Biomedical subjects
Publications and source records attributed to Y Shibata.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
The Chernobyl nuclear power plant accident happened on April 26, 1986. We investigated the cause of the striking increase in frequency of thyroid cancer in children who lived within a 150 km radius of Chernobyl and who were born before and after the accident. No thyroid cancer was seen in 9472 children born in 1987-89, whereas one and 31 thyroid cancers were recorded in 2409 children born April 27, 1986, to Dec 31, 1986, and 9720 born Jan 1, 1983, to April 26, 1986, respectively. Short-lived radioactive fallout caused by the Chernobyl accident probably induced thyroid cancer in children living near Chernobyl.
Macrophage colony-stimulating factor (M-CSF) is one of several hematologic growth factors capable of regulating the survival, proliferation, and differentiation of macrophages, but its role in modulation of the accumulation and function of alveolar macrophages (AMs) in vivo is not well defined. Osteopetrotic (Op/Op) mice have no detectable M-CSF and show variable tissue-specific reductions in macrophage numbers. It was hypothesized that AMs would be decreased in number and have altered function in Op/Op mice because of the absence of M-CSF. Lung macrophages identified by Mac-3 staining in lung sections were decreased in number in 20-day-old Op/Op mice (P <.001) but not Op/Op mice older than 4 months (P =.68) compared with findings in age-matched littermate controls. The numbers of AMs recovered by bronchoalveolar lavage (BAL) were also reduced in young but not adult Op/Op mice compared with controls. Expression of interleukin-3 (IL-3) was increased in the lungs of Op/Op mice compared with controls as determined by quantification of IL-3 cytokine levels (P =.04), bioactivity (P =.02), and messenger RNA transcript levels. AMs of Op/Op mice spontaneously released higher levels of matrix metalloproteinases (MMPs) than AMs of controls as determined by immunohistochemical staining of AMs and zymographic assessment of BAL fluid and AM lysates. Consistent with an increased release of MMP, Op/Op mice had abnormal elastin deposition and spontaneously developed emphysema in the absence of molecular or cellular evidence of lung inflammation. These data show that the AM deficiency observed in young Op/Op mice is spontaneously corrected with age and is associated with increased lung levels of IL-3, spontaneous MMP expression by AMs, and destruction of lung tissue.
Dendritic cells (DCs) are essential antigen-presenting cells with a wide variety of functions relating to both adaptive and innate immunity. Recently, interactions of DCs with natural killer (NK) cells and NK1.1-positive T cells have been reported in mice. However, in humans, this interaction is not well understood. Here we report the use of a coculture method to analyze the modulation of NK cell function in antitumor immunity by DCs. We found that peripheral blood DCs (PDCs) enhanced NK cell activity in cytotoxicity assay, even without direct contact between DC and NK cells. In contrast, neither monocyte-derived DCs (MoDCs), nor TNF-alpha-treated MoDCs, stimulated NK lytic activity. Secretion of IL-12 and TNF-alpha into the PDC-NK coculture supernatant was increased. However, blocking antibodies against these cytokines could not completely abolish the upregulation of NK activity, suggesting the presence of other soluble factor(s) that affect DC-NK cell interaction. To summarize, this study demonstrates for the first time the direct activation of human NK cells by DC-NK cell interaction in vitro, suggesting that DCs may have a central role linking the innate and adaptive immune responses. Moreover, in stimulating NK cell function, PDCs appear to have a different potential from MoDCs.
T2Rs comprise a G-protein-coupled receptor superfamily that contains functionally defined bitter taste receptors. Here we report the tissue expressions and coding single-nucleotide polymorphisms (cSNPs) in human T2R genes (hT2R3, hT2R4, and hT2R5) on chromosome 7q31. We first demonstrated that hT2R3, hT2R4, and hT2R5 are actually expressed in the circumvallate papillae of the human tongue by reverse transcription-polymerase chain reaction (RT-PCR). We identified six cSNPs within the T2R receptor genes. The hT2R4 and hT2R5 contained four and one cSNPs that cause missense mutations, respectively, while hT2R3 included one silent nucleotide mutation. However, we could not find any nonsense mutations that resulted in a frameshift or a premature stop codon within the open reading frames. Genotype frequencies of each cSNP were in Hardy-Weinberg equilibrium. The identification of nucleotide diversity and amino acid polymorphisms in human T2R receptors could help clarify individual differences in the acceptability and sensitivity to bitter compounds.
We report a novel aqueous derivatization of selenomethionine (Semet), selenoethionine (Seet) and trimethylselenonium ion (TmSe) by NaBH4 and HCI to volatile selenium species, namely, diethyldiselenide (DeDSe), dimethyldiselenide (DMDSe), dimethylselenide (DmSe) and ethylhydrogenselenide (ESeH), in the hydride generation (HG) system. The volatile selenium compounds produced in the HG system were on-line trapped and concentrated in a U-tube that was immersed in the liquid nitrogen trap. The trapped volatile Se compounds were volatilized at 80 degrees C in a water bath, and 50-500 microL of volatile gas was injected into the GC/AED and GC/MS, respectively. It has been established that DmSe, DmDSe, and DeDSe are the predominant Se compounds that are produced in the HG system from TmSe, Semet, and Seet, respectively, followed by ESeH from Seet. Analytical methods previously employed have stated that these compounds are inactive in the HG system. Prior decomposition of Semet, Seet, and TmSe to selenous acid is essential before HG. To the best of our knowledge, current findings for the production and identification of volatile selenium compounds in the HG system are new and different from existing reports; hence, direct estimation of Semet, Seet, and TmSe is possible when coupling with a HG system using a suitable Se-specific detector.
