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Biomedical subjects

Werner A Scherbaum

Publications and source records attributed to Werner A Scherbaum.

At least 19 recordsLinked to original sources
PubMed2006

Comparison between Long-Menu and Open-Ended Questions in computerized medical assessments. A randomized controlled trial.

BACKGROUND: Long-menu questions (LMQs) are viewed as an alternative method for answering open-ended questions (OEQs) in computerized assessment. So far this question type and its influence on examination scores have not been studied sufficiently. However, the increasing use of computerized assessments will also lead to an increasing use of this question type. Using a summative online key feature (KF) examination we evaluated whether LMQs can be compared with OEQs in regard to the level of difficulty, performance and response times. We also evaluated the content for its suitability for LMQs. METHODS: We randomized 146 fourth year medical students into two groups. For the purpose of this study we created 7 peer-reviewed KF-cases with a total of 25 questions. All questions had the same content in both groups, but nine questions had a different answer type. Group A answered 9 questions with an LM type, group B with an OE type. In addition to the LM answer, group A could give an OE answer if the appropriate answer was not included in the list. RESULTS: The average number of correct answers for LMQs and OEQs showed no significant difference (p = 0.93). Among all 630 LM answers only one correct term (0.32%) was not included in the list of answers. The response time for LMQs did not significantly differ from that of OEQs (p = 0.65). CONCLUSION: LMQs and OEQs do not differ significantly. Compared to standard multiple-choice questions (MCQs), the response time for LMQs and OEQs is longer. This is probably due to the fact that they require active problem solving skills and more practice. LMQs correspond more suitable to Short answer questions (SAQ) then to OEQ and should only be used when the answers can be clearly phrased, using only a few, precise synonyms.LMQs can decrease cueing effects and significantly simplify the scoring in computerized assessment.

Adult↗
PubMed2006

Corticotropin-releasing hormone receptor expression on normal and tumorous human adrenocortical cells.

Corticotropin-releasing hormone (CRH) is not only the principal regulator of the central hypothalamic-pituitary-adrenal (HPA) axis but also exerts direct actions on peripheral tissues. We analyzed the expression of CRH receptors in microdissected preparations of normal human adrenal glands and in adrenocortical and adrenomedullary tumors, employing immunohistochemistry, quantitative RT-PCR of microdissected adrenal tissues, and in situ hybridization. The effect of CRH on adrenal steroidogenesis was tested in adrenal cells. Immunoreactive CRH1R was found primarily within the zona reticularis. In addition, we found a higher expression of CRH type-1 and 2 receptors mRNAs in preparations of adrenal cortices as compared to pheochromocytomas, a 6-fold increase in preparations of clinically unapparent adrenocortical adenomas, and a 10- to 60-fold increase in cortisol-producing adrenal adenomas. Stimulation of the adrenal tumor cell line NCI-H295R with CRH elicited a 1.4-fold increase in DHEA secretion. This result could be reproduced in a culture of primary human adrenocortical cells. We conclude that adrenocortical cells exhibit a higher expression of functional CRH receptors than chromaffin cells and that CRH acts on adrenal DHEA production. The data support the assertion of a direct action of CRH on human adrenocortical cells in addition to an intra-adrenal CRH receptor/adrenocorticotropin system. Enhanced CRH1R expression may be involved in adrenocortical tumorigenesis.

Adrenal Cortex↗
PubMed2006

Hirsutism.

Explore the source record for details and available documents.

Androgens↗
PubMed2006

Dendritic cells as potential adjuvant for immunotherapy in adrenocortical carcinoma.

OBJECTIVE: Adrenocortical carcinoma (ACC) is a rare malignancy associated with a dismal prognosis. Dendritic cells (DCs) are professional antigen-presenting cells leading to an antitumour immune response. The aim of this study was to elaborate two methods of antigen delivery to DCs and to evaluate an immunotherapy protocol in ACC patients. DESIGN/PATIENTS: Autologous DCs were pulsed with autologous tumour lysate (TL). Fusion of DCs with tumour cells was based on a polyethylene glycol method. Two patients with metastasized hypersecretory ACC were vaccinated twice. MEASUREMENTS: In vitro data were quantified by measurement of PBMC (peripheral blood mononuclear cell) responses and cytokine secretion and by flow cytometry analyses. Clinical response was monitored by CT scan of tumour mass and measurement of angiogenic factors. RESULTS: The maximum loading of TL was obtained at 24 h as 48.2% (+/- 26.8%) of DCs were TL-positive. The DC/tumour cell fusion efficacy was approximately 45% as shown by double positive staining for ACTH receptor and DC-specific CD83. In vivo DC vaccination resulted in positive delayed-type hypersensitivity skin reactions reflecting specific memory T-lymphocyte reaction. In vitro analyses revealed specific T-cell proliferation in patient 1 (stimulation index: 5.7 compared to pretreatment) and induction of cytotoxic granzyme B secreting T cells in patient 2 (0.41% CD8 + cells vs. 0.06% pretreatment) as indicators of specific cytotoxic T cells. Although angiogenic serum markers could be stabilized, no impact on tumour growth could be observed. CONCLUSION: Our data demonstrate that autologous dendritic cells induce antigen-specific Th1 immunity in adrenocortical carcinoma. The clinical outcome, however, was not improved in the patients studied here.

