Stomal Stenosis After Continent Urinary Diversion in Bladder Exstrophy: Risk Factors and Management.

OBJECTIVE: To identify risk factors for stenosis and compare management strategies for stenosis etiology and to examine the efficacy of each approach. Patients with classic bladder exstrophy (CBE), a rare genitourinary malformation, may require construction of a continent urinary stoma (CUS) if incontinence persists. Stomal stenosis is a challenging complication as it is common, progressive and recurrent. METHODS: CBE patients who underwent CUS were retrospectively reviewed for risk factors for stenosis including stoma type, prior midline laparotomy number, and umbilicoplasty suture material. Stenosis etiology and management strategies were further reviewed. RESULTS: A total of 260 CBE patients underwent CUS creation. Stenosis developed in 65 patients (25.0%) at a median interval of 1.9 years. Etiology included scar contracture (n=41), keloid (n=17), and hypertrophic scar (n=7). Multifilament suture was the only variable associated with an increased risk of stenosis compared to monofilament suture (p=0.009). Almost all patients required surgical intervention. Most scar contractures underwent stomal incision with success in 100%. Hypertrophic scars and keloids responded best to excision with local tissue rearrangement (66.7%). At last follow-up, all patients achieved success. CONCLUSION: Stomal stenosis is common and challenging for the reconstructive surgeon. Strategies to prevent and effectively manage this are greatly desired. Use of multifilament suture for the umbilicoplasty increased stenosis perhaps from a greater inflammatory response and scarring, while monofilament suture may reduce its incidence. Stomal incision for treating scar contractures, and excision with local tissue rearrangement for hypertrophic scars and keloids may improve successful primary surgical intervention.

Testosterone Promotes Nerve Tethering and Acellular Biomaterial Perineural Fibrosis in a Rat Wound Repair Model.

Objective: Nerve scarring after traumatic or iatrogenic exposure can lead to impaired function and pain. Nerve-adjacent biomaterials promoting a regenerative tissue response may help reduce perineural fibrosis. Our prior work suggests that testosterone may promote fibrotic skin scarring, but it is unknown how testosterone alters nerve fibrosis or shifts the response to biomaterials. Approach: Sterilized Lewis rats received either testosterone cypionate (+T) or placebo (-T) biweekly. Fifteen days later, wounds were created over the sciatic nerve and covered with an acellular matrix (AM) or closed via primary closure (PC). At day 42, force gauge testing measured the force required to mobilize the nerve, and wound tissue was analyzed. Results: Nerve mobilization force was greater in +T versus -T wounds (p < 0.01). Nerves tore before gliding in 60% of +T versus 6% of -T rats. Epidermal gap (p < 0.01), scar width (p < 0.01), and cross-sectional scar tissue area (p = 0.02) were greater in +T versus -T rats. +T versus -T rats expressed less Col-3 (p = 0.02) and CD68 (p = 0.02). Nerve mobilization force trended nonsignificantly higher for PC versus AM wounds and for +T versus -T wounds within the AM cohort. Innovation: Testosterone increases nerve tethering in the wound healing milieu, altering repair and immune cell balances. Conclusion: Testosterone significantly increases the force required to mobilize nerves in wound beds and elevates histological markers of scarring, suggesting that testosterone-induced inflammation may increase perineural adhesion. Testosterone may reduce the potential anti-tethering protective effect of AM. Androgen receptor antagonism may represent a therapeutic target to reduce scar-related nerve morbidity.

Feasibility and clinical implementation of MRI-guided surface brachytherapy.

