Inter-relationships among psychopathology, cognition, and real-life functioning in early and late phase schizophrenia: A network analysis approach.

Many illness-related factors contribute to the reduction of the real-life functioning observed in people with schizophrenia (SZ). These include the psychopathological dimensions of the disorder such as positive, negative, disorganization, and depressive symptoms as well as impairment in neurocognition, social cognition, and metacognition. The associations between some of these variables change with the duration of illness (DOI), but this aspect was not explored with a network approach. This study aimed at describing and comparing the inter-relationships between psychopathological, cognitive, and functioning variables in early (DOI ≤ 5 years) and late (DOI > 5 years) phase SZ with network analyses and at assessing which variables were more strictly and directly associated with the real-life functioning. A network representation of the relationships between variables and the calculation of centrality indices were performed within each group. The two groups were compared with a network comparison test. Seventy-five patients with early and ninety-two with late phase SZ were included. No differences in the global network structure and strength were found between the two groups. In both groups, visual learning and disorganization exhibited high centrality indices and disorganization, negative symptoms, and metacognition were directly and strongly associated with real-life functioning. In conclusion, regardless of the DOI, a rehabilitation aimed at improving visual learning and disorganization (i.e., the most central variables) might reduce the strength of the associations that compose the network and therefore indirectly facilitate functional recovery. Simultaneously, therapeutic interventions targeting disorganization and metacognition might directly improve real-life functioning.

Polymeric micelles in drug delivery: An insight of the techniques for their characterization and assessment in biorelevant conditions.

Polymeric micelles, i.e. aggregation colloids formed in solution by self-assembling of amphiphilic polymers, represent an innovative tool to overcome several issues related to drug administration, from the low water-solubility to the poor drug permeability across biological barriers. With respect to other nanocarriers, polymeric micelles generally display smaller size, easier preparation and sterilization processes, and good solubilization properties, unfortunately associated with a lower stability in biological fluids and a more complicated characterization. Particularly challenging is the study of their interaction with the biological environment, essential to predict the real in vivo behavior after administration. In this review, after a general presentation on micelles features and properties, different characterization techniques are discussed, from the ones used for the determination of micelles basic characteristics (critical micellar concentration, size, surface charge, morphology) to the more complex approaches used to figure out micelles kinetic stability, drug release and behavior in the presence of biological substrates (fluids, cells and tissues). The techniques presented (such as dynamic light scattering, AFM, cryo-TEM, X-ray scattering, FRET, symmetrical flow field-flow fractionation (AF4) and density ultracentrifugation), each one with their own advantages and limitations, can be combined to achieve a deeper comprehension of polymeric micelles in vivo behavior. The set-up and validation of adequate methods for micelles description represent the essential starting point for their development and clinical success.

inPentasomes: An innovative nose-to-brain pentamidine delivery blunts MPTP parkinsonism in mice.

Preclinical and clinical evidences have demonstrated that astroglial-derived S100B protein is a key element in neuroinflammation underlying the pathogenesis of Parkinson's disease (PD), so much as that S100B inhibitors have been proposed as promising candidates for PD targeted therapy. Pentamidine, an old-developed antiprotozoal drug, currently used for pneumocystis carinii is one of the most potent inhibitors of S100B activity, but despite this effect, is limited by its low capability to cross blood brain barrier (BBB). To overcome this problem, we developed a non-invasive intranasal delivery system, chitosan coated niosomes with entrapped pentamidine (inPentasomes), in the attempt to provide a novel pharmacological approach to ameliorate parkinsonism induced by subchronic MPTP administration in C57BL-6 J mice. inPentasomes, prepared by evaporation method was administered daily by intranasal route in subchronic MPTP-intoxicated rodents and resulted in a dose-dependent manner (0.001-0.004 mg/kg) capable for a significant Tyrosine Hydroxylase (TH) positive neuronal density rescue in both striatum and substantia nigra of parkinsonian mice. In parallel, inPentasomes significantly decreased the extent of glial-related neuroinflammation through the reduction of specific gliotic markers (Iba-1, GFAP, COX-2, iNOS) with consequent PGE2 and NO2- release reduction, in nigrostriatal system. inPentasomes-mediated S100B inhibition resulted in a RAGE/NF-κB pathway downstream inhibition in the nigrostriatal circuit, causing a marked amelioration of motor performances in intoxicated mice. On the basis of our results, chitosan coated niosomes loaded with pentamidine, the inPentasome system, self-candidates as a promising new intranasal approach to mitigate parkinsonism in humans and possibly paves the way for a possible clinical repositioning of pentamidine as anti-PD drug.

