Improved Nerve Visualization in Head and Neck Surgery Using Mueller Polarimetric Imaging: Preclinical Feasibility Study in a Swine Model.

BACKGROUND AND OBJECTIVES: Meticulous dissection and identification of nerves during head and neck surgery are crucial for preventing nerve damage. At present, nerve identification relies heavily on the surgeon's knowledge of anatomy, optionally combined with intraoperative neuromonitoring. Recently, optical techniques such as Mueller polarimetric imaging (MPI) have shown potential to improve nerve identification. STUDY DESIGN/MATERIALS AND METHODS: With institutional approval, seven 25-35 kg Yorkshire pigs underwent cervical incision in the central neck. Intraoperative images were obtained using our in-house MPI system. Birefringence maps from the MPI system were processed to quantify the values between 0 and 255 from different tissue types; an active contour model was applied to further improve nerve visualization on the corresponding color images. RESULTS: Among the seven pigs, the vagus nerves and recurrent laryngeal nerves were successfully differentiated with a mean intensity of 130.954 ± 20.611, which was significantly different (P < 0.05) from those of arteries (78.512 ± 27.78) and other surrounding tissues (82.583 ± 35.547). There were no imaging-related complications during the procedure. © 2021 Wiley Periodicals LLC. CONCLUSIONS: MPI is a potentially complementary intraoperative tool for nerve identification in adjacent tissues.

Autologous intestinal reconstruction: a single institution study of the serial transverse enteroplasty (STEP) and the longitudinal intestinal lengthening and tailoring (LILT).

PURPOSE: To review the effectiveness of the longitudinal intestinal lengthening and tailoring (LILT) and serial transverse enteroplasty (STEP) operations in a cohort of patients with short bowel syndrome (SBS). METHODS: We conducted a retrospective analysis of children with SBS treated at our institution from 2004 until 2014. Children aged 0 days to 18 years with SBS who underwent autologous intestinal reconstruction were included in the study. RESULTS: Twenty-two SBS patients underwent 31 different lengthening procedures (LP). Seventeen patients underwent their primary lengthening procedures at our institution: 9 (53%) patients underwent a LILT, 7 (41%) underwent a STEP and 1 (6%) had a simultaneous LILT and STEP procedure. 12/22 patients had a second STEP, two had a third STEP and one patient had an intestinal transplantation after the LP. Median intestinal length at the time of surgery was 25 cm (range 12-90 cm). There was no difference in gain of intestinal length after LILT vs. STEP (p = 0.74). Length of stay and initiation of feeds were similar. Serum albumin increased after autologous bowel lengthening (p < 0.001). 50% were weaned off parenteral nutrition (PN) (5/9 of the LILT, 1/7 of the STEP, 1/1 of the combined LILT/STEP). There were no surgical complications or deaths. CONCLUSION: In patients with SBS, LILT and STEP procedures are effective for autologous intestinal reconstruction and enable intestinal rehabilitation.

PD-L1 checkpoint inhibition and anti-CTLA-4 whole tumor cell vaccination counter adaptive immune resistance: A mouse neuroblastoma model that mimics human disease.

