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Hyperacute rejection (HAR) mediated by the natural antibody (nAb) against Gal alpha 1-3Gal beta-4-GlcNAc (alpha Gal) is the major obstacle in xenogeneic organ transplantation. Previously, we reported the acceptance of donor heart grafts in anti-alpha Gal nAb-producing galactosyltransferase knockout (GalT KO) mice after cyclophosphamide (CP)-induced tolerance conditioning. In the present study, we applied our tolerance induction conditioning in presensitized recipient mice.GalT KO (alpha Gal(-/-), H-2(b/d)) recipient mice were presensitized with alpha Gal(+) rabbit red blood cells (RRBCs). Presensitized or nonsensitized recipient mice were treated with CP-induced tolerance conditioning, consisting of AKR (alpha Gal(+/+), H-2(k)) spleen cells (SC), CP, busulfan (BU), and AKR bone marrow cells (BMC). We assessed the survival of donor hearts and skin grafts and analyzed the production of anti-alpha Gal Abs by flow cytometry.Donor mixed chimerism was achieved in the presensitized GalT KO mice treated with CP-induced tolerance conditioning. In parallel with the disappearance of anti-alpha Gal Abs, permanent acceptance of donor heart grafts and skin grafts was observed in presensitized and GalT KO mice treated with CP-induced tolerance conditioning.Both B-cell and T-cell tolerance was achieved in the presence of a higher titer of anti-alpha Gal Abs after treatment with CP-induced tolerance conditioning.

Background. Recent studies have indicated that natural killer T (NKT) cells are essential for the establishment of transplantation tolerance. In the present study, we have elucidated the role of recipient and donor NKT cells in cyclophosphamide (CP)-induced tolerance. Method. DBA/2 (DBA; H-2 d ) mice were used as donors and BALB/c (BALB; H-2 d ) wild-type (WT) or Vaα14 NKT-knockout (KO, BALB/c background) mice were used as recipients. Recipients were treated with CP-induced tolerance regimen, which consists of donor spleen cells (SC) on day 0 and CP on day 2. In some experiments, NKT KO mice, which received NKT cells from either WT, inferon- y KO, or interleukin-4 KO mice, were treated with tolerant regimen. To deplete Ly49 inhibitory receptors on NKT cells in the recipient mice, anti-Ly49 monoclonal antibody cocktails were injected on day - 1 when indicated. Results. Donor skin graft was permanently accepted in recipient BALB WT mice with induction of donor mixed chimerism. On the contrary, donor DBA skin allografts were chronically rejected in NKT KO recipient. Lower levels of mixed chimerism were observed in NKT KO recipients comparing to the WT recipients. The production of interferon-γ or interleukin-4 from NKT cells did not affect the induction of tolerance. Depletion of Ly49 positive NKT cells abrogated the induction of skin graft tolerance. Conclusion. Recipient NKT cells, but not donor NKT cells, were dominantly required for the induction of allograft tolerance. Our results indicated that the single cytokine produced by NKT cells did not mediate the regulatory function in the induction of allograft tolerance.

We previously developed a cyclophosphamide (CP)-induced tolerance protocol, consisting of an intravenous injection of 1 x 10(8) donor spleen cells (SC) given on day 0 and an intraperitoneal injection of 200 mg/kg CP given on day 2. In the present study, we modified this protocol with natural killer cell (NK) depletion in recipient mice, and evaluated the efficacy of tolerance induction.We used B10.D2 (H-2d; IE+) and B10 (H-2b; IE-) mice as both donors and recipients. The recipient mice were treated with donor SC, CP, and donor bone marrow cells (BMCs) with or without NK depletion.A higher level of mixed chimerism was achieved in the NK-depleted recipients. Survival of both the skin and heart donor grafts was significantly prolonged in the NK-depleted recipients. Donor reactive Vbeta11+ T cells were found at the same level as in untreated control mice. Pretreatment with recipient NK cell depletion was effective in inducing higher levels of donor mixed chimerism; however, permanent engraftment of donor bone marrow was not achieved.Survival of donor grafts was remarkably prolonged in the NK cell-depleted group, but transplantation tolerance could not be induced. Our results suggest that NK cell depletion in CP-induced tolerance conditioning has some effect on the induction of donor-specific tolerance.

