Simultaneous measurement of [Ca(2+)](i) and I(m) in voltage-clamped gonadotrophs revealed that GnRH stimulates an increase in [Ca(2+)](i) that precedes outward I(m), and that activates two kinetically distinct currents identified, using specific toxin inhibitors, as small conductance Ca(2+)-activated K(+) (S(K)) current (I(SK)) and large (big) conductance voltage-and Ca(2+)-activated K(+) (BK) current (I(BK)). We show that the apamin-sensitive current has an IC(50) of 69 pM, consistent with the SK2 channel subtype and confirmed by immunocytochemistry. URMC-099 cost The magnitude of the SK current response to GnRH was attenuated by 17 beta-estradiol (E(2)) pretreatment. Iberiotoxin,

an inhibitor of BK channels, completely blocked the residual apamin-insensitive outward I(m), substantiating that I(BK) is a component of the GnRH-induced outward I(m). In contrast

to its suppression of I(SK), E(2) pretreatment augmented peak I(BK). SK or BK channel inhibition modulated GnRH-stimulated LH secretion, implicating a role for these channels in gonadotroph function. In summary, in mouse gonadotrophs the GnRH-stimulated increase in [Ca(2+)] i activates I(SK) and I(BK), which are differentially regulated by E(2) and which may be targets for E(2) positive feedback in LH secretion. (Endocrinology 150: 2264-2272, 2009)”
“The purpose of this study was to provide a culture method for an effective expansion of human CD 34 positive hematopoietic progenitor cells selleck kinase inhibitor (CD 34 (+) HCs) utilizing low molecular CB-839 purchase weight heparin/protamine microparticles (LH/P MPs) which can be stably coated onto plastic

surfaces and cytokines. CD 34 (+) HCs optimally proliferated on LH/P MP-coated plates in the presence of stem cell factor (SCF; 5 ng/ml), thrombopoietin (Tpo; 10 ng/ml), and Flt-3 ligand (Flt-3; 10 ng/ml) in hematopoietic progenitor growth medium (HPGM). After 6 days, the total cells expanded 16.5-fold. Those cytokines were shown to be partially immobilized on the LH/P MP-coated plates, and the immobilized cytokines were gradually released into the medium with half releasing time of 3-4 days. Since flow cytometry analyses revealed that 90% of initial cells and 44.5% of expanded cells were CD 34 positive, CD 34 (+) HCs were estimated to have increased 8.0-fold after 6 days, and to have increased to over 31.9-fold after 12 days. In contrast, cultured CD 34 (+) HCs on non-coated tissue culture plates increased only 2.9-fold in the identical medium after 6 days, and only 5.2-fold after 12 days. (C) 2008 Elsevier B.V. All rights reserved.”
“Malarial infection is associated with complex immune and erythropoietic responses in the host. A quantitative understanding of these processes is essential to help inform malaria therapy and for the design of effective vaccines.