breastfeeding, other neonatal illnesses and newborn gestational age. Infant colic was reported by 11.6% of new mothers. High general maternal social support (in comparison with low), measured during pregnancy, was associated with lower reported infant colic (adjusted odds ratio (AOR), 0.55, 95% confidence interval (CI), 0.40-0.75) and measured post partum (AOR, 0.51, 95% CI, 0.39-0.67); high relationship happiness (in comparison with low), measured during pregnancy (AOR, 0.71, 95% CI, 0.54-0.93), and measured post partum (AOR, 0.22, 95% CI, 0.12-0.40); and high partner involvement with newborn care (in comparison with low) (AOR, 0.60, 95% CI, 0.44-0.81). Higher levels of maternal social support during pregnancy and post

  6. Association between dietary vitamin C intake and risk of esophageal cancer: A dose-response meta-analysis.

    Science.gov (United States)

    Bo, Yacong; Lu, Yan; Zhao, Yan; Zhao, Erjiang; Yuan, Ling; Lu, Weiquan; Cui, Lingling; Lu, Quanjun

    2016-04-15

    While several epidemiological studies have investigated the association between vitamin C and risk of esophageal cancer, the results remain inconsistent. In the present study, a meta-analysis was conducted to assess the impact of dietary vitamin C intake on esophageal cancer risk. Online databases were searched up to March 29, 2015, for studies on the association between dietary vitamin C intake and esophageal cancer risk. Pooled risk ratios (RRs) or odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using a random-effects model. Dose-response analyses were performed using the method of restricted cubic splines with four knots at percentiles of 5, 35, 65 and 95% of the distribution. Publication bias was estimated using Egger's tests and funnel plots. In all, 15 articles were included in this meta-analysis, including 20 studies, containing 7063 controls and 3955 cases of esophageal cancer. By comparing the highest vs. the lowest categories of vitamin C intake, we found that vitamin C was inversely associated with the risk of esophageal cancer [overall OR = 0.58, 95% CI = 0.49-0.68, I(2) = 56%]. A linear dose-response relationship was found. With an increase in dietary vitamin C intake of 50 mg/day, the risk of esophageal cancer statistically decreased by 13% (OR = 0.87, 95% CI = 0.80-0.93, p(linearity) = 0.0002). In conclusion, our analysis suggested that the higher intake of dietary vitamin C might have a protective effect against esophageal cancer. © 2015 UICC.

  7. Dose-Response Head-to-Head Comparison of Inodilators Dobutamine, Milrinone, and Levosimendan in Chronic Experimental Pulmonary Hypertension.

    Science.gov (United States)

    Tavares-Silva, Marta; Alaa, Mohamed; Leite, Sara; Oliveira-Pinto, José; Lopes, Lucas; Leite-Moreira, Adelino F; Lourenço, André P

    2017-09-01

    The choice of inodilator drug in the acute management of patients with pulmonary hypertension (PH) having right ventricular (RV) failure remains unsettled and challenging. Comprehensive experimental evaluations may provide further insight and fundamental translational research clues to support inodilator selection and clinical trial design. Our aim was to compare acute dose-response hemodynamic effects of inodilators dobutamine (DOB), milrinone (MIL), and levosimendan (LEV) in chronic experimental PH. Seven-week-old male Wistar rats were randomly injected with 60 mg·kg -1 monocrotaline (MCT) or vehicle (Ctrl, n = 7) and underwent systemic and pulmonary artery (PA) pressure and RV pressure-volume (PV) hemodynamic evaluation under halogenate anesthesia 24 to 30 days after injection. The MCT-injected animals (n = 7 each) randomly received dose-response infusions of DOB (1, 3, 6 and 12 μg·kg -1 ·min -1 ), MIL (MIL: 1, 3, 6 and 12 μg·kg -1 ·min -1 ), or LEV (0.3, 0.6, 1.2 and 2.4 μg·kg -1 ·min -1 ). Load-independent indexes were obtained by inferior vena cava occlusion at baseline and after the last dose. All inodilators increased RV ejection fraction, preload recruitable stroke work, and ventricular-vascular coupling without jeopardizing perfusion pressure. Dobutamine raised heart rate and PA pressure. Only LEV increased cardiac index and decreased PA elastance and pulmonary vascular resistance (PVR). Moreover, only LEV downward-shifted the end-diastolic PV relationship, thereby improving RV compliance. Adding sildenafil to LEV further decreased PVR. Levosimendan had beneficial acute systolic and diastolic functional effects in experimental chronic PH and RV afterload compared to DOB and MIL. It should be further tested in clinical trials enrolling patients with PH in the perioperative and critical care settings.

  8. Soy food intake and risk of gastric cancer: A dose-response meta-analysis of prospective studies.

    Science.gov (United States)

    Weng, Ke-Gui; Yuan, Ya-Ling

    2017-08-01

    Epidemiological studies were inconsistent on the association between soy food intake and risk of gastric cancer (GC). This study aimed to determine the role of soy food intake in the development of GC.A systematic search was conducted in PubMed and Web of Science to identify all relevant studies. Study-specific relative risks (RRs) and 95% confidence intervals (CIs) were pooled using a random-effects model, and the dose-response relationship between soy food intake and GC risk was also assessed.Thirteen prospective studies were identified with a total of 517,106 participants and 5800 cases. Among 11 types of soy food, high intake of total soy food (the highest vs the lowest category: RR: 0.78, 95% CI: 0.62-0.98) and nonfermented soy food (RR: 0.63, 95% CI: 0.50-0.79) were inversely associated with GC risk, while high intake of miso soup was associated with the risk in male (RR: 1.17, 95% CI: 1.02-1.36). In dose-response meta-analysis, total soy food intake (0-150 g/day) showed no significant association with GC risk, while high intake of nonfermented soy food was inversely related, especially an intake of more than 100 g/day. In male, miso soup intake (1-5 cups/day) was significantly associated with GC risk.High intake of nonfermented soy food might reduce the risk of GC, while miso soup intake might increase the risk in male.

  9. Interaction of bistable glass-coated microwires in different positional relationship

    Energy Technology Data Exchange (ETDEWEB)

    Rodionova, V., E-mail: rodionova@magn.ru [Magnetism Department, Faculty of Physics, M.V. Lomonosov Moscow State University, 119991 Moscow (Russian Federation); Immanuel Kant Baltic Federal University, 236041 Kaliningrad (Russian Federation); Kudinov, N. [Magnetism Department, Faculty of Physics, M.V. Lomonosov Moscow State University, 119991 Moscow (Russian Federation); Zhukov, A. [Departamento Fisica de Materiales, Facultad Quimicas, UPV/EHU, 20018 San Sebastian (Spain); IKERBASQUE, Basque Foundation for Science, 48011 Bilbao (Spain); Perov, N. [Magnetism Department, Faculty of Physics, M.V. Lomonosov Moscow State University, 119991 Moscow (Russian Federation)

    2012-05-01

    The amorphous ferromagnetic glass-coated microwires with positive magnetostriction constant of the metallic core possess the bistable magnetization reversal and the fast domain wall propagation along the microwire axis. These properties and also the magnetization processes in the systems of the microwires are of interest in the magnetic sensing technology, encoding systems and smart composite applications. In this work we present the results of the experimental investigation, simulations and theoretical estimations of the hysteresis process in the systems of the magnetically bistable microwires with different length and positional relationship between them. The location of the short microwires near the long microwire affects the switching fields (external coaxial magnetic field applied for starting of the domain wall propagation along the microwire axis) and the hysteresis process. The changes of these properties are not directly proportional to the value of the shorter microwire shift along the longer one. When the short microwire was placed in the middle of the long one and when the one end of the long microwire coincided with the end of the short one, the two-steps hysteresis loops were observed for both sample orientations: before and after sample rotation on 180 Degree-Sign . When the short microwire was placed close to the end of the long microwire (but did not coincide with it) we observed at first the two-steps hysteresis loop and single step behavior for one branch of the hysteresis loop after sample rotation. Moreover, changing of the orientation of the samples results in the shift of the switching field of the shorter microwire when its end was located near the end or coincided with the end of the longer one. This uncommon hysteresis behavior was explained and illustrated using results of the simulations. The values of microwires interaction were also estimated.

  10. Interaction of bistable glass-coated microwires in different positional relationship

    International Nuclear Information System (INIS)

    Rodionova, V.; Kudinov, N.; Zhukov, A.; Perov, N.

    2012-01-01

    The amorphous ferromagnetic glass-coated microwires with positive magnetostriction constant of the metallic core possess the bistable magnetization reversal and the fast domain wall propagation along the microwire axis. These properties and also the magnetization processes in the systems of the microwires are of interest in the magnetic sensing technology, encoding systems and smart composite applications. In this work we present the results of the experimental investigation, simulations and theoretical estimations of the hysteresis process in the systems of the magnetically bistable microwires with different length and positional relationship between them. The location of the short microwires near the long microwire affects the switching fields (external coaxial magnetic field applied for starting of the domain wall propagation along the microwire axis) and the hysteresis process. The changes of these properties are not directly proportional to the value of the shorter microwire shift along the longer one. When the short microwire was placed in the middle of the long one and when the one end of the long microwire coincided with the end of the short one, the two-steps hysteresis loops were observed for both sample orientations: before and after sample rotation on 180°. When the short microwire was placed close to the end of the long microwire (but did not coincide with it) we observed at first the two-steps hysteresis loop and single step behavior for one branch of the hysteresis loop after sample rotation. Moreover, changing of the orientation of the samples results in the shift of the switching field of the shorter microwire when its end was located near the end or coincided with the end of the longer one. This uncommon hysteresis behavior was explained and illustrated using results of the simulations. The values of microwires interaction were also estimated.

  11. Examining the relationship between local extinction risk and position in range.

    Science.gov (United States)

    Boakes, Elizabeth H; Isaac, Nicholas J B; Fuller, Richard A; Mace, Georgina M; McGowan, Philip J K

    2018-02-01

    Over half of globally threatened animal species have experienced rapid geographic range loss. Identifying the parts of species' distributions most vulnerable to local extinction would benefit conservation planning. However, previous studies give little consensus on whether ranges decline to the core or edge. We built on previous work by using empirical data to examine the position of recent local extinctions within species' geographic ranges, address range position as a continuum, and explore the influence of environmental factors. We aggregated point-locality data for 125 Galliform species from across the Palearctic and Indo-Malaya into equal-area half-degree grid cells and used a multispecies dynamic Bayesian occupancy model to estimate rates of local extinctions. Our model provides a novel approach to identify loss of populations from within species ranges. We investigated the relationship between extinction rates and distance from range edge by examining whether patterns were consistent across biogeographic realm and different categories of land use. In the Palearctic, local extinctions occurred closer to the range edge than range core in both unconverted and human-dominated landscapes. In Indo-Malaya, no pattern was found for unconverted landscapes, but in human-dominated landscapes extinctions tended to occur closer to the core than the edge. Our results suggest that local and regional factors override general spatial patterns of recent local extinction within species' ranges and highlight the difficulty of predicting the parts of a species' distribution most vulnerable to threat. © 2017 The Authors. Conservation Biology published by Wiley Periodicals, Inc. on behalf of Society for Conservation Biology.

