Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 13 de 13
Filtrar
1.
Sensors (Basel) ; 21(24)2021 Dec 07.
Artículo en Inglés | MEDLINE | ID: mdl-34960271

RESUMEN

Degradation of fast response pressure-sensitive paints (PSP) above room temperature is a serious problem for PSP measurements in high-temperature environments. A standard polymer-ceramic PSP (PC-PSP) composed of platinum(II)-5,10,15,20-tetrakis-(2,3,4,5,6-pentafluorphenyl)-porphyrin (PtTFPP), titania particles and poly(isobutyl methacrylate) (polyIBM) was characterized to elucidate the degradation mechanism. Applying a two-gate lifetime-based method, the PC-PSP has sufficient pressure and temperature sensitivities even at 100 °C, while the luminescence intensity significantly decreases during the test. Subsequent measurements on thermal and photostability as well as luminescence spectra reveal that the main cause of the degradation is the photodegradation of PtTFPP due to direct exposure of the dye molecules to the atmosphere. In order to suppress such degradation, a small amount of urethane resin is added to the dye solution as a simple additional step in the preparation of PC-PSP. The addition of the urethane resin significantly reduces the degradation of the PSP, although its time response is slightly slower than that of the standard PC-PSP.

2.
Intern Med ; 58(15): 2151-2157, 2019 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-30996185

RESUMEN

Objective The association between narcolepsy and rapid eye movement (REM)-related obstructive sleep apnea (OSA) has not been reported. This study aimed to examine the prevalence of REM-related OSA in narcolepsy patients. Methods From January 2013 to April 2018, 141 adult patients were diagnosed with narcolepsy using nocturnal polysomnography and the multiple sleep latency test. The prevalence of REM-related OSA in narcolepsy patients was retrospectively reviewed. Three criteria were used to determine REM-related OSA: Definition #1, an overall apnea-hypopnea index (AHI) ≥5 and AHI during REM (AHIREM)/AHI during non-rapid eye movement (NREM) (AHINREM) ≥2; Definition #2, an overall AHI ≥5 and AHIREM/AHINREM≥2 and AHINREM <15; and Definition #3, an overall AHI ≥5 and AHIREM/AHINREM≥2 and AHINREM <8 plus an REM sleep duration >10.5 minutes. Results Of the 141 narcolepsy patients, 26 were diagnosed with narcolepsy with cataplexy (NA-CA) and 115 with narcolepsy without cataplexy (NA w/o CA). Seventeen patients with NA-CA and 39 with NA w/o CA had OSA. According to Definition #1, the prevalence of REM-related OSA was 47.1% and 41.0%, respectively, in OSA patients with NA-CA and NA w/o CA; according to Definition #2, the respective prevalence was 47.1% and 38.5%, while that according to Definition #3 was 41.2% and 25.6%. No significant differences were found in the prevalence of REM-related OSA for each definition. Conclusion A high prevalence of REM-related OSA was confirmed in adult narcolepsy patients with OSA. Compared to previous reports, we noted a high frequency of REM-related OSA satisfying the relatively strict Definition #3. These results might reflect the pathophysiological characteristics of narcolepsy.


Asunto(s)
Narcolepsia/fisiopatología , Apnea Obstructiva del Sueño/fisiopatología , Sueño REM/fisiología , Adulto , Femenino , Humanos , Japón/epidemiología , Masculino , Persona de Mediana Edad , Prevalencia , Estudios Retrospectivos , Apnea Obstructiva del Sueño/epidemiología
3.
Intern Med ; 58(4): 477-485, 2019 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-30333396

