Expression of neurogenin3 reveals an islet cell precursor population in the pancreas

Differentiation of early gut endoderm cells into the endocrine cells forming the pancreatic islets of Langerhans depends on a cascade of gene activation events controlled by transcription factors including the basic helix-loop-helix (bHLH) proteins. To delineate this cascade, we began by establishing the position of neurogenin3, a bHLH factor found in the pancreas during fetal development. We detect neurogenin3 immunoreactivity transiently in scattered ductal cells in the fetal mouse pancreas, peaking at embryonic day 15.5. Although not detected in cells expressing islet hormones or the islet transcription factors Isl1, Brn4, Pax6 or PDX1, neurogenin3 is detected along with early islet differentiation factors Nkx6.1 and Nkx2.2, establishing that it is expressed in immature cells in the islet lineage. Analysis of transcription factor-deficient mice demonstrates that neurogenin3 expression is not dependent on neuroD1/BETA2, Mash1, Nkx2.2, Nkx6.1, or Pax6. Furthermore, early expression of neurogenin3 under control of the Pdx1 promoter is alone sufficient to drive early and ectopic differentiation of islet cells, a capability shared by the pancreatic bHLH factor, neuroD1/BETA2, but not by the muscle bHLH factor, MyoD. However, the islet cells produced in these transgenic experiments are overwhelmingly α cells, suggesting that factors other than the bHLH factors are required to deviate from a default α cell fate. These data support a model in which neurogenin3 acts upstream of other islet differentiation factors, initiating the differentiation of endocrine cells, but switching off prior to final differentiation. The ability to uniquely identify islet cell precursors by neurogenin3 expression allows us to determine the position of other islet transcription factors in the differentiation cascade and to propose a map for the islet cell differentiation pathway

Condition-dependence of Defensive Tail Displays in Common Garter Snakes (Thamnophis sirtalis)

Individual snakes can exhibit a diversity of antipredator responses including crypsis, flight, and a variety of stereotyped behavioral reactions to predators at close range. Among these responses are behavioral differences in the movement (e.g., waving or wiggling) of a conspicuous tail by an otherwise cryptically colored snake. Defensive tail displays may disorient a predator, divert attack to the tail, act as a warning signal, or serve no function at all. The use of tail displays in snakes may also depend on current physiological investment into color production and body size, which can affect locomotor ability to escape predators. The purpose of this study was to determine if variation in tail color is related to the defensive tail behavior exhibited in Common Garter Snakes (Thamnophis sirtalis) when subject to a sudden tactile stimulus. We also analyzed potential relationships between tail coloration, mass, and circulating concentrations of testosterone, to determine if conspicuous tail morphology is condition-dependent. Here, relative tail orange coverage is significantly related to defensive tail behavior and also yields significant negative correlations with mass and testosterone concentrations. This suggests conspicuous tail displays in T. sirtalis to be a size-dependent response to predation, as mediated by testosterone. The prevalence of this defensive behavior in relatively smaller snakes may function as a diversion of attack to the tail while larger snakes instead exhibit greater locomotor capacity to escape predation

Upright Birthing Positions: The Positive Impacts on Labor

The lithotomy position is the most common birthing position currently used in Western medicine. Historically, women used upright birthing positions which include sitting, kneeling, squatting, and standing. This article reviews the advantages of upright birthing positions in comparison to lithotomy. Studies have shown benefits in reduced episiotomies, perineal trauma, and labor time, while providing the most optimal pelvic position

In newborn babies, what are the risks of developing Vitamin K deficiency bleeding disorders if not provided IM Vitamin K injection at birth?

