Antiallodynic effects of vitamin C and vitamin E in chronic post-ischemia pain rat model / 대한마취과학회지

BACKGROUND: Recent research has shown that reactive oxygen species (ROS) play a significant role in the development and persistence of neuropathic pain through central sensitization via N-methyl-D-aspartate (NMDA) receptor activation. In the present study, we examined whether the intraperitoneal administration of vitamins C and E alone or together could alleviate mechanical allodynia in a chronic post-ischemia pain (CPIP) rat model. METHODS: Vitamins C and E were administered intraperitoneally to 48 male Sprague Dawley rats once per day for 3 days before hindpaw ischemia-reperfusion (I/R) injury was induced. On the third day, the CPIP rat model was produced by inducing ischemia in the left hindpaw by applying an O-ring for 3 h, followed by reperfusion. Three days after reperfusion, hindpaw mechanical allodynia was assessed by measuring the withdrawal response to von Frey filament stimulation. The rats were sacrificed immediately after behavioral testing to determine the phosphorylated NMDA receptor subunit 1 (pNR1) and extracellular-signal-regulated kinases (pERK) levels in the spinal cord. RESULTS: When the antioxidant vitamins C and E were administered intraperitoneally to CPIP rats, I/R injury-induced mechanical allodynia was attenuated, and pNR1 and pERK levels were decreased in the rat spinal cord. Additionally, the co-administration of both vitamins had an increased antiallodynic effect. CONCLUSIONS: The reduced phosphorylated NR1 and ERK levels indicate that vitamins C and E inhibit the modulation of spinal cord neuropathic pain processing. Co-administration of vitamins C and E had a greater antiallodynic effect.

Cultured human chromaffin cells grafted in spinal subarachnoid space relieves allodynia in a pain rat model / 대한마취과학회지

BACKGROUND: Implantation of xenogenic chromaffin cells into the spinal subarachnoid space can produce analgesia in neuropathic pain models. However, transplantation of xenogeneic chromaffin cell has a potential risk of viral or bacterial infections from animals to humans including encephalopathy due to prion transmission. The aim of this study was to investigate the possibility of developing a homogeneic source of therapeutic chromaffin cells. METHODS: Anti-allodynic effects of human chromaffin cells (HCCs) were evaluated in a neuropathic pain model in rats induced by chronic constriction injury of the sciatic nerve. HCCs encapsulated with alginate-poly-L-lysine-alginate were intrathecally implanted into rats (n = 10), while empty capsules were intrathecally implanted as a control (n = 8). Levels of norepinephrine from encapsulated HCCs before and after nicotinic stimulation were measured. We then perfomed a behavior test (cold allodynia) with acetone. In addition, to assess the potential contribution to pain reduction of opioid peptides released from the HCCs, all animals were injected with naloxone. RESULTS: The concentration of norepinephrine after nicotine stimulation was significantly increased compared to basal levels. Intrathecal implantation of encapsulated HCCs, significantly reduced cold allodynia as compared to rats receiving empty capsules (P < 0.05). Fifteen minutes after the injection of naloxone, cold allodynia significantly decreased in rats with HCCs (P < 0.05), while the degree of cold allodynia in control animals was unaltered. CONCLUSIONS: From these results, it appears that HCCs have a possibility as an analgesic source for transplants delivering pain-reducing neuroactive substances.

Effect of pretreatment with acetaminophen on withdrawal movements associated with injection of rocuronium: a prospective, randomized, double-blind, placebo controlled study / 대한마취과학회지

BACKGROUND: Withdrawal movement during rocuronium injection is a common, unresolved adverse effect. We aimed to investigate the effect of IV acetaminophen pretreatment on withdrawal movement during rocuronium injection. METHODS: This study enrolled 120 American Society of Anesthesiologists (ASA) I-II patients undergoing general anesthesia. They were randomly assigned to three treatment groups. After occluding venous drainage using a tourniquet on the upper arm, the saline group received 5 ml of 0.9% sodium chloride solution, the lidocaine group received 40 mg of lidocaine, and the acetaminophen group received 50 mg of acetaminophen. During injection of pretreatment drug, pain was assessed on a four-point scale. The tourniquet was released after 120 seconds and anesthesia was performed using thiopental sodium 5 mg/kg followed by rocuronium 0.6 mg/kg. The withdrawal movement was graded on a four-point scale in a double-blind manner. RESULTS: The incidence of pain on pretreatment injection in saline, lidocaine, and acetaminophen groups was 7.7%, 5.1%, and 2.5%, respectively. The incidence of withdrawal movements was 77.5% in saline group, 32.5% in lidocaine group, and 37.5% in acetaminophen group (P < 0.05). CONCLUSIONS: Acetaminophen and lidocaine reduced the incidence of withdrawal movement after rocuronium injection compared with saline.

