Relating Molecular Dynamics Simulations to Functional Activity for Gly-Rich Membranolytic Helical Kiadin Peptides

Kiadins are in silico designed peptides with a strong similarity to diPGLa-H, a tandem sequence of PGLa-H (KIAKVALKAL) and with single, double or quadruple glycine substitutions. They were found to show high variability in their activity and selectivity against Gram-negative and Gram-positive bacteria, as well as cytotoxicity against host cells, which are influenced by the number and placing of glycine residues along the sequence. The conformational flexibility introduced by these substitutions contributes differently peptide structuring and to their interactions with the model membranes, as observed by molecular dynamics simulations. We relate these results to experimentally determined data on the structure of kiadins and their interactions with liposomes having a phospholipid membrane composition similar to simulation membrane models, as well as to their antibacterial and cytotoxic activities, and also discuss the challenges in interpreting these multiscale experiments and understanding why the presence of glycine residues in the sequence affected the antibacterial potency and toxicity towards host cells in a different manner.

Is there a rational basis for cannabinoids research and development in ocular pain therapy? A systematic review of preclinical evidence

BACKGROUND

Purpose of the present systematic review is to investigate preclinical evidence in favor of the working hypothesis of efficacy of cannabinoids in ocular pain treatment.

METHODS

Literature search includes the most relevant repositories for medical scientific literature from inception until November, 24 2021. Data collection and selection of retrieved records adhere to PRISMA criteria.

RESULTS

In agreement with a priori established protocol the search retrieved 2471 records leaving 479 results after duplicates removal. Eleven records result from title and abstract screening to meet the inclusion criteria; only 4 results are eligible for inclusion in the qualitative synthesis impeding meta-analysis. The qualitative analysis highlights the antinociceptive and anti-inflammatory efficacy of Δ8-tetrahydrocannabinol, cannabidiol and its derivative HU-308 and of new racemic CB1 allosteric ligand GAT211 and its enantiomers GAT228 and GAT229. Moreover, CB2R agonists RO6871304 and RO6871085 and CB2R ligand HU910 provide evidence of anti-inflammatory efficacy. CB2 agonist HU308 reduces of 241% uveitis-induced leukocyte adhesion and changes lipidome profile. Methodological and design issues raise concern of risk of bias and the amount of studies is too small for generalization. Furthermore, the ocular pain model used can resemble only inflammatory but not neuropathic pain.

CONCLUSIONS

The role of the endocannabinoid system in ocular pain is underinvestigated, since only two studies assessing the effects of cannabinoid receptors modulators on pain behavior and other two on pain-related inflammatory processes are found. Preclinical studies investigating the efficacy of cannabinoids in ocular inflammatory and neuropathic pain models are needed to pave the way for clinical translation.

Membrane perturbation, altered morphology and killing of Staphylococcus epidermidis upon contact with a cytocompatible peptide-based antibacterial surface

One possibility to prevent prosthetic infections is to produce biomaterials resistant to bacterial colonization by anchoring membrane active antimicrobial peptides (AMPs) onto the implant surface. In this perspective, a deeper understanding of the mode of action of the immobilized peptides should improve the development of AMP-inspired infection-resistant biomaterials. The aim of the present study was to characterize the bactericidal mechanism against Staphylococcus epidermidis of the AMP BMAP27(1-18), immobilized on titanium disks and on a model resin support, by applying viability counts, Field Emission Scanning Electron Microscopy (FE-SEM), and a fluorescence microplate assay with a membrane potential-sensitive dye. The cytocompatibility to osteoblast-like MG-63 cells was investigated in monoculture and in co-culture with bacteria. The impact of peptide orientation was explored by using N- and C- anchored analogues. On titanium, the ∼50 % drop in bacteria viability and dramatically affected morphology indicate a contact-killing action exerted by the N- and C-immobilized peptides to the same extent. As further shown by the fluorescence assay with the resin-anchored peptides, the bactericidal effect was mediated by rapid membrane perturbation, similar to free peptides. However, at peptide MBC resin equivalents the C-oriented analogue proved more effective with more than 99 % killing and maximum fluorescence increase, compared to half-maximum fluorescence with more than 90 % killing produced by the N-orientation. Confocal microscopy analyses revealed 4-5 times better MG-63 cell adhesion on peptide-functionalized titanium both in monoculture and in co-culture with bacteria, regardless of peptide orientation, thus stimulating further studies on the effects of the immobilized BMAP27(1-18) on osteoblast cells.

The Cold Case of Metabotropic Glutamate Receptor 6: Unjust Detention in the Retina?

