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Hayakawa Y, Munehara H. Facultatively internal fertilization and anomalous embryonic development of a non-copulatory sculpin Hemilepidotus gilberti Jordan and Starks (Scorpaeniformes: Cottidae). JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY 2001; 256:51-58. [PMID: 11137504 DOI: 10.1016/s0022-0981(00)00303-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Fertilized residual eggs were observed in the ovaries of spent females of a non-copulatory sculpin Hemilepidotus gilberti Jordan and Starks. Fertilized eggs were present in 23 of 35 females, and approximately 38% of the total residual eggs (n=227) were fertilized. These eggs were thought to be fertilized facultatively with spermatozoa that entered the ovary through ovarian fluid during spawning. The high calcium concentration (1.42+/-0.21 mM kg(-1)) in ovarian fluid, which is beyond the threshold concentration required for fertilization, may allow internal fertilization to occur. Embryos at various developmental stages were observed, but all were deformed and surrounded by unhardened chorions. Since no larvae were observed, all the fertilized residual eggs would have degenerated in the ovary in accordance with other unfertilized residual eggs. These observations suggest that the ovary of the oviparous fish H. gilberti is an unsuitable environment for embryos to develop, possibly because it may be unable to supply developing embryos with needed elements, such as oxygen.
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352
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Hirose M, Kawai R, Hayakawa Y. Preparation of (R)-(-)-2-Methoxy-2'-(1H-tetrazol-5-yl)-1,1'-binaphthyl and (1R,2R)-(+)-1-Trimethylsilyl-2-(1H-tetrazol-5-yl)ferrocene: Optically Active Tetrazoles with Axial or Planar Chirality. Synlett 2000. [DOI: 10.1055/s-1997-6151] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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353
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Hayakawa Y, Hayashi T, Lee J, Srisomporn P, Maeda M, Ozawa T, Sakuragawa N. Inhibition of thrombin by sulfated polysaccharides isolated from green algae. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1543:86-94. [PMID: 11087944 DOI: 10.1016/s0167-4838(00)00193-x] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Eight different sulfated polysaccharides were isolated from Chlorophyta. All exhibited thrombin inhibition through a heparin cofactor II (HCII)-dependent pathway, and their effects on the inhibition of thrombin were more potent than those of heparin or dermatan sulfate. In particular, remarkably potent thrombin inhibition was found for the sulfated polysaccharides isolated from the Codiales. In the presence of these sulfated polysaccharides, both the recombinant HCII (rHCII) variants Lys(173)-->Leu and Arg(189)-->His, which are defective in interactions with heparin and dermatan sulfate, respectively, inhibited thrombin in a manner similar to native rHCII. This result indicates that the binding site of HCII for each of these eight sulfated polysaccharides is different from the heparin- or dermatan sulfate-binding site. All the sulfated polysaccharides but RS-2 significantly stimulated the inhibition of thrombin by an N-terminal deletion mutant of HCII (rHCII-Delta74). Furthermore, hirudin(54-65) decreased only 2-5-fold the rate of thrombin inhibition by HCII stimulated by the sulfated polysaccharides, while HD22, a single-stranded DNA aptamer that binds exosite II of thrombin, produced an approximately 10-fold reduction in this rate. These results suggest that, unlike heparin and dermatan sulfate, the sulfated polysaccharides isolated from Chlorophyta activate HCII primarily by an allosteric mechanism different from displacement and template mechanisms.
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354
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Yokomatsu T, Hayakawa Y, Kihara T, Koyanagi S, Soeda S, Shimeno H, Shibuya S. Synthesis and evaluation of multisubstrate analogue inhibitors of purine nucleoside phosphorylases. Bioorg Med Chem 2000; 8:2571-9. [PMID: 11092542 DOI: 10.1016/s0968-0896(00)00192-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
1,1-Difluoro-2-(tetrahydro-3-furanyl)ethylphosphonic acids (+/-)-cis-4a and (+/-)-trans-4a possessing a (purine-9-yl)methyl functionality at the ring as well as their homologues (+/-)-cis-4b and (+/-)-trans-4b were synthesized and tested as 'multi-substrate analogue' inhibitors for purine nucleoside phosphorylases. Radical cyclization of allylic alpha,alpha-difluorophosphonates 8a,b was applied to construct the alpha,alpha-difluorophosphonate-functionalized oxacycles 9a,b. The IC50 values of the nucleotide analogues (+/-)-cis-4a and (+/-)-cis-4b were 88 and 38 nM, respectively, for human erythrocyte PNP-catalyzed phosphorylation of inosine in the presence of 100mM orthophosphate. The stereochemistry of the inhibitors was found to affect significantly the inhibitory potency. The transisomers (+/-)-trans-4a and (+/-)-trans-4b were ca. 4-fold less potent than the corresponding cis-isomers. At an intracellular concentration of orthophosphate (1 mM), (+/-)-cis-4b, the most potent compound of this series, was shown to have IC50 and Ki values of 8.7 and 3.5 nM, respectively.
