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D Simon

Publications and source records attributed to D Simon.

At least 37 records · Page 2Linked to original sources
PubMed2004

Understanding the high activity of a nanostructured catalyst obtained by a deposit of Pd on Ni: first principle calculations.

The catalytic activity of a 4 monolayer deposit of Pd on a Ni(110) surface toward the hydrogenation of ethylene is investigated by using gradient-corrected periodic density functional calculations. The Pd/Ni(110) surface is strongly nanostructured, due to the anisotropic stress induced by the Ni(110) substrate on the Pd layer. A kinetic analysis, based on the investigation of the optimal reaction pathway for the hydrogenation of ethylene to ethane, is presented, allowing a comparison between Pd/Ni(110) and pure Pd(110) surfaces. The calculated activation energies allow one to reproduce the experimental result, which shows that the Pd/Ni(110) surface is about 30 times more active than the pure Pd(110) surface. This marked increase of the catalytic activity is a consequence of the specific nanostructure of the Pd/Ni(110) surface. By examining the structure of the adsorbed species and of the transition states and by analyzing the electronic properties, we show that this rate increase can be associated to the fact that the ethylene adsorption energy in the first hydrogenation step and the ethyl-hydrogen coadsorption energy in the second step are both much lower on Pd/Ni(110) than on pure Pd(110).

Journal Article↗
PubMed2004

[Development and evaluation of a training program in shared decision making for primary care of depressive patients].

Patient surveys show that many patients want broad information about their disease and treatment. Often they are interested to participate in the process of medical decision making, which could be realised with the concept of shared decision making where patient's values and needs are considered to the same extent as the treatment recommendations of evidence-based medicine. In depression care, it has been demonstrated so far that the active involvement of patients contributes to higher motivation for treatment. For enhancing patient's acceptance and motivation to avail themselves of medical treatment, a training program for general practitioners was developed and evaluated. It was the aim of the training to involve depressive patients in medical decision making. The training consists of depression-specific components (e. g. diagnosis, patient information, therapy) and general components (communication and shared decision making). The training was carried out in five sessions within a 6-month period (May to October 2003) embracing 20 h of training. Participants were 20 general practitioners in Southwest Germany. Physician's satisfaction with the training program is high. Especially in the fields of diagnosis and shared decision making the physicians clearly benefited. Transfer of shared decision making into daily routine was assessed as possible by the large majority of the trainees. Application of the training concept to other diseases and evaluation on the basis of daily routine is recommended. The training effects on medical care are presently being assessed in a randomised controlled trial.

Adult↗
PubMed2004

The dominant alopecia phenotypes Bareskin, Rex-denuded, and Reduced Coat 2 are caused by mutations in gasdermin 3.

Reduced Coat 2 (Rco2) is an ENU-induced mutation affecting hair follicle morphogenesis by an abnormal and protracted catagen. We describe chromosomal mapping and molecular identification of the autosomal dominant Rco2 mutation. The Rco2 critical region on mouse chromosome 11 encompasses the alopecia loci, Bareskin (Bsk), Rex-denuded (Re(den)), Recombination induced mutation 3 (Rim3), and Defolliculated (Dfl). Recently, the gasdermin (Gsdm) gene was described as predominantly expressed in skin and gastric tissues. We provide evidence for a murine-specific gene cluster consisting of Gsdm and two closely related genes which we designate as Gsdm2 and Gsdm3. We show that Gsdm3 reflects a mutation hotspot and that Gsdm3 mutations cause alopecia in Rco2, Re(den), and Bsk mice. We infer a role of Gsdm3 during the catagen to telogen transition at the end of hair follicle morphogenesis and the formation of hair follicle-associated sebaceous glands.

Alleles↗
PubMed2004

Pheochromocytoma during pregnancy: laparoscopic and conventional surgical treatment of two cases.

Pheochromocytoma is a rare entity. When it presents during pregnancy, rapid recognition and diagnosis are crucial in order to avoid the maternal and fetal morbidity and mortality associated with severe, uncontrolled hypertension. Difficulties arise from the differential diagnosis of pre-eclampsia. We report two patients operated on for pheochromocytoma during pregnancy. The first patient developed new-onset hypertension in early pregnancy. Prior to presentation, there had been non-specific signs of endocrine disorder, namely a mild diabetes, but no hypertension requiring medication. The second patient sought medical care for irregular heartbeat, shortness of breath, and fatigue during the 6th week of pregnancy. She was found to be hypertensive; diagnostic evaluation revealed substantially increased catecholamine levels. The diagnosis was made by elevated urinary catecholamines and by MRI scan as well as ultrasonography, both of which demonstrated an adrenal mass. Both patients underwent surgical extirpation of the affected adrenal gland. The procedure was performed laparoscopically in the case of the second patient. Pre-operatively, both patients were pre-treated with alpha-blockade followed by secondary beta-blockade. Patient two also received methyldopa for control of hypertension. Both patients were readily weaned from antihypertensive medications post-operatively, with complete resolution of hypertension within a few hours. Each pregnancy progressed normally to term.

