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Biomedical subjects

Y Kishimoto

Publications and source records attributed to Y Kishimoto.

At least 19 recordsLinked to original sources
PubMed1992

Binding and transport of gangliosides by prosaposin.

Prosaposin, the precursor of saposins A, B, C, and D, which activate lysosomal hydrolysis of sphingolipids, exists in various tissues and body fluids and is especially abundant in the nervous system. Prosaposin and saposins A,B, C, and D formed stable complexes with 13 different gangliosides as measured by an assay using column chromatography. Gangliosides of the gangliotetraose type (a series) were bound with high affinity, whereas b series gangliosides, O-acetylated gangliosides, and gangliosides with shorter carbohydrate chains, were bound with lower affinity. Prosaposin and saposins transferred gangliosides from donor liposomes to erythrocyte ghost membranes. Prosaposin also stimulated ganglioside GM1 beta-galactosidase more than mature saposins. Prosaposin exists as a secretory protein and as an integral membrane protein, and we propose that prosaposin is active as a ganglioside binding and transport protein in vivo.

Biological Transport↗
PubMed1992

Aberrations of the p53 tumor suppressor gene in human non-small cell carcinomas of the lung.

Aberrations of the p53 gene in 115 surgical specimens of non-small cell carcinomas of the lung were examined by single-strand conformation polymorphism analysis of polymerase chain reaction products. Structural abnormalities of the p53 gene were observed in 60 tumors (52%), i.e., 8 of 14 large cell carcinomas, 24 of 58 adenocarcinomas, 25 of 37 squamous cell carcinomas, and 3 of 6 adenosquamous carcinomas. Direct sequencing of abnormal DNA fragments revealed 45 single-base substitutions, 9 deletions or insertion of a short nucleotide sequence, and 3 two-base substitutions in 57 tumors. In the other 3 tumors, loss of one of the p53 alleles was observed, with no mutation in the other allele. Allelic loss of the p53 gene was observed in 14 of 43 informative cases (33%), and in 11 of the 14 cases the remaining allele was mutated. The aberrations of the p53 gene were not limited to a particular histological type or clinical stage. Their high frequency suggests that they were involved in the genesis of non-small cell carcinomas of the lung. The mutation frequency (46%) of the p53 gene in tumors carrying mutated ras genes was essentially the same as the overall frequency in lung cancers, suggesting that accumulation of mutations in these two genes in a tumor is a random phenomenon.

Base Sequence↗
PubMed1992

The medial dorsal nucleus is one of the thalamic relays of the cerebellocerebral responses to the frontal association cortex in the monkey: horseradish peroxidase and fluorescent dye double staining study.

To reveal the thalamic relay nucleus of the cerebellocerebral responses in the frontal association cortex, simultaneous labeling of the cerebellothalamic (C-T) terminals and the thalamocortical (T-Cx) neurons was performed in three monkeys. Horseradish peroxidase (HRP) was injected into the deep cerebellar nuclei and small doses of HRP or fluorescent dye were injected into the prefrontal cortex. The distribution of anterogradely labeled C-T terminals and retrogradely labeled T-Cx neurons was examined in the same sections. In addition to being distributed in the ventral thalamic nuclei and nucleus X, as previously reported, anterogradely labeled terminals were distributed in the ventrolateral part of the medial dorsal (MD) nucleus where retrogradely labeled thalamo-frontal projection neurons were localized. This study revealed that the ventrolateral parts of the MD together (MDmf, MDpc and MDdc) form one of the thalamic relays of the cerebelloprefrontal responses.

Animals↗
PubMed1992

Detection of a common mutation of the catalase gene in Japanese acatalasemic patients.

Acatalasemia was one of the earliest described genetic enzyme defects. In 1990, a causal point mutation (a splicing mutation) was first reported in a Japanese patient with acatalasemia. In the present study, the polymerase chain reaction and single-strand conformation polymorphism analysis were used to determine whether the same point mutation was present in unrelated Japanese patients. The subjects studied were the previously examined acatalasemic female, her brother, who is hypocatalasemic, and two other unrelated acatalasemic patients. A single G to A point mutation at the fifth position of intron 4, identical to that previously found, was present in all the studied patients. This finding strongly suggests that only a single mutated allele has spread in the Japanese population.

