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Biomedical subjects

M Hirata

Publications and source records attributed to M Hirata.

At least 577 records · Page 32Linked to original sources
PubMed1986

Immunoglobulins inside Schistosoma japonicum eggs from the livers of mice.

Using fluorescent antibody techniques, immunoglobulins (Ig's), mainly IgG class, were detected inside Schistosoma japonicum eggs lodged in mouse liver. Ig's were observed as a focal pattern between the miracidium and the eggshell during early infection (5-7 wk), particularly in lightly infected mice (20 cercariae). With advancement of time of infection (8-18 wk), a diffuse pattern of staining over the miracidial body developed and became predominant. The diffuse pattern of staining could be observed in the eggs taken from heavily infected mice (50 cercariae), during early stage. Eggs showing the focal pattern in a restricted area appeared to be morphologically intact, whereas eggs showing the diffuse pattern exhibited some types of eggshell destruction. We conclude that the focal pattern reflects disintegration of eggs in the initial stage and the diffuse pattern in the advanced stage. This spatial relationship between Ig's and eggs is discussed in relation to destruction of eggs.

Animals↗
PubMed1986

[Phase II study on oral administration of MCNU (ranomustine) tablet. Hanshin Cooperative Study Group on Hematological Disorders].

A phase II study of MCNU tablet has been performed on 70 patients with hematological disorders including mostly myeloproliferative disorders. MCNU tablet was given p.o. at a dose of 50 mg daily for 2-6 days (total 100-300mg) as one course with average intervals of 3 to 5 months or more for patients responding to this drug. The effective rates were 72% in 18 patients with chronic myelogenous leukemia, 88% in 25 patients with polycythemia vera and 68.5% in 19 patients with essential thrombocythemia. Side effects of MCNU tablet were nausea and vomiting (31%) which had a dose-dependent relationship, mild liver dysfunction (5%) and elevation of BUN and creatinine (2%) which were not serious. The results were almost comparable to those of the phase II study of MCNU given intravenously.

Administration, Oral↗
PubMed1986

[Augmentation by serrapeptase of tissue permeation by cefotiam].

Cefotiam (CTM) is a new cephalosporin with a broad spectrum of activity against both Gram-positive and Gram-negative microorganisms. Cephalosporins are widely used for prophylaxis of infections in patients undergoing thoracotomy. Augmentation by serrapeptase on tissue permeation of CTM was examined in 35 thoracotomy patients with lung cancer. The subjects were divided into two groups according to the method of the administration of CTM. Group I consisted of 17 subjects, each of whom received a single dose of 2 g of CTM alone by an instillation for 30 minutes. Group II consisted of 18 subjects, each of whom received a combination of CTM and serrapeptase; serrapeptase was given 2 tablets (10 mg) each time for three times/day until the day before surgery, and then CTM was administered by the same procedure. The following results were obtained: Individual difference was observed for the permeation of CTM into tissues. Pathologic differences also affected the permeation. Nevertheless, the CTM levels in pulmonary tissues reached about a half of those in the blood in both the single dose group and the combination group, hence sufficient concentrations exceeding MIC80 for main microorganisms that caused infections in the lung were obtained. The concentrations of CTM in inflammatory tissues have showed lower levels than those of normal tissues in both CTM single dose and the combination groups. Decrease of blood flow volume may have contributed to the reduction in levels of CTM in the inflammatory tissues. The ratio of the concentration of the drug in pulmonary tissues to that in the blood was 29.1 +/- 2.5% in the single dose group, and 44.2 +/- 6.0% in the combination group, the latter showing quite a significant increase (P less than 0.05). Combined administrations of CTM and serrapeptase deserves more trials in the case when surgical treatments of the lung are performed. An antiinflammatory effect of serrapeptase in the respiratory system is expected, and in addition, the combined use of CTM and serrapeptase should stimulate permeation of the antibiotic into tissues.

Adult↗
PubMed1985

Spin trapping of a free radical intermediate formed during microsomal metabolism of hydrazine.

A radical formed during oxidative metabolism of hydrazine in rat liver microsomes was spin-trapped with alpha-phenyl-t-butylnitrone. The trapped species was identified as hydrazine radical by comparison of its ESR parameters and mass spectrum with those of the adduct formed during CuCl2 catalyzed oxidation of hydrazine. The requirement for oxygen and NADPH in the microsomal oxidation and the occurrence of a typical binding spectrum by difference spectroscopy suggest the involvement of the participation of the cytochrome P-450 enzyme system in the formation of hydrazine radical which must be a precursor of diimide during microsomal oxidation of hydrazine.

