Biomedical subjects

Y Taniguchi

Publications and source records attributed to Y Taniguchi.

At least 19 recordsLinked to original sources

PubMed1999

Globular Cluster Formation Triggered by the Initial Starburst in Galaxy Formation.

We propose and investigate a new formation mechanism for globular clusters in which they form within molecular clouds that are formed in the shocked regions created by galactic winds driven by successive supernova explosions shortly after the initial burst of massive star formation in the galactic centers. The globular clusters have a radial distribution that is more extended than that of the stars because the clusters form as pressure-confined condensations in a shell that is moving outward radially at high velocity. In addition, the model is consistent with existing observations of other global properties of globular clusters, as far as comparisons can be made.

Journal Article↗

PubMed1999

Assessment of cerebrospinal fluid levels of serum amyloid P component in patients with Alzheimer's disease.

Serum amyloid P component (SAP) is a normal plasma constituent that is observed both in senile plaque and in neurofibrillary tangle in brains of patients with Alzheimer's disease (AD). In this study, we evaluated the SAP levels in cerebrospinal fluid (CSF) of 72 patients with AD, 11 frontotemporal dementia and nine normal control subjects. There was no significant difference in the SAP levels between the AD group and other groups. However, among AD patients, cognitive function was rated using the Mini-Mental State Examination and was correlated with the SAP level (R = 0.38, P < 0.05). Our results suggest that measurement of the SAP levels in CSF can be useful for assessing the degree of cognitive impairment in AD patients.

Aged↗

PubMed1999

Fourier-transform infrared spectroscopy study of the pressure-induced changes in the structure of the bovine alpha-lactalbumin: the stabilizing role of the calcium ion.

The Fourier-transform infrared spectroscopy (FTIR) technique with a diamond anvil cell has been applied for examination of the pressure-induced changes occurring in the secondary structure of the alpha-lactalbumin. This is the first high-pressure FTIR study of a calcium-binding protein which simultaneously takes into account spectral changes in both the calcium-ion-binding carboxyl groups' band and the amide I/I' vibrational band. Spectral behavior of three kinds of the protein: the undeuterated holoform, the fully deuterated holoform, and the undeuterated apoform was compared in the pressure range from 0.1 MPa up to 740 MPa. We found that the binding of calcium remarkably stabilizes the alpha-lactalbumin against pressure as it is followed approximately by a 200-MPa increase of the value of pressure at which denaturation occurs. A quantitative analysis of the band of antisymmetrical stretching vibrations of the calcium-binding carboxyl groups revealed that the pressure-induced changes in the calcium-binding loop occur in two stages. Binding of the calcium ion seemingly increases the pressure-stability of the calcium-binding loop to a higher degree than the pressure-stability of the secondary structure of the alpha-lactalbumin. We have also discussed in detail the complex pressure-enhanced H/D exchange in the alpha-lactalbumin. Finally, we have proposed a new assignment of major peaks in the helical region of the amide I/I' spectral band of the partially deuterated alpha-lactalbumin.

Animals↗

PubMed1999

Impaired regeneration and no amelioration with aldose reductase inhibitor in crushed unmyelinated nerve fibers of diabetic rats.

The regenerative ability of unmyelinated nerve fibers (UNFs) in diabetes and the effect of aldose reductase inhibitor (ARI) on it were ultrastructurally evaluated after sciatic nerve crush in control and untreated and tolrestat-treated streptozocin-induced diabetic rats. The density and number of UNFs were significantly increased in all groups at 5 weeks after the injury. The increase returned to the baseline level in control rats, but not in diabetic rats at 24 weeks. Although the axon size showed a marked decrease at 5 weeks and an incomplete recovery at 24 weeks in all groups, the recovery was significantly worse in diabetic than in control groups. Tolrestat did not have any effect on regeneration of UNFs in diabetes. These results suggest impaired regeneration of UNFs after nerve crush injury in diabetes and less therapeutic effect of ARI on it.

