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T Aoyagi

Publications and source records attributed to T Aoyagi.

At least 37 records · Page 2Linked to original sources
PubMed2001

Importance of NF-kappaB in rheumatoid synovial tissues: in situ NF-kappaB expression and in vitro study using cultured synovial cells.

OBJECTIVES: To examine whether inhibition of NF-kappaB induces apoptosis of human synovial cells stimulated by tumour necrosis factor alpha (TNFalpha), interleukin 1beta (IL1beta), and anti-Fas monoclonal antibody (mAb). METHODS: The expression of proliferating cell nuclear antigen (PCNA), NF-kappaB, and the presence of apoptotic synovial cells were determined in synovial tissues. Apoptosis of cultured synovial cells was induced by inhibition of NF-kappaB nuclear translocation by Z-Leu-Leu-Leu-aldehyde (LLL-CHO). The activation of caspase-3 and expression of XIAP and cIAP2 in synovial cells in LLL-CHO induced apoptosis was also examined. RESULTS: Abundant PCNA+ synovial cells were found in rheumatoid arthritis (RA) synovial tissue, though a few apoptotic synovial cells were also detected in the RA synovial tissues. Nuclear NF-kappaB was expressed in RA synovial cells. Electrophoretic mobility shift assay showed that treatment of cells with TNFalpha or IL1beta significantly stimulated nuclear NF-kappaB activity. A small number of apoptotic synovial cells expressing intracellular active caspase-3 were found after treatment of cells with LLL-CHO. Although treatment of RA synovial cells with TNFalpha or IL1beta alone did not induce apoptosis, apoptosis induced by LLL-CHO and caspase-3 activation were clearly enhanced in TNFalpha or IL1beta stimulated synovial cells compared with unstimulated synovial cells. Furthermore, induction of apoptosis of synovial cells with caspase-3 activation by anti-Fas mAb was clearly increased by LLL-CHO. The expression of cIAP2 and XIAP in synovial cells may not directly influence the sensitivity of synovial cells to apoptosis induced by LLL-CHO. CONCLUSION: The results suggest that NF-kappaB inhibition may be a potentially important therapeutic approach for RA by correcting the imbalance between apoptosis and proliferation of synovial cells in RA synovial tissue.

Antibodies, Monoclonal↗
PubMed2001

Maturation-dependent differences in regulation of sarcoplasmic reticulum Ca(2+) ATPase in sheep myocardium in response to pressure overload: a possible mechanism for maturation-dependent systolic and diastolic dysfunction.

We have previously demonstrated that pressure-overload hypertrophy in adult sheep is associated with myocardial dysfunction whereas that in young lambs is associated with normal contractility. To probe for possible mechanisms of these age-dependent differences, we assessed mRNA expression of genes encoding critical components of myocardial Ca(2+) handling in the same animal model. We studied left ventricular myocardium of young and adult sheep with short-term (48 h) and long-term (6 wk) pressure overload induced by ascending aortic constriction. Six weeks of pressure overload induced the significant left ventricular hypertrophy (36 and 39% increase in left ventricular/body weight ratio in lambs and sheep, respectively). The Ca(2+) ATPase and Na(+)/Ca(2+) exchanger mRNA decreased with pressure overload only in the adult (p < 0.05). Ca(2+) channel mRNA was slightly increased by pressure overload regardless of age (p < 0.05). Calsequestrin, sarcoplasmic reticulum Ca(2+) release channel, or myosin heavy-chain mRNA levels did not significantly differ. In adult sheep after 6 wk of pressure overload, decreases in load-adjusted midwall shortening (systolic dysfunction) and prolongation of relaxation time constant (diastolic dysfunction) correlated with decreases in Ca(2+)-ATPase mRNA. The sarcoplasmic reticulum Ca(2+)-ATPase protein level and Ca(2+) uptake activity of isolated sarcoplasmic reticulum vesicles were depressed only in the adult with pressure-overload hypertrophy but not in the young. We demonstrated age-dependent differences in mRNA expression of Ca(2+)-handling protein genes in response to pressure overload, which preceded the occurrence of hypertrophy and myocardial dysfunction. Thus, altered expression of Ca(2+)-handling protein genes may be one of the primary responses to pressure overload rather than a phenomenon secondary to myocardial hypertrophy.

