rhBMP-2-Conjugated Three-Dimensional-Printed Poly(L-lactide) Scaffold is an Effective Bone Substitute

BACKGROUND@#Bone growth factors, particularly bone morphogenic protein-2 (BMP-2), are required for effective treatment of significant bone loss. Despite the extensive development of bone substitutes, much remains to be desired for wider application in clinical settings. The currently available bone substitutes cannot sustain prolonged BMP-2 release and are inconvenient to use. In this study, we developed a ready-to-use bone substitute by sequential conjugation of BMP to a three-dimensional (3D) poly(L-lactide) (PLLA) scaffold using novel molecular adhesive materials that reduced the operation time and sustained prolonged BMP release. @*METHODS@#A 3D PLLA scaffold was printed and BMP-2 was conjugated with alginate-catechol and collagen. PLLA scaffolds were conjugated with different concentrations of BMP-2 and evaluated for bone regeneration in vitro and in vivo using a mouse calvarial model. The BMP-2 release kinetics were analyzed using ELISA. Histological analysis and microCT image analysis were performed to evaluate new bone formation. @*RESULTS@#The 3D structure of the PLLA scaffold had a pore size of 400 lm and grid thickness of 187–230 lm. BMP-2 was released in an initial burst, followed by a sustained release for 14 days. Released BMP-2 maintained osteoinductivity in vitro and in vivo. Micro-computed tomography and histological findings demonstrate that the PLLA scaffold conjugated with 2 lg/ml of BMP-2 induced optimal bone regeneration. @*CONCLUSION@#The 3D-printed PLLA scaffold conjugated with BMP-2 enhanced bone regeneration, demonstrating its potential as a novel bone substitute.

Development and Effects of a Person-Centered Fall Prevention Program for Older Adults with Dementia in Long-Term Care Hospitals: For Older Adults with Dementia and Caregivers in LongTerm Care Hospitals

Purpose@#This study examined the effects of a person-centered fall prevention program for older adults with dementia in long-term care hospitals. @*Methods@#A nonequivalent control group pretest-posttest design was used. The study sample included 42 older adults with dementia (experimental group: 21, control group: 21) and 42 caregivers (experimental group: 21, control group: 21). The program comprised 48 sessions held over 12 weeks and included exercise intervention with resistance and balance, dance walking (45~60 min, three times/week), cognitive and emotional intervention (35~50 min, once per week), and person-centered fall prevention education (10 min, once per week). The program for caregivers consisted of six educational sessions (i.e., fall prevention competency enhancement and person-centered care strategy education, 80 min, once per week) for six weeks. Data were collected before participation and 12 weeks after program completion from February 18 to May 12, 2019. Data analysis was conducted using the chi-square test, t-test, and Mann―Whitney U test with SPSS/WIN 21.0. @*Results@#The experimental group of older adults with dementia showed significant improvement in physical and cognitive functions, and a decrease in depression, and behavioral and psychological symptoms, when compared with the control group. caregivers in the experimental group exhibited significant improvement in fall-related knowledge and person-centered care of older adults with dementia compared to the control group. @*Conclusion@#The study findings indicate that this program was effective as a nursing intervention for fall prevention among older adults with dementia in long-term care hospitals.

Fabrication and Characterization of Graphene Oxide-Coated Plate for Efficient Culture of Stem Cells

