Papers by Stefano Saffioti
Urologic Radiology, 1986
Urinary water and solute excretion before and for 40 minutes after intravenous bolus injection of... more Urinary water and solute excretion before and for 40 minutes after intravenous bolus injection of a nonionic (iopamidol) or an ionic medium (sodium meglumine diatrizoate) have been studied in subjects with normal renal function. Iopamidol produced less urinary losses of water, potassium, sodium, and chloride than did diatrizoate; uric acid excretion was also less enhanced. Surprisingly, both contrast agents produced a comparable increase in urinary pH and bicarbonate excretion. These data show that nonionic agents produce fewer changes in urinary excretion of water and solutes; the less enhanced excretion of uric acid after a nonionic medium may be an important reason to choose the latter agents for urography in patients at risk for urate neophropathy.
The International Journal of Artificial Organs, 2012
Mixed diffusive-convective dialysis therapies offer greater removal capabilities than conventiona... more Mixed diffusive-convective dialysis therapies offer greater removal capabilities than conventional dialysis. The aim of this study was to compare two different on-line, post-dilution hemodiafiltration (HDF) treatments with regard to achieved convective volume and middle-molecule dialysis efficiency: standard volume control (sOL-HDF) and automated control of the transmembrane pressure (TMP) (UC-HDF). We enrolled 30 ESRD patients (55.9 ± 14.0 years, 20/10 M/F) in a randomized, prospective, cross-over study. The patients received a 3-month period of sOL-HDF followed by UC-HDF for a further 3 months, or vice versa, using the same dialysis machine. In sOL-HDF, fixed exchange volumes were set according to a filtration fraction greater than or equal to 25%. In UC-HDF therapy, the exchanged volume was driven by a biofeedback system controlling the TMP and its set point in a double loop. Patients maintained their treatment time, dialyzer, blood flow rate, and anticoagulant regimen unchanged throughout the study. Greater convective volumes were achieved in UC-HDF than in sOL-HDF (23.8 ± 3.9 vs.19.8 ± 4.8 L; p<0.001) with high pre-dialysis Ht value (sOL-HDF 34.0 ± 4.5% and UC-HDF 34.0 ± 4.4%; p = 0.91). The average clearance values of ß2m and P were higher in UC-HDF than in sOL-HDF (respectively 123 ± 24 vs. 111 ± 22 ml/min, p<0.002 and 158 ± 26 vs. 152 ± 25 ml/min, p<0.05). Moreover, the UC-HDF mode led to a significantly increased rate of call-free sessions from 88% to 97% (p<0.0001). This study showed that the biofeedback module, applied to the automatic control of TMP in on-line HDF, results in higher convective volumes and correspondingly higher ß2m and P clearances. By making the HDF treatment more automated and less complex to perform, it significantly reduced the staff workload.
Urologic Radiology, 1991
Pseudoxanthoma elasticum (PXE) is a rare hereditary disease whose basic abnormality is degenerati... more Pseudoxanthoma elasticum (PXE) is a rare hereditary disease whose basic abnormality is degeneration of elastic tissue, with calcification of the tonaca media of the arteries, and typical yellowish papules of the skin. We report the sonographic findings observed in a young patient with PXE at the level of the kidneys: fine hyperechogenic spots suggesting small calcifications were diffuse at the corticomedullary junction; however, normal waveforms were obtained at the level of intraparenchymal renal vessels. The presence of this structural pattern in a young patient with dermatologic abnormalities should lead to the consideration of PXE in the differential diagnosis list.
Mineral and electrolyte metabolism, 1997
Metabolic acidosis causes a cooperative participation of different organs such as the liver, kidn... more Metabolic acidosis causes a cooperative participation of different organs such as the liver, kidney, and muscle in restoring acid-base balance. In splanchnic organs, metabolic acidosis has repercussions on several nitrogen metabolism pathways. The decrease in urea synthesis due to reduced activity of urea cycle enzymes, ammonia uptake and amino acid transport, and changes in glutamine metabolism support renal ammoniagenesis thus offering a response to rid the body of excess protons. While some of the mechanisms are adaptive others may be harmful for the body. Metabolic acidosis may have effects on splanchnic protein turnover. In severe acidosis, synthesis of secreted liver proteins may be reduced. Acidosis may also modulate the response of the liver to growth hormone (GH) for insulin-like growth factor-I synthesis, thus inducing a state of GH resistance. Splanchnic abnormalities in acidosis might contribute to the malnutrition observed in uremia.
