TMEM161B regulates cerebral cortical gyration, Sonic Hedgehog signaling, and ciliary structure in the developing central nervous system.

Sonic hedgehog signaling regulates processes of embryonic development across multiple tissues, yet factors regulating context-specific Shh signaling remain poorly understood. Exome sequencing of families with polymicrogyria (disordered cortical folding) revealed multiple individuals with biallelic deleterious variants in TMEM161B, which encodes a multi-pass transmembrane protein of unknown function. Tmem161b null mice demonstrated holoprosencephaly, craniofacial midline defects, eye defects, and spinal cord patterning changes consistent with impaired Shh signaling, but were without limb defects, suggesting a CNS-specific role of Tmem161b. Tmem161b depletion impaired the response to Smoothened activation in vitro and disrupted cortical histogenesis in vivo in both mouse and ferret models, including leading to abnormal gyration in the ferret model. Tmem161b localizes non-exclusively to the primary cilium, and scanning electron microscopy revealed shortened, dysmorphic, and ballooned ventricular zone cilia in the Tmem161b null mouse, suggesting that the Shh-related phenotypes may reflect ciliary dysfunction. Our data identify TMEM161B as a regulator of cerebral cortical gyration, as involved in primary ciliary structure, as a regulator of Shh signaling, and further implicate Shh signaling in human gyral development.

Transcranial Low-Intensity Focused Ultrasound Stimulation of the Visual Thalamus Produces Long-Term Depression of Thalamocortical Synapses in the Adult Visual Cortex.

Transcranial focused ultrasound stimulation (tFUS) is a noninvasive neuromodulation technique, which can penetrate deeper and modulate neural activity with a greater spatial resolution (on the order of millimeters) than currently available noninvasive brain stimulation methods, such as transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS). While there are several studies demonstrating the ability of tFUS to modulate neuronal activity, it is unclear whether it can be used for producing long-term plasticity as needed to modify circuit function, especially in adult brain circuits with limited plasticity such as the thalamocortical synapses. Here we demonstrate that transcranial low-intensity focused ultrasound (LIFU) stimulation of the visual thalamus (dorsal lateral geniculate nucleus, dLGN), a deep brain structure, leads to NMDA receptor (NMDAR)-dependent long-term depression of its synaptic transmission onto layer 4 neurons in the primary visual cortex (V1) of adult mice of both sexes. This change is not accompanied by large increases in neuronal activity, as visualized using the cFos Targeted Recombination in Active Populations (cFosTRAP2) mouse line, or activation of microglia, which was assessed with IBA-1 staining. Using a model (SONIC) based on the neuronal intramembrane cavitation excitation (NICE) theory of ultrasound neuromodulation, we find that the predicted activity pattern of dLGN neurons upon sonication is state-dependent with a range of activity that falls within the parameter space conducive for inducing long-term synaptic depression. Our results suggest that noninvasive transcranial LIFU stimulation has a potential for recovering long-term plasticity of thalamocortical synapses in the postcritical period adult brain.

NSF DARE-transforming modeling in neurorehabilitation: perspectives and opportunities from US funding agencies.

In recognition of the importance and timeliness of computational models for accelerating progress in neurorehabilitation, the U.S. National Science Foundation (NSF) and the National Institutes of Health (NIH) sponsored a conference in March 2023 at the University of Southern California that drew global participation from engineers, scientists, clinicians, and trainees. This commentary highlights promising applications of computational models to understand neurorehabilitation ("Using computational models to understand complex mechanisms in neurorehabilitation" section), improve rehabilitation care in the context of digital twin frameworks ("Using computational models to improve delivery and implementation of rehabilitation care" section), and empower future interdisciplinary workforces to deliver higher-quality clinical care using computational models ("Using computational models in neurorehabilitation requires an interdisciplinary workforce" section). The authors describe near-term gaps and opportunities, all of which encourage interdisciplinary team science. Four major opportunities were identified including (1) deciphering the relationship between engineering figures of merit-a term commonly used by engineers to objectively quantify the performance of a device, system, method, or material relative to existing state of the art-and clinical outcome measures, (2) validating computational models from engineering and patient perspectives, (3) creating and curating datasets that are made publicly accessible, and (4) developing new transdisciplinary frameworks, theories, and models that incorporate the complexities of the nervous and musculoskeletal systems. This commentary summarizes U.S. funding opportunities by two Federal agencies that support computational research in neurorehabilitation. The NSF has funding programs that support high-risk/high-reward research proposals on computational methods in neurorehabilitation informed by theory- and data-driven approaches. The NIH supports the development of new interventions and therapies for a wide range of nervous system injuries and impairments informed by the field of computational modeling. The conference materials can be found at https://dare2023.usc.edu/ .