Contralateral allodynia and central change in the chronic post-ischemic pain model rats / 대한마취과학회지

BACKGROUND: Mirror-image allodynia is a mysterious phenomenon that occurs in association with many clinical pain syndromes including complex regional pain syndromes (CRPS). Underlying mechanisms for the development of such pain are still a matter of investigation. Several studies suggest that activation of the N-methyl-D-aspartate (NMDA) receptor is essential for central sensitization as a base for persistent pain. The aim is to assess whether alteration of NMDA receptor expression correlates with the contralateral allodynia in the chronic post-ischemia pain (CPIP) model rats representing CRPS-Type I. METHODS: Application of a tight-fitting tourniquet for a period of 3 hours before reperfusion produced CPIP in male Sprague-Dawley rats. The mechanical paw withdrawal thresholds to von Frey stimuli (using a dynamic plantar aesthesiometer) were measured as pain indicators in ipsilateral and contralateral hindpaws. Phosphorylation of the NMDA receptor 1 subunit (pNR1), assessed with Western blot, was measured in the contralateral L4-6 spinal cord. RESULTS: Ipsilateral and contralateral mechanical allodynia is present at 4 hours after reperfusion, peaked at 3 days, and continued for 7 days after reperfusion. The relative density of pNR1 of CPIP rats significantly decreased in the contralateral L4-6 spinal cord compared to baseline value (P < 0.05). There was significant correlation between paw withdrawal threshold and the relative density of pNR1 (ipsilateral; R2 = 0.75, P < 0.01, contralateral; R2 = 0.60, P < 0.01). CONCLUSIONS: These data suggest that pNR1 is correlated to the contralateral mechanical allodynia in CPIP rats.

Comparision of Total Intravenous Anesthesia and Sevoflurane-N2O-Alfentanil Anesthesia for Laryngeal Microscopic Surgery / 대한마취과학회지

BACKGROUND: The aim of this study was to compare the clinical properties of sevoflurane-N2O-alfentanil with propofol- remifentanil anesthesia for patients undergoing laryngeal microscopic surgery. METHODS: Sixty patients scheduled for elective ambulatory surgery received either total intravenous anesthesia (TIVA group) with remifentanil and propofol or balanced anesthesia with sevoflurane-N2O-alfentanil (sevoflurane-N2O-alfentanil group). The TIVA group patients were induced with an effective-site concentration of 4microgram/ml propofol and a bolus dose of 0.5microgram/ml remifentanil. The anesthesia was maintained with a continuous infusions with an effective-site concentration of 2-5microgram/kg propofol and 0.05-0.5microgram/kg/min remifentanil, according to the hemodynamic response. The sevoflurane-N2O-alfentanil group patients were induced with 5 mg/kg thiopental and 20microgram/kg IV alfentanil. Maintenance was obtained with 1.5-3.0 vol% sevoflurane and a bolus dose of 10microgram/kg IV alfentanil if needed. The anesthetic depth was controlled under bispectral index (BIS) monitoring: propofol and sevoflurane concentrations were adjusted to achieve target BIS values, and were between levels of 40-60 during surgery. RESULTS: Both anesthetic methods provided acceptable hemodynamic responses during surgery. The late recovery times (postanesthetic discharge scoring system), patient satisfaction and postoperative side effects were similar between patients in the two groups. Early recovery times (eye opening and the aldrete score) were shorter in the TIVA group patients, but this difference was not associated with a shorter hospital length of stay. CONCLUSIONS: Total intravenous anesthesia with remifentanil-propofol and balanced anesthesia with sevoflurane-N2O-alfentanil both provided satisfactory anesthesia for laryngeal microscopic surgeryd

Change of Post-anesthetic Recovery Time after Colorectal Surgery with N-acetyl-cysteine Infusion / 대한마취과학회지

