Background and Purpose-The importance of bioactive lipid signaling under physiological and pathophysiological conditions is progressively becoming recognized. The disparate distribution of sphingosine kinase (SphK) isoform activity in normal and ischemic brain, particularly the large excess of SphK2 in cerebral microvascular endothelial cells, suggests potentially unique cell-and region-specific signaling by its product sphingosine-1-phosphate. The present study sought to test the isoform-specific role of SphK as a trigger of hypoxic preconditioning (HPC)-induced ischemic tolerance. Methods-Temporal changes in microvascular SphK activity and expression were measured after HPC. The SphK inhibitor dimethylsphingosine or sphingosine analog FTY720 was administered to adult male Swiss-Webster ND4 mice before HPC. Two days later, mice underwent a 60-minute transient middle cerebral artery occlusion and at 24 hours of reperfusion, infarct volume, neurological deficit, and hemispheric edema were measured. Results-HPC rapidly increased microvascular SphK2 protein expression (1.7Ϯ0.2-fold) and activity (2.5Ϯ0.6-fold), peaking at 2 hours, whereas SphK1 was unchanged. SphK inhibition during HPC abrogated reductions in infarct volume, neurological deficit, and ipsilateral edema in HPC-treated mice. FTY720 given 48 hours before stroke also promoted ischemic tolerance; when combined with HPC, even greater (and dimethylsphingosine-reversible) protection was noted. Conclusions-These findings indicate hypoxia-sensitive increases in SphK2 activity may serve as a proximal trigger that ultimately leads to sphingosine-1-phosphate-mediated alterations in gene expression that promote the ischemia-tolerant phenotype. Thus, components of this bioactive lipid signaling pathway may be suitable therapeutic targets for protecting the neurovascular unit in stroke. (Stroke. 2009;40:3342-3348.)

✓ Selective dorsal rhizotomy is a well-established surgical procedure for improving lower-extremity spasticity in children with cerebral palsy. The standard technique requires an L1–S1 laminectomy or laminoplasty for visualization of all dorsal nerve roots exiting at their respective foramina. The authors describe a rhizotomy procedure that requires a single-level laminectomy at the level of the conus, with the advantages of decreased operating time and postoperative pain as well as a minimal risk of progressive lumbar instability. This procedure is both effective and well tolerated in appropriately selected children and adults, and has had one cerebrospinal fluid lead requiring operative repair in more than 1500 patients treated at the authors' institution since 1991.

Object Intraventricular hemorrhage (IVH) and progressive posthemorrhagic ventricular dilation (PPHVD) may result in significant neurological morbidity in preterm infants. At present, there is no consensus regarding the optimal timing or type of neurosurgical procedure to best treat PPHVD. Conflicting data exist regarding the relative risks and benefits of two commonly used temporizing neurosurgical procedures (TNPs), ventricular access devices ([VADs] or ventricular reservoirs) versus ventriculosubgaleal (VSG) shunts. This study was designed to address this issue. Methods This is a single-center, 10-year retrospective review of all preterm infants admitted to the St. Louis Children's Hospital neonatal intensive care unit (NICU) with Papile Grade III–IV IVH. The development of PPHVD and the requirement for and type of TNP were recorded. Rates of TNP complication, ventriculoperitoneal (VP) shunt implantation, shunt infection, and mortality rates were used to compare the efficacy and limitations of each TNP type. Results Over this 10-year interval, 325 preterm infants with Grade III–IV IVH were identified, with trends showing an increasing number of affected infants annually, and an increasing number of TNPs were required annually. Ninety-five (29.2%) of the 325 infants underwent a TNP for PPHVD (65 VADs, 30 VSG shunts). The rate of permanent VP shunt implantation for all TNPs was 72.6% (69 of 95 infants). Forty-nine (75.4%) of the 65 infants treated with VADs and 20 (66.7%) of the 30 treated with VSG shunts required VP shunts (p = 0.38). There was no statistical difference between VAD or VSG shunt with regard to TNP-related infection (p = 0.57), need for TNP revision (p = 0.16), subsequent shunt infection (p = 0.77), shunt revision rate (p = 0.58), or mortality rate (p = 0.24). Conclusions Rates of IVH and PPHVD observed at the authors' center have increased over time. In contrast to recent literature, the results from the current study did not demonstrate a difference in complication rate or requirement for permanent VP shunt placement between VADs and VSG shunts. Definitive conclusions will require a larger, prospective trial.

Mean platelet volume (MPV) has been actively investigated in liver disease such as steatosis, cirrhosis and hepatitis. Recently, MPV/platelet count (PC) ratio has been proposed as a predictor of long-term mortality after myocardial infarction. As PC is known to be decreased in various liver diseases such as cirrhosis, hepatosplenomegaly and malignancy, we planned to evaluate MPV/PC ratio in patients with hepatocellular carcinoma (HCC) in this study. Mean of MPV levels showed significant difference, which were 8.69 fl (range 6.7-12.2 fl) in patients group and 8.02 fl in control group (range 6.7-11.0 fl). In receiver operating characteristic (ROC) curve analysis, the MPV/PC ratio (fl/(10(9)/l)) presented 74.5% of sensitivity and 96.5% of specificity at the criterion > 0.0491 (area under the curve (AUC) = 0.884), while MPV alone showed 57.4% of sensitivity and 81.4% of specificity at the criterion > 8.4 fl. Further studies should evaluate underlying pathogenic mechanisms of MPV/PC ratio difference and various possibilities of this ratio as an indicator of presence of a tumor in HCC.