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1.
Clin Nephrol ; 69(1): 47-52, 2008 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-18218316

RESUMEN

A 63-year-old man was admitted to our hospital for evaluation of generalized edema. Coexistence of severe hypothyroidism and nephrotic syndrome was detected by laboratory examination. High titer of both antimicrosomal antibody and antithyroid peroxidase antibody indicated Hashimotoâs disease. Renal biopsy showed minimal change glomerular abnormality, but no findings of membranous nephropathy. A series of medical treatments, including steroid therapy, thyroid hormone and human albumin replacement therapy, were administered. However, acute renal failure accompanied by hypotension, was not sufficiently prevented. After 9 sessions of plasmapheresis therapy, the severe proteinuria and low serum albumin levels were improved. Even after resting hypotension was normalized, neither renal function nor thyroid function were fully recovered. After discharge, renal function gradually returned to normal, and the blood pressure developed into a hypertensive state concomitant with the normalization of thyroid function. This report is a rare case of autoimmune thyroid disease complicated with minimal change nephrotic syndrome. In most cases of nephritic syndrome, acute renal failure (ARF) has been reported to coexist with hypertension. Although pseudohypothyroidism is well-known in nephrotic pathophysiology, complications of actual hypothyroidism are uncommon. It is suggested that the development of hypotension and ARF could be enhanced not only by hypoproteinemia, but also by severe hypothyroidism.


Asunto(s)
Lesión Renal Aguda/etiología , Enfermedad de Hashimoto/complicaciones , Nefrosis Lipoidea/etiología , Lesión Renal Aguda/patología , Lesión Renal Aguda/terapia , Biopsia , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Nefrosis Lipoidea/patología , Nefrosis Lipoidea/terapia , Plasmaféresis/métodos
2.
J Clin Invest ; 99(12): 2898-905, 1997 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-9185513

RESUMEN

We described recently the activation of the Janus kinasesignal transducer and activator of transcription (JakSTAT) and mitogen-activated protein (MAP) kinase pathways by leukemia inhibitory factor (LIF) through gp130, a signal transducer of IL-6-related cytokines, that transduces hypertrophic signals in cardiac myocytes. In addition, stimulation of gp130 by IL-6-related cytokines is known to exert a cytoprotective effect. In the present study, we investigated the possibility that activation of gp130 initiates activation of the cytoprotective genes in cardiac myocytes. Incubation of cardiac myocytes with LIF induced the expression of bcl-x, and the isoform that was induced by LIF was identified as bcl-xL. Induction of bcl-xL protein was also identified by Western blotting. Antisense oligonucleotide against bcl-x mRNA inhibited protective effect of LIF accompanied with the reduction in bclxL protein. We constructed bcl-x promoter-luciferase reporter gene plasmids (-639/+10- or -161/+10-luciferase), and transfected them to cardiac myocytes. LIF stimulation increased the luciferase activity of -639/+10-luciferase plasmids. Although -161/+10-luciferase plasmids presented comparable responsiveness to LIF, the basal transcription level was impaired. The LIF-responsive cis-element was localized to a DNA fragment (positions -161 to +10) that contains an interferon-gamma activation site (GAS) motif (GGA) at position -41 of the bcl-x gene promoter. This motif bound to STAT1, not to STAT3, and site-directed mutagenesis revealed that this motif was essential for LIF-responsive promoter activity. These data suggest that LIF induces bcl-x mRNA via STAT1 binding cis-element in cardiac myocytes, presenting cytoprotective effect.


Asunto(s)
Antígenos CD/fisiología , Proteínas de Unión al ADN/metabolismo , Regulación de la Expresión Génica , Interleucina-6 , Glicoproteínas de Membrana/fisiología , Miocardio/metabolismo , Proteínas Proto-Oncogénicas c-bcl-2 , Proteínas Proto-Oncogénicas/genética , Transducción de Señal , Transactivadores/metabolismo , Animales , Animales Recién Nacidos , Células Cultivadas , Receptor gp130 de Citocinas , ADN/metabolismo , Inhibidores de Crecimiento/farmacología , Factor Inhibidor de Leucemia , Linfocinas/farmacología , Ratones , Norepinefrina/farmacología , Regiones Promotoras Genéticas , ARN Mensajero/biosíntesis , Ratas , Ratas Sprague-Dawley , Proteínas Recombinantes , Factor de Transcripción STAT1 , Proteína bcl-X
3.
J Clin Invest ; 106(4): 493-9, 2000 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-10953024

