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Biomedical subjects

E Camera

Publications and source records attributed to E Camera.

16 recordsLinked to original sources
PubMed2001

Simultaneous determination of reduced and oxidized glutathione in peripheral blood mononuclear cells by liquid chromatography-electrospray mass spectrometry.

We developed a sensitive and specific liquid chromatography-electrospray mass spectrometric (HPLC-ESI-MS) assay for the simultaneous determination of reduced and oxidized glutathione (GSH and GSSG) in peripheral blood mononuclear cells (PBMC). Following derivatization with N-ethylmaleimide to prevent GSH auto-oxidation, addition of thiosalicylic acid as internal standard, and protein precipitation with cold acetonitrile, the samples were injected into a diol column, eluted with acetonitrile-1% aqueous acetic acid (25:75) and detected by the ESI-MS system. The optimized method exhibited a good detection limit for both analytes (0.01 and 0.05 microM for GSH and GSSG, respectively). Good linearity was reached in the 0.01-20 microM range for GSH and 0.05-20 microM for GSSG. The mean recoveries of GSH and GSSG were 98.5-100.6% and 105.8-111.5%, respectively. The run-to-run repeatability for retention time and peak area was RSD% 0.06 and 1.75 for GSH and 0.18 and 2.50 for GSSG. The optimized method was applied to GSH and GSSG assay in PBMC analyzing 20 healthy individuals.

Chromatography, Liquid↗
PubMed2001

Mitochondrial impairment in peripheral blood mononuclear cells during the active phase of vitiligo.

Several hypotheses have been made about the pathogenesis of vitiligo, and some of them have considered a systemic involvement in the course of the disease. Evidence has been presented on the role of oxidative stress as the initial event in melanocyte degeneration. In accordance with this view, we determined the levels of some antioxidants, i.e., superoxide dismutase, catalase, reduced glutathione, and vitamin E, in erythrocytes and/or peripheral blood mononuclear cells from patients with active or stable vitiligo and from a control group of healthy subjects. In erythrocytes the parameters evaluated were not significantly different. On the contrary, in peripheral blood mononuclear cells, superoxide dismutase activity was increased in both groups of patients, whereas catalase activity, reduced glutathione and vitamin E levels were decreased exclusively in subjects with active disease. The imbalance of antioxidants was associated with hyperproduction of reactive oxygen species due to a mitochondrial impairment as cyclosporin A, an inhibitor of the permeability transition pores opening, significantly reduced the reactive oxygen species production. Moreover an alteration of the mitochondrial transmembrane potential and a higher percentage of apoptotic cells were observed in active vitiligo patients. Based on these results, we suggest that, in vitiligo, mitochondria might be the target of different stimuli, such as reactive oxygen species generation, cytokines production, catecholamine release, alteration of Ca2+ metabolism, all of which capable of inducing melanocyte degeneration.

Adult↗
PubMed2001

Oxidative stress, growth factor production and budding in potato tubers during cold storage.

In order to verify the role played by oxidation in the budding of potato tubers (Solanum tuberosum L. cv. Kennebec), the physiological events occurring below bud at 4 degrees C have been studied for a period of 6 months. The low temperature storage induced an increase in the degree of unsaturation and a decrease in the ratio of saturated/unsaturated fatty acids of membrane polar lipids with a subsequent increase of lipid hydroperoxides (LOOH). Cold stress increased both enzymatic antioxidative activities (superoxide dismutase, SOD, E.C.1.15.1.1; catalase, CAT, E.C.1.11.1.6), and alpha-tocopherol levels thus protecting membrane's polyunsaturated lipids. Between 0 and 15 days of storage SOD/CAT ratio, alpha-tocopherol, LOOH levels and the degree of lipid unsaturation showed strong variations. After 30 to 120/150 days the antioxidative system seemed to reach a homeostasis different from that of time 0, accompanied by a constant increase of indole-3-acetic acid (IAA) after 60 days. The antioxidative system, after 150 days, lost its efficiency while LOOH levels were maintained higher than time 0 and IAA concentration was sufficient to allow sprouting.

Catalase↗
PubMed2000

Acid-promoted reactions of ethyl linoleate with nitrite ions: formation and structural characterization of isomeric nitroalkene, nitrohydroxy, and novel 3-nitro-1,5-hexadiene and 1,5-dinitro-1, 3-pentadiene products.

