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Among all industrial accident-induced diseases, musculoskeletal disorders (MSDs) are most prominently observed among nurses. The physical load of everyday tasks involved in nursing work was assessed in this study using a developed risk index, whereby the physical burden was evaluated using the exposure duration and work intensity levels. This survey targeted nine small-, medium-, and large-sized hospitals in South Korea and categorized representative nursing tasks into six groups. The subtasks within these six categories (evaluated as high risk) included changing a patient's posture and assisting with walkers or wheelchairs, transporting/handling drug carts, bathing patients, replacing bedding, traction therapy, cardiopulmonary resuscitation and artificial manual breathing unit, and computer work. The risk index ratio was significantly different by task type for each task. We demonstrated that the risk index developed in this study can be used to evaluate MSDs in hospitals.

One form of abnormal scapular alignment is scapular downward rotation (SDR). Changes in muscle function in SDR have not been clearly identified, and SDR exercises also require investigation. Although a diagonal pattern of exercise is commonly used as part of the exercise protocol, a direct comparison of shoulder and scapular diagonal exercises has not yet been conducted. The objectives of this study were to determine the altered activation of the scapular musculature in the SDR group and to investigate which diagonal pattern of exercise effectively activates the scapular musculature.Thirty-two participants (18 in the control group and 14 in the SDR group) volunteered to participate in this study. Electromyographic signals were collected from four muscles, the upper trapezius (UT), lower trapezius (LT), serratus anterior (SA), and anterior deltoid (AD), during standing performance of diagonal shoulder and scapular exercises.The control group showed significantly lower UT activity, UT/LT ratio, and UT/SA values than the SDR group (p .05). Activation of the AD was significantly higher in the SDR than in the control group (p .05). SA and AD activation were significantly higher in shoulder diagonal pattern exercises than in scapular diagonal pattern exercises (p .05). The scapular posterior elevation pattern exercise showed significantly higher UT and LT activities than anterior elevation and shoulder diagonal pattern exercises (p .05).Our findings suggest that reduced activation of the UT could lead to greater activation in the AD in SDR. Scapular posterior elevation exercise is advantageous as selectively activates the trapezius musculature, and shoulder diagonal pattern exercise is advantageous in activating the SA and AD.

BACKGROUND: Problems related to ankle instability, decreased proprioceptive sensation, altered static and dynamic balance abilities are suggested as major representative factors that contribute to the recurrence of ankle sprains. OBJECTIVE: To assess the effect of a three-week intervention (intervention emphasizing diagonal eccentric contraction (IEDEC) and intervention of general exercise (IGE)) on static and dynamic balance abilities, ankle strength and joint position sense at pre- and post-intervention, and at two- and three-week post-intervention. METHODS: Twenty-five participants with ankle instability, including a history of ankle sprain and recurrent episodes of giving way, were enrolled in the study. They were randomly classified into the IEDEC group (n= 12) and the IGE group (n= 13). Dynamic balance was examined using the Y Balance Test, four-way ankle strength was measured, and the static balance was evaluated using the total displacement of the center of pressure (COP). To identify the joint position error, eversion and inversion of the ankle angle were measured. RESULTS: The results revealed significant increases in ankle dynamic stability and strength at two and three weeks post-intervention (p< 0.05). Similarly, the total displacement of the COP differed significantly over time, with a higher COP during the initial measurement than at two and three weeks intervention (p< 0.05) General balance training with IEDEC can improve position sense during ankle inversion (p< 0.05). CONCLUSION: General balance training with IEDEC improved the position sense of the inversion. Combined therapeutic intervention, such as with the manual technique, could be a beneficial approach to maximize the treatment effects.

