[Effectiveness of oral supplements of folates, vitamins B12 and B6 in hemodialysed patients. Preliminary results after 5 months of follow-up]. / Efficacia dei supplementi orali di folti, vitamine B12 e B6 in pazienti emodializzati. Risultati preliminari dopo 5 mesi di follow-up.

BACKGROUND: Elevated serum levels of homocysteine have increasingly been associated as a risk factor of cardiovascular disease. Recent reports demonstrated that supplements of folates, vitamin B12 (B12) and vitamin B6 (B6) are effective in correcting serum Hcy levels in hemodialysed patients. AIM: to assess the effectiveness of oral supplements of folates, B12 and B6, in order to reduce serum Hcy levels in our cohort of hemodialysed patients. METHODS: Sixty-one hemodialysed patients have been enrolled in the study (age 68+/-13 years; hemodialysis 62+/-42 months). Oral supplements of calcium folinate (30 mg 3 times a week), B12 (500 mg 3 times a week) and B6 (200 mg 3 times a week) were administered at the end of each hemodialysis session. Serum levels of Hcy, folic acid and B12 were tested at the beginning of the study and at 2 month intervals. RESULTS: After 5 months of follow-up, serum levels of Hcy were normalised in 19% of our patients and in total 70% of them showed a reduction >8% when compared with the basal Hcy levels. No side effects related to folates, B12 or B6 supplementation were observed. CONCLUSIONS: Oral supplements of folates, B12 and B6 are a safe and effective treatment of hyperhomocysteinemia in hemodialysed patients.

GIT (Glucose Infusion Test): polycentric evaluation of a new test for vascular access recirculation.

Introduction. Vascular access recirculation (AR), which is often unacknowledged, remains an important cause of inadequate dialytic dose. The glucose infusion test (GIT) is a new method for detecting and quantifying AR. This paper reports on a polycentric evaluation of the new test and a comparison with the classical Urea-test (UT). Methods. GIT protocol comprises withdrawal from the arterial port (sample A), injection into the venous drip chamber of 1 g glucose in 4 seconds, withdrawal from the arterial port (sample B) continuously from 13 to 17 seconds. Glucose is determined on A and B by a reflectance photometer. If B = A then there is no recirculation. If B exceeds A by at least 20 mg/dl there is recirculation. AR quantification: AR% = (B-A) / 20. GIT was performed on 623 patients from eleven dialysis centers to screen the patients for AR. Subsequently, GIT and Urea-test (UT) were compared in 189 paired tests. The reproducibility of GIT and UT was studied in 28 paired tests performed in sequence. Results. The screening test by GIT was positive in 68 cases (11 %). The majority of positivities was found in central venous catheters (CVC, 27/50 cases, 54 %), whereas only 7 % of artero-venous fistulas (AVF) were positive. In the CVC group, Tesio catheters were more frequently positive compared to Dual Lumen Catheters (64 % vs. 29 %). The comparison GIT - UT showed that results matched in 162 tests (79 negative and 83 positive both by GIT and UT), showing that on the grounds of UT, GIT has high sensitivity and specificity. In 27 tests GIT was positive, but UT negative. This disagreement is due to the different minimal limit of detection, 1 % for GIT and 5% for UT. The reproducibility was greater with GIT than with UT with a lower D% (respectively -0.6 +/- 2.5 and -0.4 +/- 6.1 %, p<0.001) and a lower coefficient of variation (17 vs 33 %). Conclusions. The screening of 623 patients by GIT confirmed that AR in AVF is normally absent, whereas an un-expectedly high frequency of moderate AR in CVC was found. The GIT-UT comparison showed that the new test is simple and immediate, and gives results with higher accuracy, sensitivity and reproducibility than UT.

[Infections from extemporaneous catheters for hemodialysis. Experience in a center]. / Infezione dei cateteri estemporanei per emodialisi. Esperienza di un centro.

