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1.
Ann Oncol ; 27(11): 2117-2123, 2016 11.
Artículo en Inglés | MEDLINE | ID: mdl-27502728

RESUMEN

BACKGROUND: T-cell infiltration in tumors has been used as a prognostic tool in non-small-cell lung cancer (NSCLC). However, the influence of smoking habit and histological type on tumor-infiltrating lymphocytes (TILs) in NSCLC remains unclear. PATIENTS AND METHODS: We evaluated the prognostic significance of TILs (CD4+, CD8+, CD20+, and FOXP3+) according to histological type and smoking habit using automatic immunohistochemical staining and cell counting in 218 patients with NSCLC. RESULTS: In multivariate survival analyses of clinical, pathological, and immunological factors, a high ratio of FOXP3+ to CD4+ T cells (FOXP3/CD4) [hazard ratio (HR): 4.46, P < 0.01 for overall survival (OS); HR: 1.96, P < 0.05 for recurrence-free survival (RFS)] and a low accumulation of CD20+ B cells (HR: 2.45, P = 0.09 for OS; HR: 2.86, P < 0.01 for RFS) were identified as worse prognostic factors in patients with adenocarcinoma (AD). In non-AD, a low number of CD8+ T cells were correlated with an unfavorable outcome (HR: 7.69, P < 0.01 for OS; HR: 3.57, P < 0.02 for RFS). Regarding smoking habit in AD, a high FOXP3/CD4 ratio was poorly prognostic with a smoking history (HR: 5.21, P < 0.01 for OS; HR: 2.38, P < 0.03 for RFS), whereas a low accumulation of CD20+ B cells (HR: 4.54, P = 0.03 for OS; HR: 2.94, P < 0.01 for RFS) was confirmed as an unfavorable factor in non-smokers with AD. CONCLUSIONS: A low number of CD8+ T cells in non-AD, a high FOXP3/CD4 ratio in smokers with AD, and a low number of CD20+ B cells in non-smokers with AD were identified as independent unfavorable prognostic factors in resected NSCLC. Evaluating the influence of histological type and smoking habit on the immunological environment may lead to the establishment of immunological diagnosis and appropriate individualized immunotherapy for NSCLC.


Asunto(s)
Carcinoma de Pulmón de Células no Pequeñas/patología , Linfocitos Infiltrantes de Tumor/patología , Pronóstico , Adulto , Anciano , Anciano de 80 o más Años , Antígenos CD20/inmunología , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD8-positivos/inmunología , Carcinoma de Pulmón de Células no Pequeñas/clasificación , Carcinoma de Pulmón de Células no Pequeñas/inmunología , Supervivencia sin Enfermedad , Femenino , Factores de Transcripción Forkhead/inmunología , Humanos , Estimación de Kaplan-Meier , Linfocitos Infiltrantes de Tumor/inmunología , Masculino , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Fumar/efectos adversos
3.
J Fish Biol ; 87(4): 958-66, 2015 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-26370909

RESUMEN

The influence of hatching date on the sex ratio of wild Gnathopogon caerulescens was examined. Cohorts reared from eggs collected in the early and middle parts of the spawning season showed almost balanced sex ratios, with female bias in some cohorts. Cohorts born later in the season mostly displayed male bias, and the mean proportion of males later in the season was significantly higher than in early- and mid-season cohorts. These results indicate that the sex ratio of G. caerulescens changes with the time of breeding, increasing along with the ambient water temperature of the lake.


Asunto(s)
Cyprinidae/fisiología , Procesos de Determinación del Sexo , Conducta Sexual Animal , Animales , Cruzamiento , Cyprinidae/embriología , Femenino , Masculino , Estaciones del Año , Agua de Mar/química , Razón de Masculinidad , Temperatura
6.
Nat Med ; 7(8): 954-60, 2001 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-11479629

RESUMEN

A novel anti-human DR5 monoclonal antibody, TRA-8, induces apoptosis of most tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-sensitive tumor cells both in vitro and in vivo. In contrast to both the membrane-bound form of human TRAIL, which induced severe hepatitis in mice, and the soluble form of human TRAIL, which induced apoptosis of normal human hepatocytes in vitro, TRA-8 did not induce significant cell death of normal human hepatocytes. However, both primary hepatocellular carcinoma cells and an established liver cancer cell line were highly susceptible to the killing mediated by TRA-8. We show here that elevated levels of cell-surface expression of DR5 and increased susceptibility to DR5-mediated apoptosis are characteristics of malignant tumor cells. In contrast, DR5 alone is not sufficient to trigger apoptosis of normal hepatocytes. Therefore, selective, specific targeting of DR5 with an agonistic antibody might be a safe and effective strategy for cancer therapy.