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355
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Nakamuta K, Shirono K, Matsunaga K, Murata I, Hayakawa Y, Murase K, Kohno S. [A case of ischemic colitis with skip lesions induced by colonoscopy]. NIHON SHOKAKIBYO GAKKAI ZASSHI = THE JAPANESE JOURNAL OF GASTRO-ENTEROLOGY 2000; 97:1283-7. [PMID: 11075594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
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356
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Hayakawa Y, Takagi M, Hasebe H, Hasegawa S, Takada R, Usui T, Abe H, Shibasaki K, Yaoeda H, Ukai K, Ishikawa N. A case of superior oblique myokymia observed by an image-analysis system. J Neuroophthalmol 2000; 20:163-5. [PMID: 11001191 DOI: 10.1097/00041327-200020030-00005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Superior oblique myokymia is a microtremor of the eye that causes monocular torsional oscillopsia. A modified Harada-Ito procedure was used to treat a case of the disease in a 20-year-old woman. The authors used video-image analysis pre- and postoperatively to evaluate the effect of the surgery on abnormal torsional eye movements. This analysis revealed that before surgery, the abnormal torsional movement had a very regular cycle (duration of attack, 8.0 +/- 0.5 s; time interval between attacks, 18.7 +/- 3.2 s; n = 9). After the surgery, amplitude of the abnormal torsional eye movement was reduced, and the oscillopsia had subjectively improved, although the movement cycle remained unchanged. The authors' video-image analysis, which used iris striation, proved to be a useful method for clinical measurement of torsional eye movements.
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357
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Kunishima A, Takemura G, Takatsu H, Hayakawa Y, Kanoh M, Qiu X, Fujiwara T, Fujiwara H. Mode and role of cell death during progression of atherosclerotic lesions in hypercholesterolemic rabbits. Heart Vessels 2000; 14:295-306. [PMID: 10901485 DOI: 10.1007/bf03257242] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
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.
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358
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Masuoka Y, Shin-Ya K, Furihata K, Matsumoto H, Takebayashi Y, Nagai K, Suzuki K, Hayakawa Y, Seto H. Diheteropeptin, a novel substance with TGF-beta-like activity, produced by a fungus, Diheterospora chlamydosporia. II. Physico-chemical properties and structure elucidation. J Antibiot (Tokyo) 2000; 53:793-8. [PMID: 11079801 DOI: 10.7164/antibiotics.53.793] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
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.
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359
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Masuoka Y, Shin-Ya K, Kim YB, Yoshida M, Nagai K, Suzuki K, Hayakawa Y, Seto H. Diheteropeptin, a new substance with TGF-beta-like activity, produced by a fungus, Diheterospora chlamydosporia. I. Production, isolation and biological activities. J Antibiot (Tokyo) 2000; 53:788-92. [PMID: 11079800 DOI: 10.7164/antibiotics.53.788] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A new metabolite, diheteropeptin, was found in the culture broth of Diheterospora chlamydosporia Q58044 by screening for TGF-beta-like active substances. Diheteropeptin was extracted from the culture supernatant and purified by a series of chromatographies such as silica gel, gel filtration and HPLC. Diheteropeptin exhibited cytostatic activity in Mv1Lu cells with an IC50 value of 20.3 microM and inhibited histone deacetylase.
