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Biomedical subjects

J Riedel

Publications and source records attributed to J Riedel.

At least 19 recordsLinked to original sources
PubMed2006

Associations of perceived work strain with nicotine dependence in a community sample.

BACKGROUND: Little is known about work strain and smoking, and even less about work strain and nicotine dependence. AIM: To investigate the relations of perceived work strain with nicotine dependence among an adult general population sample. METHOD: Cross sectional survey with a probability sample of residents of a northern German area with 4075 participants, aged 18-64 years (participation rate 70.2%). The current study is based on 2549 participants who were working 15 or more hours per week. Face to face at-home computer aided interviews (World Health Organization Composite International Diagnostic Interview) were carried out. Work strain, defined as high work demand and low work control, was assessed with a questionnaire. Nicotine dependence was diagnosed according to the Diagnostic and Statistical Manual (DSM-IV) of the American Psychiatric Association. In addition, the Fagerström Test for Nicotine Dependence (FTND) was used. RESULTS: Subjects with work strain had an odds ratio of 1.6 (95% CI 1.2 to 2.3) for nicotine dependence compared to those who had no work strain. In a general linear model, higher work strain was associated with a stronger relation between work demand and work control and the FTND. The findings were adjusted for alcohol use disorders, occupational status, age, and sex. CONCLUSION: Perceived work strain is related to nicotine dependence in this general adult population.

Adolescent↗
PubMed2004

Photodissociation dynamics of pyrrole: evidence for mode specific dynamics from conical intersections.

The H and D atom elimination mechanisms in the photodissociation of jet cooled pyrrole and pyrrole-d1 have been studied by photofragment velocity map imaging. The molecules were excited to the 1 1A2 (pi sigma*) state at lambda = 243 nm and to the 1 1B2 (pi pi*) state at lambda = 217 nm. H/D atoms were detected by (2 + 1) resonance enhanced multiphoton ionization (REMPI) at lambda = 243 nm. The analysis of the images and the resulting translational energy distributions from the 1 1A2 state demonstrates the existence of two decay pathways, fast mode-specific cleavage of the NH bond in the excited state (channel A) and internal conversion (IC) to the electronic ground state (S0) followed by unimolecular decomposition of the vibrationally hot S0 molecules (channel B). The angular distributions of the H/D atoms from the direct dissociation in the excited state are strongly anisotropic, whereas the decay of the S0 molecules leads to spatially isotropic distributions. The results at lambda = 217 nm indicate that the 1 1B2 state undergoes an ultrafast radiationless transition to 1 1A2 followed by the abovementioned direct mode-specific NH bond fission on the 1 1A2 potential energy surface (channel A') or conversion to S0 and subsequent unimolecular decomposition (channel B'). The latter pathway may also be initiated by a direct relaxation from 1 1B2 to S0. The anisotropy parameter of beta approximately -1 for the direct NH bond fission at lambda = 217 nm is in accordance with the expectations for a perpendicular electronic excitation and a dissociation lifetime that is short compared to the rotational period of the molecules. The fast decay dynamics of both excited electronic states can be rationalized with reference to the theoretically predicted conical intersections between the pi pi*, pi sigma*, and S0 potential energy surfaces and the antibonding nature of the pi sigma* potential energy surface with respect to the NH bond [A. L. Sobolewski, W. Domcke. C. Dedonder-Lardeux and C. Jouvet, Phys. Chem. Chem. Phys. 2002, 4, 1093].

Photochemistry↗
PubMed2004

[Characteristics of patients with alcohol- or drug problems in medical practices "addiction" in Mecklenburg-Vorpommern].

