An aphasia database on the internet: a model for computer-assisted analysis in aphasiology.

A web-based software model was developed as an example for data mining in aphasiology. It is used for educating medical and engineering students. It is based upon a database of 254 aphasic patients which contains the diagnosis of the aphasia type, profiles of an aphasia test battery (Aachen Aphasia Test), and some further clinical information. In addition, the cerebral lesion profiles of 147 of these cases were standardized by transferring the coordinates of the lesions to a 3D reference brain based upon the ACPC coordinate system. Two artificial neural networks were used to perform a classification of the aphasia type. First, a coarse classification was achieved by using an assessment of spontaneous speech of the patient which produced correct results in 87% of the test cases. Data analysis tools were used to select four features of the 30 available test features to yield a more accurate diagnosis. This classifier produced correct results in 92% of the test cases. The neural network approach is similar to grouping performed in group studies, while the nearest-neighbor method shows a design more similar to case studies. It finds the neurolinguistic and the lesion data of patients whose AAT profiles are most similar to the user's input. This way lesion profiles can be compared to each other interindividually. The Aphasia Diagnoser is available on the Web address http://fuzzy.iau.dtu.dk/aphasia.nsf and thus should facilitate a discussion about the reliability and possibilities of data-mining techniques in aphasiology.

Comparison of tissue impedance measurements with nerve fiber architecture in human telencephalon: value in identification of intact subcortical structures.

OBJECT: After establishing the general possibility of real-time impedance monitoring during stereotactic procedures in five postmortem human brains, the authors proceeded to analyze the value of impedance measurements in intact cerebral structures. METHODS: The authors performed impedance measurements at 24 selected points in the brain of a human cadaver and labeled the points by using 1,1'-dilinoleyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiI). The texture of the nerve fibers was visualized using confocal laser scanning microscopy, which allowed classification of distinct anatomical regions in the white and gray matter according to their fiber structure (density, direction, structure, and diameter). These regions displayed characteristic differences in impedances according to their fiber structure at frequencies between 8000 and 10,000 Hz. Differences in tissue impedance are not removed, although they are shifted to higher values by fixation with formalin. The reference frequency used in clinical environments (50,000 Hz) is not useful for distinct localization purposes. Finally, the orientation of the electrode in relation to the tissue is a crucial factor. CONCLUSIONS: It should be possible to draw conclusions about the correct position of the stereotactic needle on the basis of the proposed location, the texture of the fibers (orientation and density), and the orientation of the electrode.

[Sensory innervation of the hip joint capsule in dogs]. / Die sensible Innervation der Capsula articularis coxae beim Hund.

The innervation of the canine hip joint has become increasingly important in the treatment of hip dysplasia and hip arthrosis, since investigations proved that simple removal of periosteum around attachment of hip joint capsule, called denervation results in an instant analgesia and allows the dog to regain joyful freedom of movement. A macroscopic-anatomic examination of 16 canine hips furnished new findings and knowledge in the field of veterinary medicine on the sensitive innervation of the canine hip joint capsule. Accordingly, the craniolateral area of hip joint capsule is innervated by rami articulares of N. glutaeus cranialis, the caudolateral area by rami articulares of N. ischiadicus and the medial area by rami articulares of N. femoralis.

Comparison of brain ribonucleases of rabbit, guinea pig, rat, mouse and gerbil.

The brain ribonucleases of rabbit, guinea pig, rat, mouse and gerbil were investigated by histochemical and biochemical methods. For the localization, the ribonucleases were electrophoretically transferred from cryostat sections to polyacrylamide gels. Elevated ribonuclease activities were found in the cortex, the basal ganglia, the hippocampal formation and the ventricles, whereas the corpus callosum and the internal capsule exhibited lower activities. The total RNA degrading activities of the brain extracts of the different species varied in a wide range. However, a pre-requisite for the measurement of acid soluble degradation products in the test system was the inactivation of endogeneous ribonuclease inhibitors, present in all extracts. Molecular weight analysis by means of SDS-polyacrylamide gel electrophoresis revealed a characteristic set of ribonucleases for each species, consisting of enzymes with different pH-optima.

Diameter of axons and thickness of myelin sheaths of the pyramidal tract fibres in the adult human medullary pyramid.

After perfusion fixation with a mixture of paraformaldehyde, glutaraldehyde, and potassium-chromate 4 adult human medullary pyramids were examined with the electron microscope. The myelin sheaths showed only mild signs of post mortal destructions. The periodicity of the lamellae is preserved and varies about 17 nm. For quantitative purposes specimens were taken at random from regions with an extend of half a mm2 on the cross section of the pyramid. On the average 62 lamellae (s = 5, n = 200) built up 1 micron myelin sheath in the 4 brains. The myelin sheath thickness and the inner circumference of the myelin sheath are measured. The axon diameter is calculated from the inner circumference. We obtained an average number of 66,000 fibres, s = 11,000 per mm2. Fibres with a total diameter below 4 microns amount to 87.9%, fibres from 4 to 10 microns to 10.77%, and larger than 10 microns to 1.4%. An axon diameter of about 0.5 micron combined with a thickness of the myelin sheath of 0.3 micron was most often found in all 4 cases. The fibres showed a broad variation of myelin thickness. In a given group of the small axons the thickest myelin sheath exceeded 3 to 4 times the value of the thinnest one. The coefficient of correlation between axon diameter and myelin sheath thickness was calculated as r2 = 0.56. No correspondence exists between frequency maxima and the ratio g, axon diameter to total diameter. Below a total fibre diameter of 5 microns the ratio g scatters broadly about 0.6, fibres larger than 5 microns exceed the value of 0.6. From the morphological data only large sized fibres can evoke a strong effect on compound action potentials if the method of reconstruction of the action potential from fibre size frequency distribution is employed.

Stereographic reconstruction of human brain CT series.

A relatively simple method for the three-dimensional reconstruction of brain contours from a series of CT scans is presented. A procedure is described for storing the structural information obtained from the CT series and for organizing and displaying the data. Furthermore, it is shown how additional features such as standardized artery information taken from an atlas can be superimposed on the spatially reconstructed brain model. It is proposed that three-dimensional representations in the form of computed stereo pairs are quite suitable for morphological documentation of specific neuropsychological issues, such as the localization of aphasic syndromes.

Ultrastructure of reticulum cells in the bone marrow.

In this study the attempt was made to classify the reticulum cells of the bone marrow on the basis of electron-microscopic findings. The basis of the differentiation was the ability of the cells to phagocytize substances or not. For two cell types the intracytoplasmic filaments were used as distinctive marks. The following classification resulted: (a) phagocytic reticulum cells, (b) undifferentiated reticulum cells, (c) fibrous reticulum cells of type I, which contain filaments of 4-8 nm diameter and are located near the blood sinus of the bone marrow, (d) fibrous reticulum cells of type II, which contain intracytoplasmic filaments of 10 nm diameter; since these cells contain neutral fat bodies, the possibility of a reversible conversion to fat cells has to be assumed and (e) fibroblasts, cells which synthesize the substance of the extracellular space. A connection of reticulum cells to haematopoietic functions or to stem cell functions could be found.

[Ultrastructure of erythroid cells in a case of congenital dyserythropoietic anaemia type II (author's transl)]. / Ultrastruktur der erythroiden Zellen bei einer kongenitalen dyserythropoetischen Anämie Typ II.

The ultrastructure of erythroblasts in a case of congenital dyserythropoietic anaemia type II with a negative serum-lysis test is described. The well known symptoms in electronmicroscopy in CDA type I and II are faced to our findings. Morphological changes of hypolemmal cisterns are described and their possible meaning is discussed.