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Andrew Davenport - One of the best experts on this subject based on the ideXlab platform.
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the effect of glucose absorption from peritoneal Dialysates on changes in lipid profiles in prevalent peritoneal dialysis patients
Peritoneal Dialysis International, 2021Co-Authors: Steven Law, Andrew DavenportAbstract:The majority of peritoneal Dialysates contain glucose, which can potentially be absorbed from the peritoneal cavity. Previous studies have reported an observation between dialysate glucose exposure...
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comparison of skin autofluorescence a marker of tissue advanced glycation end products in peritoneal dialysis patients using standard and biocompatible glucose containing peritoneal Dialysates
Nephrology, 2019Co-Authors: Surachet Vongsanim, Stanley L Fan, Andrew DavenportAbstract:Background Heat sterilization of peritoneal dialysis (PD) Dialysates leads to the generation of advanced glycation products (AGE), which can then deposit in the skin and be measured by skin autofluorescence (SAF). Newer biocompatible dual chamber Dialysates contain less AGE. We wished to determine whether the use of these newer Dialysates resulted in lower SAF. Methods Skin autofluorescence was measured using the AGE reader, which directs ultraviolet light, intensity range 300-420 nm (peak 370 nm) in patients established on PD for >3 months using glucose containing Dialysates. Results We screened 196 consecutive patients, and measured SAF in 150; 86 (57.3%) male, median age 62 (53-71) years, median duration of PD treatment 17 (8.6-34.3) months. The median SAF was 3.48 (2.92-4.26) AU. The median SAF in the 57 (38%) patients prescribed biocompatible dual chamber bag Dialysates was 3.39 (2.69-3.98) versus 3.5 (3.05-4.54) for those using standard Dialysates (P = 0.044). Although prescription of biocompatible fluids was associated with SAF on univariate analysis, but not on multivariable testing, SAF was independently associated with Stoke-Davies co-morbidity grade (β 0.045, 95% confidence limits (CL) 0.015-0.075, P = 0.002), log duration of PD therapy (β 0.051, CL 0.001-0.101, P = 0.045), white ethnicity (β 0.066, CL 0.028-0.104, P = 0.001), and negatively with serum albumin (β -0.006, CL -0.008 to -0.004, P = 0.014). Conclusion Although SAF was lower in PD patients prescribed biocompatible dual chamber Dialysates, on multivariable testing these Dialysates were not independently associated with SAF. Other factors than PD fluid AGE content appear more important in determining SAF.
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comparison of skin autofluorescence a marker of tissue advanced glycation end products in peritoneal dialysis patients using standard and biocompatible glucose containing peritoneal Dialysates
Nephrology (2018) (In press)., 2018Co-Authors: Surachet Vongsanim, Stanley L Fan, Andrew DavenportAbstract:BACKGROUND: Heat sterilisation of peritoneal dialysis (PD) Dialysates leads to the generation of advanced glycation products (AGEs), which can then deposit in the skin and be measured by skin autofluorescence (SAF). Newer biocompatible dual chamber Dialysates contain less AGEs. We wished to determine whether the use of these newer Dialysates resulted in lower SAF. METHODS: SAF was measured using the AGE reader, which directs ultraviolet light, intensity range 300-420 nm (peak 370 nm) in patients established on PD for > 3 months using glucose containing Dialysates. RESULTS: We screened 196 consecutive patients, and measured SAF in 150; 86(57.3%) male, median age 62 (53-71) years, median duration of PD treatment 17 (8.6-34.3) months. The median SAF was 3.48 (2.92-4.26) AU. The median SAF in the 57 (38%) patients prescribed biocompatible dual chamber bag Dialysates was 3.39 (2.69-3.98) vs 3.5 (3.05-4.54) for those using standard Dialysates (p=0.044). Although prescription of biocompatible fluids was associated with SAF on univariate analysis, but not on multivariable testing, SAF was independently associated with Stoke-Davies co-morbidity grade (β 0.045, 95% confidence limits (CL) 0.015 to 0.075, p=0.002), log duration of PD therapy (β 0.051, CL 0.001 to 0.101, p=0.045), white ethnicity (β 0.066, CL 0.028 to 0.104, p=0.001), and negatively with serum albumin (β -0.006, CL -0.008 to -0.004, p=0.014) CONCLUSIONS: Although SAF was lower in PD patients prescribed biocompatible dual chamber Dialysates, on multivariable testing these Dialysates were not independently associated with SAF. Other factors than PD fluid AGE content appear more important in determining SAF.