BACKGROUND: Adaptive immune resistance induces an immunosuppressive tumor environment that enables immune evasion. This phenomenon results in tumor escape with progression and metastasis. Programmed cell death-ligand 1 (PD-L1) expressed on tumors is thought to inhibit tumor-infiltrating lymphocytes (TILs) through programmed cell death 1 (PD1), enabling adaptive immune resistance. This study investigates the role of PD-L1 in both mouse and human neuroblastoma immunity. The consequence of PD-L1 inhibition is characterized in the context of an established whole tumor cell vaccine. METHODS AND FINDINGS: A mouse model of neuroblastoma was investigated using an Id2 knockdown whole cell vaccine in combination with checkpoint inhibition. We show that immunogenic mouse neuroblastoma acquires adaptive immune resistance by up-regulating PD-L1 expression, whereas PD-L1 is of lesser consequence in nonimmunogenic neuroblastoma tumors. Combining PD-L1 checkpoint inhibition with whole tumor cell/anti-CTLA-4 vaccination enhanced tumor cell killing, cured mice with established tumors, and induced long-term immune memory (6 months). From an evaluation of patient neuroblastoma tumors, we found that the inflammatory environment of the mouse neuroblastoma mimicked human disease in which PD-L1 expression was associated directly with TILs and lower-risk tumors. High-risk patient tumors were lacking both TILs and PD-L1 expression. Although a correlation in immunity seems to exist between the mouse model and human findings, the mouse tumor model is induced and not spontaneously occurring, and furthermore, the number of both mouse and human correlates is limited. CONCLUSIONS: This study demonstrates the role PD-L1 plays in neuroblastoma's resistance to immunity and defines the nonredundant effect of combination checkpoint inhibition with vaccine therapy in a mouse model. High-risk, nonimmunogenic human tumors display both diminished PD-L1 expression and adaptive immune resistance. Paradoxically, high-risk tumors may be more responsive to effective vaccine therapy because of their apparent lack of adaptive immune resistance.

Changes in Autonomic Tone in Premature Infants Developing Necrotizing Enterocolitis.

BACKGROUND: Necrotizing enterocolitis (NEC) is a complication of prematurity with a high mortality rate. Currently, there are no reliable biomarkers capable of identifying infants at risk for developing NEC. We sought to determine the autonomic nervous system antecedents of NEC in premature infants, using heart rate variability (HRV). MATERIALS AND METHODS: HRV was quantified by retrieving archived electrocardiogram (EKG) data from 30 premature infants from 4 days prior, through 4 days after, the clinical NEC diagnosis. HRV metrics were compared with those on the diagnosis day using the receiver operating characteristic (ROC) analysis. RESULTS: HRV metrics showed a depression of autonomic tone that preceded the clinical NEC diagnosis by 2 days, and which recovered to baseline by 2 days after diagnosis (area under the curve [AUC] < 0.7). The pattern of HRV change was significantly associated with the clinical severity of NEC (stage II vs. stage III). CONCLUSION: Our studies suggest that readily accessible metrics of autonomic depression might expedite the diagnosis of NEC and its severity in a clinically meaningful manner. Clearly, these studies need to be extended prospectively to determine the diagnostic utility of this approach.

Prussian blue nanoparticle-based photothermal therapy combined with checkpoint inhibition for photothermal immunotherapy of neuroblastoma.

We describe "photothermal immunotherapy," which combines Prussian blue nanoparticle (PBNP)-based photothermal therapy (PTT) with anti-CTLA-4 checkpoint inhibition for treating neuroblastoma, a common, hard-to-treat pediatric cancer. PBNPs exhibit pH-dependent stability, which makes them suitable for intratumorally-administered PTT. PBNP-based PTT is able to lower tumor burden and prime an immune response, specifically an increased infiltration of lymphocytes and T cells to the tumor area, which is complemented by the antitumor effects of anti-CTLA-4 immunotherapy, providing a more durable treatment against neuroblastoma in an animal model. We observe 55.5% survival in photothermal immunotherapy-treated mice at 100days compared to 12.5%, 0%, 0%, and 0% survival in mice receiving: anti-CTLA-4 alone, PBNPs alone, PTT alone, and no treatment, respectively. Additionally, long-term surviving, photothermal immunotherapy-treated mice exhibit protection against neuroblastoma rechallenge, suggesting the development of immunity against these tumors. Our findings suggest the potential of photothermal immunotherapy in improving treatments for neuroblastoma.

VBP15, a novel dissociative steroid compound, reduces NFκB-induced expression of inflammatory cytokines in vitro and symptoms of murine trinitrobenzene sulfonic acid-induced colitis.