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360
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Tomikawa T, Shin-Ya K, Furihata K, Kinoshita T, Miyajima A, Seto H, Hayakawa Y. Rasfonin, a new apoptosis inducer in ras-dependent cells from Talaromyces sp. J Antibiot (Tokyo) 2000; 53:848-50. [PMID: 11079809 DOI: 10.7164/antibiotics.53.848] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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361
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Kataoka M, Kawai R, Hayakawa Y. A facile synthesis of DNA oligomers with modified backbones via the phosphoramidite method without nucleoside base protection. NUCLEIC ACIDS SYMPOSIUM SERIES 2000:105-6. [PMID: 10780401 DOI: 10.1093/nass/42.1.105] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
A convenient synthesis of DNA oligomers with modified back bones including phosphorothioates and phosphotriesters has been developed on the basis of the phosphoramidite strategy without nucleoside base protection. In this synthesis, a new, convenient method for the preparation of N-free-5'-O-dimethoxytrityl-2'-deoxyribonucleoside by the direct O-selective dimethoxytritylation of the parent nucleosides has also been disclosed.
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362
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Yokomatsu T, Hayakawa Y, Abe H, Shibuya S, Kihara T, Soeda S, Shimeno H. Synthesis of novel nucleotide analogues possessing a difluoromethylenephosphonato group. Evaluation of the inhibitory activity for purine nucleoside phosphorylase. NUCLEIC ACIDS SYMPOSIUM SERIES 2000:27-8. [PMID: 10780362 DOI: 10.1093/nass/42.1.27] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Novel nucleotide analogues 1-6 were prepared as "multi-substrate" analogue inhibitors for purine nucleoside phosphorylases (PNPs). The cyclopropane and the tetrahydrofuran moieties of the alkyl spacer connecting a nucleobase and difluoromethylene phosphonic acid were found to be effective for good inhibition of PNPs.
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363
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Ikeda T, Murakami K, Sakukaw R, Hayakawa Y, Saiki I. Characterization of a liver metastatic variant of murine K1735M2 melanoma cells. In Vivo 2000; 14:519-27. [PMID: 10945168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
Intraportal vein injection of highly metastatic K1735M2L5 cells consistently resulted in liver metastases (increases in the number of tumor nodules in the liver), whereas inoculation of K1735M2 cells rarely did so. K1735M2L5 cells invaded the basement membrane Matrigel in greater numbers than did K1735M2 cells, suggesting that the metastatic potential of K1735M2L5 cells is partly related to enhanced invasive properties. The adhesion to Matrigel- and laminin-coated substrates was enhanced in K1735M2L5 cells. The up-regulated expression of VLA-4 and VLA-6 on the surface of K1735M2L5 cells was detected by flow cytometry. The RT-PCR and gelatin zymography study revealed that the secretion of MMP-2 was higher in K1735M2L5 cells than in K1735M2 cells. These results indicate that the invasive ability of K1735M2L5 cells may also be attributed to enhanced gelatinolytic activity as well as adhesiveness. K1735M2L5 cells grew more rapidly than K1735M2 cells and showed fibroblastoid morphology with loose cell-cell contacts as compared with K1735M2 cells. Thus, experimental models using highly metastatic K1735M2L5 cells would be useful for analyzing the molecular mechanism of tumor metastasis and for evaluating the efficacy of treatments for metastases which may have already occurred at the time of the diagnosis.
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364
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Hayakawa Y, Ukai K, Takagi M, Shiratori A, Ishikawa N, Hasebe H, Takada R, Usui T, Hasegawa S, Abe H. [Quantitative evaluation of nystagmus by an image-analysis system]. NIPPON GANKA GAKKAI ZASSHI 2000; 104:424-30. [PMID: 10885277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
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.
