Modeling Long-term Spike Frequency Adaptation in SA-I Afferent Neurons Using an Izhikevich-based Biological Neuron Model

To develop a biomimetic artificial tactile sensing system capable of detecting sustained mechanical touch, we propose a novel biological neuron model (BNM) for slowly adapting type I (SA-I) afferent neurons. The proposed BNM is designed by modifying the Izhikevich model to incorporate long-term spike frequency adaptation. Adjusting the parameters renders the Izhikevich model describing various neuronal firing patterns. We also search for optimal parameter values for the proposed BNM to describe firing patterns of biological SA-I afferent neurons in response to sustained pressure longer than 1-second. We obtain the firing data of SA-I afferent neurons for six different mechanical pressure ranging from 0.1 mN to 300 mN from the ex-vivo experiment on SA-I afferent neurons in rodents. Upon finding the optimal parameters, we generate spike trains using the proposed BNM and compare the resulting spike trains to those of biological SA-I afferent neurons using the spike distance metrics. We verify that the proposed BNM can generate spike trains showing long-term adaptation, which is not achievable by other conventional models. Our new model may offer an essential function to artificial tactile sensing technology to perceive sustained mechanical touch.

The Effects of the FIFA 11+ and Self-Myofascial Release Complex Training on Injury, Flexibility and Muscle Stiffness of High School Football Players

Purpose@#The purpose of this study was to investigate the effects of complex training on injury, flexibility, and muscle stiffness in high school male football players. @*Methods@#A total of 60 football players were included in the study and were divided into three groups viz. the complex training group (CTG), 11+ training group (11 + TG), and traditional training group (TTG). Injuries were recorded based on the prospective investigation method after starting the study, and the flexibility and muscle stiffness of the subjects were evaluated. @*Results@#The research results showed that the injury rate per match was significantly lower in the CTG and 11 + TG than the TTG. In the CTG, the flexibility of the hamstrings significantly increased and the stiffness of the rectus femoris (RF), biceps femoris (BF), and tensor fascia latae (TFL) muscles significantly decreased (p < 0.05). In the 11 + TG, the stiffness of the RF significantly decreased (p < 0.05). In the TTG, the flexibility of the hamstrings significantly increased (p < 0.05). Hamstring flexibility showed a significantly higher increase in the CTG and TTG compared to the 11 + TG (p < 0.05). Also, the stiffness of the RF and TFL muscles showed a significantly higher decrease in the CTG compared to the 11 + TG and TTG (p < 0.05). The stiffness of the BF muscles too showed a more significant decrease in the CTG compared to the TTG (p < 0.05). @*Conclusion@#The complex training method of the Fédération International de Football Association (FIFA) 11+ and self-myofascial release (SMFR) as a warm-up program, prevent injuries, enhance flexibility, and lower muscle stiffness of football players in high school. Thus, it is necessary to ensure the widespread use of the complex training program by instructors and players under the supervision of the Korea Football Association (KFA), given its reliability in preventing injuries and improving the performance of football players.

Influence of Slashpipe Exercise on Symmetrical Contraction of Trunk Muscle in Normal Adults

PURPOSE: This study examined the effects of slashpipe exercise on reducing the thickness of the left and right external oblique, internal oblique, transverse abdominis, erector spinae, and multifidus muscles.METHODS: A total of 29 healthy adult men and women were included in the study. They performed trunk flexion in the supine position and trunk extension in the prone position with a slashpipe and weight bar. The external oblique, internal oblique, and transverse abdominis muscles were measured in the supine position, while the erector spinae and multifidus muscles were measured in the prone position. The data were analyzed using the SPSS ver 21.0 statistical program. The difference in thickness between the right and left sides of the trunk muscle was analyzed by repeated measures analysis. The statistical significance level was set to p<0.05.RESULTS: The results showed that the slashpipe exercise reduced significantly the difference in thickness of the oblique internus and erector spinae muscles compared to the weight bar exercise.CONCLUSION: The chaotic fluidity of the fluid filled inside the slashpipe could be used as sensory feedback information on body mal-alignment, which would have positively affected the symmetrical contraction of the trunk muscles as a trigger for self-correction. Therefore, it will have a useful effect not only on the health of the general public, but also on low back patients and athletes with muscle asymmetry.

