Biomedical subjects

Klaus Mann

Publications and source records attributed to Klaus Mann.

At least 37 records · Page 2Linked to original sources

PubMed2006

The CC genotype of the GNAS T393C polymorphism is associated with obesity and insulin resistance in women with polycystic ovary syndrome.

OBJECTIVE: Variants in the Gs protein alpha subunit gene (GNAS1) are known to be involved in the pathogenesis of several endocrine and metabolic disorders. To understand genetic determinants of androgen excess, insulin resistance, and obesity in polycystic ovary syndrome (PCOS), we investigated the effect of the common GNAS1 T393C polymorphism on the phenotype of German PCOS women. DESIGN: Two hundred and seventy-eight PCOS women and 820 Caucasian controls were genotyped for the common T393C polymorphism in GNAS1. To this end, genomic DNA was amplified by PCR with specific oligonucleotides and genotypes were determined using the restriction enzyme FokI. In addition, we evaluated whether the T393C polymorphism had an influence on the response to 6 months metformin treatment in a subgroup of 105 PCOS women. METHODS: Anthropometric variables, metabolic parameters including indices of insulin resistance measured by oral glucose tolerance testing, and endocrine biochemical as well as clinical parameters were measured in all PCOS subjects. RESULTS: GNAS1 genotype distributions were not significantly different between PCOS women and controls. In PCOS women, no significant differences in endocrine clinical and biochemical variables were found between the genotypes. However, the C-allele carrier group had significantly higher mean body weight, body mass index, leptin levels, and higher indices of insulin resistance compared with women with GNAS1 TT-genotype. Metformin treatment significantly improved hyperandrogenism, menstrual cyclicity, body weight, and insulin resistance independent of GNAS1 genotype. The major determinant of weight loss was body weight before treatment. CONCLUSION: The T393C polymorphism is not associated with PCOS in Caucasian women, but may represent a genetic marker for increased susceptibility for obesity in this cohort.

Androgens↗

PubMed2005

Free androgen index is superior to total testosterone for short-term assessment of the gonadal axis after renal transplantation.

OBJECTIVE: Recent studies have assessed gonadal function in association with different immunosuppressive drugs in transplanted patients mainly relying on the measurement of total testosterone. It is the aim of this study to assess the short-term changes of the hypothalamic-pituitary-gonadal axis following renal transplantation using the free androgen index (FAI). PATIENTS AND METHODS: The sequential changes in total testosterone, sex hormone-binding globulin (SHBG), gonadotropin and prolactin concentrations were measured in 22 male patients before and after 1-3 days, and 1, 2 and 3 weeks following renal transplantation. RESULTS: Total testosterone and SHBG concentrations dropped significantly after transplantation (total testosterone: baseline: 15.2 +/- 1.6 nmol/l vs. 1 week: 7.9 +/- 0.8 nmol/l vs. 2 weeks: 9.8 +/- 0.9 nmol/l, SHBG: baseline: 29.9 +/- 3.2 nmol/l vs. 1 week: 19.9 +/- 2.1 nmol/l, 2 weeks: 18.9 +/- 2.4 nmol/l, p < 0.01). FAI decreased significantly after day 1-3 returning to values near baseline thereafter (baseline: 60 +/- 9% vs. day 1-3: 38 +/- 6%, 2 weeks: 61 +/- 7%; p < 0.01). There was a significant positive correlation between FAI and renal function. CONCLUSION: Measurement of the free androgen index is superior to total testosterone for assessment of the pituitary-gonadal axis in the first weeks after renal transplantation.

Adult↗

PubMed2005

Nocturnal hormone profiles in patients with schizophrenia treated with olanzapine.

Nocturnal hormone profiles were measured in patients with schizophrenia with predominantly negative symptoms both under drug-free baseline conditions and after subchronic administration of the atypical antipsychotic olanzapine, with the aim of characterizing its pharmacological properties on the neuroendocrine level. The following hormones were studied in the sleep laboratory under polysomnographic control: adrenocorticotrophic hormone, cortisol, growth hormone (GH), prolactin, testosterone, and melatonin. Blood samples were taken at regular time intervals over the night, and serum concentrations of the hormones were determined. Ten patients completed the study, two of them were excluded from analysis due to incomplete hormone profiles. The dynamics of baseline nocturnal hormone secretion were similar to the patterns known from healthy subjects. After the treatment period of about 4 weeks, hypothalamic-pituitary-adrenal axis activity was reduced with decreased cortisol plasma levels compared to baseline conditions. Olanzapine induced a moderate prolactin elevation. The characteristic GH peak around sleep onset, clearly present under baseline conditions, was markedly reduced after treatment. Testosterone and melatonin secretion were not significantly altered. In conclusion, although interpretation is difficult in some cases due to interference with indirect effects of olanzapine administration and the consequences of the clinical course of the underlying schizophrenic disorder, the neuroendocrine findings are consistent with the receptor-binding profile of olanzapine where, beside the D(2) antagonism, the antiserotonergic properties are most important.

