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Biomedical subjects

Bernhard O Boehm

Publications and source records attributed to Bernhard O Boehm.

At least 19 recordsLinked to original sources

Asymmetrical dimethylarginine independently predicts total and cardiovascular mortality in individuals with angiographic coronary artery disease (the Ludwigshafen Risk and Cardiovascular Health study).

BACKGROUND: Asymmetrical dimethylarginine (ADMA) is increased in conditions associated with increased risk of atherosclerosis. We investigated the use of ADMA to predict total and cardiovascular mortality in patients scheduled for coronary angiography. METHODS: In 2543 persons with and 695 without coronary artery disease (CAD) identified by angiography we measured ADMA and recorded total and cardiovascular mortality during a median follow-up of 5.45 years. RESULTS: ADMA was correlated positively to age, female sex, diabetes mellitus, former and current smoking, and C-reactive protein and inversely to HDL cholesterol and triglycerides. ADMA was not associated with body mass index, hypertension, LDL cholesterol, or the presence or absence of angiographic CAD. Glomerular filtration rate and homocysteine were the strongest predictors of ADMA. At the 2nd, 3rd and 4th quartile of ADMA, hazard ratios for all-cause mortality adjusted for age, sex, and cardiovascular risk factors were 1.12 [95% confidence interval (CI) 0.83-1.52], 1.35 (95% CI 1.01-1.81), and 1.87 (95% CI 1.43-2.44), respectively, compared with the 1st quartile. Hazard ratios for cardiovascular death were 1.13 (95% CI 0.78-1.63), 1.42 (95% CI 1.00-2.02), and 1.81 (95% CI 1.31-2.51). ADMA in the highest quartile remained predictive of mortality after accounting for medication at baseline. The predictive value of ADMA was similar to that in the entire cohort in persons with CAD, stable or unstable, but was not statistically significant in persons without angiographic CAD. CONCLUSIONS: ADMA concentration predicts all-cause and cardiovascular mortality in individuals with CAD independently of established and emerging cardiovascular risk factors.

Analysis of Variance↗

Overweight, physical activity, tobacco and alcohol consumption in a cross-sectional random sample of German adults.

BACKGROUND: There is a current paucity of data on the health behaviour of non-selected populations in Central Europe. Data on health behaviour were collected as part of the EMIL study which investigated the prevalence of infection with Echinococcus multilocularis and other medical conditions in an urban German population. METHODS: Participating in the present study were 2,187 adults (1,138 females [52.0%]; 1,049 males [48.0%], age: 18-65 years) taken from a sample of 4,000 persons randomly chosen from an urban population. Data on health behaviour like physical activity, tobacco and alcohol consumption were obtained by means of a questionnaire, documentation of anthropometric data, abdominal ultrasound and blood specimens for assessment of chemical parameters. RESULTS: The overall rate of participation was 62.8%. Of these, 50.3% of the adults were overweight or obese. The proportion of active tobacco smokers stood at 30.1%. Of those surveyed 38.9% did not participate in any physical activity. Less than 2 hours of leisure time physical activity per week was associated with female sex, higher BMI (Body Mass Index), smoking and no alcohol consumption. Participants consumed on average 12 grams of alcohol per day. Total cholesterol was in 62.0% (>5.2 mmol/l) and triglycerides were elevated in 20.5% (> or = 2.3 mmol/l) of subjects studied. Hepatic steatosis was identified in 27.4% of subjects and showed an association with male sex, higher BMI, higher age, higher total blood cholesterol, lower HDL, higher triglycerides and higher ALT. CONCLUSION: This random sample of German urban adults was characterised by a high prevalence of overweight and obesity. This and the pattern of alcohol consumption, smoking and physical activity can be considered to put this group at high risk for associated morbidity and underscore the urgent need for preventive measures aimed at reducing the significantly increased health risk.

Adult↗

Adiponectin and mortality in patients undergoing coronary angiography.

