Human pluripotent stem cells (hPSCs) are a powerful tool for modeling brain development and disease. The human cortex is composed of two major neuronal populations, projection neurons and local interneurons. Cortical interneurons comprise a diverse class of cell types expressing the neurotransmitter GABA. Dysfunction of cortical interneurons has been implicated in neuropsychiatric diseases, including schizophrenia, autism and epilepsy. Here we demonstrate the highly efficient derivation of human cortical interneurons in a NKX2.1::GFP hESC reporter line. Manipulating the timing of SHH activation yields three distinct GFP+ populations with specific transcriptional profiles, neurotransmitter phenotypes and migratory behaviors. Further differentiation in a murine cortical environment yields parvalbumin and somatostatin expressing neurons that exhibit synaptic inputs and electrophysiological properties of cortical interneurons. Our study defines the signals sufficient to model human ventral forebrain development in vitro and lays the foundation for studying cortical interneuron involvement in human disease pathology.

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Context Surgical site infection (SSI) in the general surgical population is a significant public health issue. The use of a high fractional inspired concentration of oxygen (FIO 2 ) during the perioperative period has been reported to be of benefit in selected patients, but its role as a routine intervention has not been investigated.Objective To determine whether the routine use of high FIO 2 during the perioperative period alters the incidence of SSI in a general surgical population.Design, Setting, and Patients Double-blind, randomized controlled trial conducted between September 2001 and May 2003 at a large university hospital in metropolitan New York City of 165 patients undergoing major intra-abdominal surgical procedures under general anesthesia.Interventions Patients were randomly assigned to receive either 80% oxygen (FIO 2 of 0.80) or 35% oxygen (FIO 2 of 0.35) during surgery and for the first 2 hours after surgery.Main Outcome Measures Presence of clinically significant SSI in the first 14 days after surgery, as determined by clinical assessment, a management change, and at least 3 prospectively defined objective criteria. ResultsThe study groups were closely matched in a large number of clinical variables. The overall incidence of SSI was 18.1%. In an intention-to-treat analysis, the incidence of infection was significantly higher in the group receiving FIO 2 of 0.80 than in the group with FIO 2 of 0.35 (25.0% vs 11.3%; P=.02). FIO 2 remained a significant predictor of SSI (P=.03) in multivariate regression analysis. Patients who developed SSI had a significantly longer length of hospitalization after surgery (mean [SD], 13.3 [9.9] vs 6.0 [4.2] days; PϽ.001). ConclusionsThe routine use of high perioperative FIO 2 in a general surgical population does not reduce the overall incidence of SSI and may have predominantly deleterious effects. General surgical patients should continue to receive oxygen with cardiorespiratory physiology as the principal determinant.

