Search PubMed⌕ Search

Biomedical subjects

O Aaserud

Publications and source records attributed to O Aaserud.

8 recordsLinked to original sources
PubMed1992

Regional cerebral blood flow after long-term exposure to carbon disulfide.

Sixteen former rayon viscose workers were investigated four years after the exposure to carbon disulfide was discontinued. Median age was 58 years (range 43-65 years), median exposure time was 17 years (range 10-35 years). Encephalopathy was diagnosed in altogether 14 workers. To further explore pathophysiological mechanisms, cerebrovascular investigations were employed. Doppler ultrasound examination of the precerebral vessels in 15 workers showed a slight stenosis of the left internal carotid artery in one. Regional cerebral blood flow investigation (rCBF) with single photon emission computerized tomography (SPECT) with Xenon-133 gas was performed in 14. There was no significant difference from a control group. Regional side-to-side asymmetries beyond reference limits were demonstrated in eight workers. The abnormalities were modest, but may indicate a tendency toward focal blood flow disturbances in workers with long-term exposure to carbon disulfide.

Adult↗
PubMed1991

Brain damage caused by hydrogen sulfide: a follow-up study of six patients.

Hydrogen sulfide (H2S) poisoning involves a risk of hypoxic brain damage. Six patients who lost consciousness due to H2S poisoning are described. The symptoms varied from anosmia in the patient with the shortest but highest exposure to delayed neurological deterioration in the patient with the longest exposure. The two patients with the most serious symptoms developed pulmonary edema, which may have prolonged the hypoxia. The patients were reexaminated 5 years or more after the poisoning. The five patients who had been unconscious in H2S atmosphere for from 5 to 15-20 min showed persisting impairment at neurological and neuropsychological re-examination. Memory and motor function were most affected. One patient was seriously demented. Recent reports of large groups of H2S-poisoned workers probably underestimate the risk of sequelae, due to the inclusion of cases with exposure of short duration and lack of follow-up.

Adult↗
PubMed1990

Carbon disulfide exposure and neurotoxic sequelae among viscose rayon workers.

In Norway's only viscose rayon plant, carbon disulfide (CS2) concentrations in ambient air usually were between 30 and 50 mg/m3 during the first 23 years of production. From 1970/1971 until the factory was closed in 1982, corresponding values were 10-25 mg/m3. Through all of these years, high peak exposures of CS2 and H2S occurred. In 1986, 16 of the 24 men still at work in 1982 and with at least 10 years' experience in the spinning room agreed to participate in this study. Clinical neurological examination demonstrated abnormalities in 15; neuropsychological tests showed impairments of probable organic origin in 14. Thirteen had cerebral atrophy demonstrated by cerebral computed tomography (CT). Electromyography (EMG) was abnormal in six, neurography in 11. Regional cerebral blood flow measurements indicated flow asymmetries in eight, whereas Doppler investigation of the extracranial carotid and vertebral arteries, electroencephalography (EEG), and evoked response investigations were mostly normal. Based on these results and the exposure data, a diagnosis of CS2-induced encephalopathy was reached in eight workers; another six had an encephalopathy in which CS2 exposure was regarded as a partial cause. Correspondingly, seven had a neuropathy probably caused by CS2 exposure alone; in three others, CS2 was found to be the partial cause of a neuropathy. This indicates that long-term, relatively moderate exposure to CS2 in association with high peak exposures to CS2 and H2S involves a substantial risk of developing neurotoxic disease.

Adult↗
PubMed1990

Vibration sensitivity thresholds: methodological considerations.

Vibration sensitivity thresholds were studied in 12 healthy volunteers using 25, 50, 100 and 250 s-1 stimulus frequencies from an instrument with automated and manual modes ('Vibra Mk II'). For the automated mode, a forced choice principle was adopted. All measurements were performed from both the knuckle of the IInd metacarpophalangeal joint and the medial malleolus on four successive days. In addition, a conventional tuning fork method for vibration sensitivity was applied. The results show high interindividual and intraindividual variation in all measurements. The threshold values measured by the automated system were significantly lower than those by manual system at all frequencies. The largest variation was seen at 250 s-1 and the most uniform values at 100 s-1. There was a clear difference between the values from knuckle and medial malleolus, the values in the foot being lower. There was no learning effect. Clear age-related increase in vibration thresholds was observed. Conventional tuning fork-method showed clear differences in vibration sensitivity between hand and foot, in accordance with computer assisted method. The higher sensitivity of the automated method compared to the manual makes this the method of choice, although further investigations to finish the method and to build up a broader reference material is desirable.

Adult↗
PubMed1989

[H2S poisoning and nervous system damage].

H2S (hydrogen sulfide) is a very toxic gas. Even brief exposure to high concentrations may be fatal. Unconsciousness may occur without warning. Those who try to help are often poisoned too. In Norway, most poisonings have been described in connection with the herring oil and fish meal industry, farmers handling manure, and sewage work. The risk of hypoxic damage to the nervous system is considerable. The clinical picture varies, and the connection between the patients' symptoms and the poisoning is easily overlooked, especially with delayed sequelae, which may occur several weeks after the acute poisoning. The risk of damage depends on both the exposure time and the concentration of H2S, and a thorough anamnesis, noting the course of events, is important in order to achieve a correct diagnosis.

Adult↗
PubMed1988

Neurological examination, computerized tomography, cerebral blood flow and neuropsychological examination in workers with long-term exposure to carbon disulfide.

Sixteen males, formerly exposed to carbon disulfide (CS2) for at least 10 years (mean 20 years), were administered a neurological examination, cerebral computerized tomography (CT), regional cerebral blood flow (rCBF) examination and neuropsychological examination. The clinical neurological examination revealed abnormalities in 15; cerebral CT showed signs of atrophy in 13; and neuropsychological examination indicated brain organic changes in 13. With the rCBF examination, slight abnormalities were found in 8. The findings indicate that long-term exposure to CS2 involves a risk of developing toxic encephalopathy, demonstrable on both neurological and neuropsychological examination. Furthermore, structural changes in the brain may be demonstrable by cerebral CT.

Brain↗
PubMed1985

Functional cervical myelography with iohexol.

Thirty patients underwent functional cervical myelography, i.e. radiographs in the lateral view were obtained in extension as well as in flexion of the neck. Sagittal tomography was performed in both positions. Widening of the subarachnoid space and decreased sagittal diameter of the spinal cord due to shortening were demonstrated in the lateral view in flexion. In some cases with advanced narrowing or spinal block in extension, such widening in flexion resulted in better diagnostic images by providing passage of the contrast medium caudally. Although iohexol (Omnipaque, Nyegaard & Co., Oslo) was regularly forced into the posterior cranial fossa by the movements, the frequency of side effects was approximately the same as in our former trials with iohexol in conventional cervical myelography. EEG changes occurred in two patients (7%). A sitting position for 3-4 min after the examination followed by an elevated head end of the bed was probably important for preventing side effects from the contrast medium. Specific questioning revealed twice as many subjective side effects as reported after general questions alone.

Adult↗