Ionized calcium/total calcium ratio during biofiltration.

The transmembrane transfer of calcium during hemodialysis is related to many factors (calcium gradient, plasma volume flow, plasma concentration of phosphate). During biofiltration the high ultrafiltration rate reduces the net transfer of calcium from dialysate to patient. Prolonged metabolic alkalosis occurs during biofiltration, lowering the ionized calcium/total calcium ratio. These two factors may stimulate PTH secretion, with negative long-term effects in dialysis bone disease.

Puglia cooperative study on biofiltration.

Biofiltration (BF) was performed on 60 patients from 12 dialytic centers in Puglia. The protocol was 9-10.5 hours a week with 1.2 m2 PAN dialyzers. A dialysate with 140 Na+, 2-2.5 K+, 3.5-4 Ca++, 38 mEq/l acetate was used in 49 patients; the acetate was replaced by bicarbonate (35-40 mEq/l) in 11 patients. The same patients were treated for 1 year with standard acetate dialysis (49 patients) and standard bicarbonate dialysis (11 patients). The two protocols were compared on the basis of the clinical state, BUN and serum creatinine, acid-base balance, PTH, anemia, and nerve conduction velocity (NCV). Favourable effects were achieved in 55 patients. Four patients left the program because of progressive hyperhydration. BUN and serum creatinine levels showed a moderate, but insignificant increase. PTH, anemia and NCV did not worsen. BF gave better correction of metabolic acidosis in the patients undergoing acetate dialysis.

Influence of phosphatidylcholine on ultrafiltration and solute transfer in CAPD patients.

Fifteen patients (mean age 59.9 +/- 16.1 years) treated by CAPD for a mean of 21.6 +/- 14 months, underwent peritoneal clearances before and after 15 days of intraperitoneal phosphatidylcholine (PC) treatment (50 mg/L). No difference was observed in urea, creatinine, uric acid, and reverse dextrose clearances. A statistically significant increase in phosphate clearances (4 and 6 hr dwell times) (1.36%) and a reduction in drainage volume (2 hr dwell time) (1.36%) were observed after treatment. Urine output and percent dextrose reabsorption were unchanged. The ultrafiltration (UF) showed a tendency to increase, which lasted for 15 days after discontinuation of treatment. This tendency allowed the patients to reduce, during the same period, the amount of hypertonic solution (23.8 L vs. 21.3 L) required. The tendency to increase UF over time deserves further study.

Follow-up of reverse dextrose clearances in patients undergoing CAPD.

Three hundred eighty-eight sequential reverse dextrose clearances (RDC) have been performed in 61 unselected patients (12 of whom were diabetics), whose mean age was 54 years (30-79). They were treated for a mean time of 23 +/- 12 months (0-60); the total observation time was 1,440 months. One hundred forty-two episodes of peritonitis were registered, producing a peritonitis incidence of 1 episode per 10.2 patient months. The RDC values are significantly inversely related to dwell-time and show a tendency to increase over time; they never, however, reach statistical significance. Age of patients, episodes of peritonitis and primary renal disease (diabetes) had no influence. It is important to underline the significant inverse relationship between ultrafiltration and residual diuresis. Unknown mechanisms regulate this relationship.

Hepatitis C virus infection in four haemodialysis units of southern Italy: epidemiological report.

UNLABELLED: The haemodialysis patients are an high risk population for hepatitis viral infections. While the incidence of HBV has decreased worldwide, HCV is now the major cause of viral infection in these patients. The aim of our study was to define a complete map of patients undergoing routine replacement therapy by haemodialysis in the province of Foggia, Southern Italy, who were HCV Ab positive, the presence of viraemia and their genotypes; moreover, we investigated the probable factors involved in determining the infection as well as the means of prevention. MATERIALS AND METHODS: We enrolled 330 patients treated in four haemodialysis centres (DC) and six secondary units; mean age was 57 years and mean duration of dialysis 76 months. Samples were drawn to determine cytolysis indexes and the HCV Ab status; in HCV positive patients, we also looked for viraemia and HCV genotypes. Data were analysed by a transversal cross-section study. RESULTS AND CONCLUSIONS: Prevalence of HCV infection was 0.43 (males 0.45, females 0.42). The risk of contracting the infection was shown to be significantly different in the various DCs and did not seem to be related to the severity of the preventive measures. There was no significant difference between the various DCs in the comparison between the odds of HCV-RNA+ and HCV-RNA- patients. No significant prevalence of a given genotype emerged from a cross-sectional study related to the comparison between different genotypes. Moreover, transfusions of blood products seemed to have no significant relation to HCV infection. Finally, patients treated with haemodialysis for more than 36 months run a seven time greater risk of contracting HCV infection.

Polymorphism of the angiotensin-converting enzyme gene in end-stage renal failure patients.

The plasma levels of angiotensin-converting enzyme (ACE) are modulated by the insertion (I)/deletion (D) polymorphism within the ACE gene locus. An association between progressive renal disease, raised cardiovascular risk, and ACE plasma levels has been shown. To evaluate the genotype frequencies of the I/D polymorphism in terminal renal failure, we have enrolled 341 dialysis patients (321 on hemodialysis and 20 on peritoneal dialysis) in a district of southern Italy (Foggia). As controls, 1,307 subjects from the same area have been enrolled. Genomic DNA was obtained from leukocytes, and the ACE I/D polymorphism was determined by polymerase chain reaction. Among uremics, 151 subjects (44.3%) carried the DD genotype, 149 (43.7%) the ID, and 41 (12.0%) the II genotype. In controls, 560 subjects (42.8%) had the DD genotype, 577 (44.1%) the ID, and 170 (13.1%) the II genotype (p = n.s.). Among patients, the frequency of DD subjects was higher in men (48.3%) than in women (39. 7%, p < 0.01). A slight different frequency of the DD genotype was found according to the duration of dialysis treatment: 47.5% in patients on dialysis up to 60 months and 41.7 and 40.6% in those with a dialytic age of 60-120 and >120 months, respectively (p for trend: 0.53). Patients with or without cardiovascular diseases, such as hypertension, left ventricular hypertrophy, coronary artery disease, and chronic cardiac failure, did not exhibit any difference in ACE I/D allele and genotype frequencies (p always >0.05). In conclusion, frequencies of the ACE DD genotype were similar in uremics and in controls and did not differ between patients with and without cardiovascular diseases. A nonsignificant inverse relationship with the time spent on dialysis was observed, suggesting that ACE I/D polymorphism may influence the cardiovascular death rate.