The Contribution of Mutation to Variation in Temperature-Dependent Sprint Speed in Zebrafish, Danio rerio.

AbstractThe contribution of new mutations to phenotypic variation and the consequences of this variation for individual fitness are fundamental concepts for understanding genetic variation and adaptation. Here, we investigated how mutation influenced variation in a complex trait in zebrafish, Danio rerio. Typical of many ecologically relevant traits in ectotherms, swimming speed in fish is temperature dependent, with evidence of adaptive evolution of thermal performance. We chemically induced novel germline point mutations in males and measured sprint speed in their sons at six temperatures (between 16°C and 34°C). Heterozygous mutational effects on speed were strongly positively correlated among temperatures, resulting in statistical support for only a single axis of mutational variation, reflecting temperature-independent variation in speed (faster-slower mode). These results suggest pleiotropic effects on speed across different temperatures; however, spurious correlations arise via linkage or heterogeneity in mutation number when mutations have consistent directional effects on each trait. Here, mutation did not change mean speed, indicating no directional bias in mutational effects. The results contribute to emerging evidence that mutations may predominantly have synergistic cross-environment effects, in contrast to conditionally neutral or antagonistic effects that underpin thermal adaptation. We discuss several aspects of experimental design that may affect resolution of mutations with nonsynergistic effects.

Effectiveness of containment strategies in preventing SARS-CoV-2 transmission.

BACKGROUND: Despite substantial resources deployed to curb SARS-CoV-2 transmission, controlling the COVID-19 pandemic has been a major challenge. New variants of the virus are frequently emerging leading to new waves of infection and re-introduction of control measures. In this study, we assessed the effectiveness of containment strategies implemented in the early phase of the pandemic. METHODS: Real-world data for COVID-19 cases was retrieved for the period Jan 1 to May 1, 2020 from a number of different sources, including PubMed, MEDLINE, Facebook, Epidemic Forecasting and Google Mobility Reports. We analyzed data for 18 countries/regions that deployed containment strategies such as travel restrictions, lockdowns, stay-at-home requests, school/public events closure, social distancing, and exposure history information management (digital contact tracing, DCT). Primary outcome measure was the change in the number of new cases over 30 days before and after deployment of a control measure. We also compared the effectiveness of centralized versus decentralized DCT. Time series data for COVID-19 were analyzed using Mann-Kendall (M-K) trend tests to investigate the impact of these measures on changes in the number of new cases. The rate of change in the number of new cases was compared using M-K z-values and Sen's slope. RESULTS: In spite of the widespread implementation of conventional strategies such as lockdowns, travel restrictions, social distancing, school closures, and stay-at-home requests, analysis revealed that these measures could not prevent the spread of the virus. However, countries which adopted DCT with centralized data storage were more likely to contain the spread. CONCLUSIONS: Centralized DCT was more effective in containing the spread of COVID-19. Early implementation of centralized DCT should be considered in future outbreaks. However, challenges such as public acceptance, data security and privacy concerns will need to be addressed.

How to choose an abdominal imaging fellowship.

Radiologists in training draw from their early experiences in residency when choosing a fellowship. Once they have decided on an abdominal imaging fellowship, applicants must learn to navigate the interview process. During this challenging time, applicants explore the difference in clinical curricula and rotations, meet potential mentors and clinical faculty, consider potential academic interests and projects, and choose what location they would like to train for one year after residency. When in training, fellows undergo the challenge of finding employment while learning new skills and refining their abilities to become a well-rounded radiologist and clinician. This article summarizes key points potential applicants should consider when deciding on an abdominal imaging fellowship, how to prepare for the interview season, and how to plan their fellowship year before fellows take the next step to becoming attendings.

Bowel Wall Visualization Using MR Enterography in Relationship to Bowel Lumen Contents and Patient Demographics.

