Biomedical subjects

Katsuhiko Arai

Publications and source records attributed to Katsuhiko Arai.

14 recordsLinked to original sources

PubMed2006

Gene expression analysis in mice liver on hepatocarcinogenesis by flumequine.

mRNA expression profiles in the liver from mice treated with flumequine (FL) were analyzed in order to elucidate the mechanism of its tumor-promoting effect. The liver from a C3H/He mouse that received a diet containing 4,000 ppm of FL for 4 weeks was examined by cDNA microarray in comparison with an untreated mouse. Furthermore, to obtain a more comprehensive sequence, time-course changes in selected genes were determined by real-time RT-PCR. Microarray analysis revealed 15 upregulated and 9 downregulated genes in an FL-treated mouse. The upregulated genes included signal transducers and cell cycle regulators. In addition, the levels of stress response genes, particularly glutathione S-transferase (GST) alpha and GSTmu, were very high, indicating the generation of oxidative stress. On the other hand, the downregulated genes included phase I metabolic enzymes, such as cytochrome P450 (CYPs) enzymes, and apoptosis-associated proteins. These changes were confirmed by quantitative RT-PCR and were generally consistent with each other. Time-course observations revealed consistent results, particularly with regard to GSTalpha, GSTmu, ERK5, and CYP2E1. In addition, the expression of 8-oxoguanine DNA glycosylase 1 (OGG1) was increased in a time-dependent manner. These results suggest the possibility that responses against oxidative stress may play a major role in hepatocarcinogenesis by FL in mice.

Animals↗

PubMed2006

Restorative proctocolectomy for pediatric patients with ulcerative colitis.

PURPOSE: A restorative proctocolectomy has become an elective surgical treatment for patients with ulcerative colitis (UC). In children with UC, however, the role of this procedure has not yet been well evaluated. We investigated the postoperative status of pediatric patients with UC regarding the side effects of steroids, postoperative complications, and growth. METHODS: The medical records of 15 patients with UC who underwent a restorative proctocolectomy between August 1993 and October 2003 were retrospectively reviewed. RESULTS: Their mean age was 12.6 +/- 3.4 years (range 5.7-15.7; boys: 9, girls: 6). All patients had total colitis, except for one who had left-sided colitis. The mean cumulative dose of preoperative prednisolone was 6201 +/- 7980 mg (mean +/- SD). The operative indications were an unsuccessful response to medical treatments in 12 patients (80%) and severe colitis in 3 patients (20%). Surgery was performed in one stage in 6 patients and in two stages in 9 patients. Seven patients (47%) demonstrated growth retardation at the time of operation. Steroid-related complications were seen in 3 cases, i.e., steroid myopathy, glaucoma, and cataracts, respectively. As early postoperative complications, an intestinal obstruction was seen in 2 patients, peritonitis in 1, and pancreatitis in 1. As late complications, anastomotic stenosis was observed in 5 patients, pouchitis in 4, residual proctitis in 3, and anal or proctovaginal fistula in 2. An intestinal obstruction, peristomal pyoderma gangrenosum, and dehydration each was seen in 1 patient. A growth "catch-up" was obtained for all but one patient. All patients became free of corticosteroids. CONCLUSION: A restorative proctocolectomy was found to be an effective treatment alternative even in children with UC when conservative therapy proves to be ineffective.

Adrenal Cortex Hormones↗

PubMed2006

Regulation of class II beta-tubulin expression by tumor suppressor p53 protein in mouse melanoma cells in response to Vinca alkaloid.

The continuous exposure of antimicrotubule drugs to tumors often results in the emergence of drug-resistant tumor cells with altered expression of several beta-tubulin isotypes. We found that Vinca alkaloid enhanced expression of class II beta-tubulin isotype (mTUBB2) in mouse B16F10 melanoma cells via alteration of the tumor suppressor p53 protein. Vincristine treatment stimulated an increase in mTUBB2 mRNA expression and promoted accumulation of this isotype around the nuclei. Transient transfection assays employing a reporter construct, together with site-directed mutagenesis studies, suggested that the p53-binding site found in the first intron was a critical region for mTUBB2 expression. Electrophoretic mobility shift assay and associated antibody supershift experiments showed that vincristine promoted release of p53 protein from the binding site. In addition, exogenous induction of TAp63gamma (p51A), a homologue of p53, canceled the effect of vincristine on mTUBB2 expression. These results suggest that p53 protein may function as a suppressor of mTUBB2 expression and vincristine-mediated inhibition of p53 binding results in enhanced mTUBB2 expression. This phenomenon could be related with the emergence of drug-resistant tumor cells induced by Vinca alkaloid and may participate in determining the fate of these cells.

