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At least 109 records · Page 6Linked to original sources
PubMed1984

Arginine-rich proteins in spherical inclusions of human locus coeruleus neurons demonstrated by benzil modification.

Previous studies have shown that aminergic neurons in the normal human brain contain acidophilic cytoplasmic inclusions--called protein bodies (PBs)--that are reduced or absent in parkinsonism and disrupted in depression. The purpose of the present study was to elucidate the constitution of PBs in five formalin-fixed normal human brains using histochemical methods specific for histones, protamines, and the amino acid arginine. PBs were revealed with alkaline fast green and bromphenol blue, exhibiting a high content in histones and in protamines. They developed blue metachromasia with phosphotungstic acid-hematoxylin and green fluorescence with phenanthrenequinone, which established the presence of arginyl residues. Using benzil, which selectively modifies the guanido group of arginine, staining was blocked for each of the above two methods. The application of Mallory's trichrome procedure after benzil differentiated the PBs into an unstained core and a still fuchsinophilic rim. Since the fuchsinophilia of the rim was shown to persist after acetylation as well, we suggest that this rim probably contains acidic macromolecules that attach to the basic charges of the amphoteric acid fuchsin. We conclude that the PB are complex structures consisting of a core segregating arginine-rich proteins and a rim which probably contains macromolecules of an acidic nature.

Aldehydes↗
PubMed1986

The effect of temperature and pH on the stability of human pepsin in stored gastric juice. A method to prevent activity loss.

The mechanisms controlling pepsin secretion are controversial. A contributory factor may be storage-dependent effects. We have studied the effects of temperature, pH, and storage time on human gastric pepsin. Gastric juice samples taken from three healthy volunteers under both basal and post-pentagastrin-stimulated (6 micrograms/kg subcutaneously) conditions were separated into four aliquots. Each aliquot was titrated to pH 1, 4, or 6 or left at ambient pH. Aliquots were then stored at 4 degrees C or frozen at -70 degrees C and stored. On days 1, 3, 7, and 28 aliquots were removed and assayed by the kinetic albumin-bromphenol blue method. In a second experiment we determined the effects of different concentrations of glycerol on the preservation of peptic activity. From these experiments we conclude that pepsin is unstable when stored frozen at low pH but not when stored above pH 2. This pH-dependent stability may explain the variable conclusions other workers report on optimal methods of storing gastric juice. In addition, we have confirmed the suitability of glycerol as a preservative of peptic activity and recommend that gastric juice be stored frozen with 11.5% glycerol.

Cold Temperature↗
PubMedDate not supplied

Application of membrane filters for spectrophotometric determination of cationic surfactants in river water and sediment.

Cationic surfactant (CS+) in urban river water and sediment was extracted and determined spectrophotometrically with 2 membrane filters. The CS+ in the water samples, mostly in the form of an ion associate with the coexisting anionic surfactant (AS), was collected on a polytetrafluoroethylene (PTFE) membrane filter and eluted with methanol. Bromphenol blue (BPB), hydrochloric acid, and water were added to the methanol solution successively, and the mixed solution was filtered through a mixed cellulose ester membrane filter. The CS+-BPB- ion associate, formed by a counter ion exchange, was collected on the filter and dissolved into N,N-dimethylformamide (DMF) together with the mixed cellulose ester membrane filter. After addition of 2 drops of triethanolamine, the absorbance of the DMF solution was measured. The CS+ in sediment samples was extracted with methanol by ultrasonic irradiation; the methanol solution was then passed through a PTFE membrane filter and evaporated to dryness. The CS+ was redissolved in a small amount of methanol. For water samples, recoveries and relative standard deviations for 0.30 microM benzyldimethyl-tetradecylammonium ion, a standard material, were > or =93 and < or =5%, with a detection limit of 0.02 microM. Concentrations of CS+ in sediments were much higher than those in water samples, indicating that CS+ is adsorbed on the surface of the sediment.

Adsorption↗
PubMed1976

Active transport of phenol red by rat lung slices.

