Determination of epsilon-aminocaproic acid in serum by reversed-phase chromatography with fluorescence detection.
Explore the source record for details and available documents.
Amino Acids↗
Biomedical subjects
G J Schmidt
Publications and source records attributed to G J Schmidt.
More sensitive high-pressure liquid-chromatographic determiantion of theophylline in serum.
We present procedures for determining theophylline in 50 mul of serum. The drug is extracted into a small volume of solvent that contains an internal standard, 8-chlorotheophylline. The extract is Analyzed by isocratic reversedphase chromatography, with measurement of eluted theophylline at 273 nm. Day-to-day reproducibility within 5% is attainable for the concentration range 5--20 mg/liter. Other xanthines and related metabolites do not interfere. Sensitivity is 1 mg/liter. The correlation coefficient, when results by a spectrophotometric procedure were compared, was 0.989. Amobarbital, secobarbital, phenobarbital, and diphenylhydantoin do not interfere. Total analysis time for a single sample is 15 min.
Chromatography, High Pressure Liquid↗
Hemoglobin Cranston, an unstable variant having an elongated beta chain due to nonhomologous crossover between two normal beta chain genes.
An asymptomatic woman was found to have a compensated hemolytic state due to an unstable hemoglobin variant, comprising 35% of the total. Peptide maps of tryptic digests of the abnormal beta chain were identical to those of beta A except that tryptic peptide 15 (Tyr-His-COOH) was absent and a new peptide was detected, containing equivalent amounts of Ser, Ile, Thr, and Lys. Its sequence was determined by manual Edman degradation. An additional hydrophobic peptide isolated by counter-current distribution contained: Asx, Ser, Ala, Tyr, 2 Phe, and 3 Leu. Its sequence was determined on an automatic solid phase sequencer. Digestion with carboxypeptidase A confirmed the C-terminal sequence. Hemoglobin Cranston has an elongated beta chain with the following structure: (see article). This variant is the first "adult" human hemoglobin known to contain isoleucine. It is likely that hemoglobin Cranston arose because of a nonhomologous crossover of two normal beta chain genes, probably during meiosis, with the insertion of two nucleotides (AG) at position 144, resulting in a frame shift. Hemoglobin Cranston provides new information on the structure of the beta chain gene as well as an explanation of both the structure and genetic basis of hemoglobin Tak, the only other elongated beta chain variant that has been described.
Amino Acid Sequence↗
The acetylation of hemoglobin by aspirin. In vitro and in vivo.
The chemical modification of hemoglobin by aspirin (ASA) has been studied, both in intact human red cells and in purified hemoglobin solutions. After incubation of red cells with 20 mM [acetyl-1minus14C]ASA, incorporation of radioactivity into hemoglobin was observed in agreement with the results of Klotz and Tam (1973. Proc. Natl. Acad. Sci. U. S. A. 70: 1313-1315). In contrast, no labeling of hemoglobin was seen when [carbosyl-14-C]ASA was used. These results indicate that ASA acetylates hemoglobin. The acetylated hemoglobin was readily separated from unmodified hemoglobin by both gel electrofocusing and by column chromatography. Quantitation of the extent of acetylation by densitometric scanning of gels agreed very well with estimates obtained from radioactivity measurements. Hemolysates prepared from red cells incubated with ASA showed normal oxygen affinity and heme-heme interaction. Purified acetylated hemoglobin had a slightly increased oxygen affinity and decreased heme-heme interaction. There was no difference in the rate of acetylation of oxy- and deoxyhemoglobin. ASA acetylated column-purified hemoglobin A more readily than hemoglobin in crude hemolysate, but less rapidly than purified human serum albumin. The rate of acetylation of hemoglobulin increased with pH up to approximately pH 8,5. Structural studies were done on hemoglobin incubated with 2.0 mM and 20 mM [acetyl-1-14-C]ASA. Alpha- and beta-chains were acetylated almost equally. Tryptic digests of purified acetylated subunits were fingerprinted on cellulose thin layer plates and autoradiographed. Both alpha- and beta-chains showed a number of radioactive spots that were either ninhydrin negative or weakly ninhydrin positive. These results indicate that hemoglobin is acetylated at a number of sites, probably at the epislon-amino group of lysine residues. To determine whether ASA acetylates hemoglobin in vivo, hemolysates of 14 patients on long-term high-dose ASA therapy were analyzed by gel electrofocusing and compared to specimens of individuals not receiving ASA. The ASA-treated group had a twofold increase in a minor hemoglobin component having an isoelectric point lower than that of hemoglobin A, and indistinguishable from the minoe component which appears when hemoglobin is incubated with ASA in vitro.
Acetylation↗
Custom design.
The most successful software programs are those that are developed through close interaction between programmers and industry professionals. The Cape Girardeau Surgical Clinic found that custom-tailored programs resulted in proper billing and handling of its patient population.
Group Practice↗