Background: In recent years, a three-dimensional ankle exercise has been proposed as a practice for strengthening the intrinsic foot muscles, however this topic still requires further research. This study aimed to compare the activities of the intrinsic muscles in healthy participants during 3D foot&ndash, ankle exercises, namely, short foot (SF), and toe spread out (TSO). Methods: Prior to the experiment, 16 healthy adults were trained on how to perform SF, TSO, and 3D foot&ndash, ankle exercises for an hour. Once all participants passed the foot&ndash, ankle exercise performance test, we randomly measured the activity of the intrinsic foot muscles using electromyography while the patients were performing foot&ndash, ankle exercises. Results: The abductor hallucis (AbH), extensor hallucis longus (EHL), and flexor hallucis brevis (FHB) activities showed significant differences among the exercises for intrinsic foot muscle strengthening (p &lt, 0.01). Additionally, the AbH/AdH (adductor hallucis) ratio showed significant differences among the exercises for strengthening the intrinsic foot muscles (p &lt, 0.01). Conclusions: Our results showed that the 3D extension exercise is as effective as the therapeutic exercise in terms of the AbH and FHB activities, and the AbH/AdH ratio. On the contrary, the 3D flexion exercise showed superiority in terms of the EHL activity.

Background General ankle-foot orthosis (AFO) cannot be flexibly adjusted to volumetric change in the lower leg because the molding is custom-fit. Thus, we developed a flexible assistive device called elastic neutral AFO (EN-AFO) to help stroke patients hold a neutral ankle position. The purpose of this study was to investigate the effects of EN-AFO and improve gait patterns in stroke patients with rearfoot varus deformity. Methods Fifteen stroke patients with a varus deformity of the foot performed a walking test with and without the use of EN-AFO. Kinematic data were measured with a 3D motion analysis system with inertial measurement unit (IMU) sensors. Results In the stance phase, maximal pelvic tilt and maximal ankle dorsiflexion in the affected side changed, and maximal and minimal pelvic tilts and maximal hip abduction in the less-affected limb effectively changed, as well. During the swing phase, minimal pelvic tilt and minimal ankle abduction in the affective limb greatly changed; particularly, the reduction of maximal ankle inversion was significantly cleared. Conclusions The EN-AFO was effective in controlling the tendency of foot inversion in patients with varus deformities. This is suitable for gait training, as it can adjust the orthosis stiffness according to the foot condition.

The present study aimed to investigate lumbar multifidus (LM) thickness and perceived exertion during graded superman exercises (GSE) or GSE with an abdominal drawing-in maneuver (GSE-AD) in young adults. Twelve young adult males and females, who were informed of the purpose and procedures of this study and then gave their voluntary consent to participate, were included in this study. All subjects randomly performed three GSE and GSE-AD over 3 days. Ultrasonography was used to measure the LM thickness to the left and right of the L5 region. Additionally, the issue of whole-body fatigue felt by the subject while performing the GSE or GSE-AD was measured using the Borg scale. The intrarater reliability of the LM measurement was found to be intraclass correlation coefficient (ICC[3,1])=0.97 (0.87–0.99) at resting and ICC(3,1)=0.94 (0.78–0.99) at contraction. Both the left and right LM showed significantly higher contraction during the grade 3 GSE (P< 0.05). The whole-body fatigue was significantly greater following GSE 2 and 3 than following GSE-AD 2 and 3 (P0.05). It is recommended that the abdominal drawing-in maneuver be applied with grade 3 GSE to enhance stability and reduce spinal fatigue.

This study investigated potential for foot dysfunction and plantar fasciitis according to the shape of the foot arch in young adults. Fifty-two participants were required for the present study design to achieve 80% power, 0.8 effect size (η2), and an alpha level of 0.05. This study recruited 52 young adults (30 men and 22 women). All participants voluntarily agreed to participate in the study after hearing explanations about the purpose and process of the study. They were divided into two groups of 26 according to the shape of foot with and without flat foot using the navicular drop test. The participants were measured the foot function index (FFI), range of motion (ROM) of ankle, and four-way ankle strength. Additionally, the thickness of the plantar fascia was measured using ultrasonography. Intraclass correlation coefficient (ICC) was used to verify the inter- and intrarater reliability of ultrasonography. The inter- and intrarater reliability was excellent (ICC2,1=0.88, ICC3,1=0.93). There were significant differences in dorsi-flexion of ankle ROM, FFI, dorsi-flexion and eversion of ankle strength, and the thickness of the plantar fascia between the two groups (P