The current critical shortage of human donor organs has stimulated the feasibility of the xenogenic transplantation, such as swine to primate. We have previously reported the induction of donor-specific tolerance in MHC-disparated recipient mice by using our cyclophosphamide (CP)-induced tolerance conditioning. In this study, we examined the efficacy of our CP-induced tolerance conditioning in xenogenic transplantation model. F344 rats and B10 mice were used as donors and recipients. Recipient mice were treated with donor spleen cells, CP, Busulfan and bone marrow cells, with or without prior NK-cell depletion. Donor mixed chimerism, and the presence of donor reactive T-cell population were analysed by flow cytometry. The survival of the donor skin grafts were observed after the conditioning. Donor mixed chimerism was temporary induced but terminated at 10 weeks after treatments. Donor-specific prolongation of the skin graft survival was observed after the treatments, however, grafts were rejected in the long term. NK-cell depletion, prior to the treatments, did not affect the levels of the mixed chimerism or graft prolongation. The donor-reactive recipient T-cell population was remained the same level as the untreated mice, suggesting the failure of the induction of the central T-cell tolerance. Thus, partial efficacy of our CP-induced tolerance treatments in the rat to mice xenotransplantation was observed. Our results suggested that the additional treatments were required to establish the stable xenogenic tolerance.

Recently, much attention has been paid to nonmyeloablative allogeneic stem cell transplantation for the treatment of metastatic renal cancer. Mature donor T cells cause graft-versus-host disease (GVHD) although they are also the main mediators of the beneficial graft-versus-tumor activity associated with this treatment. Hence, the segregation of the graft-versus-tumor activity from GVHD is an important challenge in managing the clinical course of treatment. We previously reported a series of studies regarding the allograft tolerance induced by allogeneic spleen cells (with bone marrow cells) and cyclophosphamide in mice. Here, we show a modified cyclophosphamide-induced tolerance system for the treatment of murine renal cell carcinoma, RENCA, by shifting the equal balance between graft-versus-host and host-versus-graft reactions toward graft-versus-host reaction with donor lymphocyte infusion. Our results clearly show the antitumor activity against RENCA with only low levels of mixed chimerism in the periphery and the in vivo and in vitro acquired immunity against RENCA even when mixed chimerism is almost undetectable. Because the withdrawal of mixed chimerism reduces the risk of GVHD, the antitumor activity is thus sequentially segregated from the initial GVHD in our model. We believe that this is the first unique model system of nonmyeloablative allogeneic hemopoietic cell transplantation to ever be reported for the treatment of renal cancer.

In the present study, we have elucidated the efficacy of two cyclophosphamide (CP)-induced tolerance protocols for the induction of B-cell tolerance against Galalpha1-3Galbeta1-4GlcNAc (alphaGal) antigens. alpha1,3-galactosyltransferase-deficient (GalT-/-; H-2(b/d)) mice received with 1 x 10(8) AKR (alphaGal+/+ H-2k) spleen cells (SC) followed by 200 mg/kg CP, or alternatively followed by 200 mg/kg CP, 30 mg/kg Busulfan (BU) and 1 x 10(8) T-cell-depleted AKR bone marrow cells (BMC). The generation of both anti-alphaGal and anti-donor antibodies were completely suppressed, but normal antibody production against third party antigens was observed after BALB/c skin grafting in both groups of GalT-/- mice. In GalT-/- mice, treated with SC and CP, mixed chimerism was not observed. Cellular rejection was observed in grafted donor AKR hearts with an absence of humoral rejection, whereas humoral rejection was observed in untreated GalT-/- mice. On the other hand, long-term mixed chimerism and permanent acceptance of donor AKR skin graft and heart graft were achieved in GalT-/- mice treated with SC, CP, BU and BMC. These results demonstrate the efficacy of classical drug-induced tolerance in the induction of B-cell tolerance against alphaGal antigens. However, induction of stable mixed chimerism was required for the suppression of cellular rejection.

