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Biomedical subjects

Y Eto

Publications and source records attributed to Y Eto.

At least 55 records · Page 3Linked to original sources
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

Local adenovirus-mediated transfer of C-type natriuretic peptide suppresses vascular remodeling in porcine coronary arteries in vivo.

OBJECTIVE: This study was designed to examine whether or not adenovirus-mediated gene transfer of C-type natriuretic peptide (CNP) can prevent coronary restenotic changes after balloon injury in pigs in vivo. BACKGROUND: Gene therapy to prevent restenosis after percutaneous transluminal coronary angioplasty (PTCA) might be useful but requires a method applicable for in vivo gene delivery into the coronary artery as well as the efficient vector encoding a potent antiproliferative substance. We tested whether the adenovirus-mediated gene transfer of CNP by use of an infiltrator angioplasty balloon catheter (IABC) might prevent the coronary restenotic changes after balloon injury. METHODS: Balloon angioplasty was performed in the left anterior descending and the left circumflex coronary artery in pigs. Immediately after the balloon injury, adenovirus solution encoding either CNP (AdCACNP) or beta-galactosidase (AdCALacZ) gene was injected with IABC into the balloon-injured coronary segments. Expression of CNP was assessed by immunohistochemical staining and cyclic guanosine 3',5'-monophosphate (cGMP) measurement. Coronary restenotic changes were evaluated by both angiographic and histological examinations. RESULTS: CNP was highly expressed in the media and the adventitia of the coronary artery at the AdCACNP-transfected but not at the AdCALacZ-transfected segment. In the AdCALacZ-transfected segment, vascular cGMP levels tended to be reduced as compared with the untreated segment, whereas in the AdCACNP-transfected segment, vascular cGMP levels were restored. Angiographic coronary stenosis was significantly less at the AdCACNP-transfected than at the AdCALacZ-transfected segment. Histological examination revealed that this was achieved primarily by the marked inhibition of the geometric remodeling of the coronary artery by the CNP gene transfer. CONCLUSIONS: Adenovirus-mediated CNP gene transfer with the IABC system may be a useful gene therapy to prevent restenosis after PTCA in vivo.

Adenoviridae↗
PubMed2000

An oral CD40 ligand gene therapy against lymphoma using attenuated Salmonella typhimurium.

CD40 ligand (CD40L) has a great potential as a novel treatment for B-cell lymphoma (BCL). It has previously been demonstrated that a nonvirulent strain of Salmonella typhimurium mutant (ST) can be used not only as a vehicle in oral genetic immunization via the intestinal mucosa, but also as an enhancer of interferon gamma- and tumor necrosis factor alpha-mediated immunity. After confirming that human CD40L can up-regulate expression of Fas, B7-1, and B7-2 molecules on murine BCL cells in vitro, we transfected the human CD40L gene into S typhimurium mutant (ST40L), which was administrated orally to determine whether it was able to prevent the growth of BCL in mice. Expression of human CD40L was confirmed immunohistochemically with protein being detected in the Peyer's patches of mice immunized with ST40L. Moreover, human soluble CD40L had been detectable until 7 to 8 weeks after oral administration of ST40L. Although ST alone exhibited some protective effects, ST40L demonstrated a significantly greater protection against the development of CD40 positive BCL compared with the control. In the surviving mice that had been treated with ST40L, a small and hard nodule was formed at the injection site, which was found to be composed of infiltrating lymphocytes expressing Fas ligand. These results have the potential to be a simple, effective, and above all, safe immune-gene therapy against BCL. (Blood. 2000;95:1258-1263)

3T3 Cells↗
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

Efficiency of adenovirus-mediated gene transfer into hepatocytes by liver asanguineous perfusion method.

