Giovanni Li Destri

BENEFICIAL EFFECTS OF RUTIN AND L-ARGININE COADMINISTRATION IN A RAT MODEL OF LIVER ISCHEMIA/REPERFUSION INJURY

Reperfusion following liver ischemia results in oxidative stress leading to liver injury. The aim of this study was to investigate the combined effects of two antioxidant agents, rutin and L-arginine, in rat liver ischemia-reperfusion (I/R). Male Wistar rats were divided into five groups: 1) sham operated, 2) I/R, 3) I/R+rutin, 4) I/R+L-arginine, and 5) I/R+rutin+L-arginine. Plasmatic and hepatic levels of alanine transaminase (ALT), aspartate transaminase (AST), lipid peroxides (LOOH), and thiol groups (RSH) were examined, as well as DNA fragmentation and liver histopathology. Furthermore, to elucidate the pathophysiological processes involved in the antioxidant mechanism(s) of rutin and L-arginine, we assessed the expression of inducible (iNOS) and endothelial nitric oxide synthase (eNOS) isoforms and heme oxygenase-1 (HO-1), both playing key roles in the biochemical cascade of liver injury. Significant increase in plasmatic ALT and AST activities were observed in untreated I/R rats compared with sham-operated animals, whereas treatment with rutin or L-arginine in I/R rats reduced hepatic damage. Interestingly, combined therapy with rutin and L-arginine resulted in a further reduction of plasmatic ALT and AST activities compared with rutin or L-arginine alone. These results were further confirmed by the analysis of DNA fragmentation, LOOH, RSH groups, and liver histopathology, which showed the highest protective effects following the coadministration of rutin and L-arginine. Finally, the combined therapy protocol resulted in a significant induction of liver HO-1 and a concomitant reduction of iNOS expression that may both be responsible for the beneficial effects of the proposed pharmacological protocol.

Mixed zirconia calcium phosphate coatings for dental implants: tailoring coating stability and bioactivity potential.

Enhanced coating stability and adhesion are essential for long-term success of orthopedic and dental implants. In this study, the effect of coating composition on mechanical, physico-chemical and biological properties of coated zirconia specimens is investigated. Zirconia discs and dental screw implants are coated using the wet powder spraying (WPS) technique. The coatings are obtained by mixing yttria-stabilized zirconia (TZ) and hydroxyapatite (HA) in various ratios while a pure HA coating served as reference material. Scanning electron microscopy (SEM) and optical profilometer analysis confirm a similar coating morphology and roughness for all studied coatings, whereas the coating stability can be tailored with composition and is probed by insertion and dissections experiments in bovine bone with coated zirconia screw implants. An increasing content of calcium phosphate (CP) resulted in a decrease of mechanical and chemical stability, while the bioactivity increased in simulated body fluid (SBF). In vitro experiments with human osteoblast cells (HOB) revealed that the cells grew well on all samples but are affected by dissolution behavior of the studied coatings. This work demonstrates the overall good mechanical strength, the excellent interfacial bonding and the bioactivity potential of coatings with higher TZ contents, which provide a highly interesting coating for dental implants.

The apoptotic machinery as a biological complex system: analysis of its omics and evolution, identification of candidate genes for fourteen major types of cancer, and experimental validation in CML and neuroblastoma

BackgroundApoptosis is a critical biological phenomenon, executed under the guidance of the Apoptotic Machinery (AM), which allows the physiologic elimination of terminally differentiated, senescent or diseased cells. Because of its relevance to BioMedicine, we have sought to obtain a detailed characterization of AM Omics in Homo sapiens, namely its Genomics and Evolution, Transcriptomics, Proteomics, Interactomics, Oncogenomics, and Pharmacogenomics.MethodsThis project exploited the methodology commonly used in Computational Biology (i.e., mining of many omics databases of the web) as well as the High Throughput biomolecular analytical techniques.ResultsIn Homo sapiens AM is comprised of 342 protein-encoding genes (possessing either anti- or pro-apoptotic activity, or a regulatory function) and 110 MIR-encoding genes targeting them: some have a critical role within the system (core AM nodes), others perform tissue-, pathway-, or disease-specific functions (peripheral AM nodes). By overlapping the cancer type-specific AM mutation map in the fourteen most frequent cancers in western societies (breast, colon, kidney, leukaemia, liver, lung, neuroblastoma, ovary, pancreas, prostate, skin, stomach, thyroid, and uterus) to their transcriptome, proteome and interactome in the same tumour type, we have identified the most prominent AM molecular alterations within each class. The comparison of the fourteen mutated AM networks (both protein- as MIR-based) has allowed us to pinpoint the hubs with a general and critical role in tumour development and, conversely, in cell physiology: in particular, we found that some of these had already been used as targets for pharmacological anticancer therapy. For a better understanding of the relationship between AM molecular alterations and pharmacological induction of apoptosis in cancer, we examined the expression of AM genes in K562 and SH-SY5Y after anticancer treatment.ConclusionWe believe that our data on the Apoptotic Machinery will lead to the identification of new cancer genes and to the discovery of new biomarkers, which could then be used to profile cancers for diagnostic purposes and to pinpoint new targets for pharmacological therapy. This approach could pave the way for future studies and applications in molecular and clinical Medicine with important perspectives both for Oncology as for Regenerative Medicine.

