Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0002871 (anemia)
 52,094 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The measurement of erythrocyte delta-aminolevulinic acid dehydratase (ALA-D) activity has been found to be a useful guide to lead exposure for screening purposes. The pH of the test should be well-controlled for adequate clinical interpretation. False-normal tests are rare even with iron-deficiency anemia or macrocytosis. Recent transfusion and recent bleeding or hemolysis with reticulocytosis tend to invalidate the test. ALA-D activity above 600 International Units effectively excludes significant lead exposure and eliminates the need for further testing. ALA-D activity is maximally depressed at a red cell lead concentration of 200 mug per 100 ml. When activity is moderately depressed, interpretation is difficult and the urinary excretion of lead after the administration of a chelating agent is usually required to differentiate the degree and significance of lead exposure.
 ...
PMID:Erythrocyte delta-aminolevulinic acid dehydratase activity as a measure of lead exposure. 23 93

Flounders (Pleuronectes flesus) were exposed to sublethal levels of cadmium (5, 50, and 500 micrograms of Cd2+/liter) for periods of 4 and 9 weeks, and the hematological response as well as the effect on the activity of delta-aminolevulinic acid dehydratase (ALA-D) in blood and blood-forming tissues were investigated. Significant reductions of hematocrit, hemoglobin, and red blood cell count were found in the cadmium-exposed fish. This anemic response was apparent even in flounders exposed to the lowest cadmium concentration, approximately corresponding to 1/4000 of the 96-hr LC50 value. The anemia was accompanied by a significant increase of the ALA-D activity in renal tissues. This indicates a compensatory stimulation of the introductory steps of the hemoglobin biosynthesis. However, the formation of hemoglobin does not seem to be accomplished, which might be due to a disturbed iron metabolism. The cadmium exposure also resulted in a significant increase of the number of lymphocytes, indicating an action on the immunological defense of the fish.
 ...
PMID:The effect of cadmium on the hematology and on the activity of delta-aminolevulinic acid dehydratase (ALA-D) in blood and hematopoietic tissues of the flounder, Pleuronectes flesus L. 31 13

Lead has a wide range of applications, and its production and use result in contamination of the environment, including food and drinking water. Geochemical studies indicate that the majority of lead in ecosystems originated from industrial operations, and that human lead intake has increased 100-fold above the "natural" level. Prehistoric human skeletons contain about two orders of magnitude less lead than present-day samples. Biochemical interference with heme biosynthesis can be detected as a result of current lead exposures, inhibition of aminolevulinate dehydratase and accumulation of zinc protoporphyrin in erythrocytes being the earliest effects. Anemia is uncommon except for cases of lead poisoning, but even slightly increased lead absorption results in a decrease in hemoglobin concentrations. Modern neurobehavioral test methods have disclosed increased prevalence of psychological dysfunction associated with augmented lead absorption. Biochemical and behavioral changes occur below the recommended limit for blood lead concentration of 60 micrograms/100 ml. Several diagnostic tests for lead toxicity are available. The protoporphyrin concentration in the blood seems to be the best risk indicator. The highest occupational lead exposures occur in lead smelters and storage battery plants, but several other industrial operations may result in high lead levels. As much as 1% of the working population may have a significantly increased lead absorption with possible adverse effects.
 ...
PMID:Widening perspectives of lead toxicity. A review of health effects of lead exposure in adults. 40 Sep 72

The activity of the enzyme delta-aminolevulinic acid dehydratase (ALA-D) was strongly depressed in erythrocytes, spleen and renal tissue of rainbow trouts (Salmo gairdnerii) exposed to sublethal levels of inorganic lead (10, 75 and 300 microgram Pb2+/L) for 30 days. The fish exposed to the highest lead concentration also showed an anemic response and basophilic stippling of erythrocytes. The lead exposure did not cause any alteration of the white blood cell picture. The ALA-D inhibition, the anemia and basophilic stippling seemed to persist in the lead-exposed fish even after a recovery period of seven weeks in lead-free water.
 ...
PMID:Effects of inorganic lead on delta-aminolevulinic acid dehydratase activity and hematological variables in the rainbow trout, Salmo gairdnerii. 48 10

