Compartmented pyruvate in perfused working heart

1985 ◽  
Vol 249 (3) ◽  
pp. H439-H449 ◽  
Author(s):  
R. Bunger
Keyword(s):  
Specific Activity ◽  
High Specific Activity ◽  
Inhibitory Effect ◽  
Quantitative Agreement ◽  
Myocardial Substrate ◽  
14Co2 Production ◽  
The Mean ◽  
Glycerol 3 Phosphate Dehydrogenase ◽  
Perfused Hearts ◽  
Working Heart

Pyruvate compartmentation and lactate dehydrogenase (LDH) were studied in isolated perfused working guinea pig hearts. The mean intracellular pyruvate (Pyr) contents increased with perfusate Pyr (0-2 mM) but varied only slightly with glucose (0-10 mM) and additional insulin (0.04-5 U/l), respectively. With 5-10 mM glucose plus 5 U/l insulin, but not with Pyr or lactate (Lac) as substrates, a near equilibrium between the LDH and the glycerol-3-phosphate dehydrogenase seemed to exist. Evidence for an inhibitory effect of Pyr on the activity of the LDH system of the perfused hearts was not obtained. With [U-14C]glucose as sole substrate, the specific activity of coronary venous Lac was near half that of precursor glucose. 14CO2 production was thus in quantitative agreement with rates of pyruvate oxidation that were determined as glucose uptake minus (Pyr + Lac) release. In contrast, with 0.2 mM [1-14C]Pyr plus 5 mM glucose, the ratio of 14CO2 production to specific activity of Lac overestimated Pyr oxidation judged from myocardial substrate balances and O2 uptake, respectively; here, at least three pools of [14C]HCO-3 and [14C]lac, respectively, were kinetically demonstrable during washout of trace amounts of 14C-labeled Pyr. Evidently, the specific activity of Lac was equivalent to that of mitochondrial oxidized Pyr provided [14C]glucose was the sole or major precursor of cellular pyruvate. However, exogenously applied [1-14C]Pyr of high specific activity seemed to induce intracellular formation of both a highly and lowly labeled Pyr; the latter Pyr compartment did not seem in ready equilibrium with the cell physiologically prevailing highly labeled Pyr pool.

scholarly journals THE MECHANISM OF COLCHICINE INHIBITION OF MITOSIS

1965 ◽  
Vol 25 (1) ◽  
pp. 145-160 ◽  
Author(s):  
Edwin W. Taylor
Keyword(s):  
Cell Cycle ◽  
Mitotic Spindle ◽  
Specific Activity ◽  
High Specific Activity ◽  
Quantitative Agreement ◽  
Direct Effects ◽  
Macromolecular Synthesis ◽  
Reversible Binding ◽  
Maximum Value ◽  
Interphase Cells

H3-colchicine of high specific activity (2.5 curies per mM) was prepared in order to study the mechanism of colchicine inhibition of mitosis in cultures of human cells, strain K.B. No direct effects on the duration of the cell cycle or macromolecular synthesis were demonstrable at a concentration of colchicine which completely inhibited mitosis. The radioactive compound was bound to the cells at a rate proportional to colchicine concentration. The binding appeared to be reversible since the radioactivity of the cells reached a maximum value for a given concentration and was slowly lost after resuspension of the cells in fresh medium. A suitable exposure to colchicine produced accumulation of metaphase-blocked mitoses after the colchicine was removed from the medium. An exposure of 6 to 8 hours at 10-7 M was sufficient to block essentially all the cells in metaphase, thus indicating that colchicine is bound to the majority of interphase cells. The data are in quantitative agreement with a mechanism involving reversible binding of colchicine to a set of cellular sites. Based on the correlation between the time of first appearance of blocked mitoses and the radioactivity per cell, it is suggested that if a critical fraction (3 to 5 per cent) of the sites are complexed, the cell is unable to form a functional mitotic spindle.

scholarly journals Brief Report: Lack of Effect of L-Methionine Ingestion on 14CO2 Excretion from L-Histidine (Imidazole-2-14C) in Folic Acid and Vitamin B12 Deficient Humans

Blood ◽  
1970 ◽  
Vol 35 (1) ◽  
pp. 86-89 ◽  
Author(s):  
HANNES B. STAHELIN ◽  
H. S. WINCHELL ◽  
N. KUSUBOV
Keyword(s):  
Body Weight ◽  
Folic Acid ◽  
Vitamin B12 ◽  
Specific Activity ◽  
Human Subjects ◽  
Vitamin B12 Deficiency ◽  
High Specific Activity ◽  
Inhibitory Effect ◽  
B12 Deficiency ◽  
Cell Membrane Transport

Abstract Three human subjects with folic acid and one with vitamin B12 deficiency failed to show any effect of ingestion of L-methionine (400-800 µg./kg. body weight) on the production of 14CO2 from parenterally administered high specific activity L-histidine (imidazole-2-14C). It is suggested that the inhibitory effect of methionine on intestinal absorption and cell membrane transport of histidine can explain previously published effects of methionine on the oxidation of the imidazole-2 carbon atom of L-histidine and that a direct effect of methionine on histidine metabolism need not be invoked.