Adrenocorticotropic Hormone↗

PubMed2005

Diagnostic discrimination between graft-related and non-graft-related perioperative myocardial infarction with cardiac troponin I after coronary artery bypass surgery.

AIMS: The rise of markers for myocardial injury indicates early graft-related or non-graft-related perioperative myocardial infarction (PMI) after coronary artery bypass grafting (CABG). A diagnostic discrimination between these two situations may enable adequate therapeutic measures, limiting myocardial damage, and improving outcome. METHODS AND RESULTS: In a prospective study, 94 among 3308 consecutive CABG patients underwent acute reangiography because of evidence of PMI. Of these 94 patients, 56 had graft-related PMI (group 1), 38 patients had non-graft-related PMI (group 2), and 95 patients without evidence of PMI and angiographically patent grafts served as control (group 3). Cardiac troponin I (cTnI), creatine kinase (CK), and its MB fraction were determined. CTnI, but not CK/CK-MB levels were significantly higher in group 1 than in groups 2 and 3 at 12 and 24 h after aortic unclamping (P<0.0001). Receiver operating characteristic and multivariable logistic regression analyses indicated cTnI as the best discriminator between PMI 'in general' and 'inherent' release of cTnI after CABG with a cut-off value of 10.5 ng/mL and between graft-related and non-graft-related PMI with a cut-off value of 35.5 ng/mL. CONCLUSION: Perioperative cTnI elevation after CABG separates among patients with graft-related, non-graft-related, and without PMI, however, not earlier than 12 h after surgery.

Aged↗

PubMed2005

Anterior limbic alpha-like activity: a low resolution electromagnetic tomography study with lorazepam challenge.

OBJECTIVE: To verify findings of an independently regulated anterior limbic alpha band source. METHODS: In a randomised cross-over study, the spontaneous EEG was recorded in nine healthy subjects after i.v. lorazepam or placebo. Intracerebral current densities within classical frequency bands were estimated with low resolution electromagnetic tomography [LORETA] and compared between groups with t-statistical parametric mapping [SPM[t]]. A region-of-interest [ROI] based method was used to compare frontal and occipital alpha band activity changes. RESULTS: Irrespective of treatment group, local maxima of alpha band power were localised both in the occipital lobe, Brodman area [BA] 18, and in the anterior cingulate cortex [ACC], BA 32. Statistical parametric mapping showed reduced parieto-occipital, but unaltered frontal alpha band power after lorazepam. This result was confirmed by ROI-based comparison of BA 18 and BA 32. CONCLUSIONS: There was an anterior limbic maximum of alpha band activity which, unlike occipital alpha, was not suppressed by lorazepam. SIGNIFICANCE: The well-known anterior alpha band components may originate from a narrowly circumscribed source, located in the ACC. Frontal and occipital alpha band activities appear to be independently regulated.

Adult↗

PubMed2005

Sleep investigations in erectile dysfunction.

Regarding the aetiology of erectile dysfunction, beside numerous organic causes in many cases psychological factors play an important role. The pathophysiological mechanisms underlying the so-called psychogenic erectile dysfunction are not yet understood. Based on a neurobiological approach to psychogenic erectile dysfunction, polysomnographic investigations were carried out with the aim of identifying possible alterations of the sleep EEG. 24 male patients with psychogenic erectile dysfunction without detectable organic factors or other mental disorders were studied in the sleep laboratory, as well as an age-matched control group without sexual dysfunctions. Beside a reduction of sleep efficacy, the most prominent finding was a shortening of REM latency in the patients compared to the controls. Moreover, spectral analysis revealed a reduced theta power for all sleep stages and a reduced delta power for stage II and slow wave sleep in the patients. The findings support the point of view that psychogenic erectile dysfunction is an organic disorder of the brain. The sleep EEG abnormalities may reflect dysregulations in limbic structures which are suggested to be involved in the pathophysiology of sexual dysfunctions. As these alterations had also been reported for other mental disorders, particularly depression, they appear to be non-specific biological abnormalities for different psychiatric syndromes, including psychogenic erectile dysfunction.

