Biosynthesis of 5-aminolevulinic acid and heme from 4,5-dioxovalerate in the rat.

We previously demonstrated an alternate pathway for the biosynthesis of 5-aminolevulinic acid (ALA) in bovine liver mitochondria and of tetrapyrroles in suspensions of rat hepatocytes (1980. J. Biol. Chem. 255: 3742; 1981. Proc. Natl. Acad. Sci. USA. 78: 5335). This pathway involves a transamination reaction that incorporates the intact 5-carbon skeleton of 4,5-dioxovaleric acid (DOVA) into ALA. We investigated this alternate pathway in vivo by the intraperitoneal injection of DOVA into rats. Incorporation of DOVA and [5-14C]DOVA into urinary ALA and hepatic and erythroid heme was quantified and compared with the incorporation of [4-14C]ALA and [2-14C]glycine into heme. Within 3 h of injection of 175 mumol of DOVA, urinary ALA excretion increased 2.4-fold over controls. After injection of [5-14C]DOVA, 0.11% of the radioactivity was recovered as urinary ALA, which quantitatively accounted for the 2.4-fold increase in ALA excretion. After the injection 175 mumol of [5-14C]DOVA, 0.14% of the radioactivity was recovered after 3 h as hepatic heme. The injection of 1.75 mmol of [2-14C]glycine or 175 mumol of [4-14C]ALA resulted in recovery of 0.2 and 3.4%, respectively, of the radioactivity as hepatic heme after 3 h. These doses of radiolabeled DOVA, glycine, and ALA were injected into rats with phenylhydrazine-induced anemia. Recovery of radioactivity after 3 h as splenic (erythroid) heme was 0.35% for DOVA, 0.072% for glycine, and 0.25% for ALA. These studies establish that the intact 5-carbon skeleton of DOVA can be incorporated into ALA and heme in vivo.

Erythropoietic porphyria of the fox squirrel Sciurus niger.

Uroporphyrin I is found in high concentration in the bones, teeth, blood, soft tissues, and urine of the fox squirrel, Sciurus niger. The concentration of uroporphyrin in fox squirrel spleen is much higher than in liver, kidney or bone marrow, probably because of accumulation from phagocytosed red cells. Bleeding causes a marked increase in the uroporphyrin concentration of red cells and spleen, and a 3-8-fold increase in uroporphyrin excretion. Urinary excretion of delta-aminolevulinic acid and porphobilinogen is not greater in fox squirrels than in nonporphyric gray squirrels. Sciurus carolinensis, used as controls. In all these characteristics, as well as in the previously demonstrated deficiency of the enzyme uroporphyrinogen III cosynthetase in red cells, the physiological porphyria of fox squirrels resembles congenital erythropoietic porphyria, a hereditary disease of man and cattle. For squirrels differ in showing no evidence of cutaneous photosensitivity or hemolytic anemia. Uroporphyrinogen III cosynthetase activity is present in fox squirrel bone marrow at 1/10 its concentration in gray squirrel marrow. The fox squirrel enzyme is much more unstable than the gray squirrel enzyme, which provides a possible explanation for its low activity and for the overproduction of uroporphyrin I. It is unlikely that the deficiency of cosynthetase is due to its inactivation by excessive amounts of uroporphyrinogen I synthetase, because activity of the latter enzyme is the same in blood from fox and gray squirrels.Fox squirrel porphyria provides a convenient model for studies of pathogenesis of human congenital erythropoietic porphyria.

Urinary excretion of porphyrins is increased in patients with HIV-1 infection.

Urine concentrations of total porphyrins and of porphyrin precursors, delta-aminolaevulinic acid and porphobilinogen, were analysed in the first-morning urine samples of 36 people with established HIV-1 infection. For comparison, we also analysed the urine samples of 26 healthy HIV-seronegative people. In patients with HIV-1 infection concentrations of total porphyrins were found to be significantly higher than in healthy controls. Furthermore, there was a close correlation between concentrations of total porphyrins and porphobilinogen and urine neopterin concentrations in patients. Our data indicate an association between chronic immune activation and altered porphyrin metabolism. The data may provide a rationale for the observation of acute porphyria in patients with HIV-1 infection.

Haem biosynthesis studied in patients with rheumatoid arthritis.

In a study of the urinary excretion of haem precursors in patients with rheumatoid arthritis, iron-deficiency anaemia, and in healthy controls, certain differences were found. In iron-deficiency anaemia the excretion of both porphobilinogen and delta-aminolevulinic acid was increased, whereas in patients with rheumatoid arthritis only the porphobilinogen excretion was increased.A further study on the erythrocyte activity of delta-aminolevulinic acid dehydrase showed a higher activity in the erythrocytes from patients with rheumatoid arthritis compared with healthy controls.

