Publications by authors named "Justin Morse"

17 Publications

  • Page 1 of 1

Effect of nasal suction catheter use on aerosol generation during endoscopic sinus surgery.

Int Forum Allergy Rhinol 2021 May 21. Epub 2021 May 21.

Department of Otolaryngology-Head and Neck Surgery, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.

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http://dx.doi.org/10.1002/alr.22812DOI Listing
May 2021

Is there still a role for cranialization in modern sinus surgery?

Curr Opin Otolaryngol Head Neck Surg 2021 Feb;29(1):53-58

Vanderbilt Department of Otolaryngology-Head and Neck Surgery, Vanderbilt University Medical Center, Nashville, Tennessee, USA.

Purpose Of Review: To give an overview of recently published literature on the indications and use of cranialization of the frontal sinuses.

Recent Findings: Recent studies on cranialization have evaluated its role in frontal sinus fractures, inflammatory disease, and tumors involving both the frontal sinus and anterior cranial fossa. Currently, a more conservative approach is favored with traumatic injury to the frontal sinus outflow tract, with multiple studies demonstrating outflow recanalization with observation alone. Similarly, advancements in endoscopic sinus surgical approaches allow the many posterior table fractures to be managed without cranialization. Severe inflammatory disease of the frontal sinus including giant mucoceles with frontal lobe compression have successfully been managed without cranialization in multiple studies suggesting an endoscopic surgical approach can be favored in these settings. Both benign and malignant tumors of the frontal sinus are managed without cranialization with select cases favoring an open approach with cranialization depending on tumor location. Malignant tumors of the frontal sinus are more likely to require cranialization as oncologic resection including margins can lead to large dural defects with significant tissue loss, which is unfavorable for more conservative reconstructive options.

Summary: Cranialization remains a necessary and indicated procedure in the appropriate clinical circumstances. A more conservative approach to frontal sinus fractures is warranted, with recent literature supporting similar outcomes and less morbidity. Inflammatory disease of the frontal sinus including giant mucoceles with frontal lobe compression can be managed without cranialization. Although most benign tumors can be resected via endoscopic approaches, cranialization remains a mainstay as part of the reconstructive plan after oncologic resection of malignant tumors involving the frontal sinus.
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http://dx.doi.org/10.1097/MOO.0000000000000691DOI Listing
February 2021

Treatment of Sinonasal Teratocarcinosarcoma: A Systematic Review and Survival Analysis.

Am J Rhinol Allergy 2021 Jan 20;35(1):132-141. Epub 2020 Sep 20.

Department of Otolaryngology, Vanderbilt University Medical Center, Nashville, Tennessee.

Background: Sinonasal teratocarcinosarcoma (SNTCS) is a rare malignancy of the anterior skull base with only 127 cases described in the English literature. Given the rarity of this tumor, new cases and analysis of published reports may assist in future management of SNTCS.

Objectives: 1) Describe findings from a systematic review of all available literature for malignant SNTCS including the clinical presentation, treatment modalities and outcomes. 2) Present two new cases of this rare anterior skull base tumor. 3) Compare treatment outcomes with respect to recurrence and mortality.

Methods: A systematic review of all English literature available in 2 comprehensive databases was conducted by two independent reviewers using PRISMA guidelines. 85 publications were identified. Each case was reviewed for demographics, treatment and survival, and aggregate treatment outcomes were compared using Kaplan-Meier analysis.

Results: A total of 64 articles meeting inclusion criteria were reported in the literature between 1977-2018. This represented a total of 127 patients, with a strong male predominance (83%) and mean age of 50 years (range 10-82). Mean follow-up was 21 months. Recurrence rate was 38%, with mean survival at 2 years of 55%. Almost all patients underwent surgery as a primary treatment modality (90%). The majority of cases were treated with multimodal therapy, with 55% receiving surgery and radiation and 20% receiving surgery with adjuvant chemoradiation. Kaplan-Meier analysis demonstrated a significant survival advantage for patients treated with combined therapy compared to surgery alone (p < 0.001) but did not show differences in recurrence (p = 0.085).