Asunto(s)
Anticuerpos Monoclonales/inmunología , Neoplasias Encefálicas/patología , Glioma/patología , Hepatocitos/citología , Receptores del Factor de Necrosis Tumoral/inmunología , Animales , Apoptosis/inmunología , Proteínas Reguladoras de la Apoptosis , Secuencia de Bases , Cartilla de ADN , Femenino , Humanos , Glicoproteínas de Membrana/fisiología , Ratones , Ratones Endogámicos BALB C , Receptores del Ligando Inductor de Apoptosis Relacionado con TNF , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Ligando Inductor de Apoptosis Relacionado con TNF , Células Tumorales Cultivadas , Factor de Necrosis Tumoral alfa/fisiología
7.
J Cell Biol ; 143(5): 1227-38, 1998 Nov 30.
Artículo en Inglés | MEDLINE | ID: mdl-9832551

RESUMEN

We isolated two novel actin filament (F-actin)-binding proteins from rat brain and rat 3Y1 fibroblast. They were splicing variants, and we named brain big one b-nexilin and fibroblast small one s-nexilin. b-Nexilin purified from rat brain was a protein of 656 amino acids (aa) with a calculated molecular weight of 78,392, whereas s-nexilin, encoded by the cDNA isolated from rat 3Y1 cells by the reverse transcriptase-PCR method, was a protein of 606 aa with a calculated molecular weight of 71,942. b-Nexilin had two F-actin- binding domains (ABDs) at the NH2-terminal and middle regions, whereas s-nexilin had one ABD at the middle region because 64 aa residues were deleted and 14 aa residues were inserted in the first NH2-terminal ABD of b-nexilin, and thereby the first ABD lost its activity. b- and s-nexilins bound along the sides of F-actin, but only b-nexilin showed F-actin cross-linking activity. b-Nexilin was mainly expressed in brain and testis, whereas s-nexilin was mainly expressed in testis, spleen, and fibroblasts, such as rat 3Y1 and mouse Swiss 3T3 cells, but neither b- nor s-nexilin was detected in liver, kidney, or cultured epithelial cells. An immunofluorescence microscopic study revealed that s-nexilin was colocalized with vinculin, talin, and paxillin at cell- matrix adherens junction (AJ) and focal contacts, but not at cell-cell AJ, in 3Y1 cells. Overexpressed b- and s-nexilins were localized at focal contacts but not at cell-cell AJ. These results indicate that nexilin is a novel F-actin-binding protein localized at cell-matrix AJ.


Asunto(s)
Actinas/metabolismo , Proteínas Portadoras/metabolismo , Proteínas de Microfilamentos/metabolismo , Empalme Alternativo , Secuencia de Aminoácidos , Animales , Encéfalo/metabolismo , Proteínas Portadoras/química , Proteínas Portadoras/genética , Adhesión Celular , Línea Celular , Clonación Molecular , ADN Complementario/genética , Matriz Extracelular/metabolismo , Inmunohistoquímica , Uniones Intercelulares/metabolismo , Masculino , Ratones , Proteínas de Microfilamentos/química , Proteínas de Microfilamentos/genética , Datos de Secuencia Molecular , Peso Molecular , Ratas , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Homología de Secuencia de Aminoácido , Distribución Tisular
8.
Science ; 229(4716): 874-7, 1985 Aug 30.
Artículo en Inglés | MEDLINE | ID: mdl-4023716

RESUMEN

The spectral sensitivities and color of oil droplets of cone photoreceptors in the retina of the red-eared turtle (Pseudemys scripta elegans) were investigated by intracellular recording and injections of Lucifer yellow dye. Six morphological types of cones could be distinguished by the color of the oil droplets located in the outermost inner segments. Single cones containing either red or pale green oil droplets were sensitive to red light, cones with yellow oil droplets to green, and cones with clear oil droplets to blue. Contrary to previous reports, both principal and accessory members of double cones were sensitive to red, and no diffusion of dye was detected between the two apposed members. Thus, the oil droplets provide a reliable morphological basis for further investigation of the neuroanatomical networks underlying the processing of color information in the vertebrate retina.


