Morphological features of mucous secretory organ and mucous secretion of loach Misgurnus anguillicaudatus skin for friction drag reduction.

We examined the functional morphology of loach Misgurnus anguillicaudatus skin by using synchrotron X-ray micro-computed tomography (SR-µCT) and high-contrast staining using osmium tetroxide or phosphotungstic acid (PTA), which enhances the image contrast of soft tissues. The captured high-spatial resolution images revealed that the surface ornamentations were stuck in the basement membrane of the loach scales. The ornamentations consisting of grooves (radii) and ridges (circuli) that can move freely and bend flexibly. The cross-sectional lateral microstructures of flat, concave and convex loach skins were observed from a live image of loach skin obtained through dark-field optical coherence tomography (OCT) imaging. The thickness of loach skin was changed with varying empty space between the mucous-cell layer and the scales by bending motion of loach. In addition, through direct measurement of drag reduction of loach skin, the mucous layer was found to have a strong influence on the reduction of skin friction. The present results enhance the understanding of the functional morphologies of mucous layer of loach to secrete mucus for skin friction reduction.

Aortopexy and thymectomy through lower partial sternotomy for the treatment of airway compression in a patient with right lung agenesis.

We managed a case of extrinsic airway compression by adjacent structures in a 1-month-old boy with right lung agenesis and dextro-rotated heart using anterior aortopexy and near total thymectomy.

A STAT6 Inhibitor AS1517499 Reduces Preventive Effects of Apoptotic Cell Instillation on Bleomycin-Induced Lung Fibrosis by Suppressing PPARγ.

BACKGROUND/AIMS: The signal transducer and activator of transcription 6 (STAT6) transcription factor mediates PPARγ-regulated gene expression in macrophages. However, it remains largely unknown how proximal membrane signaling events initiated by apoptotic cell recognition upregulate PPARγ expression and activate the lung homeostatic program. METHODS: The STAT6 inhibitor AS1517499 was used to determine the role of STAT6 in mediating PPARγ activity, anti-inflammatory effects, and anti-fibrotic effects induced by apoptotic cell instillation after bleomycin treatment into C57BL/6 mice. Bronchoalveolar lavage fluid, alveolar macrophages and lungs were harvested at days 2, 7, and 14 and then analyzed by real-time PCR, immunoblotting, ELISA, immunocytochemistry and immunohistochemistry assays. RESULTS: Our data demonstrate that apoptotic cell instillation after bleomycin results in prolonged enhancement of STAT6 phosphorylation in alveolar macrophages and lung. Co-administration of the STAT6 inhibitor, AS1517499, reversed the enhanced PPARγ expression and activity induced by apoptotic cell instillation after bleomycin treatment. By reducing the expression of PPARγ target genes, including CD36, macrophage mannose receptor, and arginase 1, AS1517499 inhibited efferocytosis and restored pro-inflammatory cytokine expression, neutrophil recruitment, protein levels, hydroxyproline content, and expression of fibrosis markers, including type 1 collagen α2, fibronectin, and α-smooth muscle actin. STAT6 inhibition reversed the expression profile of hepatocyte growth factor and interleukin-10. CONCLUSION: These results indicate that prolonged STAT6 activation following one-time apoptotic cell instillation facilitates continuous PPARγ activation, resulting in the resolution of bleomycin-induced lung inflammation and fibrosis.

Multidisciplinary Management of an Internal Carotid Artery Aneurysm Near the Skull Base.

Extracranial carotid artery aneurysms (ECAAs) are rare in comparison to the total number of peripheral artery aneurysms. Although there are multiple treatment modalities, no clear guidelines exist for the optimal management of ECAA. We describe a case of a 59-year-old female with an incidental finding of a 2.6 cm right internal carotid artery (ICA) aneurysm on computed tomography (CT) that was eventually excised via transcervical approach followed by end-to-end anastomosis with great saphenous vein (GSV) graft. To our knowledge, this case demonstrates a novel multidisciplinary approach to an ECAA near the skull base involving head and neck surgery (HNS), vascular surgery (VS), and neuro-interventional radiology (NIR).