RESUMEN

The serine/threonine protein kinase Akt (protein kinase B) phosphorylates endothelial cell nitric oxide synthase (eNOS) and enhances its ability to generate nitric oxide (NO). Because NO is an important regulator of vasomotor tone, we investigated whether Akt can regulate endothelium-dependent vasomotion in vivo using a rabbit femoral artery model of gene transfer. The endothelium of isolated femoral arteries was infected with replication-defective adenoviral constructs expressing beta-galactosidase, constitutively-active Akt (myr-Akt), or dominant-negative Akt (dn-Akt). Femoral arteries transduced with myr-Akt showed a significant increase in resting diameter and blood flow, as assessed by angiography and Doppler flow measurements, respectively. L-NAME, an eNOS inhibitor, blocked myr-Akt-mediated vasodilatation. In contrast, endothelium-dependent vasodilatation in response to acetylcholine was attenuated in vessels transduced with dn-Akt, although these vessels showed normal responses to nitroglycerin, an endothelium-independent vasodilator. Similarly, relaxation of murine aorta ex vivo in response to acetylcholine, but not nitroglycerin, was inhibited by transduction of dn-Akt to the endothelium. These data provide evidence that Akt functions as key regulator of vasomotor tone in vivo.


Asunto(s)
Endotelio Vascular/fisiología , Óxido Nítrico/fisiología , Proteínas Serina-Treonina Quinasas , Proteínas Proto-Oncogénicas/fisiología , Vasodilatación/fisiología , Acetilcolina/farmacología , Adenoviridae/genética , Animales , Endotelio Vascular/efectos de los fármacos , Endotelio Vascular/enzimología , Arteria Femoral/fisiología , Técnicas de Transferencia de Gen , Técnicas In Vitro , Ratones , Ratones Endogámicos C57BL , Nitroglicerina/farmacología , Proteínas Proto-Oncogénicas/genética , Proteínas Proto-Oncogénicas c-akt , Conejos , Vasodilatación/efectos de los fármacos , Vasodilatadores/farmacología
4.
J Clin Invest ; 106(8): 1011-20, 2000 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-11032861

RESUMEN

Vascular smooth muscle cells (VSMCs) at capacitance arteries of hypertensive individuals and animals undergo marked age- and blood pressure-dependent polyploidization and hypertrophy. We show here that VSMCs at capacitance arteries of rat models of hypertension display high levels of Akt1/PKB protein and activity. Gene transfer of Akt1 to VSMCs isolated from a normotensive rat strain was sufficient to abrogate the activity of the mitotic spindle cell-cycle checkpoint, promoting polyploidization and hypertrophy. Furthermore, the hypertrophic agent angiotensin II induced VSMC polyploidization in an Akt1-dependent manner. These results demonstrate that Akt1 regulates ploidy levels in VSMCs and contributes to vascular smooth muscle polyploidization and hypertrophy during hypertension.


Asunto(s)
Hipertensión/genética , Músculo Liso Vascular/patología , Poliploidía , Proteínas Serina-Treonina Quinasas/biosíntesis , Proteínas Proto-Oncogénicas , Angiotensina II/farmacología , Animales , Aorta/patología , Hipertensión/patología , Hipertrofia , Arterias Mesentéricas/patología , Músculo Liso Vascular/citología , Mutágenos/farmacología , Proteínas Serina-Treonina Quinasas/genética , Proteínas Proto-Oncogénicas c-akt , Ratas , Ratas Endogámicas SHR , Ratas Endogámicas WKY , Ratas Zucker , Proteínas Recombinantes/biosíntesis , Regulación hacia Arriba
5.
Mol Cell Biol ; 19(7): 5073-82, 1999 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-10373556

RESUMEN

During myogenesis, proliferating myoblasts withdraw from the cell cycle, acquire an apoptosis-resistant phenotype, and differentiate into myotubes. Previous studies indicate that myogenic induction of the cyclin-dependent kinase inhibitor p21 results in an inhibition of apoptotic cell death in addition to its role as a negative cell cycle regulator. Here we demonstrate that the protein encoded by the Akt proto-oncogene is induced in C2C12 cells during myogenic differentiation with a corresponding increase in kinase activity. In differentiating cultures, expression of dominant-negative forms of Akt increase the frequency of cell death whereas expression of wild-type Akt protects against death, indicating that Akt is a positive modulator of myocyte survival. Antisense oligonucleotides against p21 block cell cycle withdrawal, inhibit Akt induction, and enhance cell death in differentiating myocyte cultures. Adenovirus-mediated transfer of wild-type or constitutively active Akt constructs confer partial resistance to cell death under conditions where cell cycle exit is blocked by the antisense oligonucleotides. Collectively, these data indicate that cell cycle withdrawal facilitates the induction of Akt during myogenesis, promoting myocyte survival.


