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ABSTRACT: A hydrophilic interaction chromatography-based method, in combination with 1.7 microm ethylene bridged hybrid particle packed column (100 mm x 2.1 mm I.D.) and ultraperformance liquid chromatography, has been developed to measure cytosine (C) and methylcytosine (mC) in order to evaluate the extent of DNA methylation. Separation of cytosine and methylcytosine was achieved with good resolution and in fairly short times (5.5 min) by using isocratic elution with a mixture of 97:3 (v/v) acetonitrile/10 mM ammonium acetate as a mobile phase. The determination coefficients of C and mC were high (R(2) > 0.999) within the range tested. The %RSD for intraday and interday were respectively 2.2% and 2.5% for C and 3.5% and 3.8% for mC. The limit of detection was 0.52 microM (0.52 fmol on-column) both for C and mC while the limit of quantification was 1.72 microM (1.72 fmol on-column) both for C and mC. The smallest amount of purified DNA that yielded a measurable level of C and mC was 10 microg. On the whole, this method is simple, rapid, sensitive, and precise.
Analytical and Bioanalytical Chemistry 03/2010; 396(8):2937-41. · 3.78 Impact Factor
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ABSTRACT: High intake of natural antioxidants (NA) from plant-derived foods and beverages is thought to provide cardiovascular benefits. The endothelium plays a pivotal role in cardiovascular homeostasis, and for this reason, the molecular events resulting from NA actions on endothelial cells (ECs) are actively investigated. Here, we show the direct impact of two NA, coumaric acid and resveratrol, on intracellular reactive oxygen species levels, protein carbonylation, and cell physiology in human ECs. While at lower doses, both NA promoted antioxidant effects, at moderately high doses, NA elicited a dose-dependent pro-oxidant effect, which was followed by apoptosis, cell damage, and phospho-Akt downregulation. NA-induced pro-oxidant effects were counteracted by N-acetyl cysteine and diphenyleneiodonium (DPI), suggesting a role for flavin oxidases in NA-induced toxicity. DPI also prevented NA-induced phospho-Akt downregulation indicating that Akt can work downstream of flavin oxidases in mediating cellular responses to NA. Stimulation of phospho-Akt by insulin dramatically counteracted NA-induced cell death, an effect abolished by Akt inhibition further suggesting that mechanistically Akt regulates cell survival in response to NA-induced stress. Although further studies are required to better characterize the molecular mechanism of NA-induced cell toxicity, our study is the first to show in a human vascular model that moderately high doses of NA can induce cell damage mediated by flavoproteins and the Akt pathway.
Toxicological Sciences 12/2009; 114(1):101-12. · 4.65 Impact Factor
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Angelo Zinellu,
Antonio Lepedda Jr,
Salvatore Sotgia,
Elisabetta Zinellu,
Giommaria Marongiu,
Maria Franca Usai, Leonardo Gaspa,
Pierina De Muro,
Marilena Formato,
Luca Deiana,
Ciriaco Carru
[show abstract]
[hide abstract]
ABSTRACT: We describe a new method for the quantification of low molecular weight thiols, as homocysteine, cysteine, cysteinylglycine, glutamylcysteine and glutathione bound to human plasma albumin. After albumin isolation and purification by SDS-PAGE, thiols were freed from protein with tri-n-butylphosphine and successively derivatized with 5-iodoacetamidofluorescein. Samples were then injected and quantified in about 18 min by CE with laser induced fluorescence detection. Precision tests indicate a good repeatability of the method both for migration times (RSD<0.63%) and areas (RSD<2.98%). The method allows to measure all five low molecular weight thiols released from just 3 μg of albumin thus improving the other described methods in which only three or four thiols were detected. Due to the elevated sensitivity (LOD of 0.3 pM for all thiols), also low molecular weight thiols bound to albumin filtered in tissues could be quantified.
