Biomedical subjects

Hitoshi Ikeda

Publications and source records attributed to Hitoshi Ikeda.

At least 19 recordsLinked to original sources

PubMed2007

Enhanced production of p24 Gag protein in HIV-1-infected rat cells fused with uninfected human cells.

Although many human molecules have been suggested to affect replication of human immunodeficiency virus type 1 (HIV-1), the distribution of such cofactors in human cell types is not well understood. Rat W31/D4R4 fibroblasts expressing human CD4 and CXCR4 receptors were infected with HIV-1. The provirus was integrated in the host genome, but only a limited amount of p24 Gag protein was produced in the cells and culture supernatants. Here we found that p24 production was significantly increased by fusing HIV-1-infected W31/D4R4 cells with uninfected human cell lines of T-cell, B-cell, or macrophage lineages. These findings suggest that human cellular factors supporting HIV-1 replication are distributed widely in cells of lymphocyte and macrophage lineages. We also examined whether the amount of p24 produced by rat-human hybrid cells was correlated with expression levels of specific human genes. The results suggested that HP68 and MHC class II transactivator (CIITA) might up- and down-regulate p24 production, respectively. It was also suggested that HIV-1 replication is affected by molecules other than those examined in this study, namely, cyclin T1, cyclin-dependent kinase 9, CRM1, HP68, and CIITA.

Animals↗

PubMed2007

Effect of rapamycin on hepatocyte function and proliferation induced by growth factors.

BACKGROUND: Rapamycin is a specific inhibitor of the mammalian target of rapamycin (mTOR). The effect of rapamycin on proliferation and cellular function was studied in hepatocytes stimulated by hepatocyte growth factor (HGF) or transforming growth factor-alpha (TGFalpha). METHODS AND RESULTS: When isolated rat hepatocytes were cultured at low density, the addition of HGF or TGFalpha increased DNA synthesis but did not affect albumin or fibrinogen concentrations in the medium. In contrast, in hepatocytes cultured at high density, the albumin and fibrinogen concentrations, but not DNA synthesis, were increased by HGF or TGFalpha. The HGF- or TGFalpha-induced increase in DNA synthesis and in albumin or fibrinogen concentrations was suppressed by the addition of rapamycin, as well as wortmannin, a phosphatidylinositol-3 kinase inhibitor. CONCLUSION: HGF and TGFalpha stimulate proliferation and function of hepatocytes depending upon the conditions, and rapamycin inhibited these stimulatory effects, possibly by inhibiting the mTOR-dependent signaling pathway.

Albumins↗

PubMed2006

Splenic autotransplantation for a congested and enlarged wandering spleen with torsion: report of a case.

In children with diseases of the spleen, every effort should be made to preserve the organ, to prevent severe infections postsplenectomy. We report the case of a 7-year-old girl with torsion of a wandering spleen who we treated by autotransplantation of splenic tissues following splenectomy, when fixation of the enlarged spleen seemed impossible. Spleen scintigraphy showed uptake in the regenerating splenic tissues 9 months after surgery, and evidence of an increase in the size of the tissues 23 months after surgery. Howell-Jolly bodies had disappeared by 16 months after surgery. These findings suggested that the transplanted splenic tissues were resuming splenic functions. Based on our experience with this case, we conclude that autotransplantation after splenectomy is a treatment option for wandering spleen with torsion when fixation seems difficult because of splenic congestion and enlargement.

Angiography↗

PubMed2006

Measurement of lysophospholipase D/autotaxin activity in human serum samples.

OBJECTIVES: Lysophospholipase D (lysoPLD)/autotaxin regulates the blood levels of lysophosphatidic acid (LPA), and we designed a serum lysoPLD assay for use in clinical laboratory testing. DESIGN AND METHODS: LysoPLD activity was assessed based on the amount of choline released with lysophosphatidylcholine as the substrate. RESULTS AND CONCLUSIONS: It was confirmed that the lysoPLD assay can be applied to clinical laboratory testing. The serum lysoPLD activity in healthy female subjects was significantly higher than that in the male subjects.

