No change of hyperleptinemia despite a decrease in insulin concentration in patients with chronic renal failure on a supplemented very low protein diet

Chronic renal failure (CRF) is often accompanied by hyperleptinemia caused by deficient renal metabolism of leptin and possibly increased leptin production, which in turn may result from the hyperinsulinemia and increased proinflammatory cytokine levels in patients with CRF. The hyperinsulinemia and insulin resistance observed in patients with CRF improve on supplemented very low protein diets (SVLPDs). The goal of our study is to determine whether the correction of hyperinsulinemia and insulin resistance in patients with CRF by SVLPDs is accompanied by improvement in hyperleptinemia. Thirteen patients were studied before and 1 year after following SVLPDs providing 0.3 g/kg/d of protein, supplemented with amino acids and ketoanalogues. After 1 year, patients showed markedly less hyperinsulinemia (7.4 +/- 1.6 versus 13.8 +/- 2 microU/mL at the start of diet; P: = 0.05) and insulin resistance, whereas serum leptin levels remained unchanged (16.1 +/- 4.7 versus 19.1 +/- 7.4 ng/mL at start of the study; P: = not significant). The initial correlation between serum leptin level and percentage of body fat persisted during follow-up. No correlation was found between insulin and leptin levels or between the variation of these two parameters during the study. Our study shows that the correction of hyperinsulinemia and insulin resistance in patients with CRF by SVLPDs is not accompanied by improvement in hyperleptinemia, which consequently does not appear to result from changes in carbohydrate metabolism.

Analytical and prospective evaluation of urinary cytokeratin 19 fragment in bladder cancer

PURPOSE

We evaluated CYFRA 21-1, an immunoradiometric assay, developed to detect soluble cytokaratin 19 fragment, for its diagnostic performance in bladder transitional cell carcinoma as well as its analytical performance.

MATERIALS AND METHODS

We assessed CYFRA 21-1 in the serum and urine of 182 patients, including 66 with bladder transitional cell carcinoma (group 1), 66 with another urological pathology (group 2) and 50 free of urothelial disease (group 3). The power of urinary CYFRA as a diagnostic test for bladder transitional cell carcinoma was evaluated by receiver operating characteristics curve analysis. Analytical performance was assessed by determining intra-assay and interassay precision, and accuracy by dilution testing and recovery of supplemented analyte.

RESULTS

Mean urinary CYFRA plus or minus standard deviation was 154.39+/-49.00, 22.6+/-8.9 and 2.40+/-0.14 ng./ml. in groups 1 to 3, respectively (significantly different). Receiver operating characteristics curve analysis revealed optimal 96.9% sensitivity and 67.2% specificity for a threshold value of 4 ng./ml. Analytical determination showed that intra-assay and interassay precision provides a satisfactory coefficient of variation. The assay for accuracy had acceptable recovery in diluted samples as well as in those with supplemented analyte.

CONCLUSIONS

The urinary immunoradiometric CYFRA 21-1 assay performs well analytically. Urinary CYFRA 21-1 is a useful marker for diagnosing transitional cell carcinoma and provides sensitivity in low grade disease.

Review of 10 years of the clinical use of brain natriuretic peptide in cardiology

Ten years ago brain natriuretic peptide (BNP), the second compound of a family of polypeptide hormones named natriuretic peptides was identified. This peptide has great pathophysiologic importance as a stress-induced cardiac hormone secreted from ventricles, and it rises in several cardiac diseases. It promotes natriuresis and diuresis, acts as a vasodilator, and antagonizes the vasoconstrictor effects of the renin-angiotensin-aldosterone system. The measurement of this peptide in blood by immunoassay has shown promise over the past decade in clinical diagnosis and prognosis. Because heart failure is a major health problem worldwide, BNP is proposed as a biochemical marker that might provide a useful screening test to select patients for further cardiac investigations. Such a hormone assay is inexpensive and available. The implications of BNP in diagnosis, prognosis, and therapy will be reviewed.