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Biomedical subjects

A Hayashi

Publications and source records attributed to A Hayashi.

At least 217 records · Page 12Linked to original sources
PubMed1996

Increase of protein tyrosine phosphorylation in rat retina after ischemia-reperfusion injury.

PURPOSE: This study was conducted to examine the effect of retinal ischemia-reperfusion injury on protein tyrosine phosphorylation, the production of angiogenic growth factors, and the activation of signal proteins in tyrosine kinase pathways. METHODS: Ischemia-reperfusion injury was induced in rats by compression of the optic nerve for 2 hours. The rats were killed, and the retinas were collected at 0, 1, 6, 24, 48, 96, or 168 hours of reperfusion. Tyrosine phosphorylation of proteins in the retina was examined by Western blot analysis and immunohistochemistry. Angiogenic growth factors and their receptors, such as basic fibroblast growth factor (bFGF) and Flg, vascular endothelial growth factor (VEGF) and Flk-1, platelet-derived growth factor (PDGF)-B chain and PDGF-beta receptor, and five intracellular signal proteins (phosphatidylinositol 3-kinase [PI3K], phospholipase C gamma [PLC gamma], C-Src, SHC, and mitogen-activated protein kinase [MAPK]) were examined by Western blot analysis. RESULTS: Protein tyrosine phosphorylation increased after ischemia-reperfusion injury, reaching a peak at 48 hours of reperfusion. Increased staining of tyrosine-phosphorylated proteins in the inner retina were evident on immunohistochemical examination. The amount of bFGF decreased after injury, but the amounts of VEGF and PDGF-B chain increased. Tyrosine phosphorylation of PLC gamma, SHC, and MAPK was increased at 48 hours of reperfusion, and tyrosine phosphorylation of PDGF-beta receptor and PI3K was increased at 168 hours of reperfusion. CONCLUSIONS: Ischemia-reperfusion injury in the rat retina leads to activation of the tyrosine kinase pathway, increasing the amounts of angiogenic growth factors. The resultant activation of signal proteins PLC gamma, SHC, MAPK, PI3K, and PDGF-beta receptor may play an important role in ischemia-induced retinal changes such as cell proliferation.

Animals↗
PubMed1995

Establishment of an enzyme-linked immunosorbent assay (ELISA) for measuring cellular MAGE-4 protein on human cancers.

The MAGE genes encoding tumor-rejection antigens are expressed on various human cancers. An enzyme-linked immunosorbent assay (ELISA) was established for measuring cellular MAGE-4 protein (MAGE-4a and/or -4b) expressed on human tumor cells using a monoclonal antibody (mAb) and polyclonal Ab to recombinant MAGE-4b protein. Both the R5 mAb (IgG1) and the polyclonal Ab recognized a 45 kDa protein in extracts of MAGE-4 mRNA positive cancers, and showed no apparent cross-reactivity to the other MAGE gene products (MAGE-1, -2, -3, -6, and -12) by the immunoblot analyses. The R5 mAb and the polyclonal Ab primarily recognized one (the position 119-133) and two oligopeptides (the positions 119-133 and 259-273), respectively, among a series of 31 different MAGE-4b oligopeptides. The amino acid sequences of these two peptides were identical to those of MAGE-4a and -4b, but differed from those of all the other MAGE proteins (MAGE-1, -2, -3, -6, and -12). Substitution of glycine for amino acid in position 123 (arginine, R), 124 (lysine, K), 126 (R) or 128 (K) in a MAGE-4b oligopeptide of the position 119-132 severely decreased the reactivity of the R5 mAb to the oligopeptide. This ELISA also showed no apparent cross-reactivity with the other MAGE gene products (MAGE-1, -2, -3, -6, and -12). The minimum detectable level of MAGE-4 protein was determined to be 10 pg/well (100 pg/ml). The results suggest that this ELISA is a reliable and quantitative method to measure cellular MAGE-4 protein that is a potential target molecule for specific immunotherapy of human cancers.

Amino Acid Sequence↗
PubMed1995

Surgical treatment for patients with pulmonary metastases after resection of primary colorectal carcinoma.

