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Biomedical subjects

T Akizawa

Publications and source records attributed to T Akizawa.

At least 19 recordsLinked to original sources
PubMed1995

Effects of membrane characteristics on cytokine production by mononuclear cells in regular haemodialysis patients.

To determine the relationship between haemodialysis and cytokine production, the effects of solute permeability and biocompatibility of dialysis membranes on cytokine production by mononuclear cells were evaluated. Eighteen stable haemodialysis patients were divided into three groups and underwent haemodialysis under the same conditions except for the dialysis membrane used. Endotoxin in dialysate remained at concentrations of 10 pg/ml or less throughout the study. Haemodialysis was performed for a total of 6 weeks. Group A used a regenerated cellulose low-flux membrane during the first 2 weeks, a regenerated cellulose high-flux membrane during the next 2 weeks and a polymethylmethacrylate (PMMA) high-flux membrane during the last 2-week period, while Group B used the regenerated low-flux cellulose membrane first, followed by the PMMA low-flux membrane and PMMA high-flux membrane. Group C used the same membrane throughout the 6-week study period. Peripheral mononuclear cells were sampled before, 30 min after the start and upon completion of the final dialysis session and incubated for 18 h in the presence and absence of lipopolysaccharide (LPS) stimulation. Tumour necrosis factor-alpha (TNF-alpha), interleukin-1 beta (IL-1 beta) and IL-6 concentrations in the supernatant and cell lysate were determined. In all groups, cytokine production just before the final dialysis using each membrane was comparable regardless of the presence or absence of LPS stimulation. LPS-stimulated TNF-alpha production decreased significantly 30 min after the start of dialysis compared to the predialysis baseline. This change was not affected by the type of membrane used.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Relative hypoparathyroidism in hemodialysis patients.

To clarify the incidence and contributing factors of hypoparathyroidism in a hemodialysis (HD) population, 224 patients undergoing maintenance HD were investigated. They were divided into 4 groups according to their high-sensitive parathyroid hormone levels: extra-high (EH) group > 420,000 pg/ml; high (H) group 20,000-420,000 pg/ml; moderate (M) group 4,500-20,000 pg/ml; low (L) group, < 4,500 pg/ml. In group L, a 25-mg/kg deferoxamine (DFO) infusion test was undertaken to estimate aluminum (Al) accumulation. The distribution in each group was 42, 35, 12, and 11% for groups L, M, H and EH, respectively. Group-L patients were relatively older than those of the other groups. Diabetes was seen in 20% of group-L patients, as opposed to no diabetes in groups H and EH. Among the 22 diabetics, 82% were in group L. 70% of group-L patients showed a less than 50-micrograms/l Al increment after the DFO infusion test. Bone mineral density (BMD) did not differ between the groups with relative hypoparathyroidism (RHP=L) and background-matched non-RHP, either at the initiation of HD or the recent period, and the changes in BMD were comparable between the 2 groups. These results suggest that a considerable number of HD patients show RHP. Diabetes, but not Al accumulation, was considered to be one of the predisposing factors of RHP. Though the outcome of RHP will be aplastic bone disease (ABD) in HD patients, the clinical significance of ABD has not been fully evaluated. Further studies are required to clarify the precise mechanisms of RHP and the significance of ABD.

Adult↗
PubMed1994

Finding of primitive polyamine toxins in the venom of a joro spider, Nephila clavata.

