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Biomedical subjects

Y Tsukamoto

Publications and source records attributed to Y Tsukamoto.

At least 91 records · Page 5Linked to original sources
PubMed1998

New N-glycans in horseradish peroxidase.

We describe here the structures of several new N-glycan oligosaccharides from horseradish peroxidase (HRP). Glycopeptides from HRP were digested with glycoamidase A (from sweet almond) to release the N-glycans. The oligosaccharides were reductively aminated with 2-aminopyridine, and separated by high-performance liquid chromatography on octadecylsilyl- and amide-silica columns for two-dimensional mapping (Tomiya et al., Anal. Biochem. 171, 73-90, 1988). The N-glycans were also analyzed by electrospray ionization mass spectrometry. Two different lots of HRP showed a considerable difference in their N-glycan composition.

Amidohydrolases↗
PubMed1998

Adhesive activity of gicerin, a cell-adhesion molecule, in kidneys and nephroblastomas of chickens.

Gicerin, a cell-adhesion molecule belonging to the immunoglobulin superfamily, has both homophilic and heterophilic binding activities to neurite outgrowth factor, an extracellular matrix molecule in the laminin family. Gicerin is thought to play a role in the normal development of chicken kidney, because it is expressed abundantly in the embryonic organ and only slightly in the mature organ. In this study, we have examined the adhesive activity of gicerin in the kidney to characterize its function in organogenesis. We have also examined the function of gicerin in chicken nephroblastomas ("embryonic nephromas"), which show various structures resembling those in embryonic kidneys. Immunohistochemically, the expression patterns of gicerin and neurite outgrowth factor in nephroblastomas are similar to those of embryonic kidneys. Cell-aggregation assays have shown that primary culture cells from both embryonic kidneys and nephroblastomas have strong aggregation activities, and that each aggregation is partially inhibited by gicerin antibody. In contrast, cells from adult kidney exhibit weak aggregation activity that is not inhibited by the antibody. In addition, ligand blot analysis has revealed that gicerins in embryonic kidney and nephroblastoma bind to purified neurite outgrowth factor, whereas extracts from adult kidney show no positive reaction. These findings suggest that the homophilic and heterophilic adhesive activities of gicerin are involved in the formation of both normal kidney and nephroblastoma.

Animals↗
PubMed1998

Influence of progesterone and oestrogen on growth and morphology of a transplantable rat uterine smooth muscle tumour (SMT-Y).

Tumours of uterine smooth muscle are poorly understood neoplasms in which the effects of steroid sex hormones are complex. The influence of progesterone and oestrogen on a transplantable rat uterine smooth muscle tumour line (SMT-Y) was investigated. Female F344 rats given subcutaneous transplants of tumour fragments developed tumours, 1.5-2 cm in diameter, and were then treated with progesterone (10 mg/rat) or 17 beta-oestradiol (50 mg/rat). Tumours in treated groups were compared with those in untreated controls. During a 9-week observation period after treatment, progesterone promoted tumour growth from 4 weeks, with increased numbers of proliferating cells. In contrast, oestradiol inhibited tumour growth from 6 weeks; the degraded tumours, consisting mainly of vacuolated neoplastic cells, had decreased numbers of proliferating cells and increased numbers of apoptotic cells, demonstrable by in-situ terminal deoxyribonucleotide transferase (TdT)-mediated dUTP nick labelling. Immunohistochemically, tumours in control and progesterone groups were labelled positively for alpha-smooth muscle actin (SMA) and desmin but not for vimentin, whereas the degraded tumours in the oestradiol group had reduced reactivity for SMA and desmin but an increased reactivity for vimentin. These results indicate that progesterone may act as a promoter for uterine smooth muscle tumour growth by stimulating mitotic activity, whereas oestrogen may have suppressive effects on tumour growth, accompanied by morphological changes.

Animals↗
PubMed1998

Functional architecture of primate cone and rod axons.

