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Biomedical subjects

T Kanazawa

Publications and source records attributed to T Kanazawa.

At least 73 records · Page 4Linked to original sources
PubMed1998

Reproducibility of 99Tcm-MAG3 clearance in normal volunteers with the two-sample method: comparison with 131I-OIH.

The aim of this study was to evaluate the reproducibility of 99Tcm-mercaptoacetyltriglycine (99Tcm-MAG3) clearance and to compare it with that of 131I-orthoiodohippurate (131I-OIH), which is widely used in clinical practice. Twelve young healthy volunteers with a mean age of 23.4 years (range 19-28) were enrolled in the study. The investigations were repeated at an interval of 1 month under similar physiological conditions. Each volunteer received a simultaneous injection of 99Tcm-MAG3 and 131I-OIH that was commercially available in an already labelled form. Blood samples were obtained at 44 and 104 min post-injection. Clearance values were calculated using the two-sample method. The mean (+/- S.D.) change from the first to the second measurement was -7.1 +/- 11.1% for 99Tcm-MAG3 and 1.7 +/- 13.6% for 131I-OIH. There were no significant differences between the first and the second measurements of 99Tcm-MAG3 and 131I-OIH clearance, respectively. 99Tcm-MAG3 clearance was shown to be very similar to that of 131I-OIH in healthy volunteers.

Adult↗
PubMed1998

The effects of radix Salviae miltiorrhizae on lipid accumulation of peroxidized low density lipoprotein in mouse peritoneal macrophages--lipid analysis and morphological studies.

Mouse peritoneal macrophages were incubated in DMEM with pox-LDL and Rradix Salviae Miltiorrhizae (RSM) to investigate the effects of RSM on the internalization of peroxidized low density lipoprotein (pox-LDL) by using lipid analysis and electron microscopy. Lipid peroxide (LPO) concentrations were increased slightly in the medium after incubation of macrophages with normal LDL (n-LDL), while decreased significantly in the media after incubation of macrophages with pox-LDL. In the three groups with pox-LDL, it could be found that there was a dose-dependent decrease of concentrations of LPO and total cholesterol (TCH) in the two RSM groups, and the decrease in the two RSM groups was much greater than in the group without RSM. RSM accelerated a more decrease of LPO than cholesterol contents in the media containing pox-LDL. The ultrastructural studies also showed that RSM induced the accumulation of lipid droplets in the cytoplasm of mouse peritoneal macrophages. The results suggested that RSM could accelerate the phagocytosis and degradation of pox-LDL by macrophages.

Animals↗
PubMed1998

[A case of refractory pulmonary fistula, managed with bronchoscopic therapy using occluding spiral embolus].

We report a successful case of bronchoscopic therapy using occluding spiral embolus and fibrin glue for refractory pulmonary fistula. A 22-year-old female underwent left lower lobectomy for giant bulla of the lung. Air leakage began 6 days after lobectomy. Closing alveolar fistula was performed 12 days after first operation. Relapsing air leakage began 4 days after second operation. Bronchography revealed a fistula from left B1+2c. The insertion of embolus through bronchofiberscope, following administration of fibrin glue, was performed to close the fistula. This method is effective for refractory pulmonary fistula.

Adult↗
PubMed1998

[14C-oxalate autoradiographic studies on distribution of oxalate and calcium oxalate crystal fixation in rat kidney].

To elucidate the intrarenal distribution of oxalate and to reveal the first site of calcium oxalate crystal fixation along the nephron, we carried out 14C-oxalate renal microautoradiography by the thaw mount method 30, 60 and 90 min after intravenous administration of 14C-oxalate, in normal rats and in hyperoxaluric rats fed a vitamin B6-deficient diet for 4 and 9 weeks. In normal rats, radioactivity was observed in the entire kidney area at 30 min after the injection and at 90 min there was radioactivity only in the papilla, where radioactivity appeared in the parenchyma, mamely the epithelial cells of collecting ducts and the surrounding interstitial tissue. In hyperoxaluric rats, microautoradiograms showed the spotted deposits of 14C-oxalate in both renal papilla and medulla. In 600 x magnification of the autoradiograms, most of the deposits were detected in the epithelial cells of collecting ducts and the surrounding interstitial tissue. These deposits were identified by a polarizing microscope and X-ray microanalysis as crystal deposits of calcium oxalate. These results indicated that oxalate remained for an extended period of time in the epithelial cells of collecting ducts and in the surrounding interstitial tissue in renal papilla, and the calcium oxalate crystals fixed to the same tissue was the first step in the development of calcium oxalate stones.

