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Biomedical subjects

N Tsukada

Publications and source records attributed to N Tsukada.

At least 19 recordsLinked to original sources

The out-patient management of patients with acute mild-to-moderate colonic diverticulitis.

BACKGROUND: There are no management criteria for optimum out-patient care in mild-to-moderate acute colonic diverticulitis. AIM: To enable such patients to be managed in an out-patient setting, by establishing criteria and treatment protocols. METHODS: We conducted an open trial and follow-up study from 1997 to 2002. On the basis of ultrasonography, we defined and categorized mild-to-moderate acute colonic diverticulitis ranging from limited inflammation within diverticulum to an abscess < 2 cm in diameter. Subjects were treated as out-patients and followed a 10-day treatment protocol consisting of an oral antibiotic and a sports drink for the first 3 days. Physical examination and laboratory testing helped determine whether or not a patient could resume a liquid diet on day 4, and a regular diet on day 7. RESULTS: Of the 70 patients, 68 were successfully treated. Two patients required hospitalization. Of the 65 patients who were tracked over several months [median (intraquarter range) = 30.8 (11.9-44.2) months], 16 had one or more clinical recurrences. The medical cost per episode was 80% lower than in-patient treatment. CONCLUSIONS: Patients with mild-to-moderate acute colonic diverticulitis can be safely and successfully treated as out-patients using this protocol.

Acute Disease↗

Effect of prostaglandin E2, lipopolysaccharide, IFN-gamma and cytokines on the generation and function of fast-DC.

BACKGROUND: Recent reports have described a new strategy for differentiation and maturation of monocyte-derived DC within only 48 h of in vitro culture (fast-DC). We compared the ability of various maturation stimuli with the generation of Ag-specific T-cell responses and generation of functional fast-DC. METHODS: CD14+ cells were treated with GM-CSF and IL-4 for 1 day to generate immature DC, and were then matured with either inflammatory cytokines or a combination of lipopolysaccharide (LPS) and INF-gamma. Mature DC were then used to study the effect of prostaglandin E2 (PGE2) on the stimulatory function of fast-DC. RESULTS: fast-DC were CD14- and expressed mature DC surface markers, and maintained this phenotype after withdrawing the cytokine from culture. Treatment of fast-DC with a combination of LPS and INF-gamma promoted the maturation of highly uniform fast-DC. The T-cell proliferative response to DC was enhanced by inclusion of PGE2 in the MCM-mimic (TNF-a, IL-1 a, IL-6, PGE2) cocktail. DISCUSSION: fast-DC are very effective; they not only reduce the labor, cost and time required for in vitro DC development, but may also represent a model more closely resembling DC differentiation from monocytes in vivo.

Antineoplastic Agents↗

Bile canalicular contraction and dilatation in primary culture of rat hepatocytes--possible involvement of two different types of plasma membrane Ca(2+)-Mg(2+)-ATPase and Ca(2+)-pump-ATPase.

Increasing evidence has indicated that bile canalicular contraction is mediated by the nonmuscular Ca(2+)-calmodulin-actomyosin system, and the contraction facilitates canalicular bile flow. The aim of the present study was to examine, by electron cytochemistry, how the expression of two types of plasma membrane Ca(2+)-ATPase, i.e., Ca(2+)-Mg(2+)-ATPase and Ca(2+)-pump-ATPase, is related to the dynamic changes of bile canalicular contraction. Hepatocytes isolated from male Wistar rat liver by collagenase perfusion were cultured to form a primary monolayer. The canalicular dynamics in the couplets and triplets were analyzed by time-lapse cinematography. The Ca(2+)-Mg(2+)-ATPase activity was identified by the electron cytochemical method of Ando. Ultrastructural localization of Ca(2+)-pump-ATPase was examined by immunogold electron microscopy. We found that cytochemical reaction products showing the presence of Ca(2+)-Mg(2+)-ATPase activity were localized on the luminal side of the bile canalicular membranes. Immunogold particles, indicating the presence of Ca(2+)-pump-ATPase, were located mainly on the cytoplasmic side of the bile canalicular membranes. The expression of both Ca(2+)-ATPases on the canalicular membranes was enhanced during the contracting stage of bile canaliculi, whereas their expression was diminished in the dilating stage. We conclude that two different types of bile canalicular Ca(2+)-ATPase may be involved in the regulation of canalicular contractility to control the extrusion of intracytoplasmic free calcium ions into the canalicular lumen.

Animals↗

Th1 and Th2 cytokines differentially regulate the transformation of Kupffer cells into multinucleated giant cells but similarly enhance the Kupffer cell-induced hepatic stellate cell proliferation.