Acute coronary artery obstruction after aortic valve replacement surgery and role of transesophageal echocardiography

Acute coronary artery obstruction is a rare but fatal complication of surgical aortic valve replacement (AVR). Sudden coronary spasm, embolization of calcium plaque, and surgical factors can induce acute coronary syndrome after AVR. Here, we report a case of left main coronary ostial obstruction that occurred immediately after weaning from cardiopulmonary bypass. This case highlights the importance of coronary ostial flow patency and assessment of regional wall motion abnormalities with intraoperative transesophageal echocardiography in AVR.

Acute coronary artery obstruction after aortic valve replacement surgery and role of transesophageal echocardiography

Acute coronary artery obstruction is a rare but fatal complication of surgical aortic valve replacement (AVR). Sudden coronary spasm, embolization of calcium plaque, and surgical factors can induce acute coronary syndrome after AVR. Here, we report a case of left main coronary ostial obstruction that occurred immediately after weaning from cardiopulmonary bypass. This case highlights the importance of coronary ostial flow patency and assessment of regional wall motion abnormalities with intraoperative transesophageal echocardiography in AVR.

Kinematic Analysis of Lower Extremity Joint Movements during Sidestep at Different Sidestep Speeds / 대한스포츠의학회지

The purpose of this study were to examine the effects of the speed of sidestep in a specific direction on the kinematic variables of the lower extremities and to provide basic information on sidestep. The subjects of this study were eight students at Hanseo University who did not have a problem in lower extremity alignment. Biomechanical data were collected using a motion analysis system and force plate and Kruskal-Wallis test was performed in order to test differences according to speed. The results of this study were as follow. First, as to hip joint angle according to speed, when the speed increased, in the sagittal view, the maximum flexion angle decreased, the range of motion (ROM) decreased, and the flexion angle at the highest ground reaction force decreased, and in the transverse view, the internal rotation angle at the highest ground reaction force increased. Second, as to knee joint angle according to speed, when the speed increased, in the sagittal view, the maximum flexion angle decreased, the ROM decreased, and the flexion angle at the highest ground reaction force decreased, and in the coronal view, the maximum varus angle decreased, and the ROM decreased. Third, as to ankle joint angle according to speed, when the speed increased, in the sagittal view, the ROM decreased, and the dorsiflexion angle at the highest ground reaction force decreased, and in the coronal view, the minimum inversion angle increased. This suggests that high-speed sidestep during a game increases the risk of injury and degenerative arthritis among athletes.

A Preliminary Study on Musculoskeletal Pain in K-League Referees: A Complete Survey / 대한스포츠의학회지

The environment around working process of the referees during matches will burden him or her physically by doing specific actions frequently and give negative effects on musculoskeletal system. In order to find out musculoskeletal pain has occurred on specific muscles, surveys have been taken by 44 referees in K-league for this thesis. We evaluated the differences between referee and assistant referee. Fourteen (87.5%) referees and twenty-four (89.3%) assistant referees stated that they had one musculoskeletal pain. For referees, 43.8% had hamstring pains, 31.3% had calf muscle pains, and 25% had low back pains. For assistant referees, 39.3% felt knee pains, 32.1% had adductors pains, 28.5% felt calf muscle pains. Therefore, with the data analysis by dividing their roles, both groups had similar effect on hamstring and knee joint. For the question asking for the personal reasons of the pains were 61.4% of 'Carelessness of physical fitness', 47.7% of 'repetition of certain actions', and 43.2% of 'lack of treatment after being damaged'. Also, in order to prevent pain, the referees answered that they train personally (40.9%), rest appropriately (20.5%), and go to hospital for treatment (18.2%). After receiving the result of this study, training programs and education are needed to prevent pain. Moreover, on the next study, fundamental causes of the pains should be found by using history taking, physical examination, medical and scientific machines in order to analyze the movements of the referees' human dynamics.

