• The Korean Journal of Physiology and Pharmacology
• /
• v.20 no.5
• /
• pp.547-556
• /
• 2016

Myometrial relaxation of mouse via expression of two-pore domain acid sensitive (TASK) channels was studied. In our previous report, we suggested that two-pore domain acid-sensing $K^+$ channels (TASK-2) might be one of the candidates for the regulation of uterine circular smooth muscles in mice. In this study, we tried to show the mechanisms of relaxation via TASK-2 channels in marine myometrium. Isometric contraction measurements and patch clamp technique were used to verify TASK conductance in murine myometrium. Western blot and immunehistochemical study under confocal microscopy were used to investigate molecular identity of TASK channel. In this study, we showed that TEA and 4-AP insensitive non-inactivating outward $K^+$ current (NIOK) may be responsible for the quiescence of murine pregnant longitudinal myometrium. The characteristics of NIOK coincided with two-pore domain acid-sensing $K^+$ channels (TASK-2). NIOK in the presence of $K^+$ channel blockers was inhibited further by TASK inhibitors such as quinidine, bupivacaine, lidocaine, and extracellular acidosis. Furthermore, oxytocin and estrogen inhibited NIOK in pregnant myometrium. When compared to non-pregnant myometrium, pregnant myometrium showed stronger inhibition of NIOK by quinidine and increased immunohistochemical expression of TASK-2. Finally, TASK-2 inhibitors induced strong myometrial contraction even in the presence of L-methionine, a known inhibitor of stretch-activated channels in the longitudinal myometrium of mouse. Activation of TASK-2 channels seems to play an essential role for relaxing uterus during pregnancy and it might be one of the alternatives for preventing preterm delivery.

• Journal of Chest Surgery
• /
• v.2 no.2
• /
• pp.167-167
• /
• 1969

Two groups of esophagus graft were done in canine esophagus in 34 adult mongrel dogs. For the first group segmental replacement graft was done with fresh autologous pericardium tube, and for the second, patch graft was done utilizing fresh autologous pericardium, fresh homologous pericardium,and dacron piece. All eight dogs in the first segmental replacement graft group died 2 to 5 days after operation with severe empyema caused by anastomosis disruption. Among 26 patch graft dogs 2 died during operation and 7 died 13 to 18 days after operation. For the 17 long-term patch grafted survivors esophagography and postoperative weight check were done. Postoperative stool was collected and examined for dacron patch excretion. One, two, three, and four months postoperative long-term survivors were sacrificed to obtain specimens in each group respectively and the following observations were made.I. Survival; Autologous pericardium patch group showed no mortality but in homologous pericardium and dacron patch group only two thirds were long-term survivors. II. Postoperative swallowing; There was no case which demonstrated postoperative dysphagia. About half of the cases showed postoperative weight increase and in only 3 cases weight decrease followed operation. III. Dacron patch was excreted in the stool 8 to 23 days after operation. Animals which excreted dacron patch up to 9 days after operation all died of empyema due to anastomosis disruption.IV. Postoperative esophagogram; All esophagograms in each group showed no leakage of barium, no passage disturbances and no remarkable stenotic signs.V. Morphological findings; [A] Macroscopical findings; In one month group specimens of each group dense adhesion with surrounding structures was noted and luminal surface was smooth with contraction of the patched area. In two month groups anastomosis sutures were still exposed but patched area showed lesser abnormality. In three to four months groups sutures were covered completely and patched area showed only very slight signs of contraction. [B] Microscopic findings; In one month group luminal surface of the replaced tissue [transplanted tissue] showed almost complete epithelial covering that is composed of several layers of squamous cells with no evidence of keratinization. Basement membrane was also well distinct throughout. Slight to minimal inflammatory cells comprising of large mononuclears, lymphocytes and plasma cells were observed in the subepithelial fibrous stroma consisted entirely of loose fibrous tissue containing many newly formed capillaries and fibroblastic proliferation. Scattered suture granulomas were found, few of which became acutely inflamed. In two months group repairing process progressed with lesser degree of inflammatory cell infiltration and young capillary proliferation. Fibrous tissue was more matured showing even focal collagenization.Suture granuloma persisted but with lesser reactive changes. Epithelial covering was that of a mature non-keratinizing stratified squamous epithelium. In three and four months groups the replaced area showed essentially similar histological findings. However, subepithelial stroma still consisted entirely of connective tissue without evidence of smooth muscle regeneration. In this group, inflammatory cell infiltration was minimal or negligible. Among these patch materials autologous pericardium group showed the most satisfactory repairing process.The above mentioned results may signify the feasibility of autogenous pericardium patch graft in clinical esophageal surgery.

