Azotaemic Inhibition of Organic Anion Transport in the Kidney of the Rat: Mechanisms and Characteristics

1971 ◽  
Vol 40 (2) ◽  
pp. 159-169 ◽  
Author(s):  
E. P. Orringer ◽  
F. R. Weiss ◽  
H. G. Preuss
Keyword(s):  
Rat Kidney ◽  
Organic Anion ◽  
Anion Transport ◽  
Renal Transport ◽  
Organic Anion Transport ◽  
Kidney Slices ◽  
Low Concentrations ◽  
The Media ◽  
High Concentrations

1. While azotaemic sera depressed the in-vitro Na-iodohippurate transport of rat kidney slices at any concentration, normal sera excited transport at low concentrations and depressed transport at high concentrations. The depression of transport by azotaemic sera was partially overcome by neomycin feeding in contrast to the depression by normal sera, which was not altered by neomycin feeding. 2. Plotting the reciprocal of sodium-iodohippurate accumulated by slices against the reciprocal of the media concentrations of sodium iodohippurate suggested that the depression of hippurate transport produced by normal and azotaemic sera was competitive in nature. 3. Normal sera slowed the efflux of Na-iodohippurate from kidney slices while azotaemic sera affected it very little. 4. The depression produced by normal and azotaemic sera and the stimulation produced by low concentrations of normal sera were seen with serum ultrafiltrates and dialysates, and after passage through cation exchange columns, but not anion exchange columns. 5. The effects on Na-iodohippurate accumulation by normal and azotaemic sera could be reproduced with metabolizable (lactate), and nonmetabolizable (hippurate) organic anions as well as combinations of these. 6. The implications of these observations on the altered renal transport of Na-iodohippurate produced by azotaemic and normal sera are discussed.

scholarly journals Effect of aluminium toxicity on the development of poplar (Populus tremula L. x P. alba L.) cultured in vitro

2014 ◽  
Vol 68 (4) ◽  
pp. 245-250 ◽  
Author(s):  
Krystyna Bojarczuk
Keyword(s):  
Aluminium Toxicity ◽  
Inhibitory Effect ◽  
Populus Tremula ◽  
Aluminium Chloride ◽  
Adventitious Bud ◽  
Aluminium Sulphate ◽  
Low Concentrations ◽  
The Media ◽  
High Concentrations

Adventitious bud cultures were established using vegetative buds from selected clones of poplar (<em>Populus tremula</em> L. x <em>P</em>. <em>alba</em> L.) as initial explants. For multiplication of shoots a modified Murashige and Skoog medium (MS) was used. Aluminium salts (aluminium sulphate and aluminium chloride) were added to the media. It was found that the pH of the medium had no effect on the development of cultures at low concentrations of nutrients (1/2 or 1/4 MS). Low concentrations of aluminium (Al 25mg•dm<sup>-3</sup> supplied as aluminium sulphate, Al 15 mg•dm<sup>-3</sup> as aluminium chloride) had no inhibitory effect on shoot development but decreased regeneration of adventitious roots. High concentrations of aluminium inhibited the development of shoots and roots, especially in a medium at pH 4.5. Microcuttings rooted in the highest percentage and formed the strongest rooting system on 1/4 strength MS medium at pH 4.5. It was found that there was no difference between the rooting of shoots excised from cultures cultivated with or without A1 in this medium at pH 5.5.

scholarly journals Effect of papaverine on organic anion transport in rat kidney cortical slices.

1984 ◽  
Vol 7 (5) ◽  
pp. 342-345
Author(s):  
MAYUMI NAKASHIMA ◽  
NAHOKO MIKURIYA ◽  
MUNEKAZU GEMBA
Keyword(s):  
Rat Kidney ◽  
Organic Anion ◽  
Anion Transport ◽  
Organic Anion Transport ◽  
Cortical Slices

Fluorescein transport in isolated proximal tubules in vitro: epifluorometric analysis

1990 ◽  
Vol 258 (1) ◽  
pp. F46-F51 ◽  
Author(s):  
L. P. Sullivan ◽  
J. A. Grantham ◽  
L. Rome ◽  
D. Wallace ◽  
J. J. Grantham
Keyword(s):  
External Medium ◽  
Organic Anion ◽  
Anion Transport ◽  
Proximal Tubules ◽  
Organic Anion Transport ◽  
Fluorescent Compound ◽  
Intact Cells ◽  
Anion Transport System ◽  
Collecting Tubules

An epifluorometric method was used to quantify the bidirectional fluxes of fluorescein across the basolateral surfaces of nonperfused rabbit tubule segments in vitro. Proximal S2 segments, but not cortical collecting tubules or cortical thick ascending limbs, accumulated fluorescein to levels in cytoplasm over 100-fold greater than in the external medium. The rate of intracellular fluorescein accumulation was dependent on the concentration of the ligand in the external bath. The apparent Km was 10 microM and the Vmax was 623 x 10(-6) mol.min-1.l-1. Probenecid and ouabain inhibited fluorescein accumulation. We conclude that fluorescein is transported into the cytoplasm of proximal tubules by basolateral mechanisms that share features in common with the classical organic anion system. This fluorescent compound offers some unique advantages for the study of the organic anion transport system in intact cells.