BACKGROUND: The pilot scheme "Medical practices with emphasis on addiction" examines one approach in the outpatient treatment of patients with addiction. Nine medical practices in Mecklenburg-West Pomerania participate in this project, and the goal is to lower the threshold for the utilisation of help and to provide a long-term relationship between the patient and the physician. GOAL: Results of the first survey of patients and physicians are presented as part of the scientific evaluation of the entire project. METHOD: Data of 876 patients was assessed. There is data about the severity of alcohol dependence (SESA), about negative consequences of drinking and about utilisation of help for n = 627 patients. These were compared with a sample of n = 153 subjects with a diagnosis of alcohol dependence from a population-based survey. Medical doctors provided information on the duration and quality of patient contact, current drug consumption and content of treatment for n = 472 patients. RESULTS: Of all patients, 51 % were treated for more than 3 years in the respective practice. Among the patients, 45 % were current drug users, further help was recommended for 77 %. In comparison with the reference group, patients with a diagnosis of alcohol dependence in those practices were more severely dependent, reported more problems concerning health, work, or finances and utilised addiction-specific help more often. DISCUSSION: The medical practices under examination undertake the task to provide long-term support for patients with addiction diagnoses and encourage patients to utilize more help from further sources. Their patients with alcohol diagnoses differ substantially from persons in the general population with regard to severity of dependence and related problems. This justifies an intensive medical and psychosocial support by specialised practitioners.

Adolescent↗
PubMed2003

[Feasibility and reliability of a transtelephonic 12 leads ECG].

Feasibility and reliability of a 12 lead electrocardiogram (ECG), recorded by the patient himself and transmitted via telephone are mandatory for prehospital diagnosis of myocardial ischemia in patients with coronary heart disease. In this study, a 12-lead ECG recorded by patients and transmitted to the cardiology call center via telephone (Tele-ECG; model CG-7100; Card Guard) was compared with the conventional 12-lead ECG from the same patient recorded at the same time in 128 cases. The Tele-ECGs received by the call center were compared with conventional ECG by two cardiologists and one internist independently and blindly. In relation to the conventional ECG, reproducibility of PQ, QRS and QT-durations [ms] as measured in the Tele-ECG was 85%. Concordance between Tele-ECG and conventional ECG in the detection of negative T-waves was very high (Kappa value (kappa) 0.94, 0.96 and 0.97), respectively, depending on the physician. ST-segment changes were diagnosed correctly in most of the cases in Tele-ECG (kappa=0.98-0.99), as compared with the conventional ECG by all physicians. Concordance between Tele- and conventional ECG concerning the pattern of old myocardial infarction was very high (kappa=0.99) for all infarct localization. The limitations of Tele-ECG were of technical nature. In 14 cases, the peripheral electrodes were displaced; in 12 cases, there were baseline artifacts. These technical errors could be corrected in 126/128 patients (98.4%) by transtelephonic verbal communication. In conclusion, the reliability and feasibility of the 12-lead Tele-ECG-recorder used in this pilot study could be demonstrated. In an ongoing randomized controlled multicenter study, it is being investigated whether the strategy of prehospital diagnosis of acute coronary syndromes by Tele-ECG in combination with verbal communication is able to reduce pre- and in-hospital time delay, to avoid unnecessary hospital admissions and to reduce the economic burden of coronary heart disease.

Aged↗
PubMed2002

[Supracondylar humerus fracture in childhood--an efficacy study. Results of a multicenter study by the Pediatric Traumatology Section of the German Society of Trauma Surgery--I: Epidemiology, effectiveness evaluation and classification].

In this retrospective study of the pediatric trauma group of German trauma society, issued to investigate the state of the art treatment of the supracondylar fracture of the humerus, 13 clinics took part. In this first part of our study we tested the epidemiology and effectivity of therapeutic interventions based on the classification of v. Laer. 886 fractures were included with an average patients age of 5.8 years (+/- 2.9). Causes of trauma was in 45% playing, followed by school/kindergarden and sports injuries. Fractures were initially classified according to v. Laer and showed following displacement: 35.4% Type I, 21.9% Type II, 18.1% Type III and 24.6% Type IV. 10 of the 886 cases (1.1%) were open fractures. Damages to nerves were described in 45 patients (5.1%) and only 7 (0.7%) had primary vessel lesions. 476 patients were treated by reduction of fragments, 72% using a closed technical approach and 28% using an open approach. 6% underwent a second resposition-maneuver, which was mainly observed after crossed Kirschner-wire in type-III-and-IV-fractures. Therapy was changed in 5.1% mostly of the cases were initially closed reduced and then fixed with a collar and cuff sling. 540 patients were seen at follow-up (61%). 81.1% of these patients showed symmetrical axis compared to the uninjured arm. A varus-deformity was noted in 11.7%, a valgus-deformity in 7.2%. Analysis of effectivity showed that the primarily used classification was not sufficient for prediction of the outcome after reposition and retention. Therefore the classification was modified based on 4 groups: Type I undisplaced, Type II displacement in one plane, Type III displacement in two planes and Type IV displacement in three spatial planes. Using this classification we could found that in group II 25% of reduction an 7% of retentions were ineffective. For group III and IV we found that > 20% of the retention proofed to be ineffective.