Animals↗
PubMed1985

Dependence on Ca2+ of the activities of phosphatidylinositol 4,5-bisphosphate phosphodiesterase and inositol 1,4,5-trisphosphate phosphatase in smooth muscles of the porcine coronary artery.

The activities of phosphatidylinositol 4,5-bisphosphate (PIP2) phosphodiesterase (PDE) and inositol 1,4,5,-trisphosphate (IP3) phosphatase in the particulate and cytosol fractions prepared from porcine coronary artery smooth muscles were examined using 32P-labelled PIP2 and IP3 as substrates, respectively. The activity of PIP2 PDE, as assessed from the production of IP3, in the cytosol fraction was about 10-fold higher than that in the particulate fraction. In the absence of MgCl2, the activity of PIP2 PDE in both fractions showed no causal relation to the free Ca2+ concentration in the physiological range of 10(-7)-10(-5) M, but was enhanced remarkably by 10(-4) M free Ca2+. The addition of 1 mM-MgCl2 to the assay medium markedly inhibited the activity of PIP2 PDE in both fractions in the presence of free Ca2+ (10(-8)-10(-5) M). In the absence of MgCl2, 10(-5)M-acetylcholine (ACh) produced IP3, and this action was blocked by 3 X 10(-6) M-atropine. The ACh-induced activation of PIP2 PDE ceased in the presence of 1 mM-MgCl2; however, the reactivation occurring on the addition of 10 microM-guanosine 5'-[gamma-thio]triphosphate did not depend on the free Ca2+ concentrations (10(-7)-10(-5)M). The activities of IP3 phosphatase, determined from decrease in the amount of IP3 in the particulate and cytosol fractions, had much the same potency in both fractions. The activity of IP3 phosphatase in the cytosol fraction was enhanced by MgCl2 in a concentration-dependent manner, the maximal value occurring at 1 mM-MgCl2, and was also enhanced in the presence of physiological concentrations of free Ca2+ (10(-7)-10(-6) M). These findings suggest that the activation of PIP2 PDE which occurs with application of ACh in the presence of guanine nucleotides and 1 mM-MgCl2 is independent of the free Ca2+ concentration, and that the hydrolysis of IP3 by phosphatase increases, depending on the concentration of free Ca2+.

Acetylcholine↗
PubMed1985

An intramolecular cross-linkage of lysozyme. Formation of cross-links between lysine-1 and histidine-15 with bis(bromoacetamide) derivatives by a two-stage reaction procedure and properties of the resulting derivatives.

Hen egg white lysozyme was treated at pH 5.5 with four bifunctional reagents, bis(bromoacetamide) derivatives [BrCH2CONH(CH2)nNHCOCH2Br, 1-n, n = 0, 2, 4, and 6], to alkylate His-15 monofunctionally. The excess bifunctional reagent was then removed, and the pH was raised to 9.0 to allow the other end of the reagent molecule to react. The shortest reagent (1-0) gave no intramolecularly cross-linked lysozyme derivative but only histidine-15-modified lysozyme monomer and intermolecularly cross-linked lysozyme dimer. However, the reagents with longer arms (1-2, 1-4, and 1-6) gave lysozyme derivatives cross-linked intramolecularly between the nitrogen at epsilon 2 of His-15 and the epsilon-amino group of Lys-1 without formation of any other intramolecularly cross-linked lysozyme derivative. These results are consistent with our previous proposal that lysozyme has a small hydrophobic pocket that binds small molecules in the direction from His-15 to Lys-1 [Yamada, H., Uozumi, F., Ishikawa, A., & Imoto, T. (1984) J. Biochem. (Tokyo) 95, 503-510]. The thermal stabilities of three cross-linked lysozymes thus obtained were investigated in 0.1 M acetate buffer containing 3 M guanidine hydrochloride at pH 5.5. All derivatives were stabilized but to different degrees. The derivative cross-linked with 1-4 was most stabilized (2.3 kcal/mol), but the derivatives cross-linked with the reagents both shorter (1-2) and longer (1-6) than 1-4 were less stabilized (both 1.6 kcal/mol).(ABSTRACT TRUNCATED AT 250 WORDS)

Acetamides↗
PubMed1985

Plasminogen activator activity of cultured endothelial cells derived from canine coronary vessel and human umbilical artery and vein.

