Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0033687 (proteinuria)
 24,015 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Apolipoprotein D is a previously unrecognized urinary protein of unknown function which we have tested as a potential marker for kidney malfunction. This protein and alpha 1-microglobulin have been quantified by zone immunoelectrophoresis assay in urine samples from a group of eight men occupationally exposed to cadmium-containing welding fumes for many years. All these workers had highly elevated concentrations of urinary cadmium and indications of tubular proteinuria, as compared to a group of 50 apparently healthy normal men analyzed in parallel. The cadmium-exposed workers demonstrated three- and 15-fold average increases in apolipoprotein D and alpha 1-microglobulin, respectively, over normal values in urine, estimated both as excretion rates and as milligrams of protein per mmol of creatinine. All these increments were highly significantly different (P < 0.001) from the corresponding values of the reference group. Essentially the same results were obtained for each of the proteins from two independent consecutive samplings of the workers' urine. There were good linear (R = 0.70, 0.80) and logarithmic (R = 0.84, 0.81) correlations between the urinary concentrations of alpha 1-microglobulin and apolipoprotein D for both the reference and the study group. Although not as sensitive an indicator for tubular proteinuria as alpha 1-microglobulin, apolipoprotein D, being a storage-stable urinary protein, seems a valuable complement for the diagnosis of tubular malfunction.
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PMID:Apolipoprotein D and alpha 1-microglobulin in human urine: effect of cadmium exposure. 768 9

Apolipoprotein (apo) D is a glycoprotein that contains at least one free cysteine. This allows the formation of disulfide linked dimers of apoD, a phenomenon that could interfere with the study of the isoforms of apoD. Consequently, it is important to consider the effects of hetero- and homodimer formation on the molecular heterogeneity of apoD as well as on the evaluation of the specificity of antibodies to this glycoprotein. The identification of apoD in urine has provided a potential new marker of tubular proteinuria. Thus, we have studied the specificity of our polyclonal antibodies to apoD against the proteins present in normal urine, and at the same time, the existence of dimeric species of apoD linked by disulfide bonds in urine. The specimens were obtained from apparently healthy individuals and analyzed by Western blot. The results showed that apoD in urine exists as a mixture of monomers and dimers, the latter having apparent molecular weights different from those occurring in plasma. Only monomeric apoD was observed under reducing conditions, proving the monospecificity of the polyclonal apoD antibodies.
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PMID:Disulfide linked dimers of apolipoprotein D in urine. 812 62