BACKGROUND: MR enterography (MRE) is generally performed without bowel preparation, but the frequency and extent by which bowel contents affect bowel wall visualization are poorly described in the literature. PURPOSE: To evaluate MRE bowel wall visualization quality relative to bowel lumen contents and patient demographics. STUDY TYPE: Retrospective, single-center. POPULATION: One hundred and four consecutive patients (mean age 29 years, range 5-76 years) without prior bowel resection who had undergone MRE. FIELD STRENGTH/SEQUENCE: 3 T (N = 87) or 1.5 T (N = 17)/T2-weighted single-shot spin echo (T2WI) and fat-saturated T1-weighted gradient echo (T1WI) without and with gadolinium. ASSESSMENT: For the proximal and distal jejunum and ileum and colon, three readers independently categorized bowel lumen signal (water = bright T2 dark T1, T1-bright, or air = dark T2 and T1 signal) and scored distension (0 = poor, 1 = moderate, 2 = well) and wall enhancement (0 = unclear, 1 = perceptible, 2 = clear) based upon gadolinium enhanced T1WI for the 104 MRE exams). The bowel visualization score was the sum of the wall enhancement and distension scores and was considered adequate if ≥3. STATISTICAL TESTS: Wilcoxon signed-rank test. RESULTS: The bowel lumen content was water signal in 93% (97/104 scans), 92% (95/104), 98% (102/104), and 93% (92/104) of the proximal and distal jejunum and proximal and distal ileum, respectively, but only in 12.5% (13/104) of the colon. There was adequate bowel visualization of 53.8%, 77.8%, 84.6%, 90.4% of the proximal and distal jejunum and proximal and distal ileum, respectively, but only 19.2% of the colon. In children (age < 18 years), the visualization score of the ileum was lower when the adjacent colon contained air (2.4 ± 0.97) compared to water (3.75 ± 0.29, P < 0.05) or T1-bright material (3.21 ± 0.82, P < 0.05). DATA CONCLUSION: Without bowel preparation, colon wall visualization was often unsatisfactory at MRE, and air-filled colon also degraded small bowel visualization, particularly in children. LEVEL OF EVIDENCE: 4 TECHNICAL EFFICACY: Stage 1.

Imaging in Gender Affirmation Surgery.

PURPOSE OF REVIEW: This review summarizes recent developments in gender affirmation surgery, imaging findings in patients undergoing these surgeries, focusing on common postoperative radiologic appearances, complications, and pitfalls in interpretation. RECENT FINDINGS: The imaging workup of masculinizing and feminizing genitourinary surgeries uses multiple modalities in presurgical planning and within the immediate and long-term postoperative period. CT and MRI can help identify immediate and remote postoperative complications. Fluoroscopic examinations can diagnose postoperative urethral complications after gender affirmation surgeries. Lastly, the patients can undergo imaging for unrelated acute and chronic pathology, and knowledge of these imaging findings can be very helpful. Imaging plays a significant role in the care of transgender patients and, particularly, in those pursuing gender affirmation surgery. As insurance coverage expands for these surgical procedures, radiologists should be prepared to encounter, understand, and interpret pre and postoperative findings.

Practical methods for culturing parasitic gnathiid isopods.

The reliance of parasites on their hosts makes host-parasite interactions ideal models for exploring ecological and evolutionary processes. By providing a consistent supply of parasites, in vivo monocultures offer the opportunity to conduct experiments on a scale that is generally not otherwise possible. Gnathiid isopods are common ectoparasites of marine fishes, and are becoming an increasing focus of research attention due to their experimental amenability and ecological importance as ubiquitous, harmful, blood-feeding "mosquito-like" organisms. They feed on hosts once during each of their three juvenile stages, and after each feeding event they return to the benthos to digest and moult to the next stage. Adults do not feed and remain in the benthos, where they reproduce and give birth. Here, we provide methods of culturing gnathiids, and highlight ways in which gnathiids can be used to examine parasite-host-environment interactions. Captive-raised gnathiid juveniles are increasingly being used in parasitological research; however, the methodology for establishing gnathiid monocultures is still not widely known. Information to obtain in vivo monocultures on teleost fish is detailed for a Great Barrier Reef (Australia) and a Caribbean Sea (US Virgin Islands) gnathiid species, and gnathiid information gained over two decades of successfully maintaining continuous cultures is summarised. Providing a suitable benthic habitat for the predominantly benthic free-living stage of this parasite is paramount. Maintenance comprises provision of adequate benthic shelter, managing parasite populations, and sustaining host health. For the first time, we also measured gnathiids' apparent attack speed (maximum 24.5 cm sec-1; 6.9, 4.9/17.0, median, 25th/75th quantiles) and illustrate how to collect such fast moving ectoparasites in captivity for experiments. In addition to providing details pertaining to culture maintenance, we review research using gnathiid cultures that have enabled detailed scientific understanding of host and parasite biology, behaviour and ecology on coral reefs.

Acute diverticulitis: Key features for guiding clinical management.