Characterization of Wet Powder-Sprayed Zirconia/Calcium Phosphate Coating for Dental Implants

PURPOSE Yttria-stabilized zirconia (TZ) is used for dental applications because of its low toxicity and beneficial mechanical properties, but it does not stimulate bone regeneration around the implant due to its bioinertness. Therefore, hydroxyapatite (HA) coatings are often utilized to increase the surface bioactivity and to achieve a better osseointegration. These coatings, however, are chemically nonstable and provide a weak bonding to the substrate surface. MATERIALS AND METHODS In this study, zirconia substrates were coated with a calcium phosphate/zirconia mixture to achieve ceramic coatings with a high bioactivity potential and a good mechanical stability. The coatings were obtained by wet powder spraying (WPS). Pure HA and TZ coatings were employed as reference materials. The coatings were characterized with regard to microstructure, surface roughness, and phase composition. Scratch tests were carried out to investigate the coating adhesion. The influence of the coating on the mechanical strength was evaluated with the ball on three balls test (B3B). In addition, zirconia dental implant screws were also coated and inserted in a biomechanical test block and bovine rip bone. RESULTS After sintering, the mixed coating exhibited a porous morphology with a surface roughness of about 4 μm and a total porosity of 17%. Phase analysis showed a transformation from TZ and HA to calcium zirconium oxide and tricalcium phosphate. Investigations of the bond strength confirmed a strong adhesion of the mixed coating to the substrate, while the biaxial fracture strength was only slightly affected. Insertion experiments confirmed the scratch test results and evidenced an intact mixed coating on the zirconia screw. CONCLUSIONS The present study revealed a higher stability and firm adhesion of the mixed coating compared with a pure calcium phosphate coating. We also successfully demonstrate the particular versatility of the WPS technique for dental implants by coating a complex curved surface.

Interfacial Free Energy Driven Nanophase Separation in Poly(3-hexylthiophene)/[6,6]-Phenyl-C61-butyric Acid Methyl Ester Thin Films

The nanostructure of thermally annealed thin films of poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) blends on hydrophobic and hydrophilic substrates was studied to unravel the relationship between the substrate properties and the phase structure of polymer blends in confined geometry. Indeed, the nature of the employed substrates was found to affect the extent of phase separation, the PCBM aggregation state and the texture of the whole system. In particular, annealing below the melting temperature of the polymer yielded the formation of PCBM nanometric crystallites on the hydrophobic substrates, while mostly amorphous microscopic aggregates were formed on the hydrophilic ones. Moreover, while an enhanced in-plane orientation of P3HT lamellae was promoted on hydrophobic substrates, a markedly tilted geometry was produced on the hydrophilic ones. The observed effects were interpreted in terms of a simple model connecting the interface free energy for the blend films to the different polymer chain mobility and diffusion velocity of PCBM molecules on the different substrates.

Bile duct injury during laparoscopic cholecystectomy without intraoperative cholangiography: a retrospective study on 1,100 selected patients.

Background: Whether to routinely or selectively use intraoperative cholangiography (IOC) during laparoscopic cholecystectomy (LC) has been a controversial issue for many years. Many authors maintain that IOC decreases the rate of biliary complications such as bile duct injuries, biliary leak, and missed common bile duct (CBD) stones. However, in contrast to these claims, many centers have opted to perform LC without IOC. In this retrospective study, the results of a series of 1,100 LCs, all of which involved major biliary complications and which were performed without the use of IOC, were reviewed. Methods: Data from 1,100 selected patients (728 females and 372 males) undergoing LC without the use of IOC from January 2003 to November 2011 were analyzed. One hundred and seventy LCs were performed by young surgeons during the learning curve, and 930 by surgeons with over 10 years of experience. Two techniques were used to create pneumoperitoneum: the Veress technique in 319 cases (29%) and the Hasson technique in the remaining 781 cases (71%). Patients with a suspicion of CBD stones were excluded from the study. Results: Two CBD injuries (0.18%) and three biliary leaks (0.27%) were detected among this group. Thirty-three patients (3%) needed conversion to open cholecystectomy. Missed CBD stones were reported in 4 cases (0.36%). There was no postoperative mortality. Conclusion: LC can be performed safely without the use of IOC and with acceptable low rates of biliary complications. An accurate preoperative evaluation of clinical risk factors, precise operative procedures, and conversion to an open approach in doubtful cases are important measures which must be taken to prevent CBD injury.

