Hae Sang Park

Tonsil-derived mesenchymal stromal cells: evaluation of biologic, immunologic and genetic factors for successful banking

BACKGROUND AIMS Although mesenchymal stromal cells (MSC) from human palatine tonsils (tonsillar MSC, T-MSC) have been isolated, whether T-MSC isolated from multiple donors are feasible for cell banking has not been studied. METHODS T-MSC before and after a standard protocol of cryopreservation and thawing were assessed regarding several basic characteristics, including colony-forming unit-fibroblast features, MSC-specific surface antigen profiles, and inhibition of alloreactive T-cell proliferation. In vitro mesodermal differentiation potentials to adipocytes, osteocytes and chondrocytes were detected by staining with either cell-specific dyes or antibody after incubation with each appropriate differentiation medium. Expression of mesoderm-specific genes was also quantified by real-time polymerase chain reaction (PCR) assay. Expression profiles of endoderm-specific genes were identified by reverse transcription PCR assay. The feasibility of T-MSC in future engraftment was tested by short tandem repeat (STR) analysis using genomic DNA isolated randomly from three independent subjects. RESULTS Both fresh and cryopreserved-thawed T-MSC showed a similar high proliferation capacity and expressed primitive cell-surface markers. Hematopoietic cell markers, HLA-DR, co-stimulatory molecules and follicular dendritic cell markers were not detected. In addition to mesodermal differentiation, fresh and cryopreserved-thawed cells also underwent endodermal differentiation, as evidenced by the expression of endoderm-specific genes including forkhead box A2 (FoxA2), SIX homeobox 1 (Six1) and chemokine (C-C motif) ligand 21 (CCL21). Both cells significantly decreased phorbol 12- myristate 13-acetate (PMA)-induced T-cell proliferation. T-MSC from three independent donors formed chimerism in STR analysis. CONCLUSIONS Our results demonstrate for the first time that T-MSC are a potentially good source for MSC banking.

Materials of Acoustic Analysis: Sustained Vowel Versus Sentence

OBJECTIVES Sustained vowel is a widely used material of acoustic analysis. However, vowel phonation does not sufficiently demonstrate sentence-based real-life phonation, and biases may occur depending on the test subjects intent during pronunciation. The purpose of this study was to investigate the differences between the results of acoustic analysis using each material. STUDY DESIGN An individual prospective study. MATERIALS AND METHODS Two hundred two individuals (87 men and 115 women) with normal findings in videostroboscopy were enrolled. Acoustic analysis was done using the speech pattern element acquisition and display program. Fundamental frequency (Fx), amplitude (Ax), contact quotient (Qx), jitter, and shimmer were measured with sustained vowel-based acoustic analysis. Average fundamental frequency (FxM), average amplitude (AxM), average contact quotient (QxM), Fx perturbation (CFx), and amplitude perturbation (CAx) were measured with sentence-based acoustic analysis. Corresponding data of the two methods were compared with each other. SPSS (Statistical Package for the Social Sciences, Version 12.0; SPSS, Inc., Chicago, IL) software was used for statistical analysis. RESULTS FxM was higher than Fx in men (Fx, 124.45 Hz; FxM, 133.09 Hz; P=0.000). In women, FxM seemed to be lower than Fx, but the results were not statistically significant (Fx, 210.58 Hz; FxM, 208.34 Hz; P=0.065). There was no statistical significance between Ax and AxM in both the groups. QxM was higher than Qx in men and women. Jitter was lower in men, but CFx was lower in women. Both Shimmer and CAx were higher in men. CONCLUSIONS Sustained vowel phonation could not be a complete substitute for real-time phonation in acoustic analysis. Characteristics of acoustic materials should be considered when choosing the material for acoustic analysis and interpreting the results.

