2,126 research outputs found
Impact of global SST gradients on the Mediterranean runoff changes across the Plio-Pleistocene transition
This work explores the impact of the development of global meridional and zonal sea surfacetemperature (SST) gradients on the Mediterranean runoff variability during the Plio-Pleistocene transition,about 3 Ma. Results show that total annual mean Pliocene Mediterranean runoff is about 40% larger thanduring the preindustrial period due to more increased extratropical specific humidity. As a consequenceof a weakened and extended Hadley cell, the Pliocene northwest Africa hydrological network producesa discharge 30 times larger than today. Our results support the conclusion that during the Pliocene, theMediterranean water deficit was reduced relative to today due to a larger river discharge. By means ofa stand-alone atmospheric general circulation model, we simulate the separate impact of extratropicaland equatorial SST cooling on the Mediterranean runoff. While cooling the equatorial SST does not implysignificant changes to the Pliocene Mediterranean hydrological budget, the extratropical SST coolingincreases the water deficit due to a decrease in precipitation and runoff. Consequently, river dischargefrom this area reduces to preindustrial levels. The main teleconnections acting upon the Mediterraneanarea today, i.e., the North Atlantic Oscillation during winter and the “monsoon-desert” mechanism duringsummer already have a large influence on the climate of our Pliocene simulations. Finally, our results alsosuggest that in a climate state significantly warmer than today, changes of the Hadley circulation couldpotentially lead to increased water resources in northwest Africa
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Laser-driven acceleration of quasi-monoenergetic, near-collimated titanium ions via a transparency-enhanced acceleration scheme
Laser-driven ion acceleration has been an active research area in the past two decades with the prospects of designing novel and compact ion accelerators. Many potential applications in science and industry require high-quality, energetic ion beams with low divergence and narrow energy spread. Intense laser ion acceleration research strives to meet these challenges and may provide high charge state beams, with some successes for carbon and lighter ions. Here we demonstrate the generation of well collimated, quasi-monoenergetic titanium ions with energies ∼145 and 180 MeV in experiments using the high-contrast(<10-9) and high-intensity (6× 1020 W cm-2) Trident laser and ultra-Thin (∼100 nm) titanium foil targets. Numerical simulations show that the foils become transparent to the laser pulses, undergoing relativistically induced transparency (RIT), resulting in a two-stage acceleration process which lasts until ∼2 ps after the onset of RIT. Such long acceleration time in the self-generated electric fields in the expanding plasma enables the formation of the quasi-monoenergetic peaks. This work contributes to the better understanding of the acceleration of heavier ions in the RIT regime, towards the development of next generation laser-based ion accelerators for various applications
Immunophenotypic characterization of plasma cells in patients with multiple myeloma
INTRODUCTION AND OBJECTIVE: Multiple myeloma is an incurable malignancy characterized by the proliferation of a single clone of plasma cells in bone marrow. The aim of this study was to evaluate the frequency and prognostic value of the expression of aberrant phenotypes in patients with multiple myeloma by multiparametric flow cytometry. METHODS: The study was carried out at Department of Hematology and Hemotherapy of Federal University of São Paulo and 30 patients with MM were analyzed prospectively. In an attempt to identify myeloma cells by flow cytometry (FACSCalibur, BD), specific monoclonal antibodies anti-CD138, anti-CD38 and anti-CD45 were used for the selection of plasma cells. The control group comprised four healthy bone marrow donors. RESULTS: All myeloma plasma cells expressed at least one aberrant phenotype and CD56+++, CD117++, CD33++, CD13++ and CD28++ markers were more frequently observed in 88% of patients. Lymphoid markers were found in cases with a higher number of aberrant phenotypes. DISCUSSION: CD56+++ and CD28++ antigens showed high levels of β2-microglobulin, which are associated with more aggressive stages of the disease and larger tumor mass. The absence of adhesion molecule CD56 was associated with high levels of β2M and calcium ion, showing that this finding may have prognostic value. CONCLUSION: From this study it was concluded that the aberrant phenotypes are present in most cases of MM, and immunophenotyping by multiparametric flow cytometry is a useful tool to distinguish normal plasma cells from myeloma plasma cells.INTRODUÇÃO E OBJETIVO: O mieloma múltiplo (MM) é uma doença maligna incurável caracterizada pela proliferação de um único clone de