Naturalistic changes in the readiness to quit tobacco smoking in a German general population sample.

Background: This study examines naturalistic changes, i.e., changes that occur without formal interventions, in the motivational readiness to quit tobacco smoking.

Influence of drugs and gender on the arterial pulse wave and natriuretic peptide secretion in untreated patients with essential hypertension.

Recent studies have suggested a differential influence of mean pressure and pulse pressure on myocardial infarction and stroke, and differences among the major drugs in their efficacy at preventing these individual endpoints. We hypothesized that antihypertensive drugs have differing influences upon the pulse wave even when their effects on blood pressure are the same. We studied 30 untreated hypertensive patients, aged 28-55 years, who were rotated through six 6-week periods of daily treatment with amlodipine 5 mg, doxazosin 4 mg, lisinopril 10 mg, bisoprolol 5 mg, bendrofluazide 2.

Propylene glycol monomethyl ether (PGME): inhalation toxicity and carcinogenicity in Fischer 344 rats and B6C3F1 mice.

A series of inhalation studies with propylene glycol monomethyl ether (PGME) vapor were undertaken to characterize its subchronic toxicity in mice and chronic toxicity/oncogenicity in rats and mice. Groups of male and female Fischer 344 rats and B6C3F1 mice were exposed to 0, 300, 1,000, or 3,000 ppm vapor from 1 week to 2 years. Primary treatment-related effects included: initial sedation of animals exposed to 3,000 ppm and its subsequent resolution correlating with induction of hepatic mixed function oxidase activity and S-phase DNA synthesis; elevated mortality in high-exposure male rats and mice (chronic study); elevated deposition of alpha2u-globulin (alpha2U-G) and associated nephropathy and S-phase DNA synthesis in male rat kidneys; accelerated atrophy of the adrenal gland X-zone in female mice (subchronic study only); and increased occurrence and/or severity of eosinophilic foci of altered hepatocytes in male rats.

Potential of feature selection methods in heart rate variability analysis for the classification of different cardiovascular diseases.

In this study heart rate variability (HRV) analysis was applied to characterize patients suffering from coronary heart disease (CHD), dilated cardiomyopathy (DCM) and patients who had survived an acute myocardial infarction (MI). On the basis of several HRV parameters, an optimal discrimination between the different kinds of cardiovascular diseases and between the diseases and healthy controls (HC) was derived by feature selection and linear classification. For each task a small favourable subset of a set of 33 potentially interesting HRV measures was selected with the intention of improving the diagnostic value and facilitating the physiological interpretation of HRV analysis.

Heart rate variability before the onset of ventricular tachycardia: differences between slow and fast arrhythmias.

Background: We tested whether or not heart rate variability (HRV) changes can serve as early signs of ventricular tachycardia (VT) and predict slow and fast VT in patients with an implantable cardioverter defibrillator (ICD).

Methods And Results: We studied the ICD stored 1000 beat-to-beat intervals before the onset of VT (131 episodes) and during a control time without VT (74 series) in 63 chronic heart failure ICD patients. Standard HRV parameters as well as two nonlinear parameters, namely 'Polvar10' from symbolic dynamics and the finite time growth rates 'Fitgra9' were calculated.

Construct validity of the stages of change of exercise adoption for different intensities of physical activity in four samples of differing age groups.

Purpose: To examine whether the stages of change of exercise adoption appropriately address strenuous, moderate, and mild intensities of physical activity.

Design And Setting: Secondary analysis of four data sets investigating transtheoretical model (TTM) constructs for exercise adoption.

Subjects: Four samples of differing age groups (adolescents, n = 400; college students, n = 240; adults, n = 346; seniors, n = 504).

Double-blind, placebo-controlled crossover comparison of five classes of antihypertensive drugs.

Objective: Hypertension guidelines recommend initial treatment with a beta-blocker or diuretic and adding the other drug where blood pressure is not controlled. We hypothesized that systematic rotation through the major classes of antihypertensive drugs would demonstrate substantial differences in the pattern of an individual patient's response, and suggest a more rational approach to choosing best treatment.

Design: Thirty-four young hypertensives (age 28-55, median 47) rotated in a double-blind, Latin-square, crossover fashion through 6 weeks of treatment each with amlodipine, doxazosin, lisinopril, bisoprolol, bendrofluazide and placebo.

Postextrasystolic regulation patterns of blood pressure and heart rate in patients with idiopathic dilated cardiomyopathy.

Assessment of fluctuations in heart rate (HR) following a premature ventricular complex (PVC) is valuable for identifying patients at high risk of sudden cardiac death. We hypothesised that postextrasystolic potentiation is the main determinant of the regulation patterns of blood pressure (BP) and HR following a PVC. Twelve patients with idiopathic dilated cardiomyopathy (IDC) and 13 control subjects with single PVCs (comparable coupling intervals) were investigated.

The association between degree of nicotine dependence and other health behaviours. Findings from a German general population study.

Background: To investigate the association between degree of nicotine dependence and unhealthy nutrition, lack of physical activity, and hazardous alcohol drinking.

Methods: Data with respect to cigarette and alcohol consumption, nutrition, and physical activity was collected in a representative general population sample (N = 4.075).

Baroreflex sensitivity, heart rate, and blood pressure variability in normal pregnancy.

