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Biomedical subjects

N Tsukada

Publications and source records attributed to N Tsukada.

At least 55 records · Page 3Linked to original sources
PubMed1995

Increased levels of soluble vascular cell adhesion molecule-1 (VCAM-1) in the cerebrospinal fluid and sera of patients with multiple sclerosis and human T lymphotropic virus type-1-associated myelopathy.

We evaluated the relationship between the soluble form of vascular cell adhesion molecule-1 (sVCAM-1) and disease activity in patients with multiple sclerosis (MS) or with human T lymphotropic virus type 1-associated myelopathy (HAM), and measured levels of sVCAM-1 in their cerebrospinal fluid (CSF) and sera. Serum and CSF levels of sVCAM-1 were significantly increased in patients with acute relapsing MS during an exacerbation (P < 0.01 and P < 0.001), as well as in chronic progressive MS (P < 0.05 and P < 0.001), compared with healthy individuals and patients with other neurological diseases, respectively. Patients with acute relapsing MS during an exacerbation also exhibited significantly higher serum and CSF levels of sVCAM-1 vs. patients with acute relapsing MS in remission (P < 0.001). Significantly higher serum levels of sVCAM-1 were observed in patients with HAM vs. either healthy individuals (P < 0.01) or non-HAM carriers (P < 0.01). These results suggest that the determination of sVCAM-1 in the sera and CSF may be useful in monitoring the activity of MS and HAM.

Adult↗
PubMed1995

Endothelial cell damage in sarcoidosis and neurosarcoidosis: autoantibodies to endothelial cells.

Damage to the vascular system, of which endothelial cells are the main constituent, may occur in sarcoidosis. Evidence of blood-brain barrier (BBB) disruption is shown in sarcoidosis with central nervous system (CNS) involvement by means of magnetic resonance imaging or computed tomography. We investigated the presence of antiendothelial cell antibodies by culture of endothelial cells derived from human umbilical cord vein and from human brain using an enzyme-linked immunosorbent assay, and the presence of circulating immune complexes using a Raji cell assay, in the sera of patients with sarcoidosis. The patients with sarcoidosis displayed significantly high levels of immunoglobulin G (IgG) binding to endothelial cells after blocking Fc receptor compared to controls (p < 0.01). The sera of neurosarcoid patients with CNS involvement still showed significantly increased levels of IgG binding to brain endothelial cells after blocking Fc receptor compared to controls and those of pulmonary sarcoidosis (p < 0.001 and p < 0.01 respectively). These results suggest that the presence of autoantibodies to endothelial cells may be involved in endothelial cell damage, including BBB disruption.

Adult↗
PubMed1995

Adhesion of lymphocytes to endothelial cells in experimental allergic encephalomyelitis before and after treatment with endotoxin lipopolysaccharide.

We investigated the in vitro adhesion of 51Cr-labeled lymphocytes to cultured brain endothelial cells and the in vivo expression of intercellular adhesion molecule-1 (ICAM-1) on cerebral endothelial cells in a rat model of experimental allergic encephalomyelitis (EAE) before and after treatment with lipopolysaccharide (LPS). Adhesion of lymphocytes to cerebral endothelial cells was significantly increased in EAE compared with controls (p < 0.01), and was significantly correlated with the percentage of major histocompatibility complex class II antigen-positive cells in lymph node cells (p < 0.001). LPS enhanced ICAM-1 expression on endothelial cells and lymphocyte adhesion to those cells, and caused a significant increase in the in vivo expression of ICAM-1 compared with controls (p < 0.001). Lymphocyte adhesion to endothelial cells was significantly blocked by monoclonal antibodies against ICAM-1, lymphocyte function-associated antigen-1, or very late activation antigen-4. Our findings suggest that lymphocyte adhesion to brain endothelial cells may contribute to lymphocyte migration across the blood-brain barrier in EAE and that LPS may cause progression of EAE lesions.

Animals↗
PubMed1995

Soluble E-selectin in the serum and cerebrospinal fluid of patients with multiple sclerosis and human T-lymphotropic virus type 1-associated myelopathy.

