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Publications (28)61.27 Total impact

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    ABSTRACT: To evaluate the compassionate use of cinacalcet for the management of secondary hyperparathyroidism in patients who are not on dialysis. Patients with stage 4-5 chronic kidney disease (CKD) who were not on dialysis, had an intact parathyroid hormone (iPTH) level greater than 300 pg/mL, and had not responded satisfactorily to treatment with phosphate binders and vitamin D were prospectively studied. Patients received 6 months of compassionate treatment with cinacalcet, which was initiated at a dose of 30 mg/day orally and flexibly dosed thereafter based on iPTH levels. Twenty-six patients with a mean age±standard deviation (SD) of 58.8±16.1 years were enrolled in the study and included in the statistical analysis. The mean percentage change in iPTH levels from baseline after 6 months of treatment was -67.9±17.0%, with 92.3% (95% confidence interval (CI), 75.9-97.9) of patients showing an iPTH level within the limits recommended by Kidney Disease Outcomes Quality Initiative (K/DOQI) guidelines. The mean serum calcium concentrations had decreased significantly at the end of the study (-8.0±6.9%), while the mean serum phosphorus concentration had significantly increased (+8.3±17.0%). Our results suggest that cinacalcet may be a useful alternative for the treatment of secondary hyperparathyroidism in pre-dialysis patients who are unresponsive to other treatments. The hypocalcemia and hyperphosphatemia reported in previous studies may not occur if a moderate dose of calcimimetics is used in patients with marginal glomerular filtration rates, especially if combined with vitamin D analogues and calcium-based phosphate binders.
    Nephrology 01/2012; 17(1):26-31. · 1.69 Impact Factor
  • Fuel and Energy Abstracts 01/2010; 107(4):138-138.
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    ABSTRACT: Cardiac arrhythmias are a frequent event in chronic hemodialysis patients. The aim of this study was to evaluate the efficacy and safety of acetate-free hemofiltration with potassium-profiled dialysate (AFB-K) dialysis compared with constant potassium acetate-free biofiltration (AFB). Twelve patients (mean age 79 years) affected by cardiac arrhythmias or at a high risk for arrhythmia (advanced age, hypertension, left ventricular hypertrophy, heart valve disease, coronary artery disease, diabetes, paroxysmal atrial fibrillation) participated in a single-center, sequential cohort study. All were treated with hemodialysis 3 times per week, using constant potassium AFB for the first 3 weeks, followed by an AFB-K dialysate for the subsequent 3 weeks. The hemofilter, duration of dialysis, and electrolyte concentration were the same in both treatments. Both AFB-K and constant potassium AFB dialytic techniques were safe and well tolerated. The results of biochemical tests were similar, except for serum potassium levels after 2 hr of dialysis, which were significantly higher in the AFB-K group (4.0 mmol/L) than in the constant potassium AFB group (3.6 mmol/L) (p<0.001). All cardiac variables improved during AFB-K dialysis. There was a significant reduction of postdialysis QT intervals corrected for heart rate in the AFB-K group (448.8 ms) compared with the constant potassium AFB group (456.8 ms) (p=0.039). The severity and mean number of ventricular extasystoles also decreased (163.5 vs. 444.5/24 hr). Potassium profiling during hemodialysis treatment may be beneficial for patients with arrhythmias or at those risk of arrhythmias, particularly those with predialysis hyperkalemia.
    Hemodialysis International 01/2008; 12(1):108-13. · 1.44 Impact Factor
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    ABSTRACT: Advances in bag connection technology have reduced the incidence of peritonitis in CAPD patients but there is little information on the effect of the new peritoneal dialysis fluids. We studied the incidence of CAPD peritonitis for about 3 years in 100 incident patients--50 patients dialysed with lactate-buffered solution, pH 5.5 and containing glucose degradation products (GDP) (lactate group), and 50 patients with pure bicarbonate-buffered solution, pH 7.4 and low GDP (bicarbonate group). Patients in both groups were similar in age, sex, length of time on CAPD, connection technology and handling of dialysis. In the lactate group, 74 episodes of peritonitis were recorded compared with 43 in the bicarbonate group, i.e. one episode per 21 patient-months with the lactate dialysis fluid and one episode per 36 patient-months with the bicarbonate dialysis fluid (OR 0.58, 95% CI 0.37-0.91, P = 0.017). A total of 3369 exchanges per episode of peritonitis were recorded for bicarbonate compared with 2004 exchanges per episode of peritonitis in the lactate group. The majority of organisms isolated in both groups were Gram-positive bacteria, with a predominance of the oropharyngeal and cutaneous endogenous flora. Three episodes of fungal peritonitis occurred in the lactate group and none in the bicarbonate group. Our results suggest that the pure bicarbonate-buffered peritoneal dialysis fluid appears to reduce the frequency of peritonitis in CAPD patients possibly in relation to greater biocompatibility and maintenance of peritoneal membrane structural integrity. Similar results can probably relate to all low-GDP solutions.
