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M Dobashi

Publications and source records attributed to M Dobashi.

At least 19 recordsLinked to original sources
PubMed1996

Ultrastructural localization of S-100 protein in rat popliteal lymph nodes, and very slight proliferative activity of follicular dendritic cells.

The purposes of this study were to examine the tissue distribution of S-100 protein in rat lymph nodes at the ultrastructural level with respect to the relationship between follicular dendritic cells (FDCs) and antigen transporting cells (ATCs), and to determine whether FDCs increase after secondary stimulation with sheep red blood cells (SRBCs). We examined the ultrastructural localization of S-100 protein in rat popliteal lymph nodes, and the density of S-100 protein-positive FDCs in lymphoid follicles, after secondary stimulation with SRBCs, on paraffin wax sections. We found S-100 protein expression in FDCs in all regions of lymphoid follicles, although FDCs in the central portion of lymphoid follicles showed stronger reactions than FDCs in the periphery. S-100 recognized ATCs weakly. At the border between the subsinus layer and the lymphoid follicles, ATCs were very close to FDcs. There were only two mitotic S-100 protein-positive cells in the lymphoid follicles of all specimens. The density of S-100 protein-positive FDCs in the lymphoid follicles in secondary stimulated rats was significantly lower than in primary stimulated rats. We suggest that S-100 protein expression reflects FDC development and supports a close relationship between FDCs and ATCs. FDCs may have only very slight proliferative activity through the FDC density in the lymphoid follicles decreased after secondary stimulation.

Animals↗
PubMed1996

A change in the localization of the region trapping immune complexes in rat popliteal lymph nodes during development of germinal centers, with regard to the distribution of follicular dendritic cells.

A study was conducted to clarify changes in the relationship between the region of immune complex (IC) trapping by follicular dendritic cells (FDCs) and the distribution of FDC during reaction of germinal centers (GCs), and to examine the relationship between the tridimensional shape of the IC-trapping regions and their two-dimensional shape. Five-week-old rats were given footpad injections of sheep red blood cells, and then their popliteal lymph nodes were excised between days 0 and 42, 24 h after injection of peroxidase-antiperoxidase complex (PAP) as an IC. The specimens were immunostained for PAP trapping on serial paraffin sections, and for S-100 protein as a marker of FDCs. It was found that during the GC reaction, PAP trapping became weak and then disappeared on the basal side of developing GCs where S-100 protein-positive FDCs were still present. All of the 1933 lymph follicles examined were found to trap PAP. Whereas the tridimensional shapes of the trapping regions showed similar patterns according to the development of lymph follicles, their two-dimensional shapes varied. We suggest that FDCs in primary follicles may differentiate into FDCs in the light zone and FDCs in the dark zone in secondary follicles. To evaluate each of the compartments of a lymph follicle more accurately, investigators should pay attention to the tridimensional shape of the compartment.

Animals↗
PubMed1995

Immunohistochemical analysis of dendritic/Langerhans cells in thyroid carcinomas.

Recent immunohistochemical investigations of thyroid carcinomas have revealed that dense infiltration by dendritic cells (DCs) is correlated with a favorable prognosis. The present study was done to clarify the frequency and characteristics of DC infiltration in thyroid carcinomas, and also cytokines associated with DC maturation and migration. Compared with follicular carcinomas, papillary carcinomas contained significantly higher numbers of DCs, interleukin (IL)-1 alpha- and tumor necrosis factor (TNF)-alpha-positive cells, and cells positive for two TNF-alpha receptors (p60 and p80). The centers of cancer nodules had large numbers of CD1a- and CD1c-positive DCs suggesting that they were Langerhans cells, whereas the periphery of cancer nodules and inflamed surrounding thyroid tissues had numerous CD1b-, L-M2- and X-12-positive DCs suggesting that they were interdigitating cells, as well as many CD1a- and CD1c-positive DCs. Neoplastic cells of papillary carcinomas were more frequently reactive with antibodies against IL-1 alpha and TNF-alpha than those of follicular carcinomas, and a good correlation between their immunoreactivity and the frequency of DCs was found. These data suggest that cytokines such as IL-1 alpha and TNF-alpha released from carcinoma cells and cells in the cancer stroma may regulate the infiltration and maturation of dendritic/Langerhans cells, and that this process may be better preserved in papillary than in follicular carcinomas.

