In-Kyo Chung

Amphiphilic effects of local anesthetics on rotational mobility in neuronal and model membranes

To provide a basis for studying the molecular mechanism of pharmacological action of local anesthetics, we carried out a study of the membrane actions of tetracaine, bupivacaine, lidocaine, prilocaine and procaine. Fluorescence polarization of 12-(9-anthroyloxy)stearic acid (12-AS) and 2-(9-anthroyloxy)stearic acid (2-AS) were used to examine the effects of local anesthetics on differential rotational mobility between polar region and hydrocarbon interior of synaptosomal plasma membrane vesicles (SPMV) isolated from bovine cerebral cortex, and liposomes of total lipids (SPMVTL) and phospholipids (SPMVPL) extracted from the SPMV. The two membrane components differed with respect to 2 and 12 anthroyloxy stearate (2-AS, 12-AS) probes, indicating that a difference in the membrane fluidity may be present. In a dose-dependent manner, tetracaine, bupivacaine, lidocaine, prilocaine and procaine decreased anisotropy of 12-AS in the hydrocarbon interior of the SPMV, SPMVTL and SPMVPL, but tetracaine, bupivacaine, lidocaine and prilocaine increased anisotropy of 2-AS in the membrane interface. These results indicate that local anesthetics have significant disordering effects on hydrocarbon interior of the SPMV, SPMVTL and SPMVPL, but have significant ordering effects on the membrane interface, and thus they could affect the transport of Na(+) and K(+) in nerve membranes, leading to anesthetic action.

Comparison of several procedures for the preparation of synaptosomal plasma membrane vesicles

Synaptosomal plasma membrane vesicles (SPMV) were isolated from fresh bovine cerebral cortex by several well-known procedures, and the best procedure was selected by enzymatic and morphological standards. The SPMV isolated by the modified procedure of Smith and Loh showed the highest purity. The specific activities of Na, K-ATPase, acetylcholinesterase and 5′-nucleotidase were about 5.6-fold, 2.5-fold and 3.3-fold, respetively, enriched in the plasma membrane fraction as compared to those of the crude homogenate. Electron microscopic examination also showed that the membranes were in vesicular form.

A comparative study of the effectiveness of sinus bone grafting with recombinant human bone morphogenetic protein 2–coated tricalcium phosphate and platelet-rich fibrin–mixed tricalcium phosphate in rabbits

OBJECTIVES The objective of this histologic study was to evaluate platelet-rich fibrin (PRF)-mixed tricalcium phosphate (TCP) and recombinant human bone morphogenic protein 2 (rhBMP-2)-coated TCP in their potential to enhance bone regeneration in sinus elevation in rabbits as well as in their inflammatory features. STUDY DESIGN Bilateral round-shaped defects (diameter 8.0 mm) were formed in the maxillary anterior sinus walls of 36 New Zealand white rabbits. The defects were grafted with TCP only (control group), with rhBMP-2-coated TCP (experimental group A) and with PRF-mixed TCP (experimental group B). Each group included 12 rabbits. The animals were killed at 3 days, 1 week, 2 weeks, 4 weeks, 6 weeks, and 8 weeks. The specimens underwent decalcification and were stained for histologic analysis. RESULTS There were no significant differences in inflammatory features among the groups at 3 days or the first week after operation. In a histomorphometric analysis, the new bone formation ratio showed significant differentiation between groups A and B. The TCP-only control group showed a relatively lower bone formation ratio rather than the experimental groups. The PRF-mixed TCP group showed a larger bone formation area, compared with both the control group and group A. CONCLUSIONS In the results of the histologic evaluation (hematoxylin-eosin, Masson trichrome stain), the experimental groups A and B showed rapid bone formation, remodeling, and calcification in the second week. Moreover, there was a significant difference between those experimental groups and the control group in the new bone formation area at the fourth, sixth, and eighth weeks. The PRF-mixed TCP showed more rapid bone healing than the rhBMP-2-coated TCP or the TCP-only control.