Adrenal Gland Neoplasms↗
PubMed2004

Eosinophils and atopic dermatitis.

In spite of the progress regarding the description of immunological phenomena associated with atopic dermatitis (AD), the pathogenesis of this disease still remains unclear. The presence of eosinophils in the inflammatory infiltrate of AD has long been established. Eosinophil numbers as well as eosinophil granule protein levels in peripheral blood are elevated in most AD patients and appear to correlate with disease activity. Moreover, eosinophil granule proteins, which possess cytotoxic activity, are deposited in the skin lesions. These observations indicate a role of eosinophils in the pathogenesis of AD. Furthermore, AD is associated with increased production of T helper 2 cytokines including interleukin (IL)-5, which specifically acts on eosinophils, resulting in accelerated eosinophilopoiesis, chemotaxis, cell activation, and delayed apoptosis. Therefore, IL-5 is an interesting target for experimental therapy in this inflammatory disorder of the skin. Such studies might result in new insights into the pathogenetic role of eosinophils in AD.

Chemokine CCL11↗
PubMed2004

The prevalence of positive reactions in the atopy patch test with aeroallergens and food allergens in subjects with atopic eczema: a European multicenter study.

BACKGROUND: The atopy patch test (APT) was proposed to evaluate IgE-mediated sensitizations in patients with atopic eczema (AE). OBJECTIVE: The prevalence and agreement with clinical history and specific IgE (sIgE) of positive APT reactions was investigated in six European countries using a standardized method. METHODS: A total of 314 patients with AE in remission were tested in 12 study centers on clinically uninvolved, non-abraded back skin with 200 index of reactivity (IR)/g of house dust mite Dermatophagoides pteronyssinus, cat dander, grass, and birch pollen allergen extracts with defined major allergen contents in petrolatum. Extracts of egg white, celery and wheat flour with defined protein content were also patch tested. APT values were evaluated at 24, 48, and 72 h according to the European Task Force on Atopic Dermatitis (ETFAD) guidelines. In addition, skin-prick test (SPT) and sIgE and a detailed history on allergen-induced eczema flares were obtained. RESULTS: Previous eczema flares, after contact with specific allergens, were reported in 1% (celery) to 34% (D. pteronyssinus) of patients. The frequency of clear-cut positive APT reactions ranged from 39% with D. pteronyssinus to 9% with celery. All ETFAD intensities occured after 48 and 72 h. Positive SPT (16-57%) and elevated sIgE (19-59%) results were more frequent. Clear-cut positive APT with all SPT and sIgE testing negative was seen in 7% of the patients, whereas a positive APT without SPT or sIgE for the respective allergen was seen in 17% of the patients. APT, SPT and sIgE results showed significant agreement with history for grass pollen and egg white (two-sided Pr > /Z/ < or = 0.01). In addition, SPT and sIgE showed significant agreement with history for the other aeroallergens. With regard to clinical history, the APT had a higher specificity (64-91% depending on the allergen) than SPT (50-85%) or sIgE (52-85%). Positive APT were associated with longer duration of eczema flares and showed regional differences. In 10 non-atopic controls, no positive APT reaction was seen. CONCLUSION: Aeroallergens and food allergens are able to elicit eczematous skin reactions after epicutaneous application. As no gold standard for aeroallergen provocation in AE exists, the relevance of aeroallergens for AE flares may be evaluated by APT in addition to SPT and sIgE. The data may contribute to the international standardization of the APT.

Adolescent↗
PubMed2004

Improving glycaemic control of patients with Type 2 diabetes in a primary care setting: a French application of the Staged Diabetes Management programme.

