Biomedical subjects

Giovanni Dugo

Publications and source records attributed to Giovanni Dugo.

28 records · Page 2Linked to original sources

PubMed2004

Fast GC analysis with a 50 microm ID column: theory, practical aspects, and application to a highly complex sample.

This research focuses on the minimization of GC analysis times through the use of a 5 m x 0.05 mm ID x 0.05 microm (film thickness) column. Experimental minimum plate height (Hmin) and optimum linear velocity values were derived from standard compound applications, under various analytical conditions, and then related to classical chromatographic theory. Deviations from the latter are measured and discussed. Practical aspects linked to the use of such capillaries, such as column sample capacity and detector acquisition rates, are also considered. Furthermore, a fast, and what can be considered a very fast method, were applied to the separation of a fuel sample. Coefficients of variation of elution times and relative peak areas were calculated in the very fast application. All analytical results are compared with those obtained by conventional 0.25 mm ID column applications.

Journal Article↗

PubMed2004

Effect of anthocyanins contained in a blackberry extract on the circulatory failure and multiple organ dysfunction caused by endotoxin in the rat.

Anthocyanins are a group of naturally occurring phenolic compounds related to the colouring of plants, flowers and fruits. These pigments are important as quality indicators, chemotaxonomic markers and for their antioxidant activities. Here we have investigated the therapeutic efficacy of anthocyanins contained in a blackberry extract on (i) circulatory failure, (ii), multiple organ dysfunction and (iii) activity of the inducible isoforms of nitric oxide (NO) synthase (iNOS) and cyclooxygenase (COX-2) in anaesthetised rats with endotoxic shock. In a model of endotoxic shock induced by lipopolysaccharide (LPS, E. coli, 10 mg/kg, i.v.) in the rat, pretreatment with anthocyanins present in the blackberry extract (5 mg/kg, i. v. 30 min before LPS) prevented the hypotension induced by LPS. Endotoxaemia also caused rises in the serum levels of (i) glutamyl oxaloacetic transaminase (GOT), glutamyl pyruvic transaminase (GPT), alkaline phosphates and bilirubin (hepatic dysfunction) (ii) creatinine (renal dysfunction), (iii) amylase and lipase (pancreatic injury), (iii) NOx and 6-keto-PGF1 alpha. Anthocyanins attenuated the hepatic and pancreatic injury, the renal dysfunction and decreased NOx and 6-keto-PGF1 alpha levels. Endotoxaemia for 6 h resulted in a substantial increase in iNOS and COX activity in rat lung, which was attenuated in rats pretreated with anthocyanins. Moreover, anthocyanins (0.02 - 0.32 mg/mL) inhibited in vitro iNOS and COX activity from lung of LPS-treated rats. Polymorphonuclear (PMN) infiltration (myeloperoxidase activity), lipid peroxidation (malondialdehyde levels), as well as tissue injury (histological examination) induced by LPS in rat lung and ileum was reduced by anthocyanins (5 mg/kg, i. v. 30 min before LPS). Furthermore, endotoxaemia induced the formation of nitrotyrosine and poly(ADP-ribose) synthetase (PARS) activation as determined by immunohistochemical analysis of lung and ileum tissues. The degree of staining was lowered by anthocyanin treatment. These results indicate that the anthocyanins contained in the blackberry extract exert multiple protective effects in endotoxic shock.

Animals↗

PubMed2004

Fast GC for the analysis of citrus oils.

In this investigation, the gas chromatographic (GC) analysis of citrus essential oils is carried out in 3.3 min, with a speed gain of almost 14 times in comparison with traditional GC procedures. The fast method that is developed requires the application of severe experimental conditions (accelerated temperature program rates, high inlet pressures, and split ratios) and, thus, the support of adequate instrumentation. The samples investigated can be considered to be rather complex and, although a slight loss in peak resolution is observed, the overall analytical result is excellent. All data obtained are compared with that of a conventional application on the same matrices. This is done in order to evaluate the effectiveness and advantages of fast GC achieved with narrow bore columns.