    Nephrology Dialysis Transplantation 07/2007; 22(6):1703-8. · 3.37 Impact Factor
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    ABSTRACT: Online hemodiafiltration (online HDF) is a new hemodialysis technique combining convection and diffusion and thus also enabling the purification of large molecules. As yet, only a small number of clinical experiences have been published about the effectiveness and safety of online HDF. We present a prospective and observational study conducted on 31 patients treated with online HDF in our center in the last 4 years. The purpose of the study is to compare the evolution of the following aspects before and after starting online HDF: dose of dialysis, purification of medium-sized/large molecules, inflammation, nutrition, Ca-P metabolism, anemia, and intradialytic complications. Online HDF increased Kt/V to 31.0% (p > 0.001) and reduced postdialysis beta(2)-M to 66.4% (p > 0.001). The rest of the parameters analyzed did not vary significantly. During online HDF, episodes of symptomatic hypotension fell by 45% in relation to conventional hemodialysis, and no relevant complication occurred. Online HDF is very useful in patients in whom we need to increase replacement therapy, such as patients with a large body surface, those in whom we suspect a residual syndrome or those who have been receiving dialysis for a long time and for whom we wish to prevent amyloidosis. Online HDF is safe and better tolerated than conventional hemodialysis.
    Hemodialysis International 01/2006; 10 Suppl 1:S28-32. · 1.44 Impact Factor
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    ABSTRACT: Secondary hyperparathyrodism (SH) is an early manifestation of chronic renal failure (CRF), which has serious complications. Moreover, treating SH is not a risk-free process. Once in its advanced state, it is extremely difficult to reverse and therefore it is critical an early intervention and prevention. An excess of phosphorus and a deficit of calcium and calcitriol are key factors in the evolution of SH. Despite the fact that plasma phosphorus levels remain normal until an extremely advanced stage of CRF, and even apparent hyperphosphatemia in mild CRF, it has been shown that restricting dietary levels of protein and phosphorus impedes the progression of SH. A decrease of protein in the diet also decreases the amount of calcium, thus the calcium levels must be supplemented in order to prevent their deficit. In addition to that slightly diminished levels of calcitriol can be observed in the early stages of CRF, thus it is logical to provide this hormone. However, administering calcitriol may induce hypercalcemia and hyperphosphatemia, which in turn risks the onset of cardiovascular calcifications and complications. Therefore, the calcitriol dosage should be small and then adjusted according to the degree of SH. Neither the PTH levels nor alterations in the phospho-calcium metabolism follow a linear increase appropriate to the decrease in renal function, therefore we propose a treatment strategy which adapts to the different degrees of renal failure.
    Nefrologia: publicacion oficial de la Sociedad Espanola Nefrologia 02/2003; 23 Suppl 2:57-63. · 1.27 Impact Factor
  • Saudi journal of kidney diseases and transplantation: an official publication of the Saudi Center for Organ Transplantation, Saudi Arabia 01/2003; 14(2):202-4.
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    ABSTRACT: Valuation of doxazosin, system formulation modified, in the hypertension in the hemodialysis population. Arterial Hypertension (AHT) has been studied in 77 patients (p) subjected to hemodialysis (HD). Mean age (mag) was 61 years (y), range 84y-25y; 66% were males. The underlying etiology was glomerular in 19%, tubulo-interstitial in 18%, congenital in 18%, vascular in 19% and diabetic in 26%. Doxazosin (system formulation modified, single daily dose (4 mg), treatment follow-up was completed in 16 patients subjected to HD for 24 weeks (wk). It is concluded that AHT is of great importance in HD, and can be adequately controlled with the new antihypertensive drugs. In this context, doxazosin affords excellent therapeutic control, efficiency and good pharmacological tolerance.
    Anales de medicina interna (Madrid, Spain: 1984) 05/2002; 19(4):176-8.
  • Anales de medicina interna (Madrid, Spain: 1984) 01/2002; 19(4).