CONTEXT: The adipokine adiponectin has been suggested to protect against coronary artery disease (CAD). However, studies addressing the association between adiponectin and mortality are sparse. OBJECTIVE: The objective of the study was to elucidate the relationship between adiponectin and mortality. DESIGN, SETTING, AND PARTICIPANTS: Adiponectin was determined in 2473 persons with and 673 persons without angiographic CAD. During a mean follow-up period of 5.45 yr, 427 persons with CAD and 55 persons without CAD died. MAIN OUTCOME MEASURE: Hazard ratios for mortality according to adiponectin levels were measured. RESULTS: Adiponectin was positively related to female gender, age, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, homocysteine, and N-terminal pro-B-type natriuretic peptide. It was inversely related to glomerular filtration rate, body mass index, and triglycerides and was low in diabetes mellitus and CAD. An increase of 1 sd in adiponectin was associated with unadjusted and fully adjusted hazard ratios for death from any cause of 1.31 [95% confidence interval (CI) 1.20-1.42] and 1.22 (95% CI 1.12-1.34), and for death from cardiovascular causes of 1.32 (95% CI 1.19-1.45) and 1.23 (95% CI 1.11-1.37), respectively. In angiographic CAD, stable CAD, and unstable CAD, the predictive value of adiponectin was similar to that in the entire cohort, but it did not attain statistical significance in persons without angiographic CAD. Adiponectin was also positively related to the risk of death from noncardiovascular causes. CONCLUSIONS: Despite the common view about adiponectin as a protective molecule in cardiovascular disease, high adiponectin independently predicts all-cause, cardiovascular, and noncardiovascular mortality in individuals with CAD.

Adiponectin↗

G-protein beta3 subunit (GNB3) gene polymorphisms and cardiovascular disease: the Ludwigshafen Risk and Cardiovascular Health (LURIC) study.

A common 825C>T polymorphism in exon 10 of the gene for the beta-3 subunit of heterotrimeric G-proteins, GNB3, has been associated in some studies with traits of the metabolic syndrome as well as coronary artery disease (CAD), but these associations were refuted by other studies. To investigate the role of GNB3 gene variations in CAD and myocardial infarction (MI), we determined five GNB3 polymorphisms (-1429G>A, IVS5 +41G>A, 657T>A, 814G>A and 825C>T) in the Ludwigshafen Risk and Cardiovascular Health (LURIC) cohort, including 2575 patients with angiographically documented CAD and 731 individuals in whom CAD had been ruled out by angiography. None of the GNB3 polymorphisms was associated with CAD, MI, diabetes, hypertension, blood pressure, body weight or body mass index. We conclude that a major contribution of GNB3 gene variants to CAD or MI risk is unlikely.

Aged↗

DRB1*0401-restricted human T cell clone specific for the major proinsulin73-90 epitope expresses a down-regulatory T helper 2 phenotype.

Recently, we have identified proinsulin (P-Ins)(73-90) as an immunodominant T cell epitope of HLA-DRB1*0401 (DR4) subjects with beta-islet cell autoimmunity and of HLA-DR4/CD4 double-transgenic mice immunized with human P-Ins. We have compared the fine specificities of one human CD4 T cell clone and two mouse T cell hybridoma clones recognizing this epitope, and, although these three clones all recognized the same core region (LALEGSLQK), there were major differences in how they interacted with the peptide (p)/HLA complex, reflecting the fact that human P-Ins is a foreign antigen in the mouse and an autoantigen in the type 1 diabetes patient. The human T cell clone was forkhead transcription factor 3 (Foxp3)-positive, a marker for regulatory T cell lineages, and secreted predominantly IL-5, IL-10, and low levels of IFNgamma in response to P-Ins(73-90). This finding is compatible with the previously detected regulatory cytokine pattern in subjects with beta-cell autoimmunity. However, added N- or C-terminal amino acids drastically changed HLA and tetramer binding capacity as well as T cell reactivity and the cytokine phenotype of the P-Ins(73-90)-specific human CD4 T cell clone, suggesting a potential for this P-Ins epitope as a target for therapeutic intervention in HLA-DR4-positive humans with beta-islet cell autoimmunity or recent-onset type 1 diabetes.

Amino Acid Sequence↗

The angiotensin-I converting enzyme I/D polymorphism is not associated with type 2 diabetes in individuals undergoing coronary angiography. (The Ludwigshafen Risk and Cardiovascular Health Study).

