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T Yasuda

Publications and source records attributed to T Yasuda.

At least 379 records · Page 21Linked to original sources
PubMed1995

Activity staining of mammalian ribonuclease inhibitors after electrophoresis in sealed vertical slab polyacrylamide gels.

A method for detecting the activity of ribonuclease inhibitors (RIs) after nondenaturing polyacrylamide gel electrophoresis and isoelectric focusing was developed. Both types of electrophoresis were performed using vertical slab polyacrylamide gels in the presence of dithiothreitol and in a sealed system. In each system, purified 50 kDa human RI was visualized as a single band by immunoblotting with a specific antibody. RI activity in the polyacrylamide gel slab was detected by sandwiching the gel slab between a cellulose acetate membrane moistened with a solution of bovine pancreatic ribonuclease A and a dried agarose film sheet containing substrate yeast RNA plus ethidium bromide and incubating at 37 degrees C. The ribonuclease penetrated the polyacrylamide gel and digested the substrate RNA in the agarose film. However, if an RI was present in the gel, the enzyme was inactivated by complex formation. Fluorescent bands corresponding to RIs were observed on a dark background under ultraviolet light. This activity staining had a high sensitivity allowing detection of less than 0.6 units of mammalian RIs (corresponding to 5 ng of purified human RI) and produced a sharp band which compared favorably with that obtained on immunoblotting. These electrophoretic techniques appear useful for the investigation of RIs in heterogeneous biological samples.

Animals↗
PubMed1995

Apoptosis occurs in the oligodendroglial lineage, and is prevented by basic fibroblast growth factor.

During the perinatal period, oligodendroglial precursor cells proliferate rapidly, then cease dividing and differentiate into oligodendroglia. Many of these newly formed oligodendroglia are destined to die. We now demonstrate that oligodendroglia generated in passaged cultures of rat forebrain oligodendroglial precursor cells after removal of basic fibroblast growth factor (basic FGF) from the medium often undergo internucleosomal DNA nicking and nuclear fragmentation, features characteristic of apoptosis. These alterations are rare in cultures maintained continuously in basic FGF. As in many other cellular lineages susceptible to apoptosis, these degenerative changes can be prevented by treatment with the endonuclease antagonist, aurintricarboxylic acid, or by inhibiting de novo RNA or protein synthesis. Supplementation of the basic FGF-free medium with insulin, insulin-like growth factor-1, platelet-derived growth factor, or ciliary neuronotrophic growth factor also diminishes DNA nicking. Both oligodendroglial differentiation and DNA nicking are induced in basic FGF-treated cultures by inhibiting DNA synthesis with aphidicholin or excess thymidine, thus suggesting a close linkage between the anti-apoptotic, anti-differentiation, and mitogenic effects of basic FGF on the oligodendroglial lineage.

Animals↗
PubMed1995

The molecular basis for genetic polymorphism of human deoxyribonuclease I: identification of the nucleotide substitution that generates the fourth allele.

In addition to the three alleles commonly responsible for the protein polymorphism of human deoxyribonuclease I, a mutation encoded by a fourth allele, DNASE1*4, was detected by isoelectric focusing. All 8 exons covering the entire open reading frame of the human DNase I gene were amplified by the polymerase chain reaction and subjected to direct sequencing. Only one nucleotide substitution, a C-to-G transition (CAG-->GAG), in the codon for amino acid 9 of the mature enzyme was found. This substitution resulted in the replacement of Gln with Glu (Q9E).

Alleles↗
PubMed1995

Light-dependent inhibition of protein kinase C and superoxide generation of neutrophils by hypericin, an antiretroviral agent.

