Normative electromyography data and influencing factors in intraoperative neuromonitoring using adhesive skin electrodes during thyroid surgery

Background

Skin electrodes have been reported to be a useful alternative recording method for intraoperative neuromonitoring (IONM) and show typical electromyography (EMG) waveforms while overcoming the shortcomings of the EMG endotracheal tube. However, the skin electrodes showed relatively lower evoked amplitudes than other recording methods. In this study, we analyzed normative EMG data using skin electrodes and factors that affect the evoked amplitude of thyroid IONM.

Methods

In total, 167 patients [242 nerves at risk (NAR)] who underwent thyroidectomy under IONM with adhesive skin electrodes were analyzed. A pair of skin electrodes was attached to the lateral border of the lamina of the thyroid cartilage. Evoked EMG data, including mean amplitude and latency, obtained after stimulation of the recurrent laryngeal nerve (RLN) and vagus nerve (VN), were collected and analyzed.

Results

The mean amplitudes of RLN and VN recorded via skin electrodes were 255.48±96.53 and 236.15±69.72 μV, respectively. The mean latency of the right and left RLN was 3.22±0.03 and 3.49±0.08 mS, respectively. The mean latency of the right and left VN was 5.37±0.80 and 7.57±0.10 mS, respectively. The mean amplitude was significantly lower in the obesity, male, and total thyroidectomy (TT) groups. As body mass index (BMI) and age increased, the amplitude of EMG tended to decrease significantly.

Conclusions

The evoked amplitude recorded with the skin electrodes was relatively low. A larger surgical extent, obesity, male sex, and age >55 years showed significantly lower evoked amplitudes.

Evaluation of Vertical Level Differences Between Left and Right Vocal Folds Using Artificial Intelligence System in Excised Canine Larynx

OBJECTIVES

This study aimed to establish an artificial intelligence (AI) system to classify vertical level differences between vocal folds during vocalization and to evaluate the accuracy of the classification.

METHODS

We designed models with different depths between the right and left vocal folds using an excised canine larynx. Video files for the data set were obtained using a high-speed camera system and a color complementary metal oxide semiconductor camera with global shutter. The data sets were divided into training, validation, and testing. We used 20,000 images for building the model and 8000 images for testing. To perform deep learning multiclass classification and to estimate the vertical level difference, we introduced DenseNet121-ConvLSTM.

RESULTS

The model was trained several times using different numbers of epochs. We achieved the most optimal results at 100 epochs, and the batch size used during training was 16. The proposed DenseNet121-ConvLSTM model achieved classification accuracies of 99.5% and 88.0% for training and testing, respectively. After verification using an external data set, the overall accuracy, precision, recall, and f1-score were 90.8%, 91.6%, 90.9%, and 91.2%, respectively.

CONCLUSIONS

The newly developed AI system may be an easy and accurate method for classifying superior and inferior vertical level differences between vocal folds. Thus, this AI system can be applied and may help in the assessment of vertical level differences in patients with unilateral vocal fold paralysis.

Proliferation-Related Features of the Human Mesenchymal Stem Cells Derived from Palatine Tonsils, Adipose Tissues, and Bone Marrow

BACKGROUND

Mesenchymal stem cells (MSCs) are widely used in regenerative medicine and cell-based transplantations. However, an in-depth comparison of the different MSC origins is lacking. This study aimed to compare the expression of adipose-derived (AMSCs), bone marrow-derived (BMSCs), and tonsil-derived (TMSCs) and evaluate whether TMSCs are good alternatives for AMSCs or BMSCs.

METHODS

We analyzed the expression levels of 47,000 transcripts in AMSCs (n = 4), BMSCs (n = 4), and TMSCs (n = 4) using GeneChip. Microarray data were analyzed using the LIMMA package to compare the TMSCs, AMSCs, and BMSCs. Hub genes were analyzed using STRING and Cytoscape. To ascertain the functional roles of AURKA and AURKB, small interfering RNA (siRNA) molecules specifically targeting AURKA and AURKB mRNA were synthesized and employed to induce knockdown of AURKA and AURKB in TMSC and AMSC. We analyzed the expression level of OCT4, SOX-2, and NANOG genes in TMSC and AMSCs by cell culture and real-time PCR.

RESULTS

We identified commonly increased 256 and decreased 160 genes in TMSCs from the differentially expressed genes (DEGs) between the TMSCs, AMSCs, and BMSCs. In the DEG-based protein-protein interaction and gene set enrichment analysis, hub genes (AURKA, AURKB, CDC20, and BUB1) highly expressed in TMSCs were enriched for development- and progression-related oocyte meiosis, the cell cycle, and ubiquitin-mediated proteolysis. In vitro analysis demonstrated that cells with downregulated expression of AURKA and AURKB exhibited a significant reduction in proliferation compared to control cells. However, silencing of the genes did not affect the differentiation capacity in TMSCs and AMSCs.

CONCLUSION

Our study compared MSCs of different origins to better understand the similarities and differences among these cell types.

Efficacy of Tegoprazan in Patients with Laryngopharyngeal Reflux Disease: A Preliminary Feasibility Study

Tegoprazan is a novel, potent, and highly selective potassium-competitive acid blocker that inhibits gastric acid secretion with rapid onset of action and prolonged control of gastric acidity. We performed a preliminary feasibility study to evaluate whether tegoprazan could control symptoms more effectively than a placebo in patients with laryngopharyngeal reflux disease (LPRD). In this double-blind, randomized, placebo-controlled trial, 35 patients with LPRD were randomly assigned to two groups: tegoprazan 50 mg daily and placebo. The primary endpoint was the complete resolution rate of LPRD symptoms after 8 weeks of medication, and the secondary endpoints were the complete resolution rate of LPRD symptoms after 4 weeks of medication and changes in the reflux symptom index (RSI) and reflux finding score (RFS) from baseline at 4 and 8 weeks of medication. There was no difference in the complete symptom resolution rates at 8 weeks between the tegoprazan and placebo groups (29.4% [5/17] vs. 27.8% [5/18], p = 1.000). Moreover, there was no significant difference in the complete symptom resolution rates at 4 weeks between the two groups. Compared with the baseline, both tegoprazan and placebo significantly reduced the total RSI and RFS scores after 4 and 8 weeks of medication; however, tegoprazan was not superior to the placebo. In conclusion, tegoprazan (50 mg daily) administration improved LPRD symptoms and signs. However, tegoprazan did not show superiority over placebo. Considering the potential effectiveness of tegoprazan as an acid-suppressing therapy and the possibility of type II error due to a low number of included patients herein, prospective, large-scale, multi-center studies with a higher dose of tegoprazan for a prolonged duration are required to elucidate the efficacy of tegoprazan in patients with LPRD. (ClinicalTrials.gov: NCT05871398).

Effect of deferoxamine and ferrostatin-1 on salivary gland dysfunction in ovariectomized rats

The mechanism underlying xerostomia after menopause has not yet been fully elucidated. This study aimed to investigate the mechanism of xerostomia and the effect of the ferroptosis inhibitors deferoxamine (DFO) and ferrostatin-1 (FER) on salivary gland dysfunction in a postmenopausal animal model. Twenty-four female Sprague-Dawley rats were randomly divided into four groups: a SHAM group (n = 6, sham-operated rats), an OVX group (n = 6, ovariectomized rats), an FER group (n = 6, ovariectomized rats injected intraperitoneally with FER), and a DFO group (n = 6, ovariectomized rats injected intraperitoneally with DFO). GPX4 activity, iron accumulation, lipid peroxidation, inflammation, fibrosis, and salivary gland function were analyzed. Recovery of GPX4 activity and a decrease in iron accumulation and cytosolic MDA + HAE were observed in the DFO group. In addition, collagen I, collagen III, TGF-β, IL-6, TNF-α, and TGF-β levels were decreased in the DFO group compared to the OVX group. Recovery of GPX4 activity and the morphology of mitochondria, and reduction of cytosolic MDA + HAE were also observed in the FER group. In addition, decreased expression of inflammatory cytokines and fibrosis markers and increased expression of AQP5 were observed in both the DFO and FER groups. Postmenopausal salivary gland dysfunction is associated with ferroptosis, and DFO and FER may reverse the postmenopausal salivary gland dysfunction after menopause. DFO and FER are hence considered promising treatments for postmenopausal xerostomia.