Directional K+ channel insertion in a single phospholipid bilayer: Neutron reflectometry and electrophysiology in the joint exploration of a model membrane functional platform.

We investigated the insertion of small potassium (K+) channel proteins (KcvMA-1D and KcvNTS) into model membranes and the lipid-protein structural interference, combining neutron reflectometry and electrophysiology. Neutron reflectometry experiments showed how the transverse structure and mechanical properties of the bilayer were modified, upon insertion of the proteins in single model-membranes, either supported on solid substrate or floating. Parallel electrophysiology experiments were performed on the same channels reconstituted in free-standing planar lipid bilayers, of both typical composition and matched to the neutron reflectometry experiment, assessing their electrical features. Functional and structural results converge in detecting that the proteins, conical in shape, insert with a directionality, cytosolic side first. Our work addresses the powerful combination of the two experimental approaches. We show here that membrane structure spectroscopy and ion channel electrophysiology can become synergistic tools in the analysis of structural-functional properties of biomimetic complex environment.

Water response to ganglioside GM1 surface remodelling.

BACKGROUND: Gangliosides are biological glycolipids participating in rafts, structural and functional domains of cell membranes. Their headgroups are able to assume different conformations when packed on the surface of an aggregate, more lying or standing. Switching between different conformations is possible, and is a collective event. Switching can be induced, in model systems, by concentration or temperature increase, then possibly involving ganglioside-water interaction. In the present paper, the effect of GM1 ganglioside headgroup conformation on the water structuring and interactions is addressed. METHODS: Depolarized Rayleigh Scattering, Raman Scattering, Quasielastic Neutron Scattering and NMR measurements were performed on GM1 ganglioside solutions, focusing on solvent properties. RESULTS: All used techniques agree in evidencing differences in the structure and dynamics of solvent water on different time-and-length scales in the presence of either GM1 headgroup conformations. CONCLUSIONS: In general, all results indicate that both the structural properties of solvent water and its interactions with the sugar headgroups of GM1 respond to surface remodelling. The extent of this modification is much higher than expected and, interestingly, ganglioside headgroups seem to turn from cosmotropes to chaotropes upon collective rearrangement from the standing- to the lying-conformation. SIGNIFICANCE: In a biological perspective, water structure modulation could be one of the physico-chemical elements contributing to the raft strategy, both for rafts formation and persistence and for their functional aspects. In particular, the interaction with approaching bodies could be favoured or inhibited or triggered by complex-sugar-sequence conformational switch. This article is part of a Special Issue entitled "Science for Life" Guest Editor: Dr. Austen Angell, Dr. Salvatore Magazù and Dr. Federica Migliardo.

Neutrons for rafts, rafts for neutrons.

The determination of the structure of membrane rafts is a challenging issue in biology. The selection of membrane components both in the longitudinal and transverse directions plays a major role as it determines the creation of stable or tunable platforms that host interactions with components of the outer environment. We focus here on the possibility to apply neutron scattering to the study of raft mimics. With this aim, we realized two extreme experimental models for the same complex membrane system (phospholipid : cholesterol : ganglioside GM1), involving two of the characteristic components of glycolipid-enriched rafts. One consists of a thick stack of tightly packed membranes, mixed and symmetric in composition, deposited on a silicon wafer and analyzed by neutron diffraction. The other consists of a free floating individual membrane, mixed and asymmetric in composition in the two layers, studied by neutron reflection. We present here results on the ganglioside-cholesterol coupling. Ganglioside GM1 is found to force the redistribution of cholesterol between the two layers of the model membranes. This causes cholesterol exclusion from compositionally symmetric ganglioside-containing membranes, or, alternatively, asymmetric cholesterol enrichment in raft-mimics, where gangliosides reside into the opposite layer.

Ganglioside GM1 forces the redistribution of cholesterol in a biomimetic membrane.