Asunto(s)
Lípidos/análisis , Células Fotorreceptoras/análisis , Tortugas/fisiología , Animales , Fluorescencia , Colorantes Fluorescentes , Isoquinolinas , Luz , Células Fotorreceptoras/fisiología , Espectrofotometría , Tortugas/anatomía & histología
9.
Clin Exp Dermatol ; 34(8): e597-8, 2009 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-19489865

RESUMEN

A 72-year-old man presented with a 1-month history of a rash. The eruption had previously been successfully treated with oral corticosteroids (prednisolone 30 mg/day) and antihistamines on two previous occasions, but recurred several days after stopping treatment. On examination, multiple, indurated, round to annular erythematous plaques were found on the trunk and limbs. Histological examination revealed interstitial oedema, a dense infiltrate of eosinophils in the dermis, and flame figure formation. These results led us to the diagnosis of eosinophilic cellulitis. Treatment with oral corticosteroids (prednisolone 15 mg/day) was unsuccessful. Four weeks after the start of oral tacrolimus 1 mg/day, the eruption completely resolved.


Asunto(s)
Celulitis (Flemón)/tratamiento farmacológico , Eosinofilia/tratamiento farmacológico , Inmunosupresores/uso terapéutico , Tacrolimus/uso terapéutico , Administración Oral , Anciano , Celulitis (Flemón)/patología , Eosinofilia/patología , Humanos , Masculino , Recurrencia , Resultado del Tratamiento
10.
Pediatr Hematol Oncol ; 25(6): 607-13, 2008 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-18728980

RESUMEN

A 20-year-old female developed a relapse of B-precursor acute lymphoblastic leukemia (ALL) as a mass in her left breast after 6 years of maintained continuous complete remission. No leukemic lesions were identified in other sites such as the bone marrow or cerebrospinal fluid. The relapsed leukemic cells in the breast revealed the same immunophenotypes (CD10(+), CD19(+), CD20(+), HLA-DR(+), CD34(+)) as those of the onset ALL cells in the bone marrow. A literature survey found 10 other cases of ALL relapse in the breast without bone marrow involvement, mostly consisting of adolescent girls. Including the present report, a total of 11 cases were analyzed; the onset ages of ALL were a median of 16.5 (range 5-50) years old and the ages of relapse in the breast a median of 20 (range 12-51) years old. Data suggest that, although rare, the breast could become one of the extramedullary relapse sites of ALL developed in adolescent girls.


Asunto(s)
Neoplasias de la Mama/secundario , Recurrencia Local de Neoplasia , Leucemia-Linfoma Linfoblástico de Células Precursoras B/patología , Adulto , Femenino , Humanos
11.
Transplant Proc ; 50(5): 1482-1488, 2018 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-29880375

RESUMEN

BACKGROUND: Several studies have suggested that decreased muscle volume is associated with attenuation of immune function. The recipient's immune system is responsible for rejection of transplanted organs, which is a major cause of graft loss after transplantation. We aimed to determine whether muscle volume is correlated with graft survival after pancreas transplantation (PT). METHODS: Forty-three patients underwent PT for type 1 diabetes mellitus at our institution from August 2001 to May 2016. The quantity of skeletal muscle was evaluated using the psoas muscle mass index (PMI). The correlation between PMI and outcome after PT was assessed. RESULTS: A total of 32 and 11 recipients underwent simultaneous pancreas-kidney transplantation (SPK) and PT alone/pancreas after kidney transplantation, respectively. Patients with a surviving graft showed a significantly lower PMI than those with graft loss (P = .0451). We divided the recipients into two groups according to the PMI cutoff values, which were established using receiver operating characteristic curves. The cumulative graft survival rate was significantly higher in patients with a low PMI (P = .0206). A multivariate Cox regression analysis revealed that a low PMI (P = .0075) is an independent predictive factor for better graft survival. A low PMI was not a significant predictive factor for acute rejection, but was an independent predictive factor for graft survival after the first acute rejection (P = .0025). CONCLUSIONS: Our data suggest that muscle volume could be a predictor of graft survival after PT.