Many experts have used an indirect method for enhancing strength and performance of muscles in clinical practice. The indirect method, which called an irradiation is a basic procedure of proprioceptive neuromuscular facilitation, there is little research related the effects of irradiation. This study investigated abdominal muscle activity during abdominal drawing-in maneuver (ADIM) combined with irradiation variations. The study recruited 42 healthy, young adults who were divided randomly into three groups according to which intervention they received. The first group performed the ADIM combined with coactivation of the pelvic floor muscle. The second group performed the ADIM combined with the irradiation resulting from dorsiflexion of the ankle. The third group performed the ADIM combined with the irradiation resulting from bilateral arm extension. Electromyography data were collected from the rectus abdominis, external oblique abdominis, and transversus abdominis/internal oblique abdominis (TrA/IO) muscles during ADIM combined with irradiation variations. There were significant differences in the abdominal muscle activity and the preferential contraction ratio of the TrA/IO among the three groups (P

BACKGROUND Various forms of trunk exercise have been used for increasing abdominal strength. The plank exercise and bilateral leg raise exercise are one of these trunk exercises. However, there are few studies that compared the effects of these exercise variations. OBJECTIVE The present study aimed to investigate how effectively the trunk muscles during plank and bilateral leg raise exercises are activated. METHOD Surface electromyography responses of the rectus abdominis, internal oblique, and erector spinae muscles were investigated during the plank and bilateral leg raise exercise with different hip position. A total of 18 healthy, physically active female volunteers completed the normal plank exercise, plank exercise with placing the lower leg in a horizontal condition, bilateral leg raise exercise, and bilateral leg raise with lower leg as horizontal condition. RESULTS The horizontal condition caused significant increases in activity of the internal oblique muscles compared with the general condition (p< 0.05). The bilateral leg raise exercise showed significantly greater activation in the rectus abdominis compared to the plank exercise (p< 0.05). CONCLUSION The present study showed that the horizontal condition had the advantage of activating the internal oblique muscles, and the leg raise exercise is effective in strengthening global muscle such as the rectus abdominis.

BACKGROUND A high prevalence and incidence of neck and shoulder pain are common problems that require more attention from health service providers and researchers. Recent findings have indicated that the neck stretching is the one of the most effective physical therapy interventions. Although the recovery of the pain through the stretching exercise has been described in a previous study, functional advantages and changes of the neuromuscular control has not been suggested. Additionally, there was a lack of studies that considered methods of stretching. OBJECTIVE The purpose of the present study was to examine the long-term effects of stretching methods for cervical neuromuscular dysfunction, disability and pain in a sample of sedentary workers with neck pain. METHODS Twenty-four sedentary workers with neck pain participated in this study and were assigned to the following two groups: static stretching (SS), and diagonal active stretching (DS). Active cervical range of motion (ROM), pressure pain threshold (PPT), self reported questionnaire (Neck Disability Index, NDI), and the flexion - relaxation ratio (FRR) from the cervical erector spinae muscles were measured at pre-treatment, post-treatment (after 4 weeks) and follow-up (after 6 and 8 weeks). RESULTS In both groups, the values obtained for the cervical ROM as flexion, extension, lateral flexion, were significantly increased in comparison to pre-treatment (p< 0.05). Significant increases of the left and right neck rotation, left and right FRR were only observed in the DS group (p

Background We hypothesised that the balance of spastic chronic stroke patients is related to myofascial problems. We performed myofascial release (MFR) with a tennis ball on the affected limb, as suggested by Myers. Purpose This study investigated the benefits of 8 weeks of MFR using a tennis ball on the balance of spastic patients. Methods Eight stroke patients were enrolled voluntarily after providing informed consent. All subjects received 8-week interventions with MFR using a tennis ball three times per week. The patients were evaluated using the Berg Balance Scale (BBS) and Timed ‘Up & Go' (TUG) test before and after 4 and 8 weeks of the intervention. Results There were significant differences in the BBS scores ( p = 0.001). The TUG time decreased significantly at 4 and 8 weeks ( p = 0.034). Conclusion Myofascial release appears to improve the balance of spastic chronic stroke patients; however, further studies should evaluate the effective of MFR on walking in stroke patients and determine the mechanism of the effect of MFR.