Adult↗

PubMed2005

Sensitive thyrotropin and thyrotropin-receptor antibody determinations one month after discontinuation of antithyroid drug treatment as predictors of relapse in Graves' disease.

OBJECTIVE: After primary successful antithyroid drug treatment (ATDT), Graves' disease has a relapse rate of 30% to 50%. Previous studies have evaluated age, gender, goiter volume, smoking habits, and the presence of thyrotropin-receptor antibodies (TRAb) as predictive markers to facilitate an individualized patient management. Despite higher sensitivity and specificity of the new second generation human TSH-receptor assay, the predictive value of TRAb for relapse of hyperthyroidism is still controversial. In a recent prospective multicenter study we have previously shown that suppressed or low TSH values predict both early (persistence) and late relapse of Graves' disease. We now present a more detailed analysis of the predictive value of TSH and TRAb for recurrent hyperthyroidism. METHODS: Four weeks after withdrawal of ATDT, 96 patients were available for thyroid function tests, including a sensitive third-generation TSH assay and a second-generation recombinant TSH receptor assay. Relapse of Graves' disease was evaluated for a total follow-up of 2 years. RESULTS: Within 2 years, 47 of 96 patients (49%) developed relapse of hyperthyroidism. Nine patients relapsed within the first 4 weeks after withdrawal of ATDT and were thus considered to have persistent Graves' disease. Ten of 15 other patients with TSH levels below 0.3 mU/L without overt hyperthyroidism relapsed within 2 years. Twenty-five of 65 patients with normal TSH (0.3-3.0 mU/L) and 3 of 4 patients with TSH values above 3 mU/L also had recurrent hyperthyroidism. After ATDT cessation, TSH had a positive predictive value of 70% and a negative predictive value of 62% (specificity 85%) for relapse of Graves 'disease. Mean TRAb levels in the group of patients with relapse were significantly higher (11.1 IU/L +/- 0.17) than TRAb values in the remission group (4.5 IU/L +/- 0.6), p < 0.001. Using a cutoff value of 1.5 IU/L, TRAb had low positive and negative predictive values of 49% and 54%, respectively (specificity, 14%), but with a cutoff level of 10 IU/L, predictive values improved to 83% and 62%, respectively (specificity, 92%). Combination of TSH and TRAb determinations did not further improve prediction of relapse. Other factors such as gender, age, goiter volume, smoking habits, presence of thyroid-associated ophthalmopathy, and urinary iodine excretion did not show a significant influence on relapse rate. CONCLUSION: Low TSH values 4 weeks after ATDT withdrawal predict relapse of Graves' disease, both early (persistence) and, to a lesser extend, within 2 years of follow-up. Also, TRAb above 10 IU/L found in a small subset of patients, correlated with a higher relapse rate.

Adult↗

PubMed2005

The peroxisome proliferator activated receptor gamma Pro12Ala polymorphism is associated with a lower hirsutism score and increased insulin sensitivity in women with polycystic ovary syndrome.

BACKGROUND: Polycystic ovary syndrome (PCOS) is characterized by hyperandrogenism and chronic anovulation. The genetic background of the insulin resistance frequently associated with PCOS is unclear. OBJECTIVES: To examine the influe nce of the Pro12Ala polymorphism of the peroxisome proliferator activated receptor gamma (PPARgamma), which is thought to play a role in the regulation of insulin sensitivity, on endocrine and metabolic parameters in PCOS patients. METHODS: PPARgamma alleles were analysed in 102 PCOS patients (age 27 +/- 5.3 years) and 104 age matched control women. PCOS was defined by the NIH-criteria as the presence of chronic oligo- or anovulation and hyperandrogenism. Family history and clinical parameters were evaluated by personal interview and physical examination, parameters of insulin resistance [homeostasis model assessment (HOMA) and Matsuda-index] were evaluated with a glucose tolerance test. RESULTS: Seventy-nine (77.5%) PCOS patients were carriers of the wild-type PPARgamma allele (Pro/Pro), while 23 (22.5%) had at least one Ala allele (X/Ala), with an equal distribution in controls. X/Ala PCOS women were more insulin-sensitive, evidenced by lower fasting insulin, HOMA index and insulin secretion. Differences in insulin resistance did not depend on body mass index. The genotype had no influence on lipid status, leptin, adiponectin, ghrelin, or family history of type 2 diabetes. A significantly lower proportion of Pro/Ala patients had hirsutism and they had on average lower hirsutism scores than Pro/Pro patients. No relationship was found between the Pro/Ala polymorphism and other signs of hyperandrogenism. CONCLUSION: The Pro12Ala polymorphism of the PPARgamma gene is associated with increased insulin sensitivity and lower hirsutism scores in PCOS women.

