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Biomedical subjects

F Post

Publications and source records attributed to F Post.

At least 19 recordsLinked to original sources

[Pathogenesis and therapy of the acute coronary syndrome: differentiated advantage of glycoprotein IIb/IIIa receptor antagonists for high-risk patients].

Pathogenesis and therapy of the acute coronary syndrome: differentiated advantage of glycoprotein IIb/IIIa receptor antagonists for high-risk patients Activated thrombocytes and their aggregation into a thrombus play a decisive role in the pathogenesis of the acute coronary syndrome. Glycoprotein (GP) IIb/IIIa receptor antagonists block the binding of fibrinogen to GP IIb/IIIa receptors of activated thrombocytes and inhibit their aggregation. Patients with an acute coronary syndrome and raised troponin levels who are to undergo primary coronary revascularization profit particularly from treatment with GPIIb/IIIa receptor antagonists. This is especially so if they also have diabetes.

Angioplasty, Balloon, Coronary↗

[Acute coronary syndrome (without ST-elevation)].

Antithrombotic therapy in acute coronary syndrome without ST-segment elevation should be initiated with aspirin 100 mg/day (loading dose 250-500 mg) and Clopidogrel 75 mg/day (loading dose 300 mg). In addition, anticoagulation with unfractionated heparin or low molecular weight heparin should be started. A GP IIb/IIIa receptor blocker can be given either upfront (Eptifibatide/Tirofiban) or directly in the cathlab preceding PCI (Abciximab). Aspirin should be given in the chronic phase lifelong, Clopidogrel for at least nine months. An invasive strategy is recommended in high-risk patients within 48 hours.

Acute Disease↗

[Brain-natriuretic-peptide (BNP) for improvement of the diagnostic determination in a conserving emergency room].

BACKGROUND: Dyspnea is one of the most common symptoms for presentation in an emergency department. Evaluation of this very unspecific symptom can be very time-consuming and costly. Thus, we investigated the value of a rapid bedside-test for BNP in discriminating dyspnea due to "cardiac" reasons from "non-cardiac" dyspnea in the emergency room. METHODS AND RESULTS: We studied 100 patients who presented to the emergency department with "severe dyspnoea" as the leading symptom. In all patients BNP was determined from blood samples drawn on admission. All patients had to complete a dyspnea score for severity of dyspnea. The treating physician was blinded to the results of BNP measurements. After discharge patients were divided into "cardiac" and "non-cardiac" dyspnea on the basis of all findings gathered during the hospital stay by a panel of 3 physicians blinded to the results of BNP measurements. The 2 groups were compared for difference in BNP levels and for differences in the dyspnea score. While the dyspnea score showed no significant difference, there was a significant difference in BNP measurements (p < 0.0001). CONCLUSIONS: With the TRIAGE BNP test a rapid discrimination between dyspnea due to ventricular failure and "non-cardiac" dyspnea can be obtained within 20 minutes after first presentation. This test can save time and resources in this critical group of patients.

Aged↗

Comparison of image compression viability for lossy and lossless JPEG and Wavelet data reduction in coronary angiography.

BACKGROUND: Lossless or lossy compression of coronary angiogram data can reduce the enormous amounts of data generated by coronary angiographic imaging. The recent International Study of Angiographic Data Compression (ISAC) assessed the clinical viability of lossy Joint Photographic Expert Group (JPEG) compression but was unable to resolve two related questions: (A) the performance of lossless modes of compression in coronary angiography and (B) the performance of newer lossy wavelet algorithms. This present study seeks to supply some of this information. METHODS: The performance of several lossless image compression methods was measured in the same set of images as used in the ISAC study. For the assessment of the relative image quality of lossy JPEG and wavelet compression, the observers ranked the perceived image quality of computer-generated coronary angiograms compressed with wavelet compression relative to the same images with JPEG compression. This ranking allowed the matching of compression ratios for wavelet compression with the clinically viable compression ratios for the JPEG method as obtained in the ISAC study. RESULTS: The best lossless compression scheme (LOCO-I) offered a mean compression ratio (CR) of 3.80:1. The quality of images compressed with the lossy wavelet-based method at CR = 10:1 and 20:1 was comparable to JPEG compression at CR = 6:1 and 10:1, respectively. CONCLUSION: The study has shown that lossless compression can exceed the CR of 2:1 usually quoted. For lossy compression, the range of clinically viable compression ratios can probably be extended by 50 to 100% when applying wavelet compression algorithms as compared to JPEG compression. These results can motivate a larger clinical study.

Algorithms↗

Comparison of diagnostic performance of cardiac troponin I on the IMMULITE system with other automated troponin I assays in minor myocardial damage.