Amino Acid Sequence↗

PubMed2006

[Clinical experiences of five cases with ulcerative colitis and recto- or anovaginal fistula].

Clinical aspects, treatment and outcome of five patients with ulcerative colitis recto- or anovaginal fistula and were studied retrospectively. All patients had total colitis (relapse and remission type) and more than a 5 year history of ulcerative colitis. They all had anorectal complications, such as periproctal abscess, stenosis of fistula. Four patients had total colectomy with an ileal pouch anal canal anastomosis for intractability or dysplasia. One was treated conservatively. Complete closure of fistula was obtained in two patients;in one patient rectum was resected below the fistula and in one patient defect of the vaginal posterior wall was reconstructed by using a gluteal fold flap following colectomy. Recto- or anovaginal fistula complicating ulcerative colitis is rare but may occur in the patients with severe rectal inflammation and they can be managed by restorative proctocolectomy with an ileal pouch anal or anal canal anastomosis.

Adult↗

PubMed2005

Incidence and outcome of complications following restorative proctocolectomy.

BACKGROUND: Complications were analyzed in 296 patients with ulcerative colitis who underwent restorative proctocolectomy. METHODS: In 96.3% of patients, the pouch was anastomosed using the double stapling method. A total of 44.6% of patients underwent restorative proctocolectomy in 1 stage without ileostomy and 53% in 2 stages. Complications were divided into 2 stages: early (within 1 month) and late (after 1 month); moreover, the annual incidences were calculated, mean onset time, and pouch survival rate. RESULTS: The overall incidence of complications was 52.7%. Early complications (13.2%) occurred significantly less often than late complications (46.3%) (P < .05). Thirty-five (17.7%) of 198 complications required surgery. The cumulative 5- and 10-year pouch survival rate was 99%, respectively. CONCLUSIONS: The rate of complications after restorative proctocolectomy was almost equivalent to that in other reports, but the pouch survival rate was very high.

Adult↗

PubMed2005

Unilateral basement membrane zone alteration of the regenerated laminar region in equine chronic laminitis.

Between the laminar epidermis and the laminar dermis of laminar region (LR) in equine foot, it can be observed the basement membrane zone (BMZ), which is composed of a basement membrane and its accompaniments like the hemidesmosome and anchoring fibril. Alteration in the BMZ in equine laminitis is possibly related with not only development but also recovery outcome and recurrence of this disease. However, there is little known about the structure of the BMZ during the recovery phase of this disease. To assess the condition of the BMZ of LR affected by chronic laminitis, the tissue was examined in three cases at two weeks, four weeks and three months after the onset of laminitis, using pathological, immunohistochemical and electron microscopic techniques. Histologically in all laminitis cases, there was a regenerated laminar epidermis with proliferating keratinocytes between the Stratum medium and the dermis, but it included the undeveloped secondary epidermal laminae (ud-SELs) structure in one side of the primary epidermal laminae, especially in the part of the deep area of LR. Immunohistochemical results were positive for the anti-type IV collagen, anti-type VII collagen and anti-laminin 5 antibodies in the most BMZs. However, partial BMZs adjacent to the ud-SELs were negative for the anti-type VII collagen and anti-laminin 5 antibodies. Ultrastructurally, in the BMZ of the ud-SEL, the lamina densa and the lamina lucida were present. In contrast, the anchoring fibrils and the hemidesmosomes were either absent, or present at lower than normal levels. In conclusion, the present study indicated that the part of regenerated LR in chronic laminitis was not able to fully restore to construct the BMZ for a long time, especially in the unilateral side of laminar epidermis. It might be related with recurrence of this disease.

Animals↗

PubMed2005

On-line microdevice for stress proteomics.

The handling of the cells or tissues is essential for proteomics research or drug screening, where labor is not avoidable. The steps of cell wash, protein extraction, protein denaturing are complicated procedures in conventional method using centrifugation and pipetting in the laboratory. This is the bottle-neck for proteome research. To solve these problems, we propose to utilize the nanotechnology, which will improve the proteomics methodology. Utilizing the nanotechnology, we developed a novel microseparation system, where centrifugation and pipetting are needless. This system has a nanostructured microdevice, by which the cell handling, protein extraction, and antibody assay can be performed. Since cell transfer is needless, all cells are corrected without any loss during the cell-pretreatment procedures, which allowed high reproducibility and enabled the detection of low amount of protein expression. Utilizing the microdevice, we analyzed the stress induced proteins. We further succeeded the screening of food that was useful for immunity and found that an extraction from seaweed promoted the apoptosis of T-lymphoblastic cells. Here, we present an on-line microdevice for stress proteomics.

Nanotechnology↗

PubMed2005

[Surgical treatment for ulcerative colitis--recent advances].

