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Gallbladder polyps (also known as polypoid lesions of the gallbladder) are a common incidental finding. The vast majority of gallbladder polyps smaller than 10 mm are not true neoplastic polyps but are benign cholesterol polyps with no inherent risk of malignancy. In addition, recent studies have shown that the overall risk of gallbladder cancer is not increased in patients with small gallbladder polyps, calling into question the rationale for frequent and prolonged follow-up of these common lesions. In 2021, a Society of Radiologists in Ultrasound, or SRU, consensus conference was convened to provide recommendations for the management of incidentally detected gallbladder polyps at US. See also the editorial by Sidhu and Rafailidis in this issue.

BackgroundOptimizing respiratory support after birth requires real-time feedback on lung aeration. We hypothesized that lung ultrasound (LUS) can accurately monitor the extent and progression of lung aeration after birth and is closely associated with oxygenation.MethodsNear-term (140 days gestation, term ∼147 days), spontaneously breathing lambs with normal (controls; n = 10) or elevated lung liquid levels (EL; n= 9) were delivered by Caesarean section and monitored for four hours after birth. LUS (Phillips CX50, L3–12 transducer) images and arterial blood gases were taken every 5–20 min. LUS images were analyzed both qualitatively (grading) and quantitatively (using the coefficient of variation of pixel intensity (CoV) to estimate the degree of lung aeration), which was correlated with the oxygen exchange capacity of the lungs (Alveolar-arterial difference in oxygen; AaDO2).ResultsLung aeration, measured using LUS, and the AaDO2 improved over the first 4 h after birth. The increase in lung aeration measured using CoV of pixel intensity, but not LUS grade, was significantly reduced in EL lambs compared to controls (p = 0.02). The gradual decrease in AaDO2 after birth was significantly correlated with increased lung aeration in both control (grade, r2 = 0.60, p 2 = 0.54, p 2 = 0.51, p 2 = 0.44, p ConclusionsLUS can monitor lung aeration and liquid clearance after birth in spontaneously breathing near-term lambs. Image analysis techniques (CoV) may be able detect small to moderate differences in lung aeration in conditions with lung liquid retention which are not readily identified using qualitative LUS grading.

Contrast-enhanced US (CEUS), similar to other radiologic modalities, requires specific technical considerations and is subject to image artifacts. These artifacts may affect examination quality, negatively impact diagnostic accuracy, and decrease user comfort when using this emerging technique. Some artifacts are related to commonly known gray-scale US artifacts that can also appear on the contrast-only image (tissue-subtracted image obtained with the linear responses from background tissues nulled). These may include acoustic shadowing and enhancement; reverberation, refraction, and reflection; and poor penetration. Other artifacts are exclusive to CEUS owing to the techniques used for contrast mode image generation and the unique properties of the microbubbles that constitute ultrasound-specific contrast agents (UCAs). UCA-related artifacts may appear on the contrast-only image, the gray-scale image, or various Doppler mode images. Artifacts related to CEUS may include nonlinear artifacts and unintentional microbubble destruction resulting in pseudowashout. The microbubbles themselves may result in specific artifacts such as pseudoenhancement, signal saturation, and attenuation and shadowing and can confound the use of color and spectral Doppler US. Identifying and understanding these artifacts and knowing how to mitigate them may improve the quality of the imaging study, increase user confidence, and improve patient care. The authors review the principles of UCAs and the sound-microbubble interaction, as well as the technical aspects of image generation. Technical considerations, including patient positioning, depth, acoustic window, and contrast agent dose, also are discussed. Specific artifacts are described, with tips on how to identify and, if necessary, apply corrective measures, with the goal of improving examination quality.

The Ultrasound Liver Imaging Reporting and Data System (US LI-RADS), introduced in 2017 by the American College of Radiology, standardizes the technique, interpretation, and reporting of screening and surveillance ultrasounds intended to detect hepatocellular carcinoma in high-risk patients. These include patients with cirrhosis of any cause as well as subsets of patients with chronic hepatitis B viral infection. The US LI-RADS scheme is composed of an ultrasound category and a visualization score: ultrasound categories define the exam as negative, subthreshold, or positive and direct next steps in management; visualization scores denote the expected sensitivity of the exam, based on adequacy of liver visualization with ultrasound. Since its introduction, multiple institutions across the United States have implemented US LI-RADS. This review includes a background of hepatocellular carcinoma and US LI-RADS, definition of screening/surveillance population, recommendations and tips for technique, interpretation, and reporting, and preliminary outcomes analysis.

In the adaptive immune system, V(D)J recombination initiates the production of a diverse antigen receptor repertoire in developing B and T cells. Recombination activating proteins, RAG1 and RAG2 (RAG1/2), catalyze V(D)J recombination by cleaving adjacent to recombination signal sequences (RSSs) that flank antigen receptor gene segments. Previous studies defined the consensus RSS as containing conserved heptamer and nonamer sequences separated by a less conserved 12 or 23 base-pair spacer sequence. However, many RSSs deviate from the consensus sequence. Here, we developed a cell-based, massively parallel assay to evaluate V(D)J recombination activity on thousands of RSSs where the 12-RSS heptamer and adjoining spacer region contained randomized sequences. While the consensus heptamer sequence (CACAGTG) was marginally preferred, V(D)J recombination was highly active on a wide range of non-consensus sequences. Select purine/pyrimidine motifs that may accommodate heptamer unwinding in the RAG1/2 active site were generally preferred. In addition, while different coding flanks and nonamer sequences affected recombination efficiency, the relative dependency on the purine/pyrimidine motifs in the RSS heptamer remained unchanged. Our results suggest RAG1/2 specificity for RSS heptamers is primarily dictated by DNA structural features dependent on purine/pyrimidine pattern, and to a lesser extent, RAG:RSS base-specific interactions.