Adult↗

PubMed2005

Rosiglitazone is a safe and effective treatment option of new-onset diabetes mellitus after renal transplantation.

The purpose of this study was to assess the safety and efficacy of the insulin sensitizer rosiglitazone in patients with new-onset diabetes mellitus (NODM) after renal transplantation. Twenty-two patients with NODM after renal transplantation were selected to receive rosiglitazone therapy. All patients received prednisone, 15 patients were treated with tacrolimus and seven patients received cyclosporine A. For 16 of the 22 patients treatment with rosiglitazone therapy was successful and mean fasting blood glucose decreased from 182 +/- 17 to 127 +/- 7 mg/dl. Six patients were not treated successfully with rosiglitazone alone, one patient needed a second oral antidiabetic agent and four patients insulin therapy. In one patient rosiglitazone was stopped because of edema after 5 days. There were no changes either in serum creatinine concentrations, or cyclosporine and tacrolimus blood levels respectively. Treatment with rosiglitazone appears to be safe and effective in patients with NODM after renal transplantation.

Diabetes Mellitus↗

PubMed2005

Prognostic value of preoperative cardiac troponin I in patients with non-ST-segment elevation acute coronary syndromes undergoing coronary artery bypass surgery.

STUDY OBJECTIVES: Elevated levels of cardiac troponin I (cTnI) have been associated with adverse short-term and long-term outcomes in acute coronary syndrome (ACS) patients and in patients who underwent coronary artery bypass grafting (CABG); however, the prognostic implications of preoperative cTnI determination have not been investigated so far. DESIGN AND SETTING: Retrospective study in a department of cardiothoracic surgery of a university hospital. PATIENTS AND METHODS: A possible correlation between preoperative cTnI levels and major adverse cardiac events (MACE) and in-hospital mortality in CABG patients with non-ST-segment elevation ACS (NSTE-ACS) was investigated. cTnI was determined in 1,978 of 3,124 consecutive CABG patients. Among these, 1,592 patients had preoperative cTnI levels < 0.1 ng/mL and therefore served as control subjects (group 1), 265 patients had NSTE-ACS with cTnI levels from 0.11 to 1.5 ng/mL (group 2), and 121 patients had NSTE-ACS with cTnI levels > 1.5 ng/mL (group 3). cTnI levels, clinical data, MACE, and in-hospital mortality were recorded prospectively. Logistic regression and receiver operating characteristic analyses were applied to determine prognostic cutoff values of cTnI. RESULTS: Perioperative myocardial infarction was found in 5.8% of the patients in group 1, 8.3% of the patients in group 2 (odds ratio [OR], 1.5; 95% confidence interval [CI], 0.9 to 2.5), and 18.2% patients in group 3 (OR, 3.6; 95% CI, 2.1 to 6.2; p < 0.0001, Cochran-Armitage trend test). Low cardiac output syndrome occurred in 1.5% of patients in group 1, 4.2% of patients in group 2 (OR, 2.8; 95% CI, 1.3 to 6.1), and 10.9% patients in group 3 (OR, 6.5; 95% CI, 2.9 to 14.4; p < 0.0001). In-hospital mortality was 1.5% in group 1, 3.0% in group 2 (OR, 2.0; 95% CI, 0.8 to 4.8), but 6.6% in group 3 (OR, 4.6; 95% CI, 1.9 to 11.1; p < 0.0001). Univariate and multivariate logistic regression analyses identified cTnI as the strongest preoperative predictor for MACE and in-hospital mortality, respectively. CONCLUSIONS: Preoperative cTnI measurement before CABG appears as a powerful and independent determinant of short-term surgical risk in patients with NSTE-ACS.

