Quantum phase transition of the randomly diluted heisenberg antiferromagnet on a square lattice

Ground-state magnetic properties of the diluted Heisenberg antiferromagnet on a square lattice are investigated by means of the quantum Monte Carlo method with the continuous-time loop algorithm. It is found that the critical concentration of magnetic sites is independent of the spin size S, and equal to the two-dimensional percolation threshold. However, the existence of quantum fluctuations makes the critical exponents deviate from those of the classical percolation transition. Furthermore, we found that the transition is not universal, i.e., the critical exponents significantly depend on S.

Combined treatment with TNP-470 and 5-fluorouracil effectively inhibits growth of murine colon cancer cells in vitro and liver metastasis in vivo

The combined effects of TNP-470 (TNP), a semisynthetic analogue of fumagillin, and 5-fluorouracil (5FU), a representative chemotherapeutic agent for colorectal cancer, were investigated using murine colon 26 adenocarcinoma (CT 26) cells. In a cell-proliferation study in vitro, 50% inhibitory concentrations (IC50) were determined to be 5.2 microg/ml and 240 ng/ml for TNP and 5FU, respectively. When CT 26 cells were treated with TNP and 5FU in combination, a remarkable cytotoxic effect was obtained. Isobologram analysis revealed synergism of these two agents in inhibition of the cell growth. In vivo, using a dorsal air sac assay, we found that TNP significantly inhibited the CT 26-induced angiogenesis. In addition, the combination of TNP and 5FU exerted a synergistic anti-tumor effect in a model of hepatic metastasis by portal injection of CT 26 cells. Since TNP is known to exert inhibitory effects on tumor cell growth through suppression of cell cycle progress from the G1 to S phases as well as neovascularization, it is speculated that the treatment with TNP enhanced the anti-tumor effect of 5FU through suppression of the cell cycle and tumor-derived angiogenesis. Taken together, these results suggest that combined treatment with TNP and 5FU is potentially useful for inhibition of tumor cell growth and liver metastasis of colorectal cancer.

An antibody for macrophage migration inhibitory factor suppresses tumour growth and inhibits tumour-associated angiogenesis

To verify the role of macrophage migration inhibitory factor (MIF) in tumourigenesis, we examined the effect of an anti-MIF antibody on tumour growth and angiogenesis. We inoculated murine colon adenocarcinoma cell line colon 26 cells subcutaneously into the flank in BALB/c mice. After nine days, we treated tumour-bearing mice with an anti-rat MIF antibody by intraperitoneal injection on days 9, 11, 13, 15, 17, 19 and 21. We found significant inhibition of tumour growth by this treatment from day 15 to day 22. Next, we implanted a chamber filled with colon 26 cells, which only passes soluble factors, in the subcutaneous fascia of the flank, and treated mice with the anti-rat MIF antibody at days 1, 3 and 5. By histological examination at day 6, angiogenesis within the subcutaneous fascia in contact with the chamber was markedly suppressed. In vitro, we added an anti-human MIF antibody to human umbilical vein endothelial cells (HUVEC) to evaluate its effect on cell growth by measurement of [3H]thymidine incorporation. We observed that the anti-MIF antibody significantly suppressed [3H]thymidine uptake by HUVEC. These results suggest the possibility that MIF is involved in tumourigenesis via promotion of angiogenesis.

Distinct prognostic values of p53 mutations and loss of estrogen receptor and their cumulative effect in primary breast cancers

A total of 76 primary breast cancers were screened for p53 mutations using the yeast p53 functional assay, and the mutations were determined by DNA sequencing. Clonal mutations of p53 were detected in 30 tumors (39%). Immunohistochemical staining for nuclear p53 accumulation performed on the yeast assay-positive cases clearly differentiated missense mutations in the DNA binding domain (contact mutant; 17 cases) as positive stain and nonsense-type mutations or missense mutations that may affect 3D-structure of p53 protein (structural mutant; 13 cases) as negative stain. Enzyme immunoassay revealed loss of estrogen receptor in 36 tumors (50%). Prognostic values of p53 mutation and loss of estrogen receptor were evaluated after a median follow-up period of 44 months. p53 mutations were associated with a short overall survival (log rank test, p = 0.0319), whereas it was not related to disease-free (recurrence-free) survival. Contact mutants were associated with slightly shorter survival compared with structural mutants. Inversely, loss of estrogen receptor was associated with early recurrence (p = 0.0461) but not with short overall survival. The patients with tumors harboring both p53 mutation and loss of estrogen receptor had the poorest outcome (p = 0.0019 and 0.0075 for overall and disease-free survivals, respectively), suggesting independent and additive effects of the 2 factors. The independent role of the 2 factors was confirmed by a multivariate analysis using the Cox proportional hazard model stratified according to clinical tumor stages. Although preliminary, due to the small number of patients studied and the relatively short follow-up time, our results suggest that p53 mutations and loss of estrogen receptor cooperatively affect the prognosis of primary breast cancer patients.