It is a common opinion that metabotropic glutamate receptor subtype 6 (mGluR6) is expressed exclusively in the retina, and in particular in the dendrites of ON-bipolar cells. Glutamate released in darkness from photoreceptors activates mGluR6, which is negatively associated with a membrane non-selective cation channel, the transient receptor potential melanoma-related 1, TRPM1, resulting in cell hyperpolarization. The evidence that mGluR6 is expressed not only in the retina but also in other tissues and cell populations has accumulated over time. The expression of mGluR6 has been identified in microglia, bone marrow stromal and prostate cancer cells, B lymphocytes, melanocytes and keratinocytes and non-neural tissues such as testis, kidney, cornea, conjunctiva, and eyelid. The receptor also appears to be expressed in brain areas, such as the hypothalamus, cortex, hippocampus, nucleus of tractus solitarius, superior colliculus, axons of the corpus callosum and accessory olfactory bulb. The pharmacological activation of mGluR6 in the hippocampus produced an anxiolytic-like effect and in the periaqueductal gray analgesic potential. This review aims to collect all the evidence on the expression and functioning of mGluR6 outside the retina that has been accumulated over the years for a broader view of the potential of the receptor whose retinal confinement appears understimated.

Dose intercomparison at Italian hadrontherapy centers

PURPOSE

To perform the first dosimetric intercomparison for proton beams in Italy using ionization chambers, according to the IAEA TRS-398 code of practice.

METHODS

Measurement sites included: National Center for Oncological Hadron Therapy (CNAO, Pavia), Center for Proton Therapy (CTP, Trento) and Center for Hadron Therapy and for advanced Nuclear Applications (CATANA, Catania). For comparison we also included a 6 MV photon beam produced at Istituti Clinici Scientifici Maugeri (ICSM, Pavia). For proton beams, both single pseudo-monoenergetic layers (in order to obtain a planned dose of 2 Gy at the reference depth of 2 cm in a water phantom) and Spread-out Bragg peaks (SOBP) have been delivered. Measurements were performed with a PTW Farmer 30010-1 and a PTW Advanced Markus type 34,045 ionization chamber.

RESULTS

Data obtained at CATANA, CNAO and CPT in terms of absorbed dose to water depth show good consistency within the experimental uncertainties, with a weighted mean of 1.99 ± 0.01 Gy and a standard error of 0.003 Gy, with reference to a nominal dose of 2 Gy as designed by the treatment planning system.

CONCLUSIONS

The results showed a standard deviation of less than 1% for single layer and SOBP beams, for all chambers and a percent deviation less than 1.5% for single layer measurements. The weighted means of the absorbed doses for clinical proton beams (118.19 MeV and 173.61 MeV) are consistent within less than 1%. These results agree within the 1.5% difference considered acceptable for national dose intercomparison.

P14.128 Lack of development of Pneumocystis Jirovecii Pneumonia in a cohort of 103 Italian glioblastoma patients not receiving prophylaxis during post-surgical chemoradiotherapy

BACKGROUND

Patients diagnosed with high grade gliomas (HGG) usually receive surgery, radiation, temozolomide (TMZ) and corticosteroids. A major concern in patients who receive chemoradiotherapy (CRT) is the risk of developing secondary myelosuppression and a related infection during treatment. CRT may also lead to a long-lasting reduction of WBC, associated with early death from tumor progression. Among treatment-related infections, Pneumocystis Jirovecii Pneumonia (PJP) has been reported, since then, PJP prophylaxis has been required by the FDA. However, evidence for PJP during CRT is very limited limited and the rate of PJP still low.

MATERIAL AND METHODS

We did a retrospective, Institutional Review Board-approved cohort study in 103 patients (60 men and 43 women), who were consecutively diagnosed with GBM in “A. Manzoni” Hospital in Lecco during the period May 2007 to December 2013. All of these patients were treated with CRT according to the Stupp protocol without PJP prophylaxis. Haematological toxicities of CRT were assessed according to Common Terminology Criteria for Adverse Events (CTCAE, version 5.0; November 27, 2017). The objective of our study was to investigate the association between CRT and myelosuppression and we evaluated the types of infection contracted on CRT and in particular if the absence of a proper PJP prophylaxis led to an increased rate of PJP.

RESULTS

In our cohort, among 103 patients receiving CRT, 18% developed severe lymphopenia. Among all the subjects enrolled, a total of 9 patients (8.7%) had documented infectious complications during the CRT. Three patients developed community acquired pneumonia. Moreover, we documented three cases of fever without source, two urinary tract infections, one herpes zoster, one herpes simplex 1, one phlegmon and one purulent otitis. However, no one of these patients was diagnosed as PJP despite PJP prophylaxis was not given.

CONCLUSION

In conclusion, our data seem to support a lack of undisputable evidence for a favorable risk/benefit profile in the use of PJP prophylaxis for all newly diagnosed GBM patients undergoing the CRT, also considering the rate of adverse reactions (15.2%) and severe adverse reactions (around 3%, mainly leukopenia) in non-HIV adults receiving trimethoprim/sulphametoxazole for prolonged periods.

