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PubMed2005

Pharmacokinetics of BAY 59-7939--an oral, direct Factor Xa inhibitor--in rats and dogs.

The pharmacokinetics of BAY 59-7939 - a novel, oral, direct Factor Xa inhibitor - were investigated in rats and dogs in support of preclinical safety studies and clinical development. BAY 59-7939 was rapidly absorbed after oral dosing, with an absolute bioavailability of 57-66% in rats, and 60-86% in dogs. Plasma pharmacokinetics of BAY 59-7939 were linear across the investigated dose range (1-10 mg kg(-1) in rats, 0.3-3 mg kg(-1) in dogs). Plasma clearance was low: 0.4 l kg(-1) h(-1) in rats and 0.3 l kg(-1) h(-1) in dogs; volume of distribution (V(ss)) was moderate: 0.3 l kg(-1) in rats, and 0.4 l kg(-1) in dogs. The elimination half-life after oral administration was short in both species (0.9-2.3 h). Whole-body autoradiography showed moderate tissue affinity. No retention or small volume enrichments of BAY 59-7939-related radioactivity were observed. The plasma-protein binding of BAY 59-7939 was high, species dependent and fully reversible. BAY 59-7939 was rapidly excreted in rats and dogs, and was not irreversibly retained. A dual mode of excretion (biliary/faecal and renal) was observed. In summary, BAY 59-7939 had a favourable, predictable pharmacokinetic profile, with high oral bioavailability and a dual route of excretion.

Administration, Oral↗
PubMed1989

(-)-Bay K 8644 liberates a contractant factor from the endothelium of the rat aorta.

The contractile activity of (-)-Bay k 8644 was assessed in rat isolated aortic ring preparations bathed in a potassium-free medium. (-)-Bay k 8644 (0.01-3 microM) caused extracellular calcium-dependent contractile responses, which were significantly greater in tissues with, than deprived of a functional endothelium. In preparations with an endothelium, the contraction was attenuated by quinacrine (1 microM), indomethacin (10 microM) and diclofenac (0.1 microM), but not changed by nordihydroguaiaretic acid (30 microM) or dazoxiben (10 microM). Thus, in the rat aorta bathed in K(+)-free medium, (-)-Bay k 8644 can cause contractile effects, apparently due to the release of an endothelium-derived contractant factor (EDCF) which is proposed to be a cyclo-oxygenase product.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed1987

Statistically adjusted estimates of geographic mortality profiles.

The spatial variation of site-specific cancer mortality rates at the county or state economic area level can provide a) insights into possible etiologic factors and b) the basis for more detailed epidemiologic studies. One difficulty with such studies, especially for rare cancer types, is that unstable local area rate estimates, resulting from small population sizes, can obscure the underlying spatial pattern of disease risk. This paper presents a methodology for producing more stable rate estimates by statistically weighting the local area rate estimate toward the experience at the national level. The methodology is illustrated by the analysis of the spatial variation of two cancer types, bladder and lung, for U.S. white males over the three decades 1950-79.

Age Factors↗
PubMed2005

Safety, pharmacodynamics, and pharmacokinetics of single doses of BAY 59-7939, an oral, direct factor Xa inhibitor.

BACKGROUND AND OBJECTIVE: There is a clinical need for new oral anticoagulants to prevent and treat thromboembolic diseases. Given its integral role in the coagulation cascade, factor Xa is a particularly promising target for new anticoagulation therapies. The aim of this study was to investigate the safety, pharmacodynamics, and pharmacokinetics of BAY 59--7939, an oral, direct factor Xa inhibitor. METHODS: This single-center, randomized, single-blinded, placebo-controlled, dose-escalation study included 108 healthy white male subjects aged 19 to 45 years. Subjects received single oral doses of either BAY 59--7939 (1.25--80 mg) or placebo; in addition, 1 group received 2 doses of BAY 59--7939 (5--mg tablet and oral solution) or placebo in a crossover design. RESULTS: Oral BAY 59--7939 in single doses up to 80 mg was safe and well tolerated and was not associated with an increased risk of bleeding compared with placebo. Pharmacodynamic effects (inhibition of factor Xa activity, prothrombin time, activated partial thromboplastin time, and Hep Test) and plasma concentration profiles were dose-dependent. Maximum inhibition of factor Xa activity was achieved 1 to 4 hours after administration of BAY 59--7939 and ranged from 20% to 61% for the 5- to 80-mg doses. BAY 59--7939 selectively inhibited factor Xa activity; thrombin (factor IIa) and antithrombin were unaffected. Inhibition of factor Xa activity and prolongation of prothrombin time correlated well with BAY 59--7939 plasma concentrations (r=0.949 and 0.935, respectively). CONCLUSIONS: BAY 59--7939 was well tolerated with predictable pharmacodynamics and pharmacokinetics across a wide range of doses in healthy male subjects. BAY 59--7939 was shown to be an effective and specific factor Xa inhibitor.

