Bacterial Cellulose Hybrid Composites with Calcium Phosphate for Bone Tissue Regeneration.

Bacterial cellulose (BC) is a unique microbial biopolymer with a huge number of significant applications in the biomedical field, including bone tissue engineering. The present study proposes to obtain and characterize BC hybrid composites with calcium phosphate as biocompatible and bioactive membranes for bone tissue engineering. BC precursor membranes were obtained in static culture fermentation, and after purification, were oxidized to obtain 2,3-dialdehyde bacterial cellulose (DABC). Calcium phosphate-BC oxidized membranes were produced by successive immersion in precursor solutions under ultrasonic irradiation. The samples were characterized for their physicochemical properties using scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectroscopy, attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy grazing incidence X-ray diffraction (GI-XRD), solid-state 13C nuclear magnetic resonance (CP/MAS 13C NMR), and complex thermal analysis. In vitro cell studies were also performed to evaluate the influence of modified morphological characteristics on cell adhesion and proliferation. The results showed an increase in porosity and biodegradability for DABC hybrid composites compared with BC. In vitro cell studies have revealed that both hybrid composites favor cell adhesion to the surface. The new BC and DABC hybrid composites with calcium phosphate could be considered promising materials for bone tissue regeneration.

Magnetic Separation and Centri-Chronoamperometric Detection of Foodborne Bacteria Using Antibiotic-Coated Metallic Nanoparticles.

Quality and food safety represent a major stake and growing societal challenge in the world. Bacterial contamination of food and water resources is an element that pushes scientists to develop new means for the rapid and efficient detection and identification of these pathogens. Conventional detection tools are often bulky, laborious, expensive to buy, and, above all, require an analysis time of a few hours to several days. The interest in developing new, simple, rapid, and nonlaborious bacteriological diagnostic methods is therefore increasingly important for scientists, industry, and regulatory bodies. In this study, antibiotic-functionalized metallic nanoparticles were used to isolate and identify the foodborne bacterial strains Bacillus cereus and Shigella flexneri. With this aim, a new diagnostic tool for the rapid detection of foodborne pathogenic bacteria, gold nanoparticle-based centri-chronoamperometry, has been developed. Vancomycin was first stabilized at the surface of gold nanoparticles and then incubated with the bacteria B. cereus or S. flexneri to form the AuNP@vancomycin/bacteria complex. This complex was separated by centrifugation, then treated with hydrochloric acid and placed at the surface of a carbon microelectrode. The gold nanoparticles of the formed complex catalyzed the hydrogen reduction reaction, and the generated current was used as an analytical signal. Our results show the possibility of the simple and rapid detection of the S. flexneri and B. cereus strains at very low numbers of 3 cells/mL and 12 cells/mL, respectively. On the other hand, vancomycin-capped magnetic beads were easily synthesized and then used to separate the bacteria from the culture medium. The results show that vancomycin at the surface of these metallic nanoparticles is able to interact with the bacteria membrane and then used to separate the bacteria and to purify an inoculated medium.

Evaluation of the Ability of Nanostructured PEI-Coated Iron Oxide Nanoparticles to Incorporate Cisplatin during Synthesis.

Nanoparticles (NPs) have a high potential for biological applications as they can be used as carriers for the controlled release of bioactive factors. Here we focused on poly(ethylenimine) (PEI)-coated iron oxide hybrid NPs obtained by hydrothermal synthesis in high pressure conditions and evaluated their behavior in culture medium in the presence or absence of cells, as well as their ability to incorporate antitumor drug cisplatin. Our results showed that the hydrothermal conditions used for Fe-PEI NPs synthesis allowed the incorporation of cisplatin, which even increased its anti-tumor effects. Furthermore, the commonly occurring phenomenon of NPs aggregation in culture medium was exploited for further entrapment of other active molecules, such as the fluorescent dye DiI and valinomycin. The molecules bound to NPs during synthesis or during aggregation process were delivered inside various cells after in vitro and in vivo direct contact between cells and NPs and their biological activity was preserved, thus supporting the therapeutic value of Fe-PEI NPs as drug delivery tools.