Adenocarcinoma, Follicular↗
PubMed1995

The density and distribution of follicular dendritic cells in rat popliteal lymph nodes: a decrease in their density and a change in their distribution after stimulation.

To determine whether follicular dendritic cells (FDCs) increase after stimulation, and also to confirm the widely accepted finding that the density of FDCs in the light zone is higher than that in the dark zone, we examined the density of FDCs in lymph follicles of rat popliteal lymph nodes. Rats aged five weeks were stimulated by injection of sheep erythrocytes, and then examined 10 days later. Unstimulated rats were also examined. After embedding in paraffin, the removed lymph nodes were immunostained with anti-S-100 protein antibody as a marker of rat FDCs. The density of FDCs was determined by measuring the area of the lymph follicle and counting the number of S-100 protein-positive cells within it. The density of FDCs in the lymph follicles of stimulated rats was found to be significantly lower than in 5-week-old and unstimulated rats. The density of FDCs in the light zone was similar to that in the dark zone when germinal center bordering cells (GCBCs), distributed at the border between the dark zone and the adjacent corona, were counted as FDCs. We conclude that the density of FDCs in lymph follicles decreases after stimulation, and suggest that FDCs have no or only very slight proliferative activity under normal conditions. Investigators may need to consider GCBCs in order to understand how FDCs differentiate.

Animals↗
PubMed1994

Protection of thyroid cancer cells by complement-regulatory factors.

BACKGROUND: Clinical and experimental studies have suggested that complement activation may play a role in tumor cytotoxicity. Little information is available concerning the presence of complement activation and the localization of complement-regulatory factors in cells or tissues of malignant tumors. The aim of the present study was to examine, using immunohistochemistry and immunoelectron microscopy, whether the complement system is activated in tissues of thyroid carcinoma and whether thyroid carcinoma cells are protected from cell lysis by in situ complement activation. METHODS: Fresh tissues were obtained by thyroidectomy from 15 patients with papillary carcinomas, 7 with follicular carcinomas, and 5 with follicular adenomas. In addition, five specimens of histologically normal thyroid tissue and five specimens of chronically inflamed tissue adjacent to thyroid neoplasms were studied. Immunohistochemical and immunoelectron microscopic localization of complement components, C3d and C5b-9, and the complement-regulatory factors, such as s-protein, decay-accelerating factor (CD55), membrane cofactor protein (CD46), complement receptor types 1 (CD35) and 2 (CD21), and protectin (CD59), were examined in these tissues. RESULTS: The staining patterns of C3d, C5b-9, and s-protein were positive and homogeneous in the nonneoplastic and most neoplastic thyroid tissues. Immunoelectron microscopy showed these antigens were localized mainly on the subepithelial and vascular basement membranes and attached to the cell surface of thyroid follicular cells. Decay-accelerating factor (CD55) was present homogeneously on the basement membranes, on the basal cell border of the thyroid follicular cells, and often on the luminal surface of carcinoma cells. Both membrane cofactor protein (CD46) and protectin (CD59) were expressed strongly on the cell surface of almost all benign and malignant thyroid follicular cells. Membrane cofactor protein was expressed on both the basal and lateral membrane, showing cell-to-cell interaction, but rarely on the luminal surface, whereas protectin was expressed strongly on the luminal surface and often on the basal cell border but rarely on the lateral membrane. Neither complement receptor type 1 (CD35) nor complement receptor type 2 (CD21) was expressed on any thyroid follicular cells. CONCLUSIONS: The present study confirmed the presence of complement activation with subsequent deposition of C3d and C5b-9 complexes in thyroid carcinomas. It also indicated that thyroid carcinoma cells are protected from cell lysis because of complement activation in multiple phases by complete coverage of the entire cell membrane surface with complement-regulatory factors. These findings were similar to those found in nonneoplastic thyroid follicular cells.

