Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 450
Filtrar
1.
Clin Nephrol ; 72(3): 211-5, 2009 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-19761727

RESUMO

We report a 56-year-old man with microscopic polyangiitis (MPA) who developed acute exacerbation of a chronic subdural hematoma (SDH). Laboratory data demonstrated elevation of myeloperoxidase antineutrophil cytoplasmic antibody (MPOANCA) and rapidly progressing renal dysfunction. Renal biopsy showed crescentic glomerulonephritis (GN) with membranous nephropathy (MN). He was treated with corticosteroids, antithrombotic agents, and an immunosuppressant. One month after initiation of treatment, he had a mild headache. One month later, he developed acute SDH. Although he recovered completely after the operation, he finally died of bacterial infection. On autopsy, a scar of vasculitis was confirmed in the leptomeninges as well as in the kidney and lung. Although SDH is a rare complication in MPA, nephrologists must pay more attention to the initial symptoms before a hematoma attack such as headache, especially in patients using antithrombotic agents.


Assuntos
Fibrinolíticos/efeitos adversos , Hematoma Subdural Agudo/etiologia , Hematoma Subdural Crônico/etiologia , Poliangiite Microscópica/complicações , Humanos , Masculino , Pessoa de Meia-Idade
2.
J Clin Invest ; 99(6): 1361-6, 1997 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-9077546

RESUMO

The apolipoprotein(a) (apo[a]) gene encodes a protein component of lipoprotein(a) [Lp(a)] whose plasma levels vary widely among individuals. Hyper-Lp(a)-emia constitutes a risk factor for thromboembolic disease. We previously subclassified the apo(a) gene into four allelic types (A-D) by polymorphisms in the 5'-flanking region. To elucidate whether these polymorphisms affect the expression of apo(a), we measured plasma Lp(a) concentrations in vivo by ELISA and examined expression of the gene by an in vitro assay using its 5'-flanking region. Homozygotes of type C had significantly higher Lp(a) levels than those of type D. The relative expression of type C was also about three times higher than that of type D, which was consistent with the in vivo results. Deletion analysis revealed that the substitution of C by T (+93) led to negative regulation in expression of the gene, while the change of G to A (+121) led to positive regulation. These results indicate that the polymorphisms in the 5'-flanking region of the apo(a) gene affect the efficiency of its expression and, in part, play a role in regulating plasma Lp(a) levels.


Assuntos
Apolipoproteína A-I/genética , Regulação da Expressão Gênica , Lipoproteína(a)/sangue , Polimorfismo Genético , Sequências Reguladoras de Ácido Nucleico , Alelos , Cloranfenicol O-Acetiltransferase/genética , Deleção de Genes , Humanos , Regiões Promotoras Genéticas
3.
J Neuroimmunol ; 185(1-2): 195-200, 2007 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-17335908

RESUMO

Recently, we discovered autoantibodies against the amino (NH(2))-terminal of alpha-enolase (NAE) in patients with Hashimoto's encephalopathy (HE) (83.3%; 5/6) [Fujii, A., Yoneda, M., Ito, T., Yamamura, O., Satomi, S., Higa, H., Kimura, M., Suzuki, M., Yamashita, M., Yuasa, T., Suzuki, H., Kuriyama, M., 2005. Autoantibodies against the amino terminal of alpha-enolase are a useful diagnostic marker of Hashimoto's encephalopathy. J. Neuroimmunol. 162, 130-136]. We further investigated the anti-NAE autoantibodies in 25 patients who fit the diagnostic criteria for HE, based on the presence of anti-thyroid antibodies and responsiveness to immunotherapy. In this study, we demonstrated a high prevalence (68%, 17 of 25) and high specificity of anti-NAE autoantibodies in patients with HE, and clarified the clinical features of HE. This result demonstrated that anti-NAE autoantibodies, in addition to anti-thyroid autoantibodies, are emphasized as useful serological diagnostic markers of HE.


