Deficiencies of Vitamins in CAPD Patients: The Effect of Supplementation

Concentrations of the vitamins B₁, B₂, B₆, B₁₂, C, folic acid,A, E and ß-carotene were determined in blood and 24-hdialysate in 44 CAPD patients. Twenty-five of these patientswere studied during chronic treatment (mean 313 days, range60–1034 days). Nineteen patients were studied during training.In a longitudinal study, 11 patients were analysed again after77–507 (mean 238) days. In both patient groups a considerable portion of patients (11%–64%)had blood concentrations indicative of a deficiency of the vitaminsB₁, B₆, C and folic acid. The average concentrations of thesevitamins were normal in both groups. The only abnormal findingwas the mean EGOT activity being deficient in patients on chronictreatment. Mean concentrations of vitamin A were above normalin both groups. In the longitudinal study a significant increaseof vitamin B₂ and a decrease of vitamin B₆ in blood was found. When compared to 24-h excretion in normal urine, loss with 24-hdialysate was low for vitamin B₁, normal to relatively highfor vitamin B₂ and B₆, but extremely high for vitamin C andfolic acid. The vitamins B₁₂, A, E and carotenoids were hardlydetectable in the dialysate. In ten other patients the effect of daily supplementation with2 mg vitamin B₆, 100mg vitamin C and 400 µg folic acidwas analysed during a 16-week period. In all patients a significantincrease in blood concentrations was obtained. It is concludedthat these dosages were sufficient to maintain a normal statusof these vitamins in CAPD patients.     

Hyperphosphataemia and related mortality.

Sir, With great interest we read the editorial review of Jean etal. [1] on the relationship between hyperphosphataemia and mortalityin end-stage renal disease patients. The authors summarize resultsfrom the large USRDS and DOPPS studies in which associationsof hyperphosphataemia and increased mortality risks were     

The relationship between local and global processing and the processing of high and low spatial frequencies studied by event-related potentials and source modeling

The processing of global and local elements and of low- and high-spatial frequencies are thought to be interrelated. Evidence for this stems from findings showing that brain localizations for global/local elements and for low/high spatial frequencies seem to overlap. The present study aimed to provide direct evidence that topographical differences between the processing of global and local visual elements can directly be explained by their spatial frequency content, and to study at which point in time this relation is present. This was done by studying the event-related potentials (ERPs) and source models elicited by unfiltered, low- or high-pass filtered hierarchical stimuli. Results showed that performance for global and local targets was affected by removing low and high spatial frequencies, respectively. ERP data indicated that at 250 ms, there was an interaction between the processing of global/local targets and of spatial frequencies because at this time-point removal of low spatial frequencies decreased activity associated with the processing of global targets. When localizing this effect, we found evidence implying that spatial frequency content indeed affected the brain region in which local/global targets were processed. Results implicated that the processing of global information depended on its low spatial frequency content, which was processed more laterally. Instead, processing of local information seemed to depend on its high spatial frequency content, which was processed more medially. Thereby, present results extend former results showing that global and local processing is dependent on spatial frequency and mapped retinotopically in the visual cortex.     

Relative contribution of residual renal function and different measures of adequacy to survival in hemodialysis patients: an analysis of the Netherlands Cooperative Study on the Adequacy of Dialysis (NECOSAD)-2

A high delivered Kt/V(urea) (dKt/V(urea)) is advocated in the U.S. National Kidney Foundation Dialysis Outcomes Quality Initiative guidelines on hemodialysis (HD) adequacy, irrespective of the presence of residual renal function. The contribution of treatment adequacy and residual renal function to patient survival was investigated. The Netherlands Cooperative Study on the Adequacy of Dialysis is a prospective multicenter study that includes incident ESRD patients older than 18 yr. The longitudinal data on residual renal function and dialysis adequacy of patients who were treated with HD 3 mo after the initiation of dialysis (n = 740) were analyzed. The mean renal Kt/V(urea) (rKt/V(urea)) at 3 mo was 0.7/wk (SD 0.6) and the dKt/V(urea) at 3 mo was 2.7/wk (SD 0.8). Both components of urea clearance were associated with a better survival (for each increase of 1/wk in rKt/V(urea), relative risk of death = 0.44 [P < 0.0001]; dKt/V(urea), relative risk of death = 0.76 [P < 0.01]). However, the effect of dKt/V(urea) on mortality was strongly dependent on the presence of rKt/V(urea), low values for dKt/V(urea) of <2.9/wk being associated with a significantly higher mortality in anuric patients only. Furthermore, an excess of ultrafiltration in relation to interdialytic weight gain was associated with an increase in mortality independent of dKt/V(urea). In conclusion, residual renal clearance seems to be an important predictor of survival in HD patients, and the dKt/V(urea) should be tuned appropriately to the presence of renal function. Further studies are required to substantiate the important role of fluid balance in HD adequacy.     

alpha-Galactosidase A deficiency in Dutch patients on dialysis: a critical appraisal of screening for Fabry disease.

INTRODUCTION: Fabry disease or alpha-galactosidase A (alpha-Gal A) deficiency is an X-linked lysosomal storage disorder that often leads to renal insufficiency in males and occasionally in females. The disease is rare, but its prevalence may be underestimated due to its variable clinical picture. Enzyme supplementation therapy with rHu-alphaGal A is currently available. Limited experience has so far shown that therapy may at best stabilize renal function. Despite these preliminary findings, much effort is being put into screening high-risk groups for undiagnosed alpha-Gal A deficiency. We studied the prevalence of alpha-Gal A deficiency in a Dutch dialysis cohort to establish possible underdiagnosis. We discuss the benefits of screening for Fabry disease. METHODS: Activity of alpha-Gal A in whole blood was measured in a group of 508 male Dutch dialysis patients. RESULTS: Of the 508 patients studied only one patient, already known with Fabry disease, had a alpha-Gal A deficiency, a prevalence of 0.22% (95 CI 0-1.1%). CONCLUSIONS: No undiagnosed Fabry patients were found, indicating that in our studied cohort there is no large-scale underestimation of its prevalence. Even though screening of dialysis patients for Fabry disease might identify patients who remain otherwise unrecognized, screening of high-risk populations for alpha-Gal A deficiency should be carried out with caution since long-term efficacy of treatment is currently unknown.     

Validation of the KDQOL-SFTM: A dialysis-targeted health measure

Background: In evaluations of dialysis therapy, an assessment of health-related quality of life (HRQOL) is often important. The aim of this study was to determine the basic psychometric properties, reliability and validity of the short form of the KDQOL^TM i.e. the KDQOL-SF^TM, a dialysis-targeted instrument, and to assess its ability to detect changes over time. Methods: In a prospective cohort study (Netherlands Cooperative Study on the Adequacy of Dialysis, NECOSAD), all new adult ESRD patients in 32 different Dutch centers were consecutively enrolled. Demographic, clinical and HRQOL data were obtained 3 and 12 months after the start of chronic dialysis therapy. Results: The reliability of the KDQOL-SF^TM was supported by test results that were above the recommended minimal values. Validity of KDQOL-SF^TM was confirmed by the hypothesized positive correlations of the overall health rating and renal function, and by the negative correlations between the number of comorbidities and dialysis dose. Moreover, dialysis-targeted dimensions were more sensitive in detecting relevant differences pertaining to kidney diseases than generic dimensions. The KDQOL-SF^TM was able to detect clinical changes over time. Conclusions: The psychometric properties of the KDQOL-SF^TM were good, and the different dialysis-targeted dimensions were informative with a high reliability and validity. These results support the application of the KDQOL-SF^TM in studies evaluating dialysis therapy.