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Biomedical subjects

R Abe

Publications and source records attributed to R Abe.

At least 91 records · Page 5Linked to original sources

Tamoxifen-induced apoptosis in breast cancer cells relates to down-regulation of bcl-2, but not bax and bcl-X(L), without alteration of p53 protein levels.

Tamoxifen (TAM) has been shown to induce apoptosis in breast cancer cells. bcl-2 family genes, which can interact with each other, have been shown to interfere with apoptosis after various stimuli. In this study, we investigated the effects of TAM on bcl-2 family gene products bcl-2, bax, and bcl-X(L) and on p53 levels in estrogen receptor-positive MCF-7 breast cancer cells. We found that TAM induced time- and concentration-dependent down-regulation of bcl-2 at both the mRNA and protein level. Down-regulation of bcl-2 correlated with TAM-induced apoptosis. In addition, estradiol treatment significantly increased bcl-2 protein expression and blocked the reduction of bcl-2 by TAM. TAM did not, however, affect bax, bcl-X(L), or p53 expression at the mRNA or protein level. Our results demonstrate that TAM can induce apoptosis in a time- and dose-dependent manner by modulating bcl-2 levels in breast cancer cells, and down-regulation of bcl-2 induced by TAM was not accompanied by alterations in p53 levels.

Antineoplastic Agents, Hormonal↗

Immunohistochemical Image Analysis of Estrogen and Progesterone Receptors in Breast Cancer.

BACKGROUND: Recently objective quantification of immunohistochemical estrogenreceptor (ER) and progesterone receptor (PgR) staining in breast cancer by image cytometry has been predominantly performed by measuring the area of positivelystained cells. However, in sample preparations of immunostained hormone receptors, both the stained area and the intensity of staining vary. In this study, we performed quantification of the stained area by measuring, tailing intensity using image cytometry. METHODS: Quantitative analysis of ER and PgR immunohistochemistry was performed using image cytometry. The obtained values were presented as % of positive staining (% PS). Comparison of % PS with values obtained by EIA and with clinicopathological features was performed. RESULTS: The % PS values and the natural logarithm of the EIA levels of the hormone receptors showed a significant positive correlation for both ER and PgR. The concordance of the results obtained by the two methods was 96.3% for ER and 73.7% for PgR. The ER-% PS values of postmenopausal patients were significantly higher than those of premenopausal patients, whereas the PgR-% PS values of the former group were significantly lower than those of the latter group. CONCLUSION: The quantification of ER and PgR in immunostained preparations using % PS as a parameter was reproducible and showed a high correlation with values obtained by EIA. It was shown that only menopausal status affects hormone receptor levels when analyzing the relationship between % PS measurements and clinicopathological features.

Journal Article↗

Involvement of CD40 ligand-CD40 and CTLA4-B7 pathways in murine acute graft-versus-host disease induced by allogeneic T cells lacking CD28.

The blockade of B7, using B7 antagonists such as anti-CD80 and/or -CD86 mAbs or CTLA4Ig in vivo, has been shown to induce an efficient suppression of T cell-mediated immune responses in allograft, allergy, and autoimmune models. However, this treatment does not result in complete tolerance. In this study, we examined CD28-B7-independent activation pathways in the pathogenesis of graft-vs-host disease (GVHD) using allogeneic T cells from CD28-deficient mice. Acute GVHD was induced in the absence of CD28 on donor T cells and its manifestations were obvious in the lymphoid tissues. The CD28-independent GVHD was significantly improved by treatment with anti-CD40 ligand (CD40L) mAb. In contrast, treatment with anti-CD80 plus anti-CD86 mAbs exacerbated the clinical manifestations of GVHD and increased the T cell response against host alloantigen, resulting in the expression of CTLA4, CD40L, and CD25 on splenic T cells. These data suggested that the CD40L-CD40 pathway significantly contributed to the CD28-independent pathogenesis of acute GVHD, whereas the CTLA4-B7 pathway acted protectively in the development of GVHD. These results imply that selectively blockading CD28, instead of disrupting both CD28 and CTLA4, would be a better therapeutic strategy for GVHD. Additionally, the simultaneous use of CD40 antagonists may be advantageous.

Abatacept↗

Cross-linking CD21/CD35 or CD19 increases both B7-1 and B7-2 expression on murine splenic B cells.

