RESUMO
The hypoperfusion intensity ratio (HIR) is associated with collateral status and reflects the impaired microperfusion of brain tissue in patients with acute ischemic stroke and large vessel occlusion (AIS-LVO). As a deterioration in cerebral blood flow is associated with brain edema, we aimed to investigate whether HIR is correlated with the early edema progression rate (EPR) determined by the ischemic net water uptake (NWU) in a multicenter retrospective analysis of AIS-LVO patients anticipated for thrombectomy treatment. HIR was automatically calculated as the ratio of time-to-maximum (TMax) > 10 s/(TMax) > 6 s. HIRs < 0.4 were regarded as favorable (HIR+) and ≥0.4 as unfavorable (HIR−). Quantitative ischemic lesion NWU was delineated on baseline NCCT images and EPR was calculated as the ratio of NWU/time from symptom onset to imaging. Multivariable regression analysis was used to assess the association of HIR with EPR. This study included 731 patients. HIR+ patients exhibited a reduced median NWU upon admission CT (4% (IQR: 2.1−7.6) versus 8.2% (6−10.4); p < 0.001) and less median EPR (0.016%/h (IQR: 0.007−0.04) versus 0.044%/h (IQR: 0.021−0.089; p < 0.001) compared to HIR− patients. Multivariable regression showed that HIR+ (ß: 0.53, SE: 0.02; p = 0.003) and presentation of the National Institutes of Health Stroke Scale (ß: 0.2, SE: 0.0006; p = 0.001) were independently associated with EPR. In conclusion, favorable HIR was associated with lower early edema progression and decreased ischemic edema formation on baseline NCCT.
RESUMO
Zosterin, an apiose-rich pectic polysaccharide, was extracted and purified from the sea grass Zostera marina. Structural studies conducted by gas chromatography and NMR spectroscopy on a purified zosterin fraction (AGU) revealed a typical apiogalacturonan structure comprising an alpha-1,4-d-galactopyranosyluronan backbone substituted by 1,2-linked apiofuranose oligosaccharides and single apiose residues. The average molecular mass of AGU was estimated to be about 4100 Da with a low polydispersity. AGU inhibited proliferation of A431 human epidermoid carcinoma cells with an approximate IC(50) value of 3 microg/mL (0.7 microM). In addition, AGU inhibited A431 cell migration and invasion. Preliminary experiments showed that inhibition of metalloproteases expression could play a role in these antimigration and anti-invasive properties. Autohydrolysis of AGU, which eliminated apiose and oligo-apiose substituents, led to a virtual disappearance of cytotoxic properties, thus suggesting a direct structure-function relationship with the apiose-rich hairy region of AGU.
Assuntos
Antineoplásicos Fitogênicos/isolamento & purificação , Antineoplásicos Fitogênicos/farmacologia , Pectinas/isolamento & purificação , Pectinas/farmacologia , Polissacarídeos/química , Zosteraceae/química , Antineoplásicos Fitogênicos/química , Parede Celular/química , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Concentração Inibidora 50 , Biologia Marinha , Estrutura Molecular , Monossacarídeos/análise , Ressonância Magnética Nuclear Biomolecular , Pectinas/química , Pentoses/análise , Relação Estrutura-AtividadeRESUMO
In addition to their physiologic effects in inflammation and angiogenesis, chemokines are involved in cancer pathology. The aim of this study was to determine whether the chemokine stromal cell-derived factor 1 (SDF-1) induces the growth, migration, and invasion of human hepatoma cells. We show that SDF-1 G protein-coupled receptor, chemokine (C-X-C motif) receptor 4 (CXCR4), and SDF-1 mRNA are expressed in human hepatoma Huh7 cells, which secrete and bind SDF-1. This binding depends on CXCR4 and glycosaminoglycans. SDF-1 associates with CXCR4, and syndecan-4 (SDC-4), a heparan sulfate proteoglycan at the plasma membrane of Huh7 cells, induces the growth of Huh7 cells by promoting their entry into the cell cycle, and inhibits the tumor necrosis factor-alpha-mediated apoptosis of the cells. SDF-1 also reorganizes Huh7 cytoskeleton and induces tyrosine phosphorylation of focal adhesion kinase. Finally, SDF-1 activates matrix metalloproteinase-9, resulting in increased migration and invasion of Huh7 cells. These biological effects of SDF-1 were strongly inhibited by the CXCR4 antagonist AMD3100, by a glycosaminoglycan, heparin, as well as by beta-D-xyloside treatment of the cells, or by c-jun NH(2)-terminal kinase/stress-activated protein kinase inhibitor. Therefore, the CXCR4, glycosaminoglycans, and the mitogen-activated protein kinase signaling pathways are involved in these events. The fact that reducing SDC-4 expression by RNA interference decreased SDF-1-induced Huh7 hepatoma cell migration and invasion strongly indicates that SDC-4 may be an auxiliary receptor for SDF-1. Finally, the fact that CXCR4 is expressed in hepatocellular carcinoma cells from liver biopsies indicates that the in vitro results reported here could be extended to in vivo conditions.
