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Biomedical subjects

V Bellizzi

Publications and source records attributed to V Bellizzi.

At least 19 recordsLinked to original sources
PubMed2006

Very low protein diet supplemented with ketoanalogs improves blood pressure control in chronic kidney disease.

Blood pressure (BP) is hardly controlled in chronic kidney disease (CKD). We compared the effect of very low protein diet (VLPD) supplemented with ketoanalogs of essential amino acids (0.35 g/kg/day), low protein diet (LPD, 0.60 g/kg/day), and free diet (FD) on BP in patients with CKD stages 4 and 5. Vegetable proteins were higher in VLPD (66%) than in LPD (48%). LPD was prescribed to 110 consecutive patients; after run-in, they were invited to start VLPD. Thirty subjects accepted; 57 decided to continue LPD; 23 refused either diet (FD group). At baseline, protein intake (g/kg/day) was 0.79+/-0.09 in VLPD, 0.78+/-0.11 in LPD, and 1.11+/-0.18 in FD (P<0.0001). After 6 months, protein intake was lower in VLPD than LPD and FD (0.54+/-0.11, 0.78+/-0.10, and 1.04+/-0.21 g/kg/day, respectively; P<0.0001). BP diminished only in VLPD, from 143+/-19/84+/-10 to 128+/-16/78+/-7 mm Hg (P<0.0001), despite reduction of antihypertensive drugs (from 2.6+/-1.1 to 1.8+/-1.2; P<0.001). Urinary urea excretion directly correlated with urinary sodium excretion, which diminished in VLPD (from 181+/-32 to 131+/-36 mEq/day; P<0.001). At multiple regression analysis (R2=0.270, P<0.0001), BP results independently related to urinary sodium excretion (P=0.023) and VLPD prescription (P=0.003), but not to the level of protein intake. Thus, in moderate to advanced CKD, VLPD has an antihypertensive effect likely due to reduction of salt intake, type of proteins, and ketoanalogs supplementation, independent of actual protein intake.

Aged↗
PubMed2003

The prediction of single-frequency BIA variables from individual characteristics.

To define whether reference values for bioimpedance analysis (BIA) can be predicted in healthy individuals, individual characteristics and BIA variables (resistance index=height(2)/parallel resistance and reactance index= height(2)/parallel reactance) were evaluated in non-obese healthy individuals: 863 men and 769 women with an age range 20-70 years and body mass index (BMI) 19.0-29.9 kg/m(2). The following predictive equations were obtained using multiple regression analysis:Resistance index (cm(2)/ohm)Males 21.06 + 0.087xage + 1.091xweight -1.801xBMI,Females 20.35 + 0.037xage + 0.878xweight - 1.343xBMIReactance index (cm(2)/ohm)Males 0.57 + 0.117xweight - 0.096xBMIFemales 1.42 + 0.078xweight - 0.075xBMIIn conclusion, reference BIA values seem to be reasonably predicted based on individual characteristics.

Adult↗
PubMed2001

Abnormalities of bioimpedance measures in overweight and obese hemodialyzed patients.

BACKGROUND: The body composition in overweight and obese hemodialyzed patients (HD) remains ill-defined. This study evaluates in HD patients the influence of body size, as indicated by body mass index (BMI, kg/m(2)), on body composition by measuring bioimpedance analysis (BIA)-derived variables (phase angle (PA), fat-free mass (FFM) and body cell mass (BCM). METHODS: We studied 50 Caucasian patients (mean age 62.8+/-9.2 y) on standard bicarbonate hemodialysis for at least 12 months who regularly achieved dry weight in post-HD, received similar dialysis doses and were free from inflammation/infection. Thirty-eight gender- and age-matched healthy subjects were included as controls (CON). Both HD and CON were divided into three groups on the basis of their BMI(kg/m2) 18.5-24.9, normal-weight (NW); 25-29.9, overweight (OW); and > or =30, obese (OB). In HD patients, BIA was performed 30 min after the end of dialysis. RESULTS: Seven patients were obese (12%) while 16 were overweight (32%); in CON, 12 were obese (31%) and 12 overweight (31%). BIA-measured extracellular water was comparable in all groups. PA, which was similar in normal-weight HD and CON (6.2+/-0.9 degrees and 6.3+/-0.8 degrees ), decreased in OW- and OB-HD patients (5.3+/-1.0 degrees and 5.2+/-0.6 degrees, respectively; P<0.05 vs NW-HD) while it was unchanged in OW- and OB-CON (6.1+/-0.8 degrees and 5.9+/-0.5 degrees, P<0.05 vs respective HD groups). In OW and OB patients, the lower PA values were coupled with a major reduction of BIA-derived percentage BCM and FFM (P<0.05 vs NW-HD, and vs OW- and OB-CON). In patients, PA and BCM correlated with anthropometry-measured FFM. Of note, serum albumin and protein catabolic rate were significantly reduced in OB patients. CONCLUSION: In overweight and obese HD patients, BIA-derived FFM, BCM and PA are significantly lower with respect to normal-weight patients and BMI-matched controls. These abnormalities of body composition are coupled with reduction of anthropometric measures of lean mass and a decrease of protein intake that, however, becomes significant only in the obese. We therefore suggest that overweight and obese HD patients are at risk of protein malnutrition in spite of excessive energy intake. BIA may be considered as a useful diagnostic tool to detect such a condition early.

