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1.
Ann Oncol ; 30(12): 1950-1958, 2019 12 01.
Artículo en Inglés | MEDLINE | ID: mdl-31566666

RESUMEN

BACKGROUND: Gemcitabine plus cisplatin (GC) is the standard treatment of advanced biliary tract cancer (BTC); however, it causes nausea, vomiting, and anorexia, and requires hydration. Gemcitabine plus S-1 (GS) reportedly has equal to, or better, efficacy and an acceptable toxicity profile. We aimed to confirm the non-inferiority of GS to GC for patients with advanced/recurrent BTC in terms of overall survival (OS). PATIENTS AND METHODS: We undertook a phase III randomized trial in 33 institutions in Japan. Eligibility criteria included chemotherapy-naïve patients with recurrent or unresectable BTC, an Eastern Cooperative Oncology Group Performance Status of 0 - 1, and adequate organ function. The calculated sample size was 350 with a one-sided α of 5%, a power of 80%, and non-inferiority margin hazard ratio (HR) of 1.155. The primary end point was OS, while the secondary end points included progression-free survival (PFS), response rate (RR), adverse events (AEs), and clinically significant AEs defined as grade ≥2 fatigue, anorexia, nausea, vomiting, oral mucositis, or diarrhea. RESULTS: Between May 2013 and March 2016, 354 patients were enrolled. GS was found to be non-inferior to GC [median OS: 13.4 months with GC and 15.1 months with GS, HR, 0.945; 90% confidence interval (CI), 0.78-1.15; P = 0.046 for non-inferiority]. The median PFS was 5.8 months with GC and 6.8 months with GS (HR 0.86; 95% CI 0.70-1.07). The RR was 32.4% with GC and 29.8% with GS. Both treatments were generally well-tolerated. Clinically significant AEs were observed in 35.1% of patients in the GC arm and 29.9% in the GS arm. CONCLUSIONS: GS, which does not require hydration, should be considered a new, convenient standard of care option for patients with advanced/recurrent BTC. CLINICAL TRIAL NUMBER: This trial has been registered with the UMIN Clinical Trials Registry (http://www.umin.ac.jp/ctr/index.htm), number UMIN000010667.


Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/administración & dosificación , Neoplasias del Sistema Biliar/tratamiento farmacológico , Cisplatino/administración & dosificación , Desoxicitidina/análogos & derivados , Adulto , Anciano , Protocolos de Quimioterapia Combinada Antineoplásica/efectos adversos , Neoplasias del Sistema Biliar/epidemiología , Neoplasias del Sistema Biliar/patología , Cisplatino/efectos adversos , Desoxicitidina/administración & dosificación , Desoxicitidina/efectos adversos , Supervivencia sin Enfermedad , Combinación de Medicamentos , Femenino , Humanos , Japón/epidemiología , Masculino , Persona de Mediana Edad , Náusea/inducido químicamente , Náusea/patología , Ácido Oxónico/administración & dosificación , Ácido Oxónico/efectos adversos , Tegafur/administración & dosificación , Tegafur/efectos adversos , Vómitos/inducido químicamente , Vómitos/patología , Gemcitabina
2.
Transplant Proc ; 44(3): 806-9, 2012 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-22483501

RESUMEN

Magnetic compression anastomosis (MCA) provides a minimally invasive treatment creating a nonsurgical, sutureless enteric anastomosis in conjunction with an interventional radiologic technique by using 2 high-power magnets. Recently, the MCA technique has been applied to bile duct strictures after living donor liver transplantation or major hepatectomy. Herein we described use of MCA for bile duct stenosis 5 months after donor left hepatectomy in a 24-year-old man who presented with a stricture at the porta hepatis and intrahepatic bile duct dilatation. Unsuccessful transpapillary biliary drainage and balloon dilatation through a percutaneous transhepatic biliary drainage (PTBD) route led to the MCA. A 4-mm-diameter cylindrical samarium-cobalt (Sm-Co) daughter magnet with a long nylon wire was placed at the superior site of the obstruction through the PTBD route. A 5-mm-diameter Sm-Co parent magnet with an attached nylon handle was endoscopically inserted into the common bile duct and placed at the inferior site of obstruction. The 2 magnets were attracted, sandwiching the stricture and establishing a reanastomosis. In conclusion, the MCA technique was a unique procedure for choledochocholedochostomy in a patient with bile duct stenosis after donor hepatectomy.