OBJECTIVE AND DESIGN: The goal of this study was to assess the capacity of VBP15, a dissociative steroidal compound, to reduce pro-inflammatory cytokine expression in vitro, to reduce symptoms of colitis in the trinitrobenzene sulfonic acid-induced murine model, and to assess the effect of VBP15 on growth stunting in juvenile mice. MATERIALS: In vitro studies were performed in primary human intestinal epithelial cells. Colitis was induced in mice by administering trinitrobenzene sulfonic acid. Growth stunting studies were performed in wild type outbred mice. TREATMENT: Cells were treated with VBP15 or prednisolone (10 µM) for 24 h. Mice were subjected to 3 days of VBP15 (30 mg/kg) or prednisolone (30 mg/kg) in the colitis study. In the growth stunting study, mice were subjected to VBP15 (10, 30, 45 mg/kg) or prednisolone (10 mg/kg) for 5 weeks. METHODS: Cytokines were measured by PCR and via Luminex. Colitis symptoms were evaluated by assessing weight loss, intestinal blood, and stool consistency. Growth stunting was assessed using an electronic caliper. RESULTS: VBP15 significantly reduced the in vitro production of CCL5 (p < 0.001) IL-6 (p < 0.001), IL-8 (p < 0.05) and reduced colitis symptoms (p < 0.05). VBP15 caused less growth stunting than prednisolone (p < 0.001) in juvenile mice. CONCLUSION: VBP15 may reduce symptoms of IBD, while decreasing or avoiding detrimental side effects.

Sprayable tissue adhesive with biodegradation tuned for prevention of postoperative abdominal adhesions.

Adhesions are dense, fibrous bridges that adjoin tissue surfaces due to uncontrolled inflammation following postoperative mesothelial injury. A widely used adhesion barrier material in Seprafilm often fails to prevent transverse scar tissue deposition because of its poor mechanical properties, rapid degradation profile, and difficulty in precise application. Solution blow spinning (SBS), a polymer fiber deposition technique, allows for the placement of in situ tissue-conforming and tissue-adherent scaffolds with exceptional mechanical properties. While biodegradable polymers such as poly(lactic-co-glycolic acid) (PLGA) have desirable strength, they exhibit bulk biodegradation rates and inflammatory profiles that limit their use as adhesion barriers and result in poor tissue adhesion. Here, viscoelastic poly(lactide-co-caprolactone) (PLCL) is used for its pertinent biodegradation mechanism. Because it degrades via surface erosion, spray deposited PLCL fibers can dissolve new connections formed by inflamed tissue, allowing them to function as an effective, durable, and easy-to-apply adhesion barrier. Degradation kinetics are tuned to match adhesion formation through the design of PLCL blends comprised of highly adhesive "low"-molecular weight (LMW) constituents in a mechanically robust "high"-molecular weight (HMW) matrix. In vitro studies demonstrate that blending LMW PLCL (30% w/v) with HMW PLCL (70% w/v) yields an anti-fibrotic yet tissue-adhesive polymer sealant with a 14-day erosion rate countering adhesion formation. PLCL blends additionally exhibit improved wet tissue adhesion strength (~10 kPa) over a 14-day period versus previously explored biodegradable polymer compositions, such as PLGA. In a mouse cecal ligation model, select PLCL blends significantly reduce abdominal adhesions severity versus no treatment and Seprafilm-treated controls.

Controlled Release of a Therapeutic Peptide in Sprayable Surgical Sealant for Prevention of Postoperative Abdominal Adhesions.

