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1.
Support Care Cancer ; 29(2): 917-923, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32533437

RESUMO

Homcology is a project that represents both an opportunity for patients who may benefit from chemotherapy so far, but present physical and social problems that prevent day-hospital access, and a model of "no-profit" contribution to the Public Health System. Our medical oncology department conducted the project from May 2014 to January 2019. We included frail patients (G-8 < 14), with advanced disease, treated with oral, subcutaneous, or parenteral biological agents, with limitations to day-hospital access, comorbidities, and at least 6-month life expectancy. A multidisciplinary team included three oncologists, four nurses, an anesthetist, a psychologist, and a physiotherapist. Satisfaction was evaluated with FAMCARE scale. A total of 188 patients (median age of 73 years, 38-87) were enrolled. Ninety percent of patients presented with metastatic disease and a median G-8 score of 8.8 (3-13.5). All of them received anticancer treatment and concomitant supportive care; 24 patients received two or more lines of treatment. The median duration of taking care was 175 days (7-1200). A median number of 254 (195-325) nursing and 164 (139-190) medical visits were performed a year, with an average of 1.9 and 1.2 visits a month per patient respectively. The median number of in-line patients was 20 (17-25). Hospitalization occurred in 18% of cases. One-third of them died at home. The others were referred to hospice. Our experience shows that the integration of home cancer treatment and supportive care is effective. Hospitalization rate is lower than data reported in the literature. Results need to be confirmed in prospective pharmacoeconomics studies.


Assuntos
Serviços de Assistência Domiciliar , Neoplasias/tratamento farmacológico , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Idoso Fragilizado , Cuidados Paliativos na Terminalidade da Vida , Humanos , Expectativa de Vida , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos
2.
Ann Oncol ; 20(6): 1086-93, 2009 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19193705

RESUMO

BACKGROUND: Treatment aimed at eradicating Helicobacter pylori infection results in lymphoma remission in most localized gastric mucosa-associated lymphoid tissue (MALT) lymphomas. The aim of this survey is to investigate the long-term effect of this therapeutic approach in a large series of patients. METHODS: One hundred and five patients with localized gastric MALT lymphoma were initially treated only with H. pylori eradication regimens. Lymphoma responses were graded using the Wotherspoon score. RESULTS: Helicobacter pylori, detected by histology in 81% of cases, was eradicated in all positive patients. Histological regression of the lymphoma was achieved in 78 of 102 assessable patients [76%, 95% confidence interval (CI): 67% to 84%] with complete remission (score 0-2) in 66 and partial remission (score 3) in 12. At a median follow-up time of 6.3 years, histological remission was consistently confirmed in 33 of 74 assessable patients, while 25 had score fluctuations (from 0 to 4) and 13 presented a lymphoma relapse (score 5). Only one patient had a distant progression. Transformation to a large-cell lymphoma was seen in two cases. The 5- and 10-year overall survival is 92% (95% CI: 84% to 96%) and 83% (95% CI: 70% to 91%), respectively. Only one patient died of lymphoma after transformation to a high-grade lymphoma. CONCLUSIONS: Helicobacter pylori eradication resulted in complete lymphoma remission in the majority of cases. Long-term clinical disease control was achieved in most patients. A watch and wait policy appears to be safe in patients with minimal residual disease or histological-only local relapse.


Assuntos
Infecções por Helicobacter/tratamento farmacológico , Helicobacter pylori , Linfoma de Zona Marginal Tipo Células B/tratamento farmacológico , Neoplasias Gástricas/tratamento farmacológico , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Linfoma de Zona Marginal Tipo Células B/microbiologia , Masculino , Pessoa de Meia-Idade , Indução de Remissão , Estudos Retrospectivos , Neoplasias Gástricas/microbiologia , Adulto Jovem
3.
Radiol Med ; 113(1): 87-100, 2008 Feb.
Artigo em Inglês, Italiano | MEDLINE | ID: mdl-18338130

