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Biomedical subjects

H Fujisaki

Publications and source records attributed to H Fujisaki.

At least 73 records · Page 4Linked to original sources
PubMed1984

Localization of the active site and phosphorylation site of Acanthamoeba myosins IA and IB.

The 130- and 125-kDa heavy chains of Acanthamoeba myosins IA and IB were radioactively labeled at either the regulatory phosphorylation site or the catalytic site and then subjected to controlled proteolysis by either trypsin or chymotrypsin. The labeled and unlabeled peptides generated during the course of proteolysis were identified by autoradiography and Coomassie Blue staining after separation by electrophoresis on sodium dodecyl sulfate-polyacrylamide gels. The relative positions of the phosphorylation and active sites could be deduced. The catalytic site of myosin IA is most probably within 38 kDa of one end of the 130-kDa heavy chain, and the phosphorylation site, which can be no more than 40 kDa away from the catalytic site, would then be between 38 and 78 kDa of that same end of the heavy chain. Possibly, the phosphorylation site is further restricted to the region between 38 and 64 kDa from the end of the heavy chain. The catalytic and phosphorylation sites of myosin IB are both contained within a segment of 62 kDa at one end of the 125-kDa heavy chain and are within 40 kDa of each other. The phosphorylation site may be restricted to a small segment between 60 and 62 kDa from one end of the heavy chain which would limit the possible position of the catalytic site to the region between 20 and 60 kDa of that end.

Amoeba↗
PubMed1984

[Immuno-cytochemical and -histochemical localization of human keratin proteins in various kinds of cancerous lesion].

Immunoperoxidase staining for human keratin proteins (hKP) was performed cytochemically in samples from 79 cancer patients, and histochemically in samples from 134 cancer patients. Immunohistochemically, hKP was present in almost all patients with squamous cell carcinoma (lung), transitional cell carcinoma (urinary bladder), adenocarcinoma (lung, stomach, breast, ovary), bronchiole-alveolar carcinoma (lung), and large cell carcinoma (lung). It was detected in 40% of the patients with small cell carcinoma (lung). Histochemically, hKP was present in patients with squamous cell carcinoma (lung, uterine body), adenocarcinoma (lung, stomach, colon, gall bladder, thyroid, uterine body), adenosquamous cell carcinoma (gall bladder, uterine body), Signet-ring cell carcinoma (stomach), clear cell carcinoma (uterine body) and undifferentiated carcinoma (uterine body). However, it was not detected in patients with brochiole ++-alveola ++ carcinoma (lung) and mucinous carcinoma (gall bladder).

Breast Neoplasms↗
PubMed1983

Effect of synthetic acyclic polyisoprenoids on the cold-restraint stress induced gastric ulcer in rats.

The antiulcer effect of a series of synthetic acyclic polyisoprenoids on cold-restraint stress induced ulcer in female rats was determined, and the relationship between their antiulcer effect and chemical structure was also investigated. As a result, the following findings were obtained: The antiulcer effect of acyclic polyisoprenoids closely correlated with the number of intramolecular isoprene units, and geranylgeranyl derivatives showed a particularly marked antiulcer effect. The terminal polar groups such as 2-oxopropyl and 2-hydroxypropyl groups in geranylgeranylacetone seemed to play an important role in the antiulcer activity of acyclic polyisoprenoids. Terminal bulky groups decreased their antiulcer activity, however. The antiulcer activity of geranylgeranylacetone correlated with the number of intramolecular double bonds. There was no significant difference in antiulcer activity between all-trans-geranylgeranylacetone, 5-cis-geranylgeranylacetone and the mixture of these isomers (1:1 and 3:2). The results of this experiment suggested that the antiulcer activity of acyclic polyisoprenoids might be governed by such factors as the number of isoprene units, terminal polar groups, and number of intramolecular double bonds.

Animals↗
PubMed1983

Effect of geranylgeranylacetone on aspirin-induced changes in gastric glycoproteins.