  12. Food Groups and Risk of Hypertension: A Systematic Review and Dose-Response Meta-Analysis of Prospective Studies.

    Science.gov (United States)

    Schwingshackl, Lukas; Schwedhelm, Carolina; Hoffmann, Georg; Knüppel, Sven; Iqbal, Khalid; Andriolo, Violetta; Bechthold, Angela; Schlesinger, Sabrina; Boeing, Heiner

    2017-11-01

    The aim of this systematic review and meta-analysis was to summarize the evidence on the relation of the intakes of 12 major food groups, including whole grains, refined grains, vegetables, fruits, nuts, legumes, eggs, dairy, fish, red meat, processed meat, and sugar-sweetened beverages (SSBs) with the risk of hypertension. PubMed, Scopus, and Web of Science were searched systematically until June 2017 for prospective studies having quantitatively investigated the above-mentioned foods. We conducted meta-analysis on the highest compared with the lowest intake categories and linear and nonlinear dose-response meta-analyses to analyze the association. Summary RRs and 95% CIs were estimated by using a random-effects model. Overall, 28 reports were included in the meta-analysis. An inverse association for the risk of hypertension was observed for 30 g whole grains/d (RR: 0.92; 95% CI: 0.87, 0.98), 100 g fruits/d (RR: 0.97; 95% CI: 0.96, 0.99), 28 g nuts/d (RR: 0.70; 95% CI: 0.45, 1.08), and 200 g dairy/d (RR: 0.95; 95% CI: 0.94, 0.97), whereas a positive association for 100 g red meat/d (RR: 1.14; 95% CI: 1.02, 1.28), 50 g processed meat/d (RR: 1.12; 95% CI: 1.00, 1.26), and 250 mL SSB/d (RR: 1.07; 95% CI: 1.04, 1.10) was seen in the linear dose-response meta-analysis. Indication for nonlinear relations of the intakes of whole grains, fruits, fish, and processed meats with the risk of hypertension was detected. In summary, this comprehensive dose-response meta-analysis of 28 reports identified optimal intakes of whole grains, fruits, nuts, legumes, dairy, red and processed meats, and SSBs related to the risk of hypertension. These findings need to be seen under the light of very-low to low quality of meta-evidence. However, the findings support the current dietary guidelines in the prevention of hypertension. © 2017 American Society for Nutrition.

  13. Lipid metabolic dose response to dietary alpha-linolenic acid in monk parrot (Myiopsitta monachus).

    Science.gov (United States)

    Petzinger, Christina; Heatley, J J; Bailey, Christopher A; Bauer, John E

    2014-03-01

    Monk parrots (Myiopsitta monachus) are susceptible to atherosclerosis, a progressive disease characterized by the formation of plaques in the arteries accompanied by underlying chronic inflammation. The family of n-3 fatty acids, especially eicosapentaenoic acid (20:5n-3, EPA) and docosahexaenoic acid (22:6n-3, DHA), have consistently been shown to reduce atherosclerotic risk factors in humans and other mammals. Some avian species have been observed to convert α-linolenic acid (18:3n-3, ALA) to EPA and DHA (Htin et al. in Arch Geflugelk 71:258-266, 2007; Petzinger et al. in J Anim Physiol Anim Nutr, 2013). Therefore, the metabolic effects of including flaxseed oil, as a source of ALA, in the diet at three different levels (low, medium, and high) on the lipid metabolism of Monk parrots was evaluated through measuring plasma total cholesterol (TC), free cholesterol (FC), triacylglycerols (TAG), and phospholipid fatty acids. Feed intake, body weight, and body condition score were also assessed. Thus the dose and possible saturation response of increasing dietary ALA at constant linoleic acid (18:2n-6, LNA) concentration on lipid metabolism in Monk parrots (M. monachus) was evaluated. Calculated esterified cholesterol in addition to plasma TC, FC, and TAG were unaltered by increasing dietary ALA. The high ALA group had elevated levels of plasma phospholipid ALA, EPA, and docosapentaenoic acid (DPAn-3, 22:5n-3). The medium and high ALA groups had suppressed plasma phospholipid 20:2n-6 and adrenic acid (22:4n-6, ADA) compared to the low ALA group. When the present data were combined with data from a previous study (Petzinger et al. in J Anim Physiol Anim Nutr, 2013) a dose response to dietary ALA was observed when LNA was constant. Plasma phospholipid ALA, EPA, DPAn-3, DHA, and total n-3 were positively correlated while 20:2n-6, di-homo-gamma-linoleic acid (20:3n-6Δ7), arachidonic acid (20:4n-6), ADA, and total n-6 were inversely correlated with dietary en% ALA.

  14. Authoritarian parenting attitudes and social origin: The multigenerational relationship of socioeconomic position to childrearing values.

    Science.gov (United States)

    Friedson, Michael

    2016-01-01

    Support for authoritarian approaches to parenting, including corporal punishment, is known to be elevated among individuals with low current levels of socioeconomic attainment. The objectives of this study are: (1) to determine whether authoritarian parenting dispositions are related to disadvantages in one's social background, in addition to one's present socioeconomic standing; and (2) to distinguish, in this regard, between support for spanking and other authoritarian parenting dispositions. Ordered logit models, applied to General Social Survey data concerning a nationally representative sample of US adults, are used to examine relationships of authoritarian parenting dispositions to the socioeconomic positions that respondents currently occupy and in which they were raised. It is found that support for spanking (N=10,725) and valuing of obedience (N=10,043) are inversely related to the socioeconomic status (SES) of one's family of origin, and that these associations are robust to controls for one's current SES. A disadvantaged family background is found to increase support for spanking most among those with high current SES. Strong associations (robust to controls for SES indicators) are additionally found between African-American racial identity and support for authoritarian parenting. Prior research indicates that authoritarian parenting practices such as spanking may be harmful to children. Thus, if the parenting attitudes analyzed here translate into parenting practices, then this study's findings may point to a mechanism for the intergenerational transmission of disadvantages. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. The relationship between radiation load and chromosome aberrations in permanent staff of nuclear facilities

    International Nuclear Information System (INIS)

    Heubisch, W.

    1982-01-01

    Employees of nuclear power stations can be exposed to an increased risk. Using chromosome analytical methods an attempt is made to establish a dose-response relationship for relatively low radiation dose levels. Chromosome aberrations in lymphocytes at the stage of mitosis were classified according to morphological structure and gaps. Correlation and regression analysis produced a positive relationship compared to the previous year's dose and aberrations, whereas no dependence could be proved for the actual age dose and age. (DG) [de

  16. Aspirin as a potential modality for the chemoprevention of breast cancer: A dose-response meta-analysis of cohort studies from 857,831 participants.

    Science.gov (United States)

    Lu, Liming; Shi, Leiyu; Zeng, Jingchun; Wen, Zehuai

    2017-06-20

    Previous meta-analyses on the relationship between aspirin use and breast cancer risk have drawn inconsistent results. In addition, the threshold effect of different doses, frequencies and durations of aspirin use in preventing breast cancer have yet to be established. The search yielded 13 prospective cohort studies (N=857,831 participants) that reported an average of 7.6 cases/1,000 person-years of breast cancer during a follow-up period of from 4.4 to 14 years. With a random effects model, a borderline significant inverse association was observed between overall aspirin use and breast cancer risk, with a summarized RR = 0.94 (P = 0.051, 95% CI 0.87-1.01). The linear regression model was a better fit for the dose-response relationship, which displayed a potential relationship between the frequency of aspirin use and breast cancer risk (RR = 0.97, 0.95 and 0.90 for 5, 10 and 20 times/week aspirin use, respectively). It was also a better fit for the duration of aspirin use and breast cancer risk (RR = 0.86, 0.73 and 0.54 for 5, 10 and 20 years of aspirin use). We searched MEDLINE, EMBASE and CENTRAL databases through early October 2016 for relevant prospective cohort studies of aspirin use and breast cancer risk. Meta-analysis of relative risks (RR) estimates associated with aspirin intake were presented by fixed or random effects models. The dose-response meta-analysis was performed by linear trend regression and restricted cubic spline regression. Our study confirmed a dose-response relationship between aspirin use and breast cancer risk. For clinical prevention, long term (>5 years) consistent use (2-7 times/week) of aspirin appears to be more effective in achieving a protective effect against breast cancer.

  17. Childhood adversity specificity and dose-response effect in non-affective first-episode psychosis

    DEFF Research Database (Denmark)

    Trauelsen, Anne Marie; Bendall, Sarah; Jansen, Jens Einar

    2015-01-01

    BACKGROUND: Reviews conclude that childhood and adolescence sexual, physical, emotional abuse and emotional and physical neglect are all risk factors for psychosis. However, studies suggest only some adversities are associated with psychosis. Dose-response effects of several adversities on risk......% of the control group. Childhood and adolescent sexual, physical, emotional abuse, and physical and emotional neglect, separation and institutionalization were about four to 17 times higher for the FEP group (all p... of psychosis have not been consistently found. The current study aimed to explore adversity specificity and dose-response effects of adversities on risk of psychosis. METHOD: Participants were 101 persons with first-episode psychosis (FEP) diagnosed with ICD-10 F20 - F29 (except F21) and 101 non-clinical...

  18. Aspartame tablets-gamma dose response and usability for routine radiation processing dosimetry using spectrophotometry

    Energy Technology Data Exchange (ETDEWEB)

    Shinde, S.H. [Radiation Safety Systems Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India)]. E-mail: shs_barc@yahoo.com; Mukherjee, T. [Radiation Safety Systems Division, Chemistry Group, Bhabha Atomic Research Centre, Mumbai 400 085 (India)

    2007-02-15

    Aspartame tablets were studied for gamma dose response, using spectrophotometric read-out method. The optimum concentration for ferrous ions was 2x10{sup -4}moldm{sup -3} and xylenol orange with 2.5x10{sup -1}moldm{sup -3} of sulphuric acid for the optimum acidity in FX solution. Wavelength of maximum absorbance is 548nm. Post-irradiation stability is appreciable i.e. for not less than one month. Dose response is non-linear with third order polynomial fit, in the dose range of 1000-10000Gy. This system of aspartame was further used for carrying out relative percentage dose profile measurement in Gamma Cell-220. Results obtained were inter-compared with that of a glutamine dosimeter, which showed that maximum difference between the values of aspartame and glutamine systems is within +/-10%.

  19. Dose response of artificial irradiation of fluvial sediment sample for ESR dating

    International Nuclear Information System (INIS)

    Liu Chunru; Yin Gongming; Gao Lu; Li Jianping; Han Fei; Lin Min

    2011-01-01

    ESR dating samples need be irradiated to obtain dose response curve and the equivalent dose. The artificial dose rate is about 1 x 10 -1 -1 x 10 2 Gy/min, whereas the natural dose rate is about 3 Gy/ka. Therefore, one must be sure whether the much higher artificial dose rate is suitable for the ESR dating study. In this paper, we use different artificial dose rate to irradiate the same fluvial sample and measure the quartz Al centre ESR signal under the same conditions. The dose response curves are compared, in an attempt to gain a preliminary knowledge on that problem and build a good foundation for our ESR dating studies on fluvial samples. (authors)

  20. Bayesian nonparametric estimation of continuous monotone functions with applications to dose-response analysis.

    Science.gov (United States)

    Bornkamp, Björn; Ickstadt, Katja

    2009-03-01

    In this article, we consider monotone nonparametric regression in a Bayesian framework. The monotone function is modeled as a mixture of shifted and scaled parametric probability distribution functions, and a general random probability measure is assumed as the prior for the mixing distribution. We investigate the choice of the underlying parametric distribution function and find that the two-sided power distribution function is well suited both from a computational and mathematical point of view. The model is motivated by traditional nonlinear models for dose-response analysis, and provides possibilities to elicitate informative prior distributions on different aspects of the curve. The method is compared with other recent approaches to monotone nonparametric regression in a simulation study and is illustrated on a data set from dose-response analysis.

