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PubMedDate not supplied

Purification of kappa-casien glycomacropeptide from sweet whey with undetectable level of phenylalanine.

Glycomacropeptide (GMP) found in sweet whey is a biologically active compound released from kappa-casein by the action of chymosin during cheese making. This study was undertaken to purify GMP from sweet whey as a research chemical on a laboratory scale. Glycomacropeptide was isolated from proteins and other non-GMP compounds by deproteinization with trichloroacetic acid and gel chromatography on Sephacryl S-200. The purified GMP accounted for 0.12% of dry sweet whey powder and contained 107.0, 50.9, 61.2 and 4.3 microg, respectively, of sialic acid, galactose, galactosamine and phosphorus per mg dry weight. The GMP was of high purity, with its amino acid composition showing undetectable levels of phenylalanine, tyrosine and arginine, the amino acids that do not occur in bovine GMP. On gel electrophoresis, the GMP showed a single broad band with an average mobility faster than that of carbonic anhydrase (molecular weight = 31 kDa). The purified GMP may be used as a standard glycopeptide in chromatography and electrophoresis and may also be used to test various known or unknown properties and biological activities of this compound.

Amino Acids↗

PubMed1993

Effects of three kinds of topical eye-drops on the experimental rabbit dry eye.

We studied the ultrastructural changes of the corneal epithelium of the experimental rabbit dry eye and the effects of three topically applied eye-drops. Fourty rabbits were divided into experimental rabbit dry eye group, 0.1% bromhexine-treated group, 50% Chinese medicinal herb-treated group and 0.01% retinoic acid-treated group. Ten days after surgical removal of lacrimal gland, nictitating membrane and Harder's gland of the rabbit eyes, and corroding the conjunctiva with 50% trichloroacetic acid, the rabbit eyes showed typical dry eye signs. A lot of pathologic ultrastructural changes of the corneal epithelium were observed. Fourteen days after topically applying the three eye-drops, no significant effect was found on the ultrastructural changes of the dry eye corneal epithelium in the 0.1% bromhexine-treated and 50% Chinese medicinal herb-treated groups. However, in the 0.01% retinoic acid-treated eyes, normal microvilli and microplicae reappeared, denuded corneal epithelium was covered by new epithelial cells, no cell swelled, degenerated mitochondria recovered, basement membrane returned completely, and the completely recovered corneal epithelial cell count showed a significant difference compared with the control (P < 0.01). We conclude that removing the lacrimal gland, nictitating membrane and Harder's gland of rabbit eye, and corroding the conjunctiva with 50% trichloroacetic acid can result in rabbit dry eye and topically applying 0.01% retinoic acid can promote the recovery of the dry corneal epithelium.

Animals↗

PubMed1978

Elicitation of endotoxemic effects in C3H/HeJ mice with glucocorticoid antagonizing factor and partial characterization of the factor.

C3H/HeJ mice were used to study the origin and nature of endotoxin-induced glucocorticoid antagonizing factor (GAF). In conventional mice GAF is believed to be responsible for a variety of effects that occur as a result of an injection of endotoxin, including the inhibition of hormonal induction of hepatic phosphoenolpyruvate carboxykinase and of glyconeogenesis. Responses in such animals are seen whether the endotoxin is extracted with phenol-water or with trichloroacetic acid. C3H/HeJ mice do not respond (or produce GAF?) after an intravenous injection of phenol-water lipopolysaccharide, but they react normally (produce GAF?) when given a trichloroacetic acid preparation. They also behave the same as conventional animals when injected with serum from poisoned normal mice, especially when the reticuloendothelial system of the donors has been activated by prior injections of Zymosan or heat-killed tubercle bacilli. The C3H/HeJ mice have been used, therefore, as assay animals to establish that peak levels of GAF appear in donor serum about 2 h after an injection of lipopolysaccharide, and it is produced intraperitoneally in C3H/HeJ mice given a mixture of endotoxin and peritoneal exudate cells derived from responder mice. GAF elutes from Sephadex G-200 along with markers of known molecular weight in the region of 100,000 to 200,000. It is inactivated by trypsin and by heating at 75 degrees C for 1 h.