Journal of Separation Science 11/2009; 33(1):126 - 131. · 2.73 Impact Factor
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Angelo Zinellu,
Antonio Lepedda,
Salvatore Sotgia,
Elisabetta Zinellu,
Giommaria Marongiu,
Maria Franca Usai, Leonardo Gaspa,
Pierina De Muro,
Marilena Formato,
Luca Deiana,
Ciriaco Carru
[show abstract]
[hide abstract]
ABSTRACT: We describe a new method for the quantification of low molecular weight thiols, as homocysteine, cysteine, cysteinylglycine, glutamylcysteine and glutathione bound to human plasma albumin. After albumin isolation and purification by SDS-PAGE, thiols were freed from protein with tri-n-butylphosphine and successively derivatized with 5-iodoacetamidofluorescein. Samples were then injected and quantified in about 18 min by CE with laser induced fluorescence detection. Precision tests indicate a good repeatability of the method both for migration times (RSD<0.63%) and areas (RSD<2.98%). The method allows to measure all five low molecular weight thiols released from just 3 microg of albumin thus improving the other described methods in which only three or four thiols were detected. Due to the elevated sensitivity (LOD of 0.3 pM for all thiols), also low molecular weight thiols bound to albumin filtered in tissues could be quantified.
Journal of Separation Science 11/2009; 33(1):126-31. · 2.73 Impact Factor
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[show abstract]
[hide abstract]
ABSTRACT: A rapid and simple short-end injection capillary zone electrophoresis method was developed for the quantification of plasma uric acid. The separation was performed in an uncoated fused-silica capillary (50 microm ID, 60 cm total length, 10.2 cm effective length) by using as a background electrolyte a 75 mmol/L glycylglycine solution titrated with NaOH 5 mol/L to pH 9.0, a voltage of 28 kV, a cartridge temperature of 15 degrees C, and direct UV detection at 292 nm. Under optimized conditions, uric acid was determinate in little more than 1 min (1.076 minutes). In order to verify the accuracy of the analysis, urate levels were measured in 543 apparently healthy volunteers by the new assay and our previous method, and the obtained data were compared by Passing-Bablock regression, Bland-Altman test, and a new regression-based approach, which showed a good agreement between two methods.
Analytical and Bioanalytical Chemistry 10/2009; 395(8):2577-82. · 3.78 Impact Factor
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Amino Acids 02/2009; 36(1):159. · 3.25 Impact Factor
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ABSTRACT: We investigated the levels of the endogenous nitric oxide synthase inhibitor asymmetric dimethylarginine (ADMA), as well as homocysteine and cysteine thiols, in a cohort of subjects affected by retinal vein occlusion (RVO) disease.
Capillary electrophoresis analysis was performed in both RVO subjects (n=54) and in a control group (n=32).
No differences were found between controls and patients; however, after categorisation for RVO type, central RVO (CRVO) patients showed higher levels of ADMA (0.710+/-0.139 micromol/L) than controls (0.635+/-0.117 micromol/L) and branch RVO patients (0.642+/-0.096 micromol/L). Moreover, cysteine plasma levels were also significantly higher in CRVO patients than in controls (265.8+/-46.9 vs. 226.7+/-51.9 micromol/L, p<0.01), while homocysteine plasma concentration was more or less identical in all groups.
We hypothesise that the elevated levels of cysteine in CRVO patients may post-translationally inhibit dimethylarginine dimethylaminohydrolase enzyme activity, as already described for homocysteine, thus contributing to the accumulation of ADMA in this patient group.