A series of joro spider toxins, novel polyamines sharing a common moiety of 2,4-dihydroxyphenylacetyl cadaverine, have been identified using various bioassays, such as inhibition of a glutamatergic transmission and insecticidal activity. In this paper, we tried to chemically find still unknown polyamine toxins in the venom of a joro spider, N. clavata, by several analytical methods based on the characteristics of the common moiety. An aqueous extract from 3000 venoms was separated by preparative high performance liquid chromatography (HPLC). The polyamine toxins were detected by monitoring the fluorescence produced in an on-line reaction of o-phthalaldehyde with amino groups and UV absorption of the phenol group. Two compounds in minute quantity were purified and analyzed by gas-liquid chromatography (GC) and HPLC, which we specifically developed for the simultaneous determination of amino acids and polyamines of the toxins. Judging from the constituents of the hydrolysate by GC and HPLC and the molecular weights determined by fast atom bombardment mass spectrometry, the two compounds were estimated to be N-(2,4-dihydroxyphenylacetyl-L-asparaginyl)-N'- (3-aminopropyl-beta-alanyl) cadaverine and N-(4-hydroxyphenylacetyl-L-asparaginyl)-N'-(3-aminopropyl-beta-ala nyl) cadaverine. These compounds were small in content and molecular weight compared with hitherto known toxins. Both were presumed to be biochemically primitive toxins and were named spidamine and joramine, respectively.

Animals↗
PubMed1994

Structures of novel bufadienolides in the eggs of a toad, Bufo marinus.

In this paper, we report chemical structures of five compounds including four novel polyhydroxylated cardiac steroids in the eggs of a toad, Bufo marinus. These cardiac steroids were purified by high-performance liquid chromatography, and their structures were determined to be 11 alpha,19-dihydroxy-telocinobufagin (I), 11 alpha-hydroxytelocinobufagin (II), 11 alpha,19-dihydroxymarinobufagin (III), 11 alpha-hydroxymarinobufagin (IV) and 19-hydroxytelocinobufagin (V) on the basis of spectral data of nuclear magnetic resonance and mass spectroscopy. All the five compounds showed biological activity, as tested by inhibition of Na+,K(+)-ATPase activity and of [3H]ouabain binding to the receptor on Na+,K(+)-ATPase. This is the first finding of bufadienolides as cardiac steroids in animal eggs.

Animals↗
PubMed1994

[Anticoagulant effect of a single bolus injection of parnaparin sodium (LHG) on a hemodialysis model in dogs].

Hemodialysis was performed on dogs, following intravenous bolus injections of LHG at dosage levels of 50, 100 and 200 IU/kg and heparin at the levels of 100 and 200 IU/kg. LHG exerted dose-dependent anticoagulant effects and prolonged the hemodialysis time, compared to heparin with similar anti-Xa activity. When LHG was administered, the half-life of plasma anti-Xa activity was longer than that of heparin at similar anti-Xa activity. LHG prolonged the activated partial thromboplastin time (APTT) linearly and dose-dependently. However, the prolongation was much less than that of heparin, and the anticoagulant activity of LHG continued even after the APTT returned to the value before LHG administration. When LHG was administered, whole blood Xa activated coagulation time (XCT) and plasma Xa activated coagulation time (PXCT) were prolonged in a significantly greater degree compared to APTT. Therefore, XCT and PXCT were considered to be appropriate parameters for monitoring LHG. In the groups administered with LHG at 100 and 200 IU/kg, where hemodialysis could be continued for 8 hr, the tissue factor pathway inhibitor (TFPI) activity in the plasma tended to show a sustained increase. These findings suggested the possibility that not only the antithrombin III dependency mechanism but also the TFPI mechanism contributed to a longer LHG hemodialysis duration compared to heparin administration.

Animals↗
PubMed1994

Bile salts of the toad, Bufo marinus: characterization of a new unsaturated higher bile acid, 3 alpha,7 alpha,12 alpha,26-tetrahydroxy-5 beta-cholest-23-en-27-oic acid.