Assuntos
Carcinoma Hepatocelular/patologia , Movimento Celular , Proliferação de Células , Quimiocinas CXC/fisiologia , Neoplasias Hepáticas/patologia , Carcinoma Hepatocelular/metabolismo , Quimiocina CXCL12 , Citometria de Fluxo , Imunofluorescência , Glicosaminoglicanos/farmacologia , Humanos , Neoplasias Hepáticas/metabolismo , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Invasividade Neoplásica , Neovascularização Patológica , Fosforilação , Interferência de RNA , RNA Mensageiro/antagonistas & inibidores , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Receptores CXCR4/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Células Estromais/metabolismo , Células Estromais/patologia , Sindecana-1/metabolismo , Sindecana-2/metabolismo , Sindecana-4/antagonistas & inibidores , Sindecana-4/genética , Sindecana-4/metabolismo , Tirosina/metabolismoRESUMO
BACKGROUND: Sodium phenylacetate (NaPa) inhibits breast cancer cell proliferation decreasing prenylation of small G proteins including Ras. MATERIALS AND METHODS: Aponecrosis induced by NaPa in MCF-7 and MCF-7ras breast cancer cells was evaluated by measuring Annexin V/PI labelling by flow cytometry. Specific inhibitors of p42/44 (PD 98059), p38 (SB 600125) and JNK (SP 202190) in association with NaPa were also tested. Mitogen-activated kinase (MAPK) activation was measured by immunoprecipitation. RESULTS: NaPa induced cell death more efficiently (80%) in the MCF-7ras cells compared to the MCF-7 cells (60%). NaPa activated ERK 1/2 and its combination with PD 98059 decreased cell death in the MCF-7ras cells in contrast to the MCF-7 cells. Combination of NaPa with specific inhibitors of both JNK and p38 kinases also partly decreased MCF-7ras cell death. CONCLUSION: NaPa induced cell death differently when ras was overexpressed in breast cancer cells, partly involving p42/44, JNK and p38 pathways.
Assuntos
Genes ras , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Proteína Quinase 3 Ativada por Mitógeno/metabolismo , Fenilacetatos/farmacologia , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo , Animais , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Flavonoides/farmacologia , Camundongos , Proteínas Proto-Oncogênicas p21(ras)/metabolismoRESUMO
Xylans were purified from delignified holocellulose alkaline extracts of Castanea sativa (Spanish chestnut) and Argania spinosa (Argan tree) and their structures analyzed by means of GC of their per-trimethylsilylated methylglycoside derivatives and (1)H NMR spectroscopy. The structures deduced were characteristic of a 4-O-methylglucuronoxylan (MGX) and a homoxylan (HX), respectively, with degrees of polymerization ranging from 182 to 360. In the case of MGX, the regular or random distribution of 4-O-methylglucuronic acid along the xylosyl backbone--determined by MALDI mass spectrometry after autohydrolysis of the polysaccharide--varied and depended both on the botanical source from which they were extracted and on the xylan extraction procedure. The MGX also inhibited in different ways the proliferation as well as the migration and invasion capability of A431 human epidermoid carcinoma cells. These biological properties could be correlated with structural features including values of the degree of polymerization, 4-O-MeGlcA to xylose ratios, and distribution of 4-O-MeGlcA along the xylosyl backbone, giving evidence of a defined structure-activity relationship.