Asunto(s)
Ciclo Celular , Músculos/citología , Proteínas Serina-Treonina Quinasas , Proteínas Proto-Oncogénicas/metabolismo , Adenovirus Humanos , Animales , Diferenciación Celular , Línea Celular , Supervivencia Celular , Inhibidor p21 de las Quinasas Dependientes de la Ciclina , Ciclinas/metabolismo , Técnicas de Transferencia de Gen , Vectores Genéticos , Ratones , Mitosis , Proteínas Tirosina Quinasas , Proto-Oncogenes Mas , Proteínas Proto-Oncogénicas/genética , Proteínas Proto-Oncogénicas c-akt , Regulación hacia Arriba
6.
Circulation ; 101(6): 660-7, 2000 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-10673259

RESUMEN

BACKGROUND: IGF-1 has been shown to protect myocardium against death in animal models of infarct and ischemia-reperfusion injury. In the present study, we investigated the role of the IGF-1-regulated protein kinase Akt in cardiac myocyte survival in vitro and in vivo. METHODS AND RESULTS: IGF-1 promoted survival of cultured cardiomyocytes under conditions of serum deprivation in a dose-dependent manner but had no effect on cardiac fibroblast survival. The cytoprotective effect of IGF-1 on cardiomyocytes was abrogated by the phosphatidylinositol 3-kinase (PI 3-kinase) inhibitor wortmannin. Wortmannin had no effect on cardiomyocyte viability in the absence of IGF-1. IGF-1-mediated cytoprotection correlated with the wortmannin-sensitive induction of Akt protein kinase activity. To examine the functional consequences of Akt activation in cardiomyocyte survival, replication-defective adenoviral constructs expressing wild-type, dominant-negative, and constitutively active Akt genes were constructed. Transduction of dominant-negative Akt blocked IGF-1-induced survival but had no effect on cardiomyocyte survival in the absence of IGF-1. In contrast, transduction of wild-type Akt enhanced cardiomyocyte survival at subsaturating levels of IGF-1, whereas constitutively active Akt protected cardiomyocytes from apoptosis in the absence of IGF-1. After transduction into the mouse heart in vivo, constitutively active Akt protected against myocyte apoptosis in response to ischemia-reperfusion injury. CONCLUSIONS: These data are the first documentation that Akt functions to promote cellular survival in vivo, and they indicate that the activation of this pathway may be useful in promoting myocyte survival in the diseased heart.


Asunto(s)
Factor I del Crecimiento Similar a la Insulina/farmacología , Daño por Reperfusión Miocárdica/metabolismo , Miocardio/metabolismo , Proteínas Serina-Treonina Quinasas/metabolismo , Proteínas Proto-Oncogénicas/metabolismo , Transducción de Señal , Animales , Supervivencia Celular/efectos de los fármacos , Células Cultivadas , Ratones , Ratones Endogámicos C57BL , Daño por Reperfusión Miocárdica/tratamiento farmacológico , Daño por Reperfusión Miocárdica/patología , Miocardio/patología , Proteínas Serina-Treonina Quinasas/genética , Proteínas Proto-Oncogénicas/genética , Proteínas Proto-Oncogénicas c-akt , Transducción de Señal/efectos de los fármacos
7.
Circulation ; 103(4): 555-61, 2001 Jan 30.
Artículo en Inglés | MEDLINE | ID: mdl-11157722

RESUMEN

BACKGROUND: We recently reported that the activation of glycoprotein (gp) 130 by leukemia inhibitory factor (LIF) upregulates Bcl-xL and exerts antiapoptotic effects in cardiac myocytes. In addition, LIF induces activation of phosphatidylinositol (PI) 3-kinase and Akt, which are known to be required for cell survival. However, their regulatory roles in cell death remain unknown. METHODS AND RESULTS: We investigated the fate of these proteins and the cytoprotective effects of LIF on doxorubicin (DOX)-induced apoptosis in cultured neonatal rat cardiac myocytes. Myocyte apoptosis increased significantly in DOX-treated cells but was significantly reduced by LIF pretreatment. The kinase activities of PI 3-kinase and Akt declined below basal levels but were partially recovered with LIF. Moreover, DOX-induced caspase-3 activation and decrease in Bcl-xL abundance are completely inhibited by LIF and caspase inhibitor. LIF phosphorylates Bad through PI 3-kinase and reduces the heterodimerization of Bad with Bcl-xL. Adenovirus transfer of the constitutively active form of Akt to cardiac myocytes restored cardiac myocyte survival after DOX treatment. Conversely, the dominant-negative form of Akt inhibited LIF-induced increase in cell viability and suppression of caspase-9 activation. CONCLUSIONS: Activation of gp130 inhibits DOX-induced cell death in cardiac myocytes, resulting in the restoration of PI 3-kinase/Akt activities and in the inactivation of caspase-3, leading to facilitation of the protective function of Bcl-xL.