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365
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Kost'ál V, Noguchi H, Shimada K, Hayakawa Y. Circadian component influences the photoperiodic induction of diapause in a drosophilid fly, Chymomyza costata. JOURNAL OF INSECT PHYSIOLOGY 2000; 46:887-896. [PMID: 10802100 DOI: 10.1016/s0022-1910(99)00195-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The last-instar larvae of a drosophilid fly, Chymomyza costata enter diapause in response to the dark-phases longer than 9 h (Yoshida, T., Kimura, M.T., 1995. The photoperiodic clock in Chymomyza costata. Journal of Insect Physiology 41, 217-222). In order to switch the developmental programming of the sensitive larvae from continuous development to diapause, after they were transferred from the short (8 h) to the long (14 h) dark-phase, significantly less time (1-2 days) was required when the dark-phase was abruptly and asymmetrically extended into the evening, than when it was extended symmetrically into both morning and evening (2-3 days), or asymmetrically into the morning hours (4-6 days). Diapause was also induced in 40-70% of sensitive larvae that were reared under the gradually shortening light-phase (from 16 h to 2 h, by 1 h in each cycle), despite that the dark-phase remained constant and short (8 h). Larvae developed continuously, however, when reared under the gradually extending light-phase (from 16 h to 24 h) and a constantly short dark-phase. We interpret such results, with the help of the two-oscillator model of circadian rhythmicity (Pittendrigh, C.S., Daan, S., 1976. A functional analysis of circadian pacemakers in nocturnal rodents. V. Pacemaker structure: A clock for all seasons. Journal of Comparative Physiology A 106, 333-355), as indicating that two mutually coupled oscillators (evening and morning) differing in their entrainability may participate in measuring of the dark-phase duration. The levels of dopamine (DA) and serotonin (5-HT) in the larval CNS transiently increased (by up to 20%) after the dusk, while no apparent change was observed during the dawn. The dusk-related increase was observed also after the asymmetric extension of the dark-phase into evening, while the asymmetric extension into morning had no effect on the levels of the DA and 5-HT.
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366
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Manabe T, Togashi H, Uchida N, Suzuki SC, Hayakawa Y, Yamamoto M, Yoda H, Miyakawa T, Takeichi M, Chisaka O. Loss of cadherin-11 adhesion receptor enhances plastic changes in hippocampal synapses and modifies behavioral responses. Mol Cell Neurosci 2000; 15:534-46. [PMID: 10860580 DOI: 10.1006/mcne.2000.0849] [Citation(s) in RCA: 130] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Cadherins organize symmetrical junctions between the pre- and postsynaptic membranes in central synapses. One of them, cadherin-11 (cad11), is expressed in the limbic system of the brain, most strongly in the hippocampus. Immunohistochemical studies of the hippocampus showed that cad11 proteins were densely distributed in its synaptic neuropil zones; in cultured hippocampal neurons, their distribution often overlapped with that of synaptophysin, and also occasionally with that of GluR1 at spines. To assess the role of cad11 in synaptic formation and/or function, we analyzed brains of cad11-deficient mice. In these mice, long-term potentiation (LTP) in the CA1 region of the hippocampus was, unexpectedly, enhanced; and the level of LTP saturation was increased. In behavioral tests, the mutant mice showed reduced fear- or anxiety-related responses. These results suggest that the cad11-mediated junctions may modulate synaptic efficacy, confining its dynamic changes to a limited range, or these junctions are required for normal development of synaptic organization in the hippocampus.
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367
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Takeda K, Hayakawa Y, Atsuta M, Hong S, Van Kaer L, Kobayashi K, Ito M, Yagita H, Okumura K. Relative contribution of NK and NKT cells to the anti-metastatic activities of IL-12. Int Immunol 2000; 12:909-14. [PMID: 10837418 DOI: 10.1093/intimm/12.6.909] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Conventional T cells, NK cells and NKT cells have been implicated in the anti-tumor activities induced by IL-12. Here we show that IL-12-induced immune responses are partially impaired in T and NKT cell-deficient RAG-2(-/-) mice, and in NKT cell-deficient CD1(-/-) mice. In response to a small dose (<1000 U) of IL-12, RAG-2(-/-) and CD1(-/-) mice demonstrated reduced cytotoxicity, serum IFN-gamma elevation and anti-metastatic activities; in contrast, in response to a high dose (>2000 U) of IL-12, the IL-12-induced immune responses of RAG-2(-/-) and CD1(-/-) mice were indistinguishable from wild-type mice. The defective responses to low-dose IL-12 of RAG-2(-/-) mice were corrected by adoptive transfer of NKT cells but not NK cells. These findings indicate that both NK and NKT cells contribute to the anti-metastatic responses induced by IL-12, and that NKT cells are mostly responsible for the low-dose activities of this cytokine.