RESUMO

PURPOSE: This study was done to assess the effectiveness and advantages of computed tomography (CT) fluoroscopy as a guide for locating and treating lesions that are not amenable to ultrasound (US) guidance, and to evaluate the CT signs of immediate technical success and the short-term results. MATERIALS AND METHODS: Over the past year, we selected 14 patients (four women and ten men; mean age 73, range 61-83 years) out of 103 candidates for hepatic radiofrequency ablation (RFA). The 14 lesions comprised seven residual tumours after combined embolisation and US-guided RFA of a large hepatocellular carcinoma (HCC), which were indistinguishable from necrosis or surrounding healthy parenchyma; two HCC nodules in locations that were inaccessible by US; five metastases (two from renal carcinoma, two from colorectal adenocarcinoma and one from lung carcinoma), of which one could not be distinguished from the surrounding healthy parenchyma on US and four were inaccessible by US. Lesion diameters were between 1.4 and 3.5 cm. The procedures were performed in the CT room with anaesthesiological assistance using a coaxial LeVeen needle electrode (14 gauge, 2-to 4-cm array diameter). Immediate technical success was evaluated by multidetector CT (MDCT), and follow-up was carried out with MDCT at 3 and 6 months and yearly thereafter. RESULTS: Immediate technical success was obtained in 13/14 patients; one case required further placement of the electrode due to incomplete ablation of a hypervascular lesion. In 2/3 metastatic lesions with portal vein supply, there were no recurrences at 3 and 6 months; in 1/3, we observed disease progression, with the appearance of additional nodules at 6 months. The two metastases with arterial supply showed no signs of recurrence at 3 months; one case developed a recurrence along the ablation margin, with the appearance of satellite nodules at 6 months. In two HCC nodules, there was immediate technical success and no recurrence at 3 and 6 months. Of the seven residual tumours of HCC, all treated with immediate technical success, we observed disease progression, with the appearance of satellite nodules at 3 months in one case, at 6 months in another and at 12 months in another; 3/7 patients were free of disease at 12-month follow-up; 1/7 died 5 months later due to causes unrelated to the procedure. CONCLUSIONS: CT fluoroscopy is overcoming the limitations of CT in locating and treating lesions with different hepatic vascularisation and those unamenable to US; furthermore, it reduces the length of the procedure, thanks to the faster and more accurate placement of the needle electrode. MDCT proved to be a reliable method in the assessment of immediate and short-term results of RFA.


Assuntos
Ablação por Cateter/métodos , Fluoroscopia/métodos , Hepatectomia/métodos , Neoplasias Hepáticas/cirurgia , Radiografia Intervencionista/métodos , Tomografia Computadorizada por Raios X/métodos , Adenocarcinoma/secundário , Adenocarcinoma/cirurgia , Idoso , Idoso de 80 Anos ou mais , Carcinoma/secundário , Carcinoma/cirurgia , Carcinoma Hepatocelular/cirurgia , Carcinoma Hepatocelular/terapia , Carcinoma de Células Renais/secundário , Carcinoma de Células Renais/cirurgia , Neoplasias do Colo/patologia , Progressão da Doença , Intervalo Livre de Doença , Embolização Terapêutica , Feminino , Seguimentos , Humanos , Processamento de Imagem Assistida por Computador/métodos , Neoplasias Renais/patologia , Neoplasias Hepáticas/secundário , Neoplasias Hepáticas/terapia , Neoplasias Pulmonares/patologia , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/patologia , Taxa de Sobrevida , Resultado do Tratamento
4.
Oncogene ; 25(30): 4165-71, 2006 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-16501606

RESUMO

Claspin is a Chk1-interacting protein that participates in the DNA replication checkpoint. Expression of Claspin fluctuates in a cell cycle-dependent manner, but the mechanisms involved in the regulation of Claspin protein levels have not been explored. In this study, we show that Claspin expression is downregulated by the proteasome-mediated degradation pathway and that Chk1 is required to maintain Claspin stability. Downregulation of Chk1 expression by siRNA or inhibition of Chk1 activity by UCN01 decreases Claspin levels in cells. Conversely, overexpression of Chk1 increases Claspin levels. These data indicate a role of Chk1 in regulating Claspin stability in the cell. Since Claspin has also been shown to participate in Chk1 activation following DNA damage, we further explored the exact role of Claspin during Chk1 activation following replication stress. We observed that while Rad17 is required for early Chk1 activation after hydroxyurea treatment, Claspin is only required to sustain Chk1 activation. Based on these findings, we propose that Claspin functions at late stages of Chk1 activation following DNA damage. Once Chk1 is activated, it stabilizes Claspin, which in turn helps to maintain Chk1 activation during replication stress. In summary, these data indicate that the interaction between Claspin and Chk1 is complex. These proteins regulate each other and thus ensure the proper cell cycle progression and replication checkpoint control.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Proteínas Quinases/fisiologia , Ciclo Celular/fisiologia , Linhagem Celular Tumoral , Quinase 1 do Ponto de Checagem , Células HeLa , Humanos , Complexo de Endopeptidases do Proteassoma/fisiologia , Transdução de Sinais/fisiologia
6.
Curr Protoc Cytom ; Chapter 9: Unit 9.16, 2001 May.
Artigo em Inglês | MEDLINE | ID: mdl-18770753