Body Composition↗
PubMed2001

Successful use of central venous catheter as permanent hemodialysis access: 84-month follow-Up in lucania.

Cuffed tunneled venous access catheters are commonly used for temporary and permanent access in hemodialysis (HD) patients. These catheters serve an essential role in providing permanent access in subjects in whom all other access options have been exhausted. The predominant complications are catheter thrombosis, catheter fibrin sheating and infection. The aim of this study was to evaluate long-term survival and complications of permanent venous catheters (PVC) placed for the purpose of HD during the period from January 1992 to December 1998, at the Dialysis Units of Lucania (a southern Italian region). A total of 98 PVC were placed in 88 patients during this period. The catheters used were of three types: (a) 72 VasCath Soft Cell catheters (Bard Instrument Company, Toronto, Ont., Canada); (b) 22 PermCath catheters (Quinton Instrument Company, Seattle, Wash., USA), and (c) 4 Tesio catheters (Bellco SpA, Mirandola, Italy). Survival curves of catheters were calculated using the Kaplan-Meier product-limit estimator. The patient survival was 60% at the 78th month. Actually, 52 patients (27 males, 25 females) are still alive: 15 (26.9%) of these patients have diabetes mellitus and 1 has been transplanted. The actuarial survival rate of PVC was 89% in the whole population studied and 82% in subjects alive after 84 months. Twenty-five patients (28.4%) had PVC as the first reliable vascular access. Long-term complications occurred 27 times (1 episode every 44.81 month/patient) as: breakage (3.1%); thrombosis (10.2%); displacement (2.0%); subcutaneous tunnel bleeding (3.1%); inadequate blood flow (7.1%), and infection (10.2%). In conclusion, our data confirm that PVC might represent an effective long-term blood access route for HD. Again, PVC are getting the access of choice for selected patients (i.e., older subjects with cardiovascular diseases and cancer patients) and are enjoying a dramatic increase in use for subjects who are terrified of repetitive venopuncture.

Actuarial Analysis↗
PubMed1999

Randomized, double-blind, placebo-controlled study of arginine supplementation in chronic renal failure.

BACKGROUND: Supplementation with L-arginine (ARG) strikingly ameliorates proteinuria and glomerulosclerosis in remnant rats by overcoming nitric oxide (NO) deficiency. Whether or not the same holds true in humans is unknown. This study aimed at evaluating the effects of ARG on the NO system and renal function in proteinuric patients with moderate chronic renal failure (CRF). METHODS: We measured plasma arginine, urinary and plasma NO3 (an index of NO synthesis), and urinary cGMP (an intracellular mediator of NO), as well as proteinuria and renal functional reserve (RFR) in CRF patients orally treated for six months with either ARG (0.2 g/kg body wt/day, CRF-A group) or the control vehicle (CRF-C). Normal subjects (NOR) were also included for basal comparisons. RESULTS: In CRF patients at baseline, plasma arginine was within the normal range; similarly, the urinary excretion of NO3 was comparable to the NOR value (CRF, 0. 440 +/- 0.02; NOR, 0.537 +/- 0.08 micromol/min, P = NS). The plasma NO3 levels were higher than in NOR (CRF, 74 +/- 6; NOR, 27 +/- 2 micromol/liter, P < 0.001), and consequently the renal clearance of NO3 resulted as being reduced. During the six months of treatment, although a remarkable steadiness of ARG and NO3 levels was detected in the CRF-C group, the CRF-A group was characterized by a marked and immediate increase of plasma ARG. This was associated, however, with a delayed increment in urinary and plasma NO3 levels and no change in urinary cGMP. In CRF-A, as in CRF-C, blood pressure, proteinuria, glomerular filtration rate, and renal plasma flow did not vary. Likewise, RFR, which was reduced at baseline in CRF, did not improve after ARG. CONCLUSIONS: In moderate CRF, the tonic release of NO is constant and, likely, not impaired, and ARG supplementation does not lead to an enhancement of NO activity, thus resulting in no renal effect.