Conclusion: Two-year survival rates for SNTCS are 55%. Multimodality treatment outcomes appear to be superior to surgery alone based on the published data of this rare skull base tumor, although heterogeneity of treatment methods and reporting bias limits the generalizability of these findings.
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http://dx.doi.org/10.1177/1945892420959585DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8258305PMC
January 2021

Septal Perfoplasty for Management of Symptomatic Nasal Septal Perforation: An Alternative to Surgical Closure.

Facial Plast Surg Aesthet Med 2021 Mar-Apr;23(2):103-109. Epub 2020 Aug 10.

Department of Otolaryngology-Head and Neck Surgery, Vanderbilt University Medical Center, Nashville, Tennessee, USA.

Symptomatic septal perforations are often difficult to manage and can have a significant impact on patient quality of life. Available surgical techniques for repair have demonstrated a varying rate of success, presenting a need for reliable interventions targeting symptom control. To describe the modified surgical technique here termed septal perfoplasty. To demonstrate that creation of favorable septal perforation characteristics is effective in managing symptoms and improving patient quality of life. A retrospective review of the medical record was performed of patients who underwent the procedure of interest between July 1, 2006 and October 1, 2019 at Vanderbilt University Medical Center. All patients with symptomatic septal perforation who underwent septal perfoplasty within the timeframe reviewed were included. Septal perfoplasty was standardly performed in combination with turbinate reduction in all cases. This was combined with other indicated procedures for chronic sinusitis, repair of vestibular stenosis or nasal deformity. Creation of a well-mucosalized septal perforation, combined with patient-reported acceptable symptom control, was the primary outcome. Secondary outcomes include time to resolution, duration of follow-up, postsurgical complications, and need for further intervention. Twenty patients (70% female; mean [range] age, 45.8 [15-72] years) underwent septal perfoplasty over the course of 13 years. The most common etiology of perforation was trauma (40%), presenting symptom was crusting (95%), and size of perforation repaired was large (60%). Mean follow-up was 37.6 months (range, 1-153 months). Overall, favorable perforation characteristics were created in 95% of cases by the first postoperative appointment. Acceptable symptomatic control was achieved in 18 out of 20 patients (90%), with a median time to improvement of 66 days. Eight patients required additional surgery to address chronic sinusitis or vestibular stenosis. Two patients experienced postoperative infections, treated conservatively with antibiotics. Septal perfoplasty is a safe, simple, and effective method for management of symptomatic nasal septal perforation, which provides an alternative to more complicated interventions with comparable rates of symptomatic resolution. This procedure should particularly be considered for patients in which difficult repair is anticipated.
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http://dx.doi.org/10.1089/fpsam.2020.0155DOI Listing
August 2020

Spontaneous Rupture of the Internal Carotid Artery Owing to an Aberrant Styloid Process in an Identical Twin.

JAMA Otolaryngol Head Neck Surg 2020 04;146(4):385-386

Division of Head and Neck, Department of Otolaryngology-Head and Neck Surgery, Vanderbilt University Medical Center, Nashville, Tennessee.

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http://dx.doi.org/10.1001/jamaoto.2019.4790DOI Listing
April 2020

Elongation factor-Tu can repetitively engage aminoacyl-tRNA within the ribosome during the proofreading stage of tRNA selection.

Proc Natl Acad Sci U S A 2020 02 5;117(7):3610-3620. Epub 2020 Feb 5.

Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY 10065;

The substrate for ribosomes actively engaged in protein synthesis is a ternary complex of elongation factor Tu (EF-Tu), aminoacyl-tRNA (aa-tRNA), and GTP. EF-Tu plays a critical role in mRNA decoding by increasing the rate and fidelity of aa-tRNA selection at each mRNA codon. Here, using three-color single-molecule fluorescence resonance energy transfer imaging and molecular dynamics simulations, we examine the timing and role of conformational events that mediate the release of aa-tRNA from EF-Tu and EF-Tu from the ribosome after GTP hydrolysis. Our investigations reveal that conformational changes in EF-Tu coordinate the rate-limiting passage of aa-tRNA through the accommodation corridor en route to the peptidyl transferase center of the large ribosomal subunit. Experiments using distinct inhibitors of the accommodation process further show that aa-tRNA must at least partially transit the accommodation corridor for EF-Tu⋅GDP to release. aa-tRNAs failing to undergo peptide bond formation at the end of accommodation corridor passage after EF-Tu release can be reengaged by EF-Tu⋅GTP from solution, coupled to GTP hydrolysis. These observations suggest that additional rounds of ternary complex formation can occur on the ribosome during proofreading, particularly when peptide bond formation is slow, which may serve to increase both the rate and fidelity of protein synthesis at the expense of GTP hydrolysis.
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http://dx.doi.org/10.1073/pnas.1904469117DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7035488PMC
February 2020

Outcomes of Nasal Septal Perforation Repair Using Combined Temporoparietal Fascia Graft and Polydioxanone Plate Construct.

JAMA Facial Plast Surg 2019 Jul;21(4):319-326

Department of Otolaryngology-Head and Neck Surgery, Vanderbilt University School of Medicine, Nashville, Tennessee.

Importance: Numerous techniques are used for septal perforation repair, yet success rates remain variable. Few studies have evaluated the effectiveness of interposition grafts of polydioxanone plates combined with a temporoparietal fascia graft for septal perforation repair.

Objective: To investigate and describe the use of interposition grafts of polydioxanone plates combined with a temporoparietal fascia graft for septal perforation repair and the expansion of this technique to patients with more challenging comorbidities, including granulomatosis with polyangiitis.

Design, Setting, And Participants: A retrospective medical record review was performed of patients who underwent septal perforation repair using interposition grafts of polydioxanone plates combined with a temporoparietal fascia graft from January 1, 2015, to July 1, 2018, at Vanderbilt University Medical Center and from January 1, 2017, to July 1, 2018, at the University of Iowa.

Intervention: All patients underwent septal perforation repair with interposition grafts of polydioxanone plates and a temporoparietal fascia graft.

Main Outcomes And Measures: Assessing closure of septal perforation was the primary outcome. Secondary outcomes were resolution of presenting symptoms of septal perforation, area of perforation, length of postoperative stent and silastic sheeting placement, postoperative complications and resolution, and duration of follow-up. Preoperative and postoperative Nasal Obstruction Symptom Evaluation (NOSE) scores were assessed.

Results: A total of 17 patients (12 women and 5 men; mean [SD] age, 45 [15] years) were included. The causes of perforations were iatrogenic (9 [53%]), rheumatologic (2 [12%]), and unknown or idiopathic (6 [35%]). Patients most commonly presented with nasal crusting (12 [71%]), whistling (9 [53%]), nasal obstruction (9 [53%]), and epistaxis (5 [29%]). Mean (SD) perforation size was 0.99 (1.04) cm2. Mean (SD) postoperative follow-up was 6.1 (4.1) months. A total of 15 patients (88%) had complete resolution of presenting symptoms at last follow-up. All perforations were closed with overlying mucosa at the most recent follow-up examination. Nine of 17 patients completed both preoperative and postoperative NOSE. There was a significant difference between the mean (SD) preoperative and postoperative NOSE scores (62.78 [27.74] vs 17.78 [15.83]; P = .004).