Contributions to nephrology, 1994
The American journal of clinical nutrition, 1995
Muscle exchange of amino acids (AAs) was evaluated by using the arteriovenous-difference techniqu... more Muscle exchange of amino acids (AAs) was evaluated by using the arteriovenous-difference technique across the leg in seven patients with chronic renal failure (CRF) and eight control subjects before and for 75 min after the ingestion of an AA mixture simulating an animal-protein meal. Total AAs increased in arterial blood much more in patients with CRF after AA ingestion than in control subjects, as a consequence of an exaggerated increase in nonessential AAs (NEAAs) (+127%). Moreover, total AAs were taken up by the leg in larger amounts than in control subjects (+71%, P < 0.0025) because of increased uptake of NEAAs (+156%, P < 0.005). Branched-chain AA uptake by the leg was, in absolute values, similar to that of control subjects; however, because of the increased uptake of total AAs, branched-chain AA uptake was only 30% of total AA extraction, compared with 46% in control subjects. Abnormalities in AA uptake by muscle paralleled those in arterial AAs. In fact the same AAs ...
Contributions to nephrology, 1985
The American journal of clinical nutrition, 1987
Arterial whole blood levels of amino acids (AA) were determined in patients with chronic renal fa... more Arterial whole blood levels of amino acids (AA) were determined in patients with chronic renal failure (CRF) and in healthy volunteers before and for 75 min after the ingestion of an AA mixture simulating the AA content of an animal-protein meal. In CRF patients, total AA increased more than in control subjects as a consequence of an exaggerated rise in nonessential AA (+86%), mainly glutamine, proline, glutamate, serine, glycine, and alanine. Total essential AA in patients increased as much as in control subjects; however, threonine and phenylalanine showed greater increases while leucine had a smaller increase. As a consequence of the observed alterations, a striking unbalance in the postprandial pattern of arterial AA ensued in CRF patients. The flow of AA to all the organs is altered during the absorptive phase, which is crucial for body nitrogen-pool replenishment.
Contributions to nephrology, 1987
Kidney international. Supplement, 1987
Contributions to nephrology, 1988
Contributions to nephrology, 1989
Kidney international. Supplement, 1989
Contributions to nephrology, 1990
Contributions to nephrology, 1991
Contributions to nephrology, 1991
... The authors wish to thank Mr. M. Marchelli and Mr. M. Bruzzone for their excellent technical ... more ... The authors wish to thank Mr. M. Marchelli and Mr. M. Bruzzone for their excellent technical assistance and Mrs. F. Tincani and Mrs. G. Bonifazio for preparation of the manuscript and figures. Page 123. ... Raven Press, New York, 1985, pp 1471-1490. ...
Contributions to nephrology, 1992
Journal of Diabetic Complications, 1991
Renal metabolism of amino acids (AAs) was evaluated in 5 patients with early IDDM, and in 7 contr... more Renal metabolism of amino acids (AAs) was evaluated in 5 patients with early IDDM, and in 7 controls (C) in the basal state for 80 minutes after the ingestion of an AA mixture simulating an animal protein meal. Insulin was withdrawn 20 hours before the study. Renal metabolism of AAs was evaluated by the arterial-venous difference technique. In the basal state in IDDM, as in C, the kidney takes up large amounts of a few nonessential AAs (NEAAs): it releases many NEAAs and a few essential AAs (EAAs). After AA ingestion in C, renal extraction of most EAAs, mainly BCAAs, Lys, and Thr, occurs; Pro extraction also increases and a significant uptake of Gly, Glu, Asp, Orn, and Tyr takes place. EAA extraction accounts for 30-40% of total AA uptake. In IDDM, after AA ingestion, a) renal uptake of total AAs is significantly lower, owing mainly to a markedly lower uptake of BCAAs, Lys, and also of Pro, Orn, and Ala; b) renal EAA uptake accounts for less than 20% of total AA extraction. These results indicate that in IDDM postprandial renal N repletion is impaired and unbalanced.
Urologic Radiology, 1991
Pseudoxanthoma elasticum (PXE) is a rare hereditary disease whose basic abnormality is degenerati... more Pseudoxanthoma elasticum (PXE) is a rare hereditary disease whose basic abnormality is degeneration of elastic tissue, with calcification of the tonaca media of the arteries, and typical yellowish papules of the skin. We report the sonographic findings observed in a young patient with PXE at the level of the kidneys: fine hyperechogenic spots suggesting small calcifications were diffuse at the corticomedullary junction; however, normal waveforms were obtained at the level of intraparenchymal renal vessels. The presence of this structural pattern in a young patient with dermatologic abnormalities should lead to the consideration of PXE in the differential diagnosis list.
Contributions to Nephrology, 2003
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Papers by Stefano Saffioti