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    ABSTRACT: BsmI polymorphism of the vitamin D receptor gene has been linked to hyperparathyroidism severity and calcitriol levels. The aim of this study was to analyze the response to a single bolus of calcitriol in hemodialysis patients with the BB and bb genotype. Twenty homozygous BsmI hemodialysis patients (9 BB and 11 bb). Hyperparathyroidism was assessed comparing basal PTH levels, and in 17 patients, also measuring the inhibition with hypercalcemia. Patients were given a bolus of calcitriol and PTH in absolute terms and in percentages relative to the baseline values at 24, 48 and 72 hours after the bolus were measured. All biochemical parameters were compared between genotypes with univariant ANOVA and additionally, PTH relative values were compared with general factorial analysis of variance, adjusting for calcium and phosphorus. Means were also compared within each genotype between consecutive determinations with non-parametric Wilcoxon analysis, using each patient as his/her own control. The response to calcitriol was also assessed by the area under the curve for each patient and was subsequently compared between genotypes. There were no differences on hyperparathyroidism severity between the groups. The BB genotype showed a better response than bb to calcitriol 72 hours after the bolus (percentage relative to basal PTH value: BB: 63%, bb: 88.6%, p = 0.03; BB vs bb with univariant ANOVA). When general factorial analysis of variance was applied, adjusting for serum calcium and phosphorus, genotype showed a significant influence on the response to calcitriol at 72 hours (p = 0.04). When each patient was used as his/her own control, the BB genotype showed a significant decrease in PTH levels at 48 and 72 hours (p = 0.00 baseline vs 48 h, and p = 0.01 baseline vs 72h) whereas the bb did not. BsmI polymorphism of the VDR gene induces differences on the response to a single bolus of calcitriol independently of calcium and phosphorus.
    Clinical nephrology 09/2001; 56(2):111-6. · 1.29 Impact Factor
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    ABSTRACT: BsmI vitamin D receptor (VDR) gene polymorphism has been associated with the severity of hyperparathyroidism in patients on hemodialysis. The aim of this study was to analyze the influence of this polymorphism on parathyroid function and serum calcitriol levels in patients with different degrees of chronic renal failure (CRF) before dialysis. A total of 248 CRF patients, divided into three groups according to creatinine clearance (CCr; mild CRF group> 60 to </=85 ml/min, N = 54; moderate CRF group> 35 to </=60 ml/min, N = 113; severe CRF group> 10 to </=35 ml/min, N = 81), had their serum intact parathyroid hormone (iPTH) and calcitriol levels measured and BsmI genotype frequencies estimated by polymerase chain reaction (PCR) analysis. Diabetics, those on treatment with steroids, vitamin D or derivatives, and phosphorus binding agents were excluded. All those with serum calcium levels of <2.25 mmol/liter or> 2.5 mmol/liter and serum phosphorus levels of> 1.6 mmol/liter or who needed phosphorus binding agents were excluded. The statistical analysis was done with the general factorial analysis of variance entering first PTH and then calcitriol as the dependent variable; the genotype (BB, Bb and bb), sex and CCr group were defined as factors; and covariables included serum calcium, serum phosphorus, 1/creatinine versus time slope, PTH when calcitriol was the dependent variable, and calcitriol when PTH was the dependent variable. When serum PTH levels were entered as the dependent variable, serum calcium, CCr group, and the interaction of genotype with the CCr group were found to be significant factors (P = 0.025, P <0.001 and P = 0.039, respectively). When serum calcitriol levels were entered as the dependent variable, genotype, the interaction of genotype with CCr, the CCr group, and the 1/creatine versus time slope were found to be significant (P = 0.027, P = 0.028, P <0.001 and P = 0.044, respectively). The marginal means of PTH, adjusted with the general factorial analysis of variance across the three groups were: (a) mild CRF group, BB 5.3 pmol/liter (CI 0 to 13.8), Bb 5.5 pmol/liter (CI 2 to 9), bb 5.4 pmol/liter (CI 0.6 to 10.2); (b) moderate CRF group, BB 6.2 pmol/liter (CI 1.5 to 10.9), Bb 7.8 pmol/liter (CI 5.3 to 10.3), bb 7.5 pmol/liter (CI 4.8 to 10.1); (c) severe CRF group, BB 9.3 pmol/liter (CI 4.2 to 14.3), Bb 17.1 pmol/liter (CI 13.9 to 20.2), bb 21.9 pmol/liter (CI 18.7 to 25.2). The marginal means of calcitriol adjusted with the general factorial analysis of variance across the three groups were: (a) mild CRF group, BB 47 pg/ml (CI 37 to 57), Bb 40.9 pg/ml (CI 37 to 44.8), bb 32.6 pg/ml (CI 26.8 to 38. 4); (b) moderate CRF group, BB 24.1 pg/ml (CI 18.3 to 29.8), Bb 26.6 pg/ml (CI 23.5 to 29.7), bb 25.3 pg/ml (CI 22 to 28.6); (c) severe CRF group, BB 27.4 pg/ml (CI 21.3 to 33.5), Bb 19.4 pg/ml (CI 15.5 to 23.2), bb 20.4 pg/ml (CI 16.1 to 24.7). The progression of hyperparathyroidism is slower in predialysis patients with BB genotypes than in the other genotypes. Also, calcitriol levels are less reduced in the BB genotype, which may act to lessen the severity of secondary hyperparathyroidism.