Activation of the complement cascade and ligation of complement C3 receptors on B cells represent an important bridge between innate and Ag-specific acquired immunity. We show here that cross-linking of mouse CD21 (complement receptor type 2, CR2, C3d receptor) and CD35 (complement receptor type 1, CR1, C3b/C4b receptor) or co-cross-linking of CD21/CD35 and surface IgM rapidly up-regulates both B7-1 and B7-2 expression on murine resting splenic B cells. CD21/CD35-mediated up-regulation of both B7-1 and B7-2 expression is observed within 14 h, while other stimuli up-regulate only B7-2 but not B7-1 at this early time point. Consistent with the increase in B7 levels, BALB/c B cells on which surface IgM and CD21/CD35 have been co-cross-linked stimulate C57BL/6 T cells more effectively than controls. This CD21/CD35-enhanced allogeneic MLR is blocked nearly completely by anti-B7-2 mAbs and partially by anti-B7-1 mAbs. In addition, cross-linking of CD19, which is physically associated with CD21/CD35, leads to increased B7-1 and B7-2 expression. These data suggest that CD21/CD35 ligation results in enhanced B cell Ag presentation using costimulatory mechanisms shared with other activators and thus works cooperatively in this process. Rapid up-regulation of B7-1 expression, a unique response to CD21/CD35 and CD19 cross-linking, may be a particularly important effect of C3-containing ligands. We propose that CD21/CD35- and CD19-mediated B7-1 and B7-2 up-regulation is an important mechanism by which complement activation links innate and acquired immunity.

Animals↗

Dopamine induces apoptosis through an oxidation-involved SAPK/JNK activation pathway.

Dopamine (DA) is a neurotransmitter, but it also exerts a neurotoxic effect under certain pathological conditions, including age-related neurodegeneration such as Parkinson's disease. By using both the 293 cell line and primary neonatal rat postmitotic striatal neuron cultures, we show here that DA induces apoptosis in a time- and concentration-dependent manner. Concomitant with the apoptosis, DA activates the JNK pathway, including increases in JNK activity, phosphorylation of c-Jun, and subsequent increase in c-Jun protein. This DA-induced JNK activation precedes apoptosis and is persistently sustained during the process of apoptosis. Transient expression of a dominant negative mutant SEK1(Lys --> Arg), an upstream kinase of JNK, prevents both DA-induced JNK activation and apoptosis. A dominant negative c-Jun mutant FLAGDelta169 also reduces DA-induced apoptotic cell death. Anti-oxidants N-acetylcysteine and catalase, which serve as scavengers of reactive oxygen species generated by metabolic DA oxidation, effectively block DA-induced JNK activation and subsequent apoptosis. Thus, our data suggest that DA triggers an apoptotic death program through an oxidative stress-involved JNK activation signaling pathway. Given the fact that the anti-oxidative defense system declines during aging, this molecular event may be implicated in the age-related striatal neuronal cell loss and age-related dopaminergic neurodegenerative disorders, such as Parkinson's and Huntington's diseases.

Animals↗

A fundamental difference in the capacity to induce proliferation of naive T cells between CD28 and other co-stimulatory molecules.

T cell activation requires two signals: a signal from the TCR and a co-stimulatory signal provided by antigen-presenting cells (APC). In addition to CD28, multiple molecules on the T cell have been described to deliver co-stimulatory signals. Here, we investigated whether there exist quantitative or qualitative differences in the co-stimulatory capacity between CD28 and other molecules. Anti-CD28 monoclonal antibody (mAb) and mAb against CD5, CD9, CD2, CD44 or CD11a all induced activation of naive T cells in the absence of APC when co-immobilized with a submitogenic dose of anti-CD3 mAb. [3H]Thymidine incorporation determined 2 days after co-stimulation was all comparable. In contrast to progressive T cell proliferation induced by CD28 co-stimulation, co-stimulation by other T cell molecules led to a decrease in viable cell recovery along with the induction of apoptosis of once activated T cells. This was associated with a striking difference in IL-2 production; CD28 co-stimulation induced progressively increasing IL-2 production, whereas co-stimulation by other molecules produced limited amounts of IL-2. Addition of recombinant IL-2 to the latter cultures corrected the induction of apoptosis, resulting in levels of cellular proliferation comparable to those observed for CD28 co-stimulation. These results indicate that a fundamental difference exists in the nature of co-stimulation between CD28 and other molecules, which can be evaluated by the levels of IL-2 production, but not simply by [3H]thymidine incorporation.