The purpose of this study was to identify the changes in the cervical range of motion (CROM), the cervical flexion-relaxation ratio (CFRR), and neck pain after dynamic neck training (DNT) combined with hold-relax technique (HRT) for young college students with video display terminal (VDT) syndrome. For this study, 15 young college students with VDT syndrome were recruited. DNT combined with HRT was applied to all participants in a sitting position for 15 min. Postintervention, the CROM and the CFRR were significantly higher than preintervention, and neck pain had significantly decreased. DNT combined with HRT showed immediate effects on the CROM, the CFRR, and neck pain in young college students with VDT syndrome.

The purpose of this study was to investigate changes of gait pattern, muscle activity, and perceived comfort in response to variations of height-elevating insoles (HEIs) in young adults. The subjects of this study were 30 young adults who voluntarily consented to participate in this experiment after listening to its purpose and method. They were di-vided into 3 groups who wore HEIs height (0, 3, and 7 cm). Each group consisted of 10 young adults and wore the HEIs for 4 hr a day. Electro-myographic signals were collected from the tibialis anterior, the gas-trocnemius, the hamstring, and the right and the left erector spinae (ES) before and after walking with the HEI. Gait pattern was measured be-fore and after walking with the HEI. Perceived comfort was measured after a subject wore the insoles for 4 hr. The activities of ES showed significant differences among the three groups. The activity of the left ES was significantly different between groups 1 (0 cm) and 2 (3 cm) and groups 1 and 3 (7 cm). The activity of the right ES was significantly dif-ferent between groups 1 and 3. The left stride length and the left step length showed significant differences between groups 1 and 3. Per-ceived comfort was significantly different among the three groups. As the HEIs increased, the activities of ES were gradually increased and the left step length and stride were decreased. Using of higher HEIs over 4 hr may be occurred excessive activities of the ES, abnormal gait patterns, and perceived discomfort.

[Purpose] This study investigated the effects of visual stimulus using central and peripheral vision fields on postural control. [Subjects and Methods] The subjects consisted of 40 young adult volunteers (15 males, 25 females) who had been informed of the study purpose and procedure. The subjects were randomly divided into four groups of differing visual stimulus. Each group was given visual intervention in a standing position for 3 minutes. Postural control was evaluated before and after visual intervention. [Results] The results of the functional reach test and body sway test showed significant differences among the four groups. [Conclusion] The two-way peripheral vision-field group showed significantly more body sway after visual intervention than the other three groups. This finding may suggest two-way peripheral vision field is a more effective visual stimulus for training postural control and balance.

This study investigated the reliability of ultrasound in combination with surface electromyogram (EMG) for evaluating the activity of the abdominal muscles in individuals with and without low back pain during the abdominal drawing-in maneuver (ADIM). The study recruited ten individuals with or without low back pain, respectively. While the participants were performing the ADIM, the activities of the transversus abdominis (TrA) and the internal oblique (IO) were measured using ultra-sound, while the activities of the external oblique (EO) and the rectus abdominis (RA) were measured using surface EMG. Intra-class correlation coefficients (ICC) were used to verify the inter-rater reliability of ultrasound in combination with surface EMG at rest and during the ADIM, and Bland-Altman plots were used to verify intra-rater reliability. The inter-rater reliability for the two groups at rest and during the ADIM was excellent (ICC2,1 = 0.77–0.95). In the Bland-Altman plots, the mean differences and 95% limits of agreement in the abdominal muscles of the two groups at rest were −0.03∼0.03 mm (−0.66 to 0.60 mm) and −0.12∼ −0.05 (−0.58 to 0.48% MVIC), respectively. The mean differences and 95% limits of agreement in the abdominal muscles of the two groups during the ADIM were −0.04∼0.02 mm (−0.73 to 0.65 mm) and −0.19∼0.05% MVIC (−1.24 to 1.34% MVIC), respectively. The ultrasound in combination with surface EMG showed excellent inter-rater and intra-rater reliability at rest and during the ADIM.

