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1.
Bioact Mater ; 38: 411-421, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38774458

RESUMO

Biodegradable metals offer a promising means to ameliorate many of the long-term risks associated with vascular devices made of conventional biostable stent metals. While numerous biodegradable metal alloys have been developed and characterized in animal models, knowledge of their blood reactivity and thrombogenicity remains unknown. Metal hemocompatibility is particularly valuable because current generation drug-eluting stents pose a significant long-term thrombosis risk. In this study, four pure metals, widely used as degradable base materials (Fe, Zn, Mg, and Mo), and three alloys commonly used in cardiovascular devices [NiTi, CoCr, and stainless steel (SS)] were evaluated. This work examined how each of these metals activate platelets, coagulation factors, and inflammation using in vitro hemocompatibility assays and a clinically relevant ex vivo non-human primate arteriovenous shunt model. Testing found that while all metals promoted a downstream activation of platelets and coagulation in flowing whole blood, platelet and fibrin attachment to Mg was markedly reduced. Additionally, Fe and Mo trended toward higher platelet attachment and contact pathway activation. Overall, the results suggest that Mg may delay clot initiation, but not eliminate clot formation, indicating the importance of understanding thrombosis in Mg alloys that are currently being developed for clinical use as biodegradable stents.

2.
Ann Oncol ; 34(10): 885-898, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37597578

RESUMO

BACKGROUND: HER2 mutations are targetable alterations in patients with hormone receptor-positive (HR+) metastatic breast cancer (MBC). In the SUMMIT basket study, patients with HER2-mutant MBC received neratinib monotherapy, neratinib + fulvestrant, or neratinib + fulvestrant + trastuzumab (N + F + T). We report results from 71 patients with HR+, HER2-mutant MBC, including 21 (seven in each arm) from a randomized substudy of fulvestrant versus fulvestrant + trastuzumab (F + T) versus N + F + T. PATIENTS AND METHODS: Patients with HR+ HER2-negative MBC with activating HER2 mutation(s) and prior cyclin-dependent kinase 4/6 inhibitor (CDK4/6i) therapy received N + F + T (oral neratinib 240 mg/day with loperamide prophylaxis, intramuscular fulvestrant 500 mg on days 1, 15, and 29 of cycle 1 then q4w, intravenous trastuzumab 8 mg/kg then 6 mg/kg q3w) or F + T or fulvestrant alone. Those whose disease progressed on F + T or fulvestrant could cross-over to N + F + T. Efficacy endpoints included investigator-assessed objective response rate (ORR), clinical benefit rate (RECIST v1.1), duration of response, and progression-free survival (PFS). Plasma and/or formalin-fixed paraffin-embedded tissue samples were collected at baseline; plasma was collected during and at end of treatment. Extracted DNA was analyzed by next-generation sequencing. RESULTS: ORR for 57 N + F + T-treated patients was 39% [95% confidence interval (CI) 26% to 52%); median PFS was 8.3 months (95% CI 6.0-15.1 months). No responses occurred in fulvestrant- or F + T-treated patients; responses in patients crossing over to N + F + T supported the requirement for neratinib in the triplet. Responses were observed in patients with ductal and lobular histology, 1 or ≥1 HER2 mutations, and co-occurring HER3 mutations. Longitudinal circulating tumor DNA sequencing revealed acquisition of additional HER2 alterations, and mutations in genes including PIK3CA, enabling further precision targeting and possible re-response. CONCLUSIONS: The benefit of N + F + T for HR+ HER2-mutant MBC after progression on CDK4/6is is clinically meaningful and, based on this study, N + F + T has been included in the National Comprehensive Cancer Network treatment guidelines. SUMMIT has improved our understanding of the translational implications of targeting HER2 mutations with neratinib-based therapy.