• Journal of Chest Surgery
• /
• v.2 no.2
• /
• pp.168-186
• /
• 1969

Two groups of esophagus graft were done in canine esophagus in 34 adult mongrel dogs. For the first group segmental replacement graft was done with fresh autologous pericardium tube, and for the second, patch graft was done utilizing fresh autologous pericardium, fresh homologous pericardium,and dacron piece. All eight dogs in the first segmental replacement graft group died 2 to 5 days after operation with severe empyema caused by anastomosis disruption. Among 26 patch graft dogs 2 died during operation and 7 died 13 to 18 days after operation. For the 17 long-term patch grafted survivors esophagography and postoperative weight check were done. Postoperative stool was collected and examined for dacron patch excretion. One, two, three, and four months postoperative long-term survivors were sacrificed to obtain specimens in each group respectively and the following observations were made. I. Survival; Autologous pericardium patch group showed no mortality but in homologous pericardium and dacron patch group only two thirds were long-term survivors. II. Postoperative swallowing; There was no case which demonstrated postoperative dysphagia. About half of the cases showed postoperative weight increase and in only 3 cases weight decrease followed operation. III. Dacron patch was excreted in the stool 8 to 23 days after operation. Animals which excreted dacron patch up to 9 days after operation all died of empyema due to anastomosis disruption. IV. Postoperative esophagogram; All esophagograms in each group showed no leakage of barium, no passage disturbances and no remarkable stenotic signs. V. Morphological findings; [A] Macroscopical findings; In one month group specimens of each group dense adhesion with surrounding structures was noted and luminal surface was smooth with contraction of the patched area. In two month groups anastomosis sutures were still exposed but patched area showed lesser abnormality. In three to four months groups sutures were covered completely and patched area showed only very slight signs of contraction. [B] Microscopic findings; In one month group luminal surface of the replaced tissue [transplanted tissue] showed almost complete epithelial covering that is composed of several layers of squamous cells with no evidence of keratinization. Basement membrane was also well distinct throughout. Slight to minimal inflammatory cells comprising of large mononuclears, lymphocytes and plasma cells were observed in the subepithelial fibrous stroma consisted entirely of loose fibrous tissue containing many newly formed capillaries and fibroblastic proliferation. Scattered suture granulomas were found, few of which became acutely inflamed. In two months group repairing process progressed with lesser degree of inflammatory cell infiltration and young capillary proliferation. Fibrous tissue was more matured showing even focal collagenization. Suture granuloma persisted but with lesser reactive changes. Epithelial covering was that of a mature non-keratinizing stratified squamous epithelium. In three and four months groups the replaced area showed essentially similar histological findings. However, subepithelial stroma still consisted entirely of connective tissue without evidence of smooth muscle regeneration. In this group, inflammatory cell infiltration was minimal or negligible. Among these patch materials autologous pericardium group showed the most satisfactory repairing process. The above mentioned results may signify the feasibility of autogenous pericardium patch graft in clinical esophageal surgery.

• Korean Journal of Applied Biomechanics
• /
• v.29 no.3
• /
• pp.157-166
• /
• 2019