BACKGROUND: The optimum treatment for patients with pulmonary metastases from colorectal carcinoma is still controversial. METHODS: To evaluate the results of pulmonary resection in 22 patients with pulmonary metastases after resection of primary colorectal carcinoma, patients' characteristics were examined retrospectively. Eighteen patients had a solitary metastatic lesion and four had two lesions. RESULTS: Postthoracotomy recurrence occurred in 17 of the 22 patients (77.3%), and showed no correlation with the type of pulmonary resection. In 11 patients with a solitary lesion of less than 3.0 cm in greatest dimension, the 3- and 5-year postthoracotomy survival rates (PTSR) were 71.6% and 36.8%, respectively. Six of these patients received two or more thoracotomies for pulmonary recurrence. The 3-year PTSR for seven patients with a solitary lesion greater than or equal to 3.0 cm was 19.0%, and for the four patients with two lesions, 25.0%. A significant difference was noted in the survival rate according to both number and size of the metastatic lesions (P < 0.05). CONCLUSIONS: The number and size of metastatic lesions appear to be important prognostic determinants. Repeated thoracotomy can prolong survival for selected patients.

Adenocarcinoma↗
PubMed1995

The human gene encoding the largest subunit of RNA polymerase II.

The nucleotide sequence of a large portion of the human RNA polymerase II large subunit (RpII LS)-encoding gene and its whole gene structure were determined. The RpIILS gene consists of 29 exons. The sequence of the 5' flanking region is highly conserved as compared with that of the mouse RpIILS and contains several SP1-binding sites, a CCAAT sequence and a sequence homologous to a heat-shock element. In addition, several inverted repeats and palindrome sequences were involved in the 5' upstream region. Those suggest that the 5' flanking domain of RpIILS would be highly structured which may be responsible for transcriptional regulation.

Amino Acid Sequence↗
PubMed1995

Detection of MAGE-4 protein in lung cancers.

Expression of genes of the MAGE family, which encode tumor-rejection antigens recognized on HLA-AI and -Cw1601 by cytotoxic T lymphocytes (CTL), was investigated in lung cancers at the mRNA [MAGE-1, -2, -3/-6, and -4 (4a and/or 4b)] and protein (MAGE-4) levels. MAGE-1, -2, -3/-6 and -4 genes were expressed, respectively, at the mRNA level in 6, 7, 20 and 7 of 53 lung cancers (50 non-small-cell lung cancers and 3 small-cell lung cancers) by the reverse transcription-polymerase chain reaction (RT-PCR) method. Polyclonal antibody (Ab) and monoclonal antibody (MAb) against recombinant MAGE-4b protein were developed to detect MAGE-4 protein. Both the polyclonal Ab and the R5 MAb recognized a 45-kDa protein in extracts of MAGE-4 mRNA-positive lung cancers, and showed no apparent cross-reactivity with the other MAGE gene products except with MAGE-4a by immunoblot analyses and transfection experiments. MAGE-4 protein was detected on 13 of 44 (30%) lung cancers (18 to 55,989 pg/mg) by ELISA with the polyclonal Ab and R5 MAb. These 13 lung cancers consisted of 6 of 6 MAGE-4 mRNA-detectable and 7 of 38 MAGE-4 mRNA-undetectable lung cancers. Histologically, these comprised 7 of 10 squamous-cell carcinomas, 4 of 30 adenocarcinomas and 2 of 3 small-cell lung cancers. The proportions of MAGE gene-positive samples, at both the mRNA and protein levels, correlated with the size of the primary tumors and with regional node involvement. These results should provide important information on specific immunotherapy of lung cancers using MAGE gene products.

Animals↗
PubMed1995

Presence of elastin-related 45-kDa fragment in culture medium: specific cleavage product of tropoelastin in vascular smooth muscle cell culture.

