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Biomedical subjects

Y Fukuda

Publications and source records attributed to Y Fukuda.

At least 181 records · Page 10Linked to original sources
PubMed1999

Localization of FGFR-1 in axotomized and peripheral nerve transplanted ferret retina.

Retinal ganglion cells (RGCs) survive axotomy and regenerate their axons into the peripheral nerve graft in adult mammals. To understand the potential role of fibroblast growth factors (FGFs) in survival and regeneration of axotomized RGCs, we examined FGF receptor 1 (FGFR-1) localization in normal and PN grafted ferret retinas by immunohistochemistry in combination with retrograde labeling. Prominent expression of FGFR-1 was observed in outer plexiform layer and ganglion cell layer of normal ferret retina. In the ganglion cell layer, FGFR-1 immunoreactivity was detected in about 30% of RGCs, predominantly in large cells. In the PN grafted ferret retina, 90% of RGCs with regenerated axons expressed FGFR-1. Our findings suggest that FGFs may play an important role in the survival and axonal regeneration of RGCs of adult mammals.

Animals↗
PubMed1999

Frontal midline theta rhythms reflect alternative activation of prefrontal cortex and anterior cingulate cortex in humans.

Frontal midline theta rhythm (Fm theta) often appears on electroencephalogram (EEG) during consecutive mental tasks. To clarify the source of rhythmic activity, magnetoencephalogram (MEG) and EEG were simultaneously measured in six healthy volunteers during different mental tasks using whole head MEG system. MEG records were averaged every one cycle of Fm theta rhythms using individual positive peaks of Fm theta waves in Fz EEG as a trigger. Averaged theta components of MEG signals were analyzed with a multi-dipole model. Two sources were estimated to the regions both of the prefrontal-medial superficial cortex and anterior cingulate cortex (ACC). These regions were alternatively activated in about 40 to 120 degrees phase shift during one Fm theta cycle. From above results, we hypothesize that appearance of Fm theta during consecutive mental tasks reflects alternative activities of the medial prefrontal cortex and ACC.

Adult↗
PubMed1999

Thymidine phosphorylase expression is associated with both increase of intratumoral microvessels and decrease of apoptosis in human colorectal carcinomas.

Thymidine phosphorylase (dThdPase)/platelet-derived endothelial cell growth factor is expressed at higher levels in a variety of human carcinomas than it is in adjacent normal tissue. The higher expression is associated with an increase of intratumoral microvessel density (IMVD) and an unfavorable patient prognosis. We examined the role of dThdPase in apoptosis, cell proliferation, IMVD, and p53 expression in human colorectal carcinomas. dThdPase expression was noted in 13 of 36 (36.1%) Dukes' A and B carcinomas and in 13 of 28 (46.3%) Dukes' C and D carcinomas. At least 10 areas consisting of carcinoma cells with diffuse dThdPase expression from the 26 dThdPase-positive tumors (category I) and 10 areas without dThdPase expression from the 38 negative tumors (category II) were selected from each case. For stage A and B tumors, the mean IMVDs were 64.8 +/- 33.7 in category I and 33.2 +/- 12.6 in category II tumors, whereas for stage C and D tumors, the mean IMVDs were 77.6 +/- 27.2 in the category I and 34.7 +/- 14.0 in the category II tumors. The mean IMVD was significantly higher in category I than in category II tumors (P < 0.01). The mean apoptotic indices (AIs; percentage of apoptotic cells) were 2.7 +/- 1.7 in the category I and 5.4 +/- 2.2 in the category II carcinomas of stages A and B and 1.4 +/- 0.5 in category I and 5.3 +/- 2.3 in category II carcinomas of stages C and D, and the value of the mean AI was significantly lower in category I than in category II (P < 0.01), regardless of the Dukes' stage. AI and IMVD showed a significant inverse correlation (P < 0.001). There was no significant difference in the frequency of p53 expression between the two categories. These results indicated that dThdPase expression provides an advantage for tumor growth of human colonic carcinomas not only by increasing the intratumoral microvessels but also by attenuation of apoptosis, which might occur via a p53 gene-independent pathway.

Apoptosis↗
PubMed1999

Novel cyclopropapyrroloindole derivative (AT-3510) bearing methoxycarbonyl and trifluoromethyl groups.