RESUMEN

Objective Regional disparities were observed in the outcomes of interferon (IFN)-based therapy for chronic hepatitis C virus (HCV) infection in a Japanese nationwide study. However, whether or not these regional disparities are observed in the outcomes of direct-acting antiviral drugs, including sofosbuvir (SOF) plus ribavirin (RBV) therapy, remains unclear. Methods We conducted a multicenter study to assess the efficacy of SOF plus RBV therapy for HCV genotype 2 infection in Tochigi Prefecture and its vicinity, in which IFN-based therapy yielded a low sustained virologic response (SVR) rate. In addition, we divided Tochigi Prefecture into six regions to examine regional disparities in the SVR. Patients We enrolled patients with chronic HCV genotype 2 infection. Results Of the 583 patients enrolled, 569 (97.6%) completed the treatment, and 566 (97.1%) also complied with post-treatment follow-up for 12 weeks. The overall SVR12 rate was 96.1% by per protocol and 93.7% by intention-to-treat analyses. No marked differences were observed in the SVR12 between subjects ≥65 and <65 years of age. Although large gaps were observed in the characteristics of patients and accessibility to medical resources, there was no significant difference in the SVR12 rate among the six regions in Tochigi Prefecture. Conclusion SOF plus RBV therapy was effective for HCV genotype 2 infection in an area where IFN-based therapy had previously shown unsatisfactory results. In addition, no regional disparities in the SVR12 were observed in Tochigi Prefecture.


Asunto(s)
Antivirales/uso terapéutico , Quimioterapia Combinada , Hepacivirus/genética , Hepatitis C Crónica/tratamiento farmacológico , Interferones/uso terapéutico , Ribavirina/uso terapéutico , Sofosbuvir/uso terapéutico , Anciano , Femenino , Genotipo , Geografía , Hepatitis C Crónica/epidemiología , Humanos , Japón/epidemiología , Masculino , Persona de Mediana Edad , Respuesta Virológica Sostenida
4.
J Clin Pharmacol ; 54(1): 109-19, 2014 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-24115082

RESUMEN

A multicenter, open-label, dose-escalation phase 1/2 study was undertaken to evaluate the optimal subcutaneous tocilizumab dose that would result in exposure comparable to the intravenous tocilizumab 8-mg/kg approved dose in patients with rheumatoid arthritis. A pharmacokinetic and biomarker approach was used to estimate the clinical optimal dose regimen of subcutaneous tocilizumab. Safety and efficacy of subcutaneous tocilizumab were assessed as secondary end points. Patients received subcutaneous tocilizumab at 81 mg every 2 weeks (q2w) (n = 8), 162 mg q2w (n = 12), or 162 mg weekly (qw) (n = 12) for 24 weeks. 88% of 162-mg q2w patients and 100% of 162-mg qw patients maintained mean serum trough tocilizumab concentrations of ≥1 µg/mL, and had exposure comparable with the approved intravenous tocilizumab dose of 8 mg/kg; this resulted in normalized C-reactive protein levels and improvement in ACR20/50/70 responses. The most common adverse events were abnormal laboratory results, which were mild in severity. Anti-tocilizumab antibodies were detected in a few patients in the 81-mg q2w and 162-mg qw groups. In conclusion, coupled with efficacy and tolerability results, the appropriate dose of subcutaneous tocilizumab was determined to be 162 mg q2w for Japanese patients.


Asunto(s)
Anticuerpos Monoclonales Humanizados/uso terapéutico , Antirreumáticos/uso terapéutico , Artritis Reumatoide/tratamiento farmacológico , Biomarcadores/análisis , Adulto , Anciano , Anticuerpos Monoclonales Humanizados/administración & dosificación , Anticuerpos Monoclonales Humanizados/efectos adversos , Proteína C-Reactiva/análisis , Proteína C-Reactiva/metabolismo , Determinación de Punto Final , Ensayo de Inmunoadsorción Enzimática , Femenino , Humanos , Inmunoglobulina E/análisis , Inmunoglobulina E/inmunología , Fragmentos Fab de Inmunoglobulinas/análisis , Fragmentos Fab de Inmunoglobulinas/inmunología , Inyecciones/efectos adversos , Japón , Masculino , Persona de Mediana Edad , Dolor/inducido químicamente , Dimensión del Dolor/efectos de los fármacos , Adulto Joven
5.
Clin Lung Cancer ; 14(4): 407-17, 2013 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-23490546