The TLR4-interacting SPA4 peptide suppresses inflammation. We assessed the structural and physicochemical properties and binding of SPA4 peptide to TLR4–MD2. We also studied the changes at the whole transcriptome level, cell morphology, viability, secreted cytokines and chemokines, and cell influx in cell systems and mouse models challenged with LPS and treated with SPA4 peptide. Our results demonstrated that the SPA4 peptide did not alter the cell viability and size and only moderately affected the transcriptome of the cells. Computational docking and rendering suggested that the SPA4 peptide intercalates with LPS-induced TLR4–MD2 complex. Results with alanine mutations of D-2 amino acid and NYTXXXRG-12-19 motif of SPA4 peptide suggested their role in binding to TLR4 and in reducing the cytokine response against LPS stimulus. Furthermore, therapeutically administered SPA4 peptide significantly suppressed the secreted levels of cytokines and chemokines in cells and bronchoalveolar lavage fluids of LPS-challenged mice. The results suggest that the SPA4 peptide intercalates with LPS-induced TLR4 complex and signaling for the suppression of inflammation.

The Ultrasound Liver Imaging Reporting and Data Systems (LI-RADS) provides standardized terminology and reporting for ultrasound (US) examinations performed for hepatocellular cancer (HCC) screening. However, there are no recommendations regarding follow up imaging for visualization scores with suboptimal visualization. Therefore, the aim of this study is to examine follow up imaging practices in the setting of US studies scored as B (moderate limitations) and C (severe limitations).A single center retrospective analysis of studies from 2017 to 2021 with HCC US screening visualization scores of B and C was performed. Follow up imaging with US, CT, or MRI within 6 months with visualization score B or C on initial US were included.Five hundred and sixty HCC US studies with suboptimal imaging were reviewed. Of those with follow up imaging, patients with a visualization score of B underwent US in more than half (58%) of the cases while those with visualization score of C underwent more CT/MRI studies (62.5%, P = .12) Patients with visualization score of B had more MRI exams performed (55%) while patients with a visualization score of C underwent more CT exams (70%, P = .16).Currently, there are no guidelines instructing follow up imaging on HCC screening ultrasounds with poor visualization, and the data suggests that providers have taken a heterogeneous approach. This suggests a need for society recommendations on how to approach HCC screening ultrasounds in patients with suboptimal studies.

Acute liver failure (ALF) is a rare clinical entity with high morbidity and mortality frequently requiring liver transplantation for survival. Imaging, particularly with ultrasound, plays an important role, especially to distinguish patients with underlying chronic liver disease who have lower transplant priority. We discuss the clinical and imaging findings in the three subtypes of ALF using a multi-modality approach with an emphasis on ultrasound.

Diagnostic imaging after orthotopic liver transplant focuses primarily on depicting complications related to surgical hepatic vascular and biliary anastomoses. Less common preexisting vascular conditions include congenital anatomic variants, atherosclerosis, chronic portal venous thrombosis, splenic artery and variceal steal phenomena, and transarterial embolization (TAE) for hepatocellular carcinoma (HCC). If unappreciated or left untreated preoperatively, these conditions negatively impact the transplant by impairing hepatic arterial or portal vascular inflow. Many of the complications related to preexisting vascular conditions can be prevented or mitigated by proper performance and careful evaluation of preoperative imaging studies. The authors describe the diagnosis and treatment of complications arising from narrowing of the celiac axis by atherosclerosis and the median arcuate ligament, variant anatomy of the hepatic artery, insufficiency of the portal vein requiring surgical conduits, and large varices or an enlarged splenic artery and spleen that may steal blood and compromise hepatic arterial or venous inflow. While preoperative evaluation primarily involves CT and MRI, postoperative diagnosis involves screening with sonography and confirmation with other modalities. We propose the use of a preoperative checklist of vascular status and measurements in patients undergoing liver transplant. Reports of imaging studies in recipients after transplant should include details of surgical vascular anastomoses and conduits, any history of HCC and preoperative TAE, details of the preoperative α-fetoprotein levels, and any unusual procedures or pathologic findings in the explanted liver that may affect postoperative surveillance. The authors review the pretransplant imaging evaluation of vascular and HCC issues that may affect surgical outcomes and methods to help recognize complications after transplant that can arise from these conditions.©RSNA, 2020.

As the treatment of ectopic pregnancy (EP) has shifted increasingly to medical therapies, the ultrasound (US) diagnosis of EP must necessarily favor specificity over sensitivity. Our review of peer learning cases of EP and early intrauterine pregnancies found several types of pitfalls and problems, which will be described in this essay. These issues include the following: differentiation of tubal EP from a corpus luteum by echogenicity relative to ovarian parenchyma, push technique, and claw sign; how to distinguish interstitial EP from eccentrically located intrauterine pregnancies (angular); use of trophoblastic flow in abnormal intrauterine locations to help identify cesarean scar or cervical implantations; recognition that hemoperitoneum without visualized EP may be due to EP or hemorrhagic cyst; and that distinguishing an abortion in progress from a pregnancy of unknown location may not always be possible and requires clinical follow-up. This essay will also illustrate the consensus terminology that our radiology department has developed in conjunction with our obstetrics and gynecology colleagues to communicate clear diagnoses and reduce the risk of misdiagnosis and adverse outcomes.