  1. Aspartame tablets-gamma dose response and usability for routine radiation processing dosimetry using spectrophotometry

    International Nuclear Information System (INIS)

    Shinde, S.H.; Mukherjee, T.

    2007-01-01

    Aspartame tablets were studied for gamma dose response, using spectrophotometric read-out method. The optimum concentration for ferrous ions was 2x10 -4 moldm -3 and xylenol orange with 2.5x10 -1 moldm -3 of sulphuric acid for the optimum acidity in FX solution. Wavelength of maximum absorbance is 548nm. Post-irradiation stability is appreciable i.e. for not less than one month. Dose response is non-linear with third order polynomial fit, in the dose range of 1000-10000Gy. This system of aspartame was further used for carrying out relative percentage dose profile measurement in Gamma Cell-220. Results obtained were inter-compared with that of a glutamine dosimeter, which showed that maximum difference between the values of aspartame and glutamine systems is within +/-10%

  2. Single-dose-response curves of murine gastrointestinal crypt stem cells

    International Nuclear Information System (INIS)

    Masuda, K.; Withers, H.R.; Mason, K.A.; Chen, K.Y.

    1977-01-01

    Dose-response curves for the reproductive capacity of crypt stem cells of murine colonic, jejunal, and gastric mucosae exposed in situ to multifractionated gamma ray exposures were analyzed and single-dose-survival curves of these cells were constructed. The following conclusions were drawn: (1) The single-dose-response curves bend downward over a dose range of approximately 200 to 1500 rad; (2) cell death seems to be due to nonrepairable damage at doses less than 250 rad for colon, and 220 rad for jejunum; (3) there are 21, 110, and 140 stem cells per crypt of gastric, colonic, and jejunal mucosa, respectively; and (4) jejunal stem cells are the most radiosensitive and gastric mucosal stem cells are the most resistant

  3. Identified Phases in the Building and Maintaining of Positive Teacher-Student Relationships

    Science.gov (United States)

    Newberry, Melissa

    2010-01-01

    Teacher-student relationships are accepted as influential but the dynamics of those relationships are not well understood, especially with difficult students. A series of interviews were combined with classroom observations and written reflections to understand in what ways a teacher negotiated her relationship with a behaviorally challenging…

  4. Positive valence bias and parent-child relationship security moderate the association between early institutional caregiving and internalizing symptoms

    Science.gov (United States)

    VanTieghem, Michelle R.; Gabard-Durnam, Laurel; Goff, Bonnie; Flannery, Jessica; Humphreys, Kathryn L.; Telzer, Eva H.; Caldera, Christina; Louie, Jennifer Y.; Shapiro, Mor; Bolger, Niall; Tottenham, Nim

    2018-01-01

    Institutional caregiving is associated with significant deviations from species-expected caregiving, altering the normative sequence of attachment formation and placing children at risk for long-term emotional difficulties. However, little is known about factors that can promote resilience following early institutional caregiving. In the current study, we investigated how adaptations in affective processing (i.e. positive valence bias) and family-level protective factors (i.e. secure parent-child relationships) moderate risk for internalizing symptoms in Previously Institutionalized (PI) youth. Children and adolescents with and without a history of institutional care performed a laboratory-based affective processing task and self-reported measures of parent-child relationship security. PI youth were more likely than comparison youth to show positive valence biases when interpreting ambiguous facial expressions. Both positive valence bias and parent-child relationship security moderated the association between institutional care and parent-reported internalizing symptoms, such that greater positive valence bias and more secure parent-child relationships predicted fewer symptoms in PI youth. However, when both factors were tested concurrently, parent-child relationship security more strongly moderated the link between PI status and internalizing symptoms. These findings suggest that both individual-level adaptations in affective processing and family-level factors of secure parent-child relationships may ameliorate risk for internalizing psychopathology following early institutional caregiving. PMID:28401841

  5. Perceived positive teacher-student relationship as a protective factor for Chinese left-behind children's emotional and behavioural adjustment.

    Science.gov (United States)

    Liu, Yan; Li, Xiaowei; Chen, Li; Qu, Zhiyong

    2015-10-01

    Using cross-sectional data collected in rural communities of two provinces of China, this study examined the protective role of perceived positive teacher-student relationship for Chinese left-behind children. The participants included 1442 children with a mean age of 14.13 classified into two groups: a left-behind group (104 boys and 110 girls) and a comparison group (588 boys and 640 girls). Self-reported questionnaires concerning self-esteem, depression, problem behaviours and the teacher-student relationship were administered. Relative to the comparison group, after controlling for age, gender and family socioeconomic status, the left-behind group was disadvantaged in terms of self-esteem and depression but not in problem behaviours. As hypothesised, the results of regression analyses indicated that teacher-student relationship positively predicted self-esteem and negatively predicted depression and problem behaviours for both groups. Moreover, the association between teacher-student relationship and depression was stronger among the left-behind group, suggesting that left-behind children were more responsive to the positive effect of a desired teacher-student relationship. Taken together, the results of our study support the idea that perceived positive teacher-student relationship may serve as a protective factor for left-behind children. Practical implications and limitations of the present study are discussed. © 2014 International Union of Psychological Science.

  6. Positive valence bias and parent-child relationship security moderate the association between early institutional caregiving and internalizing symptoms.

    Science.gov (United States)

    Vantieghem, Michelle R; Gabard-Durnam, Laurel; Goff, Bonnie; Flannery, Jessica; Humphreys, Kathryn L; Telzer, Eva H; Caldera, Christina; Louie, Jennifer Y; Shapiro, Mor; Bolger, Niall; Tottenham, Nim

    2017-05-01

    Institutional caregiving is associated with significant deviations from species-expected caregiving, altering the normative sequence of attachment formation and placing children at risk for long-term emotional difficulties. However, little is known about factors that can promote resilience following early institutional caregiving. In the current study, we investigated how adaptations in affective processing (i.e., positive valence bias) and family-level protective factors (i.e., secure parent-child relationships) moderate risk for internalizing symptoms in previously institutionalized (PI) youth. Children and adolescents with and without a history of institutional care performed a laboratory-based affective processing task and self-reported measures of parent-child relationship security. PI youth were more likely than comparison youth to show positive valence biases when interpreting ambiguous facial expressions. Both positive valence bias and parent-child relationship security moderated the association between institutional care and parent-reported internalizing symptoms, such that greater positive valence bias and more secure parent-child relationships predicted fewer symptoms in PI youth. However, when both factors were tested concurrently, parent-child relationship security more strongly moderated the link between PI status and internalizing symptoms. These findings suggest that both individual-level adaptations in affective processing and family-level factors of secure parent-child relationships may ameliorate risk for internalizing psychopathology following early institutional caregiving.

  7. A new method for synthesizing radiation dose-response data from multiple trials applied to prostate cancer

    DEFF Research Database (Denmark)

    Diez, Patricia; Vogelius, Ivan S; Bentzen, Søren M

    2010-01-01

    A new method is presented for synthesizing dose-response data for biochemical control of prostate cancer according to study design (randomized vs. nonrandomized) and risk group (low vs. intermediate-high).......A new method is presented for synthesizing dose-response data for biochemical control of prostate cancer according to study design (randomized vs. nonrandomized) and risk group (low vs. intermediate-high)....

  8. A comparison of dose-response models for death from hematological depression

    International Nuclear Information System (INIS)

    Morris, M.D.; Jones, T.D.

    1987-01-01

    Many radiation-induced lethality experiments that have been published for various mammalian species have been compiled into a database suitable to study interspecific variability of radiosensitivity, dose-rate dependence of sensitivity, dose-response behavior within each experiment, etc. The data compiled were restricted to continuous and nearly continuous exposures to photon radiations having source energies above 100 keV. Also, photon source energy, exposure geometry, and body weight considerations were used to select studies where the dose to hematopoietic marrow was nearly uniform, i.e., < +- 20%. The data base reflects 13 mammalian test species ranging from mouse to cattle. Some 211 studies were compiled but only 105 were documented in adequate detail to be useful in development and evaluation of dose-response models of interest to practical human exposures. Of the 105 studies, 70 were for various rodent species, and 35 were for nonrodent groups ranging from standard laboratory primates (body weight ∼5 kg) to cattle (body weight 375 kg). This paper considers seven different dose-response models which are tested for validity against those 105 studies. The dose-response models included: a right-skewed extreme value, a left-skewed extreme value model, log-logistic, log-probit, logistic, probit, and Weibull models. In general, the log transformed models did not improve model performance and the extreme value models did not seem consistent with the preponderance of the data. Overall, the probit and the logistic models seemed preferable over the Weibull model. 30 refs., 8 tabs

  9. Dose response of hydrazine - Deproteinated tooth enamel under blue light stimulation

    Energy Technology Data Exchange (ETDEWEB)

    Yuece, Ulkue Rabia, E-mail: ulkuyuce@hotmail.co [Ankara University, Faculty of Engineering, Department of Engineering Physics, 06100, Tandogan - Ankara (Turkey); Meric, Niyazi, E-mail: meric@ankara.edu.t [Ankara University, Faculty of Engineering, Department of Engineering Physics, 06100, Tandogan - Ankara (Turkey); Atakol, Orhan, E-mail: atakol@science.ankara.edu.t [Ankara University, Science Faculty, Department of Chemistry, 06100, Tandogan - Ankara (Turkey); Yasar, Fusun, E-mail: ab121310@adalet.gov.t [Council of Forensic Medicine, Ankara Branch, Ankara (Turkey)

    2010-08-15

    The beta dose response and Optically Stimulated Luminescence (OSL) signal stability characteristics of human tooth enamel deproteinated by hydrazine reagent under blue photon stimulation are reported. Removal of the protein organic component of tooth enamel resulted in a higher OSL sensitivity and slower fading of OSL signals. The effect of chemical sample preparation on the enamel sample sensitivity is discussed and further steps to make this deproteinization treatment suitable for in vitro dose reconstruction studies are suggested.

  10. Dose response of hydrazine - Deproteinated tooth enamel under blue light stimulation

    International Nuclear Information System (INIS)

    Yuece, Ulkue Rabia; Meric, Niyazi; Atakol, Orhan; Yasar, Fusun

    2010-01-01

    The beta dose response and Optically Stimulated Luminescence (OSL) signal stability characteristics of human tooth enamel deproteinated by hydrazine reagent under blue photon stimulation are reported. Removal of the protein organic component of tooth enamel resulted in a higher OSL sensitivity and slower fading of OSL signals. The effect of chemical sample preparation on the enamel sample sensitivity is discussed and further steps to make this deproteinization treatment suitable for in vitro dose reconstruction studies are suggested.