Asunto(s)
Antígenos CD/metabolismo , Apoptosis/efectos de los fármacos , Doxorrubicina/farmacología , Enzimas/metabolismo , Ventrículos Cardíacos/efectos de los fármacos , Interleucina-6 , Glicoproteínas de Membrana/metabolismo , Proteínas Serina-Treonina Quinasas , Animales , Animales Recién Nacidos , Proteínas Portadoras/metabolismo , Caspasa 3 , Caspasas/metabolismo , Supervivencia Celular/efectos de los fármacos , Células Cultivadas , Receptor gp130 de Citocinas , Fragmentación del ADN/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Activación Enzimática/efectos de los fármacos , Inhibidores de Crecimiento/farmacología , Ventrículos Cardíacos/citología , Ventrículos Cardíacos/metabolismo , Etiquetado Corte-Fin in Situ , Factor Inhibidor de Leucemia , Subunidad alfa del Receptor del Factor Inhibidor de Leucemia , Linfocinas/farmacología , Fosfatidilinositol 3-Quinasas/metabolismo , Fosforilación/efectos de los fármacos , Unión Proteica , Proteínas Proto-Oncogénicas/metabolismo , Proteínas Proto-Oncogénicas c-akt , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , Ratas , Ratas Sprague-Dawley , Receptores de Citocinas/metabolismo , Receptores OSM-LIF , Proteína Letal Asociada a bcl , Proteína bcl-X
8.
Circulation ; 104(9): 979-81, 2001 Aug 28.
Artículo en Inglés | MEDLINE | ID: mdl-11524388

RESUMEN

BACKGROUND: Mice with cardiac-specific overexpression of signal transducer and activator of transcription 3 (STAT3) are resistant to doxorubicin-induced damage. The STAT3 signal may be involved in the detoxification of reactive oxygen species (ROS). METHODS AND RESULTS: The effects of leukemia inhibitory factor (LIF) or adenovirus-mediated transfection of constitutively activated STAT3 (caSTAT3) on the intracellular ROS formation induced by hypoxia/reoxygenation (H/R) were examined using rat neonatal cardiomyocytes. Either LIF treatment or caSTAT3 significantly suppressed the increase of H/R-induced ROS evaluated by 2',7'-dichlorofluorescin diacetate fluorescence. To assess whether ROS are really involved in H/R-induced cardiomyocyte injury, the amount of creatine phosphokinase in cultured medium was examined. Both LIF treatment and caSTAT3 significantly decreased H/R-induced creatine phosphokinase release. These results indicate that the gp130/STAT3 signal protects H/R-induced cardiomyocyte injury by scavenging ROS generation. To investigate the mechanism of scavenging ROS, the effects of LIF on the induction of antioxidant enzymes were examined. LIF treatment significantly increased the expression of manganese superoxide dismutase (MnSOD) mRNA, whereas the expression of the catalase and glutathione peroxidase genes were unaffected. This induction of MnSOD mRNA expression was completely blocked by adenovirus-mediated transfection of dominant-negative STAT3. Moreover, caSTAT3 augmented MnSOD mRNA and its enzyme activity. In addition, the antisense oligodeoxyribonucleotide to MnSOD significantly inhibited both LIF and caSTAT3-mediated protective effects. CONCLUSIONS: The activation of STAT3 induces a protective effect on H/R-induced cardiomyocyte damage, mainly by inducting MnSOD. The STAT3-mediated signal is proposed as a therapeutical target of ROS-induced cardiomyocyte injury.


Asunto(s)
Proteínas de Unión al ADN/metabolismo , Interleucina-6 , Miocardio/metabolismo , Estrés Oxidativo , Superóxido Dismutasa/metabolismo , Transactivadores/metabolismo , Animales , Animales Recién Nacidos , Células Cultivadas , Proteínas de Unión al ADN/genética , Regulación Enzimológica de la Expresión Génica/efectos de los fármacos , Inhibidores de Crecimiento/farmacología , Factor Inhibidor de Leucemia , Linfocinas/farmacología , Miocardio/citología , Estrés Oxidativo/efectos de los fármacos , Oxígeno/farmacología , ARN Mensajero/efectos de los fármacos , ARN Mensajero/genética , ARN Mensajero/metabolismo , Ratas , Ratas Sprague-Dawley , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/metabolismo , Factor de Transcripción STAT3 , Superóxido Dismutasa/genética , Transactivadores/genética , Regulación hacia Arriba/efectos de los fármacos
9.
Cell Death Differ ; 8(12): 1207-12, 2001 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-11753568

RESUMEN

Akt2, a homolog of Akt1, encodes a serine/threonine protein kinase that is amplified in ovarian and pancreatic cancers. The antiapoptotic activities of the Akt1 proto-oncogene product have been well documented, but the role of Akt2 in cellular survival is poorly understood. Here, we demonstrate that Akt2 mRNA, protein and kinase activity are upregulated during serum deprivation-induced C2C12 cell myogenic differentiation, a process that is associated with the acquisition of an apoptosis-resistant phenotype. Transient transfection of plasmids encoding wild-type and constitutively-active Akt2 conferred resistance against apoptosis in differentiating C2C12 cells, while a kinase-negative Akt2 construct did not. Adenovirus-mediated transfer of the constitutively-active Akt2 cDNA also suppressed apoptosis during serum deprivation-induced myogenic differentiation and it protected cells from apoptosis induced by cell detachment. These data indicate that Akt2 functions as an anti-apoptotic gene during cellular differentiation, a property that may contribute to its oncogenicity.