32S-phenol red was taken up by rat lung slices incubated in oxygenated Krebs-Ringer phosphate-glucose solution (pH 7.4) at 37 degrees C by a process showing the characteristics of active transport. Uptake against a concentration gradient occurred by a saturable process that was inhibited by low temperature, anaerobic conditions and certain metabolic inhibitors. Phenol red uptake was depressed in the presence of certain anionic dyes, such as chlorphenol red, bromphenol blue, bromthymol blue and bromcresol green, and by various other organic acids, including disodium cromoglycate, probenecid, cephalothin and benzylpenicillin. In contrast, isoniazid and p-aminohippuric acid had no effect on phenol red uptake, suggesting that a specificity exists in the rat lung for transport of anionic compounds. Interestingly, in the presence of paraquat, an organic cation,phenol red uptake was increased. The extent of uptake of phenol red by lung slices was dependent on levels of Na, K and Ca ion in the incubation medium as well as on the thickness of the tissue slice. Phenol red was bound to lung homogenates; however, the characteristics of the binding were such that binding alone could not account for accumulation by lung slices.

Animals↗
PubMed1990

Differentiating various abnormalities of thyroxin binding to serum proteins by radioelectrophoresis of thyroxin and immunoassay of binding proteins.

Using the simple method of protein analysis described here, we could identify thyroxin (T4)-binding-protein abnormalities in euthyroid patients with hyperthyroxinemia or hypothyroxinemia. Serum incubated with [125I]thyroxin was analyzed by agarose gel electrophoresis, with bromphenol blue staining of protein. The relative distribution of radioactive T4 was determined for each binding protein--thyroxin-binding globulin (TBG), transthyretin, albumin, and T4-binding immunoglobulin (when present)--and the mass of T4 bound to each was determined. We also used sensitive immunoassays to quantify TBG, transthyretin, and albumin concentrations, then calculated the mass of T4 (as determined by electrophoresis) bound per unit mass of the respective binding protein. When the concentration of binding proteins was altered (e.g., TBG excess or TBG deficiency), the T4 binding/mass ratio for each protein remained within the expected range; but when the functional affinity of a binding protein was altered--as in dysalbuminemic hyperthyroxinemia and in low-T4 nonthyroidal illness--this ratio was abnormal. This procedure can be used to help identify TBG excess, TBG deficiency, dysalbuminemic hyperthyroxinemia, prealbumin-associated hyperthyroxinemia, variant TBG with reduced affinity for T4, euthyroid sickness, and T4-binding autoantibodies.

Autoantibodies↗
PubMedDate not supplied

Competition for binding to multiple sites of human serum albumin for cholecystographic agents and sulfobromophthalein.

The binding of two cholecystographic agents, iophenoxate and iopanoate, to human serum albumin was studied with 11 putative competitors; the results were qualitatively consistent with competitive binding to common sites. A more precise analysis of competition was achieved with four pairs of compounds for which the free and bound concentration of each was determined. The results were analyzed by a computer program and the dissociation constants calculated for both binder and competitor at specified sites on albumin. With numbering based on the rank order of dissociation constants for iophenoxate, the highest binding of the four compounds occurs at different sites: iophenoxate at site I; iopanoate at site II, sulfobromophthalein at site III; and bromphenol blue at site II. For a given compound, there is close agreement in the calculated affinities at different sites regardless of the competitor.

Binding Sites↗
PubMed1977

[Comparative thin-layer chromatographic studies for determining phorate and fenthion].

Experiments were carried out to use thin-layer chromatography to determine pure substances of the organic phosphorous insecticides forat and phenothion. Three sorbents were employed to establish the most appropriate conditions for the application of a fast, readily applicably and highly sensitive method--silica gel G, DG and Kiselgur "Merk", as well as 14 mobile phases--monocompound (n-hexane, n-heptane, acetone benzol and toluol), double combinations (hexane-acetone 4:1, hexane-acetone 9:1, hexane-benzol 1:1, hexane-benzol 4:1, heptane-acetone 7:1, benzol-hexane 4:1, benzol-acetone 9:1, and petrolium ether-tetrachlormethane) and triple combinations (acetone-toluol-hexane 1:15 and 5 developers (a diazosalt, bromine vapours + diazosalt, palladium bichloride, bromphenol blue, and silver nitrate, sodium hydroxide, ammonia gas). Established was the fact that the best results are obtained with the use of silica gel G, the mobile phase heptan-acetone 7:1, and the developer of 0.2% solution of palladium bichloride in 0.5 per cent solution of hydrochloric acid. In chromatogrammes the forat compound appears as a tile red portion with a darker peripheral part and Rf = 0.61, and phenothion--in yellow, with a brownish halo and Rf = 0.41. The method is highly sensitive--for forat 0.5 microgram, and for phenothion 0.5 microgram. In determining these insecticides it is possible to use as a sorbent silica gel "Merk" 1:1 with the same degree of sensitivity, but with higher Rf values.