Formation of asymmetric, rigid scar tissue known as surgical adhesions is caused by traumatic disruption of mesothelial-lined surfaces in surgery. A widely adopted prophylactic barrier material (Seprafilm) for the treatment of intra-abdominal adhesions is applied operatively as a pre-dried hydrogel sheet but has reduced translational efficacy due its brittle mechanical properties. Topically administered peritoneal dialysate (Icodextrin) and anti-inflammatory drugs have failed to prevent adhesions due to an uncontrolled release profile. Hence, inclusion of a targeted therapeutic into a solid barrier host matrix with improved mechanical properties could provide dual utility in adhesion prevention and as a surgical sealant. Spray deposition of poly(lactide-co-caprolactone) (PLCL) polymer fibers through solution blow spinning has yielded a tissue-adherent barrier material with previously reported adhesion prevention efficacy due to a surface erosion mechanism that inhibits deposition of inflamed tissue. However, such an approach uniquely presents an avenue for controlled therapeutic release through mechanisms of diffusion and degradation. Such a rate is kinetically tuned via facile blending of "high" molecular weight (HMW) and "low" molecular weight (LMW) PLCL with slow and fast biodegradation rates, respectively. Here, we explore viscoelastic blends of HMW PLCL (70% w/v) and LMW PLCL (30% w/v) as a host matrix for anti-inflammatory drug delivery. In this work, COG133, an apolipoprotein E (ApoE) mimetic peptide with potent anti-inflammatory properties was selected and tested. In vitro studies with PLCL blends presented low (∼30%) and high (∼80%) percent release profiles over a 14-day period based on the nominal molecular weight of the HMW PLCL component. Two independent mouse models of cecal ligation and cecal anastomosis significantly reduced adhesion severity versus Seprafilm, COG133 liquid suspension, and no treatment control. The synergy of physical and chemical methods in a barrier material with proven preclinical studies highlights the value of COG133-loaded PLCL fiber mats in effectively dampening the formation of severe abdominal adhesions.

Unsupervised and quantitative intestinal ischemia detection using conditional adversarial network in multimodal optical imaging.

Purpose: Intraoperative evaluation of bowel perfusion is currently dependent upon subjective assessment. Thus, quantitative and objective methods of bowel viability in intestinal anastomosis are scarce. To address this clinical need, a conditional adversarial network is used to analyze the data from laser speckle contrast imaging (LSCI) paired with a visible-light camera to identify abnormal tissue perfusion regions. Approach: Our vision platform was based on a dual-modality bench-top imaging system with red-green-blue (RGB) and dye-free LSCI channels. Swine model studies were conducted to collect data on bowel mesenteric vascular structures with normal/abnormal microvascular perfusion to construct the control or experimental group. Subsequently, a deep-learning model based on a conditional generative adversarial network (cGAN) was utilized to perform dual-modality image alignment and learn the distribution of normal datasets for training. Thereafter, abnormal datasets were fed into the predictive model for testing. Ischemic bowel regions could be detected by monitoring the erroneous reconstruction from the latent space. The main advantage is that it is unsupervised and does not require subjective manual annotations. Compared with the conventional qualitative LSCI technique, it provides well-defined segmentation results for different levels of ischemia. Results: We demonstrated that our model could accurately segment the ischemic intestine images, with a Dice coefficient and accuracy of 90.77% and 93.06%, respectively, in 2560 RGB/LSCI image pairs. The ground truth was labeled by multiple and independent estimations, combining the surgeons' annotations with fastest gradient descent in suspicious areas of vascular images. The total processing time was 0.05 s for an image size of 256 × 256 . Conclusions: The proposed cGAN can provide pixel-wise and dye-free quantitative analysis of intestinal perfusion, which is an ideal supplement to the traditional LSCI technique. It has potential to help surgeons increase the accuracy of intraoperative diagnosis and improve clinical outcomes of mesenteric ischemia and other gastrointestinal surgeries.

Evaluation of healing outcomes combining a novel polymer formulation with autologous skin cell suspension to treat deep partial and full thickness wounds in a porcine model: a pilot study.

