Rob M Valentijn

HagaZiekenhuis van Den Haag, 's-Gravenhage, South Holland, Netherlands

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Publications (10)9.13 Total impact

  • 03/2013; 33(2):208-12. DOI:10.3747/pdi.2012.00097
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    ABSTRACT: Glucose and glucose degradation products (GDPs) in peritoneal dialysis fluids (PDFs) are both thought to mediate progressive peritoneal worsening. In a multicenter, prospective, randomized crossover study, incident continuous ambulatory peritoneal dialysis patients were treated either with conventional lactate-buffered PDF (sPD regimen) or with a regimen low in glucose and GDPs: Nutrineal×1, Extraneal×1, and Physioneal×2 (NEPP regimen; all solutions: Baxter Healthcare, Utrecht, The Netherlands). After 6 months, patients were switched to the alternative regimen for another 6 months. After 6 weeks of run-in, before the switch, and at the end of the study, 4-hour peritoneal equilibration tests were performed, and overnight effluents were analyzed for cells and biomarkers. Differences between the regimens were assessed by multivariate analysis corrected for time and regimen sequence. The 45 patients who completed the study were equally distributed over both groups. During NEPP treatment, D(4)/D(0) glucose was lower (p < 0.01) and D/P creatinine was higher (p = 0.04). In NEPP overnight effluent, mesothelial cells (p < 0.0001), cancer antigen 125 (p < 0.0001), hyaluronan (p < 0.0001), leukocytes (p < 0.001), interleukins 6 (p = 0.001) and 8 (p = 0.0001), and vascular endothelial growth factor (VEGF, p < 0.0001) were increased by a factor of 2-3 compared with levels in sPD effluent. The NEPP regimen was associated with higher transport parameters, but that association disappeared after the addition of VEGF to the model. The association between NEPP and higher effluent levels of VEGF could not be attributed to glucose and GDP loads. Study results indicate preservation of the mesothelium and increased peritoneal activation during NEPP treatment. Whether the increase in VEGF reflects an increase in mesothelial cell mass or whether it points to another, undesirable mechanism cannot be determined from the present study. Longitudinal studies are needed to finally evaluate the usefulness of the NEPP regimen for further clinical use.
    11/2011; 32(3):305-15. DOI:10.3747/pdi.2010.00115
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    ABSTRACT: Standard peritoneal dialysis (PD) solutions contain high levels of glucose and glucose degradation products (GDPs), both contributing to the formation of advanced glycation end products (AGEs). We studied the contribution to plasma GDP and AGE levels of 2 PD regimens that differ in glucose and GDP loads: high load [standard PD (sPD) using 4 glucose-lactate exchanges] and low load [1 amino acid exchange, 1 icodextrin exchange, and 2 glucose-bicarbonate/lactate exchanges ("NEPP")]. In a prospective crossover study (2 periods of 24 weeks), new continuous ambulatory PD patients were randomized to NEPP-sPD (n = 23) or to sPD-NEPP (n = 27). After the start of PD, absolute increases were observed in plasma levels of 3-deoxyglucosone (3-DG, 220.4 nmol/L, p < 0.0001) and in N(ε)-(carboxymethyl) lysine (CML) in plasma proteins (0.02 μmol/L CML per 1 mol/L lysine, p < 0.0001). During the first 6 weeks, 3-DG tended to increase more with sPD treatment (p = 0.08), and CML, with NEPP treatment (p = 0.002). In both groups, N(ε)-(carboxyethyl)lysine (CEL) in plasma proteins declined significantly with the start of PD. Treatment with NEPP resulted in higher levels of methylglyoxal (MGO) and lower levels of 3-DG and CEL. Pentosidine in the albumin fraction tended to increase less during NEPP treatment. A low glucose and GDP PD regimen (NEPP) resulted in plasma levels of 3-DG and CEL that were lower than those with a glucose-based sPD regimen. Starting PD with NEPP was associated with a steeper increase in CML, and continuing treatment with NEPP resulted in higher MGO levels.
    05/2011; 32(1):45-54. DOI:10.3747/pdi.2010.00101
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    ABSTRACT: Self-regulation theory explains how patients' illness perceptions influence self-management behaviour (e.g. via adherence to treatment). Following these assumptions, we explored whether illness perceptions of ESRD-patients are related to mortality rates. Illness perceptions of 182 patients participating in the NECOSAD-2 study in the period between December 2004 and June 2005 were assessed. Cox proportional hazard models were used to estimate whether subsequent all-cause mortality could be attributed to illness perception dimensions. One-third of the participants had died at the end of the follow-up. Mortality rates were higher among patients who believed that their treatment was less effective in controlling their disease (perceived treatment control; RR = 0.71, P = 0.028). This effect remained stable after adjusting for sociodemographic and clinical variables (RR = 0.65, P = 0.015). If we consider risk factors for mortality, we tend to rely on clinical parameters rather than on patients' representations of their illness. Nevertheless, results from the current exploration may suggest that addressing patients' personal beliefs regarding the effectiveness of treatment can provide a powerful tool for predicting and perhaps even enhancing survival.
    Nephrology Dialysis Transplantation 05/2009; 24(10):3183-5. DOI:10.1093/ndt/gfp184 · 3.49 Impact Factor
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    T M Slee, L J Vleming, R M Valentijn