Purpose: Best practices for high-dose-rate surface applicator brachytherapy treatment (SABT) have long relied on computed tomography (CT)-based imaging to visualize diseased sites for treatment planning. Compared with magnetic resonance (MR)-based imaging, CT provides insufficient soft tissue contrast. This work described the feasibility of clinical implementation of MR-based imaging in SABT planning to provide individualized treatment optimization. Material and methods: A 3D-printed phantom was used to fit Freiberg flap-style (Elekta, The Netherlands) applicator. Images were taken using an optimized pointwise encoding time reduction with radial acquisition (PETRA) MR sequence for catheter visualization, and a helical CT scan to generate parallel treatment plans. This clinical study included three patients undergoing SABT for Dupuytren's contracture/palmar fascial fibromatosis imaged with the same modalities.SABT planning was performed in Oncentra Brachy (Elekta Brachytherapy, The Netherlands) treatment planning software. A geometric analysis was conducted by comparing CT-based digitization with MR-based digitization. CT and MR dwell positions underwent a rigid registration, and average Euclidean distances between dwell positions were calculated. A dosimetric comparison was performed, including point-based dose difference calculations and volumetric segmentations with Dice similarity coefficient (DSC) calculations. Results: Euclidean distances between dwell positions from CT-based and MR-based plans were on average 0.68 ±0.05 mm and 1.35 ±0.17 mm for the phantom and patients, respectively. The point dose difference calculations were on average 0.92% for the phantom and 1.98% for the patients. The D95 and D90 DSC calculations were both 97.9% for the phantom, and on average 93.6% and 94.2%, respectively, for the patients. Conclusions: The sub-millimeter accuracy of dwell positions and high DSC's (> 0.95) of the phantom demonstrated that digitization was clinically acceptable, and accurate treatment plans were produced using MR-only imaging. This novel approach, MRI-guided SABT, will lead to individualized prescriptions for potentially improved patient outcomes.

Optimizing prenatal diagnosis and referral of classic bladder exstrophy: Lessons from a single-institution experience.

INTRODUCTION: Classic bladder exstrophy (CBE) is a malformation of the genitourinary system that occurs due to failure of abdominal wall closure. Unlike other malformations of similar incidence, prenatal diagnosis of CBE relies on suggested, rather than formal, diagnostic criteria. OBJECTIVE: This report describes prenatal diagnosis of CBE in the largest single-institutional cohort to date and delineates key sonographic findings and protocols for specialist referral. MATERIALS AND METHODS: A single-institutional database was reviewed for CBE patients born since 2000. Data on screening ultrasound use, gestational age at ultrasound, and abnormal findings were extracted. Where possible, time of prenatal diagnosis (pre- or postnatal and gestational age), ultrasound findings and other imaging data, specialist referral, institution of birth and closure, and outcome of primary closure attempt were compared. RESULTS: Of 557 patients born with CBE between 2000 and 2022, 284 met inclusion criteria and complete data were available for 280 (229 born domestically and 51 born internationally) who were included for analysis. Abnormal sonography suggestive of CBE was present for 48% (n = 134) of patients, for whom absent bladder was the most common abnormal finding (76% [102/134]). Of domestic patients, 46% (n = 106) were diagnosed prenatally at a median gestational age of 22 weeks (inter-quartile range [IQR]: 20-24), and 14% (n = 32) underwent confirmatory fetal magnetic resonance imaging. Of domestic patients with abnormal prenatal findings, 75% (n = 80/106) consulted with maternal-fetal medicine and 58% (n = 62/106) consulted with pediatric urology. On univariate analysis, prenatal diagnosis was positively associated with primary repair at Association for the Bladder Exstrophy Community-recognized centers of excellence (54% vs. 38%, p = 0.02) and negatively associated with osteotomy at primary closure (41% vs 59%, p = 0.003) but not success of primary closure (74% vs. 82%, p = 0.07). DISCUSSION: Rates of prenatal diagnosis in this cohort were similar to previous reports of smaller cohorts. Diagnosis allows for comprehensive pre- and postnatal follow-up with a pediatric urologist, with implications on birth planning and decisions on termination of pregnancy. Because of the previously-reported association between exstrophy and in vitro fertilization, these pregnancies should undergo detailed sonography. Any nonvisualization of the fetal bladder should prompt a detailed exam, and any finding characteristic of bladder exstrophy warrants referral to pediatric urology. CONCLUSIONS: Although CBE is a rare disorder, it is underdiagnosed during pregnancy. Sonographers and obstetricians should be aware of characteristic findings and best practices following diagnosis. Early referral to pediatric urology and maternal-fetal medicine is important for counseling and postnatal planning.

Biological ammonium transporters: evolution and diversification.

