Biomedical subjects

Y Hayakawa

Publications and source records attributed to Y Hayakawa.

At least 19 recordsLinked to original sources

PubMed2000

Plasmatocyte spreading peptide (PSP1) and growth blocking peptide (GBP) are multifunctional homologs.

Recently, we identified Plasmatocyte spreading peptide (PSP1) from the moth Pseudoplusia includens and reported that it mediates adhesion of hemocytes to foreign surfaces. PSP1 is structurally very similar to three classes of peptides identified earlier from other species of Lepidoptera: growth blocking peptide (GBP) originally identified in Pseudaletia separata, and a series of related peptides from other species designated as paralytic (PP) or cardioactive (CAP) peptides. In this study, we conducted parallel experiments in P. includens and P. separata to determine whether PSP1 and GBP have distinct or multiple biological activities. Both peptides affected the adhesive state of hemocytes from each moth very similarly. PSP1 and GBP exhibited significant growth blocking and paralytic activity in P. separata. Both peptides also had growth blocking activity in P. includens although larvae had to be injected with higher doses of each peptide to reduce weight gain than was observed for P. separata. However, GBP and PSP1 had little paralytic activity in P. includens. Collectively, our results indicate that GBP and PSP1 are multifunctional, but that some interspecific variation also exists in their growth blocking and paralytic activities. We suggest that all PSP1, GBP, PP and CAP family members are homologs that likely have multiple biological activities. Based upon the unique consensus sequence of their N termini, we propose that these molecules be henceforth referred to as members of the "ENF" peptide family.

Journal Article↗

PubMed2000

Antibody response to toxic shock syndrome toxin-1 of Staphylococcus aureus in dairy cows.

Antibody response to toxic shock syndrome toxin-1 (TSST-1) of Staphylococcus aureus in dairy cows was examined by enzyme linked immunosorbent assay (ELISA). Serum antibody to TSST-1 was not detected in 39 (76.5%) of 51 calves, which were 1-6 months of age. In contrast, TSST-1 antibody was demonstrated in 1728 (72.6%) of 2380 lactating cows housed on 36 dairy farms. The ELISA values of antibody ranged from 0.2 to 3.0 OD and presented a distribution with the peak at 1.6 OD. The mean ELISA value differed between farms, and it increased slightly along with parturient history. Somatic cell counts of milk from 174 lactating cows was compared with TSST-1 antibody and tst1,000,000 cells per ml. The mean ELISA values in milk were lower than those of sera, but they rose as somatic cells increased. The tst gene of S. aureus detected in 76.0-86.2% of the milk samples containing somatic cells > 500,000 cells per ml, a level which indicates mastitis. The data suggests that many lactating cows may be infected by TSST-1- producing S. aureus.

Animals↗

PubMed2000

CD27-mediated activation of murine NK cells.

CD27, a member of the TNF receptor superfamily, has been implicated in T cell activation, T cell development, and T cell-dependent Ab production by B cells. In the present study we examined the expression and function of CD27 on murine NK cells. Murine NK cells constitutively expressed CD27 on their surface. Stimulation with immobilized anti-CD27 mAb or murine CD27 ligand (CD70) transfectans solely could induce proliferation and IFN-gamma production of freshly isolated NK cells and enhanced the proliferation and IFN-gamma production of anti-NK1.1-sutimulated NK cells. Although NK cell cytotoxicity was not triggered by anti-CD27 mAb or against CD70 transfectants, prestimulation via CD27 enhanced the cytotoxic activity of NK cells in an IFN-gamma-dependent manner. These results suggest that CD27-mediated activation may be involved in the NK cell-mediated innate immunity against virus-infected or transformed cells expressing CD70.

Adjuvants, Immunologic↗

PubMed2000

Multi-layer energy filter for realizing conformal irradiation in charged particle therapy.

A new type of filter for charged particle radiotherapy is developed to reduce unwanted dose transfer to the normal tissues around a tumor. The new filter can make a static irradiation field where the width of the spread-out Bragg peak (SOBP) is two-dimensionally adjusted. That makes the field conformal to the tumor three-dimensionally. The filter is made of many layers produced by using stereolithography. The layer has a miniaturized structure that has geometrical similarity to the conventional ridge filter. Shapes of cone and pyramid are also usable for the unit-cell constructing the layer. The spread of the field in the depth direction is decided by the thickness of the filter, or by the number of layers. The experimental result of the irradiation using the ridge-type construction shows a good agreement with an estimate by the Monte Carlo calculation. By combining this technique with intensity modulation that has lateral position dependence, the conformal irradiation can be achieved by a simple procedure.