The seco-Cl 3-methoxycarbonyl-2-trifluoromethylcyclopropapyrroloindole (MCTFCPI) derivatives dl- and/or (S)-10 carrying various acyl moieties at the N6-position were synthesized along with their prodrugs (S)-12, and their antitumor activity was evaluated. Among these derivatives, AT-3510 [(S)-12m], the novel prodrug MCTFCPI derivative carrying a 5-(7-methoxybenzofuran-2-ylcarbonyl)aminoindole-2-carb onyl group at the N6-position, was found to exhibit more excellent antitumor activity against human tumor xenografts than the clinical trial candidates carzelesin (6) and KW-2189 (7) and cisplatin.

Animals↗
PubMed1999

Comparative study of overlapping genes in the genomes of Mycoplasma genitalium and Mycoplasma pneumoniae.

Overlapping genes are defined, in this paper, as a pair of adjacent genes whose coding regions are partly overlapping. We systematically analyzed all overlapping genes in the genomes of two closely related species: Mycoplasma genitalium and Mycoplasma pneumoniae. Careful comparisons were made for homologous genes that are overlapped in one species but not in the other. This comparative analysis allows us to propose a model of how overlapping genes emerged in the course of evolution. It was found that overlapping genes were generated primarily due to the loss of a stop codon in either gene, in many cases, the absence of which resulted in elongation of the 3' end of the gene's coding region. More specifically, the loss of the stop codon took place as a result of the following events: deletion of the stop codon (64.4%), point mutation at the stop codon (4.4%), and frame shift at the end of the coding region (6.7%). Overlapping genes, in a sense, can be thought of as the results of evolutionary pressure to minimize genome size. However, our analysis indicates that many overlapping genes, at least in the genomes of M.genitalium and M.pneumoniae, are due to incidental elongation of the coding regions.

Genes, Bacterial↗
PubMed1999

Epitope mapping of monoclonal antibodies against N-domain of carcinoembryonic antigen.

Monoclonal antibodies (MoAbs) against N-domain of carcinoembryonic antigen (CEA), C249, K348, K1338, and K1444, that inhibit CEA-mediated cell adhesion, did not crossreact with nonspecific cross-reacting antigen (NCA). To determine amino acid sequences involved in the adhesion, epitopes of the MoAbs were mapped with recombinant NCAs carrying CEA-NCA chimeric N-domain. The data showed that the epitopes of C249, K1338, K1444 are located within the regions 1-32, 1-32, and 33-59 of CEA, respectively, and that two discrete regions 1-32 and 60-93 may be related to the epitope of K348. Comparison of amino acid sequences between CEA and NCA suggested that four residues (21, 27-29), eight residues (21, 27-29, 66, 78, 79, 89), and three residues (43, 44, 46) are important for recognition by C249 (or K1338), K348, and K1444, respectively. These residues seem to participate in the cell adhesion mediated by CEA.

Amino Acid Sequence↗
PubMed1999

Identification of a novel gene, MASL1, within an amplicon at 8p23.1 detected in malignant fibrous histiocytomas by comparative genomic hybridization.

We used comparative genomic hybridization to study malignant fibrous histiocytomas (MFHs) from 19 patients to detect changes in the copy number of DNA sequences, along entire chromosomes. Together with losses and gains in various chromosomal regions, distinct high-level amplifications were found at six loci (4q12-21, 8p21-pter, 8q24.1-qter, 9q12-13, 12p11.2-pter, and 15q11.2-15), suggesting that those regions may contain unknown (proto) oncogenes. We focused on the 8p amplicon, where detailed characterization allowed us to determine that the minimal common amplified region lay between markers D8S1819 and D8S550 at 8p23.1. A novel gene designated MASL1 (MFH-amplified sequences with leucine-rich tandem repeats 1) was isolated from within this narrowly defined region. Expression of the MASL1 gene was enhanced significantly in MFH tumors bearing the 8p amplicon. The primary structure of its deduced product revealed an ATP/GTP-binding site, three leucine zipper domains, and a leucine-rich tandem repeat, all of which are important structural or functional elements for interactions among proteins related to the cell cycle. These features suggest that overexpression of MASL1 might well be oncogenic with respect to MFH.

