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Catecholamine and serotonin injected i.p. to new-born mice caused gliomas, ependymomas and choroid plexus papilloma together with multiple APUDomas within 48 hours after injection. We consider that an error in neural crest DNA may be caused through an adenylate-cyclic AMP system and Ca++ during replication and/or transcription. Multiple brain tumors caused by catecholamine and serotonin give the presumptive evidence that stem cells of neuroglia may be of neural crest origin.

Whether the embryopathic effects of ethanol are due to a deficiency of gamma-linolenic acid (GLA) or its metabolites was investigated by treating chick embryo with ethanol together with efamol, a rich and natural source of GLA. In contrast to findings in the rat, efamol did not protect the chick embryo from the deleterious action of ethanol. This might be due to species differences and the inability of the early chick embryo to metabolize the precursor fatty acids.

Quantitative-histological investigations (point counting method) are pointed out in 27 male and 15 female sand rats. The animals are divided in the IGT (impaired glucose tolerance), the diabetic and the control group. The LEYDIG cells are in the IGT-group increased, and in the diabetic group decreased. The female sand rats are characterized by the tendency of increase of size and number of follicles in the IGT-group. Corpora lutea are reduced but atretic follicles are increased in the diabetic group. The ovaries are greater in diabetic sand rats.

Observations on the ultrastructural appearance of the surfaces of the mature os penis in the rat reveal that a majority of its surfaces may be classified as prolonged resting surfaces on very slow growing surfaces. Although a vast majority of the bone consists of bone tissue types which usually only form a small part of human and laboratory animal bones, their surface appearances resemble to a high degree surface appearances described for ordinary bone tissue types. Thus, surface morphology need not reflect tissue type variance. However, certain minor deviations from usual descriptions of surface appearances were observed. Such deviations are for instance the combination of partly mineralized fiber bundles and a fully mineralized amorphous ground substance on some of the observed surfaces. The combination may be a result of an extremely slow growth or a lost ability of the ageing bone forming cell to produce organized tissue.

To confirm a hypothetical idea that the masticatory system will play a fundamental function in the postnatal growth of the body, the centripetal mastication-related information flowing in the system was interrupted by cutting the infraorbital nerve on the newborn mice. The sham- and axotomy-operation mice were returned to their mother. 20 days after the operation the sensory input unit was studied in the serial frontal section histologically. On the other hand the body weight was measured every 5 days after the operation and the significant level was examined statistically. The results obtained are as follows: 1) The sensory input units (primary and secondary sensory neurons) have completely reduced to disappear in situ. 2) The significant differences between both groups were seen at the level of P less than 0.001 from the period of 20-day after the operation. In comparison with that of the sham-operation mice, the axotomy-operation mice have decreased about 20 to 30% in the body weight and so reduced in shape, characterized by the smaller head, a shorter trunk and limbs and a shorter, thinner tail. The experimental data suggest that the centripetal mastication-related information plays an important role in the postnatal growth of the masticatory system and the other functional systems of the body.

An investigation by electron microscope was performed on the submandibular gland of unweaned cats for studying its morphology and carbohydrate histochemistry. The cytoarchitecture was comparable with that of adult animals with the exception of the degree of membrane merging in both demilunar and acinar cell secretory granules. Conversely, the submandibular gland of unweaned cats showed a peculiar HID-TCH-SP reactivity at acinar cell level.

The topographical distribution of motoneurons innervating the digastric muscle in the rabbit and guinea pig was re-examined by the retrograde tracing method of HRP (horseradish peroxidase). Motoneurons innervating the anterior belly of the digastric muscle of the rabbit and guinea pig constituted a longitudinal cell column in the ventromedial part of the motor nucleus of the trigeminal nerve. Motoneurons innervating the posterior belly of the digastric muscle were localized in the accessory facial nucleus. No motoneurons supplying the digastric muscle were found within the main facial nucleus.

Annulated gap junctions have been studied electron microscopically in normal rat embryo neural tube on day 12 of gestation. Localization, size and content of annulated gap junctions were characterized. Like in other tissues annulated gap junctions are thought to be involved in a degradation cycle of gap junctions.

The study was undertaken in 10 formol-imbibed kidneys of great anteater (Myrmecophaga tridactyla). After the dissection the following characteristics were showed: kidney blood vessels are distributed in 2 different sites, namely hilar and extrahilar, amounting 3 to 6 in the right side 3 to 7 in the left side. Arterial branches in extrahilar region range from 1 to 2 in both sides and in hilar region they present from 1 to 4 in the right and 1 to 2 in the left. Venous roots occur in 1 to 2 vessels in the right and 1 to 3 vessels in the left, occupying only the hilar region, except one case where it was present in the right side.