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.

PrPC Governs Susceptibility to Prion Strains in Bank Vole, While Other Host Factors Modulate Strain Features.

Bank vole is a rodent species that shows differential susceptibility to the experimental transmission of different prion strains. In this work, the transmission features of a panel of diverse prions with distinct origins were assayed both in bank vole expressing methionine at codon 109 (Bv109M) and in transgenic mice expressing physiological levels of bank vole PrPC (the BvPrP-Tg407 mouse line). This work is the first systematic comparison of the transmission features of a collection of prion isolates, representing a panel of diverse prion strains, in a transgenic-mouse model and in its natural counterpart. The results showed very similar transmission properties in both the natural species and the transgenic-mouse model, demonstrating the key role of the PrP amino acid sequence in prion transmission susceptibility. However, differences in the PrPSc types propagated by Bv109M and BvPrP-Tg407 suggest that host factors other than PrPC modulate prion strain features. IMPORTANCE: The differential susceptibility of bank voles to prion strains can be modeled in transgenic mice, suggesting that this selective susceptibility is controlled by the vole PrP sequence alone rather than by other species-specific factors. Differences in the phenotypes observed after prion transmissions in bank voles and in the transgenic mice suggest that host factors other than the PrPC sequence may affect the selection of the substrain replicating in the animal model.

Risk of atrial fibrillation among bisphosphonate users: a multicenter, population-based, Italian study.

UNLABELLED: Bisphosphonate treatment is used to prevent bone fractures. A controversial association of bisphosphonate use and risk of atrial fibrillation has been reported. In our study, current alendronate users were associated with a higher risk of atrial fibrillation as compared with those who had stopped bisphosphonate (BP) therapy for more than 1 year. INTRODUCTION: Bisphosphonates are widely used to prevent bone fractures. Controversial findings regarding the association between bisphosphonate use and the risk of atrial fibrillation (AF) have been reported. The aim of this study was to evaluate the risk of AF in association with BP exposure. METHODS: We performed a nested case-control study using the databases of drug-dispensing and hospital discharge diagnoses from five Italian regions. The data cover a period ranging from July 1, 2003 to December 31, 2006. The study population comprised new users of bisphosphonates aged 55 years and older. Patients were followed from the first BP prescription until an occurrence of an AF diagnosis (index date, i.e., ID), cancer, death, or the end of the study period, whichever came first. For the risk estimation, any AF case was matched by age and sex to up to 10 controls from the same source population. A conditional logistic regression was performed to obtain the odds ratio with 95% confidence intervals (CI). The BP exposure was classified into current (<90 days prior to ID), recent (91-180), past (181-364), and distant past (≥365) use, with the latter category being used as a reference point. A subgroup analysis by individual BP was then carried out. RESULTS: In comparison with distant past users of BP, current users of BP showed an almost twofold increased risk of AF: odds ratio (OR) = 1.78 and 95% CI = 1.46-2.16. Specifically, alendronate users were mostly associated with AF as compared with distant past use of BP (OR, 1.97; 95% CI, 1.59-2.43). CONCLUSION: In our nested case-control study, current users of BP are associated with a higher risk of atrial fibrillation as compared with those who had stopped BP treatment for more than 1 year.

Operationalization of the physical frailty & sarcopenia syndrome: rationale and clinical implementation.

Over the years, different operational definitions have been elaborated to identify frail older persons, but none of them has received unanimous consensus. This, in turn, has hampered the clinical implementation of frailty as well as the design of targeted interventions. To overcome the current limitations in the field, a novel operationalization of physical frailty (PF) is proposed which grounds its roots in the recognition of sarcopenia as its central biological substrate. This conceptualization is based on the fact that the clinical picture of PF overlaps substantially with that of sarcopenia. The two conditions may therefore be merged into a new clinical entity, the PF & sarcopenia (PF&S) syndrome, in which muscle loss represents both the biological substrate for the development of PF and a major pathway whereby the negative health outcomes of PF occur. All of the components defining the PF&S syndrome are measurable in an objective manner, which will facilitate its incorporation into standard practice. The recognition of a precise biological substratum for PF&S (i.e., skeletal muscle decline) also opens new venues for the development of preventive and therapeutic interventions.

Assessing the risk of osteonecrosis of the jaw due to bisphosphonate therapy in the secondary prevention of osteoporotic fractures.

