N. Di Paolo

Morphology of the Peritoneal Membrane during Continuous Ambulatory Peritoneal Dialysis

In the last 3 years we performed 52 peritoneal biopsies (PB) in 31 patients on continuous ambulatory peritoneal dialysis (CAPD). Samples of the parietal peritoneum were obtained either during insertion of the catheter or while it was being repositioned or removed. PB was performed in 13 patients before initiating CAPD and in 27 after 7-49 months of CAPD while 7 had PB during peritonitis, and, again, in 5 of these cases, PB was repeated after 1-4 months for light, electron transmission, and scanning electron microscopy. BP after CAPD showed that mesothelial cells were irregularly spaced, and at times we observed alterations in the cellular structure. Rarely were these cells degenerating, while rarefaction and in many cases complete absence of microvilli were observed. In some cases the submesothelial layers showed rarefaction of the connective tissue and sclerosis. During peritonitis, PB showed more alterations with marked degeneration and in some cases necrosis of the mesothelium and alterations of connective tissue. PB performed some months after peritonitis showed only a partial regression of these alterations and sclerotic patches, and no microvilli were noted in the mesothelium.

Acute Renal Failure from Inhalation of Mycotoxins

Mysterious deaths of archeologists after opening Egyptian tombs have been suspected to be secondary to inhalation of mycotoxin, however, the hypothesis has never been verified. Recently, we observed a case of acute renal failure (ARF) undeniably due to inhalation of ochratoxin of Aspergillus ochraceus. After spending 8 h in a granary which had been closed for several months, a farmer and his wife suffered temporary respiratory distress; 24 h later, the woman developed nonoliguric ARF and biopsy revealed tubulonecrosis which healed in 24 days. Toxic substances were not found, but a strain of A. ochraceus producing ochratoxin was isolated from the wheat.

Prevention of peritoneal sclerosis: a new proposal to substitute glucose with carnitine dialysis solution (biocompatibility testing in vitro and in rabbits).

Aim Commercial glucose peritoneal dialysis solutions expose the peritoneum to hyperosmolar glucose containing variable amounts of non-enzymic breakdown products of glucose. These solutions are toxic for the peritoneum. The aim of the present study is to compare in vitro and in vivo characteristics of a new dialysis solution containing carnitine, a naturally occurring compound, as substitute of glucose. Material and Methods We compared in vitro and in the rabbit a new peritoneal dialysis solution containing carnitine, with two standard bicarbonate glucose peritoneal dialysis solutions and a solution containing icodextrin. Results In vitro and in vivo the solution containing carnitine seems to be more biocompatible than standard glucose solutions and those containing icodextrin. Conclusions In our study the peritoneal dialysis solution containing carnitine seems to prevent the mesothelial changes observed with solutions containing glucose. Since carnitine has been extensively studied and seems to be well tolerated by hemodialysis patients, even at high doses for long periods, clinical trials in humans may be planned in the near future.

Simple peritoneal sclerosis and sclerosing peritonitis: related or distinct entities?

Aim The etiopathogenesis of sclerosing peritonitis is still debated, with some sustaining that it is a rare form of progression of simple peritoneal sclerosis and others that it is a primitive form. The aim of the present research was to clarify this question. Material and Methods 438 peritoneal biopsies from 253 patients were re-examined. 174 were obtained prior to peritoneal dialysis and 224 after various periods of dialysis. Forty biopsies were from peritoneal dialysis patients who developed sclerosing peritonitis. Peritoneal morphology was studied for signs of transition from simple sclerosis to sclerosing peritonitis. Results Evidence was found sustaining the hypothesis that simple sclerosis to sclerosing peritonitis patients have distinct pathologies. Conclusions The results confirm previous observations, excluding the existence of any type of relation between simple peritoneal sclerosis to sclerosing peritonitis.

State of the art on autologous mesothelial transplant in animals and humans.

Sixteen years ago rabbit and human mesothelial cells were successsfully cultured and autoimplanted. The aim of the study was merely to demostrate 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 autolougous mesothelial transplantation and verify if the tecnique 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 costruction of transplantable tissue-engineered artificial peritoneum, to the utilization of mesothelial progenitor cells and to find simple metods to collect autologous mesothelial cells. Finally mesothelial trasnsplantation may represent a new neovascular therapy in the prevention and treatment of ischemic coronaric heart disease.

