Evolution of minimally invasive surgery for rectal cancer: update from the national cancer database.

BACKGROUND: As the use of minimally invasive techniques in colorectal surgery has become increasingly prevalent, concerns remain about the oncologic effectiveness and long-term outcomes of minimally invasive low anterior resection (MI-LAR) for the treatment of rectal cancer. STUDY DESIGN: The 2010-2015 National Cancer Database (NCDB) Participant Data Use File was queried for patients undergoing elective open LAR (OLAR) or MI-LAR for rectal adenocarcinoma. A 1:1 propensity match was performed on the basis of demographics, comorbidity, and tumor characteristics. Outcomes were compared between groups and Cox proportional hazard modeling was performed to identify independent predictors of mortality. A subset analysis was performed on high-volume academic centers. RESULTS: 35,809 patients undergoing LAR were identified of whom 18,265 (51.0%) underwent MI-LAR. After propensity matching, patients receiving MI-LAR were less likely to have a positive circumferential radial margin (CRM) (5.5% vs. 6.6%, p = 0.0094) or a positive distal margin (3.6% vs. 4.6%, p = 0.0022) and had decreased 90-day all-cause mortality (2.0% vs. 2.6%, p = 0.0238). MI-LAR resulted in decreased hospital length of stay (5 vs. 6 days, p < 0.0001) but a greater rate of 30-day readmission (7.6% vs. 6.5%, p = 0.0054). Long-term overall survival was improved with MI-LAR (79% vs. 76%, p < 0.0001). Cox proportional hazard modeling demonstrated a decreased risk of mortality with MI-LAR (HR 0.859, 95% CI 0.788-0.937). CONCLUSION: MI-LAR is associated with improvement in CRM clearance and long-term survival. In the hands of experienced surgeons with advanced laparoscopy skills, MI-LAR appears safe and effective technique for the management of rectal cancer.

Retrograde Transamputation Revascularization: A Case Report.

Below-knee amputation remains the most common level of amputation in patients with lower extremity gangrene and critical limb ischemia. Failure to heal, requiring additional operative debridement or conversion to an above-knee amputation remains a significant cause of patient morbidity. There remains no definitive diagnostic test that can accurately predict healing of the amputation site. We report a case utilizing a hybrid technique of retrograde transamputation revascularization via balloon angioplasty. This proximal, retrograde approach allows for relatively easy crossing and treatment of the infrainguinal chronic total occlusions (CTOs), improving arterial inflow for optimal wound healing.

Jejunal arterial access for retrograde mesenteric stenting.

Endovascular approaches have replaced open surgical revascularization in most patients with mesenteric ischemia; however, flush ostial occlusions may not be amenable to traditional antegrade access. Retrograde mesenteric stenting has been previously described, but this technique requires a formal laparotomy and dissection of the proximal superior mesenteric artery. We present here a modification of this technique that requires only a "mini-laparotomy" and no open vascular repair of the superior mesenteric artery as well as a review of our initial institutional experience with this procedure. Our approach differs from previously described work by minimizing mesenteric dissection, avoiding the need for repair of an arteriotomy, and limiting the size of the laparotomy incision in this population of profoundly comorbid patients.

Low mortality rates after endovascular aortic repair expand use to high-risk patients.

