Performance of the Sellick maneuver significantly improves when residents and trained nurses use a visually interactive guidance device in simulation.

We examined the proper performance of the Sellick maneuver, a maneuver used to reduce the risk of aspiration of stomach contents during induction of general anesthesia, using a novel device that measures and visualizes the force applied to the cricoid cartilage using thin-film force sensitive resistors in a form suitable for in vivo use. Performance was tested in three stages with twenty anaesthesiology residents and twenty trained operating room nurses. Firstly, subjects applied force to the cricoid cartilage as was customary to them. Secondly, subjects used the device to guide the application of that force. Thirdly, subjects were again asked to perform the manoeuvre without visual guidance. Each test lasted 1 min and the amount of force applied was measured throughout. Overall, the Sellick maneuver was often not applied properly, with large variance between individual subjects. Performance and inter-subject consistency improved to a very highly significant degree when subjects were able to use the device as a visual guide (p < 0.001). Subsequent significant improvements in performances during the last, unguided test demonstrated that the device initiated learning.

FMRP regulates the transition from radial glial cells to intermediate progenitor cells during neocortical development.

During vertebrate cortical neurogenesis, radial glial cells (RGCs) serve as neural stem cells that generate neurons directly or indirectly through intermediate progenitor cells (IPCs). The transition from RGCs to IPCs is a key step in determining overall neuronal production and may underlie evolutionary expansion of the cerebral cortex. Here we show that this transition is controlled by fragile X mental retardation protein (FMRP), an RNA-binding protein whose deficiency causes fragile X syndrome. Analysis of mouse embryos electroporated with FMRP small hairpin RNA and knock-out mouse embryos lacking FMRP reveals that specific loss of FMRP causes depletion of neocortical RGCs due to an RGC-to-IPC cell fate change. The RGC depletion is associated with altered F-actin organization and can be largely rescued by overexpressing profilin 1 (Pfn1), a core actin regulatory protein promoting F-actin formation. Our data suggest that FMRP suppresses the transition from RGCs to IPCs during neocortical development by an actin-dependent mechanism.

Inclusion body formation and neurodegeneration are parkin independent in a mouse model of alpha-synucleinopathy.

Mutations in the genes coding for alpha-synuclein and parkin cause autosomal-dominant and autosomal-recessive forms of Parkinson's disease (PD), respectively. Alpha-synuclein is a major component of Lewy bodies, the proteinaceous cytoplasmic inclusions that are the pathological hallmark of idiopathic PD. Lewy bodies appear to be absent in cases of familial PD associated with mutated forms of parkin. Parkin is an ubiquitin E3 ligase, and it may be involved in the processing and/or degradation of alpha-synuclein, as well as in the formation of Lewy bodies. Here we report the behavioral, biochemical, and histochemical characterization of double-mutant mice overexpressing mutant human A53T alpha-synuclein on a parkin null background. We find that the absence of parkin does not have an impact on the onset and progression of the lethal phenotype induced by overexpression of human A53T alpha-synuclein. Furthermore, all major behavioral, biochemical, and morphological characteristics of A53T alpha-synuclein-overexpressing mice are not altered in parkin null alpha-synuclein-overexpressing double-mutant mice. Our results demonstrate that mutant alpha-synuclein induces neurodegeneration independent of parkin-mediated ubiquitin E3 ligase activity in nondopaminergic systems and suggest that PD caused by alpha-synuclein and parkin mutations may occur via independent mechanisms.

Accumulation of the authentic parkin substrate aminoacyl-tRNA synthetase cofactor, p38/JTV-1, leads to catecholaminergic cell death.

Autosomal-recessive juvenile parkinsonism (AR-JP) is caused by loss-of-function mutations of the parkin gene. Parkin, a RING-type E3 ubiquitin ligase, is responsible for the ubiquitination and degradation of substrate proteins that are important in the survival of dopamine neurons in Parkinson's disease (PD). Accordingly, the abnormal accumulation of neurotoxic parkin substrates attributable to loss of parkin function may be the cause of neurodegeneration in parkin-related parkinsonism. We evaluated the known parkin substrates identified to date in parkin null mice to determine whether the absence of parkin results in accumulation of these substrates. Here we show that only the aminoacyl-tRNA synthetase cofactor p38 is upregulated in the ventral midbrain/hindbrain of both young and old parkin null mice. Consistent with upregulation in parkin knock-out mice, brains of AR-JP and idiopathic PD and diffuse Lewy body disease also exhibit increased level of p38. In addition, p38 interacts with parkin and parkin ubiquitinates and targets p38 for degradation. Furthermore, overexpression of p38 induces cell death that increases with tumor necrosis factor-alpha treatment and parkin blocks the pro-cell death effect of p38, whereas the R42P, familial-linked mutant of parkin, fails to rescue cell death. We further show that adenovirus-mediated overexpression of p38 in the substantia nigra in mice leads to loss of dopaminergic neurons. Together, our study represents a major advance in our understanding of parkin function, because it clearly identifies p38 as an important authentic pathophysiologic substrate of parkin. Moreover, these results have important implications for understanding the molecular mechanisms of neurodegeneration in PD.

Microbial survival of space vacuum and extreme ultraviolet irradiation: strain isolation and analysis during a rocket flight.

We have recovered new isolates from hot springs, in Yellowstone National Park and the Kamchatka Peninsula, after gamma-irradiation and exposure to high vacuum (10(-6) Pa) of the water and sediment samples. The resistance to desiccation and ionizing radiation of one of the isolates, Bacillus sp. strain PS3D, was compared to that of the mesophilic bacterium, Deinococcus radiodurans, a species well known for its extraordinary resistance to desiccation and high doses of ionizing radiation. Survival of these two microorganisms was determined in real and simulated space conditions, including exposure to extreme UV radiation (10-100 nm) during a rocket flight. We found that up to 15 days of desiccation alone had little effect on the viability of either bacterium. In contrast, exposure to space vacuum ( approximately 10(-6) Pa) decreased cell survival by two and four orders of magnitude for Bacillus sp. strain PS3D and D. radiodurans, respectively. Simultaneous exposure to space vacuum and extreme UV radiation further decreased the survival of both organisms, compared to unirradiated controls. This is the first report on the isolated effect of extreme UV at 30 nm on cell survival. Extreme UV can only be transmitted through high vacuum, therefore its penetration into the cells may only be superficial, suggesting that in contrast to near UV, membrane proteins rather than DNA were damaged by the radiation.