Conclusions And Relevance: Repair of symptomatic nasal septal perforations using a temporoparietal fascia graft combined with a polydioxanone plate was associated with positive outcomes. Repair of septal perforations caused by rheumatologic disease, including granulomatosis with polyangiitis, can be considered for repair using this technique. Resolution of symptoms appeared to be clinically more meaningful in evaluation of septal perforation repair than rate of perforation closure, and the NOSE scale has the potential to serve as an objective corroboration to patient-reported postoperative outcomes.

Level Of Evidence: 4.
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http://dx.doi.org/10.1001/jamafacial.2019.0020DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6583828PMC
July 2019

Patterns of olfactory dysfunction in chronic rhinosinusitis identified by hierarchical cluster analysis and machine learning algorithms.

Int Forum Allergy Rhinol 2019 03 28;9(3):255-264. Epub 2018 Nov 28.

Department of Otolaryngology-Head and Neck Surgery, Vanderbilt University Medical Center, Nashville, TN.

Background: Olfactory dysfunction is a common symptom of chronic rhinosinusitis (CRS). We previously identified several cytokines potentially linked to smell loss, potentially supporting an inflammatory etiology for CRS-associated olfactory dysfunction. In the current study we sought to validate patterns of olfactory dysfunction in CRS using hierarchical cluster analysis, machine learning algorithms, and multivariate regression.

Methods: CRS patients undergoing functional endoscopic sinus surgery were administered the Smell Identification Test (SIT) preoperatively. Mucus was collected from the middle meatus using an absorbent polyurethane sponge and 17 inflammatory mediators were assessed using a multiplexed flow-cytometric bead assay. Hierarchical cluster analysis was performed to characterize inflammatory patterns and their association with SIT scores. The random forest approach was used to identify cytokines predictive of olfactory function.

Results: One hundred ten patients were enrolled in the study. Hierarchical cluster analysis identified 5 distinct CRS clusters with statistically significant differences in SIT scores observed between individual clusters (p < 0.001). A majority of anosmic patients were found in a single cluster, which was additionally characterized by nasal polyposis (100%) and a high incidence of allergic fungal rhinosinusitis (50%) and aspirin-exacerbated respiratory disease (AERD) (33%). A random forest approach identified a strong association between olfaction and the cytokines interleukin (IL)-5 and IL-13. Multivariate modeling identified AERD, computed tomography (CT) score, and IL-2 as the variables most predictive of olfactory function.

Conclusion: Olfactory dysfunction is associated with specific CRS endotypes characterized by severe nasal polyposis, tissue eosinophilia, and AERD. Mucus IL-2 levels, CT score, and AERD were independently associated with smell loss.
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http://dx.doi.org/10.1002/alr.22249DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6397071PMC
March 2019

Chronic rhinosinusitis in elderly patients is associated with an exaggerated neutrophilic proinflammatory response to pathogenic bacteria.

J Allergy Clin Immunol 2019 03 22;143(3):990-1002.e6. Epub 2018 Nov 22.

Department of Otolaryngology-Head and Neck Surgery, Vanderbilt University Medical Center, Nashville, Tenn. Electronic address:

Background: Potential effects of aging on chronic rhinosinusitis (CRS) pathophysiology have not been well defined but might have important ramifications given a rapidly aging US and world population.

Objective: The goal of the current study was to determine whether advanced age is associated with specific inflammatory CRS endotypes or immune signatures.

Methods: Levels of 17 mucus cytokines and inflammatory mediators were measured in 147 patients with CRS. Hierarchical cluster analysis was used to identify and characterize inflammatory CRS endotypes, as well as to determine whether age was associated with specific immune signatures.

Results: A CRS endotype with a proinflammatory neutrophilic immune signature was enriched in older patients. In the overall cohort patients 60 years and older had increased mucus levels of IL-1β, IL-6, IL-8, and TNF-α when compared with their younger counterparts. Increases in levels of proinflammatory cytokines were associated with both tissue neutrophilia and symptomatic bacterial infection/colonization in aged patients.