Clinical Laboratory Techniques↗

PubMed2006

Visceral coverage with absorbable mesh followed by split-thickness skin graft in the treatment of ruptured giant omphalocele.

We report a case of ruptured giant omphalocele in whom herniated organs were successfully covered by an absorbable mesh and a subsequent skin graft. A 2,200 g male baby was born at 35 weeks of gestation. An abdominal wall abnormality was detected by prenatal ultrasound at 21 weeks of gestation. At birth, the entire liver, stomach, and small and large bowel had herniated from the defect of the abdominal wall. The thorax and abdomen were highly underdeveloped, and attempts to reduce the organs into the abdomen were unsuccessful due to the extremely small abdominal cavity and associated pulmonary hypoplasia. To protect the herniated organs and prevent abdominal infections, the organs were covered by a polyglycan mesh and subsequently a meshed split-thickness skin graft. Ten weeks later, it was confirmed that the organs were completely covered by epithelialized tissue. However, the patient suffered from frequent respiratory infections and finally died of respiratory insufficiency. Based on the experience of the patient, we conclude that coverage of the herniated organs with an absorbable mesh and a skin graft is a recommendable treatment in ruptured giant omphalocele.

Fatal Outcome↗

PubMed2006

Efficacy of granulocyte apheresis in pediatric patients with ulcerative colitis: a pilot study.

OBJECTIVES: Granulocyte apheresis (GCAP), involving the removal of granulocytes from the blood, may improve clinical symptoms and facilitate a reduction in the dose of steroids in adult patients with ulcerative colitis. As a preliminary trial, GCAP was used to taper the dose of steroids in 4 pediatric patients with ulcerative colitis. METHODS: Three males and 1 female ranging from 11 to 17 years old were treated with GCAP once per week for 5 consecutive weeks/course. The ages of patients at clinical onset ranged from 8 to 12 years and the length of time from the clinical onset to GCAP treatment ranged from 28 to 58 months (median, 38.5 months). RESULTS: In 2 patients, symptoms and signs indicating disease activity improved after 2 courses of GCAP. Laboratory data and endoscopic findings also improved after treatment and the clinical efficacy was judged to be excellent in these patients. In 1 patient, GCAP improved laboratory and endoscopic hallmarks, but bloody stools persisted. Finally, the treatment was ineffective in the fourth patient who eventually underwent surgery. CONCLUSIONS: GCAP is effective in improving clinical symptoms and may play an important role in converting steroid therapy to other treatments in children with steroid-refractory or steroid-dependent ulcerative colitis.

Adolescent↗

PubMed2006

Role of neuronal interferon-gamma in the development of myelopathy in rats infected with human T-cell leukemia virus type 1.

Human T-cell leukemia virus type 1 (HTLV-1) is the causative agent of not only adult T-cell leukemia but also HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Among the rat strains infected with HTLV-1, chronic progressive myelopathy, named HAM rat disease, occurs exclusively in WKAH rats. In the present study, we found that HTLV-1 infection induces interferon (IFN)-gamma production in the spinal cords of HAM-resistant strains but not in those of WKAH rats. Neurons were the major cells that produced IFN-gamma in HTLV-1-infected, HAM-resistant strains. Administration of IFN-gamma suppressed expression of pX, the gene critically involved in the onset of HAM rat disease, in an HTLV-1-immortalized rat T-cell line, indicating that IFN-gamma protects against the development of HAM rat disease. The inability of WKAH spinal cord neurons to produce IFN-gamma after infection appeared to stem from defects in signaling through the interleukin (IL)-12 receptor. Specifically, WKAH-derived spinal cord cells were unable to up-regulate the IL-12 receptor beta2 gene in response to IL-12 stimulation. We suggest that the failure of spinal cord neurons to produce IFN-gamma through the IL-12 pathway is involved in the development of HAM rat disease.

