Keum Seok Bae

Neuron-Like Differentiation of Bone Marrow-Derived Mesenchymal Stem Cells

Purpose Mesenchymal stem cells (MSCs) are multipotent and give rise to distinctly differentiated cells from all three germ layers. Neuronal differentiation of MSC has great potential for cellular therapy. We examined whether the cluster of mechanically made, not neurosphere, could be differentiated into neuron-like cells by growth factors, such as epidermal growth factor (EGF), hepatocyte growth factor (HGF), and vascular endothelial growth factor (VEGF). Materials and Methods BMSCs grown confluent were mechanically separated with cell scrapers and masses of separated cells were cultured to form cluster BMSCs. As described here cluster of BMSCs were differentiated into neuron-like cells by EGF, HGF, and VEGF. Differentiated cells were analyzed by means of phase-contrast inverted microscopy, reverse transcriptase-polymerase chain reaction (RT-PCR), immunofluorescence, and immunocytochemistry to identify the expression of neural specific markers. Results For the group with growth factors, the shapes of neuron-like cells was observable a week later, and two weeks later, most cells were similar in shape to neuron-like cells. Particularly, in the group with chemical addition, various shapes of filament structures were seen among the cells. These culture conditions induced MSCs to exhibit a neural cell phenotype, expressing several neuro-glial specific markers. Conclusion bone marrow-derived mesenchymal stem cells (BMSCs) could be easily induced to form clusters using mechanical scraping, not neurospheres, which in turn could differentiate further into neuron-like cells and might open an attractive possibility for clinical cell therapy for neurodegenerative diseases. In the future, we consider that neuron-like cells differentiated from clusters of BMSCs are needed to be compared and analyzed on a physiological and molecular biological level with preexisting neuronal cells, and studies on the possibility of their transplantation and differentiation capability in animal models are further required.

Adipose tissue-derived mesenchymal stem cells cultured at high density express IFN-β and suppress the growth of MCF-7 human breast cancer cells.

Although it has been reported that mesenchymal stem cells (MSCs) suppress tumor growth in vitro and in vivo, little is known about the underlying molecular mechanisms. We found that type I interferon is expressed in adipose tissue-derived stem cells (ASCs) cultured at high density, and ASCs and their conditioned medium (ASC-CM) suppress the growth of MCF-7 cells in vitro. Growth inhibition was amplified by glucose deprivation that resulted from high density culture of ASCs after 3days. The cytotoxic effect of the ASC-CM obtained from high density culture of ASCs was neutralized by anti-IFN-β antibody. STAT1 was phosphorylated in MCF-7 cells treated with ASC-CM, and JAK1/JAK2 inhibitor treatment decreased STAT1 phosphorylation. The cytotoxic effect of ASC-CM was reduced especially by JAK1 inhibitors in MCF-7 cells. Our findings suggest that ASCs cultured at high density express type I interferons, which suppresses tumor growth via STAT1 activation resulting from IFN-β secretion in MCF-7 breast cancer cells.

Bone mineral density and bone turnover markers in patients on long-term suppressive levothyroxine therapy for differentiated thyroid cancer