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why does the choice of dialysate sodium concentration remain controversial
Hemodialysis International, 2018Co-Authors: Kamonwan Tangvoraphonkchai, Andrew DavenportAbstract:The choice of the ideal dialysate sodium concentration remains controversial. Most dialysis centers have a standard dialysate concentration. In theory, choosing a dialysate sodium concentration lower than serum sodium should result in an additional loss of sodium by diffusion with a reduction in the prevalence of hypertension and interdialytic weight gains (IDWGs) on one hand, but with potential increased risk of intradialytic hypotension and cramps on the other hand, and the opposite effects may accompany the choice of dialysate sodium concentrations greater than serum concentration. Although most studies have reported a reduction in IDWG with lower dialysate sodium concentrations, the effects on blood pressure control, and adverse intradialytic events have been variable. Different outcomes between studies may be partially explained by patient selection, with differences in dietary sodium intake, urinary sodium losses, and sodium stores in the body. In addition, multicenter trials potentially introduce additional confounders, including differences in local quality control of delivered dialysate sodium concentration and sodium measurements. Although there may be advantages for lower dialysate sodium concentration, observational studies have reported a survival advantage for higher dialysate sodium concentrations for those patients with lower serum sodium concentrations pre-dialysis. As there is no current consensus for a universal dialysate sodium concentration, attention has turned to considering an individualized approach to choosing a dialysate sodium concentration.
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Reliability of delivered dialysate sodium concentration.
Hemodialysis International, 2016Co-Authors: Nasirul J. Ekbal, Jahm Persaud, Anne Consalus, Andrew DavenportAbstract:Background The results of studies investigating the effects of hyponatraemic Dialysates have been mixed, with some reporting positive effects including reduction in blood pressure and inter-dialytic weight gains, whereas others have not been able to demonstrate any effect. These studies assume that setting a lower dialysate sodium results in the delivery of a hyponatraemic dialysate. We therefore measured delivered sodium to determine reliability. Methods We measured dialysate sodium in 10 BBraun Dialog+® and 6 Fresenius 4008H dialysis machines, which had been set up to deliver a sodium of 136 mmol/L, using flame photometry and indirect ion selective electrode (ISE) methods. Results Dialysate conductivity was 13.85 ± 0.05 mS/cm, but dialysate sodium measured by flame photometry was 141.8 ± 2.9 mmol/L, and 142.5 ± 2.4 mmol/L by ISE. Both dialysis machines delivered a dialysate sodium in excess of the 136 mmol/L set, with a mean bias of 7.0 ±2.1 mmol/L for the Dialog+®, and 3.7 ± 2.6 for the 4008 with the flame photometer method, and a mean bias of 6.3 ± 1.3 mmol/L for the Dialog+®, and 6.8 ± 3.7 for the 4008 by ISE. Conclusion It is assumed when setting a dialysate sodium concentration that this sodium concentration is delivered. However we found that the dialysate sodium concentration delivered was greater than that set, despite the dialysis machines reporting a conductivity measurement in keeping with a lower sodium dialysate. Trials of lowered dialysate sodium therefore need to measure dialysate sodium concentrations to ensure what has been set is delivered.
Robert T Kennedy - One of the best experts on this subject based on the ideXlab platform.