We recently described using cyclophosphamide (CP) plus busulfan (BU) to create drug-induced skin and heart allograft tolerance capable of regularly overcoming fully H-2 mismatched barriers in mice. The present study investigates the intragraft mRNA expressions of Th1 and Th2 cytokines.This method consists of the intravenous (i.v.) injection of 1 x 10(8) allogeneic spleen cells on day 0, the intraperitoneal injection of 200 mg/kg CP and 30 mg/kg BU on day 2, and the i.v. injection of 1 x 10(7) T cell-depleted allogeneic bone marrow cells from the same strain of mice on day 3. Heart grafting (HG) was performed on day 28. Chimerism in the peripheral blood was monitored by flow cytometric (FCM) analysis. The frequency of certain V(beta) families was determined by FCM to assess deletion of donor-reactive T cells. Th1 (interleukin [IL]-2, interferon [IFN]-gamma) and Th2 (IL-4, IL-10) cytokine expression in the heart grafts was analyzed with reverse transcription-polymerase chain reaction.In a fully MHC mismatched combination of B10.D2 (H-2d, IE+) --B10 (H-2b, IE-), B10.D2 heart grafts were accepted permanently in a donor-specific manner, mixed chimerism was observed, and IE-reactive V(beta)11+ T cells were specifically reduced in the periphery from the recipient B10 mice. In the donor B10.D2 heart grafts, there was no accumulation of Th1 (IL-2, IFN-gamma) or Th2 (IL-4, IL-10) cytokines.These results show that the drug-induced tolerance we established can regularly induce long-lasting heart allograft tolerance without intragraft mRNA accumulation of Th1 or Th2.

By using a cyclophosphamide (CP)-induced tolerance system, we previously raised the possibility that the degree of chimerism might determine the induction of heart and skin allograft tolerance. When C3H (H-2k; Thy1.2, Mls-1b) mice were intravenously primed with 1 x 10(8) spleen cells (SCs) from H-2 matched AKR (H-2k; Thy1.1, Mls-1a) mice and then treated intraperitoneally with 200 mg/kg CP, the survival of AKR skin grafts was permanently prolonged in a tolerogen-specific fashion. After this treatment, a minimal degree of mixed chimerism and the clonal destruction of Mls-1a-reactive CD4+Vbeta6+ T cells in the periphery were observed. When AKR SCs and 100 mg/kg CP were used for conditioning, the survival of the AKR skin grafts was mildly prolonged. The clonal destruction of CD4+Vbeta6+ T cells in the periphery was induced and a minimal degree of mixed chimerism was detectable. The degree of mixed chimerism induced with AKR SCs and 200 mg/kg CP was significantly higher than that with AKR SCs and 100 mg/kg CP during the observation. On the other hand, neither skin allograft prolongation nor permanent mixed chimerism could be induced when C3H mice were treated with AKR SCs and 50 mg/kg CP. In order to increase the degree of mixed chimerism, we injected 1 x 10(8) tolerant AKR SCs on day 3 into the recipient C3H mice that had been treated with AKR SCs on day 0 and with 100 mg/kg CP on day 2. The reason that we used tolerant SCs was that untreated AKR SCs caused graft-versus-host disease in most of the recipients. Tolerant AKR SCs were harvested from AKR mice that had been treated with C3H SCs and 200 mg/kg CP 2 weeks earlier, and did not contain regulatory cells. By adoptive transfer, the degree of chimerism was stably and significantly increased in all recipients, and AKR skin graft tolerance was induced in half of the recipients. T-cell-depleted bone marrow cells (BMCs) from untreated AKR mice induced skin allograft tolerance in 83% of recipients. Thus, the present study strongly confirmed the hypothesis that a higher degree of chimerism is required for the induction of skin allograft tolerance in CP-induced tolerance.

1997年の臓器移植法施行後,当科で機械的流量補助を必要とした6名において,重症心不全に対する初期の治療戦略を検討した.症例は急性心筋梗塞2例,拡張型心筋症3例,劇症型心筋炎1例.補助手段は,経皮的心肺補助(PCPS)2例,補助人工心臓(VAD)4例であり,うち2例は急激な循環不全のためPCPSを使用した.1)急性循環不全によりPCPSを導入した2例中1例離脱,1例はPCPS施行中に多臓器不全(MOF)で死亡した.2)慢性心不全の急性増悪によりVADを導入した2例は経過良好であったが,頻回の塞栓症を併発し,1例はMOF,他の1例は脳梗塞で死亡した.3)VAD導入前にPCPSを用いた2例は,VAD導入前の総ビリルビン値(T.Bil)が14.9,20.9mg/dlであり,最終的にMOFで死亡した.重症心不全の治療では,PCPSは急性循環不全症例に効果があるが,1)心機能の回復が認められない場合,2)経過中T.Bilが上昇する場合,早急にVADへの変更を考慮すべきである.