Aldehyde Reductase↗

PubMed1999

The receptor protein tyrosine phosphatase, PTP-RO, is upregulated during megakaryocyte differentiation and Is associated with the c-Kit receptor.

We have recently isolated a cDNA encoding a novel human receptor-type tyrosine phosphatase, termed PTP-RO (for a protein tyrosine phosphatase receptor omicron), from 5-fluorouracil-treated murine bone marrow cells. PTP-RO is a human homologue of murine PTPlambda and is related to the homotypically adhering kappa and mu receptor-type tyrosine phosphatases. PTP-RO is expressed in human megakaryocytic cell lines, primary bone marrow megakaryocytes, and stem cells. PTP-RO mRNA and protein expression are upregulated upon phorbol 12-myristate 13-acetate (PMA) treatment of the megakaryocytic cell lines CMS, CMK, and Dami. To elucidate the function of PTP-RO in megakaryocytic cells and its potential involvement in the stem cell factor (SCF)/c-Kit receptor pathway, COS-7 and 293 cells were cotransfected with the cDNAs of both the c-Kit tyrosine kinase receptor and PTP-RO. PTP-RO was found to be associated with the c-Kit receptor in these transfected cells and the SCF/Kit ligand induced a rapid tyrosine phosphorylation of PTP-RO. Interestingly, these transfected cells demonstrated a decrease in their proliferative response to the SCF/Kit ligand. In addition, we assessed the association of PTP-RO with c-Kit in vivo. The results demonstrated that PTP-RO associates with c-Kit but not with the tyrosine kinase receptor FGF-R and that PTP-RO is tyrosine-phosphorylated after SCF stimulation of Mo7e and CMK cells. Antisense oligonucleotides directed against PTP-RO mRNA sequences significantly inhibited megakaryocyte progenitor proliferation. Therefore, these data show that the novel tyrosine kinase phosphatase PTP-RO is involved in megakaryocytopoiesis and that its function is mediated by the SCF/c-Kit pathway.

Adolescent↗

PubMed1999

Development of a sensitive enzyme-linked immunosorbent assay for eotaxin and measurement of its levels in human blood.

The CC chemokine eotaxin is potent eosinophil-selective chemoattractant, and it is thought that the function of eotaxin is closely related to the recruitment of eosinophils in certain inflammatory reactions. In order to learn more about the biological role of this molecule, we have developed a new sandwich ELISA method to measure human eotaxin using two monoclonal anitibodies and purified recombinant eotaxin as a standard. The minimal detectable concentration of eotaxin in this assay was 1.5 pg/ml, and the working range was 3.1--200 pg/ml with low CVs (< 10%). Both within- and between-run precision levels were less than 6.7% of the CVs. The dilution curves of two serum and two spiked plasma samples showed good linearity and the recovery range was 92.8--103.3%. No cross-reactivity was found with other similar chemokines. MCP-1, MCP-2, MCP-3, MCP-4, eotaxin-2 and RANTES. This assay was sensitive enough to measure the circulating eotaxin levels of healthy volunteers. However, the eotaxin levels in serum samples (mean+/-SD; 68.6+/-13.4 pg/ml, n=15) were significantly higher than those in matched plasma samples (19.2+/-5.4 pg/ml) separated from blood collected in tubes containing EDTA. Kinetic studies revealed that the eotaxin levels in serum markedly increased depending on the elapsed time before separation from blood cells, but such changes in EDTA-plasma were negligible up to 4 h at 25 degrees C. Our new ELISA is an accurate and useful method for quantifying human eotaxin in blood and demonstrates that the process of preparing blood samples affects the measurement of the eotaxin levels.

Chemokine CCL11↗

PubMed1999

Primary structure of a visual pigment in bullfrog green rods.

In frog retina there are special rod photoreceptor cells ('green rods') with physiological properties similar to those of typical vertebrate rods ('red rods'). A cDNA fragment encoding the putative green rod visual pigment was isolated from a retinal cDNA library of the bullfrog, Rana catesbeiana. Its deduced amino acid sequence has more than 65% identity with those of blue-sensitive cone pigments such as chicken blue and goldfish blue. Antisera raised against its C-terminal amino acid sequence recognized green rods. It is concluded that bullfrog green rods contain a visual pigment which is closely related to the blue-sensitive cone pigments of other non-mammalian vertebrates.