The cone axon is nearly four times thicker than the rod axon (1.6 vs 0.45 microns diameter). To assess how signal transfer and integration at the terminal depend on cable dimensions, a transducer (cone = ohmic conductance, rod = current source) coupled via passive cable to a sphere with a chloride conductance (representing GABAA receptor) was modelled. For a small signal in peripheral cone with a short axon, steady photosignal transfers independently of axon diameter despite a significant chloride conductance at the cone terminal. Temporally varying photosignal also transfers independently of axon diameter up to 20 Hz and is attenuated only 20% at 50 Hz. Thus, to accomplish the basic electrical functions of a peripheral cone, a thin axon would suffice. For a foveal cone with a long axon steady photosignal transfers independently of axon diameter, but temporally varying photosignal is attenuated 5-fold at 50 Hz for a thick axon and 10-fold for a thin axon. This might contribute to the lower sensitivity of central retina to high temporal frequencies. The cone axon contains 14-fold more microtubules than the rod axon, and its terminal contains at least 20-fold more ribbon synapses than the rod's. Since ribbon synapses sustain high rates of exocytosis, the additional microtubules (which require a thicker axon) may be needed to support a greater flux of synaptic vesicle components.

Animals↗
PubMed1998

Neurite promotion from ciliary ganglion neurons by gicerin.

Gicerin is a cell adhesion molecule of an immunoglobulin superfamily member and transiently expressed on the surface of neurons such as retinal ganglion cells during synaptogenesis. Gicerin is a receptor for NOF (neurite outgrowth factor) that belongs to the laminin family, and mediates neurite extension induced by NOF. As we have reported, gicerin also exhibits homophilic cell adhesion activity, we compared the patterns of extending neurites induced by homophilic and heterophilic cell adhesion activities of gicerin using ciliary ganglion (CG) neurons. CG neurons expressed gicerin and extended neurites on a feeder layer of gicerin-transfected cells, suggesting a neurite extension by gicerin-gicerin (homophilic) interaction. We found that CG neurons cultured on gicerin-transfected cells extended slightly branched neurites, while those cultured on NOF-coated substratum extended many long branched neurites. It is suggested that neurites induced by homophilic or heterophilic cell adhesion activities of gicerin differ in the length and branching.

Animals↗
PubMed1998

N-glycan structures of a recombinant mouse soluble Fcgamma receptor II.

N-glycans of a recombinant mouse soluble Fcgamma receptor II (sFcgammaRII) expressed in baby hamster kidney cells were released from glycopeptides by digestion with glycoamidase A (from sweet almond), and the reducing ends of the oligosaccharides were reductively aminated with 2-aminopyridine. The derivatized N-glycans were separated and structurally identified by a three-dimensional high-performance liquid chromatography (HPLC) mapping technique on three kinds of HPLC columns [Takahashi, et al. (1995) Anal. Biochem. 226:139-46]. Eighteen different major N-glycan structures were identified, of which six were neutral (45%), five mono-sialyl (49%), one di-sialyl (4.6%), five tri-sialyl (1.1%), and one tetra-sialyl (0.3%). All N-glycan structures determined were complex type with fucosylation at the N-acetylglucosamine residue of the reducing end, and N-acetylneuraminic acid, when present, was alpha-(2,3)-linked. The existence of a unique structure containing both N-acetylgalactosamine and alpha-(2,3)-N-acetylneuraminic acid residues at the reducing ends, as below, was confirmed by MALDI-TOF mass spectrometry. Carbohydrate sequence [see text]

Animals↗
PubMed1998

Effect of herbal therapy on herpes labialis and herpes genitalis.

Administration of hot water extracts of six herbs to four patients with recurrent herpes labialis led to prompt crusting over and complete recovery within a few days. Similar treatment for one female patient who had been suffering from recurrent genital herpes resolved the associated pain dramatically. In all cases mentioned, symptoms disappeared much more quickly than with previous outbreaks when herb extracts were not administered.

Adult↗
PubMed1998

Double-strand break repair mediated by DNA end-joining.