Adolescent↗
PubMed1999

Bioelectrical impedance measurement: errors and artifacts.

Bioelectrical impedance analysis (BIA) allows simple noninvasive estimation of body water, and it could potentially be a very useful technique for clinical monitoring and study of abnormalities of body water. It has been shown that the total body impedance is dominated by the arm (46%) and leg (44%). The trunk, which represents an average of 46% of the body weight, accounts for only 10% of the total impedance. The objective of the current study was to determine the errors in prediction of body composition from BIA when applied to dialysis patients with measurement on the nondominant arm, postural changes, muscular contractions or cramps, monolateral lymphoedema, arteriovenous fistula, central venous catheter, or vascular graft. We studied 20 healthy subjects, 20 uremics on chronic hemodialysis, 3 uremics with fever (body temperature >38.5 degrees C), 3 uremics with cramps, 3 patients with monolateral lymphoedema of an arm, and 3 patients with a prosthetic fistula on an arm. The results of our study show different values of total body water (TBW) derived by BIA measurements effected on supine or standing position (percentage rate variation = 1.1% to 1.6%), or effected during fever (6%), during cramps (-0.73%), with lymphoedema (25%), or in presence of a native arteriovenous fistula, a catheter in a central vein, or a graft (between -24% and +4%). We concluded that a significant error may occur in the measurement of body composition from whole body BIA when performed in the reported cases.

Adult↗
PubMed1999

Effects of water hardness on urinary risk factors for kidney stones in patients with idiopathic nephrolithiasis.

Both amount and timing of dietary calcium intake influence the recurrence of renal calcium stones. We have evaluated whether the hardness of extra meal drinking water modifies the risk for calcium stones. The urinary levels of calcium, oxalate and citrate, i.e., the main urinary risk factors for calcium stones, were measured in 18 patients with idiopathic nephrolithiasis, maintained at fixed dietary intake of calcium (800 mg/day), after drinking for 1 week 2 liters per day, between meals, of tap water and at the end of 1 week of the same amount of bottled hard (Ca2+ 255 mg/l) or soft (Ca2+ 22 mg/l, Fiuggi water) water, in a double-blind randomized, crossover fashion. As compared with both tap and soft water, hard water was associated with a significant 50% increase of the urinary calcium concentration in the absence of changes of oxalate excretion; the calcium-citrate index revealed a significant threefold increase during ingestion of hard water as compared with respect to soft water (Fiuggi water), making the latter preferable even when compared with tap water. This study suggests that, in the preventive approach to calcium nephrolithiasis, the extra meal intake of soft water is preferable to hard water, since it is associated with a lower risk for recurrence of calcium stones.

Biomarkers↗
PubMed1998

The impact of early normalization of haematocrit by erythropoietin on renal damage in the remnant kidney model.

