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Biomedical subjects

K Kawakami

Publications and source records attributed to K Kawakami.

At least 73 records · Page 4Linked to original sources
PubMed2001

[Theoretical construction of chemotherapeutic tactics for advanced or recurrent gastrointestinal carcinoma].

The anti-cancer effect of 5-fluorouracil (5-FU) is significantly affected by the intratumoral environment. Elevated expression of thymidylate synthase (TS), the target enzyme of 5-FU, and a lack of reduced folate or FdUMP results in insufficient inhibition of TS. Further, elevated expression of DPD in the tumor tissue results in a lack of FdUMP. TS-1, which contains tegafur and dihydroxypyridine (CDHP), a potent DPD inhibitor, is a promising anticancer drug. Isovorin has been available in Japan since autumn 1999. In cancer patients, folate deficiency may be derived from increased consumption and/or absorption disturbance of folate. In such situations, sufficient TS inhibition cannot be obtained if 5-FU is administered without supplementation of reduced folate. We describe in detail the metabolism of those substances in relation to the anticancer effect of 5-FU. Further, we show the theoretical construction of first-line and second-line chemotherapy with consideration of TS and DPD expression.

Antimetabolites, Antineoplastic↗
PubMed2001

The apolipoprotein E genotype influences the risk for vasospastic angina.

It has been suggested that people with the epsilon4 allele of the apolipoprotein E (apoE) polymorphism and the deletion (D) allele of the insertion (I/D) polymorphism of angiotensin-converting enzymes, are at a greater risk for coronary artery disease. However, only a few studies have examined the relationships between vasospastic angina (VSA) and genotype, especially with the apoE polymorphism. In the present study, 76 patients with VSA without significant fixed coronary artery stenosis, 149 patients with ischemic heart disease (IHD) who had 75% or more luminal diameter narrowing and 213 healthy subjects were enrolled. The odds ratio for VSA of the epsilon4 allele carriers relative to the epsilon3/3 allele subjects compared with subjects with IHD and control subjects combined was 0.44 (95% CI 0.21 to 0.93, P=0.021), and that compared with control subjects alone was 0.36 (95% CI 0.17 to 0.78, P=0.005), implying that the presence of the epsilon4 allele indicates resistance to the development of VSA. In contrast, people with the epsilon2 allele showed a tendency to develop VSA more frequently than did patients with IHD (P=0.009), although the frequency of the epsilon2 allele did not differ between patients with VSA and control subjects. On the other hand, no recessive and dominant effects of the D alleles on VSA were found. These findings suggest that the risk of the occurrence of VSA may be reduced by the epsilon4 allele and increased by the epsilon2 allele. The ApoE polymorphism may be associated with IHD and VSA, probably due to the modulation of lipid metabolism.

Adult↗
PubMed2001

Overexpressed cell surface interleukin-4 receptor molecules can be successfully targeted for antitumor cytotoxin therapy.

A variety of human solid cancer cell lines and primary cell cultures has been reported to overexpress high-affinity receptors (R) for interleukin-4 (IL-4), a pleiotropic immunoregulatory cytokine. The significance of IL-4R expression is not known; however, IL-4 is able to upregulate adhesion molecules, inhibit cell proliferation, and mediate signal transduction in tumor cell lines. To target IL-4R, we produced a chimeric protein composed of a circular permuted IL-4 and a mutated form of Pseudomonas exotoxin [termed IL4(38-37)-PE38KDEL or cpIL4-PE]. The recombinant cpIL4-PE was highly cytotoxic to cancer cells, but not toxic to normal B cells, T cells, monocytes, and CD34+, even though these cells express detectable numbers of IL-4R. The cytotoxicity was specific because excess of recombinant IL-4 neutralized the cpIL4-PE effect. To further develop this molecule, in vivo antitumor activity was tested in animal models of human cancer. This agent showed remarkable antitumor activity in AIDS-Kaposi's sarcoma, glioblastoma multiforme, and breast cancer models in immunodeficient animals. cpIL4-PE caused partial or complete regression of established human tumors. Preclinical efficacy and toxicity studies provided a therapeutic window in which this cancer-targeted agent could be used. On the basis of these studies, we initiated a Phase I clinical trial for the treatment of recurrent glioblastoma multiforme. Our preliminary clinical results suggest that cpIL4-PE has antitumor activity against the deadliest form of brain tumors, without detectable toxicity to normal brain tissues. Thus, IL-4 receptors represent novel targets for cancer cytotoxin therapy.