DNA double-strand breaks formed by ionizing irradiation or other stresses are repaired by homologous recombination or DNA end-joining. This review focuses on the mechanism of double-strand break repair mediated by DNA end-joining, in which many factors have recently been identified. After DNA double-strand breakage, DNA end-joining takes place between the DNA ends that have nonhomologous sequences or very short regions ofhomology. The broken DNA is repaired if the DNA end-joining occurs in the same molecule, while it causes chromosome aberrations such as deletions, insertions, translocations and inversions if it occurs between different molecules. Rad50 and its relatives, Ku-proteins, DNA ligase VI and silencing factors, are involved in DNA end-joining in yeast and mammalian cells. These findings led us to propose a model in which the formation of a heterochromatin-like complex at broken ends is an important element in DNA end-joining.

Animals↗
PubMed1998

Effect of probucol on serum lipoprotein and apoprotein profiles in renal transplant patients.

The therapeutic effect of probucol on hypercholesterolemia in cyclosporine A (CyA)-treated renal transplant patients was prospectively studied. Twelve posttransplantation patients aged 34.2+/-2.5 years with serum total cholesterol (t-CHL) of 250 mg/dL or greater, whose serum creatinine was 2.9 mg/dL or less, and who had no diabetes mellitus or hypoproteinemia, were treated with probucol, 250 mg twice daily for 3 months. Seventeen age-matched (36.8+/-1.6 years) normal volunteers served as control. Blood was drawn after at least a 12-hour fast to measure lipids in serum and lipoprotein fractions, apoproteins (apo), lipoprotein fractions, lethicin cholesterol acyl transferase (LCAT), free fatty acids (FFA), and CHL-ester. Serum t-CHL, triglycerides (TG), and phospholipids (PL) in posttransplantation patients before treatment were significantly higher compared with normal control subjects. Very-low-density lipoprotein (VLDL) and low-density lipoprotein (LDL) fractions in these patients were significantly expanded. The pretreatment levels of serum apo AII, B, CII, and CIII were significantly increased compared with those of normal controls. After treatment with probucol, serum t-CHL, LDL-CHL, high-density lipoprotein (HDL)-CHL, PL, LDL-PL, and apo AI were significantly decreased, and CHL-ester significantly increased compared with the pretreatment levels. These data suggest that although probucol causes a decrease in HDL-CHL, it may act anti-atherogenically by modulating HDL metabolism and stimulating reverse transfer of CHL from peripheral tissue.

Adult↗
PubMed1998

Vitamin D receptor gene polymorphisms affect secondary hyperparathyroidism in hemodialyzed patients.

Adynamic bone disease unrelated to aluminum deposition, with low parathyroid hormone (PTH) levels, has increased in patients with end-stage renal failure. Some patients present with severe secondary hyperparathyroidism despite calcitriol administration and phosphate restriction. Because therapeutic and environmental factors are now similar among hemodialyzed patients, the variable incidence of secondary hyperparathyroidism may be caused by genetic heterogeneity. To examine this possibility, we analyzed restriction fragment length polymorphisms of the vitamin D receptor (VDR) gene in 877 Japanese hemodialysis patients. VDR allelic polymorphism was determined by the method of Morrison et al. Polymerase chain reaction (PCR) amplification and a BsmI endonuclease restriction site at the 5' end of the VDR gene defined BB (absence of restriction site on both alleles), Bb (heterozygous), or bb (restriction site on both alleles). The mean serum PTH level was lower in BB patients (86 +/- 102 pg/mL) than in bb patients (148 +/- 217 pg/mL; P < 0.05). The serum osteocalcin level was also lower in BB than in bb patients (P < 0.05). If results were re-analyzed excluding patients with a history of dialysis exceeding 10 years or those with non-insulin-dependent diabetes mellitus (NIDDM) or who had undergone parathyroidectomy, the differences in serum PTH levels were greater. However, there was no significant difference in serum PTH levels among the VDR genotypes, only for patients with NIDDM. The present study shows that patients with the b allele for the VDR gene have more severe secondary hyperparathyroidism than patients without the b allele. However, NIDDM or a long history of hemodialysis has a stronger power to influence PTH secretion.

Adult↗
PubMed1998

Spectroscopic studies on the interaction of pradimicin BMY-28864 with mannose derivatives.

