Browsing by Author "Fischer, Thomas"

Four possible precursors of 1-phenyl-1,2-cyclohexadiene (2) were examined, namely, 6,6-dibromo-1-phenylbicyclo[3.1.0]hexane, (1 alpha,5 alpha,6 alpha)-6-bromo-6-fluoro-1-phenylbicyclo-[3.1.0]hexane, 1-bromo-2-phenylcyclohexene and 1-bromo-6-phenylcyclohexene. All four compounds could be converted into 2, as demonstrated by the products of the interception of 2 with activated olefins. Styrene, 1,1-diphenyl-ethene, indene, furan and 2,5-dimethylfuran were employed as such. Whereas the first three gave [2+2] cycloadducts of 2, the last two provided one [4+2] cycloadduct each. To create the [2+2] cycloadducts, the it bond of 2 that is more remote from the phenyl group reacted, whereas the pi bond of 2 conjugated with the phenyl group exclusively produced the [4+2] cycloadducts. The generation of 2 in the absence of a trapping reagent brought about relatively good yields of a dimer or a trimer of 2 depending on the mode of the liberation of 2. Being derivatives of triphenylene, the dimer as well as the trimer have unusual structures, thereby indicating that a phenyl group is participating in the formation of these compounds. The most surprising structure of the trimer was elucidated by X-ray crystal diffraction. As to the mechanisms, diradical intermediates are proposed both for the cycloadditions and for the dimerisation. The initial steps of the latter seem to proceed also in the trimerisation.

CONTEXT The dissemination of objective structured clinical examinations (OSCEs) is hampered by requirements for high levels of staffing and a significantly higher workload compared with multiple-choice examinations. Senior medical students may be able to support faculty staff to assess their peers. The aim of this study is to assess the reliability of student tutors as OSCE examiners and their acceptance by their peers. METHODS Using a checklist and a global rating, teaching doctors (TDs) and student tutors (STs) simultaneously assessed students in basic clinical skills at 4 OSCE stations. The inter-rater agreement between TDs and STs was calculated by kappa values and paired t-tests. Students then completed a questionnaire to assess their acceptance of student peer examiners. RESULTS All 214 Year 3 students at the University of Gottingen Medical School were evaluated in spring 2005. Student tutors gave slightly better average grades than TDs (differences of 0.02-0.20 on a 5-point Likert scale). Inter-rater agreement at the stations ranged from 0.41 to 0.64 for checklist assessment and global ratings; overall inter-rater agreement on the final grade was 0.66. Most students felt that assessment by STs would result in the same grades as assessment by TDs (64%) and that it would be similarly objective (69%). Nearly all students (95%) felt confident that they could evaluate their peers themselves in an OSCE. CONCLUSIONS On the basis of our results, STs can act as examiners in summative OSCEs to assess basic medical skills. The slightly better grades observed are of no practical concern. Students accepted assessment performed by STs.

Background Although it is taken for granted that history-taking and communication skills are learnable, this learning process should be confirmed by rigorous studies, such as randomized pre- and post-comparisons. The purpose of this paper is to analyse whether a communication course measurably improves the communicative competence of third-year medical students at a German medical school and whether technical or emotional aspects of communication changed differently. Method A sample of 32 randomly selected students performed an interview with a simulated patient before the communication course (pre-intervention) and a second interview after the course (post-intervention), using the Calgary-Cambridge Observation Guide (CCOG) to assess history taking ability. Results On average, the students improved in all of the 28 items of the CCOG. The 6 more technically-orientated communication items improved on average from 3.4 for the first interview to 2.6 in the second interview (p < 0.0001), the 6 emotional items from 2.7 to 2.3 (p = 0.023). The overall score for women improved from 3.2 to 2.5 (p = 0.0019); male students improved from 3.0 to 2.7 (n.s.). The mean interview time significantly increased from the first to the second interview, but the increase in the interview duration and the change of the overall score for the students’ communication skills were not correlated (Pearson’s r = 0.03; n.s.). Conclusions Our communication course measurably improved communication skills, especially for female students. These improvements did not depend predominantly on an extension of the interview time. Obviously, “technical” aspects of communication can be taught better than “emotional” communication skills.

