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Biomedical subjects

H Mihara

Publications and source records attributed to H Mihara.

At least 145 records · Page 8Linked to original sources
PubMed1984

Interaction of fibrinolytic activity between the tracheobronchial secretion and circulating blood of rats.

In order to clarify the origin and release mechanism of plasminogen activator in the tracheobronchial secretion of rats, electrophoretic analysis of the secretion and studies on the effects of certain vasoactive drugs on the activator activity in the secretion were carried out. From the results of electrophoretic analysis of the tracheobronchial secretion in non-treated rats, protease inhibitor composed of glycoprotein was not contained in the secretion in contrast to the circulating blood, but a protein of low molecular weight like albumin in the circulating blood was contained in the secretion. Furthermore, after injection of noradrenalin, the blood pressure was temporarily elevated and the fibrinolytic activity of the euglobulin fraction in the circulatory blood was also increased. Subsequent to this elevation of fibrinolytic activity in the circulating blood, the fibrinolytic activity in the tracheobronchial secretion increased. Based on these results, it is suggested that the increase of fibrinolytic activity in the circulating blood was due to increased release of plasminogen activator from the vascular wall, and the increased fibrinolytic activity of the tracheobronchial secretion was caused by a consequent increased transudation of plasminogen activator from the circulating blood into the tracheobronchial lumen.

Animals↗
PubMed1984

[Mathematical simulation of the blood coagulation system].

The Blood coagulation system was converted to a mathematical model which was described using differential equations. The calculated output patterns of the mathematical model against various input stimulations were compared with results of in vitro assay. The simulated results of (1) Hemophilia A, (2) anticoagulation effect of antithrombin III and (3) anticoagulation effect of heparin corresponded to the results of in vitro assay and clinical reports. However, the simulated result of (4) anticoagulation effect of synthesized arginine derivative No. 805 (MD-805) did not correspond to the results of in vitro assay. Therefore, a new series simulation of MD-805 was done, supposing that MD-805 had an inhibitory activity not only on coagulation factor IIa but also VIIa. The new simulation pattern closely resembled the results of in vitro assay. From these facts, it was theoretically indicated that MD-805 also has an inhibitory activity on VIIa.

Adult↗
PubMed1984

A thiol protease inhibitor released from cultured human malignant melanoma cells.

A thiol protease inhibitor (TPI) was found in culture media of human malignant melanoma cells (Bowes) at 1.5 to 2.3 units/day/flask (full sheet, 75 sq cm). This amount well exceeded that for cultured nonmalignant cells (human fetal lung fibroblasts). In the intracellular region of the melanoma cells, TPI activity was localized mainly in the cytosol fraction. The difference in specific activities between the intracellular and extracellular TPI and the TPI accumulation in the culture media indicated that cultured melanoma cells release TPI. Partial purification and characterization of the TPI by column chromatography using Sephadex G-150, papain-Sepharose, and Sephadex G-50, followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, revealed two distinct TPIs with molecular weights of 56,000 and 9,800 to 10,800. The latter (main) TPI had a high specificity for thiol proteases and was heat stable (60 degrees for 60 min), like previously reported normal human TPIs. The inhibitor, however, differed from normal human TPIs in that it had a lower molecular weight than any normal TPI, was unable to inhibit bromelain, and exhibited a mosaic pattern; namely, the low-molecular-weight TPI resembled liver-type TPI but the pH stability curve resembled serum-type TPI. The thiol protease, cathepsin B, was not detected in culture media of this human melanoma cell line.

Cell Line↗
PubMed1984

Cyclic peptides. XVI. Syntheses of AM-toxin I analogs containing a lower or higher homolog of the component L-2-amino-5-(p-methoxyphenyl)pentanoic acid residue.

In order to investigate the influence of the side-chain length at position 3 of AM-toxin I (cyclic tetradepsipeptide) on necrotic activity for apple leaf, two analogs of AM-toxin I, [L-2-amino-4-(p-methoxyphenyl)butanoic acid]-AM-toxin I and [L-2-amino-6-(p-methoxyphenyl)hexanoic acid]-AM-toxin I, were synthesized by the conventional method. Spectra of 1H-n.m.r., u.v. and CD of the analogs were similar to those of natural or synthetic AM-toxin I. The toxic activities of the analogs for apple leaf, however, were weak, indicating that the exact side-chain length at position 3 must be one of the important factors for the induction of the activity. The interaction between AM-toxin I and a possible receptor on apple leaf is discussed.