Asunto(s)
Anoicis , Apoptosis , Desarrollo de Músculos/fisiología , Fosfotransferasas/biosíntesis , Fosfotransferasas/efectos de los fármacos , Proteínas Serina-Treonina Quinasas , Proteínas Proto-Oncogénicas/biosíntesis , Diferenciación Celular , Células Cultivadas , Medio de Cultivo Libre de Suero , Fosfotransferasas/metabolismo , Proteínas Proto-Oncogénicas/genética , Proteínas Proto-Oncogénicas c-akt , Transfección , Regulación hacia Arriba
10.
Cardiovasc Res ; 30(6): 899-904, 1995 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-8746204

RESUMEN

OBJECTIVE: Disarrangement of cardiomyocytes is a pathological characteristic of dilated cardiomyopathy. Hereditary cardiomyopathic hamster Bio 14.6, a model of dilated cardiomyopathy, displays disorder of cardiomyocyte arrangement. The aim of this study was to analyse the disturbance of cell alignment from the point of view of the cell-cell adhesion system in Bio 14.6. METHOD: Cardiomyopathic hamster Bio 14.6 was used as a model of dilated cardiomyopathy. Histological study was performed by light and electron microscopy. Disorder of the adherens junction-specific cell-adhesion molecule (A-CAM) was analysed by immunofluorescent microscopy and immunoblotting with anti-A-CAM antibody. RESULTS: Hematoxylin-eosin staining revealed that intercalated disks were identifiable less clearly in cardiomyopathy than in a normal cardiac muscle. It was disclosed by electron microscopy that cardiomyocytes adhered to each other with reduction in subsarcolemmal electron density at intercalated disks in Bio 14.6 compared with normal hamsters. We examined the localization of the A-CAM molecule in heart by immunofluorescent microscopy. In contrast to normal cardiac samples, fluorescence was weak in intensity and unclearly demarcated in the Bio 14.6 hamsters. We measured the content of A-CAM in the heart. In Bio 14.6 hamsters, the content of A-CAM was 60 +/- 11% of that measured in normal adult hamsters. A-CAM was reduced to a lesser extent (81 +/- 12%) in the newborn hamsters. CONCLUSIONS: In Bio 14.6 hamster, structural disturbance of the intercalated disks was found on histological examination of the heart. Biochemically, A-CAM, which plays a role in intercellular adhesion in intercalated disk areas, decreased significantly. These results suggest that cardiomyopathy may be accompanied by structural disruption of cell-cell adhesion in intercalated disk regions, which may lead to the pathological feature of disarranged cardiomyocytes.


Asunto(s)
Cardiomiopatía Dilatada/patología , Adhesión Celular , Miocardio/patología , Animales , Antígenos CD , Cadherinas , Cardiomiopatía Dilatada/fisiopatología , Moléculas de Adhesión Celular/análisis , Células Cultivadas , Cricetinae , Modelos Animales de Enfermedad , Corazón/fisiopatología , Immunoblotting , Microscopía Electrónica , Microscopía Fluorescente , Miocardio/química
11.
Cardiovasc Res ; 42(1): 104-12, 1999 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-10435001

RESUMEN

OBJECTIVES: We have previously reported that interleukin (IL)-6 is induced by hypoxic stimulation in cardiac myocytes. In the present study, we examined the induction of potent transcription factors of IL-6, nuclear factor (NF)-kappa B and NF-IL6, in cardiac myocytes subjected to hypoxia. METHODS: Five different lengths of IL-6 promoter-luciferase reporter plasmids and three mutant plasmids, in which the binding sites of NF-kappa B and/or NF-IL6 were disrupted, were transfected into neonatal rat cardiac myocytes. Luciferase activities after hypoxic stimulation were measured. Electrophoretic mobility shift assays were performed using oligonucleotides containing the binding site for NF-kappa B or NF-IL6 as a probe. RESULTS: Hypoxic stimulation for 4 h increased luciferase activity by 5.7 fold in -179/+12-luciferase reporter plasmid, whereas no significant increase was observed in -60/+12-luciferase plasmid. Decrease in luciferase activity was more prominent when the NF-kappa B binding site was disrupted rather than when the NF-IL6 binding site was disrupted. Moreover, when both sites were disrupted, luciferase activity increased only by 1.5 fold. Electrophoretic mobility shift assays demonstrated enhanced binding activity to oligonucleotides containing the NF-kappa B binding site in hypoxic cardiac myocytes, which displayed a supershift with antibody to its subunit, p50 or p65. The binding activity to the NF-IL6 probe also enhanced and displayed a supershift with antibody to NF-IL6. CONCLUSIONS: Although hypoxic stimulation induced NF-kappa B and NF-IL6 in cardiac myocytes, NF-kappa B may be the primary positive regulator of transcriptional activation of the IL-6 gene in the context of hypoxia.


