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Biomedical subjects

J Asai

Publications and source records attributed to J Asai.

At least 109 records · Page 6Linked to original sources
PubMed1987

Thymic epithelial reticular cell subpopulations in mice defined by monoclonal antibodies.

Thymic epithelial reticular cells (TER) are heterogeneous cell populations. Of 14 rat monoclonal antibodies (moAbs) raised against established cell lines of mouse thymic stromal cells (TSC), two were found to recognize TER subpopulations that exhibited distinct intrathymic distributions. MoAb B6TS-1 (IgG2a) recognized the cell-surface determinant mB6TS-1 on TSC in the subcapsular zone, cortico-medullary junction, and medulla. Double staining with antikeratin antiserum showed that, except in the cortex, the distribution of mB6TS-1 bearing cells highly corresponded with that of keratin-positive TER indicating that mB6TS-1 within the thymus was selectively expressed in a particular subpopulation of epithelial cells. Immunoelectronmicroscopy revealed clear polarity in the expression of mB6TS-1 on TER. In the subcapsular zone. TER adherent to fibrous capsule expressed mB6TS-1 on the cell surface that faced the lymphocytes. In the cortico-medullary junction, mB6TS-1 also was found on the side of the TER closely associated with the small blood vessels. The mB6TS-1-bearing cells in the medulla characteristically had cytoplasmic infoldings containing collagen fibrils and amorphous material but did not exhibit the polarity of mB6TS-1-bearing cells. The mB6TS-1-bearing TER were interconnected by desmosomes and tonofilaments, therefore, were easily distinguished from macrophages, dendritic cells, and other components of thymic stroma. In contrast, another moAb AKTS-1 (IgM) stained the keratin-positive TER localized in the subcapsular zone and cortex forming a fine meshwork but did not stain those in the medulla. MoAb B6TS-1 stained thymic nurse cells but not the central cells of thymic rosettes, whereas moAB AKTS-1 did neither. Formation of lymphoid-stromal cell complexes in vitro was not affected by either antibody.

Animals↗
PubMed1987

[A case of serous papillary cystadenocarcinoma of the ovary with hyperamylasemia].

A case of serous papillary cystadenocarcinoma of the ovaries with hyperamylasemia has been studied immunohistochemically, electron microscopically, and biochemically. Cellular localization of amylase in the tumor tissue was determined by biochemical analysis, using an indirect immunoperoxidase method. Electron microscopy revealed electron-dense granules located in the peripheral region of the cytoplasm of most tumor cells.

Amylases↗
PubMed1987

Reorganization of thymic microenvironments during development and lymphomagenesis.

Modulation of thymic microenvironments during ontogeny and lymphomagenesis in mice was studied with two rat monoclonal antibodies (moAb) which recognized distinct subpopulations of thymic epithelial reticular cells (TER). In adult thymus, the TER subpopulation stained by moAb B6TS-1 was localized in the subcapsular zone, cortico-medullary junction, and medulla. In fetal thymus, it was initially distributed throughout the rudiment, but after day 16 of gestation, it was rapidly redistributed to the locations seen in adult thymus. From an early stage of thymic lymphomagenesis, the TER bearing mB6TS-1 (epitope defined by moAb B6TS-1) in the cortico-medullary junction, in particular those associating with small blood vessels, proliferated and formed a characteristic network throughout the thymus, in which numerous growing lymphoma cells were entrapped. On the other hand, moAb AKTS-1 stained another TER subpopulation that was localized in the cortex in both fetal and adult thymus. Unlike mB6TS-1+ TER, mAKTS-1+ TER became increasingly sparser during lymphomagenesis. Selective proliferation of the mB6TS-1+ TER subpopulation in the cortico-medullary junction was seen in spontaneous, radiation-induced, and chemical-induced mouse thymic lymphomas. The possible biological significance of such modulation of thymic microenvironments in the natural history of lymphomagenesis is discussed.

