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Biomedical subjects

T Yasuda

Publications and source records attributed to T Yasuda.

At least 325 records · Page 18Linked to original sources
PubMed1997

Simple purification method of the antiphospholipid antibody from normal human plasma.

We have reported that rabbit serum contains a phospholipid (PL)/ganglioside-binding protein which adsorbs to Sephacryl S-400 gel and agglutinates human red blood cells. A new protein similar to the PL/ganglioside-binding protein was simply purified from normal human plasma using Sephacryl S-400, Sepharose CL-4B and DEAE-Sepharose CL-6B columns. The purified protein was found to agglutinate rabbit red blood cells. The hemagglutination was specifically inhibited by two PL, phosphatidylserine and phosphatidylinositol, but not by any other PL, gangliosides, saccharides or glycoproteins tested. From analyses of the N-terminal amino acid sequence and immunological specificity, the protein was identified to be a human immunoglobulin M.

Amino Acid Sequence↗
PubMed1997

Genetic polymorphisms detectable in human urine: their application to forensic individualization.

This review describes several types of genetic polymorphism, which have recently been identified in human urine in our laboratory, and have also been found in other human body fluids such as blood, saliva and semen. These include uropepsinogen, ribonuclease, deoxyribonuclease I (DNase I), deoxyribonuclease II (DNase II), 43-kDa glycoprotein, alpha-L-fucosidase, glutamate pyruvate transaminase, alpha-2-HS-glycoprotein, transferrin and vitamin D-binding protein. Several substances can be detected more easily in urine than in plasma. The concentrations of uropepsinogen, DNase I and DNase II in blood plasma are too low for analysis, whereas those in urine are high enough for easy typing. In practice, DNase I-polymorphism is one of the most useful genetic markers for practical purposes, because of its higher content in various body fluids including urine, a well-balanced gene frequency, and its easy and accurate detectability. Furthermore, several genetic markers previously identified in blood and/or other forensic samples can be phenotyped reproducibly and easily from the corresponding urine samples. Thus, urine, in addition to the convenience and non-invasive nature of its collection, is by no means inferior to blood as a sample source for typing in the field of forensic science. Biochemical and serological typing of genetic polymorphisms present in human urine could offer useful information to practising forensic biologists for forensic individualization of urine samples.

Deoxyribonuclease I↗
PubMed1996

Immunohistochemical study of advanced glycation end products in aging and Alzheimer's disease brain.

Advanced glycation end products (AGEs) in the brain were immunohistochemically examined in Alzheimer's disease (AD) and aging using anti-AGE antibody recognizing mainly carboxymethyllysine. AGE positive staining diffusely located in the neuronal perikarya of hippocampus and parahippocampus in AD and aged brains without dementia, but not in young brains less than 17 years of age. Extra-neuroperikaryal AGE deposits were also detected in the neuropil of AD and aged brains. The extra-neuroperikaryal AGE deposits markedly increased in AD brains as compared to aged brains. These AGE-positive deposits in the neuropil were not related to the senile plaque identified by anti-beta amyloid protein antibody. These findings suggest a potential link of AGE accumulation in the central nervous system to the aging process of neurons and the degenerating process of AD neurons.

Adolescent↗
PubMed1996

Regulation of extracellular matrix by mechanical stress in rat glomerular mesangial cells.