To evaluate the activation of endothelial cells of the brain and the spinal cord, we investigated the presence of soluble endothelial leukocyte adhesion molecule-1 (sE-selectin) in the serum and cerebrospinal fluid (CSF) of patients with multiple sclerosis (MS) and those with human T-lymphotropic virus type 1-associated myelopathy (HAM). There were significantly higher levels of sE-selectin found in the serum of patients with relapsing-remitting MS during an exacerbation (p < 0.001) and those with chronic progressive MS (p < 0.01) compared with controls. Serum levels of sE-selectin in patients with HAM did not differ significantly from serum levels in controls or non-HAM carriers. We also found sE-selectin in the CSF of eight patients during an exacerbation of relapsing-remitting MS. These results suggest that an active immune reaction involving E-selectin production that is indicative of endothelial cell damage occurs in the CNS of patients during an exacerbation of relapsing-remitting MS. Thus, sE-selectin may be useful in monitoring disease activity in patients with relapsing-remitting MS.

Adult↗
PubMed1995

The structure and organization of the bile canalicular cytoskeleton with special reference to actin and actin-binding proteins.

The distribution of actin filaments and actin-binding proteins in the bile canaliculus (BC) of normal human hepatocytes was determined as a means of establishing the structure and organization of the BC cytoskeleton. Immunoblots demonstrated that actin, and the actin-binding proteins, myosin II, tropomyosin, vinculin, alpha-actinin, villin, were present, as were the non-actin-related proteins beta-tubulin, and cytokeratins. Three actin filament regions were identified: microvillus core filaments, a membrane-associated microfilamentous network, and a circumferential pericanalicular actin filament band. Actin-binding proteins were nonrandomly associated with actin in these regions. In the case of the pericanalicular band, there was also association with the zonula adherens junction. Intermediate filaments inserted into desmosomes. The ultrastructural localization of the actin-binding proteins was fundamentally linked to the arrangement and organization of the major canaliculus-associated microfilament structures. Structural organization of the cytoskeleton was also linked to distinct components of the intercellular junctions. It is notable that tropomyosin and a-actinin, which in muscle cells are regulatory proteins of contractile activity, and myosin II are associated with the pericanalicular actin microfilament band; it is the BC counterpart of the contractile actin filament band found in the apical region of other secretory cells. The outer sheath of noncontractile intermediate filaments likely stabilizes the canalicular compartment.

Actins↗
PubMed1994

Isolation of the bile canalicular actin-myosin II motor.

Cytoskeleton-rich canalicular membranes (CCMs) with preserved cytoskeleton and demembranated CCMs, consisting only of cytoskeletal elements, were used to examine the relationship of pericanalicular microfilaments, myosin II phosphorylation, and canalicular contraction. The components of CCMs were visualized by fluorescence microscopy using the filamentous actin probe rhodamine-phalloidin and by electron microscopy, before and after incubation in 1 microM Ca2+/1 mM ATP (contraction solution). Canalicular contraction (luminal closure) was evaluated by morphometric analysis. Myosin II was extracted from CCMs, purified by immunoprecipitation, and analyzed on Western blots. In sequential experiments, autoradiographs of gels from [gamma-32P]-ATP-treated CCMs in the presence or absence of Ca2+ were examined after 0.25, 0.50, 1, 2, 3, 5, and 10 min, and the effects of W7 (a calmodulin antagonist) and ML9 (a myosin light chain kinase inhibitor) were evaluated. The results showed that phosphorylation of the 20-kDa protein was low in controls but enhanced beginning 0.25-0.50 min after addition of contraction solution. Both W7 and ML9 significantly inhibited this reaction and inhibited canalicular contraction. The results indicate that phosphorylation of the regulatory 20-kDa myosin light chain of canaliculus-associated myosin II coincides with or precedes contraction of the canaliculus. We conclude that the canalicular contractile apparatus is composed of actin filaments and a myosin II motor.

Actins↗
PubMed1994

Expression of Fc epsilon R2/CD23 and p55 IL-2R/CD25 on peripheral blood macrophages/monocytes in multiple sclerosis.

Macrophages have been found histologically to be activated in multiple sclerosis. We analyzed the expression of CD23 and CD25 on monocytes/macrophages in peripheral blood obtained from patients with multiple sclerosis (MS) to investigate their role in the demyelinating process. Peripheral blood mononuclear cells were obtained from 30 patients with MS including four Baló's diseases (24 with acute relapsing type disease, six with chronic progressive type disease) and 12 healthy controls. The percentage of CD14+CD23+ monocytes/macrophages and CD14+CD25+ monocytes/macrophages were determined by two-color flow cytometry. The percentage of CD14+CD23+ monocytes was significantly higher in patients with MS in the active phase as compared with controls (P < 0.01). Six patients with acute relapsing MS, who had received no therapy, had higher CD14+CD23+ cells than did controls (P < 0.0001). CD14+CD25+ monocytes/macrophages were not detected in peripheral blood monocytes/macrophages of patients with MS except Baló's concentric sclerosis. The four patients with Baló's concentric sclerosis had markedly elevated levels of CD14+CD25+ monocytes/macrophages. Our findings suggest that monocytes/macrophages are activated during an exacerbation of MS, and that they may play an important role in the process of demyelination.