Daily Marijuana Use Predicts HIV Seroconversion Among Black Men Who Have Sex with Men and Transgender Women in Atlanta, GA.

We evaluated whether different types of substance use predicted HIV seroconversion among a cohort of 449 Black men who have sex with men (MSM) and transgender women (TGW). A community-based sample was recruited in Atlanta, GA between December 2012 and November 2014. Participants completed a survey and were tested for STIs (Chlamydia and gonorrhoeae using urine samples and rectal swabs) at baseline. HIV testing was conducted at 12-months post enrollment. Multivariable binary logistic regression was used to estimate adjusted odds ratios (aORs) and 95% confidence intervals (CI) for associations between substance use and HIV seroconversion. By 12-month follow-up, 5.3% (n = 24) of participants seroconverted. In multivariable analyses, daily marijuana use was positively associated with HIV seroconversion (aOR 3.07, 95% CI 1.11-8.48, P = 0.030). HIV incidence was high and daily marijuana use was associated with a more than threefold increased odds of HIV seroconversion among a community-based cohort of Black MSM and TGW.

RESUMEN: Evaluamos si diferentes tipos de uso de sustancias predijeron la seroconversión del VIH entre una cohorte de 449 hombres que tienen sexo con hombres (HSH) y mujeres transgénero (TGW) de raza negra. Se reclutó una cohorte en la comunidad en Atlanta, GA, entre diciembre de 2012 y noviembre de 2014. Los participantes completaron una encuesta y se les hizo una prueba de infecciones de transmisión sexual (clamidia y gonorrea usando muestras de orina e hisopos rectales) al inicio del estudio. Los participantes completaron una prueba del VIH al final del estudio. Se utilizó la regresión logística binaria multivariable para estimar proporciones de probabilidades ajustadas (aOR) y los intervalos de confianza (CI) del 95% para las asociaciones entre el uso de sustancias y la seroconversión del VIH. A los 12 meses de seguimiento, 5,3% (n = 24) de los participantes se seroconvirtieron. En análisis multivariable, el consumo diario de marijuana se asoció positivamente con la seroconversión del VIH (aOR 3.07, 95% CI 1.11­8.48, P = 0.030). La incidencia del VIH fue elevada y el uso diario de marijuana se asoció con un aumento de más de 3 veces en las probabilidades de seroconversión del VIH entre una cohorte de HSH y TGW de raza negra reclutado por la comunidad.

New and emerging therapies for the treatment of relapsed/refractory diffuse large B-cell lymphoma.

Diffuse large B-cell lymphoma (DLBCL) is the most common form of aggressive non-Hodgkin lymphoma. Approximately 40% of patients with DLBCL will experience disease relapse or will be refractory to first line chemoimmunotherapy, necessitating second-line salvage therapy. This has historically consisted of platinum-based chemotherapy regimens followed by autologous hematopoietic stem cell transplantation with curative intent for transplant-eligible patients or palliative chemotherapy for transplant-ineligible patients. In recent years there have been several new therapeutic agents approved for the treatment of relapsed/refractory DLBCL, thereby expanding the therapeutic landscape. These agents include polatuzumab vedotin, tafasitamab, loncastuximab tesirine, selinexor, and anti-CD19 chimeric antigen receptor T-cell therapies such as axicabtagene ciloleucel, tisagenlecleucel, and lisocabtagene maraleucel. This review summarizes the pharmacology, efficacy, safety, dosing, and administration of new agents recently approved for the treatment of relapsed/refractory DLBCL.

