The Opioid Analgesic Reduction Study (OARS) Pilot: A Double-Blind Randomized Multicenter Trial.

BACKGROUND: With addiction rates and opioid deaths increasing, health care providers are obligated to help stem the opioid crisis. As limited studies examine the comparative effectiveness of fixed-dose combination nonopioid analgesia to opioid-containing analgesia, a comparative effectiveness study was planned and refined by conducting a pilot study. METHODS: The Opioid Analgesic Reduction Study (OARS) pilot, a stratified, randomized, multisite, double-blind clinical trial, was designed to test technology and procedures to be used in the full OARS trial. Participants engaged in the full protocol, enabling the collection of OARS outcome data. Eligible participants reporting to 1 of 5 sites for partial or full bony impacted mandibular third molar extraction were stratified by biologic sex and randomized to 1 of 2 treatment groups, OPIOID or NONOPIOID. OPIOID participants were provided 20 doses of hydrocodone 5 mg/acetaminophen 300 mg. NONOPIOID participants were provided 20 doses of ibuprofen 400 mg/acetaminophen 500 mg. OARS outcomes data, including pain experience, adverse effects, sleep quality, pain interference, overall satisfaction, and remaining opioid tablets available for diversion, were collected via surveys, electronic medication bottles, eDiary, and activity/sleep monitor. RESULTS: Fifty-three participants were randomized with 50 completing the OARS pilot protocol. Across all outcome pain domains, in all but 1 time period, NONOPIOID was better in managing pain than OPIOID (P < 0.05 level). Other outcomes suggest less pain interference, less adverse events, better sleep quality, better overall satisfaction, and fewer opioid-containing tablets available for diversion. DISCUSSION: Results suggest patients requiring impacted mandibular third molar extraction would benefit from fixed-dose combination nonopioid analgesia. KNOWLEDGE TRANSFER STATEMENT: Study results suggest fixed-dose nonopioid combination ibuprofen 400 mg/acetaminophen 500 mg is superior to opioid-containing analgesic (hydrocodone 5 mg/acetaminophen 500 mg). This knowledge should inform surgeons and patients in the selection of postsurgical analgesia.

A distinct isoform of lymphoid enhancer binding factor 1 (LEF1) epigenetically restricts EBV reactivation to maintain viral latency.

As a human tumor virus, EBV is present as a latent infection in its associated malignancies where genetic and epigenetic changes have been shown to impede cellular differentiation and viral reactivation. We reported previously that levels of the Wnt signaling effector, lymphoid enhancer binding factor 1 (LEF1) increased following EBV epithelial infection and an epigenetic reprogramming event was maintained even after loss of the viral genome. Elevated LEF1 levels are also observed in nasopharyngeal carcinoma and Burkitt lymphoma. To determine the role played by LEF1 in the EBV life cycle, we used in silico analysis of EBV type 1 and 2 genomes to identify over 20 Wnt-response elements, which suggests that LEF1 may bind directly to the EBV genome and regulate the viral life cycle. Using CUT&RUN-seq, LEF1 was shown to bind the latent EBV genome at various sites encoding viral lytic products that included the immediate early transactivator BZLF1 and viral primase BSLF1 genes. The LEF1 gene encodes various long and short protein isoforms. siRNA depletion of specific LEF1 isoforms revealed that the alternative-promoter derived isoform with an N-terminal truncation (ΔN LEF1) transcriptionally repressed lytic genes associated with LEF1 binding. In addition, forced expression of the ΔN LEF1 isoform antagonized EBV reactivation. As LEF1 repression requires histone deacetylase activity through either recruitment of or direct intrinsic histone deacetylase activity, siRNA depletion of LEF1 resulted in increased histone 3 lysine 9 and lysine 27 acetylation at LEF1 binding sites and across the EBV genome. Taken together, these results indicate a novel role for LEF1 in maintaining EBV latency and restriction viral reactivation via repressive chromatin remodeling of critical lytic cycle factors.