Objective: This study examined the effects of stimulating fingertip temperature on the patterns of force sharing and stability properties during multi-finger force production tasks. Method: 9 adult subjects (male: 3, female: 6, age: $26.11{\pm}4.01yrs$, height: $169.22{\pm}5.97cm$, weight: $61.44{\pm}11.27kg$) participated in this study. The experiment consisted of three blocks: 1) maximal voluntary contraction (MVC) task, 2) single-finger ramp task to quantify enslaving (i.e., unintended force production by non-task fingers), and 3) 12 trials of multi-finger steady-state force production task at 20% MVC. There were three temperature conditions including body-temperature (i.e., control condition), $40^{\circ}C$, and $43^{\circ}C$, and the stimulation was given to the index finger only for all experimental conditions. Results: There were no significant differences in the MVC forces, enslaving, and the accuracy of performance during the steady-state task between the conditions. However, the share of stimulated index finger force increased with the index fingertip temperature, while the share of middle finger force decreased. Also, the coefficient of variation of both index and middle finger forces over repetitive trials increased with the index fingertip temperature. Under the framework of the uncontrolled manifold (UCM) hypothesis used to quantify indices of multi-finger synergies (i.e., stability property) stabilizing total force during the steady-state task, the two variance components within the UCM analysis increased together with the fingertip temperature, while no changes in the synergy indices between the conditions. Conclusion: The current results showed that fingertip temperature stimulation only to index finger does not affect to muscle force production capability of multi-finger, independence of individual fingers, and force production accuracy by the involvement of all four fingers. The effect of fingertip temperature on the sharing pattern and force variation may be due to diffuse reflex effects of the induced afferent activity on alpha-motoneuronal pools. However, the unchanged stability properties may be the reflection of the active error compensation strategies by non-stimulated finger actions.

• Journal of Adhesion and Interface
• /
• v.25 no.1
• /
• pp.169-274
• /
• 2024

Recent attention has been drawn to materials that undergo reversible expansion and contraction in response to external stimuli, leading to morphological changes. These materials hold potential applications in various fields including soft robotics, sensors, and artificial muscles. In this study, a novel material capable of responding to high temperatures for protection or encapsulation is proposed. To achieve this, liquid crystal elastomer (LCE) with nematic-isotropic transition properties and polyimide (PI) with high mechanical strength and thermal stability were utilized. To utilize a solution process, a dope solution was synthesized and introduced into micro-printing techniques to develop a two-dimensional pattern of LCE/PI bilayer structures with sub-millimeter widths. The honeycomb-patterned LCE/PI bilayer mesh combined the mechanical strength of PI with the high-temperature contraction behavior of LCE, and selective printing of LCE facilitated deformation in desired directions at high temperatures. Consequently, the functionality of selectively and reversibly encapsulating specific high-temperature materials was achieved. This study suggests potential applications in various actuator fields where functionalities can be implemented across different temperature ranges without the need for electrical energy input, contingent upon molecular changes in LCE.

• Journal of Yeungnam Medical Science
• /
• v.14 no.1
• /
• pp.46-52
• /
• 1997

Diaphragm is thought to play the most important role in breathing and has a substantially greater proportion of slow oxidative and fast glycolytic fibers, and low proportion of fast oxidative fibers. The respiratory muscle, diaphragm, has the functional characteristics of slow speed of contraction, high resistance to fatigue and the ability to respond to intermittent ventilatory loads, for example of exercise. In the present study, the characteristics of the metabolism (depletion and repletion) of glycogen and the structural changes of diaphragm during depletion and repletion of glycogen were observed in rats. For comparison, the red gastrocnemius muscle which has a greater proportion of fast oxidative glycolytic (FOG) and slow oxidative (SO) fibers, and low proportion of fast glycolytic (FG) fiber, was also studied. The glycogen concentration of diaphragm in overnight fasted rats was $2.30{\pm}0.14mg/gm$ wet weight. The values of glycogen concentration at 60, 90 and 120minutes of treadmill exercise loaded rats was significantly decreased compared to that of the overnight fasted rats. There was no significant difference among the glycogen concentrations of diaphragm at 60, 90 and 120minutes of exercises. The glycogen concentration of diaphragm was decreased to $1.12{\pm}0.17$ from $2.30{\pm}0.14mg/gm$ wet weight by treadmill exercise. The glycogen depletion rate of diaphragm during exercise was faster than that of red gastrocnemius in both of the first 60minutes and 120minutes duration of exercise. The glycogen repletion of diaphragm after intragastric glucose administration by stomach tube was studied in control and exercise groups. The glycogen concentration was significantly increased after glucose administration in both of control and exercise groups. All of the concentration of exercise group at 60, 120 and 180minutes after glucose administration was significantly higher than those of control group. In conclusion, one of the characteries of diaphragm in glycogen metabolism is fast glycogen depletion during exercise, and slowness of glycogen repletion after glucose ingestion in rats.

