Intercellular bridges of chick blastoderm studied by scanning and transmission electron microscopy.

Chick blastoderms were studied by scanning and transmission electron microscopy to identify by both methods a type of thread-like structure lying on the epiblast. The structure was identified by transmission microscopy as a long telophase bridge containing mid-body and spindle remnant. It appears to provide cytoplasmic continuity between only 2 cells.     

Primary neural induction as studied by scanning electron microscopy

Summary Normal primary neural induction has been studied by scanning electron microscopy and the results compared with those obtained by TEM. Mesoderm cells are usually in contact with several other cells, both mesodermal and endodermal in origin. By SEM the ectoderm layer has been shown to be in contact with the underlying mesoderm cells. Tufts of fibrous basement membrane are also present between the two cell types. TEM specimens also show an intermediate basement membrane.Acknowledgments. M. A. E. would like to thank ProfessorF. Beck in whose department this work was conducted. An especial acknowledgment to Mrs.Wendy Nugent for her skilled technical assistance in the preparation of the SEM and TEM specimens. Mr.Duncan Boreham, Electron Microscope Unit, University of Leicester kindly offered assistance and advice.S. V. C. would like to thank ProfessorR. P. Dale in whose department the SEM photographs were prepared.     

Primary neural induction as studied by scanning electron microscopy.

Normal primary neural induction has been studied by scanning electron microscopy and the results compared with those obtained by TEM. Mesoderm cells are usually in contact with several other cells, both mesodermal and endodermal in origin. By SEM the ectoderm layer has been shown to be in contact with the underlying mesoderm cells. Tufts of fibrous basement membrane are also present between the two cell types. TEM specimens also show an intermediate basement membrane.     

Location of lectin receptors on rat hepatocytes by transmission and scanning electron microscopy

Summary Rexeptors for various lectins have been located on isolated hepatocytes by transmission and scanning electron microscopy, using gold markers of variable sizes. Quantitative data indicated that binding of some lectin markers depended upon their sizes.Acknowledgments. The authors thank Miss E. Bujard and Mr. A. Isely for the rat liver perfusion and Mrs M. Weber for the photographic work.     

Choroidal vascular repair: scanning and transmission electron microscopy.

Repair of the choroidal vasculature following laser photocoagulation in the rat was examined with vascular casts and correlated with observations on thin-sections. The regenerative process began at the periphery of the damaged area, starting from the surviving choriocapillaris and venules, and proceeding towards the center by means of recanalization of damaged vessels and growth of new ones. In small healed lesions the capillary bed was re-formed. It resembled the adjacent undamaged choriocapillaris morphologically but appeared to be less dense than the intact choriocapillaris when examined by scanning microscopy. In large lesions the capillary bed was re-formed at the periphery but not at the center. Also present at the edges of the large lesions were groups of new vessels which, when observed by scanning microscopy, appeared to extend in two directions; towards the subretinal space and towards the choroidal network. Another aspect of the repair process was the simultaneous occurrence of new vessel growth and capillary regression, which was observed both at the level of the choriocapillaris and at the foci of new vessels.     

Microorganisms seen by scanning and transmission electron microscopy in Legionnaires' disease from human lung

Summary In addition to several anomalous structures, other general forms of definitely rod-shaped microorganisms have been found by scanning and transmission electron microscopy in the lung tissue taken at autopsy from a patient who succumbed to confirmed Legionnaires' disease with extensive necrotizing lobar pneumonia. The microorganisms were greatly varied in size and shape. They were micrographed in the act of fission. These forms have been found to some extent throughout the tissue. No nickel was demonstrated, either in the lung tissue or in the microorganisms.This work has been supported in part by a Henry Ford Hospital institutional grant from the Ford Foundation and in part by the Veterans Administration Medical Center Research Funds.     

Microorganisms seen by scanning and transmission electron microscopy in Legionnaires' disease from human lung.

In addition to several anomalous structures, other general forms of definitely rod-shaped microorganisms have been found by scanning and transmission electron microscopy in the lung tissue taken at autopsy from a patient who succumbed to confirmed Legionnaires' disease with extensive necrotizing lobar pneumonia. The microorganisms were greatly varied in size and shape. They were micrographed in the act of fission. These forms have been found to some extent throughout the tissue. No nickel was demonstrated, either in the lung tissue or in the microorganisms.     

Observation of Schistosoma mansoni by scanning electron microscopy]

The integumental surface of adult Schistosoma mansoni was studied by scanning electron microscopy (SEM) at 220 to 10,000 magnifications. SEM shows certain basic features such as spines in the oral sucker and the acetabulum which may facilitate rasping and attachment of the parasite to stay in the bloodstream of the definitive host. It seems likely that SEM visualization will be a means for differentiation some species of the genus Schistosoma.     