Neutron reflectivity has been applied to investigate different mixed asymmetric lipid systems, in the form of single "supported+floating" bilayers, made of phospholipids, cholesterol and GM1 ganglioside (Neu5Acα2-3(Galß1-3GalNAcß1-4)Galß1-4Glcß1Cer)) in bio-similar mole ratios. Bilayer preparation was carried out layer-by-layer with the Langmuir-Blodgett Langmuir-Schaefer techniques, allowing for compositional asymmetry in the system buildup. It is the first time that such a complex model membrane system is reported. Two important conclusions are drawn. First, it is experimentally shown that the presence of GM1 enforces an asymmetry in cholesterol distribution, opposite to what happens for a GM1-free membrane that, submitted to a similar procedure, results in a full symmetrization of cholesterol distribution. We underline that natural cholesterol has been used. Second, and most interesting, our results suggest that a preferential asymmetric distribution of GM1 and cholesterol is attained in a model membrane with biomimetic composition, revealing that a true coupling between the two molecular species occurs.

Lamellar stacking split by in-membrane clustering of bulky glycolipids.

We developed a simple model to investigate the effect of lipid clustering on the local interlayer distance in a cluster of interacting lamellae. The model, based on nonequilibrium thermodynamics and linear stability theories, explores the early stages of the lamella-lamella phase separation process where the lateral diffusion is much faster than the interlamellar lipid exchange. Results indicate, in the early stages, the presence of locally distorted regions with a higher concentration of one lipid component and an anomalous repeat distance. Experimental cases are presented, consisting of multilamellar-oriented depositions of phospholipids containing minority amounts of ganglioside or sphingomyelin under a low-hydration condition. The minority components are known to form domains within the phospholipid bilayer matrix. The low water content inhibits the lipid exchange among nearby lamellae and strengthens lamella-lamella interaction, allowing for a straightforward comparison with the model. Small-angle and wide-angle neutron diffraction experiments were performed in order to detect interlayer distances and local chain order, respectively. Lamellar stacking splitting has been observed for the ganglioside-containing lamellae, induced by in-phase lipid clustering. In excess water and after long equilibration times, these local structures may further evolve, leading to coexisting lamellar phases with different lipid compositions and interlayer distances.

Intermicellar interactions may induce anomalous size behavior in micelles carrying out bulky heads with multiple spatial arrangements.

We report experimental and theoretical results on the concentration dependence of the micellar size of GM1 and GM1acetyl gangliosides, five-sugar-headed anionic glycolipids. Contrary to one of the mainstays of colloid science, that the aggregation number of amphiphile aggregates grows with concentration, an anomalous region is found at intermediate concentrations, where a sharp decrease of the aggregation number occurs. Experiments were performed by small-angle X-ray and neutron scattering (SAXS and SANS). Two models are discussed, reproducing the observed behavior of either GM1acetyl or GM1. The first one is a conventional picture of interacting micelles where a reduction in the molecular surface area, leading to an increase of the aggregate dimension, is paid to reduce intermicellar interactions: it foresees a monotonous increase of the aggregation number with concentration. The second one accounts for a conformational bistability of the bulky headgroups of GM1, modifying the amphiphilic molecular surface area and protrusion from the aggregate surface, and contributing to the inter- and intramicellar interaction balance. Energy minimization leads to a complex behavior of the aggregation number, which is consistent with the anomalous behavior of GM1.

DC(13)PC bilayers from anomalous swelling to main transition: an X-ray scattering investigation.

We have performed small-angle (SAXS) and wide-angle X-ray scattering (WAXS) measurements on the lamellar phase and on large unilamellar vesicles (LUVs) of DC(13)PC in the temperature range corresponding to the anomalous swelling regime of multibilayer systems, adjacent to the chain melting transition, and across the transition. Our SAXS measurements indicate that on cooling from the L(alpha) phase, a uniform progressive swelling of the lamellar system to anomalous distances, starting approximately 2 degrees C above the main transition, is followed by a region of coexistence, covering the width of the transition ( approximately 0.6 degrees C). Across the transition region, a progressively increasing volume fraction of gel phase with a constant P (beta') interlamellar distance coexists with a decreasing amount of nongel phase that keeps on swelling to longer distances. Along both the swelling and the transition regions, anomalies in the specific heat are observed revealing a two-step process. Simultaneous WAXS experiments show a progressive "density" increase along the swelling region, constituting a direct spectroscopic evidence of an "evolving membrane" approaching the transition in a bulk real system. Calorimetric and densitometric measurements on LUVs are also presented, together with WAXS results, that show the existence of a double step main transition in a single component nanosized closed bilayer.

