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Appropriate measurement of the glomerular filtration rate (GFR) is important for the assessment of renal function. This paper reviews the methods used to assess GFR in clinical trials of enzyme replacement therapy (ERT) in patients with Fabry disease, which include inulin clearance, 24-hour creatinine clearance, chromium ethylene diamine tetraacetate ( 5 1 Cr-EDTA) clearance and cystatin C concentrations. GFR has also been estimated using calculations based on creatinine clearance (the Cockcroft-Gault formula) and the Modification of Diet in Renal Disease (MDRD) equation. Analysis of the results of these studies shows that there are striking discrepancies between estimated and measured GFR. For example, the MDRD equation overestimates GFR in patients with Fabry disease who have normal renal function. In addition, cystatin C has been shown to be of limited use for measuring renal function during ERT, because it is influenced by other factors such as age, gender and weight. Conclusion: The use of exact methods, such as inulin clearance, 1 2 4 I-iothalamate, 9 9 mTc-DTPA, 5 1 Cr-EDTA and iohexol, appears to be mandatory for a robust evaluation of the effects of ERT on GFR in patients with Fabry disease.

The emergence of anticardiolipin antibodies in patients with systemic lupus erythematosus is a serious occurrence in regard to a high risk for thrombosis and thromboembolic complications, fetal loss, and renal insufficiency. In an observational analysis, we studied anticardiolipin antibodies during immunoadsorption therapy.We analyzed the magnitude and time course of serum concentrations of the immunoglobulin G (IgG) and IgM subtypes of anticardiolipin antibodies (CIgG and CIgM) along with IgG and IgM, antinuclear antibodies, and antibodies to double-stranded DNA before and after single immunoadsorption sessions and their long-term course in 11 patients with systemic lupus erythematosus.Single immunoadsorption sessions (n = 842) led to a rapid decline in CIgG and CIgM levels by 62.94% +/- 21.60% and 42.02% +/- 22.14%, respectively (P0.0001), along with a corresponding decline in serum levels of antinuclear antibodies (65.04% +/- 18.83%), antibodies to double-stranded DNA (64.67% +/- 21.20%), IgG (58.11% +/- 16.84%), and IgM (32.15% +/- 15.58%). Reduction rates of CIgG and CIgM levels were greater when high initial concentrations (P0.0001) and low IgG levels (P0.0001) were present. Mean reductions in pretreatment values of CIgG and CIgM during 6 months of immunoadsorption therapy were 42.85% +/- 39.94% and 29.39% +/- 70.41% (mean number of sessions/patient = 21.55) and for the 1-year period were 63.20% +/- 22.49% and 58.05% +/- 40.16% (mean number of sessions/patient = 30.46).We observed that immunoadsorption therapy is an effective method to reduce anticardiolipin antibody levels rapidly and keep them at a low level in the long term.

Hauser AC, Lorenz M, Sunder-Plassmann G (University of Vienna, Vienna, Austria). The expanding clinical spectrum of Anderson-Fabry disease: a challenge to diagnosis in the novel era of enzyme replacement therapy (Review). J Intern Med 2004; 255: 629-636. Anderson-Fabry disease is an X-linked recessive lysosomal storage disease resulting from deficient α-galactosidase A activity. The conception of the disease has changed within the last decade. Studies of the last years have shown that the disease is not limited to the classical full-blown manifestation in affected males, which is well known since more than a century, but may also occur in carrier females. The phenomenology may differ in severity and kind of organ manifestation. Cardiac and renal variants with solely disease manifestation of these organs have also been described in an increasing number. It is likely that a spectrum exists regarding α-galactosidase A activity in both genders on the one hand, and an additional one regarding the severity and the number of organs affected on the other. The purpose of this review is to sharpen physicians' perception of this disease. Early and accurate diagnosis is mandatory considering that this disorder is now, after introduction of the novel enzyme replacement therapy, a treatable disease.