The bile salts present in gallbladder bile of the toad, Bufo marinus, were found to consist of a mixture of bile alcohol sulfates and unconjugated bile acids. The major bile alcohol was 5 beta-bufol; 5 alpha- and 5 beta-cholestane-3 alpha,7 alpha,12 alpha, 26-tetrols occurred as the minor bile alcohols. Bile acids of Bufo marinus were cholic acid, allocholic acid, 3 alpha,7 alpha,12 alpha-trihydroxy-5 alpha- and 5 beta-cholestan-26-oic acids, 3 alpha,7 alpha,12 alpha-trihydroxy-5 alpha- and 5 beta-cholest-23-en-26-oic acids, 3 alpha,7 alpha,12 alpha, 26-tetrahydroxy-5 beta-cholestan-27-oic acid, and a C27 bile acid which has not been previously described. By chromatographic behavior, mass spectral data, and identification of the products of catalytic hydrogenation and ozonolysis, the structure of the new higher bile acid was elucidated as 3 alpha,7 alpha,12 alpha,26-tetrahydroxy-5 beta-cholest-23-en-27-oic acid. The bile salt pattern of Bufo marinus closely resembles that of Bufo vulgaris formosus, except for the absence of 3 alpha,7 alpha,12 alpha-trihydroxy-5 beta-cholest-22-ene-24-carboxylic acid, the major bile acid of the latter toad.

Animals↗
PubMed1994

Effect of dialysis membranes and ACE inhibitor on bradykinin levels during hemodialysis.

The effects of dialyzer membrane material and concurrent angiotensin converting enzyme (ACE) inhibitor on plasma bradykinin levels during hemodialysis were investigated. Six patients treated with an ACE inhibitor and 6 other patients not receiving an ACE inhibitor underwent three consecutive hemodialysis sessions with an AN-69 dialyzer and three sessions with a polysulfone dialyzer. The sequence of dialyzers (AN-69 followed by polysulfone or the reverse) was determined randomly. With the AN-69 membrane dialyzer, the plasma bradykinin level at the dialyzer outlet was significantly greater than that at the dialyzer inlet at 5 min but not at 10 min after initiation of dialysis, whereas no significant difference between inlet and outlet bradykinin concentrations was observed at either time with the polysulfone membrane dialyzer. The changes in plasma bradykinin level in patients with concurrent ACE inhibitor did not differ from those found in patients without ACE inhibitor. These results indicate that the AN-69 membrane stimulates bradykinin production at the initial stage of hemodialysis in patients with as well as without concurrent ACE inhibitor. Further study is necessary to clarify the exact role of ACE inhibitor in elevation of bradykinin levels during hemodialysis.

Anaphylaxis↗
PubMed1994

[Clinical usefulness of visual analog scale for assessment of dyspnea at rest in patients with chronic respiratory diseases].

To evaluate the validity and clinical usefulness of the visual analog scale (VAS) for the measurement of dyspnea at rest, we employed the 150 mm VAS in 29 chronic respiratory disease patients who were clinically stable, and repeated the measurement 4 weeks and 8 weeks later for the evaluation of reproducibility. For the 8-week period, the individual medical treatments remained generally unchanged in all patients. Two patients were excluded from the study due to infection and pneumothorax. Dyspnea at rest was detected on VAS in 23 patients at the first measurement. The VAS measurement was 23.9 +/- 28.4 (mean +/- SD) mm at the first time, 22.0 +/- 23.1 mm at the 4th week, and 22.4 +/- 26.0 mm at the 8th week. There was no significant change among the three measurements. Twenty among the 23 patients with VAS indicative of dyspnea at rest were categorized into grades 4 and 5 of the Fletcher dyspnea category. However, the intensity of dyspnea was distributed widely within each Fletcher category. These results lead to the conclusion that VAS shows good reproducibility over a period of as long as 8 weeks and that VAS measurements can reveal patient-to-patient individual differences in dyspnea intensity which cannot be detected by the Fletcher dyspnea category. We propose that measuring dyspnea at rest using VAS is a useful method to obtain a valid clinical parameter.

Adult↗
PubMed1993

Recent progress in management of secondary hyperparathyroidism of chronic renal failure.