Blocking the CD28-B7 T-cell costimulatory pathway abrogates the development of obliterative bronchiolitis in a murine heterotopic airway model

BACKGROUND

CTLA4IgG that binds to B7 effectively inhibits the signaling of CD28/B7 pathway and induces antigen-specific T-cell unresponsiveness in vitro and in vivo. We examined whether the development of obliterative bronchiolitis in a murine heterotopic airway transplantation model is T cell dependent and whether CTLA4IgG abrogates the development of obliterative bronchiolitis.

METHODS

Tracheae with main bronchi from C3H/He (H2k), BALB/C (H2d), or C57BL/6 (H2b) mice were transplanted heterotopically into subcutaneous pockets on the backs of BALB/C or BALB/C nu/nu mice on day 0. Recipient mice were untreated or intraperitoneally treated with either CTLA4IgG or human IgG with different time and dose schedules.

RESULTS

The development of obliterative bronchiolitis, which leads to luminal obliteration by fibrous tissue in a murine heterotopic airway transplantation model, was T cell dependent and the development of obliterative bronchiolitis was significantly abrogated by the CTLA4IgG treatment. However, the normal ciliated columnar respiratory epithelial cells in allografts were lost and replaced by flattened attenuated epithelial cells even after the CTLA4IgG treatment. We further demonstrated that CTLA4IgG treatment did not result in the induction of donor-specific unresponsiveness.

CONCLUSIONS

We demonstrated that the development of obliterative bronchiolitis in a murine heterotopic airway model involves both CD28/B7-dependent and -independent processes. The luminal obliteration by fibrous tissue is clearly CD28/B7 dependent and can be inhibited by CTLA4IgG. The luminal obliteration of allografted trachea by fibrous tissues and the loss of ciliated columnar respiratory epithelial cells represent distinct disease processes.

First case of cadaveric liver transplantation in Japan

The first case of liver transplantation from a brain-dead donor in Japan is described. The recipient was a 43-year-old man with familial amyloid polyneuropathy who manifested various neuropathic symptoms and autonomic dysfunction at the time of transplantation. The graft had three arteries, for which a single trunk was created at the back table. A side-to-side cavacaval anastomosis was performed as an outflow reconstruction. To avoid portal congestion, a temporary shunt between the right posterior branch of the portal vein and the vena cava was constructed, instead of a venovenous bypass. The graft preservation time was 7.2 h and the operation time was 12.2 h. Although sufficient blood flow in the hepatic artery, portal vein, and hepatic vein was confirmed intra- and postoperatively, using Doppler ultrasound, transient graft dysfunction was observed immediately after surgery, but there was spontaneous improvement. The patient was discharged 100 days after transplantation.

Splenectomy in haemophagocytic lymphohistiocytosis: report of histopathological changes with CD19+ B-cell depletion and therapeutic results

The pathogenesis of haemophagocytic lymphohistiocytosis (HLH) in children without a known familial pattern of inheritance is often difficult to establish. Splenic enlargement, one of the main clinical findings in this disorder, has led to the use of splenectomy for uncontrollable coagulopathy, persistent cytopenia or both. This procedure is also thought to be a useful tool in making a differential diagnosis in cases of the immunochemotherapy-resistant HLH. We report here five cases of splenectomized childhood HLH, in which subsets of mononuclear spleen cells were analysed either by flow cytometry or immunohistochemistry, and the results were compared with those from cases of hereditary spherocytosis (controls). There was a statistically significant depletion of CD19+ B cells in the HLH cases (3.8 +/- 3.2% vs. 52.6 +/- 4.5%, P < 0. 0001) associated with an increase of T cells in three cases and of natural killer cells in another. The histopathological findings included atrophic white pulps, B-cell depletion with fibrosis and haemosiderosis in all five cases. Despite temporary therapeutic benefits, three of the HLH patients had a rapidly deteriorating post-splenectomy course and all three eventually died. These results demonstrate striking depletion of B cells in the enlarged spleens of children with HLH, which may be an intrinsic feature of HLH pathogenesis. Further study is needed to establish the therapeutic value of splenectomy in this disease.