Assuntos
Neoplasias da Mama , Feminino , Humanos , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Fulvestranto , Receptor ErbB-2 , Trastuzumab
3.
Nat Commun ; 14(1): 3754, 2023 06 26.
Artigo em Inglês | MEDLINE | ID: mdl-37365181

RESUMO

Dopaminergic cell loss due to the accumulation of α-syn is a core feature of the pathogenesis of Parkinson disease. Neuroinflammation specifically induced by α-synuclein has been shown to exacerbate neurodegeneration, yet the role of central nervous system (CNS) resident macrophages in this process remains unclear. We found that a specific subset of CNS resident macrophages, border-associated macrophages (BAMs), play an essential role in mediating α-synuclein related neuroinflammation due to their unique role as the antigen presenting cells necessary to initiate a CD4 T cell response whereas the loss of MHCII antigen presentation on microglia had no effect on neuroinflammation. Furthermore, α-synuclein expression led to an expansion in border-associated macrophage numbers and a unique damage-associated activation state. Through a combinatorial approach of single-cell RNA sequencing and depletion experiments, we found that border-associated macrophages played an essential role in immune cell recruitment, infiltration, and antigen presentation. Furthermore, border-associated macrophages were identified in post-mortem PD brain in close proximity to T cells. These results point to a role for border-associated macrophages in mediating the pathogenesis of Parkinson disease through their role in the orchestration of the α-synuclein-mediated neuroinflammatory response.


Assuntos
Doença de Parkinson , Humanos , Doença de Parkinson/metabolismo , alfa-Sinucleína/metabolismo , Doenças Neuroinflamatórias , Macrófagos/metabolismo , Inflamação/patologia , Microglia/metabolismo
4.
Ann Oncol ; 34(2): 173-185, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-36414192

RESUMO

BACKGROUND: First-line nivolumab plus ipilimumab prolongs survival versus chemotherapy in advanced non-small-cell lung cancer (NSCLC). We further characterized clinical benefit with this regimen in a large pooled patient population and assessed the effect of response on survival. PATIENTS AND METHODS: Data were pooled from four studies of first-line nivolumab plus ipilimumab in advanced NSCLC (CheckMate 227 Part 1, 817 cohort A, 568 Part 1, and 012). Overall survival (OS), progression-free survival (PFS), objective response rate, duration of response, and safety were assessed. Landmark analyses of OS by response status at 6 months and by tumor burden reduction in responders to nivolumab plus ipilimumab were also assessed. RESULTS: In the pooled population (N = 1332) with a minimum follow-up of 29.1-58.9 months, median OS was 18.6 months, with a 3-year OS rate of 35%; median PFS was 5.4 months (3-year PFS rate, 17%). Objective response rate was 36%; median duration of response was 23.7 months, with 38% of responders having an ongoing response at 3 years. In patients with tumor programmed death-ligand 1 (PD-L1) <1%, ≥1%, 1%-49%, or ≥50%, 3-year OS rates were 30%, 38%, 30%, and 48%. Three-year OS rates were 30% and 38% in patients with squamous or non-squamous histology. Efficacy outcomes in patients aged ≥75 years were similar to the overall pooled population (median OS, 20.1 months; 3-year OS rate, 34%). In the pooled population, responders to nivolumab plus ipilimumab at 6 months had longer post-landmark OS than those with stable or progressive disease; 3-year OS rates were 66%, 22%, and 14%, respectively. Greater depth of response was associated with prolonged survival; in patients with tumor burden reduction ≥80%, 50% to <80%, or 30% to <50%, 3-year OS rates were 85%, 72%, and 44%, respectively. No new safety signals were identified in the pooled population. CONCLUSION: Long-term survival benefit and durable response with nivolumab plus ipilimumab in this large patient population further support this first-line treatment option for advanced NSCLC.


