Affinity of Endothelial Cells to a Polyurethane Vascular Graft: A Preliminary Animal Study

PURPOSE: Autologous vessels remain the gold standard for vascular grafts in microanastomoses. However, they are sometimes unavailable and have a limited long-term patency. Synthetic vessels have high success rates in large-diameter reconstructions but failed when used as small-diameter grafts due to graft occlusion. It has been proven that endothelial cell seeding improves prosthesis performance and long-term patency. Among polyurethane, PET and ePTFE, polyurethane has the best affinity to endothelial cells and mechanical properties closest to human vessels. We examined the ability of endothelial cells to attach to a polyurethane graft manufactured by the electrospinning method. METHODS: Endothelial cells, which were cultured from porcine internal jugular veins, were attached to polyurethane grafts with an internal diameter of 3mm. The same cells were attached to allogeneic decellularized porcine internal carotid artery grafts as controls. Both of the 10mm-long grafts were exposed to endothelial cells in a well for 1 hour. Each well contained 2x10(5) endothelial cells. The graft materials were rotated through 90 degrees every 15 minutes in order to minimize the effect of gravity. The extent of cell attachment was examined with the MTT assay. RESULTS: The MTT assay showed good incorporation of endothelial cells into both grafts. For the evaluation of affinity, the number of attached cells was counted at 10 fields of microscopic examination with x40 magnification. Endothelial cells adhered more to polyurethane grafts (mean, 127.4+/-6.2 cells) compared to porcine artery grafts (mean 45.8+/-5.1 cells)(p<0.05,Mann-Whitney test). CONCLUSION: In this study, we attached porcine endothelial cells to polyurethane grafts, manufactured by electrospinning. The grafts exhibited a better affinity to endothelial cells than allogeneic decellularized porcine internal carotid artery grafts. It is suggested that the time required for endothelial cells to attach to decellulized artery grafts may be longer than that which is required for attachment to polyurethane rafts.

The Comparison of High Frequency Jet Ventilation and/or Conventional Mechanical Ventilation in Dogs / 대한마취과학회지

BACKGROUND: High frequency jet ventilation (HFJV) which can be replaced conventional mechanical ventilation (CMV) is another method in respiratory care. But, each one has weakness. This study was designed to determine whether combined HFJV with CMV is more prominent than HFJV on cardiopulmonary system. METHOD: Korean mongrel dogs (n=11) were induced with thiopental sodium 10 mg/Kg, intravenously. Tracheal intubation was performed, and CMV (respiratory rate 30/min, VT 10 ml/Kg, FiO2 1.0) was applied. After placement of monitors, arterial blood pressure (BP), heart rate (HR), central venous pressure (CVP), cardiac output (CO), pulmonary capillary wedge pressure (PCWP) were measured for control values on steady state of vital signs. Thereafter, HFJV was done using respiratory rate 120/min, inspiratory time 30 %, driving pressure 40 psi for 60 min (examed at time of 15, 30, 60 min), and then CMV was supplemented to HFJV using VT 10 ml/Kg, respiratory rate 8, 4, 2, 1, 0.5/min for 150 min (examed at time of 30, 60, 90, 120, 150 min). All values were measured and analyzed on suggested times according to the different ventilatory modes. RESULT: Arterial BP, HR, CO, CVP and PCWP were not changed significantly during the 60 minutes of HFJV. PaCO2 was increased significantly from 33+/-9 mmHg to 45+/-12 mmHg (p<0.05) and arterial pH was decreased significantly from 7.39+/-0.10 to 7.29+/-0.11 (p<0.05) after 60 minutes of HFJV. PaO2 was not changed for HFJV. Variables (BP, HR, CO, CVP and PCWP) were not changed significantly after combined HFJV with CMV at each respiratiry rates. Elevated PaCO2 at the 60 minutes of HFJV was normalized after combined HFJV with CMV at respiratory rate of 8, 4, 2, 1, 0.5/min. (p<0.05) and decreased pHa was also normalized (p<0.05) after combined HFJV with CMV at respiratory rate of 8, 4, 2, 1/min. PaO2 was not changed for the time which we combind HFJV with CMV. CONCLUSION: The combinded HFJV with CMV makes expected arterial oxygenation and prevents accumulation of arterial carbon dioxide without depressive effect on cardiovascular system, when tidal volume of CMV is 10 ml/Kg and the respiratory rate is above 1/minute. So, this study suggests that the combined HFJV with CMV may be applied to respiratory failure effectively.

Prevalence of intestinal parasites in Korea

A survey of intestinal parasites infection among Korean people has been carried out during July 1969 to December 1970. A total of 2,250 stool specimens (male 1,101, female 1,146) was collected from all the provinces and Seoul city in Korea. The specimens were examined routinely by direct fecal smear, zinc sulfate flotation and formalin-ether sedimentation techniques. The results are summarized as follows: Of 2,250 specimens examined, l,803(80.l per cent) were positive for intestinal parasites. The positive rates of intestinal helminths were 1,644(73.1 per cent) among 2,250; Ascaris lumbricoides 46.0 per cent, Trichocephalus trichiurus 46.8 percent, hookworm 6.8 per cent, Trichostrongylus orientalis 7.0 percent, Clonorchis sinensis 12.1 percent, Enterobius vermicularis 1.6 per cent, Hymenolepis nana 0.7 percent, Taenia species 0.3 per cent, Metagonimus yokogawai 0.04 percent, Fasciolidae 0.04 per cent and one case of lung fluke Paragonimu westermani. The positive rstes of intestinal protozoa were 786(34.9 per cent); Entamoeba histolytica 6.4 per cent, Entamoeba coli 20.5 percent, Endolimax nana 10.0 per cent, Giardia lamblia 5.1 per cent, Trichomonas hominis 1.1 percent, Chilomastix mesnili 0.5 percent, Iodamoeba butschlii 0.6 percent, Enteromonas hominis 0.7 percent, Dientamoeba fragilis 0.1 per cent and one case of Isospora hominis. Sexual distribution of helminths and protozoan infections showed higher rate in female than that of male, except C. sinensis, H. nana, Taenia species or G. lamblia Infections of T. trichiurus, hookworm, T. orientalis, C. sinensis, Taenia species, E. histolytica, E. coli and E. nana increased with age. Conversely, H. nana and G. lamblia infections were more predominent in younger ages.