SUMMARY: There is evidence that the use oral bisphosphonates can lead to osteronecrosis of the jaws (ONJ). Although the occurrence of ONJ appears rare among oral bisphosphonates (BPs) users, it is important to know that it exists and can be opportunely minimized. INTRODUCTION: The purpose of this study is to evaluate the association between BPs prescribed for the secondary prevention of osteoporotic fractures and the occurrence of ONJ. METHODS: An Italian record linkage claims database with a target population of around 18 million individuals (6 million over 55 years of age) constituted the data source. We conducted a nested case-control study within a cohort of individuals aged 55+ years old, who were discharged from hospitals with a primary diagnosis of incident osteoporotic fracture. The date related to the discharge diagnosis of ONJ was the index date. Conditional logistic regression for matched data was fitted to estimate the odds ratio (OR) along with 95 % confidence intervals (95 % CI) for the likely association between use of BPs and the risk of ONJ. RESULTS: Any one of the 61 ascertained cases of ONJ (incidence rate, 36.6 per 100,000 person-years) was matched to 20 controls for a total of 1120 controls. When the exposure to BPs was modeled according to recency (i.e., exposure time window prior to the index date) of use, the adjusted OR (95 % CI) for current users was 2.8 (1.3-5.9) against never users. The cumulative use of BPs has shown to increase the incidence of ONJ among patients with primary osteoporotic fractures, although not statistically significant risk has been observed. CONCLUSIONS: Although the risk of BP-related ONJ appears low in non-oncological indications, it is important to be aware that it exists and to know how it may be predicted and possibly minimized.

Subthreshold depression in older subjects: an unmet therapeutic need.

Major depression, defined according to DSM IV TR criteria, is less common in older subjects, while other types of depression are two to three times more prevalent. This heterogeneous group of disturbances has received different names: depression not otherwise specified, minor depression, subthreshold or subsyndromal depression. Moreover, each condition has been defined using heterogeneous criteria by different authors. The term of subthreshold depression will be adopted in this position statement. Subthreshold depression has been associated with the same negative consequences of major depression, including reduced well being and quality of life, worsening health status, greater disability, increased morbidity and mortality. Nevertheless, there is a dearth of clinical trials in this area, and therefore older patients with subthreshold depression are either not treated or they are treated with the same non pharmacological and pharmacological therapies used for major depression, despite the lack of supporting scientific evidence. There is an urgent need to reach a consensus concerning the diagnostic criteria for subthreshold depression as well as to perform clinical trials to identify effective and safe therapies in this too long neglected patient group.

Microbiological quality assessment of sand and water from three selected beaches of South Coast, São Paulo State, Brazil.

This study aimed to assess the sanitary quality of water, and wet and dry sand from three beaches located in the South Coast region of São Paulo State, Brazil, selected taking into account the frequency of tourists and the water quality (good, fair and poor). Thirty-six water samples each of wet and dry sand and seawater were collected monthly over a period of one year and analyzed for fecal indicator bacteria (FIB: thermotolerant coliforms, Escherichia coli, and enterococci), presumptive Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans and dermatophytes. The results revealed FIB concentrations more elevated in dry sand followed by wet sand and water. P. aeruginosa and presumptive S. aureus were detected with a similar frequency in water and sand samples, but maximum concentrations and geometric means were higher in dry sand. C. albicans was detected only in water samples whereas the dermatophyte Microsporum sp. was isolated exclusively from dry and wet sand samples. This evaluation showed also that the environment had a significant influence on P. aeruginosa but not on presumptive S. aureus concentrations. According to threshold values proposed in the literature for E. coli and enterococci dry sand densities, none of the beaches would be considered of sufficient quality for recreational activities.

M2 muscarinic receptors inhibit cell proliferation in human glioblastoma cell lines.

AIMS: In the present work we investigated the expression of M2 muscarinic receptor subtype in two glioblastoma cell lines and its role in the control of cell proliferation. MAIN METHODS: The M2 receptor transcript and protein expression was studied using RT-PCR and western blot analysis. (3)[H]-thymidine incorporation was used to evaluate cell proliferation in the presence or in the absence of M(2) agonist arecaidine. KEY FINDINGS: We demonstrated that M(2) receptor is expressed in both cell lines, although U251 cells show a higher expression level, compared to U87 cells. The activation of M(2) receptors by the agonist arecaidine decreases cell growth in a dose and time dependent manner. The anti-proliferative effect of arecaidine is also confirmed by the significant decrease of (3)[H]-thymidine incorporation in both cell lines. Moreover the M2 antagonist gallamine counteracts the arecaidine effects confirming M2 receptor involvement in glioma cell growth inhibition. SIGNIFICANCE: These data suggest a role for M2 receptors in the inhibition of glioma cell proliferation and the possibility of exploiting these receptors as new promising tools for glioblastoma therapy.

