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Biomedical subjects

A Nakao

Publications and source records attributed to A Nakao.

At least 37 records · Page 2Linked to original sources
PubMed2003

Smads regulate collagen gel contraction by human dermal fibroblasts.

BACKGROUND: Transforming growth factor (TGF)-beta induces fibroblast contraction that is implicated in efficient wound healing. The Smad family of proteins mediates signal transduction of the TGF-beta superfamily. However, its role in fibroblast contraction remains unclear. OBJECTIVES: To determine whether Smad proteins regulate fibroblast contraction. METHODS: We used an in vitro type I collagen gel contraction assay with human dermal fibroblasts infected with adenoviruses carrying Smads. RESULTS: Overexpression of Smad3, a major signal transducer in the Smad family, enhanced collagen gel contraction by fibroblasts when compared with fibroblasts overexpressing a control lacZ. Addition of a very low concentration of TGF-beta1 that did not affect the collagen gel contraction by itself enhanced the contraction by fibroblasts overexpressing Smad3. In contrast, TGF-beta1-mediated collagen gel contraction was suppressed by overexpression of Smad7, a major inhibitory regulator in the Smad family, in fibroblasts. In addition, inhibitors of the Erk and p38 pathways, PD98059 and SB203580, did not affect TGF-beta1-mediated collagen gel contraction by dermal fibroblasts. CONCLUSIONS: Modulation of Smad3 or Smad7 expression in dermal fibroblasts affected their contraction of collagen gels possibly by regulating TGF-beta signalling in fibroblasts.

Blotting, Western↗
PubMed2003

Immunomodulatory effects of inhaled carbon monoxide on rat syngeneic small bowel graft motility.

BACKGROUND: Intestinal transplantation provokes an intense inflammatory response within the graft muscularis that causes intestinal ileus. We hypothesised that endogenously produced anti-inflammatory substances could be utilised as novel therapeutics. Therefore, we tested the protective effects of inhaled carbon monoxide (CO) and an endogenous haeme oxygenase 1 (HO-1) anti-inflammatory mediator on transplant induced inflammatory responses and intestinal ileus in the rat. METHODS: Gastrointestinal transit of non-absorbable FITC labelled dextran and in vitro jejunal circular muscle contractions were measured in controls and syngeneic orthotopic transplanted animals with and without CO inhalation (250 ppm for 25 hours). Inflammatory mRNAs for interleukin (IL)-6, IL-1beta, tumour necrosis factor alpha (TNF-alpha), intercellular adhesion molecule 1 (ICAM-1), inducible nitric oxide (iNOS), cyclooxygenase 2 (COX-2), and IL-10 were quantified by real time reverse transcriptase-polymerase chain reaction and HO-1 by northern blot. Histochemical stains characterised neutrophil infiltration and enterocyte apoptosis. RESULTS: Transplantation delayed transit and suppressed jejunal circular muscle contractility. Transplantation induced dysmotility was significantly improved by CO inhalation. Transplantation initiated a significant upregulation in IL-6, IL-1beta, TNF-alpha, ICAM-1, iNOS, COX-2, and HO-1 mRNAs with the graft muscularis. CO inhalation significantly decreased expression of IL-6, IL-1beta, iNOS, and COX-2 mRNAs. CO also significantly decreased serum nitrite levels (iNOS activity). CONCLUSIONS: CO inhalation significantly improved post-transplant motility and attenuated the inflammatory cytokine milieu in the syngeneic rat transplant model. Thus clinically providing CO, the end product of the anti-inflammatory HO-1 pathway, may prove to be an effective therapeutic adjunct for clinical small bowel transplantation.

Animals↗
PubMed2002

ABO-incompatible auxiliary partial orthotopic liver transplant for late-onset familial amyloid polyneuropathy.

A 60-year-old Japanese man with late-onset familial amyloid polyneuropathy type I (FAP transthyretin Met30) showed clinical improvement following auxiliary partial orthotopic liver transplantation (APOLT) from an ABO-incompatible living related donor. Preoperatively, plasmapheresis and immunosuppressant drugs were used to reduce serum antibodies against the donor's ABO type. APOLT was chosen so the residual liver could sustain the patient in the event of hyperacute rejection. OLT is applicable to late-onset FAP transthyretin Met30, and APOLT can be considered in ABO-incompatible cases.