Efficient targeted gene delivery is essential for successful gene therapy. In this study, we examined the liver asanguineous perfusion method (LAP) for adenovirus-mediated gene transfer to the liver from the standpoints of efficiency, tissue-specificity and safety. The adenoviral vector containing the E. coli LacZ gene driven by the CAG promoter was delivered to the livers of rats by LAP. This method involves selective in situ perfusion, with the liver isolated by clamping of the afferent and efferent blood vessels to prevent adenoviral vector dissemination and genetic modification of nonhepatic organs. We demonstrated that gene transfer to the liver by LAP was not uniform, but more efficient than by intravenous (i.v.) or intraportal (i.p.) infusion, and caused no obvious liver damage or high mortality. As determined by specific histochemical staining and polymerase chain reaction, the amount of vector DNA transferred to the nonhepatic organs by LAP was significantly less than that transferred by the other two methods. Our data suggest that LAP is clearly superior to i.v. or i.p. infusion in terms of efficiency, specificity and safety of gene delivery to the liver. Further reduction in surgical risk is needed for the clinical application of gene therapy.

Adenoviridae↗
PubMed2000

End-tidal CO2 pressure decreases during exercise in cardiac patients: association with severity of heart failure and cardiac output reserve.

OBJECTIVES: We measured end-tidal CO2 pressure (PETCO2) during exercise and investigated the relationship between PETCO2 and exercise capacity, ventilatory parameters and cardiac output to determine the mechanism(s) of changes in this parameter. BACKGROUND: It is unclear whether PETCO2 is abnormal at rest and during exercise in cardiac patients. METHODS: Cardiac patients (n = 112) and normal individuals (n = 29) performed exercise tests with breath-by-breath gas analysis, and measurement of cardiac output and arterial blood gases. RESULTS: PETCO2 was lower in patients than in normal subjects at rest and decreased as the New York Heart Association class increased, whereas the partial pressure of arterial CO2 did not differ among groups. Although PETCO2 increased during exercise in patients, it remained lower than in normal subjects. PETCO2 in relation to cardiac output was similar in patients and normal subjects. PETCO2 at the respiratory compensation point was positively correlated with the O2 uptake (r = 0.583, p < 0.0001) and the cardiac index at peak exercise (r = 0.582, p < 0.0001), and was negatively correlated with the ratio of physiological dead space to the tidal volume. The sensitivity and specificity of PETCO2 to predict an inadequate cardiac output were 76.6% and 75%, respectively, when PETCO2 at respiratory compensation point and a cardiac index at peak exercise that were less than the respective control mean-2 SD values were considered to be abnormal. CONCLUSIONS: PETCO2 was below normal in cardiac patients at rest and during exercise. PETCO2 was correlated with exercise capacity and cardiac output during exercise, and the sensitivity and specificity of PETCO2 regarding decreased cardiac output were good. PETCO2 may be a new ventilatory abnormality marker that reflects impaired cardiac output response to exercise in cardiac patients diagnosed with heart failure.

Anaerobic Threshold↗
PubMed2000

Regional specificity of localized cortical lesions in West syndrome.

West syndrome, although classified as a generalized epilepsy, is associated with localized cerebral lesions in some cases. However, similar localized cortical abnormalities usually can result in partial epilepsy, instead of West syndrome. We performed this study to determine the additional factors that result in West syndrome instead of partial epilepsy in patients with localized cerebral lesions. We reviewed the pathologic features, topographic localization, and side of unilaterally defined cerebral lesions in relation to the seizure types in 39 epileptic patients, including five patients who presented with West syndrome. The lesions of all five patients with West syndrome involved the temporal or occipital lobes (or both). Among the nine with an occipital lesion, four had West syndrome. In the 19 with a temporal lesion, three had West syndrome. However, in the 16 patients with a frontal lesion, none exhibited epileptic spasms. In four of the five with West syndrome the lesions were on the right side; 23 had lesions on the right, 16 had them on the left. Temporo-occipital lesions and lesions on the right were related to the genesis of West syndrome, which would be in close correlation with normal brain maturation.