Adult↗
PubMed2006

Modeling the relation between socioeconomic status and mortality in a mixture of majority and minority ethnic groups.

Ethnic variation in mortality and whether this variation can be explained by socioeconomic status are of substantive interest to social epidemiologists. The authors consider the analysis of mortality data for a mixture of majority and minority ethnic groups. Such data are likely to be coarsely cross-classified by age and socioeconomic status and yet, even then, in some cells of this cross-classification the observed mortality rate will be an imprecise estimate of the underlying rate. The authors illustrate conventional and Bayesian approaches to analysis with data from the 1996 census used by the New Zealand Census-Mortality Study. A conventional approach is exploratory data analysis first followed by Poisson regression. The authors use spline smoothing within a generalized additive model framework as an exploratory data analysis, following a strategy of adding just enough model structure to gain a sensible picture. A Bayesian approach is modeling first and then a description of posterior estimates using exploratory data analysis techniques. The authors use hierarchical Poisson regression and then illustrate their posterior estimates of the mortality rate using the same spline smoothing as before. The advantage of the hierarchical Bayesian approach is that it assesses uncertainty about a Poisson regression model proposed a priori; the conventional approach assumes that the fitted Poisson regression model is correct. All analyses use software that is available at no cost.

Age Factors↗
PubMed2006

Rivaroxaban (BAY 59-7939)--an oral, direct Factor Xa inhibitor--has no clinically relevant interaction with naproxen.

AIMS: Rivaroxaban (BAY 59-7939) is in advanced clinical development for the prevention and treatment of thromboembolic disorders. Frequent co-medications in the patient populations likely to receive rivaroxaban include NSAIDs. This randomized, two-way crossover study, with a naproxen run-in period, was performed to determine whether naproxen influences the tolerability, pharmacodynamics and pharmacokinetics of rivaroxaban. METHODS: Eleven healthy, young males received naproxen 500 mg on two consecutive days, a single dose of rivaroxaban 15 mg, or both. RESULTS: Treatments were well tolerated: adverse events (eight in total), reported by three subjects, were mild and not drug related. Rivaroxaban inhibited Factor Xa activity by 35% and prolonged prothrombin time [by 1.4 times baseline (tb)], activated partial thromboplastin time (1.3 tb) and the HepTest (1.9 tb). Naproxen had no influence on these measures and the combination of rivaroxaban and naproxen did not affect platelet aggregation. Rivaroxaban and naproxen given together significantly increased bleeding time compared with rivaroxaban alone (P = 0.017). However, this difference was small compared with the effect of naproxen given alone, except in one subject. Least squares-means ratios for the AUC and C(max) of rivaroxaban after administration alone and with naproxen were 1.125 [90% confidence interval (CI) 0.995, 1.271] and 1.095 (90% CI 0.905, 1.325), respectively. CONCLUSIONS: There appeared to be no clinically relevant interaction between rivaroxaban and naproxen in healthy subjects, although some individuals may be more sensitive to the combination. Large-scale Phase III clinical studies will be required to confirm whether there is an increased risk of bleeding during treatment with rivaroxaban and concomitant NSAIDs.

Administration, Oral↗
PubMed1975

[Consequences of the daily rhythm of organ functions and of metabolic processes for screening].

The effects of the influencing factors such as age, sex, exposition to pharmaca, physical activity, alimentary load and endogenic daily rhythm on sensitivity and specifity of the parameters of screening are briefly described. It is reported on the results of examinations of one of these influencing factors and on the endogenic daily rhythm with the help of selected instances.

