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Biomedical subjects

M R Fischer

Publications and source records attributed to M R Fischer.

11 recordsLinked to original sources
PubMed2003

[57-year-old patient with diplopia and headache].

A 57-year old patient presented with an 8 week history of headache and diplopia. Left-sided incomplete oculomotor nerve paresis was found, whereas further clinically relevant visual impairment was not seen. Magnetic resonance imaging of the head showed an extensive intra-, para- and suprasellar tumor which in combination with a markedly elevated serum prolactin level was identified as a macroprolactinoma. The symptoms began 7 years ago with a loss of libido and virility. The application of a dopamine agonist lead to a reduction of serum prolactin level to 0.5% of the initial value and a considerable tumor regression within three months. The development of oculomotor nerve paresis is an unusual manifestation of prolactinoma. By contrast, long-term medical history with slowly developing signs and symptoms of hypogonadotropic hypogonadism are often to be found in men. The delayed diagnosis is responsible for the high percentage of macroprolactinomas in male subjects.

Diagnosis, Differential↗
PubMed2001

Comparing health care delivery systems--initiating a student exchange project between Europe and the United States.

BACKGROUND: Cross-cultural contact among different health care systems can provide a framework for identifying the strengths and weaknesses of one's own healthcare system. However, such contact has rarely had much impact upon medical education curricula. Despite intense debate on reforming the healthcare delivery systems (HCDS) in Europe and the United States, there is very little formal representation of this interdisciplinary field in our educational programs. DESCRIPTION: To address this problem, a medical student exchange program was conducted in which students developed case studies that produced comparative analyses of HCDS in Germany, Sweden, Denmark and the United States. Each case is intended to highlight critical differences among the systems. EVALUATION: Students and their faculty preceptors completed pre- and post-exchange questionnaires to assess perceived knowledge of the HCDS and the adequacy of time devoted to it in their curricula. Both perceived that too little attention was devoted to this content in their programs. Following the exchange, students described clear increases in perceived knowledge. DISCUSSION: Our common interest in curriculum reform was key to implementing the exchange. The written cases generated by the students are being developed as course material in some of the schools and a conference is planned to disseminate the cases and the implementation strategies for their inclusion in medical curricula.

Cross-Cultural Comparison↗
PubMed2000

[Computer-assisted instruction in medicine: a multicenter evaluation study in 7 German language media resource centers].

EVA, a multicentre study of seven computer resource centres (CRCs) in three German-speaking nations, was carried out over a period of six months to gather structural and process data regarding the use of computer-based instruction (CBI) applications in medicine, and to identify the factors contributing to a more successful integration of CBI into the medical curriculum. 618 machine-readable questionnaires from CRC users and seven questionnaires on structural data of the participating CRCs covering 51 computer stations were evaluated. For Macintosh workstations (n = 34), an additional digital log-protocol was analysed. In conclusion, it seems that so far less than 10% of medical students use CBI programs in German-speaking countries. The data show the presently still poor integration of CBI into the medical curriculum.

Computer-Assisted Instruction↗
PubMed1997

[Immunogenic hyperthyroidism with hyperdynamic heart failure and early cirrhotic transformation of the liver].

HISTORY AND CLINICAL FINDINGS: A 58-year-old woman was admitted because of jaundice, ascites and marked oedema. For three years she had suffered from nervousness, decreasing fitness and weight loss, which had been assumed as due to chronic alcoholism. Liver biopsy revealed extensive fibrosis, in part with early cirrhotic transformation. This was followed by cardiac failure with atrial fibrillation (ventricular rate 140/min) and marked pleural effusions. The thyroid was diffusely enlarged and there were signs of exophthalmos. INVESTIGATIONS: Bilirubin concentration was 3 mg/dl, lactate dehydrogenase activity was 310 U/l, cholesterase 1.3 kU/l and the prothrombin test was 21%. The TSH level was 0.01 microU/ml while the free thyroxine level was 4.7 ng/dl and that of free triiodothyronine 13.5 pg/ml. Chest radiograph revealed cardiomegaly, bilateral peripheral pulmonary congestion and pleural effusions to midfield. Right heart catheterization excluded pulmonary hypertension; cardiac output was 10l/min. The thyroid was enlarged on ultrasound and diffusely echopoor, as in immune thyroid disease. TREATMENT AND COURSE: Cardiac failure regressed and thyroid function normalized within ten days on propranolol, 4 x 40 mg and thiamazole 3 x 40 mg daily intravenously. Subtotal thyroidectomy was performed three weeks later with subsequent thyroid hormone substitution. Liver functions were normal six months later and ultrasound showed no signs of cirrhotic change and the ascites had resolved. CONCLUSION: Hyperthyroidism is frequently associated with changes in liver functions. In extreme cases, high-output cardiac failure may occur, with liver congestion and clinical as well as histological changes like those in liver cirrhosis.