Asunto(s)
Diabetes Mellitus Tipo 1/complicaciones , Diabetes Mellitus Tipo 1/cirugía , Supervivencia de Injerto/fisiología , Trasplante de Páncreas , Sarcopenia/complicaciones , Adulto , Área Bajo la Curva , Estudios de Cohortes , Femenino , Rechazo de Injerto , Humanos , Trasplante de Riñón , Masculino , Persona de Mediana Edad , Análisis Multivariante , Músculos Psoas/patología , Curva ROC , Estudios Retrospectivos , Sensibilidad y Especificidad
12.
Oncogene ; 25(12): 1807-11, 2006 Mar 16.
Artículo en Inglés | MEDLINE | ID: mdl-16331272

RESUMEN

Tumor suppressor p53 is known to play a crucial role in chemosensitivity in colorectal cancer. We previously demonstrated that an apoptosis-associated speck-like protein, ASC, is a p53-target gene which regulates p53-Bax mitochondrial apoptotic pathway. ASC is also known to be a target of methylation-induced gene silencing. An inactivation of ASC might thus cause resistance to chemotherapy, and if this is the case, then the expression of ASC would restore the chemosensitivity. The aim of this study was to clarify this hypothesis. ASC was methylated in 25% of all resected specimens in patients with colorectal cancer; however, ASC methylation did not always correspond to a lack of ASC protein. When expressed in colon cancer cells, in which ASC is absent due to methylation, ASC was found to enhance the chemosensitivity in a p53-dependent manner. In p53-null cells, ASC increased the p53-mediated cell death induced by p53-expressing adenovirus infection. Our data suggest that the methylation-induced silencing of ASC might cause resistance to p53-mediated chemosensitivity in colorectal cancer. The gene introduction of ASC may thus restore such chemosensitivity, and this modality may therefore be a useful new treatment strategy for colorectal cancer.


Asunto(s)
Neoplasias Colorrectales/genética , Proteínas del Citoesqueleto/genética , Metilación de ADN , Resistencia a Antineoplásicos/genética , Silenciador del Gen , Proteína p53 Supresora de Tumor/metabolismo , Antineoplásicos/farmacología , Apoptosis/efectos de los fármacos , Apoptosis/fisiología , Proteínas Adaptadoras de Señalización CARD , Neoplasias Colorrectales/tratamiento farmacológico , Neoplasias Colorrectales/metabolismo , Islas de CpG/genética , Proteínas del Citoesqueleto/metabolismo , Fluorouracilo/farmacología , Humanos , Reacción en Cadena de la Polimerasa
13.
Transplant Proc ; 49(5): 1133-1137, 2017 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-28583543

RESUMEN

BACKGROUND: Living pancreas transplantation plays an important role in the treatment of patients with severe type 1 diabetes. However, pancreatectomy is very invasive for the donor, and less-invasive surgical procedures are needed. Although some reports have described hand-assisted laparoscopic surgery for distal pancreatectomy in living-donor operations, less-invasive laparoscopy-assisted (LA) procedures are expected to increase the donor pool. We herein report the outcomes of four cases of LA spleen-preserving distal pancreatectomy (Warshaw technique [WT]) in living pancreas donors. PATIENTS AND METHODS: Four living pancreas donors underwent LA-WT at our institution from September 2010 to January 2013. All donors fulfilled the donor criteria established by the Japan Society for Pancreas and Islet Transplantation. RESULTS: The median donor age was 54 years. Two donors underwent left nephrectomy in addition to LA-WT for simultaneous pancreas-kidney transplantation. The median donor operation time for pancreatectomy was 340.5 minutes. The median pancreas warm ischemic time was 3 minutes. The median donor blood loss was 246 g. All recipients immediately achieved insulin independence. One donor required reoperation because of obstructive ileus resulting from a port-site hernia. Another donor developed a pancreatic fistula (International Study Group of Pancreatic Fistula grade B), which was controlled with conservative management. After a maximum follow-up of 73 months, no clinically relevant adverse events had occurred. These results were comparable with those of previous studies concerning living-donor pancreas transplantation. CONCLUSION: The LA-WT is a safe and acceptable operation for living-donor pancreas transplantation.


