Young Soo Nam

Study on gelatin-containing artificial skin: I. Preparation and characteristics of novel gelatin-alginate sponge.

An absorbable sponge, composed of gelatin and alginate, was prepared by new crosslinking method that improved the efficiency of crosslinking. The crosslinking degree was characterized by trinitrobenzenesulfonic acid (TNBS) assay. A water uptake ability test, in vitro drug release and collagenase degradation tests, and an in vivo animal test were employed to confirm the applicability of this gelatin-alginate sponge as a wound dressing material. As the alginate content in the sponge increased, the porosity increased, resulting in an enhanced water uptake ability. Sponges loaded with silver sulfadiazine or gentamicin sulfate slowly released drugs for up to four days. The crosslinked sponge resisted in vitro collagenase digestion for up to three days. An in vivo animal test using witar rat showed rather good wound healing effect of gelatin-alginate sponge containing AgSD than vaseline gauze in our full-thickness skin defect model.

Studies on gelatin-containing artificial skin: II. Preparation and characterization of cross-linked gelatin-hyaluronate sponge

This study was conducted to develop a new sponge type of biomaterial to be used for either wound dressing or scaffold for tissue engineering. We were able to prepare an insoluble matrix composed of gelatin and sodium hyaluronate (HA) by dipping the soluble sponge into 90% (w/v) acetone/water mixture containing a small amount of cross-linking agent, 1-ethyl-3-3-dimethylaminoproplycarbodiimide hydrochloride, EDC. To characterize the sponge, Fourier-transformed infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and Instron analysis were performed. The obtained results indicate that the chemically cross-linked sponge shows a cross-linking degree of 10-35%, a mean pore size of 40-160 microm, porosity of 35-67%, and a tensile strength of 10-30 gf/cm(2). Especially, the porosity measured by image analysis showed a tendency to increase with HA content, resulting in an increased water uptake. The resistance to collagenase degradation in vitro increased for up to 2 days. Silver sulfadiazine (AgSD)-impregnated gelatin-HA sponge was also prepared and compared with conventional vaseline gauze by applying it onto a dorsal skin defect of wistar rat for 5, 12, and 21 days. Histological results showed an enhancement of wound healing in AgSD-impregnated gelatin-HA sponge.

Study on gelatin-containing artificial skin IV: a comparative study on the effect of antibiotic and EGF on cell proliferation during epidermal healing

Gelatin-hyaluronate sponge with and without antibiotic and epidermal growth factor (EGF) were prepared and compared. Four types of sponges were applied on the full-thickness dorsal skin defect of Wistar rat. The effects of antibiotic and EGF in gelatin-hyaluronate sponge on wound healing were investigated by light microscopy and image analyzer at postoperative days of 5, 12 and 21. An immunohistochemical technique, employing PC10, a monoclonal antibody against proliferating cell nuclear antigen (PCNA) was applied to wounded tissue sections. The number of PC10-positive cells was very high for the sponge with EGF at postoperative day 5, then gradually decreased with time. Also we found that antibiotics restrained the cell proliferation during the migratory phase. The sponge with both antibiotic and EGF showed good wound healing performances on the whole for a healing period. The epithelium was regenerated fast with EGF-impregnated sponges at day 5, but each sample had nearly the same length of regenerated epithelium at day 12.

Release Kinetics and in vitro Bioactivity of Basic Fibroblast Growth Factor: Effect of the Thickness of Fibrous Matrices

In this study, we fabricated non-woven matrices using blends of polycaprolactone and gelatin with various spinning volumes to control the immobilized heparin content, which was ultimately intended to increase the immobilization efficiency of bFGF. The amount of bFGF on the heparin conjugated fibrous matrices depended on the thicknesses of the swollen matrices ranging from 35.4 ± 6.5 to 162.3 ± 14.0 ng and ≈90% of the bFGF was gradually released over a period of up to 56 d. The released bFGF enhanced the proliferation of human umbilical vein endothelial cells and human mesenchymal stem cells. In conclusion, our heparin-conjugated fibrous matrices have the potential to be used as a growth factor delivery system in tissue engineering applications.

Biofeedback therapy after perineal rectosigmoidectomy or J pouch procedure.