The polysaccharide extracted from the biofilm of Burkholderia multivorans strain C1576 binds hydrophobic species and exhibits a compact 3D-structure

Microorganisms often grow in communities called biofilms where cells are imbedded in a complex self-produced biopolymeric matrix composed mainly of polysaccharides, proteins, and DNA. This matrix, together with cell proximity, confers many advantages to these microbial communities, but also constitutes a serious concern when biofilms develop in human tissues or on implanted prostheses. Although polysaccharides are considered the main constituents of the matrices, their specific role needs to be clarified. We have investigated the chemical and morphological properties of the polysaccharide extracted from biofilms produced by the C1576 reference strain of the opportunistic pathogen Burkholderia multivorans, which causes lung infections in cystic fibrosis patients. The aim of the present study is the definition of possible interactions of the polysaccharide and the three-dimensional conformation of its chain within the biofilm matrix. Surface plasmon resonance experiments confirmed the ability of the polysaccharide to bind hydrophobic molecules, due to the presence of rhamnose dimers in its primary structure. In addition, atomic force microscopy studies evidenced an extremely compact three-dimensional structure of the polysaccharide which may form aggregates, suggesting a novel view of its structural role into the biofilm matrix.

Mixed Fluorinated/Hydrogenated Self-Assembled Monolayer-Protected Gold Nanoparticles: In Silico and In Vitro Behavior

Gold nanoparticles (AuNPs) covered with mixtures of immiscible ligands present potentially anisotropic surfaces that can modulate their interactions at complex nano-bio interfaces. Mixed, self-assembled, monolayer (SAM)-protected AuNPs, prepared with incompatible hydrocarbon and fluorocarbon amphiphilic ligands, are used here to probe the molecular basis of surface phase separation and disclose the role of fluorinated ligands on the interaction with lipid model membranes and cells, by integrating in silico and experimental approaches. These results indicate that the presence of fluorinated amphiphilic ligands enhances the membrane binding ability and cellular uptake of gold nanoparticles with respect to those coated only with hydrogenated amphiphilic ligands. For mixed monolayers, computational results suggest that ligand phase separation occurs on the gold surface, and the resulting anisotropy affects the number of contacts and adhesion energies with a membrane bilayer. This reflects in a diverse membrane interaction for NPs with different surface morphologies, as determined by surface plasmon resonance, as well as differential effects on cells, as observed by flow cytometry and confocal microscopy. Overall, limited changes in monolayer features can significantly affect NP surface interfacial properties, which, in turn, affect the interaction of SAM-AuNPs with cellular membranes and subsequent effects on cells.

Design, antimicrobial activity and mechanism of action of Arg-rich ultra-short cationic lipopeptides

The increasing emergence of multidrug-resistant microorganisms represents one of the greatest challenges in the clinical management of infectious diseases, and requires the development of novel antimicrobial agents. To this aim, we de novo designed a library of Arg-rich ultra-short cationic antimicrobial lipopeptides (USCLs), based on the Arg-X-Trp-Arg-NH₂ peptide moiety conjugated with a fatty acid, and investigated their antibacterial potential. USCLs exhibited an excellent antimicrobial activity against clinically pathogenic microorganisms, in particular Gram-positive bacteria, including multidrug resistant strains, with MIC values ranging between 1.56 and 6.25 μg/mL. The capability of the two most active molecules, Lau-RIWR-NH₂ and Lau-RRIWRR-NH_2, to interact with the bacterial membranes has been predicted by molecular dynamics and verified on liposomes by surface plasmon resonance. Both compounds inhibited the growth of S. aureus even at sub MIC concentrations and induced cell membranes permeabilization by producing visible cell surface alterations leading to a significant decrease in bacterial viability. Interestingly, no cytotoxic effects were evidenced for these lipopeptides up to 50–100 μg/mL in hemolysis assay, in human epidermal model and HaCaT cells, thus highlighting a good cell selectivity. These results, together with the simple composition of USCLs, make them promising lead compounds as new antimicrobials.

Mesenteric cyst and recurrent abdominal pain in a patient with Gorlin-Goltz syndrome: a case report

Gorlin-Goltz syndrome (GGS) is an infrequent autosomal do-minant multisystemic disease with complete penetrance and variable expressivity. It is estimated to have an incidence of 1:50,000 - 1:150,000 cases with a M/F = 1:1. This report describes a case of recurrent abdominal pain due to a large mesenteric cyst in a 38-year-old female patient affected by a rare disease: Gorlin-Goltz syndrome.

Antibiotic-induced microbiota perturbation causes gut endocannabinoidome changes, hippocampal neuroglial reorganization and depression in mice

The microbiota-gut-brain axis (MGBA) regulates the reciprocal interaction between chronic inflammatory bowel and psychiatric disorders. This interaction involves multiple pathways that are highly debated. We examined the behavioural, biochemical and electrophysiological alterations, as well as gut microbiota composition in a model of antibiotic-induced experimental dysbiosis. Inflammation of the small intestine was also assessed. Mice were exposed to a mixture of antimicrobials for 2weeks. Afterwards, they received Lactobacillus casei DG (LCDG) or a vehicle for up to 7days via oral gavage. Perturbation of microbiota was accompanied by a general inflammatory state and alteration of some endocannabinoidome members in the gut. Behavioural changes, including increased immobility in the tail suspension test and reduced social recognition were observed, and were associated with altered BDNF/TrkB signalling, TRPV1 phosphorylation and neuronal firing in the hippocampus. Moreover, morphological rearrangements of non-neuronal cells in brain areas controlling emotional behaviour were detected. Subsequent probiotic administration, compared with vehicle, counteracted most of these gut inflammatory, behavioural, biochemical and functional alterations. Interestingly, levels of Lachnospiraceae were found to significantly correlate with the behavioural changes observed in dysbiotic mice. Our findings clarify some of the biomolecular and functional modifications leading to the development of affective disorders associated with gut microbiota alterations.

