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Biomedical subjects

W Friauf

Publications and source records attributed to W Friauf.

7 recordsLinked to original sources
PubMed1997

Phase III randomized trial of surgery with or without intraoperative photodynamic therapy and postoperative immunochemotherapy for malignant pleural mesothelioma.

BACKGROUND: Patients with malignant pleural mesothelioma (MPM) usually die of progressive local disease. This report describes the results of a Phase III trial comparing maximum debulking surgery and postoperative cisplatin, interferon alpha-2b, and tamoxifen (CIT) immunochemotherapy with and without intraoperative photodynamic therapy (PDT) to determine (1) whether such a multimodal approach can be performed with minimum morbidity and mortality in malignant pleural mesothelioma (MPM), and (2) whether first-generation (i.e., 630-nm laser light, Photofrin II) intrapleural PDT impacts on local recurrence of survival. METHODS: From July 1993 to June 1996, 63 patients with localized MPM were randomized to either PDT or no PDT. The tumors of 15 patients could not be debulked to 5 mm. Patients assigned to PDT (n = 25) and no PDT (n = 23) were similar with respect to age, sex, tumor volume, and histology. RESULTS: The type of resection (11 pleurectomies and 14 pneumonectomies vs. 12 pleurectomies and 11 pneumonectomies), length postoperative stay, and ICU time were comparable (PDT vs. no PDT). There was one operative death (hemorrhage), and each group had two bronchopleural fistulas. Postoperative staging divided patients into the following categories: stage I: PDT, 2, no PDT, 2; stage II: PDT, 2, no PDT, 2; stage III, PDT, 21; no PDT, 17; stage IV, PDT, 0; no PDT, 2. Comparable numbers of CIT cycles were delivered. Median survival for the 15 non-debulked patients was 7.2 months, compared to 14 months for the 48 patients on protocol. There were no differences in median survival (14.4 vs. 14.1 months) or median progression-free time (8.5 vs. 7.7 months), and sites of first recurrence were similar. CONCLUSIONS: Aggressive multimodal therapy can be delivered for patients with higher stage MPM. First-generation PDT does not prolong survival or increase local control for MPM.

Adult↗
PubMed1990

A theoretical calculation of the electric field induced by magnetic stimulation of a peripheral nerve.

A mathematical model is presented that predicts the electric field induced in the arm during magnetic stimulation of a peripheral nerve. The arm is represented as a homogeneous, cylindrical volume conductor. The electric field arises from two sources: the time-varying magnetic field and the accumulation of charge on the arm surface. In magnetic stimulation both of these contributions are significant. The magnitude of the electric field is greatest near the surface of the arm, and is well localized. Various coil orientations are examined; the smallest electric fields are induced when the coil is perpendicular to the arm surface, the largest when the coil is parallel. These results are consistent with many experimental observations in the literature, and aid in the basic understanding of magnetic stimulation of the peripheral nervous system.

Arm↗
PubMed1990

Effects of coil design on delivery of focal magnetic stimulation. Technical considerations.

The localization of effects from magnetic coil stimulation is not immediately obvious. We measured the magnetic fields produced by several different coils and compared the results with theoretical calculations. Magnetic stimuli were delivered from a Cadwell MES-10 magnetic stimulator using 3 circular coils (one 9 cm in diameter; two with an angulated extension, 5 and 9 cm in diameter) and twin oval coils arranged in a butterfly shape (each coil approximately 4 cm in diameter) and from a Novametrix Magstim 200 using two circular flat-spiral coils (6.7 and 14 cm in diameter). Peak-induced strength of the magnetic field was recorded with a measuring loop (1 cm in diameter) at different distances from the center of the coil. When the measuring loop was moved in the same plane laterally from the center of the coil, for all coils except the butterfly-shaped coil, the field was highest in the center and fell off near the circumference of the coil. The field dropped progressively when measurements were made more distant from the plane of the coils. The electric field induced from the magnetic coil could be calculated from the coil geometry. For all coils except the butterfly-shaped coil, the largest electric field was at the circumference of the coils. The 6.7 cm flat-spiral coil induced currents similar to those induced by the larger coils but more focally. The butterfly-shaped coil induced the largest currents under its center, where the circumferences of the two component coils come together. The component of the electric field parallel to the wire in the center of this coil was the largest and most localized.

Electric Stimulation↗
PubMed1989

Subdural electrode as a dipole source for magnetoencephalography.

A subdural electrode was designed and constructed with 3 pairs of contacts to make 3 dipoles. The dipoles well approximate the expected magnetic behavior for a current dipole and can be used clinically to test localization capabilities of magnetoencephalography.

Electrodes↗
PubMed1987

Localization of magnetic interictal discharges in temporal lobe epilepsy.

Three young adults with intractable complex partial seizures were studied by electroencephalography, magnetoencephalography, and electrocorticography. Interictal electroencephalographic (EEG) spikes for each patient were grouped according to their morphological characteristics and distribution across channels. Mapping of simultaneously recorded magnetoencephalographic signals produced dipolar patterns from which the three-dimensional locations of equivalent current dipoles were calculated, whereas the mapping of EEG spikes showed single regions of electronegativity. The magnetic spikes were localized to the anterotemporal lobe, and the EEG spikes were localized somewhat anterior or posterior to the magnetic spikes. The magnetoencephalographic findings corresponded well with intraoperative electrocorticographic and depth-electrode findings of discharging areas located over the lateral temporal lobe and on the basal and mesial surfaces of the temporal cortex.

Adult↗