Age-dependent neurological phenotypes in a mouse model of PRRT2-related diseases

Paroxysmal kinesigenic dyskinesia is an episodic movement disorder caused by dominant mutations in the proline-rich transmembrane protein PRRT2, with onset in childhood and typically with improvement or resolution by middle age. Mutations in the same gene may also cause benign infantile seizures, which begin in the first year of life and typically remit by the age of 2 years. Many details of PRRT2 function at the synapse, and the effects of mutations on neuronal excitability in the pathophysiology of epilepsy and dyskinesia, have emerged through the work of several groups over the last decade. However, the age dependence of the phenotypes has not been explored in detail in transgenic models. Here, we report our findings in heterozygous and homozygous Prrt2 knockout mice that recapitulate the age dependence of dyskinesia seen in the human disease. We show that Prrt2 deletion reduces the levels of synaptic proteins in a dose-dependent manner that is most pronounced at postnatal day 5 (P5), attenuates at P60, and disappears by P180. In a test for foot slippage while crossing a balance beam, transient loss of coordination was most pronounced at P60 and less prominent at age extremes. Slower traverse time was noted in homozygous knockout mice only, consistent with the ataxia seen in rare individuals with biallelic loss of function mutations in Prrt2. We thus identify three age-dependent phenotypic windows in the mouse model, which recapitulate the pattern seen in humans with PRRT2-related diseases.

     

Systematic Review and Meta-analysis of Enhanced Recovery After Pancreatic Surgery with Particular Emphasis on Pancreaticoduodenectomies

Background

In the past decade, Enhanced Recovery after Surgery (ERAS) protocols have been implemented in several fields of surgery. With these protocols, a faster recovery and shorter hospital stay can be accomplished without an increase in morbidity or mortality. The purpose of this study was to review systematically the evidence for implementation of an ERAS protocol in pancreatic resections, with particular emphasis on pancreaticoduodenectomies (PDs).

Methods

A systematic search was performed in Medline, Embase, Pubmed, CINAHL, and the Cochrane library for papers describing an ERAS program in adult patients undergoing elective pancreatic surgery published between January 1966 and December 2012. The primary outcome measure was postoperative length of stay. Secondary outcome measures were time to recovery of normal function, overall postoperative complication rates, readmissions, and mortality. Subsequently, a meta-analysis of outcome measures focusing on PD was conducted. This systematic review and meta-analysis was performed according to the PRISMA statement.

Results

The literature search produced 248 potentially relevant papers. Of these, eight papers met the predefined inclusion criteria: five case-control studies, two retrospective studies, and one prospective study, describing a total of 1,558 patients. Only three of the studies reported data on discharge criteria and assessed time to recovery and return to normal function. Implementation of an ERAS protocol led in four of five comparative studies to a significant decrease in length of stay (reduction of 2–6 days in different studies). Meta-analysis of four studies focusing on PDs showed that there was a significant difference in complication rates in favor of the ERAS group (absolute risk difference 8.2 %, 95 % confidence interval (CI) 2.0–14.4, p = 0.008). Introduction of an ERAS protocol did not result in an increase in mortality or readmissions. Delayed gastric emptying and incidence of pancreatic fistula did not differ significantly between groups. All studies reporting on hospital costs showed a decrease after implementation of ERAS.

Conclusions

This systematic review suggests that using an ERAS protocol in pancreatic resections may help to shorten hospital length of stay without compromising morbidity and mortality. This seemed to apply to distal pancreatectomy, total pancreatectomy, and PD. Meta-analysis was performed for those studies focusing on PD and showed that there were no differences in readmission or mortality. Morbidity rates were significantly lower for patients managed according ERAS principles.