Comparative effects of glycerol and dextrose on porphyrin precursor excretion in acute intermittent porphyria.

The effects of dietary manipulations on excretion of the porphyrin precursors, delta-aminolevulinic acid (ALA), and porphobilinogen (PBG) were studied in eight patients with acute intermittent porphyria. Three diet periods of 9-17 days comprised each study. In each patient, a "baseline" protein, fat, and carbohydrate intake was kept constant throughout. In addition, during the first diet period each patient received 150 g dextrose; during the second, this was replaced by an isocaloric amount of neutral fat; and during the third, the fat was replaced by 150 g glycerol. In each of the patients, three comparisons of the effect of diet on both ALA and PBG excretion were made: (1) 300 g carbohydrate versus 150 g carbohydrate (dextrose versus fat), (2) 150 g carbohydrate + 150 g glycerol versus 150 g carbohydrate (glycerol versus fat), and (3) 300 g carbohydrate versus 150 g carbohydrate + 150 g glycerol (dextrose versus glycerol). For each of these three diet comparisons, there are sixteen individual comparisons possible for the effect of diet on porphyrin precursor excretion, eight for ALA and eight for PBG. Thus, the mean values for ALA and PBG excretions during each of the diet periods are statistically compared internally within each individual patient. Increasing carbohydrate intake from 150 g to 300 g by isocaloric substitution of dextrose for fat produced a significant (p less than 0.05) decline in eight of the sixteen comparisons of ALA and PBG excretion. Addition of 150 g glycerol by isocaloric substitution for fat caused a significant (p less than 0.05) decline in nine of the sixteen possible comparisons. In the sixteen comparisons of isocaloric dextrose and isocaloric glycerol-substituted diets, dextrose produced significantly (p less than 0.05) lower porphyrin precursor excretion in four cases and glycerol produced significantly (p less than 0.05) lower values in five. One patient showed no significant change on any of the diets. Of the four patients having symptoms believed referrable to porphyria during the study, three reported an improvement in symptoms during the high glycerol intake. The effects of dietary perturbations on porphyrin precursor excretion in acute intermittent porphyria are variable, but glycerol appears to be capable of decreasing the excretions and may prove useful in treating some of these patients.

Calcium levulinate medication. A pitfall in the diagnosis of organic acidurias.

Five children, who received calcium levulinate (calcium 4-oxopentanoate) intravenously in pharmacological doses excreted in the following 24-h period both 4-oxopentanoic acid (3.5--11.0 mg/24 h) and 4-hydroxypentanoic acid (4.5--10.4 mg/24 h). Attention is drawn to the fact that in gas chromatographic-mass spectrometric systems these compounds closely resemble the two acids found in children with beta-ketothiolase deficiency.

Urinary excretion of succinylacetone and delta-aminolevulinic acid in patients with hereditary tyrosinemia.

Succinylacetone was excreted in the urine from four patients, with hereditary tyrosinemia i.e., two patients with the severe infantile type with fatal outcome and two patients with less severe juvenile form. In the urine from two patients with neonatal transient tyrosinemia and from normal individuals succinylacetone was not detectable. The urinary excretion of delta-aminolevulinic acid was also increased in all patients with hereditary tyrosinemia compared to patients with neonatal transient tyrosinemia and to normal individuals. The results presented support the hypothesis of a deficiency of fumarylacetoacetase in hereditary tyrosinemia. Furthermore an analytical method for the quantitative determination of succinylacetone in urine using GC-MS is described.

Species difference of urinary excretion of delta-aminolevulinic acid and coproporphyrin in mice and rats exposed to lead.

The urinary excretion of delta-aminolevulinic acid (ALA) was first investigated in mice exposed to lead in the drinking water (500 ppm) for 30 days, and the results were compared with those obtained from rats exposed to lead under the same exposure condition. The result indicated that the level of urinary ALA excretion in lead-exposed mice was much higher than that in lead-exposed rats. This finding suggests a species difference between mice and rats with regard to sensitivity to lead. On the other hand, urinary coproporphyrin (CP) was also determined in rats and mice exposed to lead. The result obtained indicated that the increasing level of urinary CP excretion was higher in rats than in mice, contrary to expectation. The reason for the discrepancy between urinary excretion of ALA and that of CP in rats and mice exposed to lead is, however, unknown.

Urinary excretion of 5-hydroxyindoleacetic acid, delta-aminolevulinic acid and coproporphyrin isomers in rats and men exposed to lead.

The urinary excretion of 5-hydroxyindoleacetic acid (5-HIAA), delta-aminolevulinic acid (ALA) and coproporphyrin (CP) isomers (I and III) was investigated in rats and workers exposed to lead. Urinary excretion of 5-HIAA, which is the major metabolite of serotonin, was not influenced by the lead exposure. However, a significant increase in urinary ALA and CP was found in rats and workers exposed to lead. In particular, the urinary excretion of CP-III was markedly increased compared to that of CP-I in rats and workers exposed to lead.

