Biomedical subjects

Behrooz A Torkian

Publications and source records attributed to Behrooz A Torkian.

3 recordsLinked to original sources

PubMed2006

Noninvasive measurement of ablation crater size and thermal injury after CO2 laser in the vocal cord with optical coherence tomography.

OBJECTIVE: To characterize tissue destruction after CO(2) laser-ablation of the vocal cords with the use of optical coherence tomography (OCT). STUDY DESIGN AND SETTING: OCT was used to image fresh porcine vocal cords after laser ablation. OCT and histology estimates of the ablation crater dimensions and the depth of thermal injury were obtained. RESULTS: The vocal cord substructures up to 2.29 mm in depth at 10 microm resolution, and the thermal disruption after laser ablation were identified by OCT. OCT and histology estimates of the lesion dimensions showed no significant differences. Crater depth is directly proportional to laser power, whereas crater width and the zone of thermal injury appear to be unrelated to laser power. CONCLUSIONS: OCT may be used to accurately characterize the native states and the laser-induced thermal injury of laryngeal mucosa, within the inherent limitation in its depth of penetration. OCT may be a useful diagnostic and monitoring tool in an otolaryngology practice.

Animals↗

PubMed2004

Granulomatous inflammation and nerve necrosis in a case of apparent idiopathic vocal fold paralysis: report of a case.

OBJECTIVES: We will present clinical and pathologic findings of the recurrent laryngeal nerve of a 54-year-old man with apparent idiopathic vocal fold paralysis and discuss clinical and scientific implications of these findings. STUDY DESIGN: Our design is in the format of a case report with emphasis on the clinical, intraoperative, histologic, and neuropathologic findings, followed by a discussion of contemporary theories of idiopathic unilateral vocal fold immobility and the implications of our findings. METHODS: A 54-year-old man presented with a 2-year history of unilateral vocal fold motion impairment (VFMI) after an upper respiratory infection. Radiographic and laboratory data revealed no organic cause. The patient clinically appeared to have a classical unilateral vocal fold paralysis and had previously undergone collagen injection and medialization thyroplasty, each with only temporary improvement of voice. We performed ansa cervicalis-recurrent laryngeal nerve anastomosis. RESULTS: Intraoperative dissection revealed an indurated and thickened section of nerve approximately 15 mm in length, located at the beginning of the intralaryngeal segment, near the cricothyroid joint. Segments of this nerve were submitted for histologic evaluation, revealing necrosis with granulomatous inflammation. Postoperative electromyography and videostrobolaryngoscopy were consistent with successful reinnervation from the ansa procedure. CONCLUSIONS: The diagnosis of "idiopathic VFMI" likely represents a number of distinct pathologic entities. This case highlights our lack of understanding of idiopathic VFMI and raises many important questions regarding our current theories of this diagnosis. The clinical and pathologic implications are discussed, and continued investigation is recommended.

Anastomosis, Surgical↗

PubMedDate not supplied

Modeling aberrant wound healing using tissue-engineered skin constructs and multiphoton microscopy.

BACKGROUND: Keloids and hypertrophic scars result from aberrant wound healing and remain a potential complication of any surgical procedure or trauma. Investigation of aberrant wound healing has been limited to the study of growth factors, collagen precursors, and DNA synthesis in simple in vitro systems, which necessitate removal or destruction of cells or factors in the growth environment of cell cultures. Multiphoton microscopy (MPM) can use endogenous chromophores such as collagen and nicotinamide adenine dinucleotide hydrogenase to produce thin optical sections of thick living tissues without the use of dyes or stains. Endogenous second-harmonic-generation (SHG) signals in collagen can be collected to form an MPM image. OBJECTIVE: To present a novel wound-healing model used to investigate keloid-derived fibroblast activity and collagen production in the same intact tissue-engineered construct over time. METHODS: Artificial tissue constructs called RAFTs (produced by suspension of keloid or normal dermal fibroblasts in type I collagen gel with an overlying keratinocyte layer) were cultured at air-fluid interface. Multiphoton microscopy SHG images of collagen in the intact tissue constructs consisting of normal or keloid-derived fibroblasts were obtained. The constructs were then incised with a scalpel. Serial MPM and phase-contrast microscopy images were obtained to monitor changes in the extracellular matrix in response to wounding of the artificial skin construct over 8 days. RESULTS: The tissue-engineered constructs formed a bilayer resembling the dermis and epidermis of human skin. Phase-contrast microscopy revealed migration of keratinocytes into the defect created by scalpel wounding. The constructs were found to contract with time after wounding. The MPM SHG images showed collagen deposition in the tissue constructs after wounding. Tissue constructs with keloid-derived fibroblasts were found to deposit collagen at a higher rate than those with normal fibroblasts. CONCLUSIONS: The MPM model described herein permits serial observation of the same intact specimens without the need for fixation or cytotoxic stains. Furthermore, it demonstrates the biologic activity of RAFT artificial tissue constructs.

Cells, Cultured↗