We examined the simultaneous uptake of porphyrin and (LDL) by four established cell lines of glioma and normal fibroblasts using flow cytometry (FCM). The results indicated porphyrin and LDL showed competitive conjugation with the LDL receptor. These results support the theory of the porphyrin uptake via the LDL receptor.
A unique lymphocyte lineage, the Valpha14 NKT cells, expresses both NK1.1 and an invariant antigen receptor encoded by Valpha14 and Jalpha281 gene segments. Valpha14 NKT cells play crucial roles in various immune responses, including autoimmune diseases, allergic reactions and anti-tumor immunity. Valpha14 NKT cells were demonstrated to be essential for anti-tumor effect of IL-12 in vivo. Here, we report that adoptive transfer of IL-12-activated Valpha14 NKT cells prevents hepatic metastasis of B16 melanoma. The injection of large amounts of IL-2, IL-4, and IFN-gamma, which are cytokines produced by activated Valpha14 NKT cells, exhibited no significant inhibition of the metastasis of this melanoma. The cells prepared from the liver of IL-12-injected mice expressed a potent cytotoxic activity on B16 melanoma cells in vitro. Although the adoptive transfer of IL-12-activated Valpha14 NKT cells prevents hepatic metastasis of B16 melanoma, activated NK cells from IL-12-injected RAG-1-/- mice failed to inhibit the metastasis of this melanoma. Thus, the anti-tumor effect of IL-12 can be replaced by adoptive transfer of IL-12-activated Valpha14 NKT cells but not by IL-12-activated NK cells, suggesting a minor role of NK cells for the IL-12-mediated anti-tumor effect in this experimental system. Moreover, our studies have suggested the involvement of direct cytotoxic mechanisms rather than cytokine-mediated immune responses at the effector phase of the Valpha14 NKT cell-mediated anti-tumor activity.
The RIKEN Mouse Gene Encyclopaedia Project, a systematic approach to determining the full coding potential of the mouse genome, involves collection and sequencing of full-length complementary DNAs and physical mapping of the corresponding genes to the mouse genome. We organized an international functional annotation meeting (FANTOM) to annotate the first 21,076 cDNAs to be analysed in this project. Here we describe the first RIKEN clone collection, which is one of the largest described for any organism. Analysis of these cDNAs extends known gene families and identifies new ones.
Dopaminergic neurons of the mouse mesencephalon originate in the ventricular zone and migrate radially along radial glia then tangentially along nerve fibers that express the neural cell adhesion molecule L1 to form the substantia nigra (A9 group) and ventral tegmental area (VTA) (A10 group). The role of L1 in migration of dopaminergic neuronal precursors was investigated in L1 knockout mice by tyrosine hydroxylase (TH) immunostaining. An altered rostrocaudal distribution of dopaminergic neurons was observed within the substantia nigra and VTA of L1-minus mice. In L1-minus mice at postnatal day 0, TH-positive cells were present abnormally in the dorsomedial mesencephalon, suggesting impaired migration. Axons projecting from the substantia nigra to the caudate putamen also exhibited an abnormal targeting pattern. There was no evidence of dopaminergic cell loss in the mutant SN. Abnormal localization of dopaminergic neurons in L1-minus mice was also evident in the zona incerta of the thalamus (A13 group), and the arcuate (A12) and periventricular nucleus (A14) of the hypothalamus. Cell bodies and axons in the substantia nigra, VTA, and hypothalamus of wild type mouse embryos expressed L1. These results suggested that L1 plays an important developmental role in the organization of dopaminergic neuronal cell groups in the mesencephalon and diencephalon.
This paper describes an improved electroosmotic elution system for preparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) based on the epochal idea of H. V. Tan et al. (Nucleic Acids Res. 1988, 16, 1921-1930). In this elution system, a semipermeable membrane, mounted under the gel terminal end, works as the elution pump as well as the partition of the elution chamber. We refer to this system as the "electroosmotic medium pump system." Operation of the constructed apparatus (3.6 cm i.d. disk gel column) and resolution of the protein bands were examined by separation of the model protein mixture (bovine serum albumin (BSA), ovalbumin, bovine carbonic anhydrase, soybean trypsin inhibitor) and purification of the membrane protein, dipeptidyl peptidase IV (DPP IV). The Spectra/Por 7 dialysis membrane provided a better flow profile for the elution buffer. The four model proteins of the protein mixture were able to be completely separated from each other and recovered without dilution. The maximum protein concentration of eluate achieved was 93 mg/ml, when applying a single component, BSA fraction V, as a sample. Furthermore, the multifunctional ectoenzyme, DPP IV, was purified in a single step.