AIMS: To assess the impact of a French adaptation of the Staged Diabetes Management (SDM) programme on glycaemic control of people with Type 2 diabetes in primary care. Secondary endpoints were blood pressure, blood lipids, healthcare costs and quality of life. METHODS: Prospective, randomized controlled study, of 1 years' duration. General practitioners (GPs) were recruited in four separate districts of a French region. They enrolled consecutive patients with Type 2 diabetes. GPs in the intervention group were educated in the SDM programme. GPs in the control group were asked to provide usual care. Healthcare costs were collected by medical departments of the Health Insurance systems. Quality of life was assessed with the Duke Health Profile. RESULTS: Three hundred and forty patients enrolled by 57 GPs completed the study, 192 in the intervention group and 148 in the control group. Patients in the intervention group were managed more adequately in accordance with the guidelines (P < 0.05 for nine out of 10 items). HbA(1c) decreased by 0.31% in the intervention group and increased by 0.56% in the control group, resulting in a difference of 0.87% by the end of the study (P = 0.001). Blood pressure and blood lipids did not differ between groups. Occurrence of major complications was low and identical in both groups. Incremental costs during the study in the intervention group were 35 euros per patient per month, and this was not significantly different in comparison with the control group. Quality of life was not affected by the intervention. CONCLUSIONS: Educating GPs in the French adaptation of the SDM programme improves glycaemic control in a primary care setting, without significantly increasing healthcare costs.

Blood Glucose↗
PubMed2003

Association studies between -1185A/G von Willebrand factor gene polymorphism and coronary artery disease.

High levels of von Willebrand factor (vWF) have been associated with cardiovascular disease. The A allele of the -1185A/G polymorphism in the 5'-regulatory region of the vWF gene was associated with the highest plasma vWF levels in a normal population. To examine the association between -1185A/G polymorphism and coronary artery disease (CAD), 173 Brazilian Caucasian subjects submitted to coronary angiography were studied. Of these, 57 (33%) had normal coronary arteries (control group) and 116 (67%) had CAD (patient group). Plasma vWF levels were higher in patients (145 U/dl) than in controls (130 U/dl), but the differences were significant only for O blood group subjects. Polymerase chain reaction amplification of the 864-bp vWF promoter region followed by AccII restriction digestion was used to identify the -1185A/G genotypes. The -1185A allele frequency was 43.1% in patients and 44.7% in controls. Allele and genotype frequencies were not significantly different between patients and controls. No association was observed between the -1185A/G genotypes and plasma vWF levels in patients or controls. These results suggest that -1185A/G polymorphism is not an independent risk factor for CAD.

Adult↗
PubMed2003

High diagnostic accuracy of adrenal core biopsy: results of the German and Austrian adrenal network multicenter trial in 220 consecutive patients.

Incidentally detected adrenal tumors are a common finding during abdominal ultrasonography, computed tomography, and magnetic resonance imaging. Although most of these lesions are benign adenomas, adrenocortical carcinomas and metastases constitute 5% to 10% of all tumors. Adrenal biopsy may be helpful, but its diagnostic value is controversial and disputed, and prospective studies have not yet been performed. Therefore, the diagnostic accuracy of adrenal core biopsy was evaluated in a prospective multicenter study involving 8 surgical centers in Germany and Austria. A total of 220 biopsies from surgical specimens of the adrenal gland were punctured in an ex vivo approach and processed for pathohistologic diagnosis using paraffin sections, routine staining, and immunohistochemistry (keratin KL1, vimentin, S100 protein, chromogranin A, synaptophysin, neuron-specific enolase, D11, MiB-1, and p53 protein). The evaluating pathologist was blinded for clinical data from the patients. A total of 89 adrenal adenomas (40.5%), 22 adrenal carcinomas (10.0%), 55 pheochromocytomas (25.0%), 15 metastases (6.8%), 16 adrenal hyperplasias (7.2%), and 23 other tumors (10.5%) were studied. Nine cases were excluded due to incomplete data (n = 2) or insufficient biopsy specimen (n = 7). In the remaining 211 tumors, compared with the final diagnoses of the surgical specimen, bioptic diagnoses were absolutely correct in 76.8% of the cases, nearly correct in 13.2% of the cases, and incorrect in 10% of the cases. Pheochromocytomas were correctly diagnosed in 96% of the cases, cortical adenomas were correctly or nearly correctly reported in 91% of the cases, cortical carcinomas were correctly or nearly correctly reported in 76% of the cases, and metastases were correctly or nearly correctly reported in 77% of the cases. Of the 39 malignant lesions, only 4 were misclassified, 2 as benign and 2 as possibly malignant. This resulted in an overall sensitivity for malignancy of 94.6% and specificity of 95.3%. Our findings suggest that adrenal core biopsy is a useful method for identifying and classifying adrenal tumorous lesions if sufficient biopsy specimens can be obtained. However, in clinical practice it remains to be shown whether the benefits of biopsy outweigh the risks of the procedure.