Voice Change in End-Stage Renal Disease Patients After Hemodialysis: Correlation of Subjective Hoarseness and Objective Acoustic Parameters

INTRODUCTION Patients with end-stage renal disease (ESRD) who are treated with hemodialysis (HD) frequently complain about hoarseness after completion of each HD session. The HD treatment affects laryngeal volume and muscle function. This study attempted to evaluate the vocal effect of HD by acoustic and aerodynamic analysis and to determine the difference between voice change group (VCG) and nonvoice change group (NVCG). MATERIALS AND METHODS A total of 55 patients (34 females and 21 males) diagnosed with ESRD and undergoing outpatient HD were enrolled. The subjects were divided into the VCG (n=13) and NVCG (n=42) by the change of the Korean Voice Handicap Index score. Patients underwent weighing and acoustic, aerodynamic analysis before and after the HD. Fundamental frequency (F0), jitter, shimmer, noise-to-harmonics ratio (NHR), pitch range, habitual pitch, voice energy, and maximal phonation time (MPT) were obtained. The pre- and post-HD data were compared using paired t test. The results were compared after dividing the total group into the VCG and NVCG categories. Correlation between the change of the weight and change of the voice analysis result was certified by Pearson correlation coefficient. RESULTS The F0 and habitual pitch increased in all subjects. The NHR and MPT parameters significantly decreased (P<0.05). In the NVCG group, all the results were same as the total group. In the VCG group, the NHR result differed from the total group. All acoustic parameters showed no statistically significant differences between the two groups. There was no correlation between the weight change (%) and the change of acoustic parameter results. CONCLUSIONS The NVCG group of patient displayed improvement in NHR, whereas the VCG group showed no change. Weight change did not significantly correlate with the voice analysis results.

Intraoral removal of stones in the proximal submandibular duct: Usefulness of a surgical landmark for the hilum†

INTRODUCTION Sialolithiasis is the most common cause of salivary gland disease and about 80% to 90% of stones occur in the submandibular gland (SMG). Among them, 40% of the SMG stones are located in the distal submandibular duct near the punctum, and they are removed through the intraoral approach. The other 60% of the SMG stones are located in the proximal submandibular duct or in the submandibular gland, and they usually are removed by transcervical SMG resection. However, transcervical SMG resection has several disadvantages; hence, minimally invasive techniques are becoming increasingly important. The minimally invasive techniques include extracorporeal shockwave lithotripsy (ESWL), radiologically or endoscopically guided basket retrieval, and intraoral stone removal. In particular, intraoral stone removal has advantages, including patient tolerability and acceptance, a less time-consuming procedure, and the ability to be performed under both local and general anesthesia. However, intraoral stone removal has several disadvantages, including the risk of lingual nerve injury; a poor surgical field; and technical difficulty in approaching the hilar area, especially during the removal of larger and proximal submandibular stones. The purpose of this study was to identify a surgical landmark for a convenient approach to the proximal submandibular duct and hilar area of the SMG, and to evaluate the safety and effectiveness of the intraoral removal of stones in the proximal SMG. MATERIALS AND METHODS

Standardization of A Physiologic Hypoparathyroidism Animal Model

Ideal hypoparathyroidism animal models are a prerequisite to developing new treatment modalities for this disorder. The purpose of this study was to evaluate the feasibility of a model whereby rats were parathyroidectomized (PTX) using a fluorescent-identification method and the ideal calcium content of the diet was determined. Thirty male rats were divided into surgical sham (SHAM, n = 5) and PTX plus 0, 0.5, and 2% calcium diet groups (PTX-FC (n = 5), PTX-NC (n = 10), and PTX-HC (n = 10), respectively). Serum parathyroid hormone levels decreased to non-detectable levels in all PTX groups. All animals in the PTX—FC group died within 4 days after the operation. All animals survived when supplied calcium in the diet. However, serum calcium levels were higher in the PTX-HC than the SHAM group. The PTX-NC group demonstrated the most representative modeling of primary hypothyroidism. Serum calcium levels decreased and phosphorus levels increased, and bone volume was increased. All animals survived without further treatment and did not show nephrotoxicity including calcium deposits. These findings demonstrate that PTX animal models produced by using the fluorescent-identification method, and fed a 0.5% calcium diet, are appropriate for hypoparathyroidism treatment studies.