BACKGROUND AND AIMS: This study reports a retrospective evaluation of the predominance of infection in 67 dual lumen central venous catheters (CVC), 35 of which were positioned in the femoral vein by the nephrological team and 32 in the subclavian vein by anesthetists. METHODS: The microorganisms responsible for infection, the prevalence of clinically symptomatic infections, the relationship between CVC-correlated infection and the time the catheter remained inserted were evaluated, together with a comparison between the two different insertion sites. RESULTS: Culture tests, performed using Maki's semiquantitative technique, gave positive results in 16/67 (23.8%) cases. The main pathogenic agents found were Staphylococcus epidermidis (37.5%) and Staphylococcus aureus (31.2%). In 3/16 cases (18.78%) infections were clinically symptomatic. The mean permanence of CVC with positive cultures was not statistically different to the mean permanence of CVC with negative cultures (22.44 +/- 13.48 vs 18.38 +/- 17.76). The microorganisms isolated on femoral and subclavian catheters showed a comparable distribution and the prevalence of infection was not statistically different in the two insertion sites. CONCLUSIONS: In conclusion, in the absence of infection, the authors tend to keep working catheters in the site, thus avoiding repeated invasive manoeuvres for replacement and/or repositioning, whereas in the presence of suspected systemic infection they feel it is more prudent to remove the CVC without waiting for the results of the hemoculture, starting first empiric and then specific antibiotic treatment on the basis of the antibiogram.

[Hepatitis C virus and mixed cryoglobulinemia in dialysis]. / Virus dell'epatite C e crioglobulinemia mista in dialisi.

Prevalence of hepatitis C virus (HCV) varies in the dialytic population according to the geographic area (5-85%); the European average is 19%, with marked differences between dialysis units. The means of virus transmission is still not clear and represents one of the major management problems faced by dialysis units. US authors and European study groups have recently demonstrated a high level od HCV infection in patients with essential mixed cryoglobulinemia (EMC), suggesting that the virus plays an etiological role. The authors examined the correlation between mixed cryoglobulinemia and HCV and the possible etiological role of the virus in the pool of patients undergoing dialysis at the Centre. In September 1994 28/63 (44.4%) patients were found to be Ab anti-HCV positive (second and third generation ELISA); circulating cryoglobulins identified as Type II following immunofixation were found in 2/28 patients (7%) using centrifugation and cold incubation techniques. In the absence of the pathologies classically associated with cryoglobulinemia, the patients were diagnoses as suffering EMC. The HCV/EMC correlation in the dialysed population has been analysed in a limited number of studies, with discrepant results (0-47%). This paper highlights the association between HCV and EMC in 7% of chronic dialysed patients and given that the finding of anti-HCV Ab in serum solely documents previous exposure to the virus, we can only indirectly attribute an etiological role to HCV. The search for viral RNA in the serum, cryocrit and surnatant of patients found affected by EMC may provide additional etiopathogenetic information.

Prevalence of hepatitis C infection in a hemodialysis unit.

To define the prevalence of NANB hepatitis, anti-HCV antibodies were determined in 51 patients on renal replacement therapy, in 7 transplanted patients and 17 staff members of the hemodialysis unit. Anti-HCV antibodies were evaluated using immunoenzymatic methods (Ortho HCV ELISA Test System, 1st and 2nd generation). Among hemodialysis patients, seroconversion was respectively documented in 17.6% (9/51) and 52.9% (27/51); none of the transplanted patients were positive with the 1st generation test, while 3/7 were positive with the 2nd. No statistically significant difference was found in the prevalence antibodies between transfused and nontransfused patients. ALT levels were statistically greater in patients with anti-HCV antibodies (X2 2nd generation = 8.83; p less than 0.01). Our results suggest: (1) that hemodialysis represents a risk factor; (2) the validity of substitute markers and (3) more sensitivity of the 2nd than 1st generation test.

[Levels of tumor necrosis factor and interleukin 1 in uremia and in hemodialysis]. / Livelli di tumor necrosis factor ed interleuchina-1 nell'uremia ed in emodialisi.

The present study aimed to assess the serum levels of tumor necrosis factor (TNFalpha) and Interleukin-1 (IL-1) in uremic patients and those patients undergoing extracorporeal replacement therapy in relation to the duration of dialysis and the type of membrane. Serum cytokine values were assayed using an immunoradiometric technique (monoclonal antibodies) in 28 uremic patients and 7 healthy controls. TNFalpha levels were normal in control subjects but increased in uremic patients. Patients undergoing hemodialytic treatment showed increases which were statistically significant in comparison to basal levels, with a trend which was directly correlated to the duration of dialysis. No significant variations were induced by the different types of dialysis membranes used. In virtually all patients IL-1 values could not be assayed using this method.