Polyamide thin-layer chromatography of phosphorylated tyrosine, threonine, and serine

One-dimensional thin-layer chromatography on polyamide plates offers an easy and rapid identification of O-phosphotyrosine. The thin-layer plate is developed for 30 min in 5% propionic acid containing 0.013%-0.025% sodium dodecyl sulfate. O-Phosphotyrosine, with Rf = 0.54, can be well separated from O-phosphothreonine and O-phosphoserine, which comigrate at Rf = 0.72.

An effect of predilution on potency assays of factor VIII concentrates

The effect of prediluent on potency assays for Factor VIII concentrates was evaluated systematically using a well defined one stage Factor VIII assay. It was demonstrated that potency values were higher when Factor VIII deficient plasma was used as the prediluent compared to identical assays performed when barbital buffered saline solution was used as prediluent. Prediluent is therefore an important variable to evaluate in establishing the validity of any proposed Factor VIII potency assay. Since the goal of Factor VIII potency measurement is to predict therapeutic effect, the use of Factor VIII deficient plasma is the more satisfactory alternative where a difference exists, since this diluent approximates best the conditions which occur when a Factor VIII concentrate is injected into the bloodstream of a patient with hemophilia A.

Microbial mutagenicity of 3- and 4-ring polycyclic aromatic sulfur heterocycles

The stable isomers of 3- and 4-ring polycyclic aromatic sulfur heterocycles were tested for mutagenicity in the Ames standard plate incorporation test and a liquid pre-incubation modification of the Ames test. Of the 4 three-ring compounds tested, only naphtho[1,2-b]thiophene was mutagenic. Of the four-ring compounds, 7 of 13 were mutagenic in the standard Ames or pre-incubation Ames test. The highest activity for the 4-ring compounds was observed for phenanthrol[3,4-b]thiophene, a compound of approximately the same mutagenic potency in the Ames test as benzo[a]pyrene. The other active 4-ring compounds were of considerable less mutagenic potency than phenanthrol[3,4-b]thiophene. Mutagenicity for two of the 4-ring aromatic thiophenes could only be detected in the liquid pre-incubation Ames test. Salmonella typhimurium TA100 was the most sensitive strain to mutagenesis by these compounds, followed by TA98. All mutagenesis was indirect, requiring metabolic activation.

Identification of volatile organic compounds produced by fluorescent pseudomonads on chicken breast muscle

Four different fluorescent pseudomonads were isolated from spoiled, uncooked chicken breasts and were grown in pure culture on initially sterile chicken breast muscle at 2 to 6 degrees C for 14 days. The volatile compounds produced by each culture were concentrated on a porous polymer precolumn and separated and identified by high-resolution gas chromatography-mass spectrometry.

Capillary column gas chromatography of environmental polycyclic aromatic compounds

The methodologies are described for isolating clean fractions of polycyclic aromatic compounds from diverse environmental samples such as air particulate matter, sediments, and fish tissue. The common step in all procedures is the separation of the polycyclic aromatic compound fraction into well-defined chemical classes by adsorption chromatography on an alumina column. These procedures greatly facilitate the detailed characterization of the polycyclic aromatic hydrocarbons, sulfur heterocycles, and nitrogen heterocycles by capillary column gas chromatography.

Effects of acupuncture on serum cortisol level and dopamine beta-hydroxylase activity in normal Chinese

Serum cortisol levels were determined in 40 normal Chinese and dopamine beta-hydroxylase activities were measured in 22 normal subjects before and after acupuncture treatment. All subjects were studied twice with an interval of one week or more. In the self-control study, the subjects were needled at 5 non-acupuncture loci. In the experimental study, they were needled at the following 5 traditional acupuncture loci--right side GB-20, both sides EH-6, and both sides St-36. Blood samples were withdrawn before acupuncture and 15 and 45 min. after acupuncture. No change of serum dopamine beta-hydroxylase activity was observed. Serum cortisol levels increased significantly after needling on the traditional acupuncture loci. After acupuncture for 15 and 45 min., the cortisol increase was 28 and 50%, respectively, as compared to the self-control studies. The beneficial effect of acupuncture in the treatment of functional disorders, therefore, may be mediated by cortisol or other hormones and neurohormones.