Retinoblastoma Protein Is Required for Epstein-Barr Virus Replication in Differentiated Epithelia.

Coinfection of human papillomavirus (HPV) and Epstein-Barr virus (EBV) has been detected in oropharyngeal squamous cell carcinoma. Although HPV and EBV replicate in differentiated epithelial cells, we previously reported that HPV epithelial immortalization reduces EBV replication within organotypic raft culture and that the HPV16 oncoprotein E7 was sufficient to inhibit EBV replication. A well-established function of HPV E7 is the degradation of the retinoblastoma (Rb) family of pocket proteins (pRb, p107, and p130). Here, we show that pRb knockdown in differentiated epithelia and EBV-positive Burkitt lymphoma (BL) reduces EBV lytic replication following de novo infection and reactivation, respectively. In differentiated epithelia, EBV immediate early (IE) transactivators were expressed, but loss of pRb blocked expression of the early gene product, EA-D. Although no alterations were observed in markers of epithelial differentiation, DNA damage, and p16, increased markers of S-phase progression and altered p107 and p130 levels were observed in suprabasal keratinocytes after pRb knockdown. In contrast, pRb interference in Akata BX1 Burkitt lymphoma cells showed a distinct phenotype from differentiated epithelia with no significant effect on EBV IE or EA-D expression. Instead, pRb knockdown reduced the levels of the plasmablast differentiation marker PRDM1/Blimp1 and increased the abundance of c-Myc protein in reactivated Akata BL with pRb knockdown. c-Myc RNA levels also increased following the loss of pRb in epithelial rafts. These results suggest that pRb is required to suppress c-Myc for efficient EBV replication in BL cells and identifies a mechanism for how HPV immortalization, through degradation of the retinoblastoma pocket proteins, interferes with EBV replication in coinfected epithelia. IMPORTANCE Terminally differentiated epithelium is known to support EBV genome amplification and virion morphogenesis following infection. The contribution of the cell cycle in differentiated tissues to efficient EBV replication is not understood. Using organotypic epithelial raft cultures and genetic interference, we can identify factors required for EBV replication in quiescent cells. Here, we phenocopied HPV16 E7 inhibition of EBV replication through knockdown of pRb. Loss of pRb was found to reduce EBV early gene expression and viral replication. Interruption of the viral life cycle was accompanied by increased S-phase gene expression in postmitotic keratinocytes, a process also observed in E7-positive epithelia, and deregulation of other pocket proteins. Together, these findings provide evidence of a global requirement for pRb in EBV lytic replication and provide a mechanistic framework for how HPV E7 may facilitate a latent EBV infection through its mediated degradation of pRb in copositive epithelia.

EBV Association with Lymphomas and Carcinomas in the Oral Compartment.

Epstein-Barr virus (EBV) is an oncogenic human herpesvirus infecting approximately 90% of the world's population. The oral cavity serves a central role in the life cycle, transmission, and pathogenesis of EBV. Transmitted to a new host via saliva, EBV circulates between cellular compartments within oral lymphoid tissues. Epithelial cells primarily support productive viral replication, while B lymphocytes support viral latency and reactivation. EBV infections are typically asymptomatic and benign; however, the latent virus is associated with multiple lymphomas and carcinomas arising in the oral cavity. EBV association with cancer is complex as histologically similar cancers often test negative for the virus. However, the presence of EBV is associated with distinct features in certain cancers. The intrinsic ability of EBV to immortalize B-lymphocytes, via manipulation of survival and growth signaling, further implicates the virus as an oncogenic cofactor. A distinct mutational profile and burden have been observed in EBV-positive compared to EBV-negative tumors, suggesting that viral infection can drive alternative pathways that converge on oncogenesis. Taken together, EBV is also an important prognostic biomarker that can direct alternative therapeutic approaches. Here, we discuss the prevalence of EBV in oral malignancies and the EBV-dependent mechanisms associated with tumorigenesis.