繊維含有量44vol%の三次元炭素繊維強化フラン樹脂 (3D-CFRFR) を作製し, 1000℃以下の種々の温度で加熱した. 1000℃の加熱による体積収縮は, フラン樹脂単体で50%であったが, 3D-CFRFRでは数%であった. 曲げ強さは加熱処理温度 (HTT) の上昇に伴って減少した. フラン樹脂に対する繊維強化効果はHTT500℃以下で認められた. 加熱に伴う曲げ強さの低下は, マトリックスと炭素繊維境界面のはく離と炭素繊維の損傷による. はく離や損傷はマトリックスのフラン樹脂の熱分解を通して起こる. 炭素繊維積層表面直角方向 (σs, Es) の曲げ強さと曲げ弾性率は, 厚さ直角方向 (σt, Et) のそれらより小さかった. 両方向の曲げ強さおよび両方向の曲げ弾性率には直線関係があり, それぞれσt=2.7σs, Et=1.7Esで表される.

Aortic valve surgery carries increased risks in patients with an extensively calcified aorta. We describe a technique in which we maintain systemic perfusion via bilateral axillary artery perfusion in conjunction with endoaortic balloon occlusion, and limit the circulatory arrest time. (J Card Surg 2012;27:689-691)

Background. Recently, we have described a drug (cyclophosphamide [CP] plus busulfan [BU])-induced skin allograft tolerance in mice that can regularly overcome fully H-2-mismatched barriers. Using this method, we have investigated whether or not this regimen can prolong the survival of heart allograf

Background The presence of bilateral superior venae cavae may add complexity to the performance of a bidirectional Glenn procedure (BDG). Stagnation of blood flow between the two cavopulmonary anastomoses may increase the risk of thrombosis and impair central pulmonary artery growth. Methods Forty patients underwent BDG from January 2004 to April 2011. The cohort was divided into two groups: those receiving bilateral BDG (b-BDG, n = 13) and those receiving unilateral BDG (u-BDG, n = 27). Operative, angiographic, and follow-up data were analyzed retrospectively. Results None of the patients experienced thrombosis. There was no difference in actuarial survival rate (u-BDG vs b-BDG, 100% vs 92% at 5 years, p = 0.15). On follow-up angiography, no difference in central pulmonary artery index was noted (78.4 ± 45.5 vs 60.4 ± 32.1, p = 0.24). Central pulmonary artery stenosis was detected in 6 patients (4 with u-BDG and 2 with b-BDG), 4 of whom (2 from each group) underwent balloon pulmonary artery plasty before the Fontan procedure. There was no difference in freedom from reintervention for central pulmonary artery stenosis (93% vs 85% at 1 year, p = 0.59). The rate of Fontan completion was comparable between groups, with similar operative variables and satisfactory outcomes. Conclusions Bilateral BDG did not increase the risks of thrombosis and central pulmonary artery hypoplasia and can be performed safely without altering the outcome of the Fontan procedure.

A pure method of drug (cyclophosphamide plus busulfan)-induced skin allograft tolerance in mice that can regularly overcome fully H-2-mismatched barriers in mice has been established. The components of the method are i.v. administration of 1 × 108 allogeneic spleen cells on day 0, i.p. injection of 200 mg/kg CP and 25 mg/kg busulfan on day 2, and i.v. injection of T cell-depleted 1 × 107 bone marrow cells from the same donor on day 3. Recipient B10 (H-2b; IE−) mice prepared with this conditioning developed donor-specific tolerance, and long-lasting survival of skin allografts was shown in almost of the recipient mice. In the tolerant B10 mice prepared with new conditioning, stable multilineage mixed chimerism was observed permanently, and IE-reactive Vβ11+ T cells were reduced in periphery as seen in untreated B10.D2 (H-2d; IE+) mice. The specific tolerant state was confirmed by the specific abrogation against donor Ag in the assays of CTL activity and MLR and donor-specific acceptance in the second skin grafting. These results demonstrated that the limitation of standard protocol of cyclophosphamide-induced tolerance, which have been reported by us since 1984, can be overcome by the additional treatments with the myelosuppressive drug busulfan, followed by 1 × 107 T cell-depleted bone marrow cells. To our knowledge, this is the first report to induce allograft tolerance with a short course of the Ag plus immunosuppressive drug treatment without any kind of mAbs (pure drug-induced tolerance).