Surgical indication for ulcerative colitis is fulminant colitis, intractability, cancer or dysplasia. New surgical indication should be established because new medical treatment such as leucocytoapheresis or intravenous cyclosporine treatment developed. Standard surgical procedure is ileal pouch anal anastomosis with rectal mucosal stripping and stapled ileal pouch anal anastomosis. Postoperative bowel function and QOL are satisfactory in both of them. Surgical treatment should be performed without any delay for the patients who do not respond medical treatment.

Colitis, Ulcerative↗

PubMed2003

Morphological characterization of skin ganglion-like cells in Djungarian hamsters (Phodopus sungorus).

Characteristic ganglion-like cell proliferation observed in the skin of Djungarian hamsters was investigated using 24 male and 24 female hamsters, 1-6 months of age, to examine the anatomic location of these ganglion-like cells and their morphologic features. One abdominal skin tumor composed of these cells and resembling proliferative fasciitis in humans was also examined. Skin ganglion-like cells were rarely observed in young animals but increased in number and extent with age, especially in males. These cells were frequently seen in the ventral and medial regions of the trunk and legs rather than in the dorsal and lateral regions. Light microscopic examination of these ganglion-like cells revealed abundant vesicular basophilic cytoplasm with delicate intracytoplasmic silver stain-positive fibrils. Ultrastructurally, these cells contained abundant rough endoplasmic reticulum and Golgi complexes with dilated cisternae; intracellular collagen fibrils were present within these cisternae. Heat shock protein 47, beta-tubulin, and androgen receptor were expressed in these cells. The morphologic features of cells of one tumor resembling human proliferative fasciitis were identical to those observed in ganglion-like cells. The results of the present study suggest that these ganglion-like cells are derived from intrinsic undifferentiated mesenchymal cells in the dermis or subcutaneous adipose tissue and that any tumor-like lesion they form should be regarded as an abnormal proliferative lesion of skin ganglion-like cells rather than as proliferative fasciitis or fibroma.

Abdominal Neoplasms↗

PubMed2002

Distribution of the class II beta-tubulin in developmental and adult rat tissues.

During a screen of monoclonal antibodies raised against a cytoskeletal preparation of neonatal rat cerebrum, we have identified a monoclonal antibody, MAb58A, that is specific for the class II beta-tubulin isotype. Immunoscreening of a rat brain cDNA library using MAb58A yielded the cDNA retaining a class II-specific nucleotide sequence. The specificity of MAb58A to the class II beta-tubulin isotype was confirmed by immunoreactivity to synthetic peptides corresponding to isotype-specific sequence of class I, II, III, IVa, or IVb. Further, the results of an immunoassay against a series of overlapping octapeptides derived from a class II-specific region revealed that the antibody epitope was a heptapeptide that consists of Glu-Glu-Glu-Glu-Gly-Glu-Asp (EEEEGED). Immunoblot analysis revealed that the class II isotype represented a significant portion of beta-tubulin present in the adrenal gland, brain, and testis of adult rats. In fetal tissues, this isotype was detected in skeletal muscle, as well as in the brain. Immunohistochemically, MAb58A reacted predominantly with components of the developing rat nervous system, such as migrating neuroblasts, peripheral nerves and ganglion cells, and sensory organs. MAb58A-immunoreactivity was also found in developing skeletal and smooth muscle cells, chondrocytes, and vascular endothelia. In adults, MAb58A-immunoreactivity was remarkably diminished, but persisted in peripheral nerves and ganglion cells, chondrocytes, and capillary components. Together, our results demonstrate that MAb58A is specific for the class II beta-tubulin isotype, which may retain an embryonic nature in both neuronal and non-neuronal tissues.

Animals↗

PubMed2002

Immunohistochemical study of membrane type-matrix metalloproteinases (MT-MMPs) and matrix metalloproteinase-2 (MMP-2) in dermatofibroma and malignant fibrous histiocytoma.

Matrix metalloproteinases (MMPs) play an important role in tumor invasion and metastasis. Enhanced expression of matrix metalloproteinase-2 (MMP-2) has been demonstrated in dermatofibroma (DF) and malignant fibrous histiocytoma (MFH). MMP-2 has been shown to be activated by membrane-type MMPs (MT-MMPs). To study the role of MT-MMP in the activation of MMP-2, skin specimens of DF (five cases) and MFH (three cases) were immunohistochemically studied using in situ zymography and the antibodies against matrix metalloproteinase-2 (MMP-2) and membrane type 1-3-MMPs (MT1-3-MMPs). Both MMP-2 activity and its expression were significantly activated in the tumor cells in DF and MFH. Anti-MT2-MMP strongly reacted with tumor cells of all cases of DF and MFH, whereas anti-MT1 or 3-MMP antibody showed a weak reaction in some cases of DF and MFH. Double immunofluorescence labeling demonstrated that the immunoreactive cells with anti-MMP-2 antibody in DF and MFH consistently reacted with anti-MT2-MMP antibody. The results suggest that the activation of MMP-2 in the benign and malignant fibrous tumors is related to the activation of MT-MMPs.