Assuntos
Carcinoma Pulmonar de Células não Pequenas , Neoplasias Pulmonares , Humanos , Nivolumabe/uso terapêutico , Carcinoma Pulmonar de Células não Pequenas/patologia , Ipilimumab/efeitos adversos , Neoplasias Pulmonares/patologia , Intervalo Livre de Progressão , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos
5.
ESMO Open ; 7(2): 100408, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35279527

RESUMO

BACKGROUND: In the phase III CASPIAN study, first-line durvalumab in combination with etoposide plus either cisplatin or carboplatin (EP) significantly improved overall survival (OS) versus EP alone in extensive-stage small-cell lung cancer (ES-SCLC). Durvalumab plus tremelimumab plus EP numerically improved OS versus EP, but did not reach statistical significance. Here we report updated OS in censored patients after median follow-up of >3 years. PATIENTS AND METHODS: 805 patients with treatment-naïve ES-SCLC were randomized 1 : 1 : 1 to durvalumab plus EP, durvalumab plus tremelimumab plus EP, or EP. The two primary endpoints were OS for durvalumab plus EP versus EP and for durvalumab plus tremelimumab plus EP versus EP. RESULTS: As of 22 March 2021 (median follow-up 39.4 months, 86% maturity), durvalumab plus EP continued to demonstrate improved OS versus EP: hazard ratio (HR) 0.71 [95% confidence interval (CI) 0.60-0.86; nominal P = 0.0003]; median OS was 12.9 versus 10.5 months, and 36-month OS rate was 17.6% versus 5.8%. Durvalumab plus tremelimumab plus EP continued to numerically improve OS versus EP: HR 0.81 (95% CI: 0.67-0.97; nominal P = 0.0200); median OS was 10.4 months, and 36-month OS rate was 15.3%. Twenty-seven and nineteen patients in the durvalumab plus EP and durvalumab plus tremelimumab plus EP arms, respectively, remained on durvalumab treatment at data cut-off. CONCLUSIONS: Three times more patients were estimated to be alive at 3 years when treated with durvalumab plus EP versus EP, with the majority still receiving durvalumab at data cut-off, further establishing durvalumab plus EP as first-line standard of care for ES-SCLC.


Assuntos
Neoplasias Pulmonares , Carcinoma de Pequenas Células do Pulmão , Anticorpos Monoclonais , Anticorpos Monoclonais Humanizados , Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Etoposídeo/uso terapêutico , Humanos , Neoplasias Pulmonares/tratamento farmacológico , Platina/uso terapêutico , Carcinoma de Pequenas Células do Pulmão/tratamento farmacológico
7.
Bone Marrow Transplant ; 55(7): 1290-1296, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32440014

RESUMO

ASTRACT: Granulocyte-Colony-Stimulating factor (G-CSF) is currently the standard mobilising agent for peripheral blood stem cell (PBSC) donation. Concerns that it may trigger chromosome aberrations similar to those observed in leukaemia patients were refuted but long-term effects of G-CSF mobilisation on genome integrity remains unclear. In the setting of a multi-centre clinical trial we screened blood samples from 50 PBSC donors at cellular and gene level for aberrations common in haematological malignancies using fluorescence in situ hybridisation (FISH) and next generation sequencing (NGS) assays. Analysis of samples collected before, on the day of donation, 90 and 180 days after G-CSF admission confirmed the absence of short-term effects in PBSC donors on both quiescent and dividing cells. This data did not differ from the results of 50 individuals tested 3-5 years after bone marrow donation and 50 healthy persons. NGS using a panel targeting 54 genes recurrently affected in myeloid disorders (TruSight Myeloid panel, Illumina) showed that the gene profiles of samples from 48 PBSC donors remained stable throughout the study period. These data strongly indicate absence of detrimental effects on the genome integrity caused by PBSC donation.


