42 research outputs found

    New insights into the cystine-sulfite reaction

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    The mechanism by which cysteine-S-sulfate is formed from the reaction of sulfite with cystine in the absence of a dedicated oxidizing agent is investigated using high-resolution NMR. Changes to reactant ratio, pH, UV light exposure and temperature were evaluated to determine the most effective conditions to achieve the maximum yield of cysteine-S-sulfate without recourse to conventional oxidizing reagents. Herein evidence is provided for both nucleophilic and radical mechanisms, by which cysteine-S-sulfate can be generated with yields of up to 96%

    Typical edible non-dairy animal products in Africa from local animal resources

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    This review aims to identify the main typical non-dairy edible products of animal origin available in Africa, describing their production processes and their strengths and constraints. Farm animals are mainly raised in an extensive, family-run system; there is, however, a significant development of intensive poultry production. Meat products are usually obtained by drying, but meat and/or offal can also be stored as stuffed products and can be additionally treated by smoking and/or curing. The increasing poultry production provides eggs and meat at low price. The small-scale/ family farms are managed mainly by women and children, with a positive social impact. The assets and limits of local breeds and of extensive versus semi-extensive or intensive production systems are discussed. Seafood are an essential source of proteins, minerals and micronutrients. Due its high perishability, the proportion of cured fish in this continent is higher than the world average. Wildlife can supply high-quality meat, but attention must be paid to the vulnerable/ endangered species and to the sanitary aspects of this food chain. Insects are traditionally con- sumed in Africa, supplying very cheap highly nutritive food, with low environmental impact. Finally, a variety of honey and other bee products, including some Slow Food praesidia, are described. From the point of view of the respect of biodiversity and ecosystems, local culture, accessibility and nutritional requirements, animal productions in Africa are usually carried out in a sustainable way; however, the low efficiency of most traditional production systems represents an important limit, also in relation to export opportunities

    The preoperative serum ratio of total prostate specific antigen (PSA) to free testosterone (FT), PSA/FT index ratio, and prostate cancer. Results in 220 patients undergoing radical prostatectomy

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    Objectives: To evaluate associations of preoperative total prostate specific antigen (PSA) to free testosterone (FT), the PSA/FT index ratio, with features of pathology prostate cancer (PCA) and to investigate its prognostic potential in clustering the PCA population. Patients and methods: After excluding criteria, the records of 220 patients who underwent radical prostatectomy (RP) were retrospectively reviewed. Serum samples of PSA, total testosterone (TT) and FT were collected at 8.00 A.M., one month after biopsies and before RP. The PSA/FT ratio was computed in the population of patients who were clustered in groups according to ranking intervals of the PSA/FT ratio which identified at least 4 clusters which were coded as A, B, C, and D. The independent associations of the PSA/FT index ratio were assessed by statistical methods and a two-sided P < 0.05 was considered to indicate statistical significance. Results: TT correlated to FT which was a significant predictor of PSA in the population of patients who were subsequently clustered, according to increasing interval values of the PSA/FT index ratio, in groups that showed a stronger linear association of FT with PSA. The PSA/FT index ratio significantly associated with pathology features of prostate cancer such as pathology Gleason score (pGS), invasion of the seminal vesicles (pT3b), proportion of positive cores (P+) and proportion of cancer involving the volume of the prostate. In the population of patients, TT, PSA/FT index ratio and P+ independently associated with pGS 65 7 and pT3b; moreover, the odds ratio (OR) of the PSA/FT index ratio resulted 9.11 which was stronger than TT (OR = 1.11) and P+ (OR = 8.84). In the PCA population, TT, PSA/FT index ratio and P+ also independently associated with pT3b PCA; interestingly, the OR of PSA/FT index resulted 54.91 which was stronger than TT (OR = 1.31) and P+ (26.43). Conclusions: Preoperative PSA/FT index ratio is an independent strong factor which directly associates with aggressive features of pathology PCA; moreover, it might express prognostic potential for clustering the patient population in risk classes. Confirmatory studies are required

    The Natural Compound Climacostol as a Prodrug Strategy Based on pH Activation for Efficient Delivery of Cytotoxic Small Agents

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    We synthesized and characterized MOMO as a new small molecule analog of the cytotoxic natural product climacostol efficiently activated in mild extracellular acidosis. The synthesis of MOMO had a key step in the Wittig olefination for the construction of the carbon-carbon double bond in the alkenyl moiety of climacostol. The possibility of obtaining the target (Z)-alkenyl MOMO derivative in very good yield and without presence of the less active (E)-diastereomer was favored from the methoxymethyl ether (MOM)-protecting group of hydroxyl functions in aromatic ring of climacostol aldehyde intermediate. Of interest, the easy removal of MOM-protecting group in a weakly acidic environment allowed us to obtain a great quantity of climacostol in biologically active (Z)-configuration. Results obtained in free-living ciliates that share the same micro-environment of the climacostol natural producer Climacostomum virens demonstrated that MOMO is well-tolerated in a physiological environment, while its cytotoxicity is rapidly and efficiently triggered at pH 6.3. In addition, the cytostatic vs. cytotoxic effects of acidified-MOMO can be modulated in a dose-dependent manner. In mouse melanoma cells, MOMO displayed a marked pH-sensitivity since its cytotoxic and apoptotic effects become evident only in mild extracellular acidosis. Data also suggested MOMO being preferentially activated in the unique extra-acidic microenvironment that characterizes tumoural cells. Finally, the use of the model organism Drosophila melanogaster fed with an acidic diet supported the efficient activity and oral delivery of MOMOmolecule in vivo.MOMO affected oviposition ofmating adults and larvae eclosion. Reduced survival of flies was due to lethality during the larval stages while emerging larvae retained their ability to develop into adults. Interestingly, the gut of eclosed larvae exhibited an extended damage (cell death by apoptosis) and the brain tissue was also affected (reduced mitosis), demonstrating that orally activated MOMO efficiently targets different tissues of the developing fly. These results provided a proof-of-concept study on the pHdependence of MOMO effects. In this respect, MOM-protection emerges as a potential prodrug strategy which deserves to be further investigated for the generation of efficient pH-sensitive small organic molecules as pharmacologically active cytotoxic compounds