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simultaneous oxytocin and arg vasopressin measurements in microDialysates using capillary liquid chromatography mass spectrometry
Journal of Neuroscience Methods, 2012Co-Authors: Omar S Mabrouk, Robert T KennedyAbstract:Abstract Oxytocin (OXT) and arg-vasopressin (AVP) are nonapeptides with many important functions both peripherally and centrally. Intracerebral microdialysis has helped characterize their importance in regulating complex social and emotional processes. Radioiummunoassay is the most commonly used analytical method used for OXT and AVP measurements in microDialysates. These measurements have several well-known issues including single peptide per assay limit, possible cross-reactivity between structurally related peptides, and laborious sample preparation with radioactive materials. Here we demonstrate the use of capillary LC–MS3 for measuring OXT and AVP simultaneously in Dialysates at a 10 min sampling frequency. Microdialysate samples required no preparation and instrumentation was commercially available. Microdialysis probes made with polyacrylonitrile membranes were suitable for high level recovery of the peptides in vitro and in vivo. Responses were linear from 1 to 100 pM. Matrix effect was assessed by standard addition experiments and by comparing signal intensities of OXT and AVP standards made in aCSF or dialysate. It was determined that the online washing step used on this setup was adequate for removing contaminants which interfere with electrospray ionization efficiency. In vivo, both peptides were stimulated by high K+ (75 mM) aCSF perfusion in the paraventricular nucleus (PVN). Also, a systemic injection of high Na+ (2 M) caused a rapid and transient increase in PVN OXT while AVP increased only after 1.5 h. Our findings suggest that capillary LC–MS3 is a straightforward method for monitoring OXT and AVP simultaneously from complex samples such as Dialysates.
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monitoring dopamine in vivo by microdialysis sampling and on line ce laser induced fluorescence
Analytical Chemistry, 2006Co-Authors: Minshan Shou, Carrie R Ferrario, Kristin N Schultz, Terry E Robinson, Robert T KennedyAbstract:Microdialysis sampling was coupled on-line to micellar electrokinetic chromatography (MEKC) to monitor extracellular dopamine concentration in the brains of rats. Microdialysis probes were perfused at 0.3 μL/min and the dialysate mixed on-line with 6 mM naphthalene-2,3-dicarboxaldehye and 10 mM potassium cyanide pumped at 0.12 μL/min each into a reaction capillary. The reaction mixture was delivered into a flow-gated interface and separated at 90-s intervals. The MEKC separation buffer consisted of 30 mM phosphate, 6.5 mM SDS, and 2 mM HP-β-CD at pH 7.4, and the electric field was 850 V/cm applied across a 14-cm separation distance. Analytes were detected by laser-induced fluorescence excited using the 413-nm line of a 14-mW diode-pumped laser. The detection limit for dopamine was 2 nM when sampling by dialysis. The basal dopamine concentration in Dialysates collected from the striatum of anesthetized rats was 18 ± 3 nM (n = 12). The identity of the putative dopamine peak was confirmed by showing that dop...
Bovy Christophe - One of the best experts on this subject based on the ideXlab platform.
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Peritoneal equilibration test with conventional 'low pH/high glucose degradation product' or with biocompatible 'normal pH/low glucose degradation product' Dialysates: does it matter?
'Oxford University Press (OUP)', 2013Co-Authors: Van Overmeire Lionel, Goffin Eric, Krzesinski Jean-marie, Saint-remy Annie, Bovy Philippe, Cornet Georges, Bovy ChristopheAbstract:Peritoneal transport of water and small solutes is independent of the type of dialysate which is used. This is not the case for the transport of beta-2-microglobulin and albumin that is higher under biocompatible Dialysates. Vascular tonus modification could potentially explain such differences. The PET should therefore always be carried out with the same dialysate to make longitudinal comparisons possible
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Peritoneal equilibration test with conventional ‘low pH/high glucose degradation product’ or with biocompatible ‘normal pH/low glucose degradation product’ Dialysates: does it matter?