Vitamin K, which is produced in the large intestines of adults, is naturally lacking in neonates. It is a crucial part in the clotting cascade for activating clotting factors II, VII, IX, and X. For the past several decades, it has been a standard in Western Medicine to give an IM Vitamin K injection to neonates post birth. In recent years, statistics of refusal have continued to grow creating an increased prevalence of Vitamin K Deficiency Bleeding Disorders. This study is aimed at exploring the statistics of injection refusal, reasons for refusal, alternative methods to injections, and the importance behind parent education. The studies analyzed demonstrate that there are higher rates of refusal in birth centers and home births as opposed to hospital births. Alternative methods studied, such as breast feeding and mother supplementation, have not been shown to be an equivalent to the IM injection, however, there is promising research regarding an oral method of Vitamin K administration. Based on the research conducted, it is imperative that providers ensure proper patient education throughout the entire pregnancy regarding screenings and preventions, such as a Vitamin K injection and what it prevents, so that parents can make informed decisions when their child is born

RNA-Seq analysis of seasonal and individual variation in blood transcriptomes of healthy managed bottlenose dolphins

All globin depleted samples and associated physical or hematological parameters measured. (XLS 43 kb

Rosetta-Alice Observations of Exospheric Hydrogen and Oxygen on Mars

The European Space Agency's Rosetta spacecraft, en route to a 2014 encounter with comet 67P/Churyumov-Gerasimenko, made a gravity assist swing-by of Mars on 25 February 2007, closest approach being at 01:54UT. The Alice instrument on board Rosetta, a lightweight far-ultraviolet imaging spectrograph optimized for in situ cometary spectroscopy in the 750-2000 A spectral band, was used to study the daytime Mars upper atmosphere including emissions from exospheric hydrogen and oxygen. Offset pointing, obtained five hours before closest approach, enabled us to detect and map the HI Lyman-alpha and Lyman-beta emissions from exospheric hydrogen out beyond 30,000 km from the planet's center. These data are fit with a Chamberlain exospheric model from which we derive the hydrogen density at the 200 km exobase and the H escape flux. The results are comparable to those found from the the Ultraviolet Spectrometer experiment on the Mariner 6 and 7 fly-bys of Mars in 1969. Atomic oxygen emission at 1304 A is detected at altitudes of 400 to 1000 km above the limb during limb scans shortly after closest approach. However, the derived oxygen scale height is not consistent with recent models of oxygen escape based on the production of suprathermal oxygen atoms by the dissociative recombination of O2+.Comment: 17 pages, 8 figures, accepted for publication in Icaru

More salt, please:global patterns, responses, and impacts of foliar sodium in grasslands

Sodium is unique among abundant elemental nutrients, because most plant species do not require it for growth or development, whereas animals physiologically require sodium. Foliar sodium influences consumption rates by animals and can structure herbivores across landscapes. We quantified foliar sodium in 201 locally abundant, herbaceous species representing 32 families and, at 26 sites on four continents, experimentally manipulated vertebrate herbivores and elemental nutrients to determine their effect on foliar sodium. Foliar sodium varied taxonomically and geographically, spanning five orders of magnitude. Site‐level foliar sodium increased most strongly with site aridity and soil sodium; nutrient addition weakened the relationship between aridity and mean foliar sodium. Within sites, high sodium plants declined in abundance with fertilisation, whereas low sodium plants increased. Herbivory provided an explanation: herbivores selectively reduced high nutrient, high sodium plants. Thus, interactions among climate, nutrients and the resulting nutritional value for herbivores determine foliar sodium biogeography in herbaceous‐dominated systems

First Case Start Times for Vascular Surgery

Problem/Impact Statement: 85% of first cases at Maine Medical Center for Vascular Surgery start late. According to one study done by Aurora Health Care; of 5,500 first case surgeries, 88% of them started late. The impact of this is far reaching. It is not in alignment with MMC value of Patient Centered Care because the patient becomes dissatisfied waiting to be brought in to surgery , they are fasting for longer than anticipated, and being away from their family while they wait causing anxiety. The financial impact is $1995 for each 1⁄2 hr. of O.R. time. Furthermore, this may result in elective cases being canceled, late cases create a back log of cases to be done, the hospital loses potential revenue, and staff stay later causing overtime accrual