A number of researches have been made for the (Euclidean) Taub-NUT metric, because the geodesic for this metric describes approximately the motion of well separated monopole-monopole interaction. From the viewpoint of dynamical systems, it is well known also that the Taub-NUT metric admits the Kepler-type symmetry, and hence provides a nontrivial generalization of the Kepler problem. More specifically speaking, because of a U(1) symmetry, the geodesic flow system as a Hamiltonian system for the Taub-NUT metric is reduced to a Hamiltonian system which admits a conserved Runge-Lenz-like vector in addition to the angular momentum vector, and thereby whose trajectories turn out to be conic sections. In particular, all the bounded trajectories of the reduced system are closed. The Taub-NUT metrics is generalized so that the reduced system may remain to have the property that all of bounded trajectories are closed. On the application of Bertrand's method to the reduced system, two types of systems are found: one is called the Kepler-type system and the other the harmonic oscillator-type system. Correspondingly, two types of metrics come out: the Kepler-type metric and the harmonic oscillator-type metric. Furthermore, the symmetry of the Kepler-type system and of the harmonic oscillator-type system are studied through forming accidental first integrals. Thus the generalization of the Taub-NUT metric accomplishes nontrivial generalizations of the Kepler problem and the harmonic oscillator.

Recently, we experienced three atypical arch replacement cases. In these cases, we performed reconstruction of four arch vessels (because of anomaly of arch vessels). In such cases, it takes longer time for reconstruction of arch vessels. We used arch first technique with combined retro and partial-ante cerebral perfusion. Mean circulatory arrest time (including retrograde cerebral perfusion) was 44.3 ± 4.1(min),and Partial antegrade cerebral perfusion time was 21.5 ± 2.1 min. Postoperative courses were good. And there were no cerebral complication. Arch first technique with combined cerebral perfusion was thought to be safe and effective (for good operative field) method for atypical arch replacement.

Aortic injury occurred during resternotomy in a 22-year-old woman who had undergone a Rastelli-type operation. Although extracorporeal circulation using the right femoral artery and vein was commenced immediately, hemostasis through the midline incision was impossible, and her circulation was hardly maintained. Thus, the parasternal approach was attempted, dividing the right first through fourth ribs and the head of the right clavicle. This approach enabled the assistant to give effective compression to the aortic injury site. Dissection of the adhesions around the ascending aorta was safely carried out, and the aortic laceration was closed without the help of circulatory arrest.

A 73-year-old woman was referred to our hospital to investigate dilatation of an aortic arch which had been detected by a chest roentgenogram and severe aortic valve regurgitation detected by echocardiography. On admission, a computed tomography scan of the chest showed a large fusiform ascending aortic aneurysm. She had not shown any symptoms such as headache or polymyalgia rheumatica and had no significant coronary atherosclerosis. She underwent aneurysmectomy and reconstruction of the ascending aorta using cardiopulmonary bypass without aortic valve replacement, and pathological examination of the aneurismal wall revealed giant cell arteritis (GCA). Preoperatively, she did not have any temporal pain, and no signs of inflammation were detected serologically. Postoperatively, aortic valve regurgitation improved and she did well. However, three months after the surgery, she died suddenly due to the rupture or dissection of aorta. In the Japanese population, GCA is reportedly a rare cause of aortic aneurysm. However, retrospective studies show that GCA affects the aorta and that thoracic aortic aneurysm is a possible complication of GCA. In cases of the thoracic aortic aneurysms with unknown etiology, there is a possibility that GCA is the cause of the aortic aneurysm.