Animals↗
PubMed1998

[Combined chemotherapy with low-dose cisplatin, tegafur and uracil in a case with neck recurrence of laryngeal cancer].

The patient was a 60-year-old man with progressive neck recurrence of laryngeal squamous cell carcinoma. As a previous treatment, he had undergone irradiation (primary: 60 Gy; neck: 45 Gy) after two cycles of neoadjuvant chemotherapy (cisplatin 100 mg/m2 daily; day 1:5-fluorouracil 1,000 mg/m2 daily; day 1-5) and planned neck dissection. For a neck recurrence, he had received five cycles of low-dose cisplatin (5 mg/body daily: day 1-5) with tegafur and uracil (600 mg/body daily: day 1-7) every week. As an outpatient, he then received ten cycles of low-dose cisplatin (10 mg/body daily: day 3, 6) with tegafur and uracil (600 mg/body daily: day 1-7) every week. The size of the tumor did not decrease with the above chemotherapy, but no remarkable growth of the cancer was seen, and no toxic effect of the chemotherapy was observed. He continued his job for 30 weeks just as before he had fallen sick. Chemotherapy of low-dose cisplatin with tegafur and uracil was suggested to be useful for the patient with recurrent laryngeal squamous cell carcinoma.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1997

Modification of histidine 5 in sarcoplasmic reticulum Ca2+-ATPase by diethyl pyrocarbonate causes strong inhibition of formation of the phosphoenzyme intermediate from inorganic phosphate.

Sarcoplasmic reticulum vesicles were modified with diethyl pyrocarbonate (DEPC), a histidine-modifying reagent. Phosphoenzyme formation from Pi in the Ca2+-ATPase (reversal of hydrolysis of the phosphoenzyme intermediate) was almost completely inhibited by this modification. Tight binding of F- and Mg2+ and high affinity binding of vanadate in the presence of Mg2+, both of which produce transition state analogs for phosphoenzyme formation from the magnesium-enzyme-phosphate complex, were also inhibited. Formation of the phosphoenzyme from acetyl phosphate in the forward reaction was only weakly inhibited, but hydrolysis of the phosphoenzyme was strongly inhibited. The enzyme was protected by tight binding of F- and Mg2+ or by high affinity binding of vanadate in the presence of Mg2+ against the DEPC-induced inhibition of phosphoenzyme formation from Pi. The enzyme was also protected by tight binding of F- and Mg2+ against the DEPC-induced inhibition of phosphoenzyme hydrolysis. Peptide mapping of the tryptic digests, detection of peptides containing DEPC-modified histidine by UV absorption at 240 nm, amino acid analysis, sequencing, and mass spectrometry showed that His-5 was a single major residue protected by the above transition state analogs against the modification with DEPC. These results indicate that modification of His-5 with DEPC is responsible for the DEPC-induced inhibition of phosphoenzyme formation from Pi and of phosphoenzyme hydrolysis and suggest that His-5 is located in or very close to the catalytic site in the transition state for phosphoenzyme formation from the magnesium-enzyme-phosphate complex and is likely involved in the catalytic process of this reaction step.

Animals↗
PubMed1997

Inhibitory effects of spinorphin, a novel endogenous regulator, on chemotaxis, O2- generation, and exocytosis by N-formylmethionyl-leucyl-phenylalanine (FMLP)-stimulated neutrophils.