Feasibility of facial nerve monitoring using adhesive surface electrodes during parotidectomy: a comparative study with needle electrodes

PURPOSE

Electrophysiological monitoring of the facial nerve during parotidectomy has been reported as an adjunctive method to prevent facial nerve injury. Classically, a needle electrode is used to obtain electromyographic (EMG) signals from facial muscles during facial nerve monitoring (FNM) of parotid surgery, likewise adhesive surface electrodes. This study aimed to investigate the feasibility of performing FNM with surface electrodes during parotid surgery and to compare EMG values with needle electrodes.

METHODS

Thirty patients who underwent parotidectomy under FNM using adhesive surface and needle electrodes were included. Two pairs of adhesive surface electrodes and needle electrodes were used for FNM during parotid surgery. Mean amplitudes were collected after electrical facial nerve stimulation at 1 mA after specimen removal.

RESULTS

The mean amplitude of the adhesive surface electrodes was 226.50 ± 118.44 μV (orbicularis oculi muscle) and 469.6 ± 306.06 μV (orbicularis oris muscle), respectively. The mean amplitude of the needle electrodes was 449.85 ± 248.10 μV (orbicularis oculi muscle) and 654.66 ± 395.71 μV (orbicularis oris muscle), respectively. The mean amplitude of the orbicularis oris muscle was significantly greater than that of the orbicularis oculi. The amplitude values measured in the orbicularis oculi muscle showed significant differences between the needle and skin electrodes.

CONCLUSIONS

Facial nerve monitoring (FNM) using adhesive surface electrodes is feasible in parotid surgery. Although the mean amplitude value of the surface electrode was relatively lower than that of the needle electrode, the surface electrode is considered a feasible and safe EMG recording device for FNM in parotid surgery.

Guideline for the Surgical Management of Locally Invasive Differentiated Thyroid Cancer From the Korean Society of Head and Neck Surgery

The aim of this study was to develop evidence-based recommendations for determining the surgical extent in patients with locally invasive differentiated thyroid cancer (DTC). Locally invasive DTC with gross extrathyroidal extension invading surrounding anatomical structures may lead to several functional deficits and poor oncological outcomes. At present, the optimal extent of surgery in locally invasive DTC remains a matter of debate, and there are no adequate guidelines. On October 8, 2021, four experts searched the PubMed, Embase, and Cochrane Library databases; the identified papers were reviewed by 39 experts in thyroid and head and neck surgery. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used to assess the quality of evidence, and to develop and report recommendations. The strength of a recommendation reflects the confidence of a guideline panel that the desirable effects of an intervention outweigh any undesirable effects, across all patients for whom the recommendation is applicable. After completing the draft guidelines, Delphi questionnaires were completed by members of the Korean Society of Head and Neck Surgery. Twenty-seven evidence-based recommendations were made for several factors, including the preoperative workup; surgical extent of thyroidectomy; surgery for cancer invading the strap muscles, recurrent laryngeal nerve, laryngeal framework, trachea, or esophagus; and surgery for patients with central and lateral cervical lymph node involvement. Evidence-based guidelines were devised to help clinicians make safer and more efficient clinical decisions for the optimal surgical treatment of patients with locally invasive DTC.

Survey of Korean head and neck surgeons and endocrinologists for the surgical extent of 1.5 and 2.5 cm papillary thyroid carcinoma

Background

The surgical extent of 1-4 cm papillary thyroid carcinoma (PTC) is controversial. We aimed to determine the current trend in the extent of thyroidectomy and prophylactic central neck dissection (pCND) for 1.5 and 2.5 cm PTC, which are the most clinically controversial sizes.

Methods

The questionnaire was sent to 342 Korean Society of Head and Neck Surgery and 160 one branch of Korean Endocrine Society members from June to July 2021 by e-mail. A questionnaire included extent of thyroidectomy [hemithyroidectomy (Hemi) vs. total thyroidectomy (TT)] and pCND according to the tumor location and degree of extrathyroidal extension (ETE) at 1.5 or 2.5 cm PTC. We compared the proportion of respondents' preference for each scenario.

Results

Fifty-seven of 342 surgeons and twenty-seven of 160 endocrinologists responded to the questionnaire. At 1.5 and 2.5 cm PTC without ETE, both groups preferred Hemi, and there was no difference between the groups. When 1.5 or 2.5 cm PTC with anterior minimal ETE was suspected, the preference for Hemi by endocrinologists was significantly lower than that by surgeons (P<0.05). When anterior and posterior gross ETE were suspected, TT was preferred in both groups. When anterior gross ETE was suspected, the preference for Hemi by endocrinologists was significantly lower than that by surgeons (P<0.05). There was no difference between the groups in the posterior gross ETE. Surgeons preferred Hemi and endocrinologists preferred TT for a 1.5 cm PTC located in the isthmus. The pCND showed a similar pattern in both groups according to the size and location of the tumor and the degree of ETE. The proportion of Hemi did not differ between high-experience and low-experience endocrinologists. Also, there was no significant difference in preference for surgical extent between low-volume and high-volume surgeons.

Conclusions

TT was frequently preferred in tumors with a large size or gross ETE, and pCND was frequently preferred in cases of suspected gross ETE. This study shows as the extent of thyroid surgery may differ between endocrinologists and surgeons and this could be confusing to patient and affect the patient outcomes. Therefore, multidisciplinary approach considering the extent of surgery for thyroid cancer is recommended.

Diagnosis of Early Glottic Cancer Using Laryngeal Image and Voice Based on Ensemble Learning of Convolutional Neural Network Classifiers

OBJECTIVES

The purpose of study is to improve the classification accuracy by comparing the results obtained by applying decision tree ensemble learning, which is one of the methods to increase the classification accuracy for a relatively small dataset, with the results obtained by the convolutional neural network (CNN) algorithm for the diagnosis of glottal cancer.

METHODS

Pusan National University Hospital (PNUH) dataset were used to establish classifiers and Pusan National University Yangsan Hospital (PNUYH) dataset were used to verify the classifier's performance in the generated model. For the diagnosis of glottic cancer, deep learning-based CNN models were established and classified using laryngeal image and voice data. Classification accuracy was obtained by performing decision tree ensemble learning using probability through CNN classification algorithm. In this process, the classification and regression tree (CART) method was used. Then, we compared the classification accuracy of decision tree ensemble learning with CNN individual classifiers by fusing the laryngeal image with the voice decision tree classifier.

RESULTS

We obtained classification accuracy of 81.03 % and 99.18 % in the established laryngeal image and voice classification models using PNUH training dataset, respectively. However, the classification accuracy of CNN classifiers decreased to 73.88 % in voice and 68.92 % in laryngeal image when using an external dataset of PNUYH. To solve this problem, decision tree ensemble learning of laryngeal image and voice was used, and the classification accuracy was improved by integrating data of laryngeal image and voice of the same person. The classification accuracy was 87.88 % and 89.06 % for the individualized laryngeal image and voice decision tree model respectively, and the fusion of the laryngeal image and voice decision tree results represented a classification accuracy of 95.31 %.

CONCLUSION

The results of our study suggest that decision tree ensemble learning aimed at training multiple classifiers is useful to obtain an increased classification accuracy despite a small dataset. Although a large data amount is essential for AI analysis, when an integrated approach is taken by combining various input data high diagnostic classification accuracy can be expected.

ACE2 and TMPRSS2 Immunolocalization and COVID-19-Related Thyroid Disorder

Thyroid dysfunction has been reported to be an extrapulmonary symptom of COVID-19. It is important to identify the tissue subset that expresses angiotensin-converting enzyme 2 (ACE2) and transmembrane protease serine 2 (TMPRSS2), which are essential for host infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), in order to understand the viral pathogenesis of COVID-19-related thyroid dysfunction. We investigated the expression and distribution of ACE2- and TMPRSS2-expressing cells in the thyroid gland. RT-PCR and Western blotting were performed on human thyroid follicular cells (Nthy-ori3-1) and rat thyroid tissues to detect the expression levels of ACE and TMPRSS2 mRNA and proteins. We also analyzed the expression patterns of ACE2 and TMPRSS2 in 9 Sprague-Dawley rats and 15 human thyroid tissues, including 5 normal, 5 with Hashimoto's thyroiditis, and 5 with Graves' disease, by immunohistochemistry (IHC) and immunofluorescence. Both ACE2 and TMPRSS2 mRNAs and proteins were detected in the thyroid tissue. However, ACE2 and TMPRSS2 proteins were not expressed in thyroid follicular cells. In IHC, ACE2 and TMPRSS2 were not stained in the follicular cells. No cells co-expressed ACE2 and TMPRSS2. ACE2 was expressed in pericytes between follicles, and TMPRSS2 was mainly stained in the colloid inside the follicle. There was no difference in expression between the normal thyroid, Hashimoto's thyroiditis, and Graves' disease. SARS-CoV-2 does not directly invade the thyroid follicular cells. Whether SARS-CoV-2 infection of pericytes can affect COVID-19-related thyroid dysfunction warrants further study.