OBJECTIVE: The 2010 endovascular aneurysm repair (EVAR) trial 2 (EVAR 2) reported that patients with comorbidity profiles rendering them unfit for open aneurysm repair who underwent EVAR did not experience a survival advantage compared with those who did not undergo intervention. These patients experienced a 30-day mortality of 7.3%, whereas reports from similar cohorts reported far lower mortality rates. The primary objective of our study was to compare the incidence of 30-day mortality in low- and high-risk patients undergoing EVAR in a contemporary data set, using patient risk stratification criteria from EVAR 2. Secondarily, we sought to identify risk factors associated with a disproportionate contribution to 30-day mortality risk. METHODS: Data were obtained from the 2005 to 2013 American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) Participant Use Data Files (N = 24,813). Patients were included in the high-risk cohort with the presence of renal, respiratory, or cardiac preoperative criteria alone or in combination. Renal impairment criteria were defined as dialysis and creatinine concentration >2.26 mg/dL. Respiratory impairment criteria included history of chronic obstructive pulmonary disease and preoperative ventilator support. Cardiac impairment criteria included history of myocardial infarction, congestive heart failure, angina, and prior coronary intervention. Patient and procedural characteristics and 30-day postoperative outcomes were compared using Pearson χ2 tests for categorical variables and Wilcoxon rank sum tests for continuous variables. RESULTS: Among 24,813 patients undergoing EVAR, 12,043 (48%) patients were characterized as high risk (at least one impairment criterion); 12,770 (52%) patients were stratified as low risk. The 30-day mortality rate was 1.9% in the high-risk cohort compared with the 7.3% reported by EVAR 2, and it was higher in the high-risk cohort compared with the low-risk cohort (1.9% vs 0.9%; P < .001). Whereas the presence of each comorbidity increased the odds of 30-day mortality (respiratory odds ratio [OR], 1.62; 95% confidence interval [CI], 1.16-2.26; P = .005; cardiac OR, 1.55; 95% CI, 1.14-2.10; P = .005), the presence of renal criteria disproportionately increased the odds of mortality threefold (OR, 3.42; 95% CI, 2.31-5.09; P < .001). CONCLUSIONS: Contemporary 30-day mortality after EVAR in high-risk patients is substantially lower than that reported in the EVAR 2 trial. Whereas low- and high-risk stratification by current comorbidity criteria is appropriate, attention needs to be paid to disproportionate risk contribution from renal disease to mortality compared with cardiac and pulmonary comorbidities. Given the lower mortality risk than previously described, patients stratified as high risk should be thoughtfully considered for definitive EVAR.

Local excision results in comparable survival to radical resection for early-stage rectal carcinoid.

BACKGROUND: Controversy exists regarding current National Comprehensive Cancer Network guidelines, which recommend local excision for rectal carcinoids ≤2 cm and radical resection for tumors >2 cm. Given the limited data examining optimal surgical approach for these lesions, we queried a national database to determine the impact of extent of resection on survival. METHODS: Patients undergoing treatment for clinical stage I and II rectal carcinoid (RC) were identified from the National Cancer Data Base (1998-2012). The association between extent of surgery, tumor size, and the likelihood of pathologic lymph node positivity was examined. Kaplan-Meier analysis was used to compare overall survival. RESULTS: In total, 1900 patients were identified, of whom 1644 (86.5%) were treated with local excision, and 256 (13.5%) were treated with radical resection. A significant majority of patients with tumors ≤2.0 cm (89.0%) and nearly half with tumors 2.1-4.0 cm (44.8%) or >4.0 cm (45.8%) underwent local excision. Nodal positivity was correlated with tumor size (7.1% positivity with ≤2.0 cm tumors, 31.3% with 2.1-4.0 cm tumors, and 50.0% with >4 cm tumors). However, 5-y survival was equivalent between surgical approaches for tumors ≤2 cm (93.0% versus 93.0%) and tumors 2.1-4.0 cm (76.0% versus 76.0%). CONCLUSIONS: We demonstrate in early-stage RC that nearly half of intermediate and large tumors are being treated with local excision outside National Comprehensive Cancer Network guidelines. In addition, radical resection does not appear to be associated with improved overall survival for tumors of any size. These findings suggest that the preferred approach to early-stage RCs without aggressive biological characteristics is local excision due to the decreased morbidity and mortality versus radical resection.

Improved contemporary outcomes of liver transplantation for pediatric hepatoblastoma and hepatocellular carcinoma.