Palmitoylethanolamide induces microglia changes associated with increased migration and phagocytic activity: involvement of the CB2 receptor

The endogenous fatty acid amide palmitoylethanolamide (PEA) has been shown to exert anti-inflammatory actions mainly through inhibition of the release of pro-inflammatory molecules from mast cells, monocytes and macrophages. Indirect activation of the endocannabinoid (eCB) system is among the several mechanisms of action that have been proposed to underlie the different effects of PEA in vivo. In this study, we used cultured rat microglia and human macrophages to evaluate whether PEA affects eCB signaling. PEA was found to increase CB2 mRNA and protein expression through peroxisome proliferator-activated receptor-α (PPAR-α) activation. This novel gene regulation mechanism was demonstrated through: (i) pharmacological PPAR-α manipulation, (ii) PPAR-α mRNA silencing, (iii) chromatin immunoprecipitation. Moreover, exposure to PEA induced morphological changes associated with a reactive microglial phenotype, including increased phagocytosis and migratory activity. Our findings suggest indirect regulation of microglial CB2R expression as a new possible mechanism underlying the effects of PEA. PEA can be explored as a useful tool for preventing/treating the symptoms associated with neuroinflammation in CNS disorders.

Identification of novel proteins binding the AU-rich element of α-prothymosin mRNA through the selection of open reading frames (RIDome)

We describe here a platform for high-throughput protein expression and interaction analysis aimed at identifying the RNA-interacting domainome. This approach combines the selection of a phage library displaying "filtered" open reading frames with next-generation DNA sequencing. The method was validated using an RNA bait corresponding to the AU-rich element of α-prothymosin, an RNA motif that promotes mRNA stability and translation through its interaction with the RNA-binding protein ELAVL1. With this strategy, we not only confirmed known RNA-binding proteins that specifically interact with the target RNA (such as ELAVL1/HuR and RBM38) but also identified proteins not previously known to be ARE-binding (R3HDM2 and RALY). We propose this technology as a novel approach for studying the RNA-binding proteome.

Predictive factors of difficult procedure in octogenarians undergoing elective laparoscopic cholecystectomy: a single center experience

AIM

To assess the feasibility and safety of laparoscopic cholecystectomy (LC) in very elderly patients with particular attention to the predicitive factors of difficulty.

PATIENTS AND METHODS

All patients aged ≥ 80 undergoing elective LC for lithiasis at our institution since 1st January 2015 to 31st December 2015 were included in the study. Exclusion criteria were: a) acute cholecystitis; b) biliary pancreatitis; c) biliary tract neoplasms; d) urgent procedure. Pre-, intra- and postoperative data were recorded.

RESULTS

During the study period, we performed 72 LC and we enrolled 17 patients aged ≥ 80 with a M:F = 5:12. Of these, 10 patients had a "difficult" cholecystectomy. In seven cases an intraoperative cholangiography (IOC) was performed. Postoperative course was regular but in two patients we had an Oddian spasm in 1st postoperative day. Female sex (p=0.03) and preoperative high level of serum amylase (p= 0.02) were significantly associated to difficult cholecystectomy in elderly patients.

CONCLUSION

LC in octogenarians is feasible and safe. However, sex and serum amylase can help the surgeon to predict a more difficult procedure in elective LC. In this group of patients an approach based on the individual risk is desirable and the patient could be referred to a multidisciplinary approach.

Multi-organ resection for locally advanced adrenocortical cancer: surgical strategy and literature review

Adrenocortical carcinoma (ACC) is a rare and aggressive endocrine malignancy with an estimated worldwide incidence of 0.5-2 per million/year. Complete surgical removal of ACC represents the current treatment of choice for this tumor. A disease-free resection margin (R0) is an important predictor of long-term survival: surgery is demanding and must be performed by a highly experienced surgical team. We report the surgical strategy adopted in a patient with locally advanced ACC and virilization to obtain a R0 resection.

Laparoscopic or open hemicolectomy for elderly patients with right colon cancer? A retrospective analysis

AIM

The aim of this study was to compare the short-term surgical outcomes of laparoscopically-assisted right hemicolectomy (LRH) and open right hemicolectomy (ORH) in elderly patients. Patients and methods-Results. Seventy-five patients underwent right hemicolectomy for cancer during the study period, with 41 patients aged ≥ 70 years old. Twenty-four patients underwent ORH and seventeen patients had a LRH (58% vs 42%).We found no differences between ORH and LRH in terms of mean operative time :89,5 minutes in open vs 80 minutes in laparoscopic group and return of bowel function (2,76 vs 2,54 days). Also the length of hospital stay did not differ significantly between the two groups (8,5 days in ORH vs 7 days in LRH - p 0,06). Postoperative morbidity was higher in ORH (25% vs 5%) though not statistically significant and the incidence of anastomotic leakage was similar between the two groups (8% vs 5%).