Animals↗
PubMed2001

Different lengths of a polymorphic repeat sequence in the thymidylate synthase gene affect translational efficiency but not its gene expression.

PURPOSE: Thymidylate synthase (TS) is a target enzyme of 5-fluorouracil. Recently, the TS gene has been shown to contain a polymorphic tandem repeat sequence. The aim of this study was to determine whether differences in the number of tandem repeats could affect gene expression or mRNA translation. EXPERIMENTAL DESIGN: We quantified TS mRNA isolated from 130 colorectal cancer tissues by real-time reverse transcription-PCR and TS protein in 92 available samples by the fluoro-dUMP binding assay. These values were compared with TS genotypes of the samples determined by a PCR assay. RESULTS: There was no relation between TS genotype and mRNA expression level. On the other hand, cancer tissues with the 3R/3R genotype had a significantly higher TS protein expression level than did those with the 2R/3R genotype. These results suggest that the efficiency of TS mRNA translation is responsible for the genotype-dependent difference in TS protein expression. Further analysis using TS 5'-untranslated region-luciferase reporter constructs showed that the RNA with the three-repeat sequence was translated three to four times more efficiently than that with two-repeat sequence. CONCLUSIONS: From the results of both in vitro and in vivo study, we conclude that TS mRNA with a three-repeat sequence has greater translation efficiency than that with the two-repeat sequence. The results provide the rationale for comprehensive usage of TS genotyping with quantitation of TS mRNA or TS protein to predict the patient's response to 5-fluorouracil-based chemotherapy.

5' Untranslated Regions↗
PubMed2001

[Angioimmunoblastic T-cell lymphoma with hyperplastic germinal centers].

We report a case of angioimmunoblastic T-cell lymphoma (AITL) in a 48-year-old Japanese male. Characteristic clinical manifestations of AITL such as fever, weight loss, skin rash, general lymphadenopathy, Coombs test positivity, and polyclonal hypergammaglobulinemia were present. Histopathologically, the nodal architecture was preserved and germinal centers were, if anything, hyperplastic, which was unusual for AITL. Diagnostic clear cells were absent. Intrafollicular tingible-body macrophages were markedly increased. In the interfollicular zone, proliferation of UCHL-1 + immunoblasts was evident, and high-endothelial postcapillary venule-type vessels were increased. The T-cell receptor gene (C beta 1) was clonally rearranged. Based on these findings, a diagnosis of AITL with hyperplastic germinal centers was made. Six courses of CHOP were administered and no signs of relapse were noticed about two years after diagnosis.

Diagnosis, Differential↗
PubMed2000

A potent, long-acting, orally active (2R)-2-[(1R)-3, 3-difluorocyclopentyl]-2-hydroxy-2-phenylacetamide: novel muscarinic M(3) receptor antagonist with high selectivity for M(3) over M(2) receptors.

A novel series of (2R)-2-[(1R)-3, 3-difluorocyclopentyl]-2-hydroxy-2-phenylacetamides was designed and synthesized based on the structure and biological profiles of an active metabolite 2 of our prototype muscarinic M(3) receptor selective antagonist 1, to develop a potent, long-acting, orally active M(3) antagonist for the treatment of urinary tract disorders, irritable bowel syndrome, and respiratory disorders. Investigation of (2R)-2-[(1R)-3, 3-difluorocyclopentyl]-2-hydroxy-2-phenylacetamides containing a phenyl or heterocyclic ring as the piperidinyl side chain in place of the 4-methyl-3-pentenyl moiety of 15a revealed that this acid moiety was a versatile template for improving the selectivity for M(3) over M(2) receptors in comparison with the corresponding cyclopentylphenylacetic acid group. However, since the in vitro metabolic stability of these analogues was insufficient compared with that of 2, further derivatization was performed by introducing an appropriate hydrophilic group into the phenyl or 2-pyridyl ring. Thus, the 1-(6-aminopyridin-2-ylmethyl)piperidine analogue 15y exhibiting 190-fold selectivity for M(3) receptors (K(i) = 2.8 nM) over M(2) receptors (K(i) = 530 nM) in a human binding assay and good in vitro metabolic stability in dog and human hepatic microsomes was identified. This compound has excellent oral activity at 4 h after oral dosing (1 mg/kg), inhibiting methacholine-induced bronchoconstriction in dogs, and may be useful in clinical situations in which M(3) over M(2) selectivity is desirable.

Acetamides↗
PubMed2000

Thymic epithelial cells responsible for impaired generation of NK-T thymocytes in Alymphoplasia mutant mice.