BACKGROUND: Correction of anaemia in moderate to advanced renal failure is still a matter of debate because of postulated detrimental effects of erythropoietin on the progression of renal damage. METHODS: The renal effects of early normalization of haematocrit (Htc) by erythropoietin (rHuEpo) were investigated from the time of 5/6 nephrectomy up to 8 weeks post-intervention in three groups of remnant kidney model rats: untreated controls (CON), rats receiving 100 UI/kg body-wt of rHuEpo i.p. twice a week (EPO), and rats receiving rHuEpo in which periodic phlebotomies maintained Htc similar to the value of the control group (PHL). The latter group was included to evaluate the direct effects of rHuEpo on renal damage, i.e. independent from Htc correction. RESULTS: Two weeks after renal ablation (basal), Htc decreased in CON and PHL rats (from 49.3+/-1.4% to 43.2+/- 1.1, P < 0.05 and from 49.6+/-1.1 to 43.3+/-1.5%, P<0.05 respectively), while it remained consistently normal in EPO rats (48.9+/-1.2% to 48.9+/-1.50/%, P<0.05 vs other groups). Thereafter Htc did not change throughout the remaining period in all groups. At the end of the study, with respect to basal, resting blood pressure increased significantly by the same extent in CON (+ 13+/-2%) and EPO rats (+ 15+/-5%), while it remained constant in PHL rats. Notably, creatinine clearance significantly decreased in CON (-53+/-8% 8 vs basal) and EPO (-38+/-8% vs basal), while it did not change in PHL rats. Likewise the degree of proteinuria as well as renal morphologic alterations and glomerular hypertrophy/sclerosis was similar in CON and EPO rats, and was significantly more severe than in the phlebotomized group. The only difference detected between CON and EPO group was the greater mesangial hypercellularity in rHuEpo-treated rats. CONCLUSION: In uraemic rats, chronic treatment with rHuEpo aimed at normalization of Htc beginning the early stage of renal failure does not inevitably account for a rise in systemic blood pressure. In addition, neither erythropoietin per se nor the correction of haematocrit accelerates the progression of renal damage when blood pressure remains constant.

Animals↗
PubMed1998

Salt intake and renal outcome in patients with progressive renal disease.

Experimental studies suggest that salt intake plays a critical role in the progressive glomerular filtration rate (GFR) loss of established renal disease; however, this issue has never been addressed in humans. To this aim, we have retrospectively analyzed the clinical data of patients with chronic renal failure (CRF), in whom a low-protein diet was prescribed, over a period of about 3 years. On the basis of the daily urinary sodium output, the patients were divided into two groups: a group of patients constantly ingesting > 200 mEq NaCl/day (high sodium intake, HSD, n = 30) and a group in which salt intake was < 100 mEq/day (low sodium intake, LSD, n = 27). Patients taking diuretics or ACE inhibitors were excluded. At baseline, the LSD group, as compared to the HSD group, was characterized by significantly lower creatinine clearance (24 +/- 2 vs. 28 +/- 2 ml/min) and higher proteinuria (2.9 +/- 0.3 vs. 1.5 +/- 0.2 g/day). Despite the presence of these risk factors for progression, and a similar control of blood pressure (the average of the mean arterial pressure during follow-up was 111 +/- 2 mm Hg in LSD and 107 +/- 2 mm Hg in HSD), the LSD patients showed a better renal outcome: in this group, as compared to HSD, the GFR decline was lower (0.25 +/- 0.07 vs. 0.51 +/- 0.09 ml/min/month, p < 0.05), and proteinuria did not change while it markedly increased in HSD. During follow-up, LSD patients also ingested a significantly lower amount of protein. This study therefore suggests that efficacious salt restriction in CRF patients improves the outcome of renal disease independent from its antihypertensive effects.

Blood Pressure↗
PubMed1997

Fetal proteins and chronic treatment with low-dose erythropoietin.

The potential stimulating effect of erythropoietin on the production of fetal proteins (FPs) has not been explored in human subjects. Therefore, the plasma levels of fetal fibrinogen (FF), carcinoembriogenic antigen (CEA), alpha-fetoprotein (AFP), and fetal hemoglobin (HbF) were measured in 12 uremic hemodialyzed patients before the first administration and after 1, 2, and 3 months of low-dose erythropoietin (r-Hu-EPO; 45 U/kg body wt I.V., thrice weekly). Such a treatment efficaciously increased total hemoglobin (Hb). CEA and AFP increased from 5.8 +/- 1.1 ng/ml and 2.9 +/- 0.9 ng/ml to the final value of 43.2 +/- 3.9 ng/ml and 8.7 +/- 1.1 ng/ml, respectively, in the absence of detectable neoplastic diseases. The levels of FF did not change. HbF levels increased from <3% of Hb to the peak value of 48% at the end of the first month; subsequently, a progressive reduction in HbF was observed. Similar changes were detected in the reticulocyte count (RET). A striking correlation was found between HbF and RET (r = 0.8633, p < 0.0001), indicating that the increment in HbF was dependent on the erythroid activity. In conclusion, this study evidences broader than expected effects of erythropoietin on the synthesis of FP and suggests that (1) r-Hu-EPO markedly increases HbF in a condition of suppressed bone marrow activity, (2) the measurement of the cell proliferation markers CEA and AFP is unreliable during r-Hu-EPO therapy, and (3) the prothrombotic state associated with chronic r-Hu-EPO treatment in patients with uremia cannot be attributed to the presence of FF.