Conclusions: Aged patients with CRS have a unique inflammatory signature that corresponds to a neutrophilic proinflammatory response. Neutrophil-driven inflammation in aged patients with CRS might be less likely to respond to corticosteroids and might be closely linked to chronic microbial infection or colonization.
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http://dx.doi.org/10.1016/j.jaci.2018.10.056DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6408962PMC
March 2019

Oropharyngeal Injury From Spontaneous Combustion of a Lithium-ion Battery: A Case Report.

Laryngoscope 2019 01 8;129(1):45-48. Epub 2018 Sep 8.

Department of Otolaryngology-Head and Neck Surgery, Vanderbilt University School of Medicine, Nashville, Tennessee, U.S.A.

Lithium-ion batteries have been used for more than 20 years, most recently to power handheld devices including cellphones and electronic nicotine-delivery systems. They have garnered significant media attention due to thermal-related injuries occurring after spontaneous combustion. Spontaneous combustion of a lithium-ion battery occurs due to a process that is referred to as the thermal runaway effect. Here, we review the case of a 25-year-old female with severe oropharyngeal and upper aerodigestive thermal injuries after spontaneous combustion of a lithium-ion battery in a flashlight. We discuss the associated management and provide a review of the literature detailing similar injuries. Laryngoscope, 129:45-48, 2019.
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http://dx.doi.org/10.1002/lary.27275DOI Listing
January 2019

Laryngeal Cryptococcoma Resulting in Airway Compromise in an Immunocompetent Patient: A Case Report.

Laryngoscope 2019 04 27;129(4):926-929. Epub 2018 Aug 27.

Department of Otolaryngology-Head and Neck Surgery, Vanderbilt University School of Medicine, Nashville, Tennessee, U.S.A.

Cryptococcus neoformans is a yeast than can result in isolated or disseminated infections. This case report describes an immunocompetent patient presenting with airway obstruction secondary to laryngeal crypotococcoma, mimicking a laryngeal malignancy, and describes associated management. A 68-year-old immunocompetent female with a new positron emission tomography-avid laryngeal lesion was intubated after acute respiratory decompensation. Airway evaluation revealed diffuse mucosal changes throughout the endolarynx with significant loss of normal native tissue architecture. Operative biopsy confirmed infection of C neoformans. The patient was treated with extended-course fluconazole. This case reinforces characteristic physical and histologic findings described for laryngeal cryptococcal infection. Laryngoscope, 129:926-929, 2019.
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http://dx.doi.org/10.1002/lary.27456DOI Listing
April 2019

Up-regulation of Intracellular Calcium Handling Underlies the Recovery of Endotoxemic Cardiomyopathy in Mice.

Anesthesiology 2017 06;126(6):1125-1138

From the Department of Medicine, Section of Cardiovascular Medicine, Boston University Medical Center, Boston, Massachusetts (J.C.M., J.H., N.K., E.J.M., D.A.S., W.S.C., I.A.H.); Department of Radiology, Boston University Medical Center, Boston, Massachusetts (E.J.M.); Department of Anesthesiology, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts (I.A.H.); and Harvard University Medical School, Boston, Massachusetts (I.A.H.).

Background: In surviving patients, sepsis-induced cardiomyopathy is spontaneously reversible. In the absence of any experimental data, it is generally thought that cardiac recovery in sepsis simply follows the remission of systemic inflammation. Here the authors aimed to identify the myocardial mechanisms underlying cardiac recovery in endotoxemic mice.

Methods: Male C57BL/6 mice were challenged with lipopolysaccharide (7 μg/g, intraperitoneally) and followed for 12 days. The authors assessed survival, cardiac function by echocardiography, sarcomere shortening, and calcium transients (with fura-2-acetoxymethyl ester) in electrically paced cardiomyocytes (5 Hz, 37°C) and myocardial protein expression by immunoblotting.