ABO Blood-Group System↗
PubMed2002

Laparoscopic bilateral adrenalectomy for Cushing's syndrome due to ACTH-independent macronodular adrenocortical hyperplasia.

We performed simultaneous bilateral laparoscopic total adrenalectomy in two patients with Cushing's syndrome due to ACTH-independent macronodular adrenocortical hyperplasia (AIMAH). Preoperative serum cortisol in the patients was 29.5 and 53.2 microg/dl, respectively. The clinical symptoms of the latter patient were advanced, and respiration was labored with orthopnea. Laparoscopic adrenalectomies were performed transabdominally in the sequential lateral decubitus positions with extension of the lateral abdominal wall of the affected side. Three 12-mm and three 5-mm trocars were positioned, and two trocar sites in the midline were used on both sides. The flexible fiberscope was inserted through the umbilical port. The adrenal glands were large, fragile, and multinodular. The maximal diameters of the removed glands were 7.8 and 8.7 cm, respectively. In both patients, the adrenal glands were successfully removed without fragmentation. The operation times were 505 and 320 min, and the estimated blood loss was 150 and 5 ml, respectively. Neither intraoperative nor postoperative complications occurred, although the latter patient required muscle training before ambulation on postoperative day 42. The procedures resulted in marked clinical improvements. Compliance with the substitutive therapy remained excellent, and the patients expressed a very high degree of satisfaction with the laparoscopic adrenal surgery. The procedures of bilateral laparoscopic adrenalectomy were successful, and provided increased experience with the laparoscopic techniques.

Adrenal Glands↗
PubMed2002

Transforming growth factor-beta1 suppresses atopic dermatitis-like skin lesions in NC/Nga mice.

BACKGROUND: Atopic dermatitis is a chronic, relapsing inflammatory disorder characterized by pruritic and eczematous skin lesions. Transforming growth factor (TGF)-beta1 has been implicated in the suppression of inflammatory responses. OBJECTIVE: The purpose of this study is to determine whether TGF-beta1 suppresses skin lesions in a mouse model of atopic dermatitis. METHODS: We used the NC/Nga strain of mice as an in vivo model of atopic dermatitis. The effects of exogenous TGF-beta1 on atopic dermatitis-like skin lesions in NC/Nga mice were evaluated clinically, histologically and immunologically. RESULTS: Subcutaneous injection of recombinant TGF-beta1 macroscopically suppressed eczematous skin lesions in NC/Nga mice associated with reduced serum immunoglobulin E (IgE) levels. Histological analysis showed that TGF-beta1 significantly inhibited the infiltration of inflammatory cells such as mast cells and eosinophils into the skin of NC/Nga mice. Spontaneous interferon (IFN)-gamma production from splenocytes of NC/Nga mice was down-regulated by the treatment with TGF-beta1 and neutralizing antibody against IFN-gamma inhibited skin lesions in NC/Nga mice. The inhibitory effect of TGF-beta1 on the skin lesions lasted at least 1 week after cessation of the treatment. CONCLUSION: These findings indicate that TGF-beta1 suppressed atopic dermatitis-like skin lesions in NC/Nga mice at least in part through down-regulation of IFN-gamma. These results suggest that TGF-beta1 may have a therapeutic potential for atopic dermatitis.

Animals↗
PubMed2001

Detection of mitochondrial DNA alterations in primary tumors and corresponding serum of colorectal cancer patients.