Animals↗

Obstructive Ileus caused by blood clot after emergency total gastrectomy in a patient with hemophilia A: report of a case.

We report herein the extremely unusual case of a patient with hemophilia A who developed a hematoma ileus soon after undergoing an emergency total gastrectomy. Postoperatively, the patient was found to have an obstruction in the small intestine that was difficult to differentiate from intussusception. Reoperation revealed the cause of the obstruction to be a large blood clot. This case report serves to demonstrate that careful hemostasis and observation during surgery is essential in patients with hemophilia.

Anastomosis, Surgical↗

Inhibitory effects of prostaglandin D2 against the proliferation of human colon cancer cell lines and hepatic metastasis from colorectal cancer.

The inhibitory action of prostaglandin D2 (PGD2) and its effect on the cell cycle were examined in cell lines SW480 and LS174T of human colon cancer. The growth of the cell lines were assessed 24 h and 48 h after the addition of 1.0 microgram/ml and 10.0 micrograms/ml PGD2. The growth of SW480 cells was inhibited 48 h, but not 24 h, after the addition of 1.0 microgram/ml, and 24 h and 48 h after the addition of 10.0 micrograms/ml, while that of LS174T was inhibited by both doses after 24 h and 48 h. S-Phase DNA synthesis in the SW480 cells was significantly blocked 24 h after the addition of 10.0 micrograms/ml PGD2. The cell cycle of LS174T cells was arrested at the G0 + G1 phase 24 h after the addition of 1.0 microgram/ml and 10.0 micrograms/ml PGD2. The correlation between hepatic metastasis and PGD2 concentration in human cancer tissue was examined. The mean value of PGD2 concentrations in the primary cancer tissue was significantly lower in the hepatic metastasis group than that in the group without hepatic metastasis. These findings suggest that measuring the PGD2 in cancer tissue may be useful for detecting and predicting the hepatic metastasis from human colorectal cancer.

Biomarkers, Tumor↗

Composite glandular-neuroendocrine carcinoma of the hilar bile duct: report of a case.

We report herein an unusual case of a composite glandular-neuroendocrine carcinoma of the hilar bile duct. A 71-year-old Japanese woman was admitted to our hospital suffering from general fatigue, progressive jaundice, and a high fever. Computed tomography and angiography findings revealed a solid hypervascular mass in the hepatic hilus. Thus, a subsegmentectomy of the liver (S4, S5) and bile duct resection with lymph node dissection were performed. A tumor measuring 6.0 x 3.0 cm was found to be located in the bile duct of the hepatic hilus. Histologically, the tumor was composed of well-differentiated adenocarcinoma and small cell neuroendocrine carcinoma cells, with a histological transition between the two components. Grimelius' method revealed the presence of diffuse positive tumor cells in neuroendocrine carcinoma. The neuroendocrine tumor cells were also diffusely immunoreactive to chromogranin A. To the best of our knowledge, only 22 previous cases of composite glandular-neuroendocrine carcinoma in the biliary tract have been reported; however, this is the first case report of a clearly composite tumor of the hilar bile duct.

Adenocarcinoma↗

High proportion of missense mutations of the BRCA1 and BRCA2 genes in Japanese breast cancer families.

Mutations in either of two recently identified genes, BRCA1 and BRCA2, are thought to be responsible for approximately two-thirds of all cases of autosomal-dominantly inherited breast cancer. To examine the nature and frequency of BRCA1 and BRCA2 mutations in Japanese families exhibiting a high incidence of breast cancer, we screened 78 unrelated families in this category for mutations of these two genes. Examining the entire coding sequences as well as exon-intron boundaries of both genes by polymerase chain reaction (PCR) single-strand conformation polymorphism (SSCP) and multiplex-SSCP analysis, we identified possible disease-causing alterations in BRCA1 among affected members of 15 families and in BRCA2 in another 14 families. In 15 of those 29 families, the affected individuals carried missense mutations, although most germline mutations reported worldwide have been deletions or nonsense mutations. Our results, indicating that missense mutations of BRCA1 and BRCA2 tend to predominate over frameshifts or nonsense mutations in Japanese breast cancer families, will contribute significantly to an understanding of mammary tumorigenesis in Japan, and will be of vital importance for future genetic testing.