Adrenergic beta-Antagonists↗
PubMed1996

[CASUS model trial. A computer-assisted author system for problem-oriented learning in medicine].

The CASUS-project, a three year publicly funded effort to improve the quality of continuing medical education in Germany, has one major goal: The development and evaluation of an easy-to-handle author-system for problem-oriented learning in medicine. On the theoretical basis of the cognitive apprenticeship-approach, the concept of a teaching and learning database as a hypermedia system was built. The student should learn to manage authentical problems in the form of authentical clinical cases. The step-by-step learning process is expert-guided by the clinical authors of each case. The creation of various differential diagnoses by the learner is strongly supported in the process. The structure of the program can also be used for case-based examinations. In parallel to the technical development, a case-selection process for medical students students in internal medicine was initiated. About 120 relevant diseases were identified to be represented in the CASUS-case library. Prevalence, transferability of knowledge, treatability, urgence of treatment and preventive aspects were used as selection criteria. The system will be evaluated during the implementation of test cases and will then be available to be used by authors and students on a routine basis in 1997.

Authorship↗
PubMed1994

Data quality in computerized patient records. Analysis of a haematology biopsy report database.

This paper addresses the problem of data quality in electronic patient records using a computerized haematology biopsy report system as an example. Physicians extracted five parameters from a traditional free text cytology report and encoded these parameters thus producing a computer processable report. The parameters were 1) the organ biopsied, 2) quality of specimen, 3) cytological diagnosis including 4) a modifier code for the main diagnosis code (i.e. status post chemotherapy, Y-code) and 5) an additional key describing the degree of remission obtained after chemotherapy of acute leukemias. From the various steps involved in generating the electronic record we selected two critical ones: encoding of free text terms by physician staff; entering of the coded terms into a computer by lab staff. We analyzed the rates of correct, incorrect and missing codes for each of the five parameters. Our findings indicate that in this model of an electronic patient record: 1) there is significant inaccuracy of physicians during the process of encoding the free text report with error rates between 3.2 and 28% and omission rates up to 64%. 2) lab staff entering these coded data into the computer introduce additional errors (0-7.8%) but rarely miss correctly encoded data (0-0.9%). 3) introducing a revised coding system data quality improved significantly (p < or = 0.001) with a fivefold increase of correct and a 75% reduction of missing codes. 4) the clinical relevance of the diagnoses encoded as perceived by clinicians is a significant factor affecting error and omission rates.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

13C magic angle spinning NMR study of the light-induced and temperature-dependent changes in Rhodobacter sphaeroides R26 reaction centers enriched in [4'-13C]tyrosine.

Solid-state 13C magic angle spinning (MAS) NMR has been used to investigate detergent-solubilized photosynthetic reaction centers of Rhodobacter sphaeroides R26, selectively enriched in [4-13C]-tyrosine. The reaction centers were frozen, in the dark and while subject to intense illumination, and studied at temperatures between approximately 215 and approximately 260 K. The signal consists of at least seven narrow lines superimposed on a broad doublet. The chemical shift anisotropy is similar to that for crystalline tyrosine. The two narrowest resonances, corresponding to signals from individual tyrosines, are 28 +/- 5 Hz wide, comparable to what is observed for quaternary carbons in linearly elastic organic solids. The line width as well as the chemical shift of these signals is essentially independent of temperature. This provides strong evidence for an unusually ordered, well-shielded, and structurally, electrostatically, and thermodynamically stable interior of the protein complex without structural heterogeneities. As the temperature is lowered, additional signal from the labels develops and the natural abundance resonances from the detergent broaden, providing evidence for considerable flexibility at the exterior of the protein complex and in the detergent belt at the higher temperatures. In addition, the NMR provides evidence for an electrostatically uniform and neutral complex, since the total dispersion in isotropic shifts for the labels is < 5 ppm and corresponds to electron density variations of less than 0.03 electronic equivalents with respect to tyrosine in the solid state or in solution. When the sample is frozen while subject to intense illumination, a substantial part of the protein is brought into the charge-separated state P.+QA.-. At least three sharp resonances, including the narrowest lines, are substantially reduced in intensity. It is argued that this effect is caused by the electronic spin density associated with the oxidized primary donor P.+. These results strongly suggest that the environment of the special pair is extremely rigid and question the role of protein conformational distortions during the primary photoprocess.

Carbon Isotopes↗
PubMed1989

Phentolamine blocks presynaptic serotonin autoreceptors in rabbit and rat brain cortex.

