Larynx preservation surgery in pyriform sinus cancer

As a general rule, surgery, whenever possible followed by irradiation, is considered to be a standard treatment for pyriform sinus cancer. In early primary lesions, many different approaches have been tried for larynx preservation. From 1990-1997, 7 patients with pyriform sinus carcinoma without the involvement of pyriform sinus apex were treated with partial laryngopharyngectomy at the Asan Medical Center. Three patients were T1 stage and four were T2. All patients had nodal metastases and were treated with neck dissection and postoperative radiotherapy. Follow-up period was 1-8 years. One regional recurrence and one distant metastasis occurred; however, there was no recurrence at the primary site. The voices of all the patients were saved. The most uncomfortable postoperative symptom was mild aspiration. From these results, we can conclude that partial laryngopharyngectomy with neck dissection might be the favorable treatment modality for selected cases of pyriform sinus cancer.     

Tissue‐Engineered Tracheal Reconstruction Using Three‐Dimensionally Printed Artificial Tracheal Graft: Preliminary Report

Three‐dimensional printing has come into the spotlight in the realm of tissue engineering. We intended to evaluate the plausibility of 3D‐printed (3DP) scaffold coated with mesenchymal stem cells (MSCs) seeded in fibrin for the repair of partial tracheal defects. MSCs from rabbit bone marrow were expanded and cultured. A half‐pipe‐shaped 3DP polycaprolactone scaffold was coated with the MSCs seeded in fibrin. The half‐pipe tracheal graft was implanted on a 10 × 10‐mm artificial tracheal defect in four rabbits. Four and eight weeks after the operation, the reconstructed sites were evaluated bronchoscopically, radiologically, histologically, and functionally. None of the four rabbits showed any sign of respiratory distress. Endoscopic examination and computed tomography showed successful reconstruction of trachea without any collapse or blockage. The replaced tracheas were completely covered with regenerated respiratory mucosa. Histologic analysis showed that the implanted 3DP tracheal grafts were successfully integrated with the adjacent trachea without disruption or granulation tissue formation. Neo‐cartilage formation inside the implanted graft was sufficient to maintain the patency of the reconstructed trachea. Scanning electron microscope examination confirmed the regeneration of the cilia, and beating frequency of regenerated cilia was not different from those of the normal adjacent mucosa. The shape and function of reconstructed trachea using 3DP scaffold coated with MSCs seeded in fibrin were restored successfully without any graft rejection.     

Response to pretransplant hypomethylating agents influences the outcome of allogeneic hematopoietic stem cell transplantation in adults with myelodysplastic syndromes

This study describes a retrospective analysis on the transplant outcome of 56 consecutive patients with myelodysplastic syndrome (MDS) according to their response to hypomethylating agents (HMA). While 2‐yr disease‐free survival (DFS) of patients who transformed to acute myeloid leukemia (n = 12) was 25%, that of the remaining patients with MDS according to response to HMA was 73.1%, 68.1%, 50.0%, and 20.8% in G‐COR (group of continuous response, n = 19), G‐NoC (group of no change, n = 15), G‐LOR (group of loss of response, n = 6), and G‐DP (group of disease progression, n = 4), respectively. When dichotomized as G‐COR/G‐NoC versus G‐LOR/G‐DP, significantly different 2‐yr DFS (71.0% vs. 33.3%; P = 0.004) and relapse (14.1% vs. 46.7%; P = 0.016) were demonstrated. On multivariate analysis, G‐LOR/G‐DP [hazard ratio (HR), 3.91; P = 0.008] and poor karyotype at transplantation (HR, 2.69; P = 0.017) were the significant predictors for poor DFS, as G‐LOR/G‐DP was for relapse (HR, 6.28; P = 0.011). DFS was significantly poor in patients with any of the two predictors in all MDS (81.5% vs. 34.9%; P = 0.001) or higher‐risk MDS (HrMDS) at the time of HMA (80.7% vs. 29.2%; P = 0.005). G‐COR showed a trend of better DFS compared with G‐NoC among HrMDS (74.6% vs. 36.5%; P = 0.090). These results implicate the significance of response to HMA on hematopoietic stem cell transplantation (HSCT) outcomes and support the need for future study to verify the suggested strategy of proceeding to transplantation before LOR or DP, especially for HrMDS.     

A Case of Nonalcoholic Steatohepatitis and Small Intestinal Bacterial Overgrowth with Peripheral Edema Caused by Intestinal Bypass Surgery and Relieved by Repair

Intestinal bypass surgery, particularly jejuno-ileal bypass surgery, performed for the purpose of weight reduction may cause an unexpected exacerbation of nonalcoholic steatohepatitis (NASH). Here, we report a case of NASH caused by small intestinal bacterial overgrowth, which developed after jejuno-colic bypass surgery and resolved dramatically after surgical correction.     

Effect of PRX-1 Downregulation in the Type 1 Diabetes Microenvironment

Type 1 diabetes (T1D) is caused by dysregulation of the immune system in the pancreatic islets, which eventually leads to insulin-producing pancreatic β-cell death and destabilization of glucose homeostasis. One of the major characteristics of T1D pathogenesis is the production of inflammatory mediators by macrophages that result in destruction or damage of pancreatic β-cells. In this study the inflammatory microenvironment of T1D was simulated with RAW264.7 cells and MIN6 cells, acting as macrophages and pancreatic β-cells respectably. In this setting, peroxiredoxin-1, an anti-oxidant enzyme was knocked down to observe its functions in the pathogenesis of T1D. RAW264.7 cells were primed with lipopolysaccharide and co-cultured with MIN6 cells while PRX-1 was knocked down in one or both cell types. Our results suggest that hindrance of PRX-1 activity or the deficiency of this enzyme in inflammatory conditions negatively affects pancreatic β-cell survival. The observed decrease in viability of MIN6 cells seems to be caused by nitric oxide production. Additionally, it seems that PRX-1 affects previously reported protective activity of IL-6 in pancreatic β cells as well. These results signify new, undiscovered roles for PRX-1 in inflammatory conditions and may contribute toward our understanding of autoimmunity.     

Study of cobalt doping control via various routes in thoroughbred horses

Cobalt is a substance that has been abused for athletic performance enhancement and has thus been prohibited by human and animal sports doping control authorities. However, because cobalt is present in humans and animals as a trace element, a certain level of cobalt is naturally present in their excretions. In the racing industry, cobalt is a controlled substance with a threshold concentration specified by the International Agreement on Breeding, Racing and Wagering (IABRW) for international harmonization. Due to environmental and feed consumption differences among countries, regional cobalt concentration trends should be evaluated before cobalt testing is introduced. In this study, we conducted a preliminary evaluation of the urinary concentration of cobalt among a population of racehorses in Korea using inductively coupled plasma mass spectrometry (ICP-MS) analysis, followed by analysis of the urinary release of cobalt after the administration of cobalt chloride in various situations. The normal distribution for the Korea-based racehorses was used to determine a urine concentration limit (96.5 ng/ml, risk factor of 1 in 10,000). After the intravenous (IV) administration of CoCl₂, the initial elimination of cobalt was rapid. A high concentration (over 2,000 ng/ml) and a slow excretion pattern were observed during the final 2 weeks of the 3-week observation period. When CoCl₂ was administered orally, maximum concentration (C_max, 92–992 ng/ml) was observed at 6–8 h.