FK506-induced intractable leukoencephalopathy following allogeneic bone marrow transplantation

FK506-related leukoencephalopathy has been reported to be reversible and readily treated by discontinuation or reduction of FK506. We describe two pediatric cases of FK506-related leukoencephalopathy following allogeneic bone marrow transplantation, which could not be readily controlled. These cases show that FK506-related leukoencephalopathy is not always reversible, and patients may develop epilepsy. Bone Marrow Transplantation (2000) 25, 331-334.

Sequential observation of liver cell regeneration after massive hepatic necrosis in auxiliary partial orthotopic liver transplantation

The morphogenesis of hepatocytes after massive hepatic necrosis to recovery through liver cell regeneration has not been fully understood. Sequential biopsies were performed on the native liver of a 22-year-old man who underwent auxiliary partial orthotopic liver transplantation 1 month after fulminant hepatitis. Auxiliary partial orthotopic liver transplantation was successful, and the biopsy samples permitted us to examine the regenerating process of hepatocytes after massive necrosis. At the time of auxiliary partial orthotopic liver transplantation (postoperative day 0), 95% of hepatocytes were lost and a few ductules were found in the portal areas. The ductules stained with cytokeratin 19. At postoperative day 7, the ductules began to increase in size and number and became dilated over a period of 1 month, when individual hepatocytes with clear cytoplasm appeared from the ductules. As the differentiation of hepatocytes increased, the expression of cytokeratin 19 was found to decrease. From 2 to 3 months, all of the ductules were transformed into hepatocytes, and they began to form round cell clusters. From 3 to 6 months, the round cell clusters became organized into trabecula with fibrosis. From 6 to 12 months, a lobular architecture was established, and by 14 months, the necrotic liver was fully recovered to normal. This study by examination of sequential biopsies demonstrates the progression of the regenerating process from total hepatic necrosis to complete recovery.

Prolongation of canine liver allograft survival by a novel immunosuppressant, FTY720: effect of monotherapy and combined treatment with conventional drugs

BACKGROUND

The immunosuppressive effect and other properties of a novel immunosuppressant, FTY720, have been studied mostly in the experimental transplantation of various extrahepatic organs. In this experiment, we evaluated the antirejection potency and adverse effects of this agent on liver grafts using a canine liver transplantation model.

METHODS

Forty-eight orthotopic liver transplantations were performed by the standard technique under a veno-venous bypass. Liver recipients were divided into two studies: a single-dose study with FTY720 at various doses and a combined dose study with conventional immunosuppressants (cyclosporine or tacrolimus) alone and combined with FTY720. Survival, biochemical and hematological tests, blood levels of immunosuppressants, and postmortem histology were determined.

RESULTS

The median survival of untreated control animals was 9 days, whereas treatment with FTY720 at a dose of 0.1 mg/kg/day prolonged graft survival to 49.5 days. FTY720 at 1 mg/kg/day showed a slight but insignificant prolongation to 16 days, but when the dose was increased to 5 mg/kg/day, the graft was rejected at 10 days. The combination of FTY720, 0.1 mg/kg/day, with a subtherapeutic dose of cyclosporine, 5 mg/kg/ day, prolonged median animal survival from 40 days with cyclosporine alone to 74 days. A combination of FTY720 (0.1 mg/kg/day) with tacrolimus (0.5 mg/kg/ day) compromised animal survival, reducing survival from 83.5 days with tacrolimus alone to 30.5 days due to infectious complication and emaciation by overimmunosuppression. No evident drug-induced side effects were observed.

CONCLUSIONS

FTY720 has a potent immunosuppressive effect when used alone at 0.1 mg/kg/day in canine liver transplantation. FTY720 is a promising candidate for future clinical application in orthotopic liver transplantation.

Distinct prognostic values of p53 mutations and loss of estrogen receptor and their cumulative effect in primary breast cancers