We previously examined colorectal cancer patients using mutation-specific mismatch ligation assay for genetic alterations in primary tumors and paired serum samples and proved that genetic alterations present in the tumors of cancer patients can be detected in the serum of those same patients. Recent evidence has proved that various cancers frequently have mutations in the D-loop region of mitochondrial DNA (mtDNA). Therefore, we thought that mutations in the mitochondrial genome might also become a genetic marker of colorectal cancer to detect tumor DNA in the serum of patients. We first sequenced the D-loop region of mtDNA in colorectal cancers. We then proceeded with a sensitive method, i.e., mismatch ligation assay to examine the possibility that mtDNA alterations can be found in the serum DNA. We analyzed the D-loop region of mtDNA in 77 primary colorectal cancers, 7 of which (9%) contained true somatic mutations in this region. We then examined whether mtDNA alterations can be found in the serum DNA using mismatch ligation assay. Of 7 alterations that were examined, 1 (14%) could be detected in the serum. This result suggested that the mtDNA alteration could also be used as a tumor marker to detect tumor DNA in the serum.

Base Pair Mismatch↗
PubMed2001

Identification of Nash1, a novel protein containing a nuclear localization signal, a sterile alpha motif, and an SH3 domain preferentially expressed in mast cells.

By using a serial analysis of gene expression (SAGE), we have identified a novel full-length cDNA that is preferentially expressed in human cord blood-derived mast cells. The predicted protein showed unique primary structure with a nuclear localization signal (NLS), a sterile alpha motif (SAM), and a Src homology 3 domain (SH3) (termed Nash1). Nash1 was mapped to human chromosome 21q11.1 and highly expressed in spleen, liver, peripheral blood, and mast cell lines. In consistent with the presence of NLS, Nash1 was localized in the nucleus. Interestingly, screening gene databases for Nash1-related sequences revealed the existence of a Nash1-related gene termed SLY that was preferentially detected in lymphoid cells. We also found at least two additional candidates for this gene family in the database. These findings suggested that Nash1 and Nash1-related proteins consisted of a novel family of signaling/adaptor proteins, and Nash1 might function as a signaling component of mast cells, possibly in the nucleus.

Adaptor Proteins, Vesicular Transport↗
PubMed2001

Puromycin aminonucleoside induces apoptosis and increases HNE in cultured glomerular epithelial cells(1).

Puromycin aminonucleoside induces apoptosis and increases 4-hydroxy-2-nonenal (HNE) in cultured glomerular epithelial cells. We have previously reported the detachment of cultured glomerular epithelial cells (GECs) from their substrata by puromycin aminonucleoside (PAN) treatment. In this study we explored whether or not apoptosis was involved in the mechanisms of the detachment. DNA fragmentation on gel electrophoresis was clearly shown by 10(-3) M PAN treatment of GECs. Nuclear staining by Hoechst 33342 indicated the greatest number of apoptotic cells at 10(-3) M PAN for 48 h treatment. Similarly, TUNEL methods revealed maximal apoptotic cells at 10(-3) M PAN for 48 h treatment. Caspase-3 (like) protease activity increased at 10(-3) M PAN, and decreased at 2 x 10(-3) M PAN for 48 h treatment as well as at 10(-3) M PAN for 60 h treatment. Pretreatment with 2'-deoxycoformycin (DCF), inhibitor of adenosine deaminase, abolished these effects of PAN on cultured GECs. PAN treatment increased HNE, a lipid peroxide adduct, modified protein in cultured GECs, which was also prevented by pretreatment by DCF. These results for the first time indicate that the PAN-induced detachment of GECs from culture substrata is mediated at least in part through apoptosis via oxidative stresses by adenosine deaminase activity.

Adenosine Deaminase Inhibitors↗
PubMed2001

Impairment of bleomycin-induced lung fibrosis in CD28-deficient mice.

Lung fibrosis is an important pulmonary disease with a high mortality rate, but its pathophysiological mechanism has not been fully clarified. Various types of cells have been implicated in the development of lung fibrosis, including T cells. However, the contribution of functional molecules expressed on T cells to the development of lung fibrosis remains largely unknown. In this study, we determined whether costimulation via CD28 on T cells was crucial for the development of lung fibrosis by intratracheally administering bleomycin into CD28-deficient mice. Compared with wild-type mice, the CD28-deficient mice showed markedly impaired lung fibrosis after injection with low doses of bleomycin, as judged by histological changes and hydroxyproline content in the lungs. In addition, bleomycin-induced T cell infiltration into the airways and production of several cytokines and chemokines including IL-5 were also impaired in the CD28-deficient mice. Furthermore, adoptive transfer of CD28-positive T cells from wild-type mice recovered the impaired bleomycin-induced lung fibrosis in CD28-deficient mice. These findings suggest that the CD28-mediated T cell costimulation plays a critical role in the development of lung fibrosis, possibly by regulating the production of cytokines and chemokines in the lung. Thus, manipulation of the CD28-mediated costimulation could be a potential therapeutic strategy for the prevention of lung fibrosis.