Animals↗
PubMed2001

Pleomorphic rhabdomyosarcoma in a cow.

In a 5-year-old Holstein cow, a neoplasm composed of a large intramuscular mass and multiple metastases in the lungs and lymph nodes was diagnosed as a pleomorphic rhabdomyosarcoma. This neoplasm was characterized by marked variation in tumor cell size and giant cells with single bizarre nuclei. Although the presence of cross striations and myoglobin could be confirmed, expression of alpha-smooth muscle actin (SMA) was also recognized in a few cells. Neoplastic cells showing intense staining for desmin, vimentin and proliferating cell nuclear antigen irrespective of their size differed from those in an embryonal rhabdomyosarcoma that exhibited a wide spectrum of differentiation, reminiscent of normal skeletal myogenesis. The cellular pleomorphism and SMA expression seemed to be characteristic of deviation from normal muscle cells or satellite cells in adult muscle.

Actins↗
PubMed2001

Occurrences of candidiasis in a Fisher's lovebird and a budgerigar.

Two cage birds, a two-month-old Fisher's lovebird (Agapornis fischeri) and a one-year-old budgerigar (Melopsittacus undulatus), manifested clinical symptoms with general weakness, loss of appetite and ruffled feathers, then died. Pathological findings revealed a large quantity of yellowish-white pseudomembrane on the mucosal membrane of the esophagus and crop in these two birds. Histopathologically, blastospores (5.5 microm long x 3.4 microm wide) and pseudohyphae were detected in the lesions of conspicuous parakeratosis and moderate acanthosis in the stratified squamous epithelium. These two birds were diagnosed as having had candidiasis.

Animals↗
PubMed2001

Resistance of Mycobacterium tuberculosis to four first-line anti-tuberculosis drugs in Japan, 1997.

SETTING: Five years after the last survey of drug-resistant tuberculosis in Japan, a nationwide survey was conducted by the Tuberculosis Research Committee. OBJECTIVE: To determine the prevalence of and risk factors for resistance to four first-line anti-tuberculosis drugs. DESIGN: Cultures were obtained from patients hospitalized at 78 hospitals in different districts of Japan throughout a 6-month period, 1 June-30 November 1997. Drug susceptibility testing was carried out at the Research Institute of Tuberculosis, Tokyo, one of the supranational reference laboratories of the WHO/IUATLD global project. RESULTS AND CONCLUSION: Among patients with no prior treatment, resistance to any of the four drugs was found in 10.3%, and the prevalence of primary multidrug resistance (MDR) was 0.8%. The prevalence of acquired resistance was 42.4% for any of the four drugs and 19.7% for MDR, indicating a high prevalence rate compared with those reported in the WHO/IUATLD global project. About 73% of resistant isolates from new cases were resistant to one drug, while 64.3% of resistant isolates from the re-treatment cases were resistant to two or more drugs (P < 0.0001). No significant differences in resistance rates by sex, age group, nationality, district, and/or accompanying diseases were observed in any of the new or re-treatment cases. Other factors associated with the high prevalence in re-treatment cases remain to be determined.

Antitubercular Agents↗
PubMed2001

[A study on resistance of Mycobacterium tuberculosis to four first-line anti-tuberculosis drugs in Japan: comparison of results in the local facilities and in the reference laboratory, in 1997].