Animals↗

PubMed1990

[Exposure of Danish workers to trichloroethylene during the period 1947-1987].

Trichloroethylene, an organic solvent from the group of chlorinated hydrocarbons, has been employed throughout the greater part of this century particularly for degreasing of metals, dry cleaning and as a content in glue and lacquer. Biological monitoring of workers exposed to trichloroethylene as current health supervision has been employed in Danish factories since 1947 as the metabolite trichloroacetic acid in the urine provides an indication of the degree of exposure during the preceding week. In the present investigation, a review was undertaken of all measurements of trichloroacetic acid notified to the Danish Labour Inspection Service during the period 1947-1987 in order to obtain an impression of the historical development in the level of exposure. A total of 2,272 biological measurements distributed among 330 factories, reveal exposure of about the same level from the middle of the fifties to the middle of the seventies but with a distinct fall during the period, as the average value during the first five-year period was 82 mg/l as compared with 18 mg/l at the end of this 40-years period. These data are supplemented by case-histories from the earliest part of the period described by doctors from the Danish Labour Inspection Service.

Air Pollutants, Occupational↗

PubMed1980

Purification, immunochemical, and biologic characterization of the Schistosoma circulating M antigen.

Circulating M antigen, specific for genus Schistosoma, was previously described in serum, urine, patients' milk, and in serum and urine of animals infected by S. mansoni. The M antigen was thermostable and soluble in trichloroacetic acid. It was not hydrolyzed by protease, ribonuclease, amylase, or neuraminidase but destroyed by sodium metaperiodate. In the present study, we have purified the M ag by using trichloroacetic acid solubility, DEAE Sephadex, and immunoadsorption. The M ag showed a neutral electric charge, a m.w. heterogeneity, and was only stained by periodic acid-Schiff. The composition study revealed M ag was a glycoprotein with a polysaccharide moiety (63% of the molecules) particularly rich in galactose, fucose, glucosamine, and mannose, and with a high molecular ratio of serine and threonine. The presence of O-glycosidic linkage allowed M ag to be considered as a mucin or a mucus glycoprotein-like component. It was localized in the cell wall of the gut of adult worms.

Amino Acids↗

PubMed1976

The binding of near-ultraviolet light-induced tryptophan photoproduct(s) to DNA.

To test one possible mode of toxicity of L-tryptophan photoproduct(s) to bacterial cells, we have examined the binding of near-ultraviolet light-treated tryptophan to purified Escherichia coli DNA in vitro. The results show that co-irradiated (or pre-irradiated) [3H]tryptophan binds to purified DNA as assayed by trichloroacetic acid co-precipitation of DNA and 3H counts on cellulose filters. This was supported by co-sedimentation of DNA and 3H photoproduct(s) on CsCl gradients. Hot trichloroacetic acid extraction or enzymatic digestion of DNA prevents filter binding. The binding is most efficient when tryptophan and DNA are co-irradiated. Under these conditions, binding is more efficient with denatured rather than native DNA. From kinetic studies, the binding is DNA-dependent at constant doses of near-ultraviolet light. At a dose of 2.16 - 10(6) ergs - mm-2 we estimate that 100-150 L-[3H]tryptophan equivalents are bound per E. coli genome equivalent. The binding does not occur with another aromatic amino acid such as tyrosine.

Binding Sites↗

PubMed1992

Clearance of recombinant tissue factor pathway inhibitor (TFPI) in rabbits.

