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Biomedical subjects

A Wagner

Publications and source records attributed to A Wagner.

At least 73 records · Page 4Linked to original sources

Simulation of patient encounters using a virtual patient in periodontology instruction of dental students: design, usability, and learning effect in history-taking skills.

Simulations are important educational tools in the development of health care competence. This study describes a virtual learning environment (VLE) for diagnosis and treatment planning in oral health care. The VLE is a web-based, database application where the learner uses free text communication on the screen to interact with patient data. The VLE contains forms for history taking, clinical images, clinical data and X-rays. After reviewing the patient information, the student proposes therapy and makes prognostic evaluations of the case in free text. A usability test of the application was performed with seven dental students. The usability test showed that the software responded with correct answers to the majority of the free text questions. The application is generic in its basic functions and can be adapted to other dental or medical subject areas. A randomised controlled trial was carried out with 39 students who attended instruction in history taking with problem-based learning cases, lectures and seminars. In addition, 16 of the 39 students were randomly chosen to practise history taking using the virtual patient prior to their first patient encounter. The performance of each student was recorded on video during the patient sessions. The type and order of the questions asked by the student and the degree of empathy displayed towards the patient were analysed systematically on the videos. The data indicate that students who also undertook history taking with a virtual patient asked more relevant questions, spent more time on patient issues, and performed a more complete history interview compared with students who had only undergone standard teaching. The students who had worked with the virtual patient also seemed to have more empathy for the patients than the students who had not. The practising of history taking with a virtual patient appears to improve the capability of dental students to take a relevant oral health history.

Clinical Competence↗

Evaluation of aortic stenosis by cardiovascular magnetic resonance imaging: comparison with established routine clinical techniques.

OBJECTIVE: To evaluate whether direct planimetry of aortic valve area (AVA) by cardiac magnetic resonance (CMR) imaging is a reliable tool for determining the severity of aortic stenosis compared with transthoracic echocardiography (TTE), transoesophageal echocardiography (TOE), and cardiac catheterisation. METHODS: 44 symptomatic patients with severe aortic stenosis were studied. By cardiac catheterisation AVA was calculated by the Gorlin equation. AVA was measured with CMR from steady state free precession (true fast imaging with steady state precession) by planimetry. AVA was also determined from TOE images by planimetry and from TTE images by the continuity equation. RESULTS: Bland-Altman analysis evaluating intraobserver and interobserver variability showed a very small bias for both (-0.016 and 0.019, respectively; n = 20). Bias and limits of agreement between CMR and TTE were 0.05 (-0.35, 0.44) cm2 (n = 37), between CMR and TOE 0.02 (-0.39, 0.42) cm2 (n = 32), and between CMR and cardiac catheterisation 0.09 (-0.30, 0.47) cm2 (n = 36). The sensitivity and specificity of CMR to detect AVA < or = 0.80 cm2 measured by cardiac catheterisation was 78% and 89%, of TOE 70% and 70%, and of TTE 74% and 67%, respectively. CONCLUSION: CMR planimetry is highly reliable and reproducible. Further, CMR planimetry had the best sensitivity and specificity of all non-invasive methods for detecting severe aortic stenosis in comparison with cardiac catheterisation. Therefore, CMR planimetry of AVA with steady state free precession is a new powerful diagnostic tool, particularly for patients with uncertain or discrepant findings by other modalities.

Aged↗

Involvement of glucocorticoids in testicular involution after active immunization of boars against GnRH.

