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R Maiorca

Publications and source records attributed to R Maiorca.

At least 37 records · Page 2Linked to original sources
PubMed1998

Correction of metabolic acidosis increases serum albumin concentrations and decreases kinetically evaluated protein intake in haemodialysis patients: a prospective study.

BACKGROUND: Metabolic acidosis in haemodialysis (HD) patients increases whole body protein degradation while the correction of acidosis reduces it. However, the effects of the correction of acidosis on nutrition have not been clearly demonstrated. STUDY DESIGN: In this study we have evaluated the effects of 3 months of correction of metabolic acidosis by oral sodium bicarbonate supplementation on protein catabolic rate (PCRn) and serum albumin concentrations in 12 uraemic patients on maintenance HD for at least 6 months (median 49 months; range 6-243 months). Pre-dialysis serum bicarbonate, arterial pH, serum albumin, total serum proteins, serum creatinine, plasma sodium, haemoglobin, PCRn, Kt/V, and TACurea, were evaluated before and after correction. RESULTS: Serum bicarbonate levels and arterial pH increased respectively from 19.3 +/- 0.6 mmol/l to 24.4 +/- 1.2 mmol/l (P < 0.0001) and 7.34 +/- 0.03 to 7.40 +/- 0.02 (P < 0.0001). Serum albumin increased from 34.9 +/- 2.1 g/l to 37.9 +/- 2.9 g/l (P < 0.01), while PCRn decreased from 1.11 +/- 0.17 g/kg/day to 1.03 +/- 0.17 g/kg/day (P < 0.001). No changes in Kt/V, total serum proteins, serum creatinine, plasma sodium, haemoglobin, body weight, pre dialysis systolic and diastolic blood pressure, and intradialytic weight loss were observed. CONCLUSIONS: Our data demonstrate that correction of metabolic acidosis improves serum albumin concentrations in HD patients. The correction of acidosis induces a decrease in PCRn values, as evaluated by kinetic criteria, suggesting that in the presence of moderate to severe acidosis this parameter does not reflect the real dietary protein intake of the patients probably as a result of increased catabolism of endogenous proteins. The correction of metabolic acidosis should be considered of paramount importance in HD patients.

Acidosis↗
PubMed1997

Blood volume changes during three different profiles of dialysate sodium variation with similar intradialytic sodium balances in chronic hemodialyzed patients.

The aim of this study was to evaluate the effects on blood volume (BV) preservation of three different profiles of dialysate sodium variation with similar intradialytic sodium balances. Ten uremic patients aged 50 +/- 11 years receiving regular bicarbonate hemodialysis for 49 +/- 57 months were studied. Each patient underwent three hemodialysis treatments with different modalities of dialysate sodium profiles: constant sodium hemodialysis (CHD), high-low sodium hemodialysis (H-LHD), and low-high sodium hemodialysis (L-HHD). In CHD, the dialysate sodium concentration was 141 mEq/L and did not change during treatment. In H-LHD and L-HHD, the dialysate sodium concentration at the start of dialysis was 160 mEq/L and 133 mEq/L, respectively, and remained constant for 60 minutes. At this time, a single-step break point of variation of dialysate sodium concentration occurred. The dialysate sodium concentration changed according to a model aimed to keep identical the amount of dialysate sodium exchanged in the three different dialysis procedures. The duration of hemodialysis, the blood flow rate, the dialysate flow rate, and the dialysis membrane were the same for all three different hemodialysis modalities. The ultrafiltration rate was kept constant during treatment. Total dialysate collection and intradialytic sodium balance were calculated for each hemodialysis session. Blood pressure and heart rate were monitored at 10-minute intervals; percent reductions of BV (%R-BV) were continuously monitored by an online optical reflection method (Hemoscan; Hospal-Dasco, Medolla, Italy). The results have shown a lower intradialytic %R-BV with H-LHD compared with L-HHD and CHD. No differences in total ultrafiltration rate, systolic and diastolic blood pressures, and heart rate were observed among the three different dialysis procedures. The total dialysate sodium collected and the intradialytic sodium balances were very similar among the three different dialysis procedures, confirming the accuracy of the precision of the sodium model used. The H-LHD sodium profile may be a useful tool in the prevention of excessive %R-BV and of dialysis intolerance episodes.

Adult↗
PubMed1997

A large TSC2 and PKD1 gene deletion is associated with renal and extrarenal signs of autosomal dominant polycystic kidney disease.

BACKGROUND: The renal lesions in tuberous sclerosis complex (TSC) consist in multiple angiomyolipomas, often associated with cysts of variable size. Recently a few TSC patients with early-onset renal cysts resembling the autosomal dominant polycystic kidney disease (ADPKD) have been described. Virtually all of them showed deletions of both TSC2 and PKD1 genes. METHODS: Two unrelated families in which TSC and PKD co-segregate were investigate. 16p13.3-linked haplotype segregation, Southern blot, pulsed field gel electrophoresis, and loss of heterozygosity analyses were performed in both affected and unaffected family members. RESULTS: The proband from family 1 was first recognized as presenting typical neurological signs and skin lesions of TSC and multiple renal cysts at 12 years of age. Haemodialysis became necessary at age 28. CT and MRI scans revealed multiple cysts in the live and an asymptomatic, 3-4 mm aneurysm of the middle cerebral artery. His mother, who died at 47 of breast cancer, had ADPKD and reached the ESRD at 42. She showed facial angiofibromas. Both patients carried a submicroscopic germline deletion spanning the entire TSC2 gene and the large majority of PKD1 coding sequence. In the proband from family 2, the TSC diagnosis was made at 4 years. Enlarged polycystic kidneys causing and-stage renal failure at 19 years were observed. This patient carried a large germline, de novo deletion involving the entire TSC2 and PKD1 genes. In addition we could show in a renal hamartoma from this subject the loss of heterozygosity of markers spanning the TSC2 and PKD1 genes from the residual, normal chromosome 16 of paternal origin. CONCLUSIONS: The presence of a deletion involving both TSC2 and PKD1 genes should be considered in the clinical assessment of TSC children with an early-onset polycystic kidney disease, and more generally in all ADPKD patients who develop end-stage renal failure prior to the fourth or fifth decade of life. Finally, the occurrence of typical renal and extrarenal signs of ADPKD in a PKD1 hemizygote individual seems to support concept that a somatic inactivation of the residual PKD1 gene is required for the development of the cysts.