To characterize the inflammatory effect of spinorphin, an endogenous peptide purified from bovine spinal cord, its effects on chemotaxis, O2- generation, and exocytosis by N-formylmethionyl-leucyl-phenylalanine (FMLP)-stimulated human neutrophils (PMNs) in vitro were examined. At 10 microM, spinorphin significantly inhibited chemotaxis by FMLP-stimulated PMNs. Spinorphin at 100 microM also inhibited both O2- generation and exocytosis of beta-glucuronidase and collagenase by FMLP-stimulated PMNs. The mechanisms by which spinorphin inhibits these PMN functions were examined further. Spinorphin markedly suppressed the binding of FML[3H]P to its receptor on PMNs, as observed in a binding assay. However, other neuropeptides that were examined (angiotensin II and substance P) had no effect on FML[3H]P binding, suggesting the possibility that spinorphin plays a specific role in the inhibition of the binding between FMLP and its receptor. The suppression of FMLP binding also caused a decrease of the FMLP-induced intracellular calcium concentration [Ca2+]i, which acts as a second messenger leading to PMN functions. These results suggest that spinorphin may be a new endogenous inflammation-regulatory peptide that modulates the interaction of FMLP with its receptor.

CD13 Antigens↗
PubMed1997

Modification of arginine-198 in sarcoplasmic reticulum Ca2+-ATPase by 1,2-cyclohexanedione causes inhibition of formation of the phosphoenzyme intermediate from inorganic phosphate.

Sarcoplasmic reticulum vesicles were modified with 1,2-cyclohexanedione (CHD), a specific arginine-modifying reagent, in sodium borate (pH 8.0 or 8.8). Phosphoenzyme formation from Pi in the Ca2+-ATPase (reversal of hydrolysis of the phosphoenzyme intermediate) was almost completely inhibited by the modification with CHD. Tight binding of F- and Mg2+ and high affinity binding of vanadate in the presence of Mg2+, either of which produces a transition state analog for phosphoenzyme formation from the magnesium-enzyme-phosphate complex, were also markedly inhibited. In contrast, phosphoenzyme formation from acetyl phosphate in the forward reaction was unaffected. The enzyme was appreciably protected by tight binding of F- and Mg2+ or by high affinity binding of vanadate in the presence of Mg2+, but not by the presence of 20 mM MgCl2 alone or 150 mM Pi alone, against the CHD-induced inhibition of phosphoenzyme formation from Pi. Peptide mapping of the tryptic digests, detection of peptides containing CHD-modified arginyl residues with Girard's reagent T, sequencing, and mass spectrometry showed that Arg-198 was a single major residue protected by tight binding of F- and Mg2+ against the modification with CHD. These results indicate that modification of Arg-198 with CHD is responsible for at least a part (the portion reduced by the transition state analogs) of the CHD-induced inhibition of phosphoenzyme formation from Pi and suggest that Arg-198 is located in or close to the catalytic site in the transition state for phosphoenzyme formation from the magnesium-enzyme-phosphate complex.

Amino Acid Sequence↗
PubMed1997

An enzyme-linked immunosorbent assay for detecting proteolytic activity of hepatitis C virus proteinase.

An ELISA method for the quantitation in vitro of HCV serine proteinase activity was developed. A peptide substrate, Ac-Gly-Glu-Ala-Gly-Asp-Asp-Ile-Val-Pro-Cys-Ser-Met-Ser-Tyr-Thr-Trp-Thr-L ys (biotin) -OH (Sub-1), was hydrolyzed by a recombinant NS3 proteinase fused with maltose binding protein (MBP-NS3) into a product with a free amino moiety at the N-terminus. The product was immobilized, and the amino moiety was analyzed by digoxigenin labeling followed by immunological reaction with anti-digoxigenin-alkaline phosphatase conjugate and then the colorimeteric reaction. This method is suited for the high throughput screening of inhibitors, and the screening can be accelerated by automatic operation.

Amino Acid Sequence↗
PubMed1997

Stoichiometry of phosphorylation to fluorescein 5-isothiocyanate binding in the Ca2+-ATPase of sarcoplasmic reticulum vesicles.