Adolescent↗
PubMed2002

[Relationship between subjectively perceived working conditions and alcohol consumption: results of the TACOS study].

The purpose of this investigation was to examine the relationship between subjectively perceived working conditions and alcohol consumption based on a stress coping model. The investigation is part of the study 'Transitions in Alcohol Consumption and Smoking' (TACOS), a representative general population survey in a Northern German region. The current evaluation includes 2,471 working individuals, aged 18-64 years. Data with regard to alcohol consumption were collected via the 'Munich Composite International Diagnostic Interview' (M-CIDI). The three scales of the 'Normative and Subjective Assessment of working analysis' (NUSA) Contents of work, Physical work conditions and Intensity of work gathered differentiated information on subjectively perceived working conditions. The ANOVA results show that alcohol consumption does not account for variance in the scales of subjective working conditions. Further correlation and regression analyses do not reveal a relationship between the scales of NUSA and the quantity of drinking.A substantial relationship between subjectively perceived working conditions and moderate alcohol consumption, alcohol abuse or alcohol dependence could not be established. The reported results appear to indicate complex and multifactorial associations between subjectively perceived working conditions and alcohol consumption. Implications for alcohol prevention in worksite environments are discussed.

Adaptation, Psychological↗
PubMed2001

Nonlinear parametric instability in double-well lattices.

A possibility of a nonlinear resonant instability of uniform oscillations in dynamical lattices with harmonic intersite coupling and onsite nonlinearity is predicted. Numerical simulations of a lattice with a double-well onsite anharmonic potential confirm the existence of the nonlinear instability with an anomalous value of the corresponding power index, approximately 1.57, which is intermediate between the values 1 and 2 characterizing the linear and nonlinear (quadratic) instabilities. The anomalous power index may be a result of a competition between the resonant quadratic instability and nonresonant linear instabilities. The observed instability triggers transition of the lattice into a chaotic dynamical state.

Journal Article↗
PubMed2001

The chloroplastic glutamine synthetase (GS-2) of tobacco is phosphorylated and associated with 14-3-3 proteins inside the chloroplast.

The chloroplastic isoform of glutamine synthetase (GS-2, EC 6.3.1.2) from Nicotiana tabacum L. is phosphorylated at the serine residues. At least three of the six GS-2 subunits separated by two-dimensional polyacrylamide gel electrophoresis cross-reacted with an antibody raised against phosphoserine. This provoked the question as to whether 14-3-3 proteins might be present in the chloroplast and bind to chloroplastic GS-2. Although two different 14-3-3 proteins of 32 and 30 kDa were present in total leaf extracts, in the soluble fraction of chloroplasts, only the 32-kDa 14-3-3 protein was immunodetected with an antibody raised against a conserved region of 14-3-3 protein from corn. This demonstrates the presence of a chloroplast-located isoform of 14-3-3 proteins in tobacco. To examine a putative binding of GS-2 to these 14-3-3 proteins in vivo, the native GS-2 holoenzyme was probed with a 14-3-3 antibody. The strong cross-reaction between GS-2 and the 14-3-3 antibody clearly points to a binding of GS-2 and 14-3-3 in tobacco chloroplasts. Only those oligomers of GS-2 that were strongly associated with 14-3-3 proteins were catalytically active.