2013Co-Authors: Van Overmeire Lionel, Goffin Eric, Krzesinski Jean-marie, Saint-remy Annie, Bovy Philippe, Cornet Georges, Bovy ChristopheAbstract:Abstract Background. The evaluation of the peritoneal transport characteristics is mandatory in peritoneal dialysis (PD) patients. This is usually performed in routine clinical practice with a peritoneal equilibration test (PET) using conventional Dialysates, with low pH and high glucose degradation product (GDP) concentrations. An increasing proportion of patients are now treated with biocompatible Dialysates, i.e. with physiological pH and lower GDP concentrations. This questions the appropriateness to perform a PET with conventional solutions in those patients. The aim of our study is to compare the results of the PET using biocompatible and conventional Dialysates, respectively. Methods. Nineteen stable PD patients (13 males, 6 females; mean age: 67.95 ± 2.36 years, mean body surface area: 1.83 ± 0.04 m2, dialysis vintage: 2.95 ± 0.19 years) were included, among which 10 were usually treated with biocompatible and 9 with conventional solutions. Two PETs were performed, within a 2-week interval, in each patient. PET sequence (conventional solution first or biocompatible solution first) was randomized in order to avoid ‘time bias’. Small (urea, creatinine and glucose), middle (beta-2-microglobulin) and large molecules’ (albumin and alpha-2-macroglobulin) dialysate/plasma (D/P) concentration ratios and clearances were measured during each PET. Ultrafiltration (UF) and sodium filtration were also recorded. Results of both tests were compared by the Wilcoxon paired test. Results. No statistical difference was found between both Dialysates for small molecule transport rates or for sodium filtration and UF. However, a few patients were not similarly classified for small-solute transport characteristics within the PET categories. Beta-2-microglobulin and albumin D/P ratios at different time points of the PET were significantly higher with the biocompatible, when compared with the conventional, solutions: 0.10 ± 0.03 versus 0.08 ± 0.02 (P < 0.01) and 0.008 ± 0.003 versus 0.007 ± 0.003 (P = 0.01), respectively. A similar difference was also observed for beta-2-microglobulin that was higher with biocompatible Dialysates (1.04 ± 0.32 versus 0.93 ± 0.32 mL/min, respectively). Conclusion. Peritoneal transport of water and small solutes is independent of the type of dialysate which is used. This is not the case for the transport of beta-2-microglobulin and albumin that is higher under biocompatible Dialysates. Vascular tonus modification could potentially explain such differences. The PET should therefore always be carried out with the same dialysate to make longitudinal comparisons possible.Peer reviewe
Surachet Vongsanim - One of the best experts on this subject based on the ideXlab platform.
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comparison of skin autofluorescence a marker of tissue advanced glycation end products in peritoneal dialysis patients using standard and biocompatible glucose containing peritoneal Dialysates
Nephrology, 2019Co-Authors: Surachet Vongsanim, Stanley L Fan, Andrew DavenportAbstract:Background Heat sterilization of peritoneal dialysis (PD) Dialysates leads to the generation of advanced glycation products (AGE), which can then deposit in the skin and be measured by skin autofluorescence (SAF). Newer biocompatible dual chamber Dialysates contain less AGE. We wished to determine whether the use of these newer Dialysates resulted in lower SAF. Methods Skin autofluorescence was measured using the AGE reader, which directs ultraviolet light, intensity range 300-420 nm (peak 370 nm) in patients established on PD for >3 months using glucose containing Dialysates. Results We screened 196 consecutive patients, and measured SAF in 150; 86 (57.3%) male, median age 62 (53-71) years, median duration of PD treatment 17 (8.6-34.3) months. The median SAF was 3.48 (2.92-4.26) AU. The median SAF in the 57 (38%) patients prescribed biocompatible dual chamber bag Dialysates was 3.39 (2.69-3.98) versus 3.5 (3.05-4.54) for those using standard Dialysates (P = 0.044). Although prescription of biocompatible fluids was associated with SAF on univariate analysis, but not on multivariable testing, SAF was independently associated with Stoke-Davies co-morbidity grade (β 0.045, 95% confidence limits (CL) 0.015-0.075, P = 0.002), log duration of PD therapy (β 0.051, CL 0.001-0.101, P = 0.045), white ethnicity (β 0.066, CL 0.028-0.104, P = 0.001), and negatively with serum albumin (β -0.006, CL -0.008 to -0.004, P = 0.014). Conclusion Although SAF was lower in PD patients prescribed biocompatible dual chamber Dialysates, on multivariable testing these Dialysates were not independently associated with SAF. Other factors than PD fluid AGE content appear more important in determining SAF.