RESUMO

Understanding of transmembrane signaling during NK-cell activation has greatly expanded during the past few years. The discovery and characterization of novel triggering and inhibitory receptors have revealed the complexity of these processes. This unit focuses on receptor-initiated signaling pathways that modulate NK functions. Establishing the roles of different signaling pathways in NK cells is a crucial step in the design of therapeutic approaches for selective enhancement or suppression of NK-cell activation.


Assuntos
Separação Celular/métodos , Citometria de Fluxo/métodos , Células Matadoras Naturais/metabolismo , Transdução de Sinais , Animais , Membrana Celular/metabolismo , Humanos , Modelos Biológicos , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Tirosina Quinases/metabolismo
7.
Curr Protoc Immunol ; Chapter 11: Unit 11.9B, 2001 May.
Artigo em Inglês | MEDLINE | ID: mdl-18432709

RESUMO

Natural killer (NK) cells are a subpopulation of lymphocytes that can mediate cytotoxicity of certain tumor cells, virus-infected cells, and normal cells. In addition to their cytotoxic potential, NK cells secrete a variety of cytokines and chemokines that can modulate the function, growth, and differentiation of other immune cells. These different responses are initiated by the interaction of specific NK surface receptors with defined soluble or cell-associated ligands. There are several different types of receptors on the NK cell surface including "triggering" receptors, adhesion molecules, cytokine receptors, and MHC-recognizing killer-cell inhibitory receptors. The functional response of an NK cell is the result of the integration of signals transduced by these different types of receptors. Some of these signaling pathways are similar to other lymphoid cells, but there are also unique features employed by NK cells. This overview focuses on receptor-initiated signaling pathways that modulate NK functions.


Assuntos
Células Matadoras Naturais/imunologia , Receptores Imunológicos/fisiologia , Transdução de Sinais/imunologia , Animais , Antígenos de Histocompatibilidade Classe I/fisiologia , Humanos , Receptores KIR/fisiologia
8.
Eur J Immunol ; 30(10): 2791-8, 2000 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11069059

RESUMO

The mitogen-activated protein kinase (MAPK) p38 modulates a variety of cellular functions, including proliferation, differentiation and cell death. However, we report here a novel function for p38, i.e. the regulation of cytotoxic lymphocyte-mediated cytotoxicity. Stimulation of NK cells by either cross-linking of their FcgammaRIII receptors or by binding to NK-sensitive target cells induces the phosphorylation and activation of p38, and also of its upstream regulators MKK3/MKK6. Pharmacologic analyses suggest that Src-family and Syk-family protein tyrosine kinases couple the NK cell surface receptors to p38 activation. The role of p38 in the cytotoxic function of NK cells was tested by treatment of NK cells with the cell-permeable, p38-specific inhibitor SB203580. Interestingly, exposure to the drug reduced both antibody-dependent cellular cytotoxicity and natural cytotoxicity, but maximal inhibitory concentrations resulted in only partial inhibition. Collectively, these results suggest that the p38 MAPK pathway is stimulated during the development of NK cell-mediated cytotoxicity and that efficient killing is influenced by both p38-dependent and p38-independent pathways. More broadly, this study identifies the regulation of cell-mediated killing as a novel role for p38 in cytotoxic lymphocytes.


Assuntos
Citotoxicidade Imunológica/fisiologia , Células Matadoras Naturais/enzimologia , Ativação Linfocitária , Sistema de Sinalização das MAP Quinases , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Androstadienos/farmacologia , Citotoxicidade Celular Dependente de Anticorpos/fisiologia , Inibidores Enzimáticos/farmacologia , Precursores Enzimáticos/fisiologia , Flavonoides/farmacologia , Humanos , Imidazóis/farmacologia , Indóis/farmacologia , Peptídeos e Proteínas de Sinalização Intracelular , Células Matadoras Naturais/imunologia , Maleimidas/farmacologia , Proteínas Quinases Ativadas por Mitógeno/antagonistas & inibidores , Inibidores de Fosfoinositídeo-3 Quinase , Fosforilação , Proteína Quinase C/antagonistas & inibidores , Processamento de Proteína Pós-Traducional , Proteínas Tirosina Quinases/fisiologia , Piridinas/farmacologia , Receptores de IgG/imunologia , Quinase Syk , Wortmanina , Proteínas Quinases p38 Ativadas por Mitógeno , Quinases da Família src/fisiologia
10.
EMBO J ; 18(7): 1832-44, 1999 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-10202147