Asunto(s)
Regulación de la Expresión Génica , Hipoxia/inmunología , Interleucina-6/genética , Miocardio/inmunología , FN-kappa B/metabolismo , Animales , Sitios de Unión , Northern Blotting , Proteínas Potenciadoras de Unión a CCAAT , Células Cultivadas , Proteínas de Unión al ADN/metabolismo , Electroforesis , Luciferasas/metabolismo , Proteínas Nucleares/metabolismo , Plásmidos , Ratas , Transfección
12.
J Biochem ; 106(3): 455-9, 1989 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-2606897

RESUMEN

In a previous study, we identified a new mammalian myosin heavy chain, termed myosin I heavy chain-like protein (MIHC), by molecular cloning of a bovine intestinal cDNA clone. In this investigation, we examined the relationship between MIHC and the 110-kDa intestinal brush-border protein, which possesses a myosin-like ATPase activity. We raised antibodies against a chemically synthesized oligopeptide representing a part of the MIHC sequence. These antibodies reacted specifically in immunoblots with the 110-kDa protein in both purified 110-kDa protein-calmodulin complex and crude microvillar protein extracts. Staining of tissue sections with these antibodies was specifically localized to the brush-border microvilli of small intestines, indicating an identical cellular localization for both MIHC and the 110-kDa protein. Furthermore, analysis of the MIHC sequence revealed two putative calmodulin-binding sites, which is consistent with the fact that the 110-kDa protein forms a complex with calmodulin. These results strongly support the conclusion that MIHC is identical to the 110-kDa protein and suggest that not only the conventional myosin system but also the MIHC (110-kDa protein)-calmodulin complex may play an important role in ATP-dependent and Ca2+-induced brush-border contraction.


Asunto(s)
Proteínas/inmunología , Acanthamoeba , Secuencia de Aminoácidos , Animales , Calmodulina/metabolismo , Proteínas de Unión a Calmodulina/metabolismo , Pollos , Sueros Inmunes/inmunología , Immunoblotting , Inmunohistoquímica , Datos de Secuencia Molecular , Estructura Molecular , Cadenas Pesadas de Miosina , Miosina Tipo I , Relación Estructura-Actividad
13.
J Appl Physiol (1985) ; 91(4): 1574-81, 2001 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-11568138

RESUMEN

Laminar shear stress activates c-Jun NH(2)-terminal kinase (JNK) by the mechanisms involving both nitric oxide (NO) and phosphatidylinositide 3-kinase (PI3K). Because protein kinase B (Akt), a downstream effector of PI3K, has been shown to phosphorylate and activate endothelial NO synthase, we hypothesized that Akt regulates shear-dependent activation of JNK by stimulating NO production. Here, we examined the role of Akt in shear-dependent NO production and JNK activation by expressing a dominant negative Akt mutant (Akt(AA)) and a constitutively active mutant (Akt(Myr)) in bovine aortic endothelial cells (BAEC). As expected, pretreatment of BAEC with the PI3K inhibitor (wortmannin) prevented shear-dependent stimulation of Akt and NO production. Transient expression of Akt(AA) in BAEC by using a recombinant adenoviral construct inhibited the shear-dependent stimulation of NO production and JNK activation. However, transient expression of Akt(Myr) by using a recombinant adenoviral construct did not induce JNK activation. This is consistent with our previous finding that NO is required, but not sufficient on its own, to activate JNK in response to shear stress. These results and our previous findings strongly suggest that shear stress triggers activation of PI3K, Akt, and endothelial NO synthase, leading to production of NO, which (along with O(2-), which is also produced by shear) activates Ras-JNK pathway. The regulation of Akt, NO, and JNK by shear stress is likely to play a critical role in its antiatherogenic effects.