Assuntos
Autoanticorpos/sangue , Encefalopatias/etiologia , Encefalopatias/imunologia , Doença de Hashimoto/complicações , Fosfopiruvato Hidratase/imunologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Western Blotting , Encefalopatias/sangue , Eletroforese em Gel de Poliacrilamida , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fosfopiruvato Hidratase/química , Prevalência
4.
Dig Liver Dis ; 39(5): 422-9, 2007 May.
Artigo em Inglês | MEDLINE | ID: mdl-17379587

RESUMO

BACKGROUND: The effectiveness of leukocytapheresis against ulcerative colitis has been reported. However, the efficacy of this therapy for steroid-resistant ulcerative colitis patients has hardly been examined. AIMS: The aims of this study are to evaluate the efficacy of leukocytapheresis for steroid-resistant ulcerative colitis patients and to identify clinical factors that predict the efficacy of this therapy for these patients. METHODS: Clinical factors of 71 steroid-resistant ulcerative colitis patients who underwent leukocytapheresis analysed. RESULTS: Of those analysed, 53 (75%) patients showed an initial response to leukocytapheresis. Among cases with initial response, however, only 19 (27%) patients maintained remission for more than 6 months. Steroid-dependent course (Odds ratio =5.53, 95% confidence interval; 1.24-24.73) and a high C-reactive protein degree (Odds ratio=1.6, confidence interval; 1.09-2.35) were predictors of initial response to leukocytapheresis. Rapid response, which means remission induction within three leukocytapheresis sessions, was the only predictor of maintenance of remission for more than 6 months after successful leukocytapheresis therapy (odds ratio=8.01, confidence interval; 1.08-59.37). CONCLUSIONS: Leukocytapheresis was effective for steroid-resistant ulcerative colitis patients. However, relapse was frequently observed within short periods after the initial response to this therapy. Patients without a rapid response should be treated with alternative or additional therapies.


Assuntos
Colite Ulcerativa/terapia , Leucaférese , Adolescente , Adulto , Idoso , Criança , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Esteroides/uso terapêutico , Resultado do Tratamento
5.
J Natl Cancer Inst ; 66(1): 37-42, 1981 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-6935463

RESUMO

Specificity of a previously reported prostate antigen (PA) was assessed by several immunologic procedures. This antigen, restricted in distribution to the prostate gland, was detected within ductal epithelial cells. Continuous established cell lines LNCaP and PC-3 of malignant prostate origin retained the expression of PA. Tumor cells released the antigen in vitro into the culture fluid and also in vivo into the circulation of nude mice preinoculated with LNCaP cells. Prostate cells in culture also specifically accreted immunoglobulin fragments of PA antiserum.


Assuntos
Próstata/imunologia , Animais , Especificidade de Anticorpos , Antígenos de Neoplasias , Linhagem Celular , Células Cultivadas , Reações Cruzadas , Epitélio/imunologia , Humanos , Masculino , Camundongos , Camundongos Nus , Transplante de Neoplasias , Neoplasias da Próstata/imunologia
6.
J Natl Cancer Inst ; 68(1): 99-105, 1982 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-6172628

RESUMO

Serum prostate-specific antigen and prostatic acid phosphatase were simultaneously evaluated in 22 healthy males, 29 patients with benign prostatic hypertrophy, and 192 patients with prostate cancers at various stages as well as in 30 patients with cancers other than prostate cancer. Both markers were quantitated by specific sandwich-type, enzyme-linked, immunosorbent assays with the use of specific antiserum reagents. Serum assays revealed a discordance between these two markers; thus expressions of these two biochemically and immunologically distinct prostate-specific proteins may reflect different aspects in the biology of prostate cancer. A combination test with the use of 7.5 ng of prostate antigen and 15.5 ng of prostatic acid phosphatase/ml of serum, respectively, as cutoff values resulted in a positive detection rate of 58% for prostate cancers of stages A (7/12) and B (21/36) each, 68% for prostate cancer of stage C (19/28), 92% for prostate cancer of stage D (106/116), and only 10% for benign prostatic hypertrophy (3/29). None of 52 other cancers or healthy controls was registered as positive. This study demonstrates that a multiple marker test of tissue-specific antigens can be of an additive value in the immunodiagnosis of cancer and may be a logical and effective approach at this time, in light of the unavailability of human tumor-specific markers.