The Influence of the Devotion Movement on the Health Care in North Korea / 의사학

Since the early 1960s, North Korea has conducted 'devotion movement' under the directorship of Kim Il Sung across the nation. As a matter of fact, the movement was not a novel invention at all. When North Korean Temporary People's Polity was established in 1946, North Korea emphasized the importance of the devoted care of health personnel. It meant to reform the people's thought and mind along with complementing the lack of human and material resources. Thought reform was not a peculiar phenomenon observed in North Korea only. It was particularly stressed out among communist countries, including the Soviet Union. However any other communist country stresses the importance of thought reform. Devotion movement should be viewed as part of this process. As shown in many cases, the extent and degree of devotion movement and care are beyond our imagination, which does not intend to mean that North Korean health personnel's attitude towards patients is superior to the counterparts in South Korea. Indeed human being's behavior cannot be understood without taking account of society in general. The question can be raised as to whether or not North Korean health personnel's devoted care is really voluntary. To put aside the testimony that the most powerless group in a society can fall prey to victims, if social environment, whether directly or indirectly, is action on the people's thought and mind even in a subtle way and thus influence one's decision power, it is hard to highly evaluate the devoted care in North Korea. Moreover it seems like that the internal conflict exists surrounding devotion. In conclusion, I think that North Korean devotion movement has enforced health personnel to reform their thought and mind to adapt to North Korean regime and has played an important role to accomplish the purpose of North Korean Labor Party to realize essential constituents of its health system, in such a situation in which essential medical supplies are severely lacking. But it seems like that it plays reverse action to develope sound North Korean health system.

A Case of RUL Bronchopleural Fistula Occluded by Flexible Bronchoscope with Endobronchial Watanabe Spigot (EWS) / 결핵및호흡기질환

An 86 year old woman was admitted complaining of dyspnea and right pleuritic pain with a 5 week durations. A physical examination, chest X-ray, and diagnostic thoracentesis upon admission revealed findings consistent with severe pneumonia and empyema on the right lung. Despite the insertion of a chest tube and negative suction via Emersion pump, the continuous air leakage was sustained, and a bronchopleural fistula (BPF) was found on the chest-CT. A flexible bronchoscopic occlusion with an Endobronchial Watanabe Spigot (EWS) was performed after 56 days of admission. An 5 mm diameter EWS was successfully inserted into the anterior segmental bronchus of the right upper lobe by flexible bronchoscope. There was no aAir leakage detected after this procedure. The patient was discharged 30 days after the EWS occlusion.

Oxidative Inactivation of Peroxiredoxin Isoforms by H2O2 in Pulmonary Epithelial, Macrophage, and other Cell Lines with their Subsequent Regeneration / 결핵및호흡기질환

BACKGROUND: Peroxiredoxins (Prxs) are a relatively newly recognized, novel family of peroxidases that reduce H2O2 and alkylhydroperoxide into water and alcohol, respectively. There are 6 known isoforms of Prxs present in human cells. Normally, Prxs exist in a head-to-tail homodimeric state in a reduced form. However, in the presence of excess H2O2, it can be oxidized on its catalytically active cysteine site into inactive oxidized forms. This study surveyed the types of the Prx isoforms present in the pulmonary epithelial, macrophage, endothelial, and other cell lines and observed their response to oxidative stress. METHODS: This study examined the effect of exogenous, excess H2O2 on the Prxs of established cell lines originating from the pulmonary epithelium, macrophages, and other cell lines, which are known to be exposed to high oxygen partial pressures or are believed to be subject to frequent oxidative stress, using non-reducing SDS polyacrylamide electrophoresis (PAGE) and 2 dimensional electrophoresis. RESULT: The addition of excess H2O2 to the culture media of the various cell-lines caused the immediate inactivation of Prxs, as evidenced by their inability to form dimers by a disulfide cross linkage. This was detected as a subsequent shift to its monomeric forms on the non-reducing SDS PAGE. These findings were further confirmed by 2 dimensional electrophoresis and immunoblot analysis by a shift toward a more acidic isoelectric point (pI). However, the subsequent reappearance of the dimeric Prxs with a comparable, corresponding decrease in the monomeric bands was noted on the non-reducing SDS PAGE as early as 30 minutes after the H2O2 treatment suggesting regeneration after oxidation. The regenerated dimers can again be converted to the inactivated form by a repeated H2O2 treatment, indicating that the protein is still catalytically active. The recovery of Prxs to the original dimeric state was not inhibited by a pre-treatment with cycloheximide, nor by a pretreatment with inhibitors of protein synthesis, which suggests that the reappearance of dimers occurs via a regeneration process rather than via the de novo synthesis of the active protein. CONCLUSION: The cells, in general, appeared to be equipped with an established system for regenerating inactivated Prxs, and this system may function as a molecular "on-off switch" in various oxidative signal transduction processes. The same mechanisms might applicable other proteins associated with signal transduction where the active catalytic site cysteines exist.

