Functions of vasopressin and oxytocin in bone mass regulation.

Prior studies show that oxytocin (Oxt) and vasopressin (Avp) have opposing actions on the skeleton exerted through high-affinity G protein-coupled receptors. We explored whether Avp and Oxtr can share their receptors in the regulation of bone formation by osteoblasts. We show that the Avp receptor 1α (Avpr1α) and the Oxt receptor (Oxtr) have opposing effects on bone mass: Oxtr(-/-) mice have osteopenia, and Avpr1α(-/-) mice display a high bone mass phenotype.

Highly selective palladium-benzothiazole carbene-catalyzed allylation of active methylene compounds under neutral conditions.

The Pd-benzothiazol-2-ylidene complex I was found to be a chemoselective catalyst for the Tsuji-Trost allylation of active methylene compounds carried out under neutral conditions and using carbonates as allylating agents. The proposed protocol consists in a simplified procedure adopting an in situ prepared catalyst from Pd2dba3 and 3-methylbenzothiazolium salt V as precursors. A comparison of the performance of benzothiazole carbene with phosphanes and an analogous imidazolium carbene ligand is also proposed.

MALDI-TOF MS for quality control of high protein content sport supplements.

High protein content sport nutritional supplements are found as powder products containing, as ingredients, amino acids and proteins with important nutritional values as milk, soy and egg proteins. An EU Food Supplements Directive (2002) requires that supplements should be safe, both in dosages and in purity. It is important, then, to develop rapid and sensitive methods to be employed for the quality control of these substances.

Osteoblast regulation via ligand-activated nuclear trafficking of the oxytocin receptor.

We report that oxytocin (Oxt) receptors (Oxtrs), on stimulation by the ligand Oxt, translocate into the nucleus of osteoblasts, implicating this process in the action of Oxt on osteoblast maturation. Sequential immunocytochemistry of intact cells or isolated nucleoplasts stripped of the outer nuclear membrane showed progressive nuclear localization of the Oxtr; this nuclear translocation was confirmed by monitoring the movement of Oxtr-EGFP as well as by immunogold labeling. Nuclear Oxtr localization was conclusively shown by Western immunoblotting and MS of nuclear lysate proteins.

Development of a direct in-matrix extraction (DIME) protocol for MALDI-TOF-MS detection of glycated phospholipids in heat-treated food samples.

In foodstuffs, one of the main factors inducing modifications in phospholipids (PLs) structure is the heat treatment. Among PLs, only phosphatidylethanolamines and phosphatidylserines, due to their free amino group, can be involved in Maillard reaction and can form adducts with reducing sugars, besides other by-products called advanced glycation end-products. To date, glycated lipid products are less characterized in comparison to proteins.

Determination of hidden hazelnut oil proteins in extra virgin olive oil by cold acetone precipitation followed by in-solution tryptic digestion and MALDI-TOF-MS analysis.

Adulteration of extra-virgin olive oil (EVOO) with hazelnut oil (HO) is an illegal practice that could have severe health consequences for consumers due to the possible exposure to hidden hazelnut allergens. Here, matrix-assisted laser-desorption/ionization (MALDI) mass spectrometry (MS) was used as a rapid and sensitive technique for the detection of a low concentration of hazelnut proteins in oil samples. Different protocols were tested for protein extraction, and the most efficient (cold acetone) was applied to HO and EVOO adulterated with HO.

Proteomic analysis of complex protein samples by MALDI-TOF mass spectrometry.

MALDI MS has become a technique of considerable impact on many fields, from proteomics to lipidomics, including polymer analysis and, more recently, even low molecular weight analytes due to the introduction of matrix-less ionization techniques (e.g., DIOS) or new matrices such as ionic liquids, proton sponges, and metal nanoparticles.

MALDI-TOF mass spectrometric determination of intact phospholipids as markers of illegal bovine milk adulteration of high-quality milk.

In the dairy industry one of the most common frauds is mixing high-value milk (sheep's and goats') with milk of lower value (cows'). This illegal practice has commercial, ethical, and serious sanitary consequences because consumers can be exposed to hidden allergens contained in the undeclared cows' milk. Here, we investigated the possibility of using matrix-assisted laser-desorption/ionization (MALDI)-time of flight (TOF) mass spectrometry (MS) as a rapid, sensitive, and accurate technique for detection of milk adulteration by analysis of phospholipid profiles.

MALDI-TOF mass spectrometry detection of extra-virgin olive oil adulteration with hazelnut oil by analysis of phospholipids using an ionic liquid as matrix and extraction solvent.

The adulteration of extra virgin olive oil (EVOO) with hazelnut oil (HO) is frequent and constitutes a serious concern both for oil suppliers and consumers. The high degree of similarity between the two oils as regards triacylglycerol, total sterol and fatty acid profile, complicates the detection of low percentages of HO in EVOO. However, phospholipids (PLs) are usually present in seed oils at a concentration range of 10-20 g/kg, while the amounts of PLs in VOOs are 300-400 times lower.

