Polysialylated Neural Cell Adhesion is Involved in Target-induced Morphological Differentiation of Arcuate Dopaminergic Neurons

We have previously shown that the morphological and biochemical maturation of developing rat hypothalamic dopaminergic neurons is accelerated when they are cocultivated with pituitary intermediate lobe cells, one of their targets. Only two subsets of hypothalamic dopaminergic neurons (arcuate, A12, and periventricular, A14, nuclei) may project to the pars intermedia. In order to determine whether the two populations are equally responsive to coculture conditions, we microdissected the hypothalamus of 17-day-old rat fetuses in two fragments containing cell bodies from the A12 and from the A14 regions, prepared neuronal cultures from both portions and incubated them separately with intermediate lobe cells. The presence of intermediate lobe cells increased tyrosine hydroxylase levels in both dopaminergic neuron subsets, but morphological differentiation was accelerated in dopaminergic neurons originating in the arcuate nucleus only. We then investigated whether physical contact between developing arcuate neurons and their target cells was a prerequisite of the morphological effect by interposing a semipermeable membrane between cultivated neurons and intermediate lobe cells in transwell culture dishes. The morphological effect was no longer observed under transwell coculture conditions, pointing to the involvement of membrane-bound molecules. Accordingly, the stimulating effect of coculture on arcuate dopaminergic neurons was completely abolished by the removal of polysialic acid on neural cell adhesion molecules by endoneuraminidase N treatment. Thus, maturation of A12 and A14 dopaminergic neurons exhibits differential susceptibility to intermediate lobe target cells, and polysialylated-NCAM is required for the contact-dependent effect.     

A Morphometric Study of the Lungs after Blast lnjury in Rats

A lot of research work has been carriod out on thc lungs after blast injury, but nomorphomctric study of the blast-injured lungs has ever been reported so far.The authors quantifiedthe morphological changes of the lungs with blast injury in rats with stereological methods.t wasfound that following the blast injury,the pulmonary capillary volume and the intcmal surface arca de-creased significantly,while the arithmetic and harmonic mean thickness of the air-blood barrier andthe volume of polymorphonuclear leucocytes and platelets in the capillaries incrcased markedly.Themorphometric oxygen diffusion capacity of the lungs was remarkably reduced mainly due to the de-crease of the conductance of the air-blood barrier and erythrocytcs.In addition,the changes of theoxygen diffussion capacity of the lungs were closely related to the partial pressure of arteria/blood oxy-gen.These facts imply that the damage to the pulmonary capillaries was one of the main causes ofalveolar bleeding and early respiratory insufficiency.It is possible that a mathematic relationshipcould be established between the intensity of the blast impact and the consequent morphologicalchanges of the injured lungs.     

A sporadk case of Ehlers-Danlos syndrome type IV Diagnosed by a morphometric study of collagen content

A sporadic cam of a young woman with Ehlers-Danlos syndrome (EDS) type IV is hscrlbed. Multiple aneurysms of medium-sized arteries were noted. Histological study revealed deposition of acid mucopolysaccharides in the media of malor arteries and in the intirna of smaller arteries with Intimal thickenlng. Systemic changes related to stenosis were observed in arteries more than 100 μm in diameter. Histologic study revealed hyperplasia of adipocytes in the submucosal layer of the intestines and the trachea, and flbrosis of Langerhans' islets of the pancreas. Typical signs for EDS such as skin hyperelasticity and joint hypermobility, and posltive family history were not present. However, type III collagen was not detected on frozen sections from either the skin or the anterior cerebral artery by imrnunohistochem-ical quantification. Thus, it was concluded that the present case is a varlant of EDS.     

猕猴输精管结扎后前列腺及精囊腺的形态定量

目的：研究成年猕猴输精管结扎后前列腺及精囊腺的组织学结构是否发生变化。方法：成年猕猴输精管结扎1年后摘除前列腺和精囊腺，制作石蜡切片，根据体视学的点计数法估计前列腺、精囊腺内多种组织结构的体积分数及总体积。结果：与对照动物相比，结扎组前列腺与精囊腺的体积以及器官内多种结构的形态及其体积分数、总体积均无显著性改变。结论：猕猴输精管结扎1年未影响前列腺和精囊腺的结构。