Anemia is a constant complication of uremia. As it has been suggested that uremic toxins (middle molecules) play an important role in the mechanism of anemia, we studied the activities of three heme-synthesizing enzymes: delta-aminolevulinic acid dehydratase, porphobilinogen deaminase and ferrochelatase. In 26 patients on regular dialysis therapy, all three enzymes had significantly lower values than in normal control subjects. From our results, it can be assumed that the decreased heme biosynthesis in chronic uremic patients might be caused by a lack of erythropoietin or by uremic toxins inhibiting erythropoietin and/or heme-synthesizing enzymes.
 ...
PMID:Heme synthesis in anemia of the uremic state. 75 May 46

Blood-lead level (Pb-B), erythrocyte delta-aminolevulinic acid dehydratase (ALAD) activity, free erythrocyte porphyrin (FEP) concentration, delta-aminolevulinic acid concentration in urine (ALAU), hematocrit value, and hemoglobin concentration were compared for groups of children 10-13 years old from areas differently polluted by lead (rural area and lead smelter area). The biological responses of the children were also compared with those observed in adults similarly exposed to lead (Pb-B: 10-40 mug/100 ml). Compared with the rural children, children living less than 1 km from the smelter exhibited a significant increase of Pb-B and FEP, a significant inhibition of ALAD, and a slight positive correlation of ALAU with Pb-B; however, they showed no biological signs of anemia. In children living approximately 1.5 km from the smelter, there was still a significant increase of Pb-B and a concomitant inhibition of ALAD, but no change in FEP concentration. Comparison of the dose-response curves between Pb-B and FEP in adult males, adult females, and children indicates that the sensitivity to lead is in the order of children larger than or equal to women greater than men. Based on the FEP response, it is proposed that 25 mug Pb/100 ml blood be regarded as the maximum biologically allowable concentration of lead in blood of school-age children.
 ...
PMID:Impact of air pollution by lead on the heme biosynthetic pathway in school-age children. 99 44

In order to examine possible species differences in response to arsine exposure, multiple inhalation studies consisting of acute (1-day), subacute (14- and 28-day), and subchronic (90-day) exposures to this agent were conducted using three different species of rodents. Evaluations of hematopoietic organs and alterations in the heme biosynthetic pathway were the focus of these studies. Species used were B6C3F1 mice (exposed 1, 14, or 90 days), Fischer 344 rats (exposed 14, 28, or 90 days), and Syrian Golden hamsters (exposed 28 days). All arsine exposures were at concentrations of 0.5, 2.5, or 5.0 ppm except for 90-day studies, in which concentrations were lowered to 0.025, 0.5, or 2.5 ppm. No changes in body weight gain were observed in either sex of mice or hamsters. The only decrease in body weight gain occurred in male rats exposed to 5.0 ppm arsine for 28 days. Significant exposure-related increases in relative spleen weights occurred in both sexes of mice and rats in the 0.5 (except 14-day female rats), 2.5, and 5.0 ppm exposure groups from all studies and in hamsters in the 2.5 and 5.0 ppm exposure groups. Generally, increases in relative liver weight occurred in fewer exposure groups and were of a lesser magnitude than increases in spleen weight. Other parameters affected included decreased packed cell volumes (mice, rats, and hamsters), hematology profiles (rats), and an increase in delta-aminolevulinic acid dehydratase activity in all species. Arsenic content was measured in livers of rats after 90 days of exposure. Concentrations increased in relation to atmospheric concentrations of arsine. Histopathologic changes included increased hemosiderosis and extramedullary hematopoiesis in spleen and intracanalicular bile stasis (mice only) in liver. Additionally, bone marrow hyperplasia was observed in rats. Effects on other organs were not observed, suggesting that the hematopoietic system is the primary target for arsine. In conclusion, we have determined that the effects of arsine exposure upon mice, rats, and hamsters are similar. Most importantly, even though no effects on the hematopoietic system were observed following a single exposure to 0.5 ppm arsine which is 10 times the Threshold Limit Value (TLV) set by the American Conference of Governmental Industrial Hygienists, repeated exposure to 0.025 ppm (one-half the TLV) caused a significant anemia in rats.
 ...
PMID:Comparative toxicity of arsine gas in B6C3F1 mice, Fischer 344 rats, and Syrian golden hamsters: system organ studies and comparison of clinical indices of exposure. 236 76