Background. The influence of patient characteristics on family practitioners' (FPs') diagnostic decision making has mainly been investigated using indirect methods such as vignettes or questionnaires. Direct observation-borrowed from social and cultural anthropology-may be an alternative method for describing FPs' real-life behavior and may help in gaining insight into how FPs diagnose respiratory tract infections, which are frequent in primary care. Objective. To clarify FPs' diagnostic processes when treating patients suffering from symptoms of respiratory tract infection. Methods. This direct observation study was performed in 30 family practices using a checklist for patient complaints, history taking, physical examination, and diagnoses. The influence of patients' symptoms and complaints on the FPs' physical examination and diagnosis was calculated by logistic regression analyses. Dummy variables based on combinations of symptoms and complaints were constructed and tested against saturated (full) and backward regression models. Results. In total, 273 patients (median age 37 years, 51% women) were included. The median number of symptoms described was 4 per patient, and most information was provided at the patients' own initiative. Multiple logistic regression analysis showed a strong association between patients' complaints and the physical examination. Frequent diagnoses were upper respiratory tract infection (URTI)/common cold (43%), bronchitis (26%), sinusitis (12%), and tonsillitis (11%). There were no significant statistical differences between "simple heuristic'' models and saturated regression models in the diagnoses of bronchitis, sinusitis, and tonsillitis, indicating that simple heuristics are probably used by the FPs, whereas "URTI/common cold'' was better explained by the full model. Conclusion. FPs tended to make their diagnosis based on a few patient symptoms and a limited physical examination. Simple heuristic models were almost as powerful in explaining most diagnoses as saturated models. Direct observation allowed for the study of decision making under real conditions, yielding both quantitative data and "qualitative'' information about the FPs' performance. It is important for investigators to be aware of the specific disadvantages of the method (e. g., a possible observer effect).

Background: The high rate of antibiotic prescriptions general practitioners (GPs) make for respiratory tract infections (RTI) are often explained by non-medical reasons e.g. an effort to meet patient expectations. Additionally, it is known that GPs to some extent believe in the necessity of antibiotic treatment in patients with assumed bacterial infections and therefore attempt to distinguish between viral and bacterial infections by history taking and physical examination. The influence of patient complaints and physical examination findings on GPs' prescribing behaviour was mostly investigated by indirect methods such as questionnaires.Methods: Direct, structured observation during a winter "cough an cold period" in 30 (single handed) general practices. All 273 patients with symptoms of RTI (age above 14, median 37 years, 51% female) were included. Results: The most frequent diagnoses were 'uncomplicated upper RTI/common cold' (43%) followed by 'bronchitis' (26%). On average, 1.8 (95%-confidence interval (CI): 1.72.0) medicines per patient were prescribed (cough-and-cold preparations in 88% of the patients, antibiotics in 49%). Medical predictors of antibiotic prescribing were pathological findings in physical examination such as coated tonsils (odds ratio (OR) 15.4, 95%-CI: 3.666.2) and unspecific symptoms like fatigue (OR 3.1, 95%-CI 1.46.7), fever (OR 2.2, 95%-CI: 1.14.5) and yellow sputum (OR 2.1, 95%-CI: 1.14.1). Analysed predictors explained 70% of the variance of antibiotic prescribing (R2 = 0,696). Efforts to reduce antibiotic prescribing, e.g. recommendations for self-medication, counselling on home remedies or delayed antibiotic prescribing were rare.

Background: It is generally unknown which clinical skills students acquire during medical education and which factors influence their levels of competence. Methods: We asked German medical students how competent they felt in performing individual clinical skills. Results: Third year students evaluated their competence in clinical skills, on average, not better than 4.7 on a Likert scale ranging from 1 ('excellent') to 6 ('insufficient'). The average score for fifth year students was 4.1, for final-year students 3.3. Deficits in all groups of students were most prominent in communication skills and diagnostic skills. Conclusions: These results are a plea for a structured curriculum including training courses to practice clinical skills.

Real-life comparative data of implantable cardioverter-defibrillator (ICD) longevity are needed to identify the best possible device longevity for optimal patient comfort and to minimize risk for multiple replacements. We retrospectively studied ICD longevity in a large single-center population. At our institution, 1272 consecutive patients were implanted with 1665 ICD or cardiac resynchronization therapy with defibrillator (CRT-D) devices between 1998 and 2010. Device data and follow-up were retrieved from the continuous ICD clinic documentation, and generator replacements were verified from the hospital charts. Kaplan-Meier event probabilities for the time to generator replacement were calculated according to device type, pacing percentage (sum of atrial, right and left ventricular pacing, if applicable) and right ventricular pacing threshold, incidence of ICD shocks, and manufacturer. Multivariate Cox proportional hazards regression was performed in addition. A total of 470 devices were replaced for elective replacement indicator. These occurred after 5.4 years (95 % confidence interval, 5.1 to 5.6 years) in 175 of 625 implanted Boston Scientific or Guidant devices, after 5.7 years (5.5 to 5.9 years) in 266 of 883 Medtronic devices, and 5.2 years (5.0 to 5.4 years) in 29 of 157 Biotronik devices, respectively. Differences between manufacturers remained significant upon multivariate analysis (Medtronic vs. Boston Scientific: P = 0.01; both vs. Biotronik: P < 0.01) as did differences of device type (single- and dual-chamber ICD vs. CRT-D, P < 0.01) and pacing percentage (P < 0.01). Pacing output and ICD shocks did not influence battery longevity. ICD longevity differed significantly between manufacturers, independent of device type or pacing parameters.

