Emad Massoud

The health and resource utilization of Canadians with chronic rhinosinusitis.

To determine the impact of chronic rhinosinusitis (CRS) on the physical and mental health and health‐resource utilization of Canadians.

Proton-Coupled Oligopeptide Transporter (POT) Family Expression in Human Nasal Epithelium and Their Drug Transport Potential

The molecular and functional expression of peptide transporters (PEPT1 and PEPT2, PHT1, PHT2) in human nasal epithelium was investigated. Quantitative/reverse transcriptase polymerase chain reaction (qPCR/RT-PCR), Western blotting and indirect immuno-histochemistry were used to investigate the functional gene and protein expression for the transporters. Uptake and transport studies were performed using metabolically stable peptides [β-alanyl-L-lysyl-Nε-7-amino-4-methyl-coumarin-3-acetic acid (β-Ala-Lys-AMCA) and β-alanyl-L-histidine (carnosine)]. The effects of concentration, temperature, polarity, competing peptides, and inhibitors on peptide uptake and transport were investigated. PCR products corresponding to PEPT1 (150 bp), PEPT2 (127 bp), PHT1 (110 bp) and PHT2 (198 bp) were detected. Immunohistochemistry and Western blotting confirmed the functional expression of PEPT1 and PEPT2 genes. The uptake of β-Ala-Lys-AMCA was concentration-dependent and saturable (Vmax =4.1 ( 0.07 μmol/min/mg protein, Km = 0.6 ( 0.07 μM). The optimal pH for intracellular accumulation of β-Ala-Lys-AMCA was 6.5. Whereas dipeptides and carbonyl cyanide m-chlorophenylhydrazone (CCCP) significantly inhibited peptide uptake and transport, L-Phe had no effect on peptide transport. The permeation of β-alanyl-L-histidine was concentration-, direction-, and temperature-dependent. The uptake, permeation, qPCR/RT-PCR and protein expression data showed that the human nasal epithelium functionally expresses proton-coupled oligopeptide transporters.

Differential expression of organic cation transporters in normal and polyps human nasal epithelium: Implications for in vitro drug delivery studies

The aim of this study was to compare the expression of organic cation transporters (OCTs) in normal and polyps nasal epithelium. Primary cell cultures of human nasal epithelium (polyps and normal tissues) were compared by investigating the uptake of a fluorescent organic cation, [4-dimethylaminostyryl-N-methylpyridinium (4-Di-1-ASP)]. The effect of concentration, temperature, pH and competing inhibitors were investigated. Quantitative polymerase chain reaction (qPCR) was used to compare the OCTs gene expression levels in the cells. The K(m) (μM) and V(max) (μM/mg protein/15 min) for 4-Di-1-ASP uptake were higher in normal (K(m)=3031 ± 559.6, V(max)=70.8 ± 8.8) cells compared to polyps (K(m)=952.4 ± 207.8, V(max)=30.9 ± 2.1). qPCR results showed that OCT1-3 and organic cation/carnitine transporter 1-2 gene transcripts (OCTN1-2) were expressed in both normal and polyps cells at comparable levels, with OCT-3 having the highest expression level in both cultures. Kruskal-Wallis ANOVA showed that pH and specific inhibitors had similar effects on both normal and polyps cells (p>0.5). Similarly, OCTs and OCTNs gene expression levels were similar. This study showed that polyps biopsies can be used for isolating cells to study organic cation transporters in human nasal epithelium as no major functional or molecular differences relative to normal cells could be found.

Drug-Eluting Nasal Implants: Formulation, Characterization, Clinical Applications and Challenges

Chronic inflammation and infection of the nasal sinuses, also referred to as Chronic Rhinosinusitis (CRS), severely affects patients’ quality of life. Adhesions, ostial stenosis, infection and inflammation relapses complicate chronic sinusitis treatment strategies. Drug-eluting stents, packings or implants have been suggested as reasonable alternatives for addressing these concerns. This article reviewed potential drug candidates for nasal implants, formulation methods/optimization and characterization methods. Clinical applications and important considerations were also addressed. Clinically-approved implants (Propel™ implant, the Relieva stratus™ MicroFlow spacer, and the Sinu-Foam™ spacer) for CRS treatment was an important focus. The advantages and limitations, as well as future considerations, challenges and the need for additional research in the field of nasal drug implant development, were discussed.