Equipment Design↗

PubMed2000

Apraxia of single tool Use.

We report a 72-year-old right-handed man who showed an 'apraxia of tool use' after a cerebral infarct in the territory of the left middle cerebral artery. His apraxia of tool use was characterized by a clear dissociation between the inability to use a single tool and the ability to use plural tools. Most of the errors occurred in selecting an appropriate target where a tool is expected to be applied. Detailed examinations confirmed that his conceptual knowledge of tool use was well preserved. Furthermore, when a target of a tool was provided as a cue, he used a single tool correctly. These results suggest that his inability to use a single tool originated from his inability to evoke a target image from an actual tool.

Aged↗

PubMed1999

Synthesis and biological evaluation of 1,1-difluoro-2-(tetrahydro-3-furanyl)ethylphosphonic acids possessing a N9-purinylmethyl functional group at the ring. a new class of inhibitors for purine nucleoside phosphorylases.

1,1-Difluoro-2-(tetrahydro-3-furanyl)ethylphosphonic acids cis-3 and trans-3 possessing a N9-purinylmethyl functionality at the ring were synthesized and tested as "multi-substrate analogue" inhibitors for purine nucleoside phosphorylases. Radical cyclization of allyic alpha,alpha-difluorophosphonate (E)-7 was applied to construct the alpha,alpha-difluorophosphonate-functionalized tetrahydrofuranyl moiety. The IC50 values of cis-3 and trans-3 for human erythrocyte PNP-catalyzed phosphorylation of inosine were determined to be 88 and 320 nM, respectively. The stereochemistry of the inhibitors was found to affect significantly the inhibitory potency.

Antineoplastic Agents↗

PubMed1999

A new boronated porphyrin (STA-BX909) for neutron capture therapy: an in vitro survival assay and in vivo tissue uptake study.

A new boronated porphyrin compound (STA-BX909) was developed as a possible agent for boron neutron capture therapy. The boron concentration was measured by an in vivo rat experimental brain tumor model and an in vitro cell culture study. This agent was compared to sodium borocaptate (BSH) which has been used in clinical trials of boron neutron capture therapy. In the 9L rat brain tumor model, STA-BX909 achieved a higher boron tumor/blood ratio 24 h after injection in comparison to BSH. A boron concentration study in cultured glioma cell lines (U-251, U-87, 9L) demonstrated an increased boron concentration as a function of exposure time to STA-BX909, while the boron concentration remained stable with increasing exposure time to BSH. Use of a colony forming assay with thermal neutron irradiation revealed more cytotoxicity with STA-BX909 than BSH when the same concentration of 10B was administered. We concluded that STA-BX909 may be an effective drug for use in boron neutron capture therapy and that it merits further investigation.

Animals↗

PubMed1999

Benzimidazolium triflate-activated synthesis of (6-4) photoproduct-containing oligonucleotides and its application.

In the solid-phase synthesis of oligonucleotides containing the pyrimidine(6-4)pyrimidone photoproduct using a dinucleotide building block, considerable amounts of by-products were found as the chain length increased. The by-products were the major product when a 49mer was synthesized on a 40 nmol scale. It was assumed that these by-products were formed by the coupling of phosphoramidites with the N3 imino function of the 5' component of the (6-4) photoproduct. We examined imidazolium triflate and benzimidazolium triflate to find an alternative activator for DNA synthesis. Imidazolium triflate prevented by-product formation to some extent, but the coupling yields were low. Benzimidazolium triflate was comparable to tetrazole in coupling efficiency and reduced by-product formation to a great extent, without modification of the synthesizer program. The obtained 49mer was used to detect proteins that recognize UV-damaged DNA in HeLa cell extracts. Two major protein-DNA complexes were found when a 49mer duplex was used as probe, while a 30mer duplex failed to detect one of them. This application showed the usefulness of long chain 'damaged' oligonucleotides in biochemical studies.

Benzimidazoles↗

PubMed1999

Significance of myocytes with positive DNA in situ nick end-labeling (TUNEL) in hearts with dilated cardiomyopathy: not apoptosis but DNA repair.