In an attempt to establish the stoichiometry of phosphorylation in the Ca2+-ATPase of sarcoplasmic reticulum (SR) vesicles, phosphorylation by ATP (or Pi) or labeling by fluorescein 5-isothiocyanate (FITC) was performed with the SR vesicles under the conditions in which almost all the phosphorylation sites or FITC binding sites are phosphorylated or labeled. The resulting vesicles were solubilized in lithium dodecyl sulfate and then the Ca2+-ATPase was purified by size exclusion high performance liquid chromatography. Peptide mapping and sequencing of the tryptic digest of the purified enzyme showed that Lys-515 of the Ca2+-ATPase was exclusively labeled with FITC, in agreement with the previously reported findings. The content of the phosphoenzyme from ATP (4.57 nmol/mg of Ca2+-ATPase protein) or from Pi (4.94 nmol/mg of Ca2+-ATPase protein) in the purified enzyme was approximately half the content of the FITC binding site (8.17-8.25 nmol/mg of Ca2+-ATPase protein) and also half the content of the Ca2+-ATPase molecule (9.06 nmol/mg of Ca2+-ATPase protein) calculated from its molecular mass (110,331 Da). These results show that there is one specific FITC binding site per molecule of the Ca2+-ATPase (in agreement with the previously reported findings) and that the stoichiometry of phosphorylation to FITC binding is approximately 0. 5:1.0. All the above findings lead to the conclusion that only half of the Ca2+-ATPase molecules present in the SR vesicles can be phosphorylated. FITC binding completely inhibited the ATP-induced phosphorylation before the binding reached its maximum level. This finding indicates that FITC preferentially binds to a part of the Ca2+-ATPase molecules and that this binding is primarily responsible for the inhibition of phosphorylation, suggesting an intermolecular ATPase-ATPase interaction.

Adenosine Triphosphate↗
PubMed1997

Extracardiac direct total cavopulmonary connection.

We report a successful extracardiac direct total cavopulmonary connection without prosthetic materials performed in a 3-year-old boy with tricuspid atresia, infundibular pulmonary stenosis, and normally positioned great arteries. The transected pulmonary trunk was bought down posterolaterally with respect to the right atrium and was anastomosed end-to-end with the inferior vena cava.

Child, Preschool↗
PubMed1997

Oxidized LDLs but not native LDLs augment Ba2+ currents through L-type Ca2+ channels of the A7r5 smooth muscle-derived cell line.

The whole-cell patch-clamp method was used on A7r5 smooth muscle-derived cell line, and Ba2+ currents through Ca2+ channels were recorded. The A7r5 cells showed voltage-dependent, long-lasting Ba2+ currents which were markedly inhibited by nifedipine (10 microM). The magnitude of the maximum Ba2+ current (IBa(max)) was augmented by an application of dbcAMP (1 mM), but not affected by TPA (80 nM). Noradrenaline (NA) at 100 microM caused an increase in the IBa(max) by 19.7% in the presence of phentolamine (10 microM). This effect was cancelled by Rp-cAMPs (10 microM). In the presence of propranolol (10 microM), NA tended to reduce the IBa(max). Application of Ox-LDLs at 100 microg protein/ml caused an increase in the IBa(max) by 15.7%, whereas native LDLs did not change the IBa(max). Rp-cAMPs was ineffective to the Ox-LDL action on the IBa(max). In the presence of Ox-LDLs, NA augmented the IBa(max) by 21.4% in the presence of phentolamine. These results suggest that Ox-LDLs activate L-type Ca2+ channels of A7r5 cells by a mechanism independent of cAMP/PKA signalling.

Aorta↗
PubMed1997

A novel class of potent gamma-aminobutyric acid aminotransferase inhibitor, 3-(hydroxyamino)propylamine and analogues.

Hydroxyamino analogues of gamma-aminobutyric acid (GABA) were synthesized and evaluated for inhibitory activity toward gamma-aminobutyric acid aminotransferase (GABA-T). The title compound, 3-(hydroxyamino)propylamine (HPA), showed a potent inhibitory activity. The inhibition is competitive with respect to GABA and the Ki value of GABA-T for HPA is 0.4 mmol. The activity of inhibition is comparable to those of aminoxyacetic acid and valproic acid. 3-(Hydroxyaminomethyl)piperidine (3HMP), a cyclic analogue of HPA, also showed a potent inhibitory activity, whereas 3-(methoxyamino)propylamine (OMe-HPA), 3-(N-hydroxy-N-methylamino)propylamine (NMe-HPA) and 4-(hydroxyamino)piperidine (4HP) showed weak activity.