BACKGROUND@#For stem cell applications in regenerative medicine, it is very important to produce high-quality stem cells in large quantities in a short time period. Recently, many studies have shown big potential of graphene oxide as a biocompatible substance to enhance cell growth. We investigated if graphene oxide-coated culture plate can promote production efficiency of stem cells. @*METHODS@#Three types of graphene oxide were used for this study. They are highly concentrated graphene oxide solution, single-layer graphene oxide solution, and ultra-highly concentrated single-layer graphene oxide solution with different single-layer ratios, and coated on cell culture plates using a spray coating method. Physiochemical and biological properties of graphene oxide-coated surface were analyzed by atomic force microscope (AFM), scanning electron microscope (SEM), cell counting kit, a live/dead assay kit, and confocal imaging. @*RESULTS@#Graphene oxide was evenly coated on cell culture plates with a roughness of 6.4 * 38.2 nm, as measured by SEM and AFM. Young’s Modulus value was up to 115.1 GPa, confirming that graphene oxide was strongly glued to the surface. The ex vivo stem cell expansion efficiency was enhanced as bone marrow-derived stem cell doubling time on the graphene oxide decreased compared to the control (no graphene oxide coating), from 64 to 58 h, and the growth rate increased up to 145%. We also observed faster attachment and higher affinity of stem cells to the graphene oxide compared to control by confocal microscope. @*CONCLUSION@#This study demonstrated that graphene oxide dramatically enhanced the ex vivo expansion efficiency of stem cells. Spray coating enabled an ultra-thin coating of graphene oxide on cell culture plates. The results supported that utilization of graphene oxide on culture plates can be a promising mean for mass production of stem cells for commercial applications.

Fabrication and Characterization of Graphene Oxide-Coated Plate for Efficient Culture of Stem Cells

BACKGROUND@#For stem cell applications in regenerative medicine, it is very important to produce high-quality stem cells in large quantities in a short time period. Recently, many studies have shown big potential of graphene oxide as a biocompatible substance to enhance cell growth. We investigated if graphene oxide-coated culture plate can promote production efficiency of stem cells. @*METHODS@#Three types of graphene oxide were used for this study. They are highly concentrated graphene oxide solution, single-layer graphene oxide solution, and ultra-highly concentrated single-layer graphene oxide solution with different single-layer ratios, and coated on cell culture plates using a spray coating method. Physiochemical and biological properties of graphene oxide-coated surface were analyzed by atomic force microscope (AFM), scanning electron microscope (SEM), cell counting kit, a live/dead assay kit, and confocal imaging. @*RESULTS@#Graphene oxide was evenly coated on cell culture plates with a roughness of 6.4 * 38.2 nm, as measured by SEM and AFM. Young’s Modulus value was up to 115.1 GPa, confirming that graphene oxide was strongly glued to the surface. The ex vivo stem cell expansion efficiency was enhanced as bone marrow-derived stem cell doubling time on the graphene oxide decreased compared to the control (no graphene oxide coating), from 64 to 58 h, and the growth rate increased up to 145%. We also observed faster attachment and higher affinity of stem cells to the graphene oxide compared to control by confocal microscope. @*CONCLUSION@#This study demonstrated that graphene oxide dramatically enhanced the ex vivo expansion efficiency of stem cells. Spray coating enabled an ultra-thin coating of graphene oxide on cell culture plates. The results supported that utilization of graphene oxide on culture plates can be a promising mean for mass production of stem cells for commercial applications.

Preparation and Characterization of Human Adipose Tissue-Derived Extracellular Matrix, Growth Factors, and Stem Cells: A Concise Review

BACKGROUND: Human adipose tissue is routinely discarded as medical waste. However, this tissue may have valuable clinical applications since methods have been devised to effectively isolate adipose-derived extracellular matrix (ECM), growth factors (GFs), and stem cells. In this review, we analyze the literature that devised these methods and then suggest an optimal method based on their characterization results. METHODS: Methods that we analyze in this article include: extraction of adipose tissue, decellularization, confirmation of decellularization, identification of residual active ingredients (ECM, GFs, and cells), removal of immunogens, and comparing structural/physiological/biochemical characteristics of active ingredients. RESULTS: Human adipose ECMs are composed of collagen type I–VII, laminin, fibronectin, elastin, and glycosaminoglycan (GAG). GFs immobilized in GAG include basic fibroblast growth factor (bFGF), transforming growth factor beta 1(TGF-b1), insulin like growth factor 1 (IGF-1), vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF), BMP4 (bone morphogenetic protein 4), nerve growth factor (NGF), hepatocyte growth factor (HGF), and epithermal growth factor (EGF). Stem cells in the stromal-vascular fraction display mesenchymal markers, self-renewal gene expression, and multi-differentiation potential. CONCLUSION: Depending on the preparation method, the volume, biological activity, and physical properties of ECM, GFs, and adipose tissue-derived cells can vary. Thus, the optimal preparation method is dependent on the intended application of the adipose tissue-derived products.