PURPOSE: Improvement in outcomes of LT for pediatric HB and HCC has been reported in small series. We analyzed national outcomes and changes in donor, recipient, and perioperative factors over time that may contribute to survival differences. METHODS: The UNOS database was queried for patients age <21 years that underwent LT for a primary diagnosis of HB or HCC (1987-2017). Subjects were divided into historic (transplant before 2010) and contemporary (transplant after 2010) cohorts. Baseline characteristics were compiled and examined. Survival was estimated using the Kaplan-Meier method and compared using the log-rank test. RESULTS: In total, 599 children with HB received LT (320 historic vs 279 contemporary). Concurrently, 141 children with HCC received LT (92 historic vs 49 contemporary). For both tumors, waitlist time decreased (HB 56.2 days historic vs 33.2 days contemporary, P = 0.017; HCC 189.3 days historic vs 71.7 days contemporary, P = 0.012). In the historic cohorts, patients with HB had a 1-year and 5-year OS of 84.6% and 75.1%, respectively. Survival for HCC was 84.4% and 59.9%, respectively. Outcomes improved in the contemporary era to 89.1% and 82.6% for HB, and 94.7% and 80.8% for HCC, respectively (both log-rank test P < 0.0001). CONCLUSION: Outcomes of LT have improved significantly, with contemporary survival now equivalent between these tumors and exceeding 80% 5-year OS. Future studies are needed to explore whether offering LT in patients that are resectable is justifiable.

Adjuvant Chemotherapy After Preoperative Chemoradiation Improves Survival in Patients With Locally Advanced Rectal Cancer.

BACKGROUND: Practice guidelines differ in their support of adjuvant chemotherapy use in patients who received preoperative chemoradiation for rectal cancer. OBJECTIVE: The purpose of this study was to evaluate the impact of adjuvant chemotherapy among patients with locally advanced rectal cancer who received neoadjuvant chemoradiation and surgery. DESIGN: This was a retrospective study. Multivariable Cox proportional hazard modeling was used to evaluate the adjusted survival differences. SETTINGS: Data were collected from the National Cancer Database. PATIENTS: Adults with pathologic stage II and III rectal adenocarcinoma who received neoadjuvant chemoradiation and surgery were included. MAIN OUTCOME MEASURES: Overall survival was measured. RESULTS: Among 12,696 patients included, 4023 (32%) received adjuvant chemotherapy. The use of adjuvant chemotherapy increased over the study period from 23% to 36%. Although older age and black race were associated with a lower likelihood of receiving adjuvant chemotherapy, patients with higher education level and stage III disease were more likely to receive adjuvant chemotherapy (all p < 0.05). At 7 years, overall survival was improved among patients who received adjuvant chemotherapy (60% vs. 55%; p < 0.001). After risk adjustment, the use of adjuvant chemotherapy was associated with improved survival (HR = 0.81 (95% CI, 0.72-0.91); p < 0.001). In the subgroup of patients with stage II disease, survival was also improved among patients who received adjuvant chemotherapy (68% vs 58% at 7 y; p < 0.001; HR = 0.70 (95% CI, 0.57-0.87); p = 0.002). Among patients with stage III disease, the use of adjuvant chemotherapy was associated with a smaller but persistent survival benefit (56% vs 51% at 7 y; p = 0.017; HR = 0.85 (95% CI, 0.74-0.98); p = 0.026). LIMITATIONS: The study was limited by its potential for selection bias and inability to compare specific chemotherapy regimens. CONCLUSIONS: The use of adjuvant chemotherapy among patients with rectal cancer who received preoperative chemoradiation conferred a survival benefit. This study emphasizes the importance of adjuvant chemotherapy in the management of rectal cancer and advocates for its increased use in the setting of neoadjuvant therapy. See Video Abstract at http://link.lww.com/DCR/A428.

Clinical Acuity Shorthand System: a standardized classification tool to facilitate handoffs.

BACKGROUND: The handoff of medical information from one provider to another can be inefficient and error prone, potentially undermining patient safety. Although several tools for structuring handoffs exist, none provide a brief, standardized framework for ensuring that patient acuity is efficiently and reliably communicated. We aim to introduce and perform initial testing of the Clinical Acuity Shorthand System (CLASS) (Copyright 2015, Duke University. All rights reserved.) for surgery, a patient classification tool intended to facilitate efficient communication of key patient information during handoffs. MATERIALS AND METHODS: Surgical trainees at a single center were asked to perform an exercise involving application of CLASS to 10 theoretical patient scenarios and to then complete a brief survey. Responses were scored based on similarity to target answers. Performance was evaluated overall and between groups of trainees. Time required to complete the exercise was also determined and perceived utility of the system was assessed based on survey responses. RESULTS: The study task was completed by 17 participants. Mean time to task completion was 10.3 ± 8.4 min. Accuracy was not decreased, and was in fact superior, in junior trainees. Most respondents indicated that such a system would be feasible and could prevent medical errors. CONCLUSIONS: CLASS is a novel system that can be learned quickly and implemented readily by trainees and can be used to convey patient information concisely and with acceptable fidelity regardless of level of training. Further study examining application of this system on clinical surgical services is warranted.

