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Biomedical subjects

M Yamazaki

Publications and source records attributed to M Yamazaki.

At least 631 records · Page 35Linked to original sources
PubMed1990

Precolumn derivatization technique for high-performance liquid chromatographic determination of penicillins with fluorescence detection.

A precolumn derivatization method was developed for the high-performance liquid chromatographic (HPLC) determination of penicillins using fluorescence detection. Penicillins were derivatized by a two-step reaction, the beta-lactam ring being opened by hydrolysis in aqueous sodium carbonate solution in the first step to give a secondary amine functionality, and the secondary amino group being reacted with 7-fluoro-4-nitrobenzo-2-oxa-1,3-diazole in the second step to give a fluorescent derivative. The resulting reaction mixture was injected directly onto a reversed-phase column and analysed by HPLC. At a penicillin concentration of 10 micrograms/ml, the precision (relative standard deviation) ranged from 1.49 to 2.20%. In the concentration range 0.2-100 micrograms/ml, a linear response was observed. The detection limits of this method were 30-85 ng/ml for five different penicillins at a signal-to-noise ratio of 3:1. The proposed method was applied to the determination of penicillins added to serum following pretreatment by deproteinization and removal of compounds containing amino functionalities with a cation-exchange resin.

Chromatography, High Pressure Liquid↗
PubMed1990

Comparative studies on lipid and colony-stimulating factor-induced macrophage growth.

We previously reported that lipids such as cholesterol esters, triglycerides, and some phospholipids that constitute cell membranes or serum lipoproteins induced growth of mouse peritoneal macrophages in vitro. In this paper, we compared the macrophage growth-stimulating activity of cardiolipin (CL), an active phospholipid with that of CSF-1. Growth kinetics and maximal degree of growth of exudated macrophages induced by CL were similar to those of CSF-1. CL did not stimulate macrophages to release soluble macrophage growth factors. Also, the activity of CL was not blocked as much by anti-CSF-1, suggesting that most of the effect of CL was direct and not mediated by CSF-1 or other protein factors. There was no synergistic effect between CL and CSF-1. CL induced growth of both exudate and resident macrophages, whereas CSF-1 induced very little resident macrophage growth. Furthermore, although the growth-stimulating activities of both substances were inhibited by IFN-gamma and TNF, CL was more resistant to these inhibitory effects. These results suggest that the lipid has some different characters from CSF-1 and may induce the growth of resident macrophages in inflammations or tumors.

Animals↗
PubMed1990

Augmentation of macrophage growth-stimulating activity of lipids by their peroxidation.

Previously, we reported that some kinds of lipids (cholesterol esters, triglycerides, and some negatively charged phospholipids) that are constituents of lipoproteins or cell membranes induce growth of peripheral macrophages in vitro. In this paper, we examined the effect of peroxidation of lipids on their macrophage growth-stimulating activity because lipid peroxidation is observed in many pathological states such as inflammation. When phosphatidylserine, one of the phospholipids with growth-stimulating activity, was peroxidized by UV irradiation, its macrophage growth-stimulating activity was augmented in proportion to the extent of its peroxidation. The activity of phosphatidylethanolamine was also increased by UV irradiation. On the other hand, phosphatidylcholine or highly unsaturated free fatty acids, such as arachidonic acid and eicosapentaenoic acid, did not induce macrophage growth irrespective of whether they were peroxidized. The augmented activity of UV-irradiated phosphatidylserine was not affected by the coexistence of an antioxidant, vitamin E or BHT. These results suggest that some phospholipids included in damaged cells or denatured lipoproteins which are scavenged by macrophages in vivo may induce growth of peripheral macrophages more effectively when they are peroxidized by local pathological processes.

Animals↗
PubMed1990

Deformation and instability in membrane structure of phospholipid vesicles caused by osmophobic association: mechanical stress model for the mechanism of poly(ethylene glycol)-induced membrane fusion.

The mechanism of poly(ethylene glycol)-induced fusion of phospholipid vesicles was studied based on the "osmophobic association" theory which was recently proposed both theoretically [Ito, T., Yamazaki, M., & Ohnishi, S. (1989) Biochemistry 28, 5626-5630] and also experimentally [Yamazaki, M., Ohnishi, S., & Ito, T. (1989) Biochemistry 28, 3710-3715]. Osmophobic association and fusion were detected by measuring the light scattering of the vesicle suspension; the former was detected from the increase in light scattering induced by the addition of PEG, and the latter was from the irreversibility of the increase in light scattering. Threshold concentrations of PEG were required not only for osmophobic association but also for fusion. The threshold concentration for fusion depended on the molecular weight of PEG and also on the electrostatic repulsive interaction between phospholipid vesicles, which was manipulated by the use of vesicles with negative surface charge; increasing the molecular weight of PEG lowered the threshold concentration, and increasing the electrostatic repulsive interaction raised it. In addition, a transient leakage of internal contents from the vesicles was observed at the concentration that caused fusion. When the surface charge of the vesicle was varied, the threshold for fusion coincided with that for osmophobic association, provided that the latter exceeded 22 wt % of PEG 6000. However, when the threshold for osmophobic association was less than 22 wt %, the threshold for fusion remained approximately 22 wt %, irrespective of the difference in the threshold for osmophobic association.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Stimulation of a histone H4 protein kinase in Triton X-100 lysates of rabbit peritoneal neutrophils pretreated with chemotactic factors: lack of requirements of calcium mobilization and protein kinase C activation.

The characteristics of the activation of a histone H4 kinase activity in Triton X-100 lysates of rabbit peritoneal neutrophils pretreated with fMet-Leu-Phe were studied: The activation of the kinase was a) inhibited by the antagonist of formylpeptide, t-Boc-(Phe-Leu)2(-)-Phe, b) completely inhibited by pertussis toxin pretreatment, c) not affected by the pretreatment of neutrophils with an activator of protein kinase C, phorbol-12-myristate-13-acetate, or an inhibitor of protein kinase C, 1-(5-isoquinoline-sulfonyl)-2-methyl-piperazine, and d) not inhibited in the cells preloaded with the intracellular calcium chelators, bis-(o-aminophenoxy)-ethane-N,N,N',N'-tetra acetic acid acetoxymethyl-ester (BAPTA/AM). These results suggest that the stimulus-induced activation of H4 kinase requires functional receptor and GTP-binding protein but neither calcium mobilization nor protein kinase C activation.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1990

Some properties of the apoenzyme of NADPH-adreno-ferredoxin reductase from bovine adrenocortical mitochondria.

1. An apo-NADPH-adreno-ferredoxin reductase (EC 1.18.1.2) was obtained from bovine adrenocortical mitochondria and its physicochemical properties were investigated. 2. The effects of various substances such as NADPH, FAD and adreno-ferredoxin on the interaction of the apo-reductase were investigated by various column chromatographies. 3. The apo- and holo-reductases were found to be separated by adreno-ferredoxin affinity chromatography. 4. The removal of FAD from NADPH-adreno-ferredoxin reductase did not affect the net charge of the reductase. 5. The values of s20,w of apo- and holo-reductases were 3.8 x 10(-13) sec and 3.9 x 10(-13) sec, respectively. 6. The apo-reductase was more easily denatured by heat treatment than the holo-reductase. 7. FAD, and adreno-ferredoxin and both could protect the apo-reductase from thermal inactivation.

Adrenal Cortex↗
PubMed1990

Purification and some properties of a hemolysin from the poisonous mushroom Rhodophyllus rhodopolius.

A hemolytic protein which causes diarrhea and death to mice was purified from the fruit bodies of a poisonous mushroom species Rhodophyllus rhodopolius (Fries) by DEAE-cellulose column chromatography, ammonium sulfate precipitation, gel filtration on Sephadex G-200, and DEAE-Sephadex A-25 column chromatography. The mol. wt of the purified hemolysin was estimated to be 40,000 by SDS-polyacrylamide slab gel electrophoresis. The hemolytic activity of the purified hemolysin was destroyed by heating at 60 degrees C for 10 min, and partially reduced by pepsin, papain and 2-mercaptoethanol. Cholesterol and phosphatidylcholine did not inhibit the activity. The hemolysin was unstable below pH 7.0 but stable at pH 8.0. The optimal pH for hemolysis was 6.0. Hemolysis did not occur below 4 degrees C even though the hemolysin bound to the erythrocyte. Mouse, chicken, rat, horse and human erythrocytes were sensitive in this order, but sheep and cow erythrocytes were not lysed by the toxin.

Animals↗
PubMed1990

Bacteriostatic and cytolytic activity of purple fluid from the sea hare.

A bacteriostatic factor, aplysianin P, was purified from the purple fluid of a sea hare, Aplysia kurodai, as a glycoprotein of 60 K daltons. A cytolytic glycoprotein purified from the purple fluid of Dolabella auricularia did not show antibacterial activity. Aplysianin P was half-maximally active for gram-positive and -negative bacteria at 0.2-5.8 micrograms/mL and its action was not bactericidal but bacteriostatic. Aplysianin P completely inhibited the syntheses of DNA and RNA by E. coli, but it did not induce the release of ATP from bacteria. These results suggest that aplysianin P, found in an invertebrate, the sea hare, is a new bacteriostatic protein and that it exerts its action by inhibiting nucleic acid syntheses, as a DNA-inhibiting, chemotherapeutic drug does.