Asunto(s)
Conductos Biliares Intrahepáticos/cirugía , Procedimientos Quirúrgicos del Sistema Biliar , Hepatectomía/efectos adversos , Donadores Vivos , Magnetismo , Adulto , Humanos , Trasplante de Hígado , Masculino
3.
Transplant Proc ; 41(1): 268-70, 2009.
Artículo en Inglés | MEDLINE | ID: mdl-19249532

RESUMEN

In September 2006, we initiated regular screening of biliary strictures (BS) by endoscopic retrograde cholangiography (ERC) within 6 months after removal of external stents among duct-to-duct biliary reconstructed adult living donor liver transplantations (LDLT). From March 2000 to January 2008, we retrospectively evaluated 45 primary adult LDLTs who had survived >1 month. We separated the cases into 2 groups-the early cases (March 2000 to August 2006: n = 34) and the late cases (September 2006 to January 2008: n = 11)-to compare the incidences of BS and the success rates of endoscopic treatments. Median follow-up of the late cases (8.0 months) was shorter than that of the early cases (38.5 months; P = .0003). The overall incidence of BS was 36% (16/45), with 32% (11/34) among the early and 45% (5/11) among the late cases (P = .18). BS was successfully treated by endoscopic management in 4/5 (80%) late cases and 3/11 (27%) early cases (P = .049). Two early patients required operative biliary reconstructions. Endoscopic procedure-related complications developed in 2 patients among the early cases. Early postoperative regular screening of BS by ERC for duct-to-duct biliary reconstructions may be effective to avoid surgical interventions after adult LDLT. However, repeat ERCs have a risk for pancreatitis and other complications. Further investigations and longer follow-up are needed to confirm the efficacy and safety of a regular examination by ERC for duct-to-duct biliary reconstructions in LDLT.


Asunto(s)
Colangiopancreatografia Retrógrada Endoscópica/métodos , Adulto , Conductos Biliares/cirugía , Procedimientos Quirúrgicos del Sistema Biliar , Incompatibilidad de Grupos Sanguíneos , Colestasis/diagnóstico , Colestasis/cirugía , Femenino , Humanos , Hígado/anatomía & histología , Trasplante de Hígado/efectos adversos , Donadores Vivos , Masculino , Persona de Mediana Edad , Tamaño de los Órganos , Stents
4.
Am J Physiol Heart Circ Physiol ; 292(5): H2040-50, 2007 May.
Artículo en Inglés | MEDLINE | ID: mdl-17293486

RESUMEN

It is important to regulate the oxygen concentration and scavenge oxygen radicals throughout the life of animals. In mammalian embryos, proper oxygen concentration gradually increases in utero and excessive oxygen is rather toxic during early embryonic development. Reactive oxygen species (ROS) are generated as by-products in the respiratory system and increased under inflammatory conditions. In the pathogenesis of a variety of adult human diseases such as cancer and cardiovascular disorders, ROS cause an enhancement of tissue injuries. ROS promote not only the development of atherosclerosis but also tissue injury during the reperfusion process. The thioredoxin (TRX) system is one of the most important mechanisms for regulating the redox balance. TRX is a small redox active protein distributed ubiquitously in various mammalian tissues and cells. TRX acts as not only an antioxidant but also an anti-inflammatory and an antiapoptotic protein. TRX is induced by oxidative stress and released from cells in response to oxidative stress. In various human diseases, the serum/plasma level of TRX is a well-recognized biomarker of oxidative stress. Here we discuss the roles of TRX on oxygen stress and redox regulation from different perspectives, in embryogenesis and in adult diseases focusing on cardiac disorders.


Asunto(s)
Cardiopatías/embriología , Cardiopatías/fisiopatología , Corazón/embriología , Corazón/fisiopatología , Oxígeno/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Tiorredoxinas/metabolismo , Animales , Humanos , Modelos Cardiovasculares , Estrés Oxidativo
6.
Endoscopy ; 34(9): 738-41, 2002 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-12195334

RESUMEN

Although previous retrospective reports have demonstrated the developmental course of several colorectal tumors, the natural history and progression of depressed carcinoma, especially in the early stage, remains obscure. We report a case of superficial depressed tumor in the transverse colon in a 71-year-old man, which did not change in size and gross configuration through prospective colonoscopic observation over a period of 19 months but which was finally diagnosed as early-stage submucosal invasive cancer. Most depressed cancers have been supposed to arise de novo and grow rapidly, showing aggressive behavior when 10 mm or less in size. However, this case report may suggest that even a depressed tumor may grow to approximately 10 mm within the mucosal layer over a few years and that the growth of colorectal tumors, whether they are polypoid or depressed in configuration, might be fairly slow.