The deletion (D) allele of the angiotensin-I converting enzyme (ACE) is associated with higher ACE activity and has been implicated only recently in the pathogenesis of type 2 diabetes in Caucasian subjects. We have studied the ACE I/D polymorphism in 1054 patients with type 2 diabetes and in 2251 individuals without type 2 diabetes in Caucasians persons undergoing coronary angiography. Further parameters of glucose metabolism (fasting glucose, HbA1c, insulin, C-peptide, pro-insulin, and pancreatic beta-cell function) were analyzed according to the ACE I/D genotype in a subgroup of 2000 individuals in whom an oral glucose challenge was performed. The genotypes ACE II, ID, DD occurred at similar frequencies in patients with type 2 diabetes mellitus (21.0, 50.8, and 28.3%, respectively) compared to non-diabetic individuals (23.3, 49.2, and 27.5%, respectively). There was no association of the ACE D allele with all type 2 diabetes mellitus (OR 1.16, 95%CI, 0.94-1.43), nor with known (OR 1.28, 95% CI, 0.99-1.68) or newly diagnosed diabetes (OR 1.00, 95% CI, 0.75-1.32). These findings were not materially altered when we adjusted for age and gender, cardiovascular risk factors and anti-diabetic or cardiovascular medication. Further the ACE D-allele was not associated with angiographic coronary heart disease or myocardial infarction. The ACE I/D genotype is not associated with type 2 diabetes mellitus, glucose metabolism, coronary heart disease, or myocardial infarction.

Aged↗

Free fatty acids are independently associated with all-cause and cardiovascular mortality in subjects with coronary artery disease.

CONTEXT: Free fatty acids (FFAs) are associated with several cardiovascular risk factors and exert harmful effects on the myocardium. OBJECTIVE: The aim of our study was to elucidate the relationship between FFAs and mortality in subjects who underwent coronary angiography. DESIGN, SETTING, AND PARTICIPANTS: Ludwigshafen Risk and Cardiovascular Health is a prospective cohort study of Caucasians who had undergone coronary angiography at baseline (1997-2000). During a median time of follow-up of 5.38 yr, 513 deaths had occurred among 3315 study participants with measured FFAs. MAIN OUTCOME MEASURE: Hazard ratios for mortality according to FFA levels were measured. RESULTS: At the fourth quartile of FFAs, fully adjusted hazard ratios for death from any cause and cardiovascular causes were 1.58 (P = 0.002) and 1.83 (P = 0.001), respectively. In persons with angiographic coronary artery disease (CAD), stable CAD, and unstable CAD, the predictive value of FFAs was similar to that in the entire cohort, but the association did not attain statistical significance in persons without CAD analyzed separately. FFA levels were not related to the presence of angiographic CAD but were elevated in subjects with unstable CAD, compared with probands with stable CAD. Furthermore, FFAs increased with the severity of heart failure and were positively correlated with N-terminal pro-B-type natriuretic peptide (P < 0.001). CONCLUSIONS: FFA levels independently predict all-cause and cardiovascular mortality in subjects with angiographic CAD. A possible diagnostic use of FFAs warrants further studies, but our results may underline the importance of therapeutic approaches to influence FFA metabolism.

Aged↗

Coexpression of CD25 and OX40 (CD134) receptors delineates autoreactive T-cells in type 1 diabetes.

T-cell-mediated loss of pancreatic beta-cells is the crucial event in the development of type 1 diabetes. The phenotypic characteristics of disease-associated T-cells in type 1 diabetes have not yet been defined. The negative results from two intervention trials (the Diabetes Prevention Trial-Type 1 Diabetes and the European Nicotinamide Diabetes Intervention Trial) illustrate the need for technologies to specifically monitor ongoing autoimmune reactions. We used fluorescence-activated cell sorter analysis to study surface marker expression on T-cell lines specific for two major type 1 diabetes autoantigens, GAD65 and proinsulin. We then applied this knowledge in a cross-sectional approach to delineate the phenotype of circulating memory T-cells. The autoreactive T-cells of patients could be distinguished from those of control subjects by their coexpression of CD25 and CD134. Autoantigen-specific T-cells that recognized multiple GAD65- and preproinsulin-derived peptides and coexpressed CD25(+)CD134(+) were confined to patients (n = 32) and pre-diabetic probands (n = 5). Autoantigen-reactive T-cells in control subjects (n = 21) were CD25(+)CD134(-) and recognized fewer autoantigen-derived peptides. Insulin therapy did not induce CD25(+)CD134(+) T-cells in type 2 diabetic patients. The coexpression of CD25 and the costimulatory molecule CD134 on memory T-cells provides a novel marker for type 1 diabetes-associated T-cell immunity. The CD134 costimulatory molecule may also provide a novel therapeutic target in type 1 diabetes.