Assuntos
Fosfatase Ácida/sangue , Antígenos de Neoplasias/análise , Hiperplasia Prostática/imunologia , Neoplasias da Próstata/diagnóstico , Adulto , Idoso , Ensaio de Imunoadsorção Enzimática , Humanos , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Hiperplasia Prostática/sangue , Neoplasias da Próstata/sangue , Neoplasias da Próstata/imunologia , Valores de Referência
7.
Cancer Res ; 40(12): 4658-62, 1980 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-6159971

RESUMO

A sensitive sandwich-type enzyme immunoassay has been developed for quantitation of a human prostate-specific antigen (PA). With this method, PA at a concentration as low as 0.10 ng/ml can be detected. The assay was reproducible as within and between assays yielded a coefficient of variation of 5.7% and 4.6%, respectively. Only human prostate tissues (n = 31) were shown to contain PA. No PA was detected in other human normal or tumor tissues (n = 13). PA was not detectable in sera from normal females (n = 17) or female cancer patients (n = 25). A mean +/- S.D. of 0.47 +/- 0.661 ng/ml (ranging from less than 0.10 to 2.6) ws obtained from a group of 51 normal males. Sera from male patients with nonprostatic cancer contained a similar range of PA as that of normal males. Patients with prostate cancer (371 of 442) and benign prostatic hypertrophy (13 of 19) were shown to have elevated levels of circulating PA. Although no quantitative difference in PA levels was found between the benign prostatic hypertrophy group and Stage A of prostatic cancer, patients with Stages C and D prostatic cancer exhibited significantly elevated levels of PA qualitatively and quantitatively. These results therefore indicate that PA is a histiotypic product of the prostate and may be of use as an adjunctive tool in diagnostic procedures of prostate cancer.


Assuntos
Antígenos/análise , Próstata/imunologia , Hiperplasia Prostática/imunologia , Neoplasias da Próstata/imunologia , Humanos , Técnicas Imunoenzimáticas , Masculino
8.
Cancer Res ; 41(10): 3874-6, 1981 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-7284995

RESUMO

The newly reported human prostate-specific antigen (PA) is a specific histiotypic product of human prostate. With the use of a sensitive enzyme immunoassay, the circulating PA in prostatic cancer patients has been evaluated clinically. In 96 patients with advanced stage of disease (D2) and receiving chemotherapies, the pretreatment serum PA levels were found to be of prognostic value with regard to the patient survival. Ten patients with metastatic prostate cancer were monitored for more than 32 weeks by 183 serial PA values and were found generally to respond to the treatment. Additionally, in another group of 32 patients who underwent curative therapies for localized prostate cancer, 161 serum samples were evaluated during periods of 12 to 114 weeks (average 56 weeks). Of these patients, five developed metastases during follow-up, and all were shown to exhibit increasingly elevated PA values, either corresponding to or preceding the clinical diagnosis of disease recurrence. These results suggest that PA is a new marker with potential value to merit further clinical study.


Assuntos
Próstata/imunologia , Neoplasias da Próstata/diagnóstico , Antígenos de Neoplasias/análise , Ensaio de Imunoadsorção Enzimática , Humanos , Masculino , Metástase Neoplásica , Especificidade de Órgãos , Prognóstico
9.
Cancer Res ; 44(8): 3604-7, 1984 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-6744282

RESUMO

A pancreas cancer-associated antigen (PCAA) and a pancreas-specific antigen (PaA) were simultaneously quantitated by enzyme-linked immunosorbent assays in serum specimens from 51 normal controls, 76 pancreatic cancers, 194 nonpancreatic cancers, and 22 benign pancreatic diseases. Primary immunological reagents used in the enzyme-linked immunosorbent assays were our polyclonal antibodies produced in rabbits against purified PCAA and PaA. Results revealed discordance of these two markers in pancreatic cancer, suggesting that the presence of these two biochemically and immunologically distinct pancreas proteins in patients' serum may reflect different biological aspects of cancer. The combination test resulted in a better sensitivity and specificity for pancreatic cancer, 90 and 85%, respectively, than either PCAA or PaA assay alone. This study demonstrated that the combination of serum PCAA and PaA tests yields an additive clinical value and may be a useful adjunctive aid for the immunodiagnosis of the pancreatic cancer.