Repair of the Orbital Wall Fractures in Rabbit Animal Model Using Nanostructured Hydroxyapatite-Based Implant.

Cellular uptake and cytotoxicity of nanostructured hydroxyapatite (nanoHAp) are dependent on its physical parameters. Therefore, an understanding of both surface chemistry and morphology of nanoHAp is needed in order to be able to anticipate its in vivo behavior. The aim of this paper is to characterize an engineered nanoHAp in terms of physico-chemical properties, biocompatibility, and its capability to reconstitute the orbital wall fractures in rabbits. NanoHAp was synthesized using a high pressure hydrothermal method and characterized by physico-chemical, structural, morphological, and optical techniques. X-ray diffraction revealed HAp crystallites of 21 nm, while Scanning Electron Microscopy (SEM) images showed spherical shapes of HAp powder. Mean particle size of HAp measured by DLS technique was 146.3 nm. Biocompatibility was estimated by the effect of HAp powder on the adhesion and proliferation of mesenchymal stem cells (MSC) in culture. The results showed that cell proliferation on powder-coated slides was between 73.4% and 98.3% of control cells (cells grown in normal culture conditions). Computed tomography analysis of the preformed nanoHAp implanted in orbital wall fractures, performed at one and two months postoperative, demonstrated the integration of the implants in the bones. In conclusion, our engineered nanoHAp is stable, biocompatible, and may be safely considered for reconstruction of orbital wall fractures.

Dendritic cells and hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) represents a major health burden in the modern world. Because current treatment options for HCC are capable of providing good survival rates to only a limited number of patients, new therapeutic opportunities should be looked upon. The particularities of dendritic cells (DC) populations existing in the liver, and their consecutive selective activation of certain immunotolerant T-cell subgroups, account for the high success rate of allogeneic hepatic transplantation, currently the most efficient treatment for HCC. The particularities of dendritic cells (DCs) populations existing in the liver, and their consecutive selective activation of certain immunotolerant T-cell subgroups, account for the high success rate of allogeneic hepatic transplantation for HCC. These molecular mechanisms also open new paths towards cancer preventing and cancer curative vaccines, as well as successful immunotherapy. Our aim was to summarize the main aspects of the biology of DCs populations, especially those present in the liver, and to draw attention to their current and future roles in the curative treatment of hepatocarcinoma.

Effect of diet and omega-3 fatty acids in NAFLD.

Nonalcoholic fatty liver disease (NAFLD) ranges from simple hepatic steatosis to steatohepatitis (NASH) and cirrhosis. The aim of this study is to test beneficial effects of omega-3 fatty acids (DHA 130 mg, EPA 25 mg) treatment in NAFLD, in a mouse model of non-alcoholic fatty liver disease. As pretreatment, 50 mice were fed for one month with a high-fat diet to induce NAFLD. Then, the mice were divided in different groups according to diet (normo- or hypercaloric), with and without treatment with omega-3 fatty acids, for another month, forming the post-treatment group. The liver and blood samples were collected for biochemical and histopathological analysis. Biochemical parameters including: glycemia, total cholesterol, triglycerides, uric acid, albumin, total plasma antioxidant capacity (TEAC) was measured in serum. Glutathione (GSH), total thiols and malonyldialdehyde (MDA) were determined in mouse liver homogenates. Mice from post-treatment group, on hypercaloric diet with or without omega-3 fatty acids treatment, had medium hepatopathy (granular and vacuolar degeneration of the hepatocytes) and hypertriglyceridemia. Omega-3 fatty acid treatment lowered the rise of triglycerides (p<0.03), glycemia (p<0.01) and cholesterol (p<0.02) in serum and MDA level of the liver (p<0.05). Mice from post-treatment group, on normocaloric diet with or without omega-3 fatty acid had different histopathological and biochemical results. Those with normocaloric/normolipidic diet and omega-3 fatty acids treatment had reversed liver histopathological results from NASH to normal aspect and had the best metabolic parameters results. In conclusion, omega-3 fatty acids treatment associated with a normocaloric/normolipidic diet has hepatoprotective action in nonalcoholic fatty liver disease.

