Biomedical subjects

M Tokuda

Publications and source records attributed to M Tokuda.

At least 145 records · Page 8Linked to original sources

PubMed1992

Evaluation of cardiac motion and function by cine magnetic resonance imaging.

Cardiac cine magnetic resonance imaging (MRI) was studied to evaluated the cardiac motion and function, and a water-stream phantom study was performed to clarify whether it was possible to quantitatively assess the valvular regurgitation flow by the size of the flow void. In normal subjects, the left ventricular (LV) epicardial apex swung up to the base only a few millimeters, and the mitral annulus ring moved about 14 mm as mean value toward the apex during systole. Those motions of mitral annulus ring may contribute to the left atrial filling. The LV longitudinal shortening and torsions were shown by the tagging method. This tagging method was the best method for estimating cardiac motions. Cardiac cine MRI using software including a modified Simpson's method program and a wall motion analysis program was useful for routine LV volumetry and wall motion analysis because it was a simple and reliable method. Our water-stream phantom studies demonstrated that it might be difficult to perform quantitative evaluation of valvular regurgitation flow by using only the size of the flow void without acquiring information relating to the orifice area.

Adult↗

PubMed1991

Isolation and sequence of rat testis cDNA for a calcium binding polypeptide similar to the regulatory subunit of calcineurin.

We have cloned and sequenced rat testis cDNAs coding for a calcium binding polypeptide similar to calcineurin beta subunit, the Ca(2+)-binding subunit of the Ca2+/calmodulin stimulated protein phosphatase. Rat testis cDNA library was screened with a monoclonal antibody Va1 raised against bovine brain calcineurin beta subunit. The deduced amino acid sequence is similar to that of human brain calcineurin beta subunit with respect to containing four putative calcium binding sites. However, distinct differences were found: 1) The cloned cDNA had six amino acids polypeptide tail at carboxy-terminal which is absent in human brain calcineurin beta subunit. This amino acids tail makes the carboxy-terminal highly hydrophilic in contrast to the human brain beta subunit which is hydrophobic at carboxy-terminal; 2) eleven amino acids at the N terminal of the cloned cDNA were completely different from the corresponding region of the brain calcineurin beta subunit.

Amino Acid Sequence↗

PubMed1991

Immunogenicity and protective effect against oral colonization by Streptococcus mutans of synthetic peptides of a streptococcal surface protein antigen.

Streptococcus mutans is known to be a major causative organism of human dental caries. A surface protein Ag with a molecular mass of 190 kDa of S. mutans (PAc) is receiving attention as an anticaries vaccine. We have recently determined the complete nucleotide sequence of the gene for PAc. In this study, four peptides were synthesized on the basis of amino acid sequence of PAc. Among these peptides, PAc(301-319) corresponding to the alanine-rich repeating amino acid region was the most strongly bound by polyclonal murine anti-rPAc antibodies. The peptide partially inhibited the binding of polyclonal anti-rPAc antibodies to rPAc. The peptide induced the proliferation of T cells from BALB/c mice immunized with rPAc. Subcutaneous immunization with PAc(301-319) or rPAc emulsified in CFA/IFA induced high serum IgG responses to rPAc and PAc(301-319). In addition, serum IgG responses to a surface protein Ag with a molecular mass of 210 kDa of Streptococcus sobrinus were elicited in mice immunized by s.c. injection with PAc(301-319) or rPAc. Intranasal immunization with PAc(301-319) coupled to cholera toxin B subunit (CTB) or with rPAc and free CTB induced high serum IgG responses to rPAc. The immunization with PAc(301-319) coupled to CTB or rPAc and free CTB suppressed the colonization of murine teeth by S. mutans. These results suggest that intranasal immunization with the peptide or rPAc may be effective for the prevention of dental caries.

Animals↗

PubMed1991

Complete nucleotide sequence of the gene for a surface protein antigen of Streptococcus sobrinus.

The complete nucleotide sequence of the gene for a cell surface protein antigen (SpaA) of Streptococcus sobrinus MT3791 (serotype g) was determined. The spaA gene consisted of 4,698 bp and coded for a protein of 170,202 Da. A putative signal peptide was found in the amino-terminal end of the protein. A potential promoter sequence and a putative Shine-Dalgarno sequence preceded the open reading frame. Two internal repeating amino acid sequences were present in SpaA. One repeating region, located in the amino-terminal region, was rich in alanine, and the other, located in the central region, was rich in proline. The molecular structure of SpaA was very similar to that of the surface protein antigen of Streptococcus mutans.