Assuntos
Antineoplásicos Fitogênicos/química , Antineoplásicos Fitogênicos/farmacologia , Fagaceae/química , Xilanos/química , Xilanos/farmacologia , Linhagem Celular Tumoral , Cromatografia Gasosa , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Relação Estrutura-AtividadeRESUMO
The synthesis and biological activity of chloroethyl pyrimidine nucleosides is presented. One of these new nucleosides analogues significantly inhibited cell proliferation, migration and invasion as tested in vitro on the A431 vulvar epidermal carcinoma cell line.
Assuntos
Antineoplásicos/síntese química , Hidrocarbonetos Clorados/síntese química , Nucleosídeos de Pirimidina/síntese química , Antineoplásicos/química , Antineoplásicos/farmacologia , Carcinoma de Células Escamosas/tratamento farmacológico , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Feminino , Humanos , Hidrocarbonetos Clorados/química , Hidrocarbonetos Clorados/farmacologia , Nucleosídeos de Pirimidina/química , Nucleosídeos de Pirimidina/farmacologia , Neoplasias Vulvares/tratamento farmacológicoRESUMO
The synthesis and biological activity of a novel DNA cross-linking antitumor agent is presented. The new alkylating agent significantly inhibited cell proliferation, migration and invasion as tested in vitro on the A431 vulvar epidermal carcinoma cell line.
Assuntos
Compostos de Mostarda Nitrogenada/síntese química , Compostos de Mostarda Nitrogenada/farmacologia , Timina/análogos & derivados , Antineoplásicos Alquilantes/síntese química , Antineoplásicos Alquilantes/química , Antineoplásicos Alquilantes/farmacologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Quimiotaxia/efeitos dos fármacos , Humanos , Metaloproteinase 2 da Matriz , Inibidores de Metaloproteinases de Matriz , Invasividade Neoplásica/prevenção & controle , Compostos de Mostarda Nitrogenada/química , Timina/química , Timina/farmacologiaRESUMO
The CC-chemokine regulated on activation, normal T-cell expressed, and presumably secreted (RANTES)/CCL5 mediates its biological activities through activation of G protein-coupled receptors, CCR1, CCR3, or CCR5, and binds to glycosaminoglycans. This study was undertaken to investigate whether this chemokine is involved in hepatoma cell migration or invasion and to modulate these effects in vitro by the use of glycosaminoglycan mimetics. We show that the human hepatoma Huh7 and Hep3B cells express RANTES/CCL5 G protein-coupled receptor CCR1 but not CCR3 nor CCR5. RANTES/CCL5 binding to these cells depends on CCR1 and glycosaminoglycans. Moreover, RANTES/CCL5 strongly stimulates the migration and the invasion of Huh7 cells and to a lesser extent that of Hep3B cells. RANTES/CCL5 also stimulates the tyrosine phosphorylation of focal adhesion kinase and activates matrix metalloproteinase-9 in Huh7 hepatoma cells, resulting in increased invasion of these cells. The fact that RANTES/CCL5-induced migration and invasion of Huh7 cells are both strongly inhibited by anti-CCR1 antibodies and heparin, as well as by beta-d-xyloside treatment of the cells, suggests that CCR1 and glycosaminoglycans are involved in these events. We then show by surface plasmon resonance that synthetic glycosaminoglycan mimetics, OTR4120 or OTR4131, directly bind to RANTES/CCL5. The preincubation of the chemokine with each of these mimetics strongly inhibited RANTES-induced migration and invasion of Huh7 cells. Therefore, targeting the RANTES-glycosaminoglycan interaction could be a new therapeutic approach for human hepatocellular carcinoma.