Asunto(s)
Laparoscopía/métodos , Donadores Vivos , Trasplante de Páncreas/métodos , Pancreatectomía/métodos , Recolección de Tejidos y Órganos/métodos , Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad , Páncreas/cirugía
14.
Neuroscience ; 137(2): 573-81, 2006.
Artículo en Inglés | MEDLINE | ID: mdl-16289884

RESUMEN

ATP-sensitive K channels are widely expressed in cytoplasmic membranes of neurons, and they couple cell metabolism to excitability. They are thought to be involved in neuroprotection against cell damage during hypoxia, ischemia and excitotoxicity by hyperpolarizing neurons and reducing excitability. Although barbiturates are often used in patients with brain ischemia, the effects of these agents on neuronal ATP-sensitive K channels have not been clarified. We studied the effects of thiopental and pentobarbital on surface ATP-sensitive K channels in principal neurons of rat substantia nigra pars compacta. Whole cell voltage- and current-clamp recordings were made using rat midbrain slices. ATP-sensitive K channels were activated by intracellular dialysis with an ATP-free pipette solution during perfusion with a glucose-free solution. When the pipette solution contained 4mM ATP and the perfusing solution contained 25 mM glucose, the membrane current at -60 mV remained stable. When intracellular ATP was depleted, hyperpolarization and an outward current developed slowly. Although thiopental did not affect the membrane current in the presence of ATP and glucose, it reversibly inhibited the hyperpolarization and outward current induced by intracellular ATP depletion at 100 and 300 microM. Thiopental reduced the ATP depletion-induced outward current by 4.7%, 36.7% and 87% at 30, 100 and 300 microM, respectively. The high dose of pentobarbital also exhibited similar effects on ATP-sensitive K channels. These results suggest that barbiturates at high concentrations but not at clinically relevant concentrations inhibit ATP-sensitive K channels activated by intracellular ATP depletion in rat substantia nigra.


Asunto(s)
Barbitúricos/farmacología , Neuronas/efectos de los fármacos , Canales de Potasio de Rectificación Interna/efectos de los fármacos , Potasio/metabolismo , Sustancia Negra/efectos de los fármacos , Adenosina Trifosfato/metabolismo , Adenosina Trifosfato/farmacología , Animales , Animales Recién Nacidos , Daño Encefálico Crónico/tratamiento farmacológico , Daño Encefálico Crónico/fisiopatología , Daño Encefálico Crónico/prevención & control , Membrana Celular/efectos de los fármacos , Membrana Celular/metabolismo , Relación Dosis-Respuesta a Droga , Hipnóticos y Sedantes/farmacología , Líquido Intracelular/efectos de los fármacos , Líquido Intracelular/metabolismo , Potenciales de la Membrana/efectos de los fármacos , Potenciales de la Membrana/fisiología , Inhibición Neural/efectos de los fármacos , Inhibición Neural/fisiología , Neuronas/metabolismo , Fármacos Neuroprotectores/farmacología , Técnicas de Cultivo de Órganos , Técnicas de Placa-Clamp , Pentobarbital/farmacología , Canales de Potasio de Rectificación Interna/metabolismo , Ratas , Ratas Sprague-Dawley , Sustancia Negra/metabolismo , Tiopental/farmacología
15.
Biochim Biophys Acta ; 939(2): 383-92, 1988 Apr 07.
Artículo en Inglés | MEDLINE | ID: mdl-3355823