Although ammonium is the preferred nitrogen source for microbes and plants, in animal cells it is a toxic product of nitrogen metabolism that needs to be excreted. Thus, ammonium movement across biological membranes, whether for uptake or excretion, is a fundamental and ubiquitous biological process catalysed by the superfamily of the Amt/Mep/Rh transporters. A remarkable feature of the Amt/Mep/Rh family is that they are ubiquitous and, despite sharing low amino acid sequence identity, are highly structurally conserved. Despite sharing a common structure, these proteins have become involved in a diverse range of physiological process spanning all domains of life, with reports describing their involvement in diverse biological processes being published regularly. In this context, we exhaustively present their range of biological roles across the domains of life and after explore current hypotheses concerning their evolution to help to understand how and why the conserved structure fulfils diverse physiological functions.

Interposing Rectus and Gracilis Muscle Flaps For Pelvic Reconstruction in Bladder Exstrophy After Bladder Neck Closure.

BACKGROUND: The exstrophy-epispadias complex is a spectrum of ventral wall malformations including classic bladder exstrophy (CBE) and cloacal exstrophy (CE). Patients undergo multiple soft-tissues procedures to achieve urinary continence. If unsuccessful bladder neck closure (BNC) is performed, muscle flaps may be used to reinforce BNC or afterwards for fistula reconstruction. In this study, patients reconstructed using a rectus abdominis or gracilis muscle flap were reviewed. METHODS: A retrospective cohort study of exstrophy-epispadias complex patients who underwent BNC and had a muscle fap was performed. Indication for flap use, surgical technique, risks for BNC failure including mucosal violations (MVs) were reviewed. MVs were prior bladder mucosa manipulation for exstrophy closure, repeat closure(s) and bladder neck reconstruction. Success was defined as BNC without fistula development. RESULTS: Thirty-four patients underwent reconstruction. Indications included during BNC (n=13), fistula closure after BNC (n=17), following BNC during open cystolithotomy (n=1) or fistula closure after open cystolithotomy (n=3). A vesicourethral fistula developed most frequently in CBE (88.9%) and vesicoperineal fistula in CE (87.5%). Thirty-three rectus flaps and 3 gracilis flap were used with success achieved in 97.1% and 66.7%, respectively. All 34 patients achieved success and 2 CE patients required a second flap. CONCLUSION: The rectus flap is preferred as it covers the antero-inferior bladder and pelvic floor to prevent urethral, cutaneous, and perineal fistula formation. The gracilis flap only reaches the pelvic floor to prevent urethral and perineal fistula development. Increased MVs, increase the risk of fistula formation and may influence the need for prophylactic flaps.

Perioperative management of primary classic bladder exstrophy: A single institutional pathway to success.

PURPOSE: Appropriate perioperative management is crucial in patients undergoing classic bladder exstrophy closure (CBE). Therefore, the authors sought to review their intra and postoperative management of patients with CBE undergoing primary closure and examine the impact of this pathway on patient outcomes. METHOD: A prospectively maintained institutional approved exstrophy-epispadias complex database was reviewed for patients with CBE who had undergone primary closure between 2016 and 2022 and whose closure was performed within one year of age. Electronic medical records for eligible patients were retrospectively reviewed to examine patient demographics, use of pelvic osteotomy, immobilization status, pediatric intensive care unit (PICU) admission and management, perioperative analgesia and sedation, nutritional support, drainage tubes, blood transfusions, antibiotic coverage, hospital length of stay, postoperative complications, and closure failure. RESULTS: A total of 25 patients were identified, 22 with CBE and 3 with variant CBE. Closure was performed at a median age of 84 days with patients ranging in age from 9 to 351 days. All patients underwent osteotomy and immobilization with modified Buck's traction and external fixation for a median duration of 41 days. A suprapubic tube was placed in all patients for a median duration of 46.5 days. All patients underwent PICU admission following closure for a median duration of 8 days. Ventilator support was required in 68 % of patients for a median of 3 days. Epidural analgesia was used in all patients and catheters were maintained for a median duration of 19 days. All patients received a blood transfusion over the course of their admission. Patient-controlled analgesia was used in most patients as an adjunct for a median duration of 38.5 days. Other commonly used analgesic adjuncts included acetaminophen, diazepam, clonidine, and dexmedetomidine. TPN was used in 80 % of patients for a median of 7 days with a return of oral feeding thereafter. Overall, the closure success rate in this cohort of patients was 100 %. DISCUSSION: The outcome of primary bladder closure can have inauspicious consequences that can affect a child's continence for years. The incidence of failed bladder closure can be minimized with the implementation of a detailed plan for immobilization, analgesia, and nutrition guided by an experienced multi-disciplinary team. CONCLUSION: We have identified several guiding principles for perioperative success in exstrophy patients at our center including Buck's traction with external fixation, provision of adequate postoperative analgesia and sedation, aggressive nutritional support, renal and bladder drainage, and robust antibacterial support. Our high success rate in managing this complex pathology demonstrates its validity and use as a pathway to success.