Increases in intraglomerular pressure are known to predispose to the development of glomerular sclerosis, which is characterized by accumulation of extracellular matrix within the glomerulus. Glomerular mesangial cells are exposed to pulsatile capillary pressures and are a potential target for mechanical stress. In the present studies, we subjected cultured rat mesangial cells to continuous cycles of stretching and relaxation (stretch/relaxation) and examined alterations in extracellular matrix gene expression. After 48 h of stretch/relaxation, immunofluorescent localization of matrix accumulation indicated increases in types I, III, and IV collagens, fibronectin, and laminin, with the greatest increases seen at the periphery of the culture dish, at the point of the greatest deformation. Northern blot analysis of total RNA revealed time-dependent induction of alpha1(I) collagen, alpha1(III) collagen, alpha1(IV) collagen, fibronectin, and laminin by stretch/relaxation, with maximal increases occurring between 12 and 24 h. Transient transfection of reporter gene constructs of the 5' flanking region of alpha1(I) collagen gene indicated that stimulation of gene transcription was involved in the increased expression of matrix mRNA. Gelatinolytic activity in conditioned media was decreased at 24 and 48 h of stretch/relaxation, in association with a significant decrease in levels of mRNA for matrix metalloproteinase-2 (68-72 kD type IV collagenase) occurring within 6 h of stretch/relaxation. In contrast, expression of tissue inhibitor of metalloproteinase-2 was increased within 12 h of stretch/relaxation. Stretch/relaxation increased immunoreactive TGF-beta at 48 but not 12 h. TGF-beta1 mRNA levels remained unchanged during the initial 12 h of stretch/relaxation, but were significantly elevated at 48 h, and no differences in TGF-beta bioactivity could be detected in conditioned media for up to 12 h of stretch/relaxation. These findings demonstrate that in glomerular mesangial cells, repeated cycles of stretching and relaxation lead to matrix accumulation by stimulating production of extracellular matrix and decreasing activity of degradative enzymes. The observed induction of TGF-beta1 suggests a role in matrix accumulation occurring in response to continued mechanical deformation.

Animals↗
PubMed1996

Forensic applications of genetic polymorphisms detected in human body fluids (urine, semen and blood).

The development of a new genetic marker with forensic usefulness is difficult and costly work, but it is necessary. We discovered several new markers detected in urine, semen and blood. In particular, deoxyribonuclease I-polymorphism is one of the most useful markers for practical purposes, since it has a well-balanced gene frequency, high concentration in body fluids, stability against severe conditions, and easy and accurate detectability.

Blood Chemical Analysis↗
PubMed1996

Gene transfer to the retina of rat by liposome eye drops.

Gene delivery to the intraocular tissues of the retina is hampered by complicated surgical interventions to administer the gene. Here we showed that instillation as eye drops of an expression plasmid vector for beta-galactosidase gene carried by the specific kinds of liposomes could transfer the gene to the retinal ganglion cells of rat, without causing any inflammation. This non-surgical, convenient way for gene delivery to the retina would facilitate the development of treatment for various intraocular diseases.

Animals↗
PubMed1996

Improvement of pharmacokinetics and antitumor activity against human hepatoma cell line by using adriamycin-entrapped stealth liposomes.

Preferential accumulation in the reticuloendothelial system is one of the major obstacles to the use of liposomes as a drug carrier for targeting therapy. To reduce their uptake, ganglioside GM1 was introduced into the components of conventional liposomes that had been used in our targeting experiments. Two types of such liposomes were prepared. Tissue distribution studies on Adriamycin entrapped in both types of liposomes clearly indicated that the uptake of Adriamycin by liver and spleen decreased to the level comparable to that of free Adriamycin administration. By contrast, the level of Adriamycin in the serum remains high, and some increase was observed in the accumulation to the tumor. Furthermore, Adriamycin in these liposomes, which were conjugated with anti-alpha-fetoprotein (AFP) antibody, inhibited the growth of AFP-positive human hepatoma Li-7 more efficiently than free Adriamycin or Adriamycin in antibody-conjugated conventional liposomes.

Animals↗
PubMed1996

Quantitative determination of amlodipine in serum by liquid chromatography with atmospheric pressure chemical ionization tandem mass spectrometry.

A sensitive and specific liquid chromatographic method coupled with tandem mass spectrometry was developed for the quantification of amlodipine in human and rat serum, which is a dihydropyridine derivative with calcium antagonist activity. An atmospheric pressure chemical ionization interface was used as the ion source and the analysis was performed in the selected reactive monitoring (SRM) mode. Deuterated amlodipine was used as the internal standard, and serum samples were treated with diethyl ether extraction prior to analysis. Serum levels in the range 0.014-7.2 ng ml-1 were measured accurately by this method, and the lower limit of quantitation (LOQ) was 0.014 ng ml-1 using 1 ml of human serum. The accuracy was within 7% of the expected values. The intra-assay precision was less than 3% and the inter-assay precision was less than 6%. The method was applied to a pharmacokinetic study of amlodipine in rats, in which the measurable range was 0.14-72 ng ml-1 using 0.1 ml of serum because of a limitation on the sample volume.

Amlodipine↗
PubMed1996

pH gradient electrophoresis of basic ribonucleases in sealed slab polyacrylamide gels: detection and inhibition of enzyme activity in the gel.