Adolescent↗

PubMed2002

TGF-beta alters collagen XII and XIV mRNA levels in cultured equine tenocytes.

The effects of TGF-beta 1, beta 2 and beta 3 (TGF-beta) on levels of mRNA corresponding to the alpha chains of type XII and type XIV collagens in equine tenocyte cultures were assessed using the ribonuclease protection assay (RPA). The level of alpha1(XII) mRNA in untreated monolayer cultures was approximately 50- to 100-fold greater than alpha1(XIV) mRNA level. Addition of TGF-beta resulted in an increase in the amount of alpha1(XII) present and a decrease of alpha1(XIV) mRNA in a dose-dependent manner. Specifically, the level of alpha1(XII) mRNA was doubled, but alpha1(XIV) was decreased to 30% of control by the addition of 2 ng/ml of TGF-beta 1 to the cultures. These effects were completely abrogated by neutralizing antibody specific for TGF-beta. In addition, electron microscopy demonstrated that bundled collagen fibers were formed in the intercellular spaces of multilayered tenocytes which had been cultured for 2 weeks in the presence of exogenous TGF-beta 1 together with ascorbic acid phosphate. These results suggest that type XII and/or type XIV collagens modulate the structure of ECM formed by tenocytes in culture.

Animals↗

PubMed2002

Dynamics of messenger RNAs encoding inhibin/activin subunits and follistatin in the ovary during the rat estrous cycle.

Quantitative changes in ovarian inhibin/activin subunit and follistatin mRNAs during the rat estrous cycle were examined by ribonuclease protection assay using digoxygenin-labeled RNA probes. Levels of ovarian inhibin alpha subunit mRNA remained low throughout estrus, metestrus, and diestrus; abruptly increased on the morning of proestrus; then rapidly decreased when the primary gonadotropin surge occurred. A similar changing pattern was observed in inhibin/activin beta(A) subunit mRNA. On the other hand, inhibin/activin beta(B) subunit mRNA showed a different changing pattern. Levels of beta(B) subunit mRNA remained constant during metestrus and diestrus, abruptly decreased on the afternoon of proestrus, then quickly recovered from the nadir by 1100 h on estrus. Throughout the rat estrous cycle, especially during the periovulatory period, alpha subunit mRNA levels were considerably higher than beta(A) and beta(B) subunit mRNA levels. In addition, changes in plasma concentrations of inhibin A and inhibin B were very similar to that in ovarian beta(A) and beta(B) subunit mRNA levels, respectively, with several-hour delays. These results suggest that levels of beta subunit mRNAs restrict secretion of dimeric inhibins. Levels of follistatin mRNA remained low from the midnight of metestrus to the midnight of diestrus, then increased until initiation of the primary gonadotropin surge. Thereafter, follistatin mRNA decreased, reached the nadir at 0200 h on estrus, then increased abruptly at 1100 h on estrus. Afterward, follistatin mRNA levels remained high until the morning of metestrus. The changing pattern of ovarian follistatin mRNA was similar to, and preceded, the changes in plasma concentrations of progesterone, suggesting that ovarian follistatin may modulate progesterone secretion during the rat estrous cycle.

Activins↗

PubMed2002

Expression of desmosomal proteins in rat keratinocytes during in vitro differentiation.

The keratinocyte, the major component of the epidermis, expresses several proteins that characterize the keratinization during the differentiation. Proliferation and differentiation of cultured human keratinocytes are known to be regulated by the Ca2+ concentration in the culture medium. However, informations about the rat keratinocyte are relatively limited and their physiology is still an open question. To elucidate the characteristics of the rat keratinocyte, we established rat keratinocyte culture system and examined effects of extracellular calcium concentration on the expression of differentiation-related proteins. Keratinocytes were isolated from the newborn rat skin with 0.25% trypsin, followed by separation with a Percoll density gradient. The separated cells were grown in MCDB 153 medium containing several growth factors and Ca(2+)-free fetal bovine serum, then stimulated with Ca2+. Immunoblotting demonstrated strong expression of beta1 integrin in unstimulated cells, suggesting that the primary culture of rat keratinocytes was successfully established. Expression of desmoglein and transglutaminase was increased by Ca2+ stimulation, whereas beta1 integrin expression was decreased in response to increasing concentrations of Ca2+. These observations indicate that cultured rat keratinocytes maintain the ability to differentiate in vitro, which is similar to that of the basal keratinocytes in the epidermis.

Animals↗