Three-Dimensional Configuration of Crypts of Different Types of Colorectal Adenomas

The three-dimensional configuration of isolated crypts of normal human colonic mucosa and colorectal adenomas was examined by scanning electron microscopy. For isolation of the crypts, the digestion method with HCl was used for formalin fixed tissues, and the separation method with ethylenediaminetetraacetic acid (EDT A) following ultrasonication was applied to fresh tissues. In a comparative study, the NaOH cell-maceration method, which visualized the sub-basal laminal collagen sheath, was applied. The isolated crypts from the normal colon were visualized as a single straight tubule resembling a test tube. Most isolated crypts of the tubular adenomas were visualized as elongated fan-like structures with several protuberances and a few short branchings. Their average length was more than twice that of the normal colonic mucosa crypts. Most crypts of the villous adenomas were visualized as slender tubules without protuberances and short branchings, and their average length was three times that of the tubular adenoma crypts. Most crypts of the tubulovillous adenomas were long and triangular with several longitudinal folds and protuberances, and the average length was about three times that of the tubular adenoma crypts

Scanning Electron Microscopic Study of the Three-Dimensional Structure of the Collagen Networks of Gastric Cancer

The three-dimensional structure of the collagen networks in human gastric carcinoma was examined by scanning electron microscopy (SEM) after treatment with the cell-maceration method using a low temperature NaOH solution. Based on stromal content, the poorly differentiated adenocarcinoma can be divided into the medullary carcinoma area and the scirrhous carcinoma area. In the medullary carcinoma, the collagen sheath around the small tumor cell acinus formed spherical chambers (20-30 μm in diameter) with fenestrations (about 5 μm in diameter) connecting the chambers. The collagen sheath was composed of fine collagen fibrils (about 50 nm in diameter). In the scirrhous area, there was abundant fibrous stroma composed of thicker collagen fibrils (about 100 nm in diameter). Tiny tumor cell nests were sporadically seen in the fibrous stroma. These tumor nests were surrounded by collagen fibrils (about 50 nm in diameter). In the moderately differentiated tubular adenocarcinoma, the tumors were surrounded by spherical, ovoid or irregular shaped thick collagen sheaths (50-200 μm in diameter), which were composed of loosely packed 50 nm collagen fibrils. In well differentiated tubular adenocarcinoma, tumor glands were surrounded by spherical, ovoid or irregularly-shaped thick collagen sheaths (50-200 μm in diameter), composed of densely arranged fine collagen fibrils. In papillary carcinoma, the collagen sheaths were nipple-shaped. They were composed of very densely arranged fine collagen fibrils (about 50 nm in diameter)

Scanning Electron Microscopic Study of the Collagen Sheath of the Human Thyroid Gland and Its Disorders

A cell-maceration/scanning electron microscope (SEM) method was employed to demonstrate the collagen sheath around follicles (perifollicular sheath) of the human thyroid gland and its disorders. In the normal thyroid gland, the follicles were surrounded by spherical collagen sheaths composed of a framework of thick collagen bands 1-5 μm in width and fine solitary collagen fibrils 50-70 nm in diameter. In benign thyroid diseases (Graves\u27 disease, Hashimoto\u27s thyroiditis and adenomatous goiter), the perifollicular sheaths differed in size and in shape according to the disease, but they were always composed of thick collagen bands and fine fibrils as in the normal thyroid. On the other hand, the spaces surrounded by the perifollicular sheaths varied markedly in size in follicular adenoma, were small in oxyphilic adenoma, and irregularly shaped in embryonal adenoma. In all these adenomas, the perifollicular sheaths were mainly composed of fine fibrils 35-45 nm in diameter. In follicular carcinoma, the size and shape of the space surrounded by the perifollicular sheaths were irregular. In papillary adenocarcinoma, the collagen sheaths showed a papillary pattern. In medullary carcinoma, tumor nests were surrounded by well developed collagen sheaths. In all these carcinomas, the collagen sheaths were mainly composed of fine collagen fibrils 32-45 nm in diameter. In adenomas and follicular carcinoma, the perifollicular sheaths frequently had large holes through which the spaces surrounded by the collagen sheaths connected to each other. Such holes were, however, rare in the normal thyroid and benign non-neoplastic thyroid diseases

Electron microscopic study of the initial stage of cellular and lymphatic invasion in carcinoma

The initial stages of cellular and lymphatic invasion were studied in experimental carcinomas of rat-stomach induced by N-methyl-N'-nitro-N-nitrosoguanidine. In initial invasion, lack of the basement membrane and cytoplasmic projections into the adjacent connective tissues was observed. The mode of penetration of cytoplasmic protrusion into the stroma was also studied in cases of benign cells. As a result, invasion by carcinoma cells was thought to occur with its ameboid and proteolytic enzymic action against the surrounding tissues. The invasive mode into the lymphatic vessels was divided into the following 2 types; a destructive invasion type, and an endothelium type. It was interesting that differentiation and cellular adhensiveness of carcinoma cells was less in the course of invading into the lymphatic wall, but rose after that

Evolution of random synaptic weights of the hopfield associative memory : how chaotic trajectories turn into fixed point attractors?

We apply evolutionary computations to Hopfield's neural network model of associative memory. We reported elsewhere that a fully connected neural network with random synaptic weights evolves to create fixed point attractors exactly at the locations of patterns to be memorized by a genetic algorithm. In this paper, we present the process of the evolution from chaotic behaviors to an associative memory.http://library.naist.jp/mylimedio/dllimedio/show.cgi?bookid=100009601&oldid=1694