Autologous skin cell suspensions (ASCS) can treat burns of varying depths with the advantage of reduced donor site wound burden. The current standard primary dressing for ASCS is a nonabsorbant, non-adherent, perforated film (control) which has limited conformability over heterogeneous wound beds and allows for run-off of the ASCS. To address these concerns, a novel spray-on polymer formulation was tested as a potential primary dressing in porcine deep partial thickness (DPT) and full thickness (FT) wounds. It was hypothesized that the polymer would perform as well as control dressing when evaluating wound healing and scarring. DPT or FT wounds were treated with either a spray-on poly(lactic-co-glycolic acid) (PLGA) and poly(lactide-co-caprolactone) (PLCL) formulation or control ASCS dressings. Throughout the experimental time course (to day 50), we found no significant differences between polymer and control wounds in % re-epithelialization, graft-loss, epidermal or dermal thickness, or % dermal cellularity in either model. Pigmentation, erythema, elasticity, and trans-epidermal water loss (TEWL), were not significantly altered between the treatment groups, but differences between healing wounds/scars and un-injured skin were observed. No cytotoxic effect was observed in ASCS incubated with the PLGA and PLCL polymers. These data suggest that the novel spray-on polymer is a viable option as a primary dressing, with improved ease of application and conformation to irregular wounds. Polymer formulation and application technique should be a subject of future research.

Tracheal Agenesis: Vertical Division of the Native Esophagus - A Novel Surgical Approach and Review of the Literature.

INTRODUCTION: Tracheal agenesis (TA) is rare and usually fatal. Few survivors with concomitant tracheoesophageal fistulae (TEF) who underwent ligation of the distal esophagus with creation of a spit-fistula and neo-trachea from the proximal esophagus exist. We report a novel surgical technique whereby the esophagus is divided longitudinally to preserve a functional alimentation tract and a parallel neo-trachea. We review the literature of reported cases, including survivors beyond 12 months. METHODS: Case report and literature review. RESULTS: A female infant with prenatal polyhydramnios was born at 35 weeks gestation with immediate respiratory distress and absent cry. Oxygenation was maintained with a laryngeal mask airway. Despite a normal appearing larynx, she could not be intubated and emergent neck exploration disclosed no cervical trachea. The patient was placed on extra corporeal membranous oxygenation (ECMO), and later diagnosed with TA, Floyd Type I. Parental desire for reconstruction but refusal of a spit-fistula necessitated a novel procedure. The esophagus was divided longitudinally via a microstapler to preserve the original alimentary tract and create a parallel neo-trachea originating from the TEF and terminating as a cervical stoma. The healing process was complicated but the baby was ultimately discharged to home where she developed normally neurologically until succumbing one night to accidental decannulation at 16 months of age. CONCLUSION: We describe a novel surgical approach to manage TA. This includes avoiding creation of a spit fistula and preserving the native esophagus. We then survey the literature, reporting the survivorship duration and operative management of 174 reported cases of TA.

Mediated Electrochemical Probing: A Systems-Level Tool for Redox Biology.

Biology uses well-known redox mechanisms for energy harvesting (e.g., respiration), biosynthesis, and immune defense (e.g., oxidative burst), and now we know biology uses redox for systems-level communication. Currently, we have limited abilities to "eavesdrop" on this redox modality, which can be contrasted with our abilities to observe and actuate biology through its more familiar ionic electrical modality. In this Perspective, we argue that the coupling of electrochemistry with diffusible mediators (electron shuttles) provides a unique opportunity to access the redox communication modality through its electrical features. We highlight previous studies showing that mediated electrochemical probing (MEP) can "communicate" with biology to acquire information and even to actuate specific biological responses (i.e., targeted gene expression). We suggest that MEP may reveal an extent of redox-based communication that has remained underappreciated in nature and that MEP could provide new technological approaches for redox biology, bioelectronics, clinical care, and environmental sciences.

Biodegradable, Tissue Adhesive Polyester Blends for Safe, Complete Wound Healing.