To investigate the effects of T-helper cytokines on Kupffer cells (KCs), the effects of interferon-gamma (IFN-gamma; Th1 cytokine) and interleukin-4 (IL-4; Th2 cytokine) on KC morphology and their role in modulating the growth of hepatic stellate cells (HSCs) were examined. Fluorescence microscopic and electron microscopic data demonstrated that IL-4 transforms rat KCs into multinucleated giant cells (MGCs) in vitro. This transformation was inhibited by the addition of anti-ICAM-1 and anti-CD18 monoclonal antibodies. In addition, IL-4-induced KC transformation was suppressed by the presence of IFN-gamma. The formation of mouse hepatic MGCs was also demonstrated in vivo by the intraperitoneal injection of recombinant mouse IL-4. Although the presence of MGCs was found in all five out of five livers from IL-4-treated Th2-dominant BALB/c mice, but it was in only two out of five livers from IL-4-treated Th1-dominant C57BL/6 mice. In addition, fewer MGCs were found in the liver of C57BL/6 mice. In contrast, IFN-gamma treatment did not form hepatic MGCs in mice at all. The growth of HSCs in vitro was significantly increased by the addition of culture supernatant from lipopolysaccharide-stimulated rat KCs. Pretreatment of the KCs with either IFN-gamma or IL-4 further enhanced the growth stimulation. These results suggest that IFN-gamma and IL-4 affect KC morphology differently, but that both Th1 and Th2 cytokines play a similar role in the modulation of HSC growth by Kupffer cells in the presence of lipopolysaccharide.

Journal Article↗

Enhanced expression of endothelin receptor subtypes in cirrhotic rat liver.

BACKGROUND/AIMS: A number of vasoactive substances have been implicated as potential mediators of intrahepatic portal hypertension. Endothelin (ET)-1 has been suggested to be involved in the regulation of hepatic microcirculation and development of portal hypertension. The aim of this study was to clarify the localization of two subtypes of ET receptors, ET A (ETAR) and B receptors (ETBR), in normal rat liver, and how the receptor expressions are altered in CCl4-induced cirrhotic rat liver. METHODS: Liver specimens were examined immunohistochemically after reacting with anti-ETAR and anti-ETBR rabbit polyclonal antibodies. Immunogold staining was also performed using the same antibodies, and examined under light and electron microscopy. RESULTS: In normal rat liver, immunohistochemistry revealed expression of ETAR and ETBR on the hepatic sinusoidal lining cells. By immunogold electron microscopy, electron-dense gold particles indicating the presence of ETARs were localized mainly on hepatic stellate cells (HSCs) and to a lesser extent on sinusoidal endothelial cells (SECs), while ETBRs were expressed equally intensely on HSCs and SECs. In cirrhotic animals, both ETAR and ETBR increased significantly on HSCs, while there were no significant increases in either receptor on SECs. CONCLUSIONS: In the normal state, HSCs possess both ETARs and ETBRs, while SECs mainly possess ETBRs. In cirrhosis, endothelins may exert more intense effects on HSCs via the enhanced ETARs and ETBRs, causing an increase in hepatic sinusoidal microvascular tone.

Animals↗

Endothelial nitric oxide synthase and caveolin-1 are co-localized in sinusoidal endothelial fenestrae.

BACKGROUND/AIMS: Nitric oxide is synthesized in diverse mammalian tissues by a family of calmodulin-dependent nitric oxide synthases (NOS). Caveolin, the principal structural protein in caveolae, interacts with endothelial NOS leading to enzyme inhibition in a reversible process modulated by Ca++-calmodulin. The aim of the present study was to clarify the ultrastructural localization of eNOS and caveolin-1 in hepatic sinusoidal endothelium by an electron immunogold method. METHODS: Male Wistar rats were used. Liver tissues and hepatic sinusoidal endothelial cells isolated from rat livers by collagenase infusion were studied. For immunohistochemistry, liver specimens were reacted with anti-eNOS or anti-caveolin-1 antibody. The ultrastructural localization of eNOS or caveolin-1 was identified by electron microscopy using an immunogold post-embedding method. RESULTS: Immunohistochemical studies using liver tissues localized endothelial NOS in hepatic sinusoidal lining cells, portal veins and hepatic arteries; and caveolin-1 in sinusoidal lining cells, bile canaliculi, portal vein and hepatic arteries. Immunogold particles indicating the presence of eNOS and caveolin-1 were demonstrated on the plasma membrane of sinusoidal endothelial fenestrae in liver tissue and also in isolated sinusoidal endothelial cells. CONCLUSION: Endothelial NOS and caveolin are co-localized on sinusoidal endothelial fenestrae, suggesting that interaction of the two may modulate cellular regulation of NO synthesis.

Animals↗

Fibroblast-like synoviocytes support B-cell pseudoemperipolesis via a stromal cell-derived factor-1- and CD106 (VCAM-1)-dependent mechanism.