• Physical Therapy Korea
• /
• v.20 no.1
• /
• pp.1-9
• /
• 2013

The purpose of this study was to determine the effect of the pelvic compression belt (PCB) on the electromyography (EMG) activities of trunk muscles during sit-to-stand (SitTS), and stand-to-sit (StandTS) tasks. Twenty healthy subjects (7 men and 13 women) were recruited for this study. The subjects performed SitTS, and StandTS tasks, with and without a PCB. Surface EMG was used to record activity of the internal oblique (IO), external oblique (EO), rectus abdominis (RA), erector spinae (ES), and multifidus (MF) of the dominant limb. EMG activity significantly decreased in the RA (without the PCB, $8.34{\pm}6.04$ %maximal voluntary isometric contraction [%MVIC]; with the PCB, $7.64{\pm}5.11$ %MVIC), EO (without the PCB, $14.83{\pm}11.82$ %MVIC; with the PCB, $11.98{\pm}7.60$ %MVIC), MF (without the PCB, $21.74{\pm}7.76$ %MVIC; with the PCB, $18.50{\pm}8.04$ %MVIC), and ES (without the PCB, $18.39{\pm}7.16$ %MVIC; with the PCB, $16.63{\pm}6.31$ %MVIC) during the SitTS task and in the IO (without the PCB, $20.58{\pm}15.60$ %MVIC; with the PCB, $17.27{\pm}12.32$ %MVIlC), RA (without the PCB, $8.04{\pm}5.68$ %MVIC; with the PCB, $7.40{\pm}4.71$ %MVIC), EO (without the PCB, $13.29{\pm}8.80$ %MVIC; with the PCB, $11.24{\pm}6.14$ %MVIC), MF (without the PCB, $18.59{\pm}7.64$ %MVIC; with the PCB, $15.86{\pm}6.48$ %MVIC), and ES (without the PCB, $17.14{\pm}6.44$ %MVIC; with the PCB, $15.46{\pm}5.62$ %MVIC) during the StandTS task when a PCB was used (p<.05). In men the EMG activity of the MF significantly decreased during the SitTS task when a PCB was used (p<.05): in women, the EMG activity of the RA, EO, MF, and ES during the SitTS task and that of the EO, MF, and ES during the SitTS task significantly decreased when a PCB was used (p<.05). In addition, the rates of change in the EMG activity of each muscle differed significantly during the SitTS and StandTS tasks before and after the use of the PCB. However, the EMG activity did not significantly differ between the male and female subjects. These findings suggest that the PCB may contribute to the modification of activation patterns of the trunk muscles during SitTS, and StandTS tasks.

• Korean Journal of Environmental Biology
• /
• v.21 no.3
• /
• pp.313-318
• /
• 2003

Environmental stresses, such as heat shock, alcohol and physiological salt have been shown to induce a group of protein called heat shock protein (HSPs) in various tissues. In this investigation, we studied that arsenic stress would alter contraction of isolated rat aorta and expression of heat shock protein 70 and investigated the relation between expression of HSP 70 and vascular contractility of isolated rat aorta. Rat aorta strips, mounted in organ baths were exposed to 0, 0.5, 1,2 and 4 mM arsonic for 60 min. and 1,3 and 8 hours later tested for contractile response and expression of heat shock protein 70. Contractility of rat aorta were determined by isometric transducer connected to computerized physiograph and expression of HSP 70 was characterized by western blotting, respectively. Potassium chloride (55 mM) significantly augmented vascular contractility of yat aorta by 39％ compared with the control at 8 hours but not one or three hours after treatment of 4 mM arsenic. Arsonic stress (4 mM) also increased the expression of HSP 70 in rat aorta at 8 hours but one or three hours compared with the control and HSP expressed in vascular smooth muscle cells and some expressed in endothelium cells. These results suggest that arsenic stress not only did alter the magnitude of the contractile response to high potassium chloride but also increased the expression of HSP 70 in the rat aorta.