RESUMO

Accumulating evidence indicates that the interdomain B regions of ZAP-70 and Syk play pivotal roles in the coupling of T-cell antigen receptor (TCR) stimulation to the activation of downstream signaling pathways. The interdomain B region of ZAP-70 contains at least three candidate sites of tyrosine phosphorylation. In this report, we identify Tyr319 as a functionally important phosphorylation site in the ZAP-70 interdomain B region. TCR crosslinkage triggered a rapid increase in the phosphorylation of Tyr319 in Jurkat T cells. Although mutation of Tyr319 to Phe had no effect on the tyrosine kinase activity of ZAP-70, the resulting ZAP(Y319-->F) mutant failed to reconstitute TCR-dependent Ca2+ mobilization, Ras activation, CD69 expression and NFAT-dependent transcription in ZAP-70-deficient Jurkat cells. These defects were correlated with reduced tyrosine phosphorylation of phospholipase C (PLC)-gamma1 and the LAT adapter protein in the ZAP(Y319-->F)-expressing cells. On the other hand, ZAP(Y319-->F)-expressing cells displayed normal increases in SLP-76 phosphorylation and ERK activation during TCR stimulation. Phosphorylation of Tyr319 promoted the association of ZAP-70 with the SH2 domains of two key signaling molecules, Lck and PLC-gamma1. These studies suggest that Tyr319 phosphorylation is required for the assembly of a ZAP-70-containing signaling complex that leads to the activation of the PLC-gamma1- and Ras-dependent signaling cascades in antigen-stimulated T cells.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal , Isoenzimas/metabolismo , Proteínas de Membrana , Proteínas Quinases Ativadas por Mitógeno , Proteínas Nucleares , Proteínas Tirosina Quinases/metabolismo , Receptores de Antígenos de Linfócitos T/metabolismo , Fosfolipases Tipo C/metabolismo , Proteínas ras/metabolismo , Animais , Sequência de Bases , Sítios de Ligação , Cálcio/metabolismo , Proteínas Quinases Dependentes de Cálcio-Calmodulina/metabolismo , Proteínas de Transporte/metabolismo , Domínio Catalítico/genética , Linhagem Celular , Primers do DNA/genética , Proteínas de Ligação a DNA/metabolismo , Ativação Enzimática , Humanos , Isoenzimas/química , Proteína Tirosina Quinase p56(lck) Linfócito-Específica/química , Proteína Tirosina Quinase p56(lck) Linfócito-Específica/metabolismo , Proteína Quinase 1 Ativada por Mitógeno , Proteína Quinase 3 Ativada por Mitógeno , Modelos Biológicos , Fatores de Transcrição NFATC , Fosfolipase C gama , Fosfoproteínas/metabolismo , Mutação Puntual , Proteínas Tirosina Quinases/química , Proteínas Tirosina Quinases/genética , Fatores de Transcrição/metabolismo , Fosfolipases Tipo C/química , Proteína-Tirosina Quinase ZAP-70 , Domínios de Homologia de src
11.
Kidney Int ; 52(4): 917-25, 1997 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-9328930