BACKGROUND: The gut is an important area for inflammatory responses. Gut manipulation during open laparotomy compared with laparoscopic surgery, increases the inflammatory responses. Laparoscopic assisted colectomy (LC) with less bowel manipulation might minimize the inflammatory responses and oxidative stress, and offer a faster postanesthetic recovery than an open colectomy (OC). This study evaluated the effect of N-acetyl-cysteine (NAC), an antioxidant, on the recovery after colectomy. METHODS: 116 colorectal tumor patients were reviewed retrospectively. The patients were divided into 3 groups; LC by surgeon A (A - L), OC by surgeon A (A - O) and OC by surgeon B (B - O). The postanesthetic recovery scores (PARS) were compared. In the prospective randomized controlled trial, the colorectal tumor patients were assigned to one of four groups; laparoscopic assisted colectomy (L - N) with NAC infusion (L + N), open colectomy (O - N) with NAC infusion (O + N). In the NAC groups, NAC (5 mg/kg/h) was infused after intubation to extubation. The PARS were compared. RESULTS: In the retrospective study, the time to reach 10 points, which satisfies the discharge criteria in the PACU, was significantly lower in the A-L group than in the other groups. In the prospective study, the time to 10 points was shorter in the O + N group than in the O-N group. NAC offered no added benefits to the L + N and L-N groups. CONCLUSIONS: NAC offered faster recovery in the OC group but not in the LC group.

Quantitative Analysis of Secreted Catecholamines from Chromaffin Cells in Vitro and in Vivo / 대한마취과학회지

BACKGROUND: Adrenal medullary transplants into the subarachnoid space have been demonstrated to reduce pain sensitivity. This analgesia most likely results from the release of neuroactive substances, particularly catecholamines and opioid peptides from the transplanted cells into spinal cord. METHODS: Isolated bovine chromaffin cells were encapsulated with alginate and poly-L-lysine prior to implantation into rat's subarachnoid space to protect them from host immune system. And then catecholamines from encapsulated chromaffin cells were measured quantitatively in vitro by High Performance Liquid Chromatograph. The animals were randomized into 2 groups, one of which received microencapsulated chromaffin cells and the other empty capsules. The effects of such implants were evaluated on the pain behavior resulting from a chronic constriction injury of the rat sciatic nerve for 30 days. RESULTS: Catecholamine concentration in cerebrospinal fluid (CSF) was analyzed. Data (mean SD) are considered significant at P <0.05 (ANOVA for repeated measure and Dunnett's test). Continuous release of catecholamine and met-enkephalin with responsiveness to nicotine stimulation was measured from encapsulated cells in vitro. A significant reduction of allodynic response to acetone evaporation was observed in the animals implanted with cell loaded capsules compared to control animals with empty capsules. Catecholamine concentration in CSF was higher in the cell loaded capsule group. There were no complications related to implantation. CONCLUSION: We found that encapsulated chromaffin cells released continuously catehcolamines and opioids peptides in vitro and in the CSF. Those results may prove chromaffin cell's anagesic effect indirectly.

Microencapsulated Bovine Adrenal Medullary Chromaffin Cells Transplanted into Rat Spinal Cord Alleviated Cold Allodynia / 대한마취과학회지

BACKGROUND: The intrathecal grafting of adrenal chromaffin cells as a potential analgesic source, to delivery analgesic substances such as catecholamines and opioid peptides, is known to be effective at treating acute and chronic pain in several animal pain models. We tested whether the intrathecal implantation of encapsulated bovine chromaffin cells reduces cold allodynia in a rat model of neuropathic pain induced by chronic constriction injury of the sciatic nerve. METHODS: Bovine adrenal medullary chromaffin cells microencapsulated in sodium alginate-poly-l-lysin-alginate (APA) were implanted into the subarachnoid space of rats (n = 10) and foot cold sensitivity was investigated using an acetone test. At the end of the study, histology and capsule catecholamine production were evaluated. RESULTS: A significant reduction in cold allodynia was observed in animals implanted with chromaffin cells. In addition, the suppression of cold allodynia was reversed by naloxone. Abundant clusters of viable chromaffin cells stained with neutral red, were observed in the retrieved implants and after nicotine stimulation, and catecholamine was quantified. An ultrastructural study showed no fibrotic reaction against capsules, or disorganised capsules. CONCLUSIONS: These results suggest that intrathecal encapsulated chromaffin cells act as "mini pumps", which continuously deliver analgesic substances and produce analgesia in this chronic pain model of nerve injury-without immunosuppressant.