Background. Natural killer T (NKT) cells play crucial roles in preventing autoimmune diseases and inducing transplantation tolerance. We investigated whether cyclosporin A (CsA), which is generally used in clinical transplantation and autoimmune disease therapy, could modulate the NKT cell activation induced by α-galactosylceramide (a-GalCer) treatment. Methods. C57BL/6 (B6) mice were given daily intraperitoneal injections of CsA (30 or 50 mg/kg) from day - 1 and injected intravenously with α-GalCer (2 μg/mouse) on day 0. The kinetics of NK1.1 + CD3 + or NK1.1 + Thy1.2 + cells in the liver and spleen were analyzed by flow cytometry. Apoptosis of NK1.1 + CD3 + cells, cytokine levels (interleukin [IL]-2, IL-4, IL-10 and interferon [IFN] -y) in the recipient serum and changes in dendritic cell activation in the spleen were analyzed. Results. In B6 mice treated with α-GalCer, NK1.1 + CD3 + cells rapidly decreased in both the liver and spleen, and repopulated to their normal levels by day four, while NK1.1 + Thy1.2 + cells rapidly decreased, expanded by day four and reduced to their normal level by day 15. When B6 mice were treated with α-GalCer plus 30 or 50 mg/kg CsA, NK1.1 + CD3 + or NK1.1 + Thy1.2 + cells were similarly decreased and then expanded via extensive proliferation by day seven or four, respectively. When B6 mice were treated with α-GalCer, substantial amounts of IL-2, IL-4 and IFN-y were produced, and the surface markers of dendritic cells were upregulated. However, these cytokine productions and maturation of dendritic cells were profoundly suppressed after treatment with α-GalCer and CsA. Apoptosis of NK1.1 + CD3 + cells was not affected in mice treated with α-GalCer or α-GalCer and CsA. Conclusions. CsA suppresses α-GalCer-induced cytokine productions and dendritic cell maturation of mouse NKT cells but does not decrease NK1.1 + CD3 + cells on day one. The modulation of NKT-mediated immunoregulatory functions by CsA requires careful consideration in clinical transplantation and autoimmune disease therapy.

We have previously reported the sequential mechanisms of cyclophosphamide (CP)-induced tolerance. Permanent acceptance of donor skin graft is readily induced in the MHC-matched and minor Ag-mismatched recipients after treatment with donor spleen cells and CP. In the present study, we have elucidated the roles of NKT cells in CP-induced skin allograft tolerance. BALB/c AnNCrj (H-2d, Lyt-1.2, and Mls-1b) wild-type (WT) mice or Vα14 NKT knockout (KO) (BALB/c) mice were used as recipients, and DBA/2 NCrj (H-2d, Lyt-1.1, and Mls-1a) mice were used as donors. Recipient mice were primed with 1 × 108 donor SC i.v. on day 0, followed by 200 mg/kg CP i.p. on day 2. Donor mixed chimerism and permanent acceptance of donor skin allografts were observed in the WT recipients. However, donor skin allografts were rejected in NKT KO recipient mice. In addition, the donor reactive Vβ6+ T cells were observed in the thymus of a NKT KO recipient. Reconstruction of NKT cells from WT mice restored the acceptance of donor skin allografts. In addition, donor grafts were partially accepted in the thymectomized NKT KO recipient mice. Furthermore, the tolerogen-specific suppressor cell was observed in thymectomized NKT KO recipient mice, suggesting the generation of regulatory T cells in the absence of NTK cells. Our results suggest that NKT cells are essential for CP-induced tolerance and may have a role in the establishment of mixed chimerism, resulting in clonal deletion of donor-reactive T cells in the recipient thymus.

Previously, we have shown that cyclophosphamide (CP)-induced tolerance, marked by permanent acceptance of donor skin graft and establishment of donor mixed chimerism, was readily induced with treatment with donor spleen cells (SC), CP, busulfan (BU) and donor bone marrow cells (BMC). Here, we investigated the mechanism of anti-donor natural antibody (nAb) producing B-cell tolerance in our CP-induced tolerance systems in alpha1,3-galactosyltransferase-deficient knockout mice (GalT KO; GalT-/-, H-2(b/d)). After induction of tolerance using donor AKR SC and BMC, survival of donor heart and skin grafts and production of anti-Galalpha1-3Galbeta1-4GlcNAc (anti-alphaGal) Ab in recipient GalT KO mice were analyzed. In addition, the production of anti-alphaGal Ab and the presence of Gal-BSA binding B cells in GalT KO mice were analyzed by flow cytometry (FCM) after treatments with rabbit red blood cells (RRBC) and CP. Permanent acceptance of donor skin and heart grafts and abrogation of anti-alphaGal Ab were achieved in GalT KO mice treated with donor SC + CP/BU + BMC. However, in the GalT KO mice treated with donor SC and CP, donor skin grafts were acutely rejected, even though anti-alphaGal Ab was undetectable. Similarly, anti-alphaGal Ab was undetectable in GalT KO mice treated with RRBC and CP. Our data strongly indicated the following mechanisms: the clonal destruction in the early stage and the clonal anergy or ignorance in the late stage after conventional conditioning with RRBC and CP. In conclusion, our drug-induced tolerance protocols are effective to induce tolerance in recipients that produce anti-donor nAb.