Animals↗

PubMed2005

Clinical characteristics and surgical treatment of perianal and perineal rhabdomyosarcoma: analysis of Japanese patients and comparison with IRSG reports.

Rhabdomyosarcomas of the perianal and perineal regions are uncommon. This study was performed to clarify the clinical characteristics and guidelines of surgical treatment of patients with perianal and perineal rhabdomyosarcomas younger than 20 years of age. Twenty-nine patients, 26 patients identified in the Japanese literature and three of our own, were analyzed and the results were compared with the data reported from the Intergroup Rhabdomyosarcoma Study Group (IRSG). Female predominance and a twin-peak age distribution in infancy and adolescence were characteristic findings of the Japanese patients that were not observed in the IRSG studies. The demographic differences between the two groups were attributed to the differences in demographics of patients younger than 10 years of age. Of the 29 patients, 17 were categorized into clinical groups III/IV and 21 patients into stages 3/4. Alveolar histology was diagnosed in 18 patients. In patients more than 10 years of age, the female predominance was more prominent and the incidences of advanced clinical groups/stages and alveolar histology were significantly higher than those in patients younger than 10 years of age. Inguinal lymph nodes were always involved in patients with lymph node metastases and three patients developed metastases to the breast. Information regarding the survival time was available for 18 patients and the 5-year overall survival was 20%. Two patients with a group I/stage 2 tumor and one with a group II/stage 3 tumor survived for more than 2 years with no evidence of the disease. In these patients, the tumors were excised by primary surgery or primary reexcision and they were not accompanied by lymph node metastasis. Based on these data, complete tumor resection prior to chemotherapy should be pursued and the inguinal lymph nodes should be at least sampled because nodal involvement is closely associated with the patient's prognosis.

Adolescent↗

PubMed2005

The herbal medicine inchin-ko-to (TJ-135) induces apoptosis in cultured rat hepatic stellate cells.

Use of herbal remedies in the treatment of various diseases has a long tradition in Eastern medicine and the liver diseases are not an exception. In their use, lack of elucidation of mechanism(s) as well as randomized, placebo-controlled clinical trials has been a problem. Recently, we and others reported that inchin-ko-to (TJ-135), one of herbal remedies, suppressed hepatic fibrosis in animal models. In the course of clarifying the mechanism, we directed our focus on hepatic stellate cells (HSCs), playing a pivotal role in hepatic fibrosis, and found that rat HSCs cultured with TJ-135 changed their morphology to star-like configuration with thin, slender and dendritic processes with fewer stress fibers, which might be the features in apoptosis. In fact, TJ-135 induced HSC apoptosis in a time- and concentration-dependent manner as judged by the nuclear morphology, quantitation of cytoplasmic histone-associated DNA oligonucleosome fragments and caspase 3 activity. In HSCs treated with TJ-135, increased expression of p53 and decreased expression of Bcl-2 and phosphorylated Akt and Bad were determined. HSC apoptosis is shown to be involved in the mechanisms of spontaneous resolution of rat hepatic fibrosis and the agent which induces HSC apoptosis has been shown to reduce experimental hepatic fibrosis in rats. Thus, the induction of HSC apoptosis could be the mechanism how TJ-135 works on the resolution of hepatic fibrosis. Our current data may shed light on the novel effect of the herbal remedy.

Animals↗

PubMed2005

CD4+/CD8+ macrophages infiltrating at inflammatory sites: a population of monocytes/macrophages with a cytotoxic phenotype.

