Biomedical subjects

Tetsu Sago

Publications and source records attributed to Tetsu Sago.

4 recordsLinked to original sources

PubMed2004

Translocation of Salmonella typhimurium in rats on total parenteral nutrition correlates with changes in intestinal morphology and mucus gel.

OBJECTIVE: We tested whether alterations in intestinal morphology and mucus gel correlate with differences in Salmonella typhimurium translocation between rats treated with total parenteral nutrition (TPN) and rats given a diet of chow. METHODS: Twenty-seven male Wistar rats were assigned to one of two groups: one received TPN for 14 d and the other (control) received standard rat chow and water ad libitum. Salmonella typhimurium (5 x 10(8) cells; GIFU 12142) was injected into a closed ileal loop. Portal venous blood (PVB), inferior vena cava blood (IVCB), and mesenteric lymph nodes (MLNs) were sampled for evaluation of bacterial translocation. Sections of the loop were prepared and stained with hematoxylin and eosin, periodic acid-Schiff (PAS), and fluorescein isothiocyanate-labeled Ulex europaeus agglutinin I (FITC-UEA-I) for image analysis. Perimeter, mucosal thickness, villus area, and positively stained mucus area were measured. A fluorescent antibody study was also done. RESULTS: Organisms were found in cultures of 1 in 13 control rats and 9 in 14 TPN rats. There were more bacteria in MLNs than in PVB or IVCB. There was no increase in the number of bacteria over time in PVB, IVCB, or MLNs. Perimeter and villus area (P < 0.001) and mucosal thickness (P < 0.01) were significantly smaller in the TPN group than in the control group. The positively stained mucus area was significantly smaller in the TPN group than in the control group (P < 0.05 with PAS, P < 0.01 with FITC-UEA-I). Salmonella typhimurium invaded specifically through Peyer's patches. In all culture-negative samples, bacteria were trapped by the mucous layer, with a very small number attached to the epithelial surface. CONCLUSION: Significant villous atrophy and reduction of mucus play an important role in the rapid translocation of S. typhimurium through Peyer's patches in rats after 2 wk of TPN.

Animals↗

PubMed2003

Graft-preserving treatment for vascular graft infected with Staphylococcus aureus with antibiotic-releasing porous apatite ceramic in the rabbit.

OBJECTIVE: This study was undertaken to investigate whether infection of a vascular graft with Staphylococcus aureus can be treated in situ by applying antibiotic-loaded porous apatite ceramic, in a rabbit model. METHODS: Teicoplanin (TEIC) was loaded onto a beta-tricalcium phosphate (TCP) block, a type of porous apatite ceramic. The activity of TEIC released from the antibiotic-loaded TCP block was examined in vivo. A vascular graft was patched onto the abdominal aorta in 24 rabbits, and S aureus was applied directly on it. Seven days postoperatively, each rabbit underwent repeat laparotomy, and retroperitoneal abscess around the prosthetic vascular patch was debrided. Animals were divided into four groups of 6 rabbits each. In group 1 only debridement was carried out. In groups 2 and 3, solution containing 40 or 60 mg of TEIC, respectively, was applied to the prosthetic vascular patch. In group 4, an antibiotic-loaded TCP block (63 +/- 6.6 mg of TEIC) was placed around the graft. Three weeks after the second operation, the graft, the tissue around it, and arterial blood were collected and cultured. RESULTS: TEIC activity was maintained for 28 days in vivo. In group 1, bacterial cultures of the prosthetic vascular graft and the tissue around it were positive in 5 animals and negative in 1 animal (infection rate, 83%). In both groups 2 and 3, cultures were positive in 3 animals and negative in 3 animals (infection rate, 50%). In group 4, cultures were negative in all animals (infection rate, 0%). Blood cultures were negative in all animals. Infection rate in group 4 was significantly lower than that in group 1 (P =.03), and was also lower than that in groups 2 and 3, but the difference was not significant. CONCLUSIONS: Use of slow-release antibiotic loaded onto a TCP block, along with debridement, may control infection in vascular grafts in situ, averting the necessity to remove the graft.

Administration, Topical↗

PubMed2003

Local treatment of Dacron patch graft contaminated with Staphylococcus aureus with antibiotic-releasing porous apatite ceramic: an experimental study in the rabbit.

OBJECTIVE: The purpose of this study was to investigate whether or not infection of prosthetic vascular graft could be prevented with the placement of antibiotic-loaded porous apatite ceramic on the graft with bacterial contamination. METHODS: Teicoplanin as an antibiotic was loaded into a beta-tricalcium phosphate (TCP) block of porous apatite ceramic. The activity of teicoplanin released from teicoplanin-loaded TCP was examined for 40 days at 2-day intervals. In an in vivo study, the graft was patched in the abdominal aorta of a rabbit. Two different doses of Staphylococcus aureus were applied (n = 13). Teicoplanin-loaded TCP was placed around the graft infected with S aureus (n = 6). The graft, the tissue around it, and the arterial blood were collected and cultivated 4 weeks after operation. RESULTS: The activity of teicoplanin in the replaced saline solution was maintained for at least 40 days. Because graft infection was established in all rabbits with a dose of 2 x 10(7) colony forming units, this dose was used as the dose of S aureus in this study. Fifty-seven percent of the subjects died from the infection. When teicoplanin-loaded TCP was placed around the graft contaminated with S aureus, no rabbits died. Bacterial cultures of the graft and of tissues around it were negative in all rabbits killed 4 weeks after operation. This infection was prevented with teicoplanin-loaded TCP in all rabbits. CONCLUSION: Teicoplanin-loaded TCP may be useful in avoiding Dacron graft infection with S aureus in rabbits.

Animals↗

PubMed2002

Dielectric spectrogram for evaluating ischemic microstructural changes of the liver in simple cold preservation.

PURPOSE: Monitoring ischemic liver injury is important in liver transplantation. We previously reported that dielectric properties were correlated with tissue adenosine triphosphate during liver preservation; however, it is unknown what the changes in dielectric properties are based on. Using rats, we studied the relationship between dielectric parameters and microstructural changes in liver tissues during preservation. METHODS: We serially measured the percent decrease in conductivity and the percent increase in relative permittivity in rat livers, and determined the areas of cellular and extracellular components using a charge-coupled device microscope and an NIH image. Thereafter, we evaluated the relationship between dielectric parameters and microstructural changes in the liver tissues. RESULTS: A positive linear and exponential correlation was found between the percent decrease in conductivity and the percent decrease in extracellular components ( P < 0.01). A positive linear and exponential correlation was also found between the percent increase in relative permittivity and the percent increase in cellular components ( P < 0.01). CONCLUSIONS: Our results suggest that the serial changes in tissue conductivity and the relative permittivity reflect changes in liver tissue microstructures during cold preservation.

Animals↗