Hemangioma is the most common benign liver tumor and is frequently encountered as an incidental finding on imaging. The classic enhancement pattern of hemangioma is diagnostic on contrast-enhanced ultrasound (CEUS), and it follows the same pattern of enhancement on computed tomography and magnetic resonance imaging. However, there is a subset of hemangiomas that demonstrate atypical enhancement patterns on CEUS. The ability to recognize the different enhancement patterns and discern when additional imaging or biopsy may be necessary is essential to accurately interpret an atypical hemangioma on CEUS. This article reviews various enhancement patterns of hemangioma on CEUS to avoid pitfalls in characterization of focal liver lesions on CEUS.

Gallbladder polyps (GPs) are a common incidental finding on ultrasound; however, important differences in recommended management exist among professional society guidelines.An electronic survey was sent to 189 fellows of the Society of Radiologists in Ultrasound. Main outcomes included preferences and current practice patterns for evaluation, management, and surveillance of GPs as well as personal lifetime experience with gallbladder sonography and GPs.A total of 64 subjects (34%) with experience in gallbladder sonography completed the study. The estimated combined total number of gallbladder scans seen by the responders was 3,071,880. None of fellows had ever seen a pedunculated GP1 cm detected on ultrasound that was proven to be malignant at the time of detection or during subsequent follow-up. All of the fellows used size as a feature to stratify recommendations. The median size threshold currently used by Society of Radiologists in Ultrasound fellows for recommending ultrasound follow-up was 6 mm, and their preferred threshold was 7 mm. The median size threshold for recommending surgical consultation was 10 mm, and the preferred threshold was 10 mm. Wall thickening and shape were considered important factors by 76% and 67% of respondents, respectively.Society of Radiologists in Ultrasound fellows tend to provide recommendations most similar to the American College of Radiology and Canadian Association of Radiology guidelines for management of GPs. Many would prefer guidelines that result in fewer recommendations for follow-up and surgical consultation. Despite a substantial combined experience, this survey did not uncover any case of a small GP that was malignant.

In the adaptive immune system, V(D)J recombination initiates the production of a diverse antigen receptor repertoire in developing B and T cells. Recombination activating proteins, RAG1 and RAG2 (RAG1/2), catalyze V(D)J recombination by cleaving adjacent to recombination signal sequences (RSSs) that flank antigen receptor gene segments. Previous studies defined the consensus RSS as containing conserved heptamer and nonamer sequences separated by a less conserved 12 or 23 base-pair spacer sequence. However, many RSSs deviate from the consensus sequence. Here, we developed a cell-based, massively parallel V(D)J recombination assay to evaluate RAG1/2 activity on thousands of RSSs. We focused our study on the RSS heptamer and adjoining spacer region, as this region undergoes extensive conformational changes during RAG-mediated DNA cleavage. While the consensus heptamer sequence (CACAGTG) was marginally preferred, RAG1/2 was highly active on a wide range of non-consensus sequences. RAG1/2 generally preferred select purine/pyrimidine motifs that may accommodate heptamer unwinding in the RAG1/2 active site. Our results suggest RAG1/2 specificity for RSS heptamers is primarily dictated by DNA structural features dependent on purine/pyrimidine pattern, and to a lesser extent, RAG:RSS base-specific interactions. Further investigation of RAG1/2 specificity using this new approach will help elucidate the genetic instructions guiding V(D)J recombination.Summary StatementPartially conserved recombination signal sequences (RSSs) govern antigen receptor gene assembly during V(D)J recombination. Here, a massively parallel analysis of randomized RSSs reveals key attributes that allow DNA sequence diversity in the RAG1/2 active site and that contribute to the differential utilization of RSSs in endogenous V(D)J recombination. Overall, these results will assist identification of RAG1/2 off-target sites, which can drive leukemia cell transformation, as well as characterization of bona fide RSSs used to generate antigen receptor diversity.

Impaired tubal patency accounts for up to 35% of cases of subfer-tility and infertility. Hysterosalpingography (HSG) or hysterosal-pingo-contrast sonography (HyCoSy) represents a first-line test in evaluating fallopian tube patency. Despite the association of HSG with ionizing radiation, HSG is a reference standard in assessing fallopian tube patency and tubal conditions such as tubal occlusion, salpingitis isthmica nodosa, and hydrosalpinx. HSG is widely available and utilizes either a water-soluble contrast medium (WSCM) or an oil-soluble contrast medium (OSCM). Compared with WSCM, HSG with OSCM results in a higher incidence of non–in vitro fertilization pregnancies and, therefore, may be pre-ferred in women younger than 38 years with unexplained subfer-tility. HSG may also be helpful in assessment after sterilization or before fallopian tube recanalization. US-based tubal tests are free of ionizing radiation and include HyCoSy, with either air-saline or microbubble US contrast material, and hysterosalpingo-foam sonography (HyFoSy), a tubal patency test that utilizes a gel foam. A comprehensive US infertility evaluation of the pelvis and fallopian tubes can be achieved in one setting by adding coronal three-dimensional imaging of the uterus, saline infusion sonohysterogra-phy, and HyCoSy or HyFoSy to routine pelvic US. MR HSG and virtual CT HSG also depict tubal patency and uterine and adnexal pathologic conditions and may be considered in select patients. While laparoscopic chromopertubation remains the standard for tubal patency evaluation, its disadvantages are its invasiveness and cost. Knowledge of the different fallopian tube tests and radiologic appearance of normal and abnormal fallopian tubes results in fewer pitfalls, accurate interpretation, and optimal patient care.