Amino Acid Sequence↗

PubMed1991

Identification of two calcineurin alpha isoforms in bovine brain by two different monoclonal antibodies.

Calcineurin (calcium- and calmodulin-stimulated phosphatase) alpha subunit purified from bovine brain was found to be composed of two polypeptides, 61 KDa (alpha 1) and 59 KDa (alpha 2). The two peptides were separated and extracted from polyacrylamide gel. The immuno-peptide mapping of the purified peptides by partial proteolysis showed that the 59-KDa polypeptide was not a degradative product of the 61-KDa polypeptide. The interaction of the enzyme with two monoclonal antibodies, Vj6 and Vd3, raised against bovine brain calcineurin revealed that the 61-KDa polypeptide was recognized by both Vj6 and Vd3, whereas the 59-KDa one was recognized only by Vj6. These results indicate that there are at least two isoforms of calcineurin alpha subunits in bovine brain.

Animals↗

PubMed1991

Mechanism of transient increase in intracellular concentration of free calcium ions in HL-60 cell differentiation induced by vitamin D3 and phorbol ester.

A promyelocytic leukemia cell line, HL-60, was induced to differentiate into monocyte-macrophage lineage cells by treatment with active vitamin D3 and phorbol esters, and into granulocyte lineage ones by retinoic acid and dimethylsulfoxide. The changes in intracellular concentration of free calcium ions ([Ca2+]i) were measured and analyzed by calcium-imaging analysis with Fura 2-AM. A significant and transient increase in [Ca2+]i was observed in active vitamin D3 and phorbol ester systems; however, no change was detected with retinoic acid and dimethylsulfoxide. This increase was due to the influx of calcium ions from outside of the cells, and L-type calcium channels were shown to mainly contribute to this influx. Protein kinase C was also shown to be involved in the increase in [Ca2+]i.

Calcitriol↗

PubMed1991

[Heterogeneity of anticardiolipin antibody].

The antibody to cardiolipin(ACA) was tested in patients with systemic rheumatic disease. The frequency of IgG ACA was 46/100(46.0%) in systemic lupus erythematosus(SLE). In other rheumatic disease, this was less than 20%. Significant correlation between the presence of IgG ACA and thrombosis and/or thrombocytopenia was found in patients with SLE. Eight sera containing high titered IgG ACA from lupus patients were selected for further inhibition study. Inhibitors were consisted of cardiolipin(CL), phosphatidyl(p-)serine, p-inositol, p-glycerol, p-ethanolamine, p-choline, ds-DNA, ss-DNA, fresh platelets(PLT)and fresh red blood cells(RBC). All sera were markedly inhibited by negatively charged phospholipids. In 4 sera(group B), there was moderate inhibition by ss-DNA, ds-DNA, PLT and RBC. In another 4 sera(group A), mild but significant inhibition was obtained by PLT alone. The number of platelet in group A was less than that in group B. There were some differences in inhibitory activity, suggesting heterogeneity of antibody to CL. It may be possible to speculate that heterogeneity of IgG ACA cause various combination of clinical features such as thrombocytopenia and thrombosis.

Abortion, Spontaneous↗

PubMed1991

[An improved method for biochemical measurement of the activity of neutrophil alkaline phosphatase and its application to myeloproliferative disorders].

The activity of neutrophil alkaline phosphatase (NAP) has been commonly measured semi-quantitatively by rating the intensity and number of positive granules on cytochemical staining. This method has been widely adopted because of quickness and simplicity. However, the scoring system, in itself, seems to have several demerits that it has poor reproducibility and has limit for expressing enhanced NAP activity. We improved previous methods for measuring biochemical activities of NAP. Our method was as quick and simple as cytochemical measurement and had more excellent reproducibility. Biochemical activities of NAP ("b-NAP"s) in extract from 2 x 10(6) neutrophils of 7 patients with polycythemia vera were about six times as high as those of 7 cases of essential thrombocythemia [144.8 +/- 33.2, 23.1 +/- 9.1 U, respectively], while NAP scores in the former showed only twice the degree of elevation of those in the latter. These observations suggest that our method can represent high NAP activity more exactly than NAP score and may be a potential tool in differentiating polycythemia vera from essential thrombocythemia.