RESUMEN

BACKGROUND: Interstitial lung disease (ILD) is a serious adverse drug reaction associated with epidermal growth factor receptor tyrosine-kinase inhibitors (EGFR TKIs). Its risk factors are yet to be fully elucidated. We sought to identify proteomic biomarkers associated with ILD development in erlotinib-treated Japanese patients with non-small-cell lung cancer (NSCLC) to build predictive models. PATIENTS AND METHODS: We conducted a nested case-control study. The participants were patients with NSCLC enrolled in a phase IV study of erlotinib in whom ILD developed within 120 days after erlotinib administration. The controls were randomly selected patients without ILD from the overall study cohort who were also treated with erlotinib. Serum samples were obtained before the first administration of erlotinib and were assayed by liquid chromatography-mass spectroscopy/mass spectroscopy (LC-MS/MS). Logistic regression analysis was performed to identify the peptide and proteins associated with ILD. RESULTS: A total of 645 patients were enrolled in the cohort; 15 case patients and 64 controls were analyzed. When multiplicity was taken into account, we were unable to statistically verify any genuine association between individual markers and ILD. Investigation of the predictive power based on leave-one-out cross-validation (LOOCV) showed that the area under the receiver operating characteristic curve was 0.73 at a maximum. Additional analysis suggested that 3 proteins (C3, C4A/C4B, and APOA1) have a stronger association with ILD than do the other proteins tested. CONCLUSION: We were unable to demonstrate predictive serum protein markers for ILD development. However, C3, C4A/C4B, and APOA1 are worthy of further investigation.


Asunto(s)
Biomarcadores de Tumor/sangre , Carcinoma de Pulmón de Células no Pequeñas/complicaciones , Enfermedades Pulmonares Intersticiales/diagnóstico , Neoplasias Pulmonares/complicaciones , Proteómica , Quinazolinas/efectos adversos , Adenocarcinoma/complicaciones , Adenocarcinoma/tratamiento farmacológico , Adenocarcinoma/metabolismo , Anciano , Carcinoma de Pulmón de Células no Pequeñas/tratamiento farmacológico , Carcinoma de Pulmón de Células no Pequeñas/metabolismo , Carcinoma de Células Escamosas/complicaciones , Carcinoma de Células Escamosas/tratamiento farmacológico , Carcinoma de Células Escamosas/metabolismo , Estudios de Casos y Controles , Receptores ErbB/antagonistas & inhibidores , Clorhidrato de Erlotinib , Femenino , Estudios de Seguimiento , Humanos , Enfermedades Pulmonares Intersticiales/sangre , Enfermedades Pulmonares Intersticiales/inducido químicamente , Neoplasias Pulmonares/tratamiento farmacológico , Neoplasias Pulmonares/metabolismo , Masculino , Estadificación de Neoplasias , Pronóstico , Inhibidores de Proteínas Quinasas/efectos adversos , Espectrometría de Masas en Tándem
6.
Purinergic Signal ; 7(4): 427-34, 2011 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-21656186