Ly-49A is an inhibitory receptor that binds H-2Dd and H-2Dk. The downregulation of Ly-49A is thought to mediate NK self tolerance in vivo. In this study, we analyzed the regulation of Ly-49A, D and G2 on NK cells in an in vivo rejection model. After injection with 1 x 10(8) B10.D2 spleen cells (SC) into B 10 mice, we found Ly-49A downregulated within 3 h on NK cells of B10 mice, whereas expressions of Ly-49D and G2 were augmented. To investigate effects of different expression patterns of Ly-49 receptors on NK cells, Ly-49A, D or G2-depleted B10 mice were inoculated with B10.D2 SC. NK cells from SC of Ly-49A-depleted and B10.D2 SC-injected B10 mice showed enhanced cytotoxicity to Dd-positive targets in vitro. Furthermore, reduced numbers of B10.D2 SC were observed in Ly-49A or G2-depleted B10 mice, whereas increased numbers of B10.D2 SC were observed in Ly-49D-depleted B10 mice after inoculation with B10.D2 SC in vivo. These findings indicated that the downregulation of Ly-49A and the augmentation of Ly-49D expression may mediate NK cells to recognize and kill Dd antigen efficiently. In conclusion, each Ly-49 isoform may play independent roles in the regulation of activation or inhibition on NK cells.

There are an increasing number of reports concerning mitral valve repair by a reconstruction of the chordae tendinae using expanded polytetrafluoro-ethylene (PTFE) sutures. However, little information is available about extended application or results of this technique for an extended prolapse of the anterior mitral leaflets.Between July 1991 and August 2003, 28 patients with moderate to severe mitral regurgitation as a result of a prolapse of anterior leaflets (age range, 15-73 years) underwent mitral valve repair by reconstruction of the artificial chordae with 4-CV expanded polytetrafluoroethylene sutures without a leaflet resection. Either Kay's suture technique or ring annuloplasty was also performed to correct annular dilatation in all patients.No operative death or late mortality was observed. The prolapsed segment, which was successfully repaired, was within 33% of the anterior mitral leaflet (AML) in 6 patients, from 33% to 50% in 5, from 50% to 99% in 11, and 100% in 6 patients. Before discharge, immediate postoperative echocardiography showed less than moderate mitral regurgitation in 28 of 28 patients. The follow-up, consisting of a clinical examination and serial echocardiograms, was complete in all cases and the mean follow-up period was 80.6 months (range, 12-146). There were two failures that required a reoperation because of a worsening mitral regurgitation and hemolytic anemia (elongation of anchored side of papillary muscle). The other two patients required mitral valve replacement due to a progressive regression of the left ventricular function, although the regurgitation worsened from a mild level to a moderate one. When the reoperated patients were excluded from the following data, the degree of mitral regurgitation, estimated by echocardiography performed at recent follow-up period, was none in 10 patients, trivial in 13 patients, and mild in 1 patient. In addition, the systolic and diastolic dimensions of the left ventricle decreased significantly (P0.01).The replacement of artificial chordae was not complicated and it seemed to help to preserve a good relationship among leaflet tissues, chordae, and papillary muscles. We therefore suggest that the extensive use of PTFE artificial chordae appears to be a promising procedure for the repair of all kinds of mitral lesions causing mitral regurgitation.