scholarly journals Involvement of Carnosic Acid in the Phytotoxicity of Rosmarinus officinalis Leaves

Toxins ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 498 ◽  
Author(s):  
Kwame Appiah ◽  
Hossein Mardani ◽  
Richard Omari ◽  
Vincent Eziah ◽  
John Ofosu-Anim ◽  
...  
Keyword(s):  
Specific Activity ◽  
Control Measure ◽  
High Specific Activity ◽  
Total Activity ◽  
Inhibitory Effect ◽  
Rosmarinus Officinalis ◽  
Carnosic Acid ◽  
High Concentration ◽  
Crude Extracts ◽  
Test Plants

Weeds are rapidly developing resistance to synthetic herbicides, and this can pose a threat to the ecosystem. Exploring allelopathic species as an alternative weed control measure can help minimize the ecological threat posed by herbicide-resistant weeds. In this study, we aimed to evaluate the contribution of some polyphenols to the allelopathy of rosemary (Rosmarinus officinalis L.). The phytotoxic effects of rosemary (leaves, roots, inflorescences, and stems) crude extracts were tested on lettuce (Lactuca sativa L.). Soils incorporated with dried rosemary leaves were also tested on test plants. Reversed-phase high-performance liquid chromatography (HPLC) analysis was used to determine the content of some polyphenols (caffeic, ferulic, gallic, rosmarinic, carnosic, and chlorogenic acids) in rosemary. The specific activity and total activity of crude extracts and individual compounds were evaluated using lettuce. The crude extract of rosemary leaves showed the highest growth inhibitory effect among the rosemary organs tested. Soil amended with rosemary leaf debris reduced the dry matter and seed emergence of lettuce. Carnosic acid was the main compound detected in rosemary leaves and had a high specific activity when tested on lettuce. During the seed germination period, there was observed filter paper coloration among the test plants treated with carnosic acid (250 μg/mL). The high concentration and strong inhibitory effect of carnosic acid could explain the inhibitory activity of the rosemary leaf extract. Hence, we conclude based on the total activity estimation that carnosic acid among the other tested compounds is the major allelochemical in rosemary leaves.

scholarly journals High Specific Activity of Radium Isotopes in Baryte from the Czech Part of the Upper Silesian Basin—An Example of Spontaneous Mine Water Treatment

Minerals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 103
Author(s):  
Jakub Jirásek ◽  
Dalibor Matýsek ◽  
Petr Alexa ◽  
Michal Osovský ◽  
Radim Uhlář ◽  
...  
Keyword(s):  
Bituminous Coal ◽  
Specific Activity ◽  
Drainage System ◽  
High Specific Activity ◽  
Water Drainage ◽  
Mine Waters ◽  
Radium Isotopes ◽  
Mill Tailings ◽  
The Mean ◽  
Sample Method

Radium-bearing barytes (radiobarytes) have been known since the beginning of the 20th century. They are mainly found as precipitates of low-temperature hydrothermal solutions. In anthropogenic environments, they frequently occur as crusts on oil industry equipment used for borehole extraction, in leachates from uranium mill tailings, and as a by-product of phosphoric acid manufacturing. Recently, we recognized Ra-rich baryte as a precipitate in the water drainage system of a bituminous coal mine in the Czech part of the Upper Silesian Basin. The precipitate is a relatively pure baryte, with the empirical formula (Ba0.934Sr0.058Ca0.051Mg0.003)Σ1.046S0.985O4.000. The mean specific activity of 226Ra was investigated by the two-sample method and it equals 39.62(22) Bq/g, a level that exceeds known natural occurrences. The values for 228Ra and 224Ra are 23.39(26) Bq/g and 11.03(25) Bq/g. The radium content in the baryte is 1.071 ng/g. It is clear that the Ra-rich baryte results from the mixing of two different mine waters—brines rich in Ba, Sr, and isotopes 226Ra and 228Ra and waters that are affected by sulfide weathering in mine works. When this mixing occurs in surface watercourses, it could present a serious problem due to the half-life of 226Ra, which is 1600 years. If such mixing spontaneously happens in a mine, then the environmental risks will be much lower and will be, to a great, extent eliminated after the closure of the mine.

scholarly journals Phospholipase A2 enzyme from the venom of Egyptian honey bee Apis mellifera lamarckii with anti-platelet aggregation and anti-coagulation activities

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Doaa A. Darwish ◽  
Hassan M. M. Masoud ◽  
Mohamed M. Abdel-Monsef ◽  
Mohamed S. Helmy ◽  
Hind A. Zidan ◽  
...  
Keyword(s):  
Apis Mellifera ◽  
Platelet Aggregation ◽  
Phospholipase A2 ◽  
Honey Bee ◽  
Specific Activity ◽  
Deae Cellulose ◽  
High Specific Activity ◽  
Inhibitory Effect ◽  
Bee Venom ◽  
Very High