• The Korean Journal of Physiology and Pharmacology
• /
• v.9 no.2
• /
• pp.103-108
• /
• 2005

To study the direct effect of somatostatin (SS) on calcium channel current ($I_{Ba}$) in guinea-pig gastric myocytes, $I_{Ba}$ was recorded by using whole-cell patch clamp technique in single smooth muscle cells. Nicardipine ($1{\mu}M$), a L-type $Ca^{2+}$ channel blocker, inhibited $I_{Ba}$ by $98{\pm}1.9$% (n=5), however $I_{Ba}$ was decreased in a reversible manner by application of SS. The peak $I_{Ba}$ at 0 mV were decreased to $95{\pm}1.5$, $92{\pm}1.9$, $82{\pm}4.0$, $66{\pm}5.8$, $10{\pm}2.9$% at $10^{-10}$, $10^{-9}$, $10^{-8}$, $10^{-7}$, $10^{-5}$ M of SS, respectively (n=3∼6; $mean{\pm}SEM$). The steady-state activation and inactivation curves of $I_{Ba}$ as a function of membrane potentials were well fitted by a Boltzmann equation. Voltage of half-activation ($V_{0.5}$) was $-12{\pm}0.5$ mV in control and $-11{\pm}1.9$ mV in SS treated groups (respectively, n=5). The same values of half-inactivation were $-35{\pm}1.4$ mV and $-35{\pm}1.9$ mV (respectively, n=5). There was no significant difference in activation and inactivation kinetics of $I_{Ba}$ by SS. Inhibitory effect of SS on $I_{Ba}$ was significantly reduced by either dialysis of intracellular solution with $GDP_{\beta}S$, a non-hydrolysable G protein inhibitor, or pretreatment with pertussis toxin (PTX). SS also decreased contraction of guinea-pig gastric antral smooth muscle. In conclusion, SS decreases voltage-dependent L-type calcium channel current ($VDCC_L$) via PTXsensitive signaling pathways in guinea-pig antral circular myocytes.

• The Korean Journal of Physiology and Pharmacology
• /
• v.2 no.4
• /
• pp.461-469
• /
• 1998

Tetrahydroisoquinoline (THI) alkaloids can be considered as cyclized derivatives of simple phenylethy-lamines, and many of them, especially with 6,7-disubstitution, demonstrate relatively high affinity for catecholamines. Two -OH groups at 6 and 7 positions are supposed to be essential to exert ?${\beta}-receptor$ activities. However, it is not clear whether -OH at 6,7 substitution of THIs also shows ?${\alpha}-adrenoceptor$ activities. In the present study, we investigated whether -OH or $-OCH_3$ substitutions of 6,7 position of THIs differently affect the ?1-adrenoceptor affinity. We synthesized two 1-naphthylmethyl THI alkaloids, $1-{\beta}-naphthylmethyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline$ HBr (YS 51) and $1-{\beta}-naphthylmethyl-6, 7-dimethoxy-1,2,3,4-tetrahydroisoquinoline$ HCl (YS 55), and their pharmacological actions on ?${\alpha}_1-adrenoceptor$ were compared. YS 51 and YS 55, concentration-dependently relaxed endothelium-denuded rat thoracic aorta precontracted with phenylephrine (PE, 0.1 ${\mu}M$) in which $pEC_{50}$ were $5.89{\pm}0.21$ and $5.93{\pm}0.19$, respectively. Propranolol (30 nM) did not affect the relaxation-response curves to YS 51 and YS 55. Concentration-response curves to PE were shifted to right by the pretreatment with YS 51 or YS 55. The $pA_2$ values of YS 51 and YS 55 showed $6.05{\pm}0.24$ and $5.88{\pm}0.16$, respectively. Both probes relaxed KCl (65.4 mM)-contracted aorta and inhibited $CaCl_2-induced$ contraction of PE-stimulated endothelium- denuded rat thoracic aorta in $Ca^{2+}-free$ solutions. In isolated guinea pig papillary muscle, 1 and 10 ${\mu}M$ YS 51 increased contractile force about 4- and 8- fold over the control, respectively, along with the concentration-dependent increment of cytosolic $Ca^{2+}$ ions. While, 10 ${\mu}M$ YS 55 reduced the contractile force about 50 % over the control and lowered the cytosolic $Ca^{2+}$ level, in rat brain homogenates, YS 51 and YS 55 displaced $[^3H]prazosin$ binding competitively with Ki 0.15 and 0.12 ${\mu}M$, respectively. However, both probes were ineffective on $[^3H]nitrendipine$ binding. Therefore, it is concluded that two synthetic naphthylmethyl-THI alkaloids have considerable affinity to ?1-adrenenoceptors in rat aorta and brain.