Assuntos
Células-Tronco de Sangue Periférico , Doadores não Relacionados , Medula Óssea , Fator Estimulador de Colônias de Granulócitos , Mobilização de Células-Tronco Hematopoéticas , Humanos , Coleta de Tecidos e Órgãos
8.
Alzheimers Dement ; 16(1): 60-70, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31914226

RESUMO

INTRODUCTION: Behavioral variant frontotemporal dementia (bvFTD) may present sporadically or due to an autosomal dominant mutation. Characterization of both forms will improve understanding of the generalizability of assessments and treatments. METHODS: A total of 135 sporadic (s-bvFTD; mean age 63.3 years; 34% female) and 99 familial (f-bvFTD; mean age 59.9; 48% female) bvFTD participants were identified. f-bvFTD cases included 43 with known or presumed chromosome 9 open reading frame 72 (C9orf72) gene expansions, 28 with known or presumed microtubule-associated protein tau (MAPT) mutations, 14 with known progranulin (GRN) mutations, and 14 with a strong family history of FTD but no identified mutation. RESULTS: Participants with f-bvFTD were younger and had earlier age at onset. s-bvFTD had higher total Neuropsychiatric Inventory Questionnaire (NPI-Q) scores due to more frequent endorsement of depression and irritability. DISCUSSION: f-bvFTD and s-bvFTD cases are clinically similar, suggesting the generalizability of novel biomarkers, therapies, and clinical tools developed in either form to the other.


Assuntos
Demência Frontotemporal , Predisposição Genética para Doença , Mutação/genética , Testes Neuropsicológicos/estatística & dados numéricos , Fatores Etários , Idoso , Encéfalo/patologia , Proteína C9orf72/genética , Feminino , Demência Frontotemporal/classificação , Demência Frontotemporal/genética , Humanos , Masculino , Pessoa de Meia-Idade , América do Norte , Progranulinas/genética , Proteínas tau/genética
10.
J Thorac Oncol ; 13(8): 1138-1145, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29874546

RESUMO

BACKGROUND: Despite the significant antitumor activity of pembrolizumab in NSCLC, clinical benefit has been less frequently observed in patients whose tumors harbor EGFR mutations compared to EGFR wild-type patients. Our single-center experience on the KEYNOTE-001 trial suggested that pembrolizumab-treated EGFR-mutant patients, who were tyrosine kinase inhibitor (TKI) naïve, had superior clinical outcomes to those previously treated with a TKI. As TKI naïve EGFR-mutants have generally been excluded from pembrolizumab studies, data to guide treatment decisions in this patient population is lacking, particularly in patients with programmed death ligand 1 (PD-L1) expression ≥50%. METHODS: We conducted a phase II trial (NCT02879994) of pembrolizumab in TKI naive patients with EGFR mutation-positive, advanced NSCLC and PD-L1-positive (≥1%, 22C3 antibody) tumors. Pembrolizumab was administered 200 mg every 3 weeks. The primary endpoint was objective response rate. Secondary endpoints included safety of pembrolizumab, additional pembrolizumab efficacy endpoints, and efficacy and safety of an EGFR TKI after pembrolizumab. RESULTS: Enrollment was ceased due to lack of efficacy after 11 of 25 planned patients were treated. Eighty-two percent of trial patients were treatment naïve, 64% had sensitizing EGFR mutations, and 73% had PD-L1 expression ≥50%. Only 1 patient had an objective response (9%), but repeat analysis of this patient's tumor definitively showed the original report of an EGFR mutation to be erroneous. Observed treatment-related adverse events were similar to prior experience with pembrolizumab, but two deaths within 6 months of enrollment, including one attributed to pneumonitis, were of concern. CONCLUSIONS: Pembrolizumab's lack of efficacy in TKI naïve, PD-L1+, EGFR-mutant patients with advanced NSCLC, including those with PD-L1 expression ≥50%, suggests that it is not an appropriate therapeutic choice in this setting.


