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Biomedical subjects

E Furuya

Publications and source records attributed to E Furuya.

At least 55 records · Page 3Linked to original sources
PubMed1985

Management of inflammation: lipid peroxide as a parameter for a better understanding of inflammatory processes.

The management of inflammation, based on an overall, coordinated observation of the inflammatory system, requires the assessment of the validity and biological significance of the various components in inflammation, a procedure that is more reliable than the interpretation of individual measurements in isolation. Such an overall approach, here developed from the model of carrageenin-induced inflammation, also predicates that lysosomal enzymes, lipid peroxide and proamidase (related, respectively, to the inflammatory response in a narrow sense, to tissue damage and to tissue repair) are three basic parameters required when studying inflammatory processes. This overall approach, moreover, shows that the inflammatory process must be regarded as being diachronic, and that in the light of the observation of exudate fluid it can be divided into three main stages, namely an early stage of exudation related to lipid peroxide, an intermediate stage of exudate dilution related to granuloma amidase, and a later stage of exudate concentration related to granuloma amidase and plasma protein.

Amidohydrolases↗
PubMed1985

Management of inflammation: proamidase as a parameter for a better understanding of inflammatory processes.

Coordinated observation of various factors in the inflammatory system and their relations shows that the levels of proamidase in granuloma pouch fluid in carrageenin-induced inflammation increase during the healing process whereas the proamidase shows (1) remarkably low values in rats injected with high doses of carrageenin, (2) low values in the earlier stages of inflammation with tissue damage (high values of fluid lipid peroxide and lactate dehydrogenase) and with phagocytosis (high values of fluid peroxidase and beta-glucuronidase), and (3) high values in the later stages where wound healing is progressing (high values of protein in plasma, fluid and granuloma pouch tissue and low values of fluid volume, fluid peroxidase, beta-glucuronidase and pouch tissue weight). In short, proamidase shows low values in the stage of tissue damage and constantly increasing values during the process of healing. Thus the measurement of proamidase, which reflects the degree of wound healing, provides an important parameter for a broad, coordinated observation of the inflammatory process, and may enable the management of inflammation.

Amidohydrolases↗
PubMed1985

Streptozotocin diabetes: prolonged inflammatory response with delay in granuloma formation.

Inflammatory responses to carrageenin in streptozotocin-induced diabetic rats proved to be characterized by low values of granuloma tissue (tissue) weight and granuloma pouch fluid (fluid) volume, high values of fluid beta-glucuronidase (beta-Gl) and leucine aminopeptidase (LAP), and furthermore by high values of fluid lipid peroxide (LPO) and lactate dehydrogenase (LDH) and low values of fluid proamidase. These results in such diabetic rats were similar to those in rats injected with high doses of carrageenin except tissue weight and fluid volume. On the basis of measurements of three basic parameters required for coordinated observation of the inflammatory system, namely lysosomal enzymes, LPO, and proamidase (related respectively to the inflammatory response sensu stricto, to tissue damage, and to tissue repair), it can be concluded that the diabetic rats show an inadequately adapted inflammatory response, with decreased granuloma formation and reduced exudation, to noxious agents. This is probably due to a low sensitivity of the inflamed tissue in diabetic rats to noxious stimuli or chemical mediators, leading to a delay in the normal defence reaction of enhanced granuloma formation and exudation, thus resulting in a prolonged inflammatory response with a delay in wound healing.

Amidohydrolases↗
PubMed1983

Effects of single moxibustion on phagocytic activity in mice.

Effects of moxibustion stimulation on the phagocytic activity of the reticuloendothelial system in ddY and ICR mice has been studied by using the carbon clearance methods. It was found that moxibustion stimulation induced the enhancement of the phagocytic activity with increased phagocytic indexes (K and a indexes) and lysosomal enzyme activities in mice peritoneal exudate cells and peritoneal macrophages. In addition, the increase of carbon uptake in the Kupffer cells of the liver after carbon injection can be seen by light microscopy when compared with that of nontreated mice. Few big holes on the cell surface of the macrophages obtained from the moxibustion mice were observed in scanning electron microscopical studies. These results suggest that the moxibustion treatment caused the enhancement of the host defence mechanisms in mice.