The reaction of ethyl linoleate (1) with NO(2)(-) in different air-equilibrated acidic media resulted in the formation of complex patterns of products, some of which could be isolated by repeated TLC fractionation and were formulated as the nitroalkenes 2-5, the novel (1E, 5Z)-3-nitro-1,5-hexadienes 6/7, the novel (E,E)-1, 5-dinitro-1,3-pentadiene derivatives 8 and 9, and the nitro alcohols 10/11 and 12/13 by extensive GC-MS and 2D NMR analysis, as aided by 1D Hartmann-Hahn proton mapping experiments. Similar reaction of methyl oleate gave mainly nitroalkene (14/15) and allylic nitro derivatives (16/17). Formation of 2-13 may be envisaged in terms of HNO(2)-mediated nitration pathways in which regioisomeric beta-nitroalkyl radical intermediates derived from attack of NO(2) to the 1,4-pentadiene moiety of 1 evolve through competitive H-atom abstraction and free radical combination routes.

Acids↗
PubMed2000

Early physiological and cytological events induced by wounding in potato tuber.

The response of potato tuber (Solanum tuberosum L. cv. Kennebec) to mechanical wounding was investigated at different times. Changes in the levels of indole-3-acetic acid (IAA), polyunsaturated fatty acids (PUFAs) and lipid hydroperoxides (LOOHs) were monitored up to 120 min after wounding and related to the cytological events occurring up to 24 h. Twenty minutes after injury, an increase in IAA and LOOH levels and a decrease in the levels of PUFAs was observed. Wounding induced mitoses in differentiated (parenchyma) cells starting at 120 min, and promoted an increase of mitotic activity in the meristematic cells (procambium and bud dome), after 360 min. The inhibition of the increase in LOOHs and IAA by lipoxygenase (LOX) inhibitors, as well as the ability of in vitro peroxidated linoleic acid to enhance IAA production, suggest a close relationship among lipoperoxidation, IAA and mitotic activity in the response of potato tuber cells to injury, resulting in a specific growth response, i.e. bud growth and periderm formation.

Fatty Acids, Unsaturated↗
PubMed1999

Scavenging effects of terbinafine on free radicals in vitro.

One of the goals of antifungal therapy is to combine an anti-inflammatory activity with antimycotic properties, and therefore it is interesting to evaluate the capacity of active antifungal drugs to interfere with different phases of the inflammatory reaction. In order to identify a possible scavenger property of free radical species of the antifungal agent terbinafine, we studied its activity on the reduction of nitrotetrazolium blue chloride (NTB), induced by superoxide anions with the ultraviolet (UV)- and chemical-induced peroxidation of unsaturated lipid targets. NTB reduction was followed by spectrophotometer and the decomposition of squalene or methyl arachidonate by gas chromatography-mass spectrometry. Terbinafine (20 microgram and over) was capable of significantly inhibiting NTB reduction, indicating that the drug scavenges superoxide anion radicals. In these conditions no modifications of the concentration of the drug, as evaluated by high performance liquid chromatography, were observed. The UV- or chemically induced peroxidation of squalene and arachidonic acid was significantly reduced in the presence of 50 microgram of terbinafine, suggesting that the substance interferes with the chemical properties of peroxyl radicals. In all the tests used the degree of inhibition was proportional to the amount of free radicals generated. In conclusion our results indicate that terbinafine, at therapeutic concentrations, can be considered to be a free radical interceptor in vitro and could exert a mild anti-inflammatory activity in vivo.

Allylamine↗
PubMed1999

Thimerosal positivities: patch testing to methylmercury chloride in subjects sensitive to ethylmercury chloride.

The aim of this paper was to evaluate whether methylmercury chloride (MeHgCl) aq., when patch tested in a group of thimerosal-positive subjects reacting to ethylmercury chloride (EtHgCl), might be a reliable model for the better understanding of interactions between alkylmercury compounds and the skin. 19 out of 21 consecutive patients who previously had given positive patch-test reactions to both ethylmercury chloride 0.0165% eth.(EtHgCl, 0.615 mM) and MeHgCl 0.031% aq.(1.23 mM), and negative reactions to thiosalicylic acid 0.05% (3.24 mM) aq./eth. 50/50, were repatch tested to 8 microl of MeHgCl 0.031% aq. and to 8 microl of aq. solutions containing MeHgCl mixed with cysteine, glutathione, ZnSO4, MgSO4, MnSO4, ZnCl2, MgCl2 and MnCl2, respectively. The results showed that cysteine, glutathione and Zn(II) salts were able to abolish the positive reactions, demonstrating the rôle played by both thiol groups and Zn(II) itself. Patch tests concomitantly carried out in 16 out of 19 patients to 8 microl of aqueous MeHgCl and to 8 microl of aqueous solutions containing MeHgCl and MeHgCl mixed to fragment 56-61 of metallothionein I (MT I), MT I and MT II-Zn, respectively, revealed that all the MTs tested were able to reduce or to inhibit the reactions, demonstrating the effect of the thiol groups. Due to the close chemical similarities to EtHgCl and to its water solubility, MeHgCl seems to be a suitable model for evaluating the reactivity of alkylmercury compounds in the skin. We speculate that both EtHg- and MeHg-derivatives are xenobiotics with similar reactivity. However, the lack of clinical relevance of the reactions to both alkyl compounds lead us to conclude that, since environmental exposure does not seem to play a pivotal rôle, they probably have mostly to do with compounds included in in the standard series, and are elicited by reduced function of physiological SH chelators.

