ANALISI DEL METABOLISMO GLUCIDICO IN PAZIENTI CIRROTICI SOTTOPOSTI A TRAPIANTO EPATICO: RUOLO DELLA SECREZIONE BETA CELLULARE E DELL'INSULINORESISTENZA.

Impaired glucose metabolism is frequently described in cirrhotic patients. The pathogenesis of diabetes mellitus (DM) in this population is complex and not precisely known. Insulin resistance (IR) plays a central role in the glucose metabolism disturbance and it has been speculated that genetic and environmental factors and some etiologic agents in liver disease impair insulin secretion. Aim of the study: evaluate \u3b2 cell secretion and insulin sensitivity in a cohort of cirrhotic patients undergoing liver transplantation (LT). 107 cirrhotic patients (31 female e 76 male) were evaluated before LT. The patients who underwent LT were evaluated 3, 6, 12 months after surgery. To evaluate insulin resistance HOMA-IR was used. To assess the \u3b2 cell secretion, a state-of-art modelling of glucose/C-peptide curves during OGTT was used. Two outputs were provided: dynamic evaluation (1st phase) and proportional evaluation (2nd phase). Before LT the prevalence of DM and prediabetes (pre DM) were 50.5% and 31.8 % respectively. DM patients showed a lower insulin secretion (both 1st and 2nd phase) and tended to have higher HOMA-IR when compared to pre DM and non DM subjects. After LT glucose metabolism improved (impaired glucose metabolism: 6 months 61.1%, 12 months 65.6%). HOMA-IR was decreased (pre LT: 5.48\ub15.14, 3 months post LT: 2.17\ub11.62, 6 months post LT: 2.28\ub11.44, 12 months post LT: 2.36\ub11.73 P=0.0017). No differences in \u3b2 cell secretion was found. When the population who underwent LT was divided in 2 groups according to the improvement or not of glucose metabolism, higher insulin secretion was found in improved subjects (2nd phase). No differences in HOMA-IR, age, duration of hepatic disease, family history of type 2 DM, immunosuppressive therapy were observed. In conclusion IR and reduced insulin secretion was observed in cirrhotic diabetic patients. After LT an improved glucose metabolism was observed. Insulin sensitivity was increased in all patients and higher \u3b2 cell secretion was observed only in subjects with improved glucose metabolism

Momentum distribution of liquid helium

We have obtained the one--body density matrix and the momentum distribution $n(p)$ of liquid $^4$He at $T=3D0^o$K from Diffusion Monte Carlo (DMC) simulations, using trial functions optimized via the Euler Monte Carlo (EMC) method. We find a condensate fraction smaller than in previous calculations. Though we do not explicitly include long--range correlations in our calculations, we get a momentum distribution at long wavelength which is compatible with the presence of long--range correlations in the exact wave function. We have also studied $^3$He, using fixed--node DMC, with nodes and trial functions provided by the EMC. In particular, we analyze the momentum distribution $n(p)$ with respect to the discontinuity $Z$ as well as the singular behavior, at the Fermi surface. We also show that an approximate factorization of the one-body density matrix $\rho(r)\simeq \rho_0(r)\rho_B(r)$ holds, with $\rho_0(r)$ and $\rho_B(r)$ respectively the density matrix of the ideal Fermi gas and the density matrix of a Bose $^3$He.Comment: 10 pages, REVTeX, 12 figure

Students’ satisfaction and teaching efficiency of university offer

This study analyses the factors affecting students’ satisfaction with university experience, focusing on the aspects characterising the teaching efficiency of educational offer. For this purpose, organisation of teaching activities, available information, teaching materials, and other facilities offered to students to make their learning experience more successful, are considered as indicators of teaching efficiency. Our interest in this topic is justified by the importance that students’ satisfaction assumes, not only as indicator of the quality of educational services but also for its relationship with overall life satisfaction and subjective well-being. A structural equation model with latent variables is estimated by using survey and administrative data of the University of Pisa. Main findings seem to show that teaching efficiency has a positive effect on satisfaction and suggest that whenever it is inadequate, or at least, considered as such, students are less satisfied for their university experience. The effects of other factors on students’ satisfaction such as studies organisation, social capital and internship experience are also discussed

Nanotechnology advances towards development of targeted-treatment for obesity

Obesity through its association with type 2 diabetes (T2D), cancer and cardiovascular diseases (CVDs), poses a serious health threat, as these diseases contribute to high mortality rates. Pharmacotherapy alone or in combination with either lifestyle modifcation or surgery, is reliable in maintaining a healthy body weight, and preventing progression to obesity-induced diseases. However, the anti-obesity drugs are limited by non-specifcity and unsustainable weight loss efects. As such, novel and improved approaches for treatment of obesity are urgently needed. Nanotechnology-based therapies are investigated as an alternative strategy that can treat obesity and be able to overcome the drawbacks associated with conventional therapies. The review presents three nanotechnology-based anti-obesity strategies that target the white adipose tissues (WATs) and its vasculature for the reversal of obesity. These include inhibition of angiogenesis in the WATs, transformation of WATs to brown adipose tissues (BATs), and photothermal lipolysis of WATs. Compared to conventional therapy, the targeted-nanosystems have high tolerability, reduced side efects, and enhanced efcacy. These efects are reproducible using various nanocarriers (liposomes, polymeric and gold nanoparticles), thus providing a proof of concept that targeted nanotherapy can be a feasible strategy that can combat obesity and prevent its comorbiditie