BACKGROUND: The presence of apoptotic myocytes has been reported in human hearts with dilated cardiomyopathy (DCM) on the basis of a positive finding of DNA in situ nick end-labeling (TUNEL). However, ultrastructural evidence of myocyte apoptosis has not been obtained. METHODS AND RESULTS: A total of 80 endomyocardial biopsies were obtained from right and left ventricles of 20 patients with DCM and 20 normal control subjects. TUNEL-positive myocytes were found by light microscope in 15% of DCM specimens (controls, 0%, P<0.05), and the percentage of TUNEL-positive myocytes per section in DCM was 1. 0+/-2.7% (mean+/-SD). According to TUNEL at the electron microscopic level (EM-TUNEL), immunogold particles, which label DNA breaks with 3'-OH terminals, were markedly accumulated in the bizarre-shaped nuclei, with widespread clumping of chromatin (so-called "hypertrophied nuclei") of the myocytes obtained from DCM. Their ultrastructure was neither apoptotic nor necrotic but rather that of living cells. Taq polymerase-based DNA in situ ligation assay, which detects double-stranded DNA fragments more specifically than TUNEL, did not detect a positive reaction in any case. In mirror sections, all of the TUNEL-positive myocytes in DCM simultaneously expressed proliferating cell nuclear antigen, which is required for both DNA replication and repair, but Ki-67, a replication-associated antigen, was completely negative in all cases, which appeared to rule out cell proliferation activity. CONCLUSIONS: Most of the TUNEL-positive myocytes in hearts with DCM are not apoptotic but rather living cells with increasing activity of DNA repair.

Apoptosis↗

PubMed1999

Structure of the insect cytokine peptide plasmatocyte-spreading peptide 1 from Pseudoplusia includens.

The structure of the recently identified plasmatocyte spreading peptide from the moth Pseudoplusia includens (PSP1) has been determined by NMR spectroscopy. This novel insect cytokine consists of 23 amino acid residues and a single disulfide bond. Torsion angle dynamics calculations utilizing a total of 337 distance constraints yielded an ensemble of 30 structures with an average backbone root mean square deviation for residues 7-22 of 0.18 A from the mean structure. The structure consists of a disordered N-terminal region and a well defined core that is stabilized by numerous hydrophobic interactions and a short beta-hairpin. Structural comparisons confirm that PSP1 adopts an epidermal growth factor (EGF)-like fold with close similarity to the C-terminal subdomain of EGF-like module 5 of human thrombomodulin. The combination of the three-dimensional structure of PSP1 and the extensive literature on EGF-receptor interactions should accelerate the process of identifying the specific residues responsible for receptor binding activity of this family of immunoregulatory peptides.

Amino Acid Sequence↗

PubMed1999

Solution structure of an insect growth factor, growth-blocking peptide.

Growth-blocking peptide (GBP) is an insect growth factor consisting of 25 amino acid residues that retards the development of lepidopteran larvae at high concentration while it stimulates larval growth at low concentration. In this study, we determined the solution structure of GBP by two-dimensional 1H NMR spectroscopy. The structure contains a short segment of double-stranded beta-sheet involving residues 11-13 and 19-21 and a type-II beta-turn in the loop region (residues 8-11), whereas the N and C termini are disordered. This is the first report of the three-dimensional structure of the peptiderigic insect growth factor, and the structure of the well defined region of GBP was found to share similarity with that of the C-terminal domain of the epidermal growth factor (EGF). Because GBP has been reported to stimulate DNA synthesis of not only insect cells but also human keratinocyte cells at the same level with EGF, the structural similarity between GBP and EGF may lead to the interaction of GBP to EGF receptor.

Amino Acid Sequence↗

PubMed1999

Genomic organization of the genes encoding dihydroflavonol 4-reductase for flower pigmentation in the Japanese and common morning glories.

Genomic DNA segments (approximately 17kb) containing three DFR genes in the Japanese and common morning glories were sequenced. The three DFR genes in both plants were found to be arranged in a tandem array, and all of them comprised six exons with identical intron positions. Their DFR-B genes carrying longer introns than the DFR-A and DFR-C genes were expressed extensively in the young buds of pigmented flowers, and the transcription starting site for the DFR-B mRNA of the Japanese morning glory was determined. The DFR-B gene of the common morning glory was expressed considerably in stems, moderately in sepals and leaves, whereas the DFR-A and DFR-C genes of the same plant were expressed scarcely but significantly in the young flower buds and stems. Several novel mobile element-like sequences of around 200bp were found in the genomic DFR regions. A phylogenetic tree indicated that each DFR gene in the Japanese morning glory is most closely related to the corresponding DFR gene in the common morning glory, and that the DFR-B gene is the most diversified gene among the three DFR genes. These structural and functional features of the DFR genes and their evolutionary implications are discussed.

Alcohol Oxidoreductases↗

PubMed1999

Dopamine and serotonin in the larval CNS of a drosophilid fly, Chymomyza costata: are they involved in the regulation of diapause?