RESUMEN

Liver ischemia reperfusion injury is associated with both local damage to the hepatic vasculature and systemic inflammatory responses. CD39 is the dominant vascular endothelial cell ectonucleotidase and rapidly hydrolyses both adenosine triphosphate (ATP) and adenosine diphosphate to adenosine monophosphate. These biochemical properties, in tandem with 5'-nucleotidases, generate adenosine and potentially illicit inflammatory vascular responses and thrombosis. We have evaluated the role of CD39 in total hepatic ischemia reperfusion injury (IRI). Wildtype mice, Cd39-hemizygous mice (+/-) and matched Cd39-null mice (-/-); (n = 25 per group) underwent 45 min of total warm ischemia with full inflow occlusion necessitating partial hepatectomy. Soluble nucleoside triphosphate diphosphohydrolase (NTPDases) or adenosine/amrinone were administered to wildtype (n = 6) and Cd39-null mice (n = 6) in order to study protective effects in vivo. Parameters of liver injury, systemic inflammation, hepatic ATP determinations by P(31)-NMR and parameters of lung injury were obtained. All wildtype mice survived up to 7 days with minimal biochemical disturbances and minor evidence for injury. In contrast, 64% of Cd39+/- and 84% of Cd39-null mice required euthanasia or died within 4 h post-reperfusion with liver damage and systemic inflammation associated with hypercytokinemia. Hepatic ATP depletion was pronounced in Cd39-null mice posthepatic IRI. Soluble NTPDase or adenosine administration protected Cd39-deficient mice from acute reperfusion injury. We conclude that CD39 is protective in hepatic IRI preventing local injury and systemic inflammation in an adenosine dependent manner. Our data indicate that vascular CD39 expression has an essential protective role in hepatic IRI.

7.
Gastroenterology ; 135(5): 1751-60, 2008 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-18804472

RESUMEN

BACKGROUND & AIMS: Little is known about how endothelial cells respond to injury, regulate hepatocyte turnover and reconstitute the hepatic vasculature. We aimed to determine the effects of the vascular ectonucleotidase CD39 on sinusoidal endothelial cell responses following partial hepatectomy and to dissect purinergic and growth factor interactions in this model. METHODS: Parameters of liver injury and regeneration, as well as the kinetics of hepatocellular and sinusoidal endothelial cell proliferation, were assessed following partial hepatectomy in mice that do not express CD39, that do not express ATP/UTP receptor P2Y2, and in controls. The effects of extracellular ATP on vascular endothelial growth factor (VEGF), hepatocyte growth factor (HGF), and interleukin-6 responses were determined in vivo and in vitro. Phosphorylation of the endothelial VEGF receptor in response to extracellular nucleotides and growth factors was assessed in vitro. RESULTS: After partial hepatectomy, expression of the vascular ectonucleotidase CD39 increased on sinusoidal endothelial cells. Targeted disruption of CD39 impaired hepatocellular regeneration, reduced angiogenesis, and increased hepatic injury, resulting in pronounced vascular endothelial apoptosis, and decreased survival. Decreased HGF release by sinusoidal endothelial cells, despite high levels of VEGF, reduced paracrine stimulation of hepatocytes. Failure of VEGF receptor-2/KDR transactivation by extracellular nucleotides on CD39-null endothelial cells was associated with P2Y2 receptor desensitization. CONCLUSIONS: Regulated phosphohydrolysis of extracellular nucleotides by CD39 coordinates both hepatocyte and endothelial cell proliferation following partial hepatectomy. Lack of CD39 activity is associated with decreased hepatic regeneration and failure of vascular reconstitution.


Asunto(s)
Antígenos CD/biosíntesis , Apirasa/biosíntesis , Endotelio Vascular/metabolismo , Regeneración Hepática/fisiología , Hígado/patología , Animales , Apoptosis , Catálisis , Proliferación Celular , Células Cultivadas , Modelos Animales de Enfermedad , Endotelio Vascular/patología , Ensayo de Inmunoadsorción Enzimática , Hepatectomía , Factor de Crecimiento de Hepatocito/metabolismo , Hepatocitos/metabolismo , Hepatocitos/patología , Inmunohistoquímica , Inmunoprecipitación , Interleucina-6/metabolismo , Hígado/lesiones , Hígado/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , Factor A de Crecimiento Endotelial Vascular/metabolismo
8.
Diabetes ; 57(9): 2311-20, 2008 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-18567823