Abstract Background Honey bee venom contains various enzymes with wide medical and pharmaceutical applications. Results The phospholipase A2 (PLA2) has been apparently purified from the venom of Egyptian honey bee (Apis mellifera lamarckii) 8.9-fold to a very high specific activity of 6033 U/mg protein using DEAE–cellulose and Sephacryl S-300 columns. The purified bee venom PLA2 is monomeric 16 kDa protein and has isoelectric point (pI) of 5.9. The optimal activity of bee venom PLA2 was attained at pH 8 and 45 °C. Cu2+, Ni2+, Fe2+, Ca2+, and Co2+ exhibited a complete activating effect on it, while Zn2+, Mn2+, NaN3, PMSF, N-Methylmaleimide, and EDTA have inhibitory effect. Conclusions The purified bee venom PLA2 exhibited anti-platelet aggregation and anti-coagulation activities which makes it promising agent for developing novel anti-clot formation drugs in future.

Effects of Heparin Oligosaccharides with High Affinity for Antithrombin III in Experimental Venous Thrombosis

1982 ◽  
Vol 47 (03) ◽  
pp. 244-248 ◽  
Author(s):  
D P Thomas ◽  
Rosemary E Merton ◽  
T W Barrowcliffe ◽  
L Thunberg ◽  
U Lindahl
Keyword(s):  
Antithrombin Iii ◽  
Specific Activity ◽  
High Specific Activity ◽  
Factor Xa ◽  
Blood Levels ◽  
Thrombin Time ◽  
High Affinity ◽  
Very High

SummaryThe in vitro and in vivo characteristics of two oligosaccharide heparin fragments have been compared to those of unfractionated mucosal heparin. A decasaccharide fragment had essentially no activity by APTT or calcium thrombin time assays in vitro, but possessed very high specific activity by anti-Factor Xa assays. When injected into rabbits at doses of up to 80 ¼g/kg, this fragment was relatively ineffective in impairing stasis thrombosis despite producing high blood levels by anti-Xa assays. A 16-18 monosaccharide fragment had even higher specific activity (almost 2000 iu/mg) by chromogenic substrate anti-Xa assay, with minimal activity by APTT. When injected in vivo, this fragment gave low blood levels by APTT, very high anti-Xa levels, and was more effective in preventing thrombosis than the decasaccharide fragment. However, in comparison with unfractionated heparin, the 16-18 monosaccharide fragment was only partially effective in preventing thrombosis, despite producing much higher blood levels by anti-Xa assays.It is concluded that the high-affinity binding of a heparin fragment to antithrombin III does not by itself impair venous thrombogenesis, and that the anti-Factor Xa activity of heparin is only a partial expression of its therapeutic potential.

Autoprothrombin C Activity from Prothrombin with Snake Venom or Trypsin

1962 ◽  
Vol 08 (03) ◽  
pp. 425-433 ◽  
Author(s):  
Ewa Marciniak ◽  
Edmond R Cole ◽  
Walter H Seegers
Keyword(s):  
Snake Venom ◽  
Thrombolytic Agent ◽  
Sodium Citrate ◽  
Specific Activity ◽  
High Specific Activity ◽  
Citrate Solution ◽  
Clotting Factors ◽  
Activation Products ◽  
Russell’S Viper ◽  
Autoprothrombin C

SummarySuitable conditions were found for the generation of autoprothrombin C from purified prothrombin with the use of Russell’s viper venom or trypsin. DEAE chromatographed prothrombin is structurally altered and has never been found to yield autoprothrombin C and also did not yield it when Russell’s viper venom or trypsin were used. Autoprothrombin C is derived from prothrombin with tissue extract thromboplastin, but not in large amounts with the intrinsic clotting factors. With the latter thrombin and autoprothrombin III are the chief activation products. Autoprothrombin III concentrates were prepared from serum and upon activation with 25% sodium citrate solution or with Russell’s viper venom large amounts of autoprothrombin C were obtained, and this was of high specific activity. Theoretically trypsin is not a thrombolytic agent, but on the contrary should lead to intravascular clotting.

Simple explicit model of liquid mean flow in region above axial impeller

1985 ◽  
Vol 50 (11) ◽  
pp. 2396-2410
Author(s):  
Miloslav Hošťálek ◽  
Ivan Fořt
Keyword(s):  
Vortex Flow ◽  
Flow Model ◽  
Quantitative Agreement ◽  
Mean Flow ◽  
Flat Bottom ◽  
Proposed Model ◽  
Minimum Number ◽  
The Mean ◽  
Model Equations ◽  
Radial Circulation

The study describes a method of modelling axial-radial circulation in a tank with an axial impeller and radial baffles. The proposed model is based on the analytical solution of the equation for vortex transport in the mean flow of turbulent liquid. The obtained vortex flow model is tested by the results of experiments carried out in a tank of diameter 1 m and with the bottom in the shape of truncated cone as well as by the data published for the vessel of diameter 0.29 m with flat bottom. Though the model equations are expressed in a simple form, good qualitative and even quantitative agreement of the model with reality is stated. Apart from its simplicity, the model has other advantages: minimum number of experimental data necessary for the completion of boundary conditions and integral nature of these data.

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