  11. Analysis of Dose Response for Circulatory Disease After Radiotherapy for Benign Disease

    Energy Technology Data Exchange (ETDEWEB)

    Little, Mark P., E-mail: mark.little@nih.gov [Radiation Epidemiology Branch, National Cancer Institute, Executive Plaza South, Rockville, Maryland (United States); Kleinerman, Ruth A. [Radiation Epidemiology Branch, National Cancer Institute, Executive Plaza South, Rockville, Maryland (United States); Stovall, Marilyn; Smith, Susan A. [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Mabuchi, Kiyohiko [Radiation Epidemiology Branch, National Cancer Institute, Executive Plaza South, Rockville, Maryland (United States)

    2012-12-01

    Purpose: To assess the shape of the dose-response for various circulatory disease endpoints, and modifiers by age and time since exposure. Methods and Materials: This was an analysis of the US peptic ulcer data testing for heterogeneity of radiogenic risk by circulatory disease endpoint (ischemic heart, cerebrovascular, other circulatory disease). Results: There were significant excess risks for all circulatory disease, with an excess relative risk Gy{sup -1} of 0.082 (95% CI 0.031-0.140), and ischemic heart disease, with an excess relative risk Gy{sup -1} of 0.102 (95% CI 0.039-0.174) (both p = 0.01), and indications of excess risk for stroke. There were no statistically significant (p > 0.2) differences between risks by endpoint, and few indications of curvature in the dose-response. There were significant (p < 0.001) modifications of relative risk by time since exposure, the magnitude of which did not vary between endpoints (p > 0.2). Risk modifications were similar if analysis was restricted to patients receiving radiation, although the relative risks were slightly larger and the risk of stroke failed to be significant. The slopes of the dose-response were generally consistent with those observed in the Japanese atomic bomb survivors and in occupationally and medically exposed groups. Conclusions: There were excess risks for a variety of circulatory diseases in this dataset, with significant modification of risk by time since exposure. The consistency of the dose-response slopes with those observed in radiotherapeutically treated groups at much higher dose, as well as in lower dose-exposed cohorts such as the Japanese atomic bomb survivors and nuclear workers, implies that there may be little sparing effect of fractionation of dose or low-dose-rate exposure.

  12. Diethylene glycol-induced toxicities show marked threshold dose response in rats

    Energy Technology Data Exchange (ETDEWEB)

    Landry, Greg M., E-mail: Landry.Greg@mayo.edu [Department of Pharmacology, Toxicology, & Neuroscience, Louisiana State University Health Sciences Center, Shreveport, LA (United States); Dunning, Cody L., E-mail: cdunni@lsuhsc.edu [Department of Pharmacology, Toxicology, & Neuroscience, Louisiana State University Health Sciences Center, Shreveport, LA (United States); Abreo, Fleurette, E-mail: fabreo@lsuhsc.edu [Department of Pathology, Louisiana State University Health Sciences Center, Shreveport, LA (United States); Latimer, Brian, E-mail: blatim@lsuhsc.edu [Department of Pharmacology, Toxicology, & Neuroscience, Louisiana State University Health Sciences Center, Shreveport, LA (United States); Orchard, Elysse, E-mail: eorcha@lsuhsc.edu [Department of Pharmacology, Toxicology, & Neuroscience, Louisiana State University Health Sciences Center, Shreveport, LA (United States); Division of Animal Resources, Louisiana State University Health Sciences Center, Shreveport, LA (United States); McMartin, Kenneth E., E-mail: kmcmar@lsuhsc.edu [Department of Pharmacology, Toxicology, & Neuroscience, Louisiana State University Health Sciences Center, Shreveport, LA (United States)

    2015-02-01

    Diethylene glycol (DEG) exposure poses risks to human health because of widespread industrial use and accidental exposures from contaminated products. To enhance the understanding of the mechanistic role of metabolites in DEG toxicity, this study used a dose response paradigm to determine a rat model that would best mimic DEG exposure in humans. Wistar and Fischer-344 (F-344) rats were treated by oral gavage with 0, 2, 5, or 10 g/kg DEG and blood, kidney and liver tissues were collected at 48 h. Both rat strains treated with 10 g/kg DEG had equivalent degrees of metabolic acidosis, renal toxicity (increased BUN and creatinine and cortical necrosis) and liver toxicity (increased serum enzyme levels, centrilobular necrosis and severe glycogen depletion). There was no liver or kidney toxicity at the lower DEG doses (2 and 5 g/kg) regardless of strain, demonstrating a steep threshold dose response. Kidney diglycolic acid (DGA), the presumed nephrotoxic metabolite of DEG, was markedly elevated in both rat strains administered 10 g/kg DEG, but no DGA was present at 2 or 5 g/kg, asserting its necessary role in DEG-induced toxicity. These results indicate that mechanistically in order to produce toxicity, metabolism to and significant target organ accumulation of DGA are required and that both strains would be useful for DEG risk assessments. - Highlights: • DEG produces a steep threshold dose response for kidney injury in rats. • Wistar and F-344 rats do not differ in response to DEG-induced renal injury. • The dose response for renal injury closely mirrors that for renal DGA accumulation. • Results demonstrate the importance of DGA accumulation in producing kidney injury.

  13. Basic dose response of fluorescent screen-based portal imaging device

    International Nuclear Information System (INIS)

    Yeo, In Hwan; Yonannes, Yonas; Zhu, Yunping

    1999-01-01

    The purpose of this study is to investigate fundamental aspects of the dose response of fluorescent screen-based electronic portal imaging devices (EPIDs). We acquired scanned signal across portal planes as we varied the radiation that entered the EPID by changing the thickness and anatomy of the phantom as well as the air gap between the phantom and the EPID. In addition, we simulated the relative contribution of the scintillation light signal in the EPID system. We have shown that the dose profile across portal planes is a function of the air gap and phantom thickness. We have also found that depending on the density change within the phantom geometry, errors associated with dose response based on the EPID scan can be as high as 7%. We also found that scintillation light scattering within the EPID system is an important source of error. This study revealed and demonstrated fundamental characteristics of dose response of EPID, as relative to that of ion chambers. This study showed that EPID based on fluorescent screen cannot be an accurate dosimetry system

  14. Arsenite Effects on Mitochondrial Bioenergetics in Human and Mouse Primary Hepatocytes Follow a Nonlinear Dose Response

    Directory of Open Access Journals (Sweden)

    Hemantkumar Chavan

    2017-01-01

    Full Text Available Arsenite is a known carcinogen and its exposure has been implicated in a variety of noncarcinogenic health concerns. Increased oxidative stress is thought to be the primary cause of arsenite toxicity and the toxic effect is thought to be linear with detrimental effects reported at all concentrations of arsenite. But the paradigm of linear dose response in arsenite toxicity is shifting. In the present study we demonstrate that arsenite effects on mitochondrial respiration in primary hepatocytes follow a nonlinear dose response. In vitro exposure of primary hepatocytes to an environmentally relevant, moderate level of arsenite results in increased oxidant production that appears to arise from changes in the expression and activity of respiratory Complex I of the mitochondrial proton circuit. In primary hepatocytes the excess oxidant production appears to elicit adaptive responses that promote resistance to oxidative stress and a propensity to increased proliferation. Taken together, these results suggest a nonlinear dose-response characteristic of arsenite with low-dose arsenite promoting adaptive responses in a process known as mitohormesis, with transient increase in ROS levels acting as transducers of arsenite-induced mitohormesis.

  15. Dose-response investigation into glucose facilitation of memory performance and mood in healthy young adults.

    Science.gov (United States)

    Sünram-Lea, Sandra I; Owen, Lauren; Finnegan, Yvonne; Hu, Henglong

    2011-08-01

    It has been suggested that the memory enhancing effect of glucose follows an inverted U-shaped curve, with 25 g resulting in optimal facilitation in healthy young adults. The aim of this study was to further investigate the dose dependency of the glucose facilitation effect in this population across different memory domains and to assess moderation by interindividual differences in glucose regulation and weight. Following a double-blind, repeated measures design, 30 participants were administered drinks containing five different doses of glucose (0 g, 15 g, 25 g, 50 g, and 60 g) and were tested across a range of memory tasks. Glycaemic response and changes in mood state were assessed following drink administration. Analysis of the data showed that glucose administration did not affect mood, but significant glucose facilitation of several memory tasks was observed. However, dose-response curves differed depending on the memory task with only performance on the long-term memory tasks adhering largely to the previously observed inverted U-shaped dose-response curve. Moderation of the response profiles by interindividual differences in glucose regulation and weight was observed. The current data suggest that dose-response function and optimal dose might depend on cognitive domain and are moderated by interindividual differences in glucose regulation and weight.

  16. The shape of the cancer mortality dose-response curve for atomic bomb survivors

    International Nuclear Information System (INIS)

    Pierce, D.A.; Vaeth, M.

    1989-10-01

    The shape of the cancer mortality dose-response in the atomic bomb survivor data is analyzed in the context of linear-quadratic (LQ) models. Results are given for all cancers except leukemia as a group, for leukemia, and for combined inferences assuming common curvature. Since there is substantial information aside from these data suggesting a dose-response concave from above, the emphasis here is not on estimating the best-fitting dose-response curve, but rather on assessing the maximal extent of curvature under LQ models which is consistent with the data. Such inferences are substantially affected by imprecision in the dose estimates, and methods are applied which make explicit allowances for biases due to this. The primary means used here to express the extent of curvature is the factor by which linear risk estimates should be divided to arrive at appropriate low-dose risk estimates. In the past, influential committees have recommended ranges of 2-10 and of 1.5-3 for such a factor. Results here suggest that values greater than about 2 are at least moderately inconsistent with these data, within the context of LQ models. It is emphasized, however, that there is little direct information in these data regarding low-dose risks; the inferences here depend strongly on the link between low-dose and high-dose risks provided by the assumption of an LQ model. (author)

  17. How the negative and positive aspects of partner relationships affect the mental health of young married people.

    Science.gov (United States)

    Horwitz, A V; McLaughlin, J; White, H R

    1998-06-01

    The relationship between marriage and positive mental health is one of the most established findings in the stress literature. Few studies, however, examine the problematic as well as the supportive impacts of marriage on mental health. This paper uses a cohort of young adults who were sampled at 18, 21, or 24 years of age and resampled seven years later when they were married at 25, 28, or 31. It examines what factors are associated with the quality of marital relationships, the relative impact of and balance between negative and positive partner relationships on mental health, and sex differences in the determinants and outcomes of marital quality. The results indicate that the structural strains of parenthood and financial need and their interaction predict problematic and supportive spousal relationships and the difference in the levels of these two relationships. Problematic relationships with spouses have considerably stronger impacts than supportive relationships on depression. However, the difference between the amounts of supportive and problematic relationships with spouses has a greater impact on mental health than levels of either considered separately. Finally, relational quality has a greater impact on the mental health of wives than husbands. These findings indicate the importance of considering how marriage affects mental health in complex, rather than in straightforward, ways.

  18. Is the Relationship between Race and Continuous Positive Airway Pressure Adherence Mediated by Sleep Duration?

    Science.gov (United States)

    Billings, Martha E.; Rosen, Carol L.; Wang, Rui; Auckley, Dennis; Benca, Ruth; Foldvary-Schaefer, Nancy; Iber, Conrad; Zee, Phyllis; Redline, Susan; Kapur, Vishesh K.