Adjuvants, Immunologic↗
PubMed2006

A case of catecholamine and glucocorticoid excess syndrome due to a corticotropin-secreting paraganglioma.

We present a case of a 61-year-old female patient with ectopic corticotropin (ACTH) syndrome, hypopituitarism, and catecholamine excess due to a paraganglioma at the inferior pole of the left kidney. In this article we discuss the hormonal findings in the patient and its consequences, the pitfalls of the endocrine workup, and the results of our immunohistological and molecular studies in more detail.

Adrenocorticotropic Hormone↗
PubMed2006

Expression of connexins in chromaffin cells of normal human adrenals and in benign and malignant pheochromocytomas.

Decrease in connexin (Cx) expression and loss of gap junctional intercellular communication (GJIC) have been associated with aberrant cell growth and enhanced neoplastic phenotype. We studied the expression of Cx26, Cx32, Cx43, and Cx50 in chromaffin cells of 10 normal human adrenal glands, 10 benign, and 13 malignant pheochromocytomas. Immunohistochemistry showed that Cx50 expression seemed to be the predominant form of Cx expressed in human chromaffin cells, whereas Cx43 immunoreactivity was the most prominent form found in the adrenal cortex. However, Western blotting revealed that nonphosphorylated and singly and doubly phosphorylated forms of Cx43 were present within the malignant adrenomedullary cells at the same time. Cx26 and Cx32 were distributed inhomogeneously with no emphasis of expression in the types of tissues studied. Cx50 expression was diminished in malignant pheochromocytomas. We conclude that there is a differential expression of Cx in human adrenals. Immunohistological testing for Cx expression does not however allow differentiation of benign from malignant pheochromocytomas.

Adrenal Gland Neoplasms↗
PubMed2006

Autoimmune diagnostics in diabetes mellitus.

Type 1 diabetes results from a specific destruction of the insulin-producing beta-cells of the pancreas. The disease is characterized by the appearance of specific autoantibodies against islet cell antigens. Autoantibodies to insulin, glutamic acid decarboxylase, tyrosine phosphatase IA-2 and cytoplasmic islet cell antibodies are useful markers for the differential diagnosis of type 1 diabetes when clinical and metabolic criteria alone do not allow definite classification. Autoimmune diagnostics is of particular importance in adults to discriminate between type 1 and type 2 diabetes and to assess the diagnosis of latent autoimmune diabetes in adults.

Adult↗
PubMed2006

[Pharmacotherapy of obesity].

Long-term success in obesity therapy is difficult to obtain, therefore drug therapy appears to be helpful. Until today, end-point studies for obesity drugs beyond the improvement of individual surrogate parameters are still missing. For all available drugs, medical treatment can be recommended only for a limited period of time due to the data of the studies and under consideration of side effects. Although a weight reduction leads to an improvement of cardiovascular risk factors and hence a reduction of cardiovascular morbidity and mortality should be expected, no study could prove it so far. Despite the positive influence on individual surrogate parameters, the use of the present available therapies appears underwhelming. In this overview the approved substances and perspectives of new therapeutic concepts are represented.

Anti-Obesity Agents↗
PubMed2005

A pre-task resting condition neither 'baseline' nor 'zero'.

This study introduce the comparison of a 'reference state' versus a resting condition (zero), defined upon normative developmental equations. We compared pre-task 'resting' data from healthy individuals with the Normative Cuban digital resting EEG-database recently calculated for VARETA (qEEG/VARETA). The results allowed us to state that a 'pre-task resting conditions' exists as a state beyond the 'zero' or 'baseline' condition. The pre-task 'resting' condition is never truly 'at rest', however most of the previous published fMRI/PET studies assumed such a pre-task condition as reference/baseline condition. By defining different 'resting states' by qEEG/VARETA analyses, we have a potential methodology which can define resting state conditions and to be sure that they are consistent when comparing within group analyses across tasks or between groups either void of task or for task specific conditions.