4-Aminobutyrate Transaminase↗
PubMed1997

gamma-Pyrones from Gonystylus keithii, as new inhibitors of parathyroid hormone (PTH)-induced Ca release from neonatal mouse calvaria.

New gamma-pyrones, 9'-oxopodopyrone (3) and 8-methyl-9'-oxopodopyrone (4) were isolated from the leaves of Gonystylus keithii, along with known gamma-pyrones, 10'-oxopodopyrone (1) and 8-methyl-10'-oxopodopyrone (2). These gamma-pyrones markedly inhibited the bovine parathyroid hormone (PTH)-induced Ca release from neonatal mouse calvaria in vitro. It is the first time that gamma-pyrones showed inhibitory effects on bone resorption, and these compounds may be seed compounds of new drugs for osteoporosis.

Animals↗
PubMed1997

Detection of microfilarial antigen in circulating immune complex from sera of Wuchereria bancrofti-infected individuals.

Polyethylene glycol-precipitated circulating immune complexes (CICs) from the sera of patients with Bancroftian filariasis were examined for parasite antigen content by an ELISA. Of the 227 patients, 214 were asymptomatic microfilariae carriers with microfilaremias ranging between six and 14,000/ml blood, and 13 were symptomatic patients with chronic filariasis without microfilaremia. In addition, the sera of 10 of the patients treated with diethyl carbamazine were also examined. These assays were devised using mouse monoclonal antibody raised against microfilariae of Wuchereria bancrofti. Using an acid-phase covalent-bound plate for the ELISA makes it possible to assay the antigen contents simply. Microfilarial antigens were detected from 92 (43.0%) of microfilaria (mf)-positive individuals. Furthermore, the level of antigen in CIC was correlated with mf counts from night blood Nuclepore filtration results. Antigen was not detected in CIC from patients with a variety of nonfilarial helminth infections. These findings indicate that microfilariae play an important role of CIC formation in lymphatic filariasis.

Animals↗
PubMed1997

Effects of pressor substances on low density lipoprotein peroxidation by Cu++.

To investigate whether pressor substances accelerate low density lipoprotein peroxidation by Cu++, low density lipoprotein was dialysed against physiological saline containing O-5 mumol/l CuCl2 and/or 1 mumol/l of various pressor substances. Lipid peroxide value of low density lipoprotein changed little with the addition of norepinephrine to the saline, but the addition of norepinephrine to 1 mumol/l CuCl2 accelerated the peroxidation. When low density lipoprotein was dialysed against saline with norepinephrine, epinephrine, serotonin or dopamine, there were no significant differences in the lipid peroxide values of low density lipoprotein. Although the addition of serotonin into the dialyzate did not accelerate the peroxidation of low density lipoprotein due to Cu++, the addition of norepinephrine, epinephrine and dopamine accelerated the Cu(++)-peroxidation with a significant increase in the acceleration rate starting at the 36 hour point. Thus, it is speculated that various stresses stimulating the sympathetic nervous system accelerate the peroxidation of low density lipoprotein and produce peroxidized low density lipoprotein in the blood.

Analysis of Variance↗
PubMed1997

[Fibrin glue spray treatment on the polytetrafluoroethylene graft].

An outer surface of a 4 mm polytetrafluoroethylene (PTFE) prosthesis, Gore-Tex thin-walled stretch graft, was treated by the fibrin glue spray with a 1.0 kg/m2 compressed air. The distance between the PTFE graft and a spray-nozzle was within 0.5 cm. After the treatment, an outer surface and a cross-section of the PTFE graft were examined under a scanning electron microscope. Fibrin glue mended the gap of the PTFE fibril of an outer surface and a fibrin glue layer adhered firmly to the graft. The fibrin glue spray treatment may prevent postoperative serous fluid leakage.

Aerosols↗