Assuntos
Materiais Biomiméticos/farmacologia , Carcinoma Hepatocelular/patologia , Movimento Celular/efeitos dos fármacos , Quimiocina CCL5/antagonistas & inibidores , Quimiocina CCL5/farmacologia , Glicosaminoglicanos/farmacologia , Neoplasias Hepáticas/patologia , Materiais Biomiméticos/síntese química , Linhagem Celular Tumoral , Quimiotaxia/efeitos dos fármacos , Glicosaminoglicanos/química , Humanos , Invasividade Neoplásica/patologiaRESUMO
INTRODUCTION: Investigation of the role of vascular endothelial growth factor-C (VEGF-C) and VEGF receptor-3 (VEGFR-3) in non-small-cell lung cancer (NSCLC) has mainly focused on lymph node (LN) metastasis related to lymphangiogenesis. However, the coexpression of VEGF-C/VEGFR-3 by tumour cells can independently play an important role. The present study was therefore designed to evaluate VEGF-C/VEGFR-3 coexpression in tumour cells from the primary tumour and corresponding LN metastases. METHODS: VEGF-C and VEGFR-3 expression in cancer cells were evaluated by immunohistochemistry in 92 NSCLC samples and 45 metastatic LNs. Ki67 expression and mitotic index (MI) in tumours and clinicopathological data were analysed concurrently. RESULTS: VEGFR-3 and VEGF-C expression were observed in 42% and 74% of tumours, respectively. Concurrent expression of VEGF-C and VEGFR-3, observed in 39% of tumours, was significantly associated with a higher proliferation rate and a higher incidence of LN metastases. VEGF-C expression in tumour cells was observed in 100% of metastatic LN and VEGF-C/VEGFR-3 coexpression was observed in 71% of metastatic LN. Finally, concurrent expression of VEGF-C/VEGFR-3 in the primary tumour was associated with poor disease-free survival on univariate analysis. CONCLUSION: In NSCLC cancer cells, VEGF-C/VEGFR-3 coexpression suggests an autocrine/paracrine loop responsible for a high proliferation rate in tumour cells. As VEGF-C/VEGFR-3 coexpression is very frequent in metastatic LN tumour cells, it can be hypothesised that this coexpression participates in the growth of LN metastasis.
Assuntos
Carcinoma Pulmonar de Células não Pequenas/metabolismo , Carcinoma Pulmonar de Células não Pequenas/patologia , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patologia , Linfonodos/patologia , Fator C de Crescimento do Endotélio Vascular/metabolismo , Receptor 3 de Fatores de Crescimento do Endotélio Vascular/metabolismo , Adulto , Idoso , Linhagem Celular Tumoral , Proliferação de Células , Sobrevivência Celular , Intervalo Livre de Doença , Feminino , Humanos , Metástase Linfática , Masculino , Pessoa de Meia-Idade , Modelos de Riscos ProporcionaisRESUMO
The integration of an electrocardiogram (ECG) device into a chip is already well known in the field of implanted devices, such as pacemakers. For noninvasive electrocardiology, this approach has not been used on a broad scale commercially. The extension of electrocardiology to telemetry, home care, and special applications as in magnetic resonance imaging has spawned a new interest in highly miniaturized ECG devices. In our company, we are aiming for using highly integrated devices exactly in these fields. On one hand, the home monitoring market ("eHealth," "pHealth") requires small and lightweight devices ("ECG in an electrode"); on the other hand, the use of an ECG device within a hostile environment as in an magnetic resonance imaging machine with strong electromagnetic fields requires small dimensions of the device. Of these 2 fields, the one of home monitoring is the most promising. There is a large population in need of such monitoring (eg, patients with congestive heart failure), and the cost issue in medical care drives the market in this direction. Projects in both fields will be presented as well as the first experiences as a middle-sized manufacturer in trying to produce an integrated ECG "device."