Assuntos
Antígenos de Neoplasias/análise , Pâncreas/imunologia , Pancreatopatias/imunologia , Neoplasias Pancreáticas/imunologia , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Masculino , Neoplasias/imunologia , Valores de Referência
10.
Cancer Res ; 45(2): 886-91, 1985 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-2578313

RESUMO

To evaluate the prognostic value of prostate-specific antigen (PA) for detection of tumor growth after definitive therapy, 602 sera from 70 patients with stages B2 to D1 prostate cancer (26 of whom recurred) were analyzed in a blind study. Using Cox's proportional-hazards model, a highly significant association was found between serially measured PA and disease-free survival time (p = 0.0002). A positive predictive value of 100% was found for some markedly elevated PA levels and confirmed recurrence of disease. In fact, this study suggested that once a PA level of 88 ng/ml was reached, there was an average time of less than 2 months before a recurrence was clinically confirmed. Tumor growth in patients who recurred was indicated by a PA elevation before recurrence in 92% (24 of 26) as opposed to 20% (9 of 44) in disease-free patients. Additionally, in these 24 of 26 patients, levels of PA were elevated 12 months (mean lead time) before a confirmed disease recurrence. In patients who were still disease free, serial PA appeared to increase concurrently with putative tumor growth as shown by the initial surgical stage. Generally, the greater the PA level the more advanced was the stage of disease (B2 to D1). These data suggest that PA may be a useful adjuvant marker for monitoring tumor growth in patients with regionally confined prostate cancer.


Assuntos
Antígenos de Neoplasias/análise , Neoplasias da Próstata/análise , Humanos , Masculino , Estadiamento de Neoplasias , Prognóstico , Antígeno Prostático Específico , Neoplasias da Próstata/mortalidade , Fatores de Tempo
11.
Biochim Biophys Acta ; 662(2): 220-5, 1981 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-7317438

RESUMO

We describe the partial characterization and some properties of fibroblast and leucocyte neuraminidase towards 2 leads to 3 and 2 leads to 6 sialyllacose, and 2 leads to 3 and 2 leads to 6 sialylhexasaccharide which were isolated from the urine of a patient with adult sialidosis with partial beta-galactosidase deficiency. Neuraminidase activities were assayed using the radioactive-labeled derivatives of these saccharide substrates. These neuraminidases (acylneuraminyl hydrolase, EC 3.2.1.18) were partially inactivated by homogenization, sonication and freeze-thawing treatment. The leucocyte neuraminidase was more labile than that of fibroblasts. Fibroblast neuraminidase had about a 10-fold higher activity than leucocyte neuraminidase towards the respective substrates. The neuraminidase from fibroblasts and leucocytes were each able to hydrolyze 2 leads to 3 isomers 2-3 times faster than 2 leads to 6 isomers and the sialyllactoses 1.5-3.0-times faster than sialylhexasaccharides. Neuraminidase activities towards all four substrates were deficient in fibroblasts and leucocytes from the patients with adult sialidosis. Loss of activity was especially prominent in fibroblasts, while considerable residual activities (about 20-30%) remaining in leucocytes. In mucolipidosis II and III patients, these neuraminidase activities showed normal levels in leucocytes, although they were decreased in fibroblasts. The discrepancy between neuraminidase activities towards 2 leads to 3 and 2 leads to 6 isomers was not found in all the cases.


Assuntos
Mucolipidoses/metabolismo , Neuraminidase/metabolismo , Oligossacarídeos/urina , Pele/enzimologia , Adulto , Configuração de Carboidratos , Sequência de Carboidratos , Células Cultivadas , Fibroblastos/enzimologia , Humanos , Concentração de Íons de Hidrogênio , Cinética , Neuraminidase/deficiência , Especificidade por Substrato
12.
Biochim Biophys Acta ; 834(3): 396-401, 1985 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-2986706

RESUMO

We analyzed lipids from leukemic cells of two patients with adult T-cell leukemia and compared them with those from T-cell lymphocytes of normal subjects. The neutral glycosphingolipids and gangliosides which were isolated were characterized by thin-layer chromatography and neuraminidase treatment. Both leukemic cells and normal lymphocytes had monoglycosylceramide and diglycosylceramide as major neutral glycosphingolipids. In one patient, diglycosylceramide was markedly increased. II3NeuAc-LacCer (GM3) and more complex gangliosides were detected in both cells. The most characteristic finding in leukemic cells was the occurrence of a disialylated ganglioside, II3(NeuAc)2-LacCer (GD3), which is not found in normal lymphocytes and neutrophils. This ganglioside may be due to the induced synthesis in association with malignant transformation.