Outcomes of colostomy takedown following Hartmann's procedure: successful restoration of continuity comes with a high risk of morbidity.

AIM: Restoration of bowel continuity following a Hartmann's procedure is a major surgical undertaking associated with significant morbidity. The aim of this study was to review the authors' experience with Hartmann's reversal. METHOD: This was a retrospective review of consecutive patients from institutional databases who were selected to undergo open or laparoscopic Hartmann's reversal at two tertiary academic referral centres and a public safety net hospital (2010-2019). The main outcome measure was the rate of successful stoma reversal. Secondary outcomes included 30-day postoperative outcomes and procedural details. RESULTS: One hundred and fifty patients underwent attempted reversal during the study period, which was successful in all but three patients (98%). Patients were 59% Hispanic and 73% male, with a mean age of 48.7 ± 14.1 years, mean American Society of Anesthesiologists classification of 2.2 ± 0.6 and mean body mass index (BMI) of 28.6 ± 5.3 kg/m2 , with 39% of patients having a BMI > 30 kg/m2 . The mean time interval between the index procedure and reversal was 14.4 months, 53% of the index cases were performed at outside institutions and the most common index diagnoses were diverticulitis (54%), abdominal trauma (16%) and colorectal malignancy (15%). In 22% of cases a laparoscopic approach was used, with 42% of these requiring conversion to open. Proximal diverting stomas were created in 32 patients (21%), of which 94% were reversed. The overall morbidity rate was 54%, comprising ileus (32%), wound infection (15%) and anastomotic leak (6%), with a major morbidity rate (Clavien-Dindo ≥ 3) of 23%. CONCLUSION: Hartmann's reversal remains a highly morbid procedure. Our results suggest that operative candidates can be successfully reversed, but there is significant morbidity associated with restoration of intestinal continuity, particularly in obese patients. A laparoscopic approach may decrease morbidity in selected patients but such cases have a high conversion rate.

SMC5/6 is required for the formation of segregation-competent bivalent chromosomes during meiosis I in mouse oocytes.

SMC complexes include three major classes: cohesin, condensin and SMC5/6. However, the localization pattern and genetic requirements for the SMC5/6 complex during mammalian oogenesis have not previously been examined. In mouse oocytes, the SMC5/6 complex is enriched at the pericentromeric heterochromatin, and also localizes along chromosome arms during meiosis. The infertility phenotypes of females with a Zp3-Cre-driven conditional knockout (cKO) of Smc5 demonstrated that maternally expressed SMC5 protein is essential for early embryogenesis. Interestingly, protein levels of SMC5/6 complex components in oocytes decline as wild-type females age. When SMC5/6 complexes were completely absent in oocytes during meiotic resumption, homologous chromosomes failed to segregate accurately during meiosis I. Despite what appears to be an inability to resolve concatenation between chromosomes during meiosis, localization of topoisomerase IIα to bivalents was not affected; however, localization of condensin along the chromosome axes was perturbed. Taken together, these data demonstrate that the SMC5/6 complex is essential for the formation of segregation-competent bivalents during meiosis I, and findings suggest that age-dependent depletion of the SMC5/6 complex in oocytes could contribute to increased incidence of oocyte aneuploidy and spontaneous abortion in aging females.

The Eya1 Phosphatase Mediates Shh-Driven Symmetric Cell Division of Cerebellar Granule Cell Precursors.

During neural development, stem and precursor cells can divide either symmetrically or asymmetrically. The transition between symmetric and asymmetric cell divisions is a major determinant of precursor cell expansion and neural differentiation, but the underlying mechanisms that regulate this transition are not well understood. Here, we identify the Sonic hedgehog (Shh) pathway as a critical determinant regulating the mode of division of cerebellar granule cell precursors (GCPs). Using partial gain and loss of function mutations within the Shh pathway, we show that pathway activation determines spindle orientation of GCPs, and that mitotic spindle orientation correlates with the mode of division. Mechanistically, we show that the phosphatase Eya1 is essential for implementing Shh-dependent GCP spindle orientation. We identify atypical protein kinase C (aPKC) as a direct target of Eya1 activity and show that Eya1 dephosphorylates a critical threonine (T410) in the activation loop. Thus, Eya1 inactivates aPKC, resulting in reduced phosphorylation of Numb and other components that regulate the mode of division. This Eya1-dependent cascade is critical in linking spindle orientation, cell cycle exit and terminal differentiation. Together these findings demonstrate that a Shh-Eya1 regulatory axis selectively promotes symmetric cell divisions during cerebellar development by coordinating spindle orientation and cell fate determinants.

