Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027497 (nausea)
 23,468 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Unexpected differences in clinical and biochemical findings in two brothers occupationally exposed to the same source of lead for dissimilar lengths of time are presented. Only the brother with the shorter period of lead exposure was anemic and afflicted by nausea, vomiting, abdominal colic and arthralgia. His urinary PBG output yielded the high orders of magnitude found in acute intermittent porphyria in relapse. Prior to administration of a single dose of EDTA (1 g of the calcium disodium salt given intravenously in 325 mL 0.15 mol/L NaCl), his blood lead levels averaged 3.6 mumol/L. The amount of chelatable lead retrieved from his urine, 31 mumol/day, was more than twice that found in his asymptomatic counterpart who was exposed to lead for 13 months and whose pre-EDTA blood lead levels averaged 4.0 mumol/L. Not only the activity of delta-aminolaevulinic acid dehydratase, but also that of uroporphyrinogen I synthetase, was markedly inhibited by lead in red cells of both brothers. These activities were restored to normal levels in vitro by addition to the assay system of zinc and dithiothreitol. This ruled out a coexisting genetic deficiency of either enzyme. The anemia of the symptomatic brother with the shorter period of lead exposure was alleviated by folic acid, 15 mg/day. The differences in findings between the two brothers point to differential susceptibility to lead and illustrate the extent to which symptomatic lead poisoning may mimic biochemical and clinical features of the acute porphyrias.
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PMID:Occupational lead exposure: studies in two brothers showing differential susceptibility to lead. 401 20

The acute hepatic porphyrias include four disorders: acute intermittent porphyria [AIP], hereditary coproporphyria [HCP], variegate porphyria [VP], and the rare porphyria due to severe deficiency of ALA dehydratase [ADP]. In the USA, AIP is the most severe and most often symptomatic. AIP, HCP, and VP are due to autosomal dominant genetic abnormalities, in which missense, nonsense, or other mutations of genes of normal hepatic heme biosynthesis, in concert with other environmental, nutritional, hormonal and genetic factors, may lead to a critical deficiency of heme, the end-product of the pathway, in a small but critical 'regulatory pool' within hepatocytes. This deficiency leads to de-repression of the first and normally rate-controlling enzyme of the heme synthetic pathway, delta- or 5-aminolevulinic acid [ALA] synthase-1, and thus to marked up-regulation of this key enzyme and to marked hepatic overproduction of ALA. In addition, except for ADP, there is marked overproduction as well of porphobilinogen [PBG], the intermediate immediately downstream of ALA in the synthetic chain, and, especially in HCP and VP, also porphyrinogens and porphyrins farther down the pathway. The major clinical features of the acute porphyrias are attacks of severe neuropathic-type pain. Pain is felt first and foremost in the abdomen but may also occur in the back, chest, and extremities. Attacks are more common in women than in men [ratio of about 4:1], often accompanied by nausea, vomiting, constipation, tachycardia, and arterial hypertension. Hyponatremia may also occur. Some patients also describe chronic symptoms of pain, anxiety, insomnia, and others.
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PMID:Pathogenesis and clinical features of the acute hepatic porphyrias (AHPs). 3098 16