A chronobiological study of delta-amino levulinic acid urinary excretion.

Determination of urinary delta-amino levulinic acid (ALA) is now systematically used in occupational health to detect an excessive exposure to lead in professionally exposed workers. However, to determine whether circadian changes of the urinary excretion of ALA alter the significance of the test, we quantified the ALA levels in the urine of 19 healthy young adults. Urine samples were taken every 3 hr between 0700 and 2300 hr and ALA levels were determined by a spectrocolorimetric method. The data indicated that the 24-hr mean ALA level was: 1.81 mg/g creatinine. The peak values (2.24 +/- 0.24) were obtained between 1400 and 1700 hr whereas the lowest ALA levels were found between 2200 and 0300 hr. Cosinor analysis revealed a significant circadian rhythm while no significant difference could be found according to sex. Possible explanations of our findings are discussed.

[Aminolcevulinic acid excretion in women before and after delivery and in their newborn infants (authors transl)]. / Uber die Delta-Aminolävulinsäure-Ausscheidung von Müttern und deren Neugeborenen vor und nach der Geburt

A report is given on the excretion of variation of-aminolaevulinic acid (ALA) as an index of the lead load in pregnant women at term and at one and also at four weeks after delivery in both mothers and the newborn infants. The mean values in women were 7.2 + 3.7 before delivery 9.0 + 4.1 one week and 4.1mg ALA/1 urine four weeks after delivery; mean values of 5.2 + 3.2 one week after birth and 2.2 + 1.0 mg ALA/1 urine four weeks after birth were recorded in the newborn infants, according to the method of Davis and Andelman. Two groups were set up: mothers coming from the rural environs of Vienna and mothers living in the centre of the city. The ALA excretion was 14% lower in the former group (20% four weeks post partum) as compared with the mothers living in the city. When these data are considered against a threshold value of 10 ALA/1 urine (set up by the "Hauptverband der Berufsgenossenschafen", Bonn, West Germany, using the same method) the mean value of 9.0mg ALA/1 urine (with individual values of up to 17.4mg ALA/1 urine) in mothers one week after delivery already seems extremely serious.

Multicollinearity may lead to artificial interaction: an example from a cross sectional study of biomarkers.

Collinearity is the situation which arises in multiple regression when some or all of the explanatory variables are so highly correlated with one another that it becomes very difficult, if not impossible, to disentangle their influences and obtain a reasonably precise estimate of their effects. Suppressor variable is one of the extreme situations of collinearity that one variable can substantially increase the multiple correlation when combined with a variable that is only modestly correlated with the response variable. In this study, we describe the process by which we disentangled and discovered multicollinearity and its consequences, namely artificial interaction, using the data from cross-sectional quantification of several biomarkers. We showed how the collinearity between one biomarker (blood lead level) and another (urinary trans, trans-muconic acid) and their interaction (blood lead level* urinary trans, trans-muconic acid) can lead to the observed artificial interaction on the third biomarker (urinary 5-aminolevulinic acid).

Urinary delta-aminolevulinic acid as a biological indicator throughout penicillamine therapy in lead intoxication.

A group of 121 patients with occupational lead exposure was studied. Saturnism was confirmed in 42 of them. Patients were given D-penicillamine in doses of 0.75 and 1.5 g/day. Urinary delta-aminolevulinic acid was selected as a toxicity biological indicator; its concentrations were quantified daily during therapy. Urinary delta-aminolevulinic acid is considered a good biological indicator throughout penicillamine therapy and also in the detection of lead intoxication. Likewise, the chelating test is considered an excellent method to confirm the diagnosis of lead poisoning.

Lead exposure patterns and parameters for monitoring lead absorption among workers in Singapore.

A study was carried out among 1414 workers in 14 industries in Singapore to determine the extent of their exposure to lead and their lead absorption. High-level exposure situations found included secondary lead smelting, followed by mixing of lead salt stabilizers and lead storage battery manufacture. Other exposure situations included those relating to lead welding, print shop, wire splicing, leaded paint manufacture, fire-fighting and soldering. Early cases of lead absorption could not be detected by clinical signs alone. Other parameters such as blood lead and delta-aminolaevulinic acid dehydratase had to be used. There was good correlation between a rise in blood lead and a fall in delta-aminolaevulinic acid dehydratase levels.

[Circadian rhythms in urinary coproporphyrin and delta-aminolevulinic acid]. / Ritmi circadiani nell'escrezione urinaria delle coproporfirine e dell'acido delta-aminolevulinico.

