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.

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.

EEG and Topographic Frequency Analysis of Laser Therapeutic Efficacy in Occipital Headaches / 대한마취과학회지

BACKGROUND: It is controversial that an electrocardiography (EEG) is valuable in evaluation of patients with headache. The purpose of this study was to determine whether EEG brain mapping can be a useful indicator for evaluating the analgesic efficacy of treatment on the patient with an occipital headache. METHODS: We did an EEG on 20 patients with occipital headaches at the peri-laser application period. The laser was radiated for 3 minutes a third of the total distance from the external occipital protuberance to the mastoid process on the superior nuchal line. An EEG was taKen before laser radiation as control use, and at 10, 30 and 60 minutes after laser radiation by 32 channel electrodes (international 10 20 system). The EEG mapping was red for the high electric potential and blue for the low electric potential. RESULTS: Compared with control group, the alpha wave increased significantly in parieto-occipital and occipital region at 60 minutes after laser radiation (P < 0.05). DarK red color was increased especially in occipital region at 60 minutes after laser radiation, compared with EEG mapping before laser radiation. Good and Fair improvements were observed in 55% of the patients with occipital headaches. CONCLUSIONS: We conclude that EEG can be a valuable indicator in the evaluation of analgesic efficacy of treatment in the patients suffering from occipital headaches. Pain scores were assessed by the patient with the visual analogue scale (VAS).

Artificial Retina Mimbrane Assembly Utilzing Intelligent Materials: Biocompatibility and Electorphysiologic Features

In recent studies there have been various attempts at replacing a damaged retina with an artificial one. This paper outlines the assembly of an artificial retina membrane by incorporating a photorective protein bacteriorhodopsin into an electrochemically syntheszed conducting polymer polypyrrole. An electrophysiologic test was conducted to evaluate the photoresponsiveness of the bacteriorhodopsin and rabbit eyes were used to examine the biocompatibility of the artificial retina. The electrophysiologic test analyzed both wave forms and amplitudes obtained by photostimulating the artificial retina membrane with various light intensites(0.2, 2, 20J). In the biocompatibility test, the artificial membrane was inserted into the anterior chambers(4 eyes) and vitreous cavities(8 eyes) of rabbits. The condition of the eyes was then observed for one month. At the end of the first moonth, the eyes were enucleated and a histological examination was carried out. The electrophysiologic study displayed negative reflection waves, which are characteristic in rhodpsin, and their amplitudes showed a correspondign increase with stronger light intensities. The results of the biocompatibility test demonstrated that inflammatory reactions were not prominent in either the anterior chambers or the vitreous cavities during the first month and the histological examinations revealed no specific findings. In conclusion, a membrane assembled utilizing an electroactive polymer and a phocial retina.