The Cu-64 uptake test for evaluation of zinc therapy in Wilson's disease
The reduced hepatic excretion of dietary copper (Cu) by pts with Wilson's disease (WD) leads to accumulation in tissue which may result in disability or death. Penicillamine (PNC), the current treatment of choice, promotes urinary excretion causing a -Cu balance, but frequently has toxic effects. A recent therapeutic approach attempts to reduce absorption of Cu from the diet. Zinc is known to induce production of metallothionine (MT), a metal-binding protein, in gut mucosa. MT binds Cu with a high affinity, thus preventing its absorption. To assess the effects of oral zinc therapy for WD, the authors measured the absolute plasma uptake of oral Cu-64 in 8 pts. Four received elemental zinc 100-250 mg p.o. qD for at least 3 months. Four were untreated or taking PNC. Pts were hospitalized for measurements of dietary intake and total urinary and fecal excretion of Cu. Plasma volume was determined by I-131 serum albumin. Pts. then swallowed 0.5 mCi Cu-64 in 40 cc of cow's milk. Blood samples were drawn q 15 min x 90 mins with 5 additional samples over 24 hrs. Sample counts were corrected for decay and hematocrit. Total plasma uptake of Cu-64 over time was plotted as a fraction of the administered dose. Plasma uptake reached an initial peak within 90 min. in all cases and was 3.4-11.9% (mean=7.5) in pts not taking zinc but only 0.3-1.98% (mean=1.2) in those on zinc therapy (p=0.013). Preliminary data indicated a -Cu balance in zinc treated pts and a +Cu balance in those off zinc. The oral Cu-64 absorption test is far more easily performed than longterm measurements of Cu balance. It provides a rapid and simple means of assessing the efficacy of anti-absorptive therapy.
- Research Organization:
- Univ. of Michigan Medical Center, Ann Arbor, MI
- OSTI ID:
- 6929364
- Report Number(s):
- CONF-840619-; TRN: 87-008938
- Journal Information:
- J. Nucl. Med.; (United States), Vol. 25:5; Conference: 31. annual meeting of the Society of Nuclear Medicine, Los Angeles, CA, USA, 5 Jun 1984
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
COPPER
EXCRETION
COPPER 64
ORAL ADMINISTRATION
UPTAKE
DIGESTIVE SYSTEM DISEASES
THERAPY
ZINC
THERAPEUTIC USES
ANIMAL TISSUES
DEATH
IODINE 131
METALLOTHIONEIN
TOXICITY
TRACER TECHNIQUES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BETA-PLUS DECAY RADIOISOTOPES
BODY
CLEARANCE
COPPER ISOTOPES
DAYS LIVING RADIOISOTOPES
DISEASES
ELECTRON CAPTURE RADIOISOTOPES
ELEMENTS
HOURS LIVING RADIOISOTOPES
INTERMEDIATE MASS NUCLEI
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
METALLOPROTEINS
METALS
NUCLEI
ODD-EVEN NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
PROTEINS
RADIOISOTOPES
TISSUES
TRANSITION ELEMENTS
USES
550604* - Medicine- Unsealed Radionuclides in Therapy- (1980-)