Differential scanning calorimetry of erythrocyte reconstituted membrane

The thermal properties of biomembranes examined by d\uedfferential calorimetry mimic the properties of b\uedlayers formed from their isolated lipids or from synthetic lipids. In this study we have analyzed, by differential scanning calorimetry (DSC), the thermal behaviour of lipids extracted from bovine erythrocyte and of their reconst\uedtuted mixtures. Membrane lipids were extracted from blood samples of 11 cows and separated in the three components: cholesterol, phospholipids and glycolipids. Phospholipid and glycolipid classes were determined by thin layer chromatography. Lipids from erythrocyte membrane of different animals (at controlled diet), at a given time, were pooled together at a proportional amount like in the original membranes. DSC was performed on aqueous buffer dispersions (pH 7.4) of the average lipid components but, \uedn some cases, the sample contained lipids \uedsolated from one animal. Average phospholipid sample exhibited two phase transitions: the first at 24 - 26 \ub0C and the second at about 38 \ub0C. Some scans of phosphol\uedpids from one animal show only the first trans\uedt\uedon which occurs between 23.1 and 25.4 \ub0C whereas the second phase transition, when occurring, is at very different temperatures (32.4 - 38.1 \ub0C). For all average glycolipid samples one transition was observed at about 35 \ub0C. Mixtures of cholesterol and phospholipids show only one broad transition. In these m\uedxtures the transition temperature is close to that of the second transition of phospholipid samples. Some correlations between the transition temperatures and the amounts of different phospholipids in the samples have been tested but it seems important to consider the fatty acid composition of the studied m\uedxtures to account for the different levels of saturated and unsaturated fatty acids

The thermotropic behaviour of red blood cell membrane phospholipids

Phospholipids are the major constituents of biological membranes and the lipid structural organization is important to membrane function. In this study we have examined, by differential scanning calorimetry (DSC), the thermal behaviour of phospholipids extracted from bovine red blood cell membrane and related the observed characteristics to the phospholipid classes in the mixture. Phosphol\uedp\uedd classes were separated by thin layer chromatography. DSC was performed on aqueous buffer dispersions (pH 7.4) approx. 3 mM. For all phospholipid samples at least one, or sometimes two transitions were observed. The calorimetric scans show the presence of a broad transition between 0 and 30 \ub0C (midpoint of the transition at 24.1 - 24.5 \ub0C) whereas the second phase transition occurs at a transition temperature of 32.4 - 38.1 \ub0C. The analyzed membranes contained the same amounts of phosphatidylcholine (PC; 6 - 9 % w/w of total phospholipids) and phosphatidylethanolamine (PE; 24 \u2013 32 %) but different percentual contents of sphingomyelin (SM; 16 \u2013 31 %), which contributes to rigidification, and phosphatidylserine + phosphatidylinositol (PS + PI; 30 \u2013 44 %) which may be considered as fluidizers, similar to lecithin. In all the analyzed samples practically identical temperatures at the first phase transition were obtained. The second phase transition, when occurring, was at very different temperatures. No direct correlation has been found between this second phase transition and the SM/PC ratio also if variations of this ratio in artificial bilayers and biological membranes have a pronounced effect on the system properties. The second phase transition appeared in samples characterized by an high value of the (PS + PI)/PC ratio (> 5.4) and the transition temperature increased with the value of this ratio. Further investigations seem to be necessary to consider the importance of the fatty acid composition of the studied mixtures on the thermotropic behaviour

Lateral diffusion of ganglioside GM1 in phospholipid bilayer membranes.

The lateral diffusion coefficient of ganglioside GM1 incorporated into preformed dimyristoylphosphatidylcholine (DMPC) vesicles has been investigated under a variety of conditions using the technique of fluorescence photobleaching recovery. For these studies the fluorescent probe 5-(((2-Carbohydrazino)methyl)thio)acetyl) amino eosin was covalently attached to the periodate-oxidized sialic acid residue of ganglioside GM1. This labeled ganglioside exhibited a behavior similar to that of the intact ganglioside, and was able to bind cholera toxin. The lateral diffusion coefficient of the ganglioside was dependent upon the gel-liquid crystalline transition of DMPC. Above Tm the lateral diffusion coefficient of the ganglioside was 4.7 X 10(-9) cm2 s-1 (with greater than 80% fluorescence recovery). This diffusion coefficient is significantly slower than the one previously observed for phospholipids in DMPC bilayers. The addition of increasing amounts of ganglioside, up to a maximum of 10 mol %, did not have a significant effect on the lateral diffusion coefficient or in the percent recovery. At 30 degrees C, the lateral mobility of ganglioside GM1 was not affected by the presence of 5 mM Ca2+, suggesting that, at least above Tm, Ca2+ does not induce a major perturbation in the lateral organization of the ganglioside molecules. The addition of stoichiometric amounts of cholera toxin to samples containing either 1 or 10 mol % ganglioside GM1 produced only a small decrease in the measured diffusion coefficient. The fluorescence recovery after photobleaching experiments were complemented with excimer formation experiments using pyrene-phosphatidylcholine. Above the transition temperature the presence of 10 mol % ganglioside GMI induced a large decrease in the rate of excimer formation. These results also indicated that the addition of ganglioside GMI to phospholipid bilayer vesicles induces a significant restriction in the lateral mobility parameters of the lipid bilayer and that the presence of Ca2' does not have a further effect in the mobility of the probe molecules