Acatalasia↗
PubMed1992

Distribution of saposins (sphingolipid activator proteins) in tissues of lysosomal storage disease patients.

Saposins are a group of small glycoproteins derived from a single precursor protein, prosaposin. Each of the four saposins are involved in lysosomal hydrolysis of various sphingolipids. Our recent investigations have shown that saposins accumulate in tissues of several lysosomal storage diseases patients, including those with Tay-Sachs disease and Gaucher disease. To obtain insight into the mechanism of accumulation and its pathological role, the subcellular distribution of saposins in brain from Tay-Sachs disease and in spleen of Gaucher disease were compared with that of GM2 ganglioside and glucocerebroside, respectively. In both Tay-Sachs brain and Gaucher spleen, saposins were found predominantly in light-density fractions while most of the GM2 ganglioside and glucocerebroside, respectively, were found in heavy-density fractions. These studies indicate that saposins that accumulate in these pathological tissues are not tightly associated with GM2 ganglioside or glucocerebroside.

Brain↗
PubMed1992

Acute myelomonocytic leukemia with marrow eosinophilia showing 5q- and 16q22 mosaicism.

We report an 82-year-old Japanese female with acute myelomonocytic leukemia with dysplastic marrow eosinophilia (FAB M4Eo) exhibiting a partial deletion of the long arm of chromosome 5, del(5)(q13q31) and a derivative chromosome 16 with a breakpoint at band 16q22, in addition to 5q-. The patient had a history of a preleukemic phase for several months with marked dysplasia in trilineage marrow cells, in addition to leukemic features compatible with M4Eo. These findings strongly suggested that the leukemic cells in this case were derived from a preleukemic clone with a del(5q).

Aged↗
PubMed1992

Morphological features of cat thalamo-parietal projection fibers investigated by PHA-L immunohistochemistry and electron microscopy.

Thalamo-parietal fibers originating from the ventroanterior-ventrolateral (VA-VL) complex in the cat were labeled with Phaseolus vulgaris leucoagglutinin (PHA-L) and examined by light and electron microscopy. PHA-L (2.5% aqueous solution) was injected iontophoretically through micropipets with anodal current pulses into the VA-VL complex. PHA-L-labeled terminals were distributed in the lateral and the suprasylvian gyri in the superficial and deep cortical layers. In layer I, horizontal varicose fibers and terminals were conspicuous in the upper one-third and were widely distributed. In the deeper cortical layers (layers III-V), varicose fibers and terminals were detected in moderate numbers. Electron microscopic examination revealed that the labeled terminals formed asymmetrical synapses on the dendritic spines of spiny neurons. These morphological findings appeared to be consistent with our previous intracellular recordings in this cortex.

Animals↗
PubMed1992

Production and characterization of a monoclonal antibody to human saposin C.

A murine IgG1 monoclonal antibody, termed 68-12, was produced against purified human saposin C. Immunoprecipitation and binding analysis indicated that the antibody reacted only with saposin C. Dot blotting and Western analysis demonstrated that antibody 68-12 also reacted with prosaposin and a higher molecular weight protein(s) in murine spleen and cerebral grey matter. Solid phase competitive radioimmunoassay against 125I labeled saposin C (0.25 micrograms/ml) showed no cross reactivity for saposin A, B and D up to 15 micrograms/ml. At a concentration of 50 micrograms/ml saposin A, B and D cross reacted 21, 1.5, and 49% respectively. Monoclonal antibody 68-12 appears to have potential utility in the purification, detection and quantitation of human saposin C and its precursor.

Animals↗
PubMed1992

F-SSCP: fluorescence-based polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP) analysis.

A fluorescence-based method for polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP) analysis, F-SSCP, was developed in which the target sequence is amplified by the PCR using fluorescent primers. The amplified products are then heat-denatured and applied to a water-jacket controlled gel in an automated DNA sequencer. The separated strands are detected as laser-excited fluorescence at the bottom of the gel, and mutations are detected as shifts in the position of the peaks in the fluorogram. The system does not involve radioactivity, and the conditions of electrophoresis are more strictly controlled than in the previous system, which relied on ambient air-cooling to maintain the gel at a constant temperature. The nature of the output data allows direct quantitative interpretation, and so the relative abundance of each allele in a mixture of two or more alleles can easily be estimated. The application of F-SSCP for detection of mutations and loss of heterozygosities of p53 in tumor tissues is reported.