Experimental evidence of a temperature-related conformational change of the hydrophilic portion of gangliosides.

The present paper reports the experimental observation of an interesting thermodynamic process which could be biologically important: such behaviour, shown by some gangliosides, is likely to be peculiar of these glycosidic compounds as it has never been observed for other membrane-type amphiphilic molecules. In water solution, gangliosides have been found to present a bistable behaviour between two stable states (called A and B) which does not involve any change in the primary structure of the molecule. The interconversion between state A and state B, and vice versa, does not occur spontaneously, but has to be triggered by some external agent, which makes this system a potentially regulated process with important biological correlations. In the present experiments, state B is reached from state A with a temperature rise in the range 30-55 degrees C. The new state is stable regardless of any possible temperature cycle. The initial state A is then regained when the ganglioside solution is dried and the solute is redissolved. The two states are believed to correspond to two different conformations of the hydrophilic portion of the molecule. The bistable behaviour is shown by the gangliosides GM2, GM1, GD1a, GD1b and Fuc-GD1b, GT1b, however, does not show such an effect.

The role of spontaneous portosystemic shunts in the course of orthotopic liver transplantation.

Spontaneous portosystemic shunts are commonly found in cirrhotic patients. Not yet established is their role after orthotopic liver transplantation (OLTx), especially when an increase in portal pressure develops, as during early acute rejection. In this study, 34 cirrhotic patients in a series of 70 OLTx are considered. Each patient had preoperative angiographic assessment, and, in 21 (62%), large spontaneous portosystemic shunts were evident. In 12 cases the shunts were not affected by the surgical procedure and were present during the postoperative period; in 9 the hepatectomy itself involved interruption of the shunts. The patient population was divided into two groups: patients with postoperative shunts (n = 12) and those without (n = 22). The two groups were similar in age, sex, Child's stage, transplantation variables, and number and grade of rejection episodes. However, mean transaminases (AST) values in the first 2 weeks were significantly higher levels in shunt versus nonshunt patients (421 +/- 335 vs 183 +/- 126; P less than 0.025), and this was even more evident when rejection occurred (626 +/- 375 vs 195 +/- 129; P less than 0.001). Furthermore, during an acute rejection reaction, three cases showed a true "steal phenomenon" through the large reopened shunts with ischemic damage to the grafts. The data indicate a possible detrimental effect of the spontaneous shunts on graft perfusion and suggest the prophylactic surgical interruption of the residual shunts during the transplantation.

Factors in the development of a liver transplantation programme: experience of 100 consecutive transplantations in Milan's Niguarda Hospital.

From December 1985 to December 1990, 100 liver orthotopic transplantations (OLTX) were performed in 89 adults with cirrhosis and various other liver diseases; eight patients had two transplants and three of these had three transplants. Organ perfusion was done with Eurocollins in the first 30, then with UW solution. Immunosuppressants were a combination of cyclosporin A and steroids for the first 30 patients, and then a combination of antilymphocyte globulin, azathioprine, methylprednisolone and cyclosporin A. The OLTXs were examined as a whole and also divided into two groups, one for 1985-88 and one for 1989-90. The cumulative survival was 63% after 12 months, 40% after 36 and 42 months. It was poor for the patients who received transplants between 1985 and 1988, but for the second group, survival was improved to 78% after 12 and 18 months. For neoplastic patients, overall survival was 49% after 18 months and 23% after 36 and 42 months. In the second group it was markedly better (83% after 18 months). The recurrence rate for patients surviving more than three months was 17% for hepatocellular carcinoma and 50% for cholangiocarcinoma. Five patients (38%) out of 13 HBsAg-positives before the transplant and surviving more than three months had recurrent hepatitis-B virus. The remaining eight patients are HBsAg negative at present. The improved actuarial survival for the second group is accounted for by the better surgical and intensive care given now and the methodological differences.

Biliary complications in orthotopic liver transplantation: experience with a modified technique of duct-to-duct reconstruction.