Assuntos
Diagnóstico por Computador/instrumentação , Eletrocardiografia Ambulatorial/instrumentação , Telemetria/instrumentação , Biotecnologia/instrumentação , Biotecnologia/tendências , Diagnóstico por Computador/métodos , Eletrocardiografia Ambulatorial/métodos , Desenho de Equipamento , Análise de Falha de Equipamento , Humanos , Indústrias/tendências , Miniaturização , Telemetria/métodosRESUMO
We previously reported a simple and efficient one-pot procedure for synthesis of 1-hydroxymethylene-1,1-bisphosphonic acids (HMBP). According to this method, we synthesized a series of new aromatic HMBP and investigated structure-activity relationships by evaluating their anti-proliferative activity against A431 human tumor cell line. Our results showed that the introduction of an extra methylene group in a pyridyl-containing R2 side chain increased 100-fold the anti-proliferative activity of the HMBP. In contrast, this chemical modification did not modify the anti-proliferative activity of compounds substituted with a phenyl-containing R2 side chain. Para-substitution of the phenyl ring with various groups markedly influenced the HMBP activity, the order of potency (bromine > chlorine > fluorine = none) closely matching the atomic volume of the substituted group. Moreover, changes in the substitution position of the bromine group also affected the anti-proliferative activity, the more potent activity being obtained with para-substitution of the phenyl ring. In conclusion, this structure-activity study led us to identify the new aromatic HMBP [(4-Bromo-phenyl)-hydroxy-phosphono-methyl]-phosphonic acid as a potent in vitro anti-proliferative molecule against tumor cell lines (IC50 value of 9.5 x 10(-5) M). Interestingly, this compound can be further easily esterified on its phosphonic acid functions according to our chemical method and, thus, represents a potential candidate for the development of new esterified HMBP with enhanced pharmacokinetics.
Assuntos
Antineoplásicos/química , Antineoplásicos/farmacologia , Difosfonatos/química , Difosfonatos/farmacologia , Ácido Etidrônico/análogos & derivados , Antineoplásicos/síntese química , Carcinoma de Células Escamosas/tratamento farmacológico , Carcinoma de Células Escamosas/patologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Difosfonatos/síntese química , Ensaios de Seleção de Medicamentos Antitumorais , Ácido Etidrônico/síntese química , Ácido Etidrônico/química , Ácido Etidrônico/farmacologia , Humanos , Ácido Risedrônico , Relação Estrutura-AtividadeRESUMO
There is increasing evidence that bisphosphonates have direct antitumor effects in vivo in addition to their therapeutic antiresorptive properties. Bisphosphonates inhibit proliferation and induce apoptosis of many cancer cell lines. They also exhibit anti-invasive properties in vitro and in vivo. We have previously shown that a novel non-nitrogen-containing bisphosphonate inhibited tumor growth of A431 human epidermoid carcinoma cells. In the present study, we investigated the antitumor properties of three nitrogen-containing bisphosphonates on A431 cells in vitro. We first compared the antiproliferative effects of pamidronate, alendronate and neridronate. Then, by matrigel invasion assay, the effect of alendronate on A431 cell invasiveness was studied. All three bisphosphonates were found to inhibit cell proliferation dose- and time-dependently. The most potent molecule was alendronate. The invasion test demonstrated that alendronate also inhibited cell invasion in a Boyden chamber. These data suggest that alendronate may have beneficial effects in the treatment of carcinomas exhibiting important angiogenesis.