Significant amount of 45-kDa polypeptide was found to be present in the cultured medium of chick aortic smooth muscle cells. The polypeptide as well as tropoelastin (65-kDa) reacted with monoclonal antibody for tropoelastin. Pulse-chase experiments revealed that the relative density of the 45-kDa polypeptide to tropoelastin increased with chase periods. Partially purified radioactive tropoelastin (65-kDa) was converted to a 45-kDa polypeptide fragment in the test tube. The processing from the 65- to the 45-kDa polypeptide in the test tube was inhibited by ethylenediaminetetraacetic acid but not by N-ethylmaleimide and aminophenylmethylsulfonyl fluoride. These results indicate that the 45-kDa fragment is a degradation product of tropoelastin and that processing is mediated by enzymatic cleavages with metal proteinase. Fully hydroxylated tropoelastin treated with ascorbic acid was more resistant to the enzymes than underhydroxylated tropoelastin with scorbutic condition, suggesting that the structural stability of tropoelastin is also involved in the processing rate.

Animals↗
PubMed1995

Left partial anomalous pulmonary venous connection found during a lobectomy for lung cancer: report of a case.

We report herein the case of a 68-year-old man in whom a partial anomalous pulmonary venous connection (PAPVC) was found during an operation for primary lung cancer. The preoperative clinical findings did not suggest a vascular shunt, and intraoperatively the anomalous vein was seen to drain only from the left upper lobe into the left innominate vein. The lower pulmonary vein connected normally, and there was no atrial septal defect nor any other anomalous condition. A left upper lobectomy with ligation of the anomalous connected vein was performed uneventfully. This type of PAPVC is extremely rare, and is especially noteworthy because there were no clinical signs.

Aged↗
PubMed1995

Stimulation of elastin expression by minoxidil in chick skin fibroblasts.

Minoxidil inhibited the proliferation of embryonic skin fibroblasts during the growth phase but not during the stationary phase. Minoxidil stimulated elastin synthesis two-fold in a dose-dependent manner at a concentration of 1 mM during the stationary phase. The stimulation of elastin synthesis paralleled a comparable increase in elastin mRNA level. These results suggest that the stimulation of elastin expression by minoxidil in skin fibroblasts was controlled at the elastin mRNA level and also suggest that its elastin-stimulating effect is not related to the suppressive effect on cell proliferation. Minoxidil appears to be a potent stimulator for elastin expression in skin fibroblasts.

Animals↗
PubMed1995

Partial characterization of a unique 84-kDa polypeptide stimulated by ascorbic acid in skin fibroblasts.

Ascorbic acid stimulated the synthesis of a noncollagenous 84 kDa polypeptide by up to 3.5-fold in primary cultures of chick skin fibroblasts. Stimulation was observed with concentrations ranging 0.4 to 50 micrograms/ml and was dose-dependent within the concentrations up to 10 micrograms/ml during 24 h treatment under conditions in which procollagen synthesis was increased. This protein was found to be translated with a molecular size of 84 kDa in an in vitro cell-free translation experiment, indicating that the 84 kDa polypeptide was a primary translate. The stimulation was accompanied by a 1.7-fold increase in translational activity of the mRNA for this polypeptide. Its synthesis rapidly reduced when the cells were serially passaged until the third subcultivation, whereas procollagen synthesis remained essentially constant. These results indicate that the stimulation of this unique 84 kDa polypeptide by ascorbic acid was modulated at least in part at a translational level and its synthesis appears to be related to in vitro cellular aging.

Animals↗
PubMed1995

Three-dimensional display of the pelvic structure of anorectal malformations based on CT and MR images.

Three-dimensional images of the pelvic structure of patients with anorectal malformation (ARM) were constructed by computer graphics based on radiographic computerized tomography (CT) and magnetic resonance (MR) images. Organ contour data from CT images and raw MR image data were transferred to a personal computer and to a graphic workstation respectively. On MR image processing, organs were extracted semiautomatically by thresholding enclosed areas. After several steps of image processing, three-dimensional anatomy of each anomaly was visualized with emphasis on position and shape of the muscle complex. In control patients without an anomaly, images showed that the rectum is supported by the levator muscle from behind and descends along with the urethra. In the male patient, the anal canal separates from the urethra and penetrates through the middle of the sphincter complex to reach the orifice. In those with low-type anomaly with a fistula opening to the perineum or the vestibule, images showed the fistula descending through the anterior portion of the sphincter complex. Images of those with a rectourethral fistula could show the muscle complex behind the rectum and at the region where the external sphincter should be. In those with cloacal anomalies, anatomical position and the shape of three different viscera were easily recognized, and the muscle complex was shown like that of rectourethral-type anomalies. This study is a new approach to the anomaly to facilitate understanding it and can assist a surgeon in planning a procedure. This kind of application would make it possible for a surgeon to consider the strategy on a display screen before the real surgery.