    Kidney International 11/1999; 56(4):1349-53. · 8.52 Impact Factor
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    ABSTRACT: Angiotensin converting enzyme inhibitors (ACEIs) have been shown to be effective in the treatment of dialysis patients with high blood pressure, however, they also have been associated with anaphylactoid reactions at the start of dialysis, when they have been used concomitantly with AN69 membranes. A multicenter, open six-month study was designed to test the tolerability and efficacy of losartan as antihypertensive in patients under hemodialysis (HD), with particular emphasis on the appearance of anaphylactoid reactions. HD patients with systolic blood pressure (SBP) levels > or = 140 and/or diastolic blood pressure (DBP) > or = 90 mm Hg, previously nontreated, treated but uncontrolled, or treated with a poor tolerability, were included. The study performed three controls: baseline, at month 3, and at study completion. DBP and SBP levels were measured on the six HD sessions previous to the three visits in addition to biochemical and hematology measurements. Four hundred and six patients were included. The mean age was 55 years, 42% were women, and 23.6% of the patients were dialyzed with AN69 membranes. There was a significant reduction in pre- and postdialysis SBP and DBP at three and six months. Fifteen patients discontinued the study due to adverse reactions related to losartan, and in seven of them the adverse reaction was hypotension. Only two patients have reported a possible anaphylactoid reaction on treatment with AN69, in one of them the HD session had to be stopped and losartan was discontinued. On the contrary, nine patients with a history of previous anaphylactoid reaction, with ACEIs and AN69, have not shown this complication with losartan and AN69. We conclude that losartan is a well tolerated antihypertensive by HD patients, with a very low incidence of adverse reactions, and a lower prevalence of anaphylactoid reactions than those detected with ACEIs and AN69.
    Kidney international. Supplement 01/1999; 68:S125-9.
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    ABSTRACT: The aim of this study was to find out the relationship between body iron stores and serum aluminum levels among 82 stable CAPD patients. The influence of other factors such as time on CAPD and residual renal function was also considered. Thirty-three patients received aluminum hydroxide as a phosphate binder, and they had significantly higher aluminum levels (36.45 microg/l) than the patients who were not taking aluminum preparations (17.2 microg/l, p = 0.001). A statistically-significant correlation between serum aluminum levels and residual renal function and time on CAPD was also observed (p <0.05). However, there was no relationship between serum aluminum levels and serum iron, ferritin and transferrin saturation, neither between body iron stores and total excretion of aluminum (p >0.05). In previous reports, low serum iron levels were associated with high serum aluminum concentration among hemodialysis patients. However, this effect was not observed in the CAPD population under study. The highest risk of hyperaluminemia was found in the patients who were taking aluminum hydroxide, had worse residual renal function and had been longer on CAPD.
    Clinical nephrology 08/1998; 50(2):77-83. · 1.29 Impact Factor
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    ABSTRACT: The i-PTH response to changes in the peritoneal calcium balance was studied prospectively in a group of 13 stable CAPD patients, who presumably had adynamic bone disease, with low or normal i-PTH values and low aluminum in plasma. Five days after the reduction of dialysate calcium concentration from 1.75 mmol/l to 1 mmol/l, there was a significant elevation in the serum i-PTH. These increased PTH levels returned to baseline values when patients were changed to the 1.75 mmol/l Ca solution (p = 0.004). The changes in i-PTH mirrored the changes in peritoneal calcium balances. These results support the notion that the low or normal levels of i-PTH frequently seen in peritoneal dialysis patients are due to the hypercalcemic effects of the standard peritoneal dialysis solutions; in these patients, the parathyroid hormone production is normal since negative peritoneal balances of calcium are associated with an increase in serum i-PTH.