B-cell accumulation and formation of ectopic germinal centers are characteristic changes in the diseased joints of patients with rheumatoid arthritis (RA). Earlier studies suggested that interactions between B lymphocytes and specialized synovial "nurse-like" cells peculiar to the RA synovium may be responsible for the homing and sustained survival of B cells in the synovium. However, in this study, we found that B cells spontaneously migrate beneath ordinary fibroblast-like synoviocytes (FLSs) and then experience prolonged survival. FLSs isolated from joints of patients with osteoarthritis also supported this activity, termed B-cell pseudoemperipolesis. We found that FLSs constitutively expressed the chemokine stromal cell-derived factor-1 (SDF-1), and that pertussis toxin or antibodies to the SDF-1 receptor (CXCR4) could inhibit B-cell pseudoemperipolesis. However, expression of SDF-1 is not sufficient, as dermal fibroblasts also expressed this chemokine but were unable to support B-cell pseudoemperipolesis unless previously stimulated with IL-4 to express CD106 (VCAM-1), a ligand for the alpha(4)beta(1) integrin, very-late-antigen-4 (VLA-4 or CD49d). Furthermore, mAb's specific for CD49d and CD106, or the synthetic CS1 fibronectin peptide, could inhibit B-cell pseudoemperipolesis. We conclude that ordinary FLSs can support B-cell pseudoemperipolesis via a mechanism dependent upon fibroblast expression of SDF-1 and CD106.

Arthritis, Rheumatoid↗

Primary adenosquamous carcinoma of the liver which produces granulocyte-colony-stimulating factor and parathyroid hormone related protein: association with leukocytosis and hypercalcemia.

A 55-year-old man was admitted to our hospital with fever and vomiting. Abdominal computed tomography (CT) revealed multiple low density masses in the liver. A diagnosis of primary adenosquamous carcinoma of the liver was confirmed by histological examination of a necropsy specimen. The present case showed leukocytosis and hypercalcemia with high levels of serum granulocyte-colony-stimulating factor (G-CSF) and parathyroid hormone related protein (PTHrP). Recent studies have shown that G-CSF and PTHrP are responsible for the paraneoplastic syndromes with leukocytosis and hypercalcemia. The tumor cells demonstrated positive cytoplasmic immunohistochemistry staining with anti-G-CSF and anti-PTHrP antibodies. This result suggested that the tumor produced G-CSF and PTHrP.

Carcinoma, Adenosquamous↗

Blood-derived nurse-like cells protect chronic lymphocytic leukemia B cells from spontaneous apoptosis through stromal cell-derived factor-1.

A subset of blood cells from patients with B-cell chronic lymphocytic leukemia (CLL) spontaneously differentiates in vitro into large, round, or fibroblast-like adherent cells that display stromal cell markers, namely vimentin and STRO-1. These cells also express stromal cell-derived factor-1 (SDF-1), a CXC chemokine that ordinarily is secreted by marrow stromal cells. Leukemia B cells attach to these blood-derived adherent cells, down-modulate their receptors for SDF-1 (CXCR4), and are protected from undergoing spontaneous apoptosis in vitro. Neutralizing antibodies to SDF-1 inhibit this effect. Moreover, the rapid deterioration in the survival of CLL B cells, when separated from such cells, is mitigated by exogenous SDF-1. This chemokine also results in the rapid down-modulation of CXCR4 and activation of p44/42 mitogen-activated protein-kinase (ERK 1/2) by CLL B cells in vitro. It is concluded that the blood of patients with CLL contains cells that can differentiate into adherent nurse-like cells that protect leukemia cells from undergoing spontaneous apoptosis through an SDF-1-dependent mechanism. In addition to its recently recognized role in CLL B-cell migration, SDF-1-mediated CLL B-cell activation has to be considered a new mechanism involved in the microenvironmental regulation of CLL B-cell survival. (Blood. 2000;96:2655-2663)

Apoptosis↗

Blockade of CD134 (OX40)-CD134L interaction ameliorates lethal acute graft-versus-host disease in a murine model of allogeneic bone marrow transplantation.

Expression of CD134 (OX40) on activated CD4(+) T cells has been observed in acute graft-versus-host disease (GVHD) after human and rat allogeneic bone marrow transplantation (BMT). We investigated the role of interaction between CD134 and CD134 ligand (CD134L) in a murine model of acute GVHD by using a newly established monoclonal antibody (mAb) against murine CD134L. Acute GVHD was induced by transfer of bone marrow cells and spleen cells into lethally irradiated recipients in a parent (C57BL/6) to first filial generation (C57BL/6 crossed with DBA/2) BMT. Administration of anti-CD134L mAb significantly reduced the lethality of acute GVHD and other manifestations of the disease, such as loss of body weight, hunched posture, diarrhea, and patchy alopecia. The survival rate 80 days after BMT in mice treated with the mAb was about 70%, whereas all mice treated with control antibodies died within 43 days. Histologic examinations revealed that inflammatory changes in target organs such as the liver, gut, and skin were also ameliorated in mice treated with the mAb compared with control mice. An in vitro assay of T-cell proliferation showed a marked hyporesponsiveness to host alloantigen in samples from mice treated with anti-CD134L mAb. In addition, low levels of interferon gamma and transiently elevated levels of interleukin 4 and IgE in serum samples were found in mice treated with anti-CD134L mAb. These results suggest that CD134-CD134L interactions have an important role in the pathogenesis of acute GVHD.

