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Publications (5)6.23 Total impact

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    ABSTRACT: The parathyroid-calcium (Ca(2+)-PTH) curve expresses modulation of parathyroid hormone (PTH) secretion by the parathyroid gland as a function of changing extracellular Ca(2+) concentration. Patients with hyperparathyroidism (HPT) show a rightward shift of the curve compared with controls, suggesting a reduced sensitivity of parathyroid cells to Ca(2+). Increasing the sensitivity of the parathyroid gland to extracellular Ca(2+) by manipulation of the Ca(2+)-sensing receptor (CaR) may have therapeutic potential. Calcimimetics allosterically modify CaR and render it more sensitive to extracellular Ca(2+), accounting for the simultaneous reduction of Ca(2+) and PTH seen in most patients. The Ca(2+)-PTH curve was evaluated in 10 haemodialysis patients, with baseline intact PTH levels >300 pg/ml in two haemodialysis sessions, one before and the other after (range, 9-22 weeks) cinacalcet treatment. In each session a 2-h low-dialysate Ca(2+) concentration was used to induce hypocalcaemia and maximally stimulate PTH secretion, followed immediately by a 2-h high-dialysate Ca(2+) concentration to induce hypercalcaemia and maximally inhibit PTH secretion. Significant decreases in ionized Ca(2+) and intact PTH were observed following cinacalcet treatment. Cinacalcet treatment also led to a decrease in the set point for Ca(2+) and to a leftward shift of the Ca(2+)-PTH curve. Significant differences were present in all segments of the Ca(2+)-PTH curves. The pathological rightward shift of the Ca(2+)-PTH curve seen in many HPT patients may be reversed by cinacalcet treatment.
    Nephrology Dialysis Transplantation 04/2008; 23(9):2895-901. · 3.37 Impact Factor
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    ABSTRACT: CD30 is a membrane glycoprotein that belongs to the tumor necrosis factor superfamily. It is expressed on activated T cells. After activation of CD30(+) T cells, a soluble form of CD30 (sCD30) released into the bloodstream, can be measured in the serum. The aim of our study was to investigate the time course of serum levels of sCD30 during hepatic allograft rejection. Serum levels of sCD30 were determined in 30 healthy subjects and 50 hepatic transplant recipients. These patients were divided into two groups: group I, 35 patients without rejection; and group II, 15 patients with acute rejection. Samples were collected on day 1 and 7 after transplantation and on the day of liver biopsy. The concentrations of sCD30 were similar in the rejection (40.4 +/- 16.5 U/mL) and nonrejection groups (43.0 +/- 18.2 U/mL) on postoperative day 1. We observed a significant increase in sCD30 levels in the rejection group on postoperative day 7 (76.3 +/- 61.8 U/mL vs 46.8 +/- 20.5 U/mL; P = .01). The difference increased when a diagnosis of acute rejection had been established: namely 133.0 +/- 113.5 U/mL versus 40.1 +/- 22.0 U/mL; (P = .001). These levels were also significantly higher during the entire postoperative period in all the patients, with or without rejection, than those observed in healthy controls (26.6 +/- 5.3 U/mL; P = .005). The release of circulating sCD30 is a prominent feature coinciding with the first episode of hepatic allograft rejection. So, monitoring of sCD30 levels may be useful for the early diagnosis of an acute rejection episode.
    Transplantation Proceedings 10/2007; 39(7):2295-6. · 0.95 Impact Factor
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    ABSTRACT: In successful renal transplantation, the degree of renal function recovery is usually incomplete and information is scarce about the abnormalities of mineral metabolism in long-term adult renal recipients with normal renal function. This study was designed to investigate bone mineral metabolism in patients with a long-term normal functioning kidney. Twenty-nine adult asymptomatic renal transplant (RT) recipients with stable graft function for more than 10 years and serum creatinine <2 mg/dL were studied. They were classified into two groups according to glomerular filtration rate: Group A (N = 12; nine men, three women)>70 mL/min (x: 126 +/- 55 mL/min) and Group B (N = 17; nine men, eight women) <70 mL/min (x: 56 +/- 11 mL/min). Circulating biochemical markers of bone remodelling, bone histomorphometry, and densitometry (lumbar spine and hip) were obtained to investigate bone disease in these patients. Serum PTH was slightly elevated in 10 patients (83%) in group A. Serum PTH levels were positively related to serum calcium, osteocalcin, BAP, telopeptide, OH-proline, and creatinine. There was no histologic data to support overactivity on bone in this group of patients, with only one showing high bone turnover. Mineralization was prolonged in 34% of patients. Twenty-two patients (75%) exhibited normal bone turnover. In the group with GFR>70 mL/min the prevalence of mineralization defect in the presence of normal serum levels of calcitriol suggested vitamin D resistance. Lumbar and femoral neck osteoporosis was present in 25% and 33% of patients in group A, and 23% and 53% in group B, respectively. T-score at lumbar spine was negatively correlated with months since transplantation. Patients under treatment with cyclosporine (CsA) showed increased concentrations of osteocalcin and D-pyr and higher lumbar bone mineral density (BMD), but bone histomorphometry was not influenced by CsA. Patients with long-term renal transplantation with normal renal function frequently present with slight increases in PTH, but without an effect on bone histology. CsA did not induce changes in bone histology and delayed mineralization was frequently observed.
    Kidney international. Supplement 07/2003;
  • Transplantation Proceedings 03/1998; 30(2):629-30. · 0.95 Impact Factor
  • Transplantation Proceedings 01/1998; 30(2):629-630. · 0.95 Impact Factor