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comparison of skin autofluorescence a marker of tissue advanced glycation end products in peritoneal dialysis patients using standard and biocompatible glucose containing peritoneal Dialysates
Nephrology (2018) (In press)., 2018Co-Authors: Surachet Vongsanim, Stanley L Fan, Andrew DavenportAbstract:BACKGROUND: Heat sterilisation of peritoneal dialysis (PD) Dialysates leads to the generation of advanced glycation products (AGEs), which can then deposit in the skin and be measured by skin autofluorescence (SAF). Newer biocompatible dual chamber Dialysates contain less AGEs. We wished to determine whether the use of these newer Dialysates resulted in lower SAF. METHODS: SAF was measured using the AGE reader, which directs ultraviolet light, intensity range 300-420 nm (peak 370 nm) in patients established on PD for > 3 months using glucose containing Dialysates. RESULTS: We screened 196 consecutive patients, and measured SAF in 150; 86(57.3%) male, median age 62 (53-71) years, median duration of PD treatment 17 (8.6-34.3) months. The median SAF was 3.48 (2.92-4.26) AU. The median SAF in the 57 (38%) patients prescribed biocompatible dual chamber bag Dialysates was 3.39 (2.69-3.98) vs 3.5 (3.05-4.54) for those using standard Dialysates (p=0.044). Although prescription of biocompatible fluids was associated with SAF on univariate analysis, but not on multivariable testing, SAF was independently associated with Stoke-Davies co-morbidity grade (β 0.045, 95% confidence limits (CL) 0.015 to 0.075, p=0.002), log duration of PD therapy (β 0.051, CL 0.001 to 0.101, p=0.045), white ethnicity (β 0.066, CL 0.028 to 0.104, p=0.001), and negatively with serum albumin (β -0.006, CL -0.008 to -0.004, p=0.014) CONCLUSIONS: Although SAF was lower in PD patients prescribed biocompatible dual chamber Dialysates, on multivariable testing these Dialysates were not independently associated with SAF. Other factors than PD fluid AGE content appear more important in determining SAF.
Hans Erik Botker - One of the best experts on this subject based on the ideXlab platform.
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release of a humoral circulating cardioprotective factor by remote ischemic preconditioning is dependent on preserved neural pathways in diabetic patients
Basic Research in Cardiology, 2012Co-Authors: Rebekka Vibjerg Jensen, Nicolaj Brejnholt Stottrup, Steen B Kristiansen, Hans Erik BotkerAbstract:Efficacy of ischemic preconditioning is decreased in animal models of type 2 diabetes mellitus while the responses in humans with diabetes are contradictory. It is unknown whether attenuation is related to decreased release of a mediating humoral cardioprotective factor or reduced ability to respond in the target tissue. The aim of the present study was to investigate the release and effect of a circulating cardioprotective factor in type 2 diabetes mellitus patients. Blood samples were drawn from nine non-diabetic subjects, eight diabetic patients without peripheral neuropathy, and eight diabetic patients with peripheral neuropathy before (control) and after a remote ischemic preconditioning (rIPC) stimulus. Blood samples were dialyzed against Krebs–Henseleit buffer and the cardioprotective effects of the Dialysates were tested in rabbit hearts mounted on a Langendorff model and subjected to 30-min global ischemia and 120-min reperfusion. rIPC dialysate from non-diabetic and diabetic subjects without peripheral neuropathy reduced infarct size and improved hemodynamic recovery compared to control dialysate from non-diabetic and diabetic subjects. However, in the subgroup of diabetic patients with neuropathy the cardioprotective effect was attenuated. These findings indicate that the release mechanism involves neural pathways.