Results: Left ventricular ejection fraction, cardiomyocyte sarcomere shortening, and calcium transients were depressed 12 h after lipopolysaccharide challenge, started to recover by 24 h (day 1), and were back to baseline at day 3. The recovery of calcium transients at day 3 was associated with the up-regulation of the sarcoplasmic reticulum calcium pump to 139 ± 19% (mean ± SD) of baseline and phospholamban down-regulation to 35 ± 20% of baseline. At day 6, calcium transients were increased to 123 ± 31% of baseline, associated with increased sarcoplasmic reticulum calcium load (to 126 ± 32% of baseline, as measured with caffeine) and inhibition of sodium/calcium exchange (to 48 ± 12% of baseline).

Conclusions: In mice surviving lipopolysaccharide challenge, the natural recovery of cardiac contractility was associated with the up-regulation of cardiomyocyte calcium handling above baseline levels, indicating the presence of an active myocardial recovery process, which included sarcoplasmic reticulum calcium pump activation, the down-regulation of phospholamban, and sodium/calcium exchange inhibition.
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http://dx.doi.org/10.1097/ALN.0000000000001627DOI Listing
June 2017

Juvenile Swine Surgical Alveolar Cleft Model to Test Novel Autologous Stem Cell Therapies.

Tissue Eng Part C Methods 2015 Sep;21(9):898-908

1 Plastic Surgery, Cincinnati Children's Hospital Medical Center , Cincinnati, Ohio.

Reconstruction of craniofacial congenital bone defects has historically relied on autologous bone grafts. Engineered bone using mesenchymal stem cells from the umbilical cord on electrospun nanomicrofiber scaffolds offers an alternative to current treatments. This preclinical study presents the development of a juvenile swine model with a surgically created maxillary cleft defect for future testing of tissue-engineered implants for bone generation. Five-week-old pigs (n=6) underwent surgically created maxillary (alveolar) defects to determine critical-sized defect and the quality of treatment outcomes with rib, iliac crest cancellous bone, and tissue-engineered scaffolds. Pigs were sacrificed at 1 month. Computed tomography scans were obtained at days 0 and 30, at the time of euthanasia. Histological evaluation was performed on newly formed bone within the surgical defect. A 1 cm surgically created defect healed with no treatment, the 2 cm defect did not heal. A subsequently created 1.7 cm defect, physiologically similar to a congenitally occurring alveolar cleft in humans, from the central incisor to the canine, similarly did not heal. Rib graft treatment did not incorporate into adjacent normal bone; cancellous bone and the tissue-engineered graft healed the critical-sized defect. This work establishes a juvenile swine alveolar cleft model with critical-sized defect approaching 1.7 cm. Both cancellous bone and tissue engineered graft generated bridging bone formation in the surgically created alveolar cleft defect.
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http://dx.doi.org/10.1089/ten.TEC.2014.0646DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4553376PMC
September 2015

Lipopolysaccharide and cytokines inhibit rat cardiomyocyte contractility in vitro.

J Surg Res 2015 Feb 22;193(2):888-901. Epub 2014 Sep 22.

Cardiovascular Medicine Section, Department of Medicine, Boston University Medical Center, Boston, Massachusetts.

Background: Sepsis-induced cardiomyopathy (SIC) is thought to be the result of detrimental effects of inflammatory mediators on the cardiac muscle. Here we studied the effects of prolonged (24 ± 4 h) exposure of adult rat ventricular myocytes (ARVM) to bacterial lipopolysaccharide (LPS) and inflammatory cytokines tumor necrosis factor (TNF) and interleukins-1 (IL-1) and IL-6.

Materials And Methods: We measured sarcomere shortening (SS) and cellular calcium (Ca(2+)) transients (ΔCai, with fura-2 AM) in isolated cardiomyocytes externally paced at 5 Hz at 37°C.