Nitrogen and Iron Availability Drive Metabolic Remodeling and Natural Selection of Diverse Phytoplankton during Experimental Upwelling.

Nearly half of carbon fixation and primary production originates from marine phytoplankton, and much of it occurs in episodic blooms in upwelling regimes. Here, we simulated blooms limited by nitrogen and iron by incubating Monterey Bay surface waters with subnutricline waters and inorganic nutrients and measured the whole-community transcriptomic response during mid- and late-bloom conditions. Cell counts revealed that centric and pennate diatoms (largely Pseudo-nitzschia and Chaetoceros spp.) were the major blooming taxa, but dinoflagellates, prasinophytes, and prymnesiophytes also increased. Viral mRNA significantly increased in late bloom and likely played a role in the bloom's demise. We observed conserved shifts in the genetic similarity of phytoplankton populations to cultivated strains, indicating adaptive population-level changes in community composition. Additionally, the density of single nucleotide variants (SNVs) declined in late-bloom samples for most taxa, indicating a loss of intraspecific diversity as a result of competition and a selective sweep of adaptive alleles. We noted differences between mid- and late-bloom metabolism and differential regulation of light-harvesting complexes (LHCs) under nutrient stress. While most LHCs are diminished under nutrient stress, we showed that diverse taxa upregulated specialized, energy-dissipating LHCs in low iron. We also suggest the relative expression of NRT2 compared to the expression of GSII as a marker of cellular nitrogen status and the relative expression of iron starvation-induced protein genes (ISIP1, ISIP2, and ISIP3) compared to the expression of the thiamine biosynthesis gene (thiC) as a marker of iron status in natural diatom communities. IMPORTANCE Iron and nitrogen are the nutrients that most commonly limit phytoplankton growth in the world's oceans. The utilization of these resources by phytoplankton sets the biomass available to marine systems and is of particular interest in high-nutrient, low-chlorophyll (HNLC) coastal fisheries. Previous research has described the biogeography of phytoplankton in HNLC regions and the transcriptional responses of representative taxa to nutrient limitation. However, the differential transcriptional responses of whole phytoplankton communities to iron and nitrogen limitation has not been previously described, nor has the selective pressure that these competitive bloom environments exert on major players. In addition to describing changes in the physiology of diverse phytoplankton, we suggest practical indicators of cellular nitrogen and iron status for future monitoring.

Qualitative evaluation of paediatric surgical otolaryngology content on YouTube.

OBJECTIVE: This study evaluated the quality of YouTube content focusing on common paediatric otolaryngology procedures, as this content can influence the opinions and medical decisions of patients. METHODS: A total of 120 YouTube videos were compiled to review using the terms 'adenoid removal', 'adenoidectomy', 'ear tubes', 'tympanostomy', 'tonsil removal' and 'tonsillectomy'. The Discern criteria was used to rate the quality of health information presented in each video. RESULTS: The mean bias Discern score was 3.18 and the mean overall Discern score was 2.39. Videos including US board certified physicians were rated significantly higher (p < 0.001) than videos without (bias Discern score = 3.00 vs 2.38; overall Discern score = 3.79 vs 1.55). The videos had been viewed a total of 176 769 549 times. CONCLUSION: Unbiased, high quality videos on YouTube are lacking. As patients may rely on this information when making medical decisions, it is important that practitioners continually evaluate and improve this video content. Otolaryngologists should be prepared to discuss YouTube content with patients.

Brain tumors disrupt the resting-state connectome.

