Preventive Activity of Olive Oil Phenolic Compounds on Alkene Epoxides Induced Oxidative DNA Damage on Human Peripheral Blood Mononuclear Cells

The aim of this study was to investigate the ability of epoxides of styrene (styrene-7,8-oxide; SO) and 1,3-butadiene (3,4-epoxy-1-butene; 1,2:3,4:-diepoxybutane) to cause oxidative stress and oxidative DNA damage on human peripheral blood mononuclear cells (PBMCs) and whether a complex mixture of olive oil phenols (OOPE) could prevent these effects. The DNA damage was measured by the single-cell gel electrophoresis (SCGE; comet assay). We found that the DNA damage induced by alkene epoxides could be prevented by N-acetyl-cysteine (10 mM) and catalase (100 U/ml). Alkene epoxides caused a significant (P < 0.05) increase of both peroxide concentration in extra- and intracellular environment and formamidopyrimidine DNA glycosylase (FPG)- and Endonuclease III (ENDO III)-sensitive sites in PBMCs, demonstrating the presence of oxidized bases. OOPE (1 μg of total phenols/ml) was able to prevent the alkene epoxide induced DNA damage both after 2 and 24 h of incubation. In addition, OOPE completely inhibited the SO-induced intracellular peroxide accumulation in PBMCs and prevented the oxidative DNA damage induced by SO, as evidenced by the disappearance of both FPG- and ENDO III-sensitive sites. This is the first study demonstrating the ability of OOPE to prevent the DNA damage induced by alkene epoxides providing additional information about the chemopreventive properties of olive oil.     

Prolonged Versus Short-Duration Use of Nasogastric Tubes in Patients with Head and Neck Cancer During Radiotherapy Alone or Combined Chemoradiotherapy

To compare safety and effectiveness of prolonged (>28 days) versus short duration (≤28 days) use of nasogastric tube for enteral nutrition and weight loss prevention during curative radiotherapy with or without concurrent chemotherapy or cetuximab for head and neck cancer patients. We performed a retrospective study and database review of all patients at our center, treated with radiotherapy for head and neck cancer receiving enteral nutrition by nasogastric tube. Type of treatment, weight and body mass index changes, and related complications (gastroesophageal reflux, pneumonia, ulcer, feeding tube obstruction, or dislocation) were documented. Comparison between patients with prolonged (>28 days, group A) and short duration (≤28 days, group B) of EN through nasogastric tube was performed. Data expressed as mean?±?SD or median (min; max) values as appropriate, and analyzed by ANOVA repeated measures and Kaplan-Meier estimates. We identified 114 patients who fulfilled the inclusion criteria. Among them, 10% were treated with radiotherapy alone, while 90% received concurrent chemotherapy or cetuximab. Ninety-four patients (82%, group A) had a nasogastric tube in place for a period >28 days and 20 (18%, group B) for ≤28 days during treatment. Patients were mainly men (86 patients, 75%), with a median age of 61 years (range 49–73) and advanced stage IV disease in most cases (87 patients, 76%) without differences between both groups (p = 0.53, 0.47, and 0.30, respectively). Treatment discontinuation did not occur within both groups. Fifty-six patients (49%) developed complications, without a significant difference between both groups (P = 0.23). Body weight and BMI changes did not differ during EN (–0.8?±?4.5 and –0.3?±?1.6), the oncological treatment (–5.3?±?4.0 and –1.8?±?1.4), or 6 months after the end of treatment (–0.6?±?4.4 and –0.2?±?1.5). Our findings suggest that prolonged enteral nutrition by nasogastric tube is safe and effective in preventing weight loss during curative radiotherapy or radio-chemotherapy for head and neck cancer.     

Effect of free iron on collagen synthesis,cell proliferation and MMP-2 expression in rat hepatic stellate cells

