Cold Weather Injury in a Special Operations Aviation Crew Member: A Case Report.

As arctic warfare becomes a center focus within Special Operations, cold weather injury looms as both a medical and operational threat. While cold weather injury can range from pernio to hemodynamically unstable systemic hypothermia, the more minor injuries are far more common. However, these present a challenge in austere medical care and can drastically impact mission capability. We present a case of a Special Operations crew chief with cold weather digital injury while at the Arctic Isolation Course in Alaska and his subsequent clinical course. Prevention remains the key for mitigating these injuries, while the decision to rewarm must be made with both medical and tactical factors in mind as refreezing incurs significant morbidity. Other components of prehospital treatment include active rewarming, ibuprofen, aloe vera, and pain control.

PIWI-mediated control of tissue-specific transposons is essential for somatic cell differentiation.

PIWI proteins are known as mediators of transposon silencing in animal germlines but are also found in adult pluripotent stem cells of highly regenerative animals, where they are essential for regeneration. Study of the nuclear PIWI protein SMEDWI-2 in the planarian somatic stem cell system reveals an intricate interplay between transposons and cell differentiation in which a subset of transposons is inevitably activated during cell differentiation, and the PIWI protein is required to regain control. Absence of SMEDWI-2 leads to tissue-specific transposon derepression related to cell-type-specific chromatin remodeling events and in addition causes reduced accessibility of lineage-specific genes and defective cell differentiation, resulting in fatal tissue dysfunction. Finally, we show that additional PIWI proteins provide a stem-cell-specific second layer of protection in planarian neoblasts. These findings reveal a far-reaching role of PIWI proteins and PIWI-interacting RNAs (piRNAs) in stem cell biology and cell differentiation.

New Versus Old, The i-View Video Laryngoscope Versus the GlideScope: A Prospective, Randomized, Crossover Trial.

BACKGROUND: A novel video laryngoscope device, the i-view, may extend intubation capability to the lowest echelons of deployed military medicine. The i-view is a one-time use, disposable laryngoscope. We compared time to completion of endotracheal intubation (ETI) between the i-view and GlideScope among military emergency medicine providers in a simulation setting. METHODS: We conducted a prospective, randomized, crossover trial. We randomized participants to i-view or GlideScope first before they performed 2 ETI-1 with each device. The primary outcome was time to completion of ETI. Secondary outcomes included first-pass success, optimal glottic view, and end-user appraisal. We used a Laerdal Airway Management Trainer for all intubations. RESULTS: Thirty-three emergency medicine providers participated. ETI time was less with GlideScope than i-view (22.2 +/- 9.0 seconds versus 30.2 +/- 24.0 seconds; p=0.048). Optimal glottic views, using the Cormack-Lehan scale, also favored the GlideScope (2 [1,2] versus 2[2,2]; p=0.044). There was no difference in first-pass success rates (100% versus 100%). More participants preferred the GlideScope (24 versus 9; p=0.165); however, participants agreed that the i-view would be easier to use than the GlideScope in an austere environment (4[4,5]). CONCLUSIONS: We found the GlideScope outperformed the i-view with respect to procedural completion time. Participants preferred the GlideScope over i-view, but indicated the i-view would be easier to use than the GlideScope in an austere setting. Our findings suggest the i-view may be a suitable alternative to GlideScope for US military providers, especially for those in the prehospital setting.

Imprinted DNA methylation reconstituted at a non-imprinted locus.

BACKGROUND: In mammals, tight regulation of cytosine methylation is required for embryonic development and cellular differentiation. The trans-acting DNA methyltransferases that catalyze this modification have been identified and characterized; however, these proteins lack sequence specificity, leaving the mechanism of targeting unknown. A cis-acting regulator within the Rasgrf1 imprinting control region (ICR) is necessary for establishment and maintenance of local imprinted methylation. Here, we investigate whether 3-kb of sequence from the Rasgrf1 ICR is sufficient to direct appropriate imprinted methylation and target gene expression patterns when ectopically inserted at the Wnt1 locus. RESULTS: The Rasgrf1 ICR at Wnt1 lacked somatic methylation when maternally transmitted and was fully methylated upon paternal transmission, consistent with its behavior at the Rasgrf1 locus. It was unmethylated in the female germline and was enriched for methylation in the male germline, though not to the levels seen at the endogenous Rasgrf1 allele. Wnt1 expression was not imprinted by the ectopic ICR, likely due to additional sequences being required for this function. CONCLUSIONS: We have identified sequences that are sufficient for partial establishment and full maintenance of the imprinted DNA methylation patterns. Because full somatic methylation can occur without full gametic methylation, we infer that somatic methylation of the Rasgrf1 ICR is not simply a consequence of maintained gametic methylation.

Long non-coding RNA regulation of reproduction and development.

Noncoding RNAs (ncRNAs) have long been known to play vital roles in eukaryotic gene regulation. Studies conducted over a decade ago revealed that maturation of spliced, polyadenylated coding mRNA occurs by reactions involving small nuclear RNAs and small nucleolar RNAs; mRNA translation depends on activities mediated by transfer RNAs and ribosomal RNAs, subject to negative regulation by micro RNAs; transcriptional competence of sex chromosomes and some imprinted genes is regulated in cis by ncRNAs that vary by species; and both small-interfering RNAs and piwi-interacting RNAs bound to Argonaute-family proteins regulate post-translational modifications on chromatin and local gene expression states. More recently, gene-regulating noncoding RNAs have been identified, such as long intergenic and long noncoding RNAs (collectively referred to as lncRNAs)--a class totaling more than 100,000 transcripts in humans, which include some of the previously mentioned RNAs that regulate dosage compensation and imprinted gene expression. Here, we provide an overview of lncRNA activities, and then review the role of lncRNAs in processes vital to reproduction, such as germ cell specification, sex determination and gonadogenesis, sex hormone responses, meiosis, gametogenesis, placentation, non-genetic inheritance, and pathologies affecting reproductive tissues. Results from many species are presented to illustrate the evolutionarily conserved processes lncRNAs are involved in.

Contrast-enhanced bolus-chased whole-body MR angiography using a moving tabletop and quadrature body coil acquisition.

OBJECTIVE: MR angiography is now an established technique for the evaluation of various arterial structures. With recent developments in hardware, whole-body imaging has become technically feasible. The aim of this study is to describe a technique for whole-body MR angiography using a quadrature body coil and a moving tabletop. CONCLUSION: Whole-body MR angiography is technically feasible and may offer a method of screening for unsuspected disease.