The objective of this study was to determine appropriate knee angles for the abdominal drawing-in maneuver (ADIM) through evaluation of changes in contraction ratios of the abdominal muscles and activity of quadriceps muscle in relation to changes in knee angles occurring while the ADIM is performed in the wall support standing (WSS). 20 subjects performed the ADIM at different knee angles (0°, 20°, 40°, 60°) in random order, standing at a point 6 inches away from the wall with the spine maintained in the neutral position. The WSS with knee flexion at 20° showed significantly higher preferential contraction ratio (PCR) of transversus abdominis (TrA) compared to other positions (0°, 40°, 60°). Therefore, performing the ADIM in the WSS with knee flexion at 20° appears to be the most appropriate position for TrA PCR.

[Purpose] The purpose of this study was to research the effect of performing the suboccipital muscle inhibition (SMI) and self-myofascial release (SMFR) techniques in the suboccipital area on the flexibility of the hamstring. [Subjects] Fifty persons with short hamstrings participated in this research. According to the results of the finger-floor distance (FFD) test, the subjects were allocated to SMI and SMFR groups of 25 subjects each. [Methods] The SMI and SMFR techniques were applied to the groups. For the analysis, we used the FFD test and the straight leg raise (SLR) test for the flexibility of hamstring. The evaluator was blindfolded. [Results] In the SMI group, FFD, SLR, and PA were significantly changed after the intervention, and in the SMFR group, there was a significant change in SLR after the intervention. In a comparison between the groups, FED was found to be significantly increased in the SMI group. [Conclusion] Application of the SMI and SMFR to persons with short hamstrings resulted in immediate increases in flexibility of the hamstring. However, we could see that the SMI technique was more effective.

[Purpose] The purpose of this study was to examine the effects of the flexion angle of the knee joint and the abduction angle of the hip joint on the activation of the cervical region and abdominal muscles. [Subjects] A total of 42 subjects were enrolled 9 males and 33 females. [Methods] The bridging exercise in this study was one form of exercise with a knee joint flexion angle of 90°. Based on this, a bridging exercise was conducted at the postures of abduction of the lower extremities at 0, 5, 10, and 15°. [Result] The changes in the knee joint angle and the hip abduction angle exhibited statistically significant effects on the cervical erector spinae, adductor magnus, and gluteus medius muscles. The abduction angles did not result in statistically significant effects on the upper trapezium, erector spinae, external oblique, and rectus abdominis muscles. However, in relation to the knee joint angles, during the bridging exercise, statistically significant results were exhibited. [Conclusion] When patients with both cervical and back pain do a bridging exercise, widening the knee joint angle would reduce cervical and shoulder muscle activity through minimal levels of abduction, permitting trunk muscle strengthening with reduced cervical muscle activity. This method would be helpful for strengthening trunk muscles in a selective manner.