Brain tumor patients often experience functional deficits that extend beyond the tumor site. While resting-state functional MRI (rsfMRI) has been used to map such functional connectivity changes in brain tumor patients, the interplay between abnormal tumor vasculature and the rsfMRI signal is still not well understood. Therefore, there is an exigent need for new tools to elucidate how the blood­oxygenation-level-dependent (BOLD) rsfMRI signal is modulated in brain cancer. In this initial study, we explore the utility of a preclinical model for quantifying brain tumor-induced changes on the rsfMRI signal and resting-state brain connectivity. We demonstrate that brain tumors induce brain-wide alterations of resting-state networks that extend to the contralateral hemisphere, accompanied by global attenuation of the rsfMRI signal. Preliminary histology suggests that some of these alterations in brain connectivity may be attributable to tumor-related remodeling of the neurovasculature. Moreover, this work recapitulates clinical rsfMRI findings from brain tumor patients in terms of the effects of tumor size on the neurovascular microenvironment. Collectively, these results lay the foundation of a preclinical platform for exploring the usefulness of rsfMRI as a potential new biomarker in patients with brain cancer.

IRS2 mutations linked to invasion in pleomorphic invasive lobular carcinoma.

Pleomorphic invasive lobular carcinoma (PILC) is an aggressive variant of invasive lobular breast cancer that is associated with poor clinical outcomes. Limited molecular data are available to explain the mechanistic basis for PILC behavior. To address this issue, targeted sequencing was performed to identify molecular alterations that define PILC. This sequencing analysis identified genes that distinguish PILC from classic ILC and invasive ductal carcinoma by the incidence of their genomic changes. In particular, insulin receptor substrate 2 (IRS2) is recurrently mutated in PILC, and pathway analysis reveals a role for the insulin receptor (IR)/insulin-like growth factor-1 receptor (IGF1R)/IRS2 signaling pathway in PILC. IRS2 mutations identified in PILC enhance invasion, revealing a role for this signaling adaptor in the aggressive nature of PILC.

Teaching of Independent Exercises for Prehabilitation in Breast Cancer.

We attempted to determine the feasibility of studying prehabilitation exercises to improve shoulder pain and abduction range of motion (ROM) after breast cancer surgery. We evaluated methods of exercise teaching and assessed effect on postsurgical seroma formation. This was a feasibility study with two non-blinded groups of subjects randomized by timing of appointment. This single-site study was performed at an academic tertiary medical center. Sixty cancer patients were randomly assigned to either group 1, in-person teaching arm, n = 36, or group 2, video-only teaching arm, n = 24. Forty-five patients completed the study. Shoulder exercises were assigned to both groups 1 month prior to surgery during evaluation. Group 1 received in-person instruction on exercises, plus an information sheet with exercises and a link to an online video. Group 2 received only the information sheet with exercises and a link to the online video. The primary outcomes considered are as follows: exercise compliance, shoulder pain (via visual analog scale), shoulder abduction ROM (via goniometer), and presence or absence of seroma. Seventy-six percent of study patients chose to exercise. There was no difference in exercise compliance between in-person teaching versus video teaching (75 %, 24/32 vs. 77 %, 10/13, OR = 1.03). Sixty-six of patients (20/30) lost greater than 10° shoulder abduction ROM at 1 month post surgery. Twenty-nine of patients (9/31) had worse shoulder pain than baseline at 1 month post surgery (24 %, 6/25 exercisers, and 50 %, 3/6 non-exercisers). Fifteen percent of patients (4/27) had worse shoulder pain than baseline at 3 months post surgery (8 %, 2/23 exercisers, and 100 %, 2/2 non-exercisers). Prehabilitation exercise program inferred no additional risk of seroma formation (Exercisers 21 %, 7/33 vs. non-exercisers 22 %, 2/9, OR = 0.94). Our subjects were able to perform three exercises independently in the preoperative period. A high-quality randomized controlled trial is necessary to assess the appropriate timing and efficacy of this intervention.

Eastern Canadian Gastrointestinal Cancer Consensus Conference 2016.