Pressure-sensitive adhesives typically used for bandages are nonbiodegradable, inhibiting healing, and may cause an allergic reaction. Here, we investigated the effect of biodegradable copolymers with promising thermomechanical properties on wound healing for their eventual use as biodegradable, biocompatible adhesives. Blends of low molecular weight (LMW) and high molecular weight (HMW) poly(lactide-co-caprolactone) (PLCL) are investigated as tissue adhesives in comparison to a clinical control. Wounds treated with PLCL blend adhesives heal completely with similar vascularization, scarring, and inflammation indicators, yet require fewer dressing changes due to integration of the PLCL adhesive into the wound. A blend of LMW and HMW PLCL produces an adhesive material with significantly higher adhesive strength than either neat polymer. Wound adhesion is comparable to a polyurethane bandage, utilizing conventional nonbiodegradable adhesives designed for extremely strong adhesion.

Effective adoptive therapy of tap-deficient lymphoma using diverse high avidity alloreactive T cells.

High avidity for antigen and diversity of T cell receptor (TCR) repertoire are essential for effective immunity against cancer. We have previously created a transgenic mouse strain with increased TCR avidity in a diverse T cell population. In this report, we show that strong alloreactive responses of transgenic T cells against targets with low MHC class I expression can be used for effective adoptive transfer of tumor immunity in vivo. Alloreactive transgenic T cells could be an effective therapeutic approach counteracting tumor evasion of the immune system.

Pressure-Sensitive Tissue Adhesion and Biodegradation of Viscoelastic Polymer Blends.

Viscoelastic blends of biodegradable polyesters with low and high molecular weight distributions have remarkably strong adhesion (significantly greater than 1 N/cm2) to soft, wet tissue. Those that transition from viscous flow to elastic, solidlike behavior at approximately 1 Hz demonstrate pressure-sensitivity yet also have sufficient elasticity for durable bonding to soft, wet tissue. The pressure-sensitive tissue adhesive (PSTA) blends produce increasingly stronger pull-apart adhesion in response to compressive pressure application, from 10 to 300 s. By incorporating a stiffer high molecular weight component, the PSTA exhibits dramatically improved burst pressure (greater than 100 kPa) when used as a tissue sealant. The PSTA's biodegradation mechanism can be switched from erosion (occurring primarily over the first 10 days) to bulk chemical degradation (and minimal erosion) depending on the chemistry of the high molecular weight component. Interestingly, fibrosis toward the PSTA is reduced when fast-occurring erosion is the dominant biodegradation mechanism.

Sprayable and biodegradable, intrinsically adhesive wound dressing with antimicrobial properties.

Conventional wound dressings are difficult to apply to large total body surface area (TBSA) wounds, as they typically are prefabricated, require a layer of adhesive coating for fixation, and need frequent replacement for entrapped exudate. Large TBSA wounds as well as orthopedic trauma and low-resource surgery also have a high risk of infection. In this report, a sprayable and intrinsically adhesive wound dressing loaded with antimicrobial silver is investigated that provides personalized fabrication with minimal patient contact. The dressing is composed of adhesive and biodegradable poly(lactic-co-glycolic acid) and poly(ethylene glycol) (PLGA/PEG) blend fibers with or without silver salt (AgNO3). in vitro studies demonstrate that the PLGA/PEG/Ag dressing has antimicrobial properties and low cytotoxicity, with antimicrobial silver controllably released over 7-14 days. In a porcine partial-thickness wound model, the wounds treated with both antimicrobial and nonantimicrobial PLGA/PEG dressings heal at rates similar to those of the clinical, thin film polyurethane wound dressing, with similar scarring. However, PLGA/PEG adds a number of features beneficial for wound healing: greater exudate absorption, integration into the wound, a 25% reduction in dressing changes, and tissue regeneration with greater vascularization. There is also modest improvement in epidermis thickness compared to the control wound dressing.

High-Intensity Focused Ultrasound (HIFU) Triggers Immune Sensitization of Refractory Murine Neuroblastoma to Checkpoint Inhibitor Therapy.