Various studies on hepatic fibrosis occurring in iron overload suggest that excess of tissue iron may be involved in the stimulation of collagen synthesis. Anyway, up to date, direct evidence on the role of iron in hepatic fibrosis is lacking. Moreover, it is not clear whether iron acts as direct initiator of fibrogenesis or as mediator of hepatocellular necrosis. In the present study, we investigated the effect of nontoxic doses of iron on collagen metabolism and proliferation, key features of liver fibrosis, by means of cultures of hepatic stellate cells, the liver cells responsible for collagen production. Iron treatment increased collagen synthesis without affecting noncollagen proteins. The maximum effect was observed at 5 microM iron (+132%). At this dose, no cell damage or proliferation was detected. Conversely, higher doses of iron (10 and 25 microM) induced cell proliferation and a lower increase in collagen synthesis, suggesting the prevalence of proliferative effect on the synthetic one. These effects occurred without the intervention of serum factors and were not mediated by lipid peroxidation. Our results strongly support the hypothesis that iron "per sé" may act as a profibrogenic agent. Finally, we provide evidence that iron plays a role also in matrix degradation, by stimulating some metalloprotease activities. Iron treatment increased metalloprotease-2 activity in hepatic stellate cells, while no changes were observed for interstitial collagenase activity suggesting that, in these conditions, a pathological accumulation of hepatic extracellular matrix may occur.     

Anti-proliferative and pro-apoptotic activities of hydroxytyrosol on different tumour cells: the role of extracellular production of hydrogen peroxide

Purpose

Several recently published data suggest that the anti-proliferative and pro-apoptotic properties of hydroxytyrosol [3,4-dihydroxyphenyl ethanol (3,4-DHPEA)] on HL60 cells may be mediated by the accumulation of hydrogen peroxide (H₂O₂) in the culture medium. The aim of this study was to clarify the role played by H₂O₂ in the chemopreventive activities of 3,4-DHPEA on breast (MDA and MCF-7), prostate (LNCap and PC3) and colon (SW480 and HCT116) cancer cell lines and to investigate the effects of cell culture medium components and the possible mechanisms at the basis of the H₂O₂-producing properties of 3,4-DHPEA.

Methods

The proliferation was measured by the MTT assay and the apoptosis by both fluorescence microscopy and flow cytometry. The concentration of H₂O₂ in the culture medium was measured by the ferrous ion oxidation–xylenol orange method.

Results

It was found that the H₂O₂-inducing ability of 3,4-DHPEA is completely prevented by pyruvate and that the exposure of cells to conditions not supporting the H₂O₂ accumulation (addition of either catalase or pyruvate to the culture medium) inhibited the anti-proliferative effect of 3,4-DHPEA. Accordingly, the sensitivity of the different cell lines to the anti-proliferative effect of 3,4-DHPEA was inversely correlated with their ability to remove H₂O₂ from the culture medium. With regard to the mechanism by which 3,4-DHPEA causes the H₂O₂ accumulation, it was found that superoxide dismutase increased the H₂O₂ production while tyrosinase, slightly acidic pH (6,8) and absence of oxygen (O₂) completely prevented this activity. In addition, different transition metal-chelating compounds did not modify the H₂O₂-producing activity of 3,4-DHPEA.

Conclusions

The pro-oxidant activity of 3,4-DHPEA deeply influences its ‘in vitro’ chemopreventive activities. The main initiation step in the H₂O₂-producing activity is the auto-oxidation of 3,4-DHPEA by O₂ with the formation of the semiquinone, superoxide ions (O₂ ^?) and 2H⁺.     

Optimization of 4-aminoquinoline/clotrimazole-based hybrid antimalarials: further structure-activity relationships, in vivo studies, and preliminary toxicity profiling

Despite recent progress in the fight against malaria, the emergence and spread of drug-resistant parasites remains a serious obstacle to the treatment of infections. We recently reported the development of a novel antimalarial drug that combines the 4-aminoquinoline pharmacophore of chloroquine with that of clotrimazole-based antimalarials. Here we describe the optimization of this class of hybrid drug through in-depth structure-activity relationship studies. Antiplasmodial properties and mode of action were characterized in vitro and in vivo, and interactions with the parasite's 'chloroquine resistance transporter' were investigated in a Xenopus laevis oocyte expression system. These tests indicated that piperazine derivatives 4b and 4d may be suitable for coadministration with chloroquine against chloroquine-resistant parasites. The potential for metabolism of the drugs by cytochrome P450 was determined in silico, and the lead compounds were tested for toxicity and mutagenicity. A preliminary pharmacokinetic analysis undertaken in mice indicated that compound 4b has an optimal half-life.     