Assuntos
Anticorpos Monoclonais Humanizados/uso terapêutico , Antígeno B7-H1/biossíntese , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Neoplasias Pulmonares/tratamento farmacológico , Adulto , Idoso , Carcinoma Pulmonar de Células não Pequenas/patologia , Receptores ErbB/genética , Feminino , Humanos , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patologia , Masculino , Pessoa de Meia-Idade , Mutação , Inibidores de Proteínas Quinases/uso terapêutico
11.
Ann Oncol ; 29(suppl_1): i38-i46, 2018 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-29462257

RESUMO

Molecular profiling has changed the treatment landscape in advanced non-small-cell lung cancer. Accurately identifying the tumours that harbour sensitizing EGFR mutations, the most common targetable molecular alteration, as well as those with acquired resistance mutations (e.g. T790M) on treatment is a high clinical priority. The current clinical gold standard is genotyping of tumour specimens. However, the practical utility of this approach is limited by the lack of available tissue and the potential complications associated with biopsies. With the advent of newer sequencing assays, it has become feasible to assess tumour genomics via a blood sample, termed a 'liquid biopsy'. In this review, we summarize the available techniques for liquid biopsies and their applicability for detecting sensitizing and resistance EGFR mutations and how these results may be used for making treatment decisions.


Assuntos
Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Técnicas de Genotipagem/métodos , Neoplasias Pulmonares/tratamento farmacológico , Inibidores de Proteínas Quinases/farmacologia , Biomarcadores Tumorais/sangue , Biomarcadores Tumorais/genética , Biomarcadores Tumorais/metabolismo , Carcinoma Pulmonar de Células não Pequenas/sangue , Carcinoma Pulmonar de Células não Pequenas/genética , Carcinoma Pulmonar de Células não Pequenas/patologia , DNA Tumoral Circulante/sangue , DNA Tumoral Circulante/genética , Tomada de Decisão Clínica , Resistencia a Medicamentos Antineoplásicos/genética , Receptores ErbB/antagonistas & inibidores , Receptores ErbB/genética , Estudos de Viabilidade , Humanos , Biópsia Líquida/métodos , Pulmão/patologia , Neoplasias Pulmonares/sangue , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patologia , Mutação , Valor Preditivo dos Testes , Prognóstico , Inibidores de Proteínas Quinases/uso terapêutico , Medição de Risco/métodos , Resultado do Tratamento
12.
Ann Oncol ; 29(3): 700-706, 2018 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-29216356

RESUMO

Background: A major limitation of circulating tumor DNA (ctDNA) for somatic mutation detection has been the low level of ctDNA found in a subset of cancer patients. We investigated whether using a combined isolation of exosomal RNA (exoRNA) and cell-free DNA (cfDNA) could improve blood-based liquid biopsy for EGFR mutation detection in non-small-cell lung cancer (NSCLC) patients. Patients and methods: Matched pretreatment tumor and plasma were collected from 84 patients enrolled in TIGER-X (NCT01526928), a phase 1/2 study of rociletinib in mutant EGFR NSCLC patients. The combined isolated exoRNA and cfDNA (exoNA) was analyzed blinded for mutations using a targeted next-generation sequencing panel (EXO1000) and compared with existing data from the same samples using analysis of ctDNA by BEAMing. Results: For exoNA, the sensitivity was 98% for detection of activating EGFR mutations and 90% for EGFR T790M. The corresponding sensitivities for ctDNA by BEAMing were 82% for activating mutations and 84% for T790M. In a subgroup of patients with intrathoracic metastatic disease (M0/M1a; n = 21), the sensitivity increased from 26% to 74% for activating mutations (P = 0.003) and from 19% to 31% for T790M (P = 0.5) when using exoNA for detection. Conclusions: Combining exoRNA and ctDNA increased the sensitivity for EGFR mutation detection in plasma, with the largest improvement seen in the subgroup of M0/M1a disease patients known to have low levels of ctDNA and poses challenges for mutation detection on ctDNA alone. Clinical Trials: NCT01526928.