The effects of aspirin and treatment with geranylgeranylacetone (GGA), an antiulcer drug, on the content of gastric glycoproteins were investigated in pylorus-ligated rats. In normal rats, the amount of gastric glycoproteins in the mucous layer was about 1.5 times higher than that in the gastric mucosa, indicating that the glycoproteins were distributed in the mucous layer as a highly concentrated state. Aspirin (100 mg/kg, p.o.) decreased the content of gastric glycoproteins both in the mucous layer and in the gastric mucosa. The amount of the macromolecular fraction in the gastric juice, which corresponded to the gastric glycoproteins on the basis of molecular size, was not affected by aspirin. GGA (300 mg/kg, i.d.) could prevent the decreases of the total amount of gastric glycoproteins in the mucous layer plus gastric mucosa. These results indicated that the glycoproteins coating the surface of the gastric mucosa may play a role as a defensive mechanism and that GGA exerted an antiulcer effect on aspirin-induced mucosal damage through preventing the decreases in gastric glycoproteins.

Animals↗
PubMed1983

[Genetic and physiological studies of mouse systolic blood pressure].

At the present, it is obviously demonstrated that the blood pressure is genetically controlled. But genetical analysis are not well done because it is very complicated in relation to the environmental factors. In this study, the systolic blood pressure measurement and some blood examinations were carried in 23 inbred strain mice which were relatively representative in different genetical background groups and included 2 diabetic mutants, 1 obese mutant and 1 obese congenic mouse, and the relations were calculated between them. And also the heritability and the number of genetic loci of blood pressure were determined with the hybridization experiment. The results obtained were as follows. About 50 mmHg difference was shown among the blood pressure of different inbred mice. The strains of 129/J, JPW , XP and C57BL/6J indicated lower values, and NZB, ICR, C3H and PL/J strain showed higher blood pressure. Diabetic mutants demonstrated relatively higher values compared with control mice. It was demonstrated that the blood pressure rose high correlatively with the age in the experiment of prediabetic NOD mouse. Remarkable correlations were shown between the blood pressure and serum triglyceride and cholesterol especially in diabetic mice. It was calculated that the blood pressure was controlled by about 5 genetic loci and the heritability was 0.3455.

Age Factors↗
PubMed1982

Heterogeneity in enzymatic sites of heavy meromyosin shown by measuring F-actin-inactivated hydrolysis of beta-naphthyl triphosphate.

Enzymatic characteristics of heavy meromyosin (HMM) were investigated by measuring beta-naphthyl triphosphate (beta-NapP3) hydrolysis in the presence and absence of F-actin. beta-NapP3 hydrolysis by HMM was inactivated by F-actin in the presence of Mg ions; in the presence of sufficient F-actin, the activity was about one-half of that in the absence of F-actin. In the presence of Ca ions the activity disappeared almost completely on addition of sufficient F-actin. Two different values of the Michaelis constant (Km) were obtained from the data for beta-NapP3 hydrolysis by HMM in the presence of Mg ions; one of them vanished in the presence of sufficient F-actin, and only one Km value was obtained in the presence of Ca ions. These results suggest the existence of two distinct enzymatic sites in HMM, one inactivated by F-actin in the presence of Mg or Ca ions, the other inactive in the presence of Ca ions but active in the presence of Mg ions and not influenced by F-actin. Use of subfragment-1(A1) (S-1(A1)) and S-1(A2) instead of HMM confirmed that these enzymatic characteristics are not due to a difference in the alkali light chains on myosin heads.

Actins↗
PubMed1982

Effects of the antiulcer drug geranylgeranylacetone on aspirin-induced gastric ulcers in rats.

Antiulcer effects of geranylgeranylacetone (GGA) on aspirin-induced gastric ulcers in rats were studied, comparing them with those of gefarnate. The oral administration of GGA prevented the development of gastric ulcer induced by a single or repeated oral administration (5 consecutive days) of aspirin. The effects of GGA were more potent and more definite than those of gefarnate. The intraduodenal administration of GGA, but not the intragastric administration, also inhibited the ulceration induced by aspirin in pylorus-ligated rats, while the intraduodenal administration of gefarnate did not. GGA prevented the reduction of the H+ concentration and the increment of Na+ concentration in the gastric juice induced by aspirin. In addition, the decrease of hexosamine content in the gastric mucosa induced by aspirin was restored to a normal level by GGA, but not by gefarnate. From these results, it was concluded that the protective actions of GGA on aspirin-induced gastric ulcers might be due to its protection from the weakening of gastric mucosal resistances.