Alkaline Phosphatase↗

PubMed1990

Insulin-like growth factor I (IGF-I) distribution in the tissue and extracellular compartment in different regions of rat brain.

The regional distribution of insulin-like growth factor I (IGF-I) was examined in the tissue and extracellular compartment of rat brain. The tissue content of IGF-I was the highest in the pituitary gland, followed by the olfactory bulb, upper brainstem, cerebellum, striatum, hippocampus, lower brainstem, and cerebral cortex. The extracellular concentration was studied by intracerebral microdialysis technique, and the highest content was found in the hippocampus, followed by the olfactory bulb, hypothalamus, cerebellum, striatum, and cerebral cortex. The tissue and extracellular contents were significantly correlated in the olfactory bulb, hypothalamus, cerebellum, striatum, and cerebral cortex. IGF-I might act by paracrine and/or autocrine regulatory mechanisms in these regions.

Animals↗

PubMed1990

Induction of differentiation of HL-60 cells by protein kinase C inhibitor, K252a.

To clarify the role of protein kinase C and protein kinase A in cell proliferation and differentiation, the effects of K252a and its derivatives (K252b, KT5720), which have different inhibitory activity to these protein kinases, on the proliferation and differentiation of HL-60 cells were investigated. The proliferation and DNA synthesis of the HL-60 cells were inhibited by K252a in a dose dependent manner. However, K252b and KT5720 which are more specific inhibitors of protein kinase C or protein kinase A, respectively, had no observable effect on cell proliferation. K252a (40nM) enhanced the differentiation of HL-60 cells induced by 1,25(OH)2D3, retinoic acid and DMSO. K252b and KT5720 did not affect 1,25(OH)2D3-induced differentiation. K252a significantly inhibited the differentiation induced by PMA. These results demonstrate that K252a but not its derivatives can function as an antitumor drug and enhancer of the differentiation induced by various inducers.

Carbazoles↗

PubMed1990

Construction of NotI restriction map of the Streptococcus mutans genome.

Streptococcus mutans and Streptococcus sobrinus are the major causative organisms of human dental caries. Pulsed-field gel electrophoresis (PFG) showed that the restriction enzyme NotI produced ten and six DNA fragments from the genomes of S. mutans strain MT8148 and S. sobrinus strain 6715, respectively. The sizes of the chromosomes of S. mutans and S. sobrinus were each estimated to be about 2200 kb. The NotI restriction map of S. mutans MT8148 genome was constructed by Southern blot analysis with probes that overlapped two adjacent NotI fragments. Several virulence-associated genes of S. mutans were placed on the NotI restriction map. In addition, unique 'fingerprints' of S. mutans chromosomal DNA digested with NotI were produced by PFG, and these may be useful for epidemiological studies.

Base Sequence↗

PubMed1990

In vivo analysis of extracellular proteins in rat brains with a newly developed intracerebral microdialysis probe.

Peptides and proteins in the extracellular space in the central nervous system were investigated in vivo using an intracerebral microdialysis probe. The molecular cut-off of the hollow fiber which was used for the probe was approximately 100 kDa. We examined recovery rates of several compounds in vitro. The recovery rates of proteins and peptides were between 7-28%, with the exceptions of substance P and insulin-like growth factor I. The recovery rates of monoamines and their metabolites were 22-40%. In in vivo studies, two major proteins with apparent molecular weights of 62 kDa and 12 kDa, and several minor proteins (28 kDa, 43 kDa, 52 kDa and 70 kDa) were detected by SDS-polyacrylamide gel electrophoresis in the dialysate from a probe implanted in the striatum of anesthetized rats. These results suggest that the newly developed, intracerebral microdialysis probe might be useful for investigating the dynamic changes of peptides and proteins in the central nervous system.

Animals↗

PubMed1990

Adipose tissues and vitamin E.

