Gelatin sealing sheet for arterial hemostasis and anti-adhesion in vascular surgery: a dog model study.

BACKGROUND: The bilayer gelatin sealing sheet was developed as a safe, effective, easy-to-handle and low-cost hemostatic agent. OBJECTIVE: To examine the feasibility of gelatin sealing sheets using a canine arterial hemorrhage model. METHODS: In vivo degradation of gelatin sealing sheets was examined by implanting subcutaneously in rats. For the hemostatic and anti-adhesion efficacy investigations, femoral arteries of dogs were pricked with syringe needle to make a small hole and a gelatin (i.e. experimental group) or fibrin glue sealing sheet (i.e. control group) was applied on the hole to stop bleeding (n=8). After discontinuation of the bleeding, the skin incisions were closed and re-examined 4 weeks postoperatively. RESULTS: From the degradation study, 4 h thermally treated gelatin sheet which degraded within 3 weeks in vivo was chosen for the further hemostatic study. In all cases of gelatin and fibrin glue sealing sheets, bleeding from the needle hole on canine femoral arteries was effectively stopped. Postoperative adhesions and inflammation at the site in the experimental group were significantly less than those in the control group (P<0.01 for adhesion scores). CONCLUSIONS: The gelatin sealing sheet was found to be as effective as the fibrin glue sealing sheet as a surgical hemostatic agent, and more effective in preventing postoperative adhesions.

The effect of mesenchymal stem cell osteoblastic differentiation on the mechanical properties of engineered bone-like tissue.

Mesenchymal stem cells (MSCs) can give rise to osteoblasts and have therefore been suggested as a cell source for bone engineering. Here we hypothesized that MSC osteoblastic differentiation and maturation can be supported by three-dimensional cultures in collagen hydrogels (hydrogel culture) to ultimately give rise to mechanically robust bone-like tissue. We first compared the osteoblastic differentiation efficiency of MSCs using osteoinductive supplements (ß-glycerophosphate, vitamin C, and dexamethasone) in a hydrogel culture and in a two-dimensional culture (2D culture) by assessing surrogate parameters for osteoblastic differentiation, including osteocalcin (OC) secretion and calcium (Ca) deposition. We next constructed ring-shaped bone-like tissues using MSCs in the hydrogel cultures, and assessed their mechanical (strain-strain analysis), biochemical/molecular (OC secretion, Ca deposition, and Runx2/osterix mRNA levels), and morphological (von Kossa staining) properties. OC secretions and Ca depositions were significantly higher in the hydrogel cultures than those in the 2D cultures, suggesting better osteoblastic differentiation and maturation in the hydrogel cultures. Collagen hydrogel-based ring-shaped bone-like tissues conditioned with osteoinductive supplements developed enhanced biomechanical properties, including high tissue stiffness and ultimate burst strength, superior molecular/biochemical properties, and morphological signs typically found in mineralized bone. These results may be exploited not only to generate bioartificial bone, but also to elucidate the basic mechanisms of bone physiology.

Effects of a simple intraoperative intrathoracic hyperthermotherapy for lung cancer with malignant pleural effusion or dissemination.

We examined the effect of a simple intraoperative intrathoracic hyperthermotherapy (IIH) and a simple intraoperative intrathoracic hyperthermo-chemotherapy (IIHC) on malignant pleural effusion and/or dissemination with primary non-small lung cancer. This study included 19 patients who had malignant pleural effusion and/or dissemination recognized for the first time at the time of surgery. We performed surgical procedures on the primary lesions and then the additional therapies followed. Seven patients received IIH (group A), five patients underwent IIHC (group B), and seven patients did not have any additional therapy (group C). There was no death during the follow-up period (9-35 months) in the group A. The median survival time was 41 months in the group B and 25 months in the group C. The group A was completely free of pleural effusion and one patient in the group B suffered from pleural effusion 26 months after surgery, although the median term of freedom from pleural effusion was three months in the group C. In patients with malignant pleural effusion and/or dissemination with primary non-small lung cancer, not only IIHC but also IIH might be beneficial in the prevention of pleural effusion instead of the improvement in prognosis.