Chromatography, Thin Layer↗
PubMed1976

The flagellar membrane of Ochromonas danica. Isolation and electrophoretic analysis of the flagellar membrane, axonemes, and mastigonemes.

The isolation and purification of the flagellar membrane of the phytoflagellate, Ochromonas danica, is described. The procedure is simple, mild, rapid, and it produces a pure membrane preparation. The method additionally permits the isolation of clean preparations of axonemes and mastigonemes from a single flagella preparation. Each component was studied by electron microscopy and acrylamide gel electrophroesis. The isolated flagella preparation was nearly free of other cellular organelles as judged by phase contrast and electron microscopy. The purified membrane preparation consisted of small vesicles (500 to 1500 A in diameter) with a trilamellar pattern about 80 A thick. Isolated membrane was analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, displaying five major protein bands, five minor protein bands, and some protein which remained at the origin. The five major protein components had apparent molecular weights of 54,000, 47,000, 35,000, 31,000, and 28,000. All mastigoneme protein components are glycoproteins as judged by periodic acid-Schiff staining. The mastigoneme preparation contained three major protein bands. Two of them were revealed as doublets and migrated with an average velocity corresponding to 83,000 delatons, the other major protein band migrated with a velocity corresponding to 54,000 daltons. A heavy carbohydrate band is seen near the bromphenol blue tracking dye. The axoneme preparation showed one major protein band having an apparent molecular weight of about 54,000 and some proteins having high molecular weights which remained on top of the polyacrylamide gel.

Animals↗
PubMed1976

[Inhibition of exogenous lactate dehydrogenase in mammalian ova].

A technique of microinjection of exogenic commercial lactate dehydrogenase into the zygotes of rats has been elaborated. A selective inhibition of exogenous LDH-3, LDH-4 and LDH-5 was registered in the ova-recipients. Attempts to reproduce the selective inhibition of LDH-3, LDH-4 and LDH-5 by a microhomogenate made of zygotes were not successful. The identification of LDH from ovocytes and exogenic LDH was made according to their electrophoretic mobility relative to Bromphenol blue and LDH-1.

Animals↗
PubMed1981

Improvement of the parallel flow dialysis technique for the detection of drug-binding proteins in column effluents.

The parallel flow dialysis technique was improved for application to the detection of drug-binding proteins in a column chromatographic effluent. To prevent the baseline drift, the pressures of both protein and drug channels were maintained equal during chromatography, and Brij-35 was added to the solvents. The improved method was successfully applied to the detection of methyl orange-binding proteins in human serum and bromphenol blue-binding proteins in rat liver homogenate.

Animals↗
PubMed1990

Binding of bromophenol blue to bovine serum albumin and its succinylated forms.

Interaction of bromophenol blue with bovine serum albumin and its five succinylated forms was studied spectrophotometrically at three different ionic strengths, i.e. 0.04, 0.15 and 1.0 and at two different pH values, namely pH 7.0 and pH 5.0 respectively. Results showed a decrease in bromophenol blue binding on increasing succinylation at low ionic strengths. This decrease was more marked at pH 7.0 than pH 5.0. However, at both the pH values binding returned to a significant degree on increasing the ionic strength to 1.0. Succinylation also caused marked conformational changes at pH 7.0 and ionic strength 0.15 as evidenced by changes in hydrodynamic properties and reduction in antigen-antibody precipitin reaction. However, an increase in ionic strength to 1.0 or decrease in pH to 5.0 caused significant reversal in hydrodynamic parameters. These studies show that lysine residues of bovine serum albumin are not important in bromophenol blue binding.

Bromphenol Blue↗