Expression of Peroxiredoxin and Thioredoxin in Human Lung Cancer and Paired Normal Lung / 결핵및호흡기질환

BACKGROUND: Continuous growth stimulation by various factors, as well as chronic oxidative stress, may co-exist in many solid tumors, such as lung cancer. A new family of antioxidant proteins, the peroxiredoxins (Prxs), have been implicated in the regulation of many cellular processes, including cell proliferation, differentiation and apoptosis. However, a real pathophysiological significance of Prx proteins, especially in lung disease, has not been sufficiently defined. Therefore, this study was conducted to investigate the distribution and expression of various Prx isoforms in lung cancer and other pulmonary conditions. METHOD: Patients diagnosed with lung cancer, and who underwent surgery at the Ajou Medical Center, were enrolled. The expressions of Prxs, Thioredoxin (Trx) and Thioredoxin reductase (TR) were analyzed using proteomic techniques and the subcellular localization of Prx proteins was studied using immunohistochemistry on normal mouse lung tissue. RESULT: Immunohistochemical staining has shown the isoforms of Prx I, II, III and V are predominantly expressed in bronchial and alveolar lining epithelia, as well as in the alveolar macrophages of the normal mouse lung. The isoforms of Prx I and III, and thioredoxin were also found to be over-expressed in the lung cancer tissues compared to their paired normal lung controls. There was also an increased amount of the oxidized form of Prx I, as well as a putative truncated form of Prx III, in the lung cancer samples when analyzed using 2-dimensional electrophoresis. In addition, a 43 kDa intermediate molecular weight protein band, and other high molecular weight bands of over 20 kDa, recognized by the anti-Prx I antibody, were present in the tissue extracts of lung cancer patients on 1-Dimensional electrophoresis, which require further investigation. CONCLUSION: The over-expressions of Prx I and III, and Trx in human lung cancer tissue, as well as their possible chaperoning function, may represent an attempt by tumor cells to adjust to their microenvironment in a manner advantageous to their survival and proliferation, while maintaining their malignant potential.

Pseudophakic Residual Astigmatism

We investigated pseudophakic residual astigmatism in order to minimize postoperative refractive astigmatism. We examined 110 eyes of 87 patients who had undergone phacoemulsification with small incision and posterior chamber intraocular lens (IOL) implantation. Corneal astigmatism was measured using an autokeratometer (RK-5, canon), refractive astigmatism by manifest refraction, and residual astigmatism by vector analysis. Mean pseudophakic residual astigmatism was +0.47 X 176degrees, predominantly against-the-rule. Variations of pseudophakic residual astigmatism according to sex, age and IOL type were not statistically significant. When performing cataract surgery as refractive surgery, we may consider that pseudophakic residual astigmatism is approximately 0.50D against-the-rule.

A Case of Primary Signet Ring Cell Carcinoma of Lung with Multiple Bone Metastasis / 결핵및호흡기질환

Signet ring cell carcinoma of lung is an unique variant of mucin producing adenocarcinoma which is characterized by abundant intracellular mucin accumulation. Only a few cases of primary signet ring cell carcinoma of lung have been reported in the world wide literature. And we have, recently experienced one case of primary signet ring cell carcinoma of lung. A 55 years old man was evaluated for paralysis of lower extremities and was found to have lung cancer in the left upper and lower lobe with pleural, multiple spinal, bone and liver metastases. Signet ring tumor cells were revealed by cytologic examination of pleural fluids. And there were no evidence of signet ring cell carcinoma of other organs. Primary signet ring cell carcinoma of lung seems to have an aggressive behavior and therapeutic modalities could be different from those for signet ring cell carcinomas from other organs. Therefore it is important to separate primary signet ring cell adenocarcinoma of lung from metastatic tumors.

