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N Murase

Publications and source records attributed to N Murase.

266 records · Page 15Linked to original sources
PubMedDate not supplied

The future of transplantation: with particular reference to chimerism and xenotransplantation.

The assumption for the last third of a century that stem cell-driven hematolymphopoietic chimerism was irrelevant to successful conventional whole organ transplantation has prompted alternative inadequate explanations of organ allograft acceptance. This assumption clouded the biologic meaning of successful organ as well as bone marrow transplantation, and precluded the development of a cardinal principle that accommodated all facets of transplantation. Recognition of this error and the incorporation of the chimerism factor into a two-way paradigm have allowed previous enigmas of organ as well as bone marrow engraftment to be explained. No credible evidence has emerged to interdict this interactive concept. If the two-way paradigm is correct, it will allow the remarkable advances that have been made in basic immunology to be more meaningfully exploited for transplantation, including that of xenografts.

Animals↗
PubMedDate not supplied

Protective role of the L-arginine-nitric oxide synthase pathway on preservation injury after rat liver transplantation.

BACKGROUND: A major problem complicating liver transplantation is the preservation injury that results from cold storage and subsequent ischemia/reperfusion injury after organ revascularization. The L-arginine-nitric oxide (NO) pathway has been recognized to play critical roles during infection, inflammation, organ injury, and transplant rejection. Recent data indicates that NO synthesis has beneficial effects in several models of liver injury. The purpose of this study is to examine the role of the L-arginine-NO pathway on preservation injury in an experimental model of rat liver transplantation. METHODS: Orthotopic liver transplantation was performed in syngeneic (LEW to LEW) rats. Liver preservation injury was determined by measuring serum liver function tests 6 to 48 hours after transplantation. In some experiments, rats received L-arginine supplementation 0 to 24 hours after transplantation. In other experiments, NO synthase inhibitors (L-NAME or L-NIL) were injected at the time of isograft revascularization. RESULTS: L-Arginine supplementation decreased hepatic transaminase levels at all time points examined (6-48 hours). L-Arginine produced a significant improvement in liver preservation injury by 12 hours after reperfusion. The NO synthase inhibitor L-NAME caused a significant increase in liver injury 24 hours after injection. The inducible NO synthase (iNOS)-specific inhibitor L-NIL had no significant effect on liver injury. CONCLUSIONS: The results show that L-arginine supplementation and NO synthesis improve hepatic injury and have a protective role in the transplanted liver graft. The protective effect may be mediated by low-level cNOS-derived NO.

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PubMedDate not supplied

Interferon-gamma induced expression of MHC antigens facilitates identification of donor cells in chimeric transplant recipients.

After whole organ transplantation, donor bone marrow-derived cells migrate out of the graft into the recipient, leading to establishment of chimerism, which is the first step towards the subsequent induction of donor-specific tolerance. In routine immunohistochemical staining, monoclonal antibodies specific for heterotopic MHC alleles are used to identify donor and recipient cells. However, it is difficult to detect these cells using this technique in long-term allograft recipients who have a persistently low donor cell population (microchimerism). Because Interferon-gamma (IFN-gamma) is known to induce expression of MHC class I and class II cell surface molecules, we used this cytokine 12-48 h before sacrifice, to facilitate the identification of donor and recipient cells in the tissues of animals transplanted with either liver (B10-->C3H) or bone marrow (LEW-->BN). In long-term allograft recipients, the use of IFN-gamma for as briefly as 12 h prior to sacrifice, results in marked upregulation of class I and class II antigens, leading to easy identification of ubiquitously distributed low numbers of donor cells.

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PubMedDate not supplied

Indefinite survival of rat islet allografts following infusion of donor bone marrow without cytoablation.

We have tested the effect of donor bone marrow cell (DBMC) infusion on the survival of pancreatic islet allografts in the rat, without the use of cytoablative recipient conditioning. Lewis and diabetic Brown Norway rats were used as donors and recipients, respectively. Donor islets were placed beneath the left renal capsule. Infusion of DBMC and temporary immunosuppression followed by delayed islet transplantation resulted in indefinite survival of all islet grafts (MST > 180 days). Control animals demonstrated recurrent hyperglycemia (islet allografts rejection). Donor bone marrow derived cells were detected in the spleen and cervical lymph nodes of BN recipients of LEW bone marrow but not in the recipients of islet transplants alone. Second set full thickness skin grafts were performed in normal BN and in recipients of a previously successful ITX. Donor specific skin grafts were accepted in the animals that had received DBMC 40 days before the islet allograft, while animals receiving DBMC at the time of the islet allograft rejected the donor specific skin graft similarly to the controls. However, these animals did not reject a second set donor-specific islet transplant. The results indicate that radiation conditioning of the recipients was not necessary to induce microchimerism and graft acceptance in this rodent model of islet allotransplantation.

Animals↗
PubMedDate not supplied

Freeze-thawing behaviour of highly concentrated aqueous alkali chloride-glucose systems.

The freeze-thawing behaviour of highly concentrated aqueous alkali chloride-glucose systems was investigated by differential scanning calorimetry (DSC). In the aqueous NaCl-glucose solution system, single or double glass transitions followed by the corresponding devitrification exotherms were observed during rewarming. In the aqueous KCl-glucose solution system, on the other hand, a single glass transition followed by an exotherm was observed during rewarming. The presence of double glass transitions observed for a certain composition of the aqueous NaCl-glucose solution was taken as an evidence for the liquid-liquid immiscibility at low temperatures. Two kinds of crystallisation accompanied by exotherms during rewarming were identified by X-ray diffraction as ice and ice/NaCl x 2H(2)O, or ice/KCl eutectic component.

Calorimetry, Differential Scanning↗