Animals↗
PubMed1986

The transverse tubular system of rat myocardium: its morphology and morphometry in the developing and adult animal.

The three dimensional arrangements of the T system in the developing and adult animal were investigated by means of high voltage electron microscope stereoscopy using Golgi treated materials. The rat myocardial T system was composed of three major group elements: the transverse tubules, longitudinal tubules and flattened cisternae, which were classified according to their orientation and to their morphological features. It was found, as the growth of the rats proceeded, that the longitudinal tubules increased in number and that the transverse tubules were arranged more regularly and densely at the level of the z band. The flattened cisternae transiently increased in number during the 2-9 weeks, and then decreased gradually. Electron microscopy also revealed that all the transverse, longitudinal tubules and flattened cisternae of the T system had the chance of forming a coupling with the sarcoplasmic reticulum irrespective of its morphology and orientation to the myofibrils. Quantitative analysis of the rat T system from the stereo images indicated that the surface area (0.299 micron2/micron3) was considerably greater than previously reported.

Age Factors↗
PubMed1986

Hepatic vascular endothelial cells heterogenously express surface antigens associated with monocytes, macrophages and T lymphocytes.

During studies of the antigenic and functional properties of hepatic sinusoidal lining cells in situ, we found that only the sinusoidal endothelial cells share antigens with a peripheral blood macrophage subset capable of presenting soluble antigens and triggering autologous mixed lymphocyte reactions. They were HLA-DR+, OKM1-, OKM5+. Vascular endothelial cells in the portal areas and central veins were HLA-DR+, OKM1- and OKM5-. The sinusoidal endothelial cells also expressed an antigen found on helper/inducer (OKT4 and Leu3 a) T lymphocytes. Thus, the present study suggests that endothelial cells in different anatomic compartments in the liver heterogenously express surface antigens associated with monocytes, macrophages and T lymphocytes and possess distinct immunological functions.

Antibodies, Monoclonal↗
PubMed1986

Microbial adjuvant and autoimmunity. IV. The induction of thyroid lesions in syngeneic X-irradiated mice by the transfer of spleen cells from mice immunized with thyroid extract and Klebsiella O3 lipopolysaccharide.

The role of humoral and cellular immune responses in the initiation and maintenance of autoimmune thyroiditis was investigated in mice immunized with syngeneic thyroid extract and Klebsiella O3 lipopolysaccharide (KO3 LPS) as an adjuvant. The transfer of spleen cells from hyperimmunized mice to 400R-irradiated syngeneic mice produced definite lesions in the thyroid glands, whereas the transfer of immune sera failed to do so. No lesions were induced in normal intact mice by the same transfer of sera and spleen cells from hyperimmunized mice. It was suggested that the induction of thyroiditis by immunization using KO3 LPS adjuvant is primarily due to cell-mediated immunity and that pretreatment of mice by X-irradiation is essential for production of the lesions. The role of X-irradiation in the induction of thyroiditis was discussed.

Adjuvants, Immunologic↗
PubMed1986

Observations on the fine structure of nodal, Purkinje and working myocardial cells isolated from rabbit hearts.

Sinoatrial and atrioventricular nodal cells as well as Purkinje and working myocardial cells isolated enzymatically from rabbit hearts were examined by transmission electron microscopy. The cardiac cell fine structure remained well organized in the storage solution after isolation. In normal Tyrode solution, the nodal cells changed from spindle shaped to spherical, whereas the shapes of Purkinje and working myocardial cells remained unchanged. The nodal cell fine structure became disorganized with respect to its sarcomeric arrangement in normal Tyrode solution. This was assumed to result from a combination of several factors seen in the nodal cells: the loss of the normal anchoring of the myofibrils at the previous intercalated discs, breakdown of the Z bands and the alteration of the integrity of the intermediate filaments. Also, extensive restoration of plasma membrane damaged by of the intermediate filaments. Also, extensive restoration of plasma membrane damaged by the isolation procedure was observed in this solution. This might correspond to the retention of the normal physiological properties of the plasma membrane of the nodal cells despite gross morphological changes undergone in normal Tyrode solution.