Monitoring carcinoembryonic antigen in colorectal cancer: Is it still useful?

The results of a study conducted to determine the usefulness of carcinoembryonic antigen (CEA) monitoring in the follow-up of patients with resected colorectal cancer are reported herein. The subjects of this study were 125 patients in whom CEA had been determined preoperatively and 239 patients in whom CEA had been monitored postoperatively. The results revealed increased preoperative CEA in only 24% of the subjects, and that this increment was correlated with subsequent more advanced tumor stage and a higher recurrence rate (P<0.01). The postoperative CEA level exceeded the threshold in 71% of the patients affected by recurrence, 94.4% of whom developed liver metastases and 50%, nonhepatic recurrence. This marker showed elevated sensitivity for liver metastases (99%), whereas the sensitivity was lower for nonhepatic recurrence of the disease (94%). Thus, we concluded that CEA monitoring can be useful for preoperative colorectal tumor grading, even if its validity in the early diagnosis of recurrence is problematic, especially in terms of radical repeated surgery and survival.

Enhanced crystallinity and film retention of P3HT thin-films for efficient organic solar cells by use of preformed nanofibers in solution

We report the preparation of films of poly(3-hexylthiophene) nanofibers suitable for fabrication of efficient multilayer solar cells by successive deposition of donor and acceptor layers from the same solvent. The nanofibers are obtained by addition of di-tert-butyl peroxide (DTBP) to a solution of P3HT in chlorobenzene. Interestingly, by varying the concentration of DTBP we are able to control both crystallinity and film retention of the spin-cast films. We also investigate the influence of the DTBP-induced crystallization on charge transport by thin-film transistor measurements, and find a more than five-fold increase in the hole mobility of nanofiber films compared to pure P3HT. We attribute this effect to the synergistic effects of increased crystallinity of the fibers and the formation of micrometer-sized fiber networks. We further demonstrate how it is possible to make use of the high film retention to fabricate photovoltaic devices by subsequent deposition of [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) from a chlorobenzene solution on top of the nanofiber film. The presence of a relatively large crystalline phase strongly affects the diffusion behavior of PCBM into the P3HT film, resulting in a morphology which is different from that of common bulk heterojunction solar cells and resembles a bilayer structure, as can be inferred from comparison of the external quantum efficiency spectra. However, a high power conversion efficiency of 2.3% suggests that there is still a significant intermixing of the two materials taking place.

Crystal Morphologies and Polymorphs in Tolbutamide Microcrystalline Powder

The growing interest of pharmaceutical companies toward the crystal morphology prediction of active pharmaceutical ingredients is a consequence of the dramatic effect of the crystal habit on the tableting behavior of drugs. In order to help the optimization of the industrial process, molecular mechanics calculations together with X-ray diffraction analysis and optical microscopy (OM) were used to shed light over the structural properties of N-(butylcarbamoyl)-4-methylbenzenesulfonamide-commercially known as tolbutamide-a drug used in the management of type II diabetes, especially in elderly diabetics because of its rapid metabolism. As there are several known polymorphs of this molecule, we first defined, by means of a quantitative phase analysis, performed by X-ray powder diffraction, which and how much each of the five crystallographic structures present in the Cambridge Crystallographic Database represent the commercial crystalline powder. The structures of the resulting candidates were first analyzed by means of molecular mechanics, and the crystal morphologies of the compounds were therefore predicted and compared with the ones observed by means of OM. Analogies and differences among the different morphologies, together with the potential role of crystallization solvents, were commented in the attempt to bridge the gap between the molecular structure-that is, the atomic point of view-and the crystal habit.

Experimental models in microsurgery

The development of experimental microsurgery can be considered the natural evolution of a diffuse need to increase precision in many fields of surgery. Microsurgery accelerated the possibility of deepening many unclear aspects of pathophysiology, using miniaturized and reproducible experimental models. We report briefly on the fundamental principles of microsurgery and the most frequently performed and useful models of experimental microsurgery, especially to employ as training models for surgeons, but also as bases for developing new and always‐welcome models.