Adult↗
PubMed1999

Cloning and characterization of a novel Rab-family gene, Rab36, within the region at 22q11.2 that is homozygously deleted in malignant rhabdoid tumors.

Malignant rhabdoid tumors (MRTs) are rare, pediatric soft-tissue tumors. Homozygous deletions at chromosome 22q11.2 are a recurrent cytogenetic characteristic of MRTs, an indication that this locus may harbor one or more genes conferring tumor-suppressor activity. We constructed a deletion map of the relevant part of 22q11.2 from a panel of seven MRT cell lines, and isolated a novel gene from the center of the region. As it showed a high degree of sequence homology to genes of the Rab family, we designated it Rab36. The protein encoded by Rab36 was localized at the Golgi body. Sequencing of Rab36 cDNAs from three cell lines that retained at least one allele of this gene revealed no nonsense or frameshift mutations. Experiments to induce over-expression of Rab36 by transfection to an MRT cell line similarly failed to justify designation of this gene as a tumor suppressor that would contribute to tumorigenesis by a loss-of-function mechanism.

Amino Acid Sequence↗
PubMed1999

Humanization of a mouse neutralizing monoclonal antibody against tumor necrosis factor-alpha (TNF-alpha).

An anti-human tumor necrosis factor-alpha (TNF-alpha) monoclonal antibody, designated as 3B10, inhibits the biological activity of human TNF-alpha. In the present study, we constructed humanized version of the antibody by grafting its complementarity-determining regions (CDRs) onto a human antibody, HBS-1. Using a molecular model of mouse 3B10, framework residues affecting the CDR conformation were identified. Thus, these residues were also introduced into the framework together with the CDRs in a stepwise manner, depending on the degree of the possible importance of the residues. As a result, one humanized version (h3B10-9) which possesses nine mouse framework residues showed the same binding activity as that of the chimeric version. This humanized anti-TNF-alpha antibody is expected to be less immunogenic and thus more suitable for possible clinical use.

Amino Acid Sequence↗
PubMed1999

An analysis of subjective complaints in a population living in a methylmercury-polluted area.

The aim of this study is to document subjective complaints, to analyze the structure of a population living in a methylmercury-polluted area, and to investigate the relationship between the subjective complaints and methylmercury pollution. A total of 1304 adults in the polluted area, who were living in the methylmercury-polluted area near Minamata City in Kumamoto Prefecture, Japan, and 446 age-matched adults in a nonpolluted area were interviewed. Comparison of prevalence, factor analysis, and cluster analysis were conducted using data drawn from a questionnaire survey about 64 subjective complaints. The population in the polluted area had more various complaints than that living in the nonpolluted area. The factor analysis proposed four factors: nonspecific, sensory, arthritic, and muscular. Each of the four factor scores was significantly higher in the population in the polluted area. Subjects who had more complaints were classified into three clusters using cluster analysis. It is possible that not only neurological subjective complaints but also nonspecific complaints of the population in the polluted area might be influenced by past methylmercury exposure.

Adult↗
PubMed1999

Recovery of visual behaviors in adult hamsters with the peripheral nerve graft to the sectioned optic nerve.

In adult hamsters, the autologous peripheral nerve (PN) was grafted to the sectioned optic nerve to make a bridge to the superior colliculus (SC). Three behavioral tasks were used to test functional recovery of the restored retinocollicular pathway. First, change of spontaneous ambulating activity to a decrease in environmental luminance was examined in an open field. PN-grafted hamsters showed a significant increase to 186% in ambulating activity just after light off, though it was lower than that in normal hamsters (489%). Second, a classical conditioning of total body movements was tested using an increase in luminance as a conditioned stimulus (CS) paired with foot shocks. In normal hamsters the magnitude of movements during CS increased in the acquisition period and then decreased in the extinction period in both the second and the third sessions, while the magnitude remained unchanged in a blind control. PN-grafted hamsters showed an increase in the magnitude only in the third session, although it was statistically barely significant (P = 0.0619). Following section of the grafted nerve, the conditioned response disappeared completely. And third, a shuttle-box avoidance task was examined using a flickering light as CS. Normal hamsters showed improved avoidance scores, while blind controls did not. PN-grafted hamsters showed a slight increase in the score, which was similar to that in the one-eyed control. Anterogradely transported labeling of WGA-HRP, injected into the vitreous body of the grafted eye, was observed in the graft and the superficial layers of SC. These results confirm and extend our previous finding that PN-grafted hamsters can restore some visual function and further suggest that the extent of recovered visual function is as good as in one-eyed animals.