Cognitive swarming in complex environments with attractor dynamics and oscillatory computing.

Neurobiological theories of spatial cognition developed with respect to recording data from relatively small and/or simplistic environments compared to animals' natural habitats. It has been unclear how to extend theoretical models to large or complex spaces. Complementarily, in autonomous systems technology, applications have been growing for distributed control methods that scale to large numbers of low-footprint mobile platforms. Animals and many-robot groups must solve common problems of navigating complex and uncertain environments. Here, we introduce the NeuroSwarms control framework to investigate whether adaptive, autonomous swarm control of minimal artificial agents can be achieved by direct analogy to neural circuits of rodent spatial cognition. NeuroSwarms analogizes agents to neurons and swarming groups to recurrent networks. We implemented neuron-like agent interactions in which mutually visible agents operate as if they were reciprocally connected place cells in an attractor network. We attributed a phase state to agents to enable patterns of oscillatory synchronization similar to hippocampal models of theta-rhythmic (5-12 Hz) sequence generation. We demonstrate that multi-agent swarming and reward-approach dynamics can be expressed as a mobile form of Hebbian learning and that NeuroSwarms supports a single-entity paradigm that directly informs theoretical models of animal cognition. We present emergent behaviors including phase-organized rings and trajectory sequences that interact with environmental cues and geometry in large, fragmented mazes. Thus, NeuroSwarms is a model artificial spatial system that integrates autonomous control and theoretical neuroscience to potentially uncover common principles to advance both domains.

Achieving Opioid-Free Major Colorectal Surgery: Is It Possible?

INTRODUCTION: Opioid analgesia remains the mainstay of postoperative pain management strategies despite being associated with many adverse effects. A specific opioid-free protocol was designed to limit opioid usage. OBJECTIVE: The aim of the study was to audit the opioid-free rate within this protocol and to identify factors that might contribute to opioid-free surgery. METHODS: A retrospective study of all elective patients receiving abdominal colorectal surgery at the Center for Colon and Rectal Surgery at AdventHealth over 6 months was performed. Data on demographics, indications, perioperative management, outcomes, and inpatient and outpatient analgesic requirements were collected with subsequent analysis. RESULTS: A total of 303 consecutive patient records were analyzed. Approximately two-thirds (67.7%) of patients did not receive narcotics once they left the postanesthesia care unit as an inpatient. One-third of patients (32.0%) did not receive narcotic analgesia within 30 days of surgery as an outpatient. Patients in the opioid-free cohort were significantly older and had a malignant indication, less perioperative morbidity, and a shorter length of stay. CONCLUSIONS: Our study demonstrates that opioid-free analgesia is indeed possible in major colorectal surgery. Study limitations include its retrospective nature and that it is from a single institution. Despite these limitations, this study provides proof of concept that opioid-free colorectal surgery is possible within a specific protocol.

Technical feasibility of umbilical cannulation in midgestation lambs supported by the EXTra-uterine Environment for Neonatal Development (EXTEND).