RESUMEN

OBJECTIVE: Extracellular nucleotides are important mediators of inflammatory responses and could also impact metabolic homeostasis. Type 2 purinergic (P2) receptors bind extracellular nucleotides and are expressed by major peripheral tissues responsible for glucose homeostasis. CD39/ENTPD1 is the dominant vascular and immune cell ectoenzyme that hydrolyzes extracellular nucleotides to regulate purinergic signaling. RESEARCH DESIGN AND METHODS: We have studied Cd39/Entpd1-null mice to determine whether any associated changes in extracellular nucleotide concentrations influence glucose homeostasis. RESULTS: Cd39/Entpd1-null mice have impaired glucose tolerance and decreased insulin sensitivity with significantly higher plasma insulin levels. Hyperinsulinemic-euglycemic clamp studies indicate altered hepatic glucose metabolism. These effects are mimicked in vivo by injection into wild-type mice of either exogenous ATP or an ecto-ATPase inhibitor, ARL-67156, and by exposure of hepatocytes to extracellular nucleotides in vitro. Increased serum interleukin-1beta, interleukin-6, interferon-gamma, and tumor necrosis factor-alpha levels are observed in Cd39/Entpd1-null mice in keeping with a proinflammatory phenotype. Impaired insulin sensitivity is accompanied by increased activation of hepatic c-Jun NH(2)-terminal kinase/stress-activated protein kinase in Cd39/Entpd1 mice after injection of ATP in vivo. This results in decreased tyrosine phosphorylation of insulin receptor substrate-2 with impeded insulin signaling. CONCLUSIONS: CD39/Entpd1 is a modulator of extracellular nucleotide signaling and also influences metabolism. Deletion of Cd39/Entpd1 both directly and indirectly impacts insulin regulation and hepatic glucose metabolism. Extracellular nucleotides serve as "metabolokines," indicating further links between inflammation and associated metabolic derangements.


Asunto(s)
Antígenos CD/genética , Antígenos CD/inmunología , Apirasa/genética , Apirasa/inmunología , Resistencia a la Insulina/inmunología , Hígado/metabolismo , Adenosina Trifosfato/metabolismo , Adenosina Trifosfato/farmacología , Tejido Adiposo Pardo/inmunología , Tejido Adiposo Pardo/metabolismo , Animales , Glucemia/metabolismo , Células Cultivadas , Citocinas/sangre , Metabolismo Energético/fisiología , Técnica de Clampeo de la Glucosa , Hepatocitos/citología , Hepatocitos/inmunología , Hepatocitos/metabolismo , Hiperinsulinismo/inmunología , Hiperinsulinismo/fisiopatología , Insulina/sangre , Proteínas Sustrato del Receptor de Insulina , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Proteínas Quinasas JNK Activadas por Mitógenos/metabolismo , Hígado/citología , Hígado/inmunología , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Músculo Esquelético/inmunología , Músculo Esquelético/metabolismo , Consumo de Oxígeno/fisiología , Páncreas/inmunología , Páncreas/metabolismo , Fosfoproteínas/metabolismo , Fosforilación , Transducción de Señal/fisiología
9.
Thromb Haemost ; 91(3): 576-86, 2004 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-14983235

