An Analysis of 248 Initial Mobilization Tests Performed on an Ambulatory Basis

“…An amount of lead mobilized in excess of 600 mg (or >1 pg Pb/mg EDTA in a child) is considered proof of increased lead burden (115). Unfortunately, the EDTA challenge test is not a consistent predictor of body lead burden (118). Furthermore, the test is fraught with technical difficulties and has a potential to increase lead toxicity.…”

Section: Methods To Assess Increased Body Lead Burdenmentioning

confidence: 99%

Renal effects of environmental and occupational lead exposure.

Loghman‐Adham

1997

Environ Health Perspect

252

122

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Environmental and industrial lead exposures continue to pose major public health problems in children and in adults. Acute exposure to high concentrations of lead can result in proximal tubular damage with characteristic histologic features and manifested by glycosuria and aminoaciduria. Chronic occupational exposure to lead, or consumption of illicit alcohol adulterated with lead, has also been linked to a high incidence of renal dysfunction, which is characterized by glomerular and tubulointerstitial changes resulting in chronic renal failure, hypertension, hyperuricemia, and gout. A high incidence of nephropathy was reported during the early part of this century from Queensland, Australia, in persons with a history of childhood lead poisoning. No such sequela has been found in studies of three cohorts of lead-poisoned children from the United States. Studies in individuals with low-level lead exposure have shown a correlation between blood lead levels and serum creatinine or creatinine clearance. Chronic low-level exposure to lead is also associated with increased urinary excretion of low molecular weight proteins and lysosomal enzymes. The relationship between renal dysfunction detected by these sensitive tests and the future development of chronic renal disease remains uncertain. Epidemiologic studies have shown an association between blood lead levels and blood pressure, and hypertension is a cardinal feature of lead nephropathy. Evidence for increased body lead burden is a prerequisite for the diagnosis of lead nephropathy. Blood lead levels are a poor indicator of body lead burden and reflect recent exposure. The EDTA lead mobilization test has been used extensively in the past to assess body lead burden. It is now replaced by the less invasive in vivo X-ray fluorescence for determination of bone lead content.Imagesp928-aFigure 1.Figure 2.Figure 2.Figure 3.

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“…In particular, it requires parenteral administration of a drug and a timed urine collection of at least 6 and preferably 8 hr (11,12). An unreplicated study found transient, but not sustained, elevations in brain Pb content after single dose injections of CaNa2EDTA given to leaded rats (13).…”

Section: Historically Erythrocyte Protoporphyrin (Ep) Measurements Wmentioning

confidence: 99%

Children with Moderately Elevated Blood Lead Levels: A Role for Other Diagnostic Tests?

Markowitz¹,

Clemente²,

Rosen³

1997

Environmental Health Perspectives

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JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.. The National Institute of Environmental Health Sciences (NIEHS) and Brogan & Partners are collaborating with JSTOR to digitize, preserve and extend access to Environmental Health Perspectives.In this study we examined potential limitations of relying exclusively on blood lead (BPb) levels to evaluate children with moderately elevated BPb levels (1.21-2.12 pamol/l, or 25-44 lig/dl). We tested the following hypotheses: 1) such children without elevated erythrocyte protoporphyrin (EP) levels (>0.62 pmol/l or >35 pg/dl) are unlikely to respond to a chelating agent with a brisk urinary Pb diuresis; 2) those with elevated EP levels, but low hematologic indices consistent with iron deficiency, are also unlikely to respond to a chelating agent with a robust urinary Pb diuresis; and 3) those with elevated EP levels and iron sufficiency are more likely to respond to a chelating agent. To test these hypotheses, we performed retrospective analyses of the relationships between EP concentrations, hematologic indices, and urinary Pb excretion ratios (uPbr) in moderately Pb-poisoned children undergoing the CaNa2EDTA lead mobilization test (Pb-MT). Data from 122 children were available. Urinary Pb excretion was limited in children with an EP <0.62 plmol/l (<35 pg/dl); only 5% (1/21) of Pb-MTs were positive (uPbr >0.6). In children with an EP >0.62 limol/l, low hematologic indices, such as a mean corpuscular hemoglobin (MCH) <23 pg, were associated with relatively little Pb excretion (0/14 positive Pb-MTs). In contrast, 32% (28/87) of Pb-MTs were positive in children with an EP >0.62 pmol/l and iron sufficiency (p<0.01 by chi-square comparison between groups with EP >0.62 plmol/l and either MCH <23 pg or MCH >23 pg). We conclude that only a minority of moderately Pbpoisoned children will demonstrate enhanced urinary Pb excretion in response to chelation therapy. Some of the predicted nonresponders can be readily identified by adding the EP and complete blood count to the panel of tests performed. Key words: blood lead levels, chelation, erythrocyte protoporphyrin, iron deficiency, lead diagnosis, lead mobilization test, lead poisoning, urine lead.Learn how to responsibly manage the by-products of health care as part of your commitment to a healthy community.Dedicated to the memory of Karen Wetterhahn, a medical researcher who died 10 months after being exposed to one drop of dimethyl mercury.For information, call 800-639-3188 or visit our web site: http://uvmce.uvm.edu:443/profprog.htm

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An Analysis of 248 Initial Mobilization Tests Performed on an Ambulatory Basis

Cited by 11 publications

References 7 publications

Predicting the Outcome of the CaNa 2 EDTA Challenge Test in Children with Moderately Elevated Blood Lead Levels

Predicting the Outcome of the CaNa 2 EDTA Challenge Test in Children with Moderately Elevated Blood Lead Levels

Renal effects of environmental and occupational lead exposure.

Children with Moderately Elevated Blood Lead Levels: A Role for Other Diagnostic Tests?

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