Visual evoked potentials (VEPs) were recorded in a group of 20 operators aged 25-45 years during two sessions, before and after a 5-hour work at computer terminals, in order to assess visual system fatigue. The outcomes were referred to the norms established for the age-matched population of 30 subjects not exposed to professional contact with computers. Most of the examined operators suffered various complaints concerning not only the organ of vision but the central nervous system as well. VEPs were elicited by means of monocular stimulation using the reversal checkerboard pattern and recorded simultaneously from the scalp electrodes placed over the right and the left cerebral hemisphere. Only recording acquired after finishing of a working day demonstrated significant statistically abnormalities of the VEPs waveforms, which suggests their transient character. The changes mentioned above included prolongation of peaks P100 and N2 latency with concomitant attenuation of their amplitudes and a decrease of the correlation coefficient values for the recordings from the hemispheres. The preliminary findings presented in this paper seem to justify a conclusion that the non-invasive VEPs method can be considered as the objective indicator of the central visual fatigue induced by the workload at computer terminals.

Accommodation, Ocular↗

PubMedDate not supplied

[Heart potential mapping].

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Action Potentials↗

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[New trends in electrocardiology].

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Congresses as Topic↗

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[Localization of infarction of the anterior and inferior myocardial wall by body surface mapping].

11 patients after anterior myocardial infarction and 7 patients inferior myocardial infarction were subjected to potentials mapping from 87 body surface electrode system. The reference group was made up by 15 healthy individuals. The analysis referred to isopotential and isointegral maps during the 20 ms and 40 ms of the QRS onset and for the entire QRS. It was stated that the occurrence of abnormal potential minimum might be the essential diagnostic criterion. In the case of anterior infarction, the abnormal negative potentials is located in the vicinity of the sternum, whereas in inferior infarction in right and lower part of the chest. The diagnostics of inferior infarction requires additional criteria, ventricular activation time maps especially.

Action Potentials↗

PubMedDate not supplied

Meningioma with the unique coexistence of secretory and lipomatous components: a case report with immunohistochemical and ultrastructural study.

Meningiomas exhibit a broad spectrum of differentiation potency corresponding to different histological subtypes. The separate secretory or lipomatous transformation of meningothelial cells is uncommonly encountered in meningiomas classified into distinct secretory or lipomatous variants. The coexistence of these two different histological subtypes is extremely rare. We report an exceptional case of secretory meningioma associated with extensive lipomatous component in a 58-year-old woman. CT scan and MRI of the brain showed a well-defined tumor mass in the right temporal lobe with areas of adipose tissue and extensive surrounding brain edema. Microscopically, the tumor was composed of two components: whorls of meningothelial cells with numerous PAS-positive hyaline inclusions (pseudopsammoma bodies) and numerous mature adipocyte-like cells. The presence of neutral fat was confirmed by oil-red-O staining. The hyaline inclusions and tumor cells surrounding them showed strong immunoreactivity for EMA and CEA. Ultrastructural findings confirmed both secretory and lipomatous differentiation of tumor cells. The majority of lipidized neoplastic cells shared the features of meningothelial cells and adipocytes. Our result supports the opinion that lipomatous component ought to be considered as an advanced lipidization of neoplastic meningothelial cells rather than true metaplastic transformation of meningothelial cells into mature fat tissue. The present case of meningioma demonstrates a unique coexistence of secretory and lipomatous meningothelial components, reflecting the multipotency of phenotypic transformation of primary meningothelial cells.

Female↗