Asunto(s)
Adenocarcinoma/diagnóstico , Neoplasias del Colon/diagnóstico , Colonoscopía , Adenocarcinoma/patología , Anciano , Neoplasias del Colon/patología , Humanos , Masculino , Invasividad Neoplásica
7.
Circ Res ; 89(6): 540-6, 2001 Sep 14.
Artículo en Inglés | MEDLINE | ID: mdl-11557742

RESUMEN

In the present study, the mechanisms and importance of the Fc portion of immunoglobulin in experimental giant cell myocarditis were examined. Giant cell myocarditis was induced in rats by immunization of porcine cardiac myosin. Human intact immunoglobulin (1 g. kg(-1). d(-1)) or F(ab')(2) fragments of human immunoglobulin (1 g. kg(-1). d(-1)) were administered intraperitoneally daily on days 1 to 21. Intact immunoglobulin administration significantly ameliorated myocarditis, but F(ab')(2) fragments did not. The ribonuclease protection assay revealed that therapy with intact immunoglobulin, but not F(ab')(2) fragments, suppressed the mRNA expressions of inflammatory and proinflammatory cytokines. Immunohistochemical analysis showed that therapy with intact immunoglobulin, but not F(ab')(2) fragments, suppressed dendritic cell (DC) expression during both the early and the subsequent fulminant phases. Moreover, the early treatment of intact immunoglobulin until the 11th day or 14th day, when the expression of DCs was completely suppressed, ameliorated myocarditis. However, the late treatment of intact immunoglobulin beginning on day 15, when the expression of DCs had already been completed, failed to ameliorate the condition. An in vitro study showed that intact immunoglobulin, but not F(ab')(2) fragments, suppressed the lipopolysaccharide-induced interleukin-1beta production associated with the downregulation of CD32 antigen (Fcgamma receptor II) expression. Thus, intact immunoglobulin therapy markedly suppressed myocarditis as a result of Fc receptor-mediated anti-inflammatory action, and the suppression of the disease was associated with the suppression of DCs, ie, the suppression of the initial antigen-priming process in experimental giant cell myocarditis.


Asunto(s)
Inmunoglobulinas/uso terapéutico , Miocarditis/tratamiento farmacológico , Receptores Fc/fisiología , Animales , Peso Corporal/efectos de los fármacos , Células Dendríticas/efectos de los fármacos , Regulación de la Expresión Génica/efectos de los fármacos , Humanos , Fragmentos Fab de Inmunoglobulinas/uso terapéutico , Inyecciones Intraperitoneales , Interleucina-1/metabolismo , Lipopolisacáridos/farmacología , Factores Inhibidores de la Migración de Macrófagos/genética , Miocarditis/inmunología , Miocarditis/patología , Miocardio/inmunología , Miocardio/metabolismo , Miocardio/patología , Miosinas/administración & dosificación , Miosinas/inmunología , Tamaño de los Órganos/efectos de los fármacos , ARN Mensajero/efectos de los fármacos , ARN Mensajero/genética , ARN Mensajero/metabolismo , Ratas , Ratas Endogámicas Lew , Células U937
8.
Jpn Circ J ; 65(6): 491-4, 2001 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-11407728

RESUMEN

An increase in oxidative stress is thought to be involved in the progression of heart disease, but the serum level of thioredoxin (TRX), which regulates the cellular redox state, has not been investigated in patients with heart diseases. The present study determined serum TRX levels with a sandwich enzyme-linked immunosorbent assay in a total of 39 patients with dilated cardiomyopathy (DCM) (n=5), acute coronary syndrome (ACS) (n=7) or stable angina (n=18), including effort angina (n=7) and vasospastic angina (n=11), and in control subjects (n=7). The serum TRX level in patients with New York Heart Association (NYHA) functional classes III and IV (n=8, 33.3+/-8.6 ng/ml) was significantly higher than in the control subjects (n=7, 14.0+/-4.6 ng/ml). In addition, the serum TRX levels correlated positively with the severity of NYHA class, and negatively with the left ventricular ejection fraction. The serum TRX levels were elevated in patients with ACS and DCM compared with the controls. These results indicate a possible association between TRX concentration and the severity of heart failure.


