Effects of carbon dioxide and oxygen on properties of experimental seizures in mice

The influence of various concentrations of carbon dioxide and oxygen on the pattern of maximal electroshock seizures (MES), on pentylenetetrazol (Metrazol)-induced seizures, and on recovery time (RT50) from MES has been studied in mice. The major results are summarized as follows: Increasing the concentration of carbon dioxide in 20% oxygen resulted in marked changes in the MES pattern. The duration of the tonic flexor component was increased, and the duration of the tonic extensor component and of the entire tonic phase was decreased; the ratio of flexion to extension was increased markedly. These changes indicate an anticonvulsant effect of carbon dioxide. Carbon dioxide in a concentration of 15.6% protected 50% of mice against a 97% convulsant dose (CD97) of Metrazol. Hypoxia, induced by inhalation of 15 or 10% oxygen, decreased the duration of the tonic flexor component and increased the duration of the tonic extensor component of the MES; the duration of the entire tonic phase was increased; the ratio of flexion to extension was slightly decreased. These changes indicate an excitatory effect of low oxygen concentrations on the brain, under the stated conditions. Hyperoxia, induced by inhalation of 50, 75 or 90% oxygen, in contrast to hypoxia, resulted in effects on MES similar to those produced by inhalation of carbon dioxide. The RT50 was slightly, but not significantly, decreased by hypoxia (15% oxygen), unchanged by hyperoxia (50% oxygen), and markedly increased by an increase in carbon dioxide concentration. Carbon dioxide (5 and 10%) combined with hypoxia (10% oxygen) produced effects on MES pattern and RT50 similar to those produced by carbon dioxide in 20% oxygen.

Juvenile Parkinson's disease with widespread Lewy bodies in the brain

A clinico-pathological case report on a case of juvenile Parkinson's disease (JPD) with widespread Lewy bodies (LBs) in the brain is presented with comparative morphological studies on two demented cases of "classical" Parkinson's disease (CPD) with disease onset at an older age. The clinical and histological pictures of this JPD case were typical of Parkinson's disease, excepting numerous Lewy bodies in the cerebrum. There were no neurofibrillary change nor senile plaques throughout the CNS. The distribution and histochemical and ultrastructural characters of the histological lesions (i.e., LBs) in the JPD and the two CPD cases were investigated and compared. The comparison showed no qualitative but only quantitative differences between the two types of Parkinson's disease. The present study also revealed that in CPD cases significant numbers of LBs could be present in the cerebral cortex, amygdaloid and claustrum. These lesions can be in part responsible for dementia in CPD.