Osh proteins regulate phosphoinositide metabolism at ER-plasma membrane contact sites.

Sac1 phosphoinositide (PI) phosphatases are essential regulators of PI-signaling networks. Yeast Sac1, an integral endoplasmic reticulum (ER) membrane protein, controls PI4P levels at the ER, Golgi, and plasma membrane (PM). Whether Sac1 can act in trans and turn over PI4P at the Golgi and PM from the ER remains a paradox. We find that Sac1-mediated PI4P metabolism requires the oxysterol-binding homology (Osh) proteins. The PH domain-containing family member, Osh3, localizes to PM/ER membrane contact sites dependent upon PM PI4P levels. We reconstitute Osh protein-stimulated Sac1 PI phosphatase activity in vitro. We also show that the ER membrane VAP proteins, Scs2/Scs22, control PM PI4P levels and Sac1 activity in vitro. We propose that Osh3 functions at ER/PM contact sites as both a sensor of PM PI4P and an activator of the ER Sac1 phosphatase. Our findings further suggest that the conserved Osh proteins control PI metabolism at additional membrane contact sites.

Surgical outcomes in large vestibular schwannomas: should cerebellopontine edema be considered in the grading systems?

PURPOSE: Large (> 3 cm) vestibular schwannomas pose complexity in surgical management because of narrow working corridors and proximity to the cranial nerves, brainstem, and inner ear structures. With current vestibular schwannoma classifications limited in information regarding cerebellopontine edema, our retrospective series examined this radiographic feature relative to clinical outcomes and its possible role in preoperative scoring. METHODS: Of 230 patients who underwent surgical resection of vestibular schwannoma (2014-2020), we identified 107 patients with Koos grades 3 or 4 tumors for radiographic assessment of edema in the middle cerebellar peduncle (MCP), brainstem, or both. Radiographic images were graded and patients grouped into Koos grades 3 or 4 or our proposed grade 5 with edema. Tumor volumes, radiographic features, clinical presentations, and clinical outcomes were evaluated. RESULTS: The 107 patients included 22 patients with grade 3 tumors, 39 with grade 4, and 46 with grade 5. No statistical differences were noted among groups for demographic data or complication rates. Unlike grades 3 and 4 patients, grade 5 patients presented with worse hearing (p < 0.001), larger tumors (p < 0.001), lower rates of gross total resection (GTR), longer hospital stays, and higher rates of balance dysfunction. CONCLUSION: With edema detected in 43% of this cohort, special considerations are warranted for grade 5 vestibular schwannomas given the preoperative findings of worse hearing, lower GTR rates, longer hospital stays, and 96% who pursued postoperative balance therapy. We propose that grade 5 with edema offers a more nuanced interpretation of a radiographic feature that holds relevance to treatment selection and patient outcomes.

Structure of lipoprotein lipase in complex with GPIHBP1.

Lipoprotein lipase (LPL) plays a central role in triglyceride (TG) metabolism. By catalyzing the hydrolysis of TGs present in TG-rich lipoproteins (TRLs), LPL facilitates TG utilization and regulates circulating TG and TRL concentrations. Until very recently, structural information for LPL was limited to homology models, presumably due to the propensity of LPL to unfold and aggregate. By coexpressing LPL with a soluble variant of its accessory protein glycosylphosphatidylinositol-anchored high-density lipoprotein binding protein 1 (GPIHBP1) and with its chaperone protein lipase maturation factor 1 (LMF1), we obtained a stable and homogenous LPL/GPIHBP1 complex that was suitable for structure determination. We report here X-ray crystal structures of human LPL in complex with human GPIHBP1 at 2.5-3.0 Å resolution, including a structure with a novel inhibitor bound to LPL. Binding of the inhibitor resulted in ordering of the LPL lid and lipid-binding regions and thus enabled determination of the first crystal structure of LPL that includes these important regions of the protein. It was assumed for many years that LPL was only active as a homodimer. The structures and additional biochemical data reported here are consistent with a new report that LPL, in complex with GPIHBP1, can be active as a monomeric 1:1 complex. The crystal structures illuminate the structural basis for LPL-mediated TRL lipolysis as well as LPL stabilization and transport by GPIHBP1.