Tonsil mesenchymal stem cells-derived extracellular vesicles prevent submandibular gland dysfunction in ovariectomized rats

Dry mouth that occurs after menopause significantly reduces the quality of life of the elderly. The extracellular vesicles derived from mesenchymal stem cells are being studied for application in various pathological conditions in the field of tissue regenerative medicine. This study is to investigate the therapeutic effect on salivary gland dysfunction occurring after ovariectomy using tonsil mesenchymal stem cells (T-MSCs)-derived extracellular vesicles. The rats were divided into the following groups: sham-operated rats (SHAM), rats that underwent ovariectomy (OVX), and rats that underwent OVX surgery and were simultaneously injected with T-MSC-derived extracellular vesicles (OVX+EV). The rats were sacrificed 6 weeks after ovariectomy. Estradiol levels decreased in the OVX group compared with those in the SHAM group. Extracellular vesicles had no effect on estradiol levels or estrogen receptor β expression. The evaluation of pro-inflammatory cytokines, TNF-α and IL-6, increased in the OVX group and decreased in the OVX+EV group. The expressions of collagen I and TGFβI increased in the OVX group but decreased in the OVX+EV group. Moreover, to examine submandibular gland function, AQP5 and α-amylase expressions were downregulated in the OVX group, but improved upon exosome injection. In conclusion, T-MSC-derived extracellular vesicles are useful for the prevented submandibular gland dysfunction that occurs after menopause.

ACE2 and TMPRSS2 immunolocalization and oral manifestations of COVID-19

OBJECTIVES

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) entry into the host cells depends on the expression of angiotensin-converting enzyme 2 (ACE2) and transmembrane protease serine 2 (TMPRSS2). We investigated the distribution of ACE2- and TMPRSS2-expressing cells in various oral tissues to identify the underlying mechanism of oral manifestations in patients with coronavirus disease 2019. Subjects We analysed the expression patterns of ACE2 and TMPRSS2 in the oral mucosa (tongue, palate, and buccal mucosa), trigeminal ganglion, vessels, and salivary glands of 9 Sprague-Dawley rats using immunohistochemistry and immunofluorescence.

RESULTS

ACE2 and TMPRSS2 were strongly expressed in the intermediate layer of the squamous epithelia of tongue papillae and buccal mucosa. ACE2- and TMPRSS2-positive cells were observed in the taste buds of the tongue. Additionally, ACE2 and TMPRSS2 were co-expressed in the ductal epithelium and acinar cells of salivary glands. Furthermore, both ACE2 and TMPRSS2 were stained in the neuronal cell body of trigeminal ganglia, but not in Schwann cells. Moreover, ACE2 and TMPRSS2 were expressed in capillaries, but not in venules/arterioles.

CONCLUSIONS

SARS-CoV-2 can spread the suprabasal area of squamous epithelia of the oral mucosa, invades taste bud, trigeminal nerve, parotid gland, and microvessel, resulting in oral manifestations.

Perfusion-Decellularized Larynx as a Natural 3D Scaffold in a Rabbit Model

INTRODUCTION

Decellularized larynges could be used as scaffolds to regenerate the larynx. The purpose of this study was to establish a perfusion decellularization protocol to produce a 3-dimensional whole laryngeal extracellular matrix (ECM) scaffold in a rabbit model.

METHODS

The larynges of 20 rabbits assigned to the study group were harvested and decellularized using a perfusion decellularization protocol, while the larynges of 10 rabbits in the control group were harvested and untreated. Macroscopic and microscopic morphological analyses, a molecular analysis, a cellular content analysis, and scanning electron microscopy were performed.

RESULTS

A histological analysis showed the absence of cellular components, the presence of the ECM, and an intact cartilage structure filled with chondrocytes. The mean total DNA amounts of the native larynx, decellularized larynx, and decellularized cartilage-free larynx were 1,826.40, 434.70, and 41.40 μg/µL, respectively; those for the decellularized larynx and decellularized cartilage-free larynx were significantly lower (p < 0.001 and p < 0.001, respectively). The total amount of DNA in the decellularized sample was significantly lower compared to that in the native sample, at 57.2% in cartilage (p < 0.001), 2.4% in the thyroid gland (p < 0.001), 2.7% in muscle (p < 0.001), 1.6% in vessels (p < 0.001), and 4.8% in the vocal cords (p < 0.001).

CONCLUSION

Our perfusion decellularization protocol is feasible and reproducible to produce a 3-dimensional whole laryngeal ECM scaffold in a rabbit.

Clinical outcomes of T4a papillary thyroid cancer with recurrent laryngeal nerve involvement: a retrospective analysis

Preoperative vocal cord palsy (VCP) may indicate locally invasive papillary thyroid cancer (PTC); using this relationship, we evaluated the clinical outcomes and risk factors for recurrence in post-thyroidectomy T4a PTC patients with recurrent laryngeal nerve (RLN) involvement. We retrospectively investigated thyroidectomy patients, recorded their clinical factors, recurrence rate, and pathological findings, and analysed the relationship between recurrence rate and clinical factors. Of 72 patients, 37 (51%) had preoperative VCP and 35 (49%) had normal preoperative vocal cord movement with confirmed intraoperative RLN invasion. Tracheal and esophageal invasion was observed in 13 (18%) and 15 (21%) patients, respectively. Thyroid cancer recurred in 18 (25%) patients over 58 months, resulting in 2 (3%) deaths. Recurrence was not associated with surgical extent, organ invasion, enlarged tumour size, or lymph node infiltration (p > 0.05). The recurrence rate was significantly higher in patients with positive resection margins (p < 0.05). T4a PTC patients with RLN involvement showed a poor prognosis. The recurrence rate was not affected by preoperative VCP, intraoperative detection of RLN invasion, nerve resection, nerve preservation by shaving, lymph node metastasis, or tracheal or esophageal invasion. The most important prognostic factor for recurrence was a positive resection margin.

Risk factors of suprasternal lymph node metastasis in papillary thyroid carcinoma with clinical lateral cervical lymph node metastasis

Background

Metastatic lymph nodes are occasionally found in suprasternal lymph nodes in patients with papillary thyroid cancer (PTC). However, limited studies have examined these lymph nodes thus far. Therefore, we investigated the frequency and risk factors of suprasternal lymph node metastasis in patients with PTC and lateral cervical lymph node metastasis.

Methods

A total of 85 patients with cN1b PTC underwent total thyroidectomy, central neck dissection, and ipsilateral selective neck dissection including suprasternal lymph node dissection. We analyzed the correlation between suprasternal lymph node metastasis and sex, age, tumor characteristics, and cervical lymph node metastasis status.

Results

Eleven (12.9%) patients had pathological suprasternal lymph node metastasis. Suprasternal lymph node metastasis was associated with tumors located in the inferior pole of the thyroid gland and level IV lymph node metastasis (P=0.005 and 0.014, respectively). Receiver operating characteristic curve analysis indicated that two or more level IV metastatic lymph nodes had the best predictive value for suprasternal lymph node metastasis (P<0.001).

Conclusions

In patients with cN1b PTC, especially those with tumors in the inferior pole of the thyroid gland or level IV lymph node metastasis, greater attention should be paid to the suprasternal lymph nodes and suprasternal lymph node dissection should be routinely included as part of selective neck dissection.

sEVs from tonsil-derived mesenchymal stromal cells alleviate activation of hepatic stellate cells and liver fibrosis through miR-486-5p

Mesenchymal stromal cells (MSCs) are considered as a promising therapeutic tool for liver fibrosis, a main feature of chronic liver disease. Because small extracellular vesicles (sEVs) harboring a variety of proteins and RNAs are known to have similar functions with their derived cells, MSC-derived sEVs carry out the regenerative capacities of MSCs. Human tonsil-derived MSCs (T-MSCs) are reported as a novel source of MSCs, but their effects on liver fibrosis remain unclear. In the present study, we investigated the effects of T-MSC-derived sEVs on liver fibrosis. The expression of profibrotic genes decreased in human primary hepatic stellate cells (pHSCs) co-cultured with T-MSCs. Treatment of T-MSC-sEVs inactivated human and mouse pHSCs. Administration of T-MSC-sEVs ameliorated hepatic injuries and fibrosis in chronically damaged liver induced by carbon tetrachloride (CCl₄). miR-486-5p highly enriched in T-MSC-sEVs targeting the hedgehog receptor, smoothened (Smo), was upregulated, whereas Smo and Gli2, the hedgehog target gene, were downregulated in pHSCs and liver tissues treated with T-MSC-sEVs or miR-486-5p mimic, indicating that sEV-miR-486 inactivates HSCs by suppressing hedgehog signaling. Our results showed that T-MSCs attenuate HSC activation and liver fibrosis by delivering sEVs, and miR-486 in the sEVs inactivates hedgehog signaling, suggesting that T-MSCs and their sEVs are novel anti-fibrotic therapeutics for treating chronic liver disease.