Circular Dichroism↗
PubMed1983

Acid stable protease inhibitor in ascites of ovarian carcinoma.

In patients with ovarian tumors, a novel protease inhibitor which is very stable in acid (AS-PI, acid stable protease inhibitor) was identified in the ascites and tumor fluid as well as in the urine and plasma. The highest AS-PI activity was observed in the tumor fluid of ovarian carcinomas (10.7 +/- 2.3 U/ml), followed by the ascites of ovarian carcinomas (8.2 +/- 4.2 U/ml). There was a significant difference in activity of the tumor fluid and ascites between malignant and benign tumors (p less than 0.005, p less than 0.05, respectively). The same antigenicity of AS-PI fractionated from ascites of ovarian carcinomas to urinary trypsin inhibitor was identified by double immunodiffusion and neutralization techniques. It migrated in the serum albumin fraction on immunoelectrophoresis. By gel filtration, the AS-PI in the ascites of ovarian carcinomas showed a molecular weight of 70000-80000. Two active components with molecular weights of 61300 +/- 2100 and 73300 +/- 2500 were detected by SDS polyacrylamide gel electrophoresis.

Chromatography, Gel↗
PubMed1983

Activation of plasma fibrinolysis after intrarectal administration of high molecular weight urokinase and its derivative.

Following intrarectal administration of high molecular weight urokinase (molecular weight 53,000; 124,000 IU/mg protein) and its functionally active heavy chain (molecular weight 31,000; 212,000 IU/mg protein) to mice, activation of plasma fibrinolysis was observed. The plasma levels of pyro-Glu-Gly-Arg-pNA amidolysis and euglobulin fibrinolytic activities reached a maximum (43.4 +/- 5.3 nmol/ml and 10.8 +/- 9.4 mm2/0.03 ml, respectively) at 1-2 h after the administration of 300 IU of either enzyme per mouse, and thereafter, both activities declined slowly. Urokinase absorption into the plasma was further confirmed from the immunoreactivity of plasma enzymes isolated by affinity chromatography to each anti-urokinase serum.

Animals↗
PubMed1983

Multiple molecular forms of acid-stable plasmin inhibitor derived from human urinary trypsin inhibitor.

It was found that cyanogen bromide (BrCN) treatment of the highly purified human urinary trypsin inhibitors (H-UTI; specific activity 1,897 U/mg protein, and L-UTI; specific activity 1,850 U/mg protein) readily produced new plasmin inhibitors with almost no loss of UTI activity. Five multiple forms of chemically cleaved inhibitors (UTIB-I, UTIB-II, UTIB-III, UTIB-IV and UTIB-V) could be isolated from BrCN-treated L-UTI by isoelectric focusing and gel filtration. These inhibitors were very acid-stable and their isoelectric points (pI) were 4.5, 4.6, 4.9, 5.1 and 6.4, respectively. The molecular weights by SDS-polyacrylamide gel electrophoresis were almost the same at about 23,000 +/- 3,000. Although these inhibitors showed both anti-plasmin and anti-trypsin activities, much higher anti-plasmin/anti-trypsin activities were observed in the cleaved inhibitors than in the parent UTI. They competitively inhibited human plasmin with Ki values of 3.0-4.1 X 10(-8) mol/l (H-D-Val-Leu-Lys-pNA substrate).

Antifibrinolytic Agents↗
PubMed1983

Localization of fibrinolytic activity in ovulation of the rat follicle as determined by the fibrin slide method.

The localization and changes of fibrinolytic activity during the process of ovulation were investigated by the fibrin slide method. In regular estrous cycle rats, fibrinolytic activity first appeared in the external area of the follicle wall (stigma) at 12 hr before ovulation. No activity was noted in the follicular cavity at this time. A peak of activity was seen at 2 hr before ovulation. After ovulation, the activity decreased markedly. The activity was completely inhibited on fibrin slides to which 10(-2) M trans-aminomethyl-cyclohexane carboxylic acid had been added. No activity was observed on plasminogen-free fibrin slides. These results suggest that fibrinolytic activity is one of the important factors involved in the rupture of the mature follicle wall, and that the fibrinolytic activity is due to plasminogen activator activity.