Clinical Chemistry and Laboratory Medicine 02/2008; 46(3):387-92. · 2.15 Impact Factor
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ABSTRACT: In this work we describe a new method for taurine quantification in plasma by capillary electrophoresis laser-induced fluorescence detection. Taurine is derivatized with fluorescein isothiocyanate at 100 degrees C in 20 min. These conditions allow to reduce the pre-analytical times and to derivatize quantitatively the taurine contained in the reaction mixture, contrary to the room temperature derivatization commonly adopted. FITC-taurine adduct is analyzed in an uncoated fused-silica capillary, 75 mum ID and 40 cm effective length using a 20 mmol/L tribasic sodium phosphate buffer pH 11.8, at 22 kV. To avoid the typical problems due to instability of FITC-adduct, we use the homocysteic acid as internal standard. The loss of FITC-taurine signal during the sequence analysis is compensated by the same loss of FITC-internal standard adduct, thus giving a noteworthy improvement in the assay precision. The method shows a good reproducibility of the migration times (coefficient of variation, CV%, 1.93) and the peak areas (CV%, 3.65). Intra- and interassay CV were 4.63 and 6.44%, respectively, and analytical recovery was between 98.1 and 102.3%. Assay application was tested measuring taurine plasma levels in 50 healthy volunteers in which a mean value of 60.2 +/- 17.9 micromol/L was found. Moreover, the applicability of the method was also checked on energy drinks and milk.
Amino Acids 02/2008; 36(1):35-41. · 3.25 Impact Factor
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Angelo Zinellu,
Salvatore Sotgia,
Anna Maria Posadino,
Valeria Pasciu,
Elisabetta Zinellu,
Maria Franca Usai,
Bastianina Scanu,
Roberto Chessa, Leonardo Gaspa,
Bruna Tadolini,
Luca Deiana,
Ciriaco Carru
[show abstract]
[hide abstract]
ABSTRACT: Protein modification due to S-glutathio(ny)lation, usually a reversible process in intact cells, arises interest as a possible mode of regulatory events that may potentially modify a large number of cellular processes. However, since less than 1% of the total protein is S-thiolated in resting cells, high sensitivity methods are required for its evaluation. We set up a new method by CE with LIF detection that allows to measure all forms of intracellular GSH involved in the process. For total and reduced glutathione, cell lysates were rapidly derivatized by 5-iodoacetoamidofluorescein (5-IAF), a selective reagent which traps thiol groups, thus minimizing auto-oxidation. Derivatized samples were separated in a 47 cmx75 microm id capillary by using 7 mmol/L sodium phosphate at pH 11.6. For the evaluation of S-glutathio(ny)lation, intracellular proteins from cell lysates were precipitated and washed to eliminate free GSH. After protein resuspension with NaOH and reduction treatment with tri-n-butylphosphine (TBP), the freed GSH was dried in a vacuum concentrator and directly dissolved in the derivatization mixture. GSH-IAF adduct was detected in a 6 mmol/L sodium phosphate, 3 mmol/L boric acid, and 75 mmol/L N-methylglucamine run buffer in less than 5 min. The high sensitivity ensured by 5-IAF use and sample concentration, allowed to quantify GSH at levels as low as 5 nmol/L, value suitable for the evaluation of protein S-glutathio(ny)lation. The method suitability was checked both in HUVEC and ECV304 cultured cells.
Electrophoresis 10/2007; 28(18):3277-83. · 3.30 Impact Factor
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[show abstract]
[hide abstract]
ABSTRACT: The short term (up to 14 days after restoration) release of selected ions (i.e., Hg(2+), Cu(2+) and Zn(2+)) from Dispersalloy into artificial saliva has been evaluated in regards to the nature of the saliva (Fusayama and McCarty and Shklar's solutions), the amount of amalgam, the time of contact and the periodical renewal (every 48 h interval) of artificial saliva. The evaluation of the ionic fraction of such metals has been accomplished by using anodic stripping methods (i.e., Differential Pulse Anodic Stripping Voltammetry, DPASV) with a 7 microm graphite disk microelectrode as a working electrode. Data obtained in this work are almost unprecedented in the literature due the fact that such analytical method exclude metals in non-ionic forms (e.g., metals or organometallic compounds). The high concentrations measured in every experimental condition confirm the concern for the short-term release of metals from amalgam into saliva.