. Whole cell patch-clamp recordings were obtained from thalamic ventrobasal (VB) and reticular (RTN) neurons in mouse brain slices. A bicuculline-sensitive tonic current was observed in VB, but not in RTN, neurons; this current was increased by the GABA A receptor agonist 4,5,6,7-tetrahydroisothiazolo-[5,4-c]pyridine-3-ol (THIP; 0.1 M) and decreased by Zn 2ϩ (50 M) but was unaffected by zolpidem (0.3 M) or midazolam (0.2 M). The pharmacological profile of the tonic current is consistent with its generation by activation of GABA A receptors that do not contain the ␣ 1 or ␥ 2 subunits. GABA A receptors expressed in HEK 293 cells that contained ␣ 4 ␤ 2 ␦ subunits showed higher sensitivity to THIP (gaboxadol) and GABA than did receptors made up from ␣ 1 ␤ 2 ␦, ␣ 4 ␤ 2 ␥ 2s, or ␣ 1 ␤ 2 ␥ 2s subunits. Western blot analysis revealed that there is little, if any, ␣ 3 or ␣ 5 subunit protein in VB. In addition, co-immunoprecipitation studies showed that antibodies to the ␦ subunit could precipitate ␣ 4 , but not ␣ 1 subunit protein. Confocal microscopy of thalamic neurons grown in culture confirmed that ␣ 4 and ␦ subunits are extensively co-localized with one another and are found predominantly, but not exclusively, at extrasynaptic sites. We conclude that thalamic VB neurons express extrasynaptic GABA A receptors that are highly sensitive to GABA and THIP and that these receptors are most likely made up of ␣ 4 ␤ 2 ␦ subunits. In view of the critical role of thalamic neurons in the generation of oscillatory activity associated with sleep, these receptors may represent a principal site of action for the novel hypnotic agent gaboxadol. I N T R O D U C T I O NThe activation of GABA A receptors inhibits neurons in two ways-via a fast or transient inhibition after GABA binding to synaptically localized receptors and by a sustained inhibition due to GABA binding to extrasynaptic receptors (Brickley et al. 1996; Farrant and Nusser 2005;Kaneda et al. 1995;Mody 2001). Extrasynaptic receptors are excellent sensors for extracellular GABA due to their high affinity for GABA and slow rates of desensitization (Bai et al. 2001; Brickley et al. 1999;Yeung et al. 2003). The activation of these receptors regulates neuronal input resistance and, hence, excitability (Brickley et al. 2001;Semyanov et al. 2003). The ␦ subunit appears to be present in many extrasynaptic GABA A receptors. In cerebellar granule cells, these receptors likely contain ␣ 6 , ␤, and ␦ subunits (Brickley et al. 2001;Nusser et al. 1998;Pirker et al. 2000), whereas granule cells in the dentate gyrus likely contain ␣ 4 , ␤, and ␦ subunits (Nusser and Mody 2002;Sperk et al. 1997;Sun et al. 2004;Wei et al. 2003). Extrasynaptic GABA A receptors in CA1 pyramidal neurons in the hippocampus, however, likely contain ␣ 5 , ␤ 2/3 , and ␥ 2 subunits (Caraiscos et al. 2004).Several GABA A receptor subunits are expressed in the thalamus. ␣ 1 , ␣ 4 , ␤ 2 , ␥ 2 , and ␦ subunits are found in thalamocortical neurons in the ventrobasal (VB) complex, whereas ␣ 3 , ␤ 3 , and ␥ 2 subunits...

In the course of primary infection with herpes simplex virus 1 (HSV-1), children with inborn errors of TLR3 immunity are prone to HSV-1 encephalitis (HSE) 1–3. We tested the hypothesis that the pathogenesis of HSE involves non hematopoietic central nervous system (CNS)-resident cells. We derived induced pluripotent stem cells (iPSCs) from the dermal fibroblasts of TLR3- and UNC-93B-deficient patients and from controls. These iPSCs were differentiated into highly purified populations of neural stem cells (NSCs), neurons, astrocytes and oligodendrocytes. The induction of IFN-β and/or IFN-γ1 in response to poly(I:C) stimulation was dependent on TLR3 and UNC-93B in all cells tested. However, the induction of IFN-β and IFN-γ1 in response to HSV-1 infection was impaired selectively in UNC-93B-deficient neurons and oligodendrocytes. These cells were also much more susceptible to HSV-1 infection than control cells, whereas UNC-93B-deficient NSCs and astrocytes were not. TLR3-deficient neurons were also found to be susceptible to HSV-1 infection. The rescue of UNC-93B- and TLR3-deficient cells with the corresponding wild-type allele demonstrated that the genetic defect was the cause of the poly(I:C) and HSV-1 phenotypes. The viral infection phenotype was further rescued by treatment with exogenous IFN-α/β, but not IFN-γ1.Thus, impaired TLR3- and UNC-93B-dependent IFN-α/β intrinsic immunity to HSV-1 in the CNS, in neurons and oligodendrocytes in particular, may underlie the pathogenesis of HSE in children with TLR3 pathway deficiencies.