An anatomically sound surgical simulation model for myringotomy and tympanostomy tube insertion

OBJECTIVE Myringotomy and tympanostomy tube insertion (MT) is a common surgical procedure. Although surgical simulation has proven to be an effective training tool, an anatomically sound simulation model for MT is lacking. We developed such a model and assessed its impact on the operating room performance of senior medical students. STUDY DESIGN Prospective randomized trial. METHODS A randomized single-blind controlled study of simulation training with the MT model versus no simulation training. Each participant was randomized to either the simulation model group or control group, after performing an initial MT procedure. Within two weeks of the first procedure, the students performed a second MT. All procedures were performed on real patients and rated with a Global Rating Scale by two attending otolaryngologists. Time to complete the MT was also recorded. RESULTS Twenty-four senior medical students were enrolled. Control and intervention groups did not differ at baseline on their Global Rating Scale score or time to complete the MT procedure. Following simulation training, the study group received significantly higher scores (P=.005) and performed the MT procedure in significantly less time (P=.034). The control group did not improve their performance scores (P>.05) or the time to complete the procedure (P>.05). CONCLUSION Our surgical simulation model shows promise for being a valuable teaching tool for MT for senior medical students. Such anatomically appropriate physical simulators may benefit teaching of junior trainees.

Specific aminopeptidases of excised human nasal epithelium and primary culture: a comparison of functional characteristics and gene transcripts expression.

OBJECTIVES To investigate whether growing human nasal epithelium as primary cultures alters aminopeptidase B (APB), aminopeptidase N (APN) and dipeptidyldipeptidase (DPPIV) metabolic characteristics, and mRNA gene transcript expression. METHODS The formation of 7-amino-methyl coumarin from specific substrates for APN (L-alanine-4-methyl-coumaryl-7-amide, APB (L-arginine-4-methyl-coumaryl-7-amide) and DPPIV (glycyl-L-proline-4-methyl-coumaryl-7-amide) was used to estimate the KM, Vmax and the effect of aminopeptidases inhibitors on the enzymes. Polymerase chain reaction was used to investigate gene expression. KEY FINDINGS Results of this study showed that: (1) both the excised tissues and primary cultures of human nasal epithelium expressed APN, APB and DPPIV activity; (2) the KM of APB, APN and DPPIV was not significantly different in cell and tissue homogenates; (3) except for APN, the Vmax was not significantly different in the two metabolism models; (4) there was no statistically significant difference in the behaviours of APB, APN and DPPIV in response to inhibition by puromycin and bestatin in the two models; (5) the mRNA transcripts that encode APB, APN and DPPIV were expressed in both cell culture and tissue homogenate. CONCLUSIONS Based on the results of this study, it may be concluded that nasal primary culture system is suitable for investigating peptide and protein metabolism and enzymatic stability in human nasal epithelium. Except for APN, the tissue culture conditions did not significantly alter the functional and molecular expression of the aminopeptidases.

Organic cation transporters in human nasal primary culture: expression and functional activity

BACKGROUND The majority of drugs cross epithelial cells by either passive diffusion or via carrier-mediated drug transporters. The aim of this study was to investigate the transport characteristics, protein expression and localization of organic cation transporters in human nasal epithelium. METHODS & RESULTS The expression, localization and transport characteristics of the transporters were investigated using permeation, PCR and immunohistochemistry. The uptake of 4-(4-(dimethylamino)styryl)-N-methylpyridinium iodide followed Michaelis-Menten kinetics. Its intracellular accumulation of the compound was inhibited by organic cation transporters (OCTs) and carnitine/organic cation transporter (OCTNs) inhibitors. Detected OCT1-3, OCTN1 and OCTN2 gene transcripts correlated with immunohistological staining for OCT1-3, OCTN1 and OCTN2 antibodies. Except for OCTN1, the antibodies were generally localized on the apical side of the epithelial cells. CONCLUSION Based on the immunohistochemical and uptake/transport studies, we conclude that the human nasal epithelium expresses OCT1-3, OCTN1 and OCTN2 transporters mainly on the apical side of the nasal cells.