Interference of alpha-alkyl-substituted pirinixic acid derivatives with neutrophil functions and signalling pathways.

Pirinixic acid (Wy-14,643) is an agonist of the peroxisome proliferator-activated receptor (PPAR) subtype alpha exhibiting beneficial effects in various inflammation-related processes in a slow, long-termed fashion. We recently showed that alpha-substituted pirinixic acid derivatives are agonists of PPAR alpha and act as dual inhibitors of 5-lipoxygenase (5-LO, EC 1.13.11.34) and the microsomal prostaglandin E(2) synthase-1 (EC 5.3.99.3). Here, we explored short-term effects of alpha-substituted pirinixic acid derivatives on typical neutrophil functions evoked by the agonist N-formyl-methionyl-leucyl-phenylalanine (fMLP) including leukotriene formation, generation of reactive oxygen species, and release of human leukocyte elastase (EC 3.4.21.37), and we investigated the modulation of related signalling pathways. Pirinixic acid derivatives that are substituted with alkyl residues in alpha-position of the carboxylic group and with a 6-aminoquinoline residue at the pyrimidine moiety cause inhibition of leukotriene formation, reactive oxygen species formation, and leukocyte elastase release in response to fMLP. In parallel, Ca(2+) mobilisation and the phosphorylation (activation) of p38 mitogen-activated protein kinase was significantly reduced, whereas phosphorylation of the extracellular signal-regulated kinase-2 was unaffected. Pirinixic acid itself was not or only marginally active in all these assays. Conclusively, targeted structural modification of pirinixic acid leads to bioactive compounds that display immediate anti-inflammatory properties in human neutrophils with potential therapeutic value.

Systemic redox modifications in senile cataract.

UNLABELLED: Recent studies on cataract formation focus on a primary role of systemic oxidative stress, generated outside the lens. Plasma inflammatory markers are associated with senile cataract. OBJECTIVE: The aim of this study was to find correlations between blood oxidative stress markers and some inflammatory plasma markers in cataractous patients. DESIGN AND METHODS: The blood samples were collected from 38 patients (aged 50 to 80). Patients were subdivided according to two criteria. Considering age criteria, presenile and senile cataract groups were formed. According to the absence or presence of other ocular comorbidities (age-related macular degeneration, glaucoma), pure cataract and nonpure cataract groups were constituted. Fifteen age and sex matched healthy subjects were selected for the control group. RESULTS: In our study, for all groups of patients, the measured markers of oxidative stress were modified vs. control values. Plasma antioxidant capacity, plasma antioxidant "gap", cholesterol and albumin/globulin levels were significantly decreased while RBC SOD activity, RBC catalase activity and plasma ceruloplasmin were significantly increased. Inflammatory markers, ceruloplasmin and albumin/globulins were correlated with different parameters of oxidative stress. CONCLUSION: The blood redox values and the level of some inflammatory markers demonstrate that senile cataract is a systemic disease with an inflammatory component.

Novel and potent inhibitors of 5-lipoxygenase product synthesis based on the structure of pirinixic acid.

A novel class of potent 5-lipoxygenase (5-LO) product synthesis inhibitors based on the structure of pirinixic acid (4-chloro-6-(2,3-xylidino)-2-pyrimidinylthioacetic acid, compound 1) is presented. Systematic profiling of 1, i.e., esterification of the carboxylic acid, alpha-substitution, and replacement of the o-dimethylaniline by 6-aminoquinoline, leads to potent suppressors of 5-LO product formation in activated polymorphonuclear leukocytes, exemplified by ethyl 2-[4-chloro-6-(quinoline-6-ylamino)-pyrimidin-2-ylsulfanyl]octane-1-carboxylate (6d, IC50 = 0.6 microM). These derivatives may possess potential for intervention with inflammatory and allergic diseases.