    2013-01-01

    ://clinicaltrials.gov/show/NCT00642486. NIH clinical trials registry number: NCT00642486. Citation: Billings ME; Rosen CL; Wang R; Auckley D; Benca R; Foldvary-Schaefer N; Iber C; Zee P; Redline S; Kapur VK. Is the relationship between race and continuous positive airway pressure adherence mediated by sleep duration? SLEEP 2013;36(2):221-227. PMID:23372269

  19. Relationship between job stress, occupational position and job satisfaction using a brief job stress questionnaire (BJSQ).

    Science.gov (United States)

    Kawada, Tomoyuki; Otsuka, Toshiaki

    2011-01-01

    Subjects with higher occupational position are speculated to have higher ability to handle with stress, and they were less affected by job stress. This study focused on the relationship between job satisfaction and three sub-scales of a brief job stress questionnaire (BJSQ) related to workload. This self-administered questionnaire was distributed to 371 employees of a company, and all the workers sent back their responses. Among the 57 items graded on a 4-point Likert-type scale to measure job stressors, psycho-physical complaints, and support for workers, the authors studied the influence of quantitative and qualitative job overload (six items), job control (three items), and support port (six items). The job satisfaction score estimated on a 4-point Likert-type scale was also used in relation to job stress determined using a 15-item scale from the BJSQ based on demand-control-support model. Occupational positions were classified into directors, managers, and general workers, and the content of job was classified into clerical workers, skilled technicians, and unskilled manual workers. All the scales on job stress presented acceptable alpha coefficients reflecting high internal consistency (job demand: 0.855, job control: 0.644, and support: 0.878, respectively). Principal axis factor analysis was conducted, and three factors were extracted; support, job demand and job control. There was a significant difference in the mean score among four groups divided by the job satisfaction level as evaluated by Dunnett's multiple comparison, and members who were dissatisfied with their job showed a high job demand, limited job control, and poor support. The mean score of support for managers were significantly higher (lower support) than that for general workers. The logistic regression analysis revealed that job control and support contributed significantly to job satisfaction. In addition, unskilled manual workers showed significantly higher job dissatisfaction compared

  20. Expressions of positive emotion in women's college yearbook pictures and their relationship to personality and life outcomes across adulthood.

    Science.gov (United States)

    Harker, L; Keltner, D

    2001-01-01

    To test hypotheses about positive emotion, the authors examined the relationship of positive emotional expression in women's college pictures to personality, observer ratings, and life outcomes. Consistent with the notion that positive emotions help build personal resources, positive emotional expression correlated with the self-reported personality traits of affiliation, competence, and low negative emotionality across adulthood and predicted changes in competence and negative emotionality. Observers rated women displaying more positive emotion more favorably on several personality dimensions and expected interactions with them to be more rewarding; thus, demonstrating the beneficial social consequences of positive emotions. Finally, positive emotional expression predicted favorable outcomes in marriage and personal well-being up to 30 years later. Controlling for physical attractiveness and social desirability had little impact on these findings.

  1. Positive relationship between p42.3 gene and inflammation in chronic non-atrophic gastritis.

    Science.gov (United States)

    Chen, Ping; Cui, Yun; Fu, Qing Yan; Lu, You Yong; Fang, Jing Yuan; Chen, Xiao Yu

    2015-10-01

    Gastric cancer (GC) is a typical type of inflammation-related tumor. The p42.3 gene is shown to be highly expressed in GC, but its association with gastritis remains unknown. We aimed to explore the relationship between gastric inflammation and p42.3 gene in vitro and in vivo. Normal gastric epithelial cells (GES-1) were treated with Helicobacter pylori (H. pylori) and tumor necrosis factor (TNF)-α. Total cell mRNA and protein were extracted and collected, and polymerase chain reaction and Western blot were performed to determine the relative expression of p42.3 gene. In total, 291 biopsy samples from patients with chronic non-atrophic gastritis were collected and immunohistochemistry was used to measure the p42.3 protein expression. The association between p42.3 protein expression and the clinicopathological characteristics of these patients were analyzed. Both H. pylori and TNF-α significantly enhanced the p42.3 protein expression in GES-1 cells in a time and dose-dependent manner. In addition, p42.3 gene expression was positively associated with the severity of gastric mucosal inflammation and H. pylori infection (P = 0.000). Its expression was significantly more common in severe gastric inflammation and in H. pylori-infected cases. p42.3 gene expression is associated with gastric mucosal inflammation that can be upregulated by TNF-α and H. pylori infection. © 2015 Chinese Medical Association Shanghai Branch, Chinese Society of Gastroenterology, Renji Hospital Affiliated to Shanghai Jiaotong University School of Medicine and Wiley Publishing Asia Pty Ltd.

  2. Whole grain and refined grain consumption and the risk of type 2 diabetes: a systematic review and dose-response meta-analysis of cohort studies.

    Science.gov (United States)

    Aune, Dagfinn; Norat, Teresa; Romundstad, Pål; Vatten, Lars J

    2013-11-01

    Several studies have suggested a protective effect of intake of whole grains, but not refined grains on type 2 diabetes risk, but the dose-response relationship between different types of grains and type 2 diabetes has not been established. We conducted a systematic review and meta-analysis of prospective studies of grain intake and type 2 diabetes. We searched the PubMed database for studies of grain intake and risk of type 2 diabetes, up to June 5th, 2013. Summary relative risks were calculated using a random effects model. Sixteen cohort studies were included in the analyses. The summary relative risk per 3 servings per day was 0.68 (95% CI 0.58-0.81, I(2) = 82%, n = 10) for whole grains and 0.95 (95% CI 0.88-1.04, I(2) = 53%, n = 6) for refined grains. A nonlinear association was observed for whole grains, p nonlinearity cereals, wheat bran and brown rice, but these results were based on few studies, while white rice was associated with increased risk. Our meta-analysis suggests that a high whole grain intake, but not refined grains, is associated with reduced type 2 diabetes risk. However, a positive association with intake of white rice and inverse associations between several specific types of whole grains and type 2 diabetes warrant further investigations. Our results support public health recommendations to replace refined grains with whole grains and suggest that at least two servings of whole grains per day should be consumed to reduce type 2 diabetes risk.

  3. Nice to know you: Positive emotions, self-other overlap, and complex understanding in the formation of a new relationship.

    Science.gov (United States)

    Waugh, Christian E; Fredrickson, Barbara L

    2006-04-01

    Based on Fredrickson's ((1998). What good are positive emotions? Review of General Psychology, 2, 300-319.; (2001). The role of positive emotions in positive psychology: The broaden-and-build theory of positive emotions. American Psychologist, 56, 218-226) broaden-and-build theory and Aron and Aron's ((1986). Love as expansion of the self: Understanding attraction and satisfaction. New York: Hemisphere) self-expansion theory, it was hypothesized that positive emotions broaden people's feelings of self-other overlap in the beginning of a new relationship. In a prospective study of first-year college students, we found that, after 1 week in college, positive emotions predicted increased self-other overlap with new roommates, which in turn predicted a more complex understanding of the roommate. In addition, participants who experienced a high ratio of positive to negative emotions throughout the first month of college reported a greater increase in self-other overlap and complex understanding than participants with a low positivity ratio. Implications for the role of positive emotions in the formation of new relationships are discussed.

  4. Nice to know you: Positive emotions, self–other overlap, and complex understanding in the formation of a new relationship

    Science.gov (United States)

    WAUGH, CHRISTIAN E.; FREDRICKSON, BARBARA L.

    2007-01-01

    Based on Fredrickson's ((1998). What good are positive emotions? Review of General Psychology, 2, 300–319.; (2001). The role of positive emotions in positive psychology: The broaden-and-build theory of positive emotions. American Psychologist, 56, 218–226) broaden-and-build theory and Aron and Aron's ((1986). Love as expansion of the self: Understanding attraction and satisfaction. New York: Hemisphere) self-expansion theory, it was hypothesized that positive emotions broaden people's feelings of self–other overlap in the beginning of a new relationship. In a prospective study of first-year college students, we found that, after 1 week in college, positive emotions predicted increased self–other overlap with new roommates, which in turn predicted a more complex understanding of the roommate. In addition, participants who experienced a high ratio of positive to negative emotions throughout the first month of college reported a greater increase in self–other overlap and complex understanding than participants with a low positivity ratio. Implications for the role of positive emotions in the formation of new relationships are discussed. PMID:21691460

  5. Family-of-Origin Factors and Partner Violence in the Intimate Relationships of Gay Men Who Are HIV Positive

    Science.gov (United States)

    SEROVICH, JULIANNE M.

    2005-01-01

    This exploratory study examined the prevalence of intimate partner violence in a sample of gay men who are HIV positive. The concept of intergenerational transmission of violence, from family systems theory, provided the basis of this examination. It was hypothesized that men who had witnessed or experienced violence in their families of origin would be more likely to perpetrate or experience violence in their intimate relationships. Perpetration and receipt of abuse were assessed to provide a more comprehensive examination of these relationships. The results of this study indicated that psychological abuse was the most commonly reported form of violence in these relationships. The results also provided partial support for the hypothesized relationship between family-of-origin violence and subsequent violence in an intimate relationship. Implications for future research and intervention are discussed. PMID:15914700

  6. The Power of Positivity: Predictors of Relationship Satisfaction for Parents of Children with Autism Spectrum Disorder

    Science.gov (United States)

    Ekas, Naomi V.; Timmons, Lisa; Pruitt, Megan; Ghilain, Christine; Alessandri, Michael

    2015-01-01

    The current study uses the actor-partner interdependence model to examine the predictors of relationship satisfaction for mothers and fathers of children with autism spectrum disorder. Sixty-seven couples completed measures of optimism, benefit finding, coping strategies, social support, and relationship satisfaction. Results indicated that…

  7. Differentiating Three Conceptualisations of the Relationship between Positive Development and Psychopathology during the Transition to Adulthood

    Science.gov (United States)

    O'Connor, Meredith; Sanson, Ann; Hawkins, Mary T.; Toumbourou, John W.; Letcher, Primrose; Frydenberg, Erica

    2011-01-01

    The transition to adulthood is characterised by both great potential for positive change and a relatively high incidence of problem outcomes. A multidimensional model of positive development during the transition to adulthood (at 19-20 years) has recently been proposed. However, an unresolved question regarding the nature of positive development…

  8. Systematic overview of preoperative (neoadjuvant) chemoradiotherapy trials in oesophageal cancer: Evidence of a radiation and chemotherapy dose response

    International Nuclear Information System (INIS)