Adult↗
PubMed2005

Chronic inflammation and hemodialysis reduce immune competence of peripheral blood leukocytes in end-stage renal failure patients.

Immunoincompetence is a profound problem in end-stage renal failure patients undergoing hemodialysis, and chronic inflammation with altered serum levels of inflammation markers has been reported. Gene expression patterns have had little relevance for leukocyte research so far because of limitations in transcript levels and stability. Using a new stimulation system we induced the expression of immune-relevant transcripts in whole blood preparations ex vivo and stabilized transcript levels by preventing RNA degradation and uncontrolled gene induction. Using quantitative real-time PCR we could show that basal TGF-beta mRNA expression is about 2-fold decreased in end-stage renal failure patients, while expression of TNF-alpha becomes 2-fold increased, further doubling during hemodialysis. By short term stimulation with phytohemagglutinin (PHA) for 2 h we tested for the immune competence of peripheral blood leukocytes and demonstrated that hemodialysis decreases TNF-alpha-mediated immune responsiveness more than 3-fold. This study shows by induction and stabilization of immune-relevant transcripts that chronic inflammation and hemodialysis are crucial factors for disturbed immune competence of end-stage renal failure patients.

Adult↗
PubMed2005

Thyrotropin receptor autoantibodies in Graves' disease.

Clinical thyrotoxicosis in Graves' disease patients is caused by thyrotropin receptor (TSHR)-stimulating autoantibodies. The molecular mechanisms of TSHR post-translational modification, TSHR signaling and TSHR-autoantibody interaction are still debatable, and the precise interaction of stimulating and blocking autoantibodies with TSHR is unclear. Recent TSHR epitope studies indicate that binding sites for stimulating and blocking autoantibodies are close together, not on distinct or distant parts of the molecule. Furthermore, new methods to detect TSHR autoantibodies and their clinical use are addressed. Highly sensitive TSHR autoantibody assays are widely available and cost efficient, and their routine clinical use might help in the differential diagnosis of hyperthyroidism and disease outcome prediction in patients with high levels of TSHR autoantibodies.

Autoantibodies↗
PubMed2005

Unlocking the opportunity of tight glycaemic control. Inhaled insulin: clinical efficacy.

Numerous attempts have been made to develop novel routes of insulin delivery that are both effective and tolerable. Of all the potential non-invasive delivery options, pulmonary delivery is the most clinically viable. Early studies demonstrate that the inhaled insulin is rapidly absorbed and is closer to biological insulin than standard subcutaneous insulin (SC). To date, inhaled insulin (Exubera) has been clinically assessed in more than 3500 patients with type 1 or type 2 diabetes, some treated for more than 7 years. Several phase 3 studies of 24-week duration have demonstrated comparable glycosylated haemoglobin (HbA1c) control in patients with type 1 diabetes treated with Exubera vs. SC insulin. Similar results have also been recorded in patients with type 2 diabetes. Furthermore, Exubera has shown clinical superiority to oral agent regimens in patients with type 2 diabetes who failed to achieve their target HbA1c using lifestyle modification and oral agents. Exubera was well tolerated and treatment satisfaction was high, with Exubera being the preferred insulin therapy in all studies. The results of these trials, and others, suggest that Exubera may be a valuable tool to help a wide variety of patients with type 1 or type 2 diabetes reach their recommended goals for glycaemic control, irrespective of their current therapy.

Administration, Inhalation↗
PubMed2005

Association of systemic chemokine concentrations with impaired glucose tolerance and type 2 diabetes: results from the Cooperative Health Research in the Region of Augsburg Survey S4 (KORA S4).

Chemokines are crucial immune mediators in many physiological and pathophysiological conditions. Chemokines have been hypothesized to be involved in macrophage infiltration into adipose tissue in obesity and might therefore play an important role in the development of obesity-related disorders like type 2 diabetes. Out of 1,653 individuals aged 55-74 years participating in a population-based survey in southern Germany (the Kooperative Gesundheitsforschung in der Region Augsburg [KORA] [Cooperative Health Research in the Region of Augsburg] Survey S4, 1999-2001), 236 individuals with type 2 diabetes, 242 subjects with impaired glucose tolerance (IGT), and 244 normoglycemic control subjects were studied for circulating concentrations of interleukin (IL)-8; RANTES (regulated on activation, normal T-cell expressed, and secreted); interferon-gamma-inducible protein-10 (IP-10), and eotaxin. Systemic concentrations of RANTES were higher in individuals with IGT or type 2 diabetes than in control subjects, whereas IL-8 levels were elevated in type 2 diabetic patients only (P < 0.001 for all comparisons). IP-10 and eotaxin were not significantly associated with IGT or type 2 diabetes. Adjustment for age, sex, BMI, hypertension, LDL cholesterol, HDL cholesterol, uric acid, C-reactive protein, and IL-6 did not alter these findings. Our findings indicate that RANTES and IL-8 may be involved in the development of type 2 diabetes independent of metabolic syndrome-related risk factors and of each other. There is no general upregulation of chemokine production in type 2 diabetes, but rather an association of the disease with specific members of the chemokine family.