Base Sequence↗
PubMed1992

Detection of DNA aberrations in human cancers by single-strand conformation polymorphism analysis of polymerase chain reaction products.

We have developed a simple, sensitive method, single-strand conformation polymorphism (SSCP) analysis, to detect a single nucleotide substitution in a DNA fragment amplified and labeled by the polymerase chain reaction (PCR). Mobility shift of single-stranded DNAs due to their specific conformations on non-denaturing polyacrylamide gel electrophoresis can reveal DNA aberrations. By the PCR-SSCP analysis of DNAs from surgical specimens of human cancers, mutated ras genes (17%) and aberrations of tumor suppressor p53 gene (53%) including loss of one of the two alleles and a mutation in the remaining allele were detected in lung carcinomas and aberrations of both of the p53 and retinoblastoma (RB) genes were detected exclusively in advanced hepatocellular carcinomas.

Carcinoma, Hepatocellular↗
PubMed1992

Fetal and neonatal excretion of free and conjugated ritodrine.

The ability of the human fetus and neonate to conjugate and excrete ritodrine, a beta 2-sympathomimetic drug, was investigated. Free and conjugated ritodrine concentrations in the plasma, amniotic fluid and urine were measured in 11 mother-infant pairs, to whom intravenous ritodrine had been administered before elective cesarean section at term. Ritodrine was determined by HPLC with electrochemical detection. At delivery, conjugated ritodrine values were significantly higher than those for the free form in maternal and fetal plasma. There were significant positive correlations between the concentrations in the maternal and umbilical vein plasma for both free and conjugated ritodrine. In the amniotic fluid, the total ritodrine concentrations were much higher than those in the fetal plasma, the conjugated form accounting for 90.2% of the total. Furthermore, the percentages of conjugated ritodrine in the amniotic fluid and neonatal urine were significantly higher than the percentage in the maternal urine on the day of birth. In the neonatal urine, the concentrations of free and conjugated ritodrine decreased rapidly after birth as did those in the maternal urine, on day 3 postpartum being less than 2% of the values on the day of parturition. These results indicate that the fetus at term is capable of forming conjugated metabolites of ritodrine and of excreting free and conjugated ritodrine in its urine.

Amniotic Fluid↗
PubMed1992

[Construction of a multiple mood scale].

A self-report instrument to measure multiple mood states was constructed. Six hundred and forty-eight Japanese affect adjectives were collected and divided into two lists. Japanese undergraduates totaling 1,254 rated each adjective in the list on a 4-point intensity scale to assess their momentary mood states. Factor analyses revealed 131 items with high loading on extracted major factors. The new list of these 131 items was rated three times by undergraduates totaling 1,768 and was factor analysed. Throughout the factor analyses, eight factors emerged with consistent reliability. Finally, 80 items highly loaded on these factors were selected to construct eight 10-item mood scales. These scales were called Depression (Anxiety), Hostility, Boredom, Liveliness, Well Being, Friendliness, Concentration and Startle. The scales were shown to be internally consistent. A comparison of these scales with the English mood scales was presented.

Adolescent↗
PubMed1992

Ultrastructural analysis of platelet-like particles from a human megakaryocytic leukemia cell line (CMK 11-5).

Ultrastructural observations were performed to further characterize the human megakaryocytic leukemia cell line, CMK, and its subclone, CMK11-5. We found that particles derived from CMK11-5 cells had cytoplasmic projections and no nucleus, and that some particles contained alpha granules. Incubation with ADP induced fibrinogen receptors on the surface of these particles. Furthermore, the particles had glycoprotein Ib antigen on their surfaces, and attached nonreversibly to rabbit aortic subendothelium, showing associated morphological changes similar to those observed in normal platelets. CMK and CMK11-5 are the first megakaryocytic cell lines that have been found to release particles that have some of the same functions as normal platelets. In particular, CMK11-5 seems to be a useful model for studying megakaryocyte function.

Blood Platelets↗
PubMed1992

Saposins: structure, function, distribution, and molecular genetics.