Renal medullary carcinoma: A national analysis of 159 patients.

BACKGROUND: Renal medullary carcinoma (RMC) is an aggressive malignancy seen predominantly in young males with sickle cell trait. RMC is poorly understood, with fewer than 220 cases described in the medical literature to date. We used a large national registry to define the typical presentation, treatments, and outcomes of this rare tumor. METHODS: The National Cancer Database was queried for patients under 40 years of age diagnosed with RMC from 1998 to 2011. An analysis of patient and tumor characteristics, treatment details, and overall survival (OS) was undertaken, and factors associated with mortality were identified using multivariable regression analysis. RESULTS: In total, 159 patients with RMC were identified, of whom a majority were male (71%), African American (87%), and had metastatic disease (71%). Median tumor size was 6 cm and median survival was 7.7 months. Most patients underwent surgery (60%) and chemotherapy (65%). Few patients received radiation (12%). Patients with metastatic disease had a significantly worse median survival (4.7 vs. 17.8 months, P < 0.001) and were less likely to receive surgery (42% vs. 91%, P < 0.001). Age and tumor size did not appear to impact OS. CONCLUSION: In the largest cohort to date of patients with RMC, we found a dismal median survival of less than 8 months. Age and tumor size were not associated with OS. Metastatic disease at presentation was the main negative prognostic indicator in RMC and was present in a majority of patients at the time of diagnosis.

How Can We Effectively Address the Medical and Psychological Concerns of Survivors of Pelvic Malignancies?

Sexual and urinary morbidities resulting from treatment of pelvic malignancies are common. These treatment sequelae are significantly bothersome to patients and challenging to address. Awareness of these complications is critical in order to properly counsel patients regarding potential side effects and to facilitate prompt diagnosis and management. Addressing these issues often necessitates a coordinated multidisciplinary approach; however, the effort required often translates into improvement in patient quality of life. Herein we review the sexual and urinary side effects that may arise during or after treatment of pelvic malignancies.

Children Receiving Hematopoietic Stem Cell Transplantation are at Increased Risk of Onychocryptosis Requiring Surgical Management.

PURPOSE: At our institution, a high proportion of children with onychocryptosis (ingrown toenail) requiring surgical intervention were noted to have a history of hematopoietic stem cell transplantation (HSCT). We analyzed the characteristics of patients who underwent surgical intervention for onychocryptosis and examined our institutional HSCT database to determine if an association exists between onychocryptosis and HSCT. MATERIALS AND METHODS: Surgical cases for onychocryptosis performed from 2000 to 2012 were identified. Nine demographic, clinical, and perioperative variables for both patients with and without prior HSCT were assessed. In a separate analysis, the institutional HSCT database was then queried to identify the prevalence and clinical characteristics associated with onychocryptosis after HSCT. RESULTS: We identified 17 children who had undergone surgical management of onychocryptosis, of which 8 (47.1%) had previous HSCT. Children who had undergone HSCT had an aggressive form of onychocryptosis with 50.0% having bilateral great toe and nail edge involvement and 37.5% having a recurrence. In HSCT cohort analysis of 1069 children, 91 (8.5%) had onychocryptosis. Male sex, non-black race, acute graft versus host disease, and increasing age at transplantation were independently associated with onychocryptosis. CONCLUSIONS: HSCT is strongly associated with onychocryptosis requiring surgical intervention. Children with a history of HSCT may also have more aggressive toenail disease, with higher rates of surgical intervention, bilateral ingrown toenails, recurrence, and need for return to the operating room. Clinicians should perform careful screening and early treatment in these patients.