Hypericin, a photosensitizing plant pigment, has antiretroviral activity. When exposed to light, the inhibition of Friend leukemia virus (FLV)-induced splenomegaly by hypericin was increased. The ID50 was decreased to less than 2.5 micrograms/mouse by exposure to tungsten light (29 x 10(-3) W/cm2 for 3 min). This pigment inhibited phorbol 12-myristate 13-acetate (PMA)-activated protein kinase C of rat brain in a light- and concentration-dependent manner. The ID50 of hypericin and the light intensity for inhibition of PKC were 0.1 microM under a constant light of 29 x 10(-3) W/cm2 for 3 min and 5 x 10(-3) W/cm2 in the presence of 1 microM hypericin for 3 min, respectively. The PMA-induced respiratory burst of neutrophils was inhibited in the light but stimulated in the dark by hypericin. The ID50 for inhibition of the respiratory burst was similar to that for inhibition of PKC. These results suggest that hypericin might inhibited PKC-mediated processes of intact cells, including PMA-induced superoxide generation of neutrophils by some light-dependent mechanism, and that this mechanism might underlie its light-dependent inhibition of FLV infection.

Animals↗
PubMed1995

Genotyping of human deoxyribonuclease I polymorphism by the polymerase chain reaction.

We recently completely elucidated the molecular basis of genetic polymorphism in human deoxyribonuclease I and found it to be controlled by four codominant alleles, DNASE1*1, *2, *3 and *4. In this paper we describe a novel DNase I-genotyping system that could be used directly on DNA samples using the polymerase chain reaction (PCR) based on the three nucleotide substitutions underlying the protein polymorphism. The system consists of three independent reactions. Since the substitutions neither suppress nor create any known enzyme recognition site in the DNase I gene, two separate mismatched PCR followed by XhoI digestion methods were introduced to discriminate between the DNASE1*1 (or *3) and the DNASE1*2 (or *4) alleles, and to detect the DNASE1*4 allele. An amplification refractory mutation system was employed to detect DNASE1*3. A 100% correlation was found between the results of this genotyping method and those obtained by phenotyping using conventional isoelectric focusing. The high sensitivity and specificity of this genotyping method allows us to survey DNase I-polymorphism in small DNA samples.

Alleles↗
PubMed1995

X-linked recessive bulbospinal neuronopathy: clinical phenotypes and CAG repeat size in androgen receptor gene.

Clinical phenotypes and the CAG repeat size of the androgen receptor gene were assessed in 95 Japanese patients with X-linked recessive bulbospinal neuronopathy. There was an age- and duration-dependent deterioration of muscle strength, ADL scores, and plasma creatine kinase levels. However, there was no correlation between the presence of absence of gynecomastia or diabetes mellitus and the age at onset or duration of illness. Correlations were present between the CAG repeat size and the age at onset (P < 0.0001) as well as the presence or absence of gynecomastea (P < 0.05). Muscular weakness and ADL scores were also correlated with the CAG repeat size only when they were adjusted by the age at examination not by the duration of illness. These findings suggest that CAG repeat size is one of the determinant factors of disease progression. However, extensive variation in phenotypic severity in patients with the same size of CAG repeat was present even among the siblings, suggesting that other factors than CAG repeat size influence the phenotypic manifestation. The average gain of CAG repeat size expansion was a 1.4 repeat in paternal transmission which was more unstable than that in maternal transmission, but the magnitude of the expansion in paternal transmission was much smaller than is presently known for other diseases in which CAG repeat expansion is the responsible gene defect.

Adolescent↗
PubMed1995

m-calpain in rat growth plate chondrocyte cultures: its involvement in the matrix mineralization process.

