Free recall and recognition of semantic material--a gerontopsychologic study of a two-phase model of reproduction

Based on a sample of N = 145 subjects, 57 to 96 years of age, the generation-recognition model of recall (12) was investigated. Using standardized word lists, a differential effect of the word frequency on free recall and recognition is shown. The assumption of separate processes in free recall is thus confirmed. The difference score from recognition and recall is shown to be age-independent and difficult to interpret as retrieval score in the framework of other performance measures.     

Establishment of ionic channels and signalling cascades in the embryonic stem cell-derived primitive endoderm and cardiovascular system

The first organ system to be established in early embryogenesis is the cardiovascular system which develops upon interaction with hypoblastic cells of the primitive endoderm. Here we focus on recent work on embryoid bodies derived from pluripotent embryonic stem (ES) cells. Ca(2+) oscillations and Ca(2+) signalling pathways during the differentiation of primitive endodermal cell layers are reported. Furthermore, the development-dependent expression of ion channels and the buildup of signalling cascades involved in the modulation of voltage-dependent L-type Ca(2+) channels during early cardiomyogenesis and the formation of functional vascular structures in the process of vasculogenesis and angiogenesis are reviewed. We also report on the use of green fluorescent protein reporter gene expression under the control of cardiac-specific promoters, e.g. the human cardiac alpha-actin promoter, which enables the identification and in vivo characterization of cardiomyocytes at very early stages of cardiomyogenesis.     

Localisation of myocardial ischaemia from the magnetocardiogram using current density reconstruction method: computer simulation study

A computer simulation study is performed to investigate the method of current density reconstruction to localise myocardial ischaemia. A computer model of the entire human heart is used to simulate the excitation and repolarisation process in eight topographically different cases of myocardial ischaemia. The associated magnetocardiogram is calculated at 37 positions of the KRENIKON^* biomagnetic measurement equipment. The method of current density reconstruction is applied at the S-point (the last discemible deviation from the ST-segment at the end of the QRS-complex) of the MCG to find characteristics of the myocardial ischaemia simulated by the model. The results show that it is possible to determine the location of the ischaemia. The current density distribution may be interpreted physiologically in terms of the so-called ‘injury current’. This indicates that magnetocardiography might be a suitable method for noninvasive ischaemia diagnosis, and further investigations of the current density reconstruction method for the injury current should be performed on patients with ischaemic heart disease.     

Mathematical analysis of arterial enhancement and optimization of bolus geometry for CT angiography using the discrete fourier transform.

PURPOSE: The goal of this work was to develop a clinically applicable mathematical algorithm to analyze and optimize individual arterial enhancement in CT angiography (CTA). METHOD: Assuming a time-invariant linear system, the discrete Fourier transform was used to calculate the transfer function of the system ("patient function") from the arterial time-attenuation response to a test bolus. The patient function was subsequently used to predict aortic enhancement in five select patients and to calculate optimized biphasic injection protocols in two of these patients undergoing CTA of the abdominal aorta. RESULTS: Arterial time-attenuation curves were accurately predicted in all patients. Optimized biphasic contrast agent injection protocols resulted in uniform aortic enhancement at the predefined level over the entire scanning period in both subjects despite markedly different contrast agent volumes and injection rates used. CONCLUSION: Fourier analysis of the time-attenuation response to a test bolus is a simple and feasible approach to optimize arterial enhancement in CTA.     

Über den Einfluss des Lactoflavins auf die Gewebsatmung von Gehirn und Netzhaut

Ohne Zusammenfassung     

Computed tomographic angiography: historical perspective and new state-of-the-art using multi detector-row helical computed tomography

Since its clinical introduction in 1991, volumetric computed tomography scanning using spiral or helical scanners has resulted in a revolution for diagnostic imaging. In addition to new applications for computed tomography, such as computed tomographic angiography and the assessment of patients with renal colic, many routine applications such as the detection of lung and liver lesions have substantially improved. Helical computed tomographic technology has improved over the past eight years with faster gantry rotation, more powerful X-ray tubes, and improved interpolation algorithms, but the greatest advance has been the recent introduction of multi detector-row computed tomography scanners. These scanners provide similar scan quality at a speed gain of 3-6 times greater than single detector-row computed tomography scanners. This has a profound impact on the performance of computed tomography angiography, resulting in greater anatomic coverage, lower iodinated contrast doses, and higher spatial resolution scans than single detector-row systems.