Assuntos
Glicoesfingolipídeos/metabolismo , Infecções por Retroviridae/metabolismo , Linfócitos T/metabolismo , Membrana Celular/metabolismo , Cromatografia em Camada Fina , Deltaretrovirus , Gangliosídeos/metabolismo , Humanos
13.
J Neuroimmunol ; 162(1-2): 130-6, 2005 May.
Artigo em Inglês | MEDLINE | ID: mdl-15833368

RESUMO

We investigated autoantibodies and their epitope(s) in Hashimoto's encephalopathy associated with Hashimoto's thyroiditis. In a proteomic analysis, they proved to recognize alpha-enolase. We further searched the epitope region in alpha-enolase using different regions of recombinant proteins expressed in cultured human cells. The amino terminal region was recognized by autobodies from a much higher proportion of patients with Hashimoto's encephalopathy (83.3%; 5/6) than from patients with Hashimoto's thyroiditis (11.8%; 2/17), and not at all by sera from controls (25 healthy individuals and 25 controls with other neurological disorders) (0%; 0/50). Neither the carboxyl terminal nor the mid-region of alpha-enolase showed specificity for Hashimoto's encephalopathy. Autoantibodies against the amino terminal of alpha-enolase are a useful diagnostic marker for Hashimoto's encephalopathy.


Assuntos
Autoanticorpos , Proteínas de Ligação a DNA/imunologia , Fosfopiruvato Hidratase/imunologia , Tireoidite Autoimune/diagnóstico , Proteínas Supressoras de Tumor/imunologia , Adulto , Idoso , Autoanticorpos/sangue , Biomarcadores , Biomarcadores Tumorais , Western Blotting/métodos , Encéfalo/metabolismo , Células Cultivadas , Proteínas de Ligação a DNA/sangue , Proteínas de Ligação a DNA/química , Ecocardiografia/métodos , Epitopos/imunologia , Epitopos/metabolismo , Feminino , Humanos , Pessoa de Meia-Idade , Fosfopiruvato Hidratase/sangue , Fosfopiruvato Hidratase/química , Proteínas Recombinantes/isolamento & purificação , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Tireoidite Autoimune/sangue , Tireoidite Autoimune/imunologia , Proteínas Supressoras de Tumor/sangue , Proteínas Supressoras de Tumor/química
14.
Mol Ecol Resour ; 15(1): 68-80, 2015 01.
Artigo em Inglês | MEDLINE | ID: mdl-24943089

RESUMO

Marine planktonic copepods are an ecologically important group with high species richness and abundance. Here, we propose a new metagenetic approach for revealing the community structure of marine planktonic copepods using 454 pyrosequencing of nuclear large subunit ribosomal DNA. We determined an appropriate similarity threshold for clustering pyrosequencing data into molecular operational taxonomic units (MOTUs) using an artificial community containing 33 morphologically identified species. The 99% similarity threshold had high species-level resolution for MOTU clustering but overestimated species richness. The artificial community was appropriately clustered into MOTUs at 97% similarity, with little inflation in MOTU numbers and with relatively high species-level resolution. The number of sequence reads of each MOTU was correlated with dry weight of that taxon, suggesting that sequence reads could be used as a proxy for biomass. Next, we applied the method to field-collected samples, and the results corresponded reasonably well with morphological analysis of these communities. Numbers of MOTUs were well correlated with species richness at 97% similarity, and large numbers of sequence reads were generally observed in MOTUs derived from species with large biomass. Further, MOTUs were successfully classified into taxonomic groups at the family level at 97% similarity; similar patterns of species richness and biomass were revealed within families with metagenetic and morphological analyses. At the 99% similarity threshold, MOTUs with high proportions of sequence reads were identified as biomass-dominant species in each field-collected sample. The metagenetic approach reported here can be an effective tool for rapid and comprehensive assessment of copepod community structure.