BRCA2 Protein↗

Endogenous glucocorticoids decrease the acinar cell sensitivity to apoptosis during cerulein pancreatitis in rats.

BACKGROUND & AIMS: We recently showed that activation of the hypothalamus-pituitary-adrenal axis may mitigate the progress of acute pancreatitis. To clarify the mechanism, the role of endogenous glucocorticoids in pancreatic acinar cell death was examined. METHODS: The occurrence of apoptosis was studied in adrenalectomized or sham-operated rats with or without cerulein-induced pancreatitis. The effects of RU38486, a glucocorticoid-receptor antagonist, on the survival of cultured acinar cells (AR42J) were also examined. RESULTS: Adrenalectomy caused increases in terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick-end labeling (TUNEL) of acinar nuclei depending on the time after adrenalectomy but not of other cell types in the pancreas and in other digestive organs. Electron microscopy showed the characteristic features of apoptosis in the TUNEL-labeled acinar cells. In cerulein pancreatitis of adrenalectomized rats, the TUNEL-labeled acinar nuclei increased remarkably depending on the time after cerulein infusion. Replacement of glucocorticoids blocked the occurrence of apoptosis in these experiments. RU38486 induced dose dependently the apoptosis of AR42J cells. CONCLUSIONS: These results provide evidence that endogenous glucocorticoids are an important factor for acinar cell survival. Endogenous glucocorticoids may protect acinar cells by decreasing their sensitivity to the induction of cell death during acute pancreatitis.

Acute Disease↗

Isolation and characterization of cDNA encoding chicken egg yolk aminopeptidase Ey.

Aminopeptidase Ey (EC 3.4.11.20) from chicken (Gallus gallus domesticus) egg yolk is a homodimeric exopeptidase with a broad specificity for N-terminal amino acid residues at P1 position of the substrate. Aminopeptidase Ey is a 300-k metalloexopeptidase, containing 1.0 g atom of zinc per mole of a subunit with a relative molecular mass of 150 k. A full-length cDNA was cloned from chicken (female) liver cDNA library. Analysis of the 3196-base pairs (bp) nucleotide sequence of the cDNA revealed a single open reading frame coding for 967 amino acid residues. The coding region of aminopeptidase Ey gene, apdE, occupies 2901 bp of the cDNA. The predicted amino acid sequence of the enzyme is 66, 65, 64 and 63% identical with those of aminopeptidases N (EC 3.4.11.2) from human, pig, rabbit and rat, respectively. Aminopeptidase Ey contains the metallo-binding sequence motif, His-Glu-Xaa-His, found in zinc metallopeptidases. Zinc binding sites, His-386, His-390 and Glu-409, and catalytic site, Glu-387, were conserved in the homologous aminopeptidases N.

Amino Acid Sequence↗

Phase II study of paclitaxel (BMS-181339) intravenously infused over 3 hours for advanced or metastatic breast cancer in Japan. BMS-181339 Breast Cancer Study Group.

A Phase II study of paclitaxel in patients with primary advanced or metastatic breast cancer was conducted by a cooperative study group consisting of 16 institutions in Japan. Paclitaxel at a dose of 210 mg/m2 was intravenously infused over 3 hours, along with premedication to prevent hypersensitivity reactions. The course was repeated at 21-day intervals. Of 62 eligible patients, 60 were evaluable for toxicity and 59 were evaluable for efficacy. Forty-five patients were previously treated with anthracyclines. Twenty-one of 59 patients (35.6%) had a major objective response including 2 CRs and 19 PRs (95% confidence interval, 23.6-49.1%). A response rate of 35.5% (CR1, PR10) was observed in 31 patients refractory to the anthracyclines containing prior metastatic chemotherapy. Median (range) time was 41 (6-100) days to onset of and median duration of response was 125 (36-305) days. Toxicities included leukopenia (grade 3, 4: 67%), anemia (grade 1-3: 80%), thrombocytopenia (grade 1: 8%), alopecia (grade 3: 43%), peripheral neuropathy (grade 1-3: 93%), arthralgia (59%), myalgia (46%), nausea and vomiting (40%), fever (33%), allergic reaction (grade 3: 2%) and hypotension (grade 3: 5%). All toxicities were tolerable and manageable. Paclitaxel intravenously infused over 3 hours demonstrated a significant antitumor activity for metastatic breast cancer. Furthermore, paclitaxel exhibited non-cross resistance to anthracycline. Paclitaxel administered as a convenient 3-hour infusion is effective for patients with metastatic breast cancer and has an acceptable toxicity profile.