RESUMO

Activation of cAMP signaling pathway was shown to inhibit some pathobiologic processes in mesangial cells (MC). We investigated whether adrenomedullin (ADM), a potent agonist of adenylate cyclase, is synthesized in MC and whether it can, via cAMP, suppress the generation of reactive oxygen metabolites (ROM) and proliferation of cells in glomeruli. With the use of an immunohistologic technique ADM was detected in mesangial and microvascular areas of rat glomeruli. MC grown in primary culture synthesized ADM, and the synthesis was stimulated by TNF alpha and IL-1 beta but not by PDGF and EGF. ADM inhibited ROM generation in MC dose-dependently and caused in situ activation of protein kinase A (PKA). In macrophages (cell line J774) ROM generation was about four times higher than in MC and was inhibited by ADM in a similar way as in MC. The rate of MC proliferation, measured by [3H]-incorporation, and the activity of mitogen-activated protein kinase (MAPK) stimulated by PDGF and EGF were dose-dependently inhibited by ADM; the maximum inhibition (at 10 nM ADM) was about -80%. Mitogenesis of MC and MAPK activity when stimulated to a similar extent by endothelin (ET-1) was inhibited by ADM to a significantly (P < 0.01) lesser degree (-30%). Further, ADM inhibited PDF-stimulated mitogenesis and activation of MAPK in cultured vascular smooth muscle cells (VSMC). The inhibition of PDGF-activated MAPK by ADM in VSMC was reversed by the protein kinase A (PKA) inhibitor, H89. Taken together, results indicate the adrenomedullin (ADM) generated in mesangial cells (MC) can suppress, via activation of the cAMP-protein kinase A (PKA) signaling pathway, reactive oxygen metabolites (ROM) generation in MC and infiltrating macrophages as well as mitogen-activated protein kinase (MAPK)-mediated mitogenesis in MC and vascular smooth muscle cells (VSMC). We suggest that introglomerular ADM may serve as a cytoprotective autoacoid that suppresses pathobiologic processes evoked by immuno-inflammatory injury of glomeruli.


Assuntos
AMP Cíclico/fisiologia , Glomérulos Renais/patologia , Glomérulos Renais/fisiopatologia , Peptídeos/fisiologia , Transdução de Sinais/fisiologia , Vasodilatadores/metabolismo , Adrenomedulina , Animais , Proteínas Quinases Dependentes de Cálcio-Calmodulina/antagonistas & inibidores , Proteínas Quinases Dependentes de Cálcio-Calmodulina/metabolismo , Linhagem Celular , Células Cultivadas , Inibidores Enzimáticos/farmacologia , Mesângio Glomerular/metabolismo , Imuno-Histoquímica , Glomérulos Renais/metabolismo , Macrófagos/citologia , Macrófagos/metabolismo , Masculino , Mitose/efeitos dos fármacos , Músculo Liso Vascular/citologia , Músculo Liso Vascular/enzimologia , Peptídeos/metabolismo , Peptídeos/farmacologia , Ratos , Ratos Sprague-Dawley , Espécies Reativas de Oxigênio/metabolismo
12.
Kidney Int ; 51(5): 1500-6, 1997 May.
Artigo em Inglês | MEDLINE | ID: mdl-9150465

RESUMO

Recent discovery of cyclic ADP-ribose (cADPR) as an agent that triggers Ca2+ release from intracellular stores, through ryanodine receptor channel, is an important new development in the investigation of intracellular signaling mechanisms. We determined the capacity of kidney and its components for synthesis of cADPR from beta-NAD, that is catalyzed by enzyme ADP-ribosyl cyclase, and enzymatic inactivation that is catalyzed by cADPR-glycohydrolase. Little or no activity of ADP-ribosyl cyclase was found in extracts from the whole rat kidney, renal cortex, outer and inner medulla. On the other hand, incubation of beta-NAD with similar extracts from rat liver, spleen, heart, and brain resulted in biosynthesis of cADPR. In addition, extracts from suspension of proximal tubules or microdissected proximal convoluted tubules virtually lacked ADP-ribosyl cyclase activity. In sharp contrast to proximal tubules and cortex, extracts from glomeruli had high ADP-ribosyl cyclase activity, similar to that found in non-renal tissues. Authenticity of cADPR biosynthesized in glomeruli was documented by several criteria such as HPLC analysis, effect of inhibitors and homologous desensitization of Ca(2+)-release bioassay. On the other hand, the activity of cADPR-glycohydrolase was similar in extracts from glomeruli and in extracts from kidney cortex. Mesangial cells and vascular smooth muscle cells grown in primary culture displayed considerable ADPR-ribose cyclase activity. Our results show that extracts from glomeruli, unlike extracts from renal tissue zones and proximal tubules, have a singularly high capacity for synthesis of cADPR. We surmise that cADPR-triggered Ca(2+)-releasing system can serve as an intracellular signaling pathway that may be operant in regulations of glomerular cell functions.