Chromatography, Gas↗

PubMed2003

Retention time reproducibility in comprehensive two-dimensional gas chromatography using cryogenic modulation. II. An interlaboratory study.

An interlaboratory survey was conducted to determine the reproducibility of retention times in both the first (1D) and second dimension (2D) axes of the two-dimensional separation space, using the longitudinal cryogenic modulation comprehensive two-dimensional gas chromatographic approach. Intralaboratory reproducibility has been demonstrated in part 1 of this investigation [J. Chromatogr. A 968 (2002) 161]. Confidence in absolute retention times (hence component positions) in the two-dimensional separation space is critical to component identification. Comparing data from four independent laboratories, five independent gas chromatographs, five independent LMCS units, and numerous operators has determined that the LMCS cryogenic modulation approach provides reliable comprehensive two-dimensional GC results.

Chromatography, Gas↗

PubMed2003

Detailed analysis and group-type separation of natural fats and oils using comprehensive two-dimensional gas chromatography.

Comprehensive gas chromatography (GC x GC) is an adequate methodology for the separation and identification of very complex samples. It is based on the coupling of two capillary columns that each give a different but substantial contribution to the unprecedented resolving power of this technique. The 2D space chromatograms that derive from GC x GC analysis have great potential for identification. This is due to the fact that the contour plot positions, pinpointed by two retention time coordinates, give characteristic patterns for specific families of compounds that can be mathematically translated. This investigation concerned the application of this principle to fatty acid methyl esters that were grouped on an equal double bond number basis. The ester samples were derived from various lipids and all underwent bidimensional analysis on two sets of columns. Peak attribution was supported by mass spectra, linear retention indices and information reported in the literature.

Chromatography, Gas↗

PubMed2003

Comparison of fast and conventional GC analysis for citrus essential oils.

This investigation concerns the application of fast GC in the analysis of essential oils. These are complex matrixes that usually undergo GC separation with conventional methods involving long columns, slow programmed temperature rates, and consequently, a high cost in terms of time. Fast GC techniques are based on the use of narrow bore capillary columns that allow the achievement of high-speed separations on complex samples while maintaining excellent resolution. This work saw the application of two methods on five different citrus essential oils and the comparison of all the results obtained.

Chromatography, Gas↗

PubMed2003

Protective effects of cyanidin-3-O-glucoside from blackberry extract against peroxynitrite-induced endothelial dysfunction and vascular failure.

Anthocyanins are a group of naturally occurring phenolic compounds as colorants in several plants, flowers and fruits. These pigments have a great importance as quality indicators, as chemotaxonomic markers and antioxidants. The content of blackberry (Rubus species) juice was investigated by HPLC/ESI/MS using narrow bore HPLC columns. Using this method we demonstrated that cyanidin-3-O-glucoside represents about 80% of the total anthocyanin contents in blackberry extract. Here we investigated antioxidant activity of the blackberry juice and cyanidin-3-O-glucoside on the endothelial dysfunction in cells and in vascular rings exposed to peroxynitrite. In human umbilical vein endothelial cells (HUVEC) in vitro, peroxynitrite caused a significant suppression of mitochondrial respiration (38 +/- 2.1% of control cells), as measured by the mitochondrial-dependent conversion of the dye MTT to formazan. Peroxynitrite caused DNA strand breakage (63 +/- 1.9% single strand vs 3 +/- 0.9% single strand in control cells), as measured by the alkaline unwinding assay, and caused an activation of PARS, as measured by the incorporation of radiolabeled NAD(+) to nuclear proteins. Blackberry juice (different dilutions that contained 80 ppm;40 ppm;14.5 ppm of cyanidin-3-O-glucoside) and cyanidin-3-O-glucoside (as chloride) (0.085 microM; 0.028 microM; 0.0085 microM) reduced the peroxynitrite-induced suppression of mitochondrial respiration, DNA damage and PARS activation in HUVECs. Vascular rings exposed to peroxynitrite exhibited reduced endothelium-dependent relaxant responses in response to acetylcholine as well as a vascular contractility dysfunction in response to norepinephrine. The development of this peroxynitrite-induced vascular dysfunction was ameliorated by the blackberry juice (different dilutions that contained 80 ppm;40 ppm;14.5 ppm of cyanidin-3-O-glucoside) and cyanidin-3-O-glucoside (as chloride) (0.085 microM;0.028 microM;0.0085 microM). In conclusion our findings clearly demonstrate that blackberry juice containing cyanidin-3-O-glucoside is a scavenger of peroxynitrite and that exert a protective effect against endothelial dysfunction and vascular failure induced by peroxynitrite.