The mechanism of submandibular gland dysfunction after menopause may be associated with the ferroptosis

Salivary gland dysfunction is a common symptom that occurs after menopause. This study was performed to investigate the mechanism of salivary gland dysfunction to confirm the relationship between ferroptosis and salivary gland dysfunction by ovariectomy. Forty-eight female rats were randomly divided into four groups (12 rats in each group). Histology, real time PCR, western blot, immunohistochemistry, electron microscopy, cytosolic iron assay, and salivary function were analyzed. Human salivary gland tissue analysis was also done. Lipogenesis and lipid deposition in the submandibular gland tissue occurred after ovariectomy. ROS generation, MDA+HAE was increased and GPX4 activity was decreased and in the OVX group compared to the CON group. Iron deposition in the submandibular gland tissue was increased in the OVX group. Submandibular gland fibrosis was increased and saliva secretion was decreased in the OVX group. In human submandibular gland analysis, lipid and iron deposition was also increased in the postmenopause group. This is the first in vivo study in which salivary gland dysfunction is associated with the ferroptosis in postmenopausal animal model. Increased lipid and iron deposition in normal submandibular gland tissues of postmenopausal women can suggest that the salivary gland dysfunction after menopause may be associated with the ferroptosis.

Effects of N-acetylcysteine inhalation therapy on the quality of life of patients with head and neck cancer who are receiving radiation therapy: a prospective non-randomized controlled multi-center study

BACKGROUNDS AND PURPOSE

Radiation therapy is an important mode of treatment for patients with head and neck cancers, but some associated complications can reduce the quality of life. We investigated whether N-acetylcysteine inhalation therapy improved the quality of life of such patients.

MATERIALS AND METHODS

We designed a prospective, non-randomized controlled multi-center study involving 10 institutions. We enrolled 120 patients (80 in the experimental group and 40 in the control group). Patients in the experimental group inhaled nebulized liquid N-acetylcysteine (2400 mg daily) for 8 weeks from the start of radiation therapy. Quality of life was assessed using the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire H&N 35.

RESULTS

N-acetylcysteine inhalation was not associated with any side effect or discomfort. The reduction in painkiller use from the end of N-acetylcysteine inhalation therapy to the 1-month follow-up was greater in the experimental group than in the control group (P = 0.014). Dry mouth symptoms also improved significantly in the experimental group (P = 0.019).

CONCLUSION

N-acetylcysteine inhalation improves the quality of life of patients with head and neck cancers who are receiving radiation therapy, without any specific side effect.

Application of Novel Intraoperative Neuromonitoring System Using an Endotracheal Tube With Pressure Sensor During Thyroid Surgery: A Porcine Model Study

OBJECTIVES

The loss of signal during intraoperative neuromonitoring (IONM) using electromyography (EMG) in thyroidectomy is one of the biggest problems. We have developed a novel IONM system with an endotracheal tube (ETT) with an attached pressure sensor instead of EMG to detect laryngeal twitching. The aim of the present study was to investigate the feasibility and reliability of this novel IONM system using an ETT with pressure sensor during thyroidectomy in a porcine model.

METHODS

We developed an ETT-attached pressure sensor that uses the piezoelectric effect to measure laryngeal muscle twitching. Stimulus thresholds, amplitude, and latency of laryngeal twitching evaluated using the pressure sensor were compared to those measured using transcartilage needle EMG. The measured amplitude changes by EMG and the pressure sensor during recurrent laryngeal nerve (RLN) traction injury were compared.

RESULTS

No significant differences in stimulus threshold intensity between EMG and the pressure sensor were observed. The EMG amplitude detected at 0.3 mA, increased with increasing stimulus intensity. When the stimulus was more than 1.0 mA, the amplitude showed a plateau. In a RLN traction injury experiment, the EMG amplitude did not recover even 20 minutes after stopping RLN traction. However, the pressure sensor showed a mostly recovery.

CONCLUSION

The change in amplitude due to stimulation of the pressure sensor showed a pattern similar to EMG. Pressure sensors can be feasibly and reliably used for RLN traction injury prediction, RLN identification, and preservation through the detection of laryngeal muscle twitching. Our novel IONM system that uses an ETT with an attached pressure sensor to measure the change of surface pressure can be an alternative to EMG in the future.

Application of an Intraoperative Neuromonitoring System Using a Surface Pressure Sensor in Parotid Surgery: A Rabbit Model Study

Objectives

Facial nerve monitoring (FNM) can be used to identify the facial nerve, to obtain information regarding its course, and to evaluate its status during parotidectomy. However, there has been disagreement regarding the efficacy of FNM in reducing the incidence of facial nerve palsy during parotid surgery. Therefore, instead of using electromyography (EMG) to identify the location and state of the facial nerve, we applied an intraoperative neuromonitoring (IONM) system using a surface pressure sensor to detect facial muscle twitching. The objective of this study was to investigate the feasibility of using the IONM system with a surface pressure sensor to detect facial muscle twitching during parotidectomy.

Methods

We evaluated the stimulus thresholds for the detection of muscle twitching in the orbicularis oris and orbicularis oculi, as well as the amplitude and latency of EMG and the surface pressure sensor in 13 facial nerves of seven rabbits, using the same stimulus intensity.

Results

The surface pressure sensor detected muscle twitching in the orbicularis oris and orbicularis oculi in response to a stimulation of 0.1 mA in all 13 facial nerves. The stimulus threshold did not differ between the surface pressure sensor and EMG.

Conclusion

The application of IONM using a surface pressure sensor during parotidectomy is noninvasive, reliable, and feasible. Therefore, the IONM system with a surface pressure sensor to measure facial muscle twitching may be an alternative to EMG for verifying the status of the facial nerve.

Clinical Significance of the Preoperative Thyroidectomy-Related Voice Questionnaire Score in Thyroid Surgery

BACKGROUND

The thyroidectomy-related voice questionnaire (TVQ) is an efficient screening tool for detecting postoperative vocal dysfunction. The aim of this study was to confirm the significance of the preoperative TVQ score in thyroid surgery.

METHODS

We examined 180 women who underwent total thyroidectomy with central lymph node dissection from March 2014 to May 2016. Based on the preoperative TVQ score, participants were categorized under "normal" (TVQ score <5) and "abnormal" (TVQ score ≥5) groups. The laryngoscopic examination and acoustic analysis were performed and the TVQ score assessed before and after surgery (2 weeks, 2 months, and 8 months).

RESULTS

In the normal group, the TVQ score increased up to 2 months postoperatively and had decreased at 8 months postoperatively but was significantly higher than the preoperative TVQ score. In the abnormal group, the TVQ score increased up to 2 months postoperatively but had recovered similar to the preoperative TVQ score 8 months postoperatively. The preoperative TVQ score in the abnormal group moderately correlated with the final TVQ score; however, the preoperative TVQ score in the normal group did not correlate with the TVQ score 8 months postoperatively.

CONCLUSION

During preoperative patient counseling, it is important to explain that voice changes without vocal cord palsy may occur postoperatively and that it may take a long time to resolve, particularly in patients with a normal preoperative TVQ score.

Application of Attachable Magnetic Nerve Stimulator in Intraoperative Facial Nerve Monitoring during Ear Surgery

We developed an attachable magnetic nerve stimulator (AMNS) that connects the metallic instruments to a neurophysiological monitoring unit for monitoring the facial nerve (FN) during ear surgery and present our experiences with intraoperative neuromonitoring (IONM) of the FN using AMNS. The FN in 20 patients who underwent tympanomastoidectomy for chronic ear disease was examined. The electromyography (EMG) amplitudes of the FN using AMNS were assessed. The EMG amplitudes of the FN at 1.00-mA stimulation during drilling were 265 ± 64 µV in the orbicularis oris and 288 ± 57 µV in the orbicularis oculi. The EMG amplitudes using AMNS attached to the surgical instruments under 0.35-mA stimulus at the tympanic segment of the FN were 196 ± 43 µV in the orbicularis oris and 197 ± 41 µV in the orbicularis oculi. The application of continuous stimulation with burr and surgical instruments using the AMNS is feasible and effective for FN stimulation and identification.