An analytical and clinical evaluation of cardiac troponin I (cTnI) on the IMMULITE system is presented. The assay results were compared with those of the Stratus II and the Dimension RxL-HM. A between-run imprecision CV < 20% was found at a cTnI concentration of 0.23 microg/L (functional limit of detection). On the basis of a reference study including 215 patients without ischemic heart disease (97.5th percentile: 0.294 microg/L) and 36 patients clinically classified as having stable angina pectoris (<0.22 microg/L) a preliminary cutoff level of 0.3 microg/L was defined. Assay linearity, sample stability, influence of sample material and method comparison studies were performed. In patients with Duchenne's disease, chronic hemodialysis treatment, pulmonary embolism, coronary artery bypass surgery and minimally cardiac surgery the cTnI results of the IMMULITE agreed better with the Dimension RxL-HM than with the Stratus II data. Of 142 samples from patients with unstable angina 67 samples were classified as cTnI positive with the IMMULITE, 76 with the Dimension RxL-HM, and 62 with the Stratus II. In conclusion, the new assay is sensitive for the determination of cTnI and easy to perform within 45 min.

Adult↗

A review of technical advances in virtual colonoscopy.

Early detection of polyps has proven to lead to a decrease in incidence of colon cancer. In the past few years, virtual colonoscopy has been developed as a patient-friendly screen-ing technique. The procedure comprises the following steps. First, the patient's colon is cleansed and transanally inflated with air. Subsequently, a 3D image volume is acquired of the abdomen by CT or MRI. Finally, the bowel surface is extracted and visualized, after which the physician virtually navigates through the colon and examines the surface for abnormalities. This paper describes the progress in research for virtual colonoscopy.

Colonography, Computed Tomographic↗

Analytical and clinical evaluation of troponin I determination on dimension RXL-HM.

The evaluation of cardiac troponin I (cTnI) on the Dimension RxL-HM analyzer is presented. The one-step enzyme immunoassay is based on two cTnI specific monoclonal antibodies. Performed on a separate module of the analyzer, assay-time is 17 minutes. Using as criterion a between-run impression CV <20% the functional limit of detection was set at 0.1 microg/l. Cutoff level for minor myocardial damage of 0.1 microg/l was found. In Duchenne's dystrophy, patients showed increased cardiac Troponin T (cTnT) but no increased cTnI. In patients with a history of coronary heart disease undergoing chronic hemodialysis, cTnT and cTnI were increased. In different patients with submassive pulmonary embolism, increased cTnI was determined. In coronary artery bypass surgery without perioperative myocardial infarction, patients with extracorporeal circulation showed significantly higher cTnI at 24 h after surgery than those with minimal cardiac surgery. In patients with unstable angina, increased cTnI was found more often than on Stratus analyzer. In conclusion, the new assay is a very sensitive cTnI assay, fast and easy to perform in parallel to enzyme and substrate assays.

Adult↗

A new thrombectomy catheter device (AngioJet) for the disruption of thrombi: An in vitro study.

In this study we examined a new thrombectomy catheter device. Different kinds of in vitro generated thrombi and cadaver thrombi were disrupted in test tubes. The mean disruption rate (and disruption time for 1 g of thrombus) was 225 +/- 65 mg/sec (5 +/- 2 sec) for whole-blood, 117 +/- 60 mg/sec (12 +/- 9 sec) for fibrin, 41 +/- 18 mg/sec (30 +/- 18 sec) for mixed, 70 +/- 42 mg/sec (17 +/- 5 sec) for unorganized, 45 +/- 8 mg/sec (22 +/- 4 sec) for partly, and 5 +/- 1 mg/sec (216 +/- 29 sec) for completely organized cadaver thrombi (P < 0.05). More than 99% of fragmented particles of whole-blood thrombi were 0-12 microm in diameter. The particle size of fibrin, mixed, and cadaver thrombi was similar, with 25%-40% of particles between 0-12 microm, 55%-71% >12-24 microm, and 2%-7% >24 microm. The device may be effectively used in the therapy of massive pulmonary embolism or acute peripheral and coronary artery syndromes when medical thrombolysis is contraindicated and organization of thrombus is absent. Further studies need to be performed to investigate the potential effects of particle microembolization. Cathet. Cardiovasc. Intervent. 47:381-389, 1999.

Cadaver↗

Verbal creativity, depression and alcoholism. An investigation of one hundred American and British writers.

BACKGROUND: An earlier study of 291 world famous men had shown that only visual artists and creative writers were characterised, in comparison with the general population, by a much higher prevalence of pathological personality traits and alcoholism. Depressive disorders, but not any other psychiatric conditions, had afflicted writers almost twice as often as men with other high creative achievements. The present investigation was undertaken to confirm these findings in a larger and more comprehensive series of writers, and to discover causal factors for confirmed high prevalences of affective conditions and alcoholism in writers. METHOD: Data were collected from post-mortem biographies and, where applicable, translated into DSM diagnoses. The frequencies of various abnormalities and deviations were compared between poets, prose fiction writers, and playwrights. RESULTS: A high prevalence in writers of affective conditions and of alcoholism was confirmed. That of bipolar affective psychoses exceeded population norms in poets, who in spite of this had a lower prevalence of all kinds of affective disorders, of alcoholism, of personality deviations, and related to this, of psychosexual and marital problems, than prose fiction and play writers. CONCLUSIONS: A hypothesis is developed, which links the greater frequency of affective illnesses and alcoholism in playwrights and prose writers, in comparison with poets, to differences in the nature and intensity of their emotional imagination. This hypothesis could be tested by clinical psychologists collaborating with experts in literature on random samples of different kinds of writers.