Adoptive Transfer↗
PubMed2001

Protective roles of mast cells against enterobacterial infection are mediated by Toll-like receptor 4.

Toll-like receptors (TLRs) are mammalian homologues of the Drosophila Toll receptors and are thought to have roles in innate recognition of bacteria. We demonstrated that TLR 2, 4, 6, and 8 but not TLR5 were expressed on mouse bone marrow-derived mast cells (BMMCs). Using BMMCs from the genetically TLR4-mutated strain C3H/HeJ, we demonstrated that functional TLR4 was required for a full responsiveness of BMMCs to produce inflammatory cytokines (IL-1beta, TNF-alpha, IL-6, and IL-13) by LPS stimulation. TLR4-mediated stimulation of mast cells by LPS was followed by activation of NF-kappaB but not by stress-activated protein kinase/c-Jun NH2-terminal kinase signaling. In addition, in the cecal ligation and puncture-induced acute septic peritonitis model, we demonstrated that genetically mast cell-deficient W/W(v) mice that were reconstituted with TLR4-mutated BMMCs had significantly higher mortality than W/W(v) mice reconstituted with TLR4-intact BMMCs. Higher mortality of TLR4-mutated BMMC-reconstituted W/W(v) mice was well correlated with defective neutrophil recruitment and production of proinflammatory cytokines in the peritoneal cavity. Taken together, these observations provide definitive evidence that mast cells play important roles in exerting the innate immunity by releasing inflammatory cytokines and recruitment of neutrophils after recognition of enterobacteria through TLR4 on mast cells.

Acute Disease↗
PubMed2001

Real-time observation of micrometastasis formation in the living mouse liver using a green fluorescent protein gene-tagged rat tongue carcinoma cell line.

Initial arrest, attachment, extravasation and subsequent extravascular growth of tumor cells in the secondary organs are believed to be crucial events for hematogenous metastasis, but the actual processes in living animals remain unclear. For the present study, we established green fluorescent protein (GFP)-expressing rat tongue carcinoma cell lines (RSC3) that permit real-time analysis of micrometastasis formation in combination with intravital video microscopy (IVVM). With this system, GFP-expressing metastatic (LM-EGFP) and non-metastatic (E2-EGFP) cell lines could be visualized at the cellular level in live mice for more than 1 month. Real-time IVVM analysis of liver metastases after intraportal injection of cells via a mesenteric vein revealed that both LM-EGFP and E2-EGFP tumor cells arrest similarly in sinusoidal vessels near terminal portal venules within 0.4 sec, during which time no evidence of a "rolling"-like movement along endothelial cell surfaces was observed. Quantitative analysis of GFP-positive foci showed that E2-EGFP cells were completely sheared from the liver sinusoid within 3 days, with no solitary dormant cells, whereas a substantial number of LM-EGFP cells remained in the liver, probably due to stable attachment to the sinusoidal wall. Confocal laser scanning microscopic study in combination with laminin immunohistochemistry revealed that only LM-EGFP cells started growth at 3 to 4 days after inoculation and that most of the growing foci were surrounded by subsinusoidal basement membrane. Our results suggest that micrometastasis formation by LM-EGFP cells consists of initial tumor cell arrest due to size constraints of the vessel, stable attachment to subsinusoidal basement membrane and subsequent intravascular growth before extravasation. The difference in metastatic potential between the 2 lines may reside in their capacity to attach stably to the vessel wall rather than their potential for initial cell arrest or subsequent growth. The system used in the present study may be a powerful tool for analyzing targets for various anti-metastatic agents in the sequential process of metastasis.

Animals↗