Aged↗
PubMed2004

Impaired adrenal stress response in Toll-like receptor 2-deficient mice.

Septicemia is one of the major health concerns worldwide, and rapid activation of adrenal steroid release is a key event in the organism's first line of defense during this form of severe illness. The family of Toll-like receptors (TLRs) is critical in the early immune response upon bacterial infection, and TLR polymorphisms are frequent in humans. Here, we demonstrate that TLR-2 deficiency in mice is associated with reduced plasma corticosterone levels and marked cellular alterations in adrenocortical tissue. TLR-2-deficient mice have an impaired adrenal corticosterone release after inflammatory stress induced by bacterial cell wall compounds. This defect appears to be mediated by a decrease in systemic and intraadrenal cytokine expression, including IL-1, tumor necrosis factor alpha, and IL-6. Our data demonstrate a link between the innate immune system and the endocrine stress response. The critical role of TLR-2 in adrenal glucocorticoid regulation needs to be considered in patients with inflammatory disease.

Adrenal Cortex↗
PubMed2004

Insulin and the CNS: effects on food intake, memory, and endocrine parameters and the role of intranasal insulin administration in humans.

Insulin is mainly known for its peripheral effects on the metabolism of glucose, fats, and proteins. However, insulin also exerts important actions within the brain, and functions as a neuropeptide. The brain can thus be regarded as both an insulin-sensitive and a glucose-sensitive organ. Its neuroanatomical basis is the localization of insulin receptors, predominantly in the olfactory bulbs, hypothalamus, and hippocampus. Data obtained in animal experiments reveal an interesting insulin profile in the brain. Central insulin affects glucoregulation. As long as peripheral euglycemia is maintained, it was shown to reduce food intake and body weight and to improve learning and memory. Cognitive dysfunctions in dementia of the Alzheimer type (DAT) are associated with insulin deficiency within the brain, and memory improves in DAT patients when insulin levels increase. After describing these actions of insulin in the brain, we address here the transport of insulin into the brain. Insulin can either be transported from the periphery to the brain, or be administered directly into the brain. To reach insulin receptors directly, animals are typically administered insulin via the cerebral ventricles. For humans, the intranasal route is a practicable way to reach the brain while maintaining euglycemia. Additionally, the localization of insulin receptors in the olfactory bulb makes insulin interesting for the nose-to-brain pathway. Promising initial results have been reported with intranasally administered insulin corresponding to the diverse actions of insulin in the brain. Interestingly, initial data indicate that states of central insulin deficiencies (DAT and obesity) are accompanied by olfactory deviations. Thus, the nose-to-brain pathway deserves further attention.

Administration, Intranasal↗
PubMed2004

Evaluation of diagnostic relevance of mRNA levels in peripheral blood: predictive value for mortality in hemodialysis patients.

In clinical practice, diagnosis and risk prediction are usually based on the analysis of serum or plasma proteins whereas gene expression analysis is not used on a routine basis. In order to compare the diagnostic and predictive relevance of serum protein and peripheral blood mRNA levels, we determined cytokine levels of end-stage renal failure patients undergoing hemodialysis. These patients face a high mortality mainly due to acceleration of atherosclerosis and subsequent severe vascular events. mRNA expression of the pro-inflammatory cytokine TNF alpha was significantly elevated in hemodialysis patients and further increased after 2 h of dialysis treatment. In contrast, gene expression of the anti-inflammatory cytokine TGF beta was significantly decreased. Patients who died during the observation period of 36 months had significantly increased mRNA levels of TNF alpha and decreased TGF beta mRNA expression at baseline. Survival analysis indicated that increased TNF alpha mRNA levels (P < 0.02) and TNF alpha/TGF beta mRNA ratios (P < 0.001) predict mortality. The corresponding cytokines in serum showed some association with disease, but serum concentrations neither changed during hemodialysis nor predicted mortality. This study shows that gene expression patterns of circulating leukocytes may present an important new diagnostic tool to predict clinical outcome in patients with inflammatory vascular diseases.

Adult↗