Changes in Quality of Life Among Collegiate Athletes During COVID-19.

BACKGROUND: The COVID-19 pandemic has had a significant effect on the mental health of athletes. How this has affected quality of life (QoL), specifically in the college population, is poorly defined. HYPOTHESIS: During the COVID-19 pandemic, the mental and physical QoL will have decreased in collegiate athletes as compared with before the pandemic. STUDY DESIGN: Cross-sectional study. LEVEL OF EVIDENCE: Level 3. METHODS: Division I athletes from a total of 23 varsity teams at a single institution completed surveys between 2018 and 2022. QoL was assessed using the Veterans RAND 12-Item Health Survey (VR-12). VR-12 scores were separated into mental component scores (MCS) and physical component scores (PCS). Separate linear mixed effects models evaluated changes in MCS and PCS from pre-COVID to during COVID overall, as well as differences in changes by sex and sport type (individual, team). RESULTS: For all athletes, the PCS increased (54.6 [95% CI 54.4-54.7] vs 55.1 [54.9-55.3]; P < 0.01) and the MCS decreased (55.2 [54.9-55.5] vs 53.5 [53.1-53.8]; P < 0.01) from pre-COVID to during COVID. When evaluating for sex, women demonstrated a greater increase in PCS (0.57 ± 0.22; P = 0.01) and greater decrease in MCS (1.06 ± 0.38; P < 0.01). With respect to sport type, individual sports demonstrated a greater decrease in MCS (1.46 ± 0.39; P < 0.01), but no interaction was identified for PCS (0.42 ± 0.23; P = 0.07). CONCLUSION: Collegiate athletes demonstrated a decrease in their self-reported mental QoL during the COVID-19 pandemic, as compared with before the pandemic. This effect was most evident in women and in individual sports. Athletes also reported an increase in physical QoL during COVID that was also larger in women, but not related to sport. CLINICAL RELEVANCE: This study demonstrates the impact of the COVID-19 pandemic on collegiate athletes' QoL, including negative effects on mental health. It also identifies cohorts of athletes (women, individual) who may be more significantly affected.

Biological ammonium transporters from the Amt/Mep/Rh superfamily: mechanism, energetics, and technical limitations.

The exchange of ammonium across cellular membranes is a fundamental process in all domains of life and is facilitated by the ubiquitous Amt/Mep/Rh transporter superfamily. Remarkably, despite a high structural conservation in all domains of life, these proteins have gained various biological functions during evolution. It is tempting to hypothesise that the physiological functions gained by these proteins may be explained at least in part by differences in the energetics of their translocation mechanisms. Therefore, in this review, we will explore our current knowledge of energetics of the Amt/Mep/Rh family, discuss variations in observations between different organisms, and highlight some technical drawbacks which have hampered effects at mechanistic characterisation. Through the review, we aim to provide a comprehensive overview of current understanding of the mechanism of transport of this unique and extraordinary Amt/Mep/Rh superfamily of ammonium transporters.

Multi-staged vs Single-staged Pelvic Osteotomy in the Modern Treatment of Cloacal Exstrophy: Bridging the Gap.