Amino Acid Sequence↗

PubMed1999

Physical interactions among circadian clock proteins KaiA, KaiB and KaiC in cyanobacteria.

The kai gene cluster, which is composed of three genes, kaiA, kaiB and kaiC, is essential for the generation of circadian rhythms in the unicellular cyanobacterium Synechococcus sp. strain PCC 7942. Here we demonstrate the direct association of KaiA, KaiB and KaiC in yeast cells using the two-hybrid system, in vitro and in cyanobacterial cells. KaiC enhanced KaiA-KaiB interaction in vitro and in yeast cells, suggesting that the three Kai proteins were able to form a heteromultimeric complex. We also found that a long period mutation kaiA1 dramatically enhanced KaiA-KaiB interaction in vitro. Thus, direct protein-protein association among the Kai proteins may be a critical process in the generation of circadian rhythms in cyanobacteria.

Amino Acid Sequence↗

PubMed1999

Evolution of visual pigments in geckos.

Most geckos are nocturnal forms and possess rod retinas, but some diurnal genera have pure-cone retinas. We isolated cDNAs encoding the diurnal gecko opsins, dg1 and dg2, similar to nocturnal gecko P521 and P467, respectively. Despite the large morphological differences between the diurnal and nocturnal gecko photoreceptor types, they express phylogenetically closely related opsins. These results provide molecular evidence for the reverse transmutation, that is, rods of an ancestral nocturnal gecko have backed into cones of diurnal geckos. The amino acid substitution rates of dgl and dg2 are higher than those of P521 and P467, respectively. Changes of behavior regarding photic environment may have contributed to acceleration of amino acid substitutions in the diurnal gecko opsins.

Amino Acid Sequence↗

PubMed1999

Establishment and characterization of a second primary osteosarcoma cell line (OSrb/N-M) from a patient cured of bilateral retinoblastoma.

A cell line, designated OSrb/N-M, was established from the second primary osteosarcoma that developed in a 17-year-old Japanese female patient who had suffered from bilateral retinoblastoma at infancy. The OSrb/N-M cells grew as an adherent monolayer and retained some osteogenic biochemical phenotypes. In cytogenetic analyses, this cell line revealed many structural and numerical abnormalities, however, the bands q14 of both chromosomes 13 appeared to be normal, whereas the constitutional cells displayed normal female karyotypes. Immunoblot studies using monoclonal antibodies specific to RB protein demonstrated that the tumor cells did not express RB protein, suggesting that the OSrb/N-M cells might suffer from a loss-of-function mutation at this gene locus. Thus, this cell line is useful to study the molecular mechanism for the tumorigenesis of osteosarcoma with regard to an association with retinoblastoma.

Adolescent↗

PubMed1999

Chromosomal mapping of two RBP-J-related genes: Kyo-T and RBP-L.

We have recently isolated two genes encoding proteins which have either homology or affinity to RBP-J, a transcription factor involved in Notch signaling. Kyo-T interacts with RBP-J and possibly regulates the function of RBP-J. RBP-L has a highly homologous region with RBP-J but the function of RBP-L is unknown. Fluorescence in situ hybridization analysis of human metaphase chromosomes localized Kyo-T and RBP-L to Xq26 and 20q12-13.1, respectively.

Base Sequence↗

PubMed1999

Sintered bone implantation for the treatment of benign bone tumours in the hand.

We report the results of treatment of benign bone tumours in the hand with curettage and sintered bone implantation using bovine sintered bone (True Bone Ceramics). There were 22 patients who underwent sintered bone implantation in our department in 1984 or later. The follow-up survey period varied from 9 months to 11 years and 2 months (mean, 5.8 years). Recurrence of tumours and complications such as infection or fracture were not observed, and there were no clinical symptoms. X-rays revealed new bone formation connecting the implanted blocks to bone. Sintered bone was not absorbed, and lucent zones around the implants or other abnormal findings were not observed. Bone union was achieved in all patients who had pathological fractures before surgery.