Five years after the last survey of drug-resistant tuberculosis in Japan, a nationwide survey was conducted by the Tuberculosis Research Committee (Ryoken). A total of 78 hospitals in various districts of Japan participated in this cooperative study. Each collaborating laboratory sent all the isolated mycobacterial cultures during June 1 to November 30, 1997 to the Research Institute of Tuberculosis (RIT), which is one of the Supranational Reference Laboratories of the WHO/IUATLD Global Project on Anti-tuberculosis Drug Resistance Surveillance. At RIT identification and drug susceptibility of Mycobacterium tuberculosis isolates were reexamined. The RIT received a total of 2,167 cultures. Among them, 523 cultures were excluded from further examinations because of various reasons, such as growth of mycobacteria other than tubercle bacilli (MOTT, 453), mixed cultures of M. tuberculosis and MOTT (16), and contamination or non-viability (54). Thus drug susceptibility test results were available for 1,644 cultures, including 47 from foreign-born people. In the local laboratories, the absolute concentration method using 1% Ogawa egg slant (standard method, 26 hospitals), its modified methods using a 48-well plate (Microtiter method, 29 hospitals) and a 16-well plate (Well-pack method, 7 hospitals), combination of above 2 or 3 methods (13 hospitals), and other method (3 hospitals) were used for drug susceptibility testing, and the proportion method using 1% Ogawa egg slant was used in the RIT. The results in the local laboratories were compared with those in the RIT. A high concordance rate (over 90%) was seen in the testing for 1 microgram/ml of isoniazid (INH), rifampin (RFP) and streptomycin (SM), but the rate was lower (under 90%) in the testing for 0.1 microgram/ml of INH and ethambutol (EMB). However, there was no significant difference in the concordance rates according to the test drugs among methods for drug susceptibility testing used in the local laboratories. Median concordance rates between the results with the standard method, Microtiter method and Well-pack method in the local laboratories, and those in the RIT were 95.9%, 93.2% and 96.4% respectively. Relatively lower concordance rates were seen in the laboratories using the Microtiter method related to high overestimation rates (median overestimation rate of 5.3%), compared with 1.2% and 2.3% in the laboratories using the standard method and Well-pack method, respectively. However, relatively lower concordance rates (less than 90%) were seen in the laboratories using any of the three methods, indicating that there are variations among facilities. Part of the results concerning the resistance patterns to four first-line anti-tuberculosis drugs were reported elsewhere.

Ethambutol↗
PubMed2000

Calcineurin is activated in rat hearts with physiological left ventricular hypertrophy induced by voluntary exercise training.

BACKGROUND: Calcineurin may play a pivotal role in the signaling of cardiac hypertrophy; since this hypothesis was first put forward, controversial reports have been published using various experimental models. This study was designed to compare the physiological left ventricular hypertrophy (LVH) induced by voluntary exercise with LVH induced by aortic constriction and to determine whether calcineurin participates in the signaling of exercise-induced LVH. METHODS AND RESULTS: Wistar rats were assigned to 1 of the following 5 groups: 10 weeks of voluntary exercise (EX), a sedentary regimen, a 1-week (AC1) or 4-week (AC4) ascending aortic constriction period, or a sham operation. EX rats ran 2.4+/-0.7 km/day voluntarily in specially manufactured cages; this was associated with an increase of LV diastolic dimension and stroke volume. Myocardial calcineurin activity markedly increased in EX rats (46.4+/-8.3 versus 18.4+/-0.5 pmol. min(-1). mg(-1) in sedentary rats; P<0.001) and in AC1 rats (44.9+/-6.7 versus 22.1+/-3.7 pmol. min(-1). mg(-1) in sham-operated rats; P<0.001), but not in AC4 rats (29.0+/-3.4 pmol. min(-1). mg(-1)). Treatment with cyclosporin A completely inhibited the development of LVH in EX rats, but it only partially attenuated the development of LVH in AC4 rats. CONCLUSIONS: Calcineurin was activated in exercise-induced physiological LVH and in the developing phase of LVH (AC1), but not in decompensated pressure-overload hypertrophy (AC4). Cyclosporin therapy for the prevention of LVH may be harmful because it does not block the development of pathological hypertrophy but rather that of favorable adaptive hypertrophy.