Assuntos
Biota , Copépodes/classificação , Copépodes/genética , Metagenômica , Animais , Análise por Conglomerados , Copépodes/anatomia & histologia , DNA Ribossômico/química , DNA Ribossômico/genética , Dados de Sequência Molecular , Filogenia , RNA Ribossômico/genética , Água do Mar , Análise de Sequência de DNA
15.
J Neuropathol Exp Neurol ; 56(8): 922-32, 1997 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-9258262

RESUMO

The results of well-characterized two-site enzyme immunoassays showed that the crude leptomeninges (consisting of the pia matter, arachnoid matter, and leptomeningeal vessels [LV]) from aged control brains and brains affected by Alzheimer disease (AD) contain very high levels of amyloid beta-protein (A beta). To learn about the source of A beta, we carefully dissected out both leptomeninges (LM) and LV under a dissecting microscope and determined the levels of soluble A beta in each. The purity of these dissected tissues was confirmed by the absence or presence of alpha-smooth muscle actin representing LV by Western blotting. Surprisingly, the amounts of A beta in each dissected sample were nearly equivalent on a weight basis. In each compartment from aged controls the level of A beta 1-42 was comparable to that of A beta 1-40, while in AD brain A beta 1-40 was a predominant species in both LM and LV. In some cases careful immunocytochemical examination revealed the presence of A beta deposits that were immunolabeled by several A beta monoclonal antibodies in leptomeningeal layers (most often in the arachnoid matter). The extent of A beta deposition in LM appeared to be much less than that explained by the soluble A beta levels, suggesting that immunocytochemically undetectable A beta can accumulate in LM. These observations indicate that leptomeninges are a large reservoir of A beta in normal aged individuals and in AD patients.


Assuntos
Envelhecimento/metabolismo , Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/metabolismo , Aracnoide-Máter/metabolismo , Pia-Máter/metabolismo , Adulto , Idoso , Idoso de 80 Anos ou mais , Aracnoide-Máter/irrigação sanguínea , Aracnoide-Máter/citologia , Vasos Sanguíneos/metabolismo , Células Cultivadas , Humanos , Imuno-Histoquímica , Neoplasias Meníngeas/metabolismo , Neoplasias Meníngeas/patologia , Meningioma/metabolismo , Meningioma/patologia , Pessoa de Meia-Idade , Pia-Máter/irrigação sanguínea , Pia-Máter/citologia , Testes de Precipitina , Solubilidade
16.
Endocrinology ; 139(3): 1329-37, 1998 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-9492069

RESUMO

The morphogenesis and remodeling of bone depends on the integrated activity of osteoblasts that form bone and osteoclasts that resorb bone. We previously reported the isolation of a new cytokine termed osteoclastogenesis inhibitory factor, OCIF, which specifically inhibits osteoclast development. Here we report the cloning of a complementary DNA of human OCIF. OCIF is identical to osteoprotegerin (OPG), a soluble member of the tumor-necrosis factor receptor family that inhibits osteoclastogenesis. Recombinant human OPG/OCIF specifically acts on bone tissues and increases bone mineral density and bone volume associated with a decrease of active osteoclast number in normal rats. Osteoblasts or bone marrow-derived stromal cells support osteoclastogenesis through cell-to-cell interactions. A single class of high affinity binding sites for OPG/OCIF appears on a mouse stromal cell line, ST2, in response to 1,25-dihydroxyvitamin D3. An anti-OPG/OCIF antibody that blocks the binding abolishes the biological activity of OPG/OCIF. When the sites are blocked with OPG/OCIF, ST2 cells fail to support osteoclastogenesis. These results suggest that the sites are involved in cell-to-cell signaling between stromal cells and osteoclast progenitors and that OPG/OCIF inhibits osteoclastogenesis by interrupting the signaling through the sites.