Anal Canal↗
PubMed1995

Modulations of elastin expression and cell proliferation by retinoids in cultured vascular smooth muscle cells.

Effects of retinoid derivatives (retinol, retinal, retinoic acid, and etretinate) on elastin expression and cell proliferation in chick embryonic vascular smooth muscle cells were compared. Retinoic acid and etretinate inhibited cell proliferation to a greater extent than retinol and retinal. Retinol showed no significant effect on cell proliferation or elastin synthesis. Retinoic acid exhibited the most pronounced stimulatory effect on elastin synthesis with a maximum stimulation of 2.8-fold at the concentration of 10(-6) M for 24-48 h treatment. A comparable increase in elastin mRNA level was observed in the case of retinoic acid treatment. When the cells were serially passaged to the third subcultivation, elastin synthesis declined with increasing number of cell passages. Retinoic acid reversed this decline of elastin synthesis. The results indicate that retinoic acid was potentially active and retinol was inactive for both inhibition of cell proliferation and stimulation of elastin synthesis. The inhibitory activities of the four compounds for cell proliferation appear to parallel the stimulatory activities for elastin synthesis. The stimulation of elastin expression by retinoids may thus be closely related to the inhibition of cell proliferation.

Animals↗
PubMed1995

Case report: thyrotropin-releasing hormone-induced myoclonus and tremor in a patient with Hashimoto's encephalopathy.

The authors investigated the possibility of a thyrotropin-releasing hormone-related mechanism in a 43-year-old Japanese woman with Hashimoto's encephalopathy who experienced three relapses closely associated with the menstrual cycle. Her symptoms began at ovulation, worsened during the luteal phase, and improved during the menstruation phase. No abnormalities were found by brain magnetic resonance imaging and cerebral angiography. Intravenous administration of thyrotropin-releasing hormone induced symptoms of myoclonus and tremor similar to those observed during an exacerbation. The intensity and duration of involuntary movements induced by thyrotropin-releasing hormone were dose-dependent. The patient's symptoms were controlled effectively by thyroxine replacement therapy. On the basis of these findings, thyrotropin-releasing hormone may have an important role in Hashimoto's encephalopathy.

Adult↗
PubMed1995

Alteration of the hypothalamus-pituitary-testis axis in oligozoospermic men with normal gonadotropin levels.

BACKGROUND: Serum basal hormone levels such as lutenizing hormone (LH), follicle-stimulating hormone (FSH), and testosterone, which is important to regulate testicular function, do not necessarily indicate the normal integrity of the hypothalamic-pituitary-testicular axis and the static measurement is not enough to detect the endocrine disorder. The dynamic measurement of gonadal hormone by GnRH test is considered to be more helpful to understanding the endocrine regulation of spermatogenesis. In this study, we performed GnRH test in oligozoospermic patients with normal levels of LH and FSH to examine the subtle alteration of hypothalamic-pituitary-testis axis. METHODS: GnRH test was performed in 41 patients with oligozoospermia and normal gonadal hormone levels. RESULTS: The responses of LH and/or FSH were excessive in most patients in spite of their normal gonadotropin levels. The patients with sperm concentration < 10 x 10(6)/ml had significantly higher peak levels of both LH and FSH than did those with sperm concentration > 10 x 10(6)/ml. In the patients with normal peak levels of both LH and FSH, sperm concentration was significantly higher than those with exceeded peak levels of FSH and/or LH after GnRH test. No significant differences were observed in estradiol, testosterone, free testosterone, or prolactin (PRL) levels between patients with normal responses and abnormal responses of LH and/or FSH. CONCLUSIONS: The feedback control of gonadotropin release from testis was worse in more severely oligozoospermic patients, although the precise mechanism of feed back still remains unknown.

Adult↗
PubMed1995

Prolongation of the QT interval observed in a Japanese patient with vivax malaria following treatment with halofantrine.