Active GnRH immunization of boars inhibits LH and testicular steroids but the consequences for spermatogenesis are unknown. Six boars were immunized three times against GnRH at 20, 24 and 28 weeks. Another six boars served as controls. Plasma LH and FSH were determined at 28 and 31 weeks. Testosterone and cortisol were determined before killing the pigs at 32 weeks. Tissue samples were taken for histology and fluid from the seminiferous tubuli for steroid determination. Individual germ cells were counted in histological sections. The glucocorticoid receptor (GCR), mitosis of spermatogonia and apoptosis were characterized by immunocytochemistry. Immunization reduced LH and testosterone to base levels whereas FSH was not changed. Testis weight was reduced by 64% due to a loss of Leydig cell cytoplasm (90.3%) and a decrease of tubule diameters (60.6%). Except for A-spermatogonia, all other spermatogenic cells were reduced by about 60%. Mitosis was reduced in immunized boars. Expression of GCRs was limited to spermatogonia and differed between immunized boars (8% of spermatogonia) and controls (2%). In the controls, androgen concentrations in tubular fluid were tenfold higher compared with immunized boars. Cortisol concentrations were of the order of 40 nmol/l both in the tubular fluid and blood plasma. These concentrations did not differ between groups. Apoptosis occurred only in spermatogonia and pachytene spermatocytes and was twofold higher in immunized boars compared with controls. Thus the availability of glucocorticoids in the tubuli and the expression of GCRs initiate apoptosis, which in turn reduces sperm yield. Testosterone is known to be an inhibitor of GCR expression, thus increasing the efficiency of spermatogenesis.

Animals↗

The association of metabolic disorders with the metabolic syndrome is different in men and women.

AIMS: Metabolic disorders depend on genetic, hormonal and environmental factors, whose relations may differ between genders. Therefore, we compared the contribution of metabolic disorders to the metabolic syndrome in women and men. METHODS: To this end, we used a hierarchical classification statistical method to classify subjects into similarity groups according to clinical and biological parameters. Data were collected from 3,508 men and women aged 35-64 years, from a cardiovascular disease survey. RESULTS: In both women and men, hierarchical classification identified a cluster corresponding to the metabolic syndrome representing 14 and 15% of the women's and men's sample, respectively. In women, elevated body weight (women's Z-score: 1.59 vs. men's Z-score: 1.29; p < 0.005), waist girth (1.62 vs. 1.30; p < 0.001) and low HDL cholesterol (-0.95 vs. -0.75; p < 0.05) were significantly larger contributors to the metabolic syndrome than in men. In contrast, systolic (0.59 vs. 0.95; p < 0.0001) and diastolic (0.55 vs. 0.99; p < 0.0001) blood pressure and apolipoprotein B (0.51 vs. 0.71; p < 0.0001) contributed significantly less in women than in men. Finally, insulin (n.s.), glucose (n.s.), triglycerides (n.s.) and LDL-cholesterol (n.s.) contributions were not different between genders. CONCLUSION: These results are consistent with the concept that a clustering of metabolic disorders occurs frequently in both women and men. However, the contribution of several metabolic disorders to the metabolic syndrome is different in men and women. This finding supports the concept that different criteria are necessary to define the metabolic syndrome in women and men.

Adult↗

First evidence for different freeze-out conditions for kaons and antikaons observed in heavy-ion collisions.

Differential production cross sections of K- and K+ mesons have been measured in Ni+Ni and Au+Au collisions at a beam energy of 1.5 A GeV. The K(-)/K(+) ratio is found to be nearly constant as a function of the collision centrality and system size. The spectral slopes and the polar emission pattern differ for K- and K+ mesons. These observations indicate that K+ mesons decouple earlier from the fireball than K- mesons.

Journal Article↗

Malignant germ cell tumours of the testis express interferon-gamma, but are resistant to endogenous interferon-gamma.