RESUMEN

CD39 (ecto-nucleoside triphosphate diphosphohydrolase-1; E-NTPDase-1), is highly expressed on quiescent vascular endothelial cells and efficiently hydrolyzes extracellular ATP and ADP to AMP and ultimately adenosine. This action blocks extracellular nucleotide-dependent platelet aggregation and abrogates endothelial cell activation. However, CD39 enzymatic activity is rapidly lost following exposure to oxidant stress. Modulation of extracellular nucleotide levels may therefore play an important role in the pathogenesis of vascular injury. Acute ischemic injury of the bowel is a serious medical condition characterized by high mortality rates with limited therapeutic options. Here we evaluate the effects of cd39-deletion in mutant mice and the use of supplemental NTPDase or adenosine in influencing the outcomes of intestinal ischemia-reperfusion. Wild-type, cd39-null, or hemizygous cd39-deficient mice were subjected to intestinal ischemia. In selected animals, 0.2 U/g apyrase (soluble NTPDase) was administered prior to re-establishment of blood-flow. In parallel experiments adenosine/amrinone was infused over 60 min during reperfusion periods. Survival rates were determined, serum and tissue samples were taken. Intravital videomicroscopy and studies of vascular permeability were used to study platelet-endothelial cell interactions and determine capillary leakage. In wild-type animals, ischemia reperfusion injury resulted in 60% mortality within 48 hours. In mutant mice null or deficient for cd39, ischemia reperfusion-related death occurred in 80% of animals. Apyrase supplementation protected all wild-type animals from death due to intestinal ischemia but did not fully protect cd39-null and cd39-hemizygote mice. Adenosine/amrinone treatment failed to improve survival figures. In wild type mice, platelet adherence to postcapillary venules was significantly decreased and vascular integrity was well preserved following apyrase administration. In cd39-null mice, ischemia-reperfusion induced marked albumin leakage indicative of heightened vascular permaeability when compared to wild-type animals (p=0.04). Treatment with NTPDase or adenosine supplementation abrogated the increased vascular permeability in ischemic jejunal specimens of both wild-type mice and cd39-null. CD39 activity modulates platelet activation and vascular leak during intestinal ischemia reperfusion injury in vivo. The potential of NTPDases to maintain vascular integrity suggests potential pharmacological benefit of these agents in mesenteric ischemic injury.


Asunto(s)
Adenosina Trifosfatasas/biosíntesis , Antígenos CD/biosíntesis , Daño por Reperfusión/metabolismo , Adenosina/metabolismo , Adenosina Difosfato/metabolismo , Adenosina Trifosfatasas/genética , Adenosina Trifosfato/metabolismo , Animales , Antígenos CD/genética , Apirasa , Plaquetas/metabolismo , Capilares/metabolismo , AMP Cíclico/metabolismo , Citocinas/sangre , Endotelio Vascular/citología , Eliminación de Gen , Intestino Delgado/patología , Isquemia , Masculino , Ratones , Ratones Endogámicos C57BL , Microscopía por Video , Estrés Oxidativo , Permeabilidad , Peroxidasa/metabolismo , Activación Plaquetaria , Factores de Tiempo , Factor A de Crecimiento Endotelial Vascular/sangre
10.
Surg Today ; 33(11): 864-6, 2003.
Artículo en Inglés | MEDLINE | ID: mdl-14605960

RESUMEN

A case of distant metastasis to mesh-plug prosthesis in gastrointestinal cancer is presented herein. An 88-year-old man had received mesh-plug repair with high ligation for a recurrence of a right inguinal hernia. Six months later, advanced gastric cancer and advanced transverse colon cancer were detected, and therefore a distal gastrectomy and partial colectomy were performed. Two weeks after the operation, the patient complained of right groin tenderness, and the mesh-plug prosthesis was removed to control any infection. A histopathological investigation demonstrated adenocarcinoma in the plug prosthesis. The patient died of carcinomatosis peritonei 45 days after the last operation.


Asunto(s)
Adenocarcinoma/secundario , Neoplasias Gastrointestinales/patología , Hernia Inguinal/cirugía , Neoplasias Peritoneales/secundario , Mallas Quirúrgicas , Adenocarcinoma/patología , Adenocarcinoma/cirugía , Anciano , Anciano de 80 o más Años , Biopsia con Aguja , Resultado Fatal , Gastrectomía , Neoplasias Gastrointestinales/cirugía , Hernia Inguinal/patología , Humanos , Inmunohistoquímica , Masculino , Siembra Neoplásica , Neoplasias Peritoneales/patología , Neoplasias Peritoneales/cirugía , Reoperación
11.
J Surg Oncol ; 83(2): 94-8, 2003 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-12772202