Journal of Materials Science Materials in Medicine 09/2007; 18(8):1521-7. · 2.32 Impact Factor
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[show abstract]
[hide abstract]
ABSTRACT: Experimental studies document that increased asymmetric dimethylarginine (ADMA) blood levels inhibit NOS significantly, reducing NO generation. ADMA measurement often needs sample cleanup by SPE prior to chromatography and precolumn derivatization that cannot be easily employed in a routine clinical setting. We set up a new reliable CE method to measure ADMA, symmetric dimethylarginine (SDMA), and arginine without sample extraction or precolumn derivatization in order to examine their concentrations in human plasma. Sample was concentrated prior to CE injection and analytes were monitored by UV detection. CE analysis was performed in an uncoated fused-silica capillary, 75 microm id and 60.2 cm length (50 cm to the detection window), injecting 1 s water plug (0.5 psi) followed by 10 s of the sample (0.5 psi). Separation was carried out in a 50 mmol/L Tris-phosphate run buffer at pH 2.30, 15 degrees C and 15 kV (75 microA) at normal polarity. Recovery of plasma ADMA was 101-104% and inter-day CV was less than 3%. Assay performance was evaluated measuring the levels of arginine and its dimethyl derivatives in 77 subjects. Passing-Bablok regression and Bland-Altman test for methods comparison suggest that the data obtained by our method and by a reference CE-LIF assay are similar.
Electrophoresis 07/2007; 28(12):1942-8. · 3.30 Impact Factor
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Angelo Zinellu,
Salvatore Sotgia,
Maria Franca Usai,
Elisabetta Zinellu,
Anna Maria Posadino, Leonardo Gaspa,
Roberto Chessa,
Antonio Pinna,
Francesco Carta,
Luca Deiana,
Ciriaco Carru
[show abstract]
[hide abstract]
ABSTRACT: Methionine is an important amino acid involved in protein synthesis and transmethylation reactions. It is also the precursor of homocysteine and cysteine, two important risk factors for cardiovascular diseases. As homocysteine research has gained impulsion, the evaluation of plasma methionine concentrations has acquired importance. Methionine measurement generally has been performed by HPLC after o-phthalaldehyde derivatization. Its separation from other amino acids is time-consuming. We set up a new specific capillary electrophoresis method in which analyte derivatization was avoided by sample concentration before analysis. Methionine was detected by UV absorbance at 204 nm with a detection limit of 0.5 micromol/L. By a capillary with an effective length of 50 cm filled with 125 mmol/L Tris phosphate buffer at pH 2.3, the separation occurred in less than 14 min. Precision tests indicated a good test repeatability for both migration times (coefficient of variation [CV]<0.3%) and areas (CV<2.0%). Moreover, a good reproducibility of intraassay and interassay tests was obtained (CV<2.9% and CV<3.5%, respectively). The Passing-Bablok regression and the Bland-Altman test for methods comparison suggest that the data obtained by our method and by a reference HPLC assay are similar. Assay performance was evaluated measuring methionine concentrations in retinal venous occlusive disease.
Analytical Biochemistry 04/2007; 363(1):91-6. · 3.00 Impact Factor
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[show abstract]
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ABSTRACT: Angiotensin converting enzyme (ACE) inhibition exerts positive effects on the microvasculature of normotensive animals, although this concept is not universally accepted. Recently, ACE inhibitors have been suggested to be useful for rescue in peripheral ischemia.
We investigated whether chronic treatment with the ACE inhibitor ramipril may have a positive impact on the defective healing response to ischemia that is typical of spontaneously hypertensive rats (SHR). Unilateral limb ischemia was induced in 20-week-old SHR by surgically removing the left femoral artery. Rats were allowed to regain consciousness and then were randomly allocated to treatment with ramipril (1 mg/kg body weight in drinking water) or vehicle for 28 days.
The SHR failed to develop reparative angiogenesis in response to ischemia, thus having inadequate perfusion recovery. Ramipril reduced both tail-cuff systolic blood pressure (180 +/- 7 v 207 +/- 2 mm Hg in the vehicle group at 28 days, P < .05) and intra-arterial mean blood pressure (115 +/- 6 v 135 +/- 5 mm Hg in the vehicle group, P < .05). These effects were associated with increased responsiveness to endothelium-dependent vasodilatation by acetylcholine. Treatment with ramipril did not influence muscular capillary and arteriole density but accelerated the rate of perfusion recovery, leading to complete healing within 28 days after surgery.