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    ABSTRACT: Case report of a 62-year-old woman who developed acute renal failure due to nephrocalcinosis, also called acute phosphate nephropathy, after large bowel cleansing in preparation for colonoscopy using oral sodium phosphate solution (Phosphoral, de Witt, Cheshire, UK). Subsequently her renal insufficiency resolved only partially resulting in stage 4 chronic kidney disease. In retrospect multiple risk factors for this condition (hypertension, diuretics, AT-II receptor blocker, female gender, advanced age and volume depleting due to vomiting and nausea) were identified. If these factors had been taken into consideration prior to prescribing this drug, acute and chronic renal failure would have been prevented. Future investigation of potential risk factors and the exact mechanism of this complication is necessary to identify those patients prone to develop this complication. In the meantime prescribing physicians should be made aware of this complication. On the basis of the current state of knowledge the evidence seems to be quite compelling not to prescribe these drugs in patients with one or more associated risk factors. It could even be argued that these drugs should not be prescribed at all.
    The Netherlands Journal of Medicine 12/2008; 66(10):438-41. · 2.21 Impact Factor
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    ABSTRACT: To evaluate acute effects of hemodialysis (HD) on the salivary flow rate, pH and biochemical composition before, during and after completion of a dialysis session. Unstimulated whole saliva (UWS) and chewing-stimulated whole saliva (CH-SWS) were collected in 94 HD patients. Salivary flow rate, pH, concentrations of total protein, albumin, cystatin C, secretory immunoglobulin A (S-IgA) and of sodium, potassium and urea were measured. HD had an acute stimulating effect on the salivary flow rate (UWSbefore = 0.30+/-0.22 ml/min, UWSduring = 0.39+/-0.25 ml/min, p < 0.005). The mean pH of UWS showed a small but significant increase during HD mainly due to an increased watery secretion from the salivary glands. The salivary biochemical constituents changed markedly, but no significant difference in output was found. The electrolyte concentration did not change significantly during dialysis. The level of urea in CH-SWS declined to 40% (Ureabefore = 25.+/-6.4 mmol/l, Ureaduring = 15.3+/-4.5 mmol/1). This study shows that HD has significant acute effects on both salivary secretion rate and protein concentrations in saliva. We conclude that the observed changes in salivary concentrations and proteins are mainly due to an increased watery secretion from the salivary glands.
    Clinical nephrology 01/2007; 67(1):25-31. DOI:10.5414/CNP67025 · 1.23 Impact Factor
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    ABSTRACT: The high Levels of glucose, glucose degradation products (GDPs), and lactate buffer present in standard peritoneal dialysis (PD) solutions contribute to peritoneal damage, malnutrition, and dyslipidemia. Therefore, we studied the feasibility of a PD regimen as low as possible in glucose and GDPs. In a prospective 30-week study, patients new to continuous ambulatory PD (CAPD) were randomized to either a standard PD regimen (SPD; 4 dwells glucose-/lactate-based) or a low glucose-GDP regimen (NEPP; 1 dwell amino acids, 1 dwell icodextrin, and two dwells bicarbonate/lactate-buffered glucose-based solution). Results obtained during a 30-week study period for 63 new CAPD patients (30 NEPP, 33 SPD) were analyzed. Intraperitoneal glucose load was lower in the NEPP group (111 +/- 76 vs 159 +/- 40 g/day at 30 weeks, p < 0.001). Dialysis efficacy, ultrafiltration, weight, blood pressure, and laboratory results were similar in the groups, whereas, in the NEPP group, cancer antigen 125 in dialysate effluents decreased less but dialysate-to-plasma ratios were slightly higher. Short-term treatment of new CAPD patients with a PD regimen low in glucose and GDPs is feasible. Dialysis efficacy, ultrafiltration, and metabolic consequences are similar to those during a standard glucose-lactate-based regimen, whereas peritoneal transport seems slightly higher and preservation of mesothelial cell mass better during NEPP.
    Peritoneal dialysis international: journal of the International Society for Peritoneal Dialysis 03/2005; 25 Suppl 3:S64-8. · 2.20 Impact Factor
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    ABSTRACT: Standard glucose-based peritoneal dialysis (PD) solutions have unfavorable effects on the peritoneum and contribute to metabolic abnormalities. A PD regimen in which solutions with an alternative osmotic agent (icodextrin, amino acids) and solutions with a bicarbonate/lactate buffer are combined may reduce those effects. In a prospective crossover study, we randomized new continuous ambulatory peritoneal dialysis (CAPD) patients to one of two groups. One group used 4 exchanges of standard PD (SPD) solution (Dianeal: Baxter Healthcare BV, Utrecht, Netherlands) daily. The second group used 1 exchange of Nutrineal (Baxter Healthcare BV), 1 exchange of Extraneal (Baxter Healthcare BV), and 2 exchanges of Physioneal (Baxter Healthcare BV) daily (NEPP). After 30 weeks of treatment, each group switched over to the other regimen for 24 weeks. Statistical analysis used analysis of variance (ANOVA) for repeated measurements. Of the 74 patients enrolled into the study, 50 completed the full study period (24 NEPP-SPD, 26 SPD-NEPP). With regard to daily ultrafiltration and dialysis efficacy (Kt/V), the NEPP regimen was as efficacious as the standard regimen. The NEPP regimen was found to be safe: body weight, blood pressure, decline in urine volume, residual creatinine clearance, and laboratory measurements did not differ statistically significantly from those measured in the standard regimen. The NEPP regimen was well tolerated and was not accompanied by serious side effects. During the NEPP regimen, bicarbonate was found to be significantly higher in both groups. The NEPP regimen is a feasible treatment schedule for patients starting CAPD.
    Advances in peritoneal dialysis. Conference on Peritoneal Dialysis 02/2004; 20:170-6.
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