Adolescent↗

PubMed1999

Variation of P-QRS relation during atrioventricular node reentry tachycardia.

OBJECTIVES: The main objective of this study was to characterize the phenomenon of variation in the P-QRS relation during atrioventricular node reentry tachycardia. BACKGROUND: Variation of P-QRS relation during tachycardia has been observed occasionally in atrioventricular node reentry tachycardia. However, the incidence, the characteristics and the mechanisms of this phenomenon have not been investigated previously. METHODS: Retrospective analysis was performed in 311 consecutive patients with slow-fast form and 108 patients with atypical or multiple form of atrioventricular node reentry tachycardia to examine whether variation of P-QRS relation with changes in AH, HA and AH/HA (A = atria; H = His bundle) ratio occurred during tachycardia. RESULTS: A total of 28 patients, 8 with slow-fast and 20 with atypical or multiple tachycardias, were found to manifest this phenomenon. There were 6 males and 22 females, with an average age of 38+/-16 years. In 10 patients, this phenomenon occurred transiently following electrical induction of the tachycardia. In 15 patients, changes in AH, HA and AH/HA ratio were associated with the occurrence of Wenckebach or 2:1 block proximal to the His bundle (H) recording site without interruption of the tachycardia. In nine patients, three with nonsustained tachycardia and six after administration of adenosine triphosphate, this phenomenon was observed at the termination of the tachycardia. This phenomenon was usually accompanied by a mild lengthening of the tachycardia cycle length. CONCLUSIONS: Variation of P-QRS relation with or without block may occur during atrioventricular node reentry tachycardia, especially in atypical or multiple-form tachycardias. It was postulated that decremental conduction in the distal common pathway, which exists between the distal link of the reentry circuit and the H, is primarily responsible for this phenomenon.

Adenosine Triphosphate↗

PubMed1999

IgE reactivity and cross-reactivity of Japanese monkeys (Macaca fuscata) to Japanese cedar (Cryptomeria japonica) and cypress (Chamaecyparis obtusa) pollen allergens.

BACKGROUND: The natural occurrence of Japanese cedar (Cryptomeria japonica, CJ) pollinosis has been reported in Japanese monkeys (Macaca fuscata). However, the reactivity to Japanese cypress (Chamaecyparis obtusa, CO) pollen allergens in these monkeys has not yet been reported. OBJECTIVES: The present study was designed to investigate the reactivity to CO pollen allergens in monkeys sensitized to CJ pollen allergens. METHODS: Serum samples from 40 monkeys naturally sensitized to CJ pollen allergens were collected from four troops. We measured the specific IgE to CO pollen allergens and examined the reactivity to the allergens by intradermal test. Cross-reactivity between CJ and CO pollen allergens was examined by ELISA inhibition method. Furthermore, we examined the sensitivity to the allergens by histamine release assay from leucocytes. RESULTS: All 40 monkeys had specific IgE to crude and purified major allergens (Cha o 1) of CO pollen. The monkeys showed a positive reaction to CO pollen allergens in the intradermal test. Allergenic cross-reactivity between Cha o 1 and Cry j 1 (a major allergen in CJ pollen) was also observed. Specific histamine release to both the major allergens was noted in two monkeys with CJ pollinosis. CONCLUSION: Japanese monkeys sensitized to Japanese cedar pollen allergens also demonstrate reactivity to Japanese cypress pollen allergens.

Allergens↗

PubMed1999

Major organ function under mechanical support: comparative studies of pulsatile and nonpulsatile circulation.

