RESUMEN

Rituximab safety and efficacy in patients with renal impairment have not been established, nor have the effects of hemodialysis on serum rituximab level. There are only a few published case reports assessing serum rituximab level pre- and postdialysis. No data have been published regarding the usage of rituximab in patients with continuous renal replacement therapy. The authors present a case of a 59-year-old female patient who presented with paraneoplastic tetraparesis. She was admitted to the intensive care unit due to alveolar hemorrhage with respiratory failure and acute kidney injury requiring continuous renal replacement therapy. After a diagnostic workup, the diagnosis of lymphoplasmacytic lymphoma was established. Therapy with rituximab and cyclophosphamide was started. Rituximab levels were determined in serum and dialysate. No rituximab was found in the dialysate. The patient died after 2 months in the intensive care unit from nosocomial pneumonia due to multidrug-resistant Pseudomonas aeruginosa.

A segurança e a eficácia do rituximabe em pacientes com comprometimento renal não foram estabelecidas, e o mesmo ocorre com os efeitos da hemodiálise nos níveis séricos de rituximabe. Atualmente, apenas alguns relatos de caso avaliaram o nível sérico de rituximabe antes e após a diálise. Não foram até aqui publicados dados relativos ao uso de rituximabe em pacientes sob terapia de substituição renal contínua. Os autores apresentam um caso referente a uma mulher com 59 anos de idade atendida com quadro de tetraparesia paraneoplásica. Ela foi admitida no serviço de medicina intensiva devido a hemorragia alveolar com insuficiência respiratória e lesão renal aguda, que necessitou da utilização de terapia de substituição renal contínua. Após os procedimentos diagnósticos, estabeleceu-se o diagnóstico de linfoma linfoplasmocítico. Deu-se início ao tratamento com rituximabe e ciclofosfamida. Os níveis de rituximabe foram determinados no soro e no dialisato. Não se encontrou qualquer nível de rituximabe no dialisato. A paciente faleceu após 2 meses no serviço de medicina intensiva por pneumonia nosocomial causada por Pseudomonas aeruginosa resistente a múltiplos fármacos.

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RESUMEN

RESUMO A segurança e a eficácia do rituximabe em pacientes com comprometimento renal não foram estabelecidas, e o mesmo ocorre com os efeitos da hemodiálise nos níveis séricos de rituximabe. Atualmente, apenas alguns relatos de caso avaliaram o nível sérico de rituximabe antes e após a diálise. Não foram até aqui publicados dados relativos ao uso de rituximabe em pacientes sob terapia de substituição renal contínua. Os autores apresentam um caso referente a uma mulher com 59 anos de idade atendida com quadro de tetraparesia paraneoplásica. Ela foi admitida no serviço de medicina intensiva devido a hemorragia alveolar com insuficiência respiratória e lesão renal aguda, que necessitou da utilização de terapia de substituição renal contínua. Após os procedimentos diagnósticos, estabeleceu-se o diagnóstico de linfoma linfoplasmocítico. Deu-se início ao tratamento com rituximabe e ciclofosfamida. Os níveis de rituximabe foram determinados no soro e no dialisato. Não se encontrou qualquer nível de rituximabe no dialisato. A paciente faleceu após 2 meses no serviço de medicina intensiva por pneumonia nosocomial causada por Pseudomonas aeruginosa resistente a múltiplos fármacos.

ABSTRACT Rituximab safety and efficacy in patients with renal impairment have not been established, nor have the effects of hemodialysis on serum rituximab level. There are only a few published case reports assessing serum rituximab level pre- and postdialysis. No data have been published regarding the usage of rituximab in patients with continuous renal replacement therapy. The authors present a case of a 59-year-old female patient who presented with paraneoplastic tetraparesis. She was admitted to the intensive care unit due to alveolar hemorrhage with respiratory failure and acute kidney injury requiring continuous renal replacement therapy. After a diagnostic workup, the diagnosis of lymphoplasmacytic lymphoma was established. Therapy with rituximab and cyclophosphamide was started. Rituximab levels were determined in serum and dialysate. No rituximab was found in the dialysate. The patient died after 2 months in the intensive care unit from nosocomial pneumonia due to multidrug-resistant Pseudomonas aeruginosa.

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Glioblastoma (GBM) is the most malignant primary brain tumor, with an average survival rate of 15 months. GBM is highly refractory to therapy, and such unresponsiveness is due, primarily, but not exclusively, to the glioma stem-like cells (GSCs). This subpopulation express stem-like cell markers and is responsible for the heterogeneity of GBM, generating multiple differentiated cell phenotypes. However, how GBMs maintain the balance between stem and non-stem populations is still poorly understood. We investigated the GBM ability to interconvert between stem and non-stem states through the evaluation of the expression of specific stem cell markers as well as cell communication proteins. We evaluated the molecular and phenotypic characteristics of GSCs derived from differentiated GBM cell lines by comparing their stem-like cell properties and expression of connexins. We showed that non-GSCs as well as GSCs can undergo successive cycles of gain and loss of stem properties, demonstrating a bidirectional cellular plasticity model that is accompanied by changes on connexins expression. Our findings indicate that the interconversion between non-GSCs and GSCs can be modulated by extracellular factors culminating on differential expression of stem-like cell markers and cell-cell communication proteins. Ultimately, we observed that stem markers are mostly expressed on GBMs rather than on low-grade astrocytomas, suggesting that the presence of GSCs is a feature of high-grade gliomas. Together, our data demonstrate the utmost importance of the understanding of stem cell plasticity properties in a way to a step closer to new strategic approaches to potentially eliminate GSCs and, hopefully, prevent tumor recurrence.

RESUMEN

PURPOSE: Glioblastomas (GBM) comprise 17% of all primary brain tumors. These tumors are extremely aggressive due to their infiltrative capacity and chemoresistance, with glial-to-mesenchymal transition (GMT) proteins playing a prominent role in tumor invasion. One compound that has recently been used to reduce the expression of these proteins is shikonin (SHK), a naphthoquinone with anti-tumor properties. Temozolomide (TMZ), the most commonly used chemotherapeutic agent in GBM treatment, has so far not been studied in combination with SHK. Here, we investigated the combined effects of these two drugs on the proliferation and motility of GBM-derived cells. METHODS: The cytotoxic and proliferative effects of SHK and TMZ on human GBM-derived cells were tested using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT), Ki67 staining and BrdU incorporation assays. The migration capacities of these cells were evaluated using a scratch wound assay. The expression levels of ß3 integrin, metalloproteinases (MMPs) and GMT-associated proteins were determined by Western blotting and immunocytochemistry. RESULTS: We found that GBM-derived cells treated with a combination of SHK and TMZ showed decreases in their proliferation and migration capacities. These decreases were followed by the suppression of GMT through a reduction of ß3 integrin, MMP-2, MMP-9, Slug and vimentin expression via inactivation of PI3K/AKT signaling. CONCLUSION: From our results we conclude that dual treatment with SHK and TMZ may constitute a powerful new tool for GBM treatment by reducing therapy resistance and tumor recurrence.

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