Nutrition in the age-related disablement process.

The transition from independence to disability in older adults is characterized by detectable changes in body composition and physical function. Epidemiologic studies have shown that weight loss, reduced caloric intake and the reduced intake of specific nutrients are associated with such changes. The mechanisms underlying these associations remain unclear, and different hypotheses have been suggested, including the reduction of the antioxidant effects of some nutrients. Changes in muscle mass and quality might play a central role in the pathway linking malnutrition, its biological and molecular consequences, and function. A different approach aims at assessing diets by dietary patterns, which capture intercorrelations of nutrients within a diet, rather than by selective foods or nutrients: epidemiologic evidence suggests that some types of diet, such as the Mediterranean diet, might prevent negative functional outcomes in older adults. However, despite a theoretical and empirical basis, intervention studies using nutritional supplementation have shown inconclusive results in preventing functional impairment and disability. The present work is the result of a review and consensus effort of a European task force on nutrition in the elderly, promoted by the International Association of Gerontology and Geriatrics (IAGG) European Region. After the critical review of different aspects related to the role of nutrition in the transition from independence to disability, we propose future lines for research, including the determination of levels of inadequacy and target doses of supplements, the study of interactions (between nutrients within a diet and with other lifestyle aspects), and the association with functional outcomes.

Is suboptimal prescribing a risk factor for poor health outcomes in community-dwelling elders? The ICARe Dicomano study.

PURPOSE: Mostly because of comorbidity and drugs consumption, older persons are often exposed to an increased risk of sub-optimal prescribing (SP). At present, few studies investigated the association between SP and long-term health outcomes. We examined the relation between SP and the risk of mortality and hospitalization in Italian older community-dwellers. METHODS: Older (65+ years) community-dwelling residents of a small town in Tuscany were enrolled in a longitudinal study. SP was defined as polypharmacy (use of 5+ drugs), prescription of inappropriate drugs (ID) according to Beers' criteria, and of potentially interacting drugs (PID), evaluated in 1995 and 1999. These three forms of SP were entered as time-dependent exposures into multivariable Cox regression analysis models, whose outcomes were mortality and hospitalizations through 2003. RESULTS: Of 1022 participants (mean age 73.0 +/- 6.8, 57% women), 220 were evaluated in 1995, 234 in 1999 and 568 in both waves. In univariate analysis, mortality was two-fold higher in participants with polypharmacy (73.4/1000 person/years, 95% CI 58.2-92.4 vs. 34.1, 95% CI 29.7-39.2; p < 0.001) or PID (72.7/1000 person/years, 95% CI 46.3-113.9 vs. 38.0, 95% CI 33.5-43.1; p < 0.001), whereas it was unrelated to the presence of ID. Hospitalization rates were independent of any form of SP. In multivariable models, polypharmacy, ID, and PID were no longer associated with an increased risk of death, and ID predicted a slightly increased risk of hospitalizations (HR 1.03, 95% CI 1.0-1.06, p = 0.048). CONCLUSIONS: In this cohort, SP was not associated with an excess risk of poor health outcomes.

Elastic incoherent neutron scattering as a probe of high pressure induced changes in protein flexibility.

We report here the results of elastic incoherent neutron scattering experiments on three globular proteins (trypsin, lysozyme and beta-lactoglobulin) in different pressure intervals ranging from 1 bar to 5.5 kbar. A decrease of the mean square hydrogen fluctuations, u(2), has been observed upon increasing pressure. Trypsin and beta-lactoglobulin behave similarly while lysozyme shows much larger changes in u(2). This can be related to different steps in the denaturing processes and to the high propensity of lysozyme to form amyloids. Elastic incoherent neutron scattering has proven to be an effective microscopic technique for the investigation of pressure induced changes in protein flexibility.

Msx2 induces epithelial-mesenchymal transition in mouse mammary epithelial cells through upregulation of Cripto-1.

