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Biomedical subjects

K Fukunaga

Publications and source records attributed to K Fukunaga.

At least 343 records · Page 19Linked to original sources
PubMedDate not supplied

A simple, rapid, highly sensitive and reproducible quantification method for plasma malondialdehyde by high-performance liquid chromatography.

A simple, rapid, highly sensitive and reproducible quantification method for plasma malondialdehyde (MDA) was developed using high-performance liquid chromatography (HPLC). The present method is based on the thiobarbituric acid (TBA) reaction and reversed-phase HPLC separation with fluorescence detection. For sample preparation, an aliquot of 5 microL plasma was mixed with 0.2% (w/v) TBA in 0.1 M sodium acetate buffer, pH3.5. After heating at 95 degrees C for 60 min, the reaction solution was centrifuged and an aliquot of 10 microL supernatant was injected into the HPLC system without neutralization or extraction procedures. The TBA-MDA adduct was separated on a reversed-phase column and quantified by a fluorescence detection (lambda ex = 515 nm; lambda em = 553 nm). The mobile phase was a mixture of acetonitrile: water (7:3, v/v) under isocratic conditions at ambient temperature. These procedures gave good results with regard to sensitivity (detection limit S/N = 3, 0.5 fmol per injection), linearity (0.5-500 fmol per injection), precision (between-assay C.V = 3.1%, within-assay C.V = 1.2%) and recovery (98.6%). The simple sample procedure, the highly sensitive detection limit and the stability of the TBA-MDA adduct make the present method applicable to numerous clinical samples. As many as 250-300 samples per day can be assayed using an autosampler.

Adult↗
PubMedDate not supplied

Backtransplantation for survival of the graft.

To assess survival of grafts after uncontrollable rejection, one performs backtransplantation from the recipient to the donor. This study investigated backtransplantation in an animal model. Hearts were transplanted heterotopically in rats. After a few days, the transplanted heart grafts were harvested from the recipients and backtransplanted to the donor strain heterotopically and a drug was administered. Cardiac grafts survived 6.2 days in the first recipients. After backtransplantation on day 5 or 6, all backtransplanted grafts survived well in the second recipients. After backtransplantation on day 7, when 4 of 5 grafts had no beat, 2 of 5 grafts recovered beating on day 3 after backtransplantation without any drug treatment. After backtransplantation on day 7, when 4 of 5 grafts had no beat, all (5 of 5 grafts) recovered beating well with the administration of FTY720 on day 3 after backtransplantation. CsA or FK506 had no effect on survival after backtransplantation. Pathological findings revealed mild cellular infiltration in the cases of FTY720 and severe necrosis in the cases of no drug, CsA, or FK506. After backtransplantation on day 8, no grafts (0 of 5 grafts in each drug) recovered beating with any drugs. These data document the possibility of backtransplantation.

Animals↗
PubMedDate not supplied

Activation of intracellular neutrophil elastase in the transplantation of ischemic liver.

Ischemia-reperfusion injury is an important cause of primary nonfunction of transplanted organs, and neutrophil elastase has been implicated in the pathophysiology of ischemia-reperfusion injury. We assessed the kinetics of intracellular neutrophil elastase (INE) activity in canine liver transplantation. Mongrel dogs underwent orthotopic whole-liver transplantation. The animals in group I (n = 6) received fresh liver grafts, and all of the dogs survived longer than 24 h. The animals in group II (n = 5) received liver grafts injured by 30 min of warm ischemia. Only 1 animal survived longer than 24 h after reperfusion. A significant increase in the serum ALT and LDH levels was observed in group II after reperfusion of the graft. Isolated peripheral neutrophils were homogenized, and the neutrophil elastase activity in the supernatant was determined by using a spectrophotometric assay. The INE activity was expressed as the neutrophil elastase value per 1 x 10(10) peripheral neutrophils. In group I, the INE activity 10 min and 2 h after reperfusion was 7.6 +/- 2.6 and 6.1 +/- 2.4 U, respectively. In group II, this activity was 25.9 +/- 7.4 and 44.3 +/- 23.7 U, respectively. There was a significant correlation between serum LDH levels and INE activity 10 min after reperfusion (gamma = 0.70, p < 0.02). In conclusion, the INE activity increased more sharply after the reperfusion of ischemically injured liver grafts. The INE activity correlates with serum LDH levels immediately after reperfusion, suggesting that the increase in the INE activity depends on the severity of ischemic damage.

Alanine Transaminase↗
PubMedDate not supplied

Clonogenic colony-forming ability of flow cytometrically isolated hepatic progenitor cells in the murine fetal liver.

Stem cells are defined as cells having multilineage differentiation potential and self-renewal capability. Hepatic stem cells have aroused considerable interest not only because of their developmental importance but also for their therapeutic potential. However, their presence in the liver has not yet been demonstrated. With the use of a fluorescence-activated cell sorter (FACS) and monoclonal antibodies, we attempted to ascertain whether hepatic stem cells are present in the murine fetal liver. For this purpose, we optimized a cell isolation technique for FACS sorting of fetal liver cells. When isolated CD45 TER119 cells (the non-blood cell fraction in the fetal liver) were tested for their clonogenic colony-forming ability, mechanical dissociation (pipetting) was the most suitable cell isolation technique for FACS sorting. We confirmed that these colonies contained not only cells expressing hepatocyte markers but also cells expressing cholangiocyte markers. To identify hepatic stem cells, studies must focus on CD45TER119- cells in the murine fetal liver.

Animals↗