Recent progress in cellular and molecular biology has had a great impact on our understanding of parathyroid hormone-vitamin D physiology and of the pathogenesis of secondary hyperparathyroidism in chronic renal failure and made possible the development of new therapeutic approaches for management of bone disease in dialysis patients. Management of parathyroid hyperplasia by calcitriol pulse therapy is one example. Suppression of parathyroid hyperfunction by other vitamin D analogues was also proposed, and some of these analogues are now under clinical trial. Further, percutaneous ethanol injection into hyperplastic parathyroid glands under ultrasonographic guidance has become the choice practical procedure under certain clinical settings and can be an effective alternate to surgical parathyroidectomy. In this article, we review selected and pertinent progress in the pathogenesis and management of secondary hyperparathyroidism and parathyroid hyperplasia, major causes of morbidity in chronic dialysis patients, emphasizing the important contributions made by laboratory research and critical clinical observations.

Animals↗
PubMed1993

Nafamostat mesilate: a regional anticoagulant for hemodialysis in patients at high risk for bleeding.

107 hemodialysis patients at high risk for intradialytic bleeding due to previous surgery or active bleeding from other sites were treated with nafamostat mesilate (FUT-175; FUT) as hemodialysis anticoagulant for 2 weeks. In contrast to heparin. FUT prolonged clotting times only in the extracorporeal circuit. Clotting times were not prolonged even at the conclusion of the treatment, and bleeding from the puncture site after removal of the needle was shorter than with heparin. The exacerbation of bleeding by hemodialysis was noted in only 21 out of 573 hemodialysis procedures (3.7%), and 134 of 145 hemodialysis procedures (92.4%) with active bleeding were successfully completed without increasing the bleeding. Adverse effects of FUT were noted in only 6 cases (5.6%) or 1.2% of HD procedures. These results indicate that FUT is a very useful anticoagulant for HD, especially in patients with high risk of bleeding.

Aged↗
PubMed1993

Role of uremic and endothelial factors in the development of beta 2-microglobulin amyloidosis.

To clarify the importance of uremic and endothelial factors in the development of beta 2-microglobulin (beta 2m) amyloidosis, in vitro evaluations were carried out using cultured synoviocytes and synovial tissues. Synoviocytes of patients with chronic renal failure were cultured with media containing uremic or normal serum. In cultures with uremic serum, greater proliferation of synoviocytes and stronger expression of CD68, beta 2m, interleukin 1 beta (IL-1 beta) and tumor necrosis factor alpha (TNF alpha) on synoviocytes were observed, compared with those containing normal serum. Uremic serum stimulated greater production of IL-1 beta and TNF alpha than normal serum (P < 0.05 for IL-1 beta, P < 0.01 for TNF alpha). Addition of supernatant of endothelial cell culture to medium containing uremic serum significantly accelerated production. After a three month culture of uremic synovial tissue, embedded in 3% type 1 collagen gel with uremic serum, beta 2m-positive 10 nm fibrils were recognized around the synoviocytes. In culture with uremic serum plus supernatant of endothelial cell culture, positive Congo red staining was noted. These findings indicate that uremic serum plays a significant role in the development of synovial beta 2m amyloidosis and that endothelial cell-derived factors contribute to the formation of beta 2m amyloid.

Amyloidosis↗
PubMed1993

Bcl-3, a member of the I kappa B proteins, has distinct specificity towards the Rel family of proteins.

Expression of the bcl-3 gene is demonstrated to be elevated in some B-cell chronic lymphocytic leukemias with a chromosomal translocation, t(14;19)(q32;q13.1). Bcl-3 protein has seven tandem ankyrin repeats that are also found in I kappa B proteins, inhibitors of Rel/NF kappa B transcription factors. In this paper, we demonstrate that Bcl-3 is a member of I kappa B family of proteins with a novel specificity. Bcl-3 preferentially associates with the p50 of NF kappa B, and the nuclear localization signal of p50 is required for this association. Bcl-3 inhibits the DNA-binding activity of p50 homodimers but not that of p50-p65 heterodimers. Transient transfection experiments revealed that appropriate expression of Bcl-3 results in inhibition of the function of p50 homodimers but not that of p50-p65 heterodimers, whereas pp40 and I kappa B gamma inhibit the function of both p50 homodimers and p50-p65 heterodimers. These studies suggest that Bcl-3 could modulate the transcription in a way different from pp40 and I kappa B gamma.