Adult↗
PubMed1998

Thimerosal positivities: the role of organomercury alkyl compounds.

Contact allergy to thimerosal (TH) has not been considered a marker for mercury allergy, since there is a low degree of cross-sensitivity to inorganic as well as to organic mercury salts. 40 subjects, who previously gave a positive patch test reaction only to thimerosal 0.1% pet. (Hermal), when simultaneously repatch-tested to solutions containing TH, mersalyl acid, p-amino-phenylmercuric acid, mercuric acetate and thiosalicylic acid, respectively, gave positive reactions only to TH. 36 out of 40 subjects were divided into 2 groups of 18 subjects and simultaneously repatch-tested to solutions containing TH, methylmercury chloride (MeHgCl), thiosalicylic acid, and, ethylmercury chloride (EtHgCl), respectively. EtHgCl was tested in the 1st group at 0.031% and in the 2nd group at 0.015%. The results showed that all subjects gave concomitant positive reactions to TH, EtHgCl and MeHgCl. EtHgCl 0.031% gave a higher number of reactions than EtHgCl 0.015%, underlining the rôle of the solvent in these reactions. Patch test results in 300 consecutive patients to a standard series, to which MeHgCl was added, showed that MeHgCl and TH were never able to give isolated positive reactions, and that the concomitant positive reactions occurred in only 3.6% of subjects. In conclusion, our data seem to suggest that the positive reactions to TH found in our patients were due to EtHgCl, and that the structural similarities with MeHgCl were so close that the skin reacted against each as if they were identical.

Alkylation↗
PubMed1998

Thimerosal positivities: the rôle of SH groups and divalent ions.

For a better understanding of the mechanistic details of the interactions of organomercury compounds inside the skin, 32 subjects who previously had given positive patch-test reactions to thimerosal (TH) and negative reactions to thiosalicylic acid, were divided into 2 groups. 16 subjects were repatch tested to ethylmercury chloride (EtHgCl) and to solutions containing EtHgCl mixed with L-cysteine and glutathione, respectively. The remaining 16 were repatch tested to EtHgCl and to solutions containing EtHgCl mixed with chlorides of Zn, Mg, and Mn, respectively. The results showed that whilst L-cysteine, glutathione and ZnCl2 were able to abolish or to reduce the positive reactions to EtHgCl, chlorides of Mg and Mn were unable to do so. Patch tests revealed that in causing positive reactions to TH, EtHg probably interacted with thiol groups and with Zn ions, as in biological systems when causing toxic effects. The limited number of TH reactions in the general population, the constant presence of concomitant positive reactions to EtHgCl and MeHgCl, and the lack of cross-reactivity with other organic or inorganic mercury compounds, lead us to speculate that reactions to TH are due to organomercury alkyl compounds, and that positive subjects have a constitutively reduced capability to metabolize organomercury compounds, rather than to reveal previous exposure.

Alkylmercury Compounds↗
PubMed1998

The influence exerted by cutaneous ligands in subjects reacting to nickel sulfate alone and in those reacting to more transition metals.

To study the influence exerted by cutaneous ligands in nickel reactions we have evaluated the patch tests responses to 4 aqueous nickel salts (sulfate, chloride, nitrate, acetate) able to form different complexes with different geometry. Two groups of respectively 71 subjects who previously reacted only to nickel sulfate 5% petrolatum (pet) and of 30 subjects who previously reacted to nickel sulfate 5% pet and to at least 1 other transition metal, were simultaneously repatch-tested to 200 microg of Ni++ contained in nickel sulfate in pet and to 47 microg of Ni++ contained in 4 different aqueous nickel salts. Another 2 groups of 25 subjects with the same characteristics were simultaneously repatch tested to 200 microg of Ni++ in pet and to 12 microg of aq Ni++ as in the first 2 groups. Visual score, total score, and mean value of the reactions were utilized in evaluating the degree of the responses. On testing to 200 microg of Ni++ in pet all the subjects were able to give positive responses. Whilst a higher percentage of the responses of 2+ degrees was found in subjects reacting to nickel sulfate 5% pet alone, a higher percentage of responses of 3+ degrees was observed in subjects reacting to more transition metals. On testing to 47 and 12 microg of aqueous Ni++ a large variability of responses to the single salts was observed in all the subjects. However, in subjects reacting to more metals there were either a greater number of multiple responses to 3 or 4 salts or responses stronger than those found in subjects reacting to nickel sulfate alone. Although patch testing cannot give us complete information about the degree of previous exposure, the results arising from the tests seem to demonstrate that the subjects allergic to nickel and other transition metals are more reactive than the subjects allergic only to nickel to the application of the same amounts of Ni++ contained in different salts. When considering the QSAR model, the difference in the sensitizing potential of the metal at the same penetration properties can depend on the possibility of combining with specific ligands. Therefore, it is likely that in subjects reacting to more metals there is a more uniform availability of cutaneous ligands which conditions the formation of complexes more immunogenic. The arising inflammatory reaction in these cases leads to a stronger but less specific response.