Results: SS decreased after incubation with LPS (100 μg/mL), IL-1 (100 ng/mL), and IL-6 (30 ng/mL), but not with lesser doses of these mediators, or TNF (10-100 ng/mL). A combination of LPS (100 μg/mL), TNF, IL-1, and IL-6 (each 100 ng/mL; i.e., "Cytomix-100") induced a maximal decrease in SS and ΔCai. Sarcoplasmic reticulum (SR) Ca(2+) load (CaSR, measured with caffeine) was unchanged by Cytomix-100; however, SR fractional release (ΔCai/CaSR) was decreased. Underlying these effects, Ca(2+) influx into the cell (via L-type Ca(2+) channels, LTCC) and Ca(2+) extrusion via Na(+)/Ca(2+) exchange were decreased by Cytomix-100. SR Ca(2+) pump (SERCA) (SR Ca(2+) ATPase) was not affected.

Conclusions: Prolonged exposure of ARVM to a mixture of LPS and inflammatory cytokines inhibits cell contractility. The effect is mediated by the inhibition of Ca(2+) influx via LTCC, and partially opposed by the inhibition of Na(+)/Ca(2+) exchange. Because both mechanisms are commonly seen in animal models of SIC, we conclude that prolonged challenge with Cytomix-100 of ARVM may represent an accurate in vitro model for SIC.
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http://dx.doi.org/10.1016/j.jss.2014.09.015DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4268427PMC
February 2015

An experimental and numerical investigation of head dynamics due to stick impacts in girls' lacrosse.

Ann Biomed Eng 2014 Dec 15;42(12):2501-11. Epub 2014 Aug 15.

Center for Biomedical Engineering, Brown University, Providence, RI, USA.

A method of investigating head acceleration and intracranial dynamics from stick impacts in girls' and women's lacrosse was developed using headform impact experiments and a finite element head model. Assessing the likelihood of head injury due to stick-head impacts is of interest in girls' and women's lacrosse due to the current lack of head protection during play. Experimental and simulation data were compared to characterize the head acceleration caused by stick-head impacts. Validation against cadaver head impact experiments ensures that the finite element model, with its relatively simple material properties, can provide means to develop a better understanding of the intracranial dynamics during lacrosse stick impacts. Our numerical results showed the peak acceleration at the center of gravity increased linearly with impact force, and was generally in agreement with the experimental data. von Mises stresses and peak principal strains, two common literature injury indicators, were examined within the finite element model, and peak values were below the previously reported thresholds for mild traumatic brain injury. By reconstructing typical in-game, unprotected stick-head impacts, this investigation lays the foundation for a quantitative methodology of injury prediction in girls' and womens' lacrosse.
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http://dx.doi.org/10.1007/s10439-014-1091-8DOI Listing
December 2014

SERCA Cys674 sulphonylation and inhibition of L-type Ca2+ influx contribute to cardiac dysfunction in endotoxemic mice, independent of cGMP synthesis.

Am J Physiol Heart Circ Physiol 2013 Oct 9;305(8):H1189-200. Epub 2013 Aug 9.

Cardiovascular Medicine Section, Department of Medicine, Boston University Medical Center, Boston, Massachusetts;