Lead often affects the erythrocyte membrane. The relationship between the changes in erythrocyte membrane and the anemia caused by lead is still unclear. Initially, the effect of lead injected intraperitoneally on the electrophoretic mobility of rat erythrocytes was investigated in order to study the relationship between them. As indices of lead exposure, hemoglobin (Hb) levels, hematocrits (Ht), delta-aminolevulinic acid dehydratase (ALA-D) activities and blood lead (blood Pb) levels in the injected rats were also examined. Exposure to lead significantly decreased the mobility of rat erythrocytes. The changes in mobility seemed to be less sensitive than those in ALA-D activity, however, the decreases in mobility were simultaneous with or prior to those in Hb level and Ht. The decreases in mobility were evident to some extent below a blood Pb level of 100 micrograms/100 ml and generally present at a level of 100 micrograms/100 ml and over. In the rats exposed to lead a significant negative correlation was found between the mobilities and the logarithms of blood Pb level.
 ...
PMID:Effect of lead on electrophoretic mobility of rat erythrocytes. 375 Mar 26

Inhibition of the activity of delta-aminolevulinic acid dehydratase by heavy metals such as Cu, Cd and Au has been thought to be related to the inhibition of heme bio-synthesis in the bone marrow. This study investigates the interaction between lead and gold on porphyrin metabolism. Gold thiomalate (Au-T) was injected subcutaneously 10 times into the backs of rabbits in doses of 1, 10 and 100 mg per capita for 30 days. The latter two groups of animals showed mild anemia, but they showed neither reticulocytosis nor increase of free erythrocyte protoporphyrin (FEP). In rabbits administered lead only or lead plus gold thiomalate, however, reticulocytosis and an increase in FEP levels were observed. Therefore, the etiology of anemia may be different between rabbits administered gold thiomalate and rabbits administered lead. Rabbits injected with Au-T showed an increase in urinary coproporphyrin (CP-U) excretion. The maximum concentration of CP-U in the gold groups was about 3 times as high as that in the control group, but the increment was lower than that in the lead group. Rabbits injected with Au-T showed a higher concentration of gold in the kidneys than in other tissues. In those injected lead and Au-T together, concentration of gold in all tissues was higher than in those administered Au-T only. Proteinuria was observed in the rabbits injected Au-T. The increase in CP-U in the gold-injected rabbits was assumed to be related to the increase in gold concentration in the kidneys.
 ...
PMID:[The effect of an organic gold compound on porphyrin metabolism, with reference to interaction with lead]. 393 37

Effects of histidine deficiency on muscle carnosine and anserine levels and on activities of enzymes associated with histidine catabolism and protoporphyrin synthesis were investigated. Male Sprague-Dawley (150 g) rats were tube-fed isonitrogenous, isocaloric, defined diets containing 0%, low (0.013%) or adequate (0.45%) histidine for 8-13 days. While histidine-deficient animals maintained body weight, muscle and plasma histidine and carnosine concentrations decreased rapidly and remained low following a 3-day histidine repletion period. Hepatic histidine ammonia-lyase and histidine-pyruvate transaminase activities were decreased in histidine-deficient animals, whereas formiminotransferase activity was unchanged. Hematocrit levels and hemoglobin concentrations declined progressively during histidine depletion and the activity of erythrocyte and hepatic delta-aminolevulinic acid dehydratase also decreased relative to controls. Evidence is presented indicating that decreased histidine catabolism combined with carnosine and hemoglobin degradation can provide sufficient histidine to explain the slow onset of negative nitrogen balance associated with histidine deficiency and that impaired protoporphyrin synthesis may partially explain the anemia observed in the absence of dietary histidine.
 ...
PMID:Metabolic effects of histidine-deficient diets fed to growing rats by gastric tube. 649 66


1 2 3 Next >>