A simple method for the separation and specific detection of basic ribonucleases (RNases) was developed. The separation was achieved by polyacrylamide gel electrophoresis in a pH gradient generated by a carrier ampholyte (Pharmalyte 8-10.5) and arginine. In order to prevent interference from atmospheric carbon dioxide, the pH gradient was formed in sealed vertical gel slab. Human nonsecretory-type RNase, bovine pancreatic RNase A, and other basic proteins could be resolved without expensive equipment or complicated procedures. For activity detection after electrophoresis a zymogram technique was applied, using dry agarose film containing ethidium bromide plus RNA as substrate. This approach affords two advantages: (i) Basic RNase activities can be detected within 15 min, even in crude materials. The sensitivity is better than 0.5 ng of purified human nonsecretory-type RNase. (ii) An inhibition test of RNase activities in the gel, using human placental-type RNase inhibitor, can be performed.

Alkalies↗
PubMed1996

Alpha-2-HS-glycoprotein (AHSG) polymorphism in semen and saliva.

Polymorphism of alpha-2-HS-glycoprotein (AHSG) was demonstrated in human semen and whole saliva samples by thin-layer polyacrylamide gel isoelectric focusing (IEF) and immunoblotting. Although the seminal AHSG IEF patterns were found to differ from those of plasma AHSG from the corresponding donors, incorporation of Nonidet P-40 into the IEF gel (pH 4.2-4.9) enabled us to phenotype seminal AHSG correctly. Salivary AHSG, however, exhibited IEF patterns similar to those of the corresponding plasma AHSG. By treating the samples with neuraminidase, it was possible to determine the AHSG types using 2-5 microL semen and 50-100 microL whole saliva samples. The AHSG types determined separately in 47 sets of semen, whole saliva, urine and plasma samples from the same donors correlated perfectly with each other. AHSG typing could, therefore, provide an additional discriminant characteristic in the forensic examination of semen and saliva samples.

Blood Proteins↗
PubMed1996

Successful deoxyribonuclease I (DNase I) phenotyping from a small piece of used sock.

The forensic application of the DNase I polymorphism for individualization of used socks is described. We devised a technique that combines a simple extraction method, including a partial purification step, using a Phenyl-Sepharose CL-4B column, isoelectric focusing and activity staining, for DNase I typing from socks. As a result, DNase I types were determined from socks kept at room temperature for a month or more in all of the samples tested. The DNase I types determined from socks exactly matched those determined from corresponding sweat and urine samples. By contrast, AB0 groupings could not be determined from these samples, using the conventional serological method. Therefore, we have shown that the DNase I polymorphism is the first genetic marker found to be well suited for individualization of used socks.

ABO Blood-Group System↗
PubMed1996

Possible involvement of RGD (Arg-Gly-Asp)-containing extracellular matrix proteins in rat growth plate chondrocyte differentiation in culture.

RGD (arg-gly-asp)-containing proteins have been shown to be components of cartilage matrix. In the present study, the role of interactions of cells with RGD-containing cartilage matrix proteins in rat costal epiphyseal chondrocyte differentiation was examined using a pelleted culture system as an in vitro model of endochondral ossification. Cell attachment assays showed the presence of integrins which mediated the binding of chondrocytes to fibronectin, a member of RGD-containing cartilage matrix proteins, in an RGD-dependent manner. In the early culture period, when chondrocytes had nonhypertrophic morphology with low levels of alkaline phosphatase, the exogenous addition of synthetic peptide GRGDSP (gly-arg-gly-asp-ser-pro) caused an increase in alkaline phosphatase levels and enlargement of chondrocytes in pelleted cultures. Treatment with GRGDSP from the early to late culture periods in association with the transition of chondrocytes from prehypertrophic to hypertrophic phenotypes followed by matrix mineralization resulted in suppression of mineral growth without significant effects on alkaline phosphatase levels or cellular morphology in the cultures. Similarly, addition of the synthetic peptide during the late culture period with the advance of cartilage mineralization suppressed mineral growth in pelleted cultures. These data indicate an important role of interactions of chondrocytes with RGD-containing cartilage matrix proteins through integrins in the regulation of epiphyseal chondrocyte differentiation in pelleted cultures.

