G A Nicolai

Azienda Ospedaliera Universitaria Senese, Siena, Tuscany, Italy

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Publications (11)14.38 Total impact

  • Luigi Capotondo, Giulia Adriana Nicolai, Guido Garosi
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    ABSTRACT: In recent years, echographic studies of the kidney have improved radically due to new technologies which have recently become available. Among these, perhaps the most useful one is the ultrasonographic (US) procedure for the simultaneous laboratory and clinical workup of patients affected with acute nephropathic syndromes. However, traditional B-mode ultrasonography lack of sensibility and specificity in identifying and evaluating Acute Kidney Injury (AKI) is well known. Although the most objective measure in the study of different nephropathies remains by far the biopsy, several studies have indicated the usefulness of combining the B-mode ultrasound (US) with echo-color Doppler as a tool in determining intrarenal parenchymal arteries in the for differential diagnosis and predicion of clinical outcomes. In fact, the resistivity index (RI), determined by the formula: IR = (peak systolic velocity)--(end-diastolic or telediastolic velocity)/(peak systolic velocity) can be, after proper technical correction, easily measured at the level of the arcuate arteries or at the interlobar arteries. The final value is the average of 3-5 peaks, consecutively determined for each kidney at the upper pole, in the mesorenal area and also at the lower pole. The variation in normal IR values is < or = 0.70 with the difference diminishing progressively from segmental to interlobar vessels. Acute Kidney Injury (AKI) is perhaps one of the most important areas for the application of the Resistivity Index (RI). The differential diagnosis between prerenal AKI (which is functional and reversible if the cause of hypoperfusion is corrected) and renal AKI (which is organic and mainly caused by tubular necrosis (ATN) or acute interstitial nephritis) is facilitated by measurements of the RI, in addition to the normal clinical laboratory and clinical data. In fact, most pre-renal AKI patients show normal parenchymal vascular flow, with RI < 0.70, whereas those with AKI due to NTA have a reduced parenchymal perfusion, accompanied by elevated RI values, prior to any evidence of abnormal values of creatinine or of oligoanuria. Follow-up of patients with both renal and prerenal AKI by serial monitoring of RI during medical treatment of AKI shows a progressive reduction and ultimately the normalization of RI values of renal parenchymal vessels and often precedes the return to normal kidney function. In post-renal obstructive AKI patients, absolute values of RI > 0.70 on the obstructed kidney and a RI difference (deltaRI) between the two kidneys of > 0.06-0.08 are considered diagnostic of an obstruction. Elevated values of RI are also considered useful in the diagnosis of hemolytic-uremic syndrome (HUS) and are a significant predictor of prognosis: the normalization of IR precedes the return of normal renal functionality. Similarly, measurement of RI in patients with liver disease and normal renal function may help in early detection of latent hepato-renal syndrome. Although the IR is not, strictly speaking, a measure of renal function it may nevertheless be correlated with it especially if elevated arterial resistivity is accompanied by a reduction in renal function itself. Thus, IR may be considered a useful predictive index in specific clinical settings.
    Archivio italiano di urologia, andrologia: organo ufficiale [di] Società italiana di ecografia urologica e nefrologica / Associazione ricerche in urologia 12/2010; 82(4):275-9.
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    ABSTRACT: In a previous experimental study we showed that the administration of a large water load in a short time increases the urinary flow and the transport capacity in the excretory tract of the rabbit ureter. In human subjects drinking a water load of 25 ml/kg(BW) in 30 minutes, diuresis, creatinine and urea clearance increase more than in those drinking the same load in 24 hours. The aim of the present study was to investigate possible correlations between percent reduction and baseline values of serum urea, creatinine, folic acid, and magnesium in humans. 20 volunteers were divided in two groups. Subjects in group 1 received a water load of 25 ml/kg(BW) in 24 hours followed by the same load in 30 minutes. Subjects in group 2 received the same water load but in inverse order. Before and after each water administration, the following variables were measured and compared: diuresis, serum urea, creatinine, folic acid and magnesium concentration, and urea and creatinine clearance. Serum urea and folic acid concentration decreased up to 40% after administration of the water load in 24 hours. Serum creatinine concentration decreased up to 20% after administration of the water load in 30 minutes. The concentration drop of these metabolites increased with increasing baseline metabolite concentrations.
    The International journal of artificial organs 05/2010; 33(5):317-20. · 1.76 Impact Factor
  • Nicola Di Paolo, Giulia Nicolai
    International Urology and Nephrology 03/2010; 42(1):243-4. · 1.33 Impact Factor
  • Peritoneal dialysis international : journal of the International Society for Peritoneal Dialysis. 01/2010; 30(5):504-5.
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    Nicola Di Paolo, Giulia A Nicolai, Guido Garosi
    Peritoneal dialysis international: journal of the International Society for Peritoneal Dialysis 11/2008; 28 Suppl 5:S5-9. · 2.21 Impact Factor