A Comparison of the Short-term Outcomes of Three Flap Reconstruction Techniques Used After Beyond Total Mesorectal Excision Surgery for Anorectal Cancer.

BACKGROUND: Surgery for advanced or recurrent pelvic malignancy can result in perineal defects that cannot be closed by wound edge approximation. Myocutaneous flaps can fill the defect and accelerate healing. No reconstruction has been proven to be superior to the others. OBJECTIVE: This study aimed to compare 3 flap procedures after beyond total mesorectal excision surgery. DESIGN: This is a retrospective analysis of a prospective database, according to the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement. SETTINGS: This study was performed at a tertiary hospital. PATIENTS: Consecutive series of patients who required flap reconstruction after beyond total mesorectal excision surgery between 2007 and 2016 were included. MAIN OUTCOME MEASURES: Short-term outcomes after oblique rectus abdominis flap vs vertical rectus abdominis flap vs inferior gluteal artery perforator flap reconstruction were evaluated. RESULTS: Included are 65 (59%) oblique rectus abdominis flap, 30 (27.3%) vertical rectus abdominis flap, and 15 (13.7%) inferior gluteal artery perforator flap outcomes. Sacrectomy was performed in 12 (18.5%), 10 (33.3%), and 8 (53.3%) patients (p = 0.016). Preoperative radiotherapy was used in 60 (92.3%), 26 (86.7%), and 11 (73.3%) patients (p = 0.11). Flap infection and dehiscence occurred in 7 (10.8%), 1 (3.3%), and 4 (26.7%) patients. There was an increased risk of flap complication with inferior gluteal artery perforator flap vs vertical rectus abdominis flap (p = 0.036). Inferior gluteal artery perforator flap (OR, 6.26; p = 0.02) and obesity (OR, 4.96; p = 0.02) were associated with flap complications. Only complications of the oblique rectus abdominis flap decreased significantly over time (p = 0.03). The length of stay and complete (R0) resection rate were not different between the groups. LIMITATIONS: This study was limited because of its retrospective nature and because it was conducted at a single center. CONCLUSIONS: The techniques appear comparable. The approaches should be considered complementary, and the choice should be individualized. See Video Abstract at http://links.lww.com/DCR/B141. COMPARACIÓN DE RESULTADOS A CORTO PLAZO DE TRES TÉCNICAS DE RECONSTRUCCIÓN CON COLGAJO UTILIZADAS DESPUÉS DE LA CIRUGÍA DE ESCISIÓN MESORRECTAL TOTAL EXTENDIDA PARA EL CÁNCER ANORRECTAL: La cirugía para malignidad pélvica avanzada o recurrente puede provocar defectos perineales, que no pueden cerrarse por aproximación de los bordes de la herida. Los colgajos miocutáneos pueden llenar el defecto y acelerar la curación. Ninguna reconstrucción ha demostrado ser superior a las demás.Comparar tres procedimientos de colgajo después de una cirugía de escisión mesorrectal total extendida.Análisis retrospectivo de una base de datos prospectiva, de acuerdo con la Declaración de Fortalecimiento de los informes de estudios observacionales en epidemiología.Hospital de tercer nivel.Series consecutivas de pacientes que requirieron reconstrucción con colgajo después de una cirugía de escisión mesorrectal total extendida entre 2007 y 2016.Resultados a corto plazo después del colgajo oblicuo recto abdominal versus colgajo vertical recto abdominal versus reconstrucción del colgajo perforador de la arteria glútea inferior.Se incluyen 65 (59%) colgajo oblicuo recto abdominal oblicuo, 30 (27.3%) colgajo vertical recto abdominal y 15 (13.7%) colgajo perforador de la arteria glútea inferior. Sacrectomía se realizó en 12 (18.5%), 10 (33.3%) y 8 (53.3%) pacientes respectivamente (p = 0.016). La radioterapia preoperatoria se utilizó en 60 (92.3%), 26 (86.7%) y 11 (73.3%) (p = 0,11). La infección del colgajo y la dehiscencia ocurrieron en 7 (10.8%), 1 (3.3%) y 4 (26.7%). Hubo un mayor riesgo de complicación con el colgajo perforador de la arteria glútea inferior en comparación al colgajo vertical del recto abdominal (p = 0.036). El colgajo perforador de la arteria glútea inferior (OR 6.26, p = 0.02) y la obesidad (OR 4.96, p = 0.02) se asociaron con complicaciones del colgajo. Solo las complicaciones del colgajo oblicuo recto abdominal disminuyeron significativamente con el tiempo (p = 0.03). La duración de la estancia hospitalaria y la tasa de resección completa (R0) no fue diferente entre los grupos.Estudio retrospectivo en centro único.Las técnicas parecen comparables. Los enfoques deben considerarse complementarios y la elección individualizada. Consulte Video Resumen en http://links.lww.com/DCR/B141.

