A novel, ring-connected stent versus conventional GI stents: comparative study of physical properties and migration rates in a canine colon obstruction model.

BACKGROUND: Migration of stents is one of the most common adverse events in covered stent placement in GI tract obstruction. OBJECTIVE: To compare physical property and migration rates in a canine colon obstruction model among a novel stent and conventional stents. DESIGN: Comparative physical test and animal study. SETTING: Medical device testing laboratory and animal laboratory. SUBJECTS: Mongrel dogs (N=26). INTERVENTIONS: Surgical colon obstruction followed by placement of a novel (n=13) or conventional (n=13) stent. MAIN OUTCOME MEASUREMENTS: Physical properties, migration, and adverse events. RESULTS: The novel stent showed better flexibility, as in a physical test of longitudinal compressibility and axial force, than did conventional stents, and it withstood the fatigue test for 10 days. In terms of radial force and tensile strength, the novel stent showed the same or better results than conventional stents. In a canine colon obstruction model, the migration rate of a novel stent was significantly lower than that of a conventional stent (2/13, 15.4% vs 8/13, 61.5%; P=.008). LIMITATIONS: Animal study of limited size. CONCLUSION: The novel, ring-connected stent is more flexible and more resistant to migration than the conventional stents.

In vivo verification of regional hyperthermia in the liver.

PURPOSE: We performed invasive thermometry to verify the elevation of local temperature in the liver during hyperthermia. MATERIALS AND METHODS: Three 40-kg pigs were used for the experiments. Under general anesthesia with ultrasonography guidance, two glass fiber-optic sensors were placed in the liver, and one was placed in the peritoneal cavity in front of the liver. Another sensor was placed on the skin surface to assess superficial cooling. Six sessions of hyperthermia were delivered using the Celsius TCS electro-hyperthermia system. The energy delivered was increased from 240 kJ to 507 kJ during the 60-minute sessions. The inter-session cooling periods were at least 30 minutes. The temperature was recorded every 5 minutes by the four sensors during hyperthermia, and the increased temperatures recorded during the consecutive sessions were analyzed. RESULTS: As the animals were anesthetized, the baseline temperature at the start of each session decreased by 1.3℃ to 2.8℃ (median, 2.1℃). The mean increases in temperature measured by the intrahepatic sensors were 2.42℃ (95% confidence interval [CI], 1.70-3.13) and 2.67℃ (95% CI, 2.05-3.28) during the fifth and sixth sessions, respectively. The corresponding values for the intraperitoneal sensor were 2.10℃ (95% CI, 0.71-3.49) and 2.87℃ (1.13-4.43), respectively. Conversely, the skin temperature was not increased but rather decreased according to application of the cooling system. CONCLUSION: We observed mean 2.67℃ and 2.87℃ increases in temperature at the liver and peritoneal cavity, respectively, during hyperthermia. In vivo real-time thermometry is useful for directly measuring internal temperature during hyperthermia.

Therapeutic effects of human amniotic epithelial stem cells in Niemann-Pick type C1 mice.

BACKGROUND AIMS: Niemann-Pick disease type C1 (NPC) is an autosomal recessive cholesterol-storage disorder characterized by liver dysfunction, hepatosplenomegaly and progressive neurodegeneration. Thus far, studies of NPC mice have been performed mainly to study the brain and neurodegeneration, because degeneration in the brain was known as the primary cause of death in NPC mice. However, NPC is a systemic disease; therefore the purpose of this study was to find the possibility of a general therapeutic effect by applying and tracking transplanted human amniotic epithelial stem cells (hAESC) in NPC mice. METHODS: hAESC were administered to NPC homozygous (NPC(-/-)) mice via intravenous injection from 5 weeks of age; each recipient received 5 × 10(5) cells every other week. The body weight of each of the mice was measured every week, and the survival and state of each mouse was evaluated every day. The weight of the organs was measured, and serum chemistry, histology and the intensity of Filipin staining were evaluated. RESULTS: The effect of cell transplantation was to extend the life span and reduce the rapid loss of weight. Moreover, alleviation of tissue damage was observed more in hAESC-treated NPC(-/-) mice than in non-treated NPC(-/-) mice. Cholesterol deposition was reduced after transplantation, and the relative weight of the liver was also decreased. CONCLUSIONS: These data show that hAESC could delay the degeneration caused by fatal genetic disorders such as NPC. This study presents the prospect of relief of precipitous disease progression and the therapeutic possibility of applying hAESC to fatal genetic disorders.