Alcoholism↗

The transition from inhomogeneous to homogeneous kinetics in CO binding to myoglobin.

Heme proteins react inhomogeneously with ligands at cryogenic temperatures and homogeneously at room temperature. We have identified and characterized a transition from inhomogeneous to homogeneous behavior at intermediate temperatures in the time dependence of CO binding to horse myoglobin. The turnover is attributed to a functionally important tertiary protein relaxation process during which the barrier increases dynamically. This is verified by a combination of theory and multipulse measurements. A likely biological significance of this effect is in the autocatalysis of the ligand release process.

Animals↗

Creativity and psychopathology. A study of 291 world-famous men.

BACKGROUND: This investigation sought to determine the prevalences of various psychopathologies in outstandingly creative individuals, and to test a hypothesis that the high prevalence of mental abnormalities reported in prominent living creative persons would not be found in those who had achieved and retained world status. METHOD: The family background, physical health, personality, psychosexuality and mental health of 291 famous men in science, thought, politics, and art were investigated. The membership of the six series of scientists and inventors, thinkers and scholars, statesmen and national leaders, painters and sculptors, composers, and of novelists and playwrights was determined by the availability of sufficiently adequate biographies. Extracted data were transformed into diagnoses in accordance with DSM-III-R criteria, when appropriate. RESULTS: All excelled not only by virtue of their abilities and originality, but also of their drive, perseverance, industry, and meticulousness. With a few exceptions, these men were emotionally warm, with a gift for friendship and sociability. Most had unusual personality characteristics and, in addition, minor 'neurotic' abnormalities were probably more common than in the general population. Severe personality deviations were unduly frequent only in the case of visual artists and writers. Functional psychoses were probably less frequent than psychiatric epidemiology would suggest, and they were entirely restricted to the affective varieties. Among other functional disorders, only depressive conditions, alcoholism, and, less reliably, psychosexual problems were more prevalent than expected in some professional categories, but strikingly so in writers. CONCLUSIONS: Similar findings have been reported for living artists and writers, and this suggests that certain pathological personality characteristics, as well as tendencies towards depression and alcoholism, are causally linked to some kinds of valuable creativity.

Creativity↗

Structural relaxation and nonexponential kinetics of CO-binding to horse myoglobin. Multiple flash photolysis experiments.

The geminate recombination kinetics of CO-myoglobin strongly deviates from single exponential behavior in contrast to what is expected for unimolecular reactions (1). At low temperatures, this result was attributed to slowly exchanging conformational states which differ substantially in barrier height for ligand binding. Above 160 K the kinetics apparently slow down with temperature increase. Agmon and Hopfield (2) explain this result in terms of structural relaxation perpendicular to the reaction coordinate, which enhances the activation energy. In their model, structural relaxation homogenizes the kinetic response. Recently, Steinbach et al. (3) proposed a relaxation model which conserves the kinetic inhomogeneity. Below we test these conjectures by single and multiple excitation experiments. This method allows for discrimination between parallel (inhomogeneous) and sequential (homogeneous) kinetic schemes. The kinetic anomaly above 160 K is shown to result from a homogeneous, structurally relaxed intermediate. However a second anomaly is found above 210 K concerning the inhomogeneous phase which may indicate either a shift in activation energy or entropy.

Animals↗

Solvent damping of internal processes in myoglobin studied by specific heat spectroscopy and flash photolysis.

We address the question of dynamic coupling between protein and solvent by comparing the enthalpy relaxation of the solvent (75% v/v glycerol-water) to internal ligand binding in myoglobin. When the solvent relaxation is slow compared to intramolecular events we observe decoupling of protein motions from the solvent. In the opposite limit there is a significant contribution of the solvent to internal friction. The solvent enhances the apparent activation energy of transitions in myoglobin. This result is discussed in terms of a generalized Kramer's law involving a dynamic friction coefficient.

Animals↗

Bipolar affective disorder in old age.

In a retrospective study of 67 elderly bipolar patients the first manic attack occurred at about age 60, often after a long period from the time of the first affective episode, after which further depressive episodes occurred. This calls into question Perris' criteria for unipolar diagnosis. Among the men, a preponderance of cerebral-organic disorders was found. The evidence for sub-classification of bipolar disorders into secondary or symptomatic manias is discussed. The recurrent nature of the illness in old age stresses the need for further evaluation of lithium prophylaxis.

Age Factors↗