Animals↗
PubMed2000

Regulation of rheumatoid synovial cell growth by ceramide.

Overgrowth of rheumatoid synoviocytes, which results in joint destruction, is due to impaired balance between cell proliferation and cell death (apoptosis). Ceramide is an important lipid messenger involved in mediating a variety of cell functions including apoptosis. We investigated the effects of ceramide on growth-promoting anti-apoptotic signals in rheumatoid synovial cells. Human synovial cells isolated from patients with rheumatoid arthritis (RA) were stimulated with platelet-derived growth factor (PDGF) in the presence or absence of C2-ceramide. The kinase activity of Akt, MEK, and ERK1/2 was analyzed in PDGF-stimulated synovial cells by Western blot analysis. Pretreatment with C2-ceramide completely inhibited PDGF-induced cell cycle progression of rheumatoid synovial cells. PDGF stimulation induced phosphorylation and activation of Akt, MEK, and ERK1/2 in rheumatoid synovial cells. C2-ceramide inhibited the activation of Akt, MEK and ERK1/2 in PDGF-stimulated synovial cells. Our data demonstrated that inhibition of anti-apoptotic kinases, such as Akt and ERK1/2, may play an important role in ceramide-mediated apoptosis of rheumatoid synovial cells.

Apoptosis↗
PubMed2000

Induction of COX-2 expression by nitric oxide in rheumatoid synovial cells.

Prostaglandins formed by cyclooxygenase (COX) enzymes are important mediators of inflammation. The contribution of inducible COX-2 in the rheumatoid synovium is well documented. In this study, we evaluated the contribution of nitric oxide (NO) to COX-2 expression in rheumatoid synovial cells. Exposure of rheumatoid synovial cells to a NO donor, SNAP, induced COX-2 protein expression in a dose-dependent manner. RT-PCR analysis also demonstrated that COX-2 mRNA was induced in SNAP-treated synovial cells. Dexamethasone at therapeutic concentrations markedly inhibited this NO-mediated COX-2 expression in synovial cells. In contrast to its effect on COX-2 expression, SNAP did not affect the constitutive expression of COX-1 in rheumatoid synovial cells. Our findings suggest that NO is an important modulator of COX-2 expression and that glucocorticoids exert their anti-inflammatory action in rheumatoid synovium, at least in part, by suppression of COX-2 induction.

Arthritis, Rheumatoid↗
PubMed2000

A mouse model of vascular injury that induces rapid onset of medial cell apoptosis followed by reproducible neointimal hyperplasia.

Genetically modified mice serve as a powerful tool to determine the role of specific molecules in a wide variety of biological phenomena including vascular remodeling. Several models of arterial injury have been proposed to analyze transgenic/knock-out mice, but many questions have been raised about their reproducibility and physiological significance. Here, we report a new mouse model of vascular injury that resembles balloon-angioplasty. A straight spring wire was inserted into the femoral artery via arterioctomy in a small muscular branch. The wire was left in place for one minute to denude and dilate the artery. After the wire was removed, the muscular branch was tied off and the blood flow of the femoral artery was restored. The lumen was enlarged with rapid onset of medial cell apoptosis. While the circumference of the external elastic lamina remained enlarged, the lumen was gradually narrowed by neointimal hyperplasia composed of smooth muscle cells. At 4 weeks, a concentric and homogeneous neointimal lesion was formed reproducibly in the region where the wire had been inserted. Similar exuberant hyperplasia could be induced in all strains examined (C57BL/6J, C3H/HeJ, BALB/c, and 129/SVj). This model may be widely used to study the molecular mechanism of post-angioplasty restenosis at the genetic level.

Angioplasty, Balloon↗
PubMed2000

Inhibition of carnitine synthesis modulates protein contents of the cardiac sarcoplasmic reticulum Ca2+-ATPase and hexokinase type I in rat hearts with myocardial infarction.