We found a population of nonlymphoid cells expressing both CD4 and CD8 in peripheral blood mononuclear cells (PBMCs) of human T-cell leukemia virus type-I pX transgenic rats with autoimmune diseases. These cells, which showed a monocytic phenotype, were also found in wild-type rats, and their number increased by adjuvant-assisted immunization. GM-CSF increased the number of these double-positive (DP) monocytes in PBMCs. Consistent with the idea that DP monocytes differentiate into DP macrophages at sites of inflammation, we found infiltration of DP macrophages at the site of myosin-induced myocarditis in wild-type rats; these cells exhibited a T-helper 1 (Th1)-type cytokine/chemokine profile and expressed high levels of Fas ligand, perforin, granzyme B, and NKR-P2 (rat orthologue of human NKG2D). Adoptive transfer of GFP-positive spleen cells confirmed hematogenous origin of DP macrophages. DP monocytes had a cytotoxic phenotype similar to DP macrophages, indicating that this phenotypic specialization occurred before entry into a tissue. In line with this, DP monocytes killed tumor cells in vitro. Combined evidence indicates that certain inflammatory stimuli that induce GM-CSF trigger the expansion of a population of DP monocytes with a cytotoxic phenotype and that these cells differentiate into macrophages at inflammatory sites. Interestingly, human PBMCs also contain DP monocytes.

Adjuvants, Immunologic↗

PubMed2005

Platelet release of beta-thromboglobulin and platelet factor 4 and serotonin in plasma samples.

OBJECTIVES: Platelet release of alpha granule-derived CXC chemokines and dense granule-derived serotonin in plasma samples was evaluated. METHODS: Concentrations of the CXC chemokines beta-TG and PF4 were assayed by an enzyme immunoassay; serotonin was measured by an HPLC method. RESULTS: Beta-TG and PF4 were more easily released than serotonin by in vitro procedures. Use of the anti-platelet cocktail CTAD and preservation of the samples at 4 degrees C were necessary to accurately measure beta-TG and PF4, but not serotonin. CONCLUSIONS: Assaying serotonin may be useful for assessing platelet activation in vivo as a laboratory test because of facile preparation of plasma samples.

Adenosine↗

PubMed2005

Aberrant gene expression by CD25+CD4+ immunoregulatory T cells in autoimmune-prone rats carrying the human T cell leukemia virus type-I gene.

Transgenic rats expressing the env-pX gene of human T cell leukemia virus type-I under the control of the viral long terminal repeat promoter (env-pX rats) developed systemic autoimmune diseases. Prior to disease manifestation, the immunosuppressive function of CD25(+)CD4(+) T (T-reg) cells was impaired in these rats. Since T cell differentiation appeared to be disordered in env-pX rats, we assumed that the impairment of T-reg cells might be caused by an abortive differentiation in the thymus. However, reciprocal bone marrow transfers between env-pX and wild-type rats revealed that direct effects of the transgene unrelated to the thymus framework induced the abnormality of T-reg cells. To identify molecular changes, comparative analyses were done between env-pX and wild-type T-reg cells. Expression of the Foxp3 gene and cell-surface markers supported a naive phenotype for env-pX T-reg cells. Array analyses of gene expression showed some interesting profiles, e.g. up-regulation of genes associated with the Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathways in env-pX T-reg cells. Additionally, expression of the suppressor of cytokine signaling (SOCS) family genes, which inhibit the JAK/STAT signals, was extremely low in env-pX T-reg cells. These findings suggest that the transgene may mediate the down-regulation of the SOCS family genes and that subsequent excess signals through the JAK/STAT pathways may result in the loss of function of env-pX T-reg cells. We suggest that investigation of the pathology of T-reg cells in our autoimmune-prone rat model may aid in understanding the roles of T-reg cells in human autoimmune diseases.

Animals↗

PubMed2005

Down-regulation of CD9 in human ovarian carcinoma cell might contribute to peritoneal dissemination: morphologic alteration and reduced expression of beta1 integrin subsets.