Adult↗
PubMed1997

Pathophysiological role and diuretic efficacy of atrial natriuretic peptide in renal patients.

It has been suggested that renal disease is characterized by the presence of resistance to the natriuretic effects of atrial peptide (ANP). In this study, plasma ANP (pANP) and renal function were evaluated during stepwise infusion of low ANP doses (2, 4, 8, and 16 ng/kg per min) in glomerulonephritic patients with (CRF) or without (GN) moderate renal failure, and in normal subjects (NOR), kept at low-sodium diet (LSD; 35 mEq NaCl/day). To assess the physiological ANP levels, pANP was also measured in the three groups after normal-sodium diet (NSD; 235 mEq NaCl/day). ANP did not affect systemic and renal perfusion at any of the doses tested; a significant increment of GFR was observed only in NOR and GN. The 2-, 4-, and 8-ng/kg doses increased pANP to values overlapping the physiological concentrations measured at NSD; this was associated with a dose-dependent increment of urinary excretion of sodium (UNaV) that reached analogous levels in the three groups. ANP accounted for approximately 40% of the UNaV increment evoked by NSD in patients and in normal subjects. The 16-ng/kg dose led to supraphysiological levels that induced a similar marked enhancement of UNaV (from the basal value of 0.12 +/- 0.02 to 0.42 +/- 0.08 mEq/min in CRF, from 0.13 +/- 0.02 to 0.73 +/- 0.08 in GN, and from 0.09 +/- 0.02 to 0.49 +/- 0.11 in NOR). In CRF, the normal natriuretic response to the highest dose was caused by a larger increase of fractional UNaV that was strictly dependent on the greater pANP increment, as demonstrated by similar changes in the fractional excretion of cGMP, and, in part, on the greater aldosterone decrease. In all groups, ANP also induced a dose-dependent urinary loss of phosphate, potassium, and urea, resulting in a significant 15 to 25% decrease in the plasma levels. Thus, in GN and CRF patients, ANP plays a significant role in the renal handling of sodium; moreover, the achievement of low supraphysiological pANP levels leads to a conspicuous natriuresis associated with unique extranatriuretic effects.

Adult↗
PubMed1997

Physiologic role and diuretic efficacy of atrial natriuretic peptide in health and chronic renal disease.

In recent years, different clinical studies have provided new information on the pathophysiological role and diuretic effectiveness of atrial natriuretic peptide (ANP) in subjects with normal renal function and patients with chronic renal disease. Plasma ANP (pANP) was increased by infusion at the lowest doses ever tested in humans who were on low salt diet to the levels that the same subjects gained when on a normal salt diet; ANP accounted for at least 40% of the increase of natriuresis. Similarly, ANP appeared to be mainly involved in the physiological down-regulation of salt excretion (that is, during the shift from a normal to low-sodium diet). Interestingly, data have been also attained on the efficacy of ANP as diuretic agent when administered at a low nonhypotensive dosage in normals as well as CRF patients. Indeed, low-dose ANP promoted a marked increase of sodium excretion in CRF patients to the same levels observed in normals, likely because the renal patients exhibited a more marked pANP increment secondary to the lower renal catabolism of the infused hormone. Moreover, aldosterone suppression was greater in CRF patients with respect to normals. Furthermore, the fractional urinary excretion of cGMP increased more in CRF patients than in normals. Finally, ANP infusion augmented the urinary losses of the main solutes retained in CRF (urea, potassium, phosphorous) with a significant decrease in the plasma levels. Hence, ANP per se not only plays a significant role in the up- and down-regulation of sodium excretion in healthy state and chronic renal disease, but it may also be considered to be a powerful and unique diuretic agent in CRF at nonhypotensive dosages.

Animals↗
PubMed1997

Enhancement of nitric oxide synthesis by L-arginine supplementation in renal disease: is it good or bad?

L-Arginine is a important component of our diet characterized by multiple physiological and pharmacological actions. In the last decade, this amino acid has attracted major interest since it has been identified as the natural substrate of nitric oxide, and is now recognized to play a major role in the regulation of vascular tone. This review, while summarizing the knowledge of the renal actions of the L-arginine/nitric oxide pathway in health and renal disease, focuses on the potential therapeutic implications of the increase in nitric oxide synthesis attained by L-arginine supplementation.

Animals↗