Saposins A, B, C, and D are small heat-stable glycoproteins derived from a common precursor protein, prosaposin. These mature saposins, as well as prosaposin, activate several lysosomal hydrolases involved in the metabolism of various sphingolipids. All four saposins are structurally similar to one another including placement of six cysteines, a glycosylation site, and conserved prolines in identical positions. In spite of the structural similarities, the specificity and mode of activation of sphingolipid hydrolases differs among individual saposins. Saposins appear to be lysosomal proteins, exerting their action upon lysosomal hydrolases. Prosaposin is a 70 kDa glycoprotein containing four domains, one for each saposin, placed in tandem. Prosaposin is proteolytically processed to saposins A, B, C and D, apparently within lysosomes. However, prosaposin also exists as an integral membrane protein not destined for lysosomal entry and exists uncleaved in many biological fluids such as seminal plasma, human milk, and cerebrospinal fluid, where it appears to have a different function. The physiological significance of saposins is underlined by their accumulation in tissues of lysosomal storage disease patients and the occurrence of sphingolipidosis due to mutations in the prosaposin gene. This review presents an overview of the occurrence, structure and function of these saposin proteins.

Animals↗
PubMed1991

Human placental sialidase complex: characterization of the 60 kDa protein that cross-reacts with anti-saposin antibodies.

Sialidase isolated from human placenta is associated with several proteins including acid beta-galactosidase, carboxypeptidase, N-acetyl-alpha-galactosaminidase, and others. These proteins are thought to form an aggregated complex during isolation of sialidase. One of the proteins of 60 kDa was recently identified by Potier et al. (Biochem. Biophys. Res. Comm. 173, 449-456, 1990) as a sialidase protein: this protein also cross-reacted with anti-prosaposin antibodies. We have isolated this protein and from the following evidence identified it as a heavy chain component of immunoglobulin G and not sialidase or a derivative of prosaposin. On gel filtration HPLC, sialidase activity and the 60 kDa protein were clearly separated from one another. The 60 kDa protein cross-reacted not only with antibodies raised against human saposins A, C, and D, but also with second antibody (goat anti-rabbit immunoglobulin G antibody) alone. This 60 kDa protein strongly cross-reacted with anti-human immunoglobulin G antibodies. The sequence of the initial 15 amino acids from the N-terminus of the 60 kDa protein was identical to the sequence of an immunoglobulin G heavy chain protein Tie (gamma 1).

Amino Acid Sequence↗
PubMed1991

Binding specificity of D-mannose 6-phosphate receptor of rabbit alveolar macrophages.

The existence of terminal D-mannosyl 6-phosphate groups (Man-6-P) was required (for an inhibitor) to exert a strong inhibitory potency against the binding of bovine serum albumin (BSA) conjugated with 17 molecules of penta-D-mannose 6-phosphate [(M5P)17-BSA] to the Man-6-P receptor in rabbit alveolar macrophages. In addition, the underlying oligosaccharide structures, such as linkage mode between the nonreducing sugar group and the penultimate sugar residue, and the length of sugar chain also affected the inhibitory potency in this system. In general, the oligosaccharides with an alpha-(1----2)-linked Man-6-P unit gave stronger inhibitory potencies than those with an alpha-(1----3)- or alpha-(1----6)-linked Man-6-P unit. Trisaccharides containing a terminal Man-6-P group were more potent inhibitors than disaccharides. A synthetic, branched, and divalent ligand, which does not have a penultimate sugar residue, gave about the same level of inhibitory potency as Man-6-P itself. The "cluster effect" was observed in this system, i.e., as the number of Man-6-P units conjugated to BSA [(Man-6-P)5,5,8, and 46-BSA] increased, the stronger inhibitory potencies were observed with decreasing I50 values of 1.93, 1.36, and 0.0345 microM, respectively. Synthetic divalent oligosaccharides also showed higher inhibitory potencies than the corresponding monovalent oligosaccharides.

Animals↗
PubMed1991

Saposin proteins: structure, function, and role in human lysosomal storage disorders.

Saposins are sphingolipid activator proteins, four of which are derived from a single precursor, prosaposin, by proteolytic processing. These small heat-stable glycoproteins (12-14 kDa) are required for the lysosomal hydrolysis of a variety of sphingolipids. Characterization of these four activator proteins, two of which were recently discovered, and their importance in human health and disease are reviewed in this article.

Amino Acid Sequence↗