Detection of sheep and goat milk adulterations by direct MALDI-TOF MS analysis of milk tryptic digests.

In dairy field, one of the most common frauds is the adulteration of higher value types of milk (sheep's and goat's) with milk of lower value (cow's milk). This illegal practice has an economic advantage for milk producers and poses a threat for consumers' health because of the presence of hidden allergens as, for example, cow milk proteins, in particular, α(s1)-casein and β-lactoglobulin. The urgent need of sensitive techniques to detect this kind of fraud brought to the development of chromatographic, immunoenzymatic, electrophoretic and mass spectrometric assays.

Lipid fingerprinting of gram-positive lactobacilli by intact--matrix-assisted laser desorption/ionization mass spectrometry using a proton sponge based matrix.

A method of direct lipid analysis by matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS) in intact membranes, without prior extraction/separation steps, is described. Here, we demonstrate the efficacy of a strong base, 1,8-bis(dimethylamino)naphthalene (DMAN; proton sponge), as a novel matrix for MALDI-time-of-flight (TOF) MS analysis of whole cell bacteria. Initially, individual acidic low-molecular-weight analytes such as standard free fatty acids and phospholipids were analyzed using DMAN as matrix.

Detection of hazelnut oil in extra-virgin olive oil by analysis of polar components by micro-solid phase extraction based on hydrophilic liquid chromatography and MALDI-ToF mass spectrometry.

The oil polar fraction may have a great potential for the characterization of vegetable oils and for the individuation of adulterations. In particular, adulteration of extra-virgin olive oil (EVOO) with hazelnut oil (HO) is one of the most difficult ones to detect due to the similar composition as regards triacylglycerol, total sterol and fatty acid profile. A new micro-solid phase extraction (µ-SPE) procedure based on hydrophilic liquid chromatography (HILIC) micro-columns was developed for the selective extraction and enrichment of polar compounds from EVOO and HO before matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-ToF-MS) analysis.

Selective extraction of phospholipids from dairy products by micro-solid phase extraction based on titanium dioxide microcolumns followed by MALDI-TOF-MS analysis.

A new micro-solid phase extraction (micro-SPE) procedure based on titanium dioxide microcolumns was developed for the selective extraction of phospholipids (PLs) from dairy products before matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) analysis. All the extraction steps (loading, washing, and elution) have been optimized using a synthetic mixture of PLs standard and the procedure was subsequently applied to food samples such as milk, chocolate milk and butter. The whole method demonstrated to be simpler than traditional approaches and it appears very promising for a rapid PLs screening and characterization also in biological matrices.

Solid-phase microextraction-gas chromatography mass spectrometry and multivariate analysis for the characterization of roasted coffees.

HS-SPME-GC-MS in combination with PCA was employed to discriminate different arabica/robusta blends having different geographical origins. HS-SPME confirmed to be an effective and reproducible sampling technique for routine characterization of coffees. In addition, the chemometric approach permitted to find parameters suitable for the differentiation of the different blends and the determination of the real quality of the products.

A matrix assisted laser desorption ionization time-of-flight mass spectrometry investigation to assess the composition of cod liver oil based products which displayed a different in vivo allergenic power.

Cod liver oil is a well-known "nutraceutical", which contains a wide range of substances, including triacylglycerols (TAGs), mono- and di-acylglycerols, free fatty acids, vitamins and n-3 polyunsaturated fatty acids. Topically applied, cod liver oil contributes to faster wound healing and improvement in skin quality. We recently reported a case of allergic contact dermatitis to cod liver oil contained in a topical ointment, in whom the patch test reaction with the ointment containing cod liver oil at a concentration of 40% was stronger than the reaction induced by a pure cod liver oil at the same concentration.

Assessment of lectin and HILIC based enrichment protocols for characterization of serum glycoproteins by mass spectrometry.

Protein glycosylation is a common post-translational modification that is involved in many biological processes, including cell adhesion, protein-protein and receptor-ligand interactions. The glycoproteome constitutes a source for identification of disease biomarkers since altered protein glycosylation profiles are associated with certain human ailments. Glycoprotein analysis by mass spectrometry of biological samples, such as blood serum, is hampered by sample complexity and the low concentration of the potentially informative glycopeptides and -proteins.

Determination of ochratoxin A in green coffee beans by solid-phase microextraction and liquid chromatography with fluorescence detection.

A new method for the determination of Ochratoxin A (OTA) in green coffee beans by solid-phase microextraction (SPME) coupled to liquid chromatography with fluorescence detection (LC-FD) is described for the first time. Coffee samples were extracted by a 5% NaHCO(3) solution, followed by a clean-up step of the extract by chloroform partition. The aqueous extract was then acidified and finally subjected to SPME-LC-FD analysis.