The impact factors on 5-year survival rate in patients operated with oral cancer

Objectives The purpose of this study is to analyze clinical impact factors on the survival rate, and to acquire basic clinical data for the diagnosis of oral cancer, for a determination of the treatment plan with long-term survival in oral cancer patients. Materials and Methods Through a retrospective review of the medical records, the factors for long-term survival rate were analyzed. Thirty-seven patients, among patient database with oral cancer treated in the Department of Oral and Maxillofacial Surgery at Pusan National University Hospital within a period from March 1998 to March 2008, were selected within the study criteria and were followed-up for more than 5 years. The analyzed factors were gender, age, drinking, smoking, primary tumor site, type of cancer, TNM stage, recurrence of affected region, and metastasis of cervical lymph node. The 5-year survival rate on the impact factors was calculated statistically using the Kaplan-Meier method. Results By classification of clinical TNM at the 1st visit, there were 11 (29.7%) cases for stage I, 11 (29.7%) cases for stage II, 3 (8.1%) cases for stage III, and 12 (32.5%) cases for stage IV. The 5-year survival rate of total oral cancer patients after the operation were 75.7%, pathological TNM stage related 5-year survival rate were as follows: stage I 90.0%, stage II 81.8%, stage III 100% and stage IV 45.5%; in which the survival rate difference by each stage was significantly observed. The recurrence of cervical lymph node was the significant impact factor for the survival rate, because only 30.0% the survival rate in recurrent cases existed. During the follow-up, there were 15 (40.5%) patients with confirmed recurrence, and the 5-year survival rate of these patients was decreased as 46.7%. Conclusion The classification of clinical and pathological TNM stage, local recurrence after surgery, and metastasis of cervical lymph node after surgery were analyzed as the 3 most significant factors.

Facial Bone Fracture Patients Visiting Pusan National University Hospital in Busan and Yangsan: Trends and Risks

Purpose: This study examined patients with facial bone fracture visiting Pusan National University Dental Hospital to understand the trends, and to enhance appropriate care and treatment for patients with facial bone fracture. Methods: We investigated 531 patients presenting with facial bone fracture in Yangsan and 802 patients in Busan from January 2010 to December 2013. We divided the patients by year, month, gender, age, site, and cause to compare with historic data and other studies. Results: The gender ratio was 3.58:1 in Yangsan and 4.31:1 in Busan. Patients aged in their 20s had the highest number of facial bone fractures in both Yangsan and Busan. The most frequent fracture site was the mandible, and the most frequent cause was slip down in both Yangsan and Busan. Conclusion: The investigation and comparison of patients with facial bone fracture who visited Pusan National University Hospital located at Yangsan and Busan from 2010 to 2013 found a difference in the total number of patients at each hospital, but the trends were not significantly different.

Resveratrol Induces Mitochondrial Apoptosis and Inhibits Epithelial-Mesenchymal Transition in Oral Squamous Cell Carcinoma Cells

ABSTRACT OSCC is the most common malignant cancer of the head and neck. EMT is an essential cellular process critical to the morphogenesis and homeostasis of solid tissues. It is also involved in the initial stage of cancer metastasis and invasion in which cells lose epithelial characteristics. While cancer therapy protocols such as surgery, radiation, and chemotherapy are effective and useful, the drug tolerance and toxicity of OSCC patients remain a problem. Resveratrol is mainly produced in red grape skin and exhibits anti-oxidative, anti-inflammatory, anti-proliferative, and anti-cancer properties. This study was undertaken to investigate the underlying mechanisms giving rise to the induction of apoptosis by resveratrol in the human tongue squamous cell carcinoma cell line. Resveratrol treatment resulted in a time- and dose-dependent decrease in cell viability and increased the apoptotic cell ratio in CAL-27, SCC15, and SCC25 cells. Resveratrol treatment of CAL-27 cells showed that several lines of apoptotic manifestation and decreased cell migration, invasion, and EMT-inducing transcription factor. Taken together, our findings demonstrate the inhibitory effect of resveratrol in human OSCC cells via the mitochondrial pathway and that resveratrol is able to inhibit cell invasion and migration by inhibiting the EMT-inducing transcription factors.

Transient ipsilateral mydriasis during correction of left blowout fracture.

Mydriasis, either bilateral or unilateral, seldom occurs during reconstruction of periorbital fracture. Anisocoria, a unilateral mydriasis, requires more urgent assessment than bilateral mydriasis does. Pharmacologic agents, local anesthetic infiltration, as well as direct or indirect oculomotor nerve damage are possible causes of unilateral mydriasis. Few cases have been reported about intraoperative temporary ipsilateral mydriasis during correction of blowout fracture. We have experienced an unusual case of anisocoria and report the case with literature reviews.