EXTEND (EXTra-uterine Environment for Neonatal Development) is a novel system for supporting extremely premature infants that replicates in utero conditions by maintaining a sterile fluid environment and providing gas exchange via a pumpless arteriovenous oxygenator circuit connected to the umbilical vessels. Target gestational age (GA) for EXTEND support in human infants is 23-27 weeks, when immature lungs are most susceptible to injury in the setting of air ventilation. We previously demonstrated physiologic support of premature lambs cannulated at 105-117 days GA (lungs developmentally analogous to the 23-27 week GA human infant) for up to 28 days on EXTEND. In the present study, we sought to determine the technical feasibility of umbilical vessel cannulation in 85-96 days GA lambs delivered to EXTEND at weights equivalent to the 23-27 week GA human infant (500-850 g). Five preterm lambs were cannulated at 85-96 days GA (term 145 days) and supported on EXTEND for 4-7 days. All lambs underwent umbilical artery and umbilical vein cannulation. Circuit flows and pressures were monitored continuously, and blood gases were obtained at regular intervals for assessment of oxygen parameters. Systemic pH and lactate were measured at least once daily. Mean body weight at cannulation was 641 ± 71 g (range 480-850 g). All lambs were cannulated successfully (cannula size varied from 8 to 12 Fr), and mean survival on EXTEND was 140 ± 7 hours. Mean circuit flow was 213 ± 15 mL/kg*min, mean pH was 7.37 ± 0.01, and mean lactate was 1.6 ± 0.2 mmol/L. During the initial 120 hours after EXTEND cannulation, there were no significant differences between 85-96 days GA lambs and 105-117 days GA lambs in weight-adjusted circuit flows, oxygen delivery, pH, or lactate levels. This study demonstrates successful umbilical cord cannulation and adequate circuit flows and oxygen delivery in midgestation lambs size-matched to the 23-27 week GA human fetus, which represents an important step in the translation of EXTEND to clinical practice.

Chronically Hypoxic Fetal Lambs Supported by an Extra-Uterine Device Exhibit Mitochondrial Dysfunction and Elevations of Hypoxia Inducible Factor 1-Alpha.

INTRODUCTION: We have recently developed an extra-uterine environment for neonatal development (EXTEND) capable of supporting premature fetal lambs and have been able to replicate hypoxic in utero conditions by controlling fetal oxygen delivery. In this study, we investigated the fetal mitochondrial response to hypoxia. METHODS: Eight premature fetal lambs were delivered via hysterotomy and transitioned to extra-uterine support for 3 weeks. The lambs were divided into 2 groups: normoxic fetuses which maintained physiologic oxygen delivery and hypoxic fetuses in which oxygen delivery was significantly reduced. Control fetuses were delivered via hysterotomy but not cannulated. Measurements of mitochondrial membrane potential (MMP) were performed in peripheral blood mononuclear cells. RESULTS: There were no significant differences in MMP between normoxic EXTEND fetuses and controls. Hypoxic fetuses had significantly more depolarized mitochondria compared to normoxic fetuses overall, and these changes were specifically appreciated in weeks 1 and 2, but not by week 3. Hypoxic fetuses had significantly elevated levels of HIF-1α compared to normoxic fetuses in the first 2 weeks. DISCUSSION: Normoxic fetal lambs supported by EXTEND demonstrate normal mitochondrial function as evidenced by equivalent membrane potentials compared to control fetuses. Hypoxic fetuses exhibit mitochondrial dysfunction, though they do show evidence of adaptation after 3 weeks of hypoxic exposure.

Premature Lambs Exhibit Normal Mitochondrial Respiration after Long-Term Extrauterine Support.

BACKGROUND: In an effort to mitigate the major morbidities and mortality associated with extreme prematurity, we have developed an EXTrauterine Environment for Neonatal Development (EXTEND) designed to provide physiologic support of extremely premature infants. OBJECTIVES: We have previously shown that long-term, physiologic support of premature fetal lambs is possible with EXTEND, but in this study, we sought to demonstrate bioenergetic equipoise at the tissue level. METHODS: Four premature fetal lambs were delivered by hysterotomy at gestational ages (GA) of 105-107 days (term ∼145 days), cannulated via the umbilical vessels, and transitioned to support on EXTEND for 3-4 weeks. Five control fetuses were age-matched to the GA of experimental fetuses at the time of study end (128-134 days GA) and immediately sacrificed after hysterotomy. Mitochondria were isolated from the heart, liver, kidney, and skeletal muscle of fetuses at the time of sacrifice, and oxygen consumption rates (OCRs) were measured. RESULTS: There were no differences in basal mitochondrial OCR between EXTEND and control fetuses for heart, kidney, or skeletal muscle. For liver, the basal OCR was higher in EXTEND fetuses compared to controls. There were no differences in physiologic maximal OCR or reserve capacity for any tissue analyzed. CONCLUSIONS: Fetal lambs supported by EXTEND demonstrate physiologic mitochondrial function as evidenced by adequate basal and physiologic maximal cellular respiration as well as preserved reserve capacity.