CONCLUSION

Laparoscopic RH in an elderly population is feasible and safe. However, we found no evidence to suggest that it is better than open RH and think that the decision regarding the method of operation should reflect surgeon expertise, patient co-morbidities and the necessity to perform extended resections.

Designing High-Affinity Peptides for Organic Molecules by Explicit Solvent Molecular Dynamics

Short peptides offer a cheap alternative to antibodies for developing sensing units in devices for concentration measurement. We here describe a computational procedure that allows designing peptides capable of binding with high affinity a target organic molecule in aqueous or nonstandard solvent environments. The algorithm is based on a stochastic search in the space of the possible sequences of the peptide, and exploits finite temperature molecular dynamics simulations in explicit solvent to check if a proposed mutation improves the binding affinity or not. The procedure automatically produces peptides which form thermally stable complexes with the target. The estimated binding free energy reaches the 13 kcal/mol for Irinotecan anticancer drug, the target considered in this work. These peptides are by construction solvent specific; namely, they recognize the target only in the solvent in which they have been designed. This feature of the algorithm calls for applications in devices in which the peptide-based sensor is required to work in denaturants or under extreme conditions of pressure and temperature.

Palmitoylethanolamide reduces pain-related behaviors and restores glutamatergic synapses homeostasis in the medial prefrontal cortex of neuropathic mice

BACKGROUND

Enhanced supraspinal glutamate levels following nerve injury are associated with pathophysiological mechanisms responsible for neuropathic pain. Chronic pain can interfere with specific brain areas involved in glutamate-dependent neuropsychological processes, such as cognition, memory, and decision-making. The medial prefrontal cortex (mPFC) is thought to play a critical role in pain-related depression and anxiety, which are frequent co-morbidities of chronic pain. Using an animal model of spared nerve injury (SNI) of the sciatic nerve, we assess bio-molecular modifications in glutamatergic synapses in the mPFC that underlie neuropathic pain-induced plastic changes at 30 days post-surgery. Moreover, we examine the effects of palmitoylethanolamide (PEA) administration on pain-related behaviours, as well as the cortical biochemical and morphological changes that occur in SNI animals.

RESULTS

At 1 month, SNI was associated with mechanical and thermal hypersensitivity, as well as depression-like behaviour, cognitive impairments, and obsessive-compulsive activities. Moreover, we observed an overall glutamate synapse modification in the mPFC, characterized by changes in synaptic density proteins and amino acid levels. Finally, with regard to the resolution of pain and depressive-like syndrome in SNI mice, PEA restored the glutamatergic synapse proteins and changes in amino acid release.

CONCLUSIONS

Given the potential role of the mPFC in pain mechanisms, our findings may provide novel insights into neuropathic pain forebrain processes and indicate PEA as a new pharmacological tool to treat neuropathic pain and the related negative affective states. Graphical Abstract Palmitoylethanolamide: a new pharmacological tool to treat neuropathic pain and the related negative affective states.

The genetic ablation or pharmacological inhibition of TRPV1 signalling is beneficial for the restoration of quiescent osteoclast activity in ovariectomized mice

BACKGROUND AND PURPOSE

Osteoporosis is a condition characterized by a decrease in bone density, which decreases its strength and results in fragile bones. The endocannabinoid/endovanilloid system has been shown to be involved in the regulation of skeletal remodelling. The aim of this study was to investigate the possible modulation of bone mass mediated by the transient receptor potential vanilloid type 1 channel (TRPV1) in vivo and in vitro.

EXPERIMENTAL APPROACH

A multidisciplinary approach, including biomolecular, biochemical and morphological analysis, was used to investigate the involvement of TRPV1 in changes in bone density in vivo and osteoclast activity in vitro, in wild-type and Trpv1(-/-) mice, that had undergone ovariectomy or had a sham operation.

KEY RESULTS

Genetic deletion of Trpv1 as well as pharmacological inhibition/desensitization of TRPV1 signalling dramatically reduced the osteoclast activity in vitro and prevented the ovariectomy-induced bone loss in vivo, whereas the expression of cannabinoid type 2 (CB2 ) receptors was increased.

CONCLUSIONS AND IMPLICATIONS

These findings highlight the pivotal role TRPV1 channels play in bone resorption and suggest a possible cross-talk between TRPV1 and CB2 receptors. Based on these results, hybrid compounds acting on both TRPV1 and CB2 receptors in an opposite manner could provide a future pharmacological tool for the treatment of diseases associated with disturbances in the bone remodelling process.

