Neuronal Spiking Responses to Direct Electrical Microstimulation in the Human Cortex.

Microstimulation can modulate the activity of individual neurons to affect behavior, but the effects of stimulation on neuronal spiking are complex and remain poorly understood. This is especially challenging in the human brain where the response properties of individual neurons are sparse and heterogeneous. Here we use microelectrode arrays in the human anterior temporal lobe in 6 participants (3 female) to examine the spiking responses of individual neurons to microstimulation delivered through multiple distinct stimulation sites. We demonstrate that individual neurons can be driven with excitation or inhibition using different stimulation sites, which suggests an approach for providing direct control of spiking activity at the single-neuron level. Spiking responses are inhibitory in neurons that are close to the site of stimulation, while excitatory responses are more spatially distributed. Together, our data demonstrate that spiking responses of individual neurons can be reliably identified and manipulated in the human cortex.SIGNIFICANCE STATEMENT One of the major limitations in our ability to interface directly with the human brain is that the effects of stimulation on the activity of individual neurons remain poorly understood. This study examines the spiking responses of neurons in the human temporal cortex in response to pulses of microstimulation. This study finds that individual neurons can either be excited or inhibited depending on the site of stimulation. These data suggest an approach for modulating the spiking activity of individual neurons in the human brain.

LONG-TERM OUTCOMES OF INTRAVITREAL BEVACIZUMAB THERAPY FOR SUBRETINAL NEOVASCULARIZATION SECONDARY TO IDIOPATHIC MACULAR TELANGIECTASIA TYPE 2.

PURPOSE: To assess the long-term visual acuity results for intravitreal bevacizumab therapy in the treatment of subretinal neovascular membrane (SRNVM) secondary to idiopathic macular telangiectasia (Mactel) Type 2. METHODS: This retrospective review of a consecutive, interventional case series includes patients with SRNVM secondary to Mactel Type 2 who were seen at Cincinnati Eye Institute from February 2006 to December 2014. Best-corrected visual acuity, fluorescein angiography, and optical coherence tomography measurements were performed. Exclusion criteria were the following: Mactel Type 2 patients without SRNVM, Mactel Type 1 patients, patients who had SRNVM or macular edema related to other maculopathies, and patients who had pars plana vitrectomy or laser treatment to the macula during the course of care or before their first visit. RESULTS: Twenty-five eyes of 20 patients with SRNVM secondary to Mactel Type 2 were included in the study. The mean baseline best-corrected visual acuity was 20/91 (median: 20/69) and the mean final best-corrected visual acuity was 20/62 (median: 20/60) at the last visit (P < 0.0001). The mean number of injections was 8.4 ± 11.1 (range: 2-53, median: 4). The mean pretreatment central macular thickness of 254 µm improved to 205 µm at the final visit (P = 0.011). No complications related to intravitreal bevacizumab injection were noted during the mean follow-up time of 40.8 ± 33.7 months (range: 4-108 months, median: 24 months). CONCLUSION: Intravitreal bevacizumab therapy is an effective long-term treatment modality for SRNVM secondary to Mactel Type 2 based on improvement in best-corrected visual acuity and associated reduction in central macular thickness.

A North American, single-center experience implanting fenestrated atrial devices and atrial flow regulators into a heterogeneous group of pediatric pulmonary hypertension patients.