Effect of TCN2 776C>G on vitamin B 12 cellular availability in end-stage renal disease patients. Background Transcobalamin II is a serum protein that transports vitamin B 12 from the intestine to the tissues. This complex, holo-transcobalamin II, may reflect vitamin B 12 availability in the body. Conflicting data exist with regard to the effect of a polymorphism in the gene coding for transcobalamin II, TCN2 776C>G, on transcobalamin II levels in the general population, which in turn may affect holo-transcobalamin II, vitamin B 12 , as well as total homocysteine (tHcy) plasma levels. The effect of TCN2 776C>G on vitamin B 12 cellular availability in dialysis patients is unknown. Methods We examined the effect of TCN2 776C>G on holo-transcobalamin II, vitamin B 12 , and tHcy plasma concentrations in 120 dialysis patients. Results Holo-transcobalamin II levels were normal or supranormal in all patients and showed a linear association with albumin ( r = 0.205, P = 0.025) and with vitamin B 12 ( r = 0.778, P = 0.001), but not with age, creatinine, body mass index, tHcy, ln-tHcy, vitamin B 6 , plasma folate, and red blood cell folate concentration. TCN2 776C>G showed no effect on holo-transcobalamin II, vitamin B 12 , and tHcy concentration [one-way analysis of variance (ANOVA), post-hoc Scheffe test]. Multiple linear regression analyses showed that albumin and B 12 are independently associated with holo-transcobalamin II, whereas TCN2 776C>G and MTHFR 677C>T had no effect. Independent predictors of ln-tHcy included creatinine, red blood cell folate, and the MTHFR 677TT genotype. There was also an effect of the TCN2 776CC genotype on ln-tHcy levels in this multivariate analysis, however, that deserves cautious interpretation because there was no effect of TCN2 genotypes by ANOVA and Scheffe test [median ln-tHcy concentrations according to TCN2 genotypes (μmol/L): CC, 3.22; CG, 3.30; GG, 3.23]. Conclusion TCN2 776C>G does not influence holo-transcobalamin II or vitamin B 12 levels, and has no major effect on tHcy concentrations of end-stage renal disease patients.

This study was designed to examine the effect of two single nucleotide polymorphisms in the reduced folate carrier 1 ( RFC1 80G>A) and the glutamate carboxypeptidase 2 ( GCP2 1561C>T) gene on total homocysteine (tHcy) plasma level and folate status in 120 chronic dialysis patients. Red blood cell folate concentration was higher in patients with the GCP2 CT or TT genotype (ANOVA, P = 0.04). Among patient groups with different RFC1 genotypes, red blood cell folate level was not significantly different. A multivariate analysis confirmed that the GCP2 1561C>T genotype ( P = 0.011) had a significant influence on the red blood cell folate concentration. Overall, serum folate, creatinine, and the GCP2 polymorphism explained nearly 50% of the variance of red blood cell folate. A linear multivariate regression analysis showed that red blood cell folate ( P P MTHFR ) 677T allele ( P = 0.013) are independent predictors of tHcy plasma level explaining 49% of the variance of tHcy plasma concentration. GCP2 1561C>T and RFC1 80G>A showed no effect on tHcy and folate plasma level. In conclusion, GCP2 1561C>T, but not RFC1 80G>A, is a predictor of red blood cell folate level in chronic dialysis patients. Both polymorphisms have no major effect on tHcy plasma concentration in end-stage renal disease patients. E-mail: Gere.Sunder-Plassmann@univie.ac.at

1. Blood leptin levels are increased in obese subjects and seem to play a major role in the hypothalamic regulation of appetite and energy expenditure. 2. We measured plasma leptin levels in a cohort of 46 patients on maintenance haemodialysis treatment and 26 control subjects. 3. Higher body mass indices were associated with higher plasma leptin levels in both groups. 4. The increase was more pronounced in the dialysis group than in the control group (P = 0.001), leading to inappropriately high plasma levels. 5. Haemodialysis with low flux cellulosic dialysers did not result in a decrease in plasma levels, while dialysis with high flux dialysers and haemodiafiltration led to a substantial reduction of the initial value to 76.95 ± 14.89% (P = 0.013) and 62.90 ± 24.94% (P = 0.001) respectively. 6. Our data suggest that high flux dialysis membranes can decrease plasma leptin levels and that inappropriately high plasma leptin levels may play a role in the nutrition of haemodialysis patients.

Purpose: Anderson-Fabry disease is an inherited lysosomal storage disease with a broad and unspecific range of symptoms, a painful course of disease and early death. The recent development of new enzyme therapy emphasises the need for early diagnosis and treatment of undiagnosed patients. One of the affected organs of Anderson-Fabry disease is the eye. Cornea verticillata – corneal opacities and corneal dystrophy – as well as tortuositas vasorum can occur in an early stage of the disease affecting almost all hemizygous men and more than 70% of heterozygous women. In order to identify unknown cases with Anderson-Fabry disease, we carried out a screening programme contacting Austrian ophthalmologists. Methods: All 658 Austrian ophthalmologists were asked to record patients with cornea verticillata as well as tortuositas vasorum – twice at an interval of 3 months. Results: 33% of the contacted ophthalmologists replied, identifying 5 patients suspected of having Anderson-Fabry disease. After additional examinations including tests for enzyme activities Anderson-Fabry disease was confirmed in 1 man. Conclusion: We have identified 1 case with Anderson-Fabry disease through our ophthalmology screening programme among a population of approximately of 8 million. Ophthalmologic screening programmes for ocular manifestations typical of Anderson-Fabry disease are limited because of the moderate visual affection in these patients. Nevertheless, considering the limited options to detect such cases otherwise, ophthalmologists have a major responsibility to identify patients with Anderson-Fabry disease on routine examinations.