Adult↗

Cis-urocanic acid down-regulates histamine-mediated activation of adenylate cyclase in the pig epidermis.

Urocanic acid (UCA), one of the skin's major components for absorbing UV radiation, is present naturally in the stratum corneum as a trans-isomer. On absorption of UVB radiation either in vitro or in the skin, UCA undergoes trans- to cis-isomerization in a dose-dependent manner. Although the mechanism by which cis-UCA suppresses immunity remains unelucidated, recent studies have indicated that cis-UCA appears to inhibit the induction of cyclic AMP in fibroblasts, which suggests that this molecule plays an active role in modifications to the skin. Here, we report that although neither trans-UCA nor cis-UCA increases cyclic AMP in the pig epidermis, cis-UCA actively down-regulates the increase of cyclic AMP induced by histamine. The effects of cis-UCA on the pig epidermis are revealed through the modulation of the effects caused by histamine. These findings suggest that in the pig epidermis, the initial biochemical and cellular event for UVB-induced immune suppression--that is, the step immediately following the isomerization of trans-UCA to cis-UCA--is down-regulation of cyclic AMP brought about by the activity of cis-UCA.

Adenylyl Cyclases↗

The role of B7-CD28 co-stimulation in tumor rejection.

The role of B7 co-stimulatory signaling in in vivo tumor rejection remains incompletely characterized. In particular, the relative competence of B7-1 (CD80) and B7-2 (CD86) to provide effective co-stimulus is not well defined, and the identification of the T cell co-stimulatory receptor that mediates B7 co-stimulation in tumor rejection has not been addressed. These issues were studied by assessing rejection of B7-negative or B7-transfected tumor cells in CD28-expressing or CD28-deficient hosts. B7-negative EL4 tumor cells grew progressively in normal syngeneic C57BUL6 (B6) mice. In contrast EL4 cells transfected with either full length B7-1 or full length B7-2 were rejected, indicating that both B7-1 and B7-2 are competent to mediate rejection of EL4 tumor cells. Expression of truncated B7-1 or B7-2 products, with complete deletion of cytoplasmic domains, was as effective as expression of full length B7-1 or B7-2 in mediating rejection. In contrast to the rejection of B7-transfected EL4 cells observed in CD28-expressing syngeneic hosts, B7-1- and B7-2-positive EL4 cells as well as control EL4 cells grew progressively in CD28-deficient mice, demonstrating the requirement for host expression of CD28 in B7-mediated tumor rejection. These results indicate that interaction of host CD28 with co-stimulatory extracellular B7-1 or B7-2 ligands expressed on tumor cells can play a necessary role in mediating tumor rejection.

Age Factors↗

Lipopolysaccharide-induced desensitization to pancreatic edema formation in rat cerulein pancreatitis.

Previously we reported that prior administration of lipopolysaccharide (LPS) mitigates subsequently produced cerulein (Cn) pancreatitis. To clarify the mechanism further, the pathological features of Cn pancreatitis were examined in detail after treating rats with very low doses of LPS. LPS pretreatment reduced the formation of pancreatic edema during Cn pancreatitis in a dose- and time-dependent manner. In contrast, the elevation of serum amylase and the histological findings, including acinar cell vacuolization and infiltration of inflammatory cells, were not affected. The lowest dose of LPS, 500 ng/kg, was sufficient to inhibit pancreatic edema formation completely. LPS at a dose of 5 microg/kg was fully effective when it was given from 30 min to 12 h before the induction of pancreatitis. Pretreatment with tumor necrosis factor-alpha (TNF-alpha) inhibited the pancreatic edema in a manner similar to that of LPS. Moreover, the inhibitory effect of LPS was partially attenuated by the administration of anti-TNF-alpha antibody before the injection of LPS. Actinomycin D (0.5 mg/kg) abolished the effect of LPS, whereas cycloheximide (0.5 mg/kg) given alone reduced pancreatic edema formation during pancreatitis. From these results, it was concluded that very low doses of LPS can induce, partially via TNF-alpha, a state refractory to pancreatic edema formation during Cn pancreatitis, and this phenomenon seems to be regulated at the transcriptional level.

Animals↗