Asunto(s)
Insuficiencia Cardíaca/sangre , Tiorredoxinas/sangre , Adulto , Anciano , Cardiomiopatía Dilatada/sangre , Cardiomiopatía Dilatada/etiología , Estudios de Casos y Controles , Enfermedad Coronaria/sangre , Enfermedad Coronaria/etiología , Ensayo de Inmunoadsorción Enzimática , Femenino , Insuficiencia Cardíaca/etiología , Humanos , Masculino , Persona de Mediana Edad , Estrés Oxidativo/fisiología , Volumen Sistólico , Disfunción Ventricular Izquierda
9.
Jpn Circ J ; 65(6): 561-4, 2001 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-11407741

RESUMEN

Redox regulating mechanisms may be involved in the pathogenesis of viral myocarditis and thioredoxin (TRX) is a small multifunctional protein that contains a redox active sequence. The present study investigated the histopathology and characteristics of TRX expression in acute coxsackievirus B3 myocarditis in inbred strains of mice (severe myocarditis in DBA/2 mice, moderate myocarditis in BALB/c mice and mild myocarditis in C57BL/6 mice). Thioredoxin was upregulated and its expression correlated with the severity of the disease. In addition, 8-hydroxy-2'-deoxyguanosine, which is an established marker for oxidative stress, was concominantly positive in damaged myocytes. Thus, TRX may be specifically induced by the acute inflammatory stimuli in murine viral myocarditis, and the severity and development of acute viral myocarditis may be regulated by the cellular redox state.


Asunto(s)
Miocarditis/metabolismo , Tiorredoxinas/biosíntesis , Tiorredoxinas/metabolismo , Animales , Infecciones por Coxsackievirus/etiología , Infecciones por Coxsackievirus/metabolismo , Modelos Animales de Enfermedad , Inmunohistoquímica , Masculino , Ratones , Ratones Endogámicos , Miocarditis/etiología , Miocarditis/virología , Miocardio/química , Miocardio/patología , Oxidación-Reducción , Estrés Oxidativo , Tasa de Supervivencia , Regulación hacia Arriba
10.
J Org Chem ; 65(7): 2090-5, 2000 Apr 07.
Artículo en Inglés | MEDLINE | ID: mdl-10774030

RESUMEN

Selenobenzophenone reacts as a diene with dimethyl acetylenedicarboxylate (DMAD) to lead to dimethyl 1H-1-diphenylmethyl-1-phenyl-2-benzoselenopyran-3,4-dicarboxylate (5c) in moderate yield; the initial [4 + 2] cycloaddition is followed by the addition of another 1 mol equiv of selenobenzophenone. The reaction might proceed through carbene insertion of the primary cycloadduct. On the other hand, 4,4'-dimethoxyselenobenzophenone combines as a diene with DMAD furnishing dimethyl 1H-1-p-methoxyphenyl-6-methoxy-2-benzoselenopyran-3,4-dicarboxylate (4a). The reaction of benzoselenopyran derivative (4) with diaryldiazomethanes afforded another type of carbene insertion product.

11.
Jpn Circ J ; 64(4): 283-6, 2000 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-10783051

RESUMEN

Immunogenetic mechanisms may be involved in the pathogenesis of myocarditis and dilated cardiomyopathy. The present study investigated the incidence, histopathology and histocompatibility characteristics of experimental giant cell myocarditis in various strains of rats. Experimental giant cell myocarditis was induced by immunization with porcine cardiac myosin in Lewis (RT-1(l)), Dahl (DIR/Eis) (RT-1(l)), Fisher (RT-1(lv 1)) rats, but not in Dahl (DIS/Eis) (RT-1(l)) or Brown Norway (RT-1(n)). Myocarditis was most severe in the Lewis rats and their heart weight/body weight ratio was significantly higher than that of control rats immunized with Freund's complete adjuvant alone. In conclusion, this study provides evidence that the expression and severity of experimental giant cell myocarditis may be determined mainly by genetic factors, including both major histocompatibility complex genes as well as other genes, which may be controlled by an immune mechanism.