We have previously shown that the generation of an NK1.1+TCRalphabeta+ (NK-T) cell population is severely impaired in an alymphoplasia mutant (aly/aly) mouse strain and the defect resides in the thymic environment. In the present study, to elucidate the thymic stromal component(s) that affects the development of NK-T cells, radiation bone marrow chimeras were established with the aly/aly mouse as a donor and either the beta2 microglobulin knockout (beta2m-/-) or the CD1d1-/- mouse that also lacks the NK-T cell population as a recipient. A normal population of NK-T cells with a typical NK-T phenotype and functions was detected in both the thymus and the spleen of these chimeras. These findings indicated that a radiation-resistant CD1(-) component of the thymus supported generation of functional NK-T cells from aly/aly precursors. Furthermore, transfer of an intact medullary thymic epithelial cell line into aly/aly thymus significantly induced the generation of NK-T cells in the thymus. These findings suggest that CD1 molecules of bone marrow-derived cells and the medullary epithelial cells acted in concert in the generation of the NK-T cell population and that a function(s) of the medullary thymic epithelial cells other than direct presentation of CD1 molecules to the NK-T precursors is indispensable for the development of NK-T cells.

Animals↗
PubMed2000

Epstein-Barr virus (EBV) load and cytokine gene expression in activated T cells of chronic active EBV infection.

To identify the role of T cells in chronic active Epstein-Barr virus (EBV) infection, EBV and cytokine gene expression was quantified by use of real-time polymerase chain reaction (PCR) among 6 patients who fulfilled the diagnostic criteria for chronic active EBV infection. Four of these patients showed clonal expansion of EBV-infected T cells. Quantitative PCR for EBV DNA in peripheral blood of patients with symptomatic chronic active EBV infection showed higher copy numbers of virus (mean, 1.45 x 10(5) copies/mL) than were seen in blood from patients with infectious mononucleosis (3.08 x 10(3) copies/mL) or with EBV-associated hemophagocytosis (2.95 x 10(4) copies/mL). Fractionated CD3(+) HLA-DR(+) cells from patients with chronic active EBV infection contained higher copy numbers than did CD3(+) HLA-DR(-) cells. Quantitative PCR for cytokines revealed that interferon-gamma, interleukin (IL)-2, IL-10, and transforming growth factor-beta genes were expressed at higher levels in HLA-DR(+) than in HLA-DR(-) T cells. These results suggest that activated T cells in chronic active EBV infection expressed high levels of EBV DNA and both Th1 and Th2 cytokines. EBV-infected T cells may contribute to the unbalanced cytokine profiles of chronic mononucleosis.

Adolescent↗
PubMed2000

Hypermethylated APC DNA in plasma and prognosis of patients with esophageal adenocarcinoma.

BACKGROUND: The adenomatous polyposis coli (APC) locus on chromosome 5q21-22 shows frequent loss of heterozygosity (LOH) in esophageal carcinomas. However, the prevalence of truncating mutations in the APC gene in esophageal carcinomas is low. Because hypermethylation of promoter regions is known to affect several other tumor suppressor genes, we investigated whether the APC promoter region is hypermethylated in esophageal cancer patients and whether this abnormality could serve as a prognostic plasma biomarker. METHODS: We assayed DNA from tumor tissue and matched plasma from esophageal cancer patients for hypermethylation of the promoter region of the APC gene. We used the maximal chi-square statistic to identify a discriminatory cutoff value for hypermethylated APC DNA levels in plasma and used bootstrap-like simulations to determine the P: value to test for the strength of this association. This cutoff value was used to generate Kaplan-Meier survival curves. All P values were based on two-sided tests. RESULTS: Hypermethylation of the promoter region of the APC gene occurred in abnormal esophageal tissue in 48 (92%) of 52 patients with esophageal adenocarcinoma, in 16 (50%) of 32 patients with esophageal squamous cell carcinoma, and in 17 (39.5%) of 43 patients with Barrett's metaplasia but not in matching normal esophageal tissues. Hypermethylated APC DNA was observed in the plasma of 13 (25%) of 52 adenocarcinoma patients and in two (6.3%) of 32 squamous carcinoma patients. High plasma levels of methylated APC DNA were statistically significantly associated with reduced patient survival (P =.016). CONCLUSION: The APC promoter region was hypermethylated in tumors of the majority of patients with primary esophageal adenocarcinomas. Levels of hypermethylated APC gene DNA in the plasma may be a useful biomarker of biologically aggressive disease in esophageal adenocarcinoma patients and should be evaluated as a potential biomarker in additional tumor types.