m-Calpain, a Ca(2+)-dependent neutral cysteine proteinase (EC 3.4.22.17), has been demonstrated to be present in the lower hypertrophic zone of the rat growth plate. Using the pelleted culture system as an in vitro model of rat epiphyseal chondrocyte differentiation, we studied m-calpain contents and activities in pelleted cultures during chondrocyte differentiation and the role of m-calpain in the mineralization process. m-Calpain was demonstrated immunohistochemically in epiphyseal chondrocytes, and immunoreactive m-calpain content in cells increased with terminal differentiation into hypertrophic cells. Immunoblotting also showed the association of the increase in m-calpain in cell pellets and in cell culture medium with development of the culture. Ca(2+)-dependent caseinolytic activities of m-calpain extracted from cell pellets and from the medium increased with chondrocyte differentiation, coincident with the increase in enzyme content. The inhibition of m-calpain by the addition of calpastatin, a specific inhibitor of calpain, caused suppression of matrix mineralization in pelleted cultures; the addition of E-64c, a specific inhibitor of cysteine proteinases, during the mineralization stage also caused a significant inhibition of the matrix mineralization. The addition of E-64c resulted in altered composition of proteoglycan monomers and aggregates in cell pellets and in suppression of mineral growth. These findings support an important role of cysteine proteinases, especially m-calpain, in the regulation of the cartilage mineralization process through proteoglycan degradation.

Alkaline Phosphatase↗
PubMed1995

Tetrahymena intramitochondrial filamentous inclusions contain 14-nm filament protein/citrate synthase.

Tetrahymena 14-nm filament protein has been shown to have dual functions as a citrate synthase in mitochondria and as a cytoskeletal protein in oral morphogenesis and pronuclear behavior during conjugation. Immunofluorescence studies of the 14-nm filament protein/citrate synthase in mitochondria found that intense mitochondrial fluorescence remained unchanged in Tetrahymena cells taken from logarithmic growth phase to stationary phase. However, electron microscopic studies showed that electron-dense rod-shaped structures found in mitochondrial matrices tended to increase in Tetrahymena cells in the growth decline phase. The rods were composed of side-by-side straight filaments with diameters of approximately 14 to 16 nm. Serial sections revealed that in Tetrahymena cells in growth decline phase, one to four electron-dense rods existed in the matrices of every mitochondrion. Immunoelectron microscopy using an anti-14-nm filament antibody clearly showed that a filament bundle of the electron-dense rod was the bundle of polymerized filaments of 14-nm filament protein/citrate synthase. These results strongly suggest that dynamic monomer-polymer conversion of the 14-nm filament protein/citrate synthase in mitochondria depends upon the physiological conditions of Tetrahymena cells.

Animals↗
PubMed1995

Leishmania donovani: pilot study for evaluation of therapeutic effects of inosine analogs against amastigotes in vitro and in vivo.

The inhibition of carbocyclic inosine (C-Ino), 3'-deoxyinosine (3'-dI), and 3'-fluoroinosine (3'-FI) to Leishmania donovani amastigotes was examined. J774.1 cells (a mouse macrophage line) were cultured in GIT medium with lipopolysaccharide and hemin and infected with the parasite. C-Ino (3 microM) completely inhibited and 3'-dI (30 microM) reduced to 40% the infection rate on Day 6 after infection. Pentostam (30 microM) resulted in a 38% infection rate. The therapeutic efficacies of nonentrapped free and liposome-entrapped inosine analogs were tested in mice infected with L. donovani. The mice were injected intravenously five times on alternate days, beginning 2 days after infection. Treatment with the nonentrapped free inosine analog of C-Ino (100 mg/kg), 3'-dI (100 mg/kg), or 3'-FI (50 mg/kg) resulted in an LDU that was 94, 68, or 73% lower, respectively, than the control values. Treatment with the corresponding entrapped inosine analog (10 mg/kg) caused decreases of 90, 69, or 68% LDU, respectively. The entrapped inosine analogs were inhibitory at doses one-fifth to one-tenth of the nonentrapped free inosine analogs. C-Ino had the strongest inhibitory effect among the three analogs tested in vitro and in vivo. Liposome-entrapped C-Ino had no severe side effects, although spleen weight increased. The agent may be useful as an anti-leishmanial drug.

Animals↗
PubMed1995

Clinico-pathophysiological features of acute autonomic and sensory neuropathy: a long-term follow-up study.