B-Cell Lymphoma 3 Protein↗
PubMed1992

Interaction of HTLV-1 Tax1 with p67SRF causes the aberrant induction of cellular immediate early genes through CArG boxes.

Tax1 of human T-cell leukemia virus type 1 (HTLV-1) is a transcriptional activator for viral gene expression and is also a transforming protein through inducing the expression of several cellular genes under the control of mitogenic signals. We identified the CArG boxes as a Tax1-responsive cis-acting element for the cellular immediate early genes c-fos, egr-1, and egr-2. Using a chimeric protein consisting of the CArG-binding factor p67SRF and the heterologous DNA-binding domain of a yeast transcription factor GAL4, we demonstrated that Tax1 activates the transcriptional activity of p67SRF through the GAL4-binding site. The carboxy-terminal half of p67SRF, which lacks domains for DNA-binding, dimerization, and ternary complex formation with p62TCF, was sufficient for the activation by Tax1. Tax1 produced in Escherichia coli bound p67SRF in vitro. The complex formation in vivo was also indicated by the finding that the acidic activation domain of VP16, by fusion to p67SRF, can complement the transcriptional activation function of a mutant Tax1 in trans. Thus, Tax1 activates CArG-mediated transcription without mitogenic signals through interaction with a CArG-binding factor, p67SRF. This must be one of the primary steps by which Tax1 causes aberration in growth control of the infected cells.

Base Sequence↗
PubMed1992

Isolation of substance P binding protein from rat brain.

Substance P (SP) binding protein of rat brain was solubilized by digitonin. The solubilized proteins were then purified by sequential gel filtration, concanavalin A lectin Sepharose, and SP-affinity chromatography. The calculated molecular weight of this purified SP binding protein was 76-74 kDa on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The rabbits were immunized with the purified protein and resulting polyclonal anti-sera were tested. The immune serum significantly inhibited [3H]SP binding to the 3-[(3-cholamidopropyl)dimethylammonio]-1-propane sulfonate solubilized membrane fractions from rat brain, whereas pre-bleed antiserum failed to inhibit the binding. This polyclonal antibody also inhibited the activity of 45Ca influx into astroglioma cells stimulated by SP, but does not inhibit that stimulated by histamine. Furthermore, this polyclonal antibody recognized the 76-74 kDa band as assessed by Western blotting. These data strongly suggest that this polyclonal antibody could recognize a part of the natural SP receptor site.

Animals↗
PubMed1992

Nafamostat as anti-coagulant for membrane plasmapheresis in high bleeding risk patients.

Nafamostat mesilate (NM), an ultrashort-acting multi-enzymatic inhibitor, is a useful anti-coagulant in high bleeding risk patients needing hemodialysis. We applied NM as a membrane plasmapheresis (MP) anti-coagulant in patients with high bleeding risk. Eleven patients, the majority with hepatic failure and active hemorrhagic foci or severe bleeding diathesis, could be treated with MP 22 times under anti-coagulation by 20-40 mg/h/NM by continuous infusion without any trouble. Celite-activated coagulation time (CCT) at the plasma separator inlet and outlet was adequately prolonged during MP, but CCT in systemic blood showed no prolongation throughout the procedure, because NM was rapidly inactivated. There was no observable blood coagulation in the extracorporeal circuit including the plasma separator. No adverse reaction or exacerbation of hemorrhage was noted throughout the MP. NM thus appears to be a useful and safe anti-coagulant not only for hemodialysis but also for MP in high bleeding risk patients.

Adolescent↗