Aged↗

PubMed2005

Clinical and psychological correlates of quality-of-life in polycystic ovary syndrome.

OBJECTIVE: Polycystic ovary syndrome (PCOS) has been shown to cause a reduction in quality of life. This study examines the extent of different PCOS symptoms on quality-of-life, psychosocial well-being and sexual satisfaction. METHODS: Complete metabolic, hormonal, clinical and psychosocial data were obtained from a total of 120 women with PCOS. Patients were compared with 50 healthy women to establish reductions in quality-of-life and emotional well-being. In addition, the correlation between psychosocial variables and the major clinical PCOS features obesity (body mass index (BMI)), excessive body hair (hirsutism score), acne, hyperandrogenism (serum testosterone levels), disturbed insulin regulation (area under the insulin response curve and homeostasis model assessment of insulin resistance), menstrual cycle disturbances and infertility were analyzed. RESULTS: PCOS patients showed significant reductions in quality-of-life, increased psychological disturbances, and decreased sexual satisfaction when compared with healthy controls. BMI and hirsutism scores, but not the presence of acne, were associated with physical aspects of quality-of-life and sexual satisfaction. No clear effect of androgens or insulin resistance on psychosocial variables was detected. Similarly, the type of menstrual cycle disturbances or infertility had no impact on psychological well-being. CONCLUSION: In PCOS, changes in appearance, particularly obesity and hirsutism, reduce physical dimensions of quality-of-life and decrease sexual satisfaction. The role of biochemical, endocrine and metabolic parameters as well as menstrual irregularities and infertility appeared to be less important. Clinicians should pay attention to the psychosocial dimensions of PCOS on an individual basis, regardless of symptom severity or treatment response.

Acne Vulgaris↗

PubMed2004

Partial versus total adrenalectomy by the posterior retroperitoneoscopic approach: early and long-term results of 325 consecutive procedures in primary adrenal neoplasias.

The retroperitoneoscopic approach is a standardized operative procedure for primary adrenal gland tumors. It allows direct access with a detailed view of the adrenal gland. Thereby, a clear differentiation between normal and neoplastic adrenal tissue is often possible, which permits a planned partial resection of the gland in selected cases. Between July 1994 and November 2003 325 posterior retroperitoneoscopic adrenalectomies were performed for primary benign adrenal gland tumors (106 Conn's adenomas, 83 pheochromocytomas, 76 Cushing's adenomas, 60 nonfunctioning tumors; size: 2.8 +/- 1.5 cm; site: 160 right, 165 left) in 318 patients (122 M, 196 F, age: 49.0 +/- 14.3 years). In 96 patients 100 tumors were removed by partial adrenalectomy (30 Conn's adenomas, 33 pheochromocytomas, 20 Cushing's adenomas, 17 nonfunctioning tumors; site: 61 right, 59 left) maintaining tumor-free parts of the adrenal gland. Of this group, 15 patients suffered from bilateral adrenal neoplastic diseases. During the same period, 225 total adrenalectomies (76 Conn's adenomas, 50 pheochromocytomas, 56 Cushing's adenomas, 34 nonfunctioning tumors; site: 109 right, 116 left) were performed in 224 patients. There was no mortality. Major complications were seen in 1.8%, minor complications in 14.5%. Three conversions were necessary to an open or a laparoscopic approach (2 patients and 1 patient, respectively). There are no differences between the two groups (total versus partial adrenalectomy) with regard to tumor size (2.8 +/- 1.6 cm versus 2.8 +/- 1.5 cm), operating time (80 +/- 44 minutes versus 79 +/- 42 minutes), and blood loss (33 +/- 71 ml versus 29 +/- 31 ml). In all patients with partial adrenalectomy, biochemical healing was proven. Fourteen of 15 patients with bilateral diseases had preservation of adrenocortical function. After a mean follow up of 51 months (range: 7-120 months) local recurrence or relapse of the initial diseases was noticed in 6 patients after total adrenalectomy: in 4 patients with Conn's syndrome and bilateral hyperplasia, and in 2 patients with malignant pheochromocytoma and adrenocortical carcinoma, respectively. Our data demonstrate that partial adrenalectomy is a safe procedure not only perioperatively but also in the long-term follow-up.

Adrenal Cortex Neoplasms↗

PubMed2004

T-cell function after interleukin-2 therapy in HIV-infected patients is correlated with serum cortisol concentrations.