Cytokines possess discrepant effects on tumour cells varying from anti- to proapoptotic activities. We recently reported that testicular germ cell tumours (TGCT) express a functional form of the proinflammatory cytokine interferon-gamma (IFNgamma). The present study asked whether TGCT-derived IFNgamma influences survival or death of neoplastic germ cells. Analysis of TGCT cell lines demonstrated that they expressed and secreted IFNgamma, but were resistant to the endogenous IFNgamma since neutralisation of IFNgamma by a specific blocking antibody had no influence on the proliferation and/or the degree of apoptosis of tumour cells. To study mechanisms providing tumour resistance to endogenous IFNgamma, we analysed primary TGCT and two human TGCT cell lines (NTERA and NCCIT) for the expression of IFNgamma receptor and for the level of phosphorylation of the signal transducer and activator of transcription (STAT)-1. In situ hybridisation, immunocytochemistry, Western blot analysis and flow cytometry indicated that primary TGCT as well as NCCIT and NTERA cell lines expressed the heterodimeric cell surface IFNgamma receptor which consists of both 90-kDa alpha- and the 85-kDa beta-chains. However, the downstream transcription factor STAT-1 was not phosphorylated constitutively, indicating that STAT-1 is not activated by the endogenous IFNgamma. Upon application of recombinant human IFNgamma in excess, however, STAT-1 was phosphorylated and the interferon regulatory factor-1 (IRF-1) was induced, suggesting that both IFNgammaR and STAT-1 are functionally intact in TGCT. Altogether our results suggest that despite secreting biologically active IFNgamma, the concentration of the endogenous IFNgamma is too low to stimulate the IFNgammaR/STAT signalling pathway in TGCT in an autocrine and/or paracrine manner.

Apoptosis↗

Influence of mistletoe ( Viscum album) extracts on phagocytosis/burst activity of human phagocytes.

The aim of the present study was to examine the in vitro effects of various mistletoe extracts on human phagocytes. Phagocytosis, oxidative burst, and intracellular killing were analyzed by flow cytometry. None of the mistletoe preparations investigated exhibited significant phagocytosis-enhancing properties. Different mistletoe lectin concentrations ranging from 0.025 to 20 ng/ml showed only marginal influence on phagocyte activity. Contrary to the opinion of numerous practitioners of complementary medicine, the mistletoe preparations tested do not enhance phagocytic function.

Candida albicans↗

Coulomb dissociation of 8B and the low-energy cross section of the 7Be(p,gamma)8B solar fusion reaction.

An exclusive measurement of the Coulomb breakup of 8B into 7Be+p at 254A MeV allowed the study of the angular correlations of the breakup particles. These correlations demonstrate clearly that E1 multipolarity dominates and that E2 multipolarity can be neglected. By using a simple single-particle model for 8B and treating the breakup in first-order perturbation theory, we extract a zero-energy S factor of S17(0)=18.6+/-1.2+/-1.0 eV b, where the first error is experimental and the second one reflects the theoretical uncertainty in the extrapolation.

Journal Article↗

Differential expression of IFN-alpha subtypes in human PBMC: evaluation of novel real-time PCR assays.

Studies of the human IFN-alpha subtype system have been hampered by the lack of efficient procedures to quantify and differentiate the expression of the highly homologous IFN-alpha subtypes. Here we evaluate four novel real-time PCR assays for the specific detection and quantification of IFN-alpha mRNA for the subtypes alpha(2), alpha(6), alpha(8) and alpha(1/13) in a combined assay in human peripheral blood mononuclear cells (PBMC). This included (a) the selection of beta-glucuronidase (GUS) as a suitable housekeeping gene for relative quantification; (b) verification of the specificity by using human DNA of different IFN-alpha subtypes; and (c) comparison of the amplification efficiencies among the different assays. This highly sensitive method allows the detection of low-level, constitutive IFN-alpha mRNA and shows differences in the composition of constitutive IFN-alpha subtypes compared to other cell types (HeLa and HEp-2). The in vitro stimulation of PBMC with Newcastle disease virus (NDV), Respiratory syncytial virus (RSV) or an inactivated Herpes simplex (HSV) preparation leads to the transcriptional induction of all IFN-alpha subtypes investigated but to different expression levels. Among the subtypes detected, IFN-alpha(13/1) and alpha(2) are the major transcripts followed by alpha(8), and finally alpha(6) as a minor transcribed subtype. Time-kinetics of IFN-alpha transcriptional activation also revealed variations in the course of IFN-alpha transcription between NDV, RSV or HSV. The data obtained from the real-time PCR assays correlated well with IFN-alpha(2) protein release. In conclusion, we have demonstrated the suitability and reliability of new real-time PCR assays for the rapid and efficient analysis of IFN-alpha subtype expression.

