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Biomedical subjects

K Takaya

Publications and source records attributed to K Takaya.

At least 73 records · Page 4Linked to original sources
PubMed1989

Follicular dendritic reticular cells in the germinal center of the rat lymph node as studied by immuno-electron microscopy.

Follicular dendritic cells (FDCs) in the lymph follicles extend many dendritic cytoplasmic processes and are embedded among abundant lymphoid cells of the germinal centers, making it difficult to visualize their profiles and clearly identify their precursors. In rats pre-immunized with horseradish peroxidase (HRP), three cell types revealed a positive HRP reaction in the germinal center of the lymph node. One type was the typical FDC with remarkable cytoplasmic processes showing complicated invaginations. The second type comprised cells which were associated with reticular fibers enclosed by their cytoplasmic processes. These cells possessed fewer cytoplasmic processes than the typical FDCs, but their cytoplasmic invaginations were remarkable. Cells of the third type were attached to the outside of capillaries. Some of them surrounded reticular fibers with their cytoplasmic processes, while others extended complicated cytoplasmic processes like those of the typical FDCs. These observations support a new view that FDCs belong to the reticular cell population. Reticular cells, which generally are considered to be a mere supportive structure in lymph nodes thus are presumed to have the potential to transform into FDCs, thereby playing a role in the immune response.

Animals↗
PubMed1988

[Assessment of the discriminant analysis concerning the prognostic factors in patients with differentiated thyroid cancer].

We reported the result of our discriminant analysis concerning prognostic factors in differentiated thyroid cancer, which based on 134 cases obtained from three hospitals. The sensitivity, specificity and false-negative rate were 59%, 61% and 22%, respectively. When these values were estimated individually in each hospital, the figures were better than those obtained from a whole group of patients. The purpose of this paper is to assess the reliability of the previous result. Simulation was done to assess the relationship between the number of patients and the ratio of criterion variables. New groups were made from the 134 patients by random sampling. In each group, discriminant analysis was done by using the same nine explanatory variables as in the previous report (age, sex, diameter of tumor, site of tumor, histology, local invasion, lymph node metastasis, operative method and lymph node dissection). The results revealed that sensitivity was relatively stable but specificity and false-negative rate were better in the smaller group of patients. The ratio of criterion variables had an effect on the results. In the higher ratio, sensitivity was higher and the false-negative rate was lower.

Adenocarcinoma↗
PubMed1987

Light- and electron-microscopic study of the endolymphatic sac of the tree frog, Hyla arborea japonica.

The endolymphatic sac of the tree frog and its crystals were observed by light- and electron microscopy. Scanning electron microscopy revealed that the crystals have a faceted body and two pointed ends. Light- and transmission electron microscopy revealed that the endolymphatic sac is composed of many small chambers. In their lumina, numerous "ghosts" of crystals that resulted from decalcifications were observed. The ghosts were demarcated by a linear dense material or embedded in a flocculent substance. The epithelium of the endolymphatic sac is simple squamous or cuboidal and peculiar cytoplasmic granules are found in most cells. The granules are surrounded by a limiting membrane and have varying electron density. Some granules contain a core and/or tubular structures. Vacuoles containing large ghosts are also found in the epithelial cells. These ghosts were quite similar to those in the lumen and sometimes coexist with cell debris. The fine structure of the endolymphatic sac and its crystals is discussed.

Animals↗
PubMed1987

Liddle's syndrome, an uncommon form of hyporeninemic hypoaldosteronism: functional and histopathological studies.

Liddle's syndrome was diagnosed in a 72-year-old man who presented clinically with hypertension and muscle weakness. This disorder has been characterized by hyporeninemic hypoaldosteronism, hypertension, hypokalemia and enhanced erythrocyte sodium influx. Administration of spironolactone failed to correct the hypertension and electrolyte abnormality, which subsequently improved with triamterene therapy and a low salt diet. However, suppression of the renin-angiotensin-aldosterone system remained unchanged after this treatment. In addition, an atrophic juxtaglomerular apparatus and hypertensive lesions in the arterioles were confirmed by kidney biopsy after triamterene therapy. Therefore, a process of intrinsic hyperactive distal sodium reabsorption, probably affected by aldosterone-independent sodium transport into erythrocytes, appears to be important in the pathogenesis of this syndrome. Triamterene therapy, which usually is performed in patients with this disease, might not be the ultimate therapy in the future even if electrolyte abnormalities were to be improved temporarily.

Aged↗
PubMed1986

The fine structure of atypical ciliated cells in the human gastric epithelium.

Gastric mucosa obtained from the body and pyloric portions of the human stomach were observed by light and transmission electron microscopy. Ciliated cells were found in two of 18 subjects examined, one patient with gastric ulcer and the other one with gastric adenocarcinoma. The ciliated cells were found in epithelia at sites away from the main lesions. The tissues containing ciliated cells showed intestinal metaplasia combined with mild chronic gastritis in both cases. The epithelial layer facing the gastric lumen was composed of columnar cells with numerous uniform microvilli and goblet cells. This epithelium extended to the superficial parts of the tubules surrounded by the lamina propria. The deeper portions of the tubules were composed of mucous secretory, endocrine, and rarely ciliated cells. These ciliated cells were provided with numerous cilia the numbers of which varied considerably from cell to cell. This was in contrast to the primary cilium which is usually single. The central part of the apical cell membrane was sometimes concave in the area from where cilia tended to arise. It was also observed that numerous basal bodies as well as mucus-like granules were contained in the same cell. The axonemal pattern was different from that of ordinary cilia and showed 9 + 0 and 8 + 1 patterns. In longitudinal sections it was found that one peripheral doublet was displaced to the center of the axoneme as it left the basal body.