Animals↗
PubMed1982

Fructose-2,6-P2, chemistry and biological function.

A new activator of phosphofructokinase, which is bound to the enzyme and released during its purification, has been discovered. Its structure has been determined as beta-D Fructose-2,6-P2 by chemical synthesis, analysis of various degradation products and NMR. D-Fructose-2,6-P2 is the most potent activator of phosphofructokinase and relieves inhibition of the enzyme by ATP and citrate. It lowers the Km for fructose-6-P from 6 mM to 0.1 mM. Fructose-6-P,2-kinase catalyzes the synthesis of fructose-2,6-P2 from fructose-6-P and ATP, and the enzyme has been partially purified. The degradation of fructose-2,6-P2 is catalyzed by fructose-2,6-bisphosphatase. Thus a metabolic cycle could occur between fructose-6-P and fructose-2,6-P2, which are catalyzed by these two opposing enzymes. The activities of these enzymes can be controlled by phosphorylation. Fructose-6-P,2-kinase is inactivated by phosphorylation catalyzed by either cAMP dependent protein kinase or phosphorylase kinase. The inactive, phospho-fructose-6,P,2-kinase is activated by dephosphorylation catalyzed by phosphorylase phosphatase. On the other hand, fructose-2,6-bisphosphatase is activated by phosphorylation catalyzed by cAMP dependent protein kinase. Investigation into the hormonal regulation of phosphofructokinase reveals that glucagon stimulates phosphorylation of phosphofructokinase which results in decreased affinity for fructose-2,6-P2 appears to be due to the decreased synthesis by inactivation of fructose-2,6-P2,2-kinase and increased degradation as a result of activation of fructose-2,6-bisphosphatase. Such a reciprocal change in these two enzymes has been demonstrated in the hepatocytes treated by glucagon and epinephrine. The implications of these observations in respect to possible coordinated controls of glycolysis and glycogen metabolism are discussed.

Enzyme Activation↗
PubMed1982

Regulation of fructose-6-phosphate 2-kinase by phosphorylation and dephosphorylation: possible mechanism for coordinated control of glycolysis and glycogenolysis.

The kinetic properties and the control mechanism of fructose-6-phosphate 2-kinase (ATP: D-fructose-6-phosphate 2-phosphotransferase) were investigated. The molecular weight of the enzyme is approximately 100,000 as determined by gel filtration. The plot of initial velocity versus ATP concentration is hyperbolic with a Km of 1.2 mM. However, the plot of enzyme activity as a function of fructose-6-phosphate is sigmoidal. The apparent K0.5 for fructose-6-phosphate is 20 microM. Fructose-6-phosphate 2-kinase is inactivated by the catalytic subunit of cyclic AMP-dependent protein kinase, and the inactivation is closely correlated with phosphorylation. The enzyme is also inactivated by phosphorylase kinase in the presence of Ca2+ and calmodulin. The phosphorylated fructose-6-phosphate 2-kinase, which is inactive, is activated by phosphorylase phosphatase and alkaline phosphatase. The possible physiological significance of these observations in the coordinated control of glycogen metabolism and glycolysis is discussed.

Calcium↗
PubMed1982

The significance of measurements of lipid peroxide and a newly-discovered amidase in inflammation.

Inflammation is a biological defence mechanism against noxious stimuli. Over-strong and oversuppressed inflammatory responses both lead to tissue damage and delay of tissue repair. Determination of inflammatory responses on the basis of chemical mediators, however, only informs about the degree of these responses themselves. It cannot show whether these responses are over-strong or oversuppressed. We have developed a prototype standard for safe judgement of the appropriateness of inflammatory responses: measurements of lipid peroxide (a product of tissue damage) and a newly-discovered amidase (related to wound healing).

Amidohydrolases↗
PubMed1981

The effect of natural and synthetic D-fructose 2,6-bisphosphate on the regulatory kinetic properties of liver and muscle phosphofructokinases.