14-3-3 Proteins↗
PubMed2001

4,4'-Bipyridine dihydrate at 130 K.

The 4,4'-bipyridine molecules in the title compound, C10H8N2.2H2O, are stacked in the direction of the crystallographic b axis. These stacks are connected via O-H...N and O-H...O hydrogen bonds to form sheets which lie parallel to (100). Chains of O-H...O hydrogen-bonded water molecules are located between the bipyridine stacks. Altogether, four crystallographically independent water molecules and two crystallographically independent bipyridine molecules are involved.

Journal Article↗
PubMed1999

Biotransformation and toxicokinetics of musk xylene in humans.

Musk xylene (1-tert-butyl-3,5-dimethyl-2,4,6-trinitrobenzene, MX) is widely used as a fragrance ingredient in detergents and toiletries and is an environmental contaminant. High concentrations of MX have been found in fish, and humans are constantly exposed to MX as a result of its stability in the environment. We investigated the biotransformation and toxicokinetics of MX in humans. A single dose of 0.3 mg/kg body wt of 15N-labeled MX (15N-MX) was given to six volunteers (three male and three female) by the oral route and to another six volunteers (three males and three females) by the dermal route. Urine was collected for 96 h after exposure. Blood samples were taken at intervals for up to 140 days after administration. The metabolite 1-tert-butyl-3,5-dimethyl-15N-4-amino-2,6-dinitrobenzene in urine and 15N-MX in plasma were quantified by gas chromatography/electron-capture mass spectrometry (GC-MS/NCI). Peak plasma concentrations of 15N-MX after oral administration were 36-262 and 1.6-5.5 ng/ml plasma after dermal administration. The toxicokinetics of 15N-MX in plasma can be described by a two-compartment kinetic model with an initial rapid decrease, due to the distribution from the blood into a second compartment (likely fat tissue) and a terminal elimination phase with an average half-life of 70 days for both routes of administration. The amount of 1-tert-butyl-3,5-dimethyl-15N-4-amino-2,6-dinitrobenzene (15N-4-A-MX) in recovered urine represented 0.1-0.5% of the oral applied dose of 15N-MX, respectively, 0.02-0.16% of dermal dose. After a short time of invasion the concentrations of 15N-4-A-MX in urine reached a maximum 18-24 h after administration. The further elimination of the metabolite occurred by first-order kinetics with an average elimination half-life of 11.8 h. After the single oral or dermal dose of 15N-MX, 15N-4-A-MX was not detected in hemoglobin. However, hemoglobin samples contained 1-tert-butyl-3, 5-dimethyl-4-amino-2,6-dinitrobenzene (4-A-MX) (11.4-18.9 fmol/mg Hb), likely derived from chronic environmental exposures.

Administration, Cutaneous↗
PubMed1999

Haemoglobin binding of a musk xylene metabolite in man.

1. Musk xylene (1-tert-butyl-3,5-dimethyl-2,4,6-trinitrobenzene) is used as a fragrance component in toiletries, detergents and skin care products. Musk xylene is widely distributed in the environment and has been identified as a persistent contaminant in fish and in mothers' milk. Experimental data in man indicate a slow elimination of musk xylene and a potential for accumulation. Nitroarenes may be biotransformed to the respective amines. Some aromatic amines are known to be tumorigenic in animals and in man. Quantitation of the binding of those aromatic amines to haemoglobin has been proposed as a biomarker of internal exposure. 2. To determine bioavailability, metabolic reduction and haemoglobin binding of musk xylene in man, we investigated the presence of musk xylene metabolites bound to haemoglobin in blood samples from rat and from 10 human volunteers not knowingly exposed to musk xylene. 3. Haemoglobin from the blood samples was isolated, and bound metabolites were liberated as amines by alkaline hydrolysis. In haemoglobin samples from all individuals, 1-tert-butyl-3,5-dimethyl-4-amino-2,6-dinitrobenzene and, after chemical derivatization, the corresponding N-perfluoropropyl amide were identified by GC/MS using electron-impact and electron-capture mass spectrometry. 4. The amounts of 1-tert-butyl-3,5-dimethyl-4-amino-2,6-dinitrobenzene bound to haemoglobin in the human blood samples ranged from 13 to 46 fmol/mg haemoglobin. 5. These data demonstrate that musk xylene is bioavailable in man. The use of haemoglobin binding as a biomarker for nitromusk exposure in the general population warrants further studies.