Animals↗

Phase separation in binary fluid mixtures with continuously ramped temperature.

We consider the demixing of a binary fluid mixture, under gravity, which is steadily driven into a two-phase region by slowly ramping the temperature. We assume, as a first approximation, that the system remains spatially isothermal, and we examine the interplay of two competing nonlinearities. One of these arises because the supersaturation is greatest far from the meniscus, creating inversions of the density which can lead to fluid motion; although isothermal, this is somewhat like the Bénard problem (a single-phase fluid heated from below). The other is the intrinsic diffusive instability which results either in nucleation or in spinodal decomposition at large supersaturations. Experimental results on a simple binary mixture show interesting oscillations in heat capacity and optical properties, for a wide range of ramp parameters. We argue that these oscillations arise under conditions where both nonlinearities are important.

Journal Article↗

[Electrophysiological impairment profile of patients with Wilson's disease].

In addition to hepatic and extrapyramidal motor clinical symptoms, Wilson's disease patients also exhibit subclinical disorders of other central nervous pathways. In this study, an impairment profile is described by means of eight electrophysiological tests (EAEP, MSEP, TSEP, T-VEP, MEP, EEG, heart frequency variability, and SSR) for 37 patients (28 with neurological, nine with tnon-neurological form) undergoing long-term drug therapy. The occurrence in 64.3% of a delayed wave III and/or IPL III-V prolongation in patients with the neurological form makes pathological FAEP the most common form of the disorder, followed by disorders in MSEP, TSEP, MEP, and T-VEP. Patients with the non-neurological form usually have normal values, although latency prolongations occur in isolated cases. The range of evoked potential findings is characterised primarily by latency prolongations, i.e. a demyelinising impairment type, and significant losses of potential hardly occur (except in the MEP). The electrophysiological impairment profile does not include EEG changes or vegetative disorders.

Autonomic Nervous System Diseases↗

The degree of depression in Hamilton rating scale is correlated with the density of presynaptic serotonin transporters in 23 patients with Wilson's disease.

OBJECTIVE: One of the most frequent psychiatric symptoms in patients with Wilson's disease (WD) is depression. It has been suggested that depression is associated with deficits in serotonergic neurotransmission, but, hitherto, no measurements have been performed in WD. METHODS: We prospectively examined 23 adult patients (12 women, 11 men, mean age 40 years) with WD for symptoms of depression using the Hamilton rating scale for depression (HAMD). We correlated the data with the presynaptic serotonin transporter density (SERT density) in the thalamus-hypothalamus and the midbrain-pons regions measured with high resolution single-photon emission computed tomography (SPECT) 24 hours after the application of 180 MBq 2beta-carbomethoxy-3beta-(4 [(123)I]iodophenyl)tropane ( [(123)I]b-CIT). The regions of interest were determined by coregistration with a standard MRI dataset. RESULTS: A significant negative correlation was found between HAMD and SERT density in the thalamus-hypothalamus region (r = -0.49, p = 0.02), but not in the midbrain-pons (r = -0.31, p = 0.15). CONCLUSIONS: We conclude that depression in patients with Wilson's disease is correlated with alterations of serotonergic neurotransmission in the thalamus-hypothalamus region.

Adult↗

Regional serotonin transporter availability and depression are correlated in Wilson's disease.