Biliary complications are described as frequent causes of morbidity during the postoperative course of orthotopic liver transplantation (OLTx), even in recent papers. The authors report here on their experience with duct-to-duct anastomosis as their method of choice for biliary reconstruction in a consecutive series of 100 OLTx in adult patients. The original technique, as described by Starzl, was modified by the authors by performing a wide, longitudinal plasty of both the donor and recipient bile ducts, joined together with two polidioxanone running sutures, producing the effect of a side-to-side anastomosis. This technique was used in all procedures, even when a significant discrepancy was evident between the ducts (n = 10). Follow-up was completed in 100% of the patients for a period of 2-40 months (mean 13.1 months). Four major complications (4%) occurred including hepatic abscesses due to ascending cholangitis, T-tube dislocation, partial occlusion by a branch of the T-tube at the anastomotic site, and disruption of the bile duct after T-tube removal. In four other patients, transient abdominal pain followed removal of the stent. Neither strictures nor fistulas were observed. Choledochocholedochostomy on a T-tube stent represents, in our experience, the technique of choice for biliary reconstruction in OLTx. The procedure, as described in the present study, proved to be safe in preventing strictures and leakages and appears to be feasible in nearly 100% of all adult patients undergoing OLTx.

Absence of brown product FFI in nondiabetic and diabetic rat collagen.

Accumulation of brown products in long-lived proteins might be an important factor in determining long-term diabetic complications. Fluorescent chromophore 2-(2-furoyl)-4-(5)-(2-furanyl)-1H-imidazole (FFI), isolated from hydrolyzed brown products synthesized in vitro, was proposed as a specific brown product responsible for functional and structural changes in long-lived proteins. In this study, an attempt was made to demonstrate by means of collision spectroscopy the presence of FFI in collagen samples taken from diabetic rats. Diabetic rat collagen samples showed mean values of absorbance per milligram of 4-hydroxy-L-proline significantly higher than those observed in nondiabetic rats, suggesting higher FFI levels. Surprisingly, all collagen samples from diabetic and nondiabetic rats gave collision spectra in which no peak diagnostic of FFI presence was observed. These data suggest that the absorbance level observed in diabetic rats is not due to the presence of FFI but to structurally related compounds, which are being investigated by means of mass spectrometry.

Reappraisal of surgical treatment of small hepatocellular carcinomas in cirrhosis: clinicopathological study of resection or transplantation.

Thirty-two patients with hepatocellular carcinoma (HCC) occurring in individuals with cirrhosis had a potentially curative surgical procedure. Twenty-two had segmental hepatic resections (HR), and 10 underwent orthotopic liver transplantation (OLTx). The diagnosis of hepatic malignancy was established in each case preoperatively, and each case was studied intraoperatively by means of sonography. Postoperatively each surgical specimen was examined pathologically with attention to the possibility of intrahepatic tumor spread. Twenty-three of the 32 patients had single small HCC lesion (less than 5 cm diameter) identified preoperatively. Sixteen of these underwent HR and seven underwent OLTx. Multiple additional neoplastic lesions were found in 19% of the 16 HR cases and in 14% of those undergoing OLTx when the resection specimens were examined pathologically. Vascular invasion was present in 43% of the OLTx patients and in 25% of the HR patients. Subtotal hepatic resection for small HCC occurring in cirrhosis has produced few long-term survivals. Both pre- and intraoperative sonography have been shown to underestimate the extent and distribution of these tumors. Based upon this experience that (1) vascular spread occurs often in HCC and (2) a high risk of postoperative hepatic failure can be expected after HR in cirrhotic individuals, OLTx is the most rational surgical procedure for such cases as it has the potential to cure.

Thromboendarterectomy (TEA) in the recipient as a major risk of arterial complication after kidney transplantation.

The authors analyze a series of 383 kidney transplantation pointing out the role of recipient's vessels atherosclerosis in the determination of vascular complication of the kidney graft. Three groups were considered. The first included 55 patients which required TEA for severe atherosclerotic lesion of the anastomosed vessels. The second group included 305 patients who didn't required TEA; the third group was of 20 patients who received a graft with multiple arteries which required more than one anastomosis. A significative higher rate of arterial complications was evident in the first group (p less than 0.001). Within this group the end to end arterial anastomosis was more frequently associated to thrombosis or stenosis than the end to side one (p less than 0.05). Kidney with multiple vessels also presented with an higher rate of complications (p less than 0.05).