Impact of sample preparation in peptide/protein profiling in human serum by MALDI-TOF mass spectrometry.

The low molecular weight (LMW) serum proteome (<15 kDa) is the most generally informative from a medical point of view. Different sample pre-treatment approaches and devices for serum depletion in high-abundant proteins were tested in order to analyze, by MALDI-TOF-MS (both in "linear" and "reflectron" acquisition mode), the serum low molecular weight proteins/peptides. The best results in terms of detected ions number and abundance were obtained by using ultrafiltration of serum on 30 kDa molecular weight cut off membranes followed by miniaturized reverse-phase solid-phase extraction (mu-SPE) as sample pre-treatment; this procedure yielded also satisfactory within-sample and sample-to-sample repeatability (on both m/z values and peak intensity of the main observable ions).

A laser desorption ionization time-of-flight mass spectrometry investigation into triacylglycerols oxidation during thermal stressing of edible oils.

Laser desorption ionization time-of-flight mass spectrometry (LDI-TOF MS) was used to characterize olive and sunflower oils before and after thermally assisted oxidation in order to develop a rapid fingerprinting method for oil that contains unchanged and oxidized components. No matrix was used to assist laser desorption, and simplified mass spectra were obtained in the mass range of interest (m/z 500-1000), where triacyl- and diacylglycerol ions were observed. Sample preparation was reduced to dissolving oil in chloroform saturated with NaCl.

Determination of ochratoxin A in human urine by solid-phase microextraction coupled with liquid chromatography-fluorescence detection.

A new method for the determination of ochratoxin A (OTA) in human urine samples has been developed using solid-phase microextraction (SPME) interfaced with liquid chromatography-fluorescence detection (LC-FD). This method is simpler and cheaper compared to the most widely adopted clean-up procedures for OTA extraction from urine (usually based on immunoaffinity columns). Briefly, urine samples, diluted 1:5 with phosphate buffer (10 mM, pH 3), were partitioned against chloroform and the aqueous phase extracted by a polydimethylsiloxane/divinylbenzene (PDMS/DVB) fiber.

Occupational contact dermatitis to a limonene-based solvent in a histopathology technician.

Recently, D-limonene-based solvents are used as a safe alternative to xylene for histological and cytological application to dissolve paraffin. We report the case of a histopathology technician with a recalcitrant hand contact dermatitis strictly related to the use of a limonene-based solvent agent. Patch tests with SIDAPA (Italian Society of Allergological, Professional and Environmental Dermatology) standard series, limonene-based solvent used by the patient and D- and L-limonene (both oxidized and nonoxidized form) and with Giemsa and methylene blue stains were performed.

Profiling urinary metabolites of naproxen by liquid chromatography-electrospray mass spectrometry.

Glucuronidation, an important metabolic process for the biotransformation of drugs into easily eliminable water-soluble detoxification products, can also lead to biologically active or toxic glucuronide conjugates. The present work describes a liquid chromatography-electrospray mass spectrometry (LC-ESI-MS) approach for the characterization of naproxen and O-6-desmethylnaproxen glucuronides. The method is fast and efficient and permitted to individuate alpha and beta isomers of both naproxen and O-6-desmethylnaproxen glucuronides.

Determination of Ochratoxin A in wine at sub ng/mL levels by solid-phase microextraction coupled to liquid chromatography with fluorescence detection.

Solid-phase microextraction (SPME), using a polydimethylsiloxane/divinylbenzene (PDMS/DVB) fiber, interfaced with liquid chromatography-fluorescence detection (LC-FD) has been applied to the determination of Ochratoxin A (OTA) in wine samples. Compared to the most widely adopted extraction/clean-up procedure based on immunoaffinity columns (IAC), the solventless extraction is simpler and cost-effective, requiring the simple immersion of the fiber in diluted wine samples. Furthermore, a fast LC separation is achieved under isocratic conditions.

Ochratoxin a determination in beer by solid-phase microextraction coupled to liquid chromatography with fluorescence detection: a fast and sensitive method for assessment of noncompliance to legal limits.

A solid-phase microextraction-liquid chromatography-fluorescence detection (SPME-LC-FD) method for the determination of ochratoxin A (OTA) in commercial beer samples was developed for the first time using a 60 microm thick poly(dimethylsiloxane)/divinylbenzene (PDMS/DVB) fiber. The procedure required a very simple sample pretreatment, an isocratic elution, and provides a selective extraction. All of the factors influencing fiber adsorption (extraction time, temperature, pH, and salt addition) and desorption of the analyte (desorption and injection time and desorption solvent mixture composition) have been investigated.