In Vitro Effects of Ethanol on Rabbit Platelet Aggregation, Secretion of Granule Contents, and Cyclic AMP Levels in the Presence of Prostacyclin

1989 ◽  
Vol 61 (02) ◽  
pp. 254-258 ◽  
Author(s):  
Margaret L Rand ◽  
Peter L Gross ◽  
Donna M Jakowec ◽  
Marian A Packham ◽  
J Fraser Mustard
Keyword(s):  
Cyclic Amp ◽  
Inhibitory Effect ◽  
Rabbit Platelet ◽  
Inhibitory Effects ◽  
Low Concentrations ◽  
Rabbit Platelets ◽  
High Concentrations ◽  
In Vitro Effects ◽  
Aggregation Of Platelets

SummaryEthanol, at physiologically tolerable concentrations, inhibits platelet responses to low concentrations of collagen or thrombin, but does not inhibit responses of washed rabbit platelets stimulated with high concentrations of ADP, collagen, or thrombin. However, when platelet responses to high concentrations of collagen or thrombin had been partially inhibited by prostacyclin (PGI2), ethanol had additional inhibitory effects on aggregation and secretion. These effects were also observed with aspirin- treated platelets stimulated with thrombin. Ethanol had no further inhibitory effect on aggregation of platelets stimulated with ADP, or the combination of ADP and epinephrine. Thus, the inhibitory effects of ethanol on platelet responses in the presence of PGI2 were very similar to its inhibitory effects in the absence of PGI2, when platelets were stimulated with lower concentrations of collagen or thrombin. Ethanol did not appear to exert its inhibitory effects by increasing cyclic AMP above basal levels and the additional inhibitory effects of ethanol in the presence of PGI2 did not appear to be brought about by further increases in platelet cyclic AMP levels.

Aggregation of Cat Platelets in Vitro

1970 ◽  
Vol 23 (03) ◽  
pp. 601-620 ◽  
Author(s):  
Th. B Tschopp
Keyword(s):  
Adenosine Monophosphate ◽  
Blood Collection ◽  
Base Line ◽  
Reversible Aggregation ◽  
Low Concentrations ◽  
Irreversible Aggregation ◽  
High Concentrations ◽  
Two Phases ◽  
Improved Technique

SummaryAggregation of cat platelets in the citrated plasma is examined by means of Born’s absorptiometer. A marked tendency of the platelets of this species to spontaneous aggregation necessitated first of all the development of an improved technique of blood collection.A hypothesis according to which 5-HT is released from the platelets, explains the absence of oscillations on the base line of the absorptiometer, the absence of platelet swelling, when ADP is added, and the effect of stirring on the aggregation curves in cat PRP. The average volume of cat platelets amounts to 10.46 μ3 when directly fixed in the blood, when fixed from PRP to 12.17 μ3, when fixed from stirred PRP to 13.51 μ3.In low concentrations (0.3-2 μM) ADP produce reversible aggregation; in narrowly restricted, individually dissimilar mean concentrations irreversible aggregation in two phases and in high concentrations, irreversible aggregation in one phase. Like ADP serotonin produces 2 phase irreversible aggregation in concentrations of 3-10 μM, but unlike ADP, the aggregation velocity decreases again with high 5-HT concentrations (>100 μM). Adrenaline does not produce aggregation and it is likely that adenosine and adenosine monophosphate inhibit the aggregation by serotonin but not by ADP. Species differences in the aggregation of human, rabbit and cat platelets are discussed.

scholarly journals Characteristics of bile salt uptake into skate hepatocytes

1994 ◽  
Vol 299 (3) ◽  
pp. 665-670 ◽  
Author(s):  
G Fricker ◽  
V Dubost ◽  
K Finsterwald ◽  
J L Boyer
Keyword(s):  
Substrate Specificity ◽  
Bile Salt ◽  
Transport System ◽  
Bile Salts ◽  
Organic Anion ◽  
Anion Transport ◽  
Organic Anion Transport ◽  
Salt Uptake ◽  
Anion Transport System ◽  
Alpha 7