Bleeding Tendency of Chronic Uremia Improved by Vascular Factor

Complex hemostatic changes in uremic patients are characterized by platelet distress and prolonged bleeding time. Dialysis corrects platelet function and improves the bleeding time but introduces a tendency to thrombophilia. The uremic patient is thus an excellent model for the evaluation of hemostatic drugs. VUEFFE (VF) is a new hemostatic agent which reduces bleeding time without modifying clotting parameters. Changes in hemostasis and coagulation were studied in 42 hemorrhagic uremic subjects in dialysis or on conservative management. The patients were divided into two groups, one of which was given oral VF and the other oral placebo. 84% of those receiving VF ceased bleeding within 15 days (compared to 25% for placebo) and there was a significant reduction in bleeding time. The drug can be given orally or parenterally, is well tolerated and without side effects, making it suitable for administration to hemorrhagic uremic patients.

Experimental evaluation of transport force in the rabbit ureter

Background Cleaning the urinary tract by so-called “wash-out effect” and promoting high diuresis has long been advocated but has had very little scientific backing and few prospective studies in international journals. Aim To verify whether the physical laws describing the transport force of water in rivers and pipes are also valid for urinary outflow. Methods A laboratory model for measuring transport force, given liquid and solid capacity, was adapted to create an in vivo model based on the rabbit urinary tract. Results Fluid flow in the rabbit renal pelvis and ureters was found similar to flow in pipes, obeying the physical laws of water transport to some extent. When the quantity of liquid flowing in the urinary tract in unit time was doubled, the transport force increased by various orders of magnitude. When the liquid increased by a larger factor, the transport force became enormous. Conclusions The results confirm the utility of maintaining high diuresis in patients with renal calculus, but stress the utility of drinking 1–2 liters of hypotonic water in a short time to obtain an enormous increase in transport force which increases the probability of a cleansing effect.

Vantaggi, Svantaggi, Esecuzione e Indicazioni Della Dialisi ad Ago Singolo

nefrologi spesso non vedono di buon occhio la dialisi con ago singolo perche la considerano inadeguata, tuttavia sono costretti ad impiegarla ampiamente in molte situazioni in cui edifficile ottenere il doppio accesso vascolare. Questo atteggiamento di sfiducia e largamente diffuso in Italia, mentre in molti Paesi esteri la dialisi ad ago singolo eimpiegata molto piu spesso che da noi (1). I vari sistemi monoago si suddividono in sistemi a una pompa e sistemi a pompa doppia. Nei sistemi a pompa singola (Figg. 1-3) Iinversione di flusso attraverso Iago richiede Iazione di una 0 due clamps poste lungo ilcircuito , ilcui azionamento puo essere regolato da variazioni di pressione ematica a livello del circuito stesso 0 da sistemi a tempo. I sistemi a pompa singola non sono oggi considerati adegu ati al raggiungimento di una corretta efficacia dialitica , perche non garantiscono un flusso ematico soddisfacente (Fig. 4): durante la fase di mandata il flusso edecrescente nel tempo, in quanta la reinfusione avviene solo in base aile caratteristiche di compliance del circuito . I sistemi piu recenti prevedono Iuso di 2 pompe che operano sequenzialmente, una situata prima del filtro e Ialtra dopo: in questa modo non ce bisogno di nessuna clamp perche le pompe stesse fermandosi occludono il circuito . Le versioni commerciali piu recenti (Fig . 5) comprendono un secondo circuito di monitoraggio della pressione per prevenire 10 sviluppo di una alta pressione non monitorizzata tra la pompa a valle del filtro e Iaccesso vascolare del paziente, con rischio di formazione di ematomi 0 di danni alia fistola. II vantaggio principale dei sistemi a doppia pompa e dunque Iottenimento di flussi ematici adeguati (Fig. 6)e uniformi sia in aspirazione che in mandata. Un altro vantaggio e la possibilita di far girare Ie due pompe a velocita diverse: cio risulta molto utile per ottimizzare il rendimento della pompa arteriosa e quindi della fase di aspirazione. In definitiva, i sistemia doppia pompa sono oggi considerati gli unici adeguati per la dialisi ad ago singolo .