Lab companies developed serology tests for antibody detection of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) with United States Food and Drug Administration (FDA) emergency use authorization. Antibody detection uses purified proteins of SARS-CoV-2 to determine antibody binding via enzyme-linked immunosorbent assay, chemiluminescent immunoassay (CLIA), or colloidal gold-based immunochromatographic assay. With the advent of coronavirus disease 2019 (COVID-19), nucleic acid amplification technology (NAAT) SARS-CoV-2 testing for active infection was not widely available to healthy, active-duty Soldiers. The purpose of this surveillance survey was to determine the prevalence of prior SARS-CoV-2 infection and symptoms of COVID-19 within a mechanized infantry brigade.Active-duty military Servicemembers (= 18 years) from a mechanized infantry brigade provided serum samples for testing for the Elecsys® Anti-SARS-CoV-2 qualitative antibody test from June to September 2020 at Joint Base Lewis McChord (JBLM). In addition, participants filled out a questionnaire for symptoms and exposure to COVID-19 from January to September 2020. The surveillance team collected and analyzed antibody testing results and questionnaires from participants for antibody positivity rates and symptom prevalence.A total of 264 participants were tested, with one (0.4%) participant testing positive for the SARS-CoV-2 antibody. On the questionnaire, 144 of 264 (54.5%) endorsed symptoms of COVID-19 from January to September 2020. The most common symptoms were headache (35%), rhinorrhea (34%), cough (35%), and sore throat (31%). A total of 31 respondents (12%) had been quarantined as a trace contact to a COVID-19 positive patient.While there are limitations inherent to SARS-CoV-2 antibody testing and the survey, prevalence of prior SARS-CoV-2 infection is low. In this sample, symptoms for COVID-19 were prevalent with significant days of duty lost. Prevalence of prior SARS-CoV-2 infection in this sample may be generalizable to the larger brigade. Prevalence of symptoms of possible COVID-19 are not generalizable to the larger brigade. There is utility to further studies of SARS-CoV-2 antibody prevalence in military populations for purposes of vaccination triaging and deployment readiness.

Ultrasound plays an essential role in the initial evaluation of patients with suspected or confirmed acute pancreatitis. In addition to evaluation of the pancreatic parenchyma, ultrasound is used for assessment of the gallbladder, biliary tree, peripancreatic tissues, and regional vascular structures. While enlarged and edematous pancreas are classic sonographic features of acute pancreatitis, the pancreas may appear sonographically normal in the setting of acute pancreatitis. Nonetheless, sonographic evaluation in this setting is valuable because assessment for etiologic factors such as gallstones or evidence of biliary obstruction are best performed with ultrasound. Complications of pancreatitis such as peripancreatic fluid collections, venous thrombosis, or arterial pseudoaneurysm can be identified with careful and focused ultrasound examination. Knowledge of various scanning techniques can help to mitigate some of the commonly encountered barriers to sonographic visualization of the pancreas and right upper quadrant structures. Ultrasound can also be used for guidance of percutaneous treatment such as drainage of fluid collections or pseudoaneurysm thrombosis. Difficulty in differentiating edematous from necrotizing pancreatitis can be mitigated with the use of contrast-enhanced ultrasound to assess pancreatic parenchymal enhancement.

The US Liver Imaging Reporting and Data System (LI-RADS) was released in 2017 and is the newest of the four American College of Radiology (ACR) LI-RADS algorithms. US LI-RADS provides standardized terminology, technical recommendations, and a reporting framework for US examinations performed for screening or surveillance in patients at risk for developing hepatocellular carcinoma (HCC). The appropriate patient population for screening and surveillance includes individuals who are at risk for developing HCC but do not have known or suspected cancer. This includes patients with cirrhosis from any cause and subsets of patients with chronic hepatitis B virus infection in the absence of cirrhosis. In an HCC screening or surveillance study, US LI-RADS recommends assigning two scores that apply to the entire study: the US category, which determines follow-up, and a visualization score, which communicates the expected level of sensitivity of the examination but does not affect management. Three US categories are possible: US-1 negative, a study with no evidence of HCC; US-2 subthreshold, a study in which an observation less than 10 mm is depicted that is not definitely benign; and US-3 positive, a study in which an observation greater than or equal to 10 mm or a new thrombus in vein is identified, for which diagnostic contrast material–enhanced imaging is recommended. Three visualization scores are possible: A (no or minimal limitations), B (moderate limitations), and C (severe limitations). (©)RSNA, 2019

In the context of chronic liver disease (CLD), sonographic features of hepatic steatosis, cirrhosis, and portal hypertension are discussed and examples are provided. The impact of CLD and hepatocellular carcinoma (HCC) is introduced, providing the rationale for a robust HCC screening and surveillance program for at-risk patients. The American College of Radiology Liver Imaging Reporting and Data System algorithms for screening and surveillance by ultrasound and for the definitive diagnosis of HCC by contrast-enhanced ultrasound are explained, with imaging examples provided. Contrast-enhanced ultrasound technique, limitations, and pitfalls also are introduced.

