Routine repeat head CT may not be necessary for patients with mild TBI.

Background:Routine repeat cranial CT (RHCT) is standard of care for CT-verified traumatic brain injury (TBI). Despite mixed evidence, those with mild TBI are subject to radiation and expense from serial CT scans. Thus, we investigated the necessity and utility of RHCT for patients with mild TBI. We hypothesized that repeat head CT in these patients would not alter patient care or outcomes. Methods:We retrospectively studied patients suffering from mild TBI (Glasgow Coma Scale (GCS) score 13-15) and treated at the R Adams Cowley Shock Trauma Center from November 2014 through January 2015. The primary outcome was the need for surgical intervention. Outcomes were compared using paired Student's t-test, and stratified by injury on initial CT, GCS change, demographics, and presenting vital signs (mean ± SD). Results:Eighty-five patients met inclusion criteria with an average initial GCS score=14.6±0.57. Our center sees about 2800 patients with TBI per year, or about 230 per month. This includes patients with concussions. This sample represents about 30% of patients with TBI seen during the study period. Ten patients required operation (four based on initial CT and others for worsening GCS, headaches, large unresolving injury). There was progression of injury on repeat CT scan in only two patients that required operation, and this accompanied clinical deterioration. The mean brain Abbreviated Injury Scale (AIS) score was 4.8±0.3 for surgical patients on initial CT scan compared with 3.4±0.6 (P<0.001) for non-surgical patients. Initial CT subdural hematoma size was 1.1±0.6 cm for surgical patients compared with 0.49±0.3 cm (P=0.05) for non-surgical patients. There was no significant difference between intervention groups in terms of other intracranial injuries, demographics, vital signs, or change in GCS. Overall, 75 patients that did not require surgical intervention received RHCT. At $340 per CT,$51 000 was spent on unnecessary imaging ($367 000/year, extrapolated). Discussion:In an environment of increased scrutiny on healthcare expenditures, it is necessary to question dogma and eliminate unnecessary cost. Our data questions the use of routine repeat head CT scans in every patient with anatomic TBI and suggests that clinically stable patients with small injury can simply be followed clinically. Level of evidence:Level III

Experimental Studies in Stereolithography Resolution

As we move towards micron-scale rapid manufacturing, it is critical to understand build resolution of Stereolithography technology. In order to determine the resolution limitations, positive and negative features on Stereolithography parts were built and analyzed. Results from several experiments were compared to an analytical model and important resolution issues are highlighted. Based on these experimental results, parameters that will maximize build resolution for a number of well-understood shapes are suggested in the paper. Build resolution experimental results, analysis, and measurement techniques are discussed. Conclusions are drawn related to feature shape as resolution limits are approached.We gratefully acknowledge the support from the RPMI member companies and the George W. Woodruff School of Mechanical Engineering at Georgia Tech. This work was partially funded by the National Science Foundation under Grant Number DMI-9988664.Mechanical Engineerin

Risk factors for Barrett’s esophagus among patients with gastroesophageal reflux disease: A community clinic-based case-control study

Objective: To measure the relative risks of Barrett’s esophagus (BE) associated with demographic factors, measures of adiposity and smoking among patients with gastroesophageal reflux disease (GERD). Methods: Patients newly diagnosed with specialized intestinal metaplasia (SIM) (n=197) were compared to patients with GERD (n= 418) in a community clinic-based case-control study. Case sub-groups included those with any visible columnar epithelium (VBE) (n=97), and those with a long segment (=2cm) of columnar epithelium (LSBE) (n=54). Results: Risks increased with older age (adjusted odds ratio (aOR) per decade for SIM=1.3, 95% confidence interval (CI)= 1.1-1.5; VBE aOR=1.4 ,CI=1.1-1.6; LSBE aOR=1.5, CI=1.2-1.9), male gender (SIM aOR=1.5, CI=1.1-2.2; VBE aOR=2.7, CI=1.6-4.5; LSBE aOR=3.9, CI=1.9- 8.1) and possibly Asian race. Increased risk of BE in particular was observed with high waist-tohip ratio (WHR, male high: =0.9, female high: =0.8) (SIM aOR=1.3, CI=0.9-2.1; VBE aOR=1.9, CI=1.0-3.5; LSBE aOR=4.1, CI=1.5-11.4). These associations were independent of body mass index (BMI) for the VBE and LSBE case groups but not for SIM which was the only case group in which BMI was a significant risk factor. Ever smoking cigarettes increased risk similarly for all case groups (SIM aOR=1.8, CI=1.2-2.6; VBE aOR=1.6, CI=1.0-2.6; LSBE aOR=2.6, CI=1.3- 4.9), although dose response relationship was not detected for duration or intensity of smoking. Conclusions: Older age, male gender and history of smoking increased risk of SIM and BE among GERD patients independent of other risk factors for BE. Central adiposity was most strongly related to risk of VBE and LSBE. These results may be useful in development of risk profiles for screening GERD patients