These results indicate that ACE inhibition by ramipril may be useful for the treatment of peripheral vascular complications in hypertension.
American Journal of Hypertension 05/2002; 15(5):410-5. · 3.18 Impact Factor
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Costanza Emanueli,
Maria Bonaria Salis,
Tiziana Stacca,
Gianfranco Pintus,
Rudolf Kirchmair,
Jeffrey M Isner,
Alessandra Pinna, Leonardo Gaspa,
Domenico Regoli,
Cecile Cayla,
João B Pesquero,
Michael Bader,
Paolo Madeddu
[show abstract]
[hide abstract]
ABSTRACT: Kinins are modulators of cardiovascular function. After ischemic injury, enhanced kinin generation may contribute in processes responsible for tissue healing.
Using pharmacological and genetic approaches, we investigated the role of kinin B(1) receptor in reparative angiogenesis in a murine model of limb ischemia. The effect of B(1) pharmacological manipulation on human endothelial cell proliferation and apoptosis was also studied in vitro. Abrogation of B(1) signaling dramatically inhibited the native angiogenic response to ischemia, severely compromising blood perfusion recovery. Outcome was especially impaired in B(1) knockouts that showed a very high incidence of limb necrosis, eventually leading to spontaneous auto-amputation. Conversely, local delivery of a long-acting B(1) receptor agonist enhanced collateral vascular growth in ischemic skeletal muscle, accelerated the rate of perfusion recovery, and improved limb salvage. In vitro, B(1) activation stimulated endothelial cell proliferation and survival, whereas B(1) antagonism induced apoptosis.
Our results indicate that the B(1) plays an essential role in the host defense response to ischemic injury. B(1) signaling potentiation might be envisaged as a utilitarian target for the treatment of ischemic vascular disease.
Circulation 02/2002; 105(3):360-6. · 14.74 Impact Factor
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ABSTRACT: 1. The concept that angiotensin II exerts pro-angiogenic activity is not universally accepted. We evaluated whether inhibition of the renin-angiotensin system (RAS) would influence reparative angiogenesis in a murine model of limb ischaemia. 2. Perfusion recovery following surgical removal of the left femoral artery was analysed by laser Doppler flowmetry in mice given the ACE inhibitor ramipril (1 mg kg(-1) per day), the AT(1) antagonist losartan (15 mg kg(-1) per day), or vehicle. Muscular capillarity was examined at necroscopy. Ramipril-induced effects were also studied under combined blockade of kinin B(1) and B(2) receptors. Furthermore, the effects of ischaemia on AT(1) gene expression and ACE activity were determined. 3. In untreated mice, muscular AT(1a) gene expression was transiently decreased early after induction of limb ischaemia, whereas AT(1b) mRNA was up-regulated. ACE activity was reduced in ischaemic muscles at 1 and 3 days. Gene expression of AT(1) isoforms as well as ACE activity returned to basal values by day 14. Spontaneous neovascularization allowed for complete perfusion recovery of the ischaemic limb after 21 days. 4. Reparative angiogenesis was negatively influenced by either ramipril (P<0.02) or losartan (P<0.01), leading to delayed and impaired post-ischaemic recovery (50 - 70% less compared with controls). Ramipril-induced effects remained unaltered under kinin receptor blockade. 5. The present study indicates that (a) expression of angiotensin II AT(1) receptors and ACE activity are modulated by ischaemia, (b) ACE-inhibition or AT(1) antagonism impairs reparative angiogenesis, and (c) intact AT(1) receptor signalling is essential for post-ischaemic recovery. These results provide new insights into the role of the RAS in vascular biology and suggest cautionary use of ACE inhibitors and AT(1) antagonists in patients at risk for developing peripheral ischaemia.