The annual Eastern Canadian Gastrointestinal Cancer Consensus Conference 2016 was held in Montreal, Quebec, 5-7 February. Experts in radiation oncology, medical oncology, surgical oncology, and infectious diseases involved in the management of patients with gastrointestinal malignancies participated in presentations and discussion sessions for the purpose of developing the recommendations presented here. This consensus statement addresses multiple topics: ■ Follow-up and survivorship of patients with resected colorectal cancer■ Indications for liver metastasectomy■ Treatment of oligometastases by stereotactic body radiation therapy■ Treatment of borderline resectable and unresectable pancreatic cancer■ Transarterial chemoembolization in hepatocellular carcinoma■ Infectious complications of antineoplastic agents.

Plant-derived H7 VLP vaccine elicits protective immune response against H7N9 influenza virus in mice and ferrets.

In March 2013, the Chinese Centre for Disease Control and Prevention confirmed the first reported case of human infection with an avian influenza A H7N9 virus. Infection with this virus often caused severe pneumonia and acute respiratory distress syndrome resulting in a case fatality rate >35%. The risk of pandemic highlighted, once again, the need for a more rapid and scalable vaccine response capability. Here, we describe the rapid (19 days) development of a plant-derived VLP vaccine based on the hemagglutinin sequence of influenza H7N9 A/Hangzhou/1/2013. The immunogenicity of the H7 VLP vaccine was assessed in mice and ferrets after one or two intramuscular dose(s) with and without adjuvant (alum or GLA-SE™). In ferrets, we also measured H7-specific cell-mediated immunity. The mice and ferrets were then challenged with H7N9 A/Anhui/1/2013 influenza virus. A single immunization with the adjuvanted vaccine elicited a strong humoral response and protected mice against an otherwise lethal challenge. Two doses of unadjuvanted vaccine significantly increased humoral response and resulted in 100% protection with significant reduction of clinical signs leading to nearly asymptomatic infections. In ferrets, a single immunization with the alum-adjuvanted H7 VLP vaccine induced strong humoral and CMI responses with antigen-specific activation of CD3(+) T cells. Compared to animals injected with placebo, ferrets vaccinated with alum-adjuvanted vaccine displayed no weight loss during the challenge. Moreover, the vaccination significantly reduced the viral load in lungs and nasal washes 3 days after the infection. This candidate plant-made H7 vaccine therefore induced protective responses after either one adjuvanted or two unadjuvanted doses. Studies are currently ongoing to better characterize the immune response elicited by the plant-derived VLP vaccines. Regardless, these data are very promising for the rapid production of an immunogenic and protective vaccine against this potentially pandemic virus.

Comparison of randomized multifocal mapping and temporal phase mapping of visual cortex for clinical use.

fMRI is becoming an important clinical tool for planning and guidance of surgery to treat brain tumors, arteriovenous malformations, and epileptic foci. For visual cortex mapping, the most popular paradigm by far is temporal phase mapping, although random multifocal stimulation paradigms have drawn increased attention due to their ability to identify complex response fields and their random properties. In this study we directly compared temporal phase and multifocal vision mapping paradigms with respect to clinically relevant factors including: time efficiency, mapping completeness, and the effects of noise. Randomized, multifocal mapping accurately decomposed the response of single voxels to multiple stimulus locations and made correct retinotopic assignments as noise levels increased despite decreasing sensitivity. Also, multifocal mapping became less efficient as the number of stimulus segments (locations) increased from 13 to 25 to 49 and when duty cycle was increased from 25% to 50%. Phase mapping, on the other hand, activated more extrastriate visual areas, was more time efficient in achieving statistically significant responses, and had better sensitivity as noise increased, though with an increase in systematic retinotopic mis-assignments. Overall, temporal phase mapping is likely to be a better choice for routine clinical applications though random multifocal mapping may offer some unique advantages for selected applications.

Intrinsic functional connectivity of the brain swallowing network during subliminal esophageal acid stimulation.

