Electron microscopic observations of elastic fibres in the lung and aorta of tight-skin and beta-aminopropionitrile-fed mice.

The lung of the tight-skin (TSK) mouse was characterized by enlargement of the air spaces. Elastin in the alveolar walls of the TSK mouse exhibited fragmentation. The aorta of the TSK mouse was characterized by marked hyperplasia of loose connective tissue in the adventitia. Collagen fibres and ruthenium red-positive materials were markedly increased. Microfibrils surrounding elastin in the adventitia of the aorta were not clear in the TSK mouse. In the lung of the beta-aminopropionitrile (BAPN)-fed mouse, enlargement of the alveolar air spaces was not prominent compared with the TSK mouse. Elastic fibres in the alveolar walls did not show the fragmentation observed in the TSK mouse, and microfibrils surrounding elastin were clearly observed. However, elastic laminae in the media of the BAPN-fed mouse aorta were swollen and fragmented. Elastic fibres in the adventitia exhibited a normal appearance and microfibrils surrounding elastin in the adventitia were clearly observed. The results suggest that the mechanism of the connective tissue abnormality in the TSK mouse is different from that of BAPN, which inhibits the activity of lysyl oxidase. The abnormality of elastin and microfibrils surrounding elastin in the TSK mouse probably plays a role in the deformity or degradation of elastic fibres and the structural changes of the lung.     

椰毒假单脆菌的电镜观察

A strain of food-poisoning bacterium has been isolated by Jin Jiexiang (1963) in China from the fermented cornflour that has gone bad. These pathogenic microorganism has been identified and named Pseudomonas by Zhao Naixin in 1988, which is the same species as P. cocovenenans. The characteristics of them were conformed to these of the species P. cepacia of section 2 of the genus Pseudomonas. In view of the fact that the fine structures of the above mentioned three strains of Pseudomonas have not been described yet, we decided to observe them with electron microscope. Results indicate there are many things in common among the three strains, such as: appearing short rods, 0.6-0.8 microns in diameter by 1.5-2.0 microns in length, one polar multiflagella; non-pili, non-capsules, non-endospores; containing intranuclear inclusions (electron-dense bodies or concentric laminae bodies), accumulating intracytoplasmic PHB granules; forming filaments, minicells and bizarrecells; producing extracellular cellulose-like materials by the three strains have not been reported previously.     

Electron microscopic observations of synaptic endings in cultures of mammalian central nervous tissue

Summary Synapses were found in rat cerebellar and brainstem cultures with the electron microscope. Three distinct types of synaptic terminals were described. The similarity between synapses found in vitro and in vivo was emphasized.Supported by USPHS Grants 5 Tl 459-04 and NB 03114-03S1 from the National Institutes of Health, Bethesda, Maryland.The authors wish to express their sincere appreciation to Mrs. Eleanor Morris for her assistance in preparing the cultures and Mr. Earl Pitsinger for his photographic assistance.     

Electron microscopic observations on ciliated epithelium of tracheal organ cultures infected with Bordetella bronchiseptica

Using mouse tracheal organ cultures, the pathogenic effect of Bordetella bronchiseptica to epithelial cells was studied by electron microscopy. The ultrastructure of epithelial cells in uninfected tracheal rings was preserved well for longer than 3 days. In mouse tracheal rings infected with graded doses (3 x 10(5) to 10(7) CFU/ml) of phase I B. bronchiseptica, the colonization in the interciliary spaces of ciliated epithelial cells was observed after a 20-hr infection period. The infected tracheal rings showed swelling of nonciliated cells as well as ciliated cells, rupture of cell membrane of cilia, swelling and disappearance of cilia, and atrophic cytomorphosis of epithelial cells. The severity of these changes occurred depending on the infection doses. These changes were essentially similar to those observed previously in the tracheal epithelia of the B. bronchiseptica-infected mice. The usefulness of this in vitro model was suggested for studying the pathogenesis of Bordetella infection.     

Electron microscopic observations on the cholesterol distributed in the epithelial cells of the gallbladder.

Epithelial cells of eight human gallbladders with cholesterosis were examined. In the supranuclear portion of the epithelial cells of one case, many spicular, circular and plate-like crystalline structures are present. Spicular and circular structures have not a limiting membrane, but plate-like structures are apparently bounded by a limiting membrane that clearly shows trilamellar structure. After digitonin treatment, the spicular and circular crystalline structures become denser. On the other hand, the plate-like structures do not become denser by digitonization. In the epithelial cells that contain no crystalline structure, there also occur many reaction precipitates after digitonization. These findings may suggest that free cholesterol is highly present in the epithelial cells of gallbladder with cholesterosis and that it, in some case, precipitates in the form of spicular or circular structure for the rapid fixation process.     

Electron microscopic observations on extraneuronal lipofuscin in the monkey brain

Protein synthesizing activity of the rat hypothalamic arcuate nucleus following partial or total deafferentation of the medial basal hypothalamus was studied by light and electron microscopic autoradiography when administering tritiated leucine into the lateral ventricle. There were significantly more grains over the arcuate nucleus 21 days after disconnection of this hypothalamic region than over the intact nucleus. Isolation of a temporal cortical region induced similar changes in the isolated area, although this effect was not so pronounced as in the arcuate region. Data suggest that the protein synthesizing activity of arcuate neurons increases significantly after interruption of neural connections of the medial basal hypothalamus. It is assumed that the effect is primarily due to transneuronal alteration and/or interruption of inhibitory afferents.