[Purpose] The aim of this study was to determine the appropriate pressure variation for performing a successful abdominal drawing-in maneuver (ADIM). The abdominal muscle thickness variations and contraction ratios were examined in relation to pressure variations using a Pressure Biofeedback Unit (PBU) during an ADIM in the supine position. [Methods] The PBU was placed identically between the lumbar lordosis of 20 healthy subjects (12 males and 8 females) and the pressure of the PBU was maintained at 40 mmHg. Then, while the subjects performed ADIM at four random pressure variations (0, 2, 4, or 6 mmHg), the thicknesses of the transversus abdominis (TrA), the internal oblique abdominal muscle (IO), and the external oblique abdominal muscle (EO) were measured using ultrasonography. [Results] Pressure increases of 0-2 mmHg resulted in significant decreases in IO and EO thicknesses compared to pressure increases of 6 mmHg. Increases of 0-2 mmHg also resulted in significant decreases in IO+EO and EO contraction ratios compared to pressure increases of 6 mmHg, while the preferential activation ratio of the TrA was significantly increased. [Conclusion] Compared to the other pressure increases, an increase of 0-2 mmHg effectively regulated the thicknesses and contraction ratios of superficial muscles such as IO and EO, rather than the thickness and contraction ratio of the TrA, showing high and indirect preferential activation ratios for TrA. Therefore, for successful ADIM, rather than using large PBU pressure increases, exercises that promote slight increases of around 0-2 mmHg from a baseline of 40 mmHg are desirable.

This study was conducted to examine the influence of the peripheral vision (PV) induced by moving people on postural control in healthy adults. The subjects consisted of 12 healthy adult volunteers (5 males, 7 females) who had been informed of the study purpose and procedure. The visual interventions were composed of three types. PV1 and PV2 were stimulated using a one-way vertical striped pattern and a two-way vertical striped pattern, respectively. To embody the features of moving people reflected in the mirrors, researchers recorded movements of people or objects provided by mirrors on video image. In this study, this was named PV3. The subjects were exposed to each of the visual stimuli for 3 min in a random order, and their postural control was then evaluated. All the subjects were allowed to practice once prior to performing the one leg stand test, functional reaching test and body sway test. All the evaluations were made before and after the visual intervention, and the subjects rested for 30 min between each intervention. PV3 ranked second in before and after differences of trace length and velocity and had no significant difference from PV2, demonstrating that the PV3, as well as PV2, affected the amount and velocity of body sway. In addition, the standard deviation velocity, trace length and velocity values of PV3 were higher than the PV1 values. Therefore, the treatment of those who have difficulty with postural control and balance maintenance should take place in a controlled therapeutic environment.

[Purpose] This study examined the effects of a conventional quadriceps setting exercise (CQS) and a modified quadriceps setting exercise (MQS) on the strength of the quadriceps femoris, hamstring and gluteus maximus muscles, and the walking ability of elderly persons with osteoarthritis (OA) during their early rehabilitation after total knee arthroplasty (TKA). [Subjects] The subject of this study were 44 elderly women aged 65 or over who were scheduled to undergo TKA on one knee and who voluntarily consented to participate in this experiment after listening to its purpose and method. We divided the subjects into an experimental group (n=22) who performed MQS and a control group (n=22) who performed CQS. [Methods] We measured subjectsAf muscle strength and conducted the 6-minute walk test (6MWT) before surgery, 2 weeks after surgery, and 4 weeks after surgery. [Results] Changes in the strength of the hamstring and gluteus maximus muscles were significantly different between the two groups. [Conclusion] MQS may enhance the strength of the hamstring as well as gluteus maximus muscles and is considered an appropriate exercise for the elderly in their early rehabilitation after TKA.

[Purpose] This study was conducted to investigate the effects of rehabilitative ultrasound imaging (RUSI) feedback during the abdominal hollowing exercise (AHE) in three different positions by monitoring the changes in the thicknesses of the abdominal muscles. [Subjects] The subjects of this study were 42 healthy male adults who listened to an explanation of the study method and purpose and agreed to participate in the experiments. They were divided into an experimental group of 21 subjects who received RUSI feedback and a control group of 21 subjects who did not receive RUSI feedback. [Methods] The thickness of the abdominal muscles was measured during rest and AHE in three positions. The thickness changes between rest and AHE were compared between the two groups. [Results] The difference in internal abdominal oblique (IO) thickness changes between the groups were significant. The differences in external abdominal oblique (EO) thickness changes were only significant among the positions. A post hoc analysis of the differences in EO thickness changes among the positions found significant differences between the crook lying and four-point kneeling positions. The transversus abdominis (TrA) thickness changes showed significant interaction between group and position. [Conclusion] RUSI feedback assists the independent activities of TrA by decreasing the thickness changes of global muscles such as IO and EO. Furthermore, crook lying is a more effective position in AH training with RUSI feedback than the other two positions as it increases TrA thickness changes while minimizing those of EO.