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    ABSTRACT: In previous studies we were successful in demonstrating that the administration of water over a short period of time increases the transport capacity in the excretory tract of rabbit ureters by increasing urinary volume in the ureter from 0.3 ml/min to 10 ml/min. This phenomenon may explain the effect of water therapy performed in thermal spas, where the administration of 1-2 liters of mineral water is performed in 30-60 minutes. The aim of the present study is to investigate if this increased transport capacity can act also in the renal tubular apparatus to modify the excretion of some endogenous substances. We evaluated daily renal clearances in ten subjects under basal conditions during supplemental administration of 25 ml/kg of mineral water over a 24-hour period and during the administration of the same amount of water over a 30-minute period. Subjects who drank a water load of 25 ml/Kg over 30 minutes showed a higher diuresis than that observed in those who drank the same amount over a 24-hour period. Creatinine and urea clearance at 24 hours were significantly higher in subjects who drank the water load over 30 minutes. Serum magnesium levels and folic acid levels were also significantly higher in subjects who drank the water load over 30 minutes. Water administration over a short period of time seems to modify the daily excretion of some endogenous metabolites.
    The International journal of artificial organs 01/2008; 30(12):1109-15. · 1.76 Impact Factor
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    ABSTRACT: Sixteen years ago rabbit and human mesothelial cells were successfully cultured and autoimplanted. The aim of the study was merely to demonstrate that mesothelial implant was possible and interesting not only in peritoneal dialysis, but also in the vaster field of medicine and surgery concerning all the mesothelial districts of the body. The aim of this paper is to recollect the steps which have led to autologous mesothelial transplantation and verify if the technique has been validated and adopted by others. Review of the literature published in the last 15 years shows that intraperitoneal transplantation of mesothelial cells has been effective in reducing the formation of peritoneal adhesions, and in remodeling the area of mesothelial denudation. New studies on the mesothelial cell opened the way to construction of transplantable tissue-engineered artificial peritoneum, to the utilization of mesothelial progenitor cells and to find simple methods to collect autologous mesothelial cells. Finally mesothelial transplantation may represent a new neovascular therapy in the prevention and treatment of ischemic coronary heart disease.
    The International journal of artificial organs 07/2007; 30(6):456-76. · 1.76 Impact Factor
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    ABSTRACT: Milky spots are very small omental organs, in contact with peritoneal membrane, devoid of capsule and consisting of macrophages, lymphocytes and a few plasma cells supported by blood and lymphatic vessels. The exact role of these particular organs is still not clear, but they are similar to lymphatic structures and it is clear that they play a role in peritoneal infection and abdominal tumors. Peritoneal dialysis seems to activate the milky spots changing their morphology. The authors try to formulate some hypotheses on the role played by these little omental organs during autologous mesothelial transplant.
    The International journal of artificial organs 07/2007; 30(6):520-6. · 1.76 Impact Factor
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    ABSTRACT: A frequent problem that family doctors face is the meaning of small quantities of blood or protein in urine samples. Patients with this problem are often either neglected or referred to specialists for complex, expensive, and often invasive diagnostic procedures. Exercise testing has never been considered in nephrology, except for some attempts in diabetic patients. We report on a study conducted over 12 years with patients referred for slight hematuria and/or proteinuria to determine whether exercise testing could be a diagnostic aid in some or all of them. We performed exercise testing using a treadmill preceded and followed by urine analysis, with a kidney biopsy within 10 days. Of the 94 patients enrolled in the study, only those with a positive exercise test turned out to have parenchymal nephropathy. At the end of the study, we simplified the quantification of exertion, dispensing with the treadmill and drastically reducing the number of urinary parameters considered. In patients with histological evidence of kidney damage, most of the variables increased significantly after the test. Statistical analysis also showed that determination of proteinuria and hematuria alone guaranteed maximum predictability. We found that it is also possible to simplify the quantification of effort/exertion and to drastically reduce the number of urinary parameters and still obtain significant results. Exercise testing provides useful information about the significance of microhematuria and proteinuria, reducing the number of cases that need to be referred to specialists. The method needs to be validated in other studies, but our results suggest that family doctors could use simple dipsticks to screen the many cases of microhematuria or proteinuria observed in daily practice. The method seems useful in eliminating doubts and unnecessary diagnostic costs.
    European Journal of Internal Medicine 04/2007; 18(2):135-40. · 2.05 Impact Factor
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    ABSTRACT: The self-locating catheter invented by Nicola Di Paolo has been increasingly used in Italy and elsewhere since 1994, with about a thousand patients currently implanted every year. Twelve grams of tungsten inserted in the tip of the conventional Tenckhoff catheter during extrusion do not significantly change its form, but suffice to keep the tip firmly in the Douglas cavity. The validity of the new catheter is confirmed by a multicentric controlled study in a large population of peritoneal dialysis patients. This trial showed that patients with the new catheter have fewer episodes of peritonitis, tunnel infection, cuff extrusion, catheter malfunction, obstruction and leakage. This paper outlines the present situation and reports a comparative analysis of the costs of Tenckhoff and self-locating catheters.
    The International journal of artificial organs 02/2006; 29(1):113-22. · 1.76 Impact Factor
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