Comparison of Changes in Carbon Dioxide Absorption during Transperitoneal Laparoscopic Surgery and Intraperitoneal Laparoscopic Surgery / 대한마취과학회지

BACKGROUND: Transperitoneal laparoscopy for renal surgery is now a common procedure. Previous studies have suggested that retroperitoneal laparoscopy is associated with greater carbon dioxide absorption. We compared carbon dioxide absorption and hemodynamic variables in patients undergoing transperitoneal laparoscopy for renal or adrenal surgery with that of patients undergoing intraperitoneal laparoscopy for colon surgery. METHODS: Thirty two patients undergoing laparoscopic surgery were divided into laparoscopic renal surgery group (n = 16) and laparoscopic colon surgery group (n = 16). We measured hemodynamic changes and arterial blood gases before CO2 insufflation, 10 minutes, 70 minutes after insufflation and 30 minutes after exsufflation in each groups. RESULTS: There was no significant difference in carbon dioxide absorption in patients who underwent transperitoneal laparoscopy compared to intraperitoneal laparoscopy at any interval. CONCLUSIONS: In contrast to previous reports, our study suggests that transperitoneal laparoscopy is not associated with greater carbon dioxide absorption compared to intraperitoneal laparoscopy.

The Influence of Bispectral Index and Hemodynamics during Propofol TCI with Intravenous Injection of Lidocaine / 대한마취과학회지

BACKGROUND: Lidocaine has been used for attenuating cardiovascular responses to endotracheal intubation and thought to have the sedative effect. The sedative effect of lidocaine has not been known well. The BIS (bispectral index) has been used an indicator of the sedative state and has been considered to be related to anesthetic agents and noxious stimulus. The purpose of this study is to evaluate sedative and cardiovascular effects of lidocaine during TCI (target controlled infusion) of propofol by monitoring BIS and hemodynamics. METHODS: Fifty ASA patient status 1 and 2, aged from 20 to 65 years patients (n = 50, 2 groups) undergoing elective surgeries with general anesthesia. These patients were randomly allocated to group C or L. Patients in Group L received 1.5 mg/kg injection and 40microgram/kg/min infusion of lidocaine. Patients in Group C received normal saline. The BIS, blood pressure and heart rate were mesasured before injection of drug, 1, 2 minute after injection of drug, just before intubation, 1, 2, 5 and 10 min after intubation. RESULTS: The BIS of group L more decreased than group C at 1, 2, 5 and 10 min after endotracheal intubation. The blood pressure and heart rate did not show any differences between two groups. CONCLUSIONS: Intravenous injection of lidocaine reduced BIS. Lidocaine had sedative effects under propofol target controlled infusion. But Cardiovascular variables of this study failed to show any differences between two groups (P < 0.05).

The Hemodynamic Effects of Sevoflurane Anesthesia During Induction and Early Maintenance for Coronary Artery Bypass Graft Surgery: Compared with Fentanyl-Midazolam/Isoflurane Anesthesia / 대한마취과학회지

BACKGROUND: Sevoflurane is the most recently available volatile agent which permits the rapid induction with its nonirritant nature. The goal of this study was to compare the hemodynamic responses of sevoflurane induction and maintenance period with those of fentanyl-midazolam/isoflurane anesthesia for CABG. METHODS: Twenty-eight patients who underwent CABG were given anesthesia, and were randomly assigned to receive sevoflurane (Sevo Group, n = 15) or fentanyl-midazolam/isoflurane (Iso-Fent Group, n = 13), as induction and maintenance agents. In the Sevo group, anesthesia was induced with two or three deep breaths of 7.5% sevoflurane, and maintained with 2% sevoflurane after intubation. The Iso-Fent Group received fentanyl 5microgram/kg and midazolam 0.2 mg/kg with oxygen for induction and maintained with 0.8% isoflurane and 5microgram/kg/hr of fentanyl by infusion. All were given vecuronium as a muscle relaxant. Cardiac and oxygen metabolic profiles were measured before and 10 minutes after tracheal intubation. RESULTS: Before induction, there was no difference between Sevo and Iso-Fent group in terms of cardiac and oxygen metabolic profiles. After intubation, mean arterial pressure, mean pulmonary arterial pressure, pulmonary capillary wedge pressure, heart rate and mixed venous oxygen saturation in the Sevo group were higher than in the Iso-Fent group (P < 0.05). The ST-segment changes in the EKG monitoring was unremarkable during anesthesia induction in either group. CONCLUSIONS: For the induction and early anesthesia maintenance in patients undergoing CABG surgery, sevoflurane may be a substitute for fentanyl-midazolam/isoflurane without any significant hemodynamic changes.