A Case of Nd: YAG Laser Injury to the Macula

PURPOSE: We report one case of macular injury by Nd: YAG laser during aiming of the laser beam. METHODS: A 34-year-old man injured his right eye accidentally while aiming a Nd: YAG laser. He was referred to our ophthalmologic department because of diminished vision in the right eye at 2 hours after the accident. Central scotoma was noted. Best corrected visual acuity was 0.02 in the right eye. On fundus examination there were preretinal hemorrhage on the fovea, a full thickness macular hole of 1/3 optic disc diameter, parafoveal retinal edema and vitreous hemorrhage on inferior fundus. Seven days after the accident, a star shaped subretinal fibrosis and scar formation were seen on fundus examination and fluorescein angiography showed star shaped hyperfluorescence area on the fovea. Three months after the accident preretinal and vitreous hemorrhage were resolved and the macular hole was closed spontaneously, but the subretinal scar and fibrosis progressed and best corrected visual acuity remained as 0.02 in the right eye. RESULTS: Visual acuity was severely decreased due to Nd: YAG laser injury to the macula.

Reuse of the Microkeratome Blade to Make a Consistent Corneal Flap in LASIK

PURPOSE: We evaluated the possibility of making a consistent corneal flap by reusing the microkeratome blade. METHODS: We performed LASIK surgery on 40 eyes of 26 patients by reusing the microkeratome blades which made the corneal flap thickness between 120 micrometer and 160 micrometer in the previous LASIK surgery. We selected 40 eyes of 25 patients with the same range of preoperative central corneal thickness, spherical equivalent, keratometry values, and astigmatism as a control group from the patients who had LASIK surgery with new microkeratome blades. We compared the mean and the deviation of the corneal flap thickness between the two groups. RESULTS: The mean central thickness of the corneal flap was 134.3 +/- 18.0 micrometer (range 89.6~161.7 micrometer) in the group using reused blades, and 134.4 +/- 24.6 micrometer (range 62.3~177.0 micrometer) in the control group. The mean deviation of the corneal flap thickness was 14.7 +/- 10.0 micrometer in the group using reused blades and 18.4 +/- 16.0 micrometer in the control group, and there was no significant difference between the two groups (p=0.218). CONCLUSIONS: The amount of deviation of corneal flap thickness was not decreased by reusing the microkeratome blade.

Long-term Intraocular Pressure Outcome after Successful Laser Iridotomy for the Acute Primary Angle-closure Glaucoma

PURPOSE: To evaluate the long-term outcome of intraocular pressure (IOP) after successful laser peripheral iridotomy in the eyes with acute primary angle-closure glaucoma. METHODS: Retrospective study of 45 eyes of 40 consecutive patients with acute primary angle-closure glaucoma was performed. After successful laser peripheral iridotomy, the subsequent long-term (at least 6 months) IOP outcome was analyzed. Re-elevation of IOP on follow-up was defined as IOP greater than 21 mmHg requiring medications or surgery. RESULTS: Thirty-two eyes (71.1%) of 45 eyes were successfully treated without additional treatment in the long-term follow-up. However, re-elevation of IOP developed in 13 eyes (28.9%) on follow-up, of which 5 eyes (11.1%) eventually underwent trabeculectomy. Sex and age of the patient, duration of acute symptoms and level of IOP were not the risk factors. CONCLUSIONS: Although the laser peripheral iridotomy has been known to be effective in initial treatment of acute primary angle-closure glaucoma, close monitoring of IOP is recommended in the long-term follow-up.

The Relationship between the Capillary Nonperfusion Area and the Retinal Nerve Fiber Layer Defects in Branch Retinal Vein Occlusion Patients

PURPOSE: To determine the relationship between the capillary nonperfusion area and the retinal nerve fiber layer (RNFL) defects in branch retinal vein occlusion (BRVO) patients. METHODS: We compared the difference between the RNFL thickness of both eyes in unilateral BRVO patients using the scanning laser polarimeter (GDx R ). The mean RNFL thickness was calculated for each quadrant. Fluorescein angiography was done to determine the retinal capillary nonperfusion area and we evaluated the relationship between the retinal capillary nonperfusion area and the right-left difference of RNFL thickness. RESULTS: In left superior temporal BRVO group, the Average of RNFL was thinner (p=0.015) and the Integral was smaller (p=0.045) in the left BRVO eye than in the right normal eye in the superior temporal sector. In patients with the other sector BRVO, there was no significant difference of RNFL thickness between both eyes. As the retinal capillary nonperfusion area increased, the right-left difference of Average increased in the superior temporal sector in patients with left superior temporal BRVO (p=0.042). CONCLUSIONS: The scanning laser polarimeter allowed the quantification of RNFL defect in patients with BRVO, and it may help to evaluate the quantification of retinal ischemia.