The A1 adenosine receptor as a new player in microglia physiology

The purinergic system is highly involved in the regulation of microglial physiological processes. In addition to the accepted roles for the P2 X4,7 and P2 Y12 receptors activated by adenosine triphosphate (ATP) and adenosine diphosphate, respectively, recent evidence suggests a role for the adenosine A2A receptor in microglial cytoskeletal rearrangements. However, the expression and function of adenosine A1 receptor (A1AR) in microglia is still unclear. Several reports have demonstrated possible expression of A1AR in microglia, but a new study has refuted such evidence. In this study, we investigated the presence and function of A1AR in microglia using biomolecular techniques, live microscopy, live calcium imaging, and in vivo electrophysiological approaches. The aim of this study was to clarify the expression of A1AR in microglia and to highlight its possible roles. We found that microglia express A1AR and that it is highly upregulated upon ATP treatment. Moreover, we observed that selective stimulation of A1AR inhibits the morphological activation of microglia, possibly by suppressing the Ca(2+) influx induced by ATP treatment. Finally, we recorded the spontaneous and evoked activity of spinal nociceptive-specific neuron before and after application of resting or ATP-treated microglia, with or without preincubation with a selective A1AR agonist. We found that the microglial cells, pretreated with the A1AR agonist, exhibit lower capability to facilitate the nociceptive neurons, as compared with the cells treated with ATP alone.

Heavy smoking and lung cancer: are women at higher risk? Result of the ICARE study

Background:

Whether women are more or equally susceptible to the carcinogenic effects of cigarette smoke on the lungs compared with men is a matter of controversy. Using a large French population-based case–control study, we compared the lung cancer risk associated with cigarette smoking by gender.

Methods:

The study included 2276 male and 650 female cases and 2780 male and 775 female controls. Lifetime smoking exposure was represented by the comprehensive smoking index (CSI), which combines the duration, intensity and time since cessation of smoking habits. The analysis was conducted among the ever smokers. All of the models were adjusted for age, department (a regional administrative unit), education and occupational exposures.

Results:

Overall, we found that the lung cancer risk was similar among men and women. However, we found that women had a two-fold greater risk associated with a one-unit increase in CSI than men of developing either small cell carcinoma (OR=15.9, 95% confidence interval (95% CI) 7.6, 33.3 and 6.6, 95% CI 5.1, 8.5, respectively; P<0.05) or squamous cell carcinoma (OR=13.1, 95% CI 6.3, 27.3 and 6.1, 95% CI 5.0, 7.3, respectively; P<0.05). The association was similar between men and women for adenocarcinoma.

Conclusion:

Our findings suggest that heavy smoking might confer to women a higher risk of lung cancer as compared with men.

Selective antimicrobial activity and mode of action of adepantins, glycine-rich peptide antibiotics based on anuran antimicrobial peptide sequences

A challenge when designing membrane-active peptide antibiotics with therapeutic potential is how to ensure a useful antibacterial activity whilst avoiding unacceptable cytotoxicity for host cells. Understanding their mode of interaction with membranes and the reasons underlying their ability to distinguish between bacterial and eukaryotic cytoplasmic cells is crucial for any rational attempt to improve this selectivity. We have approached this problem by analysing natural helical antimicrobial peptides of anuran origin, using a structure-activity database to determine an antimicrobial selectivity index (SI) relating the minimal inhibitory concentration against Escherichia coli to the haemolytic activity (SI=HC(50)/MIC). A parameter that correlated strongly with SI, derived from the lengthwise asymmetry of the peptides' hydrophobicity (sequence moment), was then used in the "Designer" algorithm to propose novel, highly selective peptides. Amongst these are the 'adepantins', peptides rich in glycines and lysines that are highly selective for Gram-negative bacteria, have an exceptionally low haemolytic activity, and are less than 50% homologous to any other natural or synthetic antimicrobial peptide. In particular, they showed a very high SI for E. coli (up to 400) whilst maintaining an antimicrobial activity in the 0.5-4μM range. Experiments with monomeric, dimeric and fluorescently labelled versions of the adepantins, using different bacterial strains, host cells and model membrane systems provided insight into their mechanism of action.

Pharmacological activity of a Bv8 analogue modified in position 24

BACKGROUND AND PURPOSE

The amphibian peptide Bv8 induces potent nociceptive sensitization in rodents. Its mammalian homologue, prokineticin 2 (PROK2), is strongly up-regulated in inflamed tissues and is a major determinant in triggering inflammatory pain. Bv8 and PROK2 activate two closely related GPCRs, PK(1) and PK(2) , in a relatively non-selective fashion. To characterize better the roles of the two receptors in hyperalgesia and to obtain ligands whose binding affinity and efficacy differed for the two receptors, we modified the Bv8 molecule in regions essential for receptor recognition and activation.

EXPERIMENTAL APPROACH

We modified the Bv8 molecule by substituting Trp in position 24 with Ala (A-24) and compared it with Bv8 for binding and activating PK(1) and PK(2) receptors in cell preparations and in affecting nociceptive thresholds in rodents.