PURPOSE: Immunotherapy promises unprecedented benefits to patients with cancer. However, the majority of cancer types, including high-risk neuroblastoma, remain immunologically unresponsive. High-intensity focused ultrasound (HIFU) is a noninvasive technique that can mechanically fractionate tumors, transforming immunologically "cold" tumors into responsive "hot" tumors. EXPERIMENTAL DESIGN: We treated <2% of tumor volume in previously unresponsive, large, refractory murine neuroblastoma tumors with mechanical HIFU and assessed systemic immune response using flow cytometry, ELISA, and gene sequencing. In addition, we combined this treatment with αCTLA-4 and αPD-L1 to study its effect on the immune response and long-term survival. RESULTS: Combining HIFU with αCTLA-4 and αPD-L1 significantly enhances antitumor response, improving survival from 0% to 62.5%. HIFU alone causes upregulation of splenic and lymph node NK cells and circulating IL2, IFNγ, and DAMPs, whereas immune regulators like CD4+Foxp3+, IL10, and VEGF-A are significantly reduced. HIFU combined with checkpoint inhibitors induced significant increases in intratumoral CD4+, CD8α+, and CD8α+CD11c+ cells, CD11c+ in regional lymph nodes, and decrease in circulating IL10 compared with untreated group. We also report significant abscopal effect following unilateral treatment of mice with large, established bilateral tumors using HIFU and checkpoint inhibitors compared with tumors treated with HIFU or checkpoint inhibitors alone (61.1% survival, P < 0.0001). This combination treatment significantly also induces CD4+CD44+hiCD62L+low and CD8α+CD44+hiCD62L+low population and is adoptively transferable, imparting immunity, slowing subsequent de novo tumor engraftment. CONCLUSIONS: Mechanical fractionation of tumors using HIFU can effectively induce immune sensitization in a previously unresponsive murine neuroblastoma model and promises a novel yet efficacious immunoadjuvant modality to overcome therapeutic resistance.

Immune stimulatory antigen loaded particles combined with depletion of regulatory T-cells induce potent tumor specific immunity in a mouse model of melanoma.

Anti-tumor vaccines capable of activating both CD4 and CD8 T cells are preferred for long lasting T cell responses. Induction of a tumor-specific T-cell response can be induced by tumor vaccines that target innate immunity. The ensuing T-cell response depends on efficient antigen presentation from phagocytosed cargo in the antigen presenting cell and is augmented by the presence of Toll-like receptor (TLR) ligands within the cargo. Biodegradable polymers are useful for vaccine delivery in that they are phagocytosed by antigen presenting cells (APCs) and could potentially be loaded with both the antigen and immune stimulatory TLR agents. This study was undertaken to evaluate the effect of poly lactic-co-glycolic acid (PLGA) polymer particles loaded with antigenic tumor lysate and immune stimulatory CpG oligonucleotides on induction of tumor specific immunity in a mouse model of melanoma. We found that after delivery, these immune stimulatory antigen loaded particles (ISAPs) efficiently activated APCs and were incorporated into lysosomal compartments of macrophages and dendritic cells. ISAP vaccination resulted in remarkable T cell proliferation, but only modestly suppressed tumor growth of established melanoma. Due to this discordant effect on tumor immunity we evaluated the role of regulatory T cells (Treg) and found that ISAP vaccination or tumor growth alone induced prolific expansion of tumor specific Treg. When the Treg compartment was suppressed with anti-CD25 antibody, ISAP vaccination induced complete antigen-specific immunity in a prophylactic model. ISAP vaccination is a novel tumor vaccine strategy that is designed to co-load the antigen with a TLR agonist enabling efficient Ag presentation. Targeting of T-reg expansion during vaccination may be necessary for inducing effective tumor-specific immunity.

Congenital paraesophageal hernia: Contemporary results and outcomes of laparoscopic approach to repair in symptomatic infants and children.