Carotid artery visualization during anterior skull base surgery: a novel protocol for neuronavigation

Detailed knowledge of the vascular anatomy of the anterior skull base is critical to successful surgery in this area. Whereas conventional neuronavigational approaches combine MRI (± contrast) for tumor visualization and CT (± C) for bony and vascular anatomy, we describe the Canadian and Austrian experiences using a novel protocol integrating MR angiography (MRA) into surgical neuronavigation to provide superior visualization of the carotid arteries. The pre-operative imaging protocol employs a T1-weighted, 3D fast spoiled gradient echo MRI (± C) for soft tissue anatomy, a plain CT for bony anatomy, and a 3D time-of-flight MR angiography for carotid anatomy. The series are imported into the Medtronic StealthStation® TREON® Treatment Guidance System; during intra-operative neuronavigation, each series (MRI, CT, MRA) can be viewed individually, or layered and viewed as a composite image. Our protocol has important advantages. First, it provides detailed tissue, tumor, vascular and bony anatomy. Second, a contrast CT is not necessary; this is important, as numerous reports have highlighted the nephrotoxic nature of radiographic contrast material. Third, visualization of the carotid system is superior than can be obtained from CT angiography. We use this unique imaging protocol routinely for our endoscopic transsphenoidal surgeries to provide superior visualization of the carotid arteries during anterior skull base surgery.

Optimization of human nasal epithelium primary culture conditions for optimal proton oligopeptide and organic cation transporters expression in vitro

AIM To investigate the effect of key tissue culture conditions on cell growth, gene expression and functional uptake of peptide and organic cation transporter substrates in the human nasal epithelium (HNE). METHODS HNE were cultured on different growth surfaces (polystyrene plastic, collagen film, and hydrated collagen gel) and were maintained with three popular nasal tissue culture media supplements [DMEM/F12 supplemented with Ultroser(®) G (2%), FBS (10%) and NuSerum(®) (10%)], respectively. The expression of gene transcripts for organic cation and peptide transporters were screened using qPCR and substrate uptake studies. RESULTS Cell growth surface (polystyrene plastic surface, dried collagen film and hydrated collagen gel) did not significantly alter gene expression levels. However, Ultroser(®) G and FBS caused significant increase in PEPT1, PEPT2, PHT1, OCT3, and OCTN1 levels (~/=2-5-fold for FBS and 2-8-fold for Ultroser(®) G). In terms of the degree to which the supplements affected gene expression, the following observations were made: effect on OCTN1>PEPT2>OCT3>PHT1>PEPT1. Functional uptake of organic cation (4-Di-1-ASP) and peptide [β-Ala-Lys (AMCA)] transporter substrates was significantly lower in cells cultured with NuSerum(®) compared to Ultroser(®) G and FBS cultured cells (p>0.05). CONCLUSIONS Tissue culture media had a major effect on SLC gene expression levels of the human nasal epithelium in primary culture. Ultroser(®) G was identified as the most efficient culture supplement in maintaining SLC transporter expression under most culture conditions, whereas FBS appears to be an economical choice. We do not recommend the use of NuSerum(®) as a supplement for growing HNE for transport studies involving SLC transporters.

Cavernous sinus involvement in human papillomavirus associated oropharyngeal squamous cell carcinoma: case report of an atypical site of distant metastasis

BackgroundHPV-associated OSCC (HPV-OSCC) has been determined to be a distinct disease entity from non-HPV associated OSCC. Patients affected by HPV-OSCC generally have a more favourable prognosis, with improved rates of locoregional control and survival compared with their non-HPV counterparts. Despite this, HPV-OSCC has a similar rate of distant metastases. Interestingly, recent evidence has emerged that demonstrates more frequent atypical metastasis patterns when compared to non-HPV associated disease. To the best of our knowledge, this report describes the first case of a confirmed HPV-OSCC with distant metastasis to the cavernous sinus.Case PresentationA 62-year-old non-smoking male presented to the head and neck oncology clinic with a five-month history of enlarging right neck mass causing neck pain, dysphagia, and dysphonia. HPV-associated base of tongue squamous cell carcinoma (cT4aN2c) was diagnosed, and he was treated with primary chemoradiation. Shortly after treatment, he presented with progressive bilateral cranial nerve palsies including left cranial nerve III and right cranial nerve VI involvement. Imaging identified masses in the left cavernous sinus with extension of tumor into the sella and in the right cavernous sinus at the level of Dorello’s canal. Endoscopic Image Guided Transsphenoidal biopsy of the left sellar mass confirmed distant metastases from the previously treated HPV-OSCC primary to the cavernous sinus. The patient was palliated with carboplatin and paclitaxel.ConclusionThe presented report is the first documented case of confirmed HPV-associated oropharyngeal squamous cell carcinoma metastasizing to the cavernous sinus, and the only HPV confirmed head and neck cancer case to present with metastasis to the cavernous sinus and limited extracranial disease. This case demonstrates the importance of recognizing presentations of atypical metastasis that are possible in HPV-associated oropharyngeal cancer. Given the rarity of metastasis to this region, vigilance in follow up is instrumental in early identification and treatment for these patients.