The pharmacokinetics of recombinant tissue factor pathway inhibitor (TFPI) after an intravenous bolus injection was studied in rabbits. Clearance of TFPI was followed by measurement of the radioactivity of the 125I-labelled compound in the whole plasma or the trichloroacetic acid precipitate and by quantitation of the functional TFPI activity of the unlabelled compound using a tissue factor-induced coagulation assay. When iodinated TFPI was used, the ratios of the trichloroacetic acid precipitable counts vs. that of the whole plasma was about 1 in the first 10 min after TFPI injection, but this ratio gradually decreased to less than 0.5 after 2 h. This result suggested that the iodinated TFPI in the plasma was partially degraded after prolonged circulation in the animal. When unlabelled TFPI was used, the clearance of TFPI activity from the plasma exhibited bi-exponential elimination kinetics with a rapid alpha phase half-life (t1/2 alpha) of 2.3 min, and a terminal beta phase half-life (t1/2 beta) of 79 min. The plasma clearance was 4.2 ml kg-1 min-1. The tissue distribution of intravenously administered 125I-TFPI in the rabbit was studied using whole-body autoradiography. At 3 min after dosing, significant levels of TFPI were apparent in the liver, kidney, and other highly blood perfused tissues. Significant levels of 125I-TFPI-derived radioactivity were also apparent in the liver and kidney at 30 min after intravenous administration. The localization within the liver demonstrated a mottled appearance, suggesting regions of higher uptake within the liver. In the kidney, the outer cortex consistently revealed the highest activity.

Animals↗

PubMed1997

Kinetics and metabolism of chloral hydrate in children: identification of dichloroacetate as a metabolite.

Chloral hydrate was introduced into therapeutics more than 100 years ago, and since then a number of kinetic and metabolic studies have been conducted on this drug. Trichloroethanol, its glucuronide and trichloroacetic acid have been identified as the metabolites of chloral hydrate. We now report the identification of dichloroacetate as a major product of chloral hydrate metabolism in children, in addition to trichloroethanol and trichloroacetic acid. Furthermore, pretreatment of children with chloral hydrate appears to retard the plasma clearance of dichloroacetate.

Acidosis, Lactic↗

PubMed2006

The use of Markov chain Monte Carlo uncertainty analysis to support a Public Health Goal for perchloroethylene.

The current Public Health Goal (PHG) for perchloroethylene (PCE) was derived using upper-bound estimates of fractional PCE metabolism in humans. These estimates were in part obtained from a published evaluation of the uncertainty and variability in human PCE metabolism conducted using a physiologically-based pharmacokinetic (PBPK) model in a Markov chain Monte Carlo (MCMC) analysis; however, the data used in that analysis were limited to post-exposure PCE blood and exhaled air concentrations from a single study. A more recent study [Volkel, W., Friedewald, M., Lederer, E., Pahler, A., Parker, J., Dekant, W., 1998. Biotransformation of perchloroethene: dose-dependent excretion of trichloroacetic acid, dichloroacetic acid, and N-acetyl-S-(trichlorovinyl)-l-cysteine in rats and humans after inhalation. Toxicol. Appl. Pharmacol. 153(1), 20-27.] provides data on blood concentrations of PCE and its major metabolite, trichloroacetic acid (TCA), and urinary excretion of TCA following exposure of human subjects to lower concentrations of PCE (10-40ppm) than in previous studies. In the present effort, a new MCMC analysis was performed that focused on data from this study along with two others [Fernandez, J., Guberan, E., Caperos, J., 1976. Experimental human exposures to tetrachloroethylene vapor and elimination in breath after inhalation. Am. Ind. Hyg. Assoc. J. 37, 143-150; Monster, A., Boersma, G., Steenweg, H., 1979. Kinetics of tetrachloroethylene in volunteers; influence of exposure concentration and work load. Int. Arch. Occup. Environ. Health 42, 303-309.] providing data on PCE blood concentrations and urinary excretion of TCA. To provide an accurate prediction of TCA kinetics, the PBPK model used here includes a description of the metabolism of PCE to TCA in both the liver and kidney. The resulting upper 95th percentile estimates of fraction of PCE metabolized by inhalation and oral routes were 2.1 and 5.2%, respectively, compared to 58 and 79% used in the derivation of the PHG.

Carcinogens, Environmental↗

PubMed1989

Impermeability of the ovine placenta to 35S-recombinant erythropoietin.