OBJECTIVES: To examine the effects of interleukin (IL)-2 therapy on in-vitro lymphocyte responsiveness in HIV-infected patients and to correlate these data with serum cortisol concentrations. DESIGN: German prospective study. METHODS: In adult patients (n = 32) treated with 9 x 10(6) IU/day interleukin-2, lymphocyte transformation tests (LTT), serum cortisol concentrations and CD4 T-cell counts were assessed before, during and after IL-2 therapy. RESULTS: A significant decrease in responses towards mitogens and recall antigens (P < 0.05) was observed on day 7 after starting a 4- to 5-day IL-2 therapy as compared to baseline. Serum cortisol levels increased (P < 0.0001) reaching a maximum on day 4, and were still elevated on day 7 (P < 0.005). CD4 T-cell counts significantly decreased with a minimum on day 2 before increasing 2.4-fold above baseline on day 7 (P < 0.005 each). A positive correlation (P < 0.05 each) was observed for changes in cortisol levels and in LTT mitogen and antigen reactions (both day 7 - 0), changes in cortisol levels (day 3 - 0) and CD4 cell counts on day 2, and corticotrophin releasing hormone test results and LTT antigen reactions on day 7. LTT responses, cortisol levels and CD4 T-cell counts returned to baseline on day 30. CONCLUSION: Serum cortisol concentrations are predictive of functional and numerical changes of T cells induced by IL-2 therapy.

Adult↗

PubMed2004

Value of plasma fibrin D-dimers for detection of acute aortic dissection.

OBJECTIVES: The purpose of this research was to assess the value of systemic inflammatory biomarkers in the detection of acute aortic dissection (AD). BACKGROUND: Rapid diagnosis and initiation of treatment is pivotal for patients with acute AD. So far, there is no laboratory test to aid the diagnosis. METHODS: Plasma fibrin D-dimers, white blood cell (WBC) count, C-reactive protein (CRP), and fibrinogen were determined in 64 chest-pain (CP) patients (acute AD, n = 16; pulmonary embolism [PE], n = 16; acute myocardial infarction [AMI], n = 16; non-cardiac CP, n = 16); 32 asymptomatic patients with chronic AD served as a control group. RESULTS: All acute AD patients showed highly elevated D-dimer values that were similar to PE patients (2,238 +/- 1,765 microg/l vs. 1,531 +/- 837 microg/l, p = 0.15) but significantly higher than in chronic AD, AMI, or CP patients (p < 0.001). The WBC count was significantly increased in patients with acute AD compared with the other groups (p < 0.001); in addition, CRP values differed only non-significantly from PE patients(p = 0.71). There were no differences in the fibrinogen levels between the groups. CONCLUSIONS: D-dimers are highly elevated in both acute PE and acute AD. Patients with acute AD show significant systemic inflammatory reactions. Measurement of D-dimers may be a valuable addition to the current diagnostic work-up of patients with suspected AD.

Acute Disease↗

PubMed2004

[Cardiovascular effects of oral hypoglycemie drugs].

In the recent years there has been increasing interest in the effects of oral hypoglycemic drugs on the cardiovascular system. This has arisen because of recognitions that thiazolidine-diones, peroxisome proliferators-activated receptor gamma (PPAR-gamma), may have antiatherogenic actions and that sulphonylureas are capable of closing the ATP-dependent potassium channel. PPAR-gamma agonists exert antiatherogenic action by inhibition the production of monocyte inflammatory cytokines, inhibition of expression of adhesion molecules in endothelial cells, inhibition of the proliferation of vascular smooth muscle cells and have antioxidative effects. The United Kingdom Prospective Diabetes Study (UKPDS), published in 1998, found that the use of sulphonylureas had no increase in cardiovascular mortality and that metformin therapy in obese individuals with type 2 diabetes mellitus was associated with reduced cardiovascular death. Recently, the STOP-NIDDM trial has been shown that patients with impaired glucose tolerance treated with the alpha-glucosidase inhibitor acarbose had a significant reduction in the risk of cardiovascular disease. Currently, the results of the UKPDS trial are the only available clinical data on which to base the choice of treatment for type 2 diabetic patients. When a glucose-lowering oral drug is considered necessary and is not contraindicated, the firstline choice is a sulphonylurea or a glinide (repaglinide or nateglinide) for diabetics who are not overweight and metformin for those who are.