Erythropoietin Prevents Anemia and Transfusions in Extremely Premature Lambs Supported by an EXTrauterine Environment for Neonatal Development (EXTEND).

BACKGROUND: We recently developed an EXTrauterine Environment for Neonatal Development (EXTEND) that provides physiologic support for premature lambs. Here, we assess the efficacy of exogenous erythropoietin (EPO) to prevent anemia and transfusions on EXTEND. MATERIALS AND METHODS: Lambs were cannulated at 0.7 gestation and supported on EXTEND for up to 4 weeks. The lambs were divided into three groups: (1) No EPO, (2) Low EPO (300 U kg-1 per day), and (3) High EPO (800 U kg-1 per day). Daily hematocrit and weekly complete blood count were assessed. RESULTS: The mean percentage change in hematocrit from baseline was significantly different between the groups (No EPO -23.6 ± 7.8% vs. Low EPO -16.6 ± 6.4% vs. High EPO +2.6 ± 6.6%; p = 0.02). This occurred despite a greater median number of blood transfusions in the No EPO group (5 vs. 1 vs. 0; p = 0.02). EPO administration was associated with a higher mean corpuscular volume (MCV; p < 0.01) and reticulocyte count (p = 0.02). The High EPO group was comparable to in utero control fetuses with respect to hematocrit (p = 0.49), MCV (p = 0.24), and reticulocyte count (p = 0.68). CONCLUSIONS: EPO (800 U kg-1 per day) prevents anemia, eliminates transfusions, and restores normal red blood cell indices in premature lambs supported by EXTEND.

Umbilical cannulation optimizes circuit flows in premature lambs supported by the EXTra-uterine Environment for Neonatal Development (EXTEND).

KEY POINTS: Bronchopulmonary dysplasia is a disease of extreme prematurity that occurs when the immature lung is exposed to gas ventilation. We designed a novel 'artificial womb' system for supporting extreme premature lambs (called EXTEND) that obviates gas ventilation by providing oxygen via a pumpless arteriovenous circuit with the lamb submerged in sterile artificial amniotic fluid. In the present study, we compare different arteriovenous cannulation strategies on EXTEND, including carotid artery/jugular vein (CA/JV), carotid artery/umbilical vein (CA/UV) and umbilical artery/umbilical vein (UA/UV). Compared to CA/JV and CA/UV cannulation, UA/UV cannulation provided significantly higher, physiological blood flows to the oxygenator, minimized flow interruptions and supported significantly longer circuit runs (up to 4 weeks). Physiological circuit blood flow in UA/UV lambs made possible normal levels of oxygen delivery, which is a critical step toward the clinical application of artificial womb technology. ABSTRACT: EXTEND (EXTra-uterine Environment for Neonatal Development) is a novel system that promotes physiological development by maintaining the premature lamb in a sterile fluid environment and providing gas exchange via a pumpless arteriovenous oxygenator circuit. During the development of EXTEND, different cannulation strategies evolved with the aim of improving circuit flow. The present study examines how different cannulation strategies affect EXTEND circuit haemodynamics in extreme premature lambs. Seventeen premature lambs were cannulated at gestational ages 105-117 days (term 145-150 days) and supported on EXTEND for up to 4 weeks. Experimental groups were distinguished by cannulation strategy: carotid artery outflow and jugular vein inflow (CA/JV; n = 4), carotid artery outflow and umbilical vein inflow (CA/UV; n = 5) and double umbilical artery outflow and umbilical vein inflow (UA/UV; n = 8). Circuit flows and pressures were measured continuously. As we transitioned from CA/JV to CA/UV to UA/UV cannulation, mean duration of circuit run and weight-adjusted circuit flows increased (P < 0.001) and the frequency of flow interruptions declined (P < 0.05). Umbilical vessels generally accommodated larger-bore cannulas, and cannula calibre was directly correlated with circuit pressures and indirectly correlated with flow:pressure ratio (a measure of post-membrane resistance). We conclude that UA/UV cannulation in fetal lambs on EXTEND optimizes circuit flow dynamics and flow stability and also supports circuit flows that closely approximate normal placental flow.

