| 1. |
- Arnadottir, Margret, et al.
(författare)
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The postdialytic rise in the plasma total homocysteine concentration is delayed
- 2002
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Ingår i: Blood Purification. - : S. Karger AG. - 0253-5068 .- 1421-9735. ; 20:4, s. 334-337
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND/AIMS: The mechanism behind the uremic hyperhomocysteinemia has not been elucidated. Possibly, dialyzable uremic toxins play a role, e.g. as enzyme inhibitors. If so, the conditions for enzymatic removal would be expected to improve after dialysis. Therefore, we studied the postdialytic pattern of the plasma total homocysteine (tHcy) concentration. METHODS: We collected blood samples from 19 stable, vitamin-supplemented hemodialysis patients before and at 5, 60, as well as at 480 min after a dialysis session. The patients were studied after dialysis with a low-flux dialyzer (Polyflux 6L) and a high-flux dialyzer (Polyflux 14S). RESULTS: The mean predialytic plasma tHcy concentration was 13.3 micromol/l which is considerably lower than the concentrations observed in our previous studies. In all patients, the plasma tHcy concentration fell during treatment with both types of dialyzers (average decrease 28 +/- 7%, p < 0.0001, and 31 +/- 8%, p < 0.0001, respectively). No postdialytic change in the plasma tHcy concentration was observed at 60 min after low-flux dialysis, however, after high-flux dialysis, the plasma tHcy concentration was significantly lower at 60 min postdialysis than at 5 min (3 +/- 8%, p < 0.05). At 480 min after dialysis, a significant postdialytic increase in the plasma tHcy concentration was found (6 +/- 9%, p < 0.01, and 11 +/- 5%, p < 0.0001, respectively) both in the case of low-flux and high-flux treatment. CONCLUSION: In the postdialytic phase, we observed a short-lived stability in the plasma tHcy concentration, and in the case of high-flux dialysis, even a slight decrease in the plasma tHcy concentration. The results support the hypothesis that dialyzable substances interfere with homocysteine removal.
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| 2. |
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| 3. |
- Nascimento, MM, et al.
(författare)
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Inflammation, malnutrition and atherosclerosis in end-stage renal disease: a global perspective
- 2002
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Ingår i: Blood purification. - : S. Karger AG. - 0253-5068 .- 1421-9735. ; 20:5, s. 454-458
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Tidskriftsartikel (refereegranskat)abstract
- End-stage renal disease (ESRD) is characterized by an exceptional cardiovascular mortality rate. Although traditional risk factors are common in ESRD patients, they alone may not be sufficient to account for the high prevalence of cardiovascular disease (CVD). Recent evidence demonstrated that chronic inflammation, a non-traditional risk factor which is commonly observed in ESRD patients, may cause malnutrition and progressive atherosclerotic CVD by several pathogenetic mechanisms. Although both malnutrition and inflammation have been shown to be strong predictors of cardiovascular mortality in ESRD patients, it must be remembered that the majority of studies describing the presence of inflammation and malnutrition have been performed in Western and Asian industrialized countries. As it is evident that the prevalence of malnutrition and inflammation may differ markedly between different regions of the world and developing countries face a much higher prevalence of chronic infectious diseases, comparative inter-regional studies focusing on the etiology and prevalence of the malnutrition, inflammation and atherosclerosis syndrome are warranted.
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| 4. |
- Nyhlen, Kristina, et al.
(författare)
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Leukocyte sequestration in isolated guinea pig lungs during extracorporeal circulation : effects on microvascular function
- 2000
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Ingår i: Blood Purification. - : S. Karger AG. - 0253-5068 .- 1421-9735. ; 18:2, s. 121-127
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Tidskriftsartikel (refereegranskat)abstract
- Neutrophils accumulate in patient lungs during clinical hemodialysis and in isolated blood-perfused guinea pig lungs due to the contact between blood and extracorporeal system. However, it is unclear how these sequestered and partly activated neutrophils affect the lung microvasculature. We, therefore, studied pulmonary vascular resistance, vascular permeability, gas exchange, and oxygen free radical production in isolated guinea pig lungs during perfusion with whole blood containing partly ‘activated’ neutrophils in comparison with perfusions using leukopenic blood. We also connected a Cuprophan hemodialysis membrane to the whole-blood perfusion system in order to investigate whether a dialyzer, which may further activate leukocytes, affects lung microvascular permeability, vascular resistances, and reactive oxygen species production. The sequestered neutrophils did not seem to markedly affect the lung microvascular function, since neither the leukocyte-free perfusion nor the hemodialysis membrane altered any of the measured variables as compared with whole-blood perfusion in a system without a dialyzer. We conclude that neutrophils, whether activated by a perfusion system or by a dialysis membrane, can accumulate in isolated lungs without adversely affecting the microvascular function.
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| 5. |
- Pecoits, R, et al.