We evaluated the clinico-pathophysiological features of three patients with acute autonomic and sensory neuropathy (AASN) who were followed for over 3 years. Signs of an autonomic disturbance including vomiting, anhidrosis, urinary disturbances, orthostatic hypotension and reduced coefficient of variation of the R-R interval on electrocardiography gradually improved about 1 year after onset. However, all three exhibited severe generalized sensory impairment for all modalities with the development of persistent sensory ataxia. No sensory nerve action potentials could be elicited and no somatosensory evoked potentials could be obtained. Sural nerve biopsy revealed severe axonopathy. In two patients, a high-intensity area was observed in the posterior column of the spinal cord on T2*-weighted axial magnetic resonance images. The level of neuron-specific enolase in cerebrospinal fluid was markedly elevated in two patients, indicating spinal nerve root or sensory neuron damage. Motor nerve function was well preserved in all patients. Our findings suggests that the major lesion in patients with AASN, particularly those with a sensory deficit, is present in the dorsal root ganglion neurons, that is there is a ganglioneuronopathy.

Action Potentials↗
PubMed1995

Acanthamoeba sp. from the Philippines: electron microscopy studies on naturally occurring bacterial symbionts.

The isolation of two plasmid-like circular DNAs, measuring 52 and 42 kbp, from an Acanthamoeba sp. from the Philippines has led to the demonstration of a bacterial endosymbiont occurring in this free-living amoeba. The 52-kbp band hybridized with a short sequence of cytochrome b gene and was identified as the mitochondrial DNA, whereas the 42-kbp band was identified as plasmid DNA of the bacterial symbionts on the basis of electron microscopy. The endosymbionts are gram-negative, rod-shaped bacteria measuring approximately 1.3 x 0.43 microns and numbering about eight to ten cells per section. They are randomly distributed in both cysts and trophozoites and are surrounded neither by a phagolysosomal membrane nor by a clear or electron-translucent region. The endosymbiont membrane appears to have a close association with ribosomes, which are seen to be more concentrated within the vicinity of the symbionts than elsewhere within the cytoplasm. Attempts to grow the symbionts and the amoebae separately have failed.

Acanthamoeba↗
PubMed1995

Magnetic resonance imaging of the corticospinal tracts in amyotrophic lateral sclerosis.

In 13 patients with amyotrophic lateral sclerosis (ALS), corticospinal tract lesions on spinal cord, brain and brain stem were examined by MR imaging. In 9 patients, areas of high signal intensity located in the dorsolateral columns coinciding with the lateral corticospinal tracts, were detected on axial T2*-weighted MR imaging of the cervical spinal cord using a gradient echo technique. In two patients, these spinal cord MR abnormalities corresponded well to the postmortem pathological findings of lateral corticospinal tract degeneration. T2-weighted abnormal MR signals along the corticospinal tract at the brain and brain stem were detected in 4 patients, all of whom also showed abnormal signals on cervical cord MR imaging. Four of 13 patients did not show any abnormal signals on brain and brain stem or spinal cord MR imaging. Spinal cord MR imaging provides a useful information regarding upper motor neuron lesions in ALS.

Adult↗
PubMed1995

Production of human monoclonal antibodies to i blood group by EBV-induced transformation: possible presence of a new glycolipid in cord red cell membranes and human hematopoietic cell lines.