The aim of this study was to determine the outcome and to identify possible predictors of success for biofeedback therapy after perineal rectosigmoidectomy (PRS) or coloanal or ileoanal J pouch. A retrospective chart review of all patients with electromyography-based biofeedback therapy due to fecal incontinence after PRS or a J pouch procedure was undertaken. Follow-up was obtained by telephone survey. Fourteen patients (4 men and 10 women) were included in this study. In the 9 patients after PRS, the frequency of daily bowel movements was 3.6 2.8 preoperatively, 4.1 3.2 prebiofeedback, and 2.2 - 1.3 postbiofeedback (P < .05). The frequency of daily incontinent episodes was reduced from 2.4 2.2 preoperatively and 2.0 + 1.9 prebiofeedback to 0.26 0.3 postbiofeedback (P< .05). The incontinence scores decreased from 17 3.1 preoperatively to 16 + 2.1 prebiofeedback and to 8.2 5 postbiofeedback (P < .001). At a follow-up of 15.8 7.1 months, 5 patients after the J pouch had decreased daily bowel frequency from 6.6 4.2 prebiofeedback to 3.3 2 postbiofeedback and 3.1 2 at follow-up (P < .05). The frequency of daily incontinent episodes was reduced from 1.9 1.3 prebiofeedback to 0.9 0.7 postbiofeedback to 0.7 0.8 at followup (P < .05). The incontinence scores decreased from 13.4 2.7 prebiofeedback to 8.8 5.1 postbiofeedback to 6.8 5.5 at follow-up (P < 0.05). In both groups, the postbiofeedback incontinence score correlated with the prebiofeedback incontinence score. Furthermore, there was no correlation between outcome and age, interval between surgery and biofeedback therapy, frequency of biofeedback sessions, or manometry results in either group. Biofeedback therapy is an effective option for patients with fecal incontinence after perineal rectosigmoidectomy or colonic or ileal J pouch.

The applicability of laparoscopic gastrectomy in the surgical treatment of giant duodenal ulcer perforation.

Purpose: The present study aims to provide an applicability of laparoscopic gastrectomy used in the treatment of giant duodenal ulcer perforation. Methods: Between July 2010 and April 2011, laparoscopic distal gastrectomy with ROUX-EN-Y gastrojejunostomy and truncal vagotomy was performed in consecutive 5 patients with giant duodenal ulcer perforation. Results: There was no conversion to open surgery. There was no severe postoperative complication. The days of normalization of leukocytosis were 3, 1, 2, 2, and 5, respectively. The times to first flatus were postoperative days 2, 3, 5, 2, and 3. The days of commencement of a soft diet were postoperative days 5, 5, 6, 5, and 5. They were discharged on postoperative days 9, 11, 20, 10, and 11. Conclusions: We suggest that laparoscopic surgery may be a good surgical method to improve surgical outcomes and is worth a try in experts.

Two-day fasting prior to intestinal ischemia-reperfusion injury on bacterial translocation in rats.

ABSTRACT Purpose: The aim of this study is to verify the effect of two-day fasting prior to intestinal ischemia-reperfusion (I/R) injury on bacterial translocation (BT). Materials and Methods: Mail Sprague–Dawley rats were divided into four groups: group 1, control rats that underwent sham operation only; group 2, rats fasted for two days prior to sham operation; group 3, rats that underwent occlusion of mesenteric vessels for 30 min followed by reperfusion for 4 hr; and group 4, rats fasted for two days prior to the same intestinal I/R injury as in group 3. In all groups, E. coli labeled with 99mTc were inoculated into the terminal ileum. Two hr after inoculation of E. coli, the rats were killed. A segment of ileum was obtained for histological examination and samples of mesenteric lymph nodes (MLNs), liver, lung, blood, and spleen were obtained for radioactivity determination. Results: There were no significant differences in the intestinal mucosa and radioactivity of all samples between groups 1 and 2. Group 3 showed significantly shorter mucosa and villi, and higher radioactivity of samples, except for MLNs, compared to group 1. Group 4 showed similar mucosa and villi, but significantly higher radioactivity of samples, except for MLNs, compared to group 3. Conclusion: Two-day fasting without I/R injury does not cause mucosal change and BT, but in cases following intestinal I/R injury, two-day fasting increases the susceptibility of BT to systemic organs in rats.

Clinical usefulness of preoperative and postoperative chest computed tomography for colorectal cancer.

Purpose This research sought to identify the utility value of chest computed tomography (CT) when it comes to the diagnosis of lung metastasis in cases of colorectal cancer. Methods From September 2004 to January 2008, 266 patients who were treated for colorectal cancer at Department of Surgery, Hanyang University College of Medicine, were divided into two groups: one that underwent preoperative and postoperative periodical chest CT (periodical inspection group, PIG; May 2006 to January 2008, 135 patients) and one that did not undergo periodical chest CT (non-periodical inspection group, NPIG; September 2004 to April 2006, 131 patients) for comparison. Results The overall lung metastasis diagnosis rates did not manifest any significant difference. The times to diagnose lung metastasis patients were 6.3 months and 15.7 months for the PIG and the NPIG, respectively (P = 0.022). The size of the metastatic lung nodule was smaller in the PIG than in the NPIG (< 1 cm in 9/9 patients vs. < 1 cm in 6/9 patients in the PIG and the NPIG, respectively; P = 0.02). A solitary lung metastasis was more frequently found in the PIG (5/9 patients) than in the NPIG (1/11 patients) (P = 0.024). During the follow-up period, 100% (2/2 patients) and 60% (3/5 patients) of the patients in the PIG and the NPIG, respectively, with stage III cancer underwent a lung metastasectomy (P = 0.002). Conclusion Chest CT enables early diagnosis with a smaller size and a lower number of lung metastases in patients with colorectal cancer. Moreover, pulmonary the rate of the pulmonary resection for selected patients may be improved. However, the contribution of chest CT to increasing the survival rate must be investigated in a prospective randomized study.