Animals↗
PubMed1983

Substrate specificity of tissue plasminogen activator and urokinase as determined with synthetic chromogenic substrates.

Three different synthetic chromogenic substrates )H-glutamylglycyl-L-arginine-p-nitroanilide (S-2227), pyro-glutamyl-glycyl-L-arginine-p-nitroanilide (S-2444), and H-D-isoleucyl-L-prolyl-L-arginine-p-nitroanilide (S-2288] were investigated for use in the measurement of plasminogen activator activity with high molecular weight urokinase (H-UK), low molecular weight urokinase (L-UK), and tissue plasminogen activator (TPA). The three substrates were hydrolyzed by both TPA-type and UK-type plasminogen activator. As regards the amidolytic activity of S-2227, TPA exhibited a weaker amidolytic activity, and L-UK a stronger activity. In the case of the amidolytic activity of S-2444, no great difference between the three activators was observed in terms of Vmax. As regards the amidolytic activity of S-2288, L-UK exhibited a stronger activity, and TPA a weaker activity. It is suggested that the molecular size of the synthetic chromogenic substrate was too small when compared to natural substrate (fibrin), and therefore that fibrin-binding sites around the catalytic site in TPA are not recognized.

Chromogenic Compounds↗
PubMed1983

Control of Arthus tonsillitis by the administration of an antiplasminic agent.

Previous reports have shown that fibrinolytic activity was increased in the circulatory blood of rabbits with Arthus tonsillitis. In this study, t-AMCHA was administered intravenously to rabbits, in order to clarify its role as an antiplasminic agent in the control of Arthus tonsillitis. First, to establish the proper method of administration of t-AMCHA and the quantity to be administered, a preliminary estimation was made of the requisite concentration of t-AMCHA in the circulating blood and tonsillar tissue. Then macroscopic observations and histopathological studies were performed on the tonsils of rabbits with Arthus tonsillitis after t-AMCHA administration at various doses. Finally, after injection of the antiplasminic agent, estimations were made of the plasma fibrinolytic activity in the blood of the rabbits under study. It was decided that administration of t-AMCHA at 3-hourly intervals could maintain a constant concentration of the substance in the tonsillar tissue. The marked hyperaemia and bleeding which were observed macroscopically and histopathologically at 1-2 days after the onset of tonsillitis, disappeared from the parenchyma of the tonsils and pharyngeal tissue surrounding the tonsils in the group receiving regular injections of t-AMCHA at 3-hourly intervals. After estimating certain parameters of the fibrinolytic system in the blood, it was found that fibrinolytic activity decreased and whole plasmin was not consumed as a result of the administration of t-AMCHA during the early stage of tonsillitis. The process of Arthus tonsillitis can thus be controlled by the administration of the antiplasminic agent.

Animals↗
PubMed1983

Production of plasminogen activator in a melanoma cell line.

A melanoma cell line (Bowes) was found to produce plasminogen activator even on its growing phase, and the rate of plasminogen activator production was rather constant. The production of plasminogen activator was proportional to the cell number. Morphologically, no specific features for plasminogen activator production were seen. Plasminogen activator was observed in the lysate of this cell line only when the cell number was large. The extracellular plasminogen activator activity was higher than the intracellular plasminogen activator activity, suggesting the existence of a secretion mechanism for the plasminogen activator.

Cell Count↗
PubMed1983

The role of plasminogen activator in ovulation.

The role of plasminogen activator in ovulation was investigated using the inhibitor, trans-aminomethylcyclohexane carboxylic acid (t-AMCHA). In the regular cycle rat, the plasminogen activator activity of the follicles increased from the diestrus to the estrus phase. In the latter phase, a proteolytic enzyme which was not inhibited by t-AMCHA appeared. After ovulation, the plasminogen activator activity decreased. When ovulation was induced in immature rats by pregnant mare serum gonadotrophin and human chorionic gonadotrophin, remarkable fibrinolytic activity appeared in the ovaries immediately before ovulation. When t-AMCHA was given in the ovulation-induced rats, the fibrinolytic activity of the ovaries was suppressed, the number of ovulated ova decreased and the timing of ovulation was delayed. When t-AMCHA solution was given to rats in the proestrus phase, ovulation was almost completely suppressed, but aprotinin solution exerted no effect on ovulation. These results suggest that plasminogen activator is a key enzyme in ovulation, and that the chain reaction from plasminogen activator to proteolytic enzyme (including collagenase) is of greater importance than that of plasminogen activator to plasmin.

