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Biomedical subjects

S Faenza

Publications and source records attributed to S Faenza.

At least 19 recordsLinked to original sources
PubMed1995

Comparison of hemodialysis versus hemoperfusion in the clearance of high-dose methotrexate in pigs.

To evaluate the different capabilities of hemo-perfusion (HP) and hemodialysis (HD) treatment in resolving the side effects during high-dose methotrexate (MTX) therapy, an experimental comparative study was done. Under general anesthesia, 12 female Large-White pigs, 35 +/- 5 kg body weight, underwent a bilateral renal vessel ligature to create an acute renal failure and avoid the physiologic elimination of MTX. An MTX i.v. infusion was performed using a dose of 12.5 g/m2 and for a specific time according to its pharmacokinetics. The animals were divided into 2 groups of 6 animals each and connected to the extracorporeal circuit; the first group was submitted to a 1-h HP with an anion exchange resin (Dow 1X-2, Dow Chemical) and the second group to 1-h HD with capillary polysulfone fibers (F6, Fresenius). Blood samples were taken at established intervals for hematological and biochemical evaluations. The results demonstrate a higher capability of HP treatment (P < 0.001) related to HD in MTX removal.

Animals↗
PubMed1993

In vitro and ex vivo evaluation of methotrexate removal by different sorbents haemoperfusion.

The administration of high doses of Methotrexate (HDMTX) seems to be very effective in neoplastic treatment. Furthermore high doses of the drug could overcome the Methotrexate (MTX) resistance that it is possible to observe in some kind of cancers. To avoid several serious problems in the therapeutical application of HDMTX such as nephrotoxicity, hepatotoxicity and the difficulty to assess the right therapeutic range of the specific antagonist Leucovorin, a Haemoperfusion (HP) treatment could be very usefulL. In this study 3 anion exchange resins with different active group (trimethylammonium, dimethylethanolammonium and dimethylammina) and a spherical petroleum based charcoal were tested both in vitro and ex vivo to evaluate their capability to remove MTX. These results show a good strength and biocompatibility of the 4 sorbents and demonstrate the active group trimethylammonium resin as the most effective one.

Adsorption↗
PubMed1993

Hemoperfusion--state of art.

The authors make a general review of the state of art in HP with particular reference to the history, the main field of application, and the development of specific and selective sorbents. In this text, attention is paid to the application in the immunological field comparing the therapeutical removal of toxins with different sorbents. Next, the authors describe their experimental study with hemoperfusion using coated anion exchange resins for the treatment of acute respiratory insufficiency, the correction of metabolic alkalosis in pyloric stenosis, the removal of a high dosage of antiblastic agent in conjunction with the study of heparin subtraction by coated resins and finally the development of a particular type of resin for phosphates removal in uremia. These different fields of research recognize the necessity to look for a selective exchange by hemoperfusion because the concept of the "magic filter" that removes everything is not scientifically acceptable. Some explanations are given for the behaviour of the strong anion exchange resins regarding simple or complex ions and the influence of the chemical composition of the matrix. In conclusion, the authors underline that selective removal by HP is actually underutilized considering its potency.

Alkalosis↗
PubMed1993

Monitoring during haemoperfusion (HP).

The relationship between HP and haemodynamic changes is an area which until now has been largely uninvestigated as can be seen from the small amount of material published on this theme. The reasons for this indifference are mainly due to the low extracorporeal flow using during HP. The experiment with a new sorbent on animals must also be analyzed in cardiovascular aspects. This system is the most economical and simple for detecting the elution of vasoactive toxins. In this report the effect on the cardiovascular system of HDMTX and HP with a new trimethylammonium exchange resin versus control groups are evaluated. The results obtained clearly demonstrate the absence of haemodynamic side effects in both groups.

Animals↗
PubMed1993

[Myasthenia and muscle relaxants].