    Geh, J. Ian; Bond, Simon J.; Bentzen, Soren M.; Glynne-Jones, Robert

    2006-01-01

    Background and purpose: Numerous trials have shown that pathological complete response (pCR) following preoperative chemoradiotherapy (CRT) and surgery for oesophageal cancer is associated with improved survival. However, different radiotherapy doses and fractionations and chemotherapy drugs, doses and scheduling were used, which may account for the differences in observed pCR and survival rates. A dose-response relationship may exist between radiotherapy and chemotherapy dose and pCR. Patients and methods: Trials using a single radiotherapy and chemotherapy regimen (5FU, cisplatin or mitomycin C-based) and providing information on patient numbers, age, resection and pCR rates were eligible. The endpoint used was pCR and the covariates analysed were prescribed radiotherapy dose, radiotherapy dosexdose per fraction, radiotherapy treatment time, prescribed chemotherapy (5FU, cisplatin and mitomycin C) dose and median age of patients within the trial. The model used was a multivariate logistic regression. Results: Twenty-six trials were included (1335 patients) in which 311 patients (24%) achieved pCR. The probability of pCR improved with increasing dose of radiotherapy (P=0.006), 5FU (P=0.003) and cisplatin (P=0.018). Increasing radiotherapy treatment time (P=0.035) and increasing median age (P=0.019) reduced the probability of pCR. The estimated α/β ratio of oesophageal cancer was 4.9 Gy (95% confidence interval (CI) 1.5-17 Gy) and the estimated radiotherapy dose lost per day was 0.59 Gy (95% CI 0.18-0.99 Gy). One gram per square metre of 5FU was estimated to be equivalent to 1.9 Gy (95% CI 0.8-5.2 Gy) of radiation and 100 mg/m 2 of cisplatin was estimated to be equivalent to 7.2 Gy (95% CI 2.1-28 Gy). Mitomycin C dose did not appear to influence pCR rates (P=0.60). Conclusions: There was evidence of a dose-response relationship between increasing protocol prescribed radiotherapy, 5FU and cisplatin dose and pCR. Additional significant factors were radiotherapy

  9. Relationships between meaning in life, social and achievement events, and positive and negative affect in daily life.

    Science.gov (United States)

    Machell, Kyla A; Kashdan, Todd B; Short, Jerome L; Nezlek, John B

    2015-06-01

    Research on meaning in life has generally focused on global meaning judgments. This study examined how people's daily experiences, represented by events that occur in daily life, influence their perceived sense of meaning on a daily basis. One hundred sixty-two college students completed daily reports for 2 weeks. We examined the relationships among daily social and achievement events, daily positive and negative affect, and daily meaning in life. In addition, we tested the possible moderating influence of depressive symptoms on these relationships. Positive daily social and achievement events were related to greater daily meaning, above and beyond the contributions of daily positive and negative affect. Negative social and achievement events were related to less daily meaning, and negative achievement events covaried with daily meaning above and beyond positive and negative affect. Depression moderated the relationships between positive events and meaning, such that people who reported more depressive symptoms had greater increases in daily meaning in response to positive social and achievement events than individuals who reported fewer symptoms. These findings suggest the important role that daily events may play in fluctuations in people's affective experiences and sense of meaning in life. © 2014 Wiley Periodicals, Inc.

  10. Population variability in biological adaptive responses to DNA damage and the shapes of carcinogen dose-response curves

    International Nuclear Information System (INIS)

    Conolly, Rory B.; Gaylor, David W.; Lutz, Werner K.

    2005-01-01

    Carcinogen dose-response curves for both ionizing radiation and chemicals are typically assumed to be linear at environmentally relevant doses. This assumption is used to ensure protection of the public health in the absence of relevant dose-response data. A theoretical justification for the assumption has been provided by the argument that low dose linearity is expected when an exogenous agent adds to an ongoing endogenous process. Here, we use computational modeling to evaluate (1) how two biological adaptive processes, induction of DNA repair and cell cycle checkpoint control, may affect the shapes of dose-response curves for DNA-damaging carcinogens and (2) how the resulting dose-response behaviors may vary within a population. Each model incorporating an adaptive process was capable of generating not only monotonic dose-responses but also nonmonotonic (J-shaped) and threshold responses. Monte Carlo analysis suggested that all these dose-response behaviors could coexist within a population, as the spectrum of qualitative differences arose from quantitative changes in parameter values. While this analysis is largely theoretical, it suggests that (a) accurate prediction of the qualitative form of the dose-response requires a quantitative understanding of the mechanism (b) significant uncertainty is associated with human health risk prediction in the absence of such quantitative understanding and (c) a stronger experimental and regulatory focus on biological mechanisms and interindividual variability would allow flexibility in regulatory treatment of environmental carcinogens without compromising human health

  11. Social Relationships and Health: Is Feeling Positive, Negative, or Both (Ambivalent) about your Social Ties Related to Telomeres?

    Science.gov (United States)

    Uchino, Bert N.; Cawthon, Richard M.; Smith, Timothy W.; Light, Kathleen C.; McKenzie, Justin; Carlisle, McKenzie; Gunn, Heather; Birmingham, Wendy; Bowen, Kimberly

    2012-01-01

    Objective The quality of one’s personal relationships has been linked to morbidity and mortality across different diseases. As a result, it is important to examine more integrative mechanisms that might link relationships across diverse physical health outcomes. In this study, we examine associations between relationships and telomeres which predict general disease risk. These questions are pursued in the context of a more comprehensive model of relationships that highlights the importance of jointly considering positive and negative aspects of social ties. Method 136 individuals from a community sample (ages 48 to 77) completed the social relationships index which allows a determination of relationships that differ in their positive and negative substrates (i.e., ambivalent, supportive, aversive, indifferent). Telomere length was determined from peripheral blood mononuclear cells via quantitative PCR. Results Participants who had a higher number of ambivalent ties in their social networks evidenced shorter telomeres. These results were independent of other relationships types (e.g., supportive), as well as standard control variables (e.g., age, health behaviors, medication use). Gender moderated the links between ambivalent ties and telomere length with these associations seen primarily in women. Follow-up analyses revealed that the links between ambivalent ties and telomeres were primarily due to friendships, parents, and social acquaintances. Conclusions Consistent with epidemiological findings, these data highlight a novel and integrative biological mechanism by which social ties may impact health across diseases, and further suggests the importance of incorporating both positivity and negativity in the study of specific relationships and physical health. PMID:22229928

  12. [Relationship between serum level of uric acid and benign paroxysmal positional vertigo].

    Science.gov (United States)

    Yuan, Junliang; Chen, Yili; Chen, Yudan; Niu, Shiqin; Li, Shujuan; Dong, Qian; Hu, Wenli

    2015-02-03

    To confirm the possible relationships between serum level of uric acid (UA) and benign paroxysmal positional vertigo (BPPV). A total of 87 patients with BPPV and 36 age- and gender-matched control subjects were recruited from our hospital between July 1, 2013 and July 1, 2014. All patients underwent a complete audio-vestibular test battery, such as Dix-Hallpike maneuver for posterior semicircular canal and supine roll test for horizontal semicircular canal. All risk factors such as the histories of heart and cerebral vascular diseases, and routine hematological and biochemical analyses were analyzed between two groups. No significant inter-group differences existed in age, gender, histories of hypertension, diabetes mellitus, hyperlipidemia, coronary heart disease, smoking or drinking (P > 0.05). No significant differences existed between systolic blood pressure, diastolic blood pressure, ejection fraction, whole blood count, lipid profile, homocysteine, prealbumin and blood urea nitrogen in patients with BPPV compared with controls (P >0. 05). However, the values of UA (267 ± 86 vs 325 ± 75) µmol/L, hemoglobin ale (5.6 ± 1. 4 vs 6.5 ± 1. 0)%, albumin (36 ± 4 vs 40 ± 4) g/L and creatinine (72 ± 20 vs 81 ± 22) µmol/L were much lower in patients with BPPV versus controls (P < 0. 05). According to multiple Logistic regression model, the lower levels of hemoglobin ale and albumin were independently associated with BPPV (P <0. 05) with the odds ratio of 1. 473 (95% CI 1. 066 - 2. 037) and 1. 162 (95% CI 1. 025 - 1. 318), respectively. However, the level of UA was not independently correlated with the occurrence of BPPV [OR = 1. 005 (95% CI 1. 000 - 1. 011), P =0. 063]. The lower levels of hemoglobin alc and albumin are independently associated with BPPV. Although the value of UA is lower in patients with BPPV versus controls, it is not an independent risk factor for BPPV. Due to limited patient data, further studies are needed to clarify the association in a

  13. Radical prostatectomy and positive surgical margins: relationship with prostate cancer outcome

    Directory of Open Access Journals (Sweden)

    Ricardo L. R. Felts de La Roca

    2014-06-01

    Full Text Available Introduction Positive surgical margins (PSMs are an adverse factor that may predict a worse outcome in patients submitted to radical prostatectomy (RP. However, not all of these cases will evolve to biochemical (BCR or clinical (CR recurrence, therefore relationship between PSMs and these recurrent events has to be correlated with other clinical and pathologic findings to indicate complementary treatment for selected patients. Materials and Methods Of 1250 patients submitted to open retropubic radical prostatectomy (RRP, between March 1991 and June 2008, the outcome of 161 patients with PSMs and of 67 without PSMs as a control group, comprising a total of 228 cases were retrospectively reviewed. A minimum follow-up time of 2 years after surgery was considered. BCR was determined when PSA ≥ 0.2ng/mL. CR was determined whenever there was clinical evidence of tumor. Chi-square test was used to correlate clinical and pathologic variables with PSMs. Time interval to biochemical recurrence was analyzed by the Kaplan-Meier product limit analysis using the log-rank test for comparison between groups. Univariate and multivariate Cox stepwise logistic regression models were used to identify significant predictors of risk of shorter intervals to BCR. Results Prostate circumference margin was the most common site with 78 cases (48.44%. Regarding the outcome of 228 cases from both groups, BCR occurred in 68 patients (29.82%, and CR in 10 (4.38%. Univariate analysis showed statistically significant associations (p < 0.001 between presence of PSMs with BCR, but not with CR (p = 0.05. At follow-up of the 161 patients with PSMs, only 61(37.8% presented BCR, while 100 (62.8% did not. BCR correlated with pathologic stage; Gleason score; preoperative PSA; tumor volume in the specimen; capsular and perineural invasion; presence and number of PSMs. CR correlated only with angiolymphatic invasion and Gleason score. Considering univariate analysis of clinical and

  14. Relationship between vertebral artery blood flow in different head positions and vertigo.

    Science.gov (United States)

    Araz Server, Ela; Edizer, Deniz Tuna; Yiğit, Özgür; Yasak, Ahmet Görkem; Erdim, Çağrı

    2018-01-01

    To identify the vertebral artery blood flow in different head positions in patients with positional vertigo with no specific diagnosis. Patients with history of vestibular symptoms associated with changes in head position were enrolled into the study. Healthy volunteers were evaluated as control group. Doppler ultrasonography examination of the cervical segment of the vertebral arteries was performed under three different head positions: (i) supine position, (ii) head hyperextended and rotated to the right side and (iii) head hyperextended and rotated to the left side. In the study group, right and left vertebral artery blood flow was significantly lower in the ipsilateral hyperextended position compared to standard supine position (respectively p = .014; p = .001), but did not differ significantly when compared between the standard supine and contralateral hyperextended positions (respectively = .959; p = .669). In the control group, left and right vertebral artery blood flow did not differ significantly when the head was hyperextended to the right or left sides compared to standard supine position (p > .05). Our data demonstrated that the etiology of vestibular complaints in patients with undiagnosed positional vertigo might be related to impairment in vertebral artery blood flow according to head positions.