Developmental profiles of dopamine (DA) and serotonin (5-hydroxytryptamine, 5-HT) in the larval CNS of Chymomyza costata were measured by HPLC using electrochemical detection. Larvae of two strains, wild-type (W) and nondiapause mutant (M), were maintained either under long-day (LD, inducing pupariation) or short-day (SD, inducing diapause in W-strain) photoperiods. The levels of DA ranged from 10 fmol/CNS (early 3rd instar larvae) to 60 fmol/CNS (150-day-old diapausing larvae); the range for 5-HT was from 10 fmol/CNS to 75 fmol/CNS in the same larvae. During the 3rd larval instar, which is the decisive stage for photoperiodic induction of diapause, no differences were found in DA developmental profiles between different strains or conditions. Some differences were found in 5-HT developmental profiles, but only after the end of sensitive stage, and were therefore regarded as insignificant for regulation of developmental mode. Similarly, no clear correlations between the developmental profiles of DA and 5-HT and the course of developmental changes during the maintenance and termination of a few-month-long larval diapause were observed. Furthermore, the DA and 5-HT levels in the CNS were pharmacologically manipulated by feeding the larvae with either precursors or enzyme inhibitors of DA and 5-HT biosynthesis. Although retardations of growth and development were observed, the treated larvae retained full capacity for the photoperiodic response, irrespective of the level of DA or 5-HT in their CNS. Larvae with their 5-HT depleted to trace levels survived and were capable of diapause induction, maintenance, and termination. Depletion of DA to trace levels resulted in 100% mortality. Collectively, the present study indicates that 5-HT in the CNS is dispensable for the photoperiodic response in C. costata. More information is needed to elucidate the potential role of DA.

5-Hydroxytryptophan↗

PubMed1999

Perforin-dependent NK cell cytotoxicity is sufficient for anti-metastatic effect of IL-12.

IL-12 exerts a potent anti-tumor effect, which is possibly mediated by multiple mechanisms including activation of NK and NKT cells, induction of cytotoxic T lymphocytes, and inhibition of angiogenesis. In the present study, we characterized the cytotoxic effector cells and mechanisms responsible for the anti-metastatic effect of IL-12. Administration of IL-12 had a comparable inhibitory effect on experimental lung metastasis of B16 melanoma cells in wild-type C57BL/6 mice and RAG-2-/- mice that lack T and NKT cells, which was abolished by depletion of NK cells. Cytotoxic activity of liver and splenic mononuclear cells against B16 was induced by IL-12 administration in RAG-2-/- mice at a level comparable to that in wild-type mice, which was also abolished by depletion of NK cells. Moreover, the anti-metastatic effect of IL-12 was abrogated by perforin deficiency, but not by Fas ligand deficiency, in association with a lack of IL-12-induced cytotoxic activity of liver and splenic mononuclear cells against B16. These results suggest that perforin-dependent cytotoxicity of IL-12-activated NK cells is sufficient for the anti-metastatic effect of IL-12.

Animals↗

PubMed1999

Primary biliary cirrhosis associated with type A gastritis and chronic thyroiditis.

We report a patient with primary biliary cirrhosis (PBC) associated with type A gastritis, chronic thyroiditis, and iron deficiency anemia. The patient was a 45-year-old Japanese woman who was admitted to our hospital with severe microcytic and hypochromic anemia, abnormal results for liver function tests, and a diffuse goiter. The diagnosis of PBC (Scheuer's stage II) was confirmed by the presence of specific anti-mitochondrial antibody in high titers and histological examination showing chronic non-suppurative destructive cholangitis with bridging fibrosis. Additionally, marked atrophic mucosa throughout the body and fundus of the stomach was observed endoscopically, and there was positivity for intrinsic factor antibody, an extremely low ratio of serum pepsinogen A to C, and hypergastrinemia, indicating coexisting type A gastritis. The severe anemia was thought to be caused by failure of dietary iron absorption related to achlorhydria with this gastritis. However, the serum level of vitamin B12 was normal. She also had autoimmune thyroiditis. PBC is frequently associated with extrahepatic autoimmune diseases, including ductular lesions. However, the association of PBC with type A gastritis is quite rare, although the stomach is also an exocrine glandular structure. This particular case, in addition to previous reports, leads to a discussion of whether type A gastritis should be regarded as a possible, although uncommon, component disorder of so-called dry gland syndrome.

Anemia, Iron-Deficiency↗

PubMed1999

An electronic survey of opinions on the compatibility of current X-ray generators with intra-oral digital X-ray systems.