Assuntos
Alendronato/farmacologia , Carcinoma de Células Escamosas/tratamento farmacológico , Neoplasias Vulvares/tratamento farmacológico , Carcinoma de Células Escamosas/patologia , Adesão Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Difosfonatos/farmacologia , Relação Dose-Resposta a Droga , Feminino , Inibidores do Crescimento/farmacologia , Humanos , Invasividade Neoplásica , Pamidronato , Neoplasias Vulvares/patologiaRESUMO
1. Since the sodium phenylacetate (NaPa) was reported to enhance the inhibitory effect of carboxymethyl benzylamide dextran (CMDB) on the breast cancer growth, we performed the esterification of CMDB with NaPa to obtain a new drug carrying the characteristics of these two components. A new molecule, phenylacetate carboxymethyl benzylamide dextran, was named NaPaC. 2. We investigated in vitro and in vivo the effects of NaPaC on MCF-7ras cell growth as well as its apoptotic and antiangiogenic effects in comparison to NaPa and CMDB. In addition, we assessed in vitro the antiproliferative effects of these drugs on other breast cancer cells, including MDA-MB-231, MDA-MB-435 and MCF-7. 3. In vitro, NaPaC inhibited MCF-7ras cell proliferation by 40% at concentration lower than that of CMDB and NaPa (12 microM vs 73 microM and 10 mM). IC(50)s were 6 and 28 microM for NaPaC and CMDB, respectively. The similar results were obtained for three other breast cancer cell lines. NaPaC reduced the DNA replication and induced cell recruitment in G(0)/G(1) phase more efficiently than its components. Moreover, it induced a cell death at concentration 1000-fold lower than NaPa. 4. In vivo, CMDB (150 mg kg(-1)) and NaPa (40 mg kg(-1)) inhibited the MCF-7ras tumour growth by 37 and 57%, respectively, whereas NaPaC (15 mg kg(-1)) decreased tumour growth by 66% without toxicity. 5. NaPa or CMDB reduced the microvessel number in tumour by 50% after 7 weeks of treatment. NaPaC had the same effect after only 2 weeks. After 7 weeks, it generated a large necrosis area without detectable microvessels. In vitro, NaPaC inhibited human endothelial cell proliferation more efficiently than CMDB or NaPa. NaPaC interacts with vascular endothelial growth factor as observed by affinity electrophoresis. 6. NaPaC acts like NaPa and CMDB but in more potent manner than components used separately. Its antiproliferative, aponecrotic and anti-angiogenic actions make it a good candidate for a new anti-cancer drug.
Assuntos
Inibidores da Angiogênese/farmacologia , Antineoplásicos/farmacologia , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/patologia , Dextranos/farmacologia , Inibidores do Crescimento/farmacologia , Células Tumorais Cultivadas/efeitos dos fármacos , Células Tumorais Cultivadas/patologia , Células 3T3 , Inibidores da Angiogênese/uso terapêutico , Animais , Antineoplásicos/uso terapêutico , Meios de Cultivo Condicionados/farmacologia , Dextranos/química , Dextranos/uso terapêutico , Relação Dose-Resposta a Droga , Endotélio Vascular/citologia , Endotélio Vascular/efeitos dos fármacos , Endotélio Vascular/fisiologia , Feminino , Inibidores do Crescimento/uso terapêutico , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Necrose , Fenilacetatos/farmacologia , Fenilacetatos/uso terapêutico , Ensaios Antitumorais Modelo de Xenoenxerto/estatística & dados numéricosRESUMO
ECGs are currently acquired during magnetic resonance examinations. This "hostile" environment highly distorts ECG signals, due to the high-static magnetic field, RF pulses and fast switching magnetic gradients. Specific signal processing is then required since the ECG signal is used for image synchronization with heart activity (or triggering) and for patient monitoring. A new set of two magnetic field gradient (MFG) artifact reduction methods, based on ECG and MFG artifact modelings and Bayesian filtering, is herein presented and will be called Bayesian gradient artifact reduction monitoring (BAGARRE-M) and BAGARRE-triggering. These algorithms overcome the limitations of state-of-the-art methods and enable accurate processing of very noisy ECG acquisitions during MRI. Whether for triggering or monitoring purposes, the presented methods overcome state-of-the-art techniques with both better QRS detection accuracy and signal denoising quality.