A total of 76 primary breast cancers were screened for p53 mutations using the yeast p53 functional assay, and the mutations were determined by DNA sequencing. Clonal mutations of p53 were detected in 30 tumors (39%). Immunohistochemical staining for nuclear p53 accumulation performed on the yeast assay-positive cases clearly differentiated missense mutations in the DNA binding domain (contact mutant; 17 cases) as positive stain and nonsense-type mutations or missense mutations that may affect 3D-structure of p53 protein (structural mutant; 13 cases) as negative stain. Enzyme immunoassay revealed loss of estrogen receptor in 36 tumors (50%). Prognostic values of p53 mutation and loss of estrogen receptor were evaluated after a median follow-up period of 44 months. p53 mutations were associated with a short overall survival (log rank test, p = 0.0319), whereas it was not related to disease-free (recurrence-free) survival. Contact mutants were associated with slightly shorter survival compared with structural mutants. Inversely, loss of estrogen receptor was associated with early recurrence (p = 0.0461) but not with short overall survival. The patients with tumors harboring both p53 mutation and loss of estrogen receptor had the poorest outcome (p = 0.0019 and 0.0075 for overall and disease-free survivals, respectively), suggesting independent and additive effects of the 2 factors. The independent role of the 2 factors was confirmed by a multivariate analysis using the Cox proportional hazard model stratified according to clinical tumor stages. Although preliminary, due to the small number of patients studied and the relatively short follow-up time, our results suggest that p53 mutations and loss of estrogen receptor cooperatively affect the prognosis of primary breast cancer patients.

Cold preservation of the human colon and ileum with University of Wisconsin solution

The inclusion of the colon in the intestinal graft resulted in worsening patient and graft outcome and increased the incidence of infection and rejection. In this study, we examine the role of ischemia on the barrier function of the epithelium during cold ischemia. Samples were collected from 15 harvested and transplanted human donor grafts (colon, 10; ileum, 6), which were immersed in University of Wisconsin (UW) solution. Ischemia (6, 12, 24, and 48 h) and reoxygenation were performed to evaluate the mucosal electrical status using the Ussing chamber technique. The functions of enterocytes and crypt cells were tested by glucose and theophylline challenge. Modified Park's classification was applied to evaluate the severity of mucosal damage under light microscopy. The colon had higher levels of baseline potential difference, short-circuit current, and resistance than the ileum during 6 48 h of ischemia. Colonic epithelial cells responded well to theophylline stimulation at 24 h of ischemia, while there was no ileal response. The colonic mucosa was histopathologically well preserved in UW solution for 48 h, and mucosal damage induced by reoxygenation was less than in the ileum. In conclusion, electrophysiologically and histopathologically, the colon is less susceptible to cold preservation damage than the ileum during storage with UW solution.

Effect of sliding locus on subsurface crack formation in ultra-high-molecular-weight polyethylene knee component

The objective of this study was to evaluate the effect of sliding locus on fatigue destruction of ultra-high-molecular-weight polyethylene (UHMWPE) in order to design a durable total knee arthroplasty (TKA) articulation. Two-dimensional sliding fatigue testing was performed under two simplified patterns of articulating interface sliding locus. Scanning acoustic tomography (SAT) was used for observation of subsurface cracks in UHMWPE specimens. A high rate of subsurface crack formation was observed when the movement was reciprocated on two different loci, in contrast with that on a single linear locus. This finding suggests that crack formation or propagation in UHMWPE components is accelerated not only by the compressive stress but also by complicated articulating movement locus.

Hemophagocytosis by leukemic blasts in a case of acute megakaryoblastic leukemia with t(16;21)(p11;q22)

We report the case of a 2-year-3-month-old boy with acute megakaryoblastic leukemia showing hemophagocytosis by leukemic blasts. The chromosome analysis of his bone marrow revealed t(16;21)(p11;q22). In addition to the present case, we found 4 other acute myeloid leukemia (AML) cases associated with hemophagocytosis and t(16;21)(p11;q22) in the literature, of which 3 were megakaryoblastic. Although the syndrome of AML with FAB-M4/5 morphology, t(8;16)(p11;p13), and erythrophagocytosis is well known, leukemic blasts of FAB-M7 morphology showing t(16;21)(p11;q22) may be underscored for their phagocytic activity.

Mutational analysis of p51A/TAp63gamma, a p53 homolog, in non-small cell lung cancer and breast cancer

p51, a novel family member of human p53, is a recently identified candidate tumor suppressor gene mapped at chromosome 3q28. Like p53, p51 was found to activate p21Waf1/Cip1 and to induce apoptosis. Since the DNA loss at 3q is reported in several cancers including non-small cell lung cancer (NSCLC), we screened for mutations in p51A (TAp63gamma), an isoform of p51 with short C-terminal region, in 80 NSCLCs as well as 85 breast cancers by RT-PCR single strand conformation polymorphism (SSCP) analysis and DNA sequencing. In NSCLCs, p51 was expressed in most tumors at variable levels and we found three missense and one silent mutations: Gln31His (transactivation domain) in two tumors, Ala148Pro (DNA-binding domain) and Leu248Leu (DNA-binding domain). In the tumor with Ala148Pro or the silent mutation, only the mutant gene appeared to be expressed. The modified FASAY method to test the ability of yeast expressing p51A cDNA to grow in medium lacking histidine has revealed that Ala148Pro results in a loss of function, while Gln31His does not. In contrast to NSCLC, no mutation was observed in all 85 breast cancers by the similar method. Our results suggest that, because of infrequent mutation, p51 may not be a Knudson type tumor suppressor in most NSCLCs and breast cancers. Nevertheless, in at least a part of NSCLC, p51 may play a certain role in carcinogenesis in a tissue-specific manner.