Analysis of Variance↗
PubMed1997

Increased sensitivity to peroxidative agents as a possible pathogenic factor of melanocyte damage in vitiligo.

To examine the sensitivity of vitiligo melanocytes to external oxidative stress, we studied enzymatic and non-enzymatic anti-oxidants in cultured melanocytes of normal subjects (n = 20) and melanocytes from apparently normal skin of vitiligo patients (n = 10). The activity of superoxide dismutase and catalase and the intracellular concentrations of vitamin E and ubiquinone were evaluated in cultures at the fourth or fifth passage. In addition, cells were exposed to various concentrations of a peroxidizing agent, cumene hydroperoxide (CUH, 0.66-20 microM), for 1 and 24 h. Compared to normal melanocytes, vitiligo melanocytes showed normal superoxide dismutase and significantly lower catalase activities and higher vitamin E and lower ubiquinone levels. At the concentration used, CUH did not significantly affect cell number or viability of melanocytes after either period of culture. On the contrary, vitiligo melanocytes were susceptible to the toxic effect of CUH after 24 h of continuous treatment at concentrations greater than 6.6 microM. The degree of CUH toxicity correlated strictly with the anti-oxidant pattern, defined as the ratio between vitamin E concentration and catalase activity, suggesting that the alteration in the antioxidants was the basis for sensitivity to the external oxidative stress. Our results demonstrate the presence of an imbalance in the anti-oxidant system in vitiligo melanocytes and provide further support for a free radical-mediated damage as an initial pathogenic event in melanocyte degeneration in vitiligo.

Adult↗
PubMedDate not supplied

Levels of enzymatic antioxidants activities in mononuclear cells and skin reactivity to sodium dodecyl sulphate.

Chemical irritants are able to produce several biological modifications of the skin, including the direct or indirect production of cytokines and reactive oxygen species leading to an inflammatory reaction. This report examines the existence of a possible correlation between the skin sensitivity to the irritant sodium dodecyl sulphate (SDS) and the activity of the enzymatic antioxidants. In twenty-three healthy subjects the evaluation of the epidermal and peripheral blood mononuclear cells (PBMCs) activities of Superoxide Dismutase (SOD) and Catalase (Cat) demonstrate a significant correlation (r= 0,85 and p< 0,005 for SOD, and r= 0,87 and p< 0,0001 for Cat). Based on this result, on a further group of normal subjects (n=13) we studied the link between the threshold dose of skin reactivity to SDS and the activities of the enzymatic antioxidants in PBMCs. The degree of skin modification induced by SDS, applied at different concentrations for 24 hrs, was determined by means of Trans Epidermal Water Loss (TEWL), Erythemal Index or by Visual Score (VS). The minimal dose of the irritant capable of inducing skin modifications, was significantly correlated with SOD (r=0,77) and Cat (r=0,81) activities in PBMCs, and the modification of TEWL or EI were inversely correlated with levels of antioxidants in PBMCs (r=-0,62 for SOD and r=-0,66 for Cat). Our results indicate that the skin reactivity to irritants can be modulated by the levels of antioxidants, and suggest a possible therapeutical approach in preventing irritant contact dermatitis.

Adult↗
PubMedDate not supplied

Direct chiral resolution of tiaprofenic acid in pharmaceutical formulations by capillary zone electrophoresis using cyclodextrins as chiral selector.

Capillary zone electrophoresis (CZE) was used for the enantiomeric separation of (R,S)-tiaprofenic acid ([R,S]-Tia) in a pharmaceutical formulation employing an acetate buffer at pH 4.5 and 2,3,6-tri-O-methyl-beta-cyclodextrin (tri-OMe-beta-CD) as the chiral selector. The effect of the concentration of trimethylated-beta-cyclodextrin in the presence of carboxymethylated-beta-cyclodextrin (CM-beta-CD) on enantiomeric resolution of (R,S)-Tia and (R,S)-5-benzoyl-alpha-methyl-3-thiopheneacetic acid (3-isomer of tiaprofenic acid, 3-Tia) was investigated at pH 4, 4.5, and 5.

Chemistry, Pharmaceutical↗