Nhu Nguyen - Academia.edu (original) (raw)
Papers by Nhu Nguyen
Mycological Research, 2005
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Arthropod Structure & Development, 2006
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Mycological Research, 2006
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American Journal of Kidney Diseases, 1997
Although hyperparathyroidism is a common feature in renal transplant recipients, the long-term co... more Although hyperparathyroidism is a common feature in renal transplant recipients, the long-term course of parathyroid hormone (PTH) secretion in these patients is not well established, and the actual contribution of PTH to posttransplant bone disease remains incompletely understood. Therefore, we studied calcium-regulating hormones and serum osteocalcin, as a marker of bone remodeling, in 82 normocalcemic renal transplant recipients with good renal function who had received a graft 6 to 73 months previously and in 82 healthy subjects matched for age and sex. In all subjects, fasting serum and 24-hour urinary samples were collected. The transplant recipients had excessive PTH secretion (serum PTH, 6.9 ± 0.5 pmol/L in recipients v 3.0 ± 0.1 pmol/L in healthy subjects; P < 0.001) and high bone turnover (osteocalcin, 16.6 ± 0.8 μg/L v 8.0 ± 0.3 μg/L; P < 0.001). (Values are mean SEM.) In addition, transplant recipients had a slightly higher ionized calcium than the healthy subjects, providing definite evidence of an inappropriate PTH secretion in renal transplant recipients. Furthermore, in subgroups of 25 recipients and 25 healthy controls matched for creatinine clearance, the results superimposed those obtained in the whole groups, suggesting that excessive PTH secretion and high bone turnover in renal transplant recipients did not merely reflect the moderately reduced renal function of some recipients. In the whole group of transplant recipients, PTH correlated positively with osteocalcin (r = 0.40; P < 0.001), suggesting that PTH contributes at least partly to posttransplant bone disease. Conversely, there was no correlation between serum PTH or osteocalcin and the delay from grafting. Therefore, our results provide no evidence for a spontaneous improvement of either persistent hyperparathyroidism or high bone turnover in normocalcemic long-term renal transplant recipients.
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Transplantation, 1995
Since the effects of cyclosporine on mineral and bone metabolism are controversial, we studied ca... more Since the effects of cyclosporine on mineral and bone metabolism are controversial, we studied calcium regulating hormones, calcium-phosphorus (Ca-P) metabolism, and bone remodeling, assessed by serum osteocalcin, in long-term renal transplant recipients (RT). Forty-seven normocalcemic patients with good renal function receiving cyclosporine (CT, n = 27) or not (NC, n = 20) were studied at baseline and after an oral Ca load. CT and NC had similar age, daily dose of steroids, GFR level, and duration of transplantation. Baseline evaluation included 24-hr urinary Ca, P, TRP, TmP/GFR, fasting serum intact PTH, 1,25-(OH)2D, 25OHD, osteocalcin, Ca, and P. Subjects of the two groups had excessive secretion of PTH, tubular P wasting, and high serum osteocalcin level, as is usual in RT. However, there was no difference between CT and NC regarding any baseline variable. Ten CT and ten NC, matched for duration of transplantation and serum PTH level, ingested 1g Ca to achieve an acute dynamic study of PTH secretion and Ca-P metabolism. In both CT and NC, this Ca load caused the same decreases in serum PTH (P &amp;amp;amp;lt; 0.001), NcAMP (P &amp;amp;amp;lt; 0.05), and urinary P (P &amp;amp;amp;lt; 0.001) and the same increases in serum and urinary Ca (P &amp;amp;amp;lt; 0.001), and in both TmP/GFR and TRP (P &amp;amp;amp;lt; 0.001). These results strongly suggest that cyclosporine treatment had no significant effect on calcium-regulating hormone secretion, P-Ca metabolism, and bone remodeling level. We therefore consider that cyclosporine is unlikely to have any prominent role in the abnormalities of bone endocrine and mineral metabolism that are common in long-term kidney recipients.