The Prevention of Rocuronium Injection Pain by Lidocaine Pretreatment / 대한마취과학회지

BACKGROUND: Intravenous injection of rocuronium produces intense discomfort at the site of injection in conscious patients. We compared the efficacy of normal saline, and of lidocaine 10 mg, 20 mg, 30 mg, and 40 mg pretreatment at preventing pain caused by injecting rocuronium. METHODS: 250 ASA physical status Iand II patients, aged 18 to 70 years, were randomized into 5 groups of 50 patients in a double blinded prospective study. After tourniquet application on the forearm, the control group received 2 ml of normal saline as a pretreatment. The other 4 groups received lidocaine 10 mg (Lido10 group), lidocaine 20 mg (Lido20 group), lidocaine 30 mg (Lido30 group), or lidocaine 40 mg (Lido40 group) as a pretreatment in a 2 ml solution. The tourniquet was released after 20 seconds and rocuronium was injected over 10 seconds. The patients were then observed and asked if they had pain in, and responses were assessed. Local signs (i.e. erythema, venous sequelae) on the arm where the rocuronium had been injected were recorded immediately after the injection and 12 h later, after recovery from anesthesia. RESULTS: 44 patients (88%) in the control group, 35 (70%) in the Lido10 group, 32 (64%) in the Lido20 group, 23 (46%) in the Lido30 group, and 16 (32%) in the Lido40 group reported pain. The medial pain score was 1.92 +/- 1.04 in the control group, 1.12 +/- 0.96 in the Lido10 group, 0.92 +/- 0.85 in the Lido20 group, 0.52 +/- 0.61 in the Lido30 group, and 0.34 +/- 0.48 in the Lido40 group. Moderate to severe pain was observed in 33 patients (66%) in the control group, 16 (32%) in the Lido10 group, 12 (24%) in the Lido20 group, 3 (6%) in the Lido30 group, and none (0%) in the Lido40 group. No local signs were observed. CONCLUSIONS: Pretreating with lidocaine at 10, 20, 30 or 40 mg reduced the incidence and severity of pain on injecting rocuronium, and the higher dose was more effective.

Predicting Recovery from Deep Neuromuscular Block by Rocuronium During Sevoflurane versus Propofol Anesthesia / 대한마취과학회지

BACKGROUND: The use of volatile anesthetics for the maintenance of anesthesia can enhance the action and prolong the duration of non-depolarizing muscle relaxants. The objective of this study was to establish the relation between the post tetanic count (PTC) and the time to reappearance of the first response (T1) by train-of-four (TOF) nerve stimulation following rocuronium 0.6 mg/kg (ED95 X 2) during sevoflurane versus propofol anesthesia. METHODS: Fifty adult patients were randomized to one of two groups, which had anesthesia maintained with sevoflurane or propofol. During sevoflurane or propofol anesthesia, neuromuscular block was monitored by mechanography using TOF stimulation every 12 s. At 6 min intervals, a tetanic stimulation (50 Hz) was applied for 5 s, which was preceded and followed by a 15 s period of 1 Hz single stimulation until the reappearance of T1. RESULTS: First responses to PTS appeared earlier in the propofol group (12.5 +/- 5.2 min) than in the sevoflurane group (16.6 +/- 7.4 min), and first responses to TOF stimulation also occurred significantly sooner in the propofol group (24.8 +/- 5.1 min) than in the sevoflurane group (32.6 +/- 8.9 min). The interval between the appearance of PTC and T1 was shorter in the propofol than in the sevoflurane group. CONCLUSIONS: We conclude that sevoflurane prolonged recovery from deep neuromuscular block by rocuronium as compared to propofol. The PTC method can be used to predict the time to first response to TOF nerve stimulation during intense rocuronium induced neuromuscular blockade.