Impact of Tumor Deposits on Oncologic Outcomes in Stage III Colon Cancer.

BACKGROUND: The prognosis of tumor deposits in stage III colon adenocarcinoma is poorly described. OBJECTIVE: The purpose of this study was to determine the impact of tumor deposits on oncologic outcomes in patients with stage III colon cancer. DESIGN: This was a multicenter retrospective cohort study. SETTINGS: The 2010 to 2014 National Cancer Database was queried for patients with resected stage III colon adenocarcinoma on final pathology. PATIENTS: Patients were divided into 3 groups: lymph nodes+tumor deposits-, lymph nodes+tumor deposits+, and lymph nodes-tumor deposits+. MAIN OUTCOME MEASURES: The main outcome was 5-year overall survival. RESULTS: Of 74,577 patients, there were 55,800 patients with lymph nodes+tumor deposits-, 13,740 patients with lymph nodes+tumor deposits+, and 5037 patients with lymph nodes-tumor deposits+. The groups had similar patient and facility characteristics, but patients with lymph nodes+tumor deposits+ had more advanced tumor characteristics. Patients with lymph nodes-tumor deposits+ were less likely to receive adjuvant systemic therapy (52% vs 74% lymph nodes+tumor deposits- and 75% lymph nodes+tumor deposits+, p < 0.001) and had a longer delay to initiation of adjuvant treatment (>8 weeks; 43% vs 33% lymph nodes+tumor deposits- and 33% lymph nodes+tumor deposits+, p < 0.001). Patients with lymph nodes+tumor deposits+ had the lowest 5-year overall survival (46.0% vs 63.4% lymph nodes+tumor deposits- vs 61.9% lymph nodes-tumor deposits+, p < 0.001). On multivariate analysis, patients with lymph nodes-tumor deposits+ had similar 5-year overall survival compared with patients with lymph nodes+tumor deposits- with ≤3 positive lymph nodes (HR, 0.93; 95% CI, 0.87-1.01). Patients with lymph nodes+tumor deposits+ had worse prognosis regardless of the number of involved lymph nodes (≤3 +lymph nodes: HR, 1.37; 95% CI, 1.28-1.47 and ≥4 +lymph nodes: HR, 1.30; 95% CI, 1.22-1.38). Of those not receiving adjuvant treatment, patients with lymph nodes-tumor deposits+ were younger and had more adverse tumor features than lymph node+ disease. Lymph nodes-tumor deposits+ was independently associated with less delivery of adjuvant systemic therapy (OR, 0.81; 95% CI, 0.80-0.82). LIMITATIONS: This study was limited by its retrospective analysis of a prospective database. CONCLUSIONS: The prognosis of patients with N1c disease is similar to nodal involvement without tumor deposits, yet these patients were less likely to receive adjuvant systemic therapy. Improvement in the delivery of appropriate care in these patients may increase survival and should be a target of future quality initiatives. See Video Abstract at http://links.lww.com/DCR/A666.

Resolving complex chromosome structures during meiosis: versatile deployment of Smc5/6.

The Smc5/6 complex, along with cohesin and condensin, is a member of the structural maintenance of chromosome (SMC) family, large ring-like protein complexes that are essential for chromatin structure and function. Thanks to numerous studies of the mitotic cell cycle, Smc5/6 has been implicated to have roles in homologous recombination, restart of stalled replication forks, maintenance of ribosomal DNA (rDNA) and heterochromatin, telomerase-independent telomere elongation, and regulation of chromosome topology. The nature of these functions implies that the Smc5/6 complex also contributes to the profound chromatin changes, including meiotic recombination, that characterize meiosis. Only recently, studies in diverse model organisms have focused on the potential meiotic roles of the Smc5/6 complex. Indeed, Smc5/6 appears to be essential for meiotic recombination. However, due to both the complexity of the process of meiosis and the versatility of the Smc5/6 complex, many additional meiotic functions have been described. In this review, we provide a clear overview of the multiple functions found so far for the Smc5/6 complex in meiosis. Additionally, we compare these meiotic functions with the known mitotic functions in an attempt to find a common denominator and thereby create clarity in the field of Smc5/6 research.