Brain Mapping↗
PubMed2000

Activin increases bone mass and mechanical strength of lumbar vertebrae in aged ovariectomized rats.

Activin is a member of the transforming growth factor-beta superfamily and is thought to be involved in the regulation of bone formation due to its presence in bone tissue and its osteogenic activity both in vitro and in vivo. We recently found that systemic administration of activin increased both tibial bone mass and mechanical strength in young growing rats. The present study investigated the effects of activin in aged ovariectomized (ovx) rats. Twelve-month-old Fischer rats were ovariectomized and maintained for 10 months. Recombinant human activin A (activin) or human parathyroid hormone 1-34 (PTH) was administered intramuscularly three times a week for 12 weeks. Activin (1 and 5 microg/kg) markedly increased lumbar vertebral bone mineral content and bone mineral density. Activin also increased the mechanical strength of the vertebral body, which was highly correlated to the bone mineral density of the vertebral body. The maximal response in bone mass and strength was observed at 1 microg/kg of activin, which was approximately equal to that induced by PTH at 40 microg/kg. Peripheral quantitative computed tomography revealed that activin enlarged the cross-sectional size of the vertebrae without changing the foramen area, indicating its effects on cortical shells. Histomorphometric analysis of cancellous bone of vertebral body in similar experiment showed that activin (3 microg/kg) increased bone volume and the mineralizing surface, although its effects were less than PTH. The present results indicate that low doses of activin are effective against vertebral bone loss in aged ovx rats.

Activins↗
PubMed2000

Activin release from bone coupled to bone resorption in organ culture of neonatal mouse calvaria.

Activin, a member of the transforming growth factor-beta (TGF-beta) superfamily, is present in the bone matrix and assumed to be involved in the regulation of bone formation. In the present study, we investigated whether the release of activin from bone is coupled with bone resorption. Neonatal mouse calvaria were cultured in the presence of various stimulators of bone resorption (parathyroid hormone [PTH], interleukin-1beta, prostaglandin E2) for up to 72 h, and the activin activity in the medium was measured using a specific bioassay for activin. Activin activity was accumulated in proportion to the time- and dose-dependent increase in calcium release from bone into the medium (bone resorption). An inhibition of PTH-dependent bone resorption by a bisphosphonate, disodium dichlormethane-1,1-bisphosphonic acid (Cl2MBP), completely blocked release of activin activity from bone into the medium. In primary culture of calvarial cells, however, neither PTH nor Cl2MBP affected activin production. These findings indicate that release of activin activity from bone tissue is strongly coupled to bone resorption. Because activin possesses osteogenic activities, activin released locally from bone might be involved in the regulation of bone formation in the physiological process of bone remodeling, as has been suggested for TGF-beta.

Activins↗
PubMed2000

Bone marrow transplantation for the treatment of X-linked adrenoleukodystrophy.

The effects of bone marrow transplantation (BMT) in X-linked childhood adrenoleukodystrophy (ALD) are described in four Japanese patients. Two older patients, 10-year-old boys with IQ 60 and difficulty in school, had favourable results. IQ levels and MRI findings were generally maintained after BMT. One patient showed improvement of gait disturbance. They have both attended ordinary schools after BMT, although a learning disorder persists. On the other hand, two other younger patients with a rapid course and indeterminate IQ at BMT showed deterioration of neurological functions. Indication for BMT seems to be a maintained IQ level, preferably higher than 80, since it seems to be difficult to normalize IQ level after BMT. Younger patients have higher risk of developing a rapidly progressive form of the disease. Identification of presymptomatic boys, and serial and careful follow-up by neuropsychological and neuroradiological studies, are essential prerequisites to successful BMT in X-ALD.

Adrenoleukodystrophy↗
PubMed2000

Gene therapy/cell therapy for lysosomal storage disease.