Peritoneal dissemination is one of the main causes of death in cancer patients. Pathophysiology of metastasis has been well investigated, but the mechanism of diffuse spread of tumor colonies in the peritoneal cavity is not fully understood. CD9 is a member of tetraspanin and its down-regulation is known to be involved in poor prognosis. To investigate the significance of the down-regulation of CD9, HTOA, an ovarian carcinoma cell line that highly expressed CD9, was transiently transfected with small interfering RNA (siRNA) against CD9, and CD9-negative cells (HTOA(CD9-)) were purified. HTOA(CD9-) showed altered adhesion patterns on Matrigel, collagen, fibronectin, and laminin compared with those of control siRNA-transfected HTOA (control-HTOA). Flow cytometry and fluorescence cytostainings revealed that the expression levels of integrins beta1, alpha2, alpha3beta1, alpha5, and alpha6 were lower in HTOA(CD9-) than those of control-HTOA. HTOA(CD9-) showed altered expression of junctional and cytoskeletal molecules. By time-lapse video microscopy, control-HTOA showed solid adhesion to extracellular matrix and formed cobblestone pattern, whereas HTOA(CD9-) showed weaker adhesion and were distributed as diffuse spots. To examine whether the expression level of CD9 change during tumor dissemination, HTOA-P, a highly disseminative subclone of HTOA, was established. HTOA-P showed distinctive down-regulation of CD9 at mRNA and protein levels, and showed similar morphologic alteration as HTOA(CD9-) did. These findings indicate that the down-regulation of CD9 may be an acquired event in the process of tumor dissemination. Down-regulated CD9 may attenuate the expression of several integrins and rearrange junctional and cytoskeletal molecules that might contribute to dissemination of ovarian carcinomas.

Adenocarcinoma↗

PubMed2005

Chronic graft-versus-host disease-like autoimmune disorders spontaneously occurred in rats with neonatal thymus atrophy.

We earlier reported that the human T cell leukemia virus type-1 pX gene transduced into rat thymic epithelial cells had an impact on biology of the cells. We report here that FW-pX rats born by mating of F344 transgenic rats expressing the pX gene without tissue specificity with nontransgenic Wistar rats developed disorders, including atrophy of the thymus, lymphocytopenia, and inflammatory cell infiltration into multiple organs, similar to events in chronic graft-vs.-host disease (GVHD). Vanishment of thymic epithelial cells especially in the cortex and marked depletion of CD4 CD8 double-positive thymocytes were evident in the neonatal thymus in these rats. The relative abundance of CD8 compared to CD4 T cells may be related to dominant infiltration of CD8 T cells into the affected organs. Additionally, adoptive transfer of FW-pX splenocytes could induce lymphocytic infiltration into sublethally irradiated wild-type syngeneic recipients. Analysis of the expression level of the Foxp3 gene in peripheral blood mononuclear cells revealed that the numbers of immunoregulatory T cells were less in FW-pX rats than in wild-type rats. The collective evidence suggested that the FW-pX rats spontaneously developed chronic GVHD-like autoimmune diseases, following abortive differentiation of T cells in the thymus in early days of the newborn. This rat model may shed light on the pathogenesis of chronic GVHD and also other systemic autoimmune diseases, the etiology of which is unknown.

Animals↗

PubMed2005

Secretion and expression of epithelial markers supports the biliary origin of solitary nonparasitic cyst of the liver in infancy.

Solitary nonparasitic cyst of the liver (SNPCL) is rare in children. Although there are several hypotheses regarding the pathogenesis, the true origin of SNPCL remains unknown. The authors present an infant with a huge SNPCL in whom the epithelial markers, CA19-9, DU-PAN-2, and SPan-1, were elevated in the serum and cystic fluid. The presence of CA19-9 and DU-PAN-2 was shown by immunohistochemistry in the cystic epithelia. These indicate that the classical idea of biliary origin of SNPCL is supported.

Antigens, Neoplasm↗

PubMed2005

Prediction of lymphatic invasion/lymph node metastasis, recurrence, and survival in patients with gastric cancer by cDNA array-based expression profiling.