Animals↗
PubMed1986

Possible mechanisms of elevation of serum secretory immunoglobulin A in liver diseases.

In order to investigate possible mechanisms of elevation of serum secretory immunoglobulin A (sIgA) in liver diseases, human liver specimens were applied to immunohistochemical study of immunoglobulin A, secretory component, and J chain, which are components of sIgA. In the cases of chronic hepatitis with high serum sIgA levels, these antigens were present in dilated bile canaliculi of hepatocytes and they were continuously stained on the lateral plasma membrane of hepatocytes from the bile canaliculus to the space of Disse over the junctional complexes. Furthermore, in liver cirrhosis and extrahepatic cholestasis, they were also detected in intraportal bile ductules and intercellular spaces of degenerated cholangiocytes. These results suggest that at least two pathways might allow elevation of serum sIgA: through the communication of the bile canaliculus with the space of Disse over junctional complexes and through the bile ductule into the portal blood vessel.

Bile Canaliculi↗
PubMed1986

Enolase isozymes in renal tubules and renal cell carcinoma.

To elucidate the localization of enolase isozymes in renal tubules and renal cell carcinoma, an immunohistochemical study and quantitative analysis by employing the enzyme immunoassay were performed. The alpha-enolase was localized in almost all epithelial cells of renal tubules except for loops of Henle. The gamma-enolase was localized in macula densa cells and epithelial cells of loops of Henle and collecting ducts of the medulla, but not in those of proximal tubules. In renal cell carcinoma, most tumor cells possessed two enolase isozymes. From these immunohistochemical findings, it is suggested that enolases are present mainly in the alpha alpha form in epithelial cells of proximal tubules, in the gamma gamma form in those of loops of Henle, and in the two forms and/or the alpha gamma form in tumor cells of renal cell carcinoma. The levels of gamma-enolase in the normal cortex were 16.8 +/- 3.7 ng/mg protein (n = 7), whereas those in renal cell carcinoma were 928 +/- 554 ng/mg protein (n = 7), about 55-fold higher than those in the normal cortex. The serum gamma-enolase levels were also enhanced in 20 (49%) of 41 patients with renal cell carcinoma. Because it is generally accepted that renal cell carcinoma is derived from epithelium of proximal tubules, the expression of gamma-enolase has occurred during carcinogenesis.

Carcinoma, Renal Cell↗
PubMed1984

Cellular and humoral dynamics in the periarterial lymphatic sheaths of rat spleens.

Humoral and cellular dynamics in the periarterial lymphatic sheath (PALS) of the splenic white pulp were investigated in regards to the lymph flow and the architecture of the deep lymphatics in rat spleens. The effects of the splenic venous pressure on the lymph flow were also examined. We found a remarkable depletion of lymphocytes in the PALS and strong lymph flow to the deep lymphatics from the red pulp when the spleen was perfused via the splenic artery at a high speed with a high venous pressure. It was evident that lymphocyte depletion in the PALS depended on the venous pressure during the perfusion. Hemorrhage and lymphocyte depletion in the PALS also occurred after the ligature of the splenic vein. The migration of charcoal particles into the PALS via the red pulp was observed after intravenous or direct injection of charcoal particles. However, the bridging channels in the marginal zone (MZ) were always free of charcoal particles. The existence of deep lymphatics was confirmed around the central arteries which were more than 20 microns in diameter. The ligature of the thoracic duct resulted in the dilatation of the deep lymphatics and intercellular spaces which were easily recognized as the termination of the splenic lymphatics. The terminal lymphatics were localized only in the PALS but not in the follicles. Therefore, the PALS might be considered to act as a central station of the extra-vascular pathway which is connected to both the deep lymphatics and the MZ bridging channels.

Animals↗
PubMed1980

Adjuvant action of capsular polysaccharide of Klebsiella pneumoniae on antibody response. IX. Its effect on the histology of the regional lymph node and other lymphoid organs.