British Journal of Pharmacology 01/2002; 135(1):87-92. · 4.41 Impact Factor
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[show abstract]
[hide abstract]
ABSTRACT: The concept that angiotensin II exerts pro-angiogenic activity is not universally accepted. We evaluated whether inhibition of the renin-angiotensin system (RAS) would influence reparative angiogenesis in a murine model of limb ischaemia.Perfusion recovery following surgical removal of the left femoral artery was analysed by laser Doppler flowmetry in mice given the ACE inhibitor ramipril (1 mg kg−1 per day), the AT1 antagonist losartan (15 mg kg−1 per day), or vehicle. Muscular capillarity was examined at necroscopy. Ramipril-induced effects were also studied under combined blockade of kinin B1 and B2 receptors. Furthermore, the effects of ischaemia on AT1 gene expression and ACE activity were determined.In untreated mice, muscular AT1a gene expression was transiently decreased early after induction of limb ischaemia, whereas AT1b mRNA was up-regulated. ACE activity was reduced in ischaemic muscles at 1 and 3 days. Gene expression of AT1 isoforms as well as ACE activity returned to basal values by day 14. Spontaneous neovascularization allowed for complete perfusion recovery of the ischaemic limb after 21 days.Reparative angiogenesis was negatively influenced by either ramipril (P<0.02) or losartan (P<0.01), leading to delayed and impaired post-ischaemic recovery (50 – 70% less compared with controls). Ramipril-induced effects remained unaltered under kinin receptor blockade.The present study indicates that (a) expression of angiotensin II AT1 receptors and ACE activity are modulated by ischaemia, (b) ACE-inhibition or AT1 antagonism impairs reparative angiogenesis, and (c) intact AT1 receptor signalling is essential for post-ischaemic recovery. These results provide new insights into the role of the RAS in vascular biology and suggest cautionary use of ACE inhibitors and AT1 antagonists in patients at risk for developing peripheral ischaemia.British Journal of Pharmacology (2002) 135, 87–92; doi:10.1038/sj.bjp.0704461
British Journal of Pharmacology 12/2001; 135(1):87 - 92. · 4.41 Impact Factor
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ABSTRACT: The binding of bradykinin (BK) to its B2 receptor results in a wide spectrum of biological effects including vasodilation, smooth muscle contraction and relaxation, pain, and inflammation. In order to gain a better insight into the physiological function of this potent vasoactive peptide, murine models have been created by the use of gene insertion or deletion. The results of studies using these strategies are revisited in the present article. In transgenic mice harboring the human BK B2 receptor cDNA (cHBKR), expression of the transgene was identified in the aorta, brain, heart, lung, liver, kidney, uterus and prostate gland by RT-PCR Southern blot analysis. These mice displayed an exaggerated hypotensive response to intra-aortic injection of BK, whereas the blood pressure of knockout mice, homozygous for targeted disruption of the endogenous gene, was insensitive to BK. Two transgenic mouse lines expressing the human BK B2 receptor showed a significant reduction of systolic tail-cuff blood pressure (84±1 mm Hg, n=28; 80±1 mm Hg, n=24; P<0.001) compared with the control littermates (97±1 mm Hg, n=52). Systolic blood pressure was elevated in BK B2 receptor knockout mice (124±1 mm Hg, n=38). In heterozygous mice, systolic blood pressure was similar to that of controls until 5 month-old, then it raised to the elevated levels of knockout mice at 7 months of age. Together these data indicate that kinins acting through the B2 receptor play a role in the development of the blood pressure phenotype.