Asunto(s)
Proteínas Quinasas Activadas por Mitógenos/metabolismo , Óxido Nítrico/biosíntesis , Proteínas Serina-Treonina Quinasas , Proteínas Proto-Oncogénicas/fisiología , Infecciones por Adenoviridae/enzimología , Animales , Aorta Torácica/citología , Aorta Torácica/efectos de los fármacos , Aorta Torácica/fisiología , Western Blotting , Bovinos , Células Cultivadas , Endotelio Vascular/efectos de los fármacos , Endotelio Vascular/fisiología , Proteínas Quinasas JNK Activadas por Mitógenos , Fosfatidilinositol 3-Quinasas/metabolismo , Fosforilación , Proteínas Proto-Oncogénicas c-akt , Reología
14.
J Exp Biol ; 201 (Pt 22): 3031-40, 1998 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-9787123

RESUMEN

Immunolocalization of the -subunit of Na+/K+-ATPase was examined in the gill epithelium of chum salmon (Oncorhynchus keta) fry during acclimation to brackish water (25 salinity) and reintroduction to fresh water. In freshwater fish, strong immunoreactivity was associated with the large spherical cells located on the free surface of the primary lamellae, especially in those found at the base of the secondary lamellae, and with the large spherical cells located on the secondary lamellae.The large spherical cells located near the central venous sinus at the base of the secondary lamellae and in the interlamellar regions, however, showed little or no immunoreactivity. When freshwater fish were acclimated to brackish water, immunoreactivity developed in the large spherical cells near the central venous sinus concomitant with an increase in the hypo-osmoregulatory ability of the fish. In contrast, reintroduction from brackish water to fresh water caused the disappearance of the immunoreactivity in the large spherical cells near the central venous sinus and a reduction in hypo-osmoregulatory ability. During acclimation to brackish water and reintroduction to fresh water, the hypo-osmoregulatory ability of the fish did not correlate with the total number of large spherical cells located on the primary lamellae but was closely correlated with the number of large spherical cells showing strong immunoreactivity for Na+/K+-ATPase. We conjecture that these immunopositive large spherical cells are mature differentiated chloride cells, whereas the immunonegative large spherical cells are young developing chloride cells. The development of immunoreactivity for Na+/K+-ATPase in young chloride cells may be one of the most important factors in the development of hypo-osmoregulatory ability by chum salmon fry.

15.
Heart ; 76(1): 63-5, 1996 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-8774330

RESUMEN

OBJECTIVE: The disease-bearing genes for hypertrophic cardiomyopathy (HCM) in HCM families have been identified as the beta-myosin heavy chain, alpha-tropomyosin, and cardiac troponin T genes. Three HCM kindreds with three distinct point mutations in the alpha-tropomyosin gene had extensive clinical evaluations. DESIGN AND RESULTS: Single-strand conformation polymorphism gel analysis of polymerase chain reaction amplified products was used to capture each of the nine exons from the alpha-tropomyosin gene to identify mutations in 60 familial HCM patients. Two missense mutations in exon 2 (Ala63Val and Lys70Thr) and one missense mutation in exon 5 (Asp175Asn) were found in three unrelated HCM kindreds. These kindreds were the subject of clinical, electrocardiographic and echocardiographic studies. The morphological appearance of HCM was similar in the three kindreds. All the patients had severe hypertrophy of the left ventricle with asymmetrical septal hypertrophy during the early stage of the disease, which gradually progressed to dilatation of the left ventricle. Moreover, these kindreds showed similar disease penetrance, age of onset, and incidence of premature sudden death. The disease in these kindreds was severe and resulted in frequent sudden deaths. CONCLUSIONS: Among Japanese patients with familial HCM mutations in the alpha-tropomyosin gene are not as rare as reported, accounting for about 5% of all cases. These mutations are characterised by hypertrophy of the left ventricle which then progresses to dilatation and a high incidence of sudden or disease-related death.


Asunto(s)
Cardiomiopatía Hipertrófica/genética , Mutación Puntual , Tropomiosina/genética , Adulto , Femenino , Humanos , Hipertrofia Ventricular Izquierda/genética , Japón , Masculino , Persona de Mediana Edad , Linaje , Análisis de Secuencia de ADN
16.
Zoolog Sci ; 15(1): 35-41, 1998 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-9615616

RESUMEN

The relationships of salinity tolerance to immunolocalization of Na+,K(+)-ATPase in the gill epithelium were examined during seawater and freshwater adaptation of the guppy. In fresh water, immunoreactivity for Na+,K(+)-ATPase appeared in two types of chloride cells, which are located on the primary lamellae of the gills. Immunoreactivity was strong in the chloride cells located at the base of the secondary lamellae and weak in the chloride cells located at the interlamellar region. During seawater adaptation, the strongly-immunoreactive chloride-cells increased in number and size while the weakly-immunoreactive chloride-cells decreased in number with an increase in salinity tolerance. In the fish of the seawater-adapted strain, on the other hand, most of the chloride cells were located at the base of the secondary lamellae and showed strong immunoreactivity. During freshwater adaptation, the strongly-immunoreactive chloride-cells decreased in number and size while the weakly-immunoreactive chloride-cells increased in number with a decrease in salinity tolerance. A positive correlation was observed between the salinity tolerance and the occupying area of the strongly-immunoreactive chloride-cells while a negative correlation was observed between the salinity tolerance and the occupying area of the weakly-immunoreactive chloride-cells during the seawater and freshwater adaptation. These results directly suggested that not only the occupying area of chloride cells but also the expression of Na+,K(+)-ATPase protein in the cells is important with respect to the osmoregulatory function in the gills and hypoosmoregulatory ability at the individual level.