Human Tonsil-Derived Mesenchymal Stromal Cells Maintain Proliferating and ROS-Regulatory Properties via Stanniocalcin-1

Mesenchymal stromal cells (MSCs) from various sources exhibit different potential for stemness and therapeutic abilities. Recently, we reported a unique MSCs from human palatine tonsil (TMSCs) and their superior proliferation capacity compared to MSCs from other sources. However, unique characteristics of each MSC are not yet precisely elucidated. We investigated the role of stanniocalcin-1 (STC1), an anti-oxidative hormone, in the functions of TMSCs. We found that STC1 was highly expressed in TMSC compared with MSCs from bone marrow or adipose tissue. The proliferation, senescence and differentiation of TMSCs were assessed after the inhibition of STC1 expression. STC1 inhibition resulted in a significant decrease in the proliferation of TMSCs and did not affect the differentiation potential. To reveal the anti-oxidative ability of STC1 in TMSCs themselves or against other cell types, the generation of mitochondrial reactive oxygen species (ROS) in TMSC or ROS-mediated production of interleukin (IL)-1β from macrophage-like cells were detected. Interestingly, the basal level of ROS generation in TMSCs was significantly elevated after STC1 inhibition. Moreover, down-regulation of STC1 impaired the inhibitory effect of TMSCs on IL-1β production in macrophages. Taken together, these findings indicate that STC1 is highly expressed in TMSCs and plays a critical role in proliferating and ROS-regulatory abilities.

The Protective Effect of Echinochrome A on Extracellular Matrix of Vocal Folds in Ovariectomized Rats

Here, we investigated the effects of sex hormones on extracellular matrix (ECM)-related gene expression in the vocal fold lamina propria of ovariectomized (after ovary removal) rats and verified whether echinochrome A (ECH) exerts any therapeutic effects on ECM reconstitution after estrogen deficiency in ovariectomized rats. Sprague–Dawley female rats (9 weeks old) were acclimatized for a week and randomly divided into three groups (n = 15 each group) as follows: group I (sham-operated rats, SHAM), group II (ovariectomized rats, OVX), group III (ovariectomized rats treated with ECH, OVX + ECH). Rats from the OVX + ECH group were intraperitoneally injected with ECH at 10 mg/kg thrice a week after surgery for 6 weeks. And rats were sacrificed 6 weeks after ovariectomy. Estradiol levels decreased in OVX group compared with the SHAM group. ECH treatment had no effect on the levels of estradiol and expression of estrogen receptor β (ERβ). The evaluation of ECM components showed no significant changes in elastin and hyaluronic acid levels between the different groups. Collagen I and III levels were lower in OVX group than in SHAM group but increased in OVX + ECH group. The mRNA levels of matrix metalloproteinase (MMP)-1, -2, -8, and -9 were significantly higher in the OVX group than in the SHAM group, but decreased in the OVX + ECH group. Thus, changes were observed in ECM-related genes in the OVX group upon estradiol deficiency that were ameliorated by ECH administration. Thus, the vocal fold is an estradiol-sensitive target organ and ECH may have protective effects on the ECM of vocal folds in ovariectomized rats.

Increased calcium channel in the lamina propria of aging rat

The alterations of the extracellular matrix (ECM) in lamina propria of the vocal folds are important changes that are associated with decreased vibrations and increased stiffness in aging vocal fold. The aim of this study was to investigate the differences in gene expression of lamina propria using next generation sequencing (NGS) in young and aging rats and to identify genes that affect aging-related ECM changes for developing novel therapeutic target molecule. Among the 40 genes suggested in the NGS analysis, voltage-gated calcium channels (VGCC) subunit alpha1 S (CACNA1S), VGCC auxiliary subunit beta 1 (CACNB1), and VGCC auxiliary subunit gamma 1 (CACNG1) were increased in the lamina propria of the old rats compared to the young rats. The synthesis of collagen I and III in hVFFs decreased after si-CACNA1S and verapamil treatment. The expression and activity of matrix metalloproteinases (MMP)-1 and -8 were increased in hVFFs after the treatment of verapamil. However, there was no change in the expression of MMP-2 and -9. These results suggest that some calcium channels may be related with the alteration of aging-related ECM in vocal folds. Calcium channel has promising potential as a novel therapeutic target for the remodeling ECM of aging lamina propria.

Development of a Novel Intraoperative Neuromonitoring System Using an Accelerometer Sensor in Thyroid Surgery: A Porcine Model Study

Objectives.

The sensitivity and positive predictive value of widely used intraoperative neuromonitoring (IONM) using electromyography (EMG) of the vocalis muscle in thyroid surgery are controversial. Thus, we developed a novel IONM system with an accelerometer sensor that uses the piezoelectric effect instead of EMG to detect laryngeal twitching. The objective of this study was to evaluate the feasibility and safety of this novel IONM system during thyroid surgery in a porcine model.

Methods.

We developed an accelerometer sensor that uses the piezoelectric effect to measure laryngeal twitching in three dimensions. This novel accelerometer sensor was placed in the anterior neck skin (transcutaneous) or postcricoid area. Stimulus thresholds, amplitude, and latency of laryngeal twitching measured using the accelerometer sensor were compared to those measured through EMG of the vocalis muscle.

Results.

The amplitudes of the accelerometer sensor at the anterior neck and postcricoid area were significantly lower than those of EMG because of differences in the measurement method used to evaluate laryngeal movement. However, no significant differences in stimulus thresholds between the EMG endotracheal tube and transcutaneous or postcricoid accelerometer sensors were observed.

Conclusion.

Accelerometer sensors located at the anterior neck or postcricoid area were able to identify laryngeal twitching. The stimulus intensity measured with these sensors was equivalent to that from conventional vocalis EMG. Our novel IONM system with an accelerometer sensor that checks changes in surface acceleration can be an alternative to EMG of the vocalis muscle for IONM in the future.

Effect of sex hormones on extracellular matrix of lamina propria in rat vocal fold

OBJECTIVES

The role of sex hormones for voice changes in men and women is presently unknown. To determine the effect of sex hormone on the vocal fold, changes of the extracellular matrix (ECM) in vocal fold lamina propria were assessed in orchiectomized (ORX) and ovariectomized (OVX) rats.

METHODS

Male and female Sprague-Dawley rats were divided into sham-operated control male (CON-ORX), ORX, sham-operated female (CON-OVX), and OVX rats. Histological changes and expression of ECM-related genes in lamina propria of the vocal fold were evaluated at 4 and 12 weeks after surgery.

RESULTS

Testosterone and estradiol levels decreased in the ORX and OVX groups, respectively. ORX groups did not have significant changes compared with CON-ORX groups. However, the expression of hyaluronic acid (HA) was decreased in the OVX group compared with the CON-OVX group. The expression of collagen I in OVX was lower than in the CON-OVX group. Collagen III levels were elevated at 4 weeks in the OVX group, but collagen III levels were diminished at 12 weeks in the OVX group. Expression of elastin in the ECM was less dense in the OVX group compared with controls. The expression MMP-1 and MMP-9 showed significantly increase in the OVX group compared to the CON-OVX group.

CONCLUSION

No changes of the ECM-related genes in the vocal fold lamina propria were observed in ORX groups with reduced testosterone. However, changes of several ECM-related genes were observed in OVX groups with decreased estrogen. These results indicate that the vocal fold is an estrogen-sensitive target organ and that decreased estrogen, not testosterone, can affect the expression of several ECM-related molecules of vocal fold.

LEVEL OF EVIDENCE

NA Laryngoscope, 130:732-740, 2020.

Preoperative serum VEGF-C but not VEGF-A level is correlated with lateral neck metastasis in papillary thyroid carcinoma

BACKGROUND

This study aimed to investigate the relationships between serum vascular endothelial growth factor (VEGF)-A or VEGF-C levels and lymph node metastasis (LNM) status in patients with papillary thyroid carcinoma (PTC).

METHODS

The study enrolled 150 patients with pathologically proven PTC who underwent surgery: PTC without LNM, PTC with central neck metastasis, and PTC with lateral neck metastasis.

RESULTS

Preoperative serum VEGF-A levels were 300.12 ± 80.80 pg/mL overall and were not correlated with the presence of LNM. Preoperative serum VEGF-C levels were 132.41 ± 48.48 pg/mL overall and were significantly correlated with the presence of LNM. Serum VEGF-C levels were further increased in patients with lateral neck metastasis and positively correlated with the number of metastatic LNs (rho = 0.252, P = 0.002). Serum VEGF-C, but not VEGF-A, was identified as a significant predictor of lateral neck metastasis.