The effect of natural "activation factor" and synthetic fructose-2,6-P2 on the allosteric kinetic properties of liver and muscle phosphofructokinases was investigated. Both synthetic and natural fructose-2,6-P2 show identical effects on the allosteric kinetic properties of both enzymes. Fructose-2,6-P2 counteracts inhibition by ATP and citrate and decreases the Km for fructose-6-P. This fructose ester also acts synergistically with AMP in releasing ATP inhibition. The Km values of liver and muscle phosphofructokinase for fructose-2,6-P2 in the presence of 1.25 mM ATP are 12 milliunits/ml (or 24 nM) and 5 milliunits/ml (or 10 nM), respectively. At near physiological concentrations of ATP (3 mM) and fructose-6-P (0.2 mM), however, the Km values for fructose-2,6-P2 are increased to 12 microM and 0.8 microM for liver and muscle enzymes, respectively. Thus, fructose-2,6-P2 is the most potent activator of the enzyme compared to other known activators such as fructose-1,6-P2. The rates of the reaction catalyzed by the enzymes under the above conditions are nonlinear: the rates decelerate in the absence or in the presence of lower concentrations of fructose-2,6-P2, but the rates become linear in the presence of higher concentrations of fructose-2,6-P2. Fructose-2,6-P2 also protects phosphofructokinase against inactivation by heat. Fructose-2,6-P2, therefore, may be the most important allosteric effector in regulation of phosphofructokinase in liver as well as in other tissues.

Adenosine Monophosphate↗
PubMed1981

The structure of "activation factor" for phosphofructokinase.

The "activation factor" for phosphofructokinase was shown by chemical analysis, by synthesis, and by 13C NMR spectroscopy to be beta-D-fructose-2,6-P2. This compound was prepared from D-fructose-1,2-cyclic 6-P2 by alkaline hydrolysis. D-Fructose-1,2-cyclic 6-P2 is ineffective in activating phosphofructokinase while synthetic D-fructose-2,6-P2 has the same specific activity toward phosphofructokinase as the "activation factor" isolated from rat liver, and it exhibits the same characteristics on paper and ion exchange chromatography. Acid treatment of both the synthetic and the natural product destroys the biological activity and yields 1 mol each of fructose-6-P and Pi; alkaline phosphatase treatment of the compound followed with acid hydrolysis yields fructose. The natural abundance 13C NMR spectra of the synthetically prepared and purified D-fructose-1,2-cyclic 6-P2 and D-fructose-2,6-P2 have been obtained and all resonances have been assigned. The spectra also show that both samples contain predominantly one anomer and the 13C chemical shifts and 31P-13C coupling constants are consistent only with the beta-anomer.

Animals↗
PubMed1981

A novel enzyme catalyzes the synthesis of activation factor from ATP and D-fructose-6-P.

We have recently discovered an activator for phosphofructokinase termed "activation factor" (Furuya, E., and Uyeda, K. (1980) Proc. Natl. Acad. Sci. U. S. A. 77, 5861-5864). In this paper, we investigated the enzyme responsible for its synthesis. We have found an enzyme from rat liver which catalyzes the formation of activation factor from fructose-6-P and ATP-Mg and it has been identified as fructose-2,6-P2. Fructose-1,6-P2, fructose-1-P, or fructose does not serve as a substrate. This enzyme has been partially purified and shown to be different from phosphofructokinase. Several lines of evidence indicate that the in vitro synthetic product is identical with chemically synthesized fructose-2,6-P2: (a) it is active in our assay for activation factor which is based on counteraction of ATP inhibition of phosphofructokinase; (b) it is acid labile as is fructose-2,6-P2; and (c) it shows the same mobility as synthetic fructose-2,6-P2 upon paper chromatography and the acid hydrolysis product has been identified as fructose-6-P. Thus, this new enzyme catalyzes the synthesis of the activation factor from fructose-6-P and ATP-Mg.

Adenosine Triphosphate↗