We examined a major organ function during 3 h biventricular assisted circulation after acute myocardial infarction model in the pig. In left ventricular circulation, the outflow cannula was placed in the ascending aorta and an inflow cannula through the mitral valve in the left ventricle. A pump (pulsatile group, Zeon Medical, Inc., Tokyo, Japan and nonpulsatile group, Nikkiso HPM-15, Nikkiso, Inc., Tokyo, Japan) was connected to each cannula. In right ventricular circulation, the outflow cannula was placed in the pulmonary artery and an inflow cannula in the right ventricle. The right ventricular circulation was supported by a nonpulsatile pump (Nikkiso HPM-15). The items measured were the regional blood flows of the cortex and medulla in the kidney, white matter and gray mater in brain, and liver; renal arterial flow; carotid arterial flow; portal vein flow; common hepatic arterial flow; arterial ketone body ratio (AKBR); and lactate/pyrubic acid (L/P). In the pulsatile group, the renal cortical blood flow increased, and the medulla blood flow decreased. On the other hand, in the nonpulsatile group, both regional blood flows decreased. That means that in the pulsatile assisted group intrarenal redistribution improved rather than in the nonpulsatile assisted group. In addition the liver regional blood flow, AKBR, and L/P showed significant differences between the pulsatile and nonpulsatile groups. On the other hand, the white matter and gray matter regional blood flows and carotid arterial flow did not show significant differences between the groups. The results of our study indicated that pulsatile circulation produced superior circulation in the kidney and liver, and microcirculation on the cell level was superior as well in early treatment of acute heart failure.

Animals↗

PubMed1999

Posterior interosseous nerve syndrome due to pseudogout.

Posterior interosseous nerve palsy associated with pseudogout of the elbow joint in a 71-year-old woman is described. Local steroid injection and administration of a nonsteroidal anti-inflammatory drug was effective in treatment.

Adrenal Cortex Hormones↗

PubMed1999

Localization of transforming growth factors beta1 and beta2 and epidermal growth factor in IgA nephropathy.

OBJECTIVE: The localization of transforming growth factor (TGF)-beta1. TGF-beta2 and epidermal growth factor (EGF) was investigated in IgA nephropathy, and was compared with the severity of histological damage (including tubulointerstitial lesions). MATERIALS AND METHODS: The enzyme antibody method was used to stain paraffin-embedded sections of renal tissue from 42 patients with IgA nephropathy (19 males and 23 females). RESULTS: There was a significant correlation between glomerular positivity for TGF-beta1 and TGF-beta2 and the severity of histological damage. There was also a significant correlation between positivity for TGF-beta1 and TGF-beta2 in the tubular epithelium and tubulointerstitial lesions. In contrast, there was no relationship between glomerular positivity for EGF and histological damage, although there was a significant correlation between positivity for EGF in the tubular epithelium and tubulointerstitial lesions. CONCLUSIONS: These findings suggest that TGF-beta1 and TGF-beta2 may be important in the progression of IgA nephropathy, and that the distribution of EGF may also be a useful marker for the progression of renal damage, including tubulointerstitial lesions.

Adolescent↗

PubMed1999

Effects of OK-432 on the proliferation and cytotoxicity of lymphokine-activated killer (LAK) cells.

We studied the effect of a streptococcal preparation, OK-432, on the cytotoxicity and the proliferation of lymphokine-activated killer (LAK) cells for use in adoptive immunotherapy. Peripheral blood mononuclear cells (PBMC) were derived from healthy donors and patients with malignant brain tumors. We divided PBMC into two groups; these cells then were stimulated with interleukin-2 in the presence or absence of OK-432. OK-432 was added only in the initial 3 days during the 3-week midterm culture period. Then, we compared OK-432-stimulated LAK (OK-LAK) cells with standard LAK (sLAK) cells in terms of their rate of proliferation and cytotoxicity. OK-LAK cells proliferated more rapidly than sLAK cells. The cytotoxicity of OK-LAK cells increased, whereas that of sLAK cells decreased. We also investigated the phenotypic differences between these two types of LAK cells and found that, on day 21, the OK-LAK cells consisted mostly of CD3-CD56+ NK cells, whereas the sLAK cells consisted mostly of CD3+CD56- T cells. The difference in their level of cytotoxic potential might be explained by the difference of predominant phenotype.

Antigens, CD↗