Antibody-mediated T-cell reduction or increased levels of chimerism overcome resistance to cyclophosphamide-induced tolerance in NKT-deficient mice.

We reported that invariant NKT-cell knockout (iNKT KO) mice are resistant to the induction of intrathymic chimerism and clonal deletion in the cyclophosphamide (CP)-induced tolerance system (CPS). However, another report shows that clonal deletion with chimerism may be intact in iNKT KO recipients in a bone marrow transplantation model. We also reported that pretreatment with anti-Thy1.2 mAb, which reduces the number of T cells and iNKT cells, promotes allograft tolerance across H-2 barriers in the CPS. In this study, we evaluated the efficacy of T-cell depletion in the CPS, and the relationship between the role played by iNKT cells in central tolerance and mixed chimerism. BALB/c (H-2(d)) wild-type, or iNKT KO (Jalpha18(-/-)) mice were pretreated with 20-100 microg of anti-Thy1.2 mAb and given 10(8) donor DBA/2 (H-2(d)) spleen cells on Day 0, and 200 mg/kg CP on Day 2. Pretreatment with T-cell depletion resulted in higher levels of mixed chimerism, increased intrathymic clonal deletion of donor-reactive cells, and the induction of skin graft tolerance in iNKT KO recipients in CPS. This suggests that the high levels of mixed chimerism overcame the resistance to CP-induced tolerance in iNKT KO mice. Consistently, the enhancement of mixed chimerism by injection of tolerant donor spleen cells (SC) rendered iNKT KO recipients susceptible to CP-induced tolerance. These results suggest that iNKT-cell-mediated immunoregulation of central tolerance is evident at low levels of peripheral mixed chimerism in the CPS.

Effects of lipopolysaccharide on the induction of mixed chimerism in cyclophosphamide-induced tolerance.

Cyclophosphamide (CP)-induced tolerance is a mixed chimerism-based tolerance and is one of the strategies used to induce transplant tolerance. Toll-like receptor (TLR) agonists are reportedly able to abrogate the induction of tolerance by activating alloreactive T cells, or by inhibiting Treg cells. However, little is known about the effect of the immune response mediated by TLR on mixed chimerism-based tolerance protocols. In this study, we evaluated the influence of lipopolysaccharide (LPS), which is best known as an TLR4 agonist, on CP-induced tolerance. BALB/c (H-2(d)) mice received a conditioning regimen consisting of 10(8) donor DBA/2 (H-2(d)) spleen cells (SC) on day 0 and 200 mg/kg CP on day 2. A single dose of 20 microg LPS was injected on day -2, 0, 7, or 35. Our results showed that LPS infusion at any time point resulted in chronic rejection of donor skin grafts and the abrogation of mixed chimerism in 33-60% of recipients. We found a correlation between skin graft acceptance and higher levels of mixed chimerism. Flow cytometric analysis revealed that donor-reactive T cells were permanently eliminated, regardless of LPS infusion. In conclusion, LPS-infusion had little influence on the immune response of donor-reactive T cells, but had a significant effect on the induction and maintenance of mixed chimerism in CP-induced tolerance.

Application of chimerism-based drug-induced tolerance to rat into mouse xenotransplantation.

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.

[Docetaxel was effective as neoadjuvant chemotherapy for patients after failure of trans-arterial neoadjuvant chemotherapy with CEF in 2 cases of advanced breast cancer].

Docetaxel was effective as a second line neoadjuvant chemotherapy after failure of cyclophosphamide, epirubicin and 5-FU (CEF) in 2 cases of breast cancer. In Case 1, 4 cycles of trans-arterial neoadjuvant chemotherapy of docetaxel showed a PR effect after failure of 2 cycles of trans-arterial neoadjuvant chemotherapy with CEF. This patient died of pleuritis carcinomatosa 18 months after surgery for breast cancer (latissimus dorsi muscle myocutaneous flap after radical mastectomy). In Case 2, 6 cycles of neoadjuvant venous drip infusion of docetaxel resulted in a CR effect after failure of 2 cycles of transarterial neoadjuvant chemotherapy with CEF. This patient is alive and disease-free 27 months after the operation for breast cancer (same operation as for Case 1). Docetaxel was effective as neoadjuvant chemotherapy for patients after failure of trans-arterial neoadjuvant chemotherapy with CEF.

Early and late results of total correction of congenital cardiac anomalies in infancy.

OBJECTIVE: We evaluated long-term results of surgical correction of congenital cardiac anomalies in infancy. METHODS: We reviewed cases of 856 patients who underwent complete correction of major cardiac anomalies in the first year of life during last 24 years at our institution, and analyzed results. Surgery involved ventricular septal defect (n = 453), tetralogy of Fallot (n = 92), atrioventricular canal defect (n = 93), and complete transposition of the great arteries (n = 218). RESULTS: Operative mortality was 2.2% in ventricular septal defect, 0% in tetralogy of Fallot, 8.6% in atrioventricular canal defect, and 4.1% in complete transposition of the great arteries. Freedom from reoperation at 20 years was 96.5 +/- 2.0% and actuarial survival was 94.2 +/- 1.3% in ventricular septal defect. Freedom from reoperation at 15 years was 90.5 +/- 3.9% in tetralogy of Fallot and 86.6 +/- 4.4% in atrioventricular canal defect. Actuarial survival at 15 years was 97.8 +/- 1.6% in tetralogy of Fallot, 85.7 +/- 3.7% in atrioventricular canal defect, and 89.9 +/- 2.2% in complete transposition of the great arteries. Actuarial survival in complete transposition of the great arteries was significantly better in arterial than in atrial switch operations. CONCLUSIONS: Total correction of ventricular septal defect, tetralogy of Fallot, atrioventricular canal defect, and complete transposition of the great arteries in infancy was conducted safely, but the incidence of reoperation in late follow-up must be reduced.

Collagen formation at the tooth-cell interface: comparative ultrastructural study on the effect of partial demineralization of cementum with dentin.

In order to compare the effect of partial demineralization with root planing and partial demineralization of cementum with that of dentin on healing, the ultrastructural morphology of the interface between the layer of human periodontal ligament-derived, fibroblast-like cells (HPF) and the treated root surface was studied in an in vitro culture system. Sixty (60) pairs made from transversally-cut root slices, 500 microns thick, were obtained from extracted human periodontally diseased teeth. Thirty (30) pairs of the root slices were preliminarily root planed (RP). The remaining half were root planed and then partially demineralized in a solution of citric acid (RP+CA). The opposite surface of paired slices was made uniform by using either cementum or dentin. Consequently, all root slices were classified into four experimental groups: RP-cementum and RP-cementum pairs (group 1), RP-dentin and RP-dentin pairs (group 2), RP+CA-cementum and RP+CA-cementum pairs (group 3), and RP+CA-dentin and RP+CA-dentin pairs (group 4). Each pair of root slices was placed on the floor of a 35-mm culture dish. HPF were seeded at a concentration of 4 x 10(5) cells/dish. Co-cultures of HPF and the root slices were examined using phase contrast and electron microscope after 4, 6, and 10 weeks. Electron-dense material covered non-demineralized root surfaces and the lining cells in accumulating cell layers were oriented parallel to the root surface and attached to the material in groups 1 and 2.(ABSTRACT TRUNCATED AT 250 WORDS)