On-column propylation method for measuring plasma valproate concentration by gas chromatography

A gas-chromatographic method is described for measuring plasma valproate concentrations. This method incorporates double-solvent extraction of the plasma sample and on-column propylation of valproic acid and 2-propylhexanoic acid, used as the internal standard. The identity of the propyl ester derivatives of these compounds was confirmed by gas chromatography-mass spectrometry. The accuracy and simplicity of the method make it suitable for routine laboratory use. The assay is sufficiently rapid that a plasma sample can be analyzed in duplicate within 30 min.

Dimethyl and monomethyl sulfate: presence in coal fly ash and airborne particulate matter

Dimethyl sulfate and its hydrolysis product monomethyl sulfate have been found at concentrations as high as 830 parts per million in fly ash and in airborne particulate matter from coal combustion processes. This discovery poses a new environmental problem because of the mutagenic and carcinogenic properties of these compounds.

Autosomal-dominant inheritance of distal arthrogryposis

We report on a 32-year-old Italian man, his 5-year-old daughter, and his 3 1/2-year-old son, all of whom had congenital joint contractures. Each has severe ulnar deviation of fingers and soft-tissue contractures of both hands; and each had bilateral clubfeet at birth. The father is short in stature, as are the children, who also have delayed carpal ossification. The findings in this family suggest autosomal-dominant inheritance of the condition. The clinical features are consistent with the condition currently referred to as "distal" arthrogryposis.

Trisomy in the distal end of the long arm of chromosome 3. A condition clinically similar to the Cornelia de Lange syndrome

A patient had a trisomy for the distal portion of the third chromosome. The major clinical features were failure to thrive, profound mental retardation, dysmorphic head shape, a short nose, anteverted nares, long eyelashes, synophrys, characteristic mouth, and short stature. The similarities between the clinical picture and the Cornelia de Lange syndrome are very striking.

High-resolution gas chromatographic profiles of volatile organic compounds produced by microorganisms at refrigerated temperatures

Three different strains of bacteria isolated from spoiled, uncooked chicken were grown in pure culture on Trypticase soy agar supplemented with yeast extract. The volatile organic compounds produced by each culture were concentrated on a porous polymer precolumn and analyzed by high-resolution gas chromatographic mass spectrometry. Twenty different compounds were identified. Both qualitative and quantitative differences in the chromatographic profiles from each culture were found.

Autosomal recessive sensorineural hearing impairment, dizziness, and hypodontia

A previously undescribed syndrome with profound sensorineural hearing loss since early infancy, episodes of dizziness, and hypodontia developed in a brother and sister. The presence of two unaffected children and unaffected parents suggests autosomal recessive inheritance.

Source identification of urban airborne polycyclic aromatic hydrocarbons by gas chromatographic mass spectrometry and high resolution mass spectrometry

Polycyclic aromatic hydrocarbons formed during the combustion of three common fuels (coal, wood and kerosene) were separated and identified by capillary-column gas chromatographic mass spectrometry and were compared to airborne polycyclic aromatic hydrocarbons from Indianapolis, a high coal consuming area, and Boston, a low coal consuming area. High resolution mass spectral data were utilized in the construction of alkyl homolog plots for the comparison of alkyl distribution within each sample.

Effects of Medicare on hospital use: a disease-specific study

This paper presents results of a study to determine 1) the effects of Medicare on the patients of hospital use in specific disease groups, and 2) the sensitivity of length of stay and proportions of admission in specific disease groups to "short-run" changes in hospital occupancy rates. The analysis indicates that Medicare did increase utilization of hospital services by patients 65 and over through increases in both admissions and average length of stay. The largest increases occurred in the lower risk disease categories, although it is pointed out that this result does not necessarily imply a misallocation of hospital resources. The results also indicate significant differences among different socioeconomic groups and a much greater initial impact on the 75 and over age group than on the 65-74 age group.