PURPOSE: Staged pelvic osteotomy has been shown in the past to be an effective tool in the closure of the extreme pubic diastasis of cloacal exstrophy. The authors sought to compare orthopedic complications between non-staged pelvic osteotomies and staged pelvic osteotomies in cloacal exstrophy. METHODS: A prospectively maintained exstrophy-epispadias complex database of 1510 patients was reviewed for cloacal exstrophy bladder closure events performed with osteotomy at the authors' institution. Bladder closure failure was defined as any fascial dehiscence, bladder prolapse, or vesicocutaneous fistula within one year of closure. There was a total of 172 cloacal exstrophy and cloacal exstrophy variant patients within the database and only closures at the authors' institution were included. RESULTS: 64 closure events fitting the inclusion criteria were identified in 61 unique patients. Staged osteotomy was performed in 42 closure events and non-staged in 22 closures. Complications occurred in 46/64 closure events, with 16 grade III/IV complications. There were no associations between staged osteotomy and overall complication or grade III/IV complications (p = 0.6344 and p = 0.1286, respectively). Of the 46 total complications, 12 were orthopedic complications with 6 complications being grade III/IV. Staged osteotomy closure events experienced 10/42 orthopedic complications while non-staged osteotomy closures experienced 2/22 orthopedic complications, however this did not reach significance (p = 0.1519). Of the 64 closure events, 57 resulted in successful closure with 6 failures and one closure with planned cystectomy. CONCLUSION: This study confirms, in a larger series, superior outcomes when using staged pelvic osteotomy in cloacal exstrophy bladder closure. Staged osteotomy was shown to be a safe alternative to non-staged osteotomy that can decrease the risk of closure failure in this group. Staged pelvic osteotomy should be considered in all patients undergoing cloacal exstrophy bladder closure. TYPE OF STUDY: Treatment study. LEVEL OF EVIDENCE: Level III.

Observer preference of artificial intelligence-generated versus clinical prostate contours for ultrasound-based high dose rate brachytherapy.

BACKGROUND: For trans-rectal ultrasound (TRUS)-based high dose rate (HDR) prostate brachytherapy, prostate contouring can be challenging due to artifacts from implanted needles, bleeding, and calcifications. PURPOSE: To evaluate the geometric accuracy and observer preference of an artificial intelligence (AI) algorithm for generating prostate contours on TRUS images with implanted needles. METHODS: We conducted a retrospective study of 150 patients, who underwent HDR brachytherapy. These patients were randomly divided into training (104), validation (26) and testing (20) sets. An AI algorithm was trained/validated utilizing the TRUS image and reference (clinical) contours. The algorithm then provided contours for the test set. For evaluation, we calculated the Dice coefficient between AI and reference prostate contours. We then presented AI and reference contours to eight clinician observers, and asked observers to select their preference. Observers were blinded to the source of contours. We calculated the percentage of cases in which observers preferred AI contours. Lastly, we evaluate whether the presence of AI contours improved the geometric accuracy of prostate contours provided by five resident observers for a 10-patient subset. RESULTS: The median Dice coefficient between AI and reference contours was 0.92 (IQR: 0.90-0.94). Observers preferred AI contours for a median of 57.5% (IQR: 47.5, 65.0) of the test cases. For resident observers, the presence of AI contours was associated with a 0.107 (95% CI: 0.086, 0.128; p < 0.001) improvement in Dice coefficient for the 10-patient subset. CONCLUSION: The AI algorithm provided high-quality prostate contours on TRUS with implanted needles. Further prospective study is needed to better understand how to incorporate AI prostate contours into the TRUS-based HDR brachytherapy workflow.

Monte Carlo model of a prototype flat-panel detector for multi-energy applications in radiotherapy.