Introduction: The clinical deterioration commonly experienced by pediatric patients with pulmonary arterial hypertension (PAH) has motivated a shift in the treatment of pulmonary hypertension (PH) through innovations in surgical salvage interventions. The Occlutech fenestrated atrial septal defect (FASD) Occluder and the atrial flow regulator (AFR), which provides a protective, atrial-level shunt during hypertensive crises, have found an important role in treating pediatric patients with PAH. Other groups of pediatric patients with PH may also benefit from a similar protective physiology. The primary aim of this work is to present a single center's experience with AFR and FASD devices for managing a heterogeneous group of pediatric PH patients. A secondary goal is to identify hemodynamic changes and complications following device implantation. Materials and Methods: We performed a retrospective review of all pediatric PH patients who, after being found suitable, either successfully or unsuccessfully received an FASD or AFR device between January 2015 and December 2021 at the Stollery Children's Hospital in Edmonton, Canada. Results: Fourteen patients (eight female) with a median age of 4.6 (range 0.3-17.9) years and a median body mass index of 15.1 (Q1 = 13.8, Q3 = 16.8) kg/m2 underwent device implantation: five received FASDs, eight received AFRs, and one was ultimately unable to receive an implant due to thrombosed iliac vessels and required surgical intervention. Of the fourteen patients, seven were in group 1 (PAH), one was in group 3 (lung disease), and six were in group 5 (primarily pulmonary hypertension vascular disease) under the World Symposium PH classification. All patients were on mono-, dual-, or triple-drug PH therapy. Device stabilization was not possible for two patients, who then required a repeat catheterization. Of the group 1 patients, three AFR and three FASD implants were successful, while one FASD implant was unsuccessful due to thrombosed vessels. At a six-month clinical assessment, all group 1 patients had patent devices and improved WHO FCs. Conclusion: This work presents a single center's experience with AFR and FASD implants in a heterogeneous group of fourteen pediatric patients with severe PH. This treatment strategy is novel in the pediatric population and so this work provides momentum for future studies of interventional cardiac catheterization procedures for pediatric patients with PH. Further collaborations are required to develop criteria to identify ideal pediatric candidates and optimally time interventions in order to maximize the benefits of this treatment.

Multicenter review of a tadalafil suspension formulation for infants and children with pulmonary hypertension: A North American experience.

Introduction: Phosphodiesterase type 5 (PDE5) inhibitors, with sildenafil the earliest among them, are widely used in the management of pediatric pulmonary arterial hypertension (PAH). Tadalafil is a PDE5 inhibitor with a long half life (16 h), stable pharmacokinetics and pharmacodynamics, and minimal adverse effects. However, the utility of tadalafil suspensions in this setting has not been widely explored due to a lack of clinical experience. We present a multicenter experience that details the safety and tolerability of a tadalafil suspension, either alone or in combination with another vasodilator, for the management of pediatric pulmonary hypertension (PH). Methods and materials: This is a retrospective chart review of infants and children at Children's Wisconsin and the Stollery Children's Hospital enrolled in pediatric PH programs between December 2013 and April 2022 managed with a tadalafil suspension. Patients aged six years of age and under who were treated with a tadalafil suspension were included. Demographics, clinical information, echocardiographic and hemodynamic measurements, and laboratory data were collected before and six months after tadalafil initiation. Results: Over the study period, 154 children with a median age of 1.0 (range 0.0-6.9) years were treated with tadalafil therapy. Of these, 39 (25.3%) were in group 1 (PAH), 79 (51.3%) were in group 3 (lung disease), and 33 (21.4%) were in group 5 (pulmonary hypertensive vascular disease). The median initial dose of tadalafil was 1.0 mg/kg once daily. Eleven (7.1%) patients in the cohort were established on tadalafil therapy de novo. The suspension formulation was necessary for 103 (66.9%) patients due to an inability to take enteral tablets and for 49 (31.8%) due to a need for feeding via gastric or jejunal tubes. We observed a statistically significant increase in tricuspid annular plane systolic excursion as well as significant decreases in right-ventricular systolic pressure and NT-proBNP. Tadalafil therapy was well tolerated over the six-month period: at six months, no adverse effects were reported aside from gastrointestinal disturbances by 2 (1.3%) patients. Conclusion: Tadalafil, a long-acting PDE5 inhibitor, when administered in a suspension formulation, has a safe and tolerable adverse effect profile. Following six months of therapy, our cohort showed improvements in clinical parameters, echocardiographic measurements, and laboratory results. Patient compliance was good and adverse effects were rare, minor, and manageable with nonpharmacological means.

A Canadian, retrospective, multicenter experience with selexipag for a heterogeneous group of pediatric pulmonary hypertension patients.