Assuntos
Glicoproteínas/fisiologia , Osteoclastos/fisiologia , Receptores Citoplasmáticos e Nucleares , Receptores do Fator de Necrose Tumoral/fisiologia , Sequência de Aminoácidos , Animais , Densidade Óssea/efeitos dos fármacos , Remodelação Óssea , Células Cultivadas , Clonagem Molecular , Glicoproteínas/genética , Humanos , Masculino , Camundongos , Dados de Sequência Molecular , Osteoclastos/efeitos dos fármacos , Osteoprotegerina , Ratos , Ratos Sprague-Dawley , Receptores do Fator de Necrose Tumoral/genética , Proteínas Recombinantes/farmacologia
17.
FEBS Lett ; 438(3): 289-92, 1998 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-9827563

RESUMO

Our previous studies have shown that the HMG-CoA reductase inhibitor (HCRI) causes rhabdomyolysis and electrical myotonia in rabbits and also kills L6 myoblasts in culture. In the present study, we analyzed the intracellular signal transduction pathway of HCRI-induced cell death using L6 myoblasts as a model system. Here, we report that simvastatin, a lipophilic HCRI, efficiently inhibited isoprenylation of Ras proteins and therefore induced translocation of a significant part of Ras proteins from the membrane fraction into the cytosolic fraction within 10 min. With this translocation, PI 3-kinase activity of the Ras-bound form both in total and in the membrane fraction was also decreased profoundly. Furthermore, various PI 3-kinase inhibitors also caused cell death with morphological changes similar to those caused by simvastatin. These results might represent the molecular events of HCRI-induced cell death, and suggest the significance of PI 3-kinase activity of the Ras-bound form in the maintenance of cell viability.


Assuntos
Morte Celular/efeitos dos fármacos , Inibidores de Hidroximetilglutaril-CoA Redutases/farmacologia , Fibras Musculares Esqueléticas/fisiologia , Fosfatidilinositol 3-Quinases/metabolismo , Sinvastatina/farmacologia , Animais , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Cinética , Fibras Musculares Esqueléticas/efeitos dos fármacos , Fibras Musculares Esqueléticas/enzimologia , Coelhos , Transdução de Sinais/efeitos dos fármacos
18.
FEBS Lett ; 444(1): 85-9, 1999 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-10037153

RESUMO

Our previous studies have shown that the HMG-CoA reductase (HCR) inhibitor (HCRI), simvastatin, causes myopathy in rabbits and kills L6 myoblasts. The present study was designed to elucidate the molecular mechanism of HCRI-induced cell death. We have demonstrated that simvastatin induces the tyrosine phosphorylation of several cellular proteins within 10 min. These phosphorylations were followed by apoptosis, as evidenced by the occurrence of internucleosomal DNA fragmentation and by morphological changes detected with Nomarski optics. Simvastatin-induced cell death was prevented by tyrosine kinase inhibitors. The MTT assay revealed that the addition of mevalonic acid into the culture medium partially inhibited simvastatin-induced cell death. Thus, these results suggested that protein tyrosine phosphorylation might play an important role in the intracellular signal transduction pathway mediating the HCRI-induced death of myoblasts.


Assuntos
Apoptose/efeitos dos fármacos , Inibidores de Hidroximetilglutaril-CoA Redutases/farmacologia , Músculo Esquelético/citologia , Fosfotirosina/metabolismo , Animais , Benzoquinonas , Linhagem Celular , Tamanho Celular/efeitos dos fármacos , Fragmentação do DNA/efeitos dos fármacos , Genisteína/farmacologia , Lactamas Macrocíclicas , Ácido Mevalônico/farmacologia , Peso Molecular , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/metabolismo , Fosforilação/efeitos dos fármacos , Pravastatina/farmacologia , Proteínas Tirosina Fosfatases/metabolismo , Proteínas Tirosina Quinases/antagonistas & inibidores , Quinonas/farmacologia , Ratos , Rifabutina/análogos & derivados , Transdução de Sinais/efeitos dos fármacos , Sinvastatina/antagonistas & inibidores , Sinvastatina/farmacologia , Fatores de Tempo
19.
FEBS Lett ; 446(1): 91-4, 1999 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-10100621