RESUMEN

BACKGROUND AND OBJECTIVES: Superficial spreading type early gastric cancer is characterized by its atypical growth pattern and occasionally indistinct tumor margin. Because it is a rare form of early gastric cancer, the clinicopathological details are not apparent. The aim of this study was to clarify the clinicopathological features of the superficial spreading type of early gastric cancer. METHODS: A retrospective study was conducted in 1,062 surgically resected patients with early gastric cancer. Hospital records were compared between patients with superficial spreading type early gastric cancer and those with more common types of early gastric cancer. RESULTS: Sixty-nine patients (6.9%) had superficial spreading lesions. The male to female ratio was 1.2:1. The most frequent histological type was signet-ring cell carcinoma (32%). The distinguishing histopathological features were submucosal invasion (67%), lymphatic invasion (32%), and lymph node metastasis (30%). There were discrepancies in tumor area between surgical findings and pathological diagnosis in 24 patients (35%) with superficial spreading type. More extensive lymph node dissection was performed and all patients survived in the group with superficial spreading lesions. CONCLUSIONS: The most appropriate treatment for the superficial spreading type of early gastric cancer is wide surgical resection with extensive lymph node dissection.


Asunto(s)
Escisión del Ganglio Linfático , Ganglios Linfáticos/patología , Neoplasias Gástricas/patología , Neoplasias Gástricas/cirugía , Femenino , Gastrectomía , Humanos , Metástasis Linfática/patología , Masculino , Invasividad Neoplásica , Estudios Retrospectivos , Análisis de Supervivencia
13.
Blood ; 99(8): 2801-9, 2002 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-11929769

RESUMEN

Nucleoside triphosphate diphosphohydrolases (NTPDases) are a recently described family of ectonucleotidases that differentially hydrolyze the gamma and beta phosphate residues of extracellular nucleotides. Expression of this enzymatic activity has the potential to influence nucleotide P2 receptor signaling within the vasculature. We and others have documented that NTPDase1 (CD39, 78 kd) hydrolyzes both triphosphonucleosides and diphosphonucleosides and thereby terminates platelet aggregation responses to adenosine diphosphate (ADP). In contrast, we now show that NTPDase2 (CD39L1, 75 kd), a preferential nucleoside triphosphatase, activates platelet aggregation by converting adenosine triphosphate (ATP) to ADP, the specific agonist of P2Y(1) and P2Y(12) receptors. We developed specific antibodies to murine NTPDase1 and NTPDase2 and observed that both enzymes are present in the cardiac vasculature; NTPDase1 is expressed by endothelium, endocardium, and to a lesser extent by vascular smooth muscle, while NTPDase2 is associated with the adventitia of muscularized vessels, microvascular pericytes, and other cell populations in the subendocardial space. Moreover, NTPDase2 represents a novel marker for microvascular pericytes. Differential expression of NTPDases in the vasculature suggests spatial regulation of nucleotide-mediated signaling. In this context, NTPDase1 should abrogate platelet aggregation and recruitment in intact vessels by the conversion of ADP to adenosine monophosphate, while NTPDase2 expression would promote platelet microthrombus formation at sites of extravasation following vessel injury. Our data suggest that specific NTPDases, in tandem with ecto-5'-nucleotidase, not only terminate P2 receptor activation and trigger adenosine receptors but may also allow preferential activation of specific subsets of P2 receptors sensitive to ADP (e.g., P2Y(1), P2Y(3), P2Y(12)) and uridine diphosphate (P2Y(6)).


Asunto(s)
Apirasa/fisiología , Endotelio Vascular/enzimología , Activación Plaquetaria/efectos de los fármacos , Adenosina Trifosfatasas/genética , Adenosina Trifosfatasas/metabolismo , Adenosina Trifosfatasas/fisiología , Animales , Antígenos CD , Apirasa/genética , Apirasa/metabolismo , Células COS , Catálisis , Vasos Coronarios/enzimología , Humanos , Inmunohistoquímica , Ratones , Miocardio/enzimología , Activación Plaquetaria/fisiología , Transfección
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...