Temporal Trends and Outcomes of Abdominal Aortic Aneurysm Care in the United States.

BACKGROUND: Endovascular aortic aneurysm repair (EVAR) has had a dynamic impact on abdominal aortic aneurysm (AAA) care, often supplanting open AAA repair (OAR). Accordingly, US AAA management is often highlighted by disparities in patient selection and guideline compliance. The purpose of this analysis was to define secular trends in AAA care. METHODS: The Society for Vascular Surgery Vascular Quality Initiative was queried for all EVARs and OARs (2011-2021). End points included procedure utilization, change in mortality, patient risk profile, Society for Vascular Surgery-endorsed diameter compliance, off-label EVAR use, cross-clamp location, blood loss, in-hospital complications, and post-EVAR surveillance missingness. Linear regression was used without risk adjustment for all end points except for mortality and complications, for which logistic regression with risk adjustment was used. RESULTS: In all, 66 609 EVARs (elective, 85% [n=55 805] and nonelective, 15% [n=9976]) and 13 818 OARs (elective, 70% [n=9706] and nonelective, 30% [n=4081]) were analyzed. Elective EVAR:OAR ratios were increased (0.2 per year [95% CI, 0.01-0.32]), while nonelective ratios were unchanged. Elective diameter threshold noncompliance decreased for OAR (24%→17%; P=0.01) but not EVAR (mean, 37%). Low-risk patients increasingly underwent elective repairs (EVAR, +0.4%per year [95% CI, 0.2-0.6]; OAR, +0.6 points per year [95% CI, 0.2-1.0]). Off-label EVAR frequency was unchanged (mean, 39%) but intraoperative complications decreased (0.5% per year [95% CI, 0.2-0.9]). OAR complexity increased reflecting greater suprarenal cross-clamp rates (0.4% per year [95% CI, 0.1-0.8]) and blood loss (33 mL/y [95% CI, 19-47]). In-hospital complications decreased for elective (0.7% per year [95% CI, 0.4-0.9]) and nonelective EVAR (1.7% per year [95% CI, 1.1-2.3]) but not OAR (mean, 42%). A 30-day mortality was unchanged for both elective OAR (mean, 4%) and EVAR (mean, 1%). Among nonelective OARs, an increase in both 30-day (0.8% per year [95% CI, 0.1-1.5]) and 1-year mortality (0.8% per year [95% CI, 0.3-1.6]) was observed. Postoperative EVAR surveillance acquisition decreased (67%→49%), while 1-year mortality among patients without imaging was 4-fold greater (9.2% versus imaging, 2.0%; odds ratio, 4.1 [95% CI, 3.8-4.3]; P<0.0001). CONCLUSIONS: There has been an increase in EVAR and a corresponding reduction in OAR across the United States, despite established concerns surrounding guideline adherence, reintervention, follow-up, and cost. Although EVAR morbidity has declined, OAR complication rates remain unchanged and unexpectedly high. Opportunities remain for improving AAA care delivery, patient and procedure selection, guideline compliance, and surveillance.

Rotavirus core shell subdomains involved in polymerase encapsidation into virus-like particles.

The triple-layered rotavirus virion encases an 11-segmented, dsRNA genome and 11-12 copies of the viral polymerase (VP1). VP1 transcribes and replicates the genome while tethered beneath the VP2 core shell. Genome replication (i.e. minus-strand RNA synthesis) by VP1 occurs in association with core assembly. During this process, VP2 directly engages VP1, thereby (i) packaging the polymerase into a nascent core and (ii) triggering the enzyme to initiate minus-strand RNA synthesis on bound plus-strand RNA templates. Recent work has shed light on VP2 regions important for VP1 enzymic activity. In the current study, we sought to investigate VP2 subdomains involved in the encapsidation of VP1 into recombinant virus-like particles (VLPs), which are formed of VP2 and the middle layer virion protein (VP6). We showed that strain SA11 VLPs efficiently encapsidated SA11 VP1, but not the genetically divergent Bristol VP1. VLPs made with an SA11 VP2 mutant lacking residues 1-10 of the amino-terminal domain (NTD) were still able to encapsidate VP1; however, removal of the entire NTD (residues 1-102) completely abolished polymerase packaging. We also showed that a chimeric VP2 protein containing the NTD and dimer-forming subdomain of strain Bristol VP2 can efficiently encapsidate SA11 VP1. These results suggest that the VP2 NTD and dimer-forming subdomain play important, albeit non-specific, roles in both VP1 packaging and activation. When combined with previous work, the results of this study support the notion that the same VP2 regions that engage VP1 during activation are also involved in packaging the enzyme into the core.