RESUMEN

The effect of lipid peroxidation on the protein conformation of the porcine intestinal brush-border membranes was studied using a fluorogenic thiol reagent, N-[7-dimethylamino-4-methylcoumarinyl]maleimide (DACM). By a kinetic analysis of the reaction of the membranes with DACM, it was shown that the reaction rate of the SH groups (SHf) of the membrane proteins, whose reaction with the dye is very fast, decreases in proportion to the extent of thiobarbituric acid-reactive substance formation. The difference in the rate of the reaction of the SHf groups for DACM between the control and peroxidized membranes completely disappeared after denaturation of the proteins by treatment with guanidine hydrochloride. The reaction of DACM with the SHf groups of the control membranes accelerated when the temperature was increased with an apparent transition temperature between 25 degrees C and 30 degrees C. On the other hand, no transition was observed in the peroxidized membranes over the temperature range 20-43 degrees C. These results suggest that the conformation around the SHf groups of the proteins in the peroxidized membranes is apparently different from that in the control membranes. A modification of the conformation around the SH groups in the membrane proteins associated with lipid peroxidation was further demonstrated by finding that the quenching efficiency of the fluorescence of the DACM-labeled membranes by Tl+ was markedly decreased after lipid peroxidation. Based on these results, changes in the protein conformation of the porcine intestinal brush-border membranes by lipid peroxidation are discussed.


Asunto(s)
Intestino Delgado/ultraestructura , Peróxidos Lipídicos/metabolismo , Lípidos de la Membrana/metabolismo , Proteínas de la Membrana , Animales , Guanidina , Guanidinas/farmacología , Cinética , Maleimidas/metabolismo , Malondialdehído , Fluidez de la Membrana , Proteínas de la Membrana/metabolismo , Microvellosidades/metabolismo , Conformación Proteica , Desnaturalización Proteica/efectos de los fármacos , Espectrometría de Fluorescencia , Compuestos de Sulfhidrilo/metabolismo , Reactivos de Sulfhidrilo , Porcinos , Temperatura
16.
Biochim Biophys Acta ; 861(2): 311-8, 1986 Oct 09.
Artículo en Inglés | MEDLINE | ID: mdl-3756162

RESUMEN

The effect of lipid peroxidation on the lipid fluidity of porcine intestinal brush-border membranes was examined by measuring the rotational mobility and the accessibility to fluorescence quenchers (CH3COOT1, CuSO4 and KI) of pyrene or n-(9-anthroyloxy)stearic acid (n = 2 or 12) in the membranes. The harmonic mean of the rotational relaxation times of pyrene increased and the rate constants, kq, of the quenching reaction of pyrene and 2-(9-anthroyloxy)stearic acid incorporated in the membrane lipids decreased upon lipid peroxidation, indicating reduction of the lipid fluidity of the membranes by lipid peroxidation. In addition, the kq value of the reaction of 2-(9-anthroyloxy)stearic acid in the membranes with Cu2+ decreased in proportion to the amount of the products of lipid peroxidation. On the other hand, the kq value of the reaction of 12-(9-anthroyloxy)stearic acid with Cu2+ or I- was unaffected by lipid peroxidation. Based on these results, a localized change in the lipid fluidity of the membranes in association with lipid peroxidation has been discussed.


Asunto(s)
Peróxidos Lipídicos/metabolismo , Fluidez de la Membrana , Lípidos de la Membrana/metabolismo , Microvellosidades/metabolismo , Pirenos/metabolismo , Ácidos Esteáricos/metabolismo , Animales , Polarización de Fluorescencia , Colorantes Fluorescentes/metabolismo , Intestino Delgado/metabolismo , Cinética , Porcinos , Temperatura
17.
Biochim Biophys Acta ; 888(3): 332-7, 1986 Oct 10.
Artículo en Inglés | MEDLINE | ID: mdl-3756225

RESUMEN

Two proteins (Mr 46,000, pI 6.4 and 7.0), the phosphorylation of which was increased by any of the membrane-perturbing agents in parallel with activation of NADPH oxidase in intact guinea-pig polymorphonuclear leukocytes in our previous study (Okamura, N., Ohashi, S., Nagahisa, N. and Ishibashi, S. (1984) Arch. Biochem. Biophys. 228, 270-277), were also phosphorylated in a cell-free system prepared from the leukocytes. The in vitro phosphorylation of these two proteins was stimulated by the addition of phosphatidylserine in the presence of higher concentrations of Ca2+ (300-500 microM). The phosphorylation was further increased when protein kinase C partially purified from guinea-pig brain was added to the system. At a low concentration of Ca2+ (about 10 microM), stimulation of the phosphorylation was not attained by phosphatidylserine alone but required the addition of diacylglycerol or phorbol myristate acetate. On the other hand, the increase in the phosphorylation was inhibited by H-7, an inhibitor for protein kinase C. These results indicate that protein kinase C is involved in the phosphorylation of the two proteins, which may be related to the superoxide anion production stimulated by various membrane-perturbing agents.