  15. Leading from the Centre: A Comprehensive Examination of the Relationship between Central Playing Positions and Leadership in Sport

    Science.gov (United States)

    Haslam, S. Alexander; Mallett, Cliff J.; Steffens, Niklas K.; Peters, Kim; Boen, Filip

    2016-01-01

    Research aims The present article provides a comprehensive examination of the relationship between playing position and leadership in sport. More particularly, it explores links between leadership and a player’s interactional centrality—defined as the degree to which their playing position provides opportunities for interaction with other team members. This article examines this relationship across different leadership roles, team sex, and performance levels. Results Study 1 (N = 4443) shows that athlete leaders (and the task and motivational leader in particular) are more likely than other team members to occupy interactionally central positions in a team. Players with high interactional centrality were also perceived to be better leaders than those with low interactional centrality. Study 2 (N = 308) established this link for leadership in general, while Study 3 (N = 267) and Study 4 (N = 776) revealed that the same was true for task, motivational, and external leadership. This relationship is attenuated in sports where an interactionally central position confers limited interactional advantages. In other words, the observed patterns were strongest in sports that are played on a large field with relatively fixed positions (e.g., soccer), while being weaker in sports that are played on a smaller field where players switch positions dynamically (e.g., basketball, ice hockey). Beyond this, the pattern is broadly consistent across different sports, different sexes, and different levels of skill. Conclusions The observed patterns are consistent with the idea that positions that are interactionally central afford players greater opportunities to do leadership—either through communication or through action. Significantly too, they also provide a basis for them to be seen to do leadership by others on their team. Thus while it is often stated that “leadership is an action, not a position,” it is nevertheless the case that, when it comes to performing that

  16. The Mediation Effect of School Satisfaction in the Relationship between Teacher Support, Positive Affect and Life Satisfaction in Adolescents

    Science.gov (United States)

    Telef, Bülent Baki; Arslan, Gökmen; Mert, Abdullah; Kalafat, Sezai

    2015-01-01

    The aim of this study is to examine the relationships among teacher support, positive emotions, school satisfaction and life satisfaction in adolescences. The study had the participation of 344 adolescents from different socio-economic levels studying in the sixth, seventh and eighth grades of three public middle schools in the province of…

  17. The Relationship between Positive Development and Psychopathology during the Transition to Adulthood: A Person-Centred Approach

    Science.gov (United States)

    O'Connor, Meredith; Sanson, Ann; Hawkins, Mary T.; Olsson, Craig; Frydenberg, Erica; Toumbourou, John W.; Letcher, Primrose

    2012-01-01

    The transition to adulthood is characterised by potential for both positive development and problem outcomes such as psychopathology, yet little is known about relationships between the two. Given the diversity of pathways observed during this transition period, there is likely to be significant heterogeneity in young people's experiences of these…

  18. Positive and Negative Affectivity as Mediator and Moderator of the Relationship between Optimism and Life Satisfaction in Turkish University Students

    Science.gov (United States)

    Kapikiran, Necla Acun

    2012-01-01

    The main purpose of this study is to examine the mediator and moderator role of positive and negative affectivity variables on the relationship between optimism and life satisfaction in university students. 397 university students, ranging in age from 18 to 27 (M = 20.98), attending different departments of the Faculty of Education, at Pamukkale…

  19. The Association Between Positive Relationships with Adults and Suicide-Attempt Resilience in American Indian Youth in New Mexico.

    Science.gov (United States)

    FitzGerald, Courtney A; Fullerton, Lynne; Green, Dan; Hall, Meryn; Peñaloza, Linda J

    2017-01-01

    This study examined the 2013 New Mexico Youth Risk and Resiliency Survey (NM-YRRS) to determine whether cultural connectedness and positive relationships with adults protected against suicide attempts among American Indian and Alaska Native (AI/AN) youth and whether these relationships differed by gender. The sample included 2,794 AI/AN students in grades 9 to 12 who answered the question about past-year suicide attempts. Protective factor variables tested included relationships with adults at home, school, and the community. The language spoken at home was used as a proxy measure for cultural connectedness. Positive relationships with adults were negatively associated with the prevalence of past-year suicide attempts in bivariate analysis. However, language spoken at home was not associated with the prevalence of suicide attempts. Multivariate analysis showed that among girls, relationships with adults at home, at school, and in the community were independently associated with lower suicide-attempt prevalence. Among boys, only relationships with adults at home showed such an association. These results have important implications for the direction of future research about protective factors associated with AI/AN youth suicide risk as well as in the design of suicide intervention and prevention programs.

  20. Dose-response curves for fish MFO induction: How do we interpret different maxima and slopes?

    International Nuclear Information System (INIS)

    Parrott, J.L.

    1995-01-01

    Induction of hepatic mixed function oxygenase (MFO) activity has been useful for screening effluents from pulp mills and oil refineries. Effluents and pure compounds can be assessed by direct fish exposure or by concentration with semipermeable membrane devices (SPMDs) and by measuring MFO in fish liver cell lines exposed to SPMD extracts. In these experiments, both fish and fish cells showed differences in slopes of dose-response curves, and in the maximal ethoxyresorufin-O-deethylase (EROD) activity. For example, TCDD elicits an EROD maxima of over 500 pmol/mg/min in PLHC-1 (Poeciliopsis lucida hepatocellular carcinoma cell line), while pulp mill and oil refinery effluent extracts showed maxima of 40 to 200 pmol/mg/min. Substituted phenanthrenes caused induction maxima of 100 pmol/mg/min. Similarly, in rainbow trout in vivo, TCDD and other chlorinated dioxins and furans induced up to 500 pmol/mg/min, whereas pulp mill and refinery effluents and substituted phenanthrenes produced EROD maxima of up to 100 pmol/mg/min. Differences in the slopes of dose-response curves were also common. In the current assessment of potencies, these diverse response curves are boiled-down to one number, the EC50 or other threshold-type of concentration. Comparisons of EC50s cannot express these differences and instead, ignore them. However, the authors realize there must be a better approach that takes into account these large differences in dose-response curve shape, slope and maxima. Interaction and discussions with modelers in the session will allow them to discuss various approaches to expressing the potencies of MFO inducers in fish

  1. Flow characterization and patch clamp dose responses using jet microfluidics in a tubeless microfluidic device.

    Science.gov (United States)

    Resto, Pedro J; Bhat, Abhishek; Stava, Eric; Lor, Chong; Merriam, Elliot; Diaz-Rivera, Ruben E; Pearce, Robert; Blick, Robert; Williams, Justin C

    2017-11-01

    Surface tension passive pumping is a way to actuate flow without the need for pumps, tubing or valves by using the pressure inside small drop to move liquid via a microfluidic channel. These types of tubeless devices have typically been used in cell biology. Herein we present the use of tubeless devices as a fluid exchange platform for patch clamp electrophysiology. Inertia from high-speed droplets and jets is used to create flow and perform on-the-fly mixing of solutions. These are then flowed over GABA transfected HEK cells under patch in order to perform a dose response analysis. TIRF imaging and electrical recordings are used to study the fluid exchange properties of the microfluidic device, resulting in 0-90% fluid exchange times of hundreds of milliseconds. COMSOL is used to model flow and fluid exchange within the device. Patch-clamping experiments show the ability to use high-speed passive pumping and its derivatives for studying peak dose responses, but not for studying ion channel kinetics. Our system results in fluid exchange times slower than when using a standard 12-barrel application system and is not as stable as traditional methods, but it offers a new platform with added functionality. Surface tension passive pumping and tubeless devices can be used in a limited fashion for electrophysiology. Users may obtain peak dose responses but the system, in its current form, is not capable of fluid exchange fast enough to study the kinetics of most ion channels. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Determination of tolerance dose uncertainties and optimal design of dose response experiments with small animal numbers

    International Nuclear Information System (INIS)

    Karger, C.P.; Hartmann, G.H.

    2001-01-01

    Background: Dose response experiments aim to determine the complication probability as a function of dose. Adjusting the parameters of the frequently used dose response model P(D)=1/[1+(D 50 /D) k ] to the experimental data, 2 intuitive quantities are obtained: The tolerance dose D 50 and the slope parameter k. For mathematical reasons, however, standard statistic software uses a different set of parameters. Therefore, the resulting fit parameters of the statistic software as well as their standard errors have to be transformed to obtain D 50 and k as well as their standard errors. Material and Methods: The influence of the number of dose levels on the uncertainty of the fit parameters is studied by a simulation for a fixed number of animals. For experiments with small animal numbers, statistical artifacts may prevent the determination of the standard errors of the fit parameters. Consequences on the design of dose response experiments are investigated. Results: Explicit formulas are presented, which allow to calculate the parameters D 50 and k as well as their standard errors from the output of standard statistic software. The simulation shows, that the standard errors of the resulting parameters are independent of the number of dose levels, as long as the total number of animals involved in the experiment, remains constant. Conclusion: Statistical artifacts in experiments containing small animal numbers may be prevented by an adequate design of the experiment. For this, it is suggested to select a higher number of dose levels, rather than using a higher number of animals per dose level. (orig.) [de

  3. Regulation of operant oral ethanol self-administration: a dose-response curve study in rats.

    Science.gov (United States)

    Carnicella, Sebastien; Yowell, Quinn V; Ron, Dorit

    2011-01-01

    Oral ethanol self-administration procedures in rats are useful preclinical tools for the evaluation of potential new pharmacotherapies as well as for the investigation into the etiology of alcohol abuse disorders and addiction. Determination of the effects of a potential treatment on a full ethanol dose-response curve should be essential to predict its clinical efficacy. Unfortunately, this approach has not been fully explored because of the aversive taste reaction to moderate to high doses of ethanol, which may interfere with consumption. In this study, we set out to determine whether a meaningful dose-response curve for oral ethanol self-administration can be obtained in rats. Long-Evans rats were trained to self-administer a 20% ethanol solution in an operant procedure following a history of excessive voluntary ethanol intake. After stabilization of ethanol self-administration, the concentration of the solution was varied from 2.5 to 60% (v/v), and operant and drinking behaviors, as well as blood ethanol concentration (BEC), were evaluated following the self-administration of a 20, 40, and 60% ethanol solution. Varying the concentration of ethanol from 2.5 to 60% after the development of excessive ethanol consumption led to a typical inverted U-shaped dose-response curve. Importantly, rats adapted their level and pattern of responding to changes in ethanol concentration to obtain a constant level of intake and BEC, suggesting that their operant behavior is mainly driven by the motivation to obtain a specific pharmacological effect of ethanol. This procedure can be a useful and straightforward tool for the evaluation of the effects of new potential pharmacotherapies for the treatment of alcohol abuse disorders. Copyright © 2010 by the Research Society on Alcoholism.

  4. Effect of Enamel Caries Lesion Baseline Severity on Fluoride Dose-Response

    Directory of Open Access Journals (Sweden)

    Frank Lippert

    2017-01-01

    Full Text Available This study aimed to investigate the effect of enamel caries lesion baseline severity on fluoride dose-response under pH cycling conditions. Early caries lesions were created in human enamel specimens at four different severities (8, 16, 24, and 36 h. Lesions were allocated to treatment groups (0, 83, and 367 ppm fluoride as sodium fluoride based on Vickers surface microhardness (VHN and pH cycled for 5 d. The cycling model comprised 3 × 1 min fluoride treatments sandwiched between 2 × 60 min demineralization challenges with specimens stored in artificial saliva in between. VHN was measured again and changes versus lesion baseline were calculated (ΔVHN. Data were analyzed using two-way ANOVA (p<0.05. Increased demineralization times led to increased surface softening. The lesion severity×fluoride concentration interaction was significant (p<0.001. Fluoride dose-response was observed in all groups. Lesions initially demineralized for 16 and 8 h showed similar overall rehardening (ΔVHN and more than 24 and 36 h lesions, which were similar. The 8 h lesions showed the greatest fluoride response differential (367 versus 0 ppm F which diminished with increasing lesion baseline severity. The extent of rehardening as a result of the 0 ppm F treatment increased with increasing lesion baseline severity, whereas it decreased for the fluoride treatments. In conclusion, lesion baseline severity impacts the extent of the fluoride dose-response.