Assuntos
Carcinoma Pulmonar de Células não Pequenas/sangue , DNA Tumoral Circulante/sangue , Análise Mutacional de DNA/métodos , Neoplasias Pulmonares/sangue , RNA/sangue , Acrilamidas/uso terapêutico , Adulto , Idoso , Antineoplásicos/uso terapêutico , Biomarcadores Tumorais/sangue , Biomarcadores Tumorais/genética , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Carcinoma Pulmonar de Células não Pequenas/genética , Receptores ErbB/genética , Exossomos , Feminino , Genes erbB-1 , Humanos , Biópsia Líquida/métodos , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/genética , Masculino , Pessoa de Meia-Idade , Pirimidinas/uso terapêutico , Sensibilidade e Especificidade
13.
Ann Oncol ; 28(4): 874-881, 2017 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-28168303

RESUMO

Background: Pembrolizumab improved survival as first- and second-line therapy compared with chemotherapy in patients with highly programmed death ligand 1 (PD-L1) expressing advanced non-small cell lung cancer (NSCLC). We report the long-term safety and clinical activity of pembrolizumab as first-line therapy for patients with advanced NSCLC and the correlation between PD-L1 expression and efficacy. Patients and methods: In the open-label phase 1b KEYNOTE-001 trial, treatment-naive patients with advanced NSCLC whose tumors expressed PD-L1 (≥1% staining, assessed using a prototype assay) were randomly assigned to intravenous pembrolizumab 2 or 10 mg/kg every 3 (Q3W) or 2 (Q2W) weeks. Response was assessed per central RECIST v1.1 every 9 weeks in all patients who received ≥1 pembrolizumab dose. Using pre-treatment tumor tissue, a clinical assay quantified the percentage of tumor cells expressing PD-L1 as tumor proportion score (TPS). Results: Between 1 March 2013 and 18 September 2015, 101 patients received pembrolizumab 2 mg/kg Q3W (n = 6), 10 mg/kg Q3W (n = 49), or 10 mg/kg Q2W (n = 46). Of these, 27 (26.7%) had TPS ≥50%, 52 (51.5%) had TPS 1%-49%, and 12 (11.9%) had TPS <1%. The objective response rate (ORR) was 27% (27/101, 95% CI 18-37) and median overall survival was 22.1 months (95% CI 17.1-27.2). In patients with PD-L1 TPS ≥50%, ORR, 12-month PFS, and 12-month OS were higher [14/27 (51.9%; 95% CI 32%-71%), 54%, and 85%, respectively] than the overall population [27/101 (26.7%; 95% CI 18.4%-36.5%), 35%, 71%]. Pembrolizumab was well tolerated, with only 12 (11.9%) patients experiencing grade 3/4 treatment-related adverse events and no treatment-related deaths. Conclusions: Pembrolizumab provides promising long-term OS benefit with a manageable safety profile for PD-L1-expressing treatment-naive advanced NSCLC, with greatest efficacy observed in patients with TPS ≥50%. Clinical trial name and number: KEYNOTE-001 (ClinicalTrials.gov, NCT01295827).


Assuntos
Anticorpos Monoclonais Humanizados/administração & dosagem , Antineoplásicos/administração & dosagem , Antígeno B7-H1/antagonistas & inibidores , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Neoplasias Pulmonares/tratamento farmacológico , Adulto , Idoso , Idoso de 80 Anos ou mais , Anticorpos Monoclonais Humanizados/efeitos adversos , Antineoplásicos/efeitos adversos , Carcinoma Pulmonar de Células não Pequenas/mortalidade , Intervalo Livre de Doença , Relação Dose-Resposta a Droga , Feminino , Humanos , Estimativa de Kaplan-Meier , Neoplasias Pulmonares/mortalidade , Masculino , Pessoa de Meia-Idade , Resultado do Tratamento
14.
Mater Sci Eng C Mater Biol Appl ; 61: 516-25, 2016 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-26838879