Adenocarcinoma↗
PubMed2000

Identification of a functional transposase of the Tol2 element, an Ac-like element from the Japanese medaka fish, and its transposition in the zebrafish germ lineage.

The Tol2 element of the medaka fish Oryzias latipes belongs to the hAT family of transposons (hobo/Ac/Tam3). We report here identification of a functional transposase of Tol2 that is capable of catalyzing its transposition in the germ line of zebrafish Danio rerio. A transcript produced from Tol2 encodes a putative transposase. Zebrafish fertilized eggs were coinjected with mRNA transcribed in vitro, using cDNA of the Tol2 transcript as a template and a plasmid DNA harboring a mutant Tol2, which had a deletion in the putative transposase gene but retained necessary cis sequences. The injected fish were raised to adulthood and mated to noninjected fish, and genomic DNA of the progeny fish were analyzed by PCR and Southern hybridization. Half of F(1) fish obtained from one of eight injected fish contained the Tol2 DNA in their genomes but not the vector portion. Among these F(1) fish, Tol2 insertions at four different loci were identified, and some F(1) fish carried two or three different Tol2 insertions, indicating that the germ line of the founder fish is highly mosaic. Sequencing analyses revealed that, in all cases, Tol2 was surrounded by zebrafish genomic sequences, and an 8-bp duplication was created at the target site, indicating that Tol2 was integrated in the zebrafish genome through transposition. This study identifies an autonomous member of a DNA-based transposable element from a vertebrate genome. The Tol2 transposon system should thus be used to develop novel transgenesis and insertional mutagenesis methods in zebrafish and possibly in other fishes.

Animals↗
PubMed2000

Sensitization of cancer cells to interleukin 13-pseudomonas exotoxin-induced cell death by gene transfer of interleukin 13 receptor alpha chain.

We have demonstrated that primary interleukin 13 (IL-13) binding protein IL-13 receptor (IL-13R) alpha chain plays an important role in IL-13 binding and internalization in the IL-13R system. Although IL-13R alpha chain is expressed on many cancer cell lines, some cancer types do not express or express low levels of this receptor chain. Consequently, these cells show no or low sensitivity to the cytotoxic effect of a recombinant chimeric protein composed of IL-13 and a mutated form of a Pseudomonas exotoxin, IL13-PE38QQR. Here we demonstrate that pancreatic cancer, renal cell carcinoma, head and neck cancer, and glioblastoma cell lines that were genetically altered to express high levels of IL-13R alpha chain increase their binding affinity for IL-13, and increase their sensitivity to IL13-PE38QQR by at least 6-fold to 1000-fold compared with mock-transfected control cells. This observation was made by protein synthesis inhibition assay and confirmed by clonogenic assay. Our studies provide a proof of principle for a novel strategy for cancer therapy that combines gene transfer and targeted cytotoxin therapy.

ADP Ribose Transferases↗
PubMed2000

IL-18 contributes to host resistance against infection with Cryptococcus neoformans in mice with defective IL-12 synthesis through induction of IFN-gamma production by NK cells.

The aim of this study was to examine the contribution of IL-18 in host defense against infection caused by Cryptococcus neoformans in mice with defective IL-12 production. Experiments were conducted in mice with a targeted disruption of the gene for IL-12p40 subunit (IL-12p40-/- mice). In these mice, host resistance was impaired, as shown by increased number of organisms in both lungs and brains, compared with control mice. Serum IFN-gamma was still detected in these mice at a considerable level (20-30% of that in control mice). The host resistance was moderately impaired in IL-12p40-/- mice compared with IFN-gamma-/- mice. Neutralizing anti-IFN-gamma mAb further increased the lung burdens of organisms. In addition, treatment with neutralizing anti-IL-18 Ab almost completely abrogated the production of IFN-gamma and also impaired the host resistance. Host resistance in IL-12p40-/- IL-18-/- mice was more profoundly impaired than in IL-12p40-/- mice. Administration of IL-12 as well as IL-18 increased the serum levels of IFN-gamma and significantly restored the reduced host resistance. Spleen cells obtained from infected IL-12p40-/- mice did not produce any IFN-gamma upon restimulation with the same organisms, while those from infected and IL-12-treated mice produced IFN-gamma. In contrast, IL-18 did not show such effect. Finally, depletion of NK cells by anti-asialo GM1 Ab mostly abrogated the residual production of IFN-gamma in IL-12p40-/- mice. Our results indicate that IL-18 contributes to host resistance to cryptococcal infection through the induction of IFN-gamma production by NK cells, but not through the development of Th1 cells, under the condition in which IL-12 synthesis is deficient.