Asunto(s)
NADH NADPH Oxidorreductasas/metabolismo , Neutrófilos/enzimología , Proteína Quinasa C/metabolismo , 1-(5-Isoquinolinesulfonil)-2-Metilpiperazina , Animales , Autorradiografía , Calcio/farmacología , Sistema Libre de Células/efectos de los fármacos , Clorpromazina/farmacología , Activación Enzimática , Femenino , Cobayas , Isoquinolinas/farmacología , NADPH Oxidasas , Neutrófilos/metabolismo , Fosfatidilserinas/farmacología , Fosforilación , Piperazinas/farmacología , Proteína Quinasa C/antagonistas & inhibidores , Proteínas/metabolismo , Sulfonamidas/farmacología , Acetato de Tetradecanoilforbol/farmacología
18.
Biochim Biophys Acta ; 1310(2): 223-32, 1996 Feb 02.
Artículo en Inglés | MEDLINE | ID: mdl-8611637

RESUMEN

T-cell receptor (TCR) triggering by an anti-CD3 antibody or phytohemagglutinin (PHA) as well as the treatment with phorbol myristate acetate (PMA), a direct activator of protein kinase C (PKC), induces activation of Ras in T-lymphocytes (Downward, J. et al. (1990)) Nature 364, 719-723). In this paper, we studied the role of Ras in the process of TCR-mediated T-cell activation using a human lymphomic Jurkat cell line. The stimulatory effect of TCR cross-linking on Ras activation was inhibited by herbimycin A, a specific inhibitor of protein tyrosine kinases (PTKs), whereas PMA-induced Ras activation was not affected. On the other hand, calphostin C, a specific inhibitor of PKC, blocked not only PMA-induced, but also TCR-mediated formation of Ras.GTP. Furthermore, down-regulation of PMA-sensitive PKC severely impaired the activation of Ras in response to TCR-stimulation. Tyrosine-phosphorylation and translocation to the particulate fraction of phospholipase C-gamma 1 (PLC-gamma 1) were observed upon T-cell activation. Subcellular localization of PKC was also changed when the cells were stimulated with an anti-CD3 antibody or PMA. While TCR-stimulated translocation of PKC was observed only transiently, PMA-induced translocation of PKC was more sustained. These results suggest that the activation of PLC-gamma 1 by PTK and subsequent activation of PKC are important for TCR-mediated Ras activation in Jurkat cells. An activated form of Ras enhanced the activation of interleukin 2 (IL-2) promoter by TCR stimulation or PMA treatment, although the activated Ras by itself was insufficient for IL-2 promoter activation. On the other hand, a dominant-inhibitory Ras diminished almost completely the activation of IL-2 promoter induced by PMA plus calcium ionophore, indicating that Ras is essential for transduction of T-cell activation signals. Cholera toxin (CTX), which directly activates Gs alpha, is shown to inhibit the activation of IL-2 promoter. TCR-mediated Ras activation, tyrosine phosphorylation and translocation of cellular proteins including ZAP-70, PLC-gamma 1 , and PKC. An activated Gs alpha mutant as well as dibutylyl cAMP (dBcAMP) also showed similar inhibitory effects.