Adenoma↗
PubMed1992

Follicular dendritic cell and ICCOSOMES in germinal center reactions.

The development and destination of immune complex coated bodies (ICCOSOMES) was investigated at the ultrastructural level in the germinal centers (GC) of murine lymph nodes after secondary-immunization with horseradish peroxidase. Immediately after a booster injection, large amounts of immune complex (IC) were trapped on the surface of the cytoplasmic extensions of follicular dendritic cells (FDC). Cytoplasmic extensions, consisting mainly of FDC processes with associated IC, formed complex lamellar labyrinth-like structures (LBS). We describe here morphological changes of LBS. Lamellar or stationary LBS before the injection sequentially changed into distorted, filiform, glomerated and transitional LBS. Around day 1, IC-coated cytoplasmic extensions developed into glomerated LBS (G-LBS) which were invaginated into their own cytoplasmic ends, which swelled up to several microns in diameter. Around day 2, tufts of the glomerated LBS were unlaced and dispersed as (ICCOSOMES) in the interstitium. Some ICCOSOMES were endocytosed by germinal center cells (GCCs) and transported to the Golgi apparatus and perinuclear space. These ICCOSOME-bearing GCCs were B220-positive and some produced specific antibody (spAb) in the perinuclear space indicating they are in the B cell lineage. ICCOSOME-ingesting GCCs are thought to be able to process the antigen and present it to T cells. This may be important in the development of plasma cells and memory cells which developed from the GC B cells.

Animals↗
PubMed1989

The development of porcine zona pellucida using monoclonal antibodies: I. Immunochemistry and light microscopy.

We established three monoclonal antibodies (Mabs) against the zonae pellucidae (ZP) of porcine oocytes, named STA-1, STA-2, and STA-3, and eventually we determined that they all reacted with the isolated ZP. Based on Western blotting without 2-mercaptoethanol (2-ME), STA-1 reacted with the 80,000-110,000 Mr component, STA-2 with the 42,000-63,000 Mr component, and STA-3 with the 40,000-80,000 Mr component of ZP. We immunohistochemically specified the components of porcine ZP reactive with the three Mabs during the course of follicular development. Each Mab reacted with both the ZP and the interfollicular cell space (IFCS). One ZP component, reactive with STA-2 and STA-3, was first produced in the primordial follicle and was not found at the cumulus follicle stage, which corresponds to the stage of large antral follicles more than 5 mm in diameter. Another ZP component, reactive with STA-1, was not produced until the secondary follicle stage, and was never found at the antral follicle stage. These results suggest that each ZP component is produced and secreted at a specific stage or stages of folliculogenesis.

Animals↗
PubMed1989

The development of porcine zona pellucida using monoclonal antibodies: II. Electron microscopy.

Following our previous study on the immunohistochemistry of porcine zonae pellucidae (ZP), we undertook the present study to localize the components of the ZP with immunoelectron microscopy, using three types of anti-porcine-ZP monoclonal antibodies (Mabs), named STA-1, STA-2, and STA-3. Some organelles of the oocyte were seen to react with STA-2 and STA-3 prior to ZP formation. As soon as a follicle began to mature, STA-2 and STA-3 reacted with the perinuclear space and the endoplasmic reticular membrane of the oocyte. The follicle first reacted with STA-1 at the secondary follicle stage. At this stage, the positive reaction involved the follicular cell layer as well as the oocyte and ZP. Positive reaction was scattered within and limited to the interfollicular cell space and was never found in the cytoplasm of follicular cells. At the antral follicle stage, the oocyte was surrounded by a thick, electron-dense ZP. A strong reaction was observed in the outer layer, but no significant reaction occurred in the inner layer. The convex and ragged outer margin of the ZP was characterized by the strongest reaction.