In 1992, some 90 countries or territories where 42% of the world's population resided were considered malarious and estimation of deaths from malaria worldwide per year were in the order of 1.4 of 2.8 million. The higher the number of Japanese who go abroad becomes (the total number in 1994 was 13,578,934: Records of Statistical Division of the Ministry of Justice), the greater is the risk of their contracting malaria. Indeed, the reported annual number of imported malaria cases increased to not less than 100. Now, malaria should first be presumed if a patient complains of a higher fever after a visit to a tropical country. And the importance of instituting prompt diagnosis and proper treatment should also be stressed. One of the antimalarials which has been highlighted for its effectiveness is halofantrine. This drug has been used for treatment of human malaria since 1984, and to date clinical trials have involved about 3.4 million patients in more than 30 countries (personal communication). Several patients successfully treated with halofantrine without any treatment failure have also been documented in Japan. However, in 1993, a clinical study involving 400 patients on the Thai-Burmese border revealed cardiac effects of antimalarial treatment with halofantrine, including one sudden death after the treatment. There have also been some spontaneous reports of serious ventricular dysrythmiasis with prolongation of the QT intervals, rarely associated with death. The pharmaceutical company producing Halfan has reported 8 cardiac arrests, leading to 6 deaths, when a higher dose than recommended was used, there was recent or concomitant treatment with mefloquine, there was pre-existing prolongation of the QT interval or the patient had a thiamine deficiency. Finally, the World Health Organization (WHO) announced a "drug alert" on halofantrine advising a change in recommendations for its use. In the present paper, we discuss the first Japanese vivax malaria patient whose QT interval was prolonged after treatment with halofantrine.

Adult↗
PubMed1995

Listener adaptive characteristics of vowel devoicing in Japanese dialogue.

Listener adapative characteristics of Japanese vowel devoicing were investigated by analyzing (i) dialogues between professional teachers and hearing-impaired (HI) or normal-hearing (NH) children, and (ii) speech samples read by the teachers as fast and clearly as possible (RD). The teachers reduced the devoicing rate and lengthened the moras more in the HI vs NH samples, and even more in the HI vs RD samples. A logistic regression analysis of the devoicing rate suggests that the speech rate dependency of the devoicing rate is different among the HI, NH, and RD samples. When moras are lengthened, the predicted devoicing rate decreases more for the HI vs NH samples, and even more in the HI vs RD samples, suggesting that not only rate-dependent adjustments but also rate-independent adjustments significantly affect devoicing reduction. These results suggest the following: (1) Professional teachers of hearing-impaired children reduce their devoicing not only by lengthening the interval of successive voicing/devoicing gestures, but also by resizing component gestures to some extent, probably to improve the listener's comprehension; (2) vowel devoicing should be represented in terms of parameters of speech motor control; (3) it may be possible to develop an optimized communication method for hearing-impaired children by simulating such listener-adaptive adjustments in speech production.

Child↗
PubMed1995

A rapid method for isolation of retinal pigment epithelial cells from rat eyeballs.

A new, simple method for isolating retinal pigment epithelial (RPE) cells from rat eyeballs was developed: incubation of the eyeballs in 0.1% proteinase K solution. This method yielded an average of 4 x 10(4) viable RPE cells from each Sprague-Dawley rat eyeball in 1 h. These RPE cells were hexagonal and had cytokeratin in their cytoplasm and numerous microvilli on their surface, similar to RPE cells evaluated in vivo. The results of this study thus show that our method for incubating eyeballs in proteinase K can provide good-quality RPE cells in sufficient quantities for study in a short time.

Animals↗
PubMed1995

Hypertrophic cranial pachymeningitis with spinal epidural granulomatous lesion.

A 67-year-old woman with a one-year history of tinnitus and headache had multiple cranial nerve palsies of V, VII, VIII, IX, X, XI and spastic paraparesis. She also had a secretory otitis media. Gd-DTPA-enhanced magnetic resonance imaging (MRI) revealed hypertrophy of the dura of the posterior fossa and spinal epidural mass which extended from C7 to T10. A biopsy of the epidural mass showed chronic granulomatous change. These lesions were completely cured with administration of antibiotics. We believe this case of double-lesion of hypertrophic cranial pachymeningitis and spinal epidural granulomatous lesion originated from a bacterial infection secondary to the secretory otitis media.

Aged↗