Purpose Current management for patients with differentiated thyroid cancer includes near total thyroidectomy and radioactive iodine therapy followed by administration of supraphysiological doses of levothyroxine (L-T4). Although hyperthyroidism is a well known risk factor for osteoporosis, the effects of L-T4 treatment on bone mineral density (BMD) in patients with thyroid cancer do not appear to be as significant as with endogenous hyperthyroidism. In this study, we evaluated the impact of long-term suppressive therapy with L-T4 on BMD and bone turn over markers in Korean female patients receiving L-T4 suppressive therapy. Methods We enrolled 94 female subjects (mean age, 50.84 ± 11.43 years) receiving L-T4 after total or near total thyroidectomy and radioactive iodine therapy for thyroid cancer (mean follow-up period, 12.17 ± 4.27 years). The subjects were divided into three groups by thyroid stimulating hormone (TSH) level (group 1 with TSH level ≤0.001 µIU/mL, group 2 with TSH level between 0.001 and 0.17 µIU/mL, group 3 with TSH level >0.17 µIU/mL) and four groups by quartile of free T4 level. L-T4 dosage, BMD (examined by dual-energy x-ray absorptiometry), and bone turnover markers were evaluated according to TSH and free T4 levels. Results No significant decrease was detected in BMD or bone turnover markers according to TSH level or free T4 level. Also, the prevalence of osteoporosis and osteopenia was not different among groups. Conclusion Long-term L-T4 suppressive therapy after thyroid cancer management did not affect bone density or increase the prevalence of osteoporosis even though TSH levels were supraphysiologically suppressed.

Analysis of prognostic factors in patients with multiple recurrences of papillary thyroid carcinoma

PURPOSE Numerous studies in the past have mentioned various factors that influence the recurrence of papillary thyroid carcinoma, including age, tumor size, advanced stage, extrathyroidal extension, and distant metastasis, and attempts have been made to classify the disease into low-risk and high-risk group based on these clinicopathological factors. However, there has been relatively scarce study on patients with multiple recurrent papillary thyroid carcinoma. This study analyzed the risk factors associated with such cases. MATERIALS AND METHODS This study investigated various clinicopathological factors of 416 patients who were diagnosed with papillary thyroid carcinoma and received primary surgery at Yonsei University Wonju College of Medicine, Department of Surgery, from January 1983 to December 2006 and were followed up until October 2010. An investigation of factors associated with patients showing multiple recurrences was made. RESULTS Patients were divided into 3 groups: group 1 (no recurrence, n=380), group 2 (1 recurrence only, n=21), and group 3 (multiple recurrences, n=15). The univariate analysis on risk factors revealed tumor size greater than 2 cm, multifocality, clinical apparent lymph node metastasis to be risk factors associated with multiple recurrences of papillary thyroid carcinoma. A multivariate analysis performed on variables selected from univariate analysis demonstrated no significant risk factor. The 10-year disease-specific survival for 3 different patient groups (group 1, 2, and 3) was 100%, 100%, and 83.1%, respectively, and patients in more clinically advanced group demonstrated poorer prognosis (p<0.001). The 10-year overall survival rate for the 3 patient groups was 93.9%, 100%, and 92%, respectively, and clinically advanced groups tended to show poorer overall survival rate as well (p=0.046). DISCUSSION A more aggressive and extensive surgery, as well as closer follow up, is to be required when operating on patients with tumor size greater than 2 cm, multifocality, clinical apparent lymph node metastasis. The use of imaging modalities, such as ultrasonography and PET-CT scan, may be desirable when monitoring such patients.

Epidemiology of Trauma Patients and Analysis of 268 Mortality Cases: Trends of a Single Center in Korea

Purpose There is an increasing incidence of mortality among trauma patients; therefore, it is important to analyze the trauma epidemiology in order to prevent trauma death. The authors reviewed the trauma epidemiology retrospectively at a regional emergency center of Korea and evaluated the main factors that led to trauma-related deaths. Materials and Methods A total of 17007 trauma patients were registered to the trauma registry of the regional emergency center at Wonju Severance Christian Hospital in Korea from January 2010 to December 2012. Results The mean age of patients was 35.2 years old. The most frequent trauma mechanism was blunt injury (90.8%), as well as slip-and-fall down injury, motor vehicle accidents, and others. Aside from 142 early trauma deaths, a total of 4673 patients were admitted for further treatment. The most common major trauma sites of admitted patients were on the extremities (38.4%), followed by craniocerebral, abdominopelvis, and thorax. With deaths of 126 patients during in-hospital treatment, the overall mortality (142 early and 126 late deaths) was 5.6% for admitted patients. Ages ≥55, injury severity score ≥16, major craniocerebral injury, cardiopulmonary resuscitation at arrival, probability of survival <25% calculated from the trauma and injury severity score were independent predictors of trauma mortality in multivariate analysis. Conclusion The epidemiology of the trauma patients studied was found to be mainly blunt trauma. This finding is similar to previous papers in terms of demographics and mechanism. Trauma patients who have risk factors of mortality require careful management in order to prevent trauma-related deaths.