BACKGROUND: Intrinsic synchronous fluctuations of the functional magnetic resonance imaging signal are indicative of the underlying 'functional connectivity' (FC) and serve as a technique to study dynamics of the neuronal networks of the human brain. Earlier studies have characterized the functional connectivity of a distributed network of brain regions involved in swallowing, called brain swallowing network (BSN). The potential modulatory effect of esophageal afferent signals on the BSN, however, has not been systematically studied. METHODS: Fourteen healthy volunteers underwent steady state functional magnetic resonance imaging across three conditions: (i) transnasal catheter placed in the esophagus without infusion; (ii) buffer solution infused at 1 mL/min; and (iii) acidic solution infused at 1 mL/min. Data were preprocessed according to the standard FC analysis pipeline. We determined the correlation coefficient values of pairs of brain regions involved in swallowing and calculated average group FC matrices across conditions. Effects of subliminal esophageal acidification and nasopharyngeal intubation were determined. KEY RESULTS: Subliminal esophageal acid stimulation augmented the overall FC of the right anterior insula and specifically the FC to the left inferior parietal lobule. Conscious stimulation by nasopharyngeal intubation reduced the overall FC of the right posterior insula, particularly the FC to the right prefrontal operculum. CONCLUSIONS & INFERENCES: The FC of BSN is amenable to modulation by sensory input. The modulatory effect of sensory pharyngoesophageal stimulation on BSN is mainly mediated through changes in the FC of the insula. The alteration induced by subliminal visceral esophageal acid stimulation is in different insular connections compared with that of conscious somatic pharyngeal stimulation.

Characterization of the ultrasound beam produced by the MIST therapy, wound healing system.

The MIST Therapy wound healing device (Celleration, Eden Prairie, MN, USA), which uses low-frequency ultrasound to deliver an atomized saline spray to acute wounds, was evaluated in a laboratory environment. The output of the MIST device was characterized by its frequency, transmission in the presence and absence of the saline spray and intensity. When measured up to 500 mm away from the transducer tip, the transmission of 39.5 kHz ultrasound was not significantly attenuated by the saline itself. In the absence of the saline spray, the acoustic intensity range of the MIST device was calculated to be 429-188 mW cm(-2) across the manufacturer-specified treatment range (12.5-20 mm). Because of the acoustic impedance mismatch between air and soft tissue, the MIST Therapy device would deliver only 0.1% of this incident intensity into the wound site.

Meeting complex needs: young people with HIV in London.

OBJECTIVES: The aim of the study was to examine the service use and characteristics of young people diagnosed with HIV infection aged under 25 years in order to design appropriate services. METHODS: A retrospective review of medical records of all individuals diagnosed as HIV positive aged under 25 years at Chelsea and Westminster Hospital, London, UK was carried out. The Health Protection Agency traced all individuals who had been lost to follow-up. We collected demographic, clinical, social and behavioural data. RESULTS: Of the 100 individuals diagnosed as HIV positive aged <25 years, 91% acquired HIV sexually; the median age at diagnosis was 21 years. Fifty-nine per cent were born outside the UK. Of 91 individuals diagnosed in the UK, 20% were diagnosed outside genitourinary medicine. Almost half had tested HIV negative a median of 13 months previously. At HIV diagnosis, 26% had a concurrent sexually transmitted infection; thereafter 34% had a documented risk of HIV transmission. The prevalence of psychiatric comorbidity was high (23%). Cervical screening rates were low; of nine women screened, five required treatment for cervical or vulval neoplasia. One fifth of the cohort were lost to follow-up a median 6 months from diagnosis. CONCLUSIONS: Young people with sexually acquired HIV infection have complex medical and psychosocial needs and many disengage from health services. Current services are not meeting the needs of these young people. Specialist young people's clinics may improve standards of care for this vulnerable group.

Assessing breast cancer angiogenesis in vivo: which susceptibility contrast MRI biomarkers are relevant?