Asunto(s)
Poecilia/fisiología , ATPasa Intercambiadora de Sodio-Potasio/metabolismo , Equilibrio Hidroelectrolítico/fisiología , Adaptación Fisiológica , Animales , Agua Dulce , Branquias/fisiología , Inmunohistoquímica , Agua de Mar , ATPasa Intercambiadora de Sodio-Potasio/inmunología
18.
Cutis ; 56(5): 281-2, 1995 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-8565614

RESUMEN

Reports of dermatofibrosarcoma protuberans on a toe are extremely rare. It frequently occurs on the trunk and extremities. A Japanese woman presented with a dark-brownish hyperkeratotic plaque on the dorsal skin of her first toe. The initial clinical diagnosis of verruca vulgaris prompted treatment with cryotherapy. After that a glossy milky-white tumor appeared. Only the results of the histopathologic examination resulted in a diagnosis of dermatofibrosarcoma protuberans. The unusual macroscopic finding was considered to be due to repetitive stimulation by foot movement.


Asunto(s)
Dermatofibrosarcoma/patología , Enfermedades del Pie/patología , Neoplasias Cutáneas/patología , Dedos del Pie/patología , Diagnóstico Diferencial , Femenino , Humanos , Hiperpigmentación/patología , Japón , Queratosis/patología , Persona de Mediana Edad , Verrugas/patología
19.
Stud Health Technol Inform ; 52 Pt 1: 311-4, 1998.
Artículo en Inglés | MEDLINE | ID: mdl-10384469

RESUMEN

In order to determine whether a super high definition (SHD) image running at a series of 2048 resolution x 2048 line x 60 frame/sec was capable of telemedicine, we established a filing system for medical images and two experiments for transmission of high quality images were performed. All images of various types, produced from one case of ischemic heart disease were digitized and registered into the filing system. Images consisted of plain chest x-ray, electrocardiogram, ultrasound cardiogram, cardiac scintigram, coronary angiogram, left ventriculogram and so on. All images were animated and totaled a number of 243. We prepared a graphic user interface (GUI) for image retrieval based on the medical events and modalities. Twenty one cardiac specialists evaluated quality of the SHD images to be somewhat poor compared to the original pictures but sufficient for making diagnoses, and effective as a tool for teaching and case study purposes. The system capability of simultaneously displaying several animated images was especially deemed effective in grasping comprehension of diagnosis. Efficient input methods and creating capacity of filing all produced images are future issue. Using B-ISDN network, the SHD file was prefetched to the servers at Kyoto University Hospital and BBCC (Bradband ISDN Business chance & Culture Creation) laboratory as an telemedicine experiment. Simultaneous video conference system, the control of image retrieval and pointing function made the teleconference successful in terms of high quality of medical images, quick response time and interactive data exchange.


Asunto(s)
Redes de Comunicación de Computadores/instrumentación , Gráficos por Computador , Procesamiento de Imagen Asistido por Computador/instrumentación , Telemedicina/instrumentación , Sistemas de Computación , Estudios de Evaluación como Asunto , Humanos , Microcomputadores , Procesamiento de Señales Asistido por Computador
20.
Wei Sheng Wu Xue Bao ; 37(5): 368-73, 1997 Oct.
Artículo en Zh | MEDLINE | ID: mdl-11189362

RESUMEN

The beta-glucosidase from Rhizopus japonicus IFO5318 was purified by Ammonium sulfate salting out and column chromatographies with the recovery of 22%. The molecular weight of the enzyme was about 4.0 x 10(5), consisting of four identical subunits; The optimum reaction temperature and pH for the beta-glucosidase were 55 degrees C and pH 5.5, respectively; While the enzyme was sensitive to heat, it could be stable at a wide range of pH. The Km and Vmax values of the enzyme were 0.825 mg.ml-1 and 135.4 mumol.min-1.mg-1, respectively, using p-Nitrophenyl-beta-D-glucopyranoside as a substrate. The beta-glucosidase exhibited strongest hydrolysis effect on cellobiose and some of its activity could be inhibited by SDS, Fe3+ and Hg2+.


Asunto(s)
Rhizopus/química , beta-Glucosidasa/aislamiento & purificación , Peso Molecular , beta-Glucosidasa/química
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