Diverticular disease of the colon and small bowel is an important cause of pathology leading to emergency department visits and urgent gastrointestinal surgery. CT is a highly sensitive and specific modality for the diagnosis of acute diverticulitis and its complications as well as for the exclusion of alternate causes of pathology. Ultrasound, MRI and virtual CT colonoscopy have important adjunct roles for screening and workup of complications in specific patient populations. While diverticular disease most commonly involves the descending and sigmoid colon, it can also affect the proximal colon and small bowel. Acute diverticulitis may be categorized as uncomplicated or complicated according to the degree of inflammatory changes and related complications it induces, although some degree of overlap exists in clinical practice. Uncomplicated diverticulitis is classically characterized by localized inflammation surrounding a diverticulum ranging from wall thickening and phlegmonous change to the development of small, localized pericolic abscesses. Complicated forms of disease manifest with larger pericolic and distant abscesses, fistulae to adjacent organs, perforation, and peritonitis. Recurrent episodes of diverticulitis may lead to muscular hypertrophy of the bowel wall and luminal narrowing, potentially leading to bowel obstruction. Several imaging features may help to differentiate diverticulitis from colonic malignancy, however this remains a diagnostic imaging challenge that often requires further evaluation with colonoscopy. In this review, we discuss the pathophysiology and key imaging features of acute diverticulitis and its complications. We explore both common and uncommon presentations of the disease involving the colon and small bowel, acute and chronic manifestations of disease, and pitfalls to recognize when imaging alone may be insufficient to distinguish benign from malignant.

Endometriosis in pregnancy.

Endometriosis constitutes the presence of ectopic endometrial glands and stroma outside the uterine endometrium, which is hormonally responsive and responds to pregnancy hormones as well. Decidualization is a physiologic process, where the normal endometrium readies itself for optimal accommodation of a pregnancy. A similar hormonal response can be seen with ectopic endometrium as well. As such, ovarian endometriomas and deep endometriosis implants can undergo decidualization. Overall, the progestational state of pregnancy favors an improvement in endometriosis, however, decidualization can lead to findings that can lead to increased size of endometriomas and deep infiltrative endometriosis implants, changes in imaging appearance and even complications, such as spontaneous hemoperitoneum in pregnancy. Awareness of this process can help prevent misdiagnosis of decidualized endometriomas as ovarian malignancy and recognize common imaging manifestations of hormonal effects of pregnancy on endometriosis.

Updated guidelines for intravenous contrast use for CT and MRI.

Intravenous (IV) contrast material is used extensively for CT and MRI scans done in emergency departments (ED). Its use is essential to make many critical diagnoses in ED patients. While adverse reactions can occur, newer research has added to our knowledge of IV contrast media tolerance and safety leading to improved and more liberal guidelines for intravenous contrast use. The updated information described in this review article indicates how intravenous contrast can be used safely in more patients, more expeditiously and with fewer precautions than with prior guidelines. This review article explains the basis for the new recommendations for intravenous contrast material use and describes indicated precautions and preparations to avoid adverse reactions for iodinated agents used for CT and gadolinium agents for MRI.

Right- versus Left-Sided Chest Ports in Oncologic Patients with a History of Right-Sided Port Removal: Are There Any Differences in the Complication Rates?

PURPOSE: To compare chest port (port)-related complication rates between right- and left-sided ports placed in adult oncologic patients with a history of right-sided port removal. MATERIALS AND METHODS: A retrospective chart review identified 90 adult oncologic patients with a history of right-sided port removal. Of these, 60 patients had a second port placed on the right side (right-side group), while 30 patients had a second port placed on the left side (left-side group). Median time between first port removal and second port placement was 217 days (range, 0-3808 days). Port-related complications included infection (port-site and/or bloodstream), mechanical, thrombotic, and port-site skin complications. Complication rates between groups were compared. Proportional subdistribution hazard regression (PSHREG) was conducted to determine if laterality of the second port is an independent risk factor for port-related complications. RESULTS: The cumulative follow-up period was 34,748 catheter-days (median, 233; range, 9-2162 days). Eleven patients (18.3%) in the right-side group and 2 patients (6.7%) in the left-side group had port-related complications (P = .21), accounting for complication rates of 0.5 and 0.2/1000 catheter-days (P = .24), respectively. No statistical difference was found in the incidence of infection (9/60 vs 1/30, P = .16), mechanical (0/60 vs. 1/30, P = .33), thrombotic (1/60 vs 0/30, P = 1.0), and skin-related (1/60 vs 0/30, P = 1.0) complications between groups. In multivariate PSHREG, laterality of the second port (hazard ratio = 3.09, 95% confidence interval = 0.81-11.76, P = .10) was not a significant risk factor for port-related complications. CONCLUSIONS: In adult oncologic patients with a history of right-sided port removal, no significant differences in port-related complication rates were observed between right- and left-sided second ports.

Cleaner wrasse indirectly affect the cognitive performance of a damselfish through ectoparasite removal.