Burst suppression uncovers rapid widespread alterations in network excitability caused by an acute seizure focus.

Burst suppression is an electroencephalogram pattern of globally symmetric alternating high amplitude activity and isoelectricity that can be induced by general anaesthetics. There is scattered evidence that burst suppression may become spatially non-uniform in the setting of underlying pathology. Here, we induced burst suppression with isoflurane in rodents and then created a neocortical acute seizure focus with injection of 4-aminopyridine (4-AP) in somatosensory cortex. Burst suppression events were recorded before and after creation of the focus using bihemispheric wide-field calcium imaging and multielectrode arrays. We find that the seizure focus elicits a rapid alteration in triggering, initiation, and propagation of burst suppression events. Compared with the non-seizing brain, bursts are triggered from the thalamus, initiate in regions uniquely outside the epileptic focus, elicit marked increases of multiunit activity and propagate towards the seizure focus. These findings support the rapid, widespread impact of focal epilepsy on the extended brain network.

In Vivo Femtosecond Laser Subsurface Cortical Microtransections Attenuate Acute Rat Focal Seizures.

Recent evidence shows that seizures propagate primarily through supragranular cortical layers. To selectively modify these circuits, we developed a new technique using tightly focused, femtosecond infrared laser pulses to make as small as ~100 µm-wide subsurface cortical incisions surrounding an epileptic focus. We use this "laser scalpel" to produce subsurface cortical incisions selectively to supragranular layers surrounding an epileptic focus in an acute rodent seizure model. Compared with sham animals, these microtransections completely blocked seizure initiation and propagation in 1/3 of all animals. In the remaining animals, seizure frequency was reduced by 2/3 and seizure propagation reduced by 1/3. In those seizures that still propagated, it was delayed and reduced in amplitude. When the recording electrode was inside the partially isolated cube and the seizure focus was on the outside, the results were even more striking. In spite of these microtransections, somatosensory responses to tail stimulation were maintained but with reduced amplitude. Our data show that just a single enclosing wall of laser cuts limited to supragranular layers led to a significant reduction in seizure initiation and propagation with preserved cortical function. Modification of this concept may be a useful treatment for human epilepsy.

Role of inhibitory control in modulating focal seizure spread.

Focal seizure propagation is classically thought to be spatially contiguous. However, distribution of seizures through a large-scale epileptic network has been theorized. Here, we used a multielectrode array, wide field calcium imaging, and two-photon calcium imaging to study focal seizure propagation pathways in an acute rodent neocortical 4-aminopyridine model. Although ictal neuronal bursts did not propagate beyond a 2-3-mm region, they were associated with hemisphere-wide field potential fluctuations and parvalbumin-positive interneuron activity outside the seizure focus. While bicuculline surface application enhanced contiguous seizure propagation, focal bicuculline microinjection at sites distant to the 4-aminopyridine focus resulted in epileptic network formation with maximal activity at the two foci. Our study suggests that both classical and epileptic network propagation can arise from localized inhibition defects, and that the network appearance can arise in the context of normal brain structure without requirement for pathological connectivity changes between sites.

Structure based design of nicotinamide phosphoribosyltransferase (NAMPT) inhibitors from a phenotypic screen.

