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Biomedical subjects

E Myrseth

Publications and source records attributed to E Myrseth.

5 recordsLinked to original sources

Effects of water temperature on performance: a practical evaluation of a neutral buoyancy facility.

Manual and cognitive performance of two female and four male divers was evaluated in "cold" and "warm" water in a Neutral Buoyancy Facility (NBF). A test battery of six manual and cognitive tests was applied in a fixed sequence in three separate, 3-h dives: Dive 1) Water temp.: 18-19 degrees C, wet suit 3-5 mm thick; Dive 2) Water temp.: 32-33 degrees C bathing suit and T-shirt; and Dive 3) Water temp.: 18-19 degrees C, tailor made wet suit 6.5 mm thick. No significant differences in performance between the three conditions were recorded. Mean rectal temperatures decreased by 1 degree C in all dive conditions, except in females in Dive 2. Ventilation was significantly higher in Dive 1 than in Dives 2 and 3. Thermal discomfort was reported only after 2 h in Dive 1. We suggest that support divers may work safely, comfortably and effectively for at least 2 h in water of 18-19 degrees C, if dressed in thermal protective wet suits.

Adult

Pulmonary mechanical function and diffusion capacity after deep saturation dives.

To assess the effects of deep saturation dives on pulmonary function, static and dynamic lung volumes, transfer factor for carbon monoxide (T1CO), delta-N2, and closing volume (CV) were measured before and after eight saturation dives to pressures of 3.1-4.6 MPa. The atmospheres were helium-oxygen mixtures with partial pressures of oxygen of 40-60 kPa. The durations of the dives were 14-30 days. Mean rate of decompression was 10.5-13.5 kPa/hour. A total of 43 divers were examined, six of whom took part in two dives, the others in one only. Dynamic lung volumes did not change significantly but total lung capacity (TLC) increased significantly by 4.3% and residual volume (RV) by 14.8% (p less than 0.05). CV was increased by 16.7% (p less than 0.01). The T1CO was reduced from 13.0 +/- 1.6 to 11.8 +/- 1.7 mmol/min/kPa (p less than 0.01) when corrected to a haemoglobin concentration of 146 g/l. Effective alveolar volume was unchanged. The increase in TLC and decrease in T1CO were correlated (r = -0.574, p less than 0.02). A control examination of 38 of the divers four to six weeks after the dives showed a partial normalisation of the changes. The increase in TLC, RV, and CV, and the decrease in T1CO, could be explained by a loss of pulmonary elastic tissue caused by inflammatory reactions induced by oxygen toxicity or venous gas emboli.

Adult

Giant cell glioblastoma: a work-up of 2 cases with long survival.

Two patients, in whom visual disturbance (Case 1) and sudden hemiparalysis due to a hemorrhagic lesion (Case 2) had led to craniotomy and histological diagnosis of giant cell glioblastoma, each had an unexpectedly long survival period of 7 and 9 years, respectively. Radiologically, the tumours were well demarcated, but without any distinguishing features, by comparison with glioblastomas in general. The tumours, to a great extent, consisted of cells with large, bizarre multiple nuclei. The highly pleomorphic cells displayed strong cytoplasmic GFAP immunopositivity, which suggested an astroglial origin. Thus, these tumours were considered a variant of glioblastoma ("giant cell glioblastoma") with a more favourable prognosis than experienced by most patients with glioblastoma.

Adult

Glioblastoma associated with multiple sclerosis: coincidence or induction?

A 63-year-old man died of a brain tumor 29 years after onset of multiple sclerosis (MS). The MS diagnosis was based upon clinical evidence of two brain stem lesions, separate in time, retinal periphlebitis, a fluctuating course of the disease, and supported by the observation of definite cognitive impairment at the age of 41 years, and an increased number of lymphocytes in the cerebrospinal fluid which normalized during gradual recovery. The MS diagnosis was confirmed at autopsy, which also revealed a glioblastoma developing adjacent to typical MS plaques.

Brain

Elevated concentrations of glutamate and aspartate in human ventricular cerebrospinal fluid (vCSF) during episodes of increased CSF pressure and clinical signs of impaired brain circulation.

In the ventricular cerebrospinal fluid (vCSF) of 10 hydrocephalic patients the mean (+/- S.D.) concentrations of glutamate and asparate were 2.9 +/- 0.2 and 0.2 +/- 0.2 microM, respectively. Significantly higher concentrations of these amino acids were found in two patients (glutamate 37.8 and 22.4 microM, aspartate 2.2 and 0.6 microM) with symptoms of impaired brain tissue perfusion, i.e. relative ischemia due to severely increased intraventricular CSF pressure. Our results are consistent with recent experiments in rats showing increased extracellular concentrations of glutamate and aspartate during transient cerebral ischemia.

Adult