Urinary Δ-aminolevulinic Acid Research Articles

Interlaboratory Evaluation of Proficiency Testing in Urinary δ-Aminolevulinic Acid Analyses

Abstract Twenty-six European laboratories have participated in a study of various methods used for determination of δ-aminolevulinic acid in urine, to determine to what extent they give comparable results when performed by different laboratories. None of the methods as used in the program appeared to be precise and accurate enough to allow each of several laboratories to detect the small differences in urinary δ-aminolevulinic acid that would result from differences in exposure to environmental lead. Variation among results obtained by different laboratories using the same technique probably reflects differences in the practical experience each laboratory had with the various techniques, rather than intrinsic problems with the methods themselves.

Comparison of Four Methods for Determination of δ-Aminolevulinic Acid in Urine, and Evaluation of Critical Factors

Abstract Four methods—two requiring ion-exchange chromatography of urine (Mauzerall-Granick; Davis-Andelman) and two omitting the chromatographic step (Grabecki et al.; Lauwerys et al.)—for determination of urinary δ-aminolevulinic acid (I) have been compared. Experienced analysts obtained a satisfactory coefficient of variation (≤5%) for each of the four methods. Over the whole concentration range of 0 to 60 mg/liter, both chromatographic methods gave identical results. At concentrations <6 mg/liter, the automated method of Lauwerys et al. gave slightly higher results than did the chromatographic methods. At concentrations >6 mg/liter the values of I obtained with the automated method were almost identical with those yielded by the chromatographic methods, whereas with the method of Grabecki et al. one-third less was found. The results for the automated method correlated better with those for the two chromatographic methods than did those for the method of Grabecki et al. Quality control of prefilled commercially available columns (Bio-Rad) and standard solutions of I (100 µg/ml) gave results with a low variability (<10%). Ionic strength and pH of urine do not influence significantly the determination of I by the automated method, but influence determination of I by the Davis—Andelman method. With or without a preservative, I can be conserved for at least two weeks, if urine is kept at 4 °C. Tartaric acid (1 g/100 ml) or acetic acid (1 ml/100 ml) are satisfactory preservatives for urine stored in darkness at room temperature; sodium azide or thymol are less effective than acidification. During storage the concentration of I in urine decreases as pH increases (above pH 6). Only a moderate effect of natural daylight was observed.

Studies on δ-Aminolevulinic Acid Synthetase Activity in Bone Marrow in Experimental Lead Poisoned Rats

Urinary increase of δ-aminolevulinic acid and coproporphyrin as well as basophilic stippled cells in the peripheral blood are the characteristic signs of lead poisoning. The biochemical lesion of porphyrin biosynthesis in lead poisoning is the partial inhibition of δ-aminolevulinic acid dehydratase, but whether or not δ-aminolevulinic acid synthetase is induced (stimulated) or not by lead is still unknown. This paper reports that δ-aminolevulinic synthetase activity in bone marrow in lead poisoned rats was 6.8 times higher than that of normal rats. Activity was found to increase within three or four days after lead administration and in parallel with the urinary increase of δ-aminolevulinic acid.The levels of urinary δ-aminolevulinic acid and coproporphyrin in lead poisoned rats decreased markedly following the administration of mitomycin c. This phenomenon were also observed in the case of hepatic porphyria caused by diethyl-1, 4-dihydro-2, 4, 6-trimethylpyridine-3, 5-dicarboxylate poisoned rats when treated with mitomycin c.These results strongly suggest that δ-aminolevulinic acid synthetase activity is induced either directly or indirectly by lead. Excessive δ-aminolevulinic acid thus formed seems to overcome the partial blocking of δ-aminolevulinic acid dehydratase resulting in the increased formation of coproporphyrin in lead poisoning.

Normal levels of urinary δ-aminolevulinic acid measured by a new method

Normal levels of urinary δ-aminolevulinic acid measured by a new method

Effect of hematin in acute porphyric relapse.

The intravenous administration of hematin, in a patient with acute intermittent porphyria in relapse, was followed by a rapid decline of porphyrin precursors in the blood and urine, together with complete remission of the porphyric symptoms and manifestations, including abdominal pain, vomiting, constipation, tachycardia, urinary retention, and psychopathic behavior. The hematin was given for 3 days, in four doses of about 300 mg each. By serial spectroscopic observation, hematin was constantly present in the blood and available for perfusion during at least 90 hours, disappearing between 30 and 36 hours after the last unit was given. The relation of the remission to the remarkable lowering of serum and urinary δ-aminolevulinic acid and porphobilinogen and the underlying repression or inhibition, or both, of the induction of aminolevulinic acid synthetase by the hematin is discussed. Further studies to explore this question and provide information on the value of the method in aborting attacks at an early stage are needed.

Parameters indicative of absorption and biological effect in new lead exposure: a prospective study.

<b>Tola, S., Hernberg, S., Asp, S., and Nikkanen, J. (1973).</b><i>British Journal of Industrial Medicine,</i><b>30,</b> 134-141. <b>Parameters indicative of absorption and biological effect in new lead exposure: a prospective study.</b> Determinations have been made of the blood and urinary lead concentrations (Pb-B, Pb-U), haemoglobin concentrations (Hb), packed blood cell volumes (Hcr), urinary δ-aminolevulinic acid (ALA-U) and coproporphyrin concentrations (CP-U), as well as erythrocyte δ-aminolevulinic acid dehydratase activities (ALA-D), in respect of 33 workers entering occupational lead exposure for the first time in their lives. In a follow-up study lasting from one to four months samples were taken before exposure began, initially at intervals of two days and subsequently at intervals of one to two weeks. Nine control subjects were studied for Pb-B once, and for Hb, Hcr, and ALA-D weekly. The Pb-B rose and the ALA-D activity fell with no demonstrable time lag, while the latency periods of ALA-U, Pb-U, and CP-U were about two weeks. All of these laboratory tests reached a steady state during the follow-up. ALA-D showed the highest correlation to Pb-B and proved to be the most sensitive indicator of lead effect. Both CP-U and ALA-U were useful indicators of the effect of lead upon the organism, although a stepwise regression analysis, and their correlation coefficients with Pb-B, led to the conclusion that CP-U had better explaining power than ALA-U. The mean Hb and Hcr values were significantly lower at the end of the observation period than at the beginning, providing an indication that anaemia begins to develop early in the course of lead absorption.