Animals↗
PubMed1981

Inhibition of palmitoyl CoA of EDTA- and Mg2+-ATPase of heavy meromyosin from rabbit skeletal muscle.

Palmitoyl CoA inhibited EDTA-ATPase of heavy meromyosin (HMM) prepared from rabbit skeletal muscle. The concentration for half maximum inhibition of EDTA-ATPase was about 18 microM. Myristoyl CoA, the other long chain fatty acyl CoA, also inhibited EDTA-HMM ATPase, but CoA and short chain CoA thioesters, such as butyryl CoA, acetoacetyl CoA and acetyl CoA, at 40 microM hardly inhibited EDTA-ATPase. Less than 20% inhibition of EDTA-HMM ATPase was obtained with Na-palmitate and Na-myristate at 40 microM, whereas about 90% inhibition of the enzyme occurred in the presence of 40 microM palmitoyl CoA and myristoyl CoA. Palmitoyl carnitine, as well as carnitine, failed to inhibit EDTA-HMM-ATPase. The inhibition of palmitoyl CoA of EDTA-ATPase was reversed by bovine serum albumin and spermine. Mg2+-HMM ATPase activity was enhanced by palmitoyl CoA at 2, 5, and 10 microM. About a 25% increase in Mg2+-HMM ATPase activity was obtained at 5 and 10 microM. At higher concentrations than 20 microM, the enzyme was inhibited by palmitoyl CoA and the degree of inhibition was related to the concentration of the CoA thioester. At 80 microM, the activity was about 15% of the maximum value. The efficacy of myristoyl CoA on Mg2+-ATPase was almost the same as that of palmitoyl CoA. Mg2+-ATPase activity was not enhanced by CoA, butyryl CoA, acetoacetyl CoA, Na-myristate, Na-palmitate, palmitoyl carnitine, or carnitine at 10 microM, and was hardly reduced by these substances at 40 microM. Serum albumin and spermine also canceled, to some extent, these effects of palmitoyl CoA on Mg2+-ATPase.

Acyl Coenzyme A↗
PubMed1981

Antiulcer effect of geranylgeranylacetone, a new acyclic polyisoprenoid on experimentally induced gastric and duodenal ulcers in rats.

Antinuclear effects of geranylgeranylacetone (GGA), new acyclic polyisoprenoid, on several types of experimental gastric and duodenal ulcers were studied in rats. The prophylactic administration of GGA (50--200 mg/kg p.o. or 12.5--50 mg/kg i.p.) reduced the gastric ulcers induced by the exposure to cold-restraint stress and by the administration of indomethacin, acetylsalicylic acid (ASA), prednisolone or reserpine and the duodenal ulcer after the administration of cysteamine, although it was not effective against Shay's ulcer. The curative treatment with GGA accelerated the healing process of the gastric ulcers induced by the topical application of acetic acid or thermocautery and by the administration of ASA with the exposure to cold-restraint stress. The antinuclear effect of GGA was more distinct than that of gefarnate in all types of experimental models studied. Carbenoxolone effectively reduced the gastric ulcer formation by cold-restraint stress when it was administered i.p. but not p.o., whereas GGA was effective either i.p. or p.o. GGA and gefarnate did not affect the gastric secretion in pylorus-ligated rats, whereas carbenoxolone definitely reduced the secretion of gastric juice and acid. Hexosamine content in the stomach was reduced by the exposure to cold-restraint stress. The pretreatment with GGA prevented the reduction in hexosamine contents in the superepithelial mucous layer and mucosal layer. These results may suggest a high possibility that GGA is useful for clinical treatment of peptic ulcers, probably through a mechanism of increasing defence force of the gastric mucosa.

Animals↗
PubMed1981

[Quantitative cineangiographic evaluation of the valvular regurgitant flow ratio by digital image processing technique (author's transl)].

