A high selective membrane permeability to potassium ions (K + ) and a strongly negative resting membrane potential (RMP) are considered fundamental properties of glial cells [1,2]. Glia express a wide range of K + channels, but inwardly rectifying K + channels (Kir) are predominantly responsible for the high K + permeabili- AbstractGlia in the central nervous system (CNS) express diverse inward rectifying potassium channels (Kir). The major function of Kir is in establishing the high potassium (K + ) selectivity of the glial cell membrane and strongly negative resting membrane potential (RMP), which are characteristic physiological properties of glia. The classical property of Kir is that K + flows inwards when the RMP is negative to the equilibrium potential for K + (E K ), but at more positive potentials outward currents are inhibited. This provides the driving force for glial uptake of K + released during neuronal activity, by the processes of "K + spatial buffering" and "K + siphoning", considered a key function of astrocytes, the main glial cell type in the CNS. Glia express multiple Kir channel subtypes, which are likely to have distinct functional roles related to their differences in conductance, and sensitivity to intracellular and extracellular factors, including pH, ATP, G-proteins, neurotransmitters and hormones. A feature of CNS glia is their specific expression of the Kir4.1 subtype, which is a major K + conductance in glial cell membranes and has a key role in setting the glial RMP. It is proposed that Kir4.1 have a primary function in K + regulation, both as homomeric channels and as heteromeric channels by co-assembly with Kir5.1 and probably Kir2.0 subtypes. Significantly, Kir4.1 are also expressed by oligodendrocytes, the myelin-forming cells of the CNS, and the genetic ablation of Kir4.1 results in severe hypomyelination. Hence, Kir, and in particular Kir4.1, are key regulators of glial functions, which in turn determine neuronal excitability and axonal conduction.

Deletion studies in transgenic mice indicate that the potassium inward rectifying channel Kir4.1 is crucial for oligodendrocyte differentiation and has a special role in regulation of extracellular potassium (

The human T-cell leukemia virus type II (HTLV-II) regulatory protein Rex augments cytoplasmic levels of unspliced gag-pol mRNA by acting through a Rex-responsive element (RxRE) in the long terminal repeat. Purified Rex protein binds to long terminal repeat mRNA. Here, using an immunobinding assay to measure the binding of Rex protein to mutated RxRE RNAs, we show that efficient Rex binding requires a stem-bulge-loop RNA secondary structure (nucleotides [nt] 465 to 500) and specific sequences both within the stem-bulge (nt 470 to 476) and within a conserved upstream splice donor site (nt 449 to 455). Rex function in a transient transfection expression system correlates with Rex protein-RxRE RNA binding. The ability of HTLV-II Rex to interact directly with the HTLV-ll splice donor site suggests that HTLV-II Rex may increase expression of unspliced gag-pol mRNA, in part, by inhibiting splicing.

OctaplasLG is indicated for use in patients undergoing cardiac surgery who require replacement of multiple clotting factors. The use of OctaplasLG over single-donor fresh frozen plasma (FFP) may have beneficial effects when considering the transmission of enveloped viruses. Additionally, it has the potential for fewer adverse reactions, reduced disease transmission, and a more homogenous coagulation factor composition. However, its efficacy and safety have not yet been evaluated in the pediatric population. Pediatric patients aged less than 2 years old and less than 10 kg, who underwent complete tetralogy of Fallot repair and received either OctaplasLG or FFP intraoperatively were identified over a 10-year period for this retrospective analysis. A review of case notes, intra-operative, and laboratory data were used to assess intraoperative blood product usage, blood loss, and postoperative coagulopathy. Data were analyzed to assess the efficacy of OctaplasLG in achieving hemostasis when compared to FFP. Results showed clinically better hemostasis postoperatively in OctaplasLG group compared with FFP group and better coagulation results. OctaplasLG was as effective as FFP when used in pediatric patients undergoing cardiac surgery.