The circadian rythm concerning the excretion of urinary metabolites ALA and CP was investigated. More ALA and CP are excreted in the urine during the day than the night. This phenomenon is more evident with CP. The sampling of urine for biochemical control of saturnism is discussed and the sample collected after 24 h was chosen.

Blood lead and urinary delta aminolevolonic acid (U-ALA) in the diagnosis of lead toxicosis of dogs.

A comparative evaluation of the usefulness of blood lead and urinary delta aminolevolonic acid estimations in the diagnosis of canine lead poisoning was made in 2 dogs which were given increasing quantities of lead by mouth for extended periods. In both lead administered dogs the blood lead levels remained elevated throughout the experimental period of 18 weeks. This contrasted with the results of U-ALA determinations in which elevated levels were detected only infrequently and at erratic intervals lacking relationship to lead exposure.

[Continuous-flow determination of delta-aminolevulinic acid in urine (author's transl)]. / Dosage de l'acide delta-aminolévulinique urinaire. Automatisation en flux continu.

The automatic determination of urinary ALA using a continuous flow methodology, is described. The amplification of the measured signal, with an adjusted range expander, allows to reduce the sample volume and to decrease drastically the effects of interfering substances. The results are compared with the reference method of Davis and Andelman [11].

[Urinary delta-aminolevulinic acid levels in dairy cows during lead loading from feed rations under normal conditions of rearing in the Western Slovakia Region]. / Koncentrácie kyseliny delta-aminolevulovej v moci dojníc pri zátazi olovom z krmnych dávok v bezných podmienkach chovov Západoslovenského kraja.

The concentration of delta-amino levulinic acid (ALA) was determined in the urine of clinically healthy cows of 14 herds in the West-Slovakian region. The content of lead was determined at the same time in the components of feed rations. The ALA concentration values were converted to values per uniform specific weight of urine and per gram of secreted creatinine to match literary sources where the ALA concentration is given in these two quantities. The approximate intake of lead by the animal bodies in milligrams per head/day and per kg of live weight was calculated from lead content in feed rations. The average ALA concentration in the urine of dairy cows was 42.7 +/- 20.2 mu mol per 1 of urine (36.8 +/- 18.7 mu mol per g of creatinine), the average lead intake from feed being 0.157 mg per kg of live weight. The ALA concentrations in urine refer to animals given normal feeds with no lead contamination and as such can be considered as physiological values. Statistically significant correlations were recorded between ALA concentrations per litre of urine at the uniform specific weight of 1030 g per litre and the values converted per gram of secreted creatinine (r = 0.789). The upper biological tolerance limit of ALA concentration in urine (105.0 mu mol per litre) was determined by mathematico-statistical methods. Values above this limit could be indicative of an increased lead stress of the cows' bodies.

[Determination of delta aminolevulinic acid in the urine of cows in acute mass lead poisoning]. / Vyuzitie stanovenia kyseliny delta amínolevulovej v moci kráv pri akútnej hromadnej otrave olovom.

The concentration of delta aminolevulinic acid (ALA) in the urine of dead heifers (n = 3), diseased cows (n = 13) and clinically healthy cows (n = 29) was determined in the course of acute mass intoxication with lead. At the same time, the content of lead was determined in kidney, liver, in rumen contents of dead heifers and in the beet pulp fed to the animals. The ALA concentrations were converted to values per uniform specific weight of urine and per gram of creatinine secreted with urine. As found, the determination of ALA concentration per gram of creatinine is diagnostically insignificant in the case of lead poisoning. The average ALA values in the urine of the dead and clinically diseased cows (221.0, 119.9 and 72.3 mumol per litre) markedly differed from the average values of ALA concentrations in the urine of the clinically healthy animals (41.2, 32.8 and 25.6 mumol per litre). Owing to the wide variability of the determined ALA concentration in urine it appeared useful in cases of suspicion of lead poisoning of cattle to determine ALA concentration in the urine of the group of clinically diseased animals and in the group of clinically healthy animals in order to compare ALA secretion with urine in the two groups. A 2.9-fold average increase of ALA in the urine of clinically diseased animals, compared with the ALA values in the urine of clinically healthy animals, already testifies to lead intoxication.

[Excretion of porphyrin and porphyrin precursor during ethylene oxide inhalation].

The effect of chronic inhalation of ethylene oxide on urinary coproporphyrin and delta-aminolevulinic acid were studied. When Wistar male rats were exposed to 500 ppm ethylene oxide three times a week, daily urine volume was increased by 200-300% from the first week to the fifth week of the experimental period. After exposure, daily coproporphyrin excretion and urinary coproporphyrin per mg of creatinine increased by 250% and 141%, respectively. On the other hand, daily excretion of delta-aminolevulinic acid in urine tended to increase but did not increase significantly by creatinine-correction. We think this is the first report of ethylene oxide induced experimental porphyria.