Soon Ho Cheong

Ex vivo organ culture of adipose tissue for in situ mobilization of adipose-derived stem cells and defining the stem cell niche

In spite of the advances in the knowledge of adipose‐derived stem cells (ASCs), in situ location of ASCs and the niche component of adipose tissue (AT) remain controversial due to the lack of an appropriate culture system. Here we describe a fibrin matrix‐supported three‐dimensional (3D) organ culture system for AT which sustains the ASC niche and allows for in situ mobilization and expansion of ASCs in vitro. AT fragments were completely encapsulated within the fibrin matrix and cultured under dynamic condition. The use of organ culture of AT resulted in a robust outgrowth and proliferation in the fibrin matrix. The outgrown cells were successfully recovered from fibrin by urokinase treatment. These outgrown cells fulfilled the criteria of mesenchymal stem cells, adherence to plastic, multilineage differentiation, and cell surface molecule expression. In vitro label retaining assay revealed that newly divided cells during the culture resided in interstitium between adipocytes and capillary endothelial cells. These interstitial stromal cells proliferated and outgrew into the fibrin matrix. Both in situ mobilized and outgrown cells expressed CD146 and α‐smooth muscle actin (SMA), but no endothelial cell markers (CD31 and CD34). The structural integrity and spatial approximation of CD31−/CD34−/CD146+/SMA+ interstitial stromal cells, adipocytes, and capillary endothelial cells were well preserved during in vitro culture. Our results suggest that ASCs are natively associated with the capillary wall and more specifically, belong to a subset of pericytes. Furthermore, organ culture of AT within a fibrin matrix‐supported 3D environment can recapitulate the ASC niche in vitro. J. Cell. Physiol. 224: 807–816, 2010.

Comparison of the effects of acetaminophen to ketorolac when added to lidocaine for intravenous regional anesthesia

Background This study was done to evaluate the effect on pain relief when acetaminophen was added to lidocaine for intravenous regional anesthesia (IVRA). Methods Sixty patients undergoing hand or forearm surgery received IVRA were assigned to three groups: Group C received 0.5% lidocaine diluted with 0.9% normal saline to a total volume of 40 ml (n = 20), Group P received 0.5% lidocaine diluted with intravenous acetaminophen 300 mg to a total volume of 40 ml (n = 20) and Group K received 0.5% lidocaine diluted with 0.9% normal saline plus ketorolac 10 mg made up to a total volume of 40 ml (n = 20). Sensory block onset time, tourniquet pain onset time, which was defined as the time from tourniquet application to fentanyl administration for relieving tourniquet pain and amount of analgesic consumption during surgery were recorded. Following deflation of tourniquet sensory recovery time, postoperative pain and quantity of analgesic uses in post-anesthesia care unit were assessed. Results Sensory block onset time was shorter in Group P compared to Group C (P < 0.05). Tourniquet pain onset time was delayed in Group P when compared with group C (P < 0.05). Postoperative pain and analgesic consumption were reduced in Group P and Group K compared to Group C (P < 0.001). Conclusions The addition of acetaminophen to lidocaine for IVRA shortens the onset time of sensory block and delays tourniquet pain onset time, but not with ketorolac. Both acetaminophen and ketorolac reduce postoperative pain and analgesic consumption.

Effects of genetic polymorphisms of OPRM1, ABCB1, CYP3A4/5 on postoperative fentanyl consumption in Korean gynecologic patients.

OBJECTIVE Fentanyl, a μ-opioid receptor agonist, is a substrate of P-glycoprotein. Its metabolism is catalyzed by CYP3A4 and CYP3A5. The aim of this study was to investigate the association between postoperative fentanyl consumption and genetic polymorphisms of μ-opioid receptor (OPRM1), ABCB1 (gene encoding P-glycoprotein), CYP3A4 and CYP3A5 in Korean patients. METHODS 196 female patients scheduled to undergo total abdominal hysterectomy or laparoscopic assisted vaginal hysterectomy under general anesthesia were enrolled in this study. Intravenous patient-controlled analgesia with fentanyl was provided postoperatively. Cumulative fentanyl consumption was measured during the first 48 hours postoperatively. The severity of pain at rest was assessed with the visual analogue scale. OPRM1 118A>G, ABCB1 2677G>A/T, ABCB1 3435C>T, CYP3A4*18 and CYP3A5*3 variant alleles were genotyped. The effects of genetic and non-genetic factors on fentanyl requirements were evaluated with multiple linear regression analysis. RESULTS The 24-hour cumulative fentanyl doses were significantly associated with pain core, weight and type of surgery (p < 0.05). The 48-hour cumulative fentanyl doses were significantly associated with pain score, type of surgery and history of PONV or motion sickness (p < 0.05). Genetic polymorphisms were not associated with fentanyl requirements. CONCLUSION In Korean gynecologic patients, no association was found between genetic factors and postoperative fentanyl consumption.