Adult↗
PubMed2005

Empirical Bayesian analysis of accident severity for motorcyclists in large French urban areas.

The present article deals with individual probabilities of different levels of injury in case of a motorcycle accident. The approach uses an empirical Bayesian method based on the Multinomial-Dirichlet model, see [Leonard, T., 1977. A Bayesian approach to some Multinomial estimation and pretesting problems, J. Am. Stat. Association, 72, 869-874], to conduct an analysis of the probability distributions about the severity of accidents at the level of individuals in large and dense French urban areas during year 2003. We model accident severity using four levels of injury: material damages only, slight injury, severe injury, fatal injury. Our application shows that sociodemographic characteristics of motorcyclists and factors influencing their speed behaviors, the suddenness of their collision and the vigilance of road users play significant roles on the shapes of their probability distributions of accident severity. The computation of posterior distributions of the levels of injury for different groups of motorcyclists enables us to rank them with respect to their risk of injury using second order stochastic dominance orderings. It is found that women motorcyclists between 30 and 50 years old driving powerful motorcycles are the most exposed to risk of injury.

Accidents, Traffic↗
PubMedDate not supplied

Statistical issues in the analysis of disease mapping data.

In this paper we discuss a number of issues that are pertinent to the analysis of disease mapping data. As an illustrative example we consider the mapping of larynx cancer across electoral wards in the North West Thames region of the U.K. Bayesian hierarchical models are now frequently employed to carry out such mapping. In a typical situation, a three-stage hierarchical model is specified in which the data are modelled as a function of area-specific relative risks at stage one; the collection of relative risks across the study region are modelled at stage two; and at stage three prior distributions are assigned to parameters of the stage two distribution. Such models allow area-specific disease relative risks to be 'smoothed' towards global and/or local mean levels across the study region. However, these models contain many structural and functional assumptions at different levels of the hierarchy; we aim to discuss some of these assumptions and illustrate their sensitivity. When relative risks are the endpoint of interest, it is common practice to assume that, for each of the age-sex strata of a particular area, there is a common multiplier (the relative risk) acting upon each of the stratum-specific risks in that area; we will examine this proportionality assumption. We also consider the choices of models and priors at stages two and three of the hierarchy, the effect of outlying areas, and an assessment of the level of smoothing that is being carried out. For inference, we concentrate on the description of the spatial variability in relative risks and on the association between the relative risks of larynx cancer and an area-level measure of socio-economic status.

Age Factors↗
PubMed2005

Assessing intervention effects in a community-based trial to reduce self-harm: a methodological case study.

This paper considers the assessment of the impact of a community-based randomized controlled trial to reduce repeat deliberate self-harm. It considers the drawbacks in simplistic applications of conventional significance testing procedures, as well as possible failures regarding the statistical assumptions underlying such tests. Instead, the paper considers how relevant prior information might be incorporated within a fully Bayesian-model-based assessment procedure. The model includes a latent trait approach to patient morbidity; controlling for morbidity and other patient characteristics enhances the impact of the intervention (measured by a hazard rate ratio). If allowance is made for external information (e.g. ethical approval of the treatment), the weight of evidence shifts towards a positive intervention effect.

Adolescent↗
PubMed1994

Quantitating familial cancer risk: a resource for clinical oncologists.

PURPOSE: Because a family history of cancer constitutes an important risk factor, estimation and communication of cancer risk can facilitate efforts toward early detection and prevention. This review provides a resource for health professionals called to draw upon a multidisciplinary literature to provide quantitative risk estimates to families with cancer. DESIGN: Descriptive population-derived, epidemiologic, genetic, genetic epidemiologic, and molecular studies are critically reviewed in the context of cancer genetic counseling. RESULTS: Data are presented that document the increased lifetime relative risk to relatives of individuals with cancers of the breast, ovary, colon, prostate, or other sites. In general, risk ratios are poorly suited for clinical counseling. Age-specific absolute risks are presented for first-degree relatives of individuals affected by cancers of the breast, ovary, and colon. The derivation of Mendelian and Bayesian risk estimates in the setting of well-defined cancer family syndromes, and the growing role of DNA testing in more accurately assessing these risks, are discussed. Such carrier testing requires careful psychologic and ethical considerations. CONCLUSION: Multidisciplinary cancer genetic counseling is an emerging resource available to physicians who care for families with common adult malignancies.