Adult↗
PubMed1994

Increased levels of soluble tumor necrosis factor receptor in patients with multiple sclerosis and HTLV-1-associated myelopathy.

Tumor necrosis factor-alpha (TNF-alpha) is a potent mediator produced by activated T lymphocytes and macrophages, which may play a role in the pathogenesis and development of multiple sclerosis (MS) and HTLV-1-associated myelopathy (HAM). The first step in the induction of many biological effects elicited by TNF-alpha is its binding to specific cell surface receptors. A soluble form of TNF receptor (sTNF-R) can be detected in the body fluid. We measured sTNF-R levels in the sera and cerebrospinal fluid (CSF) of patients with either MS or HAM, and evaluated the correlation between this mediator and disease activity. The levels of sTNF-R in the sera and CSF of patients with MS were significantly increased compared with controls, particularly patients with acute relapsing MS during an exacerbation (P < 0.001). CSF levels of sTNF-R showed a strong correlation with those of TNF (r = 0.716, P < 0.001). Higher levels of sTNF-R in the sera of HAM patients were detected as compared with those of either controls (P < 0.001) or non-HAM carriers (P < 0.001). Patients with HAM exhibited significantly higher CSF levels of sTNF-R than those with other neurological diseases (P < 0.0001). These results suggest that the detection of sTNF-R in the sera and CSF may predict disease progression. Availability of such a marker would be useful in monitoring disease activity.

Adult↗
PubMed1994

In vitro intercellular adhesion molecule-1 expression on brain endothelial cells in multiple sclerosis.

To investigate the origin of intercellular adhesion molecule-1 (ICAM-1) and its expression on brain endothelial cells, we studied the expression in vitro of ICAM-1 on human brain endothelial cells after incubation of T cells from patients with multiple sclerosis (MS) using a histochemical technique and flow cytometry. We determined soluble forms of ICAM-1 (ICAM-1) in the supernatants after mixtures of brain endothelial cells and T cells from patients with MS using an enzyme-liked immunosorbent assay. Flow cytometric analysis showed that a number of ICAM-1-positive cells were significantly increased after incubation of brain endothelial cells with T cells from patients with acute relapsing MS during an exacerbation as compared with those of controls (P < 0.01). Patients with acute relapsing MS during an exacerbation and chronic progressive MS exhibited higher levels of ICAM-1 in the supernatants of mixtures with brain endothelial cells and lymphocytes than those of controls (P < 0.001 and P < 0.01, respectively). These results suggest that lymphocytes from patients with acute relapsing MS during an exacerbation lead to an increased expression of ICAM-1 on the brain endothelial cells and add to evidence involving this adhesion molecule in the pathogenesis of MS.

Adult↗
PubMed1994

Evidence of direct interaction between Kupffer cells and colon cancer cells: an ultrastructural study of the co-culture.

A co-culture study of purified rat Kupffer cells and human colon cancer cells was performed, and the process of the tumor cell injury was observed under an inverted type fluorescence microscope loaded with propidium iodide, and also under an electron microscope. Ultrastructurally there was direct membrane-to-membrane interaction between Kupffer cells and colon cancer cells in time. The interaction occurred 1 h after start of the co-culture, and injured tumor cells were observed closely attached to pseudopodia of Kupffer cells at 6 h. The number of propidium iodide-positive tumor cells with damage increased in time. Pretreatment with NG-monomethyl-L-arginine reduced the number of injured tumor cells without preventing morphological interactions, but superoxide dismutase did not prevent the tumoricidal effect. Pretreatment with trypsin completely inhibited cell interaction and damage to tumor cells. In conclusion, the morphological interaction of Kupffer cells as a first step and the involvement of nitric oxide-derived free radicals as a second step seem to play a significant role in the host-defense mechanism.

Animals↗
PubMed1994

Expression of intercellular adhesion molecule-1 and lymphocyte function-associated antigen-1 in the spinal cord of rats during acute experimental allergic encephalomyelitis.