Adjuvants, Immunologic↗
PubMed2000

Structure, function, and targeting of interleukin 4 receptors on human head and neck cancer cells.

Despite advances in diagnosis and treatment, survival rates for patients with head and neck cancer have remained unchanged for the last 30 years. In an attempt to develop novel therapeutic agents, we have observed that a variety of murine and human carcinoma cells expresses high levels of receptors for interleukin 4 (IL-4) in vitro and in vivo. Here, we demonstrate that 17 head and neck cancer cell lines also express surface IL-4 receptors (IL-4R) and IL-4 binds to IL-4R on one cell line studied with low affinity ((k)d = 37.9 +/- 0.4 nM). The investigation of the subunit structure of IL-4R demonstrated that head and neck cancer cell lines expressed mRNA for IL-4R beta chain (also known as IL-4R alpha) and IL-13R alpha' chain (also known as IL-13R alpha1). However, no cell line expressed IL-2R common gamma-chain, which is known to be shared with IL-4R in immune cells. IL-4R is functional because IL-4 strongly induced activation of signal transducers and activators of transcription 6 (STAT-6) in these cell lines. A fusion protein, IL4(38-37)-PE38KDEL, containing translocation and enzymatic domains of Pseudomonas exotoxin and a circularly permuted human IL-4 was found to be highly and specifically cytotoxic to IL-4R-positive head and neck cancer cells, as determined by protein synthesis inhibition assay and confirmed by clonogenic assay. IL4(38-37)-PE38KDEL induced DNA fragmentation and condensation of nuclei indicative of apoptotic cell death. These results establish uniform expression of IL-4R on head and neck cancer cell lines and IL-4 toxin IL4(38-37)-PE38KDEL as a novel therapeutic agent for the possible treatment of human head and neck cancers.

Apoptosis↗
PubMed2000

Reduced host resistance and Th1 response to Cryptococcus neoformans in interleukin-18 deficient mice.

Using interleukin (IL)-18 deficient (IL-18(-/-)) mice, we examined the role of IL-18 in the host resistance and Th1 response against infection with Cryptococcus neoformans. Fungal clearance in the lung was reduced in IL-18(-/-) mice, although there was no significant change in the level of dissemination to the brain. The DTH response, as determined by footpad swelling, was also diminished in IL-18(-/-) mice compared to control wild-type (WT) mice. The levels of IL-12 and interferon (IFN)-gamma in the sera were significantly lower in IL-18(-/-) mice than in WT mice. Spleen cells from infected WT mice produced a high level of IFN-gamma upon stimulation with the microbe, while only a low level of IFN-gamma production was detected in spleen cells from infected IL-18(-/-) mice. Administration of IL-18 almost completely restored the reduced response in IL-18(-/-) mice, while IL-12 showed a marginal effect. These results demonstrated the important role of IL-18 in the resistance and Th1 response of mice to C. neoformans by potentiating the production of IFN-gamma.

Animals↗
PubMed2000

Proviral insertions in the zebrafish hagoromo gene, encoding an F-box/WD40-repeat protein, cause stripe pattern anomalies.

The zebrafish, Danio rerio, has three types of pigment cells (melanophores, xanthophores and iridophores) and, in adult fish, these cells are organized into a stripe pattern. The mechanisms underlying formation of the stripe pattern are largely unknown. We report here the identification and characterization of a novel dominant zebrafish mutation, hagoromo (hag), which was generated by insertional mutagenesis using a pseudotyped retrovirus. The hag mutation caused disorganized stripe patterns. Two hag mutant alleles were isolated independently and proviruses were located within the fifth intron of a novel gene, which we named hag, encoding an F-box/WD40-repeat protein. The hag gene was mapped to linkage group (LG)13, close to fgf8 and pax2.1. Amino acid sequence similarity, conserved exon-intron boundaries and conserved synteny indicated that zebrafish hag is an ortholog of mouse Dactylin, the gene mutated in the Dactylaplasia (Dac) mouse [1]. The Dac mutation is dominant and causes defects in digit formation in fore- and hindlimbs. This study revealed that the hag locus is important for pattern formation in fish but is involved in distinct morphogenetic events in different vertebrates.

Amino Acid Sequence↗