Do Microencapsulated Bovine Adrenal Medullary Chromaffin Cells Transplanted in Rats' Spinal Cord Produce Analgesic Effects? / 대한마취과학회지

BACKGROUND: Pain remains the chief complaint that brings patients to physician's office, despite recent insights into underlying mechanism and the identification of potential new therapeutic targets. In recent years, however, with the development of molecular biology cell transplantation gives us a new chance for treating intractable chronic pain. The major purpose of the present study was to determine if the chromaffin cells that were encapsulated with 1.3% (w/v) sodium alginate-poly-l-lysine-alginate (APA) had robust analgesic effects in the spinal atlanto-occipital subarachnoid space even without nicotine stimulation. METHODS: In order to determine whether microencapsulated bovine adrenal medullary chromaffin cells transplanted in the spinal cord can produce analgesic effects, we microencapsulated adrenal medullary chromaffin cells with APA and implanted them into the subarachnoid space of rats' (n = 10) spinal cord, and investigated the hot sensitivity of rats' hind-paw by a light-beam test. RESULTS: It was found that compared with the control group, hot response latency of the group which received adrenal medullary chromaffin cells increased from the 12th day and the analgesic efficacy was maintained for at least 75 days. CONCLUSIONS: Microencapsulated bovine adrenal medullary chromaffin cells transplanted in the rats' spinal cord may provide a permanent and locally available source of neuropeptides for the relief of intractable pain. Furthermore, these kinds of analgesic effect were produced without any stimulation such as nicotine.

Comparison of Clinical Effect of Low Dose Bupivacaine Added with Fentanyl and Conventional Dose Bupivacaine in Spinal Anesthesia for a Transurethral Resection of the Prostate / 대한마취과학회지

BACKGROUND: The combination of local anesthetics and opioids in the spinal anesthesia has a synergic analgesic effect. Therefore, we compared intraoperative conditions and clinical effects of low dose (5 mg) bupivacaine added with fentanyl versus a conventional dose(10 mg) of bupivacaine in spinal anesthesia for a transurethral resection of the prostate (TURP). METHODS: Forty five ASA class 1 and 2 patients scheduled for a TURP were randomly divided into three groups. Group B (n = 15) received bupivacaine 10 mg, group BF (n = 15) received bupivacaine 5 mg added with fentanyl 20microgram, and group BFE received bupivacaine 5 mg added with fentanyl 20microgram and 0.2 mg epinephrine. Blood pressure and heart rate were recorded every 5 minutes before and after spinal anesthesia. Sensory blockade was measured by a pin-prick test and motor blockade was evaluated by the Bromage motor scale. Side effects including pruritus, nausea, vomiting, respiratory depression, and intraoperative pain were observed. RESULTS: The duration of sensory and motor blockade in group BF was significantly shorter than in group B and group BFE (P<0.05). Without statistical significance, hypotension (6.7%) and bradycardia (13.3%) were observed in group B and pruritus (26.7%) and nausea (13.3%) occurred in all patients who received fentanyl. CONCLUSIONS: The addition of fentanyl 20microgram to low dose bupivacaine 5 mg resulted in short lasting motor and sensory block, compared with conventional dose bupivacaine 10 mg. Therefore, we concluded that the clinical application of this method could provide adequate analgesia with early discharge and no serious side effects for TURP patients.

Tissue Engineered Cartilage Formation using Human Hyaline Chondrocytes and Elastic Chondrocytes