Full Thickness Skin Expansion ex vivo in a Newly Developed Reactor and Evaluation of Auto-Grafting Efficiency of the Expanded Skin Using Yucatan Pig Model

BACKGROUND: Skin grafts are required in numerous clinical procedures, such as reconstruction after skin removal and correction of contracture or scarring after severe skin loss caused by burns, accidents, and trauma. The current standard for skin defect replacement procedures is the use of autologous skin grafts. However, donor-site tissue availability remains a major obstacle for the successful replacement of skin defects and often limits this option. The aim of this study is to effectively expand full thickness skin to clinically useful size using an automated skin reactor and evaluate auto grafting efficiency of the expanded skin using Yucatan female pigs. METHODS: We developed an automated bioreactor system with the functions of real-time monitoring and remote-control, optimization of grip, and induction of skin porosity for effective tissue expansion. We evaluated the morphological, ultra-structural, and mechanical properties of the expanded skin before and after expansion using histology, immunohistochemistry, and tensile testing. We further carried out in vivo grafting study using Yucatan pigs to investigate the feasibility of this method in clinical application. RESULTS: The results showed an average expansion rate of 180%. The histological findings indicated that external expansion stimulated cellular activity in the isolated skin and resulted in successful grafting to the transplanted site. Specifically, hyperplasia did not appear at the auto-grafted site, and grafted skin appeared similar to normal skin. Furthermore, mechanical stimuli resulted in an increase in COL1A2 expression in a suitable environment. CONCLUSION: These findings provided insight on the potential of this expansion system in promoting dermal extracellular matrix synthesis in vitro. Conclusively, this newly developed smart skin bioreactor enabled effective skin expansion ex vivo and successful grafting in vivo in a pig model.

Optimization of Recombinant Human Platelet-Derived Growth Factor-BB Encapsulated in Poly (Lactic-co-Glycolic Acid) Microspheres for Applications in Wound Healing

Growth factors play multiple and critical roles in wound repair processes. Platelet-derived growth factor (PDGF) is a potent growth factor that is particularly important in the early inflammatory phase of wound healing. In order to extend the half-life of PDGF, polymeric encapsulation is used. In the current study, Poly (lactic-co-glycolic acid) (PLGA) microspheres containing recombinant human (rh) PDGF-BB were prepared to prolong the effectiveness of this growth factor. PLGA microspheres were optimized using a modified w/o/w-double-emulsion/solvent evaporation method by changing the processing conditions of stirring speed and emulsifier (polyvinyl alcohol) concentration. Microspheres prepared using the optimized method released rhPDGF-BB for up to three weeks. An in vitro migration assay showed a significant decrease in the wound area in cells treated with rhPDGF-BB microspheres compared to control cells. These findings demonstrate the potential of rhPDGF-BB encapsulated in microspheres to enhance wound healing.

Rapid Expansion and Auto-Grafting Efficiency of Porcine Full Skin Expanded by a Skin Bioreactor Ex Vivo

Full skin auto-grafts are required for reconstruction of skin burns and trauma scars. However, currently available clinical approaches such as sheet skin graft, mesh skin grafts, artificial skin graft, and in vivo skin expansion have limitations due to their potential danger for secondary damage and scar formation at the donor site, and discomfort during skin expansion. We developed an advanced bioreactor system and evaluated its function in skin expansion using porcine full skin. The reactor was designed as a pneumatic cylinder type, was programmed to adjust the pressure and the operating time. The system was composed of culture chamber unit, environmental control unit, and monitoring unit. Skins were expanded at 200 kPa pneumatic force and the expanded skins were analyzed by immunohistochemistry and histology. Furthermore we carried out auto-grafting experiment of the expanded skins in vivo using Yucatan pigs and skins were harvested and histologically analyzed after 8 weeks. The results showed that the bioreactor expanded skins to 160% in 4 hours. Histological analysis of the expanded skins revealed that epidermal cells and dermal fibroblasts were viable and remained integrity. The results of auto-grafting experiment indicated that fibrosis and scars were not detected in the grafted skins. This study demonstrates that the newly developed skin bioreactor enabled to obtain large sized full skin rapidly and successful grating.