To study the differentiation-associated glycolipid two anti-i mAb producers, GL-1 and GL-2, were established from the combination of EBV-induced transformation of normal PBL and immune lysis of fluorescent dye-trapped liposome-containing bovine i-active glycolipid. The mAb GL-1 reacted with both sialosylparagloboside and pentahexosyl ceramide and the bovine i-active glycolipid whereas mAb GL-2 reacted only with the bovine i-active glycolipid in LILA. Both mAbs cold-agglutinate human cord red cells but not adult red cells. However, unexpectedly, the majority of the reactivity of these mAbs in human cord red cells on TLC was not identical to the i-active glycolipid. The GL-1 antigenic substance is considered to be a glycolipid distinct from the i-active glycolipid because the immunoreactivity was canceled with endoglycoceramidase which cleaves a linkage between the oligosaccharide and ceramide. Based on complement cytolysis with the mAb, 15 hematopoietic cell lines and normal peripheral lymphocytes were screened for susceptibility to the mAbs. A Burkitt lymphoma cell line, Ramos, was most sensitive among those tested, and BJA-B, Daudi, Namalwa in the B cell lines, TALL-1, Jurkatt in the T-cell lines and HL-60 in the non-lymphoid cell lines were sensitive whereas normal lymphocytes or other 8 cell lines were not. An immunoreactive spot with the same Rf with cord red cells was also detected in sensitive cell lines. The possible presence of a new glycolipid antigen determined from the mAb and related to the differentiation of hematopoietic cells was speculated.

Antibodies, Monoclonal↗
PubMed1995

A combination of livedo racemosa, occlusion of cerebral blood vessels, and nephropathy: kidney involvement in Sneddon's syndrome.

A 59-year-old woman with retinal vein thrombosis and livedo racemosa had hematuria (4+) and proteinuria (1.7 g/day). Skin biopsy showed swollen blood vessel walls with infiltration of mononuclear cells, which were compatible with livedo racemosa (vasculitis). Magnetic resonance imaging (MRI) of the brain demonstrated multiple lacunar infarctions in the basal ganglia and white matter. Renal biopsy showed that small round cells had infiltrated into the interstitium, and a reticular structure was observed in the glomerular hilus. An amorphous substance composed of a single cell was present in the glomerular capillary lumen. Immunofluorescent study demonstrated the deposition of only IgA, in a segmental pattern differing from the diffuse global mesangial pattern seen in IgA nephropathy. After combined therapy including 40 mg/day prednisolone, 50 mg/day cyclophosphamide, antiplatelet drug, and anticoagulant was started, proteinuria and hematuria improved to 0.5 g/day and 2+, respectively, at the time of discharge. Sneddon's syndrome is a rare entity characterized by livedo racemosa and cerebrovascular lesions. In our patient with livedo racemosa, occlusion of cerebral blood vessels, and nephropathy with segmental immunoglobulin A (IgA) deposition, no antiphospholipid antibodies were detected on routine examination. Dermatologists, neurologists, psychiatrists, and nephrologists should be aware of the existence of Sneddon's syndrome with nephropathy (LI-O-N).

Antibodies, Antiphospholipid↗
PubMed1995

Voltage-dependent Ca2+ channels in the spiral ganglion cells of guinea pig cochlea.

Voltage-dependent Ca2+ channels in spiral ganglion cells (SGCs) isolated from guinea pig cochlea were investigated using the patch-clamp technique in a whole-cell recording mode. The voltage-dependent Na+ and K+ currents were blocked by adding tetrodotoxin, 4-aminopyridine, and tetraethylammonium to the external solution and by using choline or Cs+ in the external and internal solutions instead of Na+ or K+, respectively. The depolarizing voltage steps evoked inward currents with slow current decay. The maximum amplitude of the inward current increased in a hyperbolic manner with increasing extracellular Ca2+ concentration, indicating that the inward current was a voltage-dependent Ca2+ current (ICa). In 5 mM Ca2+ external solution, the ICa activated from a membrane potential around -60 mV and reached full activation at about -10 mV. The ICa inactivated from about -60 mV and became fully inactivated at about O mV, consistent with the high-voltage-activated Ca2+ channel subtype. Ionic selectivities for Ca2+ channels in SGCs were as follows: Ca2+ > Ba2+ > Sr2+. Effects of both inorganic and organic Ca2+ antagonists also were examined. The inhibitory strength was as follows: La3+ > Cd2+ > Ni2+ > or = Co2+ for inorganic Ca2+ antagonists, and flunarizine > nicardipine > methoxyverapamil > diltiazem for organic ones.

4-Aminopyridine↗