Lysosomal storage diseases (LSD) are considered to be appropriate disorders for gene therapy/cell therapy. We are attempting to treat one of these disorders using a mouse model, the Sly mouse. This is an authentic model for human beta-glucuronidase deficiency, MPS VII. We have carried out two types of experimental protocols; in vivo gene therapy and ex vivo gene therapy using Sly mice. For in vivo gene therapy, we produced a recombinant adenovirus that expresses human beta-glucuronidase and administered this to Sly mice intravenously. The beta-glucuronidase activities in liver and spleen were elevated to 40% and 20%, respectively, of the heterozygote enzyme level at day 16. Expression persisted for at least 35 days. Pathological abnormalities improved in these tissues and urinary glycosaminoglycan excretion was reduced in treated animals. Ex vivo gene therapy/cell therapy was carried out using macrophages obtained by cultivation of bone marrow cells. Non-myeloablated macrophages from normal mice were transplanted into Sly mice, and after 7 days donor cells had populated the liver and spleen. The human beta-glucuronidase (HBG) activity was increased in liver and spleen, although these enzyme activities subsequently fell by 38 days. The pathological improvement in Sly mice was evident at day 38 post transplantation. Furthermore, the macrophages from Sly mice were treated with retrovirus/adenovirus vector expressing HBG activity and the glycosaminoglycan accumulation was markedly decreased after 5 weeks. These data suggest that genetically engineered macrophage transplantation may be a very useful form of ex vivo gene therapy for lysosomal storage diseases. We also discuss the possible treatment of the CNS involvement in lysosomal storage diseases by gene therapy/cell therapy.

Animals↗
PubMed2000

Ectopic expression of c-myc fails to overcome downregulation of telomerase activity induced by herbimycin A, but ectopic hTERT expression overcomes it.

Telomerase plays a key role in the maintenance of chromosomal stability in tumors, but the mechanism regulating telomerase activity is still unclear. Recent studies have suggested that c-myc may be vital for regulation of hTERT mRNA expression and telomerase activity. In this study, we investigated the changes of telomerase activity and telomerase-related genes induced by herbimycin A in K562 human chronic myelogeous leukemic cells. Telomerase activity showed a biphasic pattern in herbimycin A-treated K562 cells. Initially, the telomerase activity decreased along with the decline of cells in S and G2/M phases, but it recovered slightly at the end of treatment. Expression of mRNA for the telomerase catalytic subunit (hTERT) was decreased before the decline of telomerase activity, and increased slightly before the reactivation of telomerase activity. During herbimycin A treatment, both c-myc and cyclin D1 mRNA showed transient downregulation before the increase of G1 cells. Herbimycin A treatment caused the downregulation of both telomerase activity and hTERT mRNA in cyclin D1-transfected K562 cells, while telomerase activity was partially restored in c-Myc-transfected cells. In contrast, hTERT-transfected K562 cells maintained a high level of telomerase activity during herbimycin A treatment. Neither the template RNA component of telomerase (hTERC) nor telomerase-associated protein (TEP-1) were altered in any of the transfected K562 cells. These results indicate that telomerase activity is mainly regulated by hTERT, and that c-Myc protein is one of the positive regulators of hTERT in leukemic cells but is not enough to counteract the downregulation of telomerase activity by herbimycin A completely.

Benzoquinones↗
PubMed2000

Morphometry of the head of the caudate nucleus in patients with velocardiofacial syndrome (del 22q11.2).

UNLABELLED: Velocardiofacial syndrome (VCFS) is a chromosomal anomaly syndrome characterized by multiple congenital malformations, including cleft palate and cardiac anomalies. Many patients have attention-deficit (hyperactivity) disorders (AD[H]D) in childhood and schizophrenia in adulthood. We reviewed cranial magnetic resonance imaging (MRI) scans with particular attention to the head of the caudate nucleus and found that in control subjects, the head of the caudate was larger on the left than on the right, whereas VCFS patients showed a reversed right > left pattern or no significant asymmetry. A similar right > left asymmetry or a lack of this asymmetry has been reported in patients with AD(H)D. CONCLUSIONS: These results suggest a common pathophysiological mechanism of behavioural and cognitive problems in patients with AD(H)D and those with VCFS.