Pre-Clinical Efficacy and Safety Evaluation of Human Amniotic Fluid-Derived Stem Cell Injection in a Mouse Model of Urinary Incontinence

PURPOSE: Stem cell-based therapies represent new promises for the treatment of urinary incontinence. This study was performed to assess optimized cell passage number, cell dose, therapeutic efficacy, feasibility, toxicity, and cell trafficking for the first step of the pre-clinical evaluation of human amniotic fluid stem cell (hAFSC) therapy in a urinary incontinence animal model. MATERIALS AND METHODS: The proper cell passage number was analyzed with hAFSCs at passages 4, 6, and 8 at week 2. The cell dose optimization included 1x10(4), 1x10(5), and 1x10(6) cells at week 2. The in vivo cell toxicity was performed with 0.25x10(6), 0.5x10(6), and 1x10(6) cells at weeks 2 and 4. Cell tracking was performed with 1x10(6) cells at weeks 2 and 4. RESULTS: The selected optimal cell passage number was smaller than 6, and the optimal cell dose was 1x10(6) for the mouse model. In our pre-clinical study, hAFSC-injected animals showed normal values for several parameters. Moreover, the injected cells were found to be non-toxic and non-tumorigenic. Furthermore, the injected hAFSCs were rarely identified by in vivo cell trafficking in the target organs at week 2. CONCLUSION: This study demonstrates for the first time the pre-clinical efficacy and safety of hAFSC injection in the urinary incontinence animal model and provides a basis for future clinical applications.

Applicability and Safety of in Vitro Skin Expansion Using a Skin Bioreactor: A Clinical Trial

BACKGROUND: Tissue expansion is an effective and valuable technique for the reconstruction of large skin lesions and scars. This study aimed to evaluate the applicability and safety of a newly designed skin expanding bioreactor system for maximizing the graft area and minimizing the donor site area. METHODS: A computer-controlled biaxial skin bioreactor system was used to expand skin in two directions while the culture media was changed daily. The aim was to achieve an expansion speed that enabled the skin to reach twice its original area in two weeks or less. Skin expansion and subsequent grafting were performed for 10 patients, and each patient was followed for 6 months postoperatively for clinical evaluation. Scar evaluation was performed through visual assessment and by using photos. RESULTS: The average skin expansion rate was 10.54%+/-6.25%; take rate, 88.89%+/-11.39%; and contraction rate, 4.2%+/-2.28% after 6 months. Evaluation of the donor and recipient sites by medical specialists resulted in an average score of 3.5 (out of a potential maximum of 5) at 3 months, and 3.9 at 6 months. The average score for patient satisfaction of the donor site was 6.2 (out of a potential maximum of 10), and an average score of 5.2 was noted for the recipient site. Histological examination performed before and after the skin expansion revealed an increase in porosity of the dermal layer. CONCLUSIONS: This study confirmed the safety and applicability of the in vitro skin bioreactor, and further studies are needed to develop methods for increasing the skin expansion rate.

