Marcelo B Antunes

University of Pennsylvania, Philadelphia, PA, United States

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Publications (27)40.87 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Although multiple etiologies contribute to the development of chronic rhinosinusitis (CRS), a common pathophysiological sequelae is ineffective sinonasal mucociliary clearance, leading to stasis of sinonasal secretions, with subsequent infection and/or persistent inflammation. Proper therapeutic intervention typically restores mucociliary activity, suggesting that the pathophysiological process(es) responsible for CRS-associated mucostasis may be reversible. We previously demonstrated a blunted response of CRS sinonasal cilia after purinergic stimulation. This study investigated whether the blunted ciliary response is unique to purinergic stimulation and addressed whether the blunted effect is primarily caused by local CRS-associated mediators or inherent genetic defects in ciliary function. A dual temperature-controlled perfusion chamber, differential interference contrast microscopy, and high-speed digital video were used to analyze both basal as well as cholinergic, adrenergic, and purinergic stimulation of cilia in human sinonasal mucosal explants. Additionally, enzymically dissociated sinonasal ciliated cells were maintained ex vivo in submersion, on glass coverslips, and assessed daily for purinergic ciliary beat frequency stimulation. Cholinergic and adrenergic stimulation generally were blunted in mucosal explants obtained from CRS patients. Ex vivo maintenance of samples demonstrated that the majority of CRS samples developed a stimulatory phenotype within 36 hours of culturing. CRS is a common debilitating disease principally affecting sinonasal epithelial function with a resultant diminution of mucociliary transport. Presently, little is known about how this disease process affects the sinonasal epithelial ciliated cells. Our data suggest that ciliary response to environmental insults is blunted in a reversible manner in CRS patients.
    American Journal of Rhinology 01/2007; 21(3):346-53. · 1.36 Impact Factor
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    ABSTRACT: Air-liquid interface cultures using murine tracheal respiratory epithelium have revolutionized the in vitro study of airway diseases. However, these cultures often are impractical because of the small number of respiratory epithelial cells that can be isolated from the mouse trachea. The ability to study ciliary physiology in vitro is of utmost importance in the research of chronic rhinosinusitis (CRS). Our hypothesis is that the murine nasal septum is a better source of ciliated respiratory epithelium to develop respiratory epithelial air-liquid interface models. Nasal septa and tracheas were harvested from 10 BALB/c mice. The nasal septa were harvested by using a simple and straightforward novel technique. Scanning electron microscopy was performed on all specimens. Cell counts of ciliated respiratory epithelial cells were performed at one standard magnification (1535x). Comparative analysis of proximal and distal trachea, midanterior and midposterior nasal septal epithelium, was performed. Independent cell counts revealed highly significant differences in the proportion of cell populations (p < 0.00001). Ciliated cell counts for the trachea (106.9 +/- 28) were an average of 38.7% of the total cell population. Nasal septal ciliated epithelial cells (277.5 +/- 16) comprised 90.1% of the total cell population. To increase the yield of respiratory epithelial cells harvested from mice, we have found that the nasal septum is a far superior source when compared with the trachea. The greater surface area and increased concentration of ciliated epithelial cells has the potential to provide an eightfold increase in epithelial cells for the development of air-liquid interface cultures.
    American Journal of Rhinology 01/2007; 21(5):533-7. · 1.36 Impact Factor
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    ABSTRACT: Topical antimicrobials are commonly used to treat Pseudomonas sinusitis after endoscopic sinus surgery. Despite their popularity, there is limited data in the literature to support its use. This study is the first to examine the effects of topical tobramycin in an animal model of Pseudomonas sinusitis. Pseudomonas aeruginosa sinusitis was induced in the maxillary sinus of New Zealand white rabbits. Study groups received various concentrations of topical tobramycin instilled through a single lumen catheter embedded within the maxillary sinus for 7 consecutive days. A control group received normal saline irrigation. Bacterial counts were measured from the nasal lavage after irrigation. The sinonasal complex was analyzed and a histological grading system was used to score the degree of infection at study end. Nasal lavage bacterial counts of the saline control group remained persistently elevated throughout the study. Introduction of increasing concentrations of topical tobramycin caused the bacterial counts to fall to zero by study end. There was a dose-dependent histological response in which increasing concentrations of tobramycin led to a marked reduction but not total elimination of inflammation within the mucosa and underlying bone. As opposed to normal saline irrigations, topical tobramycin led to a significant improvement in the degree of infection within an animal model of P. aeruginosa sinusitis. Despite the elimination of bacteria within the nasal lavage, there was a suggestion of a residual indolent infection as evidenced by persistent inflammation within the mucosa and underlying bone.
    American Journal of Rhinology 01/2007; 21(4):423-7. · 1.36 Impact Factor
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    ABSTRACT: Rhinosinusitis after functional endoscopic sinus surgery often is recalcitrant to conventional medical management. Topical therapies have been popularized as a method to deliver powerful medications to diseased mucosa while limiting systemic toxicity. The aim of this study was to develop an animal model that will provide objective data in studying the efficacy of topical medications and establish a platform for translation to human clinical trials. The maxillary sinus ostium of white rabbits was obstructed with a pledget through an antrostomy created in the anterior face of the maxilla. The sinus was inoculated with Pseudomonas aeruginosa (PAO1) and 7 days later the antrostomy was reopened, the ostial obstruction was removed, and a single lumen catheter was placed. Normal saline was irrigated through the catheter for 7 days in one group of rabbits while a control group received no irrigation. At the end of 7 days, the rabbits were euthanized, analyzed under light microscopy, and bacterial counts of the nasal lavage were determined. Sinusitis was confirmed in all rabbits 7 days after inoculation. Purulence, mucosal, and underlying bony inflammation persisted in both the control and the saline irrigation groups at study end. Nasal lavage bacterial counts were persistently elevated throughout the study period, indicative of bacterial viability. An animal model has been created for the study of topical medications in sinusitis. A novel catheter delivery system within an unoccluded maxillary sinus is described that will aid in efficacy studies of topical medications in the management of recalcitrant rhinosinusitis.