  5. Physical activity and motor competence present a positive reciprocal longitudinal relationship across childhood and early adolescence

    DEFF Research Database (Denmark)

    Lima, Rodrigo A.; Pfeiffer, Karin; Larsen, Lisbeth R.

    2017-01-01

    Background: The current study evaluated the reciprocal longitudinal relationship between physical activity (PA) and motor competence (MC) and the potential mediation of cardiorespiratory endurance across 7 years. Methods: This was a 7-year longitudinal study, the Copenhagen School Child Intervent......Background: The current study evaluated the reciprocal longitudinal relationship between physical activity (PA) and motor competence (MC) and the potential mediation of cardiorespiratory endurance across 7 years. Methods: This was a 7-year longitudinal study, the Copenhagen School Child...

  6. Paradoxical Relationship between the Amount of Negative eWOM Messages and Positive Consumer Attitude

    OpenAIRE

    Mai Kikumori; Akinori Ono

    2013-01-01

    Most research has shown that positive electric word-of-mouth (e-WOM) has positive effects, while negative e-WOM has negative effects on consumer attitude towards a product. However, negative e-WOM may have positive impacts rather than negative impacts. Using ANOVA in three experiments, this study found that negative e-WOM can have a positive impact on consumer attitude under some conditions, including when the e-WOM is in regard to hedonic products, when expert consumers read attribute-centri...

  7. Dose-response functions and corrosion mapping for a small geographical area

    International Nuclear Information System (INIS)

    Haagenrud, S.E.; Henriksen, J.F.; Gram, F.

    1985-01-01

    Detailed corrosion and environmental measurements have been used to develop dose response (D/R) functions for carbon steel, zinc, copper, and aluminum for a 26 x 31 km urban/rural area with approximately homogeneous climate. The D/R functions, expressed in terms of SO 2 and time of wetness, were of the same type for all four metals. The SO 2 contribution to the total corrosion dominates in the centers of towns and around an industrial plant. Corrosion maps for the whole area were established

  8. Similarity criterion analysis of dose-response curves in biological assay and radioimmunoassay of hormones

    International Nuclear Information System (INIS)

    Cristakou, H.D.

    1983-01-01

    The difficulties involved in the control of biological and radioimmunological assay systems, and in the maintenance of standard, as well as, the usual heterogeneity of assayed samples require some evidence of similarity between the dose-response curves obtained with the standard and the sample. Nowadays the parallelism test is used to provide such evidence. However, some indications of non-normal errors distribution, such as the presence of out layers, render the parallelism test both conceptually implausible and statistically inefficient. In such a manner we suggest the non-parametric 'frequencial' test as a more sounding option. (author)

  9. Dose Response Model of Biological Reaction to Low Dose Rate Gamma Radiation

    International Nuclear Information System (INIS)

    Magae, J.; Furikawa, C.; Hoshi, Y.; Kawakami, Y.; Ogata, H.

    2004-01-01

    It is necessary to use reproducible and stable indicators to evaluate biological responses to long term irradiation at low dose-rate. They should be simple and quantitative enough to produce the results statistically accurate, because we have to analyze the subtle changes of biological responses around background level at low dose. For these purposes we chose micronucleus formation of U2OS, a human osteosarcoma cell line, as indicators of biological responses. Cells were exposed to gamma ray in irradiation rom bearing 50,000 Ci 60Co. After irradiation, they were cultured for 24 h in the presence of cytochalasin B to block cytokinesis, and cytoplasm and nucleus were stained with DAPI and prospidium iodide, respectively. the number of binuclear cells bearing micronuclei was counted under a fluorescence microscope. Dose rate in the irradiation room was measured with PLD. Dose response of PLD is linear between 1 mGy to 10 Gy, and standard deviation of triplicate count was several percent of mean value. We fitted statistically dose response curves to the data, and they were plotted on the coordinate of linearly scale response and dose. The results followed to the straight line passing through the origin of the coordinate axes between 0.1-5 Gy, and dose and does rate effectiveness factor (DDREF) was less than 2 when cells were irradiated for 1-10 min. Difference of the percent binuclear cells bearing micronucleus between irradiated cells and control cells was not statistically significant at the dose above 0.1 Gy when 5,000 binuclear cells were analyzed. In contrast, dose response curves never followed LNT, when cells were irradiated for 7 to 124 days. Difference of the percent binuclear cells bearing micronucleus between irradiated cells and control cells was not statistically significant at the dose below 6 Gy, when cells were continuously irradiated for 124 days. These results suggest that dose response curve of biological reaction is remarkably affected by exposure

  10. The affective tie that binds: Examining the contribution of positive emotions and anxiety to relationship formation in social anxiety disorder.

    Science.gov (United States)

    Taylor, Charles T; Pearlstein, Sarah L; Stein, Murray B

    2017-06-01

    Individuals with social anxiety disorder (SAD) have difficulty forming social relationships. The prevailing clinical perspective is that negative emotions such as anxiety inhibit one's capacity to develop satisfying social connections. However, empirical findings from social psychology and affective neuroscience suggest that positive emotional experiences are fundamental to establishing new social bonds. To reconcile these perspectives, we collected repeated measurements of anxiety, positive emotions (pleasantness), and connectedness over the course of a controlled relationship formation encounter in 56 participants diagnosed with SAD (64% female; M age =23.3, SD=4.7). Participants experienced both increases in positive emotions and decreases in anxiety throughout the interaction. Change in positive emotions was the most robust predictor of subsequent increases in connectedness, as well as a greater desire to engage one's partner in future social activities, above and beyond reductions in anxiety (medium to large sized effects). Those findings suggest that anxiety-based models alone may not fully explain difficulties in relationship formation in SAD, and underscore the potential value of considering positive emotional experiences in conceptual and treatment models of SAD. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. The Relationship between Positive Well-Being and Academic Assessment: Results from a Prospective Study on Dental Students

    Directory of Open Access Journals (Sweden)

    Cristina Teodora Preoteasa

    2016-01-01

    Full Text Available Background. Presumably, the academic stress that builds throughout the academic year has a negative effect on dental students’ psychological well-being and may have a relationship with academic performance. This research aimed to analyse the variation of positive well-being in second-year dental students, across the academic semester, in relation to consecutive examinations as part of academic assessment system (1 and to observe the relationship between academic performance during semester evaluation period and dental students’ positive well-being (2. Methods. A prospective study was conducted on second-year dental students, data on positive well-being being collected with WHO-Five Well-Being Index (WHO-5, at the beginning of the semester and after three consecutive mandatory examinations. Results. One hundred and forty-six dental students were included (77% response rate. Repeated ANOVA showed a significant progressive decline of positive well-being over the semester, which was clinically significant for an important part of them. Students who performed better in the semester evaluation period registered higher well-being levels at the beginning of the semester but a more pronounced decline of it until the semester evaluation period. Conclusion. Based on this research, a relationship between positive well-being, academic assessments, and academic performance is suggested, when evaluating them in a prospective frame.

  12. Authors' financial relationships with the food and beverage industry and their published positions on the fat substitute olestra.

    Science.gov (United States)

    Levine, Jane; Gussow, Joan Dye; Hastings, Diane; Eccher, Amy

    2003-04-01

    This study examined the association between authors' published positions on the safety and efficacy in assisting with weight loss of the Procter & Gamble (P&G) fat substitute olestra and their financial relationships with the food and beverage industry. Journal articles about olestra, and their authors, were classified as supportive, critical, or neutral with respect to its use. Authors not known to have industry affiliations were surveyed about their financial relationships. Supportive authors were significantly more likely than critical or neutral authors to have financial relationships with P&G (80% vs 11% and 21%, respectively; P <.0001). All authors disclosing an affiliation with P&G were supportive. Because authors' published opinions were associated with their financial relationships, obtaining noncommercial funding may be more essential to maintaining objectivity than disclosing personal financial interests.

  13. Authors’ Financial Relationships With the Food and Beverage Industry and Their Published Positions on the Fat Substitute Olestra

    Science.gov (United States)

    Levine, Jane; Gussow, Joan Dye; Hastings, Diane; Eccher, Amy

    2003-01-01

    Objectives. This study examined the association between authors’ published positions on the safety and efficacy in assisting with weight loss of the Procter & Gamble (P&G) fat substitute olestra and their financial relationships with the food and beverage industry. Methods. Journal articles about olestra, and their authors, were classified as supportive, critical, or neutral with respect to its use. Authors not known to have industry affiliations were surveyed about their financial relationships. Results. Supportive authors were significantly more likely than critical or neutral authors to have financial relationships with P&G (80% vs 11% and 21%, respectively; P < .0001). All authors disclosing an affiliation with P&G were supportive. Conclusions. Because authors’ published opinions were associated with their financial relationships, obtaining noncommercial funding may be more essential to maintaining objectivity than disclosing personal financial interests. PMID:12660215

  14. Positive Psychology Course and Its Relationship to Well-Being, Depression, and Stress

    Science.gov (United States)

    Goodmon, Leilani B.; Middleditch, Ashlea M.; Childs, Bethany; Pietrasiuk, Stacey E.

    2016-01-01

    The purpose of this study was to determine the influence of a positive psychology course on student well-being, depressive symptoms, and stress in a repeated measure, nonequivalent control design. As hypothesized, the positive psychology students reported higher overall happiness, life satisfaction, routes to happiness, and lower depressive…

  15. Positive and negative affect mediate the bidirectional relationship between emotional processing and symptom severity and impact in irritable bowel syndrome.

    Science.gov (United States)

    Sibelli, Alice; Chalder, Trudie; Everitt, Hazel; Chilcot, Joseph; Moss-Morris, Rona

    2018-02-01

    Individuals with IBS report higher levels of psychological distress compared to healthy controls. Distress has been associated with emotional processing difficulties but studies have not explored how the relationship between distress and emotional processing affects IBS. There is little research on the role of positive affect (PA) in IBS. (a) If difficulties in self-reported emotional processing are associated with affect and IBS measures (i.e., symptom severity, interference in life roles) (b1) If affect mediates the relationship between emotional processing and IBS measures (b2) Alternative model: if affect mediates the relationship between IBS and emotional processing (c) If PA moderates the relationship between distress and IBS. Participants with a confirmed diagnosis of IBS (n=558) completed a questionnaire including measures of emotional processing (i.e., unhelpful beliefs about negative emotions, impoverished emotional experience), distress, PA, and IBS symptoms/interference. Mediation and moderation analyses were conducted with Maximum Likelihood Estimation. Distress and PA mediated or partly mediated the relationship between unhelpful beliefs about negative emotions/impoverished emotional experience and both IBS measures. The alternative models were also valid, suggesting a two-way relationship between emotional processing and IBS through affect. PA did not moderate the relationship between distress and IBS. Future interventions in IBS may benefit from not only targeting the management of physical symptoms and their daily impact but also aspects related to the experience of both negative and positive affect, and the acceptance and expression of negative emotions. Longitudinal studies are needed to confirm causal relationships within the explored models. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Impact of DNA repair on the dose-response of colorectal cancer formation induced by dietary carcinogens.