The present study was undertaken to determine which cells participate in plasminogen activator (PA) release from the vascular wall. Canine coronary vessel was confirmed to release PA when various agents were administered in perfusion experiments. Endothelial cells from the coronary vessel were then isolated and cultured for 2 days. PA activity was observed in lysates of the cultured cells, and the medium used for the cultivation was found to contain little PA activity. This suggests that the endothelial cells participate in PA release from the vascular wall. In addition, the PA synthesis was also studied in cultured endothelial cells from human umbilical artery and vein. Both contained little PA activity, indicating that vascular endothelial cells may vary in PA synthesis and release according to the vessel.

Animals↗
PubMed1985

Immunocytochemical localization of gut-associated circulating anodic antigen in Schistosoma japonicum.

The localization of the gut-associated circulating anodic antigen in Schistosoma japonicum adults was revealed by means of the immunofluorescence and a peroxidase-anti-peroxidase method with the electron microscope. The reaction sites were confined to amorphous material in the cecal lumen. The cecal lumen generally was infolded with lamellae. The antigenic material appeared to be secreted by the rough endoplasmic reticulum, probably through the Golgi apparatus, into the lumen. Observations of male and female worms showed that there was a clear difference between the sexes in antigen concentration. The thick epithelium of the female worm, with well-developed cisternae on the endoplasmic reticulum, produced a lot more antigen than the male. Positive staining with ruthenium red confirmed that the antigenic material was a negatively charged polysaccharide as had been previously reported.

Animals↗
PubMed1985

The induction of chromosome condensation in tsBN2, a temperature-sensitive mutant of BHK21, inhibited by the calmodulin antagonist, W-7.

The induction of premature chromosome condensation (PCC) in tsBN2 cells, a temperature-sensitive (ts) mutant of BHK21/13 which shows PCC at the non-permissive temperature, was almost completely inhibited by 40 microM W-7, an antagonist of calmodulin. The mitotic phosphorylation of histone H1 and H3 was also inhibited by W-7. W-5, a chlorine-deficient analogue of W-7 and which interacts weakly with calmodulin, did not inhibit the induction of PCC, even at a dose of 80 microM. The content of calmodulin in tsBN2 cells was increased by a temperature shift to 40.5 degrees C. All these results suggested that calmodulin is required for the chromosome condensation.

Animals↗
PubMed1985

Roles of Ca2+ on the inositol 1,4,5-trisphosphate-induced release of Ca2+ from saponin-permeabilized single cells of the porcine coronary artery.

The release of Ca2+ from the intracellular store site, as induced by inositol 1,4,5-trisphosphate, was studied in relation to free Ca2+ concentrations or amounts of stored Ca2+ in smooth muscle cells. The maximal Ca2+ release induced by inositol 1,4,5-trisphosphate was observed when the amount of Ca2+ in the store site was about 50% of the maximal capacity of the Ca2+ storage, and when the extravesicular free Ca2+ concentration was less than 1.5 X 10(-6) M. The Ca2+ release induced by inositol 1,4,5-trisphosphate was accelerated by ATP and 5'-adenylylimidodiphosphate (AMPPNP), but not by ADP and AMP. This inositol 1,4,5-trisphosphate-induced Ca2+ release appeared to be specific for intracellular Ca2+ store sites (mainly sarcoplasmic reticulum), and this Ca2+ release was not apparent in the sarcolemmal fraction.

Adenosine Diphosphate↗
PubMed1985

Increase in Ca2+ permeability of intracellular Ca2+ store membrane of saponin-treated guinea pig peritoneal macrophages by inositol 1,4,5-trisphosphate.

Inositol 1,4,5-trisphosphate (InsP3) releases Ca2+ from the non-mitochondrial Ca2+ store site of various types of cells. To study the mechanisms of the Ca2+ release from the store site, the effect of InsP3 on the passive Ca2+ release and influx, and the active Ca2+ uptake in the presence of oxalate, was examined using saponin-treated guinea pig peritoneal macrophages. InsP3 stimulated the passive Ca2+ release and influx. Although InsP3 slightly inhibited the active Ca2+ uptake in the presence of oxalate, it seems unlikely that the Ca2+ release by this agent is caused by the inhibition of the Ca2+ uptake, because the addition of apyrase or hexokinase (which removes ATP within 30 s, so that no more Ca2+ can be accumulated) or vanadate (which inhibits the Ca2+ uptake) resulted in very slow release of Ca2+. These results suggest that the Ca2+ permeability of the Ca2+ store membrane is increased by InsP3. InsP3 did not cause an increase in the Ca2+ permeability of phospholipid vesicles (liposomes), indicating that this agent may bring about Ca2+ release by a specific effect on the physiologically relevant Ca2+ channels or carriers in the non-mitochondrial Ca2+ store site. The passive Ca2+ release by InsP3 was enhanced by ATP and an unhydrolyzable ATP analogue, 5'-adenylyimidodiphosphate, but not by ADP or AMP. The passive Ca2+ release by InsP3 was observed even at 0 degree C.