Controversy exists regarding the placental permeability of erythropoietin (Ep), a glycoprotein hormone that regulates red blood cell production in the fetus, newborn, and adult after tissue hypoxia. The purpose of the current study was to determine the placental permeability of biologically active 35S-labeled human recombinant erythropoietin given by bolus injection into the circulation of the fetal lamb. Specific radioactivity in fetal plasma trichloroacetic acid protein precipitate fractions increased 13-fold from preinfusion levels at 6 h (47 +/- 1.3 to 679 +/- 237 cpm/mL) and thereafter fell progressively until the study was terminated at 45 h. In contrast, maternal trichloroacetic acid protein precipitate fractions demonstrated no detectable increase in radioactivity at any time. Based on the counting precision, a rise in maternal plasma radioactivity of more than 3 cpm/mL would have been detected (i.e. 0.5% of the 582 cpm/mL rise in the fetal protein precipitate counts at six h). Similar data were obtained with simultaneously administered unlabeled human urinary Ep. We conclude that physiologically significant amounts of Ep do not cross from fetus to mother; hence, maternal Ep level functions as a separate indicator of the adequacy of tissue oxygenation in the maternal compartment.

Animals↗

PubMed1977

Antigens from human seminal plasma. Part III: studies on two new antigens from the tricholoracetic acid soluble fraction.

Two new antigens were isolated from the trichloroacetic acid soluble fraction of human seminal plasma: a polysaccharide (G-3) and a glycopeptide (G-4). Both were homogeneous, and hand sedimentation constants at infinite dilution of 2.9 X 10(-13) and 2.0 X 10(-13) resectively. Chemical and physicochemical studies suggest that both are branched molecules composed mainly of alpha-D-glucopyranosidic residues. The peptide component of G-R contains a high proporiton of the basic amino acids arginine and lysine. Since both antigens are polydispered, the low percentage of sialic acids or of some amino acids determined might have antigenic significance.

Amino Acids↗

PubMed1990

Rapid and serial determination of protein kinase C activity and of the associated [3H]PDBu binding using a 96-well microtiter plate and a cell harvester.

We propose a serial assay of both protein kinase C activity and the related [3H]phorbol 12,13-dibutyrate binding, each carried out in 96-multiwell dishes, started and stopped row by row using a multipipet. Protein kinase C activity is observed through the transfer of the gamma-phosphoryl group of radioactive ATP onto histone H1 type III-S. Enzymatic reactions are started by adding enzyme extracts and stopped by adding trichloroacetic acid. Acidic precipitates of each row are simultaneously collected on glass fiber paper using a cell harvester. The addition of bovine serum albumin and cold ATP at the end of the reaction and the addition of trichloroacetic acid in the washing fluid lead to a high recovery of protein kinase C activity and reproducible results. Measurement of [3H]phorbol 12,13-dibutyrate binding to protein kinase C was carried out in a mixed micellar solution as described elsewhere (Y. Hannun and R. M. Bell (1987) in Methods in Enzymology, Vol. 141, pp. 287-293). The quaternary complex formed from protein kinase C, phosphatidylserine, calcium, and [3H]phorbol 12,13-dibutyrate was then bound to a beaded anionic exchanger which was automatically separated from the free phorbol 12,13-dibutyrate by microfiltration using a cell harvester. The binding reaction was highly calcium- and phosphatidylserine-dependent and calcium had to be added to washing fluid for optimal recovery. Determination of protein kinase C activity and phorbol 12,13-dibutyrate binding gave results similar to those of other published methods and the signal/noise ratio was greatly increased. Using a semi-automated cell harvester, the system is partially automated and provides accurate and reproducible results.

Animals↗

PubMed1988

Binding of spermidine to a unique protein in thin-layer tobacco tissue culture.