Asunto(s)
AMP Cíclico/metabolismo , Activación de Linfocitos , Proteínas Tirosina Quinasas/metabolismo , Proteínas Proto-Oncogénicas p21(ras)/metabolismo , Linfocitos T/fisiología , Compartimento Celular , Línea Celular , Toxina del Cólera/farmacología , Inhibidores Enzimáticos/farmacología , Regulación de la Expresión Génica/efectos de los fármacos , Guanosina Difosfato/metabolismo , Guanosina Trifosfato/metabolismo , Humanos , Interleucina-2/genética , Fosfotirosina/metabolismo , Regiones Promotoras Genéticas , Proteínas Tirosina Quinasas/antagonistas & inhibidores , ARN Mensajero/genética , Receptores de Antígenos de Linfocitos T/fisiología , Transducción de Señal , Transcripción Genética , Fosfolipasas de Tipo C/metabolismo , Proteína Tirosina Quinasa ZAP-70
19.
Biochim Biophys Acta ; 817(1): 181-6, 1985 Jul 11.
Artículo en Inglés | MEDLINE | ID: mdl-4005254

RESUMEN

Effects of ionic strength and temperature on the interaction between Tb3+ and porcine intestinal brush-border membrane vesicles were studied. When Tb3+ was added to the vesicle suspension, Tb3+ fluorescence increased with increasing concentration of Tb3+, showing a saturation. The apparent dissociation constant of one of at least two components of this binding reaction was estimated to be about 12.5 microM at 25 degrees C, pH 7.4. But the affinity of Tb3+ for the membrane vesicles was variable with changes of ionic strength and temperature. The affinity was lowered by addition of KCl to medium and by increase of temperature above 30 degrees C. In addition, temperature-induced change in the affinity of Tb3+ for the membranes was reversible over a temperature range from 13 to 46 degrees C. Temperature-dependence profiles of the excimer formation efficiency of pyrene-labeled membranes and of the harmonic mean of the rotational relaxation times of pyrene molecules in the membranes revealed that the phase transition of the membrane lipids occurs at about 30 degrees C. Based on these results, characteristics of Tb3+ binding to the membranes are discussed in relation to the nature of lipid phase and surface charges of the membranes.


Asunto(s)
Mucosa Intestinal/metabolismo , Microvellosidades/metabolismo , Terbio/metabolismo , Animales , Cinética , Concentración Osmolar , Espectrometría de Fluorescencia , Porcinos , Temperatura , Termodinámica
20.
Biochim Biophys Acta ; 1292(1): 69-76, 1996 Jan 04.
Artículo en Inglés | MEDLINE | ID: mdl-8547351

RESUMEN

The susceptibility of alpha-lactalbumin to transglutaminase reactions was studied using an enzyme from Streptoverticillium which can catalyze the reactions irrespective of the presence or absence of Ca2+. Transglutaminase-catalyzed polymerization of alpha-lactalbumin in the native state occurred to a very limited extent. Transformation from the native state to the molten globule state brought about by Ca(2+)-removal from holo-alpha-lactalbumin enhanced the polymerization of the protein catalyzed by transglutaminase. The incorporation of Carbobenzoxy-Gln-Gly into alpha-lactalbumin through the enzyme reaction was investigated to determine the amounts of lysine residues which are present at molecular surface and available to the enzyme. There was no significant difference in the amount of available lysine residues between the native and the molten globule molecule. However, the amount of surface glutamine residues incorporated with monodansylcadaverine by transglutaminase was remarkably higher in the molten globule state than that in the native state. The monodansylcadaverine-incorporated site of alpha-lactalbumin in the molten globule state was identified as Gln-54 by amino-acid sequence analysis of fluorescence-labeled peptides separated from chymotryptic digests of the protein. Possible reason for selective labeling of Gln-54 in molten globule alpha-lactalbumin was proposed.


Asunto(s)
Lactalbúmina/metabolismo , Transglutaminasas/metabolismo , Secuencia de Aminoácidos , Amoníaco/metabolismo , Animales , Calcio/farmacología , Bovinos , Cromatografía en Gel , Cromatografía Líquida de Alta Presión , Compuestos de Dansilo/metabolismo , Dipéptidos/metabolismo , Electroforesis en Gel de Poliacrilamida , Fluorescencia , Glutamina/análisis , Glutamina/metabolismo , Lactalbúmina/química , Lisina/análisis , Lisina/metabolismo , Datos de Secuencia Molecular , Peso Molecular , Conformación Proteica , Desnaturalización Proteica , Pliegue de Proteína , Estructura Secundaria de Proteína , Streptomycetaceae/enzimología
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