Adult↗
PubMed1998

Tonic neurogenic inhibition of interleukin-6 secretion from murine spleen caused by opioidergic transmission.

The peripheral nervous system and the immune system were shown to have neurohumoral interactions. This study extends observations that demonstrated neuronal modulation of spontaneous interleukin-6 (IL-6) secretion in the spleen by norepinephrine (NE) and beta-endorphin. Spontaneous IL-6 secretion in vivo was markedly reduced by removal of macrophages with the clodronate technique. Furthermore, spontaneous IL-6 secretion was significantly inhibited at physiological concentrations of cortisol (10(-7) M). In the presence of 10(-7) M cortisol, addition of norepinephrine (NE; 10(-5) M) and isoproterenol (10(-6) and 10(-5) M) significantly increased spontaneous IL-6 secretion (+20%; P = 0.0280, P = 0.0005, and P = 0.0050, respectively). In contrast, addition of beta-endorphin significantly inhibited spontaneous IL-6 secretion in the presence of 10(-7) M cortisol (-40%; 10(-11) M, P = 0.0410; 10(-10) M, P = 0.0005). To study the effect of endogenously released transmitters on spontaneous IL-6 secretion, spleen slices were electrically stimulated with 1, 5, 10, 50, and 100 Hz. Spontaneous IL-6 secretion was markedly reduced at a frequency of 10 Hz with 10(-7) M cortisol present (P < 0.0001). This indicates that the combination of nerve firing at 5-10 Hz and physiological cortisol conditions inhibits spontaneous IL-6 secretion. Inhibition of spontaneous IL-6 secretion from spleen macrophages is most probably due to a net inhibitory effect of opioidergic transmission under these conditions.

Animals↗
PubMed1997

[Rapid progression of hypertrophic cardiomyopathy into a dilated form--unusual course in a young patient. A case report].

Hypertrophic cardiomyopathy is a disorder which primarily affects the myocardium. It is characterized by a hypertrophic left ventricle that shows normal systolic function but impaired diastolic relaxation. The most important complication of HCM, sudden cardiac death, is mainly responsible for a mortality of approximately 3.5% in childhood. While most patients remain asymptomatic for years, there are some reports about patients progressing from hypertrophic cardiomyopathy to a dilative form within years. We report on a boy who was at the age of twelve when hypertrophic cardiomyopathy was diagnosed first. He remained stable for the first years, but at the age of sixteen his cardiomyopathy progressed to a dilative form with reduced systolic function and severe cardiac failure. The possible pathogenesis is discussed and an overview of similar cases reported earlier is given.

Adolescent↗
PubMed1993

Surface-associated, PrfA-regulated proteins of Listeria monocytogenes synthesized under stress conditions.

The expression of the five clustered genes of Listeria monocytogenes: plcA, hly, mpl, actA and plcB is under the control of the positive regulation factor PrfA. Listeriolysin, encoded by the hly gene, is the only prominent PrfA-controlled gene product observed when L. monocytogenes strain NCTC 7973 is cultured in a rich medium at 37 degrees C to the logarithmic growth phase. Stress conditions such as heat-shock or stationary culture conditions lead to the induction of additional PrfA-dependent proteins (PdPs): ActA (92 kDa), a 38 kDa protein of unknown function and a 34 kDa protein which probably represents PlcA. Under nutrient-stress conditions PdPs are preferentially synthesized and in addition to the already known PdPs at least five new, not yet functionally identified PdPs are detected. All PdPs are either secreted or are localized at the cell surface. Differences in the amount as well as the sizes of the PdPs are observed in different L. monocytogenes strains.

Animals↗
PubMed1993

Histologic, immunohistochemical and morphometric study of the mucosa of the total gastric antrum in patients with carcinoma of the stomach.