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368
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Hayakawa Y, Ohnishi A, Mizoguchi A, Yamashika C. Distribution of growth-blocking peptide in the insect central nervous tissue. Cell Tissue Res 2000; 300:459-64. [PMID: 10928276 DOI: 10.1007/s004419900152] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Parasitization of the armyworm Pseudaletia separata by the endoparasitic wasp Cotesia kariyai inhibits larval growth and delays pupation, conditions necessary for proper maturation of the parasite larvae. Parasitization is correlated with an elevated level of a 25-amino-acid hormone-like peptide, growth-blocking peptide (GBP, ENFSGGCVAGYMRTPDGRCKPTFYQ). Injection of synthetic GBP into nonparasitized larvae dose dependently mimics the effects of parasitization by delaying the larval development. Here we studied the relationship between parasitization and both the production and distribution of GBP in central nervous tissues. We found that parasitization is correlated with an elevated expression of GBP mRNA, and increased concentrations of both proGBP and GBP in the host insect brain and subesophageal ganglion. The increase in proGBP precedes that of the mature GBP by about 12 h. In situ hybridization analysis using sections of parasitized and nonparasitized larval brains showed strong expression of GBP mRNA in perineural cells and/or class I neuroglia in the rind of both larval brains. The expression in parasitized larval brain-subesophageal ganglion is approximately two- to threefold higher than that in nonparasitized larvae. The presence of GBP in insect neural tissue, and its role in inhibiting growth, suggest an involvement in the regulation of neurosecretory cells.
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Lamensdorf I, Eisenhofer G, Harvey-White J, Hayakawa Y, Kirk K, Kopin IJ. Metabolic stress in PC12 cells induces the formation of the endogenous dopaminergic neurotoxin, 3,4-dihydroxyphenylacetaldehyde. J Neurosci Res 2000; 60:552-8. [PMID: 10797558 DOI: 10.1002/(sici)1097-4547(20000515)60:4<552::aid-jnr14>3.0.co;2-u] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
3,4-Dihydroxyphenylacetaldehyde (DOPAL) has been reported to be a toxic metabolite formed by the oxidative-deamination of dopamine (DA) catalyzed by monoamine oxidase. This aldehyde is either oxidized to 3,4-dihydroxyphenylacetic acid (DOPAC) by aldehyde dehydrogenase, an NAD-dependent enzyme or reduced to 3, 4-dihydroxyphenylethanol (DOPET) by aldehyde or aldose reductase. In the present study we examined whether levels of DOPAL are elevated by inhibition of the mitochondrial respiratory chain. Using inhibitors of mitochondrial complexes I, II, III and IV we found that inhibition of complex I and III increased levels of DOPAL and DOPET. Nerve growth factor-induced differentiation of PC12 cells markedly potentiated DOPAL and DOPET accumulation in response to metabolic stress. DOPAL was toxic to differentiated PC12 as well as to SK-N-SH cell lines. Because complex I dysfunction has been implicated in the pathogenesis of Parkinson's disease, the accumulation of DOPAL may explain the vulnerability of the dopaminergic system to complex I inhibition. The rapid appearance of DOPAL and DOPET after inhibition of complex I may be a useful early index of oxidative stress in DA-forming neurons.
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Takeda K, Hayakawa Y, Van Kaer L, Matsuda H, Yagita H, Okumura K. Critical contribution of liver natural killer T cells to a murine model of hepatitis. Proc Natl Acad Sci U S A 2000; 97:5498-503. [PMID: 10792025 PMCID: PMC25857 DOI: 10.1073/pnas.040566697] [Citation(s) in RCA: 441] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Natural killer T (NKT) cells constitute a distinct subpopulation of T cells with a unique antigen specificity, prompt effector functions, and an unusual tissue distribution. NKT cells are especially abundant in the liver, but their physiological function in this organ remains unclear. In the present study, we examined the possible contribution of NKT cells to a murine model of hepatitis induced by i.v. injection of Con A. CD1-deficient mice lacking NKT cells were highly resistant to Con A-induced hepatitis. Adoptive transfer of hepatic NKT cells isolated from wild-type mice, but not from FasL-deficient gld mice, sensitized CD1-deficient mice to Con A-induced hepatitis. Furthermore, adoptive transfer of hepatic mononuclear cells from wild-type mice, but not from CD1-deficient mice, sensitized gld mice to Con A-induced hepatitis. Upon Con A administration, hepatic NKT cells rapidly up-regulated cell surface FasL expression and FasL-mediated cytotoxicity. At the same time, NKT cells underwent apoptosis leading to their rapid disappearance in the liver. These results implicated FasL expression on liver NKT cells in the pathogenesis of Con A-induced hepatitis, suggesting a similar pathogenic role in human liver diseases such as autoimmune hepatitis.