The purpose of this study was to evaluate the influence of different types of PLGA scaffolds on the formation of human auricular and septal cartilages. The scaffolds were formed in tubular shape from 110,000 g/mol PLGA (poly lactic glycolic acid) and 220,000 g/mol one. Elastic cartilage was taken from the ear of a patient aged under 20 years old and hyaline cartilage from the nasal septum. The chondrocytes cells were then isolated by Klausburn method. After second passages, the chondrocytes were seeded on the PLGA scaffolds followed by in vitro culture for one week. The cells-PLGA scaffold complex was implanted at the back of nude mouses for 8 weeks. The tissue engineered cartilages were separated from nude mouse and examined histologically after staining with the Hematoxylin Eosin and Verhoeff. The formation of extracellular matrix and the porosity of the scaffolds were examined by scanning electron microscopy. The pores were well formed and uniformly distributed in both 110,000 g/mol and 220,000 g/mol PLGA scaffolds. The extracellular matrix was formed better in 110,000 g/mol PLGA compared to 220,000 g/mol one. And hyaline cartilage was proliferated better in vitro culture than elastic cartilage. After 8 weeks in vivo culture, cartilage was well formed with 110,000 g/mol PLGA, however lumen was collapsed. In contrast with 220,000 g/mol PLGA scaffold, neocartilage was formed in minimal amount while the architecture of scaffold was well preserved. Elastic cartilage seems to be better than hyaline one in terms of neocartilage formation. From the analysis after Verhoeff staining the cartilages, the neocartilage from elastic cartilage was proved to be elastic cartilage. In summary, there was no significant difference between elastic cartilage and hyaline cartilage in their morphologies, proliferation rates and the degree of cartilage formation since they were tissue engineered, however marked difference was found in neocartilage formation and preservation of scaffold architecture between 110,000 g/mol PLGA scaffold and 220,000 one. From the present findings, it is concluded that the influence of scaffold materials is significantly higher than that of different types of cells on the formation of new tissues.

The Evaluation of Topical Anesthetic Effects of a Liposome Encapsulated Mixture of Local Anesthetics (Lipo-MLA) / 대한마취과학회지

BACKGROUND: This study investigated the effect of topical analgesic effects of a liposome encapsulated mixture of local anesthetics (lipo-MLA) compared with EMLA. METHODS: 3% lipo-MLA (0.5% tetracaine base, 2.5% lidocaine base) and 5% lipo-MLA (1% tetracaine base, 4% lidocaine base) were encapsulated into liposomal vesicles made with egg yolk phosphatidylcholine, cholesterol and phosphatidyldioleoyl. 3% lipo-MLA and EMLA were applied to volunteers' forearms bilaterally with and without an occlusive dressing. The topical anesthetic effects of the lipo-MLA and EMLA as a control were evaluated by the pinprick test in 28 adult volunteers after 60 minutes of application. The analgesic influence of the concentration of local anesthetics was also compared with 3% and 5% lipo-MLA under a non-occlusive dressing. RESULTS: Analgesic effects of the 3% lipo-MLA were similar with EMLA under an occlusive dressing for 60 minutes. In addition, analgesic effects of the 3% lipo-MLA under a non-occlusive dressing were more potent than EMLA. Lipo-MLA under a non-occlusive dressing showed more potent analgesic effect than lipo-MLA under an occlusive dressing. 5% lipo-MLA was more potent than 3% lipo-MLA under a non-occlusive dressing. CONCLUSIONS: Lipo-MLA has more potent analgesic effects than EMLA without an occlusive dressing and 5% lipo-MLA is more potent than 3% lipo-MLA. Therefore, lipo-MLA appeared to be an improved topical analgesic formulation which provides a more potent and convenient topical application.

Analgesic Effect of Transplanted Adrenal Medullary Chromaffin Cells in Rats Spinal Cord / 대한마취과학회지

BACKGROUND: Despite of numerous researches on the mechanisms and new therapeutic methods of chronic pain, patients are still suffering even with the help of opioids. In recent years, however, with the development of molecular-biology cell transplantation gives us a new chance for treating intractable chronic pain. The major purpose of the present study was to determine if the chromaffin cells have robust analgesic effects in the spinal atlanto-occipital subarachnoid space even without nicotine stimulation. METHODS: In order to determine whether cultured bovine adrenal medullary chromaffin cells transplanted in the spinal cord can produce analgesic effects, we purified adrenal medullary chromaffin cells and implanted them into the subarachnoid space of rats' (n = 10) spinal cord without immunosuppression, and investigated the hot sensitivity of rats' hind-paw by a light-beam test. RESULTS: It was found that compared with the control group, hot response latency of the group which received adrenal medullary chromaffin cells had increased at 14 days and the analgesic efficacy was maintained for at least 3 months. CONCLUSIONS: Adrenal medullary chromaffin cells transplanted in the rats' spinal cord may provide a permanent and locally available source of neuropeptides for the relief of intractable pain. Furthermore, these kinds of analgesic effect even produced without any stimulation such as nicotine.