Identification of a transactivation activity in the COOH-terminal region of p73 which is impaired in the naturally occurring mutants found in human neuroblastomas

p73 is a recently cloned tumor suppressor gene that is highly homologous to p53, and the products of both possess similar functions in inhibiting cell growth and inducing apoptosis. Interestingly, the COOH-terminal region of p53 displays no significant homology with that of p73. Moreover, p73 has an additional segment at its COOH terminus. Recently, we have found two mutations of p73 with amino acid substitution (P405R and P425L) in primary neuroblastomas. Because the region (amino acid residues 382-491) contains a glutamine- and proline-rich domain, we hypothesized that it has a transactivation function, and the mutations found in tumors result in loss of function. To test it, we used the yeast GAL4 DNA-binding fusion system. Yeast transformants expressing a GAL4-p73(1-112) or a GAL4-p73alpha(380-513) fusion protein were grown in SD medium lacking histidine and tryptophan and exhibited a significant induction of beta-galactosidase activity. Transient transfection experiments revealed that both of fusion proteins could induce the chloramphenicol acetyltransferase activity in mammalian cells, indicating that the COOH-terminal as well as NH2-terminal regions of p73 had significantly high levels of transactivation activity. Furthermore, the former activity was severely impaired in two naturally occurring mutant forms found in neuroblastomas. These suggest that, unlike p53, p73 has two domains with transactivation function, one in the NH2-terminal region and the other in the COOH-terminal region. Loss of function mutation in the latter might be involved in tumorigenesis and/or tumor progression.

Prevention of lethal acute hepatic failure by antimacrophage migration inhibitory factor antibody in mice treated with bacille Calmette-Guerin and lipopolysaccharide

During the past few years, the biological functions of macrophage migration inhibitory factor (MIF) have been extensively re-evaluated. This has been found to be protein involved in broad-spectrum pathophysiological states as an inflammatory cytokine, pituitary-derived hormone, and glucocorticoid-induced immunomodulator. In this study, we investigated the involvement of this cytokine in the pathogenesis of lethal liver injury. Injecting a small dose of lipopolysaccharide (LPS) into bacille Calmette-Guerin (BCG)-primed Jcl:ICR mice caused a lethal hepatic injury mimicking fulminant hepatitis, in which 8 of 11 mice died within 48 hours (27% survival rate). Massive necrosis of parenchymal hepatocytes with marked mononuclear cell infiltration was observed by histological examination. Immunohistochemical analysis showed that most of the infiltrating mononuclear cells were Kupffer cells, macrophages, and, to a lesser extent, T cells. In parallel, serum aminotransferase and tumor necrosis factor-alpha (TNF-alpha) levels were increased. When an anti-MIF polyclonal antibody (0.3 mg IgG fraction/mouse) was intraperitoneally injected into mice primed with BCG, it protected them from acute hepatic failure (90% survival rate) with concomitant improvement of histological features. Injection of the antibody also suppressed the up-regulation of TNF-alpha and T-cell infiltration induced by LPS. Taken together, these results suggested that treatment with the anti-MIF antibody suppresses the endotoxin-induced fatal hepatic failure by regulating production of inflammatory cytokines and T-cell infiltration.

Anteroposterior and rotational movement of femur during knee flexion

This study was designed to analyze anteroposterior and rotational movement of femoral condyles during knee flexion from 15 degrees to 90 degrees using magnetic resonance imaging. After a pilot study, scans were made in 10 healthy male Japanese volunteers. When centers of the circular profiles of posterior femoral condyles were used as reference points, the medial and lateral femoral condyles displaced posteriorly 1.9 +/- 0.8 mm and 2.3 +/- 0.5 mm, respectively (mean +/- standard error). Duplicate examinations on two separate occasions revealed the accuracy of this procedure was in the range of 1 to 2 mm. These results have confirmed that femoral rollback occurs in the unloaded normal knee during flexion from 15 degrees to 90 degrees, but its magnitude is small (2 mm). The results obtained in this in vivo measurement of anteroposterior movement of the femoral condyles have relevance for total knee replacement design.