Relapse of Non-Hodgkin's Lymphoma Involving the Trachea: Acute Subglottic Obstruction.

Relapsing lymphoma involving the trachea causing tracheal obstruction is exceedingly uncommon. Despite its rarity, it should be considered in the differential diagnosis when a patient with known lymphoma presents with signs of airway obstruction such as stridor. We report an unusual case of relapsing non-Hodgkin's lymphoma with tracheal involvement in a 57-year-old female and review the relevant literature. It is highly unusual for relapsing lymphoma to involve the trachea causing tracheal obstruction. Despite its rarity, it can present with life-threatening airway obstruction which may be rapidly progressive requiring immediate surgical intervention such as tracheostomy.

Structure and properties of biomedical films prepared from aqueous and acidic silk fibroin solutions.

Silk fibroin films are promising materials for a range of biomedical applications. To understand the effects of casting solvents on film properties, we used water (W), formic acid (FA), and trifluoroacetic acid (TFA) as solvents. We characterized molecular weight, secondary structure, mechanical properties, and degradation behavior of cast films. Significant degradation of fibroin was observed for TFA-based film compared to W and TA-based films when analyzed by SDS-PAGE. Fibroin degradation resulted in a significant reduction in tensile strength and modulus of TFA-based films. Compared to water, TFA-based films demonstrated lower water solubility (19.6% vs. 62.5% in 12 h) despite having only a marginal increase in their ß-sheet content (26.9% vs. 23.7%). On the other hand, FA-based films with 34.3% ß-sheet were virtually water insoluble. Following solubility treatment, ß-sheet content in FA-based films increased to 50.9%. On exposure to protease XIV, water-annealed FA-based films lost 74% mass in 22 days compared to only 30% mass loss by ethanol annealed FA films. This study demonstrated that a small variation in the ß-sheet percentage and random coil conformations resulted in a significant change in the rates of enzymatic degradation without alteration to their tensile properties. The film surface roughness changed with the extent of enzymatic hydrolysis.

Phenotypic and genotypic profile of human tympanic membrane derived cultured cells.

The human tympanic membrane (hTM), known more commonly as the eardrum, is a thin, multi-layered membrane that is unique in the body as it is suspended in air. When perforated, the hTM's primary function of sound-pressure transmission is compromised. For the purposes of TM reconstruction, we investigated the phenotype and genotype of cultured primary cells derived from hTM tissue explants, compared to epithelial (HaCaT cells) and mesenchymal (human dermal fibroblasts (HDF)) reference cells. Epithelium-specific ets-1 (ESE-1), E-cadherin, keratinocyte growth factor-1 (KGF-1/FGF-7), keratinocyte growth factor-2 (KGF-2/FGF10), fibroblast growth factor receptor 1 (FGFR1), variants of fibroblast growth factor receptor 2 (FGFR2), fibroblast surface protein (FSP), and vimentin proteins were used to assess the phenotypes of all cultured cells. Wholemount and paraffin-embedded hTM tissues were stained with ESE-1 and E-cadherin proteins to establish normal epithelial-specific expression patterns within the epithelial layers. Immunofluorescent (IF) cell staining of hTM epithelial cells (hTMk) demonstrated co-expression of both epithelial- and mesenchymal-specific proteins. Flow cytometry (FCM) analysis further demonstrated co-expression of these epithelial and mesenchymal-specific proteins, indicating the subcultured hTMk cells possessed a transitional phenotype. Gene transcript analysis of hTMk cells by reverse transcriptase polymerase chain reaction (RT-PCR) revealed a down regulation of ESE-1, E-cadherin, FGFR2, variant 1 and variant 2 (FGFR2v1 and FGFR2v2) between low and high passages, and up-regulation of KGF-1, KGF-2, and FGFR1. All results indicate a gradual shift in cell phenotype of hTMk-derived cells from epithelial to mesenchymal.

Preliminary results of the application of a silk fibroin scaffold to otology.

The surgical treatment to repair chronic tympanic membrane perforations is myringoplasty. Although multiple autologous grafts, allografts, and synthetic graft materials have been used over the years, no single graft material is superior for repairing all perforation types. Recently, the remarkable properties of silk fibroin protein have been studied, with biomedical and tissue engineering applications in mind, across a number of medical and surgical disciplines. The present study examines the use of silk fibroin for its potential suitability as an alternative graft in myringoplasty surgery by investigating the growth and proliferation of human tympanic membrane keratinocytes on a silk fibroin scaffold in vitro. Light microscopy, immunofluorescent staining, and confocal imaging all reveal promising preliminary results. The biocompatibility, transparency, stability, high tensile strength, and biodegradability of fibroin make this biomaterial an attractive option to study for this utility.

Grafts in myringoplasty: utilizing a silk fibroin scaffold as a novel device.

Chronic perforations of the eardrum or tympanic membrane represent a significant source of morbidity worldwide. Myringoplasty is the operative repair of a perforated tympanic membrane and is a procedure commonly performed by otolaryngologists. Its purpose is to close the tympanic membrane, improve hearing and limit patient susceptibility to middle ear infections. The success rates of the different surgical techniques used to perform a myringoplasty, and the optimal graft materials to achieve complete closure and restore hearing, vary significantly in the literature. A number of autologous tissues, homografts and synthetic materials are described as graft options. With the advent and development of tissue engineering in the last decade, a number of biomaterials have been studied and attempts have been made to mimic biological functions with these materials. Fibroin, a core structural protein in silk from silkworms, has been widely studied with biomedical applications in mind. Several cell types, including keratinocytes, have grown on silk biomaterials, and scaffolds manufactured from silk have successfully been used in wound healing and for tissue engineering purposes. This review focuses on the current available grafts for myringoplasty and their limitations, and examines the biomechanical properties of silk, assessing the potential benefits of a silk fibroin scaffold as a novel device for use as a graft in myringoplasty surgery.