We investigated the expression of intercellular adhesion molecule-1 (ICAM-1) and lymphocyte function-associated antigen-1 (LFA-1) by cells in the central nervous system (CNS) of Lewis rats during acute experimental allergic encephalomyelitis (EAE). A few endothelial cells in the CNS of normal rats expressed ICAM-1, whereas during the active phase of EAE, ICAM-1 was present on many endothelial cells. This alteration was detectable the day before clinical symptoms. Since histopathological studies showed few detectable mononuclear cells or inflammatory foci in any section of the preclinical rats, the expression of ICMA-1 was considered to be important at least in the early stage of inflammation. LFA-1 was seen on perivascular infiltrating cells. An increase in either ICAM-1- or LFA-1-positive cells was initially seen in the lumbosacral portion of the spinal cord, which then extended to the thoracic portion. The number of either ICAM-1- or LFA-1-positive cells peaked on the day of clinical onset in the lumbosacral portion. In contrast, in the thoracic portion, a peak in the number of either ICAM-1- or LFA-1-positive cells was observed on the day after clinical onset. This ascending extension of either ICAM-1- or LFA-1-positive cells was correlated with the progression of neurologic signs. It is suggested that increased expression of ICAM-1 and LFA-1 in the CNS of rat EAE may promote the extravasation of lymphocytes across the blood-brain barrier and be related to progression of the disease.

Acute Disease↗
PubMed1994

Adhesion and cytotoxicity of myelin basic protein-specific encephalitogenic T cells to normal and inflamed cerebral endothelial cells.

To study the mechanisms involved in the pathogenesis of the blood-brain barrier (BBB) breakdown in autoimmune demyelinating diseases, such as experimental allergic encephalomyelitis (EAE), we investigated the cell interaction in vitro between myelin basic protein (MBP)-specific encephalitogenic T cells and normal and inflamed cerebral endothelial cells, and the cytotoxic effect of antigen specific T cell lines on normal and inflamed cerebral endothelial cells. The importance of relationship between cell surface adhesion and cytotoxic T lymphocyte (CTL) was examined by monoclonal antibodies (mAb) against adhesion receptors. The adhesion of encephalitogenic T cells to inflamed endothelial cells was significantly increased as compared with normal endothelial cells (P < 0.001). The percentage lysis of inflamed endothelial target cells was significantly increased by incubation with MBP-encephalitogenic T cell lines in the presence of MBP as compared with those of normal endothelial targets (P < 0.0001). Intercellular adhesion molecule-1 (ICAM-1) is not involved in T cell adhesion to endothelial cells or cytotoxic endothelial cell lysis. Antibodies against human alpha 4 integrin (HP 2/1) and beta 1 (A11B2) inhibited T cell adhesion, but did not block cytotoxic endothelial cell lysis. These results indicate that T cell adhesion to inflamed cerebral endothelial cells and cytotoxicity of T cells for cerebral endothelial cells may play a central role in the breakdown of the BBB and development of inflammatory lesions in the central nervous system(CNS).

Animals↗
PubMed1994

[Age-related changes of B-cell immune function in patients with subacute myelo-optico-neuropathy (SMON)].

Several kinds of immunological abnormalities have been found more frequently in patients with subacute myelo-optico-neuropathy (SMON). To investigate whether the B-cell immune system is implicated in aging in patients with SMON, we examined serum levels of immunoglobulin including IgG, IgM, and IgA, and the number of CD20+ cells (B lymphocytes) and CD20+ CD23+ cells (activated B lymphocytes) using flow cytometry, and compared them with those in age-matched controls. We also investigated whether the number of HLA-DR+ cells was correlated with those of CD20+ cells, CD20+ CD23+ cells, or HLA-DR+CD3+ cells (activated T lymphocytes) in patients with SMON. Serum levels of IgG, IgM and IgA were decreased with aging both in the patients with SMON and in the controls, and no significant difference was found between the two groups. Although the patients with SMON tended to show higher levels of CD20+ and CD20+ CD23+ cells than the age-matched controls, there were no significant differences between the two groups. The number of HLA-DR+ cells was correlated not with that of CD20+ cells or CD20+ CD23+ cells, but with that of HLA-DR+CD3+ cells. In patients with SMON, it is likely that the B-cell immune system is mainly implicated in the effect of aging, but it is unlikely that other factors than aging are associated with the B-cell immune system. The increase in the number of HLA-DR+ cells associated with aging in patients with SMON reflects the increase in the number of activated T lymphocytes, and is not correlated with the changes of B lymphocytes.

Age Factors↗