    Reversal of Defective Mitochondrial Biogenesis in Limb-Girdle Muscular Dystrophy 2D by Independent Modulation of Histone and PGC-1α Acetylation

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    Mitochondrial dysfunction occurs in many muscle degenerative disorders. Here, we demonstrate that mitochondrial biogenesis was impaired in limb-girdle muscular dystrophy (LGMD) 2D patients and mice and was associated with impaired OxPhos capacity. Two distinct approaches that modulated histones or peroxisome proliferator-activated receptor-gamma coactivator 1 \u3b1 (PGC-1\u3b1) acetylation exerted equivalent functional effects by targeting different mitochondrial pathways (mitochondrial biogenesis or fatty acid oxidation[FAO]). The histone deacetylase inhibitor Trichostatin A (TSA) changed chromatin assembly at the PGC-1\u3b1 promoter, restored mitochondrial biogenesis, and enhanced muscle oxidative capacity. Conversely, nitric oxide (NO) triggered post translation modifications of PGC-1\u3b1 and induced FAO, recovering the bioenergetics impairment of muscles but shunting the defective mitochondrial biogenesis. In conclusion, a transcriptional blockade of mitochondrial biogenesis occurred in LGMD-2D and could be recovered by TSA changing chromatin conformation, or it could be overcome by NO activating a mitochondrial salvage pathway

    Nitric Oxide Generated by Tumor-Associated Macrophages Is Responsible for Cancer Resistance to Cisplatin and Correlated With Syntaxin 4 and Acid Sphingomyelinase Inhibition

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    Tumor microenvironment is fundamental for cancer progression and chemoresistance. Among stromal cells tumor-associated macrophages (TAMs) represent the largest population of infiltrating inflammatory cells in malignant tumors, promoting their growth, invasion, and immune evasion. M2-polarized TAMs are endowed with the nitric oxide (NO)-generating enzyme inducible nitric oxide synthase (iNOS). NO has divergent effects on tumors, since it can either stimulate tumor cells growth or promote their death depending on the source of it; likewise the role of iNOS in cancer differs depending on the cell type. The role of NO generated by TAMs has not been investigated. Using different tumor models in vitro and in vivo we found that NO generated by iNOS of M2-polarized TAMs is able to protect tumor cells from apoptosis induced by the chemotherapeutic agent cisplatin (CDDP). Here, we demonstrate that the protective effect of NO depends on the inhibition of acid sphingomyelinase (A-SMase), which is activated by CDDP in a pathway involving the death receptor CD95. Mechanistic insights indicate that NO actions occur via generation of cyclic GMP and activation of protein kinase G (PKG), inducing phosphorylation of syntaxin 4 (synt4), a SNARE protein responsible for A-SMase trafficking and activation. Noteworthy, phosphorylation of synt4 at serine 78 by PKG is responsible for the proteasome-dependent degradation of synt4, which limits the CDDP-induced exposure of A-SMase to the plasma membrane of tumor cells. This inhibits the cytotoxic mechanism of CDDP reducing A-SMase-triggered apoptosis. This is the first demonstration that endogenous NO system is a key mechanism through which TAMs protect tumor cells from chemotherapeutic drug-induced apoptosis. The identification of the pathway responsible for A-SMase activity downregulation in tumors leading to chemoresistance warrants further investigations as a means to identify new anti-cancer molecules capable of specifically inhibiting synt4 degradation

    Investigation of the Formation of Squalene Oligomers Exposed to Ultraviolet Light and Changes in the Exposed Squalene as a Potential Skin Model

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    UV-induced oligomerisation of squalene was undertaken to indicate the potential for squalene-containing biological systems to exhibit rheology changes. DOSY NMR enabled the determination of the molecular weight (MW) range using Stokes–Einstein Gierer–Wirtz Estimation (SEGWE Calculator, University of Manchester). This approach was validated by Atmospheric Solids Analysis Probe Time of Flight Mass Spectrometry (ASAP TOF MS). To demonstrate the principle, both benzoyl peroxide and AIBN were used, separately, to initiate rapid, radical oligomerisation. Subsequent experiments in the absence of initiators compared the influence of UV wavelength and time on the resulting oligomer formation. To further model a relevant biological implication of this potentially chaotic UV oligomerisation, both saturated and unsaturated free fatty acids were added to squalene and exposed to UV at 285 nm and 300 nm to determine if cross oligomerisation could be observed. This representation of sebum evidenced the formation of a distribution of higher MW oligomers. Internal viscosity was normalised using the DMSO solvent, but to confirm that changes in rheology did not affect diffusion, a final experiment where fresh squalene was added to our oligomer mixture, representative of sebum, showed that unchanged squalene possessed the anticipated monomeric diffusion coefficient and hence MW. This work suggests, at least qualitatively, that UV-induced squalene oligomerisation can occur over time and that this may have a role in the behaviour of squalene on the skin
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