Anderson-Fabry disease is a multisystemic lysosomal storage disorder due to a deficiency of α-galactosidase A resulting in an accumulation of neutral glycosphingolipids. Due to its rare occurrence the disease is often misdiagnosed or the correct diagnose is delayed for many years (Weidemann et al. 2008). Dermatologists except ophthalmologists play the most important role for early diagnosis of this disorder, which can now be treated by enzyme replacement therapy. Otherwise, Anderson-Fabry disease is a lethal disorder, renal disease or stroke being the most important causes of death (Grunfeld et al. 2002, Desnick et al. 2003). Early diagnosis and treatment is essential to limit organ damage (Hauser et al. 2004b, Branton et al. 2002).

1. The generation of the plasma SC5b—9 complex (the soluble form of the membrane attack complex) during haemodialysis was studied in 29 patients together with markers of the classical (C4d fragment) and alternative (Bb fragment) pathways and the common iC3b fragment. 2. In the patients dialysed with Hemophan and Cuprophan membranes, a rapid increase in the plasma levels of SC5b—9 complex, Bb fragment and iC3b fragment occurred within 15 min of the initiation of the haemodialysis procedure. The SC5b—9 complex and the Bb fragment concentrations remained at a plateau until 120 min thereafter. The iC3b fragment level showed a continual decline. 3. The C4d fragment concentrations remained unchanged, indicating that generation of the membrane attack complex is most likely due only to activation of the alternative pathway. 4. The generation of the membrane attack complex occurred throughout the full haemodialysis period. In patients treated with Polysulfon membranes no statistically significant variation in these components was noted. 5. The study shows that the membrane attack complex may be generated during the full period of the haemodialysis session and is a stable index of biocompatibility. 6. Moreover, it seems be involved directly in haemodialysis-associated phenomena.

Anderson-Fabry disease is possibly underdiagnosed in patients with end-stage renal disease. Nationwide screening was therefore undertaken for Anderson-Fabry disease among dialysis patients in Austria. Screening for alpha-galactosidase A (AGAL) deficiency was performed by a blood spot test. In patients with a positive screening test, AGAL activity in leukocytes was determined. Individuals with decreased leukocyte AGAL activity were subjected to mutation testing in the GLA gene. Fifty (90.9%) of 55 Austrian hemodialysis centers participated in this study; 2480 dialysis patients (80.1% of the Austrian dialysis population) were screened. In 85 patients, the screening test was positive (85 of 2480, 3.42%; women, 3.32%; men, 3.50%). Among these 85 patients, 4 men (in 3 of whom Anderson-Fabry disease was already known before screening) had a severely decreased and 11 subjects had a borderline low AGAL activity. Genetic testing revealed mutations associated with Fabry disease in all four men with severely decreased AGAL activity resulting in a prevalence of 0.161% for the entire study population. A nationwide screening of dialysis patients permitted detection of a hitherto unknown man with Anderson-Fabry disease. The overall prevalence among dialysis patients was at least ten times higher as compared with recent registry data. Screening programs among patients with end-stage renal disease, especially men, should be put in place to identify families with Anderson-Fabry disease who probably may benefit from specific clinical care, and perhaps from enzyme replacement therapy. In dialysis patients, however, there is no evidence to support enzyme replacement therapy at present.

The effectiveness of intravenous folinic acid or intravenous folic acid for the treatment of hyperhomocysteinemia of hemodialysis patients is unknown. In a randomized, controlled, double-blind trial, 66 hemodialysis patients were administered either 15 mg of folic acid or an equimolar amount (16.1 mg) of folinic acid intravenously three times weekly. Normalization of total homocysteine (tHcy) plasma levels after 4 weeks of treatment was achieved in 10 patients (30.3%) in the folic-acid group and 6 patients (18.2%; P: = 0.389) in the folinic-acid group (normalization at any time during the study period in 39.4% and 33.3% of the patients; P: = 0.798). The relative reduction in tHcy plasma levels at week 4 was 32.2% in the folic-acid group and 34.1% in the folinic-acid group. A high baseline tHcy plasma concentration (P: = 0.00001), methylenetetrahydrofolate reductase (MTHFR) 677TT/1298AA genotype (P: = 0.03540), and low red blood cell folate concentrations (P: = 0.02285) were associated with a better relative response to treatment. Normalization of tHcy plasma levels was dependent on a lower baseline tHcy level (P: = 0.01976), younger age (P: = 0.00896), and MTHFR 677TT/1298AA or 677CT/1298AC genotypes (P: = 0.00208 and P: = 0.02320, respectively). A 4-week course of intravenous folinic acid is not superior to intravenous folic acid in reducing elevated tHcy plasma levels in hemodialysis patients. The response to treatment is predicted by tHcy plasma level, red blood cell folate content, and MTHFR genotype.