The Japanese cedar pollen (JCP) is a major allergen with respect to pollinosis in Japan. It is believed that interleukin-4 (IL-4) and interleukin-5 (IL-5) derived from lymphocytes and other cells play a pivotal role in allergic reactions. We investigated whether the JCP antigen stimulates the release of these cytokines by peripheral blood mononuclear cells (PBMCs). PBMCs from eight adults (five adults with JCP pollinosis and three adults without JCP pollinosis) were co-incubated with purified JCP antigens. IL-4 was released in response to JCP antigens in six of the eight subjects at 24 h and in three subjects at 48 h. IL-4 release at 24 h occurred in all five subjects with JCP pollinosis but in only one of the three subjects without pollinosis. IL-5 was released in response to the JCP antigen in five of the eight subjects at 24 h and 48 h, including four of the five subjects with JCP pollinosis and one of the three subjects without pollinosis. These results suggest that PBMCs were more likely to release IL-4 and IL-5 in the presence of JCP pollinosis.
We have developed a new class of cloning vectors: lambda-full-length cDNA (lambda-FLC) cloning vectors. These vectors can be bulk-excised for preparing full-length cDNA libraries in which a high proportion of the plasmids carry large inserts that can be transferred into other (for example, functional) vectors. Unlike other cloning vectors, lambda-FLC vectors accommodate a broad range of sizes of eukaryotic cDNA inserts because they contain "size balancers." Further, the main protocol we use for direct bulk excision of plasmids is mediated by a Cre-lox system and is apparently free of size bias. The average size of the inserts from excised plasmid cDNA libraries was 2.9 kb for standard and 6.9 kb for size-selected cDNA. The average insert size of the full-length cDNA libraries was correlated to the rate of new gene discovery, suggesting that effectively cloning rarely expressed mRNAs requires vectors that can accommodate large inserts from a variety of sources. Part of the vectors are also suitable for bulk transfer of inserts into various functional vectors.
Many types of infections associated with colorectal cancer have been reported. Here, we describe a rare case of thoracic empyema that was observed during immunotherapy for recurrent colon cancer. Culture of the pleural fluid yielded Streptococcus bovis, which is known to be associated with gastrointestinal lesions, especially colorectal malignancies. The possible correlation between these two clinical entities-empyema and colon cancer-is discussed.
Two patients developed chondrolysis following injection of 0.4% aqueous gentian violet into the glenohumeral joint to visualize a rotator cuff tear during surgery. In both cases, conventional radiographs revealed joint space narrowing 10-12 months after surgery. Histological examination of the humeral heads revealed loss of the articular cartilage.
We examined the expression pattern of two major gap junction proteins, connexin 26 (Cx26) and connexin 32 (Cx32), in rat mammary glands during pregnancy and lactation. Immunohistochemically the two different Cxs were coexpressed in acinar cells and were independently modulated according to the physiological cell activity. Western blot analysis demonstrated that Cx26 gradually increased from early pregnancy, while Cx32 rapidly and dramatically increased at 16 h after parturition, and that both Cxs reached a maximum early in lactation. Increased expression of both Cxs was confirmed by Northern blot analysis showing that their mRNA transcripts were significantly induced on the day of parturition. We also analyzed double-immunofluorescent staining for Cx26 and Cx32 on a confocal laser scanning microscope, in order to examine colocalization of these Cxs in situ. Cx26 immunoreactivity mostly overlapped with Cx32-positive sites in acinar cells of lactating mammary glands, indicating that both Cxs were colocalized together in the same gap junctional plaques in lactation. These results suggest that upregulation of Cx26 and Cx32 in acinar cells at lactating stages, with colocalization in the same gap junctional plaques, may be important for control of secretion by acinar cells in rat mammary glands.
A case of solitary thyroid metastasis of renal clear cell carcinoma is described. The patient was a 77-year-old Japanese woman, who was referred to our department after a thyroid tumor was identified in May 1999. She had a history of renal clear cell carcinoma of the left kidney, which had been partially resected 3 years previously. Ultrasound sonography demonstrated that a well-demarcated hypoechoic mass containing high-echo spots representing small calcifications, which measured 45 x 34 x 31 mm in size, occupied the left lobe. Computed tomography revealed a low-density mass containing small calcifications. The results of preoperative fine-needle aspiration cytology strongly suggested a clear cell carcinoma metastasizing to the thyroid. A left hemithyroidectomy was performed on July 27, 1999. A histological examination revealed that the neoplasm was composed of tumor cells with abundant clear cytoplasm and round nuclei. The histological characteristics of this thyroid tumor were virtually identical to the renal cell carcinoma resected 3 years previously. Thyroglobulin stained negatively in the clear cells of the resected thyroid tumor in an immunohistochemical analysis. Clinically, the thyroid gland is a rare site of tumor metastasis; however, we should also consider the possibility of metastasis in the case of thyroid tumor patients with a history of renal cell carcinoma.