Assuntos
Adenosina Difosfato Ribose/análogos & derivados , Glomérulos Renais/metabolismo , Adenosina Difosfato Ribose/metabolismo , Animais , Cálcio/metabolismo , ADP-Ribose Cíclica , Rim/metabolismo , Masculino , Ratos , Ratos Sprague-Dawley
13.
J Biol Chem ; 272(15): 9854-9, 1997 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-9092521

RESUMO

Some major pathobiologic processes in renal mesangial cells, elicited in response to immunoinflammatory stimuli, are modulated via cAMP-protein kinase A (PKA) signaling pathways; namely, generation of reactive oxygen metabolites (ROM) and accelerated proliferation of mesangial cells. We investigated the role of cAMP phosphodiesterase (PDE) isozymes in these regulatory mechanisms. Generation of ROM in cultured rat mesangial cells was inhibited by selective inhibitors of PDE4, rolipram and denbufylline, whereas PDE3 inhibitors, cilostamide and lixazinone, had no effect. Conversely, cilostamide or lixazinone suppressed mitogenic synthesis of DNA in mesangial cells, but 1 microM rolipram or 1 microM denbufylline showed no inhibitory effect. The efficacy of PDE isozyme inhibitors (IC50) to suppress [3H]thymidine incorporation or ROM generation paralleled IC50 values for inhibition of cAMP PDE. Incubation of mesangial cells with either rolipram alone or with cilostamide alone increased significantly in situ activity of PKA in mesangial cells, assessed by (-cAMP/+cAMP) PKA activity ratio, and the stimulatory effects were additive. Results indicate that in mesangial cells a cAMP pool that is metabolized by PDE4 activates PKA and thereby inhibits ROM generation; another cAMP pool that is metabolized by PDE3 activates another PKA (isozyme or pool) which suppresses proliferation of mesangial cells. We propose that in mesangial cells, a cAMP-PKA pathway that regulates mitogenesis is determined by activity of PDE3, whereas another cAMP-PKA pathway is directed by activity of PDE4 and controls ROM generation. Therefore, two PDE isozymes within one cell type compartmentalize distinct cAMP signaling pathways.


Assuntos
3',5'-AMP Cíclico Fosfodiesterases/metabolismo , AMP Cíclico/fisiologia , Mesângio Glomerular/citologia , Diester Fosfórico Hidrolases/metabolismo , Transdução de Sinais/fisiologia , Superóxidos/metabolismo , Animais , Bucladesina/farmacologia , Compartimento Celular , AMP Cíclico/metabolismo , Nucleotídeo Cíclico Fosfodiesterase do Tipo 3 , Nucleotídeo Cíclico Fosfodiesterase do Tipo 4 , Cinética , Mitose , NADPH Oxidases/metabolismo , Inibidores de Fosfodiesterase/administração & dosagem , Inibidores de Fosfodiesterase/farmacologia , Pirrolidinonas/administração & dosagem , Pirrolidinonas/farmacologia , Quinolonas/farmacologia , Ratos , Rolipram , Xantinas/farmacologia
14.
Am J Physiol ; 272(2 Pt 1): C416-20, 1997 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-9124283

RESUMO

The molecular mechanism that initiates Ca2+ signaling in sea urchin egg fertilization has not yet been clarified. To determine whether sea urchin sperm may generate and possibly supply cyclic ADP-ribose (cADPR) as a Ca2+-releasing factor in the course of sea urchin egg fertilization, we determined cADPR content and the capacity for cADPR synthesis in sea urchin sperm. cADPR content was determined using the sea urchin egg homogenate Ca2+-release bioassay combined with high-performance liquid chromatography (HPLC). We found that sperm homogenates synthesized cADPR from beta-NAD but did not synthesize cADPR when alpha-NAD was the substrate. The identity of cADPR generated by sperm homogenates was verified by HPLC analysis, use of specific Ca2+-release antagonists, and homologous desensitization of the sea urchin egg homogenate Ca2+-release bioassay. The ambient content of cADPR was approximately 0.3 nmol cADPR/g wet wt sea urchin sperm. Our results show that sperm can synthesize cADPR and that they contain cADPR levels comparable to other tissues.


Assuntos
Adenosina Difosfato Ribose/análogos & derivados , Transdução de Sinais , Espermatozoides/metabolismo , Adenosina Difosfato Ribose/fisiologia , Animais , Bioensaio , Cromatografia Líquida de Alta Pressão , ADP-Ribose Cíclica , Feminino , Masculino , Ouriços-do-Mar/fisiologia
15.
Int Arch Occup Environ Health ; 70(3): 161-72, 1997.
Artigo em Inglês | MEDLINE | ID: mdl-9298398