    American Journal of Rhinology 01/2007; 21(1):5-9. · 1.36 Impact Factor
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    ABSTRACT: Inverted papilloma (IP) is a benign but locally aggressive sinonasal tumor. Those localized to the maxillary sinus or medial maxillary wall have classically been removed through an external approach. In recent years, endoscopic removal has been advocated as an effective, minimally invasive approach. Successful endoscopic management is based on accurate intraoperative identification and complete resection of the tumor. The surgical management of the bone underlying the surface of an IP is less clearcut. Controversy exists as to whether the bony undersurface of an IP should be removed. In this article, histopathologic specimens and preoperative radiologic studies are prospectively examined to better understand the involvement of the bone underlying an inverted papilloma. A prospective study of patients with maxillary sinus IP treated with endoscopic or endoscopic-assisted resection over a 12-month period was conducted. Intraoperatively, the site of tumor attachment was identified, and a 1- to 2-cm wedge of bone with overlying tumor was removed en bloc and analyzed under light microscopy. Preoperative radiographic studies were analyzed with respect to bony changes in the area of the tumor pedicle. On histopathologic analysis, the bony surface underlying the IP was irregular with multiple bony crevices in all nine cases. In two cases (22% of specimens), an isolated rest of normal-appearingsalivary gland and/or mucosal tissue was seen embedded in the underlying bone. Radiographic osteitic bony changes were seen at site of tumor attachment in 100% of cases. The irregularity of the bony surface may hinder complete tumor removal because microscopic rests of mucosa can be hidden within the bony crevices. Intraoperative removal of the bony surface at the site of tumor attachment may ensure a more complete removal.
    The Laryngoscope 10/2006; 116(9):1617-20. · 1.98 Impact Factor
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    ABSTRACT: To assess the relative sharpness of osteotomes after multiple uses, routine maintenance, and sharpening. This prospective clinical study and mechanical model quantified the relative sharpness of identical osteotomes at baseline; after 3, 6, and 9 uses; and after sharpening techniques compared with osteotomes from hospital central supply. The Instron universal tester developed a force-displacement curve as the osteotome blade cut a standardized suture. Force required to cut the suture is inversely proportional to osteotome sharpness. For osteotomes 1, 2, and 3, dullness occurred after 9 uses (4.836 lb; P < .001), 6 uses (4.431 lb; P < .005), and 3 uses (4.093 lb; P < .02), respectively. Osteotome 1 was professionally sharpened after 9 uses and retested (3.156 lb); results were similar to those for an osteotome used 6 times (3.160 lb). Additional sharpening showed significantly poorer performance (7.737 lb; P < .001 at baseline and after 9 uses). Osteotome 3 was hand sharpened after 6 uses and retested (7.750 lb; baseline P < .001). Two osteotomes from central supply required almost twice the cutting force relative to the senior author's osteotomes. Although osteotome performance decreased significantly over time, professional sharpening only achieved results similar to an osteotome used 3 to 6 times. Further resharpening seems detrimental to performance. Surgeons may want to consider osteotomes disposable instruments.
    Archives of facial plastic surgery: official publication for the American Academy of Facial Plastic and Reconstructive Surgery, Inc. and the International Federation of Facial Plastic Surgery Societies 13(2):103-8. · 1.31 Impact Factor
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    ABSTRACT: Retinoic acid (RA) has been shown to enhance ciliary ultrastructure in regenerated sinus mucosa compared with controls. However, the functional status of the regenerated cilia has not been studied. Our objective was to evaluate the ciliary beat frequency (CBF) of regenerated sinus mucosa treated with topical RA in a rabbit model. Twelve rabbits underwent bilateral surgical stripping of the maxillary sinuses, followed by treatment with RA gel in the right side and an inert gel control in the left side. The rabbits were then killed at either 2 or 4 weeks, and CBF analysis of the regenerated mucosa was performed. Three unoperated rabbits were used to establish normative CBF data. Functional cilia were recovered from 11/12 RA-treated sinuses and 12/12 gel control sinuses. At 2 weeks postoperatively, the RA-treated sinuses showed an average CBF of 19.78 Hz, which was statistically comparable with the normal unoperated controls (p < 0.26). The inert gel-treated mucosa showed a CBF of 29.24 Hz, which was significantly elevated compared with normals (p < 0.05). At 4 weeks, ciliary activity persisted, but both RA-treated sinuses and gel controls showed elevated CBF compared with normals (p < 0.03). Topical RA placed in a demucosalized maxillary sinus yields functional cilia. RA appears to have a normalizing effect on CBF early in the mucosal wound healing process compared with control. This effect appears to be mitigated in later stages of wound healing. RA may be beneficial in enhancing morphological and functional aspects of regenerating cilia.
    American Journal of Rhinology 22(3):334-6. · 1.36 Impact Factor

Publication Stats

238 Citations
40.87 Total Impact Points

Institutions

  • 2007–2012
    • University of Pennsylvania
      • Department of Otorhinolaryngology - Head and Neck Surgery
      Philadelphia, PA, United States
  • 2011
    • NYU Langone Medical Center
      • Department of Otolaryngology
      New York City, NY, United States
  • 2008–2009
    • Hospital of the University of Pennsylvania
      • Department of Otorhinolaryngology - Head and Neck Surgery
      Philadelphia, Pennsylvania, United States