Assuntos
Artefatos , Eletrocardiografia/métodos , Imageamento por Ressonância Magnética/métodos , Dinâmica não Linear , Processamento de Sinais Assistido por Computador , Adulto , Algoritmos , Teorema de Bayes , Bases de Dados Factuais , Campos Eletromagnéticos , Feminino , Humanos , Masculino , Reprodutibilidade dos TestesRESUMO
Electrocardiogram (ECG) is required during magnetic resonance (MR) examination for monitoring patients under anaesthesia or with heart diseases and for synchronizing image acquisition with heart activity (triggering). Accurate and fast QRS detection is therefore desirable, but this task is complicated by artefacts related to the complex MR environment (high magnetic field, radio-frequency pulses and fast switching magnetic gradients). Specific signal processing has been proposed, whether using specific MR QRS detectors or ECG denoising methods. Most state-of-the-art techniques use a connection to the MR system for achieving their task, which is a major drawback since access to the MR system is often restricted. This paper introduces a new method for on-line ECG signal enhancement, called ICARE, which takes advantage of using multi-lead ECG and does not require any connection to the MR system. It is based on independent component analysis (ICA) and applied in real time. This algorithm yields accurate QRS detection for efficient triggering.
Assuntos
Algoritmos , Artefatos , Técnicas de Imagem de Sincronização Cardíaca/métodos , Eletrocardiografia/métodos , Imageamento por Ressonância Magnética/métodos , Processamento de Sinais Assistido por Computador , Adulto , Bases de Dados como Assunto , Reações Falso-Positivas , Feminino , Humanos , Masculino , Sensibilidade e Especificidade , Fatores de TempoRESUMO
A glucuronoxylan was purified from a delignified holocellulose alkaline extract of Castanea sativa (Spanish chestnut) and its structure analyzed by means of FT-IR, GC of the per-trimethylsilylated methylglycoside derivatives, and 1H and 13C NMR spectroscopy. The results supported a structure based on a linear polymer of xylopyranose units linked with beta(1-->4) bonds in which, on average, one out of every six units is substituted at C-2 by a 4-O-methylglucuronic acid unit; this structure is typical of a hardwood acidic 4-O-methylglucuronoxylan (MGX) with an estimated degree of polymerization of 200. The MGX from C. sativa inhibited the proliferation of A431 human epidermoid carcinoma cells with an IC50 value of 50 microM. In addition, this xylan inhibited A431 cell migration and invasion. Preliminary experiments showing that secretion of metalloproteinases MMP2 and MMP9 by A431 tumor cells was inhibited by the purified C. sativa MGX strongly suggest that this mechanism of action may play a role in its antimigration and anti-invasive properties.
Assuntos
Antineoplásicos Fitogênicos/isolamento & purificação , Antineoplásicos Fitogênicos/farmacologia , Fagaceae/química , Plantas Medicinais/química , Xilanos/isolamento & purificação , Xilanos/farmacologia , Antineoplásicos Fitogênicos/química , Ensaios de Seleção de Medicamentos Antitumorais , França , Humanos , Concentração Inibidora 50 , Estrutura Molecular , Xilanos/químicaRESUMO
The capsular polysaccharide produced by the thermophilic blue green alga/cyanobacterium Mastigocladus laminosus was tested for its cytotoxic activity against the A431 human epidermoid carcinoma cell line. This polysaccharide inhibited the proliferation of A431 cells in a dose-dependent manner with an IC (50) value of 50 microg mL (-1). In addition, this polysaccharide strongly inhibited A431 cell migration and invasion. Preliminary experiments showing that secretion of metalloproteinases MMP2 and MMP9 by A431 tumour cells was inhibited by this polysaccharide suggest that this mechanism of action could play a role in its anti-migration and anti-invasive properties. Acid hydrolysis of the polysaccharide produced specific oligosaccharides which conserved - at similar concentrations - their cytotoxic, anti-migration and anti-invasion properties; in this case, the mechanism of action was nevertheless uncorrelated to the decrease of metalloproteinase expression.