CONCLUSION

Serum VEGF-C might be a clinically relevant biomarker of lateral neck metastasis in patients with PTC.

Guidelines for the Surgical Management of Oral Cancer: Korean Society of Thyroid-Head and Neck Surgery

Korean Society of Thyroid-Head and Neck Surgery appointed a Task Force to provide guidance on the implementation of a surgical treatment of oral cancer. MEDLINE databases were searched for articles on subjects related to “surgical management of oral cancer” published in English. Results were restricted to systematic reviews, randomized control trials/controlled clinical trials, and observational studies. The quality of evidence was rated with use RoBANS (Risk of Bias Assessment Tool for Nonrandomized Studies) and AMSTAR (A Measurement Tool to Assess the Methodological Quality of Systematic Reviews). Evidence-based recommendations for practice were ranked according to the American College of Physicians grading system. Additional directives are provided as expert opinions and Delphi questionnaire when insufficient evidence existed. The Committee developed 68 evidence-based recommendations in 34 categories intended to assist clinicians and patients and counselors, and health policy-makers. Proper surgical treatment selection for oral cancer, which is directed by patient- and subsite-specific factors, remains the greatest predictor of successful treatment outcomes. These guidelines are intended for use in conjunction with the individual patient’s treatment goals.

Development of a Novel Intraoperative Neuromonitoring System Using a Surface Pressure Sensor to Detect Muscle Movement: A Rabbit Model Study

OBJECTIVES

False-negative or false-positive responses in intraoperative neuromonitoring (IONM) using electromyography (EMG) in thyroid surgery pose a challenge. Therefore, we developed a novel IONM system that uses a surface pressure sensor instead of EMG to detect muscle twitching. This study aimed to investigate the feasibility and safety of a new IONM system using a piezo-electric surface pressure sensor in an experimental animal model.

METHODS

We developed the surface pressure sensor by modifying a commercial piezo-electric sensor. We evaluated the stimulus thresholds to detect muscle movement, as well as the amplitude and latency of the EMG and surface pressure sensor in six sciatic nerves of three rabbits, according to the stimulus intensity.

RESULTS

The surface pressure sensor detected the muscle movements in response to a 0.1 mA stimulation of all six sciatic nerves. There were no differences in the thresholds of stimulus intensity between the surface pressure sensor and EMG recordings to detect muscle movements.

CONCLUSION

It is possible to measure the change in surface pressure by using a piezo-electric surface pressure sensor instead of EMG to detect muscle movement induced by nerve stimulation. The application of IONM using a piezo-electric surface pressure sensor during surgery is noninvasive, safe, and feasible. Measuring muscle twitching to identify the state of the nerves using the novel IONM system can be an alternative to recording of EMG responses.

Development of a Novel Detachable Magnetic Nerve Stimulator for Intraoperative Neuromonitoring

BACKGROUND

Recurrent laryngeal nerve (RLN) palsy is a serious complication of thyroid surgery. During intraoperative neuromonitoring (IONM) of the RLN in thyroid surgery, repeated shifting between surgical instruments and the nerve stimulator is cumbersome and time-consuming. Therefore, we developed a simple detachable magnetic nerve stimulator that may be connected to all metallic surgical instruments. This study aimed to investigate the feasibility and efficacy of this detachable magnetic nerve stimulator for IONM in a porcine model and humans.

METHODS

Eight RLNs in four pigs and thirteen in nine patients that underwent thyroidectomy were examined. We developed a detachable nerve stimulator that combined surgical instruments with the nerve-stimulating probe. We evaluated the electromyography (EMG) amplitudes of the RLNs in pigs and patients using conventional nerve probes and surgical instruments with the novel detachable magnetic nerve stimulator attached.

RESULTS

The EMG amplitudes of the eight RLNs in pigs and thirteen in patients were analyzed. The detachable magnetic nerve stimulator was feasible and safe. There was no significant difference in the EMG amplitude between instruments (P = 0.423 in animals, P = 0.446 in humans).

CONCLUSIONS

The application of stimulating dissection using a detachable magnetic nerve stimulator during thyroidectomy with IONM is simple, convenient, and effective. It provides surgeons with real-time feedback of the EMG response during intermittent IONM. We propose that this novel device could be an essential guide for most surgeons, especially for less experienced head and neck surgeons.

Regenerative potential of tonsil mesenchymal stem cells on surgical cutaneous defect

As tissue engineering and regenerative medicine have evolved recently, stem cell therapy has been investigated in the field of impaired wound healing. Several studies have reported that mesenchymal stem cells derived from various tissues including bone marrow and adipose tissue can exert the regenerative efficacy in the wound healing. Previously, we have demonstrated the isolation and characterization of tonsil-derived mesenchymal stem cells (TMSCs) with excellent proliferative property. In the present study, we aimed to evaluate the regenerative efficacy of TMSCs in the wound healing process. Two distinct cutaneous surgical defects were generated in the dorsum of mice. Each wound was treated with TMSCs or phosphate-buffered saline (PBS), respectively. After sacrifice, the skin and subcutaneous tissues around the surgical defect were harvested and assessed for inflammation, re-epithelialization, dermal regeneration, and granulation tissue formation. The administration of TMSCs into wound beds significantly promoted the repair of surgical defects in mice. Especially, TMSCs efficiently contributed to the attenuation of excessive inflammation in the surgical lesion, as well as the augmentation of epidermal and dermal regeneration. To elucidate the underlying mechanisms, TMSCs were analyzed for their potency in immunomodulatory ability on immune cells, stimulatory effect on the proliferation of keratinocytes, and fibroblasts, as well as the regulation of fibroblast differentiation. TMSCs inhibited the non-specific or T-cell-specific proliferation of peripheral blood mononuclear cells, as well as the M1 polarization of macrophage-like cells. Moreover, TMSCs augmented the proliferation of skin-constituting fibroblasts and keratinocytes while they suppressed the differentiation of fibroblasts into myofibroblasts. Taken together, our findings demonstrate the regenerative potential of TMSCs in wound healing process through the regulation on inflammation, proliferation, and remodeling of various skin cells, implying that TMSCs can be a promising alternative for wound repair.

Development of an Attachable Endoscopic Nerve Stimulator for Intraoperative Neuromonitoring during Endoscopic or Robotic Thyroidectomy

We developed a simple attachable endoscopic nerve stimulator that can be connected to monopolar cauterization surgical instruments. This study on porcine models aimed to investigate the feasibility and efficacy of an attachable endoscopic nerve stimulator for intraoperative neuromonitoring (IONM) before application in humans. We evaluated the electromyography (EMG) amplitudes of 8 recurrent laryngeal nerves in 4 pigs with a conventional nerve probe and the attachable endoscopic nerve stimulator. The attachable endoscopic nerve stimulator was feasible and safe in all cases. There was no significant difference in the EMG amplitude of the recurrent laryngeal nerve among instruments ( P = .429). The application of stimulating dissection with an attachable endoscopic nerve stimulator during endoscopic or robotic thyroidectomy with IONM is simple, convenient, and effective. It provides surgeons with real-time feedback of the EMG response during intermittent IONM. We believe that this novel device could be an essential guide and functional navigator for most surgeons, especially for less experienced ones.

Prognostic implication of fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography in patients with recurrent papillary thyroid cancer

BACKGROUND

Fluorine-18 fluorodeoxyglucose positron emission tomography/CT (¹⁸ F-FDG PET/CT) has been widely accepted as an effective method for detecting recurrent papillary thyroid cancer (PTC) in patients with increased serum thyroglobulin (Tg) or Tg antibody (TgAb) levels and negative whole-body scintigraphy (WBS) results. The role of WBS as a diagnostic tool in detecting recurrence has relatively decreased recently. However, only a few studies have examined the usefulness of ¹⁸ F-FDG PET/CT for evaluating patients with recurrent PTC, regardless of the WBS results. The purpose of this analysis was to evaluate the diagnostic value and prognostic role of ¹⁸ F-FDG PET/CT for patients with recurrent PTC, irrespective of their WBS results.

METHODS

Sixty-six patients with locoregional recurrent PTC who underwent ¹⁸ F-FDG PET/CT and neck CT within 6 months before surgical treatment were included in this retrospective analysis. Imaging findings were compared with postoperative histopathologic results. The diagnostic values of ¹⁸ F-FDG PET/CT and neck CT were compared according to the serum Tg and TgAb levels and cervical levels. Each patient's status at the last follow-up was also reviewed, and survival probabilities were estimated using the Kaplan-Meier plot.