Introduction: Selexipag, an oral nonprostanoid prostaglandin receptor agonist, has led to reduced morbidity and mortality in adults with pulmonary arterial hypertension (PAH). While the adult literature has been extrapolated to suggest selexipag as an oral treatment for severe pediatric pulmonary hypertension (PH), longitudinal, multicenter data on the benefits of selexipag in this population are lacking. The purpose of this study is to present a longitudinal, multicentre experience with selexipag in a relatively large cohort of pediatric PH patients and add to the existing selexipag literature. Materials and methods: We performed a retrospective, multicenter review describing the clinical outcomes of pediatric PH patients receiving selexipag in addition to standard oral pulmonary vasodilator therapy across three Canadian centers between January 2005 and June 2021. Results: Twenty-four pediatric patients (fifteen female) with a mean age of 9.7 (range 2.0-15.5) years were included. Of this cohort, eighteen (75.0%) were in group 1, one (4.2%) was in group 2, four (16.7%) were in group 3, and one (4.2%) was in group 4. Twenty-two (91.7%) patients were on dual PH therapy after six months. Dosing was targeted to achieve 20-30 mcg/kg/dose orally every twelve hours. Median dose after twelve months was 30 mcg/kg/dose. Twelve months following selexipag initiation, median decreases of 0.2 cm in tricuspid annular plane systolic excursion, 3.5 mmHg in right-ventricular systolic pressure, and 6.1 mmHg in mean pulmonary arterial pressure were observed; none of these changes were statistically significant. Three patients died, one clinically deteriorated and required admission to a pediatric intensive care unit, ten had gastrointestinal symptoms, and three had flushing. Conclusion: Selexipag appears to be a safe and effective adjunctive therapy for pediatric PH patients and has a tolerable adverse effect profile aside from gastrointestinal disturbances. Additional prospective studies of changes in hemodynamics and functional classification over a longer period and with a larger sample are needed. Future research should aim to identify subgroups that stand to benefit from the addition of selexipag as well as optimal timing and dosing for the pediatric population.

Correlation of ventricular septal defect height and outcomes after complete atrioventricular septal defect repair.

OBJECTIVES: There are limited data available on the height of the ventricular component of the septal deficiency (VSD) in patients undergoing complete atrioventricular septal defect (CAVSD) repair. VSD height may influence optimal choice of repair strategy with potential consequences for long-term outcomes. We aimed to measure VSD height using 2-dimensional echocardiography and review its association with postoperative outcomes. METHODS: We retrospectively reviewed the preoperative echocardiograms of 45 consecutive patients who underwent CAVSD repair between May 2010 and December 2015 at a single centre. VSD height and left ventricular length on the four-chamber view were measured. Demographic details and early and late outcomes including reoperation and long-term survival were studied. RESULTS: Twenty patients underwent modified single-patch repair and 25 patients underwent double-patch repair of CAVSD. VSD height in the modified single-patch group ranged from 4.2 to 11.7 mm and in the double-patch group ranged from 5.1 to 14.9 mm. Nine patients had a deep 'scoop' with a VSD height of >10 mm, (7 double patch, 2 modified single patch). VSD height did not correlate with a specific Rastelli classification. There was no significant difference in the VSD height (P = 0.51) or the VSD height-to-left ventricular length ratio (P = 0.43) between the 2 repair groups. There was no 30-day mortality. Eight patients required reoperation; however, VSD height was not a significant predictor of reoperation (hazard ratio 0.95, 95% confidence interval 0.69-1.33; P = 0.08). CONCLUSIONS: There was no correlation between VSD height and risk of reoperation after CAVSD repair. A deep ventricular scoop is uncommon in CAVSD patients.

Small bowel intussusception and Enterobius vermicularis infestation in a 20-year-old woman.

A 20-year-old woman presented with abdominal pain and MRI findings of intussusception of the distal small bowel with no identifiable lead point and no visualisation of the appendix. A diagnostic laparoscopy succeeded in manually reducing the intussusception but was unable to find any candidate lead point. Intraoperatively, hyperperistalsis was observed throughout the small bowel which seemed prone to transient intussusception. Incidental appendectomy revealed an uninflamed appendix with Enterobius vermicularis (pinworm) infestation, the most common parasite present in appendectomy specimens worldwide. Although intussusception in young adults is an uncommon occurrence, the unique nature of this case is amplified by the concurrent finding of E. vermicularis infection of the appendix in an adolescent in western Canada, a phenomenon normally observed in paediatric populations with higher incidence in tropical areas. Although the mechanism of intussusception in this patient remains unclear, it is hypothesised that E. vermicularis colonisation acted as an irritant stimulating intestinal hypercontractility with resulting intussusception. Successful medical eradication of the pinworm in this individual may prevent future recurrence.