It was previously reported that inhibition of carnitine synthesis by 3-(2,2,2-trimethyl-hydrazinium) propionate (MET-88) restores left ventricular (LV) systolic and diastolic function in rats with myocardial infarction (MI). Preservation of the calcium uptake function of sarcoplasmic reticulum Ca2+-ATPase (SERCA2) is one of the possible mechanisms by which MET-88 alleviates hemodynamic dysfunction. To test this hypothesis, the effects of MET-88 on protein content of SERCA2 were evaluated using the same rat model of heart failure. Myocardial protein content of hexokinase, which is one of the key enzymes of glucose utilization, was also measured. Either MET-88 (MET-88 group) or a placebo (MI group) was administered for 20 days to rats with MI induced by coronary artery ligation. The control group underwent sham surgery (no ligation) and received placebo. In LV myocardial homogenates, the myocardial SERCA2 protein content was 32% lower (p<0.05) in the MI group than in the control group. However, in the MET-88 group myocardial SERCA2 content was the same as in the control group. Hexokinase I protein content was 29 % lower (p<0.05) in the MI group compared with the control. In contrast, hexokinase II protein content did not differ significantly among the three groups. Consequently, inhibition of carnitine synthesis ameliorates depression of SERCA2 and hexokinase I protein content which may reduce tissue damage caused by MI.

Animals↗
PubMed2000

Elevated CTLA-4 expression on CD4 T cells from periodontitis patients stimulated with Porphyromonas gingivalis outer membrane antigen.

To characterize the T cell response to Porphyromonas gingivalis, we examined the expression of costimulatory molecules on T cells derived from adult periodontitis patients with high serum antibody titre to P. gingivalis. The expression of CD28, CTLA-4, CD40 ligand (CD40L) on CD4+ T cells was analysed by flow cytometry. IL-10 and transforming growth factor-beta (TGF-beta) mRNA expression were determined by reverse transcription-polymerase chain reaction (RT-PCR) and subsequent image analysis. Peripheral blood mononuclear cells (PBMC) derived from periodontitis patients showed higher proliferative responses to P. gingivalis outer membrane (OM) than those from healthy controls (P < 0.05). The percentage of CTLA-4+ cells within CD4+ T cells of patients was significantly higher than that of healthy controls after P. gingivalis OM stimulation (33.0% versus 11.9%, P < 0.01). There was no significant difference in the percentages of CD28+ cells and CD40L+ cells, and the percentage of CD40L+ cells was low in both groups even after stimulation. Stimulation of PBMC with P. gingivalis OM induced significantly higher IL-10 mRNA expression in periodontitis patients than in healthy controls (P < 0.05). The level of TGF-beta mRNA expression of patients tended to be higher than that of healthy controls, but there was no significant difference. To elucidate the functional role of CTLA-4, we further investigated the secondary proliferative response to P. gingivalis OM. Interestingly, P. gingivalis OM stimulation did not enhance antigen-specific secondary response. Anti-CTLA-4 MoAb had no effect on proliferation in the presence of P. gingivalis OM. CTLA-4Ig suppressed the proliferative response significantly (P < 0.01). These results suggest that T cell responses to P. gingivalis OM may be regulated by CTLA-4 that is expressed at the late phase of T cell activation, and, in part, immunosuppressive cytokines. Taken together, CTLA-4 may play a crucial role in the pathogenesis of chronic inflammatory periodontal disease.

Abatacept↗
PubMed2000

Prostate cancer with multiple lung metastases in a hemodialysis patient.

In hemodialysis patients, few cases of prostate cancer have been reported until recently. We present a case of prostate cancer with multiple lung metastases in a chronic hemodialysis patient. A 65-year-old Japanese man who had maintained hemodialysis for 5 years was referred to our hospital with multiple metastatic lung tumors. Serum prostate tumor markers were highly elevated although his plasma testosterone level was within the normal range. A transrectal needle prostate biopsy confirmed a histologic diagnosis of moderately differentiated adenocarcinoma. Androgen blockade therapy was very effective as evidenced by a quick decrease of serum tumor markers. The follow-up computed tomography scan of the chest performed 3 months later showed a complete disappearance of the coin lesions. The early detection of prostate cancer in hemodialysis patients is difficult because of a lack of urologic symptoms, which indicate the importance of periodic screening by serum tumor markers. Combined androgen blockade is effective even in hemodialysis patients. However, close follow up is necessary because long-term results and prognoses are still unknown.

