Cardiac Surgery in Patients With Liver Cirrhosis (CASTER) Study: Early and Long-Term Outcomes

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The intriguing role of Rifaximin in gut barrier chronic inflammation and in the treatment of Crohn’s disease

Introduction: The gastrointestinal tract acts as a functional unit organized as a semipermeable multilayer system, in which commensal gut microbiota represents the anatomical barrier. Recently, several studies have highlighted the involvement of gut microbiota in inflammatory bowel diseases (IBD) pathogenesis, in sustaining gut barrier chronic inflammation, and in conditioning disease course and therapeutical response. This evidence provides a rationale for treating patients with gut microbiota modifiers. Among these, Rifaximin represents a non-traditional antibiotic able to act as a ‘eubiotic’ on intestinal barrier.

Area covered: The purpose of this narrative review is to explore the impact of Rifaximin on gut barrier and gut microbiota in IBD, in particular in Crohn’s disease (CD), and to analyze its potential therapeutic applications.

Expert opinion: The possibility of a beneficial activity of Rifaximin in chronic intestinal inflammation and CD has been debated and evaluated with different studies having obtained promising but still preliminary data. Larger trials are therefore needed. This gut-specific antibiotic could represent an alternative to systemic antibiotics thanks to its favorable safety profile and promising efficacy data. Rifaximin could exert, when appropriate, a synergic effect with immunomodulators in IBD, acting on both the microbial and the immunological sides of gut barrier impairment.     

Four-year follow-up of larger-diameter implants placed in fresh extraction sockets using a resorbable membrane or a resorbable alloplastic material

PURPOSE: The aim of this randomized study was to evaluate and compare the long-term success rates of cylindric, screw-type titanium implants with a larger diameter (5.9 mm) that were placed in fresh extraction sockets in association with resorbable bone substitutes or a resorbable membrane. MATERIALS AND METHODS: Eighty-three partially edentulous adult patients, selected from among those treated in 1997 and 1998 at the San Raffaele Institute in whom 1 or more implants had been placed into fresh posterior mandibular or maxillary sockets, were included in the study. A total of 111 implants were placed, 36 in mandibles and 75 in maxillae. Fifty-six implants were placed in combination with resorbable hydroxyapatite (HA group) and 55 with a resorbable membrane (MR group). Intraoral radiographs and follow-up examinations, including verification of implant stability via the Periotest, were carried out at second-stage surgery 3, 6, 9, and 12 months later; and then annually up to 4 years after placement of the definitive restoration. The radiographic examination was conducted by means of a standardized procedure to verify osseointegration. RESULTS: There was 100% attendance at the follow-up examination after 4 years. At second-stage surgery, which was performed after 4 to 6 months' healing time, none of the implants showed any signs of mobility, peri-implantitis, or bone loss. Two implants failed in the MR group, one at 3 months and one at 9 months after placement; 1 implant failed in the HA group at 4 months after placement. After 4 years, the implant success rate was 97.3% (108 of 111 implants were considered successful). The success rate did not differ significantly between the HA group (98.2%) and the MR group (96.4%). DISCUSSION: The use of larger-diameter implants served to minimize the anatomic discrepancies that would have evolved when substituting a molar with a standard-diameter implant. According to the accepted criteria for success, the 5-year success rate should be at least 85%; therefore both methods may be considered satisfactory. CONCLUSION: Implants placed in combination with a resorbable allogeneic material or with a resorbable membrane provided predictable long-term results when restored with a fixed partial denture.     

Calcium oxalate crystallization in untreated urine, centrifuged and filtered urine and ultrafiltered urine.

Centrifuged and filtered urine is often used to evaluate in vitro the crystallization processes of calcium oxalate (CaOx), but even such simple manipulations can alter the composition of the urine, as regards its protein and lipid concentrations. In urine samples taken from 17 normal male adults, we evaluated CaOx crystallization by simultaneously using three different types of urine: untreated (U), centrifuged at 2000 rpm (800 g) and filtered at 0.22 microm (CF), and centrifuged-filtered and ultrafiltered at 10 000 Da (CFU). The addition of 1.2 mmol/l of oxalate to each type of urine produced notably different results. The total amount of CaOx crystals (expressed as calcium oxalate dihydrate crystals (COD) + oxalate monohydrate crystals (COM) area/total area x 100) was on average 13.2% in U urine, 70.7% in CF urine and 11.1% in CFU urine (CF > U and CFU, U = CFU); the relative prevalence of COD and COM (expressed as COD area/COM area) was on average 71.4 in U urine, 0.0026 in CF urine and 5.5 in CFU urine (U > CF and CFU, CFU > CF); the diameter of COD (expressed in microns) was on average 15.2 in U urine, 3.7 in CF urine and 24.3 in CFU urine (CFU > U and CF, U > CF); the diameter of COM (expressed in microns) was on average 5.2 in U urine, 2.6 in CF urine and 8.9 in CFU urine (CFU > U and CF, U > CF); the total amount of CaOx aggregates (expressed as CaOxAgg area/total area x 100) was on average 8.5% in U urine, 22.1% in CF urine and 2.9% in CFU urine (CF > U and CFU, U > CF). We conclude that CaOx crystallization processes in manipulated urine are extremely different, probably due to changes in macromolecular compounds.     

Cellular cytotoxicity mediated by granule-depleted neutrophil cytoplasts

Summary Neutrophil-derived nucleus- and granule-free cytoplasts, consisting of cytosol enclosed by an intact plasma membrane, were able to destroy ⁵¹Cr-labelled ox red blood cells (ORBC) in the presence of phorbol myristate acetate (PMA). The slope of the target cell lysis vs the log of the cytoplast number was similar to that observed with neutrophils as effector cells. Nevertheless, a number of cytoplasts 60–80 times higher than that of neutrophils was required to obtain a common level of cytotoxicity. The ability of cytoplasts and neutrophils to lyse ORBC was completely abolished by catalase and unaffected by superoxide dismutase and mannitol, suggesting the involvement of hydrogen peroxide in the target cell damage. Addition of myeloperoxidase (MPO) to cytoplasts increased lysis. The MPO inhibitor azide significantly reduced the cytolysis by neutrophils, but not the cytolysis by cytoplasts, except when experiments were carried out in the presence of MPO. The results indicate that neutrophil cytosol and plasma membrane represent the basic requirement for the PMA-dependent cytolytic process, whereas MPO behaves as a device to amplify lysis.