Preparation,characterization and in vitro activities evaluation of solid lipid nanoparticles based on PEG-40 stearate for antifungal drugs vaginal delivery

The present article reports the preparation, characterization and performance evaluation of solid lipid nanoparticles (SLNs) based on polyoxyethylene-40 stearate (PEG-40 stearate) for the administration of antifungal agents such as ketoconazole and clotrimazole. These nanoparticles could be useful in the treatment of vaginal infections sustained by Candida albicans. In particular, PEG-40 stearate was made to react with acryloyl chloride in order to introduce an easily polymerizable moiety for the creation of a second shell and to ensure a slow drug release. In addition, the differences on the release profiles between PEG-40 stearate-based nanoparticles, PEG-40 stearate acrylate based and polymerized ones, were analyzed under conditions, simulating the typical environment of Candida albicans infection. Then, the antifungal activity of nanoparticles was also evaluated in terms of minimal inhibitory concentration. Moreover, the nanoparticles were submitted to in vitro studies for evaluating the drug permeability at the site of action. Results indicated that the obtained particles are potentially useful for the treatment of vaginal infections sustained by Candida albicans.     

Changes in Biliary Levels of Arginine and its Methylated Derivatives after Hepatic Ischaemia/Reperfusion

Arginine (Arg) can be methylated to form symmetrical dimethylarginine (SDMA) and asymmetrical dimethylarginine (ADMA), the latter an endogenous inhibitor of nitric oxide synthase (NOS). SDMA is excreted in the urine, while ADMA is mainly subjected to degradation in the liver. Arg competes with ADMA and SDMA for cellular transport across cationic amino‐acid transporters (CATs). We evaluated the changes in serum, tissue and biliary levels of Arg, citrulline (Cit), ADMA and SDMA and the modifications in CATs after ischaemia‐reperfusion (I/R). Male Wistar rats were subjected to 30‐min. partial‐hepatic ischaemia or sham‐operated. After 60‐min. reperfusion, the concentrations of ADMA, SDMA, Arg and Cit in serum, tissue and bile were measured. Serum levels of AST, ALT and alkaline phosphatase (AP) levels were determined. mRNA of cationic transporter 2A (CAT‐2A) and 2B (CAT‐2B) were also quantified. An increase in ADMA and a decrease in SDMA were observed in bile at the end of reperfusion. On the contrary, lower tissue ADMA levels and higher SDMA levels were quantified. No serum changes in ADMA and SDMA were found. A decrease in Arg and an increase of Cit were detected in serum, bile and tissue after I/R. A marked increase in AST, ALT and AP levels in serum confirmed I/R injury. A decrease in mRNA transporter CAT‐2A but not in CAT‐2B was detected. This study supported a biliary CAT‐2B–dependent transport of ADMA and demonstrated, for the first time, that the liver is also responsible for the biliary excretion of SDMA into the bile.     

Effects of prostaglandin A1 on renal handling of salt and water in congestive heart failure

Prostaglandin A1 (PGA1) was infused at the rate of 1/microgram/kg/min in 10 patients with decompensated heart failure under conditions of water loading (5 patients) or water deprivation (5 patients). During water loading, PGA1 increased urinary excretion of sodium, potassium, chloride, calcium, and magnesium, as well as free-water clearance. During water deprivation, it increased free-water reabsorption. Gomerular filtration rate was increased slightly by PGA1 only when it was given with an infusion of hypertonic mannitol during water deprivation. This selective action of PGA1, which increased the excretion but not the reabsorption of free water, suggests its use to correct certain hypo-osmolar conditions. The site of action of PGA1 on the kidney seems to be in the tubules and mainly in the proximal tubules. These findings might be important in the understanding of the role of renal prostaglandins.     

In vitro activities of the lipopeptides palmitoyl (Pal)-Lys-Lys-NH(2) and Pal-Lys-Lys alone and in combination with antimicrobial agents against multiresistant gram-positive cocci

The in vitro activities of the lipopeptides palmitoyl (Pal)-Lys-Lys-NH(2) and Pal-Lys-Lys against gram-positive cocci were investigated. Enterococci and streptococci demonstrated higher susceptibilities than staphylococci and Rhodococcus equi. A positive interaction was shown when the lipopeptides were combined with beta-lactams and vancomycin. These results suggest that lipopeptides are promising candidates for antimicrobial therapy for infections caused by gram-positive organisms.     

Congenital pathology of the pituitary gland and parasellar region

The adenohypophysis and neurohypophysis originate from the combination of 2 events occurring during the fourth week of life, the development of Rathke pouch and of a neuroectodermal evagination of tissue from the floor of the diencephalon. Congenital pathology of the pituitary gland and parasellar regions derives from abnormalities of these coordinated events. In this article, we review the pathogenesis, clinical presentation, and imaging features of common and rare congenital disorders of the region of the sella turcica.