Adenoma↗
PubMed2002

Highly strained structure of a four-layer deposit of Pd on Ni(110): a coupled theoretical and experimental study.

The structure of a four monolayer deposit of Pd on Ni(110) has been determined by a combination of x-ray diffraction experiments and density-functional theory calculations. This Pd film presents, after annealing at 500 K, a (Nx2) reconstruction associated with a large enhancement of its catalytic activity. The N superstructure, along the dense [11;0] direction, comes from periodic edge dislocations initiated by a vacancy in the first Pd layer. In the perpendicular direction, the doubling of the period originates in a pairing-buckling displacement of the rows. This study evidences a new Pd atoms arrangement with quasi-four-fold hollow sites on the surface, which could play an important role in the exceptional catalytic activity.

Journal Article↗
PubMed2002

Clinical impact of retinoids in redifferentiation therapy of advanced thyroid cancer: final results of a pilot study.

Differentiated thyroid cancer is a malignant tumour that has a fairly good prognosis, with patients surviving for many years. Multimodal therapy with surgery, radioiodine therapy and TSH suppressive medication is of proven efficacy. However, loss of differentiation is observed in up to one-third of patients with differentiated thyroid cancer, paralleled by an increase in tumour grading and loss of thyroid-specific functions (thyrotropin receptor, iodine accumulation). Such tumours may no longer be amenable to standard treatment protocols, including TSH suppression and radioiodide therapy. Retinoic acids have been shown to exert re-differentiating effects on thyrocytes in various experimental studies and case reports, and it was on this basis that this pilot study was initiated. Patients with advanced thyroid cancer and without the therapeutic options of operation or radioiodide therapy were treated with 13- cis-retinoic acid at a dosage of 1.5 mg/kg body weight daily over 5 weeks. Parameters for assessment of the therapeutic effect were serum thyroglobulin (TG) levels, radioiodine uptake, and tumour size prior to and after retinoid treatment. Fifty patients were evaluated for response, classified as reduction in tumour size and TG levels, stable disease or disease progression. Thirteen patients showed a clear increase in radioiodine uptake, and eight a mild increase. TG levels were unchanged or decreased in 20 patients. Tumour size was assessable in 37 patients; tumour regression was observed in six, and there was no change in 22. In total, a response was seen in 19 patients (38%). Response to retinoid therapy did not always correlate with increased radioiodine uptake, so other direct antiproliferative effects have to be assumed. The encouraging results of the study and the low rate of side-effects with good tolerability of retinoids warrant further studies with altered inclusion criteria and employment of other redifferentiating drugs or combinations of agents.

Adenocarcinoma↗
PubMed2002

Peripheral blood mononuclear cells from IgE- and non-IgE-associated allergic atopic eczema/dermatitis syndrome (AEDS) demonstrate increased capacity of generating interleukin-13 but differ in their potential of synthesizing interferon-gamma.

BACKGROUND: A subgroup of patients with allergic atopic eczema/dermatitis syndrome (AEDS) are known to have normal total and specific IgE levels and negative skin prick tests towards common environmental allergens. This form of the disease has been termed non-IgE-associated allergic AEDS. Although allergic mechanisms appear to be important, the pathogenesis of both IgE- and non-IgE-associated forms of the disease is unknown. METHODS: We have compared the cytokine production pattern of peripheral blood mononuclear cells (PBMC) from IgE-associated AEDS, non-IgE-associated AEDS, and normal control individuals. PBMC were stimulated with anti-CD3 and/or anti-CD28 monoclonal antibodies (mAb) and cytokine production was measured by immunoassays in supernatants of 24-h cultures. RESULTS: Compared to healthy subjects and non-IgE-associated AEDS patients, stimulated PBMC from IgE-associated AEDS patients produced less interferon (IFN)-gamma. However, stimulated PBMC from both IgE-associated AEDS and non-IgE-associated AEDS patients produced more interleukin (IL)-13 than PBMC from control individuals. Moreover, IL-5 production was significantly increased in non-IgE-associated AEDS but not in IgE-associated AEDS patients. CONCLUSIONS: The underlying mechanism leading to increased differentiation of T helper (Th) 2 cells may involve a deficient capacity in producing IFN-gamma in IgE-associated AEDS but not in non-IgE-associated AEDS patients. IL-13 may be a key cytokine in the pathogenesis of both allergic forms of AEDS.

Adult↗