Objective: Mechanical cardiac support system (MCSS) has been used for adult patients in postcardiotomy cardiogenic shock and has been shown to provide excellent oxygenation and hemodynamic support. However, MCSS has a number of disadvantages that include high incidence rate of complications (e.g. stroke, bleeding) and limited duration of sufficient support. The objective of this study is to identify peri-operative and postoperative factors for survival in patients having MCSS. Methods: From January 1991 to April 2001, MCSS has been applied to 22 adult patients in postcardiotomy cardiogenic shock. These patients’ charts were retrospectively reviewed. Results: Of 22 patients, 9 patients (41%) were successfully weaned, and 6 (27%) were hospital survivors. The duration of assist ranged from 21 to 211 hours (median 66 hours). In 7 (78%) out of 9 patients who could be weaned from MCSS, MCSS were required for less than 3 days. Major complications were reexploration for bleeding (18%), leg ischemia (45%), renal dysfunction (77%), liver dysfunction (59%), infection (31.8%), hypoxia due to lung dysfunction (36%) and cerebral dysfunction (41%). pH, base excess, HCO 3 − , urine output, transfused platelets at first 24 hours of MCSS and preoperative body surface area were significant predictors for survival. Conclusion: The indices of insufficient hemodynamic support such as progression of acidosis or poor urine output are significant predictors for early death. Early conversion from MCSS to long-term assist device, such as left ventricular assist device, should be considered when these factors are associated with poor cardiac recovery.

Cardiovascular surgery is challenging in patients who have previously undergone thoracoplasty because of severe chest deformity and impaired pulmonary function. We report a case of an octogenarian with prior left thoracoplasty, who successfully underwent surgical repair of an acute aortic dissection through a standard median sternotomy. We suggest that prior thoracoplasty might not necessarily be an exclusion criterion for aortic surgery in cases with adequate pulmonary function.

Recently, we have described a drug (cyclophosphamide [CP] plus busulfan [BU])-induced skin allograft tolerance in mice that can regularly overcome fully H-2-mismatched barriers. Using this method, we have investigated whether or not this regimen can prolong the survival of heart allografts and inhibit the development of posttransplant cardiac allograft vasculopathy (CAV).The components of the method are intravenous administration of 1 x 108 allogeneic spleen cells on day 0, intraperitoneal injection of 200 mg/kg of CP and 30 mg/kg of BU on day 2, and intravenous injection of T cell-depleted 1 x 107 allogeneic bone marrow cells from the same strain of mice on day 3. Heart grafting was performed on day 28. Chimerism in peripheral blood was followed by flow cytometric analysis, and histological analysis was performed at various times after grafting.In a fully major histocompatability complex (MHC)-mismatched combination of B10.D2 (H-2d, IE+)--B10 (H-2b, IE-), stable, multilineage-mixed chimerism was observed permanently. B10.D2 heart grafts were accepted permanently in a donor-specific manner, and posttransplant CAV did not develop.These results demonstrated that the drug-induced tolerance recently established by us can regularly induce a long-lasting heart allograft tolerance without development of CAV.

A new method of mouse aortic graft transplantation into carotid artery was developed with cuff technique. By harvesting the descending aorta of the donor using a small Teflon cuff (external diameter 0.6 mm, internal diameter 0.4 mm) and super fine-tip forceps, and modifying the method of mouse heterotopic heart transplantation with cuff technique, donor descending aortic allografts could be interposed in the common carotid artery of recipient mice. Histological analysis demonstrated neither evidence of tissue damage nor intimal thickening in isograft implanted over 100 days. We strongly recommend that this new model of aortic transplantation in mice is a simple and useful technique for vascular transplantation research.

The results of previous studies indicate that only CD4+ T cells generated via the indirect pathway play an essential role in causing discordant skin xenograft rejection. The present study was conducted in an attempt to clarify further the roles of effector T cells generated via direct pathways on discordant xenograft rejection using CD45 exon-6 knockout (CD45-/-; C57BL/6 (B6): H-2b) mice. It has been strongly suggested that CD45 exon-6 knockout mice have profound impairment in T-cell functions via an indirect pathway. When human skin was grafted onto untreated normal C57BL/6 (B6; H-2b) mice, rejection occurred within 12 days; however, in the CD45 exon-6 knockout mice, the grafts lasted for slightly longer as in fully allogeneic C3H (H-2k) skin rejection, with a mean survival time +/- SD of 19.4 +/- 1.5 days and median survival times of 19 days. The difference in survival periods between the human and C3H skin grafts in the CD45 knockout mice was not statistically significant. Both CD4+ and CD8+ T cells seemed activated in the spleens of these CD45 exon-6 knockout mice 10 days after the human skin grafting. These results suggest that effector T cells generated via a direct pathway can cause discordant skin xenograft rejection, and that CD45 exon-6 knockout mice can generate effector T cells via a direct pathway to reject discordant skin xenografts, similarly to fully allogeneic skin allografts.