Muscle progenitor cells are required for skeletal muscle regeneration and prevention of adipogenesis after limb ischemia.

Skeletal muscle injury in peripheral artery disease (PAD) has been attributed to vascular insufficiency, however evidence has demonstrated that muscle cell responses play a role in determining outcomes in limb ischemia. Here, we demonstrate that genetic ablation of Pax7+ muscle progenitor cells (MPCs) in a model of hindlimb ischemia (HLI) inhibited muscle regeneration following ischemic injury, despite a lack of morphological or physiological changes in resting muscle. Compared to control mice (Pax7WT), the ischemic limb of Pax7-deficient mice (Pax7Δ) was unable to generate significant force 7 or 28 days after HLI. A significant increase in adipose was observed in the ischemic limb 28 days after HLI in Pax7Δ mice, which replaced functional muscle. Adipogenesis in Pax7Δ mice corresponded with a significant increase in PDGFRα+ fibro/adipogenic progenitors (FAPs). Inhibition of FAPs with batimastat decreased muscle adipose but increased fibrosis. In vitro, Pax7Δ MPCs failed to form myotubes but displayed increased adipogenesis. Skeletal muscle from patients with critical limb threatening ischemia displayed increased adipose in more ischemic regions of muscle, which corresponded with fewer satellite cells. Collectively, these data demonstrate that Pax7+ MPCs are required for muscle regeneration after ischemia and suggest that muscle regeneration may be an important therapeutic target in PAD.

A preponderance of gastrointestinal cancer patients transition into cachexia syndrome.

BACKGROUND: Cancer cachexia is frequently documented by self-reported, single time-point weight histories. This approach lacks the granularity needed to fully elucidate the progression of cachexia syndrome. This study aimed to longitudinally assess body weight changes pre- and post-cancer diagnosis in gastrointestinal (GI) cancer patients. METHODS: Body weights and relevant clinical data recorded in the electronic health record 12 months pre- and post-GI cancer (colorectal, gastroesophageal, hepatobiliary and pancreatic) diagnosis were extracted. Weight loss was categorized by the International Consensus Definition for cachexia. RESULTS: A total of 879 patients were included in the final cohort including patients diagnosed with colorectal (n = 317), hepatocellular (n = 185), biliary (n = 72), pancreatic (n = 186) or gastroesophageal (n = 119) cancer. Stage of disease was equally distributed. Patients without cachexia at diagnosis (n = 608) remained weight stable during the 12 months pre-diagnosis (+0.5 ± 0.5% body weight; P = 0.99). Patients with cachexia at diagnosis (n = 271) remained weight stable 6 to 12 months prior to diagnosis (+0.4 ± 0.8%; P > 0.9999) and lost 8.7 ± 0.6% (P < 0.0001) within the 6 months pre-diagnosis. Patients without cachexia at diagnosis lost more weight post-diagnosis (6.3 ± 0.6%) than patients with cachexia at diagnosis (4.7 ± 1.0%; P = 0.01). Pre-diagnosis weight trajectories did not differ between primary malignancies or stage of disease in patients without or with cachexia at diagnosis (all P ≥ 0.05). Post-diagnosis weight trajectories did differ by primary malignancy (P ≤ 0.0002) and stage (P < 0.0001). In both patients without and with cachexia at diagnosis, colorectal patients lost the least amount of weight post-diagnosis and gastroesophageal patients lost the most amount of weight post-diagnosis. Stage 4 patients without or with cachexia at diagnosis lost the most weight post-diagnosis (P ≤ 0.0003). Regardless of cachexia status at diagnosis, patients lost more weight when treated with systemic therapy (7.1 ± 0.7%; P < 0.0001; n = 419) or radiation therapy (8.4 ± 1.4%; P = 0.02; n = 116) compared to those who did not. Patients who did not have surgery lost more weight post-diagnosis (7.6 ± 1.1%; P < 0.0001; n = 355) compared to those who did have surgery. By 12 months post-diagnosis, 83% of the surviving GI cancer patients in this cohort had transitioned into cachexia syndrome. CONCLUSIONS: Significant weight loss in patients with GI cancer cachexia at diagnosis initiates at least 6 months prior to diagnosis, and most patients will transition into cachexia syndrome post-diagnosis, regardless of pre-diagnosis weight change and stage of disease. These findings punctuate the importance of weight surveillance in cancer detection and earlier palliative interventions post-diagnosis in the GI cancer patient population.