Ultrasound plays a vital role in the evaluation of patients with chronic liver disease and in hepatocellular carcinoma (HCC) surveillance in populations at risk for developing HCC. Semiannual ultrasound for HCC surveillance is universally recommended by all liver societies around the world. Advanced ultrasound techniques, such as elastography and contrast-enhanced ultrasound, offer additional benefits in imaging evaluation of chronic liver disease. Major benefits of ultrasound include its high safety profile and relatively low cost.

Acute liver failure (ALF) is a rare clinical entity with high morbidity and mortality frequently requiring liver transplantation for survival. Imaging, particularly with ultrasound, plays an important role, especially to distinguish patients with underlying chronic liver disease who have lower transplant priority. We discuss the clinical and imaging findings in the three subtypes of ALF using a multi-modality approach with an emphasis on ultrasound.

The V(D)J recombinase, composed of the recombination activating gene (RAG) proteins, RAG1 and RAG2, generate functional antigen receptor genes through the repeated generation of DNA double strand breaks and DNA repair. However, this process can lead to increased genomic instability particularly in the presence of excess DNA breaks. Previously, we showed in pre-B cells that full length RAG2, a nuclear protein, will export to the cytoplasm with DNA damage in an ATM-dependent manner with eventual recovery back into the nucleus following DNA repair. We propose that re-localization of RAG2 prevents RAG-mediated DNA cleavage in the presence of excess DNA ends. Here, by using fluorescently tagged RAG proteins, we show that DNA damage-induced export of the V(D)J recombinase can be recapitulated in non-lymphoid cells. Further, we determined that mutations in the intrinsically-disordered region of RAG2 have distinct effects on this process. Specifically, a basic region mutant of RAG2 (K/R 518–524 A) alters the localization pattern of the V(D)J recombinase, and yet its pre-DNA damage localization pattern is re-established upon DNA repair. Conversely, a T490A mutant blocks relocalization of RAG2 following genotoxic stress for both the single T490A mutant and the combined T490A/basic region mutant. Together, these results demonstrate the role of the intrinsically-disordered region in RAG2 in regulating the mobility and subcellular localization of the V(D)J recombinase upon cellular conditions that may be deemed too risky for continued DNA rearrangements. Supported by NIA T32AG052363, NIH AI128137, OCAST

Lesbian, gay, bisexual, and queer (LGBQ) students are a substantial minority group within U.S. elementary, middle, and high schools. Many LGBQ students face harassment and discrimination, which can contribute to educational and psychological problems. Teachers play key roles in students’ school experiences, and their attitudes about homosexuality can influence their behavior toward LGBQ students. The purpose of this study was to examine the prevalence of teachers’ positive and negative LGBQ-related attitudes, potential changes in attitudes over time, and demographic and social variables that may be related to teachers’ attitudes. This study uses data from 305 pre-kindergarten through 12th grade teachers, collected in waves 2006–2014 of the General Social Survey. Results indicate that teachers’ attitudes toward homosexuality have become more favorable over time; however, many teachers still hold negative attitudes. Just under half of teachers exhibited at least one negative LGBQ-related attitude. Age, political conservativeness, religious attendance, and carryover of religious beliefs were significantly associated with negative LGBQ attitudes. Teachers with a fundamentalist religious orientation tended to have more negative attitudes about homosexuality than teachers with more progressive religious orientations. Negative attitudes were more often found among teachers of color, compared to White teachers, and teachers in the South, Midwest, and Mountain regions tended toward more negative attitudes than teachers in the Northeast and Pacific regions. Teachers have an ethical responsibility to see that all students, regardless of sexual orientation, receive a quality education. Education and training are needed to address problematic attitudes that may negatively affect LGBQ students.

The purpose of this pictorial essay is to review different etiologies for lower extremity pain encountered on lower extremity venous sonography including acute deep venous thrombosis, chronic postthrombotic change, central venous disease, common arterial pathologies, and nonvascular abnormalities.

Given the high prevalence, increasing incidence, and significant morbidity and mortality related to hepatocellular carcinoma (HCC), a robust and cost-effective screening and surveillance program is needed. Most societies recommend ultrasound for HCC screening, despite lack of standardization in imaging acquisition, reporting content and language, and follow-up recommendations. The American College of Radiology Ultrasound Liver Imaging Reporting and Data System (US LI-RADS) fills this unmet need by providing standardization in the use of US in at-risk patients. It is anticipated that US LI-RADS will improve the performance of ultrasound for HCC screening and surveillance and unify management recommendations.