PURPOSE: There is an impending need for noninvasive biomarkers of breast cancer angiogenesis to evaluate the efficacy of new anti-angiogenic therapies in vivo. The purpose of this study was to systematically evaluate the sensitivity of in vivo steady-state susceptibility contrast-MRI biomarkers of angiogenesis in a human breast cancer model. METHODS: Orthotopic MDA-MB-231 human breast cancer xenografts were imaged by steady-state susceptibility contrast-MRI at post-inoculation week 3 and post-inoculation week 5, followed by ex vivo whole tumor 3D micro-CT angiography. "Absolute" (i.e., measures of vascular morphology in appropriate units) and "relative" (i.e., proportional to measures of vascular morphology) MRI biomarkers of tumor blood volume, vessel size, and vessel density were computed and their ability to predict the corresponding micro-CT analogs assessed using cross-validation analysis. RESULTS: All MRI biomarkers significantly correlated with their micro-CT analogs and were sensitive to the micro-CT-measured decreases in tumor blood volume and vessel density from post-inoculation week 3 to post-inoculation week 5. However, cross-validation analysis revealed there was no significant difference between the predictive accuracy of "absolute" and "relative" biomarkers. CONCLUSION: As "relative" biomarkers are more easily computed from steady-state susceptibility contrast-MRI (i.e., without additional MRI measurements) than "absolute" biomarkers, it makes them promising candidates for assessing breast cancer angiogenesis in vivo.

Prophylactic mesh placement of permanent stomas at index operation for colorectal cancer.

INTRODUCTION: Parastomal herniation occurs in 30-50% of colostomy formations. The aim of this study was to radiologically evaluate the mechanical defects at stoma sites in patients who had previously undergone a permanent colostomy with or without mesh at the index operation for colorectal cancer. METHODS: A study was performed of all colorectal cancer patients (n=41) having an end colostomy between 2002 and 2010, with or without Prolene(®) mesh plication, with blinded evaluation of the annual follow-up staging computed tomography (CT) for stomal characteristics. The presence of parastomal hernias, volume, dimensions, grade of the parastomal hernia and abdominal wall defect size were measured by two independent radiologists, and compared with demographic and operative variables. RESULTS: In those patients with radiological evidence of a parastomal hernia, Prolene(®) mesh plication significantly reduced the incidence of bowel containing parastomal hernias at one year following the procedure (p<0.05) and also reduced the diameter of the abdominal wall defect (p=0.006). CONCLUSIONS: Prophylactic mesh placement at the time of the index procedure reduces the diameter of abdominal wall aperture and the incidence of parastomal hernias containing bowel. Future studies should use both objective radiological as well as clinical endpoints when assessing parastomal hernia development with and without prophylactic mesh.

Evolutionary genomics of Colias Phosphoglucose Isomerase (PGI) introns.

Little is known of intron sequences' variation in cases where eukaryotic gene coding regions undergo strong balancing selection. Phosphoglucose isomerase, PGI, of Colias butterflies offers such a case. Its 11 introns include many point mutations, insertions, and deletions. This variation changes with intron position and length, and may leave little evidence of homology within introns except for their first and last few basepairs. Intron position is conserved between PGIs of Colias and the silkmoth, but no intron sequence homology remains. % GC content and length are functional properties of introns which can affect whole-gene transcription; we find a relationship between these properties which may indicate selection on transcription speed. Intragenic recombination is active in these introns, as in coding sequences. The small extent of linkage disequilibrium (LD) in the introns decays over a few hundred basepairs. Subsequences of Colias introns match subsequences of other introns, untranslated regions of cDNAs, and insect-related transposons and pathogens, showing that a diverse pool of sequence fragments is the source of intron contents via turnover due to deletion, recombination, and transposition. Like Colias PGI's coding sequences, the introns evolve reticulately with little phylogenetic signal. Exceptions are coding-region allele clades defined by multiple amino acid variants in strong LD, whose introns are closely related but less so than their exons. Similarity of GC content between introns and flanking exons, lack of small introns despite mutational bias toward deletion, and findings already mentioned suggest constraining selection on introns, possibly balancing transcription performance against advantages of higher recombination rate conferred by intron length.