Possible antagonist effects of phentolamine at presynaptic serotonin autoreceptors were studied in slices of the occipito-parietal cortices of the rabbit and the rat. The slices were preincubated with 3H-serotonin and then superfused and stimulated electrically with single pulses or pulse trains. Nitroquipazine 1 mumol/l, a compound that inhibits the high affinity neuronal uptake of serotonin, was present in the superfusion medium in all one pulse-experiments as well as in experiments in which the effect of unlabelled serotonin was examined. In rabbit cortical slices, unlabelled serotonin reduced the single pulse-evoked overflow of tritium. Its concentration-response curve was not changed by the selective alpha 2-adrenoceptor antagonist idazoxan 1 mumol/l but was shifted to the right by phentolamine 1 and 10 mumol/l. Phentolamine 10 mumol/l also shifted to the right the concentration-inhibition curve of the selective 5-HT1-receptor agonist 5-carboxamidotryptamine. When the slices were stimulated by trains of 30 pulses at 3 Hz, phentolamine 1 and 10 mumol/l but not 0.1 mumol/l increased the evoked overflow of tritium, the maximal increase amounting to 178%; its effect was enhanced in the presence of nitroquipazine 1 mumol/l plus idazoxan 10 mumol/l (a drug combination that, when given alone, slightly increased the evoked overflow of tritium). The serotonin receptor antagonist metitepin at concentrations of 0.01-1 mumol/l also increased the overflow of tritium elicited by 30 pulses/3 Hz, the maximal increase amounting to 280%; its effect was potentiated in the presence of nitroquipazine 1 mumol/l plus idazoxan 10 mumol/l but was abolished or almost abolished in the presence of nitroquipazine 1 mumol/l plus phentolamine 10 mumol/l (a drug combination that, given alone, greatly increased the evoked overflow of tritium). When slices were stimulated by trains of 360 pulses at 3 Hz, there was no apparent antagonism of phentolamine 10 mumol/l against the inhibitory effect of unlabelled serotonin. In rat brain cortex slices, unlabelled serotonin reduced the overflow of tritium elicited by 4 pulses delivered at 100 Hz. Again, phentolamine 10 mumol/l shifted the concentration-response curve to the right. It is concluded that phentolamine blocks presynaptic serotonin autoreceptors in rabbit and rat brain cortex with pA2 values of 6.44 and 5.95, respectively. Previous failures to detect the antagonistic effect against exogenous agonists were probably due to stimulation conditions that led to marked endogenous autoinhibition of serotonin release.(ABSTRACT TRUNCATED AT 400 WORDS)

Adrenergic alpha-Antagonists↗
PubMedDate not supplied

Do computers teach better? A media comparison study for case-based teaching in radiology.

A prospective study was performed to better define the role of computers in teaching radiology to medical students. Two hundred twenty-five 3rd-year students were randomly assigned to one of four groups and exposed to 10 radiology cases as well as to a voluntary weekly radiology lecture. Group A used computer-based cases with interactive elements; group B used computer-based cases without interactive elements; group C used paper-based cases with interactive elements; and group D was not exposed to the cases and served as a control group. On a multiple-choice question test, groups A, B, and C showed significant improvement (+11.2%, +15.1%, and +13.0%, respectively), whereas group D did not (+0.6%). On an image interpretation test, group A showed the most improvement (+15.7% [P <.001]), followed by group B (+15.1% [P <.01]) and group C (+10.2% [P <.05]); group D showed no significant improvement (+8.5%). No significant differences in the learning outcome were found between the two interactive groups (computer based and paper based). Computer-based teaching with case studies (with or without interactivity) improves students' problem-solving ability in radiology.

Chi-Square Distribution↗
PubMedDate not supplied

Building a cytology report database: a computer-assisted system for documentation, evaluation and hospital-wide recall of haematological biopsy reports.

Owing to an increasing number of biopsies from different organ systems in our institution and referring institutions there was need to develop a computer-based system to improve documentation, analysis and reports of pathological findings, as well as speed of transmission of information in a clinical haematology/oncology unit. As terminals connected to a central minicomputer are located on all wards of our hospital, we have now provided a faster way of moving information from the cytology reporting site to all hospital departments. Using the hospital's minicomputer we developed an easy-to-use system based on five different codes for each cytological specimen: organ biopsied, quality of specimen, cytological diagnosis including information as to status of patient (i.e. pretherapy), and an additional code describing the degree of remission obtained after chemotherapy of acute leukemias. After microscopic analysis of the specimen these five codes are read into a terminal; minutes after the diagnosis is made, a short version of the report can be accessed from all wards in the hospital.

Biopsy↗