Adenosine deamination in human transcripts generates novel microRNA binding sites.

Animals regulate gene expression at multiple levels, contributing to the complexity of the proteome. Among these regulatory events are post-transcriptional gene silencing, mediated by small non-coding RNAs (e.g. microRNAs), and adenosine-to-inosine (A-to-I) editing, generated by adenosine deaminases that act on double-stranded RNA (ADAR). Recent data suggest that these regulatory processes are connected at a fundamental level. A-to-I editing can affect Drosha processing or directly alter the microRNA (miRNA) sequences responsible for mRNA targeting. Here, we analyzed the previously reported adenosine deaminations occurring in human cDNAs, and asked if there was a relationship between A-to-I editing events in the mRNA 3' untranslated regions (UTRs) and mRNA:miRNA binding. We find significant correlations between A-to-I editing and changes in miRNA complementarities. In all, over 3000 of the 12 723 distinct adenosine deaminations assessed were found to form 7-mer complementarities (known as seed matches) to a subset of human miRNAs. In 200 of the ESTs, we also noted editing within a specific 13 nucleotide motif. Strikingly, deamination of this motif simultaneously creates seed matches to three (otherwise unrelated) miRNAs. Our results suggest the creation of miRNA regulatory sites as a novel function for ADAR activity. Consequently, many miRNA target sites may only be identifiable through examining expressed sequences.

Artificial miRNAs mitigate shRNA-mediated toxicity in the brain: implications for the therapeutic development of RNAi.

Huntington's disease (HD) is a fatal, dominant neurodegenerative disease caused by a polyglutamine repeat expansion in exon 1 of the HD gene, which encodes the huntingtin protein. We and others have shown that RNAi is a candidate therapy for HD because expression of inhibitory RNAs targeting mutant human HD transgenes improved neuropathology and behavioral deficits in HD mouse models. Here, we developed shRNAs targeting conserved sequences in human HD and mouse HD homolog (HDh) mRNAs to initiate preclinical testing in a knockin mouse model of HD. We screened 35 shRNAs in vitro and subsequently narrowed our focus to three candidates for in vivo testing. Unexpectedly, two active shRNAs induced significant neurotoxicity in mouse striatum, although HDh mRNA expression was reduced to similar levels by all three. Additionally, a control shRNA containing mismatches also induced toxicity, although it did not reduce HDh mRNA expression. Interestingly, the toxic shRNAs generated higher antisense RNA levels, compared with the nontoxic shRNA. These results demonstrate that the robust levels of antisense RNAs emerging from shRNA expression systems can be problematic in the mouse brain. Importantly, when sequences that were toxic in the context of shRNAs were placed into artificial microRNA (miRNA) expression systems, molecular and neuropathological readouts of neurotoxicity were significantly attenuated without compromising mouse HDh silencing efficacy. Thus, miRNA-based approaches may provide more appropriate biological tools for expressing inhibitory RNAs in the brain, the implications of which are crucial to the development of RNAi for both basic biological and therapeutic applications.

Gonadal vein transposition is a safe and effective treatment of nutcracker syndrome.