Report of the panel on earth rotation and reference frames, section 7

Objectives and requirements for Earth rotation and reference frame studies in the 1990s are discussed. The objectives are to observe and understand interactions of air and water with the rotational dynamics of the Earth, the effects of the Earth's crust and mantle on the dynamics and excitation of Earth rotation variations over time scales of hours to centuries, and the effects of the Earth's core on the rotational dynamics and the excitation of Earth rotation variations over time scales of a year or longer. Another objective is to establish, refine and maintain terrestrial and celestrial reference frames. Requirements include improvements in observations and analysis, improvements in celestial and terrestrial reference frames and reference frame connections, and improved observations of crustal motion and mass redistribution on the Earth

Brain weight differences associated with induced focal microgyria

BACKGROUND: Disrupting neural migration with bilateral focal freezing necrosis on postnatal day 1 (P1) results in the formation of 4-layered microgyria. This developmental injury triggers a pervasive neural reorganization, which is evident at the electrophysiological, behavioral, and anatomical levels. In this experiment, we investigated changes in brain weight as an index of global disruption of neural systems caused by focal damage to the developing cortical plate. RESULTS: We found a dramatic reduction in overall brain weight in microgyric subjects. This reduction in brain weight among animals with microgyria is reflected in decreased total brain volume, with a disproportionate decrease in neocortical volume. This effect is so robust that it is seen across varied environments, at variable ages, and across the sexes. CONCLUSIONS: This finding supports previous work suggesting that substantial reorganization of the brain is triggered by the induction of bilateral freezing damage. These results have critical implications for the profound re-organizational effects of relatively small focal injuries early in development to distributed systems throughout the brain, and particularly in the cerebral cortex

Motor recovery and cortical reorganization after constraint-induced movement therapy in stroke patients: a preliminary study.

Constraint-induced movement therapy (CIMT) is a physical rehabilitation regime that has been previously shown to improve motor function in chronic hemiparetic stroke patients. However, the neural mechanisms supporting rehabilitation-induced motor recovery are poorly understood. The goal of this study was to assess motor cortical reorganization after CIMT using functional magnetic resonance imaging (fMRI). In a repeated-measures design, 4 incompletely recovered chronic stroke patients treated with CIMT underwent motor function testing and fMRI. Five age-matched normal subjects were also imaged. A laterality index (LI) was determined from the fMRI data, reflecting the distribution of activation in motor cortices contralateral compared with ipsilateral to the moving hand. Pre-intervention fMRI showed a lower LI during affected hand movement of stroke patients (LI = 0.23+/-0.07) compared to controls (LI unaffected patient hand = 0.65+/-0.10; LI dominant normal hand = 0.65+/-0.11; LI nondominant normal hand = 0.69+/-0.11; P < 0.05) due to trends toward increased ipsilateral motor cortical activation. Motor function testing showed that patients made significant gains in functional use of the stroke-affected upper extremity (detected by the Motor Activity Log) and significant reductions in motor impairment (detected by the Fugl-Meyer Stroke Scale and the Wolf Motor Function Test) immediately after CIMT, and these effects persisted at 6-month follow-up. The behavioral effects of CIMT were associated with a trend toward a reduced LI from pre-intervention to immediately post-intervention (LI = -0.01+/-0.06, P = 0.077) and 6 months post-intervention (LI = -0.03+/-0.15). Stroke-affected hand movement was not accompanied by mirror movements during fMRI, and electromyographic measures of mirror recruitment under simulated fMRI conditions were not correlated with LI values. These data provide preliminary evidence that gains in motor function produced by CIMT in chronic stroke patients may be associated with a shift in laterality of motor cortical activation toward the undamaged hemisphere

Genetic Markers of IgG Influence The Outcome of Infection with Hepatitis C Virus

We examined the role that immunoglobulin GM and KM allotypes—genetic markers of γ and κ chains, respectively—play in the outcome of hepatitis C virus (HCV) infection in white Americans. A total of 119 persons who had cleared HCV and 111 with persistent HCV infection were genotyped for the presence of several GM and KM determinants. Persistent HCV infection was more than three times as likely (odds ratio, 3.50; P = .01) in subjects who were carriers of the GM3 allele than in those who were noncarriers. These results show that particular GM alleles may be important determinants of the outcome of HCV infection

The gut microbiota of people with asthma influences lung inflammation in gnotobiotic mice

The gut microbiota in early childhood is linked to asthma risk, but may continue to affect older patients with asthma. Here, we profile the gut microbiota of 38 children (19 asthma, median age 8) and 57 adults (17 asthma, median age 28) by 16S rRNA sequencing and find individuals with asthma harbored compositional differences from healthy controls in both adults and children. We develop a model to aid the design of mechanistic experiments in gnotobiotic mice and show enterotoxigeni