Electron microscopic morphometry

The fundamental concepts of morphometry, the principal correction factors for systematic errors and the basic principles of efficient sampling are outlined for quantitative morphology at the electron microscopic level of resolution. The important usefulness of correlating electron microscopic morphometry with complementary light microscopic morphometry is emphasized.     

Electron microscopic autoradiographic and electron microscopic immunohistochemical studies on the anti-HPO antibody-producing cells

The secondary immune responses in mouse popliteal lymph nodes to horseradish peroxidase (HPO) were studied by a combination of electron microscopic autoradiography and electron microscopic immunohistochemistry in order to clarify the relationship between antibody-producing and DNA-synthesizing capacities of the plasmacytic series. The anti-HPO antibody-containing cells, which increased in number 72 h after the secondary antigenic stimulation, were mainly immunoblasts and immature plasma cells. Immunoblasts containing anti-HPO antibody incorporated [³H]thymidine more actively than did immature plasma cells containing anti-HPO antibody. In 144 h after the secondary antigenic stimulation, antibody containing cells consisted mainly of mature plasma cells and immature plasma cells. Immature plasma cells containing the anti-HPO antibody incorporated a little [³H]thymidine, but mature plasma cells containing anti-HPO antibody did not incorporate any [³H]thymidine.     

Fungi that attack microscopic animals

The Botanical Review -     

Segmentation of microscopic cell scenes

Different methods for the automated segmentation of microscopic cell scenes are presented with examples. The techniques discussed include edge detection by thresholding, "blob" detection by split-and-merge algorithm, global thresholding using gray-level histograms, hierarchic thresholding using color information, global thresholding using two-dimensional histograms and segmentation by "blob" labeling. Methods are more robust against insignificant changes in the scene and perform more reliably as more a priori knowledge about the scene is incorporated in the segmentation algorithm. The inclusion of both photometric and geometric a priori knowledge can result in a high level of correct segmentations, the cost of which is increased computation time.     

Electron microscopic study of troponin

Troponin and its components or fragments were observed in an electron microscope by the use of the rotary shadowing technique. In freshly prepared troponin with low viscosity, globular particles were mainly observed. The size of the long axis of the particles was 13.2 +/- 1.3 nm and the size perpendicular to the long axis was 9.5 +/- 1.2 nm. The mean axial ratio was 1.4 +/- 0.3. Most of the particles observed in a stored troponin preparation, having a higher viscosity than that of fresh troponin, had a globular head with a thin tail, with the total length of 25.4 +/- 1.4 nm (head-tail type particles). The axial size of the globular portion was 8.3 +/- 1.2 nm and the tail length was 17.1 +/- 1.6 nm. Observation of various particles during the transitional stages indicated that, in the globular particles, the tail region of head-tail type particle was associated along the globular head region. Troponin T was a filamentous particle with 16.9 +/- 1.5 nm length. The 26K fragment of troponin T, which was devoid of the N-terminal 45 residues from troponin T, was a filamentous particle with the length of 14.4 +/- 1.3 nm. Troponin T1, one of two chymotryptic subfragments of troponin T, was a filamentous particle of 11.6 +/- 1.4 nm length. Troponin C.T in the presence of Ca2+ was a particle with a globular head (7 nm in size) and a tail of about 17 nm length. The Fab fragment of anti-troponin T1 formed regular transverse striations along the thin filament of rabbit skeletal muscle with a 38 nm period.(ABSTRACT TRUNCATED AT 250 WORDS)     

Macroscopic and microscopic intermesenteric communications

The aim of this study was to describe all levels of the intermesenteric communications because of their importance in vascular diseases of the colon. The connections of superior and inferior mesenteric networks are very important in cases of acute or chronic obstruction to prevent ischemia and necrosis. Angiograms of mesenteric arteries were studied (40), cadaverous large intestine samples with mesentery and feeding vessels were dissected (36) or injected with India ink solution (24) or methylmetacrylate Mercox (41). In 7.9 % of cases an intermesenteric connection was described, named anastomosis intermesenterica accessoria and classified according to Pikkieff's(1) proposal. The marginal artery in the left colic flexure forms an arch called Riolan's arcade(2) or Haller's anastomosis(3) and is present in 95 % of cases. Infrequent anastomosis between straight vessels and mighty plexuses in the intestinal wall were registered. There are no regional differences when compared to the rest of colon.     

Emperipolesis of hematopoietic cells in myelocytic leukemia. Electron microscopic and phase contrast microscopic studies

In case of blast crisis of chronic myelocytic leukemia, the blast cells contained several kinds of normal hematopoietic cells. The peroxidase reaction was strongly positive in the neutrophilic granules of the engulfed neutrophils. These engulfed cells appeared to be normal and the limiting membranes of the engulfing cells seemed to be intact. We speculated therefore that this phenomenon might be emperipolesis. In a case of chronic myelocytic leukemia and a case of acute myelocytic leukemia, some megakaryoblasts showed the same phenomenon. These megakaryoblasts did not phagocytize latex particles. The limiting membranes of the engulfing megakaryoblasts were stained with ruthenium red but those of the engulfed hematopoietic cells were not stained. By phase microscopy, the engulfed cells were actively moving inside the megakaryoblasts and it was observed that the engulfed cells were actually living within the engulfing cells. These results demonstrated that this phenomenon was emperipolesis. Observations with an electron microscope and the phase microscope are indispensable for distinguishing emperipolesis from phagocytosis.