Cleaning organisms play a fundamental ecological role by removing ectoparasites and infected tissue from client surfaces. We used the well-studied cleaning mutualisms involving the cleaner wrasse, Labroides dimidiatus, to test how client cognition is affected by ectoparasites and whether these effects are mitigated by cleaners. Ambon damselfish (Pomacentrus amboinensis) collected from experimental reef patches without cleaner wrasse performed worse in a visual discrimination test than conspecifics from patches with cleaners. Endoparasite abundance also negatively influenced success in this test. Visual discrimination performance was also impaired in damselfish experimentally infected with gnathiid (Crustacea: Isopoda) ectoparasites. Neither cleaner absence nor gnathiid infection affected performance in spatial recognition or reversal learning tests. Injection with immune-stimulating lipopolysaccharide did not affect visual discrimination performance relative to saline-injected controls, suggesting that cognitive impairments are not due to an innate immune response. Our results highlight the complex, indirect role of cleaning organisms in promoting the health of their clients via ectoparasite removal and emphasize the negative impact of parasites on host's cognitive abilities.

Association between misty mesentery with baseline or new diagnosis of cancer: a matched cohort study.

We compared the prevalence of a baseline diagnosis of cancer in patients with and without misty mesentery (MM) and determined its association with the development of a new cancer. This was a retrospective, HIPAA-compliant, IRB-approved case-control study of 148 cases and 4:1 age- and gender-matched controls. Statistical tests included chi-square, t-test, hazard models, and C-statistic. Patients with MM were less likely to have cancer at baseline (RR=0.74, p=0.003), but more likely to develop a new malignancy on follow-up (RR=2.13, p=0.003; survival analysis HR 1.74, p=0.05). MM may confer an increased probability of later developing cancer, particularly genitourinary tumors.

Pelvic Beam-Hardening Artifacts in Dual-Energy CT Image Reconstructions: Occurrence and Impact on Image Quality.

OBJECTIVE: The purpose of this study was to describe the frequency and appearance of beam-hardening artifacts on rapid-kilovoltage-switching dual-energy CT (DECT) image reconstructions of the pelvis. MATERIALS AND METHODS: Monochromatic (70, 52, and 120 keV) and material decomposition CT images (iodine-water and water-iodine) from consecutive pelvic rapid-kilovoltage-switching DECT scans were retrospectively evaluated. We recorded the presence, type (high versus low attenuation), and severity of beam-hardening artifacts (Likert scale from 0, barely seen, to 4, severe), clarity of anatomic delineation (Likert scale from 0, unimpaired, to 4, severely impaired) and SD of CT numbers, iodine and water concentrations, and gray-scale values for artifact-affected regions and corresponding unaffected reference tissue. A pelvic phantom was scanned and evaluated in a similar manner. Wilcoxon signed rank and paired t tests were used to compare results between the image reconstructions. RESULTS: Beam-hardening artifacts were seen in all image reconstructions in all 41 patients (22 men, 19 women; mean age, 57 years; range 22-86 years) who met the inclusion criteria. The median artifact severity score was worse for water-iodine and iodine-water images (score of 3 for each) than for 70-keV (score 1), 52-keV (score 2), and 120-keV (score 1) images (all p < 0.001). The anatomic delineation was worse (p < 0.001) for water-iodine and iodine-water images than for monochromatic images. Higher CT number SD values, material concentrations, and gray-scale values were found for areas affected by artifacts than for reference tissues in all datasets (all p < 0.001). Similar results were seen in the phantom study. CONCLUSION: Beam-hardening artifacts are prevalent in pelvic rapid-kilovoltage-switching DECT and more severe in material decomposition than monochromatic image reconstructions.

Presence of cleaner wrasse increases the recruitment of damselfishes to coral reefs.

Mutualisms affect the biodiversity, distribution and abundance of biological communities. However, ecological processes that drive mutualism-related shifts in population structure are often unclear and must be examined to elucidate how complex, multi-species mutualistic networks are formed and structured. In this study, we investigated how the presence of key marine mutualistic partners can drive the organisation of local communities on coral reefs. The cleaner wrasse, Labroides dimidiatus, removes ectoparasites and reduces stress hormones for multiple reef fish species, and their presence on coral reefs increases fish abundance and diversity. Such changes in population structure could be driven by increased recruitment of larval fish at settlement, or by post-settlement processes such as modified levels of migration or predation. We conducted a controlled field experiment to examine the effect of cleaners on recruitment processes of a common group of reef fishes, and showed that small patch reefs (61-285 m(2)) with cleaner wrasse had higher abundances of damselfish recruits than reefs from which cleaner wrasse had been removed over a 12-year period. However, the presence of cleaner wrasse did not affect species diversity of damselfish recruits. Our study provides evidence of the ecological processes that underpin changes in local population structure in the presence of a key mutualistic partner.