KEY RESULTS

A-24 preferentially bound to PK(2) receptors and activated them with a lower potency (5-fold) than Bv8. When systemically injected, A-24 induced Bv8-like hyperalgesia in rats and in mice, at doses 100 times higher than Bv8. Locally and systemically injected at inactive doses, A-24 antagonized Bv8-induced hyperalgesia. In rat and mouse models of inflammatory and post-surgical pain, A-24 showed potent and long-lasting anti-hyperalgesic activity. Unlike Bv8, A-24 increased β-endorphin levels in mouse brain.

CONCLUSIONS AND IMPLICATIONS

A-24 induced its anti-hyperalgesic effect in rodents by directly blocking nociceptor PK(1) receptors and by activating the central opioid system and the descending pain control pathway through brain PK(2) receptors.

Identification of antimicrobial peptides from teleosts and anurans in expressed sequence tag databases using conserved signal sequences

The problem of multidrug resistance requires the efficient and accurate identification of new classes of antimicrobial agents. Endogenous antimicrobial peptides produced by most organisms are a promising source of such molecules. We have exploited the high conservation of signal sequences in teleost and anuran antimicrobial peptides to search cDNA (expressed sequence tag) databases for likely candidates. Subject sequences were then analysed for the presence of potential antimicrobial peptides based on physicochemical properties (amphipathic helical structure, cationicity) and use of the D-descriptor model to predict the therapeutic index (relation between the minimum inhibitory concentration and the concentration giving 50% haemolysis). This analysis also suggested mutations to probe the role of the primary structure in determining potency and selectivity. Selected sequences were chemically synthesized and the antimicrobial activity of the peptides was confirmed. In particular, a short (21-residue) sequence, likely of sticklefish origin, showed potent activity and it was possible to tune the spectrum of action and/or selectivity by combining three directed mutations. Membrane permeabilization studies on both bacterial and host cells indicate that the mode of action was prevalently membranolytic. This method opens up the possibility for more effective searching of the vast and continuously growing expressed sequence tag databases for novel antimicrobial peptides, which are likely abundant, and the efficient identification of the most promising candidates among them.

Comparative activity and mechanism of action of three types of bovine antimicrobial peptides against pathogenic Prototheca spp

The yeast-like algae of the genus Prototheca are ubiquitous saprophytes causing infections in immunocompromised patients and granulomatous mastitis in cattle. Few available therapies and the rapid spread of resistant strains worldwide support the need for novel drugs against protothecosis. Host defence antimicrobial peptides inactivate a wide array of pathogens and are a rich source of leads, with the advantage of being largely unaffected by microbial resistance mechanisms. Three structurally diverse bovine peptides [BMAP-28, Bac5 and lingual antimicrobial peptide (LAP)] have thus been tested for their capacity to inactivate Prototheca spp. In minimum inhibitory concentration (MIC) assays, they were all effective in the micromolar range against clinical mastitis isolates as well as a Prototheca wickerhamii reference strain. BMAP-28 sterilized Prototheca cultures within 30-60 min at its MIC, induced cell permeabilization with near 100% release of cellular adenosine triphosphate and resulted in extensive surface blebbing and release of intracellular material as observed by scanning electron microscopy. Bac5 and LAP inactivated Prototheca following 3-6 h incubation at fourfold their MIC and did not result in detectable surface damage despite 70-90% killing, suggesting they act via non-lytic mechanisms. In circular dichroism studies, the conformation of BMAP-28, but not that of Bac5 or LAP, was affected by interaction with liposomes mimicking algal membranes. Our results indicate that BMAP-28, Bac5 and LAP kill Prototheca with distinct potencies, killing kinetics, and modes of action and may be appropriate for protothecal mastitis treatment. In addition, the ability of Bac5 and LAP to act via non-lytic mechanisms may be exploited for the development of target-selective drugs.

Antibacterial and anti-biofilm effects of cathelicidin peptides against pathogens isolated from cystic fibrosis patients

Six different cathelicidin-derived peptides were compared to tobramycin for antibacterial and anti-biofilm effects against S. aureus, P. aeruginosa, and S. maltophilia strains isolated from cystic fibrosis patients. Overall, SMAP-29, BMAP-28, and BMAP-27 showed relevant antibacterial activity (MIC(50) 4-8μg/ml), and in some cases higher than tobramycin. In contrast, indolicidin, LL-37, and Bac7(1-35) showed no significant antimicrobial activity (MIC(50)>32μg/ml). Killing kinetics experiments showed that in contrast to tobramycin the active cathelicidin peptides exert a rapid bactericidal activity regardless of the species tested. All three peptides significantly reduced biofilm formation by S. maltophilia and P. aeruginosa strains at 1/2× MIC, although at a lower extent than tobramycin. In addition, BMAP-28, as well as tobramycin, was also active against S. aureus biofilm formation. Preformed biofilms were significantly affected by bactericidal SMAP-29, BMAP-27 and BMAP-28 concentrations, although at a lesser extent than tobramycin. Overall, our results indicate the potential of some cathelicidin-derived peptides for the development of novel therapeutic agents for cystic fibrosis lung disease.