(författare)
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Impact of residual renal function on volume status in chronic renal failure
- 2004
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Ingår i: Blood purification. - : S. Karger AG. - 0253-5068 .- 1421-9735. ; 22:3, s. 285-292
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Tidskriftsartikel (refereegranskat)abstract
- During the past few years, it has become increasingly evident that residual renal function (RRF) is an important and independent predictor of poor outcome in patients with chronic kidney disease (CKD). Although the causes of this observation are not fully understood, it appears that the loss of RRF impairs both fluid removal and clearance of solutes, which in turn leads to uremic toxicity and increased morbidity and mortality. There is increasing evidence that patients with CKD develop signs of fluid overload already in the early phases of the disease, and this may be a stimulus for inflammatory activation. Recently, an inflammatory component was identified in uremic atherosclerotic and non-atherosclerotic cardiovascular disease (CVD), which have been consistently associated with poor clinical outcome in patients with CKD. Signs of systemic inflammation occur in parallel to the impairment in renal function, and the pathophysiology is most likely multifactorial, including a decrease in cytokine clearance, advanced glycation end-product accumulation, oxidative stress, and principal fluid overload. Additionally, inflammation seems to be a predictor of accelerated loss of renal function. In this article, we discuss the evidence showing that patients with CKD generally have fluid overload, the mechanisms by which impaired renal function may lead to a chronic inflammatory state, and the available information linking fluid overload to accelerated loss of renal function and CVD through inflammation. Inflammation may lead to the development of complications of CKD, in particular CVD, but on the other hand may also lead to a faster progression of renal disease. Strategies aiming to reduce fluid overload may be useful to reduce cardiovascular morbidity and mortality, but also preserve RRF.
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| 6. |
- Stenvinkel, P
(författare)
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Inflammatory and atherosclerotic interactions in the depleted uremic patient
- 2001
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Ingår i: Blood purification. - : S. Karger AG. - 0253-5068 .- 1421-9735. ; 19:1, s. 53-61
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Tidskriftsartikel (refereegranskat)abstract
- Despite the improvements in dialysis technology, the cardiovascular mortality rate is still unacceptably high among dialysis patients. It is obvious that traditional risk factors, such as hypertension, chronic heart failure (CHF), dyslipidemia and diabetes mellitus, may account for a large part of the increased cardiovascular mortality rate in these patients. However, based on recent research it could be speculated that other, non-traditional risk factors might also contribute to the high cardiovascular mortality rate in dialysis patients. Chronic inflammation, as evidenced by increased levels of pro-inflammatory cytokines and C-reactive protein (CRP), is a common feature in dialysis patients and is associated with an increased cardiovascular morbidity and mortality. Indeed, elevated levels of pro-inflammatory cytokines (such as TNF-α, IL-1 and IL-6) may cause malnutrition and progressive atherosclerotic cardiovascular disease by several pathogenetic mechanisms, which will be discussed in this review. Based on the strong associations observed between malnutrition, inflammation and atherosclerosis in patients with chronic renal failure (CRF) we have proposed that these features constitute a specific syndrome (MIA), which carries a high mortality rate. As elevated levels of pro-inflammatory cytokines may play a central part in the vicious circle of malnutrition, inflammation and atherosclerosis, further research is needed to investigate whether or not different anti-cytokine treatment strategies may improve survival in dialysis patients.
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| 7. |
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| 8. |
- Waniewski, J, et al.
(författare)
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Fractional solute removal and KT/V in different modalities of renal replacement therapy
- 2004
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Ingår i: Blood purification. - : S. Karger AG. - 0253-5068 .- 1421-9735. ; 22:4, s. 367-376
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Tidskriftsartikel (refereegranskat)abstract
- The efficacy of solute removal by renal replacement therapy can be assessed by the commonly used index of KT/V (the fraction of the volume cleared from a solute). Fractional solute removal (FSR, the fraction of the total amount of the solute that was removed) is an alternative index that may be more appropriate than KT/V for comparison of the efficacy of different treatment modalities. To elucidate the relationship between these two indexes, we propose to discriminate between two notions of clearance: (1) <i>instantaneous clearance</i> K = (solute removal rate)/C<sub>B</sub>, where C<sub>B</sub> is solute concentration in blood, and (2) <i>treatment clearance</i> K<sub>T</sub> = (average rate of solute removal per treatment)/C<sub>B0</sub>, where C<sub>B0</sub> is C<sub>B</sub> at the beginning of the treatment. K is the clearance of the purification device (glomeruli, hemodialyzer or hemofilter) and the diffusive mass transport parameter (K<sub>BD</sub>, MTAC) for continuous ambulatory peritoneal dialysis (CAPD). For all modalities of renal replacement therapy: FSR = K<sub>T</sub>T/V, and K<sub>T</sub> generally decreases with the treatment time. For purification of a single compartment with a constant volume, V, using an open loop system (i.e. with no recirculation or dwelling of dialysis fluid, as in hemodialysis (HD), hemofiltration (HF) or in the native kidney), FSR is a function of only one lumped, nondimensional parameter, KT/V<sub>B</sub>, where V<sub>B</sub> is the distribution volume of the solute within the body. In contrast, if closed loop systems are applied, as for example in HD with recirculation of dialysis fluid (RD) or in peritoneal dialysis, FSR depends on two lumped, nondimensional parameters: KT/V<sub>B</sub> and KT/V<sub>D</sub>, where V<sub>D</sub> is the volume of dialysis fluid. It is necessary to discriminate between K and K<sub>T</sub> for analysis of dialysis dose. For HD and HF, FSR is a function of KT/V, whereas KT/V alone does not allow calculation of FSR for CAPD and RD. The current practice of using K<sub>T</sub>T/V for CAPD but KT/V for HD and HF leads to confusion because of the inconsistency in the interpretation of the quantitative prescription of dialysis dose. The application of FSR, instead of KT/V, for all treatment modalities may solve this dilemma. Furthermore, K<sub>T</sub>T/V (currently used only for CAPD) is equal to FSR for all treatment modalities. Both FSR and K<sub>T</sub> may be generalized to describe the total solute removal per treatment cycle composed from a few treatment sessions. A few different definitions of the adequacy parameters for the treatment cycle are formulated and discussed.
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