Effect of photo-polymerization on flexural strength on hybrid composite resin for CAD/CAM milling / 대한치과재료학회지

The purpose of this study is to evaluate the effect of photo-polymerization on the mechanical strength of the hybrid resin block. Hybrid composite resin was fabricated by polymer matrix mixed with inorganic filler and various additive. Visible light (460 nm) LED curing device for photo-polymerization was designed and fabricated. Photo-polymerization of resin block was performed under 3 hrs at 1200 mW/cm2 , 2 hrs at 1600 mW/cm2 , 3 hrs at 1600 mW/cm2 , and 4 hrs at 1600 mW/cm2 of irradiation intensities and time. Mechanical strength was measured using flexural strength. In addition, the sample treated for 2 hrs at 1600 mW/cm2 was performed post-treatment under conditions of plasma surface treatment (100 W, 5 min) and light curing for 15 min in order to improve the degree of polymerization. And then specimen was measured for flexural strength again. After the photo-polymerization, surface morphology was analyzed by SEM. The flexural strength of the composite resin block was significantly increased as the irradiation time was increased. Especially, post-treated sample showed higher flexural strength than that of the other samples. In the SEM analysis, surface morphology was no significant difference regardless of the photo-polymerization conditions. Light irradiation and plasma treatment could be a powerful technique to improve the polymerization of hybrid composite resin block for CAD/CAM-processed prosthesis.

Schisandrol A and gomisin N from Schisandra chinensis extract improve hypogonadism via anti-oxidative stress in TM3 Leydig cells

BACKGROUND/OBJECTIVES@#Male hypogonadism is a condition where the body does not produce enough testosterone and significantly impacts health. Age, obesity, genetics, and oxidative stress are some physiological factors that may contribute to testosterone deficiency.Previous studies have shown many pharmacological benefits of Schisandra chinensis (S. chinensis) Baillon as an anti-inflammatory and antioxidant. However, the molecular mechanism of attenuating hypogonadism is yet to be well established. This research was undertaken to study the effects of S. chinensis extract (SCE) on testosterone deficiency.MATERIALS/METHODS: S. chinensis fruit was pulverized and extracted using 60% aqueous ethanol. HPLC analysis was performed to analyze and quantify the lignans of the SCE. @*RESULTS@#The 2,2-diphenyl-2-picrylhydrazyl and 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) scavenging assays confirmed that the SCE and its major lignans (schisandrol A and gomisin N) inhibit oxidative stress. Effects of SCE analysis on the testosterone level under oxidative stress conditions revealed that both schisandrol A and gomisin N were able to recover the lowered testosterone levels. Through mRNA expression of TM3 Leydig cell, we observed that the SCE lignans were able to induce the enzymes involved in testosterone biosynthesis-related genes such as 3β-HSD4 (P < 0.01 for SCE, and P < 0.001 for schisandrol A and gomisin N), 17β-HSD3 (P < 0.001 for SCE, schisandrol A and gomisin N), and 17, 20-desmolase (P < 0.01 for schisandrol A, and P < 0.001 for SCE and gomisin N). @*CONCLUSIONS@#These results support that SCE and its active components could be potential therapeutic agents for regulating and increasing testosterone production.

The Phonetic Characteristics in Patients of Bilateral Vocal Fold Paralysis Without Tracheotomy

OBJECTIVES: Patients with bilateral vocal fold paralysis (BVFP) theoretically have difficulty producing voiceless consonants. However, perceptual studies have revealed clear production of voiceless consonants with good articulation scores in nontracheostomized patients. The purpose of this study was to clarify the production of voiceless stops during articulation in patients with BVFP compared to normal speakers. METHODS: The perceptual, acoustic, and aerodynamic characteristics of patients with BVFP and those with normal speech were investigated with special reference to voiceless stop consonants. Test words were prepared to place the stop consonants in different phonological environments, and were all nonsense words. RESULTS: The patients with BVFP perceptually produced the three types of stops successfully. However, they acoustically varied voice onset time to produce phonetically representative stops but decreased voice onset time of /ph/ and /p/ compared to those of normal speakers. These patients may properly control air pressure to produce the three types of stop consonants similar to normal speakers. CONCLUSION: The patients with BVFP realized the distinctions between the three types of stops similar to the normal speakers. Although vocal mobility was absent in the patients with BVFP, voice onset time, vowel duration, closure duration, and air pressure were similar to those of normal speakers.