Nicotinamide phosphoribosyltransferase is a key metabolic enzyme that is a potential target for oncology. Utilizing publicly available crystal structures of NAMPT and in silico docking of our internal compound library, a NAMPT inhibitor, 1, obtained from a phenotypic screening effort was replaced with a more synthetically tractable scaffold. This compound then provided an excellent foundation for further optimization using crystallography driven structure based drug design. From this approach, two key motifs were identified, the (S,S) cyclopropyl carboxamide and the (S)-1-N-phenylethylamide that endowed compounds with excellent cell based potency. As exemplified by compound 27e such compounds could be useful tools to explore NAMPT biology in vivo.

Glial Calcium Waves are Triggered by Seizure Activity and Not Essential for Initiating Ictal Onset or Neurovascular Coupling.

It has been postulated that glia play a critical role in modifying neuronal activity, mediating neurovascular coupling, and in seizure initiation. We investigated the role of glia in ictogenesis and neurovascular coupling through wide-field multicell and 2-photon single cell imaging of calcium and intrinsic signal imaging of cerebral blood volume in an in vivo rat model of focal neocortical seizures. Ictal events triggered a slowly propagating glial calcium wave that was markedly delayed after both neuronal and hemodynamic onset. Glial calcium waves exhibited a stereotypical spread that terminated prior to seizure offset and propagated to an area ~60% greater than the propagation area of neural and vascular signals. Complete blockage of glial activity with fluoroacetate resulted in no change in either neuronal or hemodynamic activity. These ictal glial waves were blocked by carbenoxolone, a gap junction blocker. Our in vivo data reveal that ictal events trigger a slowly propagating, stereotypical glial calcium wave, mediated by gap junctions, that is spatially and temporally independent of neuronal and hemodynamic activities. We introduce a novel ictally triggered propagating glial calcium wave calling into question the criticality of glial calcium wave in both ictal onset and neurovascular coupling.

A Systematic Review to Assess Resection Margin Status After Abdominoperineal Excision and Pelvic Exenteration for Rectal Cancer.

OBJECTIVE: The aim of this study was to assess resection margin status and its impact on survival after abdominoperineal excision and pelvic exenteration for primary or recurrent rectal cancer. SUMMARY OF BACKGROUND DATA: Resection margin is important to guide therapy and to evaluate patient prognosis. METHODS: A meta-analysis was performed to assess the impact of resection margin status on survival, and a regression analysis to analyze positive resection margin rates reported in the literature. RESULTS: The analysis included 111 studies reporting on 19,607 participants after abdominoperineal excision, and 30 studies reporting on 1326 participants after pelvic exenteration. The positive resection margin rates for abdominoperineal excision were 14.7% and 24.0% for pelvic exenteration. The overall survival and disease-free survival rates were significantly worse for patients with positive compared with negative resection margins after abdominoperineal excision [hazard ratio (HR) 2.64, P < 0.01; HR 3.70, P < 0.01, respectively] and after pelvic exenteration (HR 2.23, P < 0.01; HR 2.93, P < 0.01, respectively). For patients undergoing abdominoperineal excision with positive resection margins, the reported tumor sites were 57% anterior, 15% posterior, 10% left or right lateral, 8% circumferential, 10% unspecified. A significant decrease in positive resection margin rates was identified over time for abdominoperineal excision. Although positive resection margin rates did not significantly change with the size of the study, some small size studies reported higher than expected positive resection margin rates. CONCLUSIONS: Resection margin status influences survival and a multidisciplinary approach in experienced centers may result in reduced positive resection margins. For advanced anterior rectal cancer, posterior pelvic exenteration instead of abdominoperineal excision may improve resection margins.

Integrated Patient Coordination System (IntPaCS): a bespoke tool for surgical patient management.