Liquid-Infused Silicone As a Biofouling-Free Medical Material.

There is a dire need for infection prevention strategies that do not require the use of antibiotics, which exacerbate the rise of multi- and pan-drug resistant infectious organisms. An important target in this area is the bacterial attachment and subsequent biofilm formation on medical devices (e.g., catheters). Here we describe nonfouling, lubricant-infused slippery polymers as proof-of-concept medical materials that are based on oil-infused polydimethylsiloxane (iPDMS). Planar and tubular geometry silicone substrates can be infused with nontoxic silicone oil to create a stable, extremely slippery interface that exhibits exceptionally low bacterial adhesion and prevents biofilm formation. Analysis of a flow culture of Pseudomonas aeruginosa through untreated PDMS and iPDMS tubing shows at least an order of magnitude reduction of biofilm formation on iPDMS, and almost complete absence of biofilm on iPDMS after a gentle water rinse. The iPDMS materials can be applied as a coating on other polymers or prepared by simply immersing silicone tubing in silicone oil, and are compatible with traditional sterilization methods. As a demonstration, we show the preparation of silicone-coated polyurethane catheters and significant reduction of Escherichia coli and Staphylococcus epidermidis biofilm formation on the catheter surface. This work represents an important first step toward a simple and effective means of preventing bacterial adhesion on a wide range of materials used for medical devices.

Granulomatous mastitis: changing clinical and imaging features with image-guided biopsy correlation.

OBJECTIVES: To review clinical presentation, revisit patient demographics and imaging findings in granulomatous mastitis and determine the optimal biopsy method for diagnosis. METHODS: A retrospective study was performed to review the clinical presentation, imaging findings and biopsy methods in patients with granulomatous mastitis. Twenty-seven patients with pathology-proven granulomatous mastitis were included. RESULTS: The average age at presentation was 38.0 years (range, 21-73 years). Seven patients were between 48 and 73 years old. Twenty-four patients presented with symptoms and three patients were asymptomatic. Nineteen patients were imaged with mammography demonstrating mammographically occult lesions as the predominant finding. Twenty-six patients were imaged with ultrasound and the most common finding was a mass lesion. Pathological diagnosis was made by image-guided biopsy in 44 % of patients. The imaging features of granulomatous mastitis on mammography are infrequently described. CONCLUSIONS: Our study demonstrates that granulomatous mastitis can occur in postmenopausal or asymptomatic patients, although previously reported exclusively in young women with palpable findings. Presentation on mammography as calcifications requiring mammographically guided vacuum-assisted biopsy has not been previously described. The diagnosis of granulomatous mastitis can easily be made by image-guided biopsy and surgical excision should be reserved for definitive treatment. KEY POINTS: • Characterizes radiographic appearance of granulomatous mastitis in postmenopausal or asymptomatic patients. • Granulomatous mastitis can present exclusively as calcifications on mammography. • The diagnosis of granulomatous mastitis is made by image-guided biopsy techniques.

Pseudobacciger cheneyae n. sp. (Digenea: Gymnophalloidea) from Weber's chromis (Chromis weberi Fowler & Bean) (Perciformes: Pomacentridae) at Lizard Island, Great Barrier Reef, Australia.

A new species of digenean, Pseudobacciger cheneyae n. sp., is described from the intestines of Weber's chromis (Chromis weberi Fowler & Bean) from off Lizard Island, Great Barrier Reef, Australia. This species differs from the three described species of Pseudobacciger Nahhas & Cable, 1964 [P. cablei Madhavi, 1975, P. harengulae Yamaguti, 1938 and P. manteri Nahhas & Cable, 1964] in combinations of the size of the suckers and the length of the caeca. The host of the present species is a perciform (Family Pomacentridae) which contrasts with previous records of the genus which are almost exclusively from clupeiform fishes. The genus Pseudobacciger is presently recognised within the family Faustulidae (Poche, 1926) but phylogenetic analyses of 28S and ITS2 rDNA show that the new species bears no relationship to species of four other faustulid genera (Antorchis Linton, 1911, Bacciger Nicoll, 1924, Paradiscogaster Yamaguti, 1934 and Trigonocryptus Martin, 1958) but that instead it is nested within the Gymnophalloidea (Odhner, 1905) as sister to the Tandanicolidae (Johnston, 1927). This result suggests that the Faustulidae is polyphyletic.