Development of an in vivo murine model of perineural invasion and spread of cutaneous squamous cell carcinoma of the head and neck.

Introduction: Cutaneous squamous cell carcinoma of the head and neck (cSCCHN) can metastasize by invading nerves and spread toward the central nervous system. This metastatic process is called perineural invasion (PNI) and spread (PNS). An in vivo sciatic nerve mouse model is used for cSCCHN PNI/PNS. Here we describe a complementary whisker pad model which allows for molecular studies investigating drivers of PNI/PNS in the head and neck environment. Methods: A431 cells were injected into the whisker pads of BALB/c Foxn1nu and NSG-A2 mice. Tumor progression was monitored by bioluminescence imaging and primary tumor resection was performed. PNI was detected by H&E and IHC. Tumor growth and PNI were assessed with inducible ablation of LOXL2. Results: The rate of PNI development in mice was 10%-28.6%. Tumors exhibited PNI/PNS reminiscent of the morphology seen in the human disease. Our model's utility was demonstrated with inducible ablation of LOXL2 reducing primary tumor growth and PNI. Discussion: This model consists in a feasible way to test molecular characteristics and potential therapies, offers to close a gap in the described in vivo methods for PNI/PNS of cSCCHN and has uses in concert with the established sciatic nerve model.

Utilization of Silicone Sheet as a Protective Guide During Transoral Robotic Tongue Base Surgery.

This article presents a simple technique where a silicone sheet is used during transoral robotic surgery (TORS) to protect the upper airway structures from thermal damage during a base of tongue procedure. We review 10 cases of TORS tongue base reduction with the use of this technique, with no complications and with reduction of thermal damage to the lingual epiglottis and surrounding pharyngeal wall. Furthermore, it served as a guide during tongue base dissection to provide visual and tactile feedback to the inferior limit of resection, as well as to protect the endotracheal tube. The silicone sheet is an ideal material for use as a thermal barrier due to its widespread availability, intrinsic thermal properties, and translucency. The technique of using the silicone sheet is easy to implement and may prove useful to many transoral robotic surgeons, especially for newly trained TORS users and trainees.

Head and Neck Tumor Resection and Free Flap Reconstruction in Low-Volume Center.

OBJECTIVE: To determine the surgical outcomes of free tissue transfer surgery following head and neck tumor extirpation in a low-volume medical center. METHODS: Retrospective chart review of patients who underwent free tissue transfer surgery for head and neck cancer at Moanalua Medical Center from 2015 to 2018. MAIN OUTCOME OF MEASURE: Free flap failure rate and free flap-related complications. RESULTS: From 2015 to 2018, there were 27 free tissue transfer surgery (mean 6.75 flap surgery/year). There were 2 events of partial flap necrosis, and no cases of total flap loss. One patient required leech therapy for venous congestion. One patient required additional free flap surgery. Two patients developed orocutaneous fistula that resolved with local wound care. One patient developed malocclusion following mandible reconstruction using fibular free flap. Overall free flap success rate was 96%. CONCLUSION: This study supports the ability of small-volume centers to produce positive outcomes with few complications in head and neck cancer free flap reconstructive surgery. While the data are limited to a single surgical team in one care center, it provides additional support for the idea that there are factors beyond the surgical volume that determine outcome.

Comparison of an oropharyngeal pH probe and a standard dual pH probe for diagnosis of laryngopharyngeal reflux.