Pradimicin BMY-28864 (Pm) is an antibiotic effective against yeasts and fungi, and is known to bind mannose in the presence of Ca2+. We examined spectroscopically the mode of interactions among Pm, Ca2+, and glycosides of mannose and mannose oligosaccharides (Manalpha1-OMe, Manalpha1-2Manalpha1-OMe, Manalpha1-3Manalpha1-OMe, Manalpha1-4Manalpha1-OMe, Manalpha1-6Manalpha1-OMe, Manalpha1-6(Manalpha1-3)Manalpha1-OMe, and Man9GlcNAc2-Asn, a high mannose type N-linked oligosaccharide). All the mannosides interacted with Pm in the presence of Ca2+ and caused absorbance changes. The absorbance changes occurred nonlinearly with respect to the carbohydrate concentration and do not follow a simple binding isotherm equation, suggesting a unique multistep interaction mode. The concentrations that induced half the maximum absorbance change were approximately 10 mM for the mono- and di-mannosides and around 1.5 mM for the trimannoside and Man9GlcNAc2-Asn. Methyl alpha-D-glucopyranoside, methyl alpha-D-galactopyranoside, lactose, and myo-inositol did not affect the absorbance of Pm up to 50 mM. Ca2+ alone also influenced the absorbance of Pm. The absorbance between 200 and 700 nm decreased hypochromically when Ca2+ was added. The concentration that gave half the maximum absorbance decrease caused by Ca2+was around 15 microM. Our results suggest that two Pm molecules bind one C a2+, and each Pm binds two mannosyl residues.

Anthracyclines↗
PubMed1998

Identification of the gene loci that predispose to rheumatoid arthritis.

We have searched the human genome for genes that predispose to rheumatoid arthritis (RA) using fluorescence-based microsatellite marker analysis and affected sib-pair linkage study. A panel of 41 Japanese families, each with at least two affected siblings, was typed for genome-wide 358 polymorphic microsatellite marker loci. Markers were amplified by the PCR using fluorescence-tagged primers and sized based on the difference of CA repeats on DNA. Linkage analysis was made using maximum lod score (MLS). The MLS for D1S214 and D8S556 was 3.27 and 3.33, while the MLS for the HLA-DRB1 region was <3.0. According to detailed analysis by single-point analysis using MAPMAKER/SIBS, the MLS for D1S253 and D1S214 was 3.77 and 3.58. The MLS by multipoint analysis was 6.13 for D1S253. The MLS for D8S556 by single-point analysis was 4.20. The MLS for DXS1232 was 2.35 by single-point analysis, whereas the MLS for the region 2 cM right to DXS1232 and the region between DXS1227 and DXS1200 was 3.03 and 2.93 by multi-point analysis. Three principal chromosome regions of linkage, D1S253/214, D8S556 and DXS1232, have been identified which we call RA1, RA2 and RA3 for RA disease loci.

Arthritis, Rheumatoid↗
PubMed1998

Antibacterial action of vinegar against food-borne pathogenic bacteria including Escherichia coli O157:H7.

The bacteriostatic and bactericidal actions of vinegar on food-borne pathogenic bacteria including enterohemorrhagic E. coli (EHEC) O157:H7 were examined. The growth of all strains evaluated was inhibited with a 0.1% concentration of acetic acid in the vinegar. This inhibition was generally increased in the presence of sodium chloride or glucose. There was almost no difference in sensitivity to the bacteriostatic action of vinegar among the strains of pathogenic E. coli. Vinegar had a bactericidal effect on food-borne pathogenic bacteria including EHEC O157:H7. This action against EHEC O157:H7 was synergically enhanced by sodium chloride but was attenuated with glucose. For EHEC strains (O157:H7, O26:H11, O111:HNM) the difference in the inactivation rate due to vinegar among strains used was small, although an enteropathogenic E. coli (EPEC) O111:K58:H- strain was more sensitive, being more quickly killed compared with EHEC strains. The inactivation rate due to vinegar was constant irrespective of inoculum size. However, it differed greatly depending on growth phase of the cells, where logarithmic growth phase cells were more sensitive and easily killed than stationary phase cells. The bactericidal activity of vinegar increased with the temperature. Various conditions for bactericidal effects on EHEC O157:H7 were examined by the multiparametric analysis of five factors: acetic acid concentration in the vinegar, sodium chloride concentration, temperature, incubation time, and viable cell number. The combined use of vinegar and sodium chloride, with use of an appropriate treatment temperature, was found to be markedly effective for the prevention of bacterial food poisoning.