Asunto(s)
Miocarditis/genética , Animales , Células Gigantes/inmunología , Células Gigantes/patología , Miocarditis/inmunología , Miocarditis/patología , Ratas , Ratas Endogámicas , Especificidad de la Especie
12.
FEBS Lett ; 472(1): 109-13, 2000 Apr 21.
Artículo en Inglés | MEDLINE | ID: mdl-10781815

RESUMEN

To examine the possible involvement of a redox regulating mechanism in the pathogenesis of immune-mediated myocarditis, myocarditis was induced by immunization of porcine cardiac myosin in rats and immunohistochemistry and Western blot for thioredoxin (TRX) were performed. Immunohistochemistry for 8-hydroxy-2'-deoxyguanosine (8-OHdG) and nuclear factor kappa-B (NF-kappaB) was also performed. TRX was upregulated in the acute stage, but not in the chronic stage, and the expression was correlated with the severity of the disease. Damaged myocytes were strongly immunostained for 8-OHdG and NF-kappaB. Thus, TRX may be specifically induced by acute inflammatory stimuli, and the development of acute immune-mediated myocarditis may be regulated by the cellular redox state via TRX.


Asunto(s)
Células Gigantes/metabolismo , Miocarditis/metabolismo , Tiorredoxinas/metabolismo , 8-Hidroxi-2'-Desoxicoguanosina , Animales , Western Blotting , Desoxiguanosina/análogos & derivados , Desoxiguanosina/metabolismo , Células Gigantes/patología , Inmunohistoquímica , Miocarditis/inmunología , Miocarditis/patología , Miocardio/química , Miocardio/patología , Miosinas/química , Miosinas/inmunología , FN-kappa B/metabolismo , Oxidación-Reducción , Ratas , Ratas Endogámicas Lew , Porcinos , Tiorredoxinas/genética , Vacunación
13.
Jpn Circ J ; 64(12): 977-81, 2000 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-11194294

RESUMEN

To investigate the precise disease progression in myocarditis, Lewis rats were injected with porcine cardiac myosin, and C3H/He mice were inoculated with coxsackievirus B3. Both were killed serially, and the hearts were stained with hematoxylin-eosin to compare their pathological characteristics. In viral myocarditis, viral replication in the myocardium resulted in myocardial necrosis with inflammation, and the lesions were distributed transmurally, as previously reported. On the other hand, in giant cell myocarditis, inflammatory lesions appeared at first around the capillaries in the epicardium, and thereafter spread transmurally. Pericardial effusion was noticed in all the rats with myocarditis in the fulminant stage. Levels of interleukin (IL) -1beta and IL-6 in the pericardial effusion were elevated compared with the serum cytokines at the peak of inflammation. However, interferon-gamma in both the pericardial effusion and serum was not elevated. The cause of the myocardial lesions that developed in rats with giant cell myocarditis may be some active inflammatory process via the pericardial effusion.


Asunto(s)
Citocinas/metabolismo , Células Gigantes/patología , Miocarditis/patología , Derrame Pericárdico/complicaciones , Ratas/metabolismo , Animales , Enterovirus Humano B/crecimiento & desarrollo , Fibrosis/inducido químicamente , Fibrosis/etiología , Inflamación/complicaciones , Interleucina-1/metabolismo , Interleucina-6/metabolismo , Ratones , Ratones Endogámicos C3H , Miocarditis/inducido químicamente , Miocarditis/microbiología , Miosinas/farmacología , Necrosis , Derrame Pericárdico/química , Derrame Pericárdico/patología , Ratas/microbiología , Ratas Endogámicas Lew
14.
Jpn Circ J ; 61(8): 715-8, 1997 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-9276778

RESUMEN

A 65-year-old man was admitted with a diagnosis of arteriosclerosis obliterans. He had a 3-month history of intermittent claudication of the right leg. Physical examination revealed absence of pulsation of the right posterior tibial artery. Contrast angiography of lower extremities showed several obstructive lesions below the right popliteal artery. As interventional and surgical approached were not indicated, the patient was treated with exercise with heparin pretreatment (5,000 IU). As a result, walk distance on a floor was increased from 400 m to 2,000 m, and repeat magnetic resonance angiography revealed increased flow to the right lower extremity. Thus, he was successfully treated with exercise and heparin pretreatment without any side effects.


Asunto(s)
Anticoagulantes/uso terapéutico , Arteriosclerosis Obliterante/terapia , Terapia por Ejercicio , Heparina/uso terapéutico , Anciano , Arteriosclerosis Obliterante/complicaciones , Arteriosclerosis Obliterante/diagnóstico por imagen , Arteriosclerosis Obliterante/tratamiento farmacológico , Terapia Combinada , Humanos , Claudicación Intermitente/diagnóstico por imagen , Claudicación Intermitente/tratamiento farmacológico , Claudicación Intermitente/etiología , Claudicación Intermitente/terapia , Angiografía por Resonancia Magnética , Masculino , Radiografía , Arterias Tibiales/diagnóstico por imagen , Arterias Tibiales/patología
15.
J Biochem ; 83(5): 1449-58, 1978 May.
Artículo en Inglés | MEDLINE | ID: mdl-207685

