[Bilirubin removal with Coupled Plasma Filtration and Adsorption in patients affected by hilar cholangiocarcinoma]. / Rimozione della bilirubina con Coupled Plasma Filtration and Adsorption in pazienti con colangiocarcinoma ilare.

BACKGROUND: Patients affected by hilar cholangiocarcinoma are eligible for surgery only in the 20-30% of the cases and postoperative mortality is 40-50%. Many specialists are involved in the treatment of this disease, like surgeons, gastroenterologists, oncologists and radiotherapists. Recent studies have shown that preoperative bilirubinaemia is a predictor of morbidity and mortality after surgery. Coupled Plasma Filtration and Adsorption (CPFA) is a blood purification extracorporeal therapy recommended for sepsis and able to reduce bilirubinaemia. METHODS: We treated 10 patients referred to our centre affected by hilar cholangiocarcinoma complicated by obstructive jaundice with 34 CPFA sessions to test its ability to reduce preoperative bilirubin levels and we checked for mortality at 90 days. RESULTS: CPFA reduced preoperative bilirubin of 30% for session; it also improved others inflammation and coagulation tests. Mortality at 90 days was 40%. CONCLUSIONS: CPFA is an effective therapy for hyperbilirubinaemia. Lowering preoperative bilirubinaemia and improvement of coagulation tests subsidized the management of the patients but in our study did not affect postoperative mortality. Further studies to evaluate the indications for treatments that remove bilirubin in this setting are needed.

Heparin induces harmless fibril formation in amyloidogenic W7FW14F apomyoglobin and amyloid aggregation in wild-type protein in vitro.

Glycosaminoglycans (GAGs) are frequently associated with amyloid deposits in most amyloid diseases, and there is evidence to support their active role in amyloid fibril formation. The purpose of this study was to obtain structural insight into GAG-protein interactions and to better elucidate the molecular mechanism underlying the effect of GAGs on the amyloid aggregation process and on the related cytotoxicity. To this aim, using Fourier transform infrared and circular diochroism spectroscopy, electron microscopy and thioflavin fluorescence dye we examined the effect of heparin and other GAGs on the fibrillogenesis and cytotoxicity of aggregates formed by the amyloidogenic W7FW14 apomyoglobin mutant. Although this protein is unrelated to human disease, it is a suitable model for in vitro studies because it forms amyloid-like fibrils under physiological conditions of pH and temperature. Heparin strongly stimulated aggregation into amyloid fibrils, thereby abolishing the lag-phase normally detected following the kinetics of the process, and increasing the yield of fibrils. Moreover, the protein aggregates were harmless when assayed for cytotoxicity in vitro. Neutral or positive compounds did not affect the aggregation rate, and the early aggregates were highly cytotoxic. The surprising result that heparin induced amyloid fibril formation in wild-type apomyoglobin and in the partially folded intermediate state of the mutant, i.e., proteins that normally do not show any tendency to aggregate, suggested that the interaction of heparin with apomyoglobin is highly specific because of the presence, in protein turn regions, of consensus sequences consisting of alternating basic and non-basic residues that are capable of binding heparin molecules. Our data suggest that GAGs play a dual role in amyloidosis, namely, they promote beneficial fibril formation, but they also function as pathological chaperones by inducing amyloid aggregation.

A specific enzymatic high-performance liquid chromatography method to determine N-methyl-D-aspartic acid in biological tissues.

Recently we demonstrated that N-methyl-D-aspartic acid (NMDA) is present as an endogenous compound in the nervous tissues and endocrine glands of the rat where it plays a role in the regulation of the luteinizing hormone, growth hormone, and prolactin (FASEB J. 14 (2000) 699; Endocrinology 141 (2000) 3861). Based on the prediction that NMDA could have future importance in neuroendocrinology, we have devised an improved method for the specific and routine determination of NMDA in biological tissue. This method is based on the detection by HPLC of methylamine (CH(3)NH(2)) which comes from the oxidation of NMDA by D-aspartate oxidase, an enzyme which specifically oxidizes NMDA, yielding CH(3)NH(2) as one of the oxidative products of the reaction. The sensitivity of the method permits the accurate determination of NMDA in the supernatant of a tissue homogenate at levels of about 5-10 picomol/assay. However, for those tissues in which the concentration of NMDA is less than 1nmol/g, the sample must be further purified by treatment with o-phthaldialdehyde in order to separate the NMDA from the other amino acids and amino compounds and then concentrated and analyzed by HPLC. Using this method we have conducted a comparative study in order to measure the amount of NMDA in neuroendocrine and other tissues of various animal phyla from mollusks to mammals.