The Purkinje fiber-myocardial cell region in the goat heart as studied by combined scanning electron microscopy and chemical digestion

Summary The 3-dimensional architecture of the junctional region between Purkinje fibers and ordinary myocardial cells has been closely studied by combined scanning electron microscopy and chemical digestion in the goat heart. It was revealed that the Purkinje fibers forming the terminal arborization of the atrioventricular bundle are followed by transitional cells which are in contact with ordinary myocardial cells.Acknowledgment. We wish to thank Professor M. Murakami and Professor K. Yamada for encouraging this study.     

The Purkinje fiber-myocardial cell region in the goat heart as studied by combined scanning electron microscopy and chemical digestion

The 3-dimensional architecture of the junctional region between Purkinje fibers and ordinary myocardial cells has been closely studied by combined scanning electron microscopy and chemical digestion in the goat heart. It was revealed that the Purkinje fibers forming the terminal arborization of the atrioventricular bundle are followed by transitional cells which are in contact with ordinary myocardial cells.     

Localization of concanavalin-A binding sites inTetrahymena by scanning electron microscopy

Summary Binding sites of concanavalin-A were detected inTetrahymena on the body ciliature, while the cell membrane itself and the oral ciliature failed to bind the lectine.Supported by the Scientific Research Council, Ministry of Health, Hungary 1-01-0302-02-1/Cs.     

A transmission and scanning electron microscopic study of cytoplasmic threads of dividing neuroepithelial cells in early chick embryos

Summary Cytoplasmic threads found on the luminal surface of the developing chick neuroepithelium contain a remnant of the spindle complex and an electron-dense midbody. Most threads become long and thin and eventually split at the midbody. This finding suggests that the midbody plays a role in the final separation of daughter cells.This study was supported in part by grants from the Research Council and the Charles and Johanna Busch Memorial Fund of Rutgers University.     

Localization of concansvalin-A binding sites in Tetrahymena by scanning electron microscopy.

Binding sites of concanavalin-A were detected in Tetrahymena on the body ciliature, while the cell membrane itself and the oral ciliature failed to bind the lectine.     

Comparative study by scanning electron microscopy of synovial surfaces of four mammalian species

Zusammenfassung Die Oberflächen der Gelenke von Mensch, Kaninchen, Schwein und Ratte zeigen elektronenmikroskopisch feine zottenartige Bildungen. Daneben finden sich auch leichte Vertiefungen. Diese Bildungen sind für eine gleichmässige Gelenkbewegung von Wichtigkeit.     

Supramarginal cells in the rat pituitary cleft revealed by scanning electron microscopy

Summary An unusual cell type consisting of free elements widely scattered over the marginal epithelium of the rat pituitary cleft is revealed by SEM. Most of these supramarginal cells characteristically have irregularly shaped cell bodies from which thin branched processes extend. Supramarginal cells bear resemblances to Kolmer (epiplexus) cells and to supraependymal cells of the brain ventricles. Their ultrastructural features make it probable that supramarginal cells are phagocytes, and can be regarded as scavengers of the cleft. Considering the close topographical association between the hypophysial cleft and the floor or the 3rd ventricle, supramarginal cells may be members of the motile macrophagic Kolmer cells populating the ventricular surfaces of the brain.Work supported by grants from MPI-60%-193/84     

Supramarginal cells in the rat pituitary cleft revealed by scanning electron microscopy

An unusual cell type consisting of free elements widely scattered over the marginal epithelium of the rat pituitary cleft is revealed by SEM. Most of these supramarginal cells characteristically have irregularly shaped cell bodies from which thin branched processes extend. Supramarginal cells bear resemblances to Kolmer (epiplexus) cells and to supraependymal cells of the brain ventricles. Their ultrastructural features make it probable that supramarginal cells are phagocytes, and can be regarded as scavengers of the cleft. Considering the close topographical association between the hypophysial cleft and the floor or the 3rd ventricle, supramarginal cells may be members of the motile macrophagic Kolmer cells populating the ventricular surfaces of the brain.     

Choroidal vascular repair: Scanning and transmission electron microscopy

Repair of the choroidal vasculature following laser photocoagulation in the rat was examined with vascular casts and correlated with observations on thin-sections. The regenerative process began at the periphery of the damaged area, starting from the surviving choriocapillaris and venules, and proceeding towards the center by means of recanalization of damaged vessels and growth of new ones. In small healed lesions the capillary bed was re-formed. It resembled the adjacent undamaged choriocapillaris morphologically but appeared to be less dense than the intact choriocapillaris when examined by scanning microscopy. In large lesions the capillary bed was re-formed at the periphery but not at the center. Also present at the edges of the large lesions were groups of new vessels which, when observed by scanning microscopy, appeared to extend in two directions; towards the subretinal space and towards the choroidal network. Another aspect of the repair process was the simultaneous occurrence of new vessel growth and capillary regression, which was observed both at the level of the choriocapillaris and at the foci of new vessels