Animals↗
PubMed1989

Ultrastructural localization of Cu, Zn-SOD in hepatocytes of patients with various liver diseases.

The ultrastructural localization of copper, zinc-superoxide dismutase (Cu, Zn-SOD) in the liver of patients with acute hepatitis, chronic hepatitis, liver cirrhosis and alcoholic fatty liver was studied by means of the indirect immunoperoxidase technique. In hepatocytes Cu, Zn-SOD was found to be localized in perinuclear cisternae, rough endoplasmic reticulum (rER), vesicles and Golgi apparatus. The Cu, Zn-SOD was also detected around the lipid droplets in hepatocytes as well as on the cytoplasmic membrane in cases of liver cirrhosis. These findings suggest that Cu, Zn-SOD is produced in the rER in hepatocytes and protects the cells from cellular injury caused by superoxide anion radical in various disorders of the liver.

Endoplasmic Reticulum↗
PubMed1989

Ultrastructural analysis of HNK-1+ cells in human peripheral blood and lymph nodes.

HNK-1 positive (HNK-1+) cells in human peripheral blood and lymph nodes were comparatively analysed by means of immunohistochemistry and immunoelectron microscopy. In peripheral blood, the HNK-1+ cells were grouped into large granular lymphocytes (LGLs), small lymphocytes and intermediate forms, all of which had many fine cytoplasmic processes. Except for smooth-surfaced lymphocytes, they could not be distinguished from helper/inducer T (OKT4/Leu3a) cells and suppressor/cytotoxic T (OKT8/Leu2a) cells. In double staining, HNK-1+T3- cells and HNK-1+T3+ cells could not be clearly distinguished in terms of morphology, although the former contained many LGLs. The HNK-1+ cells in the lymph nodes accumulated in the light zones of the germinal centers (GCs). These cells were small to medium-sized lymphocytes with few electron-dense granules and exclusively co-expressed helper/inducer T cell antigens (HNK-1+T4+). Their cytoplasmic projections were interwoven with those of the follicular dendritic cells which trap immune complexes for a long duration. These configurations suggest that HNK-1+T4+ cells in GCs are engaged in an immunological regulation of germinal center cells. On the other hand, large blastic HNK-1+ cells were scattered outside the GCs and some of them were in the process of mitosis. Furthermore, HNK-1+LGL-like cells with a few large electron-dense granules were rarely seen. These observations indicate that the HNK-1+ cells in the lymph nodes may proliferate outside GCs and differentiate into LGLs with a strong natural killer function.

Adult↗
PubMed1989

Histopathological study of corpora amylacea pulmonum.

In this paper, we present a rare disorder which is known as corpora amylacea pulmonum. X-ray CT scanning showed an abnormal focus of the lung as a solitary mass with high density and spicular features around the surface. The resected lung tissue was characterized by the appearance of round, concentrically laminated acellular bodies about 40-80 microns in diameter. The bodies were usually found lying free in the alveolar space and surrounded by the exudate alveolar macrophages or multinuclear giant cells. Some of these macrophages were in a state of progressive degeneration. The bodies showed an affinity for Congo red and exhibited partial birefringence. Moreover, all the bodies had a strong positivity for the PAS reaction and anti lysozyme antibodies. The exudate alveolar macrophages and multinuclear giant cells also displayed reactivity for PAS and lysozyme in a similar manner to that of the bodies. Electron microscopically the bodies were fundamentally composed of fibrillar elements, which bore some resemblance to amyloid fibrils and probably accounted for the partial affinity of the bodies for Congo red. These amyloid-like fibrils were also found in the cytoplasm of the macrophages. This suggested that the concentrically laminated bodies in corpora amylacea pulmonum might be formed by sequential aggregation, fusion, coalescence and compaction of degenerated alveolar macrophages.

Aged↗
PubMed1986

Postnatal development of dendritic reticulum cells and their immune complex trapping ability.