Spectral Analysis of EEG with Reversible Middle Cerebral Artery Occlusion in Rats / 대한마취과학회지

BACKGROUND: An adequate cerebral blood flow is critical in maintaining obligatory metabolic function of cerebral neurons. The occlusion of these flows may cause impairment of the cellular metabolic function. Therefore, the early detection and treatment of this can have a direct impact on the prognosis. This study is designed to determine the changes of electroencephalography (EEG) waves with power spectral analysis during and after cerebral blood flow impairment with reversible middle cerebral artery occlusion in rats. METHODS: Five rats were anesthetized with ketamine and the left middle cerebral artery was reversibly occluded. Neurologic deficit and the EEG were evaluated. The principal procedure consisted of the following: All branches of the external carotid artery and pterygopalatine artery of the internal carotid artery were interrupted. At this point, the internal carotid artery is the only branch of the common carotid artery. Afterwards, the external carotid artery was interrupted. A 4-0 monofilament nylon suture, its tip rounded, was introduced into the external carotid artery lumen and advanced to block blood flow into the middle cerebral artery. The suture was withdrawn to permit reperfusion after 2 hours. Monitoring of the EEG was performed before the occlusion, after 10, 30, 60, and 120 minutes of occlusion, and after 10, 30 and 60 minutes of reperfusion. The neurologic findings were scored on a five-point scale. RESULTS: In the spectral power analysis of EEG, the total power of the EEG amplitude decreased significantly after left middle cerebral artery occlusion, increased after 30 minutes of occlusion, and decreased significantly after reperfusion. The theta, alpha and beta waves changed significantly after occlusion. Theta and beta waves were reversed slowly. After reperfusion, theta and alpha waves decreased significantly. CONCLUSIONS: It is suggested that the spectral analysis of an EEG is useful in early detection and treatment of ischemia in patients with cerebrovascular disease.

Effects of Vasodilators on Coronary Vasospasm Induced by Endothelin in the Isolated Perfused Rat Heart / 대한마취과학회지

BACKGROUND: An endothelium derived vasoconstrictor peptide, endothelin, has been shown to be a potent coronary vascular constrictor. In the clinical settings of angina or myocardial ischemia, the endothelial injury of coronary artery can stimulate the endothelin production. In this study, the authors assessed the response to endothelin of the coronary artery in isolated rat heart and compared the relative effects of three vasodilators (nifedipine, adenosine, nitroprusside) on coronary vasospasm which was induced by endothelin. METHODS: The isolated rat heart preparations (Langendorff model) were obtained from fourty male Sprague-Dawley rats (350-400 gm). Preparations were perfusated with Krebs-Hanseleit solution of (mM): NaCl 115, NaHCO3 25, KCl 4.7, CaCl2 2H2O 2.5, MgCl2 6H2O 1.2, KH2PO4 1.2, glucose 10. The perfusate was maintained at 37oC and aerated with carbogen (oxygen 95% and carbon dioxide 5%). The coronary perfusion was maintained at 80 cmH20 pressure and Latex balloon was positioned in left ventricle. After the preparations were stabilized, endothelin (10(-9) M) was added to perfusate for 5 minutes and followed the perfusion without vasodilators (control, n = 10) or with vasodilators (nifedipine, adenosine and nitroprusside 10(-7) M to 10(-6) M, n = 10 each) for 45 minutes. The left ventricular developed pressure (LDP) and heart rate (HR) was recorded and the coronary effluent (VOL) was collected to measure the unit volume and the CPK isoenzyme (CK-MB). Effects of the interventions were assessed using analysis of variance. All values are presented as means +/- SE. RESULTS: VOL, HR and VDP were significantly reduced after infusion of 10(-9) M endothelin in 3 and 5 minutes. VOL was recovered efficiently after infusion of three vasodilators. Adenosine and nitroprusside groups showed superior recovery in the changes of rate pressure product (RPP) than in nifedipine group, which was significant reduced in VDP. CONCLUSIONS: These results suggest that in the situation of endothelin induced severe coronary vasospasm, adenosine and nitroprusside effectively reversed the coronary vasospasm without severe myocardial depression.