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Metabolism-clinical and Experimental, 2007
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Mycological Research, 2005
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Arthropod Structure & Development, 2006
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Mycological Research, 2006
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American Journal of Kidney Diseases, 1997
Although hyperparathyroidism is a common feature in renal transplant recipients, the long-term co... more Although hyperparathyroidism is a common feature in renal transplant recipients, the long-term course of parathyroid hormone (PTH) secretion in these patients is not well established, and the actual contribution of PTH to posttransplant bone disease remains incompletely understood. Therefore, we studied calcium-regulating hormones and serum osteocalcin, as a marker of bone remodeling, in 82 normocalcemic renal transplant recipients with good renal function who had received a graft 6 to 73 months previously and in 82 healthy subjects matched for age and sex. In all subjects, fasting serum and 24-hour urinary samples were collected. The transplant recipients had excessive PTH secretion (serum PTH, 6.9 ± 0.5 pmol/L in recipients v 3.0 ± 0.1 pmol/L in healthy subjects; P < 0.001) and high bone turnover (osteocalcin, 16.6 ± 0.8 μg/L v 8.0 ± 0.3 μg/L; P < 0.001). (Values are mean SEM.) In addition, transplant recipients had a slightly higher ionized calcium than the healthy subjects, providing definite evidence of an inappropriate PTH secretion in renal transplant recipients. Furthermore, in subgroups of 25 recipients and 25 healthy controls matched for creatinine clearance, the results superimposed those obtained in the whole groups, suggesting that excessive PTH secretion and high bone turnover in renal transplant recipients did not merely reflect the moderately reduced renal function of some recipients. In the whole group of transplant recipients, PTH correlated positively with osteocalcin (r = 0.40; P < 0.001), suggesting that PTH contributes at least partly to posttransplant bone disease. Conversely, there was no correlation between serum PTH or osteocalcin and the delay from grafting. Therefore, our results provide no evidence for a spontaneous improvement of either persistent hyperparathyroidism or high bone turnover in normocalcemic long-term renal transplant recipients.
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Transplantation, 1995
Since the effects of cyclosporine on mineral and bone metabolism are controversial, we studied ca... more Since the effects of cyclosporine on mineral and bone metabolism are controversial, we studied calcium regulating hormones, calcium-phosphorus (Ca-P) metabolism, and bone remodeling, assessed by serum osteocalcin, in long-term renal transplant recipients (RT). Forty-seven normocalcemic patients with good renal function receiving cyclosporine (CT, n = 27) or not (NC, n = 20) were studied at baseline and after an oral Ca load. CT and NC had similar age, daily dose of steroids, GFR level, and duration of transplantation. Baseline evaluation included 24-hr urinary Ca, P, TRP, TmP/GFR, fasting serum intact PTH, 1,25-(OH)2D, 25OHD, osteocalcin, Ca, and P. Subjects of the two groups had excessive secretion of PTH, tubular P wasting, and high serum osteocalcin level, as is usual in RT. However, there was no difference between CT and NC regarding any baseline variable. Ten CT and ten NC, matched for duration of transplantation and serum PTH level, ingested 1g Ca to achieve an acute dynamic study of PTH secretion and Ca-P metabolism. In both CT and NC, this Ca load caused the same decreases in serum PTH (P &amp;amp;amp;lt; 0.001), NcAMP (P &amp;amp;amp;lt; 0.05), and urinary P (P &amp;amp;amp;lt; 0.001) and the same increases in serum and urinary Ca (P &amp;amp;amp;lt; 0.001), and in both TmP/GFR and TRP (P &amp;amp;amp;lt; 0.001). These results strongly suggest that cyclosporine treatment had no significant effect on calcium-regulating hormone secretion, P-Ca metabolism, and bone remodeling level. We therefore consider that cyclosporine is unlikely to have any prominent role in the abnormalities of bone endocrine and mineral metabolism that are common in long-term kidney recipients.
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Metabolism-clinical and Experimental, 2007
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