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371
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Strand MR, Hayakawa Y, Clark KD. Plasmatocyte spreading peptide (PSP1) and growth blocking peptide (GBP) are multifunctional homologs. JOURNAL OF INSECT PHYSIOLOGY 2000; 46:817-824. [PMID: 10742531 DOI: 10.1016/s0022-1910(99)00171-7] [Citation(s) in RCA: 91] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
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.
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372
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Hayakawa Y, Sawada Y. Learning-induced synchronization of a globally coupled excitable map system. PHYSICAL REVIEW. E, STATISTICAL PHYSICS, PLASMAS, FLUIDS, AND RELATED INTERDISCIPLINARY TOPICS 2000; 61:5091-5097. [PMID: 11031551 DOI: 10.1103/physreve.61.5091] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/1999] [Indexed: 05/23/2023]
Abstract
We propose a pulse-coupled neural network model in which one-dimensional excitable maps connected in a time-delayed network serve as the neural processing units. Although the individual processing unit has simple dynamical properties, the network exhibits collective chaos in the active states. Introducing a Hebbian learning algorithm for synaptic connections enhances the synchronization of excitation timing of the units within a subpopulation. The synchronizing clusters approximately exhibit a power-law size distribution, suggesting a hierarchy of synchronization. After applying a stationary signal to a subpopulation of the units with learning, the network then reproduces the signal. The learnable time range is much longer than the inherent time scale of the processing units, i.e., the synaptic delay time. Also, the network can reproduce periodic signals with time resolution finer than the delay time. Our present network model can be considered as a temporal association device which operates in chaotic states.
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373
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Nakasato T, Katoh K, Ehara S, Tamakawa Y, Hayakawa Y, Chiba H, Murai K. Virtual CT endoscopy in determining safe surgical entrance points for paranasal mucoceles. J Comput Assist Tomogr 2000; 24:486-92. [PMID: 10864091 DOI: 10.1097/00004728-200005000-00024] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The goal of this work was to evaluate virtual CT endoscopy for determining safe surgical entrance points for paranasal mucoceles. Twelve mucoceles in 11 cases were scanned with helical CT, and multiplanar reconstruction (MPR) and virtual endoscopic images were obtained. After a safe surgical entrance point was determined by MPR images, the entrance point was specified on the virtual endoscopic images. The combination of virtual endoscopic images and MPR images is a suitable method for determining a safe surgical entrance point for simple mucoceles.
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374
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Abstract
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.
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375
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Hayakawa Y, Hayashi T, Lee JB, Ozawa T, Sakuragawa N. Activation of heparin cofactor II by calcium spirulan. J Biol Chem 2000; 275:11379-82. [PMID: 10753952 DOI: 10.1074/jbc.275.15.11379] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Heparin cofactor II (HCII) is a plasma serine protease inhibitor whose ability to inhibit alpha-thrombin is accelerated by a variety of sulfated polysaccharides in addition to heparin and dermatan sulfate. Previous investigations have indicated that calcium spirulan (Ca-SP), a novel sulfated polysaccharide, enhanced the rate of inhibition of alpha-thrombin by HCII. In this study, we investigated the mechanism of the activation of HCII by Ca-SP. Interestingly, in the presence of Ca-SP, an N-terminal deletion mutant of HCII (rHCII-Delta74) inhibited alpha-thrombin, as native recombinant HCII (native rHCII) did. The second-order rate constant for the inhibition of alpha-thrombin by rHCII-Delta74 was 2.0 x 10(8) M(-1) min(-1) in the presence of 50 microgram/ml Ca-SP and 10, 000-fold higher than in the absence of Ca-SP. The rates of native rHCII and rHCII-Delta74 for the inhibition of gamma-thrombin were increased only 80- and 120-fold, respectively. Our results suggested that the anion-binding exosite I of alpha-thrombin was essential for the rapid inhibition reaction by HCII in the presence of Ca-SP and that the N-terminal acidic domain of HCII was not required. Therefore, we proposed a mechanism by which HCII was activated allosterically by Ca-SP and could interact with the anion-binding exosite I of thrombin not through the N-terminal acidic domain of HCII. The Arg(103) --> Leu mutant bound to Ca-SP-Toyopearl with normal affinity and inhibited alpha-thrombin in a manner similar to native rHCII. These results indicate that Arg(103) in HCII molecule is not critical for the interaction with Ca-SP.
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