Changes in Oral Vowel Sounds and Hyoid Bone Movement After Thyroidectomy

OBJECTIVES: Voice and speech alterations after total thyroidectomy may be associated with other extralaryngeal factors, such as neck muscle dysfunction and neck scar contracture. We evaluated the acoustic characteristics of oral vowel sounds and changes in hyoid bone movement before and after thyroidectomy. METHODS: Twenty-nine female patients undergoing total thyroidectomy were included. Fundamental frequencies (Fo), formants and vowel space areas were evaluated before surgery and 7 days and 3 months after surgery to acoustically analyze the oral vowel sounds. Videofluoroscopic images were taken at the same times to evaluate hyoid bone movement. RESULTS: The Fo levels of seven vowels decreased significantly after surgery. The vowel formant changes the F1 of vowel /[e]/ decreased significantly from baseline at 3 months postoperatively, and the F3 of vowel /[i]/ decreased significantly from baseline 7 days postoperatively. The change in the vowel space area was not observed. The Y coordinate of the vowels /[i]/ and /[e]/ decreased significantly from baseline 7 days postoperatively due to changes in hyoid movement. CONCLUSION: The damage to the neck muscles after thyroidectomy changes in Fo, formant and hyoid bone position. These quantitative results could be used as basic data for voice management in patients who undergo thyroidectomy.

Sonographic Index for Extrathyroidal Extension of Papillary Thyroid Carcinoma / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Ultrasonography is the most useful tool for detecting extrathyroidal extension, which is the deciding factor in surgical extension of papillary thyroid carcinoma. However, there are few studies on pre-operative ultrasonographic findings about extrathyroidal extension. This research thus evaluates a predictive sonographic index of extrathyroidal extension. SUBJECTS AND METHOD: 265 patients with papillary thyroid carcinoma who underwent preoperative sonography and surgery were respectively reviewed. Sonographic findings were compared with pathological results. RESULTS: There were no differences among the patents in terms of calcification and echo texture, whereas significant differences were observed in terms of mass size, lymph node metastasis, capsule contact, and degree of capsule contact. These four factors were weighted according to the degree of severity and defined the extrathyroidal index as the total of these scores. The index had high sensitivity, specificity and predictability. CONCLUSION: We suggest that the extrathyroidal extension index with sonography is helpful for drawing pre-operative sonographic diagnosis.

The dose of cyclophosphamide for treating paraquat-induced rat lung injury

BACKGROUND/AIMS: Cyclophosphamide (CP) is a promising treatment for severe cases of paraquat (PQ) poisoning. We investigated the effective dose of CP for mitigating PQ-induced lung injury. METHODS: Adult male Sprague-Dawley rats were allocated into five groups: control, PQ (35 mg/kg, intraperitoneal injection), and PQ + CP (1.5, 15, or 30 mg/kg). The dimensions of lung lesions were determined using X-ray microtomography (micro-CT), and histological changes and cytokine levels were recorded. RESULTS: The micro-CT results showed that 15 mg/kg CP was more effective than 1.5 mg/kg CP for treating PQ-induced lung injury. At a dose of 1.5 mg/kg, CP alleviated the histological evidence of inflammation and altered superoxide dismutase activity. Using 15 mg/kg CP reduced the elevated catalase activity and serum transforming growth factor (TGF)-beta1 level. CONCLUSIONS: A CP dose of > 15 mg/kg is effective for reducing the severity of PQ-induced lung injury as determined by histological and micro-CT tissue examination, possibly by modulating antioxidant enzyme and TGF-beta1 levels.