BACKGROUND: Efficient handover of patient information is fundamental for patient care and service efficiency. An audit exploring surgeons' views on written handover within a Trust's surgical specialties concluded that clear deficiencies existed. Such concerns have been echoed in the General Medical Council's guidance on safe surgical handover. AIMS: To design and implement bespoke software for surgical handover using the audit results of surgeons' perceptions of existing processes. To gain feedback from the surgical department on this new software and implement a long-term sustainability strategy. METHODS: Following an initial review, a proposal was presented for a new patient management tool. The software was designed and developed in-house to reflect the needs of our surgeons. The bespoke programme used open-source coding and was maintained on a secure server. A review of surgical handover occurred 12 and 134 weeks post-implementation of the new software. RESULTS: Integrated Patient Coordination System (IntPaCS) was successfully developed and delivered. The system is a centralised platform that enables the visualisation, handover and audit/research of surgical inpatient information in any part of the hospital. Feedback found that clinicians found it less stressful to create a post-take handover (60% vs 36%) than using a Word document. IntPaCS was found to be quicker to use too (15 min (SD 4) vs 24 min (SD 7.5)). Finally, the new system was considered safer with less reported missing/incorrect patient data (48% vs 9%). CONCLUSIONS: This study has shown that careful use of emerging technology and innovation over time has the potential to improve all aspects of clinical governance.

Idiopathic Intracranial Hypertension.

Idiopathic intracranial hypertension is defined by headaches and a decline in visual acuity due to increased intracranial pressure. Treatment options historically included weight loss, acetazolamide, and/or cerebrospinal fluid diversion surgery. Recent understanding of the contributions of dural venous sinus hypertension and stenosis has led to venous sinus stenting as a treatment option.

Utility of Routine Surveillance Head Computed Tomography After Receiving Therapeutic Anticoagulation in Patients with Acute Traumatic Intracranial Hemorrhage.

INTRODUCTION: Patients with traumatic intracranial hemorrhage (tICH) are at increased risk of venous thromboembolism and may require anticoagulation. We evaluated the utility of surveillance computed tomography (CT) in patients with tICH who required therapeutic anticoagulation. METHODS: This single institution, retrospective study included adult patients with tICH who required anticoagulation within 4 weeks and had a surveillance head CT within 24 hours of reaching therapeutic anticoagulation levels. The primary outcome was hematoma expansion (HE) detected by the surveillance CT. Secondary outcomes included 1) changes in management in patients with HE on the surveillance head CT, 2) HE in the absence of clinical changes, and 3) mortality due to HE. We also compared mortality between patients who did and did not have a surveillance CT. RESULTS: Of 175 patients, 5 (2.9%) were found to have HE. Most (n = 4, 80%) had changes in management including anticoagulation discontinuation (n = 4), reversal (n = 1), and operative management (n = 1). Two patients developed symptoms or exam changes prior to the head CT. Of the 3 patients (1.7%) without preceding exam changes, each had only very minor HE and did not require operative management. No patient experienced mortality directly attributed to HE. There was no difference in mortality between patients who did and those who did not have a surveillance scan. CONCLUSIONS: Our findings suggest that most patients with tICH who are started on anticoagulation could be followed clinically, and providers may reserve CT imaging for patients with changes in exam/symptoms or those who have a poor clinical examination to follow.

Single-Electrode Deep Brain Stimulation of Bilateral Posterolateral Globus Pallidus Internus in Patients With Medically Resistant Lesch-Nyhan Syndrome.

Deep brain stimulation (DBS) targeting various locations within the globus pallidus internus (GPi) is emerging as a therapeutic option for patients with medically resistant Lesch-Nyhan syndrome. We report our institutional experience with single-electrode DBS in the bilateral posterolateral GPi as an effective method for reduction of both dystonia and self-injurious behavior. Two pediatric patients aged six and 14 years underwent implantation of bilateral singular DBS leads in the posterolateral GPi and were followed postoperatively through the programming process and symptomatic improvements. Caregivers reported that after DBS in the posterolateral GPi, these patients experienced decreased self-mutilation behavior and decreased dystonia.

Multiple painful plaques and the Sweet's syndrome.

We present a rare case of Sweet's syndrome. A 39-year-old woman with subjective fevers, polyarthralgia, and malaise presented with worsening painful erythematous plaques on the trunk, arms, and legs. Further examination with biopsy revealed a diagnosis of acute febrile neutrophilic dermatosis, or Sweet's syndrome. Diagnosis by skin biopsy is crucial, and onset requires prompt evaluation for serious associated disorders such as leukemias, inflammatory bowel disease, thyroid disease, sarcoidosis, and infectious etiologies. In general, symptoms and cutaneous manifestations of Sweet syndrome respond rapidly to treatment with systemic corticosteroids or potassium iodide.