It is both challenging and desirable to have drug sensitizers released at acidic tumor pH for photodynamic therapy in cancer treatment. A pH-responsive carrier was prepared, in which fumed silica-attached 5,10,15,20-tetrakis(4-trimethylammoniophenyl)porphyrin (TTMAPP) was encapsulated into 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) nanocomposite liposomes. The sizes of agglomerates were determined by dynamic light scattering to be 115 nm for silica and 295 nm for silica-TTMAPP-DOPC liposomes. Morphological changes were also found in TEM images, showing liposome formation at pH 8.5 but collapse upon silanol protonation. TTMAPP release is enhanced from 13% at pH 7.5 to 80% at pH 2.3, as determined spectrophotometrically through dialysis membranes. Fluorescence emission of TTMAPP encapsulated in the dry film of liposomes was reduced to half at pH 8.6 when compared to that at pH 5.4, while the production of singlet oxygen was quintupled at pH 5.0 compared to pH 7.6. Upon treatment of human prostate cancer cells with liposomes containing 6.7 μM, 13 μM, 17 μM and 20 μM TTMAPP, the cell viabilities were determined to be 60%, 18%, 20% and 5% at pH 5.4; 58%, 30%, 25% and 10% at pH 6.3; and 90%, 82%, 68% and 35% at pH 7.4, respectively. Light-induced apoptosis in cancerous cells was only observed in the presence of liposomes at pH 6.3 and pH 5.4 but not at pH 7.4, as indicated by chromatin condensation.

Objectives: Adolescents in the United States face crucial sexual health behavior issues, including consequences of sexually transmitted infections and diseases, pregnancy, and sexual violence. Lesbian, gay, bisexual, and transgender youth are disproportionately affected by these issues. State policies about sex education in K-12 schools shape what is taught to students about sexual health. In this study, we analyzed the content of school-based sex education policies of all 50 states and focuses on sexual behaviors, relationships, and identities. Methods: Policies analyzed include state statutes, state board of education policies, and state department of education or public instruction curriculum standards. Data were analyzed using content analysis. Results: Most state policies emphasized abstinence from sexual behavior and did not require education about contraceptive and barrier methods. Few policies required detailed information about contraceptive and barrier methods to prevent pregnancy and sexually transmitted infections. Around half of states addressed relationship issues (ie, healthy relationships, sexual decision-making, and sexual violence); however, few states required content on communication about sexual consent. Eight state policies explicitly stigmatized homosexuality. Conversely, 12 states were inclusive of diverse sexual orientations and 7 states were inclusive of diverse gender identities. Conclusion: Sex education policies should be evidence-based and inclusive of sexual diversity.

Ultrasound is the imaging study of choice for detection and full characterization of early pregnancies based on its accuracy, low cost, safety profile, and abundant availability. This article reviews the goals and utility of first-trimester ultrasound in gestation localization, viability determination, and abnormal pregnancies, including ectopic implantation, retained products, and molar pregnancy.

V(D)J recombination is required to establish the diversity of antigen receptors in the adaptive immune system. Recombination activating gene 2 (RAG2), a protein subunit of the nuclear V(D)J recombinase, rearranges gene segments to generate functional genes that encode antigen receptors. Based on our previous results, we hypothesized that a negatively charged region (the acidic hinge) in RAG2 functions to regulate localization of the V(D)J recombinase with chromatin. To test this, we generated the acidic hinge mutant 1 (A1; D/E 370–383 A), acidic hinge mutant 2 (A2; D/E 404–410 A), and D400H (a known mutation that causes immunodeficiency) to determine impact on chromatin association and V(D)J recombination activity. Dynamics of RAG2 mobility with the chromatin were determined with fluorescence recovery after photobleaching (FRAP) experiments with stably expressed GFP-tagged wild type (WT) or mutant RAG2 in RAG2−/− pro-B cells. Changes in V(D)J recombination activity and in RAG2 localization was determined for cells expressing the WT versus mutant RAG2 proteins. FRAP experiments indicated that the acidic hinge mutants had more tightly bound interactions with chromatin, as compared to WT RAG2. A1 resulted in increased V(D)J recombination, whereas, A2 and D400H led to decreased V(D)J recombination. Interestingly, these results correlated with an increased and a decreased nuclear localization of A1 and A2, respectively, relative to WT RAG2. These results indicate that the acidic region has a role in the cellular localization of the V(D)J recombinase, affecting its recombination efficiency. However, D400H localized similarly to WT RAG2, indicating the residue has a more direct role in the nuclear function of the V(D)J recombinase.

V(D)J recombination by the RAG1 and RAG2 protein complex in developing lymphocytes includes DNA double strand break (DSB) intermediates. RAG2 undergoes export from the nucleus and enrichment at the centrosome minutes following production of DSBs by genotoxic stress, suggesting that RAG2 participates in cellular responses to DSBs such as those generated during V(D)J recombination. To determine the effect of RAG2 expression on cell viability following DSB generation, we measured pre-B cells that expressed either full length (FL) wild-type RAG2, or a T490A mutant of RAG2 that has increased stability and fails to undergo nuclear export following generation of DSBs. Each RAG2 construct was labeled with GFP at the N-terminus. Compared to the T490A mutant, cells expressing FL RAG2 exhibited elevated apoptosis by 24 h following irradiation, and this coincided with a greater amount of Caspase 3 cleavage measured in cell lysates. Pre-B cells expressing either RAG2 protein exhibited similar increases in phospho-p53 levels following irradiation. Interestingly, FL RAG2-expressing cells exhibited elevated division relative to the T490A clone beginning ~24 h following irradiation, as well as an increased percentage of cells proceeding through mitosis, suggesting an improved rate of recovery following the initial burst in apoptosis. Altogether, these data show that FL RAG2, but not its stable nuclear export-defective T490A mutant, participates in pre-B cell decisions between apoptosis versus DNA repair and cell cycle progression following DNA damage.