Heart rate variability is a relevant predictor of cardiovascular risk in humans. However, to use heart and blood pressure (BP) variability or baroreflex sensitivity as markers for hypertensive pregnancy disorders, it is first necessary to describe these parameters in normal pregnancy. To accommodate the complexities of autonomic cardiovascular control we added parameter domains of nonlinear dynamics to conventional linear methods of time and frequency domains.

[Health behavior of smokers--results of the TACOS (Transitions in Alcohol Consumption and Smoking) Study].

The German TACOS Project (Transitions in Alcohol Consumption and Smoking) provided an opportunity to examine the patterns of health behaviours (nutrition, physical activity, alcohol consumption) of current smokers, ex-smokers and non-smokers with special regard to different degrees of severity of nicotine dependence. Data were collected in the adult general population of Lübeck and 46 surrounding communities, resulting in a representative sample of 4075 individuals. In this sample, 37.

In vivo and in vitro studies of perchloroethylene metabolism for physiologically based pharmacokinetic modeling in rats, mice, and humans.

In vivo experiments in rats and mice and in vitro experiments in rats, mice, and humans have been used to develop and validate a "2nd generation" physiologically based pharmacokinetic (PBPK) model for perchloroethylene (PERC). The refined PBPK model should be useful in the preparation of carcinogenic risk assessment based on amounts of PERC metabolites formed in the livers of rodents and humans according to procedures developed by EPA. A sensitivity analysis of the PBPK model revealed that the most significant uncertainties in this process (other than the choice of the appropriate dose/response model based on mechanism of action of PERC) were in the techniques used to estimate rates of PERC metabolism in humans.

Intracerebral targets and immunomodulation of murine Listeria monocytogenes meningoencephalitis.

In humans, infection with Listeria monocytogenes (L. monocytogenes) can severely affect the central nervous system (CNS). In the present study we have employed a murine model of CNS listeriosis to characterize the intracerebral distribution of L.

Primary non-Hodgkin's lymphoma of the vagina. Case report and review of the literature.

The genital tract as primary site of malignant non-Hodgkin's lymphoma in women is extremely rare, whereas secondary involvement in advanced disease is found in about 40% of cases. In this report a patient is presented who had a primary vaginal non-Hodgkin's lymphoma of the centroblastic type according to the Kiel classification, with an excellent response to cytotoxic chemotherapy (CHOP) and event-free disease for 3 years. A review of the literature shows that favorable prognosis of localized disease seems to be a common experience.

Mutational analysis of the H-ras oncogene in spontaneous C57BL/6 x C3H/He mouse liver tumors and tumors induced with genotoxic and nongenotoxic hepatocarcinogens.

The frequency and mutational profile of H-ras gene activation were determined in spontaneous liver tumors of male C57BL/6 x C3H/He mice and in tumors induced with the genotoxic hepatocarcinogen benzidine.2 HCl or the nongenotoxic hepatocarcinogens phenobarbital, chloroform, and ciprofibrate. DNA sequence analysis of the H-ras gene from representative tumors revealed that 32 of 50 (64%) spontaneous tumors and 13 of 22 (59%) benzidine.

Metabolism and disposition of ethylene carbonate in male Fischer 344 rats.

Ethylene carbonate (EC) has a toxicity profile which resembles that of ethylene glycol (EG). To determine whether the toxicity of EC could be explained on the basis of its metabolism to EG, male Fischer 344 rats were given 200 mg/kg of uniformly labeled [14C]EC in water by gavage and the disposition of the radiolabel was then followed for 72 hr. EC was rapidly metabolized, with approximately 57 and 27% of the administered dose eliminated in the expired air as 14CO2 and in the urine, respectively; the remainder was found in the carcass.

Toxicokinetics in the evaluation of toxicity data.

Toxicokinetics provides a powerful tool, which is not used sufficiently in the conduct and interpretation of animal toxicity studies. In selecting doses for toxicity studies toxicokinetic data can be used effectively. The tools of toxicokinetics are limited only by the toxicologists' understanding of basic biologic mechanisms.

Physiologically based pharmacokinetic modeling with methylchloroform: implications for interspecies, high dose/low dose, and dose route extrapolations.

A unified physiologically based pharmacokinetic (PB-PK) model was developed and used to describe the disposition of methylchloroform (1,1,1-trichloroethane, MC) in three different species (rats, mice, and humans) after four different routes of exposure (inhalation, intravenous injection, bolus gavage, and drinking water administration). Metabolism of MC followed Michaelis-Menten kinetics in each species. Vmax's were calculated from the allometric equation: Vmax = 0.

Research strategy in industrial toxicology.

While much of industrial toxicology is observational in character, pursuit of specific research is needed to facilitate the overall evaluation of potential toxicity for man. Two such areas are the application of physiologic pharmacokinetic models to inter-species extrapolation of toxic effects and an understanding of the role of cellular oncogenes in the process of spontaneous tumor formation in animals. A physiologic pharmacokinetic model was developed for methylene chloride (MeCl2) which describes the fate of MeCl2 and its metabolic products in numerous species including the mouse, rat, hamster and man.

Activation of a cellular proto-oncogene in spontaneous liver tumor tissue of the B6C3F1 mouse.

The controversy surrounding the interpretation of observed increases in the high spontaneous liver tumor incidence of the B6C3F1 mouse after administration of certain chemical agents necessitates a mechanistic understanding into the nature of tumor development in this particular strain of mouse. Recently, cancer genes (oncogenes) have been detected in the DNA from a variety of human tumors and tumor cell lines. These genes have been implicated to play a role in the transformation of normal cells into cancerous ones.