Acetic Acid↗
PubMed1998

[Apoptosis induced by excitatory sulfur amino acids in primary cultured rat immature cerebral neurons].

In the neural tissue of patients with amyotrophic lateral sclerosis (ALS), the elevation of taurine, the final product of the metabolic pathway of sulfur amino acids (SAAs), has been reported, suggesting that excitatory SAAs, the intermediates of this pathway, could also be increased. This study was undertaken to evaluate whether excitatory SAAs have the ability to inhibit cystine uptake. Since immature neurons have not yet expressed the receptor channels, they are not susceptible to excitotoxicity. Inhibition of cystine transport leads to a depletion of glutathione, and results in cell death due to oxidative stress. Cell cultures were obtained from the cerebral cortex of fetal Wistar rats. Cytotoxicity studies were performed 48 hours after plating by addition of the culture medium containing SAAs; cysteine sulfinic acid, cysteic acid, homocysteine sulfinic acid (HCSA), homocysteic acid (HCA) and S-sulfocysteine. Cell death was quantified by the release of the cytosolic enzyme lactate dehydrogenase, and single cell assessment of apoptosis was carried out by staining cells with acridine orange, DNA isolation and agarose gel electrophoresis were also performed. Protection of cycloheximide, a protein synthesis inhibitor, against non-receptor mediated excitatory SAA cytotoxicity was also assessed. HCA and HCSA showed cytotoxicity, the morphology and biochemistry of which were compatible to apoptosis. It will be a subject for future study to examine whether this mechanism of cell death is primarily present in ALS.

Amyotrophic Lateral Sclerosis↗
PubMed1998

Expression of the 150-kd oxygen-regulated protein in human breast cancer.

Tumor cells subjected to environmental stress, such as oxygen deprivation followed by reoxygenation, redirect biosynthetic pathways to express oxygen-regulated proteins (ORPs) and heat-shock proteins (HSPs). The 150-kd oxygen-regulated protein (ORP150) is a novel endoplasmic reticulum-associated polypeptide in the HSP70 family. In view of links between expression of HSPs/ORPs and tumor properties, especially tumor invasiveness and resistance to therapeutic regimens, expression of ORP150 in human breast cancers was examined. Western and Northern blotting demonstrated elevated expression of ORP150 in breast cancer, regardless of estrogen receptor status, compared with normal breast tissue. Immunohistochemical and in situ hybridization techniques revealed that infiltrating cancer cells in the stroma expressed ORP150 more strongly than large nests of cancer cells. Furthermore, pancreatic and thyroid carcinomas also displayed greater ORP150 expression. These results suggest that ORP150 is up-regulated in tumors and, in breast tumors, may be associated with tumor invasiveness.

Adenocarcinoma, Mucinous↗
PubMed1998

[Releasing phenomenon of learned movements].

Involuntary movements that resembled the shooting of a basketball and piano playing were observed after brain damage in a 13-year-old female and a 74-year-old female, respectively. The movements were characterized as involuntarily triggered movements that occurred in the presence and absence of exteroceptive stimuli, movements had been practiced repeatedly just before the occurrence of the brain damage, and that could be stopped on command. According to the MRI findings, the lesions extended into the pre-supplementary motor area (pre-SMA). The characteristics of the patients movements were different from previously reported involuntary movements such as compulsive manipulation of tools, utilization behavior, and imitation behavior. Hikosaka et al (1996) reported the role of the pre-SMA in learning new sequential procedures. We speculate that damage to the pre-SMA may be associated with the etiology of these movements.

Adolescent↗