Evaluation of personalized right ventricle to pulmonary artery conduits using in silico design and computational analysis of flow.

Objectives: Right ventricle to pulmonary artery (RV-PA) conduits are required for the surgical management of pulmonary atresia with ventricular septal defect and truncus arteriosus. Bioengineered RV-PA connections may address some of the shortcomings of homografts and xenografts, such as lack of growth potential and structural deterioration and may be manufactured to accommodate patient-specific anatomy. The aim of this study was to develop a methodology for in silico patient-specific design and analysis of RV-PA conduits. Methods: Cross-sectional imaging was obtained from patients with truncus arteriosus (n = 5) and pulmonary atresia with ventricular septal defect (n = 5) who underwent complete repair with a RV-PA conduit. Three-dimensional models of the heart were constructed by segmentation of the right ventricle, existing conduit, branch pulmonary arteries, and surrounding structures. A customized conduit design for each patient was proposed. Computational fluid dynamics analysis was performed and outputs, including wall shear stress and energy loss, were used to compare the performance of the existing conduits and the customized geometries. Results: In this study, a methodology for patient-specific analysis of RV-PA conduit in silico was developed. The results of simulations for 10 patients showed between 23% and 56% decrease in the average wall shear stress and between 24% and 87% reduction in average power requirements in customized designs compared with the stenosed conduits, translating into better hemodynamic performance. Conclusions: Creation of an optimal conduit for an individual patient can be achieved using surgeon-guided design and computational fluid dynamics analysis. Manufacture of personalized RV-PA conduits may obviate the need for surgical customization to accommodate existing materials and provide superior long-term outcomes.

Alkaline phosphatase-positive colony formation is a sensitive, specific, and quantitative indicator of undifferentiated human embryonic stem cells.

Human embryonic stem cells (hESCs) can be maintained in vitro as immortal pluripotent cells but remain responsive to many differentiation-inducing signals. Investigation of the initial critical events involved in differentiation induction would be greatly facilitated if a specific, robust, and quantitative assay for pluripotent hESCs with self-renewal potential were available. Here we describe the results of a series of experiments to determine whether the formation of adherent alkaline phosphatase-positive (AP(+)) colonies under conditions optimized for propagating undifferentiated hESCs would meet this need. The findings can be summarized as follows. (a) Most colonies obtained under these conditions consist of >or=30 AP(+) cells that coexpress OCT4, NANOG, SSEA3, SSEA4, TRA-1-60, and TRA-1-81. (b) Most such colonies are derived from SSEA3(+) cells. (c) Primary colonies contain cells that produce secondary colonies of the same composition, including cells that initiate multilineage differentiation in embryoid bodies (EBs). (d) Colony formation is independent of plating density or the colony-forming cell (CFC) content of the test population over a wide range of cell concentrations. (e) CFC frequencies decrease when differentiation is induced by exposure either to retinoic acid or to conditions that stimulate EB formation. Interestingly, this loss of AP(+) clonogenic potential also occurs more rapidly than the loss of SSEA3 or OCT4 expression. The CFC assay thus provides a simple, reliable, broadly applicable, and highly specific functional assay for quantifying undifferentiated hESCs with self-renewal potential. Its use under standardized assay conditions should enhance future elucidation of the mechanisms that regulate hESC propagation and their early differentiation.

Cytomegalovirus duodenitis associated with life-threatening duodenal hemorrhage in an immunocompetent patient: A case report.