Development of the adaptive immune system is dependent on V(D)J recombination, which forms functional antigen receptor genes through rearrangement of component gene segments. The V(D)J recombinase, consisting of recombination-activating proteins RAG1 and RAG2, guides the initial DNA cleavage events to the recombination signal sequence (RSS), which flanks each gene segment. Although the enzymatic steps for RAG-mediated endonucleolytic activity was established over two decades ago, only recently have high resolution structural studies of the catalytically active core regions of the RAG proteins shed light on conformational requirements for the reaction. While outstanding questions remain, we have a clearer picture for how RAG proteins function in generating the diverse repertoires of antigen receptors, the underlying foundation of the adaptive immune system.

Infiltrative hepatocellular carcinoma (HCC) can be overlooked on imaging. Radiologists should have a high index of suspicion for this entity in patients with chronic liver disease. Careful evaluation of the portal vein may help the radiologist diagnose infiltrative HCC, due to the high association (68%-100%) of portal vein tumor thrombus with this condition. This article will review the imaging findings of infiltrative HCC, particularly its association with portal vein thrombus, and describe imaging pitfalls and mimickers.

Purpose The aim of this study was to evaluate the clinical performance of the ACR’s Ultrasound Liver Reporting and Data System (US LI-RADS™) for detecting hepatocellular carcinoma (HCC) in patients at high risk for HCC. Methods In this retrospective, multicenter study, 2,050 patients at high risk for HCC (1,078 men and 972 women; mean age, 57.7 years) at five sites in the United States had undergone screening liver ultrasound from January 2017 to February 2018, and US LI-RADS observation categories and visualization scores were assigned on a clinical basis. Ultrasound reports and patient records were retrospectively reviewed and follow-up imaging studies and/or pathologic reports recorded. Descriptive statistics were generated, and multivariate logistic regression analysis was used to analyze the relationship of clinical and reader-based predictors of limited visualization. Diagnostic performance data were calculated in the subset of patients with confirmatory testing. Results The most common indications for HCC screening were cirrhosis (n = 1,054 [51.4%]), noncirrhotic hepatitis B virus infection (n = 555 [27.1%]), and noncirrhotic hepatitis C virus infection (n = 234 [11.4%]). US LI-RADS observation categories assigned were US-1 (negative) in 90.4% (n = 1,854), US-2 (subthreshold) in 4.6% (n = 95), and US-3 (positive) in 4.9% (n = 101). Visualization scores were A (no or minimal limitations) in 76.8% (n = 1,575), B (moderate limitations) in 18.9% (n = 388), and C (severe limitations) in 4.2% (n = 87). Confirmatory tests, including multiphase contrast-enhanced CT or MRI (n = 331) or histopathology (n = 18), were available for 349 patients (17.0%). The sensitivity of US LI-RADS in this subset of patients was 82.4%, specificity was 74.2%, positive predictive value was 35.3%, and negative predictive value was 96.1%. Conclusions Approximately 90% of US LI-RADS screening examinations were negative, 5% subthreshold, and 5% positive. Visualization scores were diagnostically acceptable in the vast majority (>95%) of examinations. US LI-RADS emphasized sensitivity and negative predictive value, which are key characteristics of a screening test.

RAG2 of the V(D)J recombinase is essential for lymphocyte development. Within the RAG2 noncore region is a plant homeodomain (PHD) that interacts with the modified histone H3K4me3, and this interaction is important for relieving inhibition of the RAG recombinase for V(D)J recombination. However, the effect of the noncore region on RAG2 localization and dynamics in cell nuclei is poorly understood. Here, we used cell imaging to measure the effect of mutating the RAG2 noncore region on properties of the full length protein. We measured GFP-labeled full length RAG2 (FL), the RAG2 core region alone (Core), and a T490A mutant in the noncore region, which has unique regulatory properties. This showed that FL, T490A, and Core localized to nuclear domains that were adjacent to DAPI-rich heterochromatin, and that contained the active chromatin marker H3K4me3. Within the RAG2-enriched regions, T490A exhibited greater colocalization with H3K4me3 than either FL or Core. Furthermore, colocalization of H3K4me3 with FL and T490A, but not Core, increased in conditions that increased H3K4me3 levels. Superresolution imaging showed H3K4me3 was distributed as puncta that RAG2 abutted, and mobility measurements showed that T490A had a significantly lower rate of diffusion within the nucleus than either FL or Core proteins. Finally, mutating Trp453 of the T490A mutant (W453A,T490A), which blocks PHD-dependent interactions with H3K4me3, abolished the T490A-mediated increased colocalization with H3K4me3 and slower mobility compared to FL. Altogether, these data show that Thr490 in the noncore region modulates RAG2 localization and dynamics in the pre-B cell nucleus, such as by affecting RAG2 interactions with H3K4me3.

Drug-induced liver injury can lead to changes of the biliary tree that resemble sclerosing cholangitis. These changes can be seen on magnetic resonance cholangiopancreatography. Idiosyncratic drug-induced liver injury (DILI) has a variable presentation including cholestatic liver injury,1 in which case magnetic resonance imaging (MRI) is often performed to exclude pancreaticobiliary causes of obstruction. Sclerosing cholangitis (SC)-like changes on imaging have been described anecdotally with DILI.2,3 A recent study of 25 consecutive, unselected DILI patients found that 10% had SC-like changes on magnetic resonance cholangiopancreatography (MRCP).4 The aim of the current study was to identify the clinical features of patients enrolled in the U.S. Drug Induced Liver Injury Network (DILIN) prospective study who had SC-like changes on MRCP.