BACKGROUND: The incorporation of multi-energy capabilities into radiotherapy flat-panel detectors offers advantages including enhanced soft tissue visualization by reduction of signal from overlapping anatomy such as bone in 2D image projections; creation of virtual monoenergetic images for 3D contrast enhancement, metal artefact reduction and direct acquisition of relative electron density. A novel dual-layer on-board imager offering dual energy processing capabilities is being designed. As opposed to other dual-energy implementation techniques which require separate acquisition with two different x-ray spectra, the dual-layer detector design enables simultaneous acquisition of high and low energy images with a single exposure. A computational framework is required to optimize the design parameters and evaluate detector performance for specific clinical applications. PURPOSE: In this study, we report on the development of a Monte Carlo (MC) model of the imager including model validation. METHODS: The stack-up of the dual-layer imager (DLI) was implemented in GEANT4 Application for Tomographic Emission (GATE). The DLI model has an active area of 43×43 cm2 , with top and bottom Cesium Iodide (CsI) scintillators of 600 and 800 µm thickness, respectively. Measurement of spatial resolution and imaging of dedicated multi-material dual-energy (DE) phantoms were used to validate the model. The modulation transfer function (MTF) of the detector was calculated for a 120 kVp x-ray spectrum using a 0.5 mm thick tantalum edge rotated by 2.5o . For imaging validation, the DE phantom was imaged using a 140 kVp x-ray spectrum. For both validation simulations, corresponding measurements were done using an initial prototype of the imager. Agreement between simulations and measurement was assessed using normalized root mean square error (NRMSE) and 1D profile difference for the MTF and phantom images respectively. Further comparison between measurement and simulation was made using virtual monoenergetic images (VMIs) generated from basis material images derived using precomputed look-up tables. RESULTS: The MTF of the bottom layer of the dual-layer model shows values decreasing more quickly with spatial frequency, compared to the top layer, due to the thicker bottom scintillator thickness and scatter from the top layer. A comparison with measurement shows NRMSE of 0.013 and 0.015 as well as identical MTF50 of 0.8 mm1 and 1.0 mm1 for the top and bottom layer respectively. For the DE imaging of the DE-phantom, although a maximum deviation of 3.3% is observed for the 10 mm aluminum and Teflon inserts at the top layer, the agreement for all other inserts is less than 2.2% of the measured value at both layers. Material decomposition of simulated scatter-free DE images gives an average accuracy in PMMA and aluminum composition of 4.9% and 10.3% for 11-30 mm PMMA and 1-10 mm aluminum objects respectively. A comparison of decomposed values using scatter containing measured and simulated DE images shows good agreement within statistical uncertainty. CONCLUSION: Validation using both MTF and phantom imaging shows good agreement between simulation and measurements. With the present configuration of the digital prototype, the model can generate material decomposed images and virtual monoenergetic images.

Thecal plate morphology, molecular phylogeny, and toxin analyses reveal two novel species of Alexandrium (Dinophyceae) and their potential for toxin production.

This study describes two novel species of marine dinophytes in the genus Alexandrium. Morphological characteristics and phylogenetic analyses support the placement of the new taxa, herein designated as Alexandrium limii sp. nov. and A. ogatae sp. nov. Alexandrium limii, a species closely related to A. taylorii, is distinguished by having a shorter 2'/4' suture length, narrower plates 1' and 6'', with larger length: width ratios, and by the position of the ventral pore (Vp). Alexandrium ogatae is distinguishable with its metasert plate 1' having almost parallel lateral margins, and by lacking a Vp. Production of paralytic shellfish toxins (PSTs), cycloimines, and goniodomins (GDs) in clonal cultures of A. ogatae, A. limii, and A. taylorii were examined analytically and the results showed that all strains contained GDs, with GDA as major variants (6-14 pg cell-1) for all strains except the Japanese strain of A. limii, which exclusively had a desmethyl variant of GDA (1.4-7.3 pg cell-1). None of the strains contained detectable levels of PSTs and cycloimines.

The Effects of Growth Hormone on Nerve Regeneration and Alloimmunity in Vascularized Composite Allotransplantation.

BACKGROUND: Poor outcomes in functional recovery following upper extremity transplantation are largely due to denervation-induced muscle atrophy that occurs during the prolonged period of nerve regeneration. Growth hormone (GH) has well-established trophic effects on neurons, myocytes, and Schwann cells and represents a promising therapeutic approach to address this challenge. This study sought to confirm the positive effects of GH treatment on nerve regeneration and functional recovery and to evaluate the effects of GH treatment on the immune response in the setting of vascularized composite allotransplantation. METHODS: Rats underwent orthotopic forelimb transplantation across a full MHC-mismatch and received either porcine-derived growth hormone or no treatment (n=18 per group). Functional recovery was measured using electrically-stimulated grip strength testing. Animals were monitored for clinical and subclinical signs of rejection. RESULTS: Neuromuscular junction reinnervation and grip strength were improved in GH-treated animals (p=0.005; p=0.08). No statistically significant differences were seen in muscle atrophy, degree of myelination, axon diameter, and axon counts between groups. The rates of clinical and histological rejection did not significantly differ among groups. CONCLUSIONS: Our findings alleviate concern for increased risk of transplant rejection during GH therapy and therefore support the translation of growth hormone as a therapeutic method to promote improved functional recovery in upper extremity transplantation.

Engineering a Biomimetic In Vitro Model of Bruch's Membrane Using Hagfish Slime Intermediate Filament Proteins.