The sequence of histological changes in the regional lymph node and other lymphoid organs of mice injected with the capsular polysaccharide of Klebsiella pneumoniae (CPS-K) or bacterial lipopolysaccharide (LPS) was followed. Injection of CPS-K, but not LPS, induced the following characteristic histological changes in the regional lymph node. In the early stage there was a marked decrease in the number of small lymphocytes, accompanied by the appearance of scattered fragmented nuclei and infiltration of polymorphonuclear neutrophilic leukocytes, and in the late stage there was marked proliferation of macrophage-like cells and pyroninophilic cells. Histological changes in the thymus and spleen and changes in cell populations in the bone marrow and peripheral blood after CPS-K injection were essentially the same as after LPS injection. Since CPS-K has a much stronger adjuvant action on antibody response than does LPS, it is suggested that the characteristic histological changes in the regional lymph node after injection of CPS-K are closely related to its extraordinarily strong adjuvant action.

Adjuvants, Immunologic↗
PubMed1980

Microbial adjuvant and autoimmunity. IV. Production of lesions in the exocrine pancreas of mice by repeated injection of syngeneic pancreatic extract together with the capsular polysaccharide of Klebsiella pneumoniae.

Definite lesions in the exocrine pancreas were produced when SMA mice were immunized eight times at intervals of 30 days with a mixture of extract of pooled pancreas from syngeneic mice and the capsular polysaccharide of Klebsiella pneumoniae type I Kasuya strain (CPS-K), whereas no pancreatic lesions were produced in mice given CPS-K alone or pancreatic extract alone. The typical histological changes were characterized by infiltration with lymphocytes, plasma cells, and other mononuclear cells, degeneration and lysis of the acinar cells, destruction of the lobular architecture, and replacement of fatty tissue and fibrous connective tissue. The endocrine islets were well preserved. No specific histological changes were produced in the organs other than the pancreas in these mice. Most of mice immunized with pancreatic extract mixed with CPS-K produced serum precipitins to syngeneic pancreatic antigens. However, severe pancreatic lesions were also produced in mice showing no definite precipitin production.

Adjuvants, Immunologic↗
PubMed1979

Effect of capsular polysaccharide of Klebsiella pneumoniae on host resistance to bacterial infections. III. Further study of its effects on interactions between peritoneal leukocytes and virulent Salmonella enteritidis.

The mechanism for the infection-promoting effect of the capsular polysaccharide of Klebsiella pneumoniae (CPS-K) was investigated using the experimental system in which mice were infected intraperitoneally (i.p.) with a virulent strain of Salmonella enteritidis immediately after i.p. injection of CPS-K. In the peritoneal phagocytes of CPS-K-untreated control mice, approximately 70, 3, and 10% of phagocytized bacteria survived 6, 12, and 24 hr after challenge, respectively, when calculated from the ratio of the number of cell-associated viable bacteria, which was estimated by direct plate count, to the number of phagocytized bacteria, which was estimated by microscopic observation of stained smears. In contrast, almost all of the phagocytized bacteria were viable throughout the experimental period in mice treated with CPS-K. The electron microscopical findings of the phagocytes obtained 12 hr after challenge showed that in the cells of mice treated with CPS-K almost all of the phagocytized bacteria were morphologically intact, with some of them in the stages of cell division, whereas in those of untreated control mice, almost all of the phagocytized bacteria underwent digestive changes. When the reaction product of acid phosphatase was examined by electron microscopy in the phagocytes obtained 12 hr after challenge, the enzyme activity in the phagosomes was very low in mice treated with CPS-K in comparison with that in untreated control mice. Enzyme assays of the lysosomal and extralysosomal fractions of peritoneal cells obtained at various times after challenge also showed that release of acid phosphatase from the lysosomal fraction to the extralysosomal fraction after bacterial challenge was inhibited in peritoneal cells of mice treated with CPS-K.

Acid Phosphatase↗