Microfluidic single cell arrays to interrogate signalling dynamics of individual, patient-derived hematopoietic stem cells.

Posted by rob on October 17, 2009 under Uncategorized | Comments are off for this article

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Microfluidic single cell arrays to interrogate signalling dynamics of individual, patient-derived hematopoietic stem cells.

Lab Chip. 2009 Sep 21;9(18):2659-64

Authors: Faley SL, Copland M, Wlodkowic D, Kolch W, Seale KT, Wikswo JP, Cooper JM

Stem cells hold great promise as a means of treating otherwise incurable, degenerative diseases due to their ability both to self-renew and differentiate. However, stem cell damage can also play a role in the disease with the formation of solid tumors and leukaemias such as chronic myeloid leukaemia (CML), a hematopoietic stem cell (HSC) disorder. Despite recent medical advances, CML remains incurable by drug therapy. Understanding the mechanisms which govern chemoresistance of individual stem cell leukaemias may therefore require analysis at the single cell level. This task is not trivial using current technologies given that isolating HSCs is difficult, expensive, and inefficient due to low cell yield from patients. In addition, hematopoietic cells are largely non-adherent and thus difficult to study over time using conventional cell culture techniques. Hence, there is a need for new microfluidic platforms that allow the functional interrogation of hundreds of non-adherent single cells in parallel. We demonstrate the ability to perform assays, normally performed on the macroscopic scale, within the microfluidic platform using minimal reagents and low numbers of primary cells. We investigated normal and CML stem cell responses to the tyrosine kinase inhibitor, dasatinib, a drug approved for the treatment of CML. Dynamic, on-chip three-color cell viability assays revealed that differences in the responses of normal and CML stem/progenitor cells to dasatinib were observed even in the early phases of exposure, during which time normal cells exhibit a significantly elevated cell death rate, as compared to both controls and CML cells. Further studies show that dasatinib does, however, markedly reduce CML stem/progenitor cell migration in situ.

PMID: 19704981 [PubMed - indexed for MEDLINE]

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Isolated extraocular muscle involvement as the ophthalmic manifestation of leukaemia.

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Isolated extraocular muscle involvement as the ophthalmic manifestation of leukaemia.

Clin Experiment Ophthalmol. 2009 Aug;37(6):609-13

Authors: Kiratli H, Balci KE, Himmetoğlu C, Uner A

BACKGROUND: Clinical and imaging features of patients with orbital leukaemia primarily involving extraocular muscles were evaluated. METHODS: This retrospective case series includes patients with leukaemia whose only ophthalmic manifestation was extraocular muscle enlargement. Demographic data, clinical information on the systemic disease, prominent ocular signs and symptoms, computed tomography and magnetic resonance imaging characteristics, treatments applied and the outcomes were collected. RESULTS: Five patients were diagnosed as leukaemic infiltration of extraocular muscle between 1995 and 2008. The age at presentation ranged between 3 and 61 years. Acute myeloid leukaemia was the diagnosis in two patients, and chronic lymphocytic leukaemia, chronic myeloid leukaemia and biphenotypic acute leukaemia were found in one patient each, respectively. One patient had bilateral involvement. The lateral rectus muscle was affected in four patients and the superior rectus muscle in one case. Restricted ocular motility was the most common finding. In one patient who had no prior history of leukaemia, an incisional biopsy established the diagnosis. All patients received multi-agent chemotherapy. Four patients expired after a rapid decline of the systemic status within a mean period of 7 months. CONCLUSIONS: Leukaemic infiltration of extraocular muscles is a rare and late manifestation of the advanced disease associated with relapse and there seems to be a predilection for the lateral rectus muscle. Systemic prognosis remains dismal despite intensive chemotherapy.

PMID: 19702712 [PubMed - indexed for MEDLINE]

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