Acute Disease↗

Benzannulation from alkynes and allyl tosylates via a pi-allylpalladium intermediate

[reaction: see text] Allyl tosylate is a good allyl source for a novel palladium-catalyzed benzannulation that affords polysubstituted benzenes from 1 mol of an allyl compound and 2 mol of internal alkynes. Using triphenyl phosphite as a ligand, the reaction with terminal alkynes gave trisubstituted benzenes regioselectively.

Journal Article↗

Hepatic sinusoidal endothelial fenestrae express plasma membrane Ca++pump and Ca++Mg++-ATPase.

BACKGROUND/AIM: In general, intracytoplasmic free calcium ions (Ca++) are maintained at a very low concentration in mammalian tissue by extruding Ca++ against a high concentration of extracellular Ca++, mainly through the activity of the plasma membrane Ca++pump-ATPase. The aim of the present study was to demonstrate by electron cytochemical and immunogold methods the ultrastructural localization of two different types of plasma membrane Ca++-ATPase, i.e. Ca++Mg++-ATPase and Ca++pump-ATPase in the hepatic sinusoidal endothelium. METHODS: Liver tissues and the isolated hepatic sinusoidal endothelial cell (SEC)s were subjected to the following procedures. The ultrastructural localizations of Ca++Mg++-ATPase were examined by an electron cytochemical method. The ultrastructural localization of Ca++pump-ATPase was identified by an electron immunogold method. RESULTS: The cytochemical reaction of Ca++Mg++-ATPase was found to be localized on the outer sites of the plasma membrane of sinusoidal endothelial fenestrae (SEF). The immunogold particles indicating the presence of Ca++pump-ATPase were identified on the inner sites (cytoplasmic) of the invaginated plasma membrane of SEF CONCLUSIONS: Both Ca++Mg++-ATPase and Ca++pump-ATPase demonstrated on the SEF plasma membrane may be involved in the regulation of intracytoplasmic Ca++ concentration.

Animals↗

Cowden's disease diagnosed through mucocutaneous lesions and gastrointestinal polyposis with recurrent hematochezia, unrevealed by initial diagnosis.

A 51-year-old man was admitted to our hospital because of hematochezia and painful keratotic plaques involving both hands. He had gastrointestinal polyposis, and a history of liver hemangiomas and thyroid tumor. Numerous papules on the face and papillomatosis on the oral mucosa were present. A diagnosis was made as a typical case of Cowden's disease according to the criteria proposed by Salem and Steck (J Am Acad Dermatol 8: 686, 1983). The patient was not correctly diagnosed initially in spite of typical manifestations of Cowden's disease, mainly due to his concomitant manifestations which occurred chronologically.

Diagnostic Errors↗

Graft-versus-leukemia effect and graft-versus-host disease can be differentiated by cytotoxic mechanisms in a murine model of allogeneic bone marrow transplantation.

Allogeneic bone marrow transplantation (allo-BMT) is associated with both graft-versus-host disease (GVHD) and graft-versus-leukemia (GVL) effect. In the present study, we examined the contribution of cytotoxic effector mechanisms, which are mediated by tumor necrosis factor-alpha (TNF-alpha), Fas ligand (FasL), or perforin, to GVHD and GVL effect in a murine BMT model. Bone marrow cells plus spleen cells (BMS) from wild-type, FasL-defective, or perforin-deficient donors were transferred into lethally irradiated recipients in the parent (C57BL/6) to F1 (C57BL/6 x DBA/2) BMT model with or without prior inoculation of DBA/2 leukemia L1210 or P815 mast cytoma cells. The effect of anti-TNF-alpha antibody administration was also examined. Whereas the defect or blockade of each cytotoxic pathway could ameliorate lethal acute GVHD, the GVL effect was differentially affected. The wild-type BMS recipients died of acute GVHD within 50 days without residual leukemia cells. The FasL-defective BMS recipients showed 60%< survival over 80 days without acute GVHD or residual leukemia cells. Administration of anti-TNF-alpha antibody resulted in early leukemia relapse and the recipients died within 25 days with massive leukemia infiltration in the liver. The perforin-deficient BMS recipients died within 60 days with residual leukemia cells. These results suggest that blockade of the Fas/FasL pathway could be used for ameliorating GVHD without impairing GVL effect in allo-BMT.

Animals↗