Does dexmedetomidine reduce postoperative pain after laparoscopic cholecystectomy with multimodal analgesia

Background Pain after laparoscopy is multifactorial and different treatments have been proposed to provide pain relief. Multimodal analgesia is now recommended to prevent and treat post-laparoscopy pain. Dexmedetomidine, an α2 agonist, has well-known anesthetic and analgesic-sparing effects. We evaluated the analgesic effect of perioperative dexmedetomidine infusion during laparoscopic cholecystectomy with multimodal analgesia. Methods Forty-two patients aged 20 to 60 years old were allocated randomly into one of 2 groups (n = 21, in each). All patients underwent laparoscopic cholecystectomy under multimodal analgesia. The patients in group P received dexmedetomidine 1 µg/kg during 10 min before induction and then 0.5 µg/kg/h continuously until the removal of the gall bladder while the patients in the group C received saline by the same methods as group P. Total analgesic consumption and VAS score were recorded for the first 24 hr. Results There were no significant differences in VAS scores between group P and group C during 24 hr after laparoscopic cholecystectomy. VAS scores of group P were lower than that of group C during the 1st hr after operation. The amount of ketorolac required during the 24 hr after the operation was significantly less in group P compared to group C. Conclusions The administration of dexmedetomidine during laparoscopic cholecystectomy with multimodal analgesia has minimal benefits on the reduction of the postoperative pain score. The amount of ketorolac requirements during 24 hr after the operation showed significant difference. Dexmedetomidine might be helpful for the postoperative pain after laparoscopic cholecystectomy with multimodal analgesia.

Fibrin matrix-supported three-dimensional organ culture of adipose tissue for selective outgrowth, expansion, and isolation of adipose-derived stem cells

Conventional systems for isolating adipose-derived stem cells (ASC) require enzymatic digestion of adipose tissue (AT), followed by monolayer culture to the enrich the stem cell population. However, these systems are hindered by low cell yields and a lack of reproducibility. The present study was aimed at developing a unique strategy for isolating ASC based on fibrin matrix-supported three-dimensional (3-D) organ culture of native AT. Furthermore, we tried to optimize the fibrin composition by adjusting the fibrinogen and thrombin concentrations to allow rapid outgrowth and proliferation of ASC in the 3-D fibrin matrix. Human cutaneous AT fragments were encapsulated within the fibrin matrix to construct a 3-D environment and cultured under dynamic conditions. During in vitro culture the fibrin matrix provided physical support for the AT and also allowed selective outgrowth of ASC from embedded AT fragments. In situ expanded outgrown cells were recovered from the fibrin matrix by selective fibrinolysis and propagated under monolayer culture conditions. The cultured cells fulfilled the following criteria for ASC: adhesion to culture plastic, multipotent differentiation, correct immunophenotypic profile. Fibrin matrix-supported 3-D organ culture produced ASC that with high competency in terms of growth and differentiation capabilities, and resulted in a larger and more consistent cell yield than obtained with conventional culture systems. The fibrinogen and thrombin concentrations inversely affected spreading, migration, and ASC outgrowth from native AT. Our results indicate that this 3-D organ culture system for AT can be used as an efficient and reproducible method for ASC isolation.

Blind oral endotracheal intubation of rats using a ventilator to verify correct placement

Endotracheal intubation in rats is challenging due to difficulties visualizing the epiglottis and vocal cords. No visualization of these structures results in repeated intubation attempts which can cause trauma to the oral cavity and/or oesophagus, and death of the animal due to respiratory failure. Here, we describe a simple blind oral tracheal intubation technique in the rat that decreases the frequency of repeated intubations using an intubation device that comprises a 16 G intravenous catheter and a modified 18 G epidural needle, and a rodent ventilator. The epidural needle is bent in such a way that it curves in conformity with the rats oral airway in order to direct the catheter into the larynx, and the rodent ventilator is used to verify its correct placement. The first attempt success rate of endotracheal intubation using the blind oral tracheal intubation technique with a rodent ventilator was greater than the first attempt success rate using the blind oral tracheal intubation technique without using a rodent ventilator. Although this method is a simple modification of a previously described method of blind oral endotracheal intubation, our method is easy to learn, inexpensive and does not require specialized equipment.

Analgesic effect of preoperative versus intraoperative dexamethasone after laparoscopic cholecystectomy with multimodal analgesia

Background Pain after laparoscopy is multifactorial and different treatments have been proposed to provide pain relief. Multimodal analgesia is now recommended to prevent and treat post-laparoscopy pain. Dexamethasone is effective in reducing postoperative pain. The timing of steroid administration seems to be important. We evaluated the analgesic efficacy of preoperative intravenous dexamethasone 1 hour before versus during laparoscopic cholecystectomy with multimodal analgesia. Methods One hundred twenty patients aged 20 to 65 years old were allocated randomly into one of three groups (n = 40, in each). The patients in the group N received normal saline 1 hour before induction and after the resection of gall bladder. The patients in the group S1 received dexamethasone 8 mg 1 hour before induction and normal saline after the resection of gall bladder. The patients in the group S2 received normal saline 1 hour before induction and dexamethasone 8 mg after the resection of gall bladder. Results VAS scores of group S1 and S2 were lower than that of group N during 48 hours after laparoscopic cholecystectomy. There were no significant differences of VAS scores between the group S1 and the group S2. The analgesic consumption of group S1 and S2 were significantly lower than that of group N. Conclusions A single dose of dexamethasone (8 mg) intravenously given 1 hour before induction or during operation was effective in reducing postoperative pain after laparoscopic cholecystectomy with multimodal analgesia. The analgesic efficacy of preoperative intravenous dexamethasone 1 hour before versus during surgery was not significantly different.