Retrospective biodosimetry using translocation frequency in a stable cell of occupationally exposed to ionizing radiation

Two cases of hematological malignancies were reported in an industrial radiography company over a year, which were reasonably suspected of being consequences of prolonged exposure to ionizing radiation because of the higher incidence than expected in the general population. We analyzed chromosomal aberrations in the peripheral blood lymphocytes from the other workers who had been working under similar circumstances as the patients in the company. Among the subjects tested, 10 workers who belonged to the highest band were followed up periodically for 1.5 years since the first analysis. The aim of this study was to clarify pertinence of translocation analysis to an industrial set-up where chronic exposure was commonly expected. To be a useful tool for a retrospective biodosimetry, the aberrations need to be persistent for a decade or longer. Therefore we calculated the decline rates and half-lives of frequency for both a reciprocal translocation and a dicentric chromosome and compared them. In this study, while the frequency of reciprocal translocations was maintained at the initial level, dicentric chromosomes were decreased to 46.9% (31.0–76.5) of the initial frequency over the follow-up period. Our results support the long-term stability of reciprocal translocation through the cell cycle and validate the usefulness of translocation analysis as a retrospective biodosimetry for cases of occupational exposure.

Ultrasonographic guideline for thyroid nodules cytology: single institute experience

Purpose The main issue with the current ultrasonography (US) guidelines is the overestimation of malignant and indeterminate nodules as they do not aid in making decisions to treat patients. To overcome this, new US guidelines for thyroid nodules that have been shown to be better correlated with cytologic results have been proposed. We also suggested specific indications for US-guided fine needle aspiration (FNA) using the new US guidelines. Methods Clinical and pathologic data from 925 patients and 1,419 thyroid nodules were retrospectively collected. All subjects underwent US- and US-guided FNA at Department of Surgery, Wonju Christian Hospital, between March 2010 and July 2011. Sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) were calculated for both the current guidelines and the new guidelines. Results The accuracy, sensitivity, specificity, PPV, and NPV for the current guidelines in predicting malignancy were 24.1%, 99.3%, 62.2%, 25.0%, and 99.8%, respectively. The accuracy, sensitivity, specificity, PPV, and NPV for the new guidelines in predicting malignancy were 66.0%, 96.0%, 86.7%, 47.7%, and 99.4%, respectively. Conclusion The use of the new US guidelines allow for a more accurate and specific diagnosis and a better treatment plan than the current guidelines. Additionally, the use of the new FNA guidelines may help prevent unnecessary FNAs and promote cost-effective follow-up for patients.

Hungry bone syndrome after parathyroidectomy of a minimally invasive parathyroid carcinoma

The prognosis of parathyroid carcinoma varies significantly between numerous studies. Therefore, many attempts have been made to grade the degree of parathyroid carcinoma, and recently, classifying parathyroid carcinomas into either minimally invasive or widely invasive carcinoma- similar to follicular carcinoma of the thyroid- has led to a more reliable prediction of the prognosis. Hungry bone syndrome can occur if parathyroidectomy is performed due to primary hyperparathyroidism regardless of the cause of the disease. Hungry bone syndrome is characterized by postoperative a hypocalcemic state due to remineralization of various minerals, including calcium, of the bone; this syndrome requires a long-term supplementation of calcium. The authors aim to report, along with a review of related literatures, 1 case of a 29-year-old female patient diagnosed with minimally invasive parathyroid carcinoma who fell into hungry bone syndrome after parathyroidectomy.