RESUMO

Our previous studies have shown that the HMG-CoA reductase (HCR) inhibitor (HCRI), simvastatin, kills L6 myoblasts by involving Ca2+ mobilization from the Ca2+ pool in the cells but not by influx from extracellular space. More recently, we found that HCRI induced tyrosine phosphorylation of several cellular proteins, followed by apoptotic cell death of L6 myoblasts. The present study was aimed to elucidate the molecular target(s) of these tyrosine phosphorylations induced by HCRI and demonstrated that simvastatin induces tyrosine phosphorylation of phospholipase C (PLC) gamma1. This tyrosine phosphorylation of PLC-gamma1 caused the increment of the intracellular inositol triphosphate (IP3) levels in L6 myoblasts. Pretreatment of the cells with herbimycin A, a specific inhibitor of protein tyrosine kinase, inhibited a simvastatin-induced increase in IP3 level in the cells as well as tyrosine phosphorylation of PLC-gamma1. Interestingly, pretreatment of the cells with U-73122, a specific inhibitor of PLC, prevented simvastatin-induced cell death. Thus, these results strongly suggest that simvastatin-induced tyrosine phosphorylation of PLC-gamma1 plays, at least in part, an important role for the development of simvastatin-induced cell death.


Assuntos
Apoptose/efeitos dos fármacos , Inibidores de Hidroximetilglutaril-CoA Redutases/farmacologia , Isoenzimas/metabolismo , Músculo Esquelético/patologia , Sinvastatina/farmacologia , Fosfolipases Tipo C/metabolismo , Animais , Linhagem Celular , Músculo Esquelético/enzimologia , Fosfolipase C gama , Fosforilação , Transdução de Sinais , Tirosina/metabolismo
20.
FEBS Lett ; 508(1): 53-6, 2001 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-11707267

RESUMO

Previous studies from this laboratory have shown that 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor (HCRI) causes apoptotic cell death of a muscle cell-derived cell line, L6 myoblasts, by involving the phosphatidylinositol-3 (PI-3) kinase pathway and tyrosine phosphorylation of several cellular proteins, although the relationship between PI-3 kinase pathway and tyrosine phosphorylation responses remained to be elucidated. Here, we show that HCRI induces tyrosine phosphorylation of catalytic subunit p110 of PI-3 kinase as early as 5 min after addition of HCRI into culture medium. We could not detect the tyrosine phosphorylation of the regulatory subunit p85 of PI-3 kinase under the present experimental conditions. Concomitantly, the kinase activity toward PI in p110 immunoprecipitates was decreased with a similar time course. Furthermore, both herbimycin A and genistein, potent inhibitors of tyrosine kinase activity, inhibited HCRI-induced inhibition of PI-3 kinase activity as well as HCRI-induced apoptotic cell death. Once the catalytic subunit p110 becomes tyrosine-phosphorylated, the regulatory subunit p85 appears to be dissociated from the catalytic subunit, because we observed a decreasing amount of p85 regulatory subunits in p110 immunoprecipitates in response to HCRI treatment. These results strongly suggest the novel function of tyrosine phosphorylation of catalytic subunit p110 of PI-3 kinase in the regulation of its kinase activity. The tyrosine phosphorylation of these catalytic subunits may play an important role in the intracellular signal transduction of apoptotic cell death. To our knowledge, this is the first report that tyrosine phosphorylation of p110 catalytic subunit acts as a negative regulator of its kinase activity.


Assuntos
Inibidores de Hidroximetilglutaril-CoA Redutases/farmacologia , Músculos/citologia , Fosfatidilinositol 3-Quinases/metabolismo , Animais , Benzoquinonas , Domínio Catalítico , Linhagem Celular , Inibidores Enzimáticos/farmacologia , Genisteína/farmacologia , Lactamas Macrocíclicas , Músculos/efeitos dos fármacos , Músculos/enzimologia , Fosfatidilinositol 3-Quinases/química , Inibidores de Fosfoinositídeo-3 Quinase , Fosforilação , Fosfotirosina/metabolismo , Testes de Precipitina , Proteínas Tirosina Quinases/antagonistas & inibidores , Quinonas/farmacologia , Ratos , Rifabutina/análogos & derivados , Sinvastatina/farmacologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA