Biomedical subjects

M Tsuchiya

Publications and source records attributed to M Tsuchiya.

At least 307 records · Page 17Linked to original sources

PubMed1990

Thrombopoietic activity of human interleukin-6.

Thrombopoietin (TPO), a regulatory factor in platelet production, was purified from the conditioned medium of TNK-01 cells cultured in the presence of human interleukin-1. The N-terminal sequence of purified TPO was determined to be VPPGEDSKDVAAPHRQPLT, identical to that of the N-terminal region of human interleukin-6 (IL-6). Two forms of TPO with molecular masses of 24 and 27 kDa were identified as IL-6 by Western analysis using an anti-IL-6 antibody. Commercial recombinant human IL-6 produced in Escherichia coli, stimulated megakaryocyte colony formation in the presence of mouse interleukin-3 and increased the number of peripheral platelets in mice in a dose-dependent manner. From these results, it is concluded that human IL-6 has thrombopoietic activity.

Amino Acid Sequence↗

PubMed1990

Alkaline phosphatase of rat intestinal lymph: its characterization and the effect of fat administration.

Biological characteristics of alkaline phosphatase (ALP) from rat intestine were compared among four various fractions (brush border, cytosol, luminal and lymph) to clarify the source and route of ALP appeared in intestinal lymphatics. ALP of each fraction had the same Km values and the same heat stability and all were of intestinal type. However, lymph and cytosol ALP showed similar affinity to three kinds of lectins and were distinct from membrane and luminal ALP. On polyacrylamide gel electrophoresis (PAGE), there seems to be two types of charge isomers of intestinal ALP, namely brush border type and lymph type. On sodium dodecyl sulfate (SDS)-PAGE, the molecular weight of principal band for each form was: 130,000 for brush border type, and 160,000 for lymph type. Fat administration significantly increased the ALP activity in intestinal lumen and intestinal lymph. However, it did not change biological characteristics of ALP including binding ability to lectins and electrophoretic mobility in any of these four fractions. These results suggest that lymphatic ALP may be transported from cytosol of intestinal cells and that fat administration seems to induce quantitative change of intestinal ALP, but not to change its physiological route of transportation into intestinal lymph.

Alkaline Phosphatase↗

PubMed1990

Histochemical and immunohistochemical evidence for hepatic zone 3 distribution of alcohol dehydrogenase in rats.

The distribution of alcohol dehydrogenase in the hepatic acinus was examined by both histochemical and immunohistochemical approaches. The immunohistochemical method using anti-alcohol dehydrogenase antibody indicated zone 3 predominance of this enzyme in the hepatic acinus, whereas a conventional histochemical method showed slight zone 1 predominance. However, when the histochemical technique was improved by using 2% glutaraldehyde instead of formalin for fixation and by adding phenazine methosulfate (0.33 mmol/L) to the staining incubation mixture, this method also supported zone 3 predominance of alcohol dehydrogenase. Evidence for zone 3 distribution of alcohol dehydrogenase may be of value in elucidating the mechanism of zone 3 liver damage by alcohol.

Alcohol Dehydrogenase↗

PubMed1990

Teratogenicity of arotinoids (retinoids) in vivo and in vitro.

The effect of structural modifications on the arotinoid molecule, a new class of retinoids, on their teratogenicity in mice was studied. Animals were treated on days 8 and 9 of gestation, the most susceptible stages to retinoid-induced malformations in rodents. The teratogenic potency of the 13 arotinoids tested varied over a dose range of more than five orders of magnitude. Next, we tested whether the quantitative differences in the teratogenicity of these arotinoids correlates with their activity in high density (micromass) cultures of rat embryonic limb bud and midbrain cells. There was a good quantitative correlation between the in vivo teratogenicity and the in vitro activity in limb bud cells but no correlation was found in midbrain cells. Thus, the limb bud cell culture system may be useful for a preliminary testing to select non-teratogenic retinoids. For the risk assessment in humans, however, the in vitro results should be verified in animals studies.

Abnormalities, Drug-Induced↗

PubMed1990

Importance of retinal pigmentation as a subclinical marker in familial adenomatous polyposis.

Surgery was performed in 35 patients with familial adenomatous polyposis (FAP) from 22 family trees. To clarify retinal pigmentation as an important subclinical marker in patients with FAP, precise retinal examinations were performed in 41 cases (82 eyes), including 23 patients and 18 family members including 12 second-generation and third-generation possible carriers. In 27 patients, precise studies were done on accompanying lesions, and the number of polyps was counted at the time of surgery in each patient in every family tree. The overall incidence of retinal pigmentation in patients was 82.6 percent. The incidence of retinal pigmentation in possible carriers was found to be 50 percent, which is comparable with the calculated expressibility of the polyps. The shape and distribution of pigmentations were classified into two categories--large and small. A total of 1984 control retinal examinations were performed, which revealed only six retinal pigmentations (0.3 percent). In the control group, all pigmentation was solitary and unilateral. No large pigmentations in bilateral eyes were found in the control group. In large pigmentation, the sensitivity and specificity were calculated as 0.652 and 0.999, respectively, and in small pigmentation, the sensitivity and specificity were calculated as 0.783 and 0.997, respectively. Small pigmentation appears to increase in number around the age of the appearance of the polyp. Earliest recognition of the pigmentation in this series was one year of age.

Adenomatous Polyposis Coli↗

PubMed1990

A new method for the quantification of beta-glucan in plasma and its application in the diagnosis of postoperative infection.

In order to correctly diagnose and treat severe postoperative infections, it may be critical to detect and differentiate between endotoxin derived from Gram-negative bacteria and/or beta-glucan derived from fungi. In addition to the chromogenic assay, the turbidimetric kinetic assay has been performed for the quantification of endotoxin in plasma using Limulus amebocyte lysate as previously reported. However, it is also known that beta-glucan triggers the coagulation of Limulus amebocyte lysate. In the present study, the differentiation of beta-glucan from endotoxin and its clinical application were studied. Endotoxin was able to be inactivated in plasma using one-tenth dilution by 10 per cent ethanol or distilled water, followed by heating at 100 degrees C for 120 min, without affecting the activity of coexisting beta-glucan. The treated sample was then subjected to the turbidimetric kinetic assay using Toxinometer ET-201. Using this method, as little as 30 pg/ml of beta-glucan in the plasma may be assayed separately, with the amount of circulating beta-glucan in the plasma of normal subjects being less than 50 pg/ml. On the other hand, in patients with a fungal infection, the amount of beta-glucan in their plasma was elevated significantly. Clinically, beta-glucanemia may often occur in severe postoperative infection even if fungi are not detected.

Candidiasis↗

PubMed1990

Response of Müller cells following experimental lensectomy-vitrectomy.

We used morphological, biochemical and immunohistochemical methods to assess the response of Müller cells after experimental lensectomy-vitrectomy in rabbits. We observed widened intercellular spaces between the Müller cells and nerve fibers of ganglion cells, and increased electron opacity in the Müller cells of eyes injected with silicone oil. No apparent morphological changes were detected in the Müller cells of air-injected eyes. The specific and total activities of Müller cell-marker enzymes (glucose 6-phosphatase and glutamine synthetase) showed an initial increase, followed by a decrease. Glial fibrillary acidic protein immunoreactivity was not found in the Müller cells of the normal rabbit retina but was exhibited after surgery. Our results showed that markers of Müller cells associated with glycogenolysis and/or gluconeogenesis, glutamate-glutamine cycle and cytoskeletal protein metabolism were affected by the experimental lensectomy-vitrectomy.

Air↗

PubMed1990

Halothane enhances the phosphorylation of H1 histone and rat brain cytoplasmic proteins by protein kinase C.

The effect of halothane, a typical volatile anesthetic, on the calcium- and phospholipid-dependent protein kinase (PKC), which is one of the key enzymes of membrane signal transduction, was examined. PKC was partially purified from the cerebral tissue of male Wistar rats. Halothane increased PKC-mediated phosphorylation of calf thymus H1 histone in the presence or absence of phorbol ester or diolein, and also increased phosphorylation of the rat brain cytosolic proteins (47 kDa and 80 kDa). A similar but slight increase in H1 histone phosphorylation was observed with isoflurane and enflurane, less lipid soluble volatile anesthetics. These findings suggest that halothane may increase PKC-mediated phosphorylation by the modification of phospholipid membrane and affect membrane signal transduction of the nerve cell under the anesthetic state.

Animals↗

PubMed1990

Halothane impairs the bioenergetic functions of isolated rat liver mitochondria.

The effect of halothane, a potent and popular volatile anesthetic, on isolated rat liver mitochondria was examined. Halothane inhibited state 3 and dinitrophenol-induced uncoupled respiration with NAD(+)-linked substrates, but not with FAD-linked substrates, and did not affect the oxidation-reduction state of mitochondrial cytochromes. Moreover, halothane increased state 4 respiration and ATPase activity and decreased the extra-mitochrondrial pH change coupled to ATP synthesis. These results indicate that halothane impairs mitochondrial ATP production by interfering with both the electron transport from NAD+ to FAD and the coupling of oxidative phosphorylation. Halothane only slightly affected the membrane potential, which is commonly dissipated by typical classical uncouplers. Moreover, halothane inhibited both ATP-driven and respiration-driven Ca2+ accumulation in mitochondria and stimulated Ca2+ release from mitochondrial stores at concentrations higher than those at which it inhibited ATP production. These findings indicate that the uncoupling action of halothane is not classical. During halothane anesthesia, these mitochondrial abnormalities may contribute to hepatocyte dysfunctions.

Adenosine Triphosphatases↗

PubMed1990

Roles of muscularis mucosae and myofibroblasts in the healing process of acetic acid-induced ulcer.

The changes in the localization of FITC-phalloidin-positive smooth muscle cells and interstitial cells were studied in control and acetic acid-treated rat fundic mucosa. In the control rats, the FITC-phalloidin-positive cells mostly corresponded to the smooth muscle cells of the muscularis mucosae, and the arteriolar and venular smooth muscle cells. On the other hand, 1 week after the acetic acid treatment, the fluorescence of the smooth muscle cells of the muscularis mucosae disappeared and a large number of fluorescent interstitial cells, probably corresponding to myofibroblasts, appeared in the regenerated mucosal layer. Three weeks after the application, severely thickened fluorescent muscularis mucosae were formed and the fluorescence of the interstitial cells was rather decreased.

Acetates↗

PubMed1990

Increased de novo purine synthesis by insulin through selective enzyme induction in primary cultured rat hepatocytes.

The proliferative effect of insulin on de novo purine synthesis and on the expression of various enzymes of purine metabolism were studied in primary cultured rat hepatocytes. Insulin greater than 1.5 x 10(-8) M increased DNA and de novo purine synthesis to 260-390 and 270-420%, respectively, 24 and 8 h after the administration. Insulin at 1.5 x 10(-7) M increased the specific activity of amidophosphoribosyltransferase (ATase) to 154-180%, hypoxanthine-guanine phosphoribosyltransferase to 129%, and adenine phosphoribosyltransferase (APRT) to 205%, in contrast to unchanged xanthine dehydrogenase at 80%. Enzyme induction was supported by the results of kinetic analysis and the inhibition of the insulin-induced increase in enzyme activities by protein synthesis inhibitors. Insulin increased ATP to 127% and decreased AMP, ADP, 5'-guanylic acid (GMP), and guanosine 5'-diphosphate (GDP), respectively, to 73, 69, 73, and 69%. Insulin increased adenylate energy charge from 0.83 to 0.90 without changing total feedback inhibitory potential on ATase. No obvious increase of 5-phosphoribosyl-1-pyrophosphate supply was suggested, although its apparent availability for purine ribonucleotide synthesis was increased to 208-245%, reflecting mainly induced APRT activity to 205%. It is concluded that hepatocyte proliferation by insulin, as evidenced by purine metabolism, is mediated by the selective gene activation of anabolic enzymes and increased ATP as the basis to activate multiple metabolic pathways without remarkable changes of substrate availability or feedback inhibition.

Adenine Phosphoribosyltransferase↗

PubMed1990

Is macronodular liver cirrhosis an irreversible lesion? Changes in the intrahepatic micro-vasculature treated with estradiol benzoate in rats.

Estradiol benzoate (EB), a synthetic estrogen, was injected to macronodular cirrhotic rats, and the reversibility of the lesion was investigated. Macronodular liver cirrhosis (MNLC) was produced by use of carbon tetrachloride plus 3'-Me-DAB. In animals with no treatment, regenerative nodules remained unchanged during an eighteen-week observation period. Microangiograms showed markedly deranged intrahepatic microvasculatures, including an irregularly contoured vascular tree and rarefaction in the peripheral area. On the other hand, EB treatment exerted conspicuous efficacy on the above-mentioned intrahepatic microcirculatory disorder and on sinusoidal dilatation, which led the livers with MNLC to revert to almost normal appearance. It is concluded that EB provides a salutary effect on the intrahepatic microcirculatory system, by means of which MNLC can be shown to be a reversible lesion.

Animals↗

PubMed1990

Singlet oxygen production and photobiological effects of pinacyanol chloride on yeast Saccharomyces cerevisiae.

Photobiological activities of pinacyanol chloride (PC), which is known as a non-intercalating dye, were investigated. Irradiation of PC-sensitized yeast cells in the dark brought about marked decrease of survival and induction of "petites" which are respiration-deficient mutants caused by partial loss of mitochondrial deoxyribonucleic acid. Nuclear mutation represented by reversion from Trp- to Trp+ was also induced by photodynamic action of PC. This fact suggested photoactive dyes are not necessarily intercalated for inducing mitochondrial and nuclear mutation. Singlet oxygen production was determined in the photoirradiated PC solution by electron spin resonance spectrometry. Photobiological effects of PC might be brought about mainly by a type II photodynamic mechanism.

Carbocyanines↗

PubMed1990

Discrimination between endotoxin and (1----3)-beta-D-glucan using turbidimetric kinetic assay with Limulus amebocyte lysate.

A procedure for the Limulus amebocyte lysate (LAL) test discriminating between endotoxin and (1----3)-beta-D-glucan based on the turbidimetric kinetic method was proposed. Endotoxin and (1----3)-beta-D-glucan, which are elicitors of the activation of LAL, showed different reaction courses with this lysate. To analyze the difference in the reactions, two parameters, the maximum differential coefficient of the reaction (Dmax) and the reaction time required to obtain Dmax (Tp) were defined. The logarithmic plottings of Tp versus Dmax (Tp-Dmax plot) discriminated between endotoxin and (1----3)-beta-D-glucan. Endotoxin was measured with a standard curve plotting logarithmic endotoxin concentration versus Dmax (ET-Dmax plot). The endotoxin calculated from Dmax was less influenced by (1----3)-beta-D-glucan than that calculated from the usual gelation time. A small amount of endotoxin in a sample could be concealed by the addition of polymyxin B, which inhibited the activation of LAL by endotoxin. (1----3)-beta-D-glucan was measured without being affected by the presence of a small amount of endotoxin using LAL with polymyxin B. The following procedure is proposed as a LAL test to discriminate between endotoxin and (1----3)-beta-D-glucan. (1) Identify the main substance (endotoxin or (1----3)-beta-D-glucan) triggering the activation of LAL using the Tp-Dmax plot. (2) Use the appropriate method to measure the main substance: the ET-Dmax plot for endotoxin or the LAL with polymyxin B for (1----3)-beta-D-glucan.

Endotoxins↗

PubMed1990

[Measurement of endotoxin in blood products using an endotoxin-specific Limulus test reagent and its relation to pyrogenic activities in rabbit].

The amounts of endotoxin in commercial blood products were measured by the turbidimetric kinetic Limulus test with an ordinary reagent (LAL-HS) and a new endotoxin-specific reagent (LAL-ES). LAL-ES contains a sufficient amount of a water-soluble (1----3)-beta-D-glucan derivative as a blocker of the (1----3)-beta-D-glucan-mediated coagulation pathway in the reaction of the Limulus amebocyte lysate. The amounts of endotoxin in albumin and globulin products measured with LAL-ES agreed with pyrogenic activities in rabbits, but those measured with LAL-HS did not. Added endotoxin in the blood products was well recovered with LAL-ES, but that in some products was excessively recovered with LAL-HS. The amounts of endotoxin in diphtheria-pertussis-tetanus combined vaccines measured with LAL-HS and LAL-ES agreed with the pyrogenic activities in rabbits. The results suggested the existence of a false-positive substance like beta-glucan in the blood products but not in the vaccine. LAL-ES is more suitable for the detection of endotoxin in blood products than LAL-HS.

Animals↗

PubMed1990

Expression of hepatitis B surface antigen in Chang cells transfected with hepatitis B virus DNA.

To investigate hepatitis B virus (HBV) biology in vitro, the transfection of recirculized HBV DNA into Chang cell line was performed. Linear HBV DNA was isolated from recombinant HBV DNA, pHBR105, which includes the whole genome of HBV and was recirculized. Chang cells were transfected with this recirculized HBV DNA by the two different procedures of calcium/phosphate coprecipitation and electroporation. After the transfection, the presence of large nucleated cells with multinuclei and ground-glass cytoplasma were noticed and these cells seemed to proliferate faster than untreated Chang cells. Transient expression of hepatitis B virus surface antigen (HBsAg) was demonstrated in cytoplasma of transfected cells by indirect immunofluorescence. HBsAg was not detected in the culture supernatants by radioimmunoassay. The extra-chromosomal HBV DNA was detected in the transfected cells by both procedures 7 weeks after the transfection by Southern blot analysis but it was lost 4 weeks after that. It was demonstrated that it was possible to transfect Chang cells with HBV DNA and that DNA was functioning to express HBsAg transiently.

Cell Line↗

PubMed1990

[Development of an endotoxin-specific Limulus amebocyte lysate test blocking beta-glucan-mediated pathway by carboxymethylated curdlan and its application].

We developed a simple new endotoxin-specific assay method that uses Limulus amebocyte lysate (LAL) containing a sufficient amount of a water-soluble (1----3)-beta-D-glucan derivative as a blocker of the (1----3)-beta-D-glucan-mediated coagulation pathway. The addition of 0.1 mg/ml or more of carboxymethylated (1----3)-beta-D-glucan completely blocked the activation of LAL by (1----3)-beta-D-glucan itself. The assay of endotoxin was unaffected by the presence of 1 mg/ml carboxymethylated (1----3)-beta-D-glucan. Spiked endotoxin was recovered well from beta-glucans by the turbidimetric kinetic method with LAL containing 1 mg/ml of carboxymethylated (1----3)-beta-D-glucan. Besides, this new LAL formulation was applied for an endotoxin-specific assay by the conventional gel-clot method or the chromogenic method. Gram-negative bacteria were specifically detected by the turbidimetric kinetic method with the LAL formulation. This LAL formulation may be used for an endotoxin-specific assay not only in pharmacology but also in clinical microbiology.

Bacteria↗

PubMed1990

Lidocaine inhibits stimulation-coupled responses of neutrophils and protein kinase C activity.

The effects of lidocaine, a local anesthetic, on various stimulation-coupled responses of neutrophils were studied. Superoxide generation, generation of chemiluminescence, depolarization of membrane potential and transitional increase in intracellular Ca2+ were inhibited by lidocaine in a concentration dependent manner. Lidocaine also inhibited Ca(2+)-activated phospholipid-dependent protein kinase (PKC) in the presence of various concentrations of Ca2+, phosphatidylserine and dioleoylglycerol. For the inhibition of all these stimulation-coupled responses, a similar order of the lidocaine concentration was needed. As in the case of dibucaine (Mori, T., Takai, Y., Minakuchi, R., Yu, B. and Nishizuka, Y., J. Biol. Chem. 255:8378-8380, 1980), lidocaine inhibited PKC activity in a manner competitive with phosphatidylserine. Lidocaine also inhibited the phosphorylation of 47 kDa neutrophil cytosplasmic protein, a phosphorylated protein required for NADPH oxidase activation. Thus, the cellular membrane phospholipid may be one of the target sites of lidocaine for the inhibitory action on the various stimulation-coupled responses of neutrophils, and these effects of lidocaine may correlate with its inhibitory action on PKC activity.

Animals↗