Adenocarcinoma↗
PubMed2000

Effect of vitamin K2 on osteoblast apoptosis: vitamin K2 inhibits apoptotic cell death of human osteoblasts induced by Fas, proteasome inhibitor, etoposide, and staurosporine.

Vitamin K2 is used for the treatment of osteoporosis, but the precise mode of action is still not clear. We investigated the effects of vitamin K2 on apoptosis of human osteoblasts. Human osteoblastic cell line MG63 cells and human primary osteoblast-like cells obtained from bone fragments in corrective surgery were used as human osteoblasts. Cells were cultured with or without various concentrations of vitamin K2 and tumor necrosis factor-alpha (TNF-alpha). We then determined the proliferative response, expression of Fas and Bcl-2-related proteins, and Fas-mediated apoptosis of these cells induced by anti-Fas immunoglobulin M (IgM). In addition, the effect of vitamin K2 in osteoblast apoptosis induced by Z-Leu-Leu-Leu-aldehyde (LLL-CHO), etoposide, or staurosporine was also examined. Human osteoblasts did not show spontaneous apoptosis in culture, even in the presence of vitamin K2 or TNF-alpha. Furthermore, proliferation of the cells was not influenced by vitamin K2 or TNF-alpha. Fas was functionally expressed on human osteoblasts, and the treatment with TNF-alpha significantly enhanced both Fas expression and Fas-mediated apoptosis of osteoblasts. The addition of vitamin K2 to the culture resulted in a dose-dependent inhibition of functional Fas expression on osteoblasts, in the presence or absence of TNF-alpha. Treatment of human osteoblasts with vitamin K2 clearly suppressed Bax expression of the cells, although the expression of Bcl-2 was not influenced by vitamin K2. Fas ligand (FasL) cDNA transformants were cytotoxic against osteoblasts, and the cytotoxicity was increased when osteoblasts were treated with TNF-alpha. The addition of vitamin K2 to osteoblasts significantly decreased the cytotoxic effects of FasL cDNA transformants. Furthermore, apoptosis of human osteoblasts induced by LLL-CHO, etoposide, or staurosporine was also clearly suppressed in vitamin K2-treated osteoblasts. Our results suggest that vitamin K2 inhibits apoptotic cell death of osteoblasts and maintains the number of osteoblasts. These actions may explain the therapeutic efficacy of vitamin K2 in osteoporosis.

Apoptosis↗
PubMed2000

Regulation of cyclooxygenase-2 expression in human osteoblastic cells by N-acetylcysteine.

Cyclooxygenase (COX) plays a pivotal role in the inflammatory process of inflammatory arthropathies. Inflammatory cytokines induce COX-2 expression in osteoblasts of inflamed joints, followed by osteoclast activation. The inhibition of COX-2 expression could help prevent prostaglandin E2 secretion, followed by osteoclast activation for bone destruction and resorption. We examined whether the antioxidant N-acetylcysteine (NAC) inhibited COX-2 expression induced in the human osteoblastic cell line MG63 by interleukin-1beta (IL-1beta). According to Western blot and reverse transcription-polymerase chain reaction (RT-PCR) test results, NAC inhibited IL-1beta-induced COX-2 expression in protein and messenger RNA. We also demonstrated immunohistochemically that NAC inhibited NFkappaB nuclear translocation. These results suggested that NAC inhibited both COX-2 expression and NFkappaB nuclear translocation in MG63, which in turn indicated that NAC could inhibit the inflammatory process involved in bone resorption by regulating COX-2 expression at the level of transcription.

Acetylcysteine↗