Animals↗
PubMed1990

Crystallization and comparative characterization of reduced nicotinamide adenine dinucleotide phosphate-ferredoxin reductase from sheep adrenocortical mitochondria.

1. Sheep NADPH-ferredoxin reductase (E.C. 1.18.1.2) was purified from the adrenocortical mitochondria. The reductase was typical flavoenzyme and crystallized in ammonium sulfate solution. 2. The properties of the reductase were investigated physicochemically and immunochemically. The minimum molecular weight of the reductase was 52,000 and the reductase has one FAD per mole as a coenzyme. 3. The sheep NADPH-ferredoxin reductase showed a precipitate line against antibody to bovine NADPH-ferredoxin reductase. 4. The compositions and sequences of amino acid residues of this reductase and porcine, bovine, and human enzymes were compared. In spite of differences of mammalian species, the sequence of amino acid residues in the amino-terminal regions were highly homologous. 5. It is suggested that the amino-terminal region may be essential for the function of the NADPH-ferredoxin reductase.

Adrenal Cortex↗
PubMed1990

Determination of cardiac glycosides in digitoxin tablets and deslanoside injections by micro-HPLC.

A micro high-performance liquid chromatographic (micro-HPLC) procedure for the assay of digitoxin tablets and deslanoside injections has been developed. Micro-HPLC is performed on an ODS micro column, with acetonitrile-methanol-water (10:20:17) for digitoxin tablets and acetonitrile-water (21:70) for deslanoside injections. The effluent is monitored by UV absorption at 220 nm. Quantitation of cardiac glycosides in tablets and injections is carried out by the internal standard method. The composite assay results for digitoxin tablets and deslanoside injections provide average values of 101.2 and 99.9% with standard deviations of 1.2 and 0.93%, respectively. This micro-HPLC method is sensitive, quantitative, and reproducible. It is suitable for use in examining the content uniformity of pharmaceutical preparations.

Chromatography, High Pressure Liquid↗
PubMed1990

The effect of fatty acids on the rectal absorption of acyclovir in rats.

The enhancing effect of fatty acids on the rectal absorption of acyclovir has been evaluated in rats. Acyclovir proved to be absorbed to the extent of 3 to 9% after oral administration. After rectal administration in the absence of absorption-promoter, the bioavailability of acyclovir was 37%. Its rectal administration with 4% sodium caprate resulted in enhanced bioavailability (81 +/- 3%).

Acyclovir↗
PubMed1990

Purification and characterization of alkaline phosphatase of Bacteroides gingivalis 381.

Cell-associated alkaline phosphatase (ALPase) of Bacteroides gingivalis 381 was found in the outer part of the periplasmic space by using an ultracytochemical procedure. Cell-associated ALPase was solubilized by extraction with 1% Triton X-100, and the solubilized enzyme was purified 904-fold with 5.6% recovery by using affinity column chromatography for mammalian intestinal-form ALPase. The purified enzyme gave a single protein band that corresponded to the enzyme activity band on polyacrylamide gel electrophoresis preparations. A single protein band at a molecular weight of 61,000 was observed on sodium dodecyl sulfate-polyacrylamide gel electrophoresis preparations. The molecular weight of the native enzyme was estimated to be 130,000 by gel filtration with TSK-gel G3000SW. These findings indicate that B. gingivalis ALPase is a homodimer. The optimal pH of the enzyme was between 9.1 and 9.3 in the absence of divalent metal ions and was between 10.1 and 10.3 in the presence of manganese or zinc ions. The apparent km for p-nitrophenylphosphate was 0.037 +/- 0.003 mM (mean +/- standard deviation) at pH 9.2 in the absence of divalent metal ions and 0.22 +/- 0.02 mM at pH 10.2 in the presence of 1 mM manganese ions. Under both of the conditions described above, the purified enzyme was able to hydrolyze casein and O-phosphoserine, suggesting that B. gingivalis ALPase can act as a phosphoprotein phosphatase. ALPase that immunologically cross-reacted with the purified enzyme was found in the extracellular soluble fraction. This means that ALPase is released from the periplasmic space into the culture supernatant as a soluble form.

Alkaline Phosphatase↗
PubMed1990

Binding of 2-amino-4-chloro-m-benzenedisulfonamide as a metabolite of hydrochlorothiazide to erythrocytes.

2-Amino-4-chloro-m-benzenedisulfonamide (ACBS) is a metabolite of hydrochlorothiazide. We reported that the ACBS concentration in erythrocytes was higher than in plasma in a patient. Therefore the binding of ACBS to rabbit erythrocyte was studied. The Scatchard plot showed the nonlinear plot and the horizontal asymptote. Curvature in this plot indicated the existence of 2 classes of binding. One class was at a specific site, probably at carbonic anhydrase. Chromatographic data seemed to support the possibility.

Animals↗
PubMed1990

Structures of novel epipolythiodioxopiperazines, emethallicins B, C, and D, potent inhibitors of histamine release, from Emericella heterothallica.

Novel compounds designated emethallicins B (1), C (2), and D (3), along with emethallicin A (4), were isolated from the mycelium of the heterothallic fungus, Emericella heterothallica (mating type a). The structures of emethallicins B (1), C (2), and D (3) were determined on the basis of spectroscopic and chemical investigations. Emethallicins B (1) and C (2) are epitetrathiodioxopiperazines, which have the same basic carbon skeleton as apoaranotin (19) and acetylaranotin (17), respectively, whereas emethallicin D (3) is an epitrithiodioxopiperazine derivative, which has the same carbon skeleton as apoaranotin (19). It is very interesting that a large amount of the disulfide, emethallicin A (4), was isolated from the strain of mating type A and that the corresponding tetrasulfide, emethallicin B (1), and trisulfide, emethallicin D (3), were isolated from the other mating type strain, along with a small amount of the disulfide (4). Emethallicins B (1), C (2), and D (3) have potent inhibitory activity against compound 48/80-induced histamine release from mast cells, like emethallicin A (4).

Aspergillus↗
PubMed1990

[Studies on pharmacologically active principles from Indonesian crude drugs. III. Toxic components from Brucea javanica (L.) Merr].

During our screening of pharmacologically active principles from Indonesian medicinal plants by a hypothermic effect the methanol-extract of Brucea javanica (L.) Merr. has been found to exhibit a lethal toxicity to mice. The toxic components were isolated and identified with bruceoside A and B and yadanzioside F. Correction of 13C-nuclear magnetic resonance assignment was also mentioned.

Animals↗
PubMed1990

Glomerular filtration response to acute loading with protein from different sources in healthy volunteers and diabetic patients.

To evaluate the effects of acute protein loading on the glomerular filtration rate, albumin excretion rate and concentration of plasma amino acids, ten healthy volunteers and six type 2 diabetic patients with normoalbuminuria were studied before and after eating 0.7 g/kg body weight of tuna fish, boiled egg white, cheese or tofu (bean curd) on separate days. Furthermore, to study the possible role of glucagon, growth hormone, atrial natriuretic peptide and kallikrein in the responses of glomerular filtration rate to protein, these substances were measured before and after ingestion of tuna fish or egg white in six healthy volunteers. In healthy subjects, glomerular filtration rate increased significantly (p less than 0.01) from 98.1 +/- 4.2 ml/min during the baseline period to 129.9 +/- 6.6 ml/min after ingestion of tuna fish. No significant differences were seen between glomerular filtration rate before and after ingestion of egg white, cheese or bean curd. No significant differences were observed between the baseline albumin excretion rate and that after loading with any of the four kinds of protein. Plasma concentrations of alanine, glycine and arginine (amino acids known to induce glomerular hyperfiltration) increased to a greater degree after ingestion of tuna fish than after administration of the other meals. Diabetic subjects and healthy volunteers had similar responses. Plasma glucagon and growth hormone concentrations increased after ingestion of the tuna fish meal or egg white. Plasma atrial natriuretic peptide concentration and urinary kallikrein excretion were unaffected by ingestion of these two kinds of protein. These findings suggest that responses of glomerular filtration rate to acute protein loading may differ depending on the protein ingested, and that these responses may not be directly induced by glucagon, growth hormone, atrial natriuretic peptide or kallikrein.

Adult↗
PubMed1990

Dye penetration of the smear layer and fluoride application to the dentin surface.

A smear layer is formed after cavity or root canal preparation. The aim of the present study was to reinforce the dental surface in order to prevent the invasion of foreign irritants, by treating the smear layer with fluoride. Dentinal samples whose surfaces had been washed with water after the formation of a smear layer, and corresponding samples without washing, were examined by the dye penetration test, and the results were compared. Although there was no significant difference between the two groups of samples, dye penetration was suppressed by about 30% in washed samples, whereas the suppression was 20% in unwashed samples. When washed samples were treated with 1.0% SnF2, 10.0% SnF2, 7.5% Na2PO2F, 15% Na2PO2F, APF, 10 mM In(NO3)3, 100 mM TiF3, 50 mM TiF3, or 10 mM TiF3, samples washed after treatment with 1.0% SnF2 showed a dye penetration suppression of about 60% as a whole, in comparison with samples having no smear layer. Hardly any suppression of dye penetration was observed after treatment with other fluorides.

Acid Etching, Dental↗