NF‐κB‐dependency and consequent regulation of IL‐8 in echinomycin‐induced apoptosis of HT‐29 colon cancer cells

The present study was to see whether echinomycin‐induced apoptosis would be NF‐κB‐dependent and if so, whether echinomycin would activate or inhibit NF‐κB as well as resultant chemokine IL‐8 expression. In HT‐29 cells echinomycin activated NF‐κB in time‐dependent manner. EMSA in the presence of antibodies specific for p50 and p65 subunits indicated that echinomycin‐induces the translocation of p50–p65 heterodimeric subunits of NF‐κB. Levels of IκB were detected at initial echinomycin treatment and thereafter decreased, faintly seen after a 6 h treatment. In contrast p‐IκB levels were clearly detected throughout 6–24 h of echinomycin treatment, albeit initially fainted. To clarify the role of NF‐κB on IL‐8 expression in echinomycin‐mediated apoptosis of HT‐29 cells, ELISA plus RT‐PCR clearly showed that IL‐8 production is inducible by echinomycin treatment. Using a specific inhibitor, IL‐8 regulation at echinomycin treatment in HT‐29 cells occurred via both caspase‐3 and NF‐κB‐dependent signal pathway. To confirm whether two different pathways (NF‐κB and caspase) would be coupled, only NF‐κB inhibitor (PDTC) and caspase‐3 specific inhibitor (Z‐DEVD‐FMK) together significantly attenuated echinomycin‐initiated apoptosis of HT‐29 cells, pretreatment of HT‐29 cells with PDTC rarely affected echinomycin‐induced caspase‐3 activation. So echinomycin‐induced apoptosis in HT‐29 cells occurs via NF‐κB activation independent of caspase‐3 activation modulating the resultant‐linked key chemokine IL‐8 expression and echinomycin‐induced apoptosis is NF‐κB‐dependant and directly related to NF‐κB activation, consequently regulating IL‐8 expression.

Efficacy and toxicity of high-dose nebulized colistin for critically ill surgical patients with ventilator-associated pneumonia caused by multidrug-resistant Acinetobacter baumannii☆

Purpose Few studies have compared nebulized and intravenous (IV) colistin for multidrug‐resistant Acinetobacter baumannii and Pseudomonas aeruginosa pneumonia. This study compared the nephrotoxicity and clinical outcomes for these two delivery routes. Methods This study retrospectively compared 95 critically ill surgical patients who were diagnosed with Acinetobacter baumannii ventilator associated pneumonia and received colistin between March 2013 and January 2016. Results The most common diagnoses were brain hemorrhage (27.4%), traumatic brain injury (20%), traumatic thoracic injury (15.8%), and secondary peritonitis (11.6%). Compared to the IV group, the nebulizer group was significantly older (60.0 vs. 67.5 years, p = 0.010), had higher APACHE II scores (16.3 vs. 19.9, p = 0.001), and more frequently had diabetes mellitus (6.8% vs. 21.6%, p = 0.043). Nephrotoxicity was more common in the IV group (60.5% vs. 15.7%, p < 0.0001). Both groups had similar microbiological and clinical outcomes (p = 0.921 and p = 0.719, respectively). Patients with nephrotoxicity exhibited prolonged IV or nebulized colistin treatment and more frequent combination with vancomycin. Nephrotoxicity was independently associated with IV delivery (odds ratio: 8.48, 95% confidence interval: 2.95–24.39, p < 0.0001). Conclusions Nebulized colistin may have less nephrotoxicity and provide similar clinical results, compared to IV colistin. HighlightsColistin can be used intravenously or as a nebulized mist for treating VAP.This study compared the toxicity and clinical outcomes of these two routes.IV colistin was an independent and significant risk factor for nephrotoxicity.Nebulized and IV colistin provided similar clinical and microbiological outcomes.Nebulized colistin may be useful for treating critically ill surgical patients.