Epithelial-mesenchymal transition (EMT) is a process occurring during both embryogenesis and early stages of invasive cancer. Epithelial cells that undergo EMT become more migratory and invasive with a mesenchymal morphology. Herein we assess EMT induction in a mouse mammary epithelial cell line driven by Msx2, a homeobox-containing transcription factor important during mammary gland development. NMuMG cells, a normal mouse mammary epithelial cell line, stably transfected with a Msx2 cDNA showed downregulation of an epithelial marker E-cadherin and upregulation of the mesenchymal markers vimentin and N-cadherin. Furthermore, overexpression of Cripto-1, a member of the epidermal growth factor-CFC protein family already known to be involved in EMT, was detected in Msx2-transfected cells. The expression of Cripto-1 was accompanied by activation of the tyrosine kinase c-Src pathway and an increase in the invasive ability of the cells. Functional assays also demonstrated inhibition of the invasive behavior of the Msx2-transfected cells by a c-Src specific inhibitor. Moreover, immunohistochemistry of human infiltrating breast carcinomas showed positive staining for Msx2 only in the infiltrating tumor cells while the non-infiltrating tumor cells were negative. These results suggest that Msx2 may play a significant role in promoting EMT in epithelial cells that acquire properties involved in tumor invasion. J. Cell. Physiol. 219: 659-666, 2009. Published 2009 Wiley-Liss, Inc.

Structure of self-organized multilayer nanoparticles for drug delivery.

The combined use of cryo-TEM, dynamic light scattering, and small-angle X-ray and neutron scattering techniques allows a detailed structural model of complex pharmaceutical preparations of soybean lecithin/chitosan nanoparticles used as drug vectors to be worked out. Charge-driven self-organization of the lipid(-)/polysaccharide(+) vesicles occurs during rapid injection, under mechanical stirring, of an ethanol solution of soybean lecithin into a chitosan aqueous solution. We conclude that beyond the charge inversion region of the phase diagram, i.e., entering the redissolution region, the initial stages of particle formation are likely to be affected by a re-entrant condensation effect at the nanoscale. This behavior resembles that at the mesoscale which is well-known for polyion/amphiphile systems. Close to the boundary of the charge inversion region, nanoparticle formation occurs under a maximum condensation condition at the nanoscale and the complexation-aggregation process is driven toward a maximum multilamellarity. Interestingly, the formulation that maximizes vesicle multilamellarity corresponds to that displaying the highest drug loading efficiency.

A cell line infectible by prion strains from different species.

It has been shown previously that ovine prion protein (PrP(C)) renders rabbit epithelial RK13 cells permissive to the multiplication of ovine prions, thus providing evidence that species barriers can be crossed in cultured cells through the expression of a relevant PrP(C). The present study significantly extended this observation by showing that mouse and bank vole prions can be propagated in RK13 cells that express the corresponding PrP(C). Importantly, the respective molecular patterns of abnormal PrP (PrP(res)) and, where examined, the neuropathological features of the infecting strains appeared to be maintained during the propagation in cell culture. These findings indicate that RK13 cells can be genetically engineered to replicate prion strains faithfully from different species. Such an approach may facilitate investigations of the molecular basis of strain identity and prion diversity.

Quantitative profiling of the pathological prion protein allotypes in bank voles by liquid chromatography-mass spectrometry.

The conversion of the cellular prion protein (PrP(C)) into a misfolded isoform (PrP(TSE)) that accumulates in the brain of affected individuals is the key feature of transmissible spongiform encephalopaties (TSEs). Susceptibility to TSEs is influenced by polymorphisms of the prion gene suggesting that the presence of certain amino acid residues may facilitate the pathological conversion. In this work, we describe a quantitative, fast and reliable HPLC-MS method that allowed to demonstrate that in the brain of 109(Met/Ile) heterozygous bank voles infected with the mouse adapted scrapie strain 139A, there are comparable amounts of PrP(TSE) with methionine or isoleucine in position 109, suggesting that in this TSE model the two allotypes have similar rates of accumulation. This method can be easily adapted for the quantitative determination of PrP allotypes in the brain of other natural or experimental TSE models.

Formation of self-organized nanoparticles by lecithin/chitosan ionic interaction.