RESUMO

OBJECT: Diesel soot has been recognized as probably carcinogenic to humans. Elemental carbon (also called black carbon) in soot is considered at the moment as the most significant surrogate to be measured for assessing the exposure to this pollutant. Its analysis is done by combustion in an oven and determination of the CO2 formed, after elimination of the organic fraction of the soot by heating and/or by solvent extraction. The analysis allows determination of both fractions of the soot: "elemental carbon" (EC) and organic carbon (OC). The sum of EC and OC is called TC (total carbon). METHOD: An informal European coordination group organized two round robin tests on filter samples collected from diluted diesel emissions. The first round (RRT1) was performed on 13 different samples analyzed by ten laboratories. The range of loading was 2.5 to 150 micrograms/cm2 of EC. No evaluation of the precision within laboratories could be made since each laboratory gave only one result per sample. Therefore a second round (RRT2) was organized with two samples and a blank filter sent in several portions to 11 laboratories. It should be stressed that each laboratory used its own method and that no standardization was planned at this stage. RESULTS: Results of RRT1 showed that the coefficient of variation between laboratories decreased with higher loading and was around 10% to 15% for EC above about 20 micrograms/cm2. Dispersion of the results varied and it appeared that the way OC is removed from the soot is probably the most important factor of influence. The correlation between the laboratories was good as a whole but some systematic differences could be detected. Besides the different techniques to remove the organic carbon, the pretreatment of the filter by HCl (either as a vapor or as a solution) to remove the inorganic carbonates (potential interference sources), is probably also a significant factor of influence in the dispersion of the results between laboratories. It is not yet clear from these results whether the "environmental" laboratories give different results from the "occupational" laboratories, but it is clear that their objectives differ since for the "environmentalists", EC is not a specific marker of diesel emmissions, in contrast to the "occupationalists". CONCLUSION: It can be concluded that, although significant differences exist between laboratories they can be attributed mainly to the narrow distribution of the results within a single laboratory, and that the overall agreement of the results for EC and TC is fairly good. These results obtained with pure diesel engine emissions, should be complemented by field samples, but they have already achieved relevant findings in the performance of the procedures used to assess exposure to diesel soot.


Assuntos
Poluentes Atmosféricos/análise , Carbono/análise , Gasolina
16.
Am J Physiol ; 269(4 Pt 1): C1042-7, 1995 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-7485444

RESUMO

Cyclic ADP-ribose (cADPR) is a potent mediator of Ca2+ mobilization from intracellular stores in sea urchin eggs. However, the regulation of the cADPR-induced Ca2+ release system is not yet fully elucidated. We now report that spermine and related polyamines, in physiological concentrations, were able to inhibit the Ca2+ release induced by cADPR in sea urchin egg homogenate bioassays, as measured using the Ca2+ indicator fluo 3, but had no effect on the Ca2+ release induced by D-myo-inositol 1,4,5-trisphosphate (IP3) or by nicotinate adenine dinucleotide phosphate (NAADP). Spermine was a more potent inhibitor of the cADPR-induced Ca2+ release than spermidine and putrescine. Spermine inhibited not only the release induced by cADPR but also the Ca2+ release induced by caffeine and ryanodine. Finally, pretreatment of the sea urchin egg homogenates with caffeine or Sr2+ and Ca2+ prevented the inhibitory effect of spermine on cADPR-induced Ca2+ release. We propose that polyamines, which are present in millimolar concentrations in fertilized eggs, are specific inhibitors of the ryanodine channel and perhaps may serve as endogenous regulators of the cADPR-induced Ca2+ release system.


Assuntos
Adenosina Difosfato Ribose/análogos & derivados , Cálcio/metabolismo , Poliaminas/farmacologia , Adenosina Difosfato Ribose/farmacologia , Animais , Cafeína/farmacologia , ADP-Ribose Cíclica , Inositol 1,4,5-Trifosfato/farmacologia , NADP/análogos & derivados , NADP/farmacologia , Óvulo/metabolismo , Rianodina/farmacologia , Ouriços-do-Mar/metabolismo , Espermina/farmacologia
17.
J Clin Invest ; 96(1): 401-10, 1995 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-7615811