Bruch's membrane resides in the subretinal tissue and regulates the flow of nutrients and waste between the retinal pigment epithelial (RPE) and vascular layers of the eye. With age, Bruch's membrane becomes thicker, stiffer, and less permeable, which impedes its function as a boundary layer in the subretina. These changes contribute to pathologies such as age-related macular degeneration (AMD). To better understand how aging in Bruch's membrane affects surrounding tissues and to determine the relationship between aging and disease, an in vitro model of Bruch's membrane is needed. An accurate model of Bruch's membrane must be a proteinaceous, semipermeable, and nonporous biomaterial with similar mechanical properties to in vivo conditions. Additionally, this model must support RPE cell growth. While models of subretinal tissue exist, they typically differ from in vivo Bruch's membrane in one or more of these properties. This study evaluates the capability of membranes created from recombinant hagfish intermediate filament (rHIF) proteins to accurately replicate Bruch's membrane in an in vitro model of the subretinal tissue. The physical characteristics of these rHIF membranes were evaluated using mechanical testing, permeability assays, brightfield microscopy, and scanning electron microscopy. The capacity of the membranes to support RPE cell culture was determined using brightfield and fluorescent microscopy, as well as immunocytochemical staining. This study demonstrates that rHIF protein membranes are an appropriate biomaterial to accurately mimic both healthy and aged Bruch's membrane for in vitro modeling of the subretinal tissue.

Prokaryotic ammonium transporters: what has three decades of research revealed?

The exchange of ammonium across cellular membranes is a fundamental process in all domains of life. In plants, bacteria and fungi, ammonium represents a vital source of nitrogen, which is scavenged from the external environment. In contrast, in animal cells ammonium is a cytotoxic metabolic waste product and must be excreted to prevent cell death. Transport of ammonium is facilitated by the ubiquitous Amt/Mep/Rh transporter superfamily. In addition to their function as transporters, Amt/Mep/Rh proteins play roles in a diverse array of biological processes and human physiopathology. Despite this clear physiological importance and medical relevance, the molecular mechanism of Amt/Mep/Rh proteins has remained elusive. Crystal structures of bacterial Amt/Rh proteins suggest electroneutral transport, whilst functional evidence supports an electrogenic mechanism. Here, focusing on bacterial members of the family, we summarize the structure of Amt/Rh proteins and what three decades of research tells us concerning the general mechanisms of ammonium translocation, in particular the possibility that the transport mechanism might differ in various members of the Amt/Mep/Rh superfamily.

Mucosal Violations and Their Effect on Successful Bladder Neck Closure in Cloacal Exstrophy.

BACKGROUND: Cloacal exstrophy (CE) is rare and challenging to reconstruct. In the majority of CE patients voided continence cannot be achieved and so patients often undergo bladder neck closure (BNC). Prior mucosal violations (MVs), a surgical event when the bladder mucosa was opened or closed, significantly predicted failed BNC in classic bladder exstrophy with an increased likelihood of failure after 3 or more MVs. The aim of this study was to assess predictors for failed BNC in CE. METHODS: CE patients who underwent BNC were reviewed for risk factors for failure including osteotomy use, successful primary closure, and number of MVs. Chi-squared and Fisher's exact tests were used for comparing baseline characteristics and surgical details. RESULTS: Thirty-five patients underwent BNC. Eleven patients (31.4%) failed BNC including a vesicoperineal fistula in nine, vesicourethral and vesicocutaneous fistula in one each. The fistula rate in patients with 2 or more MVs was 47.4% (p = 0.0252). Two patients subsequently developed a vesicocutaneous fistula after undergoing repeated cystolithotomies. A rectus abdominis or gracilis muscle flap were used to close the fistula in 11 and 2 patients, respectively. CONCLUSIONS: MVs have a greater impact in CE with an increased risk of failed BNC after 2 MVs. CE patients are most likely to develop a vesicoperineal fistula while a vesicocutaneous fistula is more likely after repeat cystolithotomy. A prophylactic muscle flap should be considered at time of BNC in patients with 2 or more MVs. LEVELS OF EVIDENCE: Prognosis Study, Level III.

Correlation of viral loads in disease transmission could affect early estimates of the reproduction number.