Abnormalities, Multiple↗
PubMed2000

Gene transfer of dominant negative Rho kinase suppresses neointimal formation after balloon injury in pigs.

Restenosis after angioplasty still remains a major problem for which neointimal formation appears to play an important role. Recent studies in vitro suggested that Rho kinase, a target protein of Rho, is important in various cellular functions. We thus examined whether Rho kinase is involved in the restenotic changes after balloon injury. In vivo gene transfer was performed immediately after balloon injury in both sides of the porcine femoral arteries with adenoviral vector encoding either a dominant negative form of Rho kinase (AdDNRhoK) or beta-galactosidase (AdLacZ) as a control. One week after the transfer, immunohistochemistry confirmed the successful gene expression in the vessel wall, whereas 2 wk after the transfer, Western blotting showed the functional upregulation of Rho kinase at the AdLacZ site and its suppression at the AdDNRhoK site. Angiography showed the development of a stenotic lesion at the AdLacZ site where histological neointimal formation was noted, whereas those changes were significantly suppressed at the AdDNRhoK site. These results indicate that Rho kinase is involved in the pathogenesis of neointimal formation after balloon injury in vivo.

Angiography↗
PubMed2000

Rho-kinase is involved in macrophage-mediated formation of coronary vascular lesions in pigs in vivo.

We have previously shown that long-term treatment with an inflammatory cytokine from the adventitia causes the development of coronary vascular lesions, with the accumulation of macrophages. Recent studies in vitro have suggested that small G-protein Rho and its effector, Rho-kinase/ROK/ROCK, may be the key molecules for various cellular functions, including cell adhesion and movement. In this study, we examined whether adventitia-derived macrophages cause the formation of coronary vascular lesions in vivo and, if so, whether Rho-kinase is involved in the process. Porcine coronary segments from the adventitia were chronically treated with monocyte chemoattractant protein-1 alone, oxidized low density lipoprotein alone, or both. Vascular lesion formation (neointimal formation and development of vascular remodeling) was mostly enhanced at the coronary segment cotreated with monocyte chemoattractant protein-1 and oxidized low density lipoprotein, where the phosphorylation of myosin binding subunit of myosin phosphatase was increased, indicating an increased activity of Rho-kinase in vivo. Histological examination demonstrated that macrophages were accumulated at the adventitia and thereafter migrated into the vascular wall. Long-term oral treatment with fasudil, which is metabolized to a specific Rho-kinase inhibitor (hydroxyfasudil) after oral absorption, markedly inhibited the myosin binding subunit phosphorylation, the macrophage accumulation and migration, and the coronary lesion formation in vivo. These results indicate that Rho-kinase is involved in macrophage-mediated formation of coronary vascular lesions in our porcine model in vivo.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed2000

Purification and characterization of novel transglutaminase from Bacillus subtilis spores.

Transglutaminase activity was detected in suspensions of purified spores prepared from lysozyme-treated sporulating cells of Bacillus subtilis AJ 1307. The enzyme was easily solubilized from the spores upon incubation at pH 10.5 at 37 degrees C. The transglutaminase activity was separated into two fractions upon purification by hydrophobic interaction chromatography (TG1 and TG2). Each enzyme was purified to electrophoretic homogeneity (about 1,000-fold). Both enzymes had the same molecular weight of 29,000 as estimated by SDS-PAGE, had the same N-terminal 30 amino acid sequence, and also showed the same optimal temperature (60 degrees C) and pH (8.2). The purified enzyme catalyzed formation of cross-linked epsilon-(gamma-glutamyl)lysine isopeptides, resulting in the gel-formation of protein solutions such as alphas-casein and BSA.

Amino Acid Sequence↗