The mechanism by which spermidine induces the appearances of floral buds in thin-layer tobacco (Nicotiana tabacum) tissue culture was studied by following the fate of the radioactive compound. [3H]Spermidine was taken up rapidly by the tissue, and after a brief lag, a portion was bound to trichloroacetic acid precipitable macromolecules. Such binding increased to a maximum on day 4 of culture, coinciding with the onset of bud differentiation, and declined thereafter until shortly before flowering. About 82% of the label in the trichloroacetic acid precipitate remained as spermidine, 14% was metabolized to putrescine, 3% to spermine, and 1% to gamma-aminobutyric acid. Spermidine was covalently bound to a protein with a molecular size of about 18 kilodaltons. Hydrolysis of this protein and analysis of the labeled entities revealed 81% spermidine, 16% putrescine, and 3% spermine. This post-translational modification of a unique protein by attachment of spermidine may be causally connected to the appearance of flower buds in thin-layer tobacco cultures.

Chromatography, High Pressure Liquid↗

PubMed1992

Salicylic acid ointment peeling of the hands and forearms. Effective nonsurgical removal of pigmented lesions and actinic damage.

A methyl salicylate-buffered, croton oil-containing 50% salicylic acid ointment peel, following pretreatment with topical tretinoin and localized 20% trichloroacetic acid, is extremely effective for removal of lentigines, pigmented keratoses, and actinically damaged skin from the dorsum of the hands and forearms. The ease of application, uniform results, decreased risk of scarring, and one-time application of this peel, in comparison with other methods used for treatment of these aging-skin changes, warrants consideration by the dermatologic surgeon.

Aged↗

PubMed1994

Potency of partially purified malleo-proteins for mallein test in the diagnosis of glanders in equines.

Malleo-proteins from synthetic broth mallein of six strains of Pseudomonas mallei were separated by trichloroacetic acid precipitation, ammonium sulfate precipitation and Ultrogel AcA 34 gel filtration chromatography. When tested comparatively with Dutch PPD mallein as standard on P. mallei-sensitized and normal horses all the strains were found to be malleinogenic, trichloroacetic acid precipitated proteins were comparable to Dutch PPD mallein in potency and innocuity whereas ammonium sulfate-precipitated proteins elicited non-specific reactions. Ultrogel AcA 34 chromatographed high molecular weight proteins (MW range > 350,000) were having equal or higher potency and without adverse reactions and low molecular weight proteins (MW range 120,000-170,000) nearly inactive. Ultrogel AcA 34 column fractionation studies revealed that mallein activity was associated with high molecular weight proteins and represented a purer sensitin than PPD mallein for the purpose of mallein test.

Animals↗

PubMed1980

The effect of histochemical methylation on the phosphate groups of nucleic acids: interpretation of the absence of nuclear basophilia.

The effect of hot methylation (hydrochloric acid-methanol)) on nuclear stainability was investigated in order to determine whether the progressive loss of basophilia is due to methylation of the diester phosphate groups of nucleic acid. DNA spots on filter paper were unchanged in their stainability towards Toluidine Blue even after methylation for 4 days, while RNA, chondroitin sulphate and hyaluronic acid lost their affinity for this dye after 4 h methylation. In formalin-fixed sections, methylation for 4 h led to a loss of nuclear basophilia. There was no concomitant increase in nuclear relative to cytoplasmic stainability with Fast Green FCF at pH 9, as judged from the use of a comparison eyepiece, evaluation of colour transparencies or by microspectrophotometry. In contrast, extraction with trichloroacetic acid prior to or after methylation led to a much improved Fast Green staining of nuclei, comparable to the staining obtainable after treatment with trichloroacetic acid alone. In conclusion, there is no evidence that hot hydrochloric acid-methanol, as used in histochemistry, methylates the diester phosphate groups of nucleic acids. The loss of nuclear basophilia can be explained as a result of the excess positive charge on the chromatin following methylation of all the protein carboxyl groups. This effect is maximal after 3-4 h treatment with acid methanol at 60 degrees C. Further methylation leads to depolymerization and extraction of DNA. RNA is depolymerized in less than 4 h.