Administration, Oral↗

PubMed2004

The thalamus as the generator and modulator of EEG alpha rhythm: a combined PET/EEG study with lorazepam challenge in humans.

BACKGROUND: Purpose of this study was to investigate the functional relationship between electroencephalographic (EEG) alpha power and cerebral glucose metabolism before and after pharmacological alpha suppression by lorazepam. METHODS: Ten healthy male volunteers were examined undergoing two F18-fluorodeoxyglucose (18-FDG) positron emission tomography (PET) scans with simultaneous EEG recording: 1x placebo, 1x lorazepam. EEG power spectra were computed by means of Fourier analysis. The PET data were analyzed using SPM99, and the correlations between metabolism and alpha power were calculated for both conditions. RESULTS: The comparison lorazepam versus placebo revealed reduced glucose metabolism of the bilateral thalamus and adjacent subthalamic areas, the occipital cortex and temporo-insular areas (P < 0.001). EEG alpha power was reduced in all derivations (P < 0.001). Under placebo, there was a positive correlation between alpha power and metabolism of the bilateral thalamus and the occipital and adjacent parietal cortex (P < 0.001). Under lorazepam, the thalamic and parietal correlations were maintained, whereas the occipital correlation was no longer detectable (P < 0.001). The correlation analysis of the difference lorazepam-placebo showed the alpha power exclusively correlated with the thalamic activity (P < 0.0001). CONCLUSIONS: These results support the hypothesis of a close functional relationship between thalamic activity and alpha rhythm in humans mediated by corticothalamic loops which are independent of sensory afferences. The study paradigm could be a promising approach for the investigation of cortico-thalamo-cortical feedback loops in neuropsychiatric diseases.

Adult↗

PubMed2004

Sleep under exposure to high-frequency electromagnetic fields.

The controversy about potential health hazards associated with the exposure to electromagnetic fields (EMF) has been recently stimulated by the increasing use of mobile telecommunication devices. Attention has focused here on non-thermal effects of low-level high-frequency radiation, which does not lead to a heating of tissue. Scientific literature on the effects of high-frequency EMFs on sleep is reviewed. The epidemiological studies provide no evidence that sleep disturbances are a relevant complaint under exposure to such fields. Recent sleep laboratory studies have revealed a number of slight effects. Despite their heterogeneity, there seems to be some consistency regarding a slight sleep-promoting effect and an increase of the alpha power of the sleep EEG induced by high-frequency EMFs. However, for both the epidemiological and sleep laboratory studies, the database concerning sleep is up to now very limited. At the present level of knowledge, no final conclusions can be drawn from the available data concerning potential health hazards. Although there seem to be some biological effects, these do not provide evidence for any adverse health consequences. However, further research is needed for a better understanding of the interaction between EMFs and the sleep process.

Cell Membrane↗

PubMed2004

Acute alcohol effects on neuronal and attentional processing: striatal reward system and inhibitory sensory interactions under acute ethanol challenge.

The acute influence of ethanol on cerebral activity induces complex psycho-physiological effects that are considerably more pronounced during acute ethanol influx than during maximal blood alcohol concentration (elimination phase). Despite the psychiatric and forensic relevance of these different ethanol effects, the underlying neuronal mechanisms are still unclear. In total, 20 male healthy volunteers were investigated each with three different experimental conditions in a randomized order using an intravenous ethanol challenge (40 g bolus infusion): during influx phase, elimination phase, and under placebo condition. During and after the ethanol (or placebo) infusion, neuropsychological testing of divided attention for visual and auditory stimuli was performed with subsequent 18-FDG PET acquisition. The PET data were analysed using SPM99. Ethanol influx and elimination phase showed focal activations in the bilateral striatum and frontal cortex and deactivations in the occipital cortex. The comparison of influx phase vs elimination phase revealed activations in the anterior cingulate and right prefrontal cortex, relevant deactivations were found in the left superior temporal cortex including Wernicke's area. Neuropsychological testing showed an attentional impairment under ethanol influx compared to ethanol elimination and placebo with an inverse correlation of the attentional performance for auditory stimuli to occipital activity and for visual stimuli to the left temporal (including auditory) cortex. Acute ethanol administration in healthy volunteers stimulates those striatal regions that are considered to have a particular relevance for alcohol craving ('reward system'). Modality specific reciprocal inhibition of sensory cortex activity seems to be relevant for attentional performance during acute alcohol impact.

Adult↗