Brief report: the effect of suggestion on unpleasant dreams induced by ketamine administration.

The use of ketamine may be associated with the recall of unpleasant dreams after sedation. We hypothesized that a positive suggestion before sedation could reduce the incidence of ketamine-induced unpleasant dreams. To test this hypothesis, we randomized 100 patients receiving sedation with ketamine for their procedure into 2 groups with 1 group having an anesthesiologist provide a mood-elevating suggestion to the patient before ketamine administration (suggestion group), whereas in the control group no suggestion was provided. Patients were provided with a pleasantness/unpleasantness scale to rate “the overall mood of the dream” as very unpleasant (grade 1), quite unpleasant (grade 2), neither or mixed (grade 3), quite pleasant (grade 4), and very pleasant (grade 5). In those patients who lost consciousness, the frequencies of grades 1, 2, 3, 4, and 5 were 0%, 0%, 46%, 24%, and 30% in the suggestion group and were 6%, 2%, 70%, 12%, and 10%, respectively, in the control group (P = 0.01). In the intent-to-treat population the overall frequency between groups was very similar. This study implies that when administering ketamine as part of a sedation regimen, positive suggestion may help reduce the recall of unpleasant dreaming.

The combination of sugammadex and neostigmine can reduce the dosage of sugammadex during recovery from the moderate neuromuscular blockade

Background Sugammadex is a novel neuromuscular reversal agent, but its associated hypersensitivity reaction and high cost have been obstacles to its widespread use. In the interest of reducing the necessary dosage of sugammadex, the reversal time of the combined use of sugammadex and neostigmine from moderate neuromuscular blockade were investigated. Methods The patients enrolled ranged in age from 18 to 65 years old with American Society of Anesthesiologists class 1 or 2. The subjects were randomly assigned into one of the four groups (Group S2, S1, SN, and N; n = 30 per group). The reversal agents of each groups were as follows: S2 - sugammadex 2 mg/kg, S1 - sugammadex 1 mg/kg, SN - sugammadex 1 mg/kg + neostigmine 50 µg/kg + glycopyrrolate 10 µg/kg, N - neostigmine 50 µg/kg + glycopyrrolate 10 µg/kg. The time to recovery of the train-of-four (TOF) ratio was checked in each group. Results The time to 90% recovery of TOF ratio was 182.6 ± 88.9, 371.1 ± 210.4, 204.3 ± 103.2, 953.2 ± 379.7 sec in group S2, S1, SN and N, respectively. Group SN showed a significantly shorter recovery time than did group S1 and N (P < 0.001). However, statistically significant differences between the S2 and SN groups were not be observed (P = 0.291). No hypersensitivity reactions occurred in all groups. Conclusions For the reversal from rocuronium-induced moderate neuromuscular blockade, the combined use of sugammadex and neostigmine may be helpful to decrease the recovery time and can also reduce the required dosage of sugammadex. However, the increased incidence of systemic muscarinic side effects must be considered.

Prevention of pain during injection of microemulsion propofol: application of lidocaine mixture and the optimal dose of lidocaine

Background Similar to lipid emulsion propofol, microemulsion propofol also causes a high incidence of pain during intravenous injection. Various methods have been used to minimize the incidence and severity of pain on injection of lipid emulsion propofol. In this study, we investigated the effect of a lidocaine mixture on pain induced by microemulsion propofol injection, and sought to determine the optimal dose of lidocaine that could reduce pain on injecting a propofol-lidocaine mixture. Methods One hundred sixty (n = 160) patients of American Society of Anesthesiologists physical status class I or II were randomly allocated to four groups: Group A, control; Group B, 20 mg lidocaine; Group C, 30 mg lidocaine; Group D, 40 mg lidocaine. In each patient, pain on microemulsion propofol solution injection was graded as none, mild, moderate, or severe. Results The incidence of pain in groups A, B, C, and D was 97.5%, 80%, 65%, and 50%, respectively. Increasing the lidocaine dose significantly reduced pain (P < 0.05). One patient in Group D (2.5%) had moderate to severe pain, which was significantly lower than groups B (42.5%) and C (32.5%) (P < 0.05). Conclusions The lidocaine and propofol mixture is effective in alleviating pain associated with microemulsion propofol injection. Within this dose range and in this patients population, increasing lidocaine dosage significantly reduced pain during injection of microemulsion propofol.