The substrate specificity for the transporter that mediates the hepatic uptake of organic anions in freshly isolated hepatocytes of the elasmobranch little skate (Raja erinacea) was determined for bile salts and bile alcohols. The Na(+)-independent transport system exhibits a substrate specificity, which is different from the specificity of Na(+)-dependent bile salt transport in mammals. Unconjugated and conjugated di- and tri-hydroxylated bile salts inhibit uptake of cholyltaurine and cholate competitively. Inhibition is significantly greater with unconjugated as opposed to glycine- or taurine-conjugated bile salts. However, the number of hydroxyl groups in the steroid moiety of the bile salts has only minor influences on the inhibition by the unconjugated bile salts. Since the transport system seems to represent an archaic organic-anion transport system, other anions, such as dicarboxylates, amino acids and sulphate, were also tested, but had no inhibitory effect on bile salt uptake. To clarify whether bile alcohols, the physiological solutes in skate bile, share this transport system, cholyltaurine transport was studied after addition of 5 beta-cholestane-3 beta,5 alpha,6 beta-triol, 5 alpha-cholestan-3 beta-ol and 5 beta-cholestane-3 alpha, 7 alpha, 12 alpha-triol. These bile alcohols inhibit cholyltaurine uptake non-competitively. In contrast, uptake of 5 beta-cholestane-3 alpha,7 alpha,12 alpha-triol, which is Na(+)-independent, is not inhibited by cholyltaurine. The findings further characterize a Na(+)-independent organic-anion transport system in skate liver cells, which is not shared by bile alcohols and has preference for unconjugated lipophilic bile salts.

An evaluation of potential seed treatments to control Fusarium solani f.sp. phaseoli, the cause of foot and root rot of Phaseolus vulgaris

1977 ◽  
Vol 89 (1) ◽  
pp. 235-238 ◽  
Author(s):  
P. E. Russell ◽  
A. E. A. Mussa
Keyword(s):  
Phaseolus Vulgaris ◽  
Fusarium Solani ◽  
Root Rot ◽  
Similar Pattern ◽  
Fungal Growth ◽  
Systemic Fungicide ◽  
Product Concentration ◽  
Low Concentrations ◽  
High Concentrations

SummaryTwo systemic fungicides, benomyl and thiabendazole, were more active than the non-systemic fungicide Drazoxolon in inhibiting fungal growth in vitro. A similar pattern was obtained in glasshouse trials with benomyl and thiabendazole giving adequate protection at low concentrations while Drazoxolon was ineffective unless applied at 50% the commercial product concentration. A field trial using thiabendazole, Drazoxolon and a mixture of benomyl and thiram confirmed the glasshouse results.Some phytotoxicity was noticed with high concentrations of both benomyl and thiabendazole, but satisfactory disease control was achieved using fungicide concentrations which did not induce phytotoxicity.

scholarly journals Colchicine-binding protein of the liver. Its characterization and relation to microtubules.

1975 ◽  
Vol 66 (3) ◽  
pp. 609-620 ◽  
Author(s):  
C Patzelt ◽  
A Singh ◽  
Y L Marchand ◽  
L Orci ◽  
B Jeanrenaud
Keyword(s):  
High Speed ◽  
Specific Binding ◽  
Electrophoretic Analysis ◽  
Binding Activity ◽  
Low Concentrations ◽  
Electrophoretic Behavior ◽  
High Affinity Binding Site ◽  
High Concentrations

Colchicine-binding activity of mouse liver high-speed supernate has been investigated. It has been found to be time and temperature dependent. Two binding activities with different affinities for colchicine seem to be present in this high-speed supernate, of which only the high-affinity binding site (half maximal binding at 5 x 10(-6) M colchicine) can be attributed to microtubular protein by comparison with purified tubulin. Vinblastine interacted with this binding activity by precipitating it when used at high concentrations (2 x 10(-3) M), and by stabilizing it at low concentrations (10(-5) M). Lumicolchicine was found not to compete with colchicine. The colchicine-binding activity was purified from liver and compared with that of microtubular protein from brain. The specific binding activity of the resulting preparation, its electrophoretic behavior, and the electron microscope appearance of the paracrystals obtained upon its precipitation with vinblastine permitted its identification as microtubular protein (tubulin). Electrophoretic analysis of the proteins from liver supernate that were precipitated by vinblastine indicated that this drug was not specific for liver tubulin. Preincubation of liver supernate with 5 mM EGTA resulted in a time-dependent decrease of colchicine-binding activity, which was partly reversed by the addition of Ca++. However, an in vitro formation of microtubules upon lowering the Ca++ concentration could not be detected. Finally, a method was developed enabling that portion of microtubular protein which was present as free tubulin to be measured and to be compared with the total amount of this protein in the tissue. This procedure permitted demonstration of the fact that, under normal conditions, only about 40% of the tubulin of the liver was assemled as microtubules. It is suggested that, in the liver, rapid polymerization and depolymerization of microtubules occur and may be an important facet of the functional role of the microtubular system.

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