RESULTS

The sensitivity, specificity, and diagnostic accuracy of ¹⁸ F-FDG PET/CT for the entire patient group were 38.5%, 90.2%, and 58.3%, respectively. The corresponding neck CT values were 55.0%, 85.7%, and 66.7%, respectively. According to the serum Tg and TgAb levels, except for the specificity, most diagnostic values of ¹⁸ F-FDG PET/CT were worse than those of the neck CTs, with or without statistical significance. For the high maximum standardized uptake value (SUVmax) group (SUVmax >10) and the low SUVmax group, the median locoregional disease-free survival times were 33.3 months and 81.8 months, respectively (P < .001).

CONCLUSION

The diagnostic value of ¹⁸ F-FDG PET/CT for localizing recurrent lesions was worse than that of the neck CT, irrespective of the WBS results. However, patients with a higher SUVmax showed a significantly worse prognosis than did those with a lower SUVmax. Therefore, we suggest that, in patients with recurrent PTC, ¹⁸ F-FDG PET/CT should be considered for prognostication rather than diagnosis.

Feasibility and safety of nerve stimulator attachment to energy-based devices: A porcine model study

BACKGROUND

Recently, several energy-based devices (EBDs) have been developed and applied in the context of thyroid surgery. EBDs can reduce operation time, blood loss, and postoperative pain. Compared to conventional electrocautery, EBDs operate at a relatively lower temperature and produce minimal lateral tissue damage. Yet, during device operation, the tip of the EBD is hot enough to cause thermal nerve damage, increasing the need for surgeons to be cautious about EBD application. To increase the safety of EBDs, we attached nerve stimulators to the tips of two EBDs and compared them to conventional monopolar nerve stimulation using a porcine model.

METHODS

Three piglets (30-40 kg) underwent total thyroidectomy after orotracheal intubation with a nerve integrity monitor (NIM) electromyography (EMG) endotracheal tube. Nerve stimulators were attached to two EBDs (Harmonic Focus^®+ and LigaSure™). After dissection and identification of six recurrent laryngeal nerves in the three piglets, both of the EBDs with attached nerve stimulators and a conventional monopolar nerve stimulator were applied near the nerve and EMG parameters were recorded using the NIM 3.0 system. The stimulus intensity was varied from 5 mA to 1 mA and the maximum distance and amplitude at which nerve detection was achieved were measured.

RESULTS

There were no statistically significant differences between the maximum distance or mean amplitude obtained from nerve stimulators attached to EBDs and those obtained from the conventional nerve stimulator. Additionally, there were no adverse EMG events related to the use of nerve stimulators attached to EBDs.

CONCLUSIONS

Attachment of a nerve stimulator to an EBD for nerve detection during thyroidectomy was as safe and effective as attachment of a conventional nerve stimulator. Use of a nerve stimulator attachment may reduce the likelihood of EBD-associated nerve damage during thyroid surgery.

Guidelines for the Surgical Management of Laryngeal Cancer: Korean Society of Thyroid-Head and Neck Surgery

Korean Society of Thyroid-Head and Neck Surgery appointed a Task Force to develop clinical practice guidelines for the surgical treatment of laryngeal cancer. This Task Force conducted a systematic search of the EMBASE, MEDLINE, Cochrane Library, and KoreaMed databases to identify relevant articles, using search terms selected according to the key questions. Evidence-based recommendations were then created on the basis of these articles. An external expert review and Delphi questionnaire were applied to reach consensus regarding the recommendations. The resulting guidelines focus on the surgical treatment of laryngeal cancer with the assumption that surgery is the selected treatment modality after a multidisciplinary discussion in any context. These guidelines do not, therefore, address non-surgical treatment such as radiation therapy or chemotherapy. The committee developed 62 evidence-based recommendations in 32 categories intended to assist clinicians during management of patients with laryngeal cancer and patients with laryngeal cancer, and counselors and health policy-makers.

Role of Fibroblast Growth Factor-5 on the Proliferation of Human Tonsil-Derived Mesenchymal Stem Cells

Human mesenchymal stem cells (MSCs) are a promising tool for therapeutic applications in cell-based therapy and regenerative medicine, and MSCs from the human palatine tonsils have recently been used as a new tissue source. However, the understanding of the proliferation and differentiation capacity of tonsil-derived MSCs (T-MSCs) is limited. In this study, we compared the proliferative potential of T-MSCs with those of bone marrow MSCs (BM-MSCs) and adipose tissue-derived MSCs (A-MSCs). Additionally, we investigated the underlying mechanism of T-MSC function. We showed that T-MSCs proliferated faster than A-MSCs and BM-MSCs in methylthiazolyl diphenyl-tetrazolium (MTT) assays, cell count assays, and cell cycle distribution analyses. DNA microarray and real-time PCR analyses revealed that the expression of fibroblast growth factor-5 (FGF5) was significantly elevated in T-MSCs compared with those in A-MSCs and BM-MSCs. Cell growth curves showed a difference in cell growth between untreated cells and siFGF5-treated T-MSCs. The administration of recombinant human FGF5 (rhFGF5) to the cells transfected with siFGF5 led to a significant increase in the proliferation rates. The administration of rhFGF5 to T-MSCs led to an increase in the levels of phosphorylated ERK1/2. However, treatment with siFGF5 resulted in an overall decrease in the level of phosphorylated ERK1/2. The osteogenic differentiation of T-MSCs was reduced following siFGF5 transfection, and it recovered to near-normal levels when rhFGF5 was added. These findings indicate that T-MSCs show significantly higher proliferative potential compared with those of BM-MSCs and A-MSCs. FGF5 facilitates cell proliferation through ERK1/2 activation, and it influences the osteogenic differentiation of T-MSCs.

Identification of differentially expressed genes between high and low marbling score grades of the longissimus lumborum muscle in Hanwoo (Korean cattle)

We conducted DD-RT-PCR analysis to identify differentially expressed genes between high and low marbling score groups with extremely different IMF content of the longissimus lumborum muscles in Hanwoo. We detected 137 DEGs between two marbling score groups. Of these DEGs, 41 DEGs were highly expressed in the high marbling score group, whereas 96 DEGs showed a higher expression in the low marbling score group. Among them, we selected eight DEGs exhibiting the greatest differential expression levels between two marbling score groups. These genes could be classified as five candidate genes according to homology to known genes and biological functions. The expression of four DEGs except for ATP6 gene was confirmed by qRT-PCR. The TPI1 gene was significantly higher expressed at the high marbling group, whereas ACTA1, TNNT1 and MDH2 genes were significantly higher expressed at the low marbling group. Therefore, the TPI1 gene was up-regulated, suggesting that this gene may have an important function related to IMF deposition.

Decellularization of Human Nasal Septal Cartilage for the Novel Filler Material of Vocal Fold Augmentation

OBJECTIVES

The clinical application of allogenic and/or xenogenic cartilage for vocal fold augmentation requires to remove the antigenic cellular component. The objective of this study was to assess the effect of cartilage decellularization and determine the change in immunogenicity after detergent treatment in human nasal septal cartilage flakes made by the freezing and grinding method.

METHODS

Human nasal septal cartilages were obtained from surgical cases. The harvested cartilages were treated by the freezing and grinding technique. The obtained cartilage flakes were treated with 1% Triton X-100 or 2% sodium dodecyl sulfate (SDS) for decellularization of the cartilage flakes. Hematoxylin and eosin stain (H&E stain), surface electric microscopy, immunohistochemical stain for major histocompatibility complex I and II, and ELISA for DNA contents were performed to assess the effect of cartilage decellularization after detergent treatment.

RESULTS

A total of 10 nasal septal cartilages were obtained from surgical cases. After detergent treatment, the average size of the cartilage flakes was significantly decreased. With H&E staining, the cell nuclei of decellularized cartilage flakes were not observed. The expression of major histocompatibility complex (MHC)-I and II antigens was not identified in the decellularized cartilage flakes after treatment with detergent. DNA content was removed almost entirely from the decellularized cartilage flakes.

CONCLUSION

Treatment with 2% SDS or 1% Triton X-100 for 1 hour appears to be a promising method for decellularization of human nasal septal cartilage for vocal fold augmentation.

Isolation and Localization of Mesenchymal Stem Cells in Human Palatine Tonsil by W5C5 (SUSD2)

BACKGROUND/AIMS

Although tonsil-mesenchymal stem cells (T-MSCs) have been studied as a new autologous or homologous source of MSCs, research on specific markers of MSCs and localization for purified T-MSC isolation has not yet been reported. This study investigates the expression of W5C5 (SUSD2) in tonsil stromal cells and the colony-forming ability and differentiation potential of W5C5+ cells to determine the usefulness of W5C5+ MSCs as a marker that can be used for the purification of T-MSCs. In addition, the location of W5C5+ cells expressed in the tonsil tissues is examined.