Exhaled Breath Analysis System based on Electronic Nose Techniques Applicable to Lung Diseases / 한양의대학술지

Smell used to be a common diagnostic tool in medicine, and physicians were trained to use their sense of smell during their medical training. Latterly, odor disgnostics have been relegated to secondary status as a diagnostic method. Array-based gas sensors ("Electronic Nose") now offer the potential of a robust analytical approach to exhaled breath analysis for medical use. Many diseases are accompanied by characteristic odor, and their recognition can provide diagonostic clues, guide the laboratory evaluation, and affect the choice of immediate therapy. We are developing an intelligent sensor system for non-invasive health care monitoring combined laboratory based sensor module, pattern recognition subsystem and non-invasive sampling of volatile emitted from a patient into a highly intelligent sensor system that allows the rapid processing of these samples. It is capable to assist early and rapid disgnosis of changes in state of patient, and aid decision making by medical personnel in the treatment of such patients. In this paper, we introduce exhaled breath analysis for potential primary lung disease screening using electronic nose system incorporating an automated solid-phase microextraction (SPME) desorption to enable the system to be used. Aiming to increase the sensitivity, SPME preconcentration is used for sampling of headspace air and the response of sensor module to variable concentration of volatile emitted from SPME fiber is evaluated. The initial result shows the distinguished difference between the lung cancer patients and healthy normal individuals according to the analysis of the respective expiratory gases.

RET Fusion Genes in Korean Non-Small Cell Lung Cancer

Recently, rearranged during transfection (RET) fusions have been identified in approximately 1% of non-small cell lung cancer (NSCLC). To know the prevalence of RET fusion genes in Korean NSCLCs, we examined the RET fusion genes in 156 surgically resected NSCLCs using a reverse transcriptase polymerase chain reaction. Two KIF5B-RET fusions and one CCDC6-RET fusion were identified. All three patients were females and never smokers with adenocarcinomas. RET fusion genes were mutually exclusive from EGFR, KRAS mutations and EML4-ALK fusion. RET fusion genes occur 1.9% (3 of 156) of surgically treated NSCLC patients in Koreans.

Telomerase Activity and the Risk of Lung Cancer

Telomerase play a key role in the maintenance of telomere length and chromosome integrity. We have evaluated the association between telomerase activity and the risk of lung cancer in peripheral blood. Telomerase activity in peripheral blood mononuclear cells was measured by a PCR-designed telomeric repeat amplification protocol in 63 lung cancer patients and 190 healthy controls that were matched for age, gender, and smoking status. Telomerase activity was significantly lower in the lung cancer patients than in controls (mean +/- standard deviation; 1.32 +/- 1.65 vs 2.60 +/- 3.09, P < 1 x 10(-4)). When telomerase activity was categorized into quartiles based on telomerase activity in the controls, the risk of lung cancer increased as telomerase activity reduced (Ptrend = 1 x 10(-4)). Moreover, when the subjects were categorized based on the median value of telomerase activity, subjects with low telomerase activity were at a significantly increased risk of lung cancer compared to subjects with high telomerase activity (adjusted odds ratio = 3.05, 95% confidence interval = 1.60-5.82, P = 7 x 10-4). These findings suggest that telomerase activity may affect telomere maintenance, thereby contributing to susceptibility to lung cancer.

Polymorphisms in Apoptosis-Related Genes and TP53 Mutations in Non-Small Cell Lung Cancer

Apoptosis plays an essential role in the elimination of mutated or transformed cells from the body. Therefore, polymorphisms of apoptosis-related genes may lead to an alteration in apoptotic capacity, thereby affecting the occurrence of TP53 mutations in lung cancer. We investigated the relationship between potentially functional polymorphisms of apoptosis-related genes and TP53 mutations in non-small cell lung cancer (NSCLC). Twenty-seven single nucleotide polymorphisms in 20 apoptosis-related genes were genotyped by a sequenome mass spectrometry-based genotyping assay in 173 NSCLCs and the associations with TP53 mutations in the entire coding exons (exons 2-11), including splicing sites of the gene, were analyzed. None of the 27 polymorphisms was significantly associated with the occurrence of TP53 mutations. This suggests that apoptosis-related genes may not play an important role in the occurrence of TP53 mutations in lung cancer.