Autoimmunity↗

Differential effect of interleukin-2 treatment on primary and secondary immunizations in HIV infected individuals.

OBJECTIVES: As interleukin (IL)-2 therapy increases CD4 cell counts in HIV infected subjects, it emerged as a candidate for the partial restoration of immune competence in this disease. METHODS: We studied the frequencies of antigen-specific T cells using single cell resolution cytokine ELISPOT assays and titers of specific antibodies before and after immunization of HIV infected subjects who were treated with HAART or HAART plus IL-2. RESULTS: Subjects seronegative to hepatitis A were vaccinated with hepatitis A antigen. In the non-IL-2 treated group, hepatitis A-specific T cells producing IL-2 and IL-4 along with specific antibodies were induced, showing that these subjects are immune competent and capable of mounting a primary immune response. Additional IL-2 treatment had no significant effect on this primary T cell response; however, booster immunizations with tetanus toxoid or the gp120 depleted HIV vaccine Remune induced higher frequencies of specific interferon (IFN)-gamma producing T cells in IL-2 treated subjects. No impact of IL-2 treatment on these secondary B cell responses was seen. CONCLUSION: Overall, our study showed that IL-2 therapy had no immune enhancing effect on the induction of a primary response, but increased the frequency of IFN-gamma producing memory cells after booster immunization.

AIDS Vaccines↗

IL-2 absorption affects IFN-gamma and IL-5, but not IL-4 producing memory T cells in double color cytokine ELISPOT assays.

Cytokine assays are gaining increasing importance for human immune monitoring because they reliably detect antigen-specific T cells in primary PBMC, even at low clonal sizes. Double color ELISPOT assays permit the simultaneous visualization of cells producing two different cytokines. Permitting the simultaneous assessment of type 1 and 2 immunity and due to the limited numbers of PBMC available from human study subjects, double color assays should be particularly attractive for clinical trials. Since the performance of double color assays has not yet been validated, we set out to compare them to single color measurements. Testing the recall antigen-induced cytokine response of PBMC, we found that double color assays regularly provided lower numbers of IFN-gamma and IL-5 spots than single color measurements when IL-2 detection was part of the double color assay. We showed that the inhibitory effect resulted from IL-2 absorption and could be overcome by either antibody free preactivation cultures or by inclusion of anti-CD28 antibody. In contrast, the simultaneous detection of IL-2 did not affect the numbers of IL-4 spots. Therefore, unlike IL-2/IL-4 and IFN-gamma/IL-5 assays, IL-2/IFN-gamma, and IL-2/IL-5 assays require compensation for the IL-2 capture to provide accurate numbers for the frequencies of cytokine producing memory T cells.

Absorption↗

Adiponectin serum concentrations in men with coronary artery disease: the LUdwigshafen RIsk and Cardiovascular Health (LURIC) study.

BACKGROUND: Adiponectin, the most abundant adipocytokine of adipose tissue cells, has recently been found to be decreased in coronary artery disease (CAD). Data concerning adiponectin in different stages of CAD are rare, and it was not investigated if adiponectin levels are influenced by the severity of angina pectoris. METHODS: Thus, we measured adiponectin serum levels by means of ELISA in 1626 male probands, including 273 control subjects, 367 subjects with silent CAD, 608 patients with stable, and 378 patients with unstable angina. RESULTS: As compared to controls (8.56; 5.85 to 12.85 microg/ml) and subjects with silent CAD (8.60; 5.99 to 12.64 microg/ml), adiponectin was significantly decreased in patients with stable (7.22; 5.06 to 10.41 microg/ml; p < 0.001 for both) and unstable angina (6.72; 4.08 to 10.08 microg/ml; p < 0.001 for both). By a logistic regression analysis, low adiponectin levels were identified as a significant independent predictor for stable and unstable angina (p < 0.001 for both). No significant differences of adiponectin were observed, neither between the stable and unstable angina group, nor between any classes of angina according to the Canadian Cardiovascular Society (CCS) Angina Score for stable angina. CONCLUSIONS: These results suggest, that decreased adiponectin levels are indicative for symptomatic CAD, but are not further influenced by the progression of this disease.

Adiponectin↗

Insulin analogues.

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Diabetes Mellitus, Type 2↗

Islet-cell antigen-reactive T cells show different expansion rates and Th1/Th2 differentiation in type 1 diabetic patients and healthy controls.