Validation of the NeuMoDx™ SARS-CoV-2 assay with COPAN eNAT® and E&O Viral PCR Sample Solution collection media types in comparison with other validated SARS-CoV-2 RNA assays.

OBJECTIVES: This study aimed to confirm NeuMoDx™ SARS-CoV-2 assay (NeuMoDx assay) functionality using off-label collection media, determine assay performance versus other SARS-CoV-2 RNA assays, and assess any cross-reactivity with other respiratory viruses (human coronavirus NL63, influenza, and respiratory syncytial virus). METHODS: Nasopharyngeal swab samples in off-label collection media and external quality assessment (EQA) samples were dual-tested, first using either the RealStar® SARS-CoV-2 reverse transcriptase polymerase chain reaction assay or the QIAstat-Dx® Respiratory SARS-CoV-2 Panel and then using the NeuMoDx assay. Samples found to be positive for respiratory viruses and negative for SARS-CoV-2 were then tested using the NeuMoDx assay to assess cross-reactivity. RESULTS: Overall, 274 samples (244 patient and 30 EQA samples) were dual-tested; 154 were SARS-CoV-2 positive and 120 were negative. No false-positive or false-negative results were identified, regardless of collection medium used. The NeuMoDx assay sensitivity was 100% (95% confidence interval [CI] 97.63-100.00) and the specificity was 100% (95% CI 96.97-100.00). The assay did not exhibit any cross-reactivity with other respiratory viruses. CONCLUSION: The NeuMoDx assay demonstrated high sensitivity and specificity on a platform well-suited for fully automated SARS-CoV-2 testing.

Management of full-thickness skin grafts.

Full-thickness skin grafts are a commonly used reconstructive method following Mohs micrographic surgery. The literature varies on the most appropriate methods of suturing and securing grafts as well as best practices to dress the graft postoperatively. Our objective was to review various approaches to management of full-thickness skin grafts, including suturing the graft, securing the graft, and topical emollient use on the graft postoperatively. It was found that absorbable sutures, plain gut, provide preferable outcomes with full-thickness skin grafts. The tie-over bolster is the most-used method for securing skin grafts after placement, although several other methods have demonstrated efficacy, including the polyurethane foam, sandwich, and quilting suture methods. While various topical emollients are used in the immediate postoperative period, plain white petrolatum is the least likely to form allergic contact dermatitis.

Is your patient a candidate for Mohs micrographic surgery?

This guide for family physicians describes the advantages of Mohs surgery and which patients make good candidates for the procedure.

Length-dependent toxicity of TiO2 nanofibers: mitigation via shortening.

Length and aspect ratio represent important toxicity determinants of fibrous nanomaterials. We have previously shown that anatase TiO2 nanofibers (TiO2 NF) cause a dose-dependent decrease of cell viability as well as the loss of epithelial barrier integrity in polarized airway cell monolayers. Herein we have investigated the impact of fiber shortening, obtained by ball-milling, on the biological effects of TiO2 NF of industrial origin. Long TiO2 NF (L-TiO2 NF) were more cytotoxic than their shortened counterparts (S-TiO2 NF) toward alveolar A549 cells and bronchial 16HBE cells. Moreover, L-TiO2 NF increased the permeability of 16HBE monolayers and perturbed the distribution of tight-junction proteins, an effect also mitigated by fiber shortening. Raw264.7 macrophages efficiently internalized shortened but not long NF, which caused cell stretching and deformation. Compared with L-TiO2 NF, S-TiO2 NF triggered a more evident macrophage activation, an effect suppressed by the phagocytosis inhibitor cytochalasin B. Conversely, a significant increase of inflammatory markers was detected in either the lungs or the peritoneal cavity of mice exposed to L-TiO2 NF but not to S-TiO2 NF, suggesting that short-term macrophage activation in vitro may not be always a reliable indicator of persistent inflammation in vivo. It is concluded that fiber shortening mitigates NF detrimental effects on cell viability and epithelial barrier competence in vitro as well as inflammation development in vivo. These data suggest that fiber shortening may represent an effective safe-by-design strategy for mitigating TiO2 NF toxic effects.