1. Vitamin E content in the adipose tissue was examined in rats with and without vitamin E deficiency. With the progression of vitamin E depletion, the more rapid decrease in tocopherol concentration was observed in brown adipose tissue (BAT) than in white adipose tissue (WAT), and the rate of decrease of tocopherol was approximately three times faster in BAT than in WAT. After the intramuscular administration of 10 mg/kg of all-rac-tocopheryl acetate twice a week for two weeks to vitamin E-deficient rats, a similar pattern of increase was observed in the tocopherol concentrations of BAT and WAT, although the rate of increase was slower in WAT than in BAT. 2. Changes of tocopherol concentration in BAT and WAT were investigated in normo-nourished rats with hyperlipemia produced by the intramuscular injection of Triton WR-1339 for 7 days. A marked increase in tocopherol concentration was observed in both BAT and WAT in the late period of hyperlipemia, with the increase being greater in WAT. 3. The fatty acid composition of adipose tissue was compared between rats with and without vitamin E deficiency. No significant differences were observed in BAT and WAT between the two groups. 4. The glucose uptake of WAT was not altered in vitamin E-deficient rats when compared with control rats.

Adipose Tissue↗

PubMed1990

[Ileocolic intussusception in a recurrent non-Hodgkin's lymphoma; report of a case].

The adult intussusception is rare. Here, we describe a case of an adult patient with ileocolic intussusception secondary to a recurrent lymphoma of the terminal ileum. The patient was a 42-year-old female, who had a history of the subtotal gastrectomy because of the primary gastric lymphoma. Eight months after the operation, she had a relapse in the abdomen and received the combination chemotherapy. She acquired the complete remission, but six months after the completion of the chemotherapy, she suffered from the right lower abdominal pain and diarrhea. Physical examination revealed a soft mass with tenderness in the right iliac fossa. Barium studies and abdominal computed tomography showed an ileocolic intussusception. At laparotomy, a 4.5 cm polypoid tumor was found in the terminal ileum and it passed through the ileocaecal valve to form an intussusception. Histologic examination disclosed the follicular lymphoma of medium-sized cell type. So far as we are aware, this is the first report of an adult patient with intussusception secondary to a lymphoma in Japan.

Adult↗

PubMed1990

[Correlation between intracellular alkaline phosphatase activities and incidence of toxic granules in neutrophilia].

We examined the intracellular alkaline phosphatase (NIAP) activities in peripheral neutrophils in 15 healthy subjects and 15 patients with inflammatory diseases, and compared them with the percentages of neutrophils with cytoplasmic toxic granules (NTG), which is thought to be induced by infection. NIAP activities were markedly increased in patients and significantly correlated with the percentages of NTG. These data indicate that measurement of NIAP activity is useful for the diagnosis of infections and/or inflammatory diseases.

Alkaline Phosphatase↗

PubMed1990

Purification and immunohistochemical study of actin in mitochondrial matrix.

Actin was purified to apparent homogeneity from the matrix of ultra-pure mitochondria of rat livers by DNase-I affinity chromatography and HPLC gel filtration. The mitochondrial actin was immunologically identified by an anti-actin antibody, and its apparent molecular weight was 43 KDa, as determined by SDS-polyacrylamide gel electrophoresis. The immunohistochemical study revealed the localization of the mitochondrial actin in the matrix space and on the internal surface of inner membrane. The actin fraction eluted from a DNase-I column by KCl-EGTA solution underwent polymerization and bundling in vitro.

Actins↗

PubMed1990

[Intracellular alkaline phosphatase activities in myelodysplastic syndrome].

We examined the intracellular alkaline phosphatase (NIAP) activities in peripheral neutrophils in 15 normal controls, 4 patients with myelodysplastic syndrome, and 4 with chronic myeloid leukemia. NIAP activities were decreased in myelodysplastic syndrome in comparing to normal controls (p less than 0.01). These data suggest that measurement of NIAP activity is useful for supporting a diagnosis of myelodysplastic syndrome.

Alkaline Phosphatase↗

PubMed1989

Demonstration of different regional distributions of calcineurin subunits using monoclonal antibodies.

Immunohistochemical localizations of calcineurin subunits A (60 KDa) and B (20 KDa) were examined in a rat brain using subunit specific monoclonal antibodies. The immunoreactivity of the subunit A was abundant in the hippocampus, in the striatum, and in the thalamus, but weak in the neocortex. On the contrary, the immunoreactivity of the subunit B was more abundant in the cortex, and it was more ubiquitous than subunit A. The distribution of subunit A in the rat brain very well agreed with that of zinc, which is an intrinsic metal ion and a potent inhibitor of calcineurin phosphatase.

Animals↗