Adenosine Triphosphate↗
PubMed1985

A role for inositol 1,4,5-trisphosphate in the initiation of agonist-induced contractions of dog tracheal smooth muscle.

To elucidate the role of inositol 1,4,5-trisphosphate (Ins-P3) in the initiation of agonist-induced contraction of the smooth muscle cells of the dog trachea, we investigated the effects of acetylcholine (ACh) on the concentrations of Ins-P3, phosphatidylinositol-4,5-bisphosphate (PI-P2) or phosphatidic acid (PA). The effects of Ins-P3 on the Ca2+ stored in the smooth muscle cells were also studied in saponin-permeabilized smooth muscle cells. A half maximal or maximal Ca2+ accumulation into the cells was observed in the dispersed single, smooth muscle cells treated by saponin, in free Ca2+ concentrations of 4.6 X 10(-7) or 5 X 10(-5)M, respectively. The ATP-dependent Ca2+ accumulation was maximal at 0.63 nmol/10(5) cells. Effects of Ins-P3 on stored Ca2+ were observed at a free Ca2+ concentration of 3.7 X 10(-7)M, which induces about half maximal ATP-dependent Ca2+-accumulation. Ins-P3 released the Ca2+ accumulated by ATP, in a dose-dependent manner. About 40% of the total Ca2+ was released following application of 3 microM Ins-P3. The release of stored Ca2+ induced by application of Ins-P3 was followed by its re-uptake into the smooth muscle cells. Thus, the stored Ca2+ was repeatedly released with repetitive applications of Ins-P3. Application of ACh (10(-5)M) to the dog trachea stimulated the production of Ins-P3 in the soluble fraction and 10s after this application, the relative amount of Ins-P3 was 290% of the control value. 6 Concomitantly, ACh (10- 5 M) either reduced or increased the contents ofphosphatidyl inositol 4,5-biphosphate (PI-P2) or phosphatidic acid (PA) in the lipid fraction ofthe smooth muscle cells to 60% or to 350% of the control value, respectively, thereby indicating that ACh stimulates the phosphodiesteric hydrolysis of PI-P2. 7 5-Hydroxytryptamine (5-HT; 10- 5M) also reduced or increased the contents of PI-P2 or PA to 80 or to 200% of the control values, respectively. However, neither histamine (10-5M), in the presence or absence of cimetidine (10-5M), nor prostaglandin F2 alpha. (PGF2 alpha. 1O-7 M) showed any effect on the contents of PI-P2 or PA in the lipid fraction of the smooth muscle cells. 8 These results indicate that in muscle cells of the dog trachea, Ins-P3 may play the role ofintracellular second messenger in the initiation of ACh or 5-HT-induced contraction, but not in the case of histamine or PGF2 alpha-induced contraction.

5-Hydroxytryptophan↗
PubMed1985

Lack of tuberculin activity of synthetic peptides.

We synthesized an octapeptide, H-Asp-Gly-Gly-Ser-Glu-Ser-Glu-Gly-OH, and a hexadecapeptide, H-Asp-Gly-Gly-Ser-Glu-Ser-Glu-Gly-Lys-Asn-Gly-Ser-Gln-Met-Arg-Leu-OH, which corresponded to amino acids 61 to 68 and 61 to 76, respectively, of the amino acid sequence of a crystalline protein reported to be tuberculin active. Authenticity and purity of the synthesized peptides were confirmed by high-pressure liquid chromatography, amino acid analysis, mass spectrometry, and protein sequencer analysis. Tuberculin activity of the synthesized peptides was examined in guinea pigs sensitized with Mycobacterium tuberculosis or Mycobacterium bovis BCG and in tuberculin-positive healthy humans. Neither the octa- nor the hexadecapeptide was as active as tuberculin skin-test antigen.

Animals↗