Adult↗
PubMed1996

A prospective comparison of bicarbonate dialysis, hemodiafiltration, and acetate-free biofiltration in the elderly.

Hemodiafiltration (HDF) and more recently acetate-free biofiltration (AFB) have shown good blood purification and cardiovascular stability in young and middle-aged hemodialysis patients. It is not clear if this is also valid for elderly patients. Twelve patients aged more than 70 years (mean age +/- SD, 76 +/- 4 years) on regular dialysis for at least 5 months were treated with bicarbonate dialysis (BD), HDF, or AFB in a randomized sequence and prospectively followed for 6 months (72 dialysis sessions/patient) for each procedure. The dialysis solution (containing bicarbonate), blood flow rate, and dialysate flow rate were the same with all the methods. During HDF and AFB solutions containing bicarbonate at a concentration of 27 to 30 mEq/L and 145 mEq/L, respectively, were infused postdilution at a rate of 66 +/- 7 mL/min and 2.81 +/- 0.12 L/hr, respectively. During the period of observation we evaluated the number of intradialytic hypotensions, the episodes of nausea, vomiting, headache (dialysis intolerance), body weight, the interdialysis weight gain, the duration of the dialysis session, the number of hospitalizations/patient, and the length of hospitalization/patient. At the end of each observation period we determined: Kt/V, protein catabolic rate, acid base balance, serum creatinine, serum calcium, serum phosphorus, alkaline phosphatases, and serum intact parathyroid hormone. After the switch from BD to either HDF or AFB, the results have shown a significant reduction of dialysis hypotension episodes (18 percent on BD, 14 percent on HDF, and 13 percent on AFB; BD v HDF, P = 0.001; BD v AFB, P = 0.0001; and HDF v AFB, P = NS) and of dialysis intolerance (3.3 percent on BD, 1.3 percent on HDF, and 1.1 percent on AFB; BD v HDF, P = 0.021; BD v AFB, P = 0.019; and HDF v AFB, P = NS). Kt/V improved significantly after the switch from BD to either HDF or AFB (1.17 +/- 0.06 on BD, 1.32 +/- 0.12 on HDF, and 1.32 +/- 0.13 on AFB; BD v HDF, P = 0.021; BD v AFB, P = 0.003; HDF v AFB, P = NS). Protein catabolic rate also improved in HDF and AFB compared with BD (0.90 +/- 0.12 on BD, 1.03 +/- 0.15 on HDF, and 1.04 +/- 0.14 on AFB; BD v HDF, P = 0.001; BD v AFB, P = 0.009; and HDF v AFB, P = NS). AFB showed a better correction of acidosis compared either with BD or HDF (serum bicarbonate, 20.3 +/- 1.1 mEq/L on BD, 20.8 +/- 2.2 mEqL on HDF, and 22.2 +/- 2.4 mEq/L on AFB; BD v HDF, P = NS; BD v AFB, P = 0.01; and HDF v AFB, P = 0.030). The other parameters observed did not differ. In conclusion HDF and AFB show a better dialysis efficiency and a better hemodynamic tolerance compared with BD. This fact is associated with an improvement in protein intake as assessed by kinetic criteria. Acetate-free biofiltration has the further advantage of a better control of the acid-base balance compared with BD and HDF. HDF and AFB are useful dialytic options to traditional BD hemodialysis even in patients older than 70 years.

Aged↗
PubMed1996

Differing dialysis treatment strategies and outcome.

The choice of a dialysis treatment depends on many factors, both medical and non-medical. A full and rational treatment requires easy access to a transplantation programme and to all dialysis modalities, extracorporeal or peritoneal. Presently, haemodialysis (HD) is used almost exclusively for in-centre or limited care treatment, peritoneal dialysis (PD) being preferred for home treatment. On HD, bicarbonate buffer is used in preference to acetate. Mixed convective-diffusive HD techniques have a very limited utilization world-wide because of their cost. Use of PD and automated PD continues to grow, although slowly. In our single-centre experience on a large number of patients, 10-year patient survival is not different on CAPD and HD, and there is initial lower risk of death on CAPD for patients > or = 75 years of age. Drop-out from CAPD has increased in recent years, mainly due to the patient/partner 'burn-out'. Drop-out is less for the elderly, and the difference in modality change between CAPD and HD decreases with increasing patient age, suggesting a clear indication for CAPD in the elderly, or in adults waiting for a transplant. The clinical background, e.g. the presence of diabetes mellitus, cardiovascular disease, dyslipidaemia or obesity, is also important in the choice of method.

Adult↗