Early estimates of the transmission properties of a newly emerged pathogen are critical to an effective public health response, and are often based on limited outbreak data. Here, we use simulations to investigate how correlations between the viral load of cases in transmission chains can affect estimates of these fundamental transmission properties. Our computational model simulates a disease transmission mechanism in which the viral load of the infector at the time of transmission influences the infectiousness of the infectee. These correlations in transmission pairs produce a population-level convergence process during which the distributions of initial viral loads in each subsequent generation converge to a steady state. We find that outbreaks arising from index cases with low initial viral loads give rise to early estimates of transmission properties that could be misleading. These findings demonstrate the potential for transmission mechanisms to affect estimates of the transmission properties of newly emerged viruses in ways that could be operationally significant to a public health response.

Climate-smart forestry through innovative wood products and commercial afforestation and reforestation on marginal land.

Afforestation and reforestation (AR) on marginal land are nature-based solutions to climate change. There is a gap in understanding the climate mitigation potential of protection and commercial AR with different combinations of forest plantation management and wood utilization pathways. Here, we fill the gap using a dynamic, multiscale life cycle assessment to estimate one-century greenhouse gas (GHG) mitigation delivered by (both traditional and innovative) commercial and protection AR with different planting density and thinning regimes on marginal land in the southeastern United States. We found that innovative commercial AR generally mitigates more GHGs across 100 y (3.73 to 4.15 Giga tonnes of CO2 equivalent (Gt CO2e)) through cross-laminated timber (CLT) and biochar than protection AR (3.35 to 3.69 Gt CO2e) and commercial AR with traditional lumber production (3.17 to 3.51 Gt CO2e), especially in moderately cooler and dryer regions in this study with higher forest carbon yield, soil clay content, and CLT substitution. In a shorter timeframe (≤50 y), protection AR is likely to deliver higher GHG mitigation. On average, for the same wood product, low-density plantations without thinning and high-density plantations with thinning mitigate more life cycle GHGs and result in higher carbon stock than that of low-density with thinning plantations. Commercial AR increases the carbon stock of standing plantations, wood products, and biochar, but the increases have uneven spatial distributions. Georgia (0.38 Gt C), Alabama (0.28 Gt C), and North Carolina (0.13 Gt C) have the largest carbon stock increases that can be prioritized for innovative commercial AR projects on marginal land.

Bladder capacity and growth in classic bladder exstrophy: A novel predictive tool.

INTRODUCTION: Bladder capacity (BC) is an important metric in the management of patients with classic bladder exstrophy (CBE). BC is frequently used to determine eligibility for surgical continence procedures, such as bladder neck reconstruction (BNR), and is associated with the likelihood of achieving urinary continence. OBJECTIVE: To use readily available parameters to develop a nomogram that could be used by patients and pediatric urologists to predict BC in patients with CBE. STUDY DESIGN: An institutional database of CBE patients was reviewed for those who have undergone annual gravity cystogram 6 months after bladder closure. Candidate clinical predictors were used to model BC. Linear mixed effects models with random intercept and slope were used to construct models predicting log transformed BC and were compared with adjusted R2, Akaike Information Criterion (AIC), and cross-validated mean square error (MSE). Final model evaluated via K-fold cross-validation. Analyses were performed using R version 3.5.3 and the prediction tool was developed with ShinyR. RESULTS: In total, 369 patients (107 female, 262 male) with CBE had at least one BC measurement after bladder closure. Patients had a median of 3 annual measurements (range 1-10). The final nomogram includes outcome of primary closure, sex, log-transformed age at successful closure, time from successful closure, and interaction between outcome of primary closure and log-transformed age at successful closure as the fixed effects with random effect for patient and random slope for time since successful closure (Extended Summary). DISCUSSION: Using readily accessible patient and disease related information, the bladder capacity nomogram in this study provides a more accurate prediction of bladder capacity ahead of continence procedures when compared to the age-based Koff equation estimates. A multi-center study using this web-based CBE bladder growth nomogram (https://exstrophybladdergrowth.shinyapps.io/be_app/) will be needed for widespread application. CONCLUSION: Bladder capacity in those with CBE, while known to be influenced by a broad swath of intrinsic and extrinsic factors, may be modeled by the sex, outcome of primary bladder closure, age at successful bladder closure and age at evaluation.