Animals↗

PubMed2003

Analysis of intracellular nucleoside triphosphate levels in normal and tumor cell lines by high-performance liquid chromatography.

A reversed-phase ion-pair high-performance liquid chromatographic method for the direct and simultaneous determination of ribonucleoside triphosphates and their corresponding deoxyribonucleoside triphosphates in trichloroacetic acid cell extracts is presented. Using this system, high resolution of nine acid-soluble compounds, including ADP, CTP, dCTP, GTP, UTP, dGTP, dTTP, ATP and dATP in 16 normal or tumor cell lines, is obtained. The method is based on an extraction of nucleotides from cells with a solution of 6% trichloroacetic acid followed by neutralization with the addition of 5 M K(2)CO(3) just prior to HPLC analysis. Chromatographic separations were performed using a Symmetry C(18) 3.5 micrometer (150x4.6 mm) column (Waters) equipped with a NovaPak C(18) Sentry guard column with UV detection at 254 nm. The HPLC columns were kept at 27 degrees C. The mobile phase was delivered at a flow-rate of 1.0 ml/min, with the following stepwise gradient elution program: A-B (60:40) at 0 min-->(40:60) at 30 min-->(40:60) at 60 min. Solvent A contained 10 mM tetrabutylammonium hydroxide, 10 mM KH(2)PO(4) and 0.25% MeOH, and was adjusted to pH 6.9 with 1 M HCl. Solvent B consisted of 5.6 mM tetrabutylammonium hydroxide, 50 mM KH(2)PO(4) and 30% MeOH, and was neutralized to pH 7.0 with 1 M NaOH. The calibration curves (r>0.99) of the components in cell extracts were established with their aqueous standards. The average within-day precision for the nine compounds was 0.9%, and the average day-to-day precision was 5.0%. The detection limits (pmol) of the nine reagents were 1.39 (ADP), 4.32 (CTP), 15.5 (dCTP), 2.38 (GTP), 4.42 (UTP), 9.45 (dGTP), 14.6 (dTTP), 2.44 (ATP) and 11.8 (dATP). The recovery of this method for the standards ranged from 82.4 to 120.5%. The results for the detection of nucleotide pools in 16 normal and tumor cell lines were presented. In conclusion, this simplified analytical method enables the simultaneous quantitation of NTP and dNTP in cell or tissue extracts and may represent a valuable tool for the detection of minute alterations of intracellular NTP/dNTP pools induced by anticancer/antiviral drugs and diseases.

Calibration↗

PubMed1983

Glucagon degradation by human mononuclear cells.

Degradation of 125I-iodoglucagon by human mononuclear cell preparations including one containing 18%-27% monocytes, one consisting of 97% pure monocytes and one consisting of 98% lymphocytes was examined. Intact cells were incubated with 125I-iodoglucagon and degradation assessed by measuring an increase in trichloroacetic acid soluble products or in non-immunoprecipitable products. The preparation consisting of intact lymphocytes did not degrade glucagon. Glucagon was degraded by preparations containing monocytes and this degradation increased with time. No difference between monocyte degradation as measured by trichloroacetic acid or immunoprecipitation was found. Degradation by intact monocytes and by mononuclear homogenates increased sixfold from 4 degrees C to 37 degrees C. Subcellular fractionation demonstrated that the majority of the neutral glucagon degrading activity was in the 100,000 g supernatant (cytosol). Kinetic analyses gave Km values of 1.1 x 10(-5) mol/l, 7.5 x 10(-6) mol/l, and 1.2 x 10(-5) mol/l for glucagon degradation by intact mononuclear cells, homogenates, and cytosol, respectively. Inhibitor studies indicated a sulphydryl dependent enzyme was involved in glucagon degradation by both intact cells and cytosol. The monocyte appeared to be the cell responsible for degradation of glucagon by mononuclear cell preparations. The degradation of glucagon under physiological conditions by intact monocytes was mediated by a neutral proteolytic enzyme, primarily localized in the cytosol.

Cell Nucleus↗