OBJECTIVES: We compared the ability of an oropharyngeal (OP) aerosol-detecting pH probe and a standard dual pH probe in measuring laryngopharyngeal reflux (LPR). METHODS: Fifteen subjects with LPR symptoms had 24-hour simultaneous placement of the OP probe and a standard dual pH probe. Acid exposure was defined as a 10% pH decrease below baseline for the OP probe or a pH of less than 4 at the upper esophageal sphincter (UES) probe of the dual pH probe. RESULTS: The mean duration of acid exposure was 650 seconds (SD, 619) or 0.75% of the total time for the OP probe and 438 seconds (SD, 511) or 0.51% of the total time for the UES probe. When we excluded meals and sleep, the mean duration of acid exposure was 271 seconds (SD, 356) or 0.31% of the total time for the OP probe and 271 seconds (SD, 359) or 0.31% of the total time for the UES probe. The correlation coefficient (R) between the two probes for measurement of the duration of acid exposure was 0.50 (p < 0.05). When we excluded meals and the supine position, the R was notably higher, at 0.95 (p < 0.0001). CONCLUSIONS: The OP probe reliably documented LPR events when meals and sleep were eliminated and was better tolerated than the standard dual probe.

Supraclavicular Artery Island Flap in Head and Neck Reconstruction: A Case Series and Literature Review.

INTRODUCTION: Supraclavicular artery island flap (SCAIF) is emerging as an efficient and reliable flap for various complex head and neck defects after tumor extirpation. OBJECTIVE: To examine a series of cases using a SCAIF for head and reconstruction at our institution. METHODS: We performed a retrospective review of 8 patients who underwent SCAIF reconstruction of various head and neck defects from 2015 to 2018 at our institution. We also reviewed the English-language literature of reports of a SCAIF used for head and neck defects. RESULTS: Eight patients underwent SCAIF reconstruction of head and neck defects. Various anatomic sites were reconstructed including the neck (n = 4), oral cavity (n = 1), and parotid/lateral skull base (n = 3). Two patients had partial flap necrosis, requiring débridement and wound care. There was no total loss of the flap or donor-site complication. CONCLUSION: SCAIF is an excellent choice for reconstructing various head and neck defects, with low complication rates and donor-site morbidity. The outcomes of our SCAIF reconstruction are comparable to previously published outcomes.

Developmental expression of Xenopus fragile X mental retardation-1 gene.

Dysregulation of Fragile X mental retardation-1 (Fmr1) gene expression results in an inherited form of mental retardation known as the Fragile X syndrome (FXS). Fmr1 is a highly conserved gene with a broad yet distinctive expression pattern during vertebrate development. Here, we examined the expression pattern of Fmr1 during Xenopus embryonic development. Zygotic expression of Fmr1 began just prior to gastrulation and gradually increased during subsequent embryonic stages. By in situ hybridization, Fmr1 transcripts were detected by early tailbud stage and showed robust expression in the central nervous system (CNS), eye and pharyngeal arches. By late tailbud stage, Fmr1 expression became stronger in the CNS and craniofacial regions including the ear vesicle and eye. In addition, the notochord expressed high levels of Fmr1 transcripts in the late tailbud stage embryos. In the tadpole brain, the olfactory bulb and cerebellum exhibited strong Fmr1 expression. The developmental expression pattern of Fmr1 is consistent with the wide range of abnormalities observed in FXS. Further, our findings indicate that Xenopus will serve as an excellent model to study the developmental basis of this disease.

Novel mouse model for simulating microsurgical tumor excision with facial nerve preservation.