OBJECTIVES: To assess opinions on the compatibility of current X-ray generators with intra-oral digital X-ray systems. METHODS: A questionnaire was posted in both English and in Japanese on oral and maxillofacial radiology electronic bulletin boards. The questionnaire was also mailed to selected researchers and manufacturers in oral and maxillofacial radiology. The replies were evaluated to determine opinion on the current and future status of digital intra-oral imaging with special reference to their compatibility with current X-ray generators. RESULTS: Seventy-one replies were received from 19 countries: 39% from Japan and Korea, 27% from North America, 25% from Europe and 8% from the rest of the world. Eighty per cent of respondents were from academia, 15% from industry and the remainder largely in private practice. Respondents' experience was equally divided between solid state, mainly charge-coupled devices (CCDs) and photostimulable phosphor (IP) technologies. Sixty-eight per cent considered that current X-ray generators are compatible with intra-oral digital systems and many believed this was due to their gray scale flexibility. Twenty-eight per cent believed that existing X-ray generators are inconsistent with low exposure times. Many of the replies suggested that in future pixel size would decrease and bit depth and receptor sensitivity increase. CONCLUSIONS: Most respondents are happy to use existing X-ray generators with digital X-ray systems. However, they also believe that increased sensitivity of receptors could lead to more stringent designs of X-ray generators to ensure more reliable outputs in the low exposure range.

Attitude of Health Personnel↗

PubMed1999

Diagnostic value of endoscopic retrograde pancreatography in chronic pancreatitis based on the new criteria proposed by the Japan Pancreas Society in 1995: comparison with the criteria proposed by the Japanese Society of Gastroenterology in 1983.

This study evaluated the new criteria for the diagnosis of chronic pancreatitis (CP) with endoscopic retrograde pancreatography (ERP) proposed by the Japan Pancreas Society in 1995 by comparing it with the older criteria of the Japanese Society of Gastroenterology proposed in 1983. No significant differences were noted between the two when the diagnostic sensitivity of ERP was considered in calcifying CP. Among 54 patients of noncalcifying CP (group I) with ERP diagnosis of moderate or advanced pancreatitis by the previous criteria, only one of 22 with the localized type was definite CP. The remaining 21 were ruled out as either definite or probable CP, and six were classified as having chronic obstructive pancreatitis based on the new criteria. In contrast, a diagnosis of definite CP was made not only for all the 32 patients with CP (group I) of diffuse type but also in 11 cases of CP (group II) with diffuse minimal pancreatitis showing irregular dilatation of the side branches with scattered distribution throughout the gland. In a series of 15 follow-up patients with CP (group II) having initial ERP diagnosis of minimal pancreatitis, CP group I developed in three of five cases of diffuse minimal pancreatitis, which is consistent with definite CP by the new criteria, whereas progression to this group of CP was found in none of the 10 patients with localized minimal pancreatitis. These results indicate that although localized CP is excluded from CP, the incidence of diffuse noncalcifying CP diagnosed by ERCP was increased with the new criteria, and detecting radiologic features with diffuse irregular dilatation of the branch ducts based on these criteria may lead to early diagnosis of CP.

Calcinosis↗

PubMed1999

Wakame seaweed suppresses the proliferation of 7,12-dimethylbenz(a)-anthracene-induced mammary tumors in rats.

We examined the anti-tumor proliferation effects of wakame seaweed on 7,12-dimethylbenz(a)-anthracene (DMBA)-induced rat mammary tumor. DMBA was administered to 8-week-old female Sprague-Dawley rats, and rats which developed mammary tumors were assigned randomly to three groups. Commercial rat feed was used in a control group (group I-A), and two feed mixtures were prepared, which contained commercial rat feed blended with wakame at 1.0% (group I-B) and 5.0% (group I-C) by weight. The respective feeds were given to each group for 8 weeks, and changes in mammary tumor size were compared. At the end of the experiment, mammary tumors and thyroid glands were resected to compare their weights. Serum total iodine and thyroxin (T4) levels were measured. Immunohistochemical studies for bromodeoxyuridine (BrdU) labeling, transforming growth factor (TGF)-beta, and apoptosis were carried out in the resected tumor. Significant suppression of tumor growth was observed in groups I-B and I-C compared with I-A. In groups I-B and I-C, the weights of resected mammary tumors were significantly lower and serum total iodine concentration was significantly higher than in I-A. BrdU indices were significantly lower in groups I-B and I-C, compared with I-A. TGF-beta and apoptotic index were inversely related to BrdU. These results suggest that iodine is transported from the serum into mammary tissues and induces apoptosis through the expression of TGF-beta. In conclusion, wakame suppressed the proliferation of DMBA-induced mammary tumors.

9,10-Dimethyl-1,2-benzanthracene↗