Amino Acid Sequence↗
PubMed1996

Purification of mammalian ribonuclease using immobilized human ribonuclease inhibitor.

Affinity chromatography on immobilized ribonuclease (RNase) inhibitor was developed for purification of mammalian RNase. Human placental RNase inhibitor was conjugated to CNBr-activated Sepharose in the presence of dithiothreitol. About 80% of the immobilized RNase inhibitor was capable of binding bovine pancreatic RNase A. The bound RNase A was eluted with 3 M NaCl at pH 5.0. Two 25-kDa and 18-kDa RNases, which were obtained from human liver using a cellulose phosphate column, were bound to the immobilized RNase inhibitor and recovered in a pure and active form after treatment of the resin with p-hydroxymercuribenzoate. These enzymes were considered to be nonsecretory-type RNases with different sugar contents.

Amidohydrolases↗
PubMed1996

Malignant fibrous histiocytoma secondary to fibrous dysplasia. A case report.

A man of 50 years of age had a malignant fibrous histiocytoma secondary to asymptomatic fibrous dysplasia of the proximal femur. Radiographs showed ill-defined osteolytic changes near to the fibrous lesion which had a ground glass appearance. The histology was of a malignant fibrous histiocytoma concomitant with fibrous dysplasia. An extensive resection of the tumour was carried out and chemotherapy given, but the patient died from a liver metastasis 9 months later. The possibility of malignancy should be considered if a patient with fibrous dysplasia has any progressive symptoms.

Cell Transformation, Neoplastic↗
PubMed1996

Identification of the nucleotide substitution that generates the fourth polymorphic site in human deoxyribonuclease I (DNase I).

In addition to the three polymorphic sites responsible for protein polymorphism, a new polymorphic site has been identified in intron 7 of the human deoxyribonuclease I (DNase I) gene. Three phenotypes were observed on single-strand conformational polymorphism analysis of a 266-bp polymerase chain reaction-amplified fragment containing exon 7 and part of intron 7 of the human DNase I gene. DNA sequencing analysis demonstrated that a C-G substitution occurred at position 1978 in intron 7. This substitution was confirmed by restriction fragment length polymorphism analysis, since a new Msp1 site is created by the substitution. Population and family studies showed that the inheritance of the genotypes for DNase I C1978G polymorphism is controlled by two codominant alleles, tentatively designated DNASE1*1978C and *1978G. The gene frequencies in a Japanese population were significantly different from those in a Caucasian (German) population. The C1978G polymorphism is in linkage disequilibrium with the common DNase I protein phenotypes 1, 1-2, and 2.

Base Sequence↗
PubMed1996

The Epstein-Barr virus (EBV) alters the B cell glycolipid which is recognized by the human monoclonal antibody to i-blood group antigen.

To analyze the differentiation-related glycolipids, we have recently developed human monoclonal anti-i antibodies (mAbs) using a combination of EBV-transformation and bovine i-active glycolipid (NeuAc alpha 2-->3Gal beta 1-->4GlcNAc beta 1-->3Gal beta 1-->4GlcNAc beta 1-->3Gal beta 1-->4Glc beta 1-->1Cer)-containing liposome immune lysis assay (LILA). Using complement cytolysis with these mAbs, we found the occurrence of a surface antigen (Ag) in the EBV-negative but not in the EBV-positive cell lines. The fresh EBV infection reveals that the suppressed expression of the antigen was a result of the EBV infection. The Ag recognized with these mAbs appeared to have a very low density on the B cell lines. Unexpectedly, thin layer chromatogram (TLC)-immunostaining using the mAbs revealed that the major immunoreactive substance in the EBV-negative B cell lines was an extremely minor glycolipid that was distinct from the i-active glycolipid however, this was not the case in the EBV-positive B cell lines.

Antibodies, Monoclonal↗
PubMed1996

Method development for the determination of cefdinir and its related substances by high-performance liquid chromatography.

The validation of the HPLC method used for the determination of cefdinir and its related substances is described. The developed method was specific and stability-indicating and provided a linear response with concentration. The system and method precision, expressed as relative standard deviations, were not greater than 1%, and the reproducibilities within and between laboratories were acceptable for the assay method. The procedure can quantitate related substances greater than approximately 0.05% of the principal cefdinir peak.

Calibration↗