OBJECTIVES/HYPOTHESIS: To determine the feasibility of using a mouse tumor model as a microsurgical training tool for otolaryngology-head and neck surgery (OHNS) trainees. STUDY DESIGN: Animal study. METHODS: We injected athymic nude mice with human cutaneous squamous cell carcinoma (A431 cell line) deep to the parotid region overlying the masseter muscle. We sacrificed the animals 1 to 3 weeks postinjection, once a visible tumor growth was confirmed. We then asked 10 OHNS trainees to excise the tumor with preservation of the facial nerves under a high-magnification dissecting microscope. The trainees graded the tasks in several areas of specific measures using a visual analogue scale (VAS) including 1) tumor texture, 2) surgical realism, 3) usefulness, and 4) difficulty of the task. RESULTS: Noticeable tumor growth occurred within 5 days following A431 cell injection and reached measureable size (0.5-1.5 cm) within 1 to 3 weeks. The tumor displaced the facial nerve laterally and medially, with few demonstrating infiltration of the nerve. VAS scores (± standard deviation) were 8.1 (± 1.7), 7.7 (± 2.5), 9.0 (± 0.9) and 6.6 (± 1.9) for tumor texture, surgical realism, usefulness, and the difficulty of the task, respectively. CONCLUSIONS: We demonstrate a novel, reliable and cost-effective mouse model for simulating tumor extirpation microsurgery with preservation of important neural structures. OHNS trainees have found this simulation model to be realistic, useful, and appropriately challenging.

Human sinonasal explant system for testing cytotoxicity of intranasal agents.

BACKGROUND: Intranasal agents play a critical role in the management of sinonasal disorders. There are ongoing efforts to develop new intranasal medications to combat sinonasal disease. Some intranasal agents, however, can have cytotoxic effects on human sinonasal tissue. In order to facilitate safe drug discovery, we developed a simple and reliable in vitro screening assay using human sinonasal explants to measure the cytotoxic profiles of intranasal agents. METHODS: We obtained sinonasal tissues from several regions of the nasal cavity from 12 patients undergoing endoscopic sinonasal surgery. These tissues were cultured on polytetrafluoroethylene membrane in serum-free growth medium. We determined the biochemical properties of these explants by measuring extracellular lactate dehydrogenase (LDH) levels and performing histological analyses over a period of 1 to 2 weeks. We then examined the cytotoxic profiles of 13 intranasal agents by measuring extracellular LDH levels using the human sinonasal explant system. RESULTS: Sinonasal explants exhibited a rapid reduction in extracellular LDH levels indicating stabilization in the culture environment within 2 days. Histological analysis showed maintenance of good cellular architecture for up to 2 weeks. The explants displayed intact epithelium and expressed ßIII-tubulin and Ki-67. Of the 13 tested intranasal agents, 1% zinc sulfate (ZnSO(4) ), 5% ZnSO(4) , and Zicam application were cytotoxic. CONCLUSION: Based on the unique biochemical properties of the human nasal explant culture system, we developed a simple and reliable in vitro screening assay to determine the cytotoxic profiles of various intranasal agents by examining extracellular LDH levels and histopathology.

Transorbital neuroendoscopic management of sinogenic complications involving the frontal sinus, orbit, and anterior cranial fossa.

Transnasal endoscopic surgery has remained at the forefront of surgical management of sinogenic complications involving the frontal sinus, orbit, and anterior skull base. However, the difficulty in accessing certain areas of these anatomical regions can potentially limit its use. Transorbital neuroendoscopic surgery (TONES) was recently introduced to transgress the limits of transnasal endoscopic surgery; the access that it provides could add additional surgical pathways for treating sinogenic complications involving the frontal sinus, orbit, and anterior cranial fossa. We describe a prospective series of 13 patients who underwent TONES for the management of various sinogenic complications, including epidural abscess, orbital abscess, and fronto-orbital mucocele or mucopyocele, as well as subperiosteal abscess presenting with orbital apex syndrome. The primary outcome measurement was the efficacy of TONES in treating these pathologies. TONES provided effective access to the frontal sinus, orbit, and the anterior cranial fossa. All patients demonstrated postoperative resolution of initial clinical symptoms with well-hidden surgical scars. There were no ophthalmologic complications or recurrence of pathology. Based on our experience, TONES appears to provide a valuable addition to the current surgical armamentarium for treating selected complications of sinusitis.

Zicam-induced damage to mouse and human nasal tissue.