Anthocyanins↗

PubMed2003

Characterization of the anthocyanin fraction of sicilian blood orange juice by micro-HPLC-ESI/MS.

Anthocyanins of red orange juices were analyzed by micro-HPLC coupled on-line with an MS detector equipped with an ESI source. The use of microcolumn HPLC greatly enhanced detection performance, allowing direct identification of the anthocyanins present in the orange juices. The use of a soft ionization technique allows detection of the molecular ions of the aglycons. Eight components were identified, five of them for the first time in red orange juice. Three additional anthocyanins were detected, of which only the aglycon was identified.

Anthocyanins↗

PubMed2003

Protective effects of anthocyanins from blackberry in a rat model of acute lung inflammation.

Anthocyanins are a group of naturally occuring phenolic compounds related to the coloring of plants, flowers and fruits. These pigments are important as quality indicators, as chemotaxonomic markers and for their antioxidant activities. Here, we have investigated the therapeutic efficacy of anthocyanins contained in blackberry extract (cyanidin-3-O-glucoside represents about 80% of the total anthocyanin contents) in an experimental model of lung inflammation induced by carrageenan in rats. Injection of carrageenan into the pleural cavity elicited an acute inflammatory response characterized by fluid accumulation which contained a large number of neutrophils as well as an infiltration of polymorphonuclear leukocytes in lung tissues and subsequent lipid peroxidation, and increased production of nitrite/nitrate (NOx) and prostaglandin E2 (PGE2). All parameters of inflammation were attenuated in a dose-dependent manner by anthocyanins (10, 30 mg kg(-1) 30 min before carrageenan). Furthermore, carrageenan induced an upregulation of the adhesion molecule ICAM-1, nitrotyrosine and poly (ADP-ribose) synthetase (PARS) as determined by immunohistochemical analysis of lung tissues. The degree of staining was lowered by anthocyanins treatment. Thus, the anthocyanins contained in the blackberry extract exert multiple protective effects in carrageenan-induced pleurisy.

Acute Disease↗

PubMed2002

Characterisation of lavender essential oils by using gas chromatography-mass spectrometry with correlation of linear retention indices and comparison with comprehensive two-dimensional gas chromatography.

Nine samples of lavender essential oil were analysed by GC-MS using low-polarity and polar capillary columns. Linear retention indices (LRI) were calculated for each component detected. Characterisation of the individual components making up the oils was performed with the use of an mass spectrometry (MS) library developed in-house. The MS library was designed to incorporate the chromatographic data in the form of linear retention indices. The MS search routine used linear retention indices as a post-search filter and identification of the "unknowns" was made more reliable as this approach provided two independent parameters on which the identification was based. Around 70% of the total number of components in each sample were reliably characterised. A total of 85 components were identified. Semi-quantitative analysis of the same nine samples was performed by gas chromatography (GC) with flame ionisation detection (FID). The identified components accounted for more than 95% of each oil. By comparing the GC-MS results with the results from the GCxGC-FID analysis of a lavender essential oil, many more components could be found within the two-dimensional separation space.

Chromatography, Gas↗