Cilia↗
PubMed1985

Uptake of released mast cell granules by reticular cells of the rat lymph node.

Granules released from mast cells were examined by electron microscopy in regional lymph nodes of rats after the injection of a large dose of horseradish peroxidase (HRP). Thirty minutes after the injection, a large number of mast-cell granules were present in sinuses, most of which adhered to the surfaces of reticular cells and some to macrophages. Two hours after the injection, a number of granules had been taken up by both reticular cells and macrophages. Reticular cells took up more granules than macrophages. Twenty-four hours after the injection, granules were scarce in both types of cells and in the extracellular space. Reticular cells surely participate in dealing with released mast-cell granules in the lymph node. Fibronectin bound to all mast-cell granules was demonstrated by immunohistochemistry. Fibronectin probably enables negatively charged mast-cell granules to approach negatively charged cell surfaces to be taken up by both reticular cells and macrophages.

Animals↗
PubMed1985

Acid-phosphatase activity of reticular cells and macrophages in the lymph node of the rat after ingestion of mast-cell granules.

Acid phosphatase (ACPase) was ultracytochemically demonstrated in the lymph-node sinus reticular cells and macrophages of rats. After the uptake of horseradish peroxidase (HRP), marked ACPase activities were seen in both reticular cells and macrophages, although only sparse ACPase activity was detected in the reticular cells of the control. After the injection of HRP into the footpad, the mast cells in the regional lymph node became degranulated, and the released granules were taken up by reticular cells and macrophages. In macrophages, these taken-up mast-cell granules exhibited ACPase reaction products, whereas none of the granules taken up by reticular cells showed ACPase activity. The heparin-protamine complex was also engulfed by reticular cells and macrophages, and ACPase activity was demonstrable in the complex taken up by both types of cell. It is probable that, as is the case in macrophages, reticular cells in the lymph-node sinuses take up and digest foreign substances through the formation of phagolysosomes, but they do not digest granules originating from the mast cells in the lymph node of the same animal.

Acid Phosphatase↗
PubMed1985

Skull metastasis of thyroid carcinoma. Study of 12 cases.

Over the past 33 years the authors have treated 12 cases of skull metastasis from thyroid carcinoma, accounting for 2.5% of a total of 473 cases of thyroid cancer. A study of these 12 cases revealed the following characteristics. The mean age of the patients was 60.4 years and the predominant incidence was in the seventh decade of life. The incidence of skull metastasis from thyroid cancer was higher among women than among men. The primary sign was a soft hemispheric tumor resting on the skull. The tumors were rich in vascularity with osteolytic changes in the skull. The average period from diagnosis of the thyroid tumor until thyroidectomy was 14.3 years, and until discovery of the skull metastasis was 23.3 years. The clinical course was thus very long. The most frequent histopathological presentation was follicular adenocarcinoma. Such lesions were morphologically well differentiated, with little pleomorphism and atypism, but detailed examination showed infiltration into the vascular lumen or capsule. The mean survival time in these patients was 4.5 years from the time of diagnosis. The prognosis in this lesion was relatively poor, considering its long clinical course.

Adult↗
PubMed1984

Intercellular junctions between macrophages in the regional lymph node of the rat after injection of large doses of steroids.

Intercellular junctions were often found between macrophages in sinuses of regional lymph nodes of the rat after injection of large doses of cholesterol, cortisone acetate, and estrone at the footpad. They were identified by subplasmalemmal densities, 20-50 nm in width, beneath the plasma membranes of apposed macrophages. No distinct filamentous structures were visible in those dense regions. Electron-dense amorphous materials are lined up at the center of the intercellular space in the junctional regions. Some macrophages form clusters with intercellular junctions. No significant difference in the effect of cholesterol, cortisone acetate, and estrone on the number of intercellular junctions between macrophages was found.

Animals↗
PubMed1983

Vacuoles in macrophages and reticular cells of regional lymph nodes of the rat after injection of large doses of steroids.

The ultrastructure of macrophages and reticular cells of regional lymph nodes of the rat after administration of large doses of cortisone acetate, estrone, progesterone, and cholesterol in aqueous suspensions was investigated. A large number of vacuoles, most of which were surrounded by unit membrane, and lipid droplets not surrounded by unit membrane were observed in the cytoplasm of both macrophages and reticular cells. They were not seen in these cells of control animals and in experimental animals that had received smaller doses of these steroid hormones. After cholesterol injection, many lipid droplets were observed in the cytoplasm of macrophages. These observations suggest that steroids injected in suspension accumulate in macrophages and reticular cells of the regional lymph nodes. Electron-dense material was often present in vacuoles of macrophages but not in those of reticular cells.

Animals↗
PubMed1982

Fine structures of the basophil infiltration in regional lymph nodes of the guinea-pig after the intradermal injection of T cell mitogens.

Basophil-rich infiltrates in regional lymph nodes of guinea-pigs were demonstrated by electron microscopy after the intradermal injection of T cell mitogens (PHA and Con A). Basophils infiltrated the stroma of the lymph node via the postcapillary venules (PCV) and migrated to the paracortex. Prior to infiltration of the lymph nodes a cutaneous basophil hypersensitivity reaction was seen in the mitogen-injected skin. B cell mitogen (LPS) injection did not induce this response.

Animals↗