Animals↗
PubMed1999

Environmental light enhances survival and axonal regeneration of axotomized retinal ganglion cells in adult cats.

A segment of peripheral nerve was transplanted to the cut stump of the optic nerve to facilitate axonal regeneration of retinal ganglion cells (RGCs) in adult cats. The cats were reared under different light environment: 12 h light-12 h darkness, additional flash light under conventional light cycle, or 24 h darkness. After 60 days, the density and morphology of RGCs with regenerated axons were examined with retrograde labeling by fluoro-ruby and intracellular injections of Lucifer Yellow. In the retina of cats reared in darkness, densities of RGCs with regenerated axons were 11-42% of those in the retina of cats reared under conventional light and dark cycle. More than half of the labeled RGCs were degenerative in the retina of cats reared in darkness, while most RGCs were normal under conventional environment or flash light. We conclude that environmental light is essential for the survival and axonal regeneration of axotomized RGCs.

Animals↗
PubMed1999

Z-350, a new chimera compound possessing alpha1-adrenoceptor antagonistic and steroid 5alpha-reductase inhibitory actions.

The effects of Z-350, (S)-4-[3-(4-{1-(4-methyl-phenyl)-3-[4-(2-methoxyphenyl)piperazine-1-yl]propoxy} benzoyl)indole-1-yl]butyric acid hydrochloride, a newly synthesized compound possessing alpha-adrenoceptor antagonistic and steroid 5alpha-reductase inhibitory actions, were studied in vitro. In functional experiments, Z-350 shifted the concentration/response curve for the phenylephrine-induced contraction of rabbit prostate, urethra and aorta to the right with pA2 values of 8.04, 7.57 and 7.13, respectively. The binding affinity of Z-350 for alpha1-adrenoceptors in rabbit prostate, urethra and aorta were estimated by the displacement of [3H]prazosin. The pKi values for this action of Z-350 were 7.53, 7.95 and 7.62 for the prostate, urethra and aorta, respectively. alpha1-Adrenoceptor subtype selectivities were studied in the submaxillary gland (r(1A) and liver (alpha1B) of rat. Z-350 inhibited the specific binding of [3H]prazosin to alpha1A and (alpha1B-adrenoceptors with pKi values of 7.82 and 7.29, respectively. Z-350 inhibited rat prostatic steroid 5alpha-reductase non-competitively with a pIC50 of 8.42. These results indicate that Z-350 is a alpha1-adrenoceptor antagonist and is a steroid 5alpha-reductase inhibitor. It is expected that Z-350 will be a candidate drug for the treatment of benign prostatic hyperplasia.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
PubMed1999

Receptive-field properties of adult cat's retinal ganglion cells with regenerated axons.

Receptive-field properties of retinal ganglion cells (RGCs) that had regenerated their axons were studied by recording single-unit activity from strands teased from peripheral nerve (PN) grafts apposed to the cut optic nerve in adult cats. Of the 286 visually responsive units recorded from PN grafts in 20 cats, 49.7% were classified, according to their receptive-field properties, as Y-cells, 39.5% as X-cells, 6.6% as W-cells, and 4.2% were unclassified. The predominant representation of Y-cells is consistent with a corresponding morphological study (Watanabe et al. 1993a), which identified alpha-cells as the RGC type with the largest proportion of regenerating axons. Among the X-cells, we only found ON-center types, whereas both ON-center and OFF-center Y-cells were found. As in intact retinas, the receptive-field center sizes of Y-cells and W-cells were larger than those of X-cells at corresponding displacements from the area centralis. Within the 10 degrees surrounding the area centralis, the receptive fields of X-cells with regenerated axons were larger than those in intact retinas, suggesting that some rearrangement of retinal circuitry occurred as a consequence of degeneration and regeneration. Receptive-field center responses of Y-, X-, and W-type units with regenerated axons were similar to those found in intact retinas, but the level of spontaneous activity of Y- and X-type units was, in general, less than that of intact RGCs. Receptive-field surrounds were weak or not detected in more than half of the visually responsive RGCs with regenerated axons.

Animals↗