RESUMO

Magnesium alloys have been widely investigated for biodegradable medical applications. However, the shielding of harmful cells (eg. bacteria or tumorous cells) from immune surveillance may be compounded by the increased porosity of biodegradable materials. We previously demonstrated the improved corrosion resistance and mechanical properties of a novel EW62 (Mg-6%Nd-2%Y-0.5%Zr)) magnesium alloy by rapid solidification followed by extrusion (RS) compared to its conventional counterpart (CC). The present in vitro study evaluated the influence of rapid solidification on cytotoxicity to murine osteosarcoma cells. We found that CC and RS corrosion extracts significantly reduced cell viability over a 24-h exposure period. Cell density was reduced over 48 h following direct contact on both CC and RS surfaces, but was further reduced on the CC surface. The direct presence of cells accelerated corrosion for both materials. The corroded RS material exhibited superior mechanical properties relative to the CC material. The data show that the improved corrosion resistance of the rapidly solidified EW62 alloy (RS) resulted in a relatively reduced cytotoxic effect on tumorous cells. Hence, the tested alloy in the form of a rapidly solidified substance may introduce a good balance between its biodegradation characteristics and cytotoxic effect towards cancerous and normal cells.


Assuntos
Implantes Absorvíveis , Ligas , Neoplasias Ósseas/metabolismo , Magnésio , Osteossarcoma/metabolismo , Ligas/química , Ligas/farmacologia , Animais , Neoplasias Ósseas/patologia , Linhagem Celular Tumoral , Corrosão , Magnésio/química , Magnésio/farmacologia , Camundongos , Osteossarcoma/patologia , Porosidade
15.
Surg Neurol Int ; 6: 129, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26257987

RESUMO

BACKGROUND: Pineal region tumors are rare and diverse. Among them exist reports of pleomorphic xanthroastrocytoma (PXA) and pleomorphic granular cell astrocytoma (PGCA) of the pineal gland. These related tumors are remarkably similar sharing pleomorphic histologic features with only minor immunohistochemical and ultrastructural differences. CASE DESCRIPTION: We present a case of a 42-year old right-handed woman presented with a longstanding history of migraine headaches which had worsened over the two months leading up to her hospitalization. MRI revealed a 1.7 × 1.3 × 1.6 cm intensely enhancing lesion originating in the pineal gland. The tumor closely resembled PGCA but did not strictly fit the diagnostic requirements of either PGCA or PXA. CONCLUSION: The present case highlights the exotic nature of pineal region tumors with pleomorphic cell histology. Given the diverse range of tumors encountered in the pineal region, pathological confirmation is mandatory. Favorable clinical outcomes demonstrate that surgical resection alone can yield excellent long-term results for tumors falling within the spectrum of pleomorphic lesions of the pineal gland.

16.
Mater Sci Eng C Mater Biol Appl ; 51: 226-32, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25842129

RESUMO

The high corrosion rate of magnesium (Mg) and Mg-alloys precludes their widespread acceptance as implantable biomaterials. Here, we investigated the potential for rapid solidification (RS) to increase the stress corrosion cracking (SCC) resistance of a novel Mg alloy, Mg-6%Nd-2%Y-0.5%Zr (EW62), in comparison to its conventionally cast (CC) counterpart. RS ribbons were extrusion consolidated in order to generate bioimplant-relevant geometries for testing and practical use. Microstructural characteristics were examined by SEM. Corrosion rates were calculated based upon hydrogen evolution during immersion testing. The surface layer of the tested alloys was analyzed by X-ray photoelectron spectroscopy (XPS). Stress corrosion resistance was assessed by slow strain rate testing and fractography. The results indicate that the corrosion resistance of the RS alloy is significantly improved relative to the CC alloy due to a supersaturated Nd enrichment that increases the Nd2O3 content in the external oxide layer, as well as a more homogeneous structure and reduced grain size. These improvements contributed to the reduced formation of hydrogen gas and hydrogen embrittlement, which reduced the SCC sensitivity relative to the CC alloy. Therefore, EW62 in the form of a rapidly solidified extruded structure may serve as a biodegradable implant for biomedical applications.