Fabrication of an alpha-lipoic acid-eluting poly-(D,L-lactide-co-caprolactone) cuff for the inhibition of neointimal formation

The purpose of this study was to develop a novel polymer cuff for the local delivery of alpha-lipoic acid (ALA) to inhibit neointimal formation in vivo. The polymer cuff was fabricated by incorporating the ALA into poly-(D,L-lactide-co-caprolactone) 40:60 (PLC), with or without methoxy polyethylene glycol (MethoxyPEG). The release kinetics of ALA and in vitro degradation by hydrolysis were analyzed by HPLC and field emission scanning electron microscopy (FE-SEM), respectively. In vivo evaluation of the effect of the ALA-containing polymer cuff was carried out using a rat femoral artery cuff injury model. At 24 h, 48% or 87% of the ALA was released from PCL cuffs with or without MethoxyPEG. FE-SEM results indicated that ALA was blended homogenously in the PLC with MethoxyPEG, whereas ALA was distributed on the surface of the PLC cuff without MethoxyPEG. The PLC cuff with MethoxyPEG showed prolonged and controlled release of ALA in PBS, in contrast to the PLC cuff without MethoxyPEG. Both ALA-containing polymer cuffs had a significant effect on the inhibition of neointimal formation in rat femoral artery. Novel ALA-containing polymer cuffs made of PLC were found to be biocompatible and effective in inhibiting neointimal formation in vivo. Polymer cuffs containing MethoxyPEG allowed the release of ALA for one additional week, and the rate of drug release from the PLC could be controlled by changing the composition of the polymer. These findings demonstrate that polymer cuffs may be an easy tool for the evaluation of anti-restenotic agents in animal models.

The Development of Biodegradable Intrascleral Implant for Slow Releasing of Triamcinolone Acetonide

PURPOSE: In order to treat inflammatory and proliferative disorders of the posterior segment of the eye, the authors evaluated the use of a biodegradable intrascleral implant for slow release of triamcinolone acetonide (TA). METHODS: The intrascleral implant (1 mm thick and 3 mm in diameter) was made of alginic acid and PLA (poly (D, L-lactide)) containing 4 mg of TA. In vitro release of TA was evaluated by HPLC. To evaluate in vivo release of TA, the implant was placed into a scleral pocket in 18 rabbit eyes and the concentrations of TA in the aqueous humor, vitreous, and retina-choroid-sclera were measured by HPLC at 1, 2, 4, 8, and 12 weeks after implantation. The toxicity and biocompatibility of the implant were evaluated by slit lamp examination, IOP, electroretinogram, and light microscopy. RESULTS: In vitro study demonstrated that the implant released TA in controlled manner for at least 8 months. The TA detected in the vitreous after 8 to 12 weeks and was not detected in retina-choroid-sclera at 8 weeks after implantation. The TA was not detected in aqueous humor. No significant toxicity to the retina was observed. CONCLUSIONS: These results suggest that the intrascleral implant of TA could be a promising system for the delivery of steroids to the posterior segment of eye in cases of inflammatory or proliferative disorders of posterior segment.

Formation of an Intestine-Cartilage Composite Graft for Tracheal Reconstruction / 대한흉부외과학회지

BACKGROUND: Tracheal transplantation is necessary in patients with extensive tracheal stenosis, congenital lesions and other oncologic conditions but bears many critical problems compared to other organ transplantations. The purpose of this study was to develop intestine-cartilage composite grafts for potential application in tracheal reconstruction by free intestinal graft. MATERIAL AND METHOD: Hyaline cartilage was harvested from trachea of 2 weeks old New Zealand White Rabbits. Chondrocytes were isolated and cultured for 8 weeks. Cultured chondrocytes were seeded in the PLGA scaffolds and mixed in pluronic gel. Chondrocyte bearing scaffolds and gel mixture were embedded in submucosal area of stomach and colon of 3 kg weighted New Zealand White Rabbits under general anesthesia. 10 weeks after implantation, bowels were harvested for evaluation. RESULT: We identified implantation site by gross examination and palpation. Developed cartilage made a good frame for shape memory. Microscopic examinations included special stain s howed absorption of scaffold and cartilage formation even though it was not fully matured. CONCLUSION: Intestine-cartilage composite graft could be applicable in the future as tracheal substitute and should be further investigated.

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.

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.

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.