In patients with Wilson's disease (WD), depression is a frequent psychiatric symptom. In vivo neuroimaging studies suggest that depression and other neuropsychiatric disorders are associated with central serotonergic deficits. However, in vivo measurements of serotonergic neurotransmission have not until now been performed in patients with this copper deposition disorder. The present prospective study revealed that depressive symptomatology is related to an alteration of presynaptic serotonin transporters (SERT) availability as measured by [123I]-2beta-carbomethoxy-3beta-(iodophenyl)tropane ([123I]beta-CIT) and high-resolution single-photon emission computed tomography (SPECT). SERT imaging with [123I]beta-CIT-SPECT could therefore become a useful tool for diagnosis and therapy monitoring in depressed WD patients.

Adult↗

Investigation of fine-motor disturbances in Wilson's disease.

Patients suffering from Wilson's disease (WD) can be divided into two main subgroups: neurologic and nonneurologic WD. We measured passive and active fine-motor abilities of 37 WD patients and 24 randomly selected volunteers. The measurement was based on a standardized test set in a defined environment for detection of disturbed finemotor control. The set contains 5 tests comprising rest tremor, postural tremor, target tapping, forefinger tapping and spiral painting, reflecting different aspects of movement disorders. The tests showed significant differences between neurologic WD and volunteers, especially for tasks defining active control. In neurologic WD we found no differences between subgroups whereas for non-neurologic WD we often detected slight movement disorders. The detected movement disorders cam be interpreted as persistent disorders after long-term therapy.

Adult↗

Early biochemical and histological alterations in rat corticoencephalic cell cultures following metabolic damage and treatment with modulators of mitochondrial ATP-sensitive potassium channels.

The present study was aimed at characterizing alterations of the nucleotide content and morphological state of rat corticoencephalic cell cultures subjected to metabolic damage and treatment with modulators of mitochondrial ATP-dependent potassium channels (mitoK(ATP)). In a first series of experiments, in vitro ischemic changes of the contents of purine and pyrimidine nucleoside diphosphates and triphosphates were measured by high performance liquid chromatography (HPLC) and the corresponding histological alterations were determined by celestine blue/acid fuchsin staining. As an ischemic stimulus, incubation with a glucose-free medium saturated with argon was used. Ischemia decreased the levels of adenosine, guanine and uridine triphosphate (ATP, GTP, UTP) and increased the levels of the respective dinucleotides ADP and UDP, whereas the GDP content was not changed. Both 5-hydroxydecanoate (5-HD) and diazoxide failed to alter the contents of nucleoside diphosphates and triphosphates, when applied under normoxic conditions. 5-HD (30 microM) prevented the ischemia-induced changes of nucleotide and nucleoside levels. Diazoxide (300 microM), either alone or in combination with 5-hydroxydecanoate (30 microM) was ineffective. Pyruvate (5 mM) partially reversed the effects of ischemia or ischemia plus 2-deoxyglucose (20mM) in the incubation medium. Diazoxide (300 microM) and 5-HD (30 microM) had no effect in the presence of pyruvate (5mM) and 2-deoxyglucose (20mM). Staining the cells with celestine blue/acid fuchsin in order to classify them as intact, reversibly or profoundly injured, revealed a protective effect of 5-HD. When compared with 5-HD, diazoxide, pyruvate and 2-deoxyglucose had similar but less pronounced effects. In conclusion, these results suggest a protective role of 5-hydroxydecanoate on early corticoencephalic nucleotide and cell viability alterations during ischemia.

ATP-Binding Cassette Transporters↗

[Funnel chest: filling technique with deep custom made implant].

Through 97 patients over 9 years, the authors present a surgical treatment for "funnel chest" using custom-made silicone elastomer prothesis which are deeply placed, behind muscle and aponevroses. They justify the choice of this simple and non invasive technique, by the fact that this deformation is only morphological in most cases or even only inaesthetic with exceptional cardiac or pulmonary consequences. Patient's motivation being mainly due to psychological disconfort, the non invasive aspect of the technique leads them to choose surgery, particularly as results are good and complications seldom.

Adolescent↗