Assuntos
Implantes Absorvíveis , Materiais Biocompatíveis/química , Líquidos Corporais/química , Magnésio/química , Ligas , Materiais Biomiméticos/química , Corrosão , Módulo de Elasticidade , Eletrólitos/química , Dureza , Hidrogênio/química , Teste de Materiais , Desenho de Prótese , Estresse Mecânico , Propriedades de Superfície , Resistência à Tração
17.
J Biomed Mater Res B Appl Biomater ; 103(8): 1541-8, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25491147

RESUMO

Magnesium (Mg) and Mg-alloys are being considered as implantable biometals. Despite their excellent biocompatibility and good mechanical properties, their rapid corrosion is a major impediment precluding their widespread acceptance as implantable biomaterials. Here, we investigate the potential for rapid solidification to increase the corrosion resistance of Mg alloys. To this end, the effect of rapid solidification on the environmental and stress corrosion behavior of the AZ80 Mg alloy vs. its conventionally cast counterpart was evaluated in simulated physiological electrolytes. The microstructural characteristics were examined by optical microscopy, SEM, TEM, and X-ray diffraction analysis. The corrosion behavior was evaluated by immersion, salt spraying, and potentiodynamic polarization. Stress corrosion resistance was assessed by Slow Strain Rate Testing. The results indicate that the corrosion resistance of rapidly solidified ribbons is significantly improved relative to the conventional cast alloy due to the increased Al content dissolved in the α-Mg matrix and the correspondingly reduced presence of the ß-phase (Mg17 Al12 ). Unfortunately, extrusion consolidated solidified ribbons exhibited a substantial reduction in the environmental performance and stress corrosion resistance. This was mainly attributed to the detrimental effect of the extrusion process, which enriched the iron impurities and increased the internal stresses by imposing a higher dislocation density. In terms of immersion tests, the average corrosion rate of the rapidly solidified ribbons was <0.4 mm/year compared with ∼2 mm/year for the conventionally cast alloy and 26 mm/year for the rapidly solidified extruded ribbons.


Assuntos
Ligas/química , Magnésio/química , Teste de Materiais , Corrosão
20.
Bull Cancer ; 101(1): 56-67, 2014 Jan 01.
Artigo em Francês | MEDLINE | ID: mdl-24491668

RESUMO

During two centuries, advances in medicine and medical research have helped to understand the pathophysiology of chronic myelogenous leukemia (CML). This hematologic malignancy is a unique model of oncogenesis where a single molecular hit, causing cell proliferation and survival, was identified. The chromosomal abnormality first highlighted by P. Nowell and D. Hungerford in 1960, and characterized as the reciprocal translocation t(9;22)(q34;q11), the Philadelphia chromosome, discovered in leukemic cells, by J. Rowley in 1973. At the end of the 20th century, the contribution of molecular biology techniques was crucial by the discovery of the BCR-ABL1 hybrid oncogene derived from the t(9;22), responsible for the translation of an aberrant protein tyrosine kinase. This BCR-ABL1 kinase deregulates signaling pathways that control normal cell cycle and survival in primitive hematopoietic cells and is thus responsible for malignant cell accumulation observed in CML. It was then only necessary to develop a targeted treatment adapted to this molecular hit. Recently, tyrosine kinase inhibitors, by their specific inhibitory activity of BCR-ABL, have revolutionized the treatment of CML, allowing rates of haematological, cytogenetic and molecular responses never seen to date, and has significantly improved the overall survival and the quality of life of patients.


Assuntos
Leucemia Mielogênica Crônica BCR-ABL Positiva/terapia , Anticorpos Monoclonais/uso terapêutico , Antineoplásicos/uso terapêutico , Arsênio/história , Arsênio/uso terapêutico , Transplante de Medula Óssea/história , Proteínas de Fusão bcr-abl/genética , História do Século XIX , História do Século XX , Humanos , Interferon-alfa/uso terapêutico , Leucemia Mielogênica Crônica BCR-ABL Positiva/genética , Leucemia Mielogênica Crônica BCR-ABL Positiva/história , Terapia de Alvo Molecular/história , Terapia de Alvo Molecular/métodos , Cromossomo Filadélfia , Radioterapia , Translocação Genética
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