BACKGROUND: Congenital paraesophageal hernia (CPEH) is a rare diaphragmatic anomaly for which repair has primarily been described by laparotomy, although, more recent case series describe laparoscopic repair. In reports with over five patients, the predominant approach has been with laparotomy. The purpose of our study was to review our recent institutional experience and results with exclusively laparoscopic repair of CPEH in infants and children. METHODS: An IRB approved retrospective review of all patients with CPEH who underwent laparoscopic treatment at a tertiary children's hospital from 2010 to 2017 was performed. We included only those patients from our own institution with primary CPEH, or CPEH with prior repair (s) at other centers, with recurrence presenting for operation. Data including demographics, diagnostic studies, operative details, complications, outcomes, and follow up were analyzed. Age at diagnosis was 1 day to 25 years of age (mean 2.5 years). RESULTS: A total 28 patients underwent 30 operations to treat CPEH. All operations were completed laparoscopically with no conversions to open. There were 6 Type II, 16 Type III, and 6 Type IV CPEH patients. Seventeen patients were less than one year of age (61%). Weight at time of repair was 10.3 kg (1.2-44 kg). Twelve patients were less than 5 kg (43%), eight patients (28.5%) were less than 10 kg, and 8 were more than 10 kg (28.5%). Operative time averaged 125 min (range 61-247 min). Three patients underwent initial CPEH repair (s) (open: 2 and laparoscopic: 1) at other institutions before laparoscopic revision was performed at our hospital (11%). Crural repair was performed in all patients, fundoplication in 26 (93%) and concomitant gastrostomy was performed in 14 patients (50%). Complications included two patients with recurrent hiatal hernias, which were redone laparoscopically (2/28 or 7% recurrence) and 1 capnothorax requiring pigtail drainage postoperatively. There were no deaths, no requirement for esophageal dilations, or esophageal lengthening. One patient required laparoscopic gastrostomy six weeks post initial repair for failure to thrive. Follow-up ranged from 4 months to 8 years (average 36 months). CONCLUSION: Congenital paraesophageal hernia in infants and children is uncommon. Based on our experience, the laparoscopic approach to repair is feasible, even for neonates, with excellent results, acceptably low recurrence rate, and may even be considered for revisional operations. STUDY TYPE: Clinical research paper. LEVEL OF EVIDENCE: Type IV.

Improving the adhesion, flexibility, and hemostatic efficacy of a sprayable polymer blend surgical sealant by incorporating silica particles.

Commercially available surgical sealants for internal use either lack sufficient adhesion or produce cytotoxicity. This work describes a surgical sealant based on a polymer blend of poly(lactic-co-glycolic acid) (PLGA) and poly(ethylene glycol) (PEG) that increases wet tissue adherence by incorporation of nano-to-microscale silica particles, without significantly affecting cell viability, biodegradation rate, or local inflammation. In functional studies, PLGA/PEG/silica composite sealants produce intestinal burst pressures that are comparable to cyanoacrylate glue (160 mmHg), ∼2 times greater than the non-composite sealant (59 mmHg), and ∼3 times greater than fibrin glue (49 mmHg). The addition of silica to PLGA/PEG is compatible with a sprayable in situ deposition method called solution blow spinning and decreases coagulation time in vitro and in vivo. These improvements are biocompatible and cause minimal additional inflammation, demonstrating the potential of a simple composite design to increase adhesion to wet tissue through physical, noncovalent mechanisms and enable use in procedures requiring simultaneous occlusion and hemostasis. STATEMENT OF SIGNIFICANCE: Incorporating silica particles increases the tissue adhesion of a polymer blend surgical sealant. The particles enable interfacial physical bonding with tissue and enhance the flexibility of the bulk of the sealant, without significantly affecting cytotoxicity, inflammation, or biodegradation. These studies also demonstrate how silica particles decrease blood coagulation time. This surgical sealant improves upon conventional devices because it can be easily deposited with accuracy directly onto the surgical site as a solid polymer fiber mat. The deposition method, solution blow spinning, allows for high loading in the composite fibers, which are sprayed from a polymer blend solution containing suspended silica particles. These findings could easily be translated to other implantable or wearable devices due to the versatility of silica particles.