[Gastric cancer: surgical treatment and prognostic score]

AIM

Gastric cancer is the fifth most common cause of tumor-related death in Western countries. Surgery is the only effective treatment but only 50-60% of patients can receive a curative treatment because of absent or aspecific symptoms. The aim of this study was to develop a scale for gastric cancer patients that takes into account factors related to the tumor and to the patient.

METHODS

Fifty-seven patients with gastric adenocarcinoma admitted to the Department of General, Geriatric Surgery and Diagnostic and Operative Endoscopy of the University ''Federico II'' in Naples, and treated by gastrectomy from January 1998 until December 2002, were included in this retrospective cohort. The prognostic score was created according to the variables identified in Cox analysis as statistically significant (P 0.1).

RESULTS

The 5-year mortality rate was 61%. Cox analysis identified these variables with a significant effect on mortality: age ?60 (odds ratio (OR) 4.16; P=0.015), smoking or alcoholism (OR 2.66; P=0.057), pTNM I (OR 0.04; P=0.003), pTNM II (OR 0.18; P=0.029), pTNM III (OR 0.27; P=0.023), pTNM IV (OR 3.28; P=0.012), lymph node ratio (LNR) <20% (OR 0.15; P=0.01), LNR 20% (OR 3.83; P=0.002), Lauren diffuse histotype (OR 2.41; P=0.1) and location of the neoplasm at superior third (OR 6.70; P=0.003), middle third (OR 5.60; P=0.003), or inferior third (OR 0.32; P=0.008). Patients have been randomized into three groups according to their scores (3-40.5; 41-78.5; 79-115.5) and the 5-year mortality rate was 46%, 59%, 90% in group 1, 2 and 3 respectively.

CONCLUSION

It is necessary to consider in prognostic stratification of gastric cancer patients not only pTNM staging but also other factors such as age, smoking or alcoholism, Lauren histotype, location and linfonodal involvement. It is possible to design a more effective prognostic score predicting the individual risk and addressing the therapy and the follow-up.

[Surgical treatment and prognostic factors in colorectal cancer]

AIM

The aim of this study was to make a contribution to improve the care of patients with colorectal cancer by optimizing times and methods of the follow-up; particular attention is given to factors which may be important for the prognosis and for the quality of life in the immediate postoperative period.

METHODS

The study includes all the patients with colorectal cancer who underwent laparotomic surgical treatment from 1996 to 2003. The total number of patients was 226 with an average age of 65 years; male to female ratio was 1.57:1. According to the stage of tumor, an adjuvant radiotherapeutic and/or chemiotherapeutic treatment was associated to surgery.

RESULTS

On the basis of the preoperative staging and tumor localization, our patients underwent: 3 total colectomies, 57 right hemicolectomies, 137 left hemicolectomies, 6 Hartmann resections, 19 Miles resections, 4 transverse resections.

CONCLUSION

The results obtained show that the 5-year overall survival is particularly influenced by the stage and the factors which directly or indirectly affect the primary tumor; thus the prognostic factors which should be considered for the survival and in the follow-up of these patients are: stage, grading and nodal involvement of the tumor.

Cranial aneurysmal bone cyst: a diagnostic problem. With a review of the literature

Aneurysmal bone cysts (ABC) are benign osteolytic lesions that are more common in young people than in adults and involve the skull only exceptionally. The origin of ABC is still debated; indeed, some authors consider ABC to be an anomalous bony reaction that is secondary to traumas or tumours. Conversely, others consider ABC to be a distinct entity. A case of a healthy young female affected by a left frontal ABC is reported here. The clinical onset was characterised by the sudden appearance of a tender and mildly painful frontal mass. Neuroradiological assessment showed a well-circumscribed lytic lesion of the frontal bone with predominantly outward extension. En bloc surgical removal of the lesion was successfully achieved; a reconstructive cranioplasty was also performed to repair the cranial defect. The rarity of the condition described, together with the absence of clear guidelines, prompted us to review the more recent literature with the twin goals of identifying radiological features and becoming able to address the diagnosis and rules for treatment of such a rare entity.

Ependymoma of the fourth ventricle presenting with hemifacial spasm. Report of a case

According to Gardner's hypothesis (1962) later confirmed by Jannetta (1982, 1985), hemifacial spasm can usually be related to a "vascular conflict" which takes place inside the cerebellopontine angle (CPA). Occasionally, the causative lesion can be identified as a mass encasing the facial nerve at its root exit zone (REZ) from the brain stem. The hemifacial spasm has been rarely reported in presence of a contralateral CPA mass ("false localising sign"). Hemifacial spasm in patients with masses in anatomical regions other than the CPA has to be considered exceptional. The case of an adult man harboring an ependymoma of the fourth ventricle whose only neurological sign was a left hemifacial spasm is reported. The rarity of such a condition prompted us to review the literature. Particular attention has been paid to the possible pathogenetic mechanisms and their therapeutic implications.