The low frequency of islet-cell antigen-reactive T cells in type 1 diabetes makes their direct measurement difficult. Commonly used in vitro expansion could alter in vivo frequencies and Th1/Th2 differentiation states. Using IFN-gamma/IL-4 double color ELISPOT, we tested longitudinally the reactivity of PBMC from HLA-matched diabetic patients and healthy controls to GAD65, IA-2, and proinsulin peptides ex vivo and after in vitro culture. The peptide-reactive T cells showed IFN-gamma bias in the patients' PBMC in the primary assay. During in vitro culture, both IFN-gamma- and IL-4-producing cells were induced in controls, suggesting that the precursor cells were uncommitted naive T cells in vivo. In contrast, in diabetic patients, the ex vivo IFN-gamma response was conserved during culture, suggesting their Th1 commitment. Using CFSE-dye-dilution, we demonstrate that naive T cells expand in vitro at a faster rate than memory cells, which might account for the differences in expansion rates between diabetic patients and controls.

Adult↗

The metabolic syndrome.

The metabolic syndrome is a multifaceted clinical entity resulting from the interaction of genetic, hormonal, and lifestyle factors. Over the past two decades, the number of people diagnosed with the syndrome has steadily increased and is associated with the global epidemic of obesity and diabetes. The metabolic syndrome is characterized by the clustering of disorders which includes high blood pressure, high (pro)insulin concentrations, excess body weight with central obesity, and an altered lipid profile (dyslipidaemia) that increase the likelihood to develop micro- and macrovascular complications, including coronary heart disease or stroke. Each of these disorders is by itself a risk factor for other diseases including diabetes mellitus. In combination, morbidity and mortality are dramatically increased. Because the defining thresholds for establishing the diagnosis of the metabolic syndrome are controversial, the NCEP: ATP III and the WHO have made specific suggestions. The current definitions of the metabolic syndrome can be used as predictors of vascular complications. Risk assessment and subsequent selection of probands for intervention, such as weight reduction and increased physical activity are recommended for the clinical management of the metabolic syndrome.

Albuminuria↗

Prevalence of the metabolic syndrome in southwest Germany.

The metabolic syndrome is a highly prevalent multifaceted clinical entity. Obesity, which is part of the metabolic syndrome, is the fastest growing health-related problem worldwide. Since currently prevalence data of the metabolic syndrome are lacking from Germany, we have applied ATP III-criteria in two urban and rural cohorts. Our population-based studies provide evidence that the prevalence of the metabolic syndrome increases with age. It was found to be more prevalent in a rural population and in this group it clustered in males. As a consequence of our population-based studies evidence that especially the rural population is at high risk for future macrovascular complications is substantiated. The urgent need for preventive measures aimed at reducing the significantly increased health risk is underscored.

Adolescent↗

Class III alleles at the insulin VNTR polymorphism are associated with regulatory T-cell responses to proinsulin epitopes in HLA-DR4, DQ8 individuals.

A variable number of tandem repeats (VNTR) polymorphism upstream of the insulin promoter is strongly associated with type 1 diabetes. The short class I alleles are predisposing and the long class III alleles are protective. As a possible mechanism for this effect, we previously reported a two- to threefold higher insulin transcription from class III than from class I chromosomes in thymus where insulin is expressed at low levels, presumably for the purpose of self-tolerance. In this article, we confirm this finding with independent methodology and report studies testing the hypothesis that class III alleles are associated with T-cell tolerance to (pro)insulin. Cytokine release in vitro after stimulation with 21 overlapping preproinsulin epitopes was assessed in blood mononuclear cells as well as naive and memory CD4+ T-cell subsets from 33 individuals with the high-risk DRB1*04, DQ8 haplotype (12 type 1 diabetic patients, 11 healthy control subjects, and 10 autoantibody-positive subjects). No significant differences between genotypes (24 I/I subjects versus 10 I/III or III/III subjects) were observed for gamma-interferon, tumor necrosis factor-alpha, or interleukin (IL)-4. By contrast, the I/III + III/III group showed a significant threefold higher IL-10 release in memory T-cells for whole proinsulin and the immunodominant region. Given that IL-10 is a marker of regulatory function, our data are consistent with the hypothesis that higher insulin levels in the thymus promote the formation of regulatory T-cells, a proposed explanation for the protective effect of the class III alleles.

Adolescent↗