RESUMEN

Ca2+/protein modulator-dependent and -independent guanosine 3':5'-monophosphate (cGMP) phosphodiesterases were separated from hog heart. The protein modulator-free Ca2+/protein modulator-dependent enzyme was partially purified by repeated DEAE-cellulose column chromatography and heat treatment. The final preparation of this enzyme showed no significant basal activity under the standard assay conditions. Lineweaver-Burk plots of the Ca2+/protein modulator-dependent enzyme activity indicated the presence of only a single kinetic form of the enzyme with Km=2.0 X 10(-6) M for for cGMP, whereas the plots for the independent enzyme were anomalous, showing both high and low K m values for cGMP. The Ca2+/protein modulator-dependent enzyme proved relatively stable at 48 degrees C for 1 h, but the independent form lost its activity under the same conditions. Furthermore, 50% inhibition of the dependent enzyme activity, but only 10% inhibition of the independent enzyme activity, was observed with 0.1 mM adenosine 3':5'-monophosphate (cAMP) when 1 muM cGMP was employed as a substrate.


Asunto(s)
3',5'-GMP Cíclico Fosfodiesterasas/aislamiento & purificación , Calcio/farmacología , Proteínas Musculares/farmacología , Miocardio/enzimología , Porcinos/metabolismo , 3',5'-GMP Cíclico Fosfodiesterasas/metabolismo , Animales , AMP Cíclico/farmacología , Estabilidad de Medicamentos , Humanos , Cinética , Proteínas Musculares/aislamiento & purificación , Miocardio/química
16.
Biochim Biophys Acta ; 522(1): 96-103, 1978 Jan 12.
Artículo en Inglés | MEDLINE | ID: mdl-23167

RESUMEN

The reversible heat activation and cold inactivation of tyrosine aminotransferase (L-tyrosine:2-oxoglutarate aminotransferase, EC 2.6.1.5) of chick liver were investigated. When the enzyme obtained by gel filtration was preincubated at 37 degrees C for 10 min with 50 micrometer pyridoxal 5'-phosphate (pyridoxal-5'-P), a 7-fold increase in enzyme activity was detected. When the preincubated enzyme was cooled to 0 degrees C, it lost its activity. Furthermore, the dramatic cyclical changes in enzyme activity occurred by sequential heating at 37 degrees C and cooling to 0 degrees C of the enzyme, in the presence of pyridoxal-5'-P, over shorter periods of time without loss of enzyme activity. However, when alpha-ketoglutarate was added to the enzyme during cold exposure, no further decrease in activity was observed. This protective effect was seen at a concentration of 5 muM.


Asunto(s)
Hígado/enzimología , Tirosina Transaminasa/metabolismo , Animales , Pollos , Activación Enzimática , Ácidos Cetoglutáricos/farmacología , Cinética , Masculino , Temperatura , Tirosina Transaminasa/aislamiento & purificación
18.
Physiol Chem Phys ; 7(2): 125-32, 1975.
Artículo en Inglés | MEDLINE | ID: mdl-239431

RESUMEN

Inhibition of cAMP phosphodiesterase from rat liver by nicotinamide and its homologues was studied. Among the several compounds tested, such agents as nicotinamide, N2-ethylnicotinamide, N2-methylnicotinamide, N,N-diethylnicotinamide, 3-acetylpyridine, methylnicotinate, and ethylnicotinate showed potent inhibition of cAMP phosphodiesterase, with an over 90% inhibition by 5 mM ethylnicotinate when cAMP was used as substrate at a 0.48 x 10(-7) M concentration. A comparison of the inhibitory curves of theophylline, papaverine, and ethylnicotinate on enzyme activity showed them to be approximately coincident. Furthermore, the plots with abscissa of equal increments per concentration of ethylnicotinate in the presence of theophylline or papaverine coincided with that in the absence of these agents.


Asunto(s)
3',5'-AMP Cíclico Fosfodiesterasas/antagonistas & inhibidores , Niacinamida/farmacología , Inhibidores de Fosfodiesterasa , Animales , AMP Cíclico/metabolismo , Ésteres , Concentración de Iones de Hidrógeno , Hígado/enzimología , Masculino , Niacinamida/análogos & derivados , Ácidos Nicotínicos/farmacología , Papaverina/farmacología , Ratas , Teofilina/farmacología , Tritio
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