The postnatal development of dendritic reticulum cells in the rat popliteal lymph nodes was electron microscopically investigated in relation to the appearance of immune complex trapping capacity. The popliteal lymph nodes of neonatal rat consisted of loosely arranged fibroblastic reticulum cells. In the following stage, the peripheral cortex and paracortex became distinguishable. The former was made up of an accumulation of small lymphocytes, scattered within a framework of reticulum cells. On te 28 th day, the first primary follicle appeared in the peripheral cortex. Simultaneously the immune complex could be trapped on the cytoplasmic membrane of reticulum cells, which were located in the central portion of the primary follicles. The early image of germinal centers appeared corresponding to immune complex trapping areas. In the well-developed secondary follicles, the immune complex trapping cells were mainly localized in the cap area. Their cytoplasmic membranes formed the dendritic processes, on which the distinct ability of trapping of the immune complex was recognized. It was demonstrated that the fibroblastic reticulum cells, forming the stroma of lymph nodes, were transformed into the typical dendritic reticulum cells with labyrinth structures in the cap area. Desmosomal junctions were often found, not only between the dendritic reticulum cells themselves, but also between the dendritic reticulum cells and lymphocytes. We suggest that the desmosomal junctions play a role as the channel for a transmission of immunological information.

Animals↗
PubMed1986

Electron microscopic study on amyloid fibril formation in human lymph nodes.

The purpose of this investigation was to clarify the mechanisms of amyloid fibril formation in human lymph nodes. In our present study, amyloid deposition was observed diffusely in all compartments of the lymph nodes. The deposition form showed extremely characteristic findings in its morphological features. Namely, amyloid deposits mainly consisted of clusters of round or oval nodules. Each amyloid nodule was frequently enclosed with long-stretched cytoplasmic processes of abutting reticulum cells and/or macrophages. Amyloid fibrils often formed parallel amyloid bundles radiating to outlying sections of the nodule from the center. The amyloid bundles closely adhered to the cytoplasmic membrane of not only the abutting reticulum cells, macrophages and sinus endothelium but also to the lymphocytes and plasma cells. In the central portion of the amyloid nodules, a concentric core was also observed. The most interesting finding was the intracellular formation of amyloid fibrils in all cells, such as macrophages, reticulum cells, foreign body giant cells and lymphocytes in the process of degeneration. Some fibrils localized in the limited area of the cytoplasm and others appeared in all parts of the cells, including the nucleus. Their cell membranes were missing in several areas and the cell organella had gradually dissolved. Finally the cell residuums were completely replaced by amyloid fibrils and transformed into a nodular structure with radiating bundles of amyloid fibrils.

Aged↗
PubMed1983

[Effect of cepharanthin on peripheral leukocytopenia caused by antineoplastic agents].

One of the problems in administration of anticancer drugs is a decrease of peripheral blood leucocytes which causes reduction of defense mechanism against various infections. In this study, for the purpose of protecting leucopenia after administration of anticancer drugs, an effect of cepharanthine which is a kind of alkaroid materials was examined in normal and tumor-bearing mice. Peripheral leucocytes of both normal and tumor-bearing mice receiving anticancer drugs gradually decreased during first two weeks, and in third and forth week they decreased rapidly. On the other hand, leucopenia was improved by simultaneous administration of anticancer drugs and cepharanthin; however, a complete repairment was hardly expected when anticancer drugs were continuously administered. A significant recovery of leucocytes was observed in mice receiving cepharanthin compared to those receiving only anticancer drugs. In any process of decreasing and recovering from peripheral leucocytes, proportions of differential counts of leucocytes were approximately identical. On the colony forming experiment for granulocytic stem cell (CFU-C) using bone marrow cells of normal, anticancer drugs-treated, and anticancer drugs plus cepharanthin-treated mice, it has been suggested that cepharanthin might have some influencing activity on hematopoietic cells or cell-mediated activity on hematopoiesis only in vivo.

Alkaloids↗