The Effect of Plasma Treatment of Poly (Lactic-co-Glycolic)(PLGA) Scaffold on Adhesion and Bioactivity of Cultured Chondrocytes

The advantages of wielding synthetic polymer are that the pore size, physical strength and chemical composition can be easily controlled. However, the synthetic polymer has hydrophobic character and low affinity to cells and other bio molecules. This study was performed to investigate the effect of plasma glow's discharge on the surface modification of poly(lactic-co-glycolic acid)(PLGA) sponge on the adhesion and bio-activity of chondrocytes in vitro culture. PLGA sponges(lactic acid: glycolic acid = 85 : 15, pore size=200 - 300 mrcro m, dimension=15 x 2 mm) were prepared. The experimental group(n=8) was treated with a radiofrequency plasma glow-discharge(acrylic acid and oxygen: 50 W, 0.2 torr for 30 seconds) but the control group (n=8) was treated with nothing. 1 x 10(6)ml/20 microliter of P3 chondrocytes from rabbit ears were used for seeding. Eight hours after cell seeding, the total DNA amount of chondrocytes attached to the PLGA and the changes of actin were evaluated under a confocal microscope. Type I and II collagen expression were detected by RT-PCR three weeks after seeding for an evaluation of phenotypic maintenance. The total DNA amount of attached chondrocytes was remarkably increased in the experimental group(p < 0.05). After scrutinizing with a confocal microscope, the actin of cells was more spread out and finely arranged in the experimental group than in the control group. Both types of collagen expression were significantly increased in their assigned groups. Plasma treatment of the PLGA sponge could increase the adhesion property of chondrocytes, and provide suitable environment for maintaining the phenotype of chondrocytes.

Revascularization of Inferior Epigastric Islasnd Flap woth Limited Bed Contact

Island flaps have been widely used for the management of soft tissue defects in reconstructive surgery. The necrosis of the flap has been a catastrophe in clinical fields. It is well known that revascularization to the flap after ligation of its pedicle comes from the recipient bed and flap margins. The authors investigated the effects of the ischemic recipient bed on island flap survival after the ligation of its pedicle in the rats. One hundred and thirty inferior epigastric island flaps were divided into three groups (Group I, Group II, and Group III) according to the degree (0%,20%, and 60%) of interruption of contact of flap with the recipient bed, respectively. In Group I,the vascular pedicles were ligated before and on the 0, 2nd, 3rd, 4th and 5th days after flap elevation, and in Group II & III, the vascular pedicles were ligated on the 2nd, 3rd, 4th and 5th days after flap elevation. Flap survival was assessed on the 3rd day after pedicle ligation. Microangiographic studies were also performed on the 3rd day after pedicle ligation to study revascularization within the flap and the change of blood vessels around the flap margins. The results were as follows: 1. Flap survival was increased significantly in the flaps with pedicle ligation on the 4th and 5th postoperative days compared to those at the 2nd and 3rd postoperative days. 2. From the 3rd postoperative day, flap survival was not influenced significantly by the degree of limited bed contact and the date of pedicle ligation. 3. In spite of limited bed contact, the flap will likely survive with abundant revascularization from the flap margins. In conclusion, the flaps with limited bed contact were revascularized significantly from the flap margin by the 3rd postoperative day.

Lacrimal canalicular reconstruction with various materials

This retrospective clinical study consists of 27 patients with lacrimal canalicular injury caused by various accidents and which were reconstructed with various materials in the department of plastic surgery at Catholic University Medical College from December 1987 to July 1996. These 27 patients were followed up at least 6 months after the canalicular reconstruction and their medical records were reviewed and analysed retrospectively in order to obtain the clinical pattern and understand the therapeutic results. The statistical items were the age and sex distribution, the causes of injury, the prevalent site of injury, the reconstruction materials, the duration of intubation and the results of treatment. The following results are obtained: 1. Males were more dominant than females by 4.4 : 1. 2. The patient age was from 6 to 73 years old and the prevalent age groups were the third and fourth decades(55.5%). 3. The most common cause of canalicular injury was the violence(29.6%) and was followed by traffic accident. 4. The left canaliculi, especially inferior canaliculi, was the prevalent injury site. 5. Regardless of the materials(P.V.C. tube, nylon and silicone tube) used in canalicular reconstruction, the longer duration of intubation was obtained the better result of treatment. 6. So the silicone tube with stainless steel(C-line canaliculus intubation set) was relatively inert and less complicating, it could be maintained more longer and had better results than other materials such as P.V.C. tube and nylon.

THE EFFECT OF COLLAGEN SUBSTRATE IN CULTURE MEDIUM ON DNA AND PROTEIN SYNTHESIS OF DERMAL FIBROBLASTS

Collagen is the major component of scar tissue. Considerable progress of fibroblast growth kinetics and of collagen synthesis has been achieved in the past decade. We have been interested in fibroblasts activities as they are expressed by cells cultured in collagen substrate. This study is to examine the effects of collagen substrate and peptide growth factors In culture medium on DNA and protein synthesis of human dermal fibroblasts. Collagen, interleukin-1(IL-1) and transforming growth factor-beta(TGF-beta) were added to fibroblast culture media according to the designed experiment model and DNA and protein synthesis were measured by [3H]-thymidine, [3H]-leucine, and [3H]-proline incorporation method. The morphological features of fibroblasts were observed by light microscope. The results were as follows ; 1) There were significant decreases of DNA and protein synthesis of cultured fibroblasts in the presence of collagen substrate compared with those in Control groups(p<0.01). 2) DNA and protein synthesis were decreased as dose dependant manner of collagen density in culture media. 3) Morphological features of fibroblasts became less stellate and flat, more spindle-like in the presence of collagen. 4) In responsiveness to IL-1, collagen non-treated groups responded to IL-1 but collagen treated groups were unresponsive to IL-1 (P<0.05). 5) Cells In collagen non-treated groups responded to TGF-beta as dose-related manner(P<0.01). Collagen treated groups desponded to TGF-beta but did not show TGF-beta dose-dependant relationship. In Conclusion, collagen substrate in the culture medium could lower the DNA and protein synthesis of fibroblasts. Cells in collagen substrate were unresponsive or less responsive to peptide growth factors than those in non-collagen substrate.