Human tryptophan transfer ribonucleic acid synthetase. Composition, function of thiol groups, and structure of thiol peptides

Human tryptophanyl-tRNA synthetase resembles its counterpart in Escherichia coli in quaternary structure (alpha2), but differs in molecular weight, amino acid composition, the number of thiol groups, and the relationship of the thiol groups to enzyme activity. Nevertheless, one of the thiol groups resides in a heptapeptide sequence homologous to a heptapeptide sequence containing a thiol group in the E. coli enzyme. Each subunit of the enzyme has 6 half-cystine residues, and four thiol groups are readily titrated with 5,5'-dithiobis(2-nitrobenzoic acid). Titration of these four thiol groups inactivates the enzyme, and the inactivation is partially reversible by reduction with dithiothreitol. One thiol group reacts rapidly unless L-tryptophan, ATP, and Mg2+ are present together.

Tryptophanyl transfer ribonucleic acid synthetase of Escherichia coli. Character of required thiol group and structure of thiol peptides

Native tryptophanyl-tRNA synthetase purified from Escherichia coli B has on each identical subunit a single thiol group which rapidly forms a mixed disulfide with a thionitrobenzoate moiety of 5,5'-dithiobis(2-nitrobenzoic acid). The reaction and the concomitant inactivation of the enzyme are both reversible by reductive removal of the thionitrobenzoate with dithiothreitol. Iodoacetamide and N-ethylmaleimide also react with the thiol group required for enzyme activity, but iodoacetic acid inactivates the enzyme through another mechanism. Three or 4 half-cystine residues/subunit were detected by amino acid analysis and by titration of the denatured enzyme with 5,5'-dithiobis(2-nitrobenzoic acid); no disulfide bonds were detected by borohydride reduction. Cleavage of the subunit (molecular weight 37,000) with 2-nitro-5-thiocyanobenzoic acid gave fragments of molecular weights 32,000, 27,000, and 9,500. Five carboxymethylated peptides were isolated from the trypsin products of the denatured enzyme after treatment with iodo[14C]lacetate. Three of these peptides represented unique sequences surrounding thiol groups in the enzyme. One cysteine-containing nonapeptide has a heptapeptide sequence homologous to a heptapeptide sequence in a cysteine containing decapeptide from the tryptophanyl-tRNA synthetase of human placenta. The nonapeptide appears to bear the thiol group required for enzyme activity.

High-resolution gas chromatography/mass spectrometric analysis of tobacco and marijuana sterols

Components of the sterol fraction of tobacco and marijauna were resolved as trimethylsilyl derivatives by gas chromatography with glass capillary columns. Ten phytosterols in tobacco and five in marijuana were identified by comparisons of their retention with authentic compounds on three different stationary phases and through mass-spectral data.

A possible chemical basis for the higher mutagenicity of marijuana smoke as compared to tobacco smoke

The results of comparative anslyses of polynuclear aromatic hydrocarbons in marijuana and tobacco smoke indicate a considerably higher content of potential carcinogens in the former. A model experiment involving delta9-tetrahydrocannabinol suggests that the pyrolysis products of cannabinoids are major contributors to the polynuclear aromatic hydrocarbons.

Amino acid activation in mammalian brain. Purification and characterization of tryptophan-activating enzyme from buffalo brain

l-Tryptophan-activating enzyme [l-tryptophan-tRNA ligase (AMP), EC 6.1.1.2] of water-buffalo brain was purified to near homogeneity by heat and pH treatments, ammonium sulphate fractionation, column chromatography on DEAE-cellulose, hydroxyapatite and Amberlite CG-50, and gel filtration on Sephadex G-200. The purified enzyme catalyses tryptophanyl-tRNA formation with yeast tRNA, but not with Escherichia coli tRNA. The enzyme exhibits multiple peaks of activity in Sephadex gel filtration with molecular weights corresponding to 155000, 105000 and 50000. However, only one peak of activity with molecular weight of 155000 can be detected when the enzyme is subjected to gel filtration at high concentration. Disc gel electrophoresis in the presence of sodium dodecyl sulphate reveals a single band with molecular weight of 55000. The activity of the enzyme is concentration dependent. Different K(m) and V(max.) values are obtained at different enzyme concentrations. These data suggest that this enzyme may exist in different quaternary structures, each with its own kinetic constants. The enzyme activity is inhibited by p-chloromercuribenzoate, and is not protected by the presence of the substrates, l-tryptophan, Mg(2+), ATP, in any combination.