Animals↗
PubMed1983

Studies on proactivator from the paranasal mucous membrane in chronic sinusitis.

We succeeded in differentiating the proactivator (PA) in tissue extract of paranasal mucous membrane with chronic sinusitis by the gel filtration technique. Furthermore, the results demonstrated that PA in the tissue extracts of the paranasal mucous membrane with chronic sinusitis and antrochoanal polyp was unrelated to the antigenicity of plasminogen. In particular, it was clarified that the tissue extract of antrochoanal polyp as a source of PA was not related to the antigenicity of plasminogen.

Antigen-Antibody Complex↗
PubMed1983

The detection of fibrinogen (or FgDP)-protamine sulphate complex in vitro and in the circulating blood.

In order to clarify the pathophysiological significance of the fibrinogen (FgDP)-protamine complex, the interaction between fibrinogen and protamine sulphate was studied in vitro and in vivo. Using the electrophoretic technique, an attempt was made to determine whether the complex could be detected in vitro and in the circulating blood. From the present studies, it has been clarified in in vitro experiments that the slower mobility of two peaks on immunoelectrophoresis represented a complex of protamine sulphate and fibrinogen (FgDP). Furthermore, the peak of slower mobility on crossed immunoelectrophoresis appeared in the circulating blood of a rabbit receiving administration of excess protamine sulphate. That is, in vivo experiments showed that a complex of protamine sulphate and fibrinogen (FgDP) could be detected in the circulating blood.

Animals↗
PubMed1982

Determination of alpha 2-plasmin inhibitor in body fluids.

A sensitive method was developed to determine alpha 2 PI at very low concentrations. The minimal measurable concentration of alpha 2 PI was 0.5 ng/assay tube. Using this method, the alpha 2 PI in plasma, urine, amniotic fluid and cerebrospinal fluid was estimated. The mean values and standard deviation for plasma were 5.63 +/- 1.34 mg/dl in 25 males, and 5.29 +/- 1.62 mg/dl in 8 females; in the urine, 0.46 +/- 0.41 microgram/dl in 82 male samples, and 0.69 +/- 0.27 microgram/dl in 8 female samples; in amniotic fluid, 4.13 +/- 2.38 micrograms/dl in 16 samples; and in cerebrospinal fluid, 24.4 +/- 6.6 microgram/dl in 9 samples. The alpha 2 PI level in amniotic fluid was not correlated with the state of the pregnant mother, with that of the baby, or with the protein content or pH of the amniotic fluid.

Amniotic Fluid↗
PubMed1982

Low molecular weight trypsin-plasmin inhibitors isolated from papain treated urinary trypsin inhibitor.

Papain treatment of human urinary trypsin inhibitor (UTI67; mol. wt. 43,000 by SDS-polyacrylamide gel electrophoresis, specific activity 1,897 U/mg protein) produced four new protease inhibitors, which were highly purified by gel chromatography on Sephadex G-100 and isoelectric focusing. The purified inhibitors (UTI26, UTI9-I, UTI9-II, and UTI9-III) were shown to be homogeneous by polyacrylamide disc gel electrophoresis, and had apparent molecular weights of 26,000, 9,000, 9,000, and 9,800, respectively, by sodium dodecyl sulfate gel electrophoresis. During enzymatic degradation of UTI67, the amino acid compositions changed to more basic, and the isoelectric point increased from pH 2.0 (UTI67) to pHs 4.4, 5.2, 6.6, and 8.3 (UTI26, UTI9-I, UTI9-II, UTI9-III), respectively. Both the parent and degraded inhibitors had anti-plasmin activity as well as antitrypsin and anti-chrymotrypsin activities. Much higher anti-plasmin/anti-trypsin and anti-plasmin/anti-chymotryspin activities were observed in the degraded inhibitors than in the parent UTI67. They competitively inhibited human plasmin with Ki values of 1.13 X 10(-7) - 2.12 X 10(-6) M (H-D-Val-Leu-Lys-pNA substrate). The reactions were very fast and the active site of the inhibitors of plasmin was thought to be different from that to trypsin or chymotrypsin.

Amino Acids↗