BACKGROUND: We assessed the predictability of various classes of gastric carcinoma defined by clinicopathological parameters, such as invasiveness and clinical outcomes, using cDNA array data obtained from 54 cases. MATERIALS AND METHODS: We searched an optimal combination of genes to discriminate the classes defined with the clinicopathological parameters by using a feature subset selection algorithm, which was applied to a set of genes preselected on the basis of statistical difference in expression (two-sided t test, P < or = 0.05). With the selected features (gene set), we evaluated the predictability of each parameter in a leave-one-out cross-validation test. RESULTS: We successfully selected sets of genes for which the classifier predicted better versus worse overall survival (tumor-specific death) and tumor-free survival (recurrence), with respective classification rates of 94 and 92%. A contingency table analysis (chi2 test) and Cox proportional hazard model analysis revealed that lymph node metastasis is the most important factor (confounding factor) in patients' prognoses and risks of recurrence. The feature subset selection procedure successfully extracted expression patterns characteristic of lymph node metastasis and lymphatic vessel invasion, yielding 92 and 98% prediction accuracies for these respective factors. CONCLUSION: We conclude that expression profiling using feature subset selection provides a powerful means of stratification of gastric cancer patients in regard to the prognostic factors. Further studies should be warranted to apply this method to personalization of the treatment options.

Adenocarcinoma, Mucinous↗

PubMed2005

Right- and left-sided colorectal cancers display distinct expression profiles and the anatomical stratification allows a high accuracy prediction of lymph node metastasis.

Accurate preoperative prediction of lymph node metastasis and degree of tumor invasion would facilitate an appropriate decision of the extent of surgical resection of cancers to reduce unnecessary complication or to minimize the risk of recurrence in patients. We analyzed gene expression profiles characteristic of the invasiveness of colorectal carcinoma in a total of 89 cases, using a cDNA array and pattern classification algorithms. We set binary classes for a panel of clinicopathologic parameters, each of which was divided at different levels for categories (discrete) or values (continuous). We searched an optimal combination of genes to discriminate the classes by using of a feature subset selection algorithm, which was applied to a set of genes preselected on the basis of statistical difference in expression (two-sided t test, P < or = 0.05). We used a sequential forward feature selection which additively searched a combination of genes, giving a minimal leave-one-out classification error rate of a k-nearest neighbor classifier. In the process of gene preselection, we found a remarkable difference in the expression pattern of genes according to the anatomical location of cancers. The difference was most prominent when the classes were set for cecum, ascending colon, transverse colon, and descending colon (CATD) versus sigmoid colon and rectum (SR). By stratifying these two locations, we were able to extract gene expression profiles characteristic of the classes of the presence versus absence of lymph node metastasis, lymphatic invasion, vascular invasion and degree of mural invasion, and pathological stages, with an accuracy of more than 90%. These results suggest that colorectal cancers harbor distinct molecular pathophysiological statuses according to their right-to-left locations, of which stratification is important for pattern classification of cDNA array data.

Adult↗

PubMed2005

Malignant transformation of thymoma in recipient rats by heterotopic thymus transplantation from HTLV-I transgenic rats.

Transgenic rats expressing the pX gene of human T lymphocyte virus type-I (HTLV-I) under control of the rat lymphocyte-specific protein tyrosine kinase type-I promoter (lck-pX rats) developed benign epithelial thymomas. When the thymuses of newborn lck-pX rats were transplanted into the subcapsular space of the kidney in other thymectomized lck-pX rats, similar tumors developed in the transplanted thymuses. Following the tumor growth, dissemination in the abdominal cavity and distant metastasis occurred. The tumors were histopathologically similar to the original thymomas, but prominent nuclear atypia and high mitotic activity were present. The Ki-67 index was twice as high as that in the originals. The tumors were transplantable into the subcutis of lck-pX rats, although transplantation of the originals never succeeded. All evidence indicated that malignant transformation of thymoma was induced by the heterotopic transplantation. Expression of the pX transgene in the transformed tumors were significantly reduced. Among host genes, the expression of p16ink4a/ARF, which was significantly upregulated in the originals, was never detected in the transformed tumors. Genomic Southern blots and PCR suggest that homozygous deletion of the p16ink4a/ARF gene may play important roles in malignant transformation in this model. Our model described here is a useful unique model for in vivo malignant transformation.

Animals↗