Immunopharmacology 10/1999;
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[show abstract]
[hide abstract]
ABSTRACT: We evaluated whether kinins exert a protective action against the development of two-kidney, one clip (2K1C)
hypertension, a model characterized by an activated renin-angiotensin system in the ischemic kidney and increased
expression of the bradykinin (BK) B<sub>2</sub> receptor in the contralateral kidney. BK B<sub>2</sub>-receptor knockout (B<sub>2</sub>
-/-), wild-type
(B<sub>2</sub>
+/+), and heterozygous (B<sub>2</sub>
+/-) mice underwent clipping of the left renal artery, with the other kidney remaining
untouched. Basal systolic blood pressure (SBP, via tail-cuff plethysmography) was higher in B<sub>2</sub>
-/-mice than in B<sub>2</sub>
+/-
or B<sub>2</sub>
+/+ mice (121±2 versus 113±2 and 109±1 mm Hg; P <0.05 for both comparisons). SBP did not change from basal
values after sham operation, but it increased in mice that underwent clipping. The increase in SBP was greater in 2K1C
B<sub>2</sub>
-/- mice than in B<sub>2</sub>
+/- or B<sub>2</sub>
+/+ mice (28±2 versus 14±2 and 14±2 mm Hg, respectively, at 2 weeks; P <0.05 for both
comparisons). Blockade of the BK B<sub>2</sub> receptor by Icatibant enhanced the pressure response to clipping in B<sub>2</sub>
+/+ mice
(29±2 mm Hg at 2 weeks). Intra-arterial mean blood pressure (MBP) was higher in 2K1C than in respective
sham-operated mice, with the MBP difference being higher in B<sub>2</sub>
-/- mice (32 and 38 mm Hg, at 2 and 4 weeks,
respectively), and higher in B<sub>2</sub>
+/+ mice given Icatibant (30 and 32 mm Hg) than in B<sub>2</sub>
+/+ mice without Icatibant (17 and
18 mm Hg). At 4 weeks, acute injection of an angiotensin type 1 receptor antagonist normalized the MBP of 2K1C
hypertensive mice. A tachycardic response was observed 1 week after clipping in B<sub>2</sub>
-/- and B<sub>2</sub>
+/- mice, but this effect
was delayed in B<sub>2</sub>
+/+ mice. However, the HR response to clipping in B<sub>2</sub>
+/+ mice was enhanced by Icatibant. Within each
strain, heart weight to body weight ratio was greater in 2K1C hypertensive mice than in sham-operated control animals
(B<sub>2</sub>
-/-: 5.7±0.1 versus 5.2±0.1; B<sub>2</sub>
+/+: 5.1±0.1 versus 4.5±0.1; P <0.01 for both comparisons). The clipped kidney
weight to nonclipped kidney weight ratio was consistently reduced in mice with 2K1C hypertension. Our results indicate
that kinins acting on the BK B<sub>2</sub> receptor exert a protective action against excessive blood pressure elevation during early
phases of 2K1C hypertension.
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[hide abstract]
ABSTRACT: A comparison between two ion selective electrode (ISE) potentiometric
methods is reported for determining the amount of fluoride in hard dental tissue after
placement of fluoride-releasing dental restorations. The two methods are: (1) the
direct method involving linear calibration (LC), and (2) a spiking method involving
multiple standard additions (MA). Results showed that measurements performed by
the LC method underestimate the amount of fluoride released by up to 30%.
Recovery tests demonstrated that the use of MA and blank correction procedures is
useful for an accurate and sensitive ISE determination of fluoride in hard dental
tissues.
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[show abstract]
[hide abstract]
ABSTRACT: The short term (up to 14 days after restoration) release of selected ions (i.e., Hg<sup>2+</sup>, Cu<sup>2+</sup> and Zn<sup>2+</sup>) from Dispersalloy® into artificial saliva has been evaluated in regards to the nature of the saliva (Fusayama and McCarty and Shklar’s solutions), the amount of amalgam, the time of contact and the periodical renewal (every 48 h interval) of artificial saliva. The evaluation of the ionic fraction of such metals has been accomplished by using anodic stripping methods (i.e., Differential Pulse Anodic Stripping Voltammetry, DPASV) with a 7 μm graphite disk microelectrode as a working electrode. Data obtained in this work are almost unprecedented in the literature due the fact that such analytical method exclude metals in non-ionic forms (e.g., metals or organometallic compounds). The high concentrations measured in every experimental condition confirm the concern for the short-term release of metals from amalgam into saliva.