Examination of gastrin-immunoreactive G-cells, somatostatin-immunoreactive D-cells, enterochromaffin cells and 5-hydroxytryptamine-immunoreactive (5-HT-immunoreactive) cells of the completely mapped histologic antrum (70 to 100 tissue blocks) was done in 20 normal stomachs of persons between 17 and 94 years of age (from forensic autopsy). Results were compared with those of nine patients between 48 and 76 years of age with total gastrectomy for carcinoma of the proximal part of the stomach. Cell counts and morphometric examinations were performed. Results were summarized for the proximal (I), middle (II) and distal (III) one-third of the antrum and for the major (A) and minor (B) curvature side. In normal stomachs, the G-cell count was 2.52 percent of the total gland cell count in AI; 4.25 percent in AII and 4.77 percent in AIII. In BI, the numbers were 2.5 percent, in BII, 3.73 percent and 4.06 percent in BIII. The D-cell count was 0.47 percent in AI, 0.62 percent in AII and 0.58 percent in AIII. The numbers were 0.44 percent in BI, 0.51 percent in BII and 0.51 percent in BIII. In the antrum of the stomach with carcinoma, the G-cells revealed a non-significant 20 to 70 percent lower cell count, while the D-cell count was reduced insignificantly by as much as 35 percent in all areas. The 5-HT-immunoreactive cell count in normal stomachs is 0.25 percent in AI of the total gland cells, 0.32 percent in AII and 0.39 percent in AIII. In B, it shows numerically no difference to that of A. Contrary to the cell count in normal stomachs, the carcinoma antrum revealed a 200 to 400 percent increase in 5-HT-immunoreactive cell count, highly significant in every area of the antrum. Because 5-HT is known as a growth stimulant, especially for tumors, an increase in 5-HT-immunoreactive cells may be a factor that contributes to the initial histologic changes observed during the early phase of gastric tumor.

Adolescent↗
PubMed1992

Isopropylbenzene (cumene)--a new substrate for the isolation of trichloroethene-degrading bacteria.

Various bacterial isolates from enrichments with isopropylbenzene (cumene), toluene or phenol as carbon and energy sources were tested as to their potential to oxidize trichloroethene (TCE). In contrast to toluene and phenol, all isolates enriched on isopropylbenzene were able to oxidize TCE. Two isolates, strain JR1 and strain BD1, were identified as Pseudomonas spec. and as Rhodococcus erythropolis, respectively. TCE oxidation was accompanied by the liberation of stoichiometric amounts of chloride. Initial TCE oxidation rate increased proportional to the substrate concentration from 25 to 200 microM TCE. Maximal initial TCE-degradation rates found here were 4 to 5 nmol.min-1.mg protein-1. The TCE degradation rate decreased with time. The two isolates showed a temperature optimum for TCE degradation between 10 and 20 degrees C. In addition to TCE, R. erythropolis BD1 degraded only cis- and trans-dichloroethene whereas Pseudomonas spec. JR1 was able to oxidize also 1,1-dichloroethene, vinyl chloride, trichloroethane, and 1,2-dichloroethane.

Benzene Derivatives↗
PubMed1986

Diffuse somatostatin-immunoreactive D-cell hyperplasia in the stomach and duodenum.

This paper presents the first case of extensive, diffuse, somatostatin-immunoreactive D-cell hyperplasia in the human stomach and duodenum. It occurred in a 37-yr-old woman, who showed clinical signs of dwarfism, obesity, dryness of the mouth, and goiter. The density of the distribution of D cells was increased 39-fold in the stomach fundus, 23-fold in the proximal antrum, 25-fold in the distal antrum, and 31-fold in the upper duodenum in comparison with normal values. At the same time, the gastrin-immunoreactive cells were increased 2.3-fold in the antrum. Although the range in size of the D cells was within normal limits in all regions examined, the G cells showed pronounced hypertrophy of up to 127%. A possible relationship between the immuno-histochemical findings and the clinical picture is discussed.

Adult↗