During mouse development, the ventral spinal cord becomes organized into five progenitor domains that express different combinations of transcription factors and generate different subsets of neurons and glia. One of these domains, known as the p2 domain, generates two subtypes of interneurons, V2a and V2b. Here we have used genetic fate mapping and loss-of-function analysis to show that the transcription factor Sox1 is expressed in, and is required for, a third type of p2-derived interneuron, which we named V2c. These are close relatives of V2b interneurons, and, in the absence of Sox1, they switch to the V2b fate. In addition, we show that late-born V2a and V2b interneurons are heterogeneous, and subsets of these cells express the transcription factor Pax6. Our data demonstrate that interneuron diversification in the p2 domain is more complex than previously thought and directly implicate Sox1 in this process.

Familial Mediterranean Fever (FMF) is an autosomal recessive disease of high prevalence within Mediterranean countries and particularly common in four ethnic populations: Arabs, non-Ashkenazi Jews, Armenians, and Turks. The responsible gene MEFV has been assigned to chromosome 16p13.3. Our aim was to establish the frequencies of the most common mutations in Greek-Cypriots. We found that 1 in 25 is a carrier of one of three mutations. V726A, M694V, and F479L. In 68 Grek-Cypriot FMF chromosomes analyzed, we found V726A (25%), F479L (20.6%), M694V (17.6%), and others (36.8%). Mutation F479L, relatively common in this population, is very rare elsewhere. Our study indicates that FMF is not a rare condition in Cyprus and that, because of the significant morbidity associated with this disorder, which is often diagnosed only after unnecessary surgeries, a newborn screening program to detect affected in this population may be warranted.

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Maintaining optimal blood glucose (Glu) and insulin (Ins) levels is essential for physiological studies in anesthetized mice. This study examined the temporal effects of varying levels of isoflurane (ISO) anesthesia on blood Glu and Ins levels in mice for 90 min. post‐induction. Male C57BL/6 mice were allowed to breath freely ISO at 1 (n=5), 1.5 (n=7), and 2.0% (n=8) in 100% O2 while body temperature was maintained at 37.1±0.4°C. ECG and respiratory flowrate were monitored. A 0.6μl tail vein blood aliquot was extracted at 5 min. intervals for Glu measurements. Ins was measured from 1ml arterial blood at 1 and 2% ISO in 20 mice euthanized at t=0, 20, 40, 60 and 80 min. Mean heart rates (±SD) were 532±39, 488±39, and 449±23 bpm at 1, 1.5, and 2% ISO respectively (p<0.0001). Glu concentrations (mg/dl) ranged between 155±28–196±76 [1% ISO], 162±43–239±38 [1.5% ISO], and 159±52–205±49 [2.0% ISO]. Ins values ranged between 3.5±0.3–4.2±0.6ng/dl [2% ISO], and 3.4±0.5–4.2±0.9ng/dl at 1% ISO. Glu values were significantly higher in the ISO=1.5 and 2% groups compared to the 1% group (p<0.0001). No significant temporal change was noted in Glu values at the 3 ISO doses. Ins concentrations did not differ significantly between groups. The results confirm that ISO levels ≥1.5% produce a mild hyperglycemic effect, prominent at later time periods post‐induction.Research supported by the Hellenic Bank and the Research Promotion Foundation.

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This study examines (a) the temporal stability of hemodynamic indices of systolic and diastolic function in C57BL/6 mice under 1.5% isoflurane (ISO) (v/v) anesthesia conditions in 50:50 O(2)/N(2)O (v/v) within 90 min post-induction, and (b) the effects of Mn(2+) on the mouse hemodynamic response in male C57BL/6 mice (n = 16). Left ventricular catheterizations allowed estimation of the hemodynamic indices. Hypertonic saline infusion (10%) allowed absolute volume quantification in conjunction with a separate series of aortic flow experiments (n = 3). In a separate cohort of mice (n = 6), MnCl(2) (190 nmoles/g/bw) was infused via the left jugular for 29-39 min, following 11 min of baseline recording, to assess temporal responses. Stable temporal hemodynamic responses were achieved in control mice under ISO anesthesia. Hemodynamic indices during control, time-matched-control, baseline-Mn, and Mn-infused periods, were within normal expected ranges. No chronotropic changes were observed. Significant differences in systolic and diastolic cardiac indices of function (HR, EF, ESP, dP/dt (max), dP/dt (min), PAMP, τ(glantz), and τ(weiss)) resulted between baseline-Mn and Mn-infused time periods in Mn-treated mice at the 1% significance (p < 0.001). Transient positive, or negative, or positive followed by negative evoked pressure-volume loop shifts were observed (exemplified through changes in the end-systolic pressure-volume relationship and dP/dt (max)) in Mn-infusion studies. It is concluded that Mn(2+) can be used safely for prolonged mouse imaging studies, however, the significant variations elicited in cardiovascular hemodynamics post-manganese infusion, necessitate further investigations for its suitability and appropriateness for quantification of global cardiac function in image-based phenotyping.

The Silver Standard? Enzyme mismatch cleavage is a sensitive and accurate method for mutation detection. The approach entails bacteriophage resolvase cleavage of heteroduplex DNA formed by the annealing of a mutant and a wild-type strand, one of which has been end-labeled with a radioactive or fluorescent moiety, followed by electrophoresis through a native polyacrylamide gel. Mean et al. (p. 758) modify the original protocol using T7 endonuclease I as the cleavase, coupled with visualization of cleaved fragments by silver staining following electrophoresis. They compare results obtained with the modified procedure to those obtained using single-stranded conformational polymorphism (SSCP) and show that the new protocol detects mutations with significantly increased sensitivity and specificity. Whereas earlier procedures are capable of detecting only the labeled cleavage product, the modified protocol has the advantage of detecting both fragments. This protocol provides a simple and cost-effective alternative to existing approaches to mutation detection and will make mutation detection analysis more financially accessible.