The goal of this study was to identify the cellular mechanisms responsible for cardiac dysfunction in endotoxemic mice. We aimed to differentiate the roles of cGMP [produced by soluble guanylyl cyclase (sGC)] versus oxidative posttranslational modifications of Ca(2+) transporters. C57BL/6 mice [wild-type (WT) mice] were administered lipopolysaccharide (LPS; 25 μg/g ip) and euthanized 12 h later. Cardiomyocyte sarcomere shortening and Ca(2+) transients (ΔCai) were depressed in LPS-challenged mice versus baseline. The time constant of Ca(2+) decay (τCa) was prolonged, and sarcoplasmic reticulum Ca(2+) load (CaSR) was depressed in LPS-challenged mice (vs. baseline), indicating decreased activity of sarco(endo)plasmic Ca(2+)-ATPase (SERCA). L-type Ca(2+) channel current (ICa,L) was also decreased after LPS challenge, whereas Na(+)/Ca(2+) exchange activity, ryanodine receptors leak flux, or myofilament sensitivity for Ca(2+) were unchanged. All Ca(2+)-handling abnormalities induced by LPS (the decrease in sarcomere shortening, ΔCai, CaSR, ICa,L, and τCa prolongation) were more pronounced in mice deficient in the sGC main isoform (sGCα1(-/-) mice) versus WT mice. LPS did not alter the protein expression of SERCA and phospholamban in either genotype. After LPS, phospholamban phosphorylation at Ser(16) and Thr(17) was unchanged in WT mice and was increased in sGCα1(-/-) mice. LPS caused sulphonylation of SERCA Cys(674) (as measured immunohistochemically and supported by iodoacetamide labeling), which was greater in sGCα1(-/-) versus WT mice. Taken together, these results suggest that cardiac Ca(2+) dysregulation in endotoxemic mice is mediated by a decrease in L-type Ca(2+) channel function and oxidative posttranslational modifications of SERCA Cys(674), with the latter (at least) being opposed by sGC-released cGMP.
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http://dx.doi.org/10.1152/ajpheart.00392.2012DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3798783PMC
October 2013

Effects of connective tissue growth factor on the regulation of elastogenesis in human umbilical cord-derived mesenchymal stem cells.

Ann Plast Surg 2013 May;70(5):568-73

Department of Plastic and Reconstructive Surgery, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA.

Background: A key to clinical microtia reconstruction is construct flexibility. The most significant current limitation to engineered elastic cartilage is maintaining an elastic phenotype, which is principally dependent on elastin production (although other parameters, including maintenance of a ratio above 1 for collagens II to I, minimizing collagen X content, and presence of adequate matrix fibrillin for elastin binding, all play supporting roles). Connective tissue growth factor (CTGF), a compound secreted by chondrocytes, has been shown to promote an elastic phenotype in mature rabbit chondrocytes; however, CTGF effect on undifferentiated mesenchymal stem cells (MSCs) has not been characterized. The principal aim of this study is to analyze CTGF effect on elastin production in umbilical cord (UC)-derived MSCs and to determine optimal timing of treatment to maximize elastin production.

Methods: Human UCMSCs (hUCMSCs) were isolated from Wharton jelly using an explant technique, grown to passage 3, seeded onto nanofiber scaffolds, and chondroinduced for 21 days. Nanofiber scaffolds were electrospun using solubilized poly L-lactide/D-lactide/glycolide (PLGA). Chondrogenic media was supplemented with 25 μg/mL CTGF starting at day 0 or 7. Messenger RNA (mRNA) for Collagen I, II, X, fibrillin, and elastin was quantified by RT-PCR; glycosaminoglycan (GAG) matrix deposition was assessed and normalized by cellular DNA content. Elastin protein was assessed by Western blot analysis. All experiments were performed in triplicate with MSCs from 4 distinct cords. Multiway analysis of variance with Newman-Keuls post test was used to determine statistical significance.

Results: Connective tissue growth factor treatment results in increased GAG/DNA ratio; the differentiation index was maintained above 1 in all conditions, with increased collage II noted at days 7 and 14 in CTGF conditions; no difference in collagen X or fibrillin mRNA was noted. Increased elastin mRNA and protein were noted at day 14 in conditions treated with CTGF at day 7 after differentiation.

Conclusions: Connective tissue growth factor leads to maximal elastin increase in UCMSCs after 7 days of chondroinduction and not in undifferentiated MSCs. With appropriately timed treatment, CTGF may be a useful adjunct in maintaining an elastic cartilage phenotype in engineered cartilage from human UCMSCs.
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http://dx.doi.org/10.1097/SAP.0b013e31827ed6f4DOI Listing
May 2013
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