Objectives Neonates and infants are at the highest risk of developing perioperative hypothermia. A number of methods to prevent hypothermia during pediatric anesthesia are in use, and despite the fact that conventional forced-air warmers are the most effective devices, they are not always sufficient enough to maintain body temperature. Therefore, recently a new forced-air warming system with an increased warm air flow was introduced to the market. Aim The aim of this study was to evaluate this new forced-air warming system in neonates and infants during pediatric anesthesia. We hypothesized that the new blanket alone is sufficient enough to prevent neonates and infants from intraoperative hypothermia. Methods Neonates and infants (body weight <10kg) were enrolled in this prospective multicenter observational study. After admission to the operating room, the children were placed on the new forced-air warming blanket. Body temperature was measured continuously until admission to the recovery room or pediatric intensive care unit (PICU). Results Hundred and nineteen children with a median body weight of 4.1kg (range: 0.79.8) were enrolled and received their intended treatment. Median body temperature at the induction of anesthesia was 36.5 degrees C (range: 35.338.2 degrees C) and increased with the length of the operation up to 37.8 degrees C (37.138.2 degrees C) after 180min. Median body temperature after admission to the recovery room or PICU was 37.2 degrees C (36.038.6 degrees C) and remained significantly above baseline (P<0.05). Conclusions The new forced-air warming system as a sole warming device is effective in preventing perioperative hypothermia during pediatric anesthesia in neonates and infants.

OBJECTIVE: The aim of this study was to analyse the psychometric properties of the short version of the Calgary Cambridge Guides and to decide whether it can be recommended for use in the assessment of communications skills in young undergraduate medical students. METHODS: Using a translated version of the Guide, 30 members from the Department of General Practice rated 5 videotaped encounters between students and simulated patients twice. Item analysis should detect possible floor and/or ceiling effects. The construct validity was investigated using exploratory factor analysis. Intra-rater reliability was measured in an interval of 3 months, inter-rater reliability was assessed by the intraclass correlation coefficient. RESULTS: The score distribution of the items showed no ceiling or floor effects. Four of the five factors extracted from the factor analysis represented important constructs of doctor-patient communication The ratings for the first and second round of assessing the videos correlated at 0.75 (p<0.0001). Intraclass correlation coefficients for each item ranged were moderate and ranged from 0.05 to 0.57. CONCLUSIONS: Reasonable score distributions of most items without ceiling or floor effects as well as a good test-retest reliability and construct validity recommend the C-CG as an instrument for assessing communication skills in undergraduate medical students. Some deficiencies in inter-rater reliability are a clear indication that raters need a thorough instruction before using the C-CG.

Introduction: We evaluated the effectiveness and safety profile of the tyrosine kinase inhibitor sunitinib in patients with advanced or metastatic renal cell carcinoma (a/mRCC) in a real-world setting. Methods: We analyzed data of adult a/mRCC patients treated with sunitinib. Data were derived from the German non-interventional post-approval multicenter STAR-TOR registry (NCT00700258). Progression-free survival (PFS), overall survival (OS), and adverse events (AEs) were evaluated using descriptive statistics and survival analyses for the entire cohort and patient subgroups. Results: A total of 116 study sites recruited 702 patients treated with sunitinib (73.1% male; median age 68.0 years; median Karnofsky index 90%) between November 2010 and May 2020. The most frequent histological subtype was clear cell RCC (81.6%). Sunitinib was administered as first-line treatment in 83.5%, as second line in 11.7%, and as third line or beyond in 4.8% of the patients. Drug-related AEs and serious AEs were reported in 66.3% and 13.9% of the patients, respectively (most common AE: gastrointestinal disorders; 39.7% of all patients). Conclusions: This study adds further real-world evidence of the persisting relevance of sunitinib for patients with a/mRCC who cannot receive or tolerate immune checkpoint inhibitors. The study population includes a high proportion of patients with unfavorable MSKCC poor-risk score, but shows still good PFS and OS results, while the drug demonstrates a favorable safety profile. The STAR-TOR registry is also registered in the database of US library of medicine (NCT00700258).

Stress is a constant characteristic of everyday life in our society, playing a role in triggering several chronic disorders. Therefore, there is an ongoing need to develop new methods in order to manage stress reactions. The regulatory function of right medial-prefrontal cortex (mPFC) is frequently reported by imaging studies during psychosocial stress situations. Here, we examined the effects of inhibitory and excitatory preconditioning stimulation via cathodal and anodal transcranial direct current stimulation (tDCS) on psychosocial stress related behavioral indicators and physiological factors, including the cortisol level in the saliva and changes in brain perfusion. Twenty minutes real or sham tDCS was applied over the right mPFC of healthy subjects before the performance of the Trier Social Stress Test (TSST). Regional cerebral blood flow (rCBF) was measured during stimulation and after TSST, using pseudo-continuous arterial spin labeling (pCASL). Comparing the effect of the different stimulation conditions, during anodal stimulation we found higher rCBF in the right mPFC, compared to the sham and in the right amygdala, superior PFC compared to the cathodal condition. Salivary cortisol levels showed a decrease in the anodal and increase in cathodal groups after completion of the TSST. The behavioral stress indicators indicated the increase of stress level, however, did not show any significant differences among groups. In this study we provide the first insights into the neuronal mechanisms mediating psychosocial stress responses by prefrontal tDCS. (C) 2013 Wiley Periodicals, Inc.