    Clinical nephrology 01/1998; 48(6):359-63. · 1.29 Impact Factor
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    ABSTRACT: Diabetic patients on dialysis have lower levels of parathyroid hormone (PTH); however, there is no data regarding PTH levels with different degrees of chronic renal failure (CRF). We compared 58 diabetic patients with different degrees of CRF with 268 non-diabetic patients with CRF (serum creatinine >1.2 mg/dl). In both groups, we investigated the main biochemical parameters together with plasma calcium, phosphorus, magnesium, PTH and calcitriol. Diabetic patients showed lower levels of PTH than non-diabetics (P=0.003). The differences were observed in patients with creatinine clearance <70ml/min. We also observed differences in phosphorus, magnesium and tubular resorption of phosphate. In the group of diabetic patients, serum glucose correlated inversely with PTH. Our study suggests that poor control of diabetes (hyperglycaemia) may play a role in the pathogenesis of the hypoparathyroidism observed in patients with diabetes and CRF.
    Nephrology Dialysis Transplantation 01/1998; 13 Suppl 3:9-11. · 3.37 Impact Factor
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    ABSTRACT: Secondary hyperparathyroidism (HPT) was evaluated in 157 patients with chronic renal failure (CRF). It was noted that HPT developed early in CRF at a time when plasma calcium and phosphorous were within normal limits. As creatinine clearance decreased below 80 mL/m, there was a significant decrease in plasma calcitriol and a slow and progressive significant increment in plasma parathyroid hormone (PTH). The effect of dietary intake of calcium and phosphorous was evaluated in these patients with early renal failure (ERF). They were divided into two groups. Group A was placed on a protein- and phosphorous-restricted diet (10 days) followed by a daily phosphorous-load diet (10 days). Group B had similar sequential diets plus a calcium supplement throughout the study. Dietary protein and phosphorous restriction resulted in an amelioration of the HPT only in the group of patients receiving calcium supplementation. The phosphate-load diet resulted in worsening of HPT in both groups. In summary, a deficit of calcitriol occurs early in CRF, which in turn leads to a significant increase in PTH. Phosphorous restriction, together with calcium supplementation, ameliorated the HPT of patients with ERF.
    American Journal of Kidney Diseases 05/1997; 29(4):496-502. · 5.29 Impact Factor
  • Nephron 02/1997; 76(2):239-41. · 13.26 Impact Factor
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    ABSTRACT: Renal function impairment and electrolyte disorders in hypothyroidism are frequently subtle and rarely observed in clinical practice. To assess the extent of these defects, serum concentration of electrolytes and glomerular filtration rate were estimated before and after thyroid replacement therapy in 41 patients with primary hypothyroidism. All patients had decreased glomerular filtration rates and 22 patients had increased serum creatinine levels. Although a relationship between creatinine clearance and serum thyrothropin-stimulating hormone was not found, a weak correlation between age and serum creatinine concentration was observed. Hyponatremia was documented in 45% of 22 patients with elevated serum creatinine but in only 21% of 19 patients with normal creatinine. All these defects were corrected by treatment with thyroid hormone. We conclude that creatinine clearance was slightly decreased in all patients with hypothyroidism, this decrease being more noticeable in elderly patients. The greater the impairment in renal function, the more common was the occurrence of hyponatremia.
    American Journal of Kidney Diseases 03/1996; 27(2):195-8. · 5.29 Impact Factor
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    ABSTRACT: Secondary hyperparathyroidism (HPT) develops early in chronic renal failure (CRF) at a time when plasma calcitriol levels are normal. At this time, PTH are higher than normal controls and serum phosphorous levels are lower. A decrement in total serum Ca is noted, after an oral phosphate load, only in patients with ERF. These data suggest that factors, other than a decrease in calcitriol synthesis, may be involved in the pathogenesis of HPT. A hypothesis is forwarded suggesting that an alteration in the newly cloned calcium sensor receptor may be the earliest abnormality in the HPT, preceding a decrease in plasma calcitriol levels.
    Nephrology Dialysis Transplantation 02/1996; 11 Suppl 3:22-8. · 3.37 Impact Factor
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    ABSTRACT: Candida peritonitis was treated with fluconazole in ten continuous ambulatory peritoneal dialysis (CAPD) patients without immediate removal of the peritoneal catheter. Shortly prior to diagnosis, six patients (60%) had received broad-spectrum antibiotics. Gram stain of peritoneal fluid detected yeast in 70% of cases. In eight patients the peritoneal dialysis catheter was removed within one week of diagnosis because of clinical deterioration. In the majority of cases (90%), candida peritonitis resolved only after catheter removal in spite of ongoing fluconazole therapy. Fluconazole was well tolerated by all patients.
    Clinical nephrology 08/1995; 44(1):60-3. · 1.29 Impact Factor