A high-performance liquid chromatography method for detecting 3-amino-1,4- dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1) and 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2) in human plasma was developed. Plasma samples of 10 normal subjects were examined. Trp-P-1 and Trp-P-2, carcinogenic tryptophan pyrolysis products, were detected in all specimens, and the concentrations of Trp-P-1 and Trp-P-2 in plasma were 68.31 +/- 24.03 fmoles/ml (mean +/- S.D., n = 10) and 18.79 +/- 4.99 fmoles/ml, respectively. Our results suggest that plasma levels of carcinogenic tryptophan pyrolysis products may be useful indicators for estimating the exposure levels of the dietary carcinogens.

Adult↗

PubMedDate not supplied

delta-aminolevulinic acid dehydratase in low level lead exposure.

No statistically significant correlation was observed between log delta-aminolevulinic acid dehydratase (ALAD) activity and blood lead levels (Pb-B) in rural or urban habitants (p greater than .5 and P greater than .1, respectively) in whom no occupational source of lead was known. However, when the values the the two groups were pooled, there was a fairly good negative correlation (r = 0.509, P less than .01). Stepwise correlation coefficient analysis indicated the existance of a threshold value of Pb-B (around 15 mug/100 ml) below which ALAD activity had nor orderly relationship with the Pb-B. In contrast with married couples, parents and their children showed a remarkably high interrelationship in values of ALAD. It is concluded that in low level lead exposure primarily genetic factors influence the activity of ALAD and, thus ALAD is useful for the evaluation of lead exposure only when the lead level is higher than the threshold.

Absorption↗

PubMedDate not supplied

Distribution of trace metals in nuclei and nucleoli of normal and regenerating rat liver with special reference to the different behavior of nickel and chromium.

The distribution of some metals in nuclei and nucleoli of normal and regenerating rat liver was determined. The contents of Ca, Zn, Cu, and Mn in nuclei were less than 3% of those in whole cells. Cr and Ni, which are known carcinogens, were present in cells in much smaller amounts than the metals above, but their contents in nuclei were more than 20% of those in cells. All of these metals were retained in nucleoli; the contents in nucleoli, per milligram of protein, were 3 (Zn) to 18 (Ni) times those in nuclei. Binding of Cr and Ni to nucleoli was more resistant than that of the other metals to treatment with nucleases. The concentrations of Ca, Zn, Cu, and Mn in nuclei and nucleoli changed synchronously with changes in the amounts of nucleic acids and protein in the corresponding fraction of the regenerating liver after partial hepatectomy. The Cr concentration showed no such synchronization.

Animals↗

PubMedDate not supplied

Determination of tri-, di-, and monobutyltin and inorganic tin in biological materials and some aspects of their metabolism in rats.

A chromatographic method to separate and determine simultaneously trace amounts of tri-, di-, and monobutyltin and inorganic tin (IV) in biological materials has been established. These compounds were eluted stepwise on a silica gel column with an organic solvent system and were sensitively determined by flameless atomic absorption spectrophotometry. The calibration curves show linearity up to 6 mumol/L. The detection limit was 1.5 ng of tin for each of the tin compounds. The reproducibility and recovery were satisfactory. Tetra- and tributyltin were also sensitively determined by the gas chromatographic application of this method. This new method was applied to the study on the metabolism of tributyltin in rats. The contents of tributyltin in the liver of rats, to which a single oral dose of tributyltin fluoride had been administered, showed a rapid decrease following an initial transient increase. The tributyltin, once transported to the liver, seemed to be rapidly dealkylated. The most significant finding was the remarkable retention of monobutyltin and inorganic tin (IV) in the brain.

Animals↗

PubMedDate not supplied

Diagnostic significance of serum angiotensin-converting enzyme activity in biochemical tests with special reference of chronic liver diseases.

To assess the degree of the differential ability of serum angiotensin-converting enzyme (ACE) activity as compared with 13 conventional biochemical tests, we studied 76 healthy subjects and 107 patients with chronic liver diseases. It was found that the mean values of serum ACE activity were significantly different between the healthy group and groups with liver disease. According to discriminant function analysis, the diagnostic accuracy reached 82.2% in 14 tests. In order to analyze the extent of contribution of each test to the entire diagnostic accuracy, we made an indicator of the relative decrease rate expressed as a percentage, which is 100-100 x (13-test diagnostic accuracy less one test/14-test diagnostic accuracy). The relative decrease rate of serum ACE activity was 11.4%, the largest in value. In conclusion, serum ACE activity may be one of the best discriminators to characterize chronic liver disease.

Adult↗