plasmócitos na medula óssea. O objetivo deste estudo foi avaliar a frequência e o valor prognóstico da expressão dos fenótipos aberrantes em pacientes com MM por meio de citometria de fluxo multiparamétrica. MÉTODOS: O estudo foi realizado no Hospital São Paulo/Disciplina de Hematologia e Hemoterapia da Universidade Federal de São Paulo (UNIFESP), sendo analisados de maneira prospectiva 30 pacientes portadores de MM ao diagnóstico. Na tentativa de identificar as células mielomatosas por citometria de fluxo (FACScalibur, BD), foram utilizados anticorpos monoclonais anti-CD138, anti-CD38, anti-CD45 específicos para seleção dos plasmócitos. O grupo controle consistiu em quatro doadores saudáveis de medula óssea. RESULTADOS: Todos os plasmócitos mielomatosos expressaram pelo menos um fenótipo aberrante, e CD56+++, CD117++, CD33++, CD13++, CD28++ foram os marcadores mais frequentes, observados em 88% dos pacientes. Os marcadores linfoides foram encontrados nos casos com maior número de fenótipos aberrantes. DISCUSSÃO: Os antígenos CD56+++ e CD28++ apresentaram altos níveis de β2-microglobulina, sendo estes associados a estágios mais agressivos da doença e maior massa tumoral. A ausência da molécula de adesão CD56 foi relacionada com altos níveis de β2M e de cálcio iônico, mostrando que este achado pode ter valor prognóstico. CONCLUSÃO: A partir deste estudo concluiu-se que os fenótipos aberrantes estão presentes na maioria dos casos de MM e que a imunofenotipagem por citometria de fluxo multiparamétrica é uma boa ferramenta para distinguir células plasmáticas normais dos plasmócitos mielomatosos.Universidade Federal de PernambucoCentro de Estudos Superiores de Maceió Faculdade de Ciências Biológicas e da SaúdeUNIFESPUNIFESPSciEL
High incidence of chromosomal numerical abnormalities by multicentromeric FISH in multiple myeloma patients
This study aimed to characterize genetic alterations by interphase multicentromeric FISH focusing on chromosomal numerical abnormalities and using some locus specific probes for the most frequent aberrations found in the disease, in a homogeneous cohort of 34 advanced stage, but recently diagnosed MM patients; 97% had numerical chromosomal abnormalities detected by FISH, being 75% hyperdiploid, 18% hypodiploid and 3% tri/tetraploid. Using locus specific probes, we found 13q deletion in 30% and IGH rearrangement in 25% of cases. Grouping hypodiploid patients together with del13q (unfavorable group) and comparing them to the remaining cases (non unfavorable group) we found a trend towards younger patients presenting more unfavorable abnormalities (p = 0.06) and significant lower hemoglobin level (Hb < 8.5 mg/dl, p = 0.03).Este estudo objetivou detectar as alterações genéticas em pacientes com mieloma múltiplo (MM), usando o método de hibridação in situ por fluorescência em interfases (FISH interfásico). Para detectar as alterações numéricas foram usadas sondas multicentroméricas e para os rearranjos mais freqüentemente observados na doença foram utilizadas as sondas lócus específicas para IGH, P53, ciclina D1 e RB1. Foram estudados 34 pacientes com MM em estágio avançado, ainda que recém-diagnosticados, 97% dos quais apresentaram anormalidades numéricas detectadas por FISH, sendo 75% hiperdiplóides, 18% hipodiplóides e 3% tri/tetraplóides. Em relação às demais anormalidades, a deleção 13q foi encontrada em 30% dos casos e o rearranjo IGH, em 25%. Agrupando os pacientes com hipodiploidia e com deleção 13q14 (grupo desfavorável) e comparando-os com os demais (grupo não-desfavorável), houve tendência a pacientes jovens no grupo desfavorável (p = 0,06) e níveis de hemoglobina (Hb) significativamente mais baixos (< 8,5 g/dl, p = 0,03).Universidade Federal de São Paulo (UNIFESP)UNIFESPSciEL
A new concurrent chemotherapy with vinorelbine and mitomycin C in combination with radiotherapy in patients with locally advanced squamous cell carcinoma of the head and neck
Objective: The purpose of this pilot study was to evaluate the feasibility and toxicity of concurrent chemotherapy with vinorelbine and mitomycin C in combination with accelerated radiotherapy (RT) in patients with locally advanced cancer of the head and neck. Patients and Methods: Between January 2003 and March 2004, 15 patients with T4/N2-3 squamous cell carcinoma (12/15) and with N3 cervical lymph node metastases of carcinoma of unknown primary (3/15) were treated with chemotherapy and simultaneous accelerated RT. Results: 11 patients completed therapy without interruption or dose reduction. Grade 3 - 4 acute mucosal toxicity was observed in 9/15 patients, grade 4 hematologic toxicity in 6/15 patients. At a median follow-up of 7.5 months, 2 patients have died of intercurrent disease, 2 patients have experienced local relapse; 5 patients are alive with no evidence of disease at the primary tumor site. Discussion: The described regimen is highly effective, but led to remarkable side effects
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