Age Factors↗
PubMed1984

The predictive factor--a method to simplify Bayes' formula and its application to diagnostic procedures.

According to Bayes' rule the predictive value (PV) of a diagnostic test (= probability of disease if the test is positive) depends on the prevalence of the disease (= a priori probability), the sensitivity (c1) and the specificity (c2) of the test. A new variable has been introduced, the predictive factor (c), which is calculated as follows: c = c1/(c1 +1 -c2). Since the PV only depends on this factor and on the prevalence, the calculation is much easier and a general graphical solution is possible. This simplification renders several additional advantages and facilitates the understanding of the dependence of PV on prevalence.

Bayes Theorem↗
PubMed2005

Epidemic and spatial dynamics of Lyme disease in New york State, 1990-2000.

Lyme disease (LD) occurrence in New York State (NYS) has not only increased over time but also spread throughout the state from the original disease focus in southeastern NYS. Few studies have investigated this epidemic and spatial dynamic in great detail. Using data from the NYS Department of Health Lyme Registry Surveillance System, we summarized epidemic and spatial characteristics of LD in NYS for the 11-yr time period from 1990 through 2000. New epidemiological trends associated with age, sex, and residential influences on LD over time were found. An empirical Bayes approach was used to produce maps of smoothed incidence at different time points to give a foundation for future state and local health funding plans and education programs.

Age Factors↗
PubMed2000

Risk of HIV infection as a function of the duration of intravenous drug use: a non-parametric Bayesian approach.

We analyse the elapsed time between intravenous (IV) drug initiation and HIV infection in a cohort of 972 injecting drug users attending a hospital detoxification unit. We use the time of seroconversion instead of the time of HIV infection because the date of HIV infection is rarely known and the gap between these two times is negligible (around one to three months). Although seroconversion time cannot be determined exactly, it can be inferred at least to within an interval. This seroconversion interval is determined from the dates of HIV antibody tests, if available. The data is consequently interval-censored. We estimate the distribution function of the elapsed time from IV drug initiation to seroconversion as well as the risk of seroconversion by means of a non-parametric Bayesian approach. The analysis is conducted according to the following four calendar periods: before or at 1980; between 1981 and 1985; between 1986 and 1991; after or at 1992 where the IV drug use was initiated. The methodology used is based on an alternating conditional sampling algorithm. The Bayesian approach allows not only the incorporation of prior beliefs about the distribution function, but also the analysis of the risk of seroconversion without assuming restrictive parametric models. Furthermore, the estimator for the distribution function is smooth and thus differences between groups can be easily interpreted.

Adolescent↗
PubMedDate not supplied

[Detection of mental health problems in childhood].

OBJECTIVE: To validate the Report Questionnaire for children (RQC) in order to estimate the prevalence of childhood psychiatric disorders in Mexico. MATERIAL AND METHODS: The RQC was applied by random selection to parents of children in a specialized care service, in a general practice setting and in schools, during an urban household survey within the National Mental Health Survey (NMHS) conducted in 1988. The sample size of adults participating in the NMHS was 2,025. Fifty-two percent (1,068) reported having a child between 3 to 12 years old living in the household. The data collection instrument was applied to the oldest children in that range. The weighted mean was used for analysis and the unbiased prevalence was estimated using the formula proposed by Rogan and Gladen; predictive values were computed using a Bayesian expression. RESULTS: The estimated prevalence of mental health disorders for children aged 3 to 12 years old was between 16.4% and 20.7%. The Positive Predictive Value of the instrument ranged between 46.6% and 76.1%, depending of the cut-off points: one or more positive items in the questionnaire or two or more. The Negative Predictive Value (NPV) ranged between 91.6% and 99.2%. CONCLUSIONS: The estimates are very similar to those reported in different countries and the NPV supports the reliability of the estimates and the potential uses of the instrument for the early detection of childhood psychiatric disorders.

Adult↗