Use of Magnetic Resonance Imaging to Assess the Regenerative Effects of Adipose Tissue-Derived Mesenchymal Stem Cells in a Rabbit Cartilaginous Laryngeal Defect Model.

Background: Stenosis and scar formation after repair of laryngeal tissue defects are serious problems that can significantly influence a patient's quality of life. Objective: In this study, we evaluated the use of magnetic resonance imaging to assess the efficacy of adipose tissue-derived mesenchymal stem cells (ASCs) on cartilaginous regeneration in an experimental rabbit model. Methods: Ten male white Dutch rabbits each had a 5 mm cartilaginous defect created surgically in the right and left thyroid lamina. On the right side, ASCs labeled with iron oxide particles were infused. As a control, the left side was left untreated. Repair of the defects were then evaluated by direct observation, histological evaluation, and magnetic resonance imaging monitoring done on days 1, 7, 14, and 28. Results: Histological examination revealed that compared with control, transplanted ASCs significantly increased cartilage regeneration (P ˂ 0.001), reduced inflammation (P ˂ 0.001), and fibrosis (P = 0.050). Magnetic resonance imaging tracking showed accurate placement and viability of the infused ASCs, as evidenced by low signal intensity onT2 weighted images at the level of the right thyroid cartilage. Conclusions: Infusion of ASCs improved laryngeal regeneration of surgically induced cartilaginous defects while decreasing fibrous tissue formation in this in vivo rabbit model. Furthermore, magnetic resonance imaging was shown to be a useful, noninvasive method to track correct ASCs placement and viability in cartilage regeneration in this animal model.

The Healing Effect of Amniotic Membrane in Laryngeal Defects in Rabbit Model.

OBJECTIVE: Fibrosis and scar formation following laryngeal repairing is a major concern. This study evaluated the efficacy of applying amniotic membrane (AM) as a biologic dressing to reduce fibrosis and inflammation and promote cartilage repair. STUDY DESIGN: Experimental animal study. METHODS: Nine male white Dutch rabbits were selected. A standard defect (5 mm) was created in right and left thyroid lamina. In the right side, two layers of AM were applied while the left side was kept intact for future comparison. Histologic examination with criteria of inflammation, fibrosis, and cartilage regeneration was performed 2, 4, and 6 weeks following AM application. All procedures were done according to animal ethics rules. RESULTS: Histologic and gross examination showed that AM application was able to reduce inflammation and fibrosis and improve cartilage regeneration significantly. CONCLUSION: As a useful intervention, AM application can reduce inflammation and fibrosis and enhance cartilage regeneration, following laryngeal defect repair. LEVEL OF EVIDENCE: NA Laryngoscope, 131:E527-E533, 2021.

Successful Surgical Separation of Thoraco-Omphalopagus Symmetrical Conjoined Twins in Iran: Two Case Reports.

Conjoined twins are derived from the division of a single fertilized ovum; a phenomenon accompanied with multiple congenital anomalies. Such twins are identical, of the same sex, and more likely to be female. Most twins die during the embryonic period, and only 18% survive longer than 24 hours. There are complex anomalies in thoraco-omphalopagus twins that makes them unlikely to live long enough to undergo separation. Treatment of this uncommon condition presents both surgical and anesthetic challenges. The management of rare anomalies is difficult even for skilled surgeons. Therefore, it is logical to use the knowledge gained from previous experiences. We herein present the first successful surgical separation of two pairs of thoraco-omphalopagus conjoined twins at the Pediatric Surgery Center of Namazi Hospital (Shiraz, Iran). In both cases, the neonates had separate hearts and common pericardium. Contrast-enhanced computed tomography of two sets of twins showed fusion of sternum, pericardium, diaphragm, and left lobe of liver. Critical steps of the surgical separation were identified and contingency plans were made for possible partial liver donation and cross-circulation between twins. The separation procedure and reconstruction of the abdominal wall were successfully performed. Both pairs of twins, now 6- and 8-year-old, are healthy and have normal growth and are under follow-up.

Liver Transplant for Children With Hepatocellular Carcinoma and Hereditary Tyrosinemia Type 1.

OBJECTIVES: This study sought to determine the prevalence of hepatocellular carcinoma and other premalignant lesions in children with hereditary tyrosinemia type 1 who had undergone an orthotopic liver transplant at the Shiraz Transplant Center, in Shiraz, Iran. MATERIALS AND METHODS: Between September 2006, and June 2011, thirty-six patients with hereditary tyrosinemia type 1 received a liver transplant from a deceased (whole or split) or a living-related donor. Clinical records and pathologic specimens, before and after surgery, for each case were reviewed. In addition, ultrasound, abdominal computed tomographic imaging scan findings, and levels of alpha-fetoprotein were recorded. RESULTS: Twenty-two patients with hepatic nodules larger than 10 mm underwent a Tru-Cut needle biopsy before their liver transplant. In 2 patients, a diagnosis of hepatocellular carcinoma was made by pathologic examination; in the other 20, cirrhosis was confirmed with no evidence of malignancy. After pathologic examination of the explanted livers, the largest nodules in the 36 patients were 35 mm. Five cases had at least 1 nodule of hepatocellular carcinoma. Three of the other patients had small cell dysplasia in some of nodules. All 5 cases with hepatocellular carcinoma were patients older than 2 years of age (19 patients were older than 2 years of age). All patients with hepatocellular carcinoma received pretransplant nitisinone treatment. All patients with hepatocellular carcinoma after their liver transplant are alive at the time of this writing. CONCLUSIONS: The prevalence of cell dysplasia and hepatocellular carcinoma in children with hereditary tyrosinemia type 1 in our study is not as high as that reported previously, so it appears that patients older than 2 years of age require a liver transplant.