A Case of Takotsubo Cardiomyopathy due to Submucosal Epinephrine Injection during Endoscopic Sinus Surgery / 대한이비인후과학회지

Epinephrine is widely used for hemostasis during endoscopic sinus surgery performed under local and general anesthesia. However, topical epinephrine can cause many adverse effects, such as hypertension, ventricular tachycardia, pulmonary edema and cardiac arrest. Takotsubo cardiomyopathy is a newly described clinical entity characterized by transient left ventricular dysfunction and no significant coronary artery stenosis. We experienced a rare case of reversible Takotsubo cardiomyopathy in a 56-year-old male after submucosal epinephrine injection with an appropriate dose during an endoscopic sinus surgery.

Benign Paroxysmal Positional Vertigo After Cochlear Implantation / 대한평형의학회지

Cochlear implantation (CI) has enabled hearing rehabilitation of patients with severe hearing impairment for more than 20 years now. There have been reported that one possible complication of CI is the impairment of balance function with resulting vertigo symptoms. CI still implies trauma on the labyrinthine structures to allow the electrode system to be inserted into the cochlear turns. Benign paroxysmal positional vertigo is an uncommon development after CI. We experienced an 80-year-old woman who had immediate onset of vertigo after CI, which diagnosed in postoperative one day after CI. In postoperative videonystagmography, no spontaneous nystagmus was observed, but in right Dix-Hallpike, torsional nystagmus, where the top of the eye rotates towards the right ear in beating fashion. Vertigo improved after modified Epley maneuver. However there was one recurrence after 12 days later. The case is described along with a review of the literature.

A Case of Nasopharyngeal Papillary Adenocarcinoma: Nasal Endoscopic Approach / 대한이비인후과학회지

Low-grade nasopharyngeal papillary adenocarcinoma is an unusual nasopharyngeal tumor. This malignant tumor originates in the epithelium and exhibits adenocarcinomatous differentiation and indolent behavior. Macroscopically, these tumors are pedunculated polypoid masses that arise on the roof of the nasopharynx. Microscopically, they are characterized by papillary and glandular epithelial proliferation. We report a case of a 25-year-old woman who presented with a papillary adenocarcinoma on the roof of nasopharynx; in describing the case, we have focused on the histological features and endoscopic management of the tumor. The tumor was completely excised via nasal endoscopic approach. Immunohistochemical analysis of the tumor was performed based on a differential diagnosis of metastatic papillary thyroid carcinoma. The testing involved thyroid transcription factor-1, thyroglobulin, and epithelial membrane antigen analysis. The patient remained disease-free for over 6 months after the surgical excision performed via nasal endoscopic approach.

Expression of OD314 during ameloblast differentiation and maturation / 대한치과보존학회지

Ameloblasts are responsible for the formation and maintenance of enamel which is an epithelially derived protective covering for teeth. Ameloblast differentiation is controlled by sequential epithelial-mesenchymal interactions. However, little is known about the differentiation and maturation mechanisms. OD314 was firstly identified from odontoblasts by subtraction between odontoblast/pulp cells and osteoblast/dental papilla cells, even though OD314 protein was also expressed in ameloblast during tooth formation. In this study, to better understand the biological function of OD314 during amelogenesis, we examined expression of the OD314 mRNA and protein in various stages of ameloblast differentiation using in-situ hybridization and immunohistochemistry. The results were as follows : 1. The ameloblast showed 4 main morphological and functional stages referred to as the presecretory, secretory, smooth-ended, and ruffle-ended. 2. OD314 mRNA was expressed in secretory ameloblast and increased according to the maturation of the cells. 3. OD314 protein was not expressed in presecretory ameloblast but expressed in secretory ameloblast and maturative ameloblast. OD314 protein was distributed in entire cytoplasm of secretory ameloblast. However, OD314 was localized at the proxiamal and distal portion of the cytoplasm of smooth-ended and ruffle-ended ameloblast. These results suggest that OD314 may play important roles in the ameloblast differentiation and maturation.