Meiosis-specific cohesin component, Stag3 is essential for maintaining centromere chromatid cohesion, and required for DNA repair and synapsis between homologous chromosomes.

Cohesins are important for chromosome structure and chromosome segregation during mitosis and meiosis. Cohesins are composed of two structural maintenance of chromosomes (SMC1-SMC3) proteins that form a V-shaped heterodimer structure, which is bridged by a α-kleisin protein and a stromal antigen (STAG) protein. Previous studies in mouse have shown that there is one SMC1 protein (SMC1ß), two α-kleisins (RAD21L and REC8) and one STAG protein (STAG3) that are meiosis-specific. During meiosis, homologous chromosomes must recombine with one another in the context of a tripartite structure known as the synaptonemal complex (SC). From interaction studies, it has been shown that there are at least four meiosis-specific forms of cohesin, which together with the mitotic cohesin complex, are lateral components of the SC. STAG3 is the only meiosis-specific subunit that is represented within all four meiosis-specific cohesin complexes. In Stag3 mutant germ cells, the protein level of other meiosis-specific cohesin subunits (SMC1ß, RAD21L and REC8) is reduced, and their localization to chromosome axes is disrupted. In contrast, the mitotic cohesin complex remains intact and localizes robustly to the meiotic chromosome axes. The instability of meiosis-specific cohesins observed in Stag3 mutants results in aberrant DNA repair processes, and disruption of synapsis between homologous chromosomes. Furthermore, mutation of Stag3 results in perturbation of pericentromeric heterochromatin clustering, and disruption of centromere cohesion between sister chromatids during meiotic prophase. These defects result in early prophase I arrest and apoptosis in both male and female germ cells. The meiotic defects observed in Stag3 mutants are more severe when compared to single mutants for Smc1ß, Rec8 and Rad21l, however they are not as severe as the Rec8, Rad21l double mutants. Taken together, our study demonstrates that STAG3 is required for the stability of all meiosis-specific cohesin complexes. Furthermore, our data suggests that STAG3 is required for structural changes of chromosomes that mediate chromosome pairing and synapsis, DNA repair and progression of meiosis.

Laparoscopic right hemicolectomy: short- and long-term outcomes of intracorporeal versus extracorporeal anastomosis.

BACKGROUND: The use of laparoscopy for right hemicolectomy has gained popularity allowing the option of a totally laparoscopic intracorporeal anastomosis (IA) for intestinal reconstruction. This technique may alleviate some of the technical limitations that a surgeon faces with a laparoscopic-assisted extracorporeal anastomosis (EA). METHODS: A retrospective chart review of 195 consecutive patients who underwent laparoscopic right hemicolectomy by four colorectal surgeons at three institutions from March 2005 to June 2014 was performed. Multivariate regression analysis was used to compare postoperative and oncologic outcomes. RESULTS: A total of 195 patients underwent laparoscopic right hemicolectomy over the study period, with 86 (44 %) patients receiving IA and 109 (56 %) patients receiving an EA. The most common indication for surgery in both groups was cancer: 56 (65 %) of IA cases and 57 (52 %) of EA cases. IA had a significantly higher rate of minor complications but no difference in serious complications compared to EA. Conversion to open resection was higher in EA. Using multivariate analysis to compare IA versus EA, there was no significant difference in length of stay, return of bowel function, risk of anastomotic leak, risk of intraabdominal abscess or risk of wound complications. Amongst cancer resections, there was no significant difference in the median number of lymph nodes harvested (18 LNs in IA group vs. 19 LNs in EA group, P > 0.05). There was also no significant difference in overall survival and disease-free survival at 5.7 years between the two groups. CONCLUSIONS: IA in laparoscopic right hemicolectomy is associated with similar postoperative and oncologic outcomes compared to EA. IA may possess advantages in terms of conversion and flexibility of specimen extraction, but this is counterbalanced by a higher incidence of minor complications. These findings suggest that IA represents a valid technique in the arsenal of the experienced colorectal surgeon without compromising outcomes.