RESUMO

We studied interactions between the mitogen-activated protein kinase (MAPK) signalling pathway and cAMP-protein kinase (PKA) signaling pathway in regulation of mitogenesis of mesangial cells (MC) determined by [3H]thymidine incorporation, with or without added EGF. Forskolin or dibutyryl cAMP strongly (by 60-70%) inhibited [3H]thymidine incorporation into MC. Cilostamide, lixazinone or cilostazol selective inhibitors of cAMP-phosphodiesterase (PDE) isozyme PDE-III, inhibited mitogenesis to similar extent as forskolin and DBcAMP and activated in situ PKA, but without detectable increase in cAMP levels. Cilostamide and cilostazol were more than three times more effective at inhibiting mesangial mitogenesis than rolipram and denbufylline, inhibitors of isozyme PDE-IV, even though PDE-IV was two times more abundant in MC than was PDE-III. On the other hand, when incubated with forskolin, rolipram-enhanced cAMP accumulation was far greater (10-100x) than with cilostamide. EGF increased MAPK activity (+300%); PDE isozyme inhibitors which suppressed mitogenesis also inhibited MAPK. PDE isozyme inhibitors also suppressed PDGF-stimulated MC proliferation. We conclude that cAMP inhibits the mitogen-dependent MAPK-signaling pathway probably by decreasing the activity of Raf-1 due to PKA-catalyzed phosphorylation. Further, we surmise that minor increase in the cAMP pool metabolized by PDE-III is intimately related to regulation of mesangial proliferation. Thus, PDE isozyme inhibitors have the potential to suppress MC proliferation by a focused effect upon signaling pathways.


Assuntos
3',5'-AMP Cíclico Fosfodiesterases/antagonistas & inibidores , Proteínas Quinases Dependentes de AMP Cíclico/fisiologia , Mesângio Glomerular/efeitos dos fármacos , Isoenzimas/antagonistas & inibidores , Animais , Proteínas Quinases Dependentes de Cálcio-Calmodulina/metabolismo , Células Cultivadas , Fator de Crescimento Epidérmico/farmacologia , Mesângio Glomerular/citologia , Mesângio Glomerular/enzimologia , Masculino , Fator de Crescimento Derivado de Plaquetas/farmacologia , Pirrolidinonas/farmacologia , Quinolonas/farmacologia , Ratos , Ratos Sprague-Dawley , Rolipram , Timidina/metabolismo
18.
Kidney Int ; 46(1): 28-36, 1994 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-7933846

RESUMO

Several independent studies indicate that synthetic inhibitors of cyclic-3',5'-nucleotide phosphodiesterase (PDE) isozymes, especially inhibitors of PDE-IV, are potent agents which suppress generation of reactive oxygen metabolites (ROM) by NADPH oxidase in leukocytes. Recent studies also show that NADPH oxidase is present in all cell types populating glomeruli. In view of this, we investigated PDE isozymes and their relation to ROM in isolated rat glomeruli. Glomeruli have the capacity to hydrolyze cAMP by isozymes PDE-II, PDE-III and PDE-IV, whereas cGMP is hydrolyzed by PDE-I and PDE-V. Inhibitor of PDE-IV rolipram inhibited significantly (cca 40 to 50%) ROM generation in response to stimulation by phorbol myristate acetate (PMA). Inhibitor of PDE-III cilostamide had only minor suppressive effects and inhibitors of other PDE isozymes did not influence ROM generation. Rolipram (3 microM) suppressed ROM generation without detectable increase in cAMP content. Incubation of glomeruli with forskolin, which increased cAMP content in glomeruli tenfold, inhibited ROM generation to a similar degree as rolipram. The suppression of ROM generation by rolipram was prevented by Rp-cAMPS, a specific inhibitor of protein kinase A (PKA) activity. Further, incubation of glomeruli with rolipram elicited marked in situ activation of PKA (+ 100%), as documented by increase in the (-cAMP/+cAMP) PKA activity ratio. We suggest that selective inhibitor of PDE-IV rolipram acted via the cAMP-signaling pathway and suppressed ROM generation possibly via phosphorylating ras-type GTP-binding protein component of NADPH oxidase and thereby blocking assembly of functional NADPH oxidase complex.(ABSTRACT TRUNCATED AT 250 WORDS)


Assuntos
3',5'-AMP Cíclico Fosfodiesterases/antagonistas & inibidores , Isoenzimas/antagonistas & inibidores , Glomérulos Renais/enzimologia , Inibidores de Fosfodiesterase/farmacologia , Espécies Reativas de Oxigênio/metabolismo , 3',5'-AMP Cíclico Fosfodiesterases/metabolismo , Animais , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Isoenzimas/metabolismo , Glomérulos Renais/efeitos dos fármacos , Medições Luminescentes , Masculino , Ratos , Ratos Sprague-Dawley
19.
Planta Med ; 58(5): 476, 1992 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-17226509
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