By application of digital image processing technique to cineangiogram, possibility to calculate the valvular regurgitant flow ratio, especially in patents with aortic regurgitation, was examined. The image processor used was RT6404 made by Amast Computer CO, and the microcomputer to control the image processor was H68TR made by Hitachi Industrial Co. The image of the cineangiogram was photographed by televicamera, and the image processor converted the televi-signal to digitized image. Total volume and concentration of contrast medium in the ventricle was integrated in each systole and diastole. In patients without aortic regurgitation, the volume of contrast medium was not increased in the next diastole after the end of injection. On the contrary, in cases of aortic regurgitation, the volume of contrast medium was increased in the next diastole because of regurgitation. Thus, the regurgitant flow ratio could be calculated from the ejected volume in systole immediately before this diastole and the increased volume caused by the regurgitation.

Aortic Valve Insufficiency↗
PubMed1980

Fluorometric method for estimating the kinetic parameters of beta-naphthyl triphosphate and ATP hydrolysis by acto-heavy meromyosin.

We have established a method to estimate the values of various kinetic parameters of acto-heavy meromyosin (acto-HMM) ATPase, using a fluorescent ATP analog, beta-naphthyl triphosphate (beta-NapP3); from the fluorescence intensity change accompanying beta-NapP3 hydrolysis, the various kinetic parameters of beta-NapP3 hydrolysis, including its product inhibition, were obtained. beta-NapPd3 hydrolysis is inhibited competitively by ATP, resulting in different time courses of fluorescence intensity change in the presence and absence of ATP. From this difference, the values of kinetic parameters of ATP hydrolysis, including its product inhibition, can be estimated. By extending this method to the acto-HMM system, seventeen parameters in a reaction scheme for the concurrent hydrolysis of ATP and beta-NapP3, including association constants between F-actin and substrate-free or substrate-bound HMM, were obtained. The kinetic-parameters estimated for ATP hjydrolsis were in good agreement with those in the literature.

Adenosine Triphosphatases↗
PubMed1980

Electric potential at regions near the two specific thiols of heavy meromyosin determined by the fluorescence quenching technique. I. Effect of ATP.

Electric potentials at regions near the two specific thiol groups, SH1 and SH2, of the heavy meromyosin (HMM) molecule were studied by the fluorescence quenching technique. The effects of binding of ATP to HMM upon the electric potentials were also studied. N-(p(2-Benzimidazolyl)phenyl)maleimide (BIPM) was used as a thiol-directed fluorescent reagent. Prior to the labeling of SH2 with BIPM, the SH1 group was blocked with N-ethylmaleimide (NEM). Iodide ions (I-), thallium ions (Tl+), and acrylamide were used as quenchers of fluorescence. The sign of the electric potential was collectively determined from the dependence of the Stern-Volmer constants upon the ionic strength of solutions. 1. The region near SH1 was at a negative electric potential, whereas the electric potential at the region near SH2 was almost zero. 2. On the addition of ATP, the fluorescence intensity of BIPM bound to SH1 was unchanged, whereas that of BIPM bound to SH2 was greatly decreased to about 50% of the original level. The fluorescence intensity recovered as the added ATP was split into ADP and orthophosphate, and became saturated. The saturated level of the fluorescence intensity was, however, smaller than the original one, due to binding of the produced ADP to HMM. 3. On the addition of ATP, the negative electric potential at the region near SH1 was unchanged, whereas a negative electric potential with large gradient was newly introduced at the region near SH2. The value of the newly introduced electric potential was calculated on the basis of various assumptions. These results are discussed in connection with the functions of myosin.

Acrylamides↗
PubMed1978

Some characteristics of beta-naphthyl triphosphate as a substrate of heavy meromyosin. F-actin-inactivated hydrolysis showing initial burst.

The initial burst of Pi liberation was found in the hydrolysis of beta-naphthyl triphosphate (beta-NapP3) by heavy meromyosin (HMM) in the presence of Mg ions as well as in the hydrolysis of ATP. However, unlike that of ATP, the steady-state hydrolysis of beta-NapP3 by HMM was inhibited by the addition of F-actin to the reaction solution. Although the possession of an initial burst-like property during interaction of a substrate and myosin is believed by many investigators to be a key factor in F-actin activation of substrate hydrolysis in vitro and in the molecular mechanism of muscle contraction, the above results suggest that this is not generally true. beta-NaP3 did not induce superprecipitation of actomyosin solution and suppressed ATP-induced superprecipitation.

Actins↗