The treatment of dyslipidemia--what's left in the pipeline?

Dyslipidemia is a pathological alteration of serum lipid levels. The most common forms are either elevations of triglycerides or low density lipoprotein cholesterol associated with a reduction of high density lipoprotein cholesterol. Most frequently both forms of lipid disorders are combined. Elevations of free fatty acid blood levels are commonly not subsumed under the term dyslipidemia. However, free fatty acids should also be considered, as they are frequently associated with dyslipidemia and represent a risk factor for cardiovascular diseases. Dyslipidemias are among the major etiologic factors for arterial occlusive diseases. Resulting in fatal implications such as stroke and coronary heart disease, dyslipidemias contribute to the most prevalent causes of death. Lowering of low density lipoprotein and raising of high density lipoprotein cholesterol levels have been shown in both epidemiologic and intervention studies to decrease mortality. Established treatments of dyslipidemias are statins and fibrates. However, recent research has established some new potential therapeutic targets which are currently investigated in clinical trials. New therapeutic approaches include subtype selective, dual, and pan-agonists of the peroxisome proliferator activated receptor, inhibitors of the cholesterol ester transfer protein, Acyl-CoA-cholesterol-acyltransferase, squalene synthase, microsomal triglycerid-transfer-protein, and cholesterol absorption. Clinical implications of new drugs under investigation are discussed in this review.

Quinoline-based derivatives of pirinixic acid as dual PPAR alpha/gamma agonists.

Pirinixic acid is known for its peroxisome proliferator-activated receptor (PPAR) agonistic action. In a recent publication, we have shown that aliphatic alpha-substitution of pirinixic acid enhances both PPARalpha and PPARgamma agonism. The goal of this study was to evaluate, whether the PPAR agonism of pirinixic acid may be also maintained in quinoline-based derivatives. The present study revealed that the mere substitution of the dimethyl aniline moiety of pirinixic acid by quinoline leads to a total loss of PPARalpha/gamma agonism, whereas concomitant alpha-substitution with n-butyl or n-hexyl groups restores and even enforces PPAR activation, leading to potent dual PPARalpha/gamma agonists. In the following we report the synthesis of quinoline-based derivatives of pirinixic acid, which in a Gal4-based luciferase-reporter gene assay proved to be potent dual PPARalpha/gamma agonists. Molecular docking of compound 4 with FlexX suggests a binding mode resembling to that of tesaglitazar.

[Risk factors in cataract]. / Factorii de risc in cataracta.

Cataract is one of the major causes of blindness throughout the world. Considerable effort to elucidate risk factors for cataract has been undertaken in hopes that simple, preventive strategies may be implemented to avoid or delay the progression of lens opacification. Advanced age, female gender, poor education, lower socioeconomic status, high or low body mass index and heavy alcohol consumption are some risk factors for senile cataract. Smoking appears to provide an oxidative challenge associated with depletion of antioxidants as well as with enhanced risk for cataract formation. Multiple drugs are responsive in iatrogenic cataract. Nonsteroidal anti-inflammatory drugs (NSAIDs) and pyruvate may have protective effects for senile cataract. Randomized clinical trials should be encouraged to find medical therapeutic ways to delay the cataract development.

[Blood constituents and senile cataract]. / Diversi compusi plasmatici si cataracta senila.

In cataractous older age group subjects, different blood constituents have the mean concentrations and standard deviations within normal limits but, of course, differing significantly from the corresponding means in the control population. Various morphological types of senile cataract have different risk factors. The mechanisms underlying the associations between different blood constituents with different patterns of lens opacification remain to be elucidated.