Clinical Significance of serum Endothelin-1 and Interleukin-8 in Sepsis / 결핵

BACKGROUND: Sepsis is a clinical syndrome characterized by a systemic inflammatory and hemodynamic response to severe bacterial infections that involve various mediators. Endothelin (ET)-1, a potent vasocon strictor is associated with multiple organ failure, and interleukin (IL)-8, a proinflammtory cytokine, plays a major role in neurophil activation. Both have been reported to be useful parameters in the clinical assessment of sepsis. The levels of ET-1 and IL-8 in the blood were measured in patients with sepsis, and the correlation of both parameters and their relationship with the clinical data was assessed. METHODS: 19 sepsis patients and 17 controls were studied. Blood samples of the sepsis patients were drawn in day 1, 3, 7, and 14. the APACHE III scores were calculated in concurrent days. The ET-1 and IL-8 levels were measured using immunoassay methods. RESULTS: The ET-1 levels of patients with sepsis were significantly higher than in the controls. In patients with sepsis, non-survivors had higher ET-1 levels than survivors on day 1 and 7, and patients with shock also had higher ET-1 levels than normotensive patients on admission. The ET-1 levels were significantly correlated wit the creatinine levels in day 1, 7, and 14. The IL-8 levels showed a significant correlation with the ET-1 levels on day 14. CONCLUSION: ET-1 was found to be closely related with the clinical outcome, shock, and renal failure, and showed a correlation with IL-8. these mediators can be considered not only to play pathophysiologic roles but also as useful parameters in the clinical assessment of sepsis.

A Case of Keratectasia 5 Years after Photorefractive Keratectomy

PURPOSE: The clinically evident keratectasia has not been reported after photorefractive keratectomy (PRK) on the eyes with normal preoperative corneal topography. Herein, we present a case of keratectasia developed 5 years after PRK. METHODS: A 20-year-old man underwent the PRK for correction of myopic astigmatism in 1993. Preoperative manifest refractions were -4.00 D-0.50 D x 90degrees in the right eye and -3.75 D-0.75 D x 85degrees in the left eye. Although pachymetry was not performed, preoperative examinations including corneal topography did not show any sign of early keratoconus or forme fruste keratoconus. The operations were uneventfully performed on two eyes at an interval of one month. RESULTS: Up to 9 months after PRK, the patient's uncorrected visual acuity had been maintained 1.2 in both eyes. When the patient returned 5 years after PRK, he complained of decreasing visual acuity (0.5)in his right eye. During the next 2 years, the vision of the right eye was deteriorated to 0.04, and could not be corrected with the spectacles. The corneal topography of the right eye revealed profound steepeningjust inferior to the corneal center, and he had become contact lens intolerant. The left eye remained stable. The central corneal thickness was 419.0 micrometerin the right eye and 476.3 micrometerin the left eye.

Cyclophosphamide: Induced lung toxicity in a patient with Wegener's granulomatosis / 대한내과학회지

Lung toxicity associated with cyclophosphamide use is a rare but serious side effect, that may result in a fatal course. However no such cases have been reported in Korea, so clinicians would not be alert to this adverse effect. We recently experienced a woman with Wegener's granulomatosis and idiopathic pulmonary fibrosis. This patient had been administered 12 grams of cyclophosphamide for 4 months. At that time of admission, She felt aggravating dyspnea on exertion for 2 weeks. Her chest x-ray and high resolution CT revealed aggravated reticular opacities and ground glass appearances. Dyspnea was improved and ground glass appearances on HRCT was disappeared after discontinuation of cyclophosphamide. We diagnosed this case as cyclophosphamide-induced pneumonitis and report it with a brief review of the literature.