Assuntos
Antineoplásicos Fitogênicos/farmacologia , Cianobactérias , Fitoterapia , Polissacarídeos/farmacologia , Antineoplásicos Fitogênicos/administração & dosagem , Antineoplásicos Fitogênicos/uso terapêutico , Linhagem Celular Tumoral/efeitos dos fármacos , Linhagem Celular Tumoral/metabolismo , Movimento Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Humanos , Concentração Inibidora 50 , Metaloproteinase 2 da Matriz/metabolismo , Metaloproteinase 9 da Matriz/metabolismo , Polissacarídeos/administração & dosagem , Polissacarídeos/uso terapêuticoRESUMO
Bisphosphonates are extensively used in the treatment of patients with metastasis-induced osteolysis. The major drawback in the efficacy of all bisphosphonates lies in their high hydrophilic nature, which results in poor membrane permeability and low availability for soft tissues. A reasonable approach to overcome these problems consists in masking one or more ionizable groups of bisphosphonates, notably by esterification of the hydroxyl functions. We have previously shown that the novel non-nitrogen-containing bisphosphonate BP7033 inhibited angiogenesis and growth of primary tumors in nude mice. The present study focuses on the dimethyl-esterified analog of this compound (Me-BP7033). In-vitro, Me-BP7033 inhibited proliferation of human carcinoma A431 cells as well as their invasive activity based on a transwell invasion assay. in-vivo, administration of Me-BP7033 (0.3 mg/kg) twice a week for 5 weeks inhibited the tumor growth of A431 cells xenografted in nude mice by 65%. Immunostaining of endothelial cells (ECs) in tumor sections revealed that Me-BP7033 inhibited the intratumor ECs density by 60%. The in-vivo anti-angiogenic properties of Me-BP7033 were also demonstrated in an in-vivo angiogenesis assay showing that Me-BP7033 reduced the vascular endothelial growth factor-stimulated infiltration of ECs in a Matrigel plug by 70%. In summary, we demonstrated for the first time that a diesterified bisphosphonate exhibited in vivo both anti-tumoral and anti-angiogenic activities with no apparent sign of toxic effects. These new diesterified compounds, which could display enhanced bioavailability and pharmacokinetics, thus represent interesting candidates for therapeutic applications such as cancer treatment.
Assuntos
Álcoois Benzílicos/farmacologia , Carcinoma de Células Escamosas/tratamento farmacológico , Difosfonatos/farmacologia , Neovascularização Patológica/tratamento farmacológico , Animais , Álcoois Benzílicos/química , Carcinoma de Células Escamosas/irrigação sanguínea , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Difosfonatos/química , Humanos , Camundongos , Camundongos Nus , Transplante de Neoplasias , Fator A de Crescimento do Endotélio Vascular/farmacologiaRESUMO
Bisphosphonates (BP) are powerful inhibitors of bone resorption and are widely used in the treatment of patients with metastasis-induced osteolysis. In the present study, we show that a novel non-nitrogen-containing BP (BP7033) that exhibits antitumor activity is a potent inhibitor of both in vivo and in vitro angiogenesis. When administered to mice, BP7033 inhibited tumoral angiogenesis (65% at 0.06mg/injection) as well as tumor growth (65% at 0.006mg/injection) in a tumor model of A431 cells xenografted in nude mice, with no sign of toxicity. Additionally, in vivo angiogenesis induced by vascular endothelial growth factor-containing Matrigel implants was reduced by 90% in the presence of BP7033 (0.6mg/plug). In vitro, BP7033 inhibited proliferation of human umbilical vein endothelial cells (HUVEC) (IC(50) value 3x10(-4) M) and completely prevented the formation of capillary-like tubules by HUVEC in Matrigel. Moreover, treatment of A431 cells by BP7033 induced an inhibition of Ras processing and a decrease in the secretion of both vascular endothelial growth factor and matrix metalloproteinase-2, two well-known stimulators of the proliferation and migration of endothelial cells. These findings indicate that this new BP compound has marked antiangiogenic properties and thus represents a promising candidate for treatment of malignant diseases with an angiogenic component.