[Purpose] This study examined the activities of the rectus abdominis (RA), external abdominal oblique (EO), transversus abdominis and internal abdominal oblique (TrA/IO) while abdominal hollowing (AH) was performed in four different positions (crook lying, prone lying, four-point kneeling, wall support standing). [Subjects] Experiments were conducted on 36 healthy male adults (mean age=24.44 years) who voluntarily agreed to participate in the experiments. [Methods] Each subject was instructed regarding maximal voluntary contractions (MVC) and AH. While the MVC and AH of individual muscles were being performed, the activity of the muscles was measured using surface electromyography (EMG). The activity of the muscles while performing AH was normalized to percentages of MVC. [Results] TrA/IO showed significant differences among the positions and showed the highest muscle activity for prone lying. [Conclusion] The contraction of the TrA/IO was shown to be the highest muscle activity in prone lying. Therefore, we consider that various kinds of technique can eliminate EO activity during performing AH in prone lying.

[Purpose] This study examined the effects of diagonal shoulder training on an individual with secondary impingement due to scapular dyskinesis. [Subject] A 54 year-old female with secondary impingement participated in this study. [Methods] The patient performed diagonal shoulder training in 4-point kneeling, 3 times per day for 20 minutes over a period of 6 weeks. Evaluations of shoulder pain, range of motion, upper trapezius/lower serratus anterior ratio, and impingement were performed before training and at 2, 4, and 6 weeks. [Results] The patient’s parameters improved gradually. All parameters returned to normal ranges at 4 weeks. [Conclusion] Diagonal shoulder training is effective for improving dysfunction in individuals with secondary impingement. In addition, this training should be applied for more than 4 weeks.

Background: This study was conducted to determine the effects of dexamethasone and MK-801 on the formation of brain edema resulting from a focal ischemic injury by middle cerebral artery occlusion in rats. Methods : Fifteen Sprague-Dawley rats (220 280 g) were freely allowed to drink and eat until just before surgery. Anesthesia was induced with 4% isoflurane in oxygen and then maintained with 2% isoflurane in oxygen. Ischemic injury was induced by an intraluminal suture with a blunted tip inserted into the internal carotid artery and occlusion of the middle cerebral artery. All rats were divided randomly into three groups. In group I (n = 5), normal saline 1 ml was injected intravenously 10 minutes before MCA occlusion. In group II (n = 5), dexamethasone 3 mg/kg was administered 10 minutes before injury. In group III (n = 5), a N-methyl-D-aspartate receptor antagonist, MK-801 1 mg/kg was injected 30 minutes before injury. Rectal temperatures were monitored during the experiment. After 60 minutes of MCA occlusion, the intraluminal sutures were removed and all the rats were returned to their cages. Their brain were quickly removed and the cerebral hemispheres were sepaerated into ischemic cores and penumbra zones after 1 hour of reperfusion. The separated cerebral hemispheres were dried 7 days at 60oC dry oven. The cerebral water content was assessed by the dry-weight method. Results: In the dexamethasone group, there were no significant changes in cerebral edema formation in both ischemic core and the penumbra. In the MK-801 group, there were significant reductions in the brain edema formation in the penumbra (P＜ 0.05), but not in the core. Conclusions : Dexamethasone has no effect on ischemic brain edema; however, MK-801 is effective in the ischemic penumbra zone by reducing of edema formation. (Korean J Anesthesiol 1999; 37: 327∼333)