Eighteen myasthenic patients have been operated on under general anaesthesia; 14 subjected to thymectomy and 2 to emergency procedures (caesarean section and laparotomy because of intestinal obstruction). Atracurium (0.3 mg/kg) and vecuronium (0.06 mg/kg) exhibited a long duration of action only in the two cases affected by the more severe signs and symptoms of the disease.

Adolescent↗
PubMed1993

In vivo experimental models on the evaluation of haemoperfusion.

We described some experimental models that were performed in rabbits and in swine in order to evaluate the efficacy of haemoperfusion treatment in hypochloremic alkalosis, uraemia and cytotoxic drug poisoning. In all the models, an extracorporeal circuit was used constituted mainly by a hematic sampling line and a cartridge, containing an anion exchange resin. Access to the blood stream was achieved by isolation and catheterization of the vessels either of the neck or of the leg, or both. The experimental model for the evaluation of haemoperfusion in hypochloremic alkalosis was carried out in rabbits by a pyloric stenosis because its size and weight are similar to new-born humans and its stomach is a simple monogastric one. The hypochloremia and alkalosis were achieved in only 4 hours. The other two experimental models were carried out in pigs because, in these cases, it was better to choose a large size animal with a nutritional similarity to humans, and with the capability to produce a stable chronic renal failure. The pigs were submitted to a bilateral ureter ligature to create a chronic renal failure or to a bilateral renal vessel ligature to avoid the physiologic precipitation of some drugs in renal tubules.

Alkalosis↗
PubMed1992

Phosphate removal by resin hemoperfusion efficacy and biocompatibility of a new exchange resin.

A new coated anionic exchange resin for blood purification specifically designed to remove phosphates was experimentally employed in animals. 3 pigs, in which uremia had been surgically induced, underwent 6 extracorporeal hemoperfusion sessions (2 per pig) with a cartridge containing 100 gr of resin. The phosphate clearance proved satisfactory, values being 120 ml/min after 10' and around 80 ml/min after 2 hours. The biocompatibility of the resin and of the coating membrane was satisfactory. The negligible variation in pH and plasma bicarbonate during all sessions confirmed the low absorption by the tested resin of other blood anions competing with phosphate.

Animals↗
PubMed1992

Hemoperfusion with a new anion exchange resin corrects the metabolic alkalosis in pyloric stenosis: an experimental demonstration.

An experimental model of hypertrophic pyloric stenosis was made by suture of the pyloric wall and gastrostomy in 10 rabbits under general anesthesia. Blood sampling indicated severe alkalosis and hypochloremia 3h 30 min after surgery. To correct the derangement, we tested an ion exchange resin (Dowex SAR), coated with a methacrylic hydrogel. A cartridge containing 18 g of this resin was inserted in an extracorporeal circuit. This chloride charged resin achieved uptake of HCO3- ions, and elution of Cl- ions. The electrolytic balance was fully restored after 10 min of treatment.

Alkalosis↗
PubMed1985

Demonstration of surfactant phospholipids in frozen sections of the lung.

Saturated phospholipids are known to be the only surface active compounds present in the surfactant system of the lung. Using light microscopy, the identification in situ of pulmonary surfactant has always been hampered by the lack of satisfactory fixatives and dyes which act on saturated phospholipids fast enough to prevent the complete loss of surfactant in the solutions. In this study we adopted the tricomplex flocculation proposed by Elbers et al. (1965) to fix surfactant phospholipids on frozen sections obtained from human, pig and rat lungs. Small pieces of lung tissue were quickly frozen in freon 22 kept at -75 C.; eight micron sections were cut in a cryostat, air dried and immersed for 30s-5m in a 0.05 N Pb(NO3)2 + K3Fe (CN)6 solution in 10% formalin. Lead ions bound to the choline portion of phospholipid molecules were subsequently revealed in a 30 mM ammonium sulfide solution. This procedure delineates a dark brown filmy structure in the respiratory parenchyma, which is very loosely attached to the alveoli and appears to be related to lung surfactant. Preliminary lung lavage or pretreatment of sections with saline, aldehyde fixatives and several organic solvents, fully or partially abolish the stain.

Animals↗