Effects of dimyristoylphosphatidylethanol and ethanol on thickness of neuronal membrane lipid bilayers

The aim of this study was to provide a basis for examining the molecular mechanism for the pharmacological action of ethanol. Energy transfer between the surface fluorescent probe 1-anilinonaphthalene-8-sulfonic acid and hydrophobic fluorescent probe 1,3-di(1-pyrenyl)propane was used to examine the effect of both dimyristoylphosphatidylethanol (DMPEt) and ethanol on the thickness (D) of the synaptosomal plasma membrane vesicles (SPMV) isolated from the bovine cerebral cortex. The thickness (D) of the intact SPMV was 1.044 ± 0.008 (arbitrary units, n=5) at 37°C (pH 7.4). Both DMPEt and ethanol decreased the thickness of the SPMV lipid bilayer in a dose-dependent manner with a significant decrease in thickness observed at 5 µM and 25 mM, respectively. It was assumed that both ethanol and DMPEt cause interdigitation in the SPMV lipid bilayers. The effects of ethanol on the neuronal membranes were attributed to its direct and indirect actions. The indirect action of ethanol refers to the action of phosphatidylethanol, which is an ethanol abnormal metabolite, on the neuronal membranes. The decrease in membrane thickness by both DMPEt and ethanol might be responsible for some, but not all of its anesthetic actions.

Effects of n-Alkanols on the lateral diffusion of total phospholipid fraction extracted from brain membranes

We investigated the effects ofn-alkanols on the range and rate of the lateral diffusion of 1,3-di(1-pyrenyl)propane in the model membranes of total phospholipid fraction extracted from synaptosomal plasma membrane vesicles. n-Alkanols increased the range and rate of the lateral diffusion of 1,3-di(1-pyrenyl)propane in the bulk model membrane structures (inner+outer monolayers) and the potencies ofn-alkanols up to 1-nonanol increased by 1 order of magnitude as the carbon chain length increases by two carbon atoms. The cut-off phenomenon was reached at 1-decanol, where further increase in hydrocarbon length resulted in a decrease in the lateral diffusion. However, significant changes in the l′/l value were not observed by methanol (from 100 to 2500 mM), ethanol (from 25 to 800 mM), and 1-propanol (from 10 to 250 mM) over entire concentration.

The Effect of Methanol on the Structural Parameters of Neuronal Membrane Lipid Bilayers

The structures of the intact synaptosomal plasma membrane vesicles (SPMVs) isolated from bovine cerebral cortexs, and the outer and the inner monolayer separately, were evaluated with 1,6-diphenyl-1,3,5-hexatriene (DPH) and 1,3-di(1-pyrenyl)propane (Py-3-Py) as fluorescent reporters and trinitrophenyl groups as quenching agents. The methanol increased bulk rotational and lateral mobilities of SPMVs lipid bilayers. The methanol increased the rotational and lateral mobilities of the outer monolayers more than of the inner monolayers. n-(9-Anthroyloxy)stearic acid (n-AS) were used to evaluate the effect of the methanol on the rotational mobility at the 16, 12, 9, 6, and 2 position of aliphatic chains present in phospholipids of the SPMVs outer monolayers. The methanol decreased the anisotropy of the 16-(9-anthroyloxy)palmitic acid (16-AP), 12-(9-anthroyloxy)stearic acid (12-AS), 9-(9-anthroyloxy)stearic acid (9-AS), and 6-(9-anthroyloxy)stearic acid (6-AS) in the SPMVs outer monolayer but it increased the anisotropy of 2-(9-anthroyloxy)stearic acid (2-AS) in the monolayers. The magnitude of the increased rotational mobility by the methanol was in the order at the position of 16, 12, 9, and 6 of aliphatic chains in phospholipids of the outer monolayers. Furthermore, the methanol increased annular lipid fluidity and also caused membrane proteins to cluster. The important finding is that was far greater increase by methanol in annular lipid fluidity than increase in lateral and rotational mobilities by the methanol. Methanol alters the stereo or dynamics of the proteins in the lipid bilayers by combining with lipids, especially with the annular lipids. In conclusion, the present data suggest that methanol, in additions to its direct interaction with proteins, concurrently interacts with membrane lipids, fluidizing the membrane, and thus inducing conformational changes of proteins known to be intimately associated with membranes lipids.