In this work the production of auto-assembled nanoparticles obtained by the mixing of chitosan and lecithin is presented. The size and surface charge of the nanoparticles were studied as function of the weight ratio between components, the viscosity of the polysaccharide and the pH of the colloidal suspension. In order to elucidate the structure of nanoparticles, micro-FT-IR and elastic neutron scattering experiments have been performed. Results evidenced a strong electrostatic interaction between components and a structure that is neither that of homogeneous spheres nor of coated unilamellar vesicles. Preliminary encapsulation experiments with progesterone, as model lipophilic drug, showed good encapsulation efficiencies.

Synchronous colon and gastric advanced carcinomas.

An unusual case of advanced synchronous colon and gastric carcinoma is described. A 36 year old female was admitted to our Department with a stenosing right colon cancer diagnosed at endoscopy which was performed for lower crampy abdominal pain and gross blood in the stool. Multiple colon polyps, distal to the tumor, were also detected. On preoperative abdominal computed tomography, a stenosing right colon cancer, without evidence of abdominal diffusion, was confirmed. At laparotomy, in addition to colon cancer, an antral gastric cancer was incidentally found. En bloc hemigastrectomy and subtotal colectomy were performed. Digestive continuity was restored by gastrojejunal and ileosigmoid anastomoses. At histology, a poorly differentiated gastric adenocarcinoma with signet ring-cell component (pT2, pN0; stage IB) and a moderately differentiated colon adenocarcinoma with a tubulovillous component (pT3, pN1; stage III, Stage Dukes C) were revealed. Both tumors showed a low expression of p53 and c-erb2 oncoproteins. No genetic defect was identified in the APC and MMR genes. The patient is alive, without recurrence, two years after the operation.

QENS investigation of the dynamics of starch saccharides.

We present here quasi-elastic neutron scattering results on D20 hydrated samples of amylose, one of the main saccharide components of starch. Two different sample hydrations (h = 0.5 and 1.0 g D2O (g dry amylose)-1 have been investigated in the temperature range 170 to 350 K. Below 260 K only an elastic contribution is present in the spectra, while a quasi-elastic component shows up above this temperature. The elastic incoherent structure factor (EISF) associated with this component changes considerably with increasing temperature. For the sample with hydration h = 0.5 the confinement volume increases by a factor of four in going from 300 to 350 K, and the proportion of hydrogen involved in the confined diffusion motion increases as well from 30 to 55%. Similar effects are observed at the higher hydration investigated. The observed dynamics can be associated with the known plasticising role of water in polysaccharides.

Lymphadenectomy in gastric cancer: influence on prognosis of lymph node count.

To better understand the role of the number of lymph nodes retrieved on long-term outcome of gastric cancer treatment, 154 patients who had undergone curative resection, with dissection of >15 nodes were retrospectively studied. Dissection of perigastric and extraperigastric lymph nodes, defined as 'extended' (>26 nodes dissected) in 39 cases and 'limited' (< or = 26 nodes dissected) in 115 cases, was performed. A total of 3479 lymph nodes (mean 22.6 per specimen), were dissected and of these 721 showed metastases. A mean of 8.1 lymph node metastases, per metastatic case, was found. Regression analysis showed no independent factor associated with the extent of lymphadenectomy. Depth of wall invasion (p=0.000) and histological growth pattern (p=0.044) were independently associated with the number of lymph nodes involved (pN0, pN1 1-7, pN2 >7). The cumulative 5-year survival rate was 47% in patients without lymph node metastases; 29% in those with 1-7 nodes involved and 17% in those with >8 nodes involved (p=0.002). Receiver operating characteristic (ROC) curve analysis, in 65 nodenegative cancer cases, demonstrated an area under the curve for vital status (alive or dead) of 0.602 (95% CI: 0.473 - 0.721). All node-negative cases with a number equivalent to or exceeding the cutoff point of 23 nodes were alive. ROC analysis showed 11 to be the cutoff number of metastasized lymph nodes in correlation with vital status. Almost all those patients in whom the number of positive nodes was equivalent to, or exceeded the cutoff point had died (area under the ROC curve 0.633; 95% CI: 0.524 - 0.733). ROC analysis showed that the cutoff lymph node ratio, in relation to vital status, was 0.33. The majority of patients at or above this cutoff point had died (area under ROC curve 0.682; 95% CI: 0.574 - 0.776). Multivariate survival analysis showed that lymph node ratio was the only independent prognostic factor (p=0.001). The present findings suggest that, in lymphadenectomy with at least 15 nodes, the number and status of regional nodes dissected, irrespective of the location, provide reliable prognostic information on curatively resected gastric carcinomas.