SUMMARY1. The concentration of total protein in c.s.f. and plasma has been measured in fetal sheep of different gestational ages and in the adult. In c.s.f. it was highest (approximately 840 mg/100 ml.) in the youngest fetuses (35 days) and declined steeply by 60 days (260 mg/tOO ml.). It decreased less markedly in the last half of gestation to reach about 50 mg/100 ml. at 125 days which is twice the adult value. Protein concentration in plasma was lowest in the youngest fetuses and did not rise much until the second half of gestation during which time it doubled. There was a further rather larger increase between the late fetal (125 days) stage and the adult.2. Albumin, fetuin, a-fetoprotein (AFP), transferrin and lipoprotein were identified in c.s.f. and plasma.3. The concentrations of albumin, AFP and fetuin in c.s.f. and plasma at different gestational ages were measured using immunodiffusion and radioimmuno-assays.4. Albumin was the major protein in plasma at all ages studied (35-128 days gestation and adult). Its concentration increased throughout gestation whereas that of fetuin was similar at all fetal ages and that of AFP declined markedly during the second half of gestation. In the adult, fetuin was only about 0.1 % of the total protein in plasma and AFP was not detectable.5. In 35-40 day fetuses albumin, AFP and fetuin accounted for 90 % of the total protein concentration in plasma and for about 70-80 % of the total protein concentration of c.s.f. As gestation progressed the concentration of all three proteins in c.s.f. declined. But the concentration of AFP and fetuin fell more rapidly and to a greater extent than that of albumin; neither AFP nor fetuin could be detected in adult c.s.f.6. The c.s.f.: plasma ratio was above 50 % for AFP and above 60 % for fetuin at 35 days compared with about 25 % for albumin at the same fetal age. The c.s.f.: plasma ratios for all three proteins declined with increasing fetal age and were not significantly different from each other by about mid gestation.

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A cross-sectional study of 85 long-term solvent exposed seamen working on chemical tankers compared to 59 unexposed seamen. Symptoms from the nervous system, clinical neurological findings and neurographic measurements were studied. The examinations were performed at least 2 weeks after the last solvent exposure. A stepwise multiple regression analysis was used to evaluate the dose-response relationship between the registered data on one hand and solvent exposure, employment on chemical tankers, age, alcohol and chloroquine phosphate consumption on the other. A significant correlation was found between increasing solvent exposure and reduced sensory nerve conduction velocities, as well as between increasing solvent exposure and prolonged distal latencies of motor nerves, and between increasing exposure and reduction of action potential amplitudes of sensory nerves. No correlation was found between solvent exposure and symptoms from the nervous system or clinical neurological findings.

With an indirect agglutination technique using rabbit antisera to human immunoglobulins, IgG antibodies to rabbit erythrocytes were detected in 211 of 221 unconcentrated cerebrospinal fluids from patients with diseases of the nervous system and controls. The titres varied from 0.25 to 128. The highest titre in the control group was 4, the geometric mean 1.5. The titres were highest in the groups with elevated total protein, for instance inflammatory diseases with mean titre of 9.25. The titre divided by total protein concentration did not vary much in the different groups, but tended to be higher than controls in multiple sclerosis, inflammatory diseases and vascular brain lesions, and lower in the other groups. It did not increase parallel to IgG in multiple sclerosis and inflammatory diseases.

In the CSFs from 13 out of 30 phenytoin-treated patients the IgG concentrations were lower than the lowest among 20 controls, while only 3 out of 37 patients with brain lesions without epilepsy had so low IgG value. Titers of IgG antibodies to rabbit erythrocytes were similar in the three groups. It should be kept in mind, when evaluating results of IgG determinations in clinical neurology, that reduced IgG may be a consequence of phenytoin treatment. Reduced IgG concentrations without reduction of an antibody belonging to the IgG class indicate that the suppression of immunoglobulin synthesis by phenytoin may be selective.

Rabbits treated with phenytoin in various ways, were immunized with human serum or with sheep erythrocytes. The antibody response in rabbits injected with the antigen mixed with phenytoin differed distinctly from the response obtained in animals having received the antigen alone or mixed with diluent. The effect of phenytoin on the antibody response depended on the nature of the antigen. The response to some antigens was suppressed, to some potentiated, and to some potentiated in the early phase and then suppressed. The effect comprised both IgM and IgG responses. Skin hypersensitivity tests did not reveal any effect on the cellular immune response. These findings may explain why particularly IgA is affected in patients taking phenytoin by the oral route, and why either reduction or elevation of IgA may occur.

Eighty-five seamen exposed to a variety of organic solvents and hydrocarbon compounds during their work on chemical tankers were compared with 59 unexposed seamen. Visual memory, auditory memory and visual abstraction were examined 14 days or more after the last solvent exposure. Multivariate analyses were performed to control the effects of confounding factors such as age, alcohol consumption, smoking, cerebral concussions and educational level. Significant correlations were found between increasing solvent exposure and poor results in tests of auditory memory and visual abstraction. These results indicate adverse psychological effects caused by chronic organic solvent exposure.

Diverticulum-like widening of one or several nerve-root sheaths was found in 24 of 136 patients examined by lumbar myelography. No clinical significance of the diverticula was demonstrated. The roots most commonly affected were the S 1 and S 2 roots, carrying approximately 60 per cent of the diverticula. A system of classification according to morphology and to size compared with the root involved is proposed. A relationship between magasac and arachnoidal diverticula is confirmed.