INTRODUCTION: Cytomegalovirus (CMV) is known to be opportunistic in immunocompromised patients. However, there have been emerging cases of severe CMV infections found in immunocompetent patients. Gastrointestinal (GI) CMV disease is the most common manifestation affecting immunocompetent patients, with duodenal involvement being exceedingly rare. Presented is a case of an immunocompetent patient with life-threatening bleeding caused by CMV duodenitis, requiring surgical intervention. PRESENTATION OF CASE: A 60-year-old male with history of disseminated Methicillin-sensitive Staphylococcus aureus (MSSA) bacteremia and aortic valve infective endocarditis, presented with life-threatening upper GI hemorrhage. Endoscopy revealed ulcerations, with associated generalized mucosal bleeding in the duodenum. After repeated endoscopic therapies and failed interventional-radiology arterial embolization, the patient required a duodenectomy and associated total pancreatectomy, to control the duodenal hemorrhage. Pathologic review of the surgical specimen demonstrated CMV duodenitis. Systemic ganciclovir was utilized postoperatively. DISCUSSION: GI CMV infections should be on the differential diagnosis of immunocompetent patients presenting with uncontrollable GI bleeding, especially in critically ill patients due to transiently suppressed immunity. Endoscopic and histopathological examinations are often required for diagnosis. Ganciclovir is first-line treatment. Surgical intervention may be considered if there is recurrent bleeding and CMV duodenitis is suspected because of high potential for bleeding-associated mortality. CONCLUSION: Presented is a rare case of life-threatening GI hemorrhage caused by CMV duodenitis in an immunocompetent patient. The patient failed endoscopic and interventional-radiology treatment options, and ultimately stabilized after surgical intervention.

Multicenter assessment of neoadjuvant chemotherapy for muscle-invasive bladder cancer.

BACKGROUND: The efficacy of neoadjuvant chemotherapy (NAC) for muscle-invasive bladder cancer (BCa) was established primarily with methotrexate, vinblastine, doxorubicin, and cisplatin (MVAC), with complete response rates (pT0) as high as 38%. However, because of the comparable efficacy with better tolerability of gemcitabine and cisplatin (GC) in patients with metastatic disease, GC has become the most commonly used regimen in the neoadjuvant setting. OBJECTIVE: We aimed to assess real-world pathologic response rates to NAC with different regimens in a large, multicenter cohort. DESIGN, SETTING, AND PARTICIPANTS: Data were collected retrospectively at 19 centers on patients with clinical cT2-4aN0M0 urothelial carcinoma of the bladder who received at least three cycles of NAC, followed by radical cystectomy (RC), between 2000 and 2013. INTERVENTION: NAC and RC. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: The primary outcome was pathologic stage at cystectomy. Univariable and multivariable analyses were used to determine factors predictive of pT0N0 and ≤pT1N0 stages. RESULTS AND LIMITATIONS: Data were collected on 935 patients who met inclusion criteria. GC was used in the majority of the patients (n=602; 64.4%), followed by MVAC (n=183; 19.6%) and other regimens (n=144; 15.4%). The rates of pT0N0 and ≤pT1N0 pathologic response were 22.7% and 40.8%, respectively. The rate of pT0N0 disease for patients receiving GC was 23.9%, compared with 24.5% for MVAC (p=0.2). There was no difference between MVAC and GC in pT0N0 on multivariable analysis (odds ratio: 0.89 [95% confidence interval, 0.61-1.34]; p=0.6). CONCLUSIONS: Response rates to NAC were lower than those reported in prospective randomized trials, and we did not discern a difference between MVAC and GC. Without any evidence from randomized prospective trials, the best NAC regimen for invasive BCa remains to be determined. PATIENT SUMMARY: There was no apparent difference in the response rates to the two most common presurgical chemotherapy regimens for patients with bladder cancer.

Cystic intratesticular lesions in pediatric patients.

BACKGROUND/PURPOSE: Intratesticular cysts are a rare clinical entity in the pediatric population. Recently, testes sparing surgery has been recommended. We share our experience with the management of pediatric testicular cysts. METHODS: A retrospective review of all pediatric patients referred for intratesticular cysts was conducted at a single pediatric institution from 2002 to 2010. Charts were evaluated for patient demographics, diagnosis, and management. RESULTS: Seven patients were identified and included in this series. After partial orchiectomy, the final diagnosis in three patients was epidermoid cyst. Three further patients were diagnosed as mature cystic teratoma, with two of these demonstrating adjacent intra-tubular germ cell neoplasia (ITGCN). One cyst in the series underwent spontaneous resolution after eight months. CONCLUSION: All of the cystic lesions in our case series were benign with one undergoing complete resolution. The remainder became smaller and developed a solid component prompting surgery. The pre-pubertal findings of ITGCN in two patients raise a dilemma regarding the optimal long-term management for these patients. Initial conservative observation is an option for the majority of pre-pubertal cystic testicular lesions until such time that testis sparing surgery is deemed technically feasible. Testes sparing surgery should be advocated in those patients undergoing surgical management.