Ultrastructural recognition of dendritic cells in the intimal lesions of aortas of chickens affected with Marek's disease.

The present study was undertaken to determine whether dendritic cells contributed to the intimal abnormalities seen in the aortas of chickens infected with Marek's disease. Semithin sections were used to select aortic segments in which the intima was thickened by lymphocytic infiltrates. Ultrathin sections were then examined. Intermingled with lymphocytes within the intimal thickenings were cells with an appearance typical of dendritic cells including long processes and a unique tubulovesicular system. In these cellular processes the tubulovesicular system was hypertrophied with the tubular cisterns characteristically forming concentric cyclical layers. Our observations show that dendritic cells are present in the aortic lesions of Marek's disease and are presumably involved in related immune mechanisms.

Disorders of brain development in the progeny of mothers who used alcohol during pregnancy.

Brain development has been studied in 44 embryos (gestational age: 5-12 weeks) and three fetuses (gestational age: 14 weeks) obtained from mothers who used alcohol during pregnancy, and compared with a control group comprising 16 cases of comparable ages. In 34 cases out of 47 in the alcohol group (75.5%), features indicative of abnormal morphological brain development were found. In all, nine variants of brain pathology are described. Abnormalities in the formation of the lateral ventricle walls and disorders of the development of the cortical laminae occurred most frequently (70.6% and 57.9%, respectively). When the cases were sorted according to maternal alcohol intake it was found that the children of severely alcoholic mothers (100-500 ml ethanol per day, 4-7 days per week) had abnormal brain morphology in 100% of cases. In those cases where maternal alcohol use was systematic and frequent (100-200 ml ethanol per day, 2-4 times per week), brain pathology was identified in 83.3% of cases. In systematic maternal use of alcohol (100-200 ml of ethanol taken on one day per week), and in episodic use (35-100 ml of ethanol taken on three occasions during pregnancy), 97.3% and 28.5% were affected, respectively.

Serotonin as a stimulator of hippocampal cell differentiation in tissue culture.

The effects of serotonin (5-HT) on morphofunctional development of hippocampal cultures derived from newborn rats were studied. It was established that systematic addition of 5-HT to nutrient medium during cultivation stimulates neuropil development, axon myelination and synaptogenesis. Electrophysiological studies of hippocampal cells in 5-HT treated cultures showed earlier exhibition of spontaneous activity and an increased number of spontaneously firing neurons and prevalence of periodic (bursting) type of discharges. These results indicate that 5-HT stimulates the differentiation of hippocampal cells in tissue culture.