Biomedical subjects

K C Kuo

Publications and source records attributed to K C Kuo.

57 records · Page 4Linked to original sources

PubMedDate not supplied

Urinary excretion of polyamines by patients with advanced malignancy.

Levels of putrescrine, spermidine, and spermine in urine were determined by means of a sensitive ion-exchange chromatographic method in patients with advanced solid tumor malignancies, in patients with diseases other than cancer, and in normal control subjects. Elevation above 2 SDS of the normal mean were found in varying number of patients in each tumor category. For those malignancies studied that involved more than 20 patients, the greatest incidences of increased excretion were 66% for spermine in patients with colon carcinoma and 50% for putrescine and spermidine in patients with bronchogenic carcinoma. The highest levels and greatest frequency of elevated polyamine levels were found in patients with Burkitt's lymphoma, and changes in clinical tumor status associated with treatment appeared to correlate well with polyamine levels in this disease. Abnormal amounts of polyamines were also excreted by some patients with diseases other than cancer, indicating that increased polyamine excretion is not restricted or specific to the neoplastic state. It was also found that the levels of polyamines were apparently not affected by the intake of meat or the diet eaten, and remained in a rather narrow excretion range for any one individual at different time intervals. This study was carried out as part of a program to determine and evaluate biologic materials present in body fluids that may be used to follow and evaluate response or progression of neoplastic disease in patients during treatment regimens. The results suggest that abnormal urinary polyamine levels may be characteristic of neoplastic growth for some patients with malignant disease. Further studies are necessary to determine if these compounds may be helpful in assessing disease status for patients with such solid tumor malignancies as colon and bronchogenic carcinoma although their potential as useful "biologic markers" appears less promising than originally anticipated.

Adult↗

PubMedDate not supplied

Analysis of amino acids by gas chromatography as the N-trifluoroacetyl n-butyl esters.

This presentation describes amino acid analysis with the gas chromatographic method and experimental conditions using the N-trifluoroacetyl n-butyl ester derivatives; the study we describe here was undertaken to compare gas chromatographic (GC) and ion-exchange chromatographic (IEC) analyses of amino acids in hydrolysates of 9 diverse sample types to gain insight into effects of these 2 chromatographic methods of analysis on variation in amino acid results. Our study showed that values for samples prepared by 2 separate laboratories using the same procedure were generally in good agreement when all of the hydrolysates were analyzed by a single laboratory using a single method of analysis. To compare results from gas chromatography with those from ion-exchange chromatography analyses were performed by 2 different laboratories on the same hydrolysates and on different hydrolysates prepared by the same method by both laboratories. The data demonstrate that GC and IEC can be expected to yield essentially identical results when applied to the same hydrolysate. Agreement is so close that interlaboratory differences in hydrolysate preparation of the same sample contribute as much to variation in amino acid results as does the method of analysis, a fact which should be noted in planning collaborative studies.

Acylation↗

PubMedDate not supplied

Amino acid analysis by capillary gas chromatography.

Two developments have enabled major advancements in the use of capillary gas chromatography (GC), the result being its much more widespread use in investigations on a broad range of chemical and biological problems. The 2 technological developments were the introduction of fused silica capillary columns and the development of immobilized stationary phases for capillary GC columns. Because fused silica columns with immobilized stationary phases of varying polarities are offered by numerous vendors of chromatographic equipment, they have become widely used for many analytical tasks. We conducted a study to compare the effectiveness of commercially available fused silica capillary columns with the classical ion-exchange method in the separation and quantitation of amino acids. We selected the N-trifluoroacetyl (TFA) n-butyl and the N-heptafluorobutyryl (HFB) isobutyl ester derivatives for this study because of the extensive research and application of these derivatives during the past 20 years. The amino acid content of hydrolysates of 5 materials was measured: ribonuclease, beta-lactoglobulin, lysozyme, soybean meal, and a commercial poultry feed. Single 6N HCl hydrolysates of each material were prepared to minimize sample preparation differences, and 3 independent analyses of each hydrolysate were made by each of 3 techniques: the N-TFA n-butyl and N-HFB isobutyl ester methods using capillary gas chromatography and the ion-exchange chromatographic method using a Beckman 121 M amino acid analyzer. Our results clearly demonstrate that capillary GC analysis of amino acids using fused silica bonded-phase columns provides data with good precision and in general excellent agreement with ion-exchange analyses.

Amino Acids↗