Intranasal medications are used to treat various nasal disorders. However, their effects on olfaction remain unknown. Zicam (zinc gluconate; Matrixx Initiatives, Inc), a homeopathic substance marketed to alleviate cold symptoms, has been implicated in olfactory dysfunction. Here, we investigated Zicam and several common intranasal agents for their effects on olfactory function. Zicam was the only substance that showed significant cytotoxicity in both mouse and human nasal tissue. Specifically, Zicam-treated mice had disrupted sensitivity of olfactory sensory neurons to odorant stimulation and were unable to detect novel odorants in behavioral testing. These findings were long-term as no recovery of function was observed after two months. Finally, human nasal explants treated with Zicam displayed significantly elevated extracellular lactate dehydrogenase levels compared to saline-treated controls, suggesting severe necrosis that was confirmed on histology. Our results demonstrate that Zicam use could irreversibly damage mouse and human nasal tissue and may lead to significant smell dysfunction.

Developmental regulation of biglycan expression in muscle and tendon.

Biglycan is an extracellular ligand for the dystrophin-associated protein complex (DAPC) that is upregulated in both dystrophic and regenerating muscle. Biglycan also binds to collagen VI, mutations of which cause a congenital muscular dystrophy (Ullrich's; UCMD) that is also characterized by connective tissue abnormalities. The expression of biglycan in early development and postnatal ages has not been well characterized. Here we show that biglycan transcript levels peak at approximately 21 weeks' gestation in human fetal muscle. Immunocytochemical analysis of developing mouse muscle shows that biglycan can be detected in muscle as early as embryonic day (E)16 and is most abundant between postnatal day (P)1 and P7. Biglycan is also highly expressed in developing tendon, with maximal levels observed at E16-18. This robust tendon expression is correlated with a sharp peak in biglycan transcript levels in the hindlimb. Finally, at E18 collagen VI colocalizes with biglycan in tendon. These results suggest that biglycan has a particularly important function during muscle and connective tissue development. Moreover, biglycan may play a role in the pathogenesis of collagen VI-associated congenital muscular dystrophies.

Regulating fragile X gene transcription in the brain and beyond.

The past several years have seen remarkable growth in our understanding of the molecular processes underlying fragile X syndrome (FXS). Many studies have provided new insights into the regulation of Fmr1 gene expression and the potential function of its protein product. It is now known that the promoter elements modulating Fmr1 transcription involve a complex array of both cis and trans factors. Moreover, recent studies of epigenetic modification of chromatin have provided novel clues to unlocking the mysteries behind the regulation of Fmr1 expression. Here, we review the latest findings on the regulation of Fmr1 transcription.

AP-2alpha selectively regulates fragile X mental retardation-1 gene transcription during embryonic development.

Fragile X syndrome (FXS) is almost always caused by silencing of the FMR1 gene. The defects observed in FXS indicate that the normal FMR1 gene has a range of functions and plays a particularly prominent role during development. However, the mechanisms regulating FMR1 expression in vivo are not known. Here, we have tested the role of the transcription factor AP-2alpha in regulating Fmr1 expression. Chromatin immunoprecipitation showed that AP-2alpha associates with the Fmr1 promoter in vivo. Furthermore, Fmr1 transcript levels are reduced >4-fold in homozygous null AP-2alpha mutant mice at embryonic day 18.5 when compared with normal littermates. Notably, AP-2alpha exhibits a strong gene dosage effect, with heterozygous mice showing approximately 2-fold reduction in Fmr1 levels. Examination of conditional AP-2alpha mutant mice indicates that this transcription factor plays a major role in regulating Fmr1 expression in embryos, but not in adults. We further investigated the role of AP-2alpha in the developmental regulation of Fmr1 expression using the Xenopus animal cap assay. Over-expression of a dominant-negative AP-2alpha in Xenopus embryos led to reduced Fmr1 levels. Moreover, exogenous wild-type AP-2alpha rescued Fmr1 expression in embryos where endogenous AP-2alpha had been suppressed. We conclude that AP-2alpha associates with the Fmr1 promoter in vivo and selectively regulates Fmr1 transcription during embryonic development.