Two Weeks Inhalation Exposure to 4-terf-Butyltoluene Causes Persistent Changes in Visually Evoked Potentials in Rats

Abstract: The effects of repeated exposure to 20 p.p.m. 4-tert-butyltoIuene (CAS No. [98-51-1]) 6 hr/day for 14 days on the function of the intact nervous system were examined by measurements of flash evoked potentials in Wistar rats. The exposure to 4-tert-butyltoluene induced changes in the amplitudes of the flash evoked potentials. The changes were significantly different from controls on day 2, 19 and 26 after cessation of the exposure, but not on day 5 and 12. No significant difference in body weight gain between groups was found during the experiment. These results indicate that repeated exposure to 20 p.p.m. 4-tert-butyltoluene causes persistent changes in the function of the central nervous system measured as changes in the flash evoked potential. A reevaluation of the present TLV-value of 10 p.p.m. for 4-tert-butyltoluene is suggested.     

Clinical and histopathological findings of ''psoriatic neurodermatitis'' and of typical lichen simplex chronicus

BACKGROUND: We have seen several patients with itchy lichenified plaques located bilaterally on the elbows and/or knees and have named this condition 'psoriatic neurodermatitis' (PN). OBJECTIVE: The purpose of this study was to compare clinical and histopathological characteristics of these patients to those of patients with typical lichen simplex chronicus (LSC). METHODS: Nineteen patients with PN and 34 patients with typical LSC were included. Besides clinical dermatological evaluation, the prick test was carried out on 49 patients; the Phadiatop test on 40 patients; the patch test with European standard series on 47 patients; histopathological evaluation on 39 patients; and clinical psychiatric examination on 38 patients. RESULTS: Almost exclusively, PN was seen in females and was located on the extremities. It caused more plaques than typical LSC did. In PN, the plaques were smaller, sharper, more keratotic and less excoriated, and had fewer lichenoid papules around them. Itching was usually more severe in the evening, while resting and in a hot environment in typical LSC, but not in PN. In plaques of PN, microabscesses in the horny layer, hypogranulosis, regular acanthosis and thinning of the suprapapillary plates were more frequent, and hyperpigmentation in the basal layer was less. In patients with PN, depressive disorder was found more frequently; and generalized anxiety disorder or psychosomatic characteristics, less. There were no significant differences in the results of prick, Phadiatop and patch tests between patients with PN and those with typical LSC. CONCLUSION: In our opinion, it is most likely that the so-called PN is itchy psoriasis superimposed by LSC.     

Report on a conference on organic solvents and the nervous system.

At two scientific conferences in 1985, one in Copenhagen sponsored by the Nordic Council of Ministers and the World Health Organization (WHO), the other in Raleigh, NC, it was concluded that chronic toxic encephalopathy may develop following long-term occupational exposure to organic solvents (1,2). The terms organic affective syndrome, mild and severe chronic toxic encephalopathy were suggested for this condition describing increasing severity. In May 1990, a conference on organic solvents and the nervous system was held in Copenhagen sponsored by the Commission of the European Communities and the Danish Ministry of the Environment (3). Scientists and representatives from the governments, industries, and labour organisations from the EEC and US participated.     

Contraction-specific differences in maximal muscle power during stretch-shortening cycle movements in elderly males and females

Elderly people (age 75 years; n=48 males and 34 females) were studied in order to elucidate gender differences in elderly subjects on the determinants of muscle power (force and velocity) during a stretch-shortening cycle. All subjects performed three maximal counter-movement vertical jumps using both legs, on a force platform (Kistler 9281 B). The eccentric (Ep) and concentric (Cp) phases of the jumps were analyzed. The Ep was further divided into an acceleration phase (Ep_acc: from the start of the downward movement to the maximal negative velocity) and deceleration phase (Ep_dec: from the maximal negative velocity to the end of the downward movement). Jump height for the men was higher than for the women (P < 0.001). During both Ep_acc and Ep_dec no significant differences were observed between males and females in force and power generation. However, the men had a higher peak muscle power during the Cp, which may be explained exclusively by the velocity determinant (P < 0.001). No specific gender-related strategy appeared to influence the motor pattern of the movement. The comparable eccentric force generation of the leg extensors in both genders suggests a similar ability to cope with eccentric muscle actions during everyday activities. In contrast, the marked lower capacity for concentric contractions in women may result in an impaired performance, especially in activities where intense and rapid movements are essential, for example when reversing a forward fall. This may be one reason why elderly women are more prone to falls than are elderly men. Accepted: 19 September 2000     

Demonstration of T Lymphocytes in Cerebrospinal Fluid

Cerebrospinal fluid (CSF) was allowed to drop straight into Hanks's balanced salt solution. After centrifugation the pellet was resuspended and mixed with sheep erythrocytes. The mixture was further handled as in the E-rosette test with peripheral blood lymphocytes. CSF from 20 individuals were investigated, and rosette-forming cells (RFC) were found in all. Six patients with normal fluid had between 46% and 83% RFC. Four patients with multiple sclerosis had increased numbers of RFC (94%-96%). Low numbers of RFC were found in one patient with cerebellar ataxia and in one of two patients with acute viral meningitis. With this technique RFC can be counted even in normal CSF with a 3-ml sample.