Biomedical subjects
Publications and source records attributed to Y Hayakawa.
The structure of diheteropeptin (1), a TGF-beta-like active substance from Diheterospora chlamydosporia Q58044, was determined to be a new cyclotetrapeptide, cyclo[2aminoisobutyryl-(S)-phenylalanyl-(R)-prolyl-(2S,8R,9R)-2-am ino-8,9-dihydroxydecanoyl-] by NMR, mass spectrometric and chemical studies.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
PURPOSE: We attempted to apply a newly developed image-analysis system for measurement and analysis of nystagmus. METHOD: Eye movements were recorded by digital video through a head-mounted charge coupled device (CCD) camera. The recorded movie was converted into black and white in order to detect the area of the pupil. Horizontal and vertical eye positions were determined by calculating the centroid of the pupil. Torsional angle was calculated using the iris striate pattern around the pupillary margin. RESULTS: The parameters (amplitude, cycle, etc.) of nystagmus were calculated easily by the new image-analysis system from the recorded images. As examples, the foveation period was measured accurately in a case of jerky-type congenital nystagmus. Very regular cycles of intorsional attack period were revealed in a case of superior oblique myokymia. A case of cork-screw-like nystagmus showed a characteristic combination of large and small cycles unassociated with torsion. CONCLUSION: This image-analysis system was useful for quantitative analysis of nystagmus, and especially for measurement of torsion. Detailed waveforms and specific rhythms of nystagmus, which could not be recognized by observation, were demonstrated by this system.
A case of primary liposarcoma of the cervix is described in a 49-year-old woman with a fungating cervical mass which was diagnosed as liposarcoma on the basis of cytologic features and the intracellular lipids. Most of the adipocytes and vacuolated lipoblasts were positive for S- 100 protein. The mass was well circumscribed and limited to the superficial cervical stroma. A total abdominal hysterectomy and bilateral salpingo-oophorectomy with pelvic lymphadenectomy was performed. There was no clinical evidence of metastasis two years after the operation.
Explore the source record for details and available documents.
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.
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.
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.
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.
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.
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.
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.
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.
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.
Two cell types, macrophages and smooth muscle cells (SMCs), play important roles in the development of atherosclerotic lesions. Both contribute to the formation of the lesions not only by their presence but also by taking in or releasing extracellular substrates during life and at death. The present study aimed to elucidate their turnover, focusing on the detailed description of the modes of death in each cell type, and the roles of their death in the progression from early into advanced atherosclerotic lesions. Ascending aortas were obtained from New Zealand white male rabbits fed a diet with 1% cholesterol for 3 months (3-M group, n= 6) and 6 months (6-M group, n = 6). They were histologically examined, and the cell death was checked by in situ nick end-labeling (TUNEL), using a Taq polymerase-based in situ ligation assay with/without combination of immunohistochemistry, electron microscopy (EM), and TUNEL at the EM level. Intimal hyperplasia and luminal stenosis advanced with increased dietary interval, and the aortic intima of the 3-M group consisted of histological types I-III atherosclerotic lesions, whereas that of the 6-M group included types III-V. Along with the progression, the cellular population decreased, but the area of fibrosis increased. The percentage area of macrophages declined (from 60% +/- 5% to 23% +/- 2%), but that of SMCs increased (from 5% +/- 1% to 10% +/- 2%). The positive cells for in situ ligation were less frequent in the 6-M group (0.05% +/- 0.01%) than in the 3-M group (0.2% +/- 0.04%), which was due to a decrease in SMCs positive for in situ ligation. The frequency of TUNEL-positive cells was higher than that of in situ ligation-positive cells in both groups, suggesting that cell death involved not only apoptosis but also oncosis. This was confirmed using EM: cell death occurred via both apoptosis and oncosis. EM-TUNEL positively labeled not only apoptotic but also some oncotic nuclei. Death of macrophages and SMCs involves both apoptosis and oncosis in the aortic intima of hypercholesterolemic rabbits. Decline in the dying rate of SMCs might be associated with the formation of SMC-rich and collagen-rich lesions in the late advanced stage of atherosclerosis, although such a cause-effect relationship is to be further confirmed.
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.