Simple Method for Determination of Urinary δ-Aminolevulinic Acid as an Index of Lead Exposure

Abstract A simple method is described for the quantitative analysis of urinary δ-aminolevulinic acid. 2-Methyl3-carbethoxy-4-(3-propionic acid) pyrrole, produced by the condensation of δ-aminolevulinic acid with ethyl acetoacetate, is almost completely extracted from an aqueous solution with ethyl acetate without resorting to ion-exchange column chromatography. The pyrrole is determined colorimetrically by treating an aliquot of the extract with a modified Ehrlich’s reagent.

Effect of lead on blood regeneration following acute hemorrhage in dogs.

Thirty-six beagle dogs were divided into three hematologically similar groups of six males and six females each. The dogs of one group acted as controls and were fed only the basic diet. The dogs of the other two groups had lead acetate added to their diets, those of one group receiving 100 ppm of lead by weight, those of the other group, 500 ppm for 30 weeks followed by 1000 ppm for 16 weeks. By the end of 46 weeks, both lead-treated groups had accumulated burdens of lead as demonstrated by increases in blood and urine lead concentrations, increased urine δ-aminolevulinic acid excretion, and decreased red cell ALA dehydrase activity. At this time a two-step withdrawal of one-half the estimated blood volume from each dog resulted in a 30 to 40% reduction in hemoglobin concentration, red cell count, and hematocrit ratio. The recoveiy curves of the hemoglobin concentration, red cell count, and hematocrit ratio were not affected by the presence of the lead.

Urinary delta-aminolevulinic acid. Determinations among workers charging lead accumulator batteries in Lagos, Nigeria.

Urinary δ-aminolevulinic acid (ALA) levels were measured in 71 indigenous workers who charged batteries. The group consisted of 21 masters, four “free” workers, and 46 apprentices from 25 workshops in two districts of Lagos, Nigeria. Twenty adult male and female medical students of comparable age were controls. Abnormally high urinary ALA levels were found in about half the workers. The mean level was significantly higher than in controls, values being 1.49 mg/100 ml and 0.29 mg/100 ml,. respectively. The highest mean level, 3.60 mg/100 ml, occurred in masters repairing more than three batteries per month, and the highest individual reading, 7.75 mg/100 ml, was one master in this trade for 15 years. Mechanical hoods preventing inhalation of lead fumes and manufacture of low-cost cells or whole batteries were suggested as possible control measures.

The Preservation of Urine Specimens for δ-Aminolevulinic Acid Determination

Abstract The effect of light exposure and temperature on urinary δ-aminolevulinic acid recovery was studied. Addition of tartaric acid and storage of urine specimens in the dark results in excellent recovery of δ-aminolevulinic acid, even after several days at room temperature. Proper handling and storage of urine collected during surveys of lead poisoning are emphasized.

An investigation of lead absorption in an electric accumulator factory with the use of personal samplers.

<b>Williams, M. K., King, E., and Walford, Joan (1969).</b><i>Brit. J. industr. Med.,</i><b>26,</b> 202-216. <b>An investigation of lead absorption in an electric accumulator factory with the use of personal samplers.</b> Thirty-nine lead workers and controls, in stable conditions of exposure, each wore personal lead-in-air samplers daily for two weeks. During the second week samples for blood lead, urinary lead, urinary coproporphyrin, urinary δ-aminolevulinic acid (ALA), the punctate basophil count, and haemoglobin were taken daily. Duplicate estimations were made on one day. The lead exposures of men doing almost identical jobs differed by ratios of up to four to one. This could be attributed only to personal differences in working habits. The correlation coefficients and regression equations of the biochemical tests with lead-in-air and with each other were determined. The mean values and 95% confidence limits of single determinations of some of the biochemical tests corresponding to the two commonly accepted TLVs of lead-in-air (0·20 and 0·15 mg./m.³) were calculated from the regression equations. For each biochemical test the variation due to analytical error, the variation from day to day within subjects and the residual variation due to analytical error, and the residual variation about the regression on lead-in-air were calculated. Previous estimates of the latter are not known. Excessive confidence may be placed in an index of exposure due to its low coefficient of variation within subjects unless the coefficient of variation between subjects about regression is taken into account. This correction for specific gravity of estimations of lead and ALA in spot samples of urine was found to reduce slightly the residual variation between subjects about the regression on lead-in-air and to increase the correlations with lead-in-air and with the other biochemical tests, but these changes were not statistically significant. The modified method used for estimating blood lead and urinary lead is described and validated.

The Use of the Allen Correction in the Quantitative Determination of Urinary Porphobilinogen

Abstract The method of Mauzerall and Granick for the quantitative determination of urinary δ-aminolevulinic acid and porphobilinogen was found, in our hands, to give falsely elevated values for porphobilinogen. The use of the Allen correction appears to resolve this problem.

A Single Column Method for the Determination of Urinary δ-Aminolevulinic Acid

Abstract A simple method for determination of urinary δ-aminolevulinic acid is described. Its advantage over procedures now in use is in the utilization of a single ion-exchange column instead of two ion-exchange columns, with resulting saving of time, labor, and material. The method is accurate and useful in screening for lead poisoning.