METHODS

T-MSCs were isolated from the tonsillar tissues of 12 patients undergoing tonsillectomy. The colony-forming ability, surface markers, proliferation potential, and differentiation capacities of purified W5C5+ MSCs, W5C5- MSCs, and unselected T-MSCs were evaluated. The location of the W5C5+ cells in the tonsillar tissues was also investigated by immunohistochemistry.

RESULTS

W5C5 was expressed in 2.5±0.4% of fresh human tonsil stromal cells. W5C5+ cells formed many colonies, but W5C5- cells did not form any colonies. The colony-forming number of W5C5+ cells (74.4 ± 9.8) was significantly higher than that of unselected tonsil stromal cells (23.6 ± 3.7). However, the differences in proliferation potential, surface marker expression, and differentiation potential between W5C5+ T-MSCs and unselected T-MSCs were not significant. W5C5+ cells were identified in the perivascular area around the blood vessels.

CONCLUSION

W5C5+ T-MSCs possessed typical MSC properties with high colony-forming efficiency, and niches of W5C5+ T-MSCs were located in the perivascular area of tonsil tissues. These findings suggest that W5C5 is a useful single marker for the isolation of purified T-MSCs.

Effects of donor age, long-term passage culture, and cryopreservation on tonsil-derived mesenchymal stem cells

OBJECTIVES

Human mesenchymal stem cells (MSCs) are efficacious in various cellular therapeutic applications and have been isolated from several tissues. Recent studies have reported that human tonsil tissue contains a new source of progenitor cells, potentially applicable for cell-based therapies. Information about the effects of donor age, long-term passage and cryopreservation are essential for clinical applications and cell-based therapies. Therefore, the authors investigated how the morphology, cell-surface markers, proliferation potential and differentiation capacity of tonsil-derived MSCs (T-MSCs) were affected by donor age, long-term passage, and cryopreservation.

MATERIALS AND METHODS

T-MSCs were isolated from tonsillar tissue of 20 patients undergoing tonsillectomy. Authors evaluated the effects of donor-age, long-term passage, and cryopreservation on the morphology, surface markers, proliferation potential and differentiation capacities of T-MSCs.

RESULTS

T-MSCs exhibited a fibroblast-like, spindle-shaped appearance. There were no significant morphological differences according to donor age, long-term passage or cryopreservation. T-MSCs isolated from donors of various ages were positive for markers CD90, CD44, and CD73, but negative for CD45, CD31, and HLA-DR. There were no significant differences in the expression of positive and negative surface markers as a function of donor age, long-term passage and cryopreservation. T-MSCs from different donor age groups showed similar proliferation potentials after passage 2. After long-term passage and cryopreservation, there were no significant morphological differences. Cryopreservation did not affect the proliferation potential of T-MSCs, but there was a significant decrease in the proliferation potential in long-term passage T-MSCs (passage 15). The effect of donor age, long-term passage and cryopreservation on the in vitro adipogenic, osteogenic, and chondrogenic differentiation potential of T-MSCs was not significant.

CONCLUSION

The effect of donor age, long-term passage culture, and cryopreservation on T-MSC properties are negligible, except for the proliferation capacity of long-term cultured T-MSCs. Therefore, T-MSCs are considered to be promising MSCs that can be used as future alternative sources for autologous or allogenic MSCs.

Development of inorganic and organic hybrid nanocoating based on carbon nanotubes for corrosion resistance

In this study, we report the synthesis and characterization of novel hybrid nanocoating based on carbon nanotubes (CNTs) on anodized aluminum surfaces (AAO). The hybrid nanocoating was deposited by number of methods which include spray coating, spin coating and dip coating. The bonding of nanocoating with metal surface is an important parameter for successful modification of the metal surfaces. The improved adhesion of nanocoating on metal surfaces could be attributed to chemical bonding of sol-gel nanocoating with anodized surfaces. The nanocoated anodized aluminum surfaces showed superior adhesion and excellent anticorrosive properties. The nanocoated panels showed enhanced galvanic protection comparable to 80% of titanium metal as determined by galvanic corrosion measurements. It also showed higher thermal conductivities than stainless steel and bare anodized surfaces.

Comparison of alfuzosin 10 mg with or without propiverine 10 mg, 20 mg in men with lower urinary tract symptom and an overactive bladder: randomised, single-blind, prospective study

PURPOSE

The efficacy and safety of treatment with alfuzosin 10 mg plus propiverine 10 or 20 mg in men with lower urinary tract symptoms (LUTS) and an overactive bladder were investigated.

MATERIALS AND METHODS

In this parallel-arm, prospective, multicentre, single-blind study, men who were ≥ 40 years old, had an International Prostate Symptom Score (IPSS) of ≥ 8, an Overactive Bladder Symptom Score (OABSS) of ≥ 3 and an OABSS urgency item score of ≥ 2 were randomised in a 1 : 1 :1 ratio to receive alfuzosin 10 mg alone (Group A) or with propiverine 10 mg (Group B) or 20 mg (Group C) for 8 weeks. Four and 8 weeks after commencing treatment, OABSS was measured along with IPSS, maximal urinary flow rate (Qmax ) and postvoid residual volume (PVR). Adverse events were recorded.

RESULTS

A total of 135 men, including 43 in Group A, 48 in Group B and 44 in Group C, completed the study. Relative to baseline, all groups demonstrated significant reductions in OABSS and the IPSS after eight treatment weeks (p < 0.005). The improvement of OABSS in Group C was significantly greater than Group A and B (Group A: 0.70 ± 1.94; Group B: 2.50 ± 2.98; Group C: 4.30 ± 3.40; p < 0.005). An observed improvement of Qmax and PVR in the three groups did not achieve statistical significance. Overall adverse event rates were higher in Group C but not significant compared with others.

CONCLUSION

In patients with LUTS and overactive bladder, combined therapy with alfuzosin 10 mg plus propiverine 20 mg was significantly more effective than alfuzosin monotherapy and propiverine 10 mg combined therapy in terms of improving OABSS while not significantly affecting Qmax or PVR.

Tumor location-dependent skip lateral cervical lymph node metastasis in papillary thyroid cancer

BACKGROUND

Lateral cervical lymph node metastasis without central lymph node (CLN) metastasis is not infrequent in papillary thyroid cancer (PTC). This study was designed to investigate the frequency and pattern of skip metastasis in PTC.

METHODS

We reviewed 131 patients who underwent total thyroidectomy with CLN dissection and selective lymph node dissection. Tumor location was classified in 3 areas (upper, middle, and lower third) based on preoperative ultrasonographic findings.

RESULTS

All skip metastases occurred in patients whose tumors had been on the upper part of the thyroid (p < .001). Among 9 patients with skip metastasis, level III lymph nodes (66.7%) were the lymph nodes that were most frequently involved in skip metastasis.

CONCLUSION

Primary tumors in the upper portion of the thyroid are closely linked to skip metastasis. Careful preoperative evaluation of lateral cervical lymph nodes is suggested when a tumor is in the upper portion.

Enhanced Controlled Transdermal Delivery of Ambroxol from the EVA Matrix

To avoid the systemic adverse effects that might occur after oral administration, transdermal delivery of ambroxol was studied as a method for maintaining proper blood levels for an extended period. Release of ambroxol according to concentration and temperature was determined, and permeation of drug through rat skin was studied using two chamber-diffusion cells. The solubility according to PEG 400 volume fraction was highest at 40% PEG 400. The rate of drug release from the EVA matrix increased with increased temperature and drug loading doses. A linear relationship existed between the release rate and the square root of loading rate. The activation energy (Ea) was measured from the slope of the plot of log P versus 1000/T and was found to be 10.71, 10.39, 10.33 and 9.87 kcal/mol for 2, 3, 4 and 5% loading dose from the EVA matrix, respectively. To increase the permeation rate of ambroxol across rat skin from the EVA matrix, various penetration enhancers such as fatty acids (saturated, unsaturated), propylene glycols, glycerides, pyrrolidones, and non-ionic surfactants were used. The enhancing effects of the incorporated enhancers on the skin permeation of ambroxol were evaluated using Franz diffusion cells fitted with intact excised rat skin at 37° using 40% PEG 400 solution as a receptor medium. Among the enhancers used, polyoxyethylene-2-oleyl ether increased the permeation rate by 4.25-fold. In conclusion, EVA matrix containing plasticizer and permeation enhancer could be developed for enhanced transdermal delivery of ambroxol.