The prevalence of pulmonary thromboembolism at autopsy was assessed in a retrospective study of a cohort of 185 patients undergoing maintenance hemodialysis treatment who died in the last decade. The overall frequency of thromboembolism was 12.43% in the dialysis population, which statistically was significantly less than in a control group of 8,051 nondialysis patients (21.77%; P = 0.0023). Moreover, pulmonary thromboembolism was less frequently fatal or contributing to death in the dialysis group than in the control group (P = 0.039). The prevalence of pulmonary thromboembolism in the dialysis group remained statistically unchanged over the 10-year period and was independent of a steady increase in the percentage of patients receiving recombinant erythropoietin therapy and the average hematocrit values. The occurrence of preterminal pulmonary thromboembolism was associated with a shorter period since onset of hemodialysis treatment and with infection as cause of death (P = 0. 031; P = 0.029, respectively). No statistically significant influence of the type of basic renal disease, type of dialysis anticoagulation, or dialysis access could be found. Our data suggest that, at least in the preterminal stage, the introduction of recombinant erythropoietin within the last decade had no substantial influence on the prevalence of pulmonary thromboembolism.

Twenty-three patients with analgesic nephropathy and apparent cessation of drug abuse were tested for blood acetaminophen and salicylate on the occasion of routine renal control examinations. In 12 patients (mean creatinine level 2.74 +/- 1.09 mg/dl) no deterioration of renal function was noted within a 1-year observation period (Group 1). In 11 patients a significant progression of renal insufficiency was observed (mean creatinine level rose from 3.86 +/- 1.06 to 6.40 +/- 3.18 mg/dl within the same observation period; Group 2). Blood tests for acetaminophen and salicylate were positive in 2 patients of Group 1 and in 9 patients of Group 2 (chi 2 = 7.326), p less than 0.01). Our data emphasize the importance of a continuous analgesic abuse hidden from the medical staff with regard to the progression of renal insufficiency in analgesic nephropathy.

Decreased postheparin lipolytic activity in renal transplant recipients with cyclosporin A. The patterns of hyperlipidemia in renal transplant recipients (RTRs) are more variable than in the uremic state, showing increases in both very low-density lipoprotein (VLDL) and low density lipoprotein (LDL). This has been attributed, at least in part, to immunosuppressive therapy, especially to treatment with corticosteroids. Postheparin lipolytic activity (PHLA) was determined in 28 RTRs. Sixteen patients presenting with hyperlipidemia comprised group A, who were aged 49.8 ± 13.5 years, and had a cholesterol of 8.24 ± 1.86 mmol/liter, triglycerides of 6.02 ± 3.33 mmol/liter. Twelve patients presenting cholesterol and triglyceride values within the normal range were in group B, and were aged 48.6 ± 13.3 years. All RTRs received cyclosporin A (CsA) twice daily orally, which were divided in two equal doses and adjusted to provide CsA blood trough levels (RIA) in a range of 250 to 350 ng/ml. Twenty-one RTRs were additionally treated by alternate-day corticosteroids, whereas seven patients had CsA on their sole immunosuppressive agent. PHLA (µmol free fatty acids/ml/hr, given 10 and 20 min after 100 U/heparin kg body wt intravenously) was commonly reduced in RTRs (group A at 10/20 min: 5.6 ± 1.1/5.26 ± 1.2; group B: 8.26 ± 2.91/8.38 ± 3.44) as compared to the values obtained in healthy controls (15.3 ± 2.9/17.2 ± 5.0). This was mainly due to a reduction of the activity of the hepatic triglyceride lipase, and to a minor extent to a reduced activity of peripheral lipoprotein lipase. There was no statistically significant difference of PHLA in RTRs with or without corticosteroid treatment. Postheparin lipolytic activity is commonly decreased in renal transplant recipients. This effect does not depend on low corticosteroid administration, but may be caused by CsA medication.

In 6 male subjects the diurnal variation of urinary oxalic acid excretion was studied after ingestion of chocolate, a food stuff rich in oxalic acid. The ingestion of chocolate caused a striking but transient increase in urinary oxalic acid excretion due to its absorption in the upper gastrointestinal tract. The peak excretion rates occurred 2-4 h after the intake of the chocolate. The peak values were 235% of the fasting excretion rate in the trial with 50 g chocolate and 289% in the trial with 100 g chocolate and reached the amounts found in cases with primary hyperoxaluria. The administration of ranitidine had no influence on oxalic acid absorption. The transient hyperoxaluria observed seems to be an important factor for the formation of calcium oxalate calculi in patients on risk for stone disorders.