BACKGROUND: Nutcracker syndrome (NCS) is a pelvic venous disorder that results from outflow obstruction of the left renal vein, most often due to a decreased aortomesenteric angle, leading to gonadal vein reflux, pain, and varices. Although a number of open and minimally invasive procedures to treat NCS have been described, the optimal management of this condition remains uncertain. To the best of our knowledge, we have presented the largest case series to date using gonadal vein transposition (GVT) to treat NCS. METHODS: Patients considered for intervention to treat NCS underwent a rigorous and standardized workup, including axial imaging studies, catheter-based diagnostic procedures, and urinalysis. GVT has been the institutional first-line treatment of NCS for appropriate patients. With institutional review board approval, a retrospective review of patients who had undergone GVT for NCS was conducted. RESULTS: From 2014 to 2019, 18 GVTs had been performed. Of the 18 patients, none had died or required reintervention, although 2 had required readmission. During a median follow-up of 178 days, complete symptom relief was achieved in 11 patients (61.1%), with 4 patients (22.2%) reporting partial symptom relief and 2 (11.1%) reporting transient symptom relief. CONCLUSIONS: GVT is a safe and effective procedure to treat NCS in appropriately selected patients with outcomes that compare favorably with those of other described procedures. Appropriate patient selection for this procedure is critical and requires a rigorous and standardized approach to diagnosis and management.

A Novel Model for a Student-Led Surgical Anatomy Seminar.

OBJECTIVE: We describe a novel educational model for a student-led anatomy interest group that utilizes an efficient method of knowledge sharing among peers in order to supplement the standard gross anatomy curriculum and expose medical students to advanced, surgically relevant anatomy. DESIGN: Student leaders of the Advanced Anatomy Interest Group compile a list of advanced anatomy "tidbits" related to a topic within a particular surgical specialty. Each medical student participant signs up for a different "tidbit" and prepares a short presentation. On meeting day, students present to the group. After each presentation, a surgical faculty moderator offers feedback and provides additional surgical perspective. SETTING: Duke University School of Medicine, Durham, NC, USA. PARTICIPANTS: Three third year medical student interest group leaders, 20 first through fourth year medical student participants, and 1 surgical faculty moderator. RESULTS: Twelve students presented an advanced anatomy tidbit, and 15 students responded to a 10-question postmeeting survey. Over 90% of respondents either agreed or strongly agreed that their understanding of surgically relevant anatomy had improved. Of those students who presented, 100% agreed or strongly agreed that their preparedness to briefly teach complex medical topics to colleagues had improved. Additionally, students reported increased interest in surgery and an improved perception of surgeons. CONCLUSIONS: This novel educational model appears to be an effective and efficient way to supplement the standard gross anatomy curriculum and expose medical students to advanced, surgically relevant anatomy. In addition, this model enables students to hone their presentation skills, gain experience teaching advanced medical concepts to peers, and develop relationships with surgical faculty. Surgical faculty are also not burdened with any preparatory responsibilities, making their participation more feasible. This model can serve as a template for medical students, house staff, and faculty interested in expanding anatomy education at their own institutions.

Integrity of the Mod(mdg4)-67.2 BTB domain is critical to insulator function in Drosophila melanogaster.

The Drosophila gypsy insulator contains binding sites for the Suppressor of Hairy-wing [Su(Hw)] protein. Enhancer and silencer blocking require Su(Hw) recruitment of Mod(mdg4)-67.2, a BTB/POZ domain protein that interacts with Su(Hw) through a carboxyl-terminal acidic domain. Here we conducted mutational analyses of the Mod(mdg4)-67.2 BTB domain. We demonstrate that this domain is essential for insulator function, in part through direction of protein dimerization. Our studies revealed the presence of a second domain (DD) that contributes to Mod(mdg4)-67.2 dimerization when the function of the BTB domain is compromised. Additionally, we demonstrate that mutations in amino acids of the charged pocket in the BTB domain that retain dimerization of the mutated protein cause a loss of insulator function. In these cases, the mutant proteins failed to localize to chromosomes, suggesting a role for the BTB domain in chromosome association. Interestingly, replacement of the Mod(mdg4)-67.2 BTB domain with the GAF BTB domain produced a nonfunctional protein. Taken together, these data suggest that the Mod(mdg4)-67.2 BTB domain confers novel activities to gypsy insulator function.