V(D)J recombination of lymphocyte antigen receptor genes occurs via the formation of DNA double strand breaks (DSBs) through the activity of RAG1 and RAG2. The co-existence of RAG-independent DNA DSBs generated by genotoxic stressors potentially increases the risk of incorrect repair and chromosomal abnormalities. However, it is not known whether cellular responses to DSBs by genotoxic stressors affect the RAG complex. Using cellular imaging and subcellular fractionation approaches, we show that formation of DSBs by treating cells with DNA damaging agents causes export of nuclear RAG2. Within the cytoplasm, RAG2 exhibited substantial enrichment at the centrosome. Further, RAG2 export was sensitive to inhibition of ATM, and was reversed following DNA repair. The core region of RAG2 was sufficient for export, but not centrosome targeting, and RAG2 export was blocked by mutation of Thr(490). In summary, DNA damage triggers relocalization of RAG2 from the nucleus to centrosomes, suggesting a novel mechanism for modulating cellular responses to DSBs in developing lymphocytes.

PURPOSE: Many students who are lesbian, gay, bisexual, transgender, or queer (LGBTQ) face hostile school environments that can negatively impact their mental health and education. This study involved a photovoice project where high school students from a Gay-Straight Alliance in the rural southeastern United States took photographs that depicted the issues LGBTQ students were facing and then exhibited their photographs and stories to individuals from the school system and local community to promote awareness, dialogue, and action. METHODS: 20 adults who attended the photovoiceexhibit responded to an online survey about their experiences with the intervention. RESULTS: 85% of adults reported that the interventionmade them think about issues they had not previously considered, including the struggles LGBTQ youth face, gender issues, and living in a rural community. Common emotions experienced at the interventionincluded feeling excited, concern for the youth, and proud of the youth. Further, 81% of the adults indicated that they would take action or behave differently as a result of the intervention, including supporting and affirming LGBTQ students, using gender-neutral and -inclusive language, and confronting bias in themselves and others. CONCLUSIONS: Photovoice is a promising strategy for LGBTQ students to activate adult allies in their community.

In the social amoeba Dictyostelium, Skp1 is hydroxylated on proline 143 and further modified by three cytosolic glycosyltransferases to yield an O-linked pentasaccharide that contributes to O2 regulation of development. Skp1 is an adapter in the Skp1/cullin1/F-box protein family of E3 ubiquitin ligases that targets specific proteins for polyubiquitination and subsequent proteasomal degradation. To investigate the biochemical consequences of glycosylation, untagged full-length Skp1 and several of its posttranslationally modified isoforms were expressed and purified to near homogeneity using recombinant and in vitro strategies. Interaction studies with the soluble mammalian F-box protein Fbs1/Fbg1/OCP1 revealed preferential binding to the glycosylated isoforms of Skp1. This difference correlated with the increased α-helical and decreased β-sheet content of glycosylated Skp1s based on circular dichroism and increased folding order based on small-angle X-ray scattering. A comparison of the molecular envelopes of fully glycosylated Skp1 and the apoprotein indicated that both isoforms exist as an antiparallel dimer that is more compact and extended in the glycosylated state. Analytical gel filtration and chemical cross-linking studies showed a growing tendency of less modified isoforms to dimerize. Considering that regions of free Skp1 are intrinsically disordered and Skp1 can adopt distinct folds when bound to F-box proteins, we propose that glycosylation, which occurs adjacent to the F-box binding site, influences the spectrum of energetically similar conformations that vary inversely in their propensity to dock with Fbs1 or another Skp1. Glycosylation may thus influence Skp1 function by modulating F-box protein binding in cells.

The continuing increase in antibiotic-resistant microorganisms is driving the search for new antibiotic targets and improved antimicrobial agents. Ketolides are semisynthetic derivatives of macrolide antibiotics, which are effective against certain resistant organisms. Solithromycin (CEM-101) is a novel fluoroketolide with improved antimicrobial effectiveness. This compound binds to the large 50S subunit of the ribosome and inhibits protein biosynthesis. Like other ketolides, it should impair bacterial ribosomal subunit formation. This mechanism of action was examined in strains of Streptococcus pneumoniae , Staphylococcus aureus , and Haemophilus influenzae . The mean 50% inhibitory concentrations (IC 50 s) for solithromycin inhibition of cell viability, protein synthesis, and growth rate were 7.5, 40, and 125 ng/ml for Streptococcus pneumoniae , Staphylococcus aureus , and Haemophilus influenzae , respectively. The net formation of the 50S subunit was reduced in all three organisms, with IC 50 s similar to those given above. The rates of 50S subunit formation measured by a pulse-chase labeling procedure were reduced by 75% in cells growing at the IC 50 of solithromycin. Turnover of 23S rRNA was stimulated by solithromycin as well. Solithromycin was found to be a particularly effective antimicrobial agent, with IC 50 s comparable to those of telithromycin and significantly better than those of azithromycin and clarithromycin in these three microorganisms.