Victor Petrov - Academia.edu (original) (raw)
Papers by Victor Petrov
We derive a new non-abelian Stokes theorem by rewriting the Wilson loop as a gauge-invariant area... more We derive a new non-abelian Stokes theorem by rewriting the Wilson loop as a gauge-invariant area integral, at the price of integrating over an auxiliary field from the coset SU(N) / [U(1)]^{N-1} space. We then introduce the relativistic quark--monopole interaction as a Wess--Zumino-type action, and extend it to the non-abelian case. We show that condensation of monopoles and confinement can be investigated in terms of the behaviour of the monopole world lines. One can thus avoid hard problems of how to introduce monopole fields and dual Yang--Mills potentials.
European Physical Journal A, 1997
We predict an exotic Z + baryon (having spin 1/2, isospin 0 and strangeness +1) with a relatively... more We predict an exotic Z + baryon (having spin 1/2, isospin 0 and strangeness +1) with a relatively low mass of about 1530 M eV and total width of less than 15 M eV . It seems that this region of masses has avoided thorough searches in the past.
In the limit of large number of colors N the nucleon consisting of N quarks is heavy, and one can... more In the limit of large number of colors N the nucleon consisting of N quarks is heavy, and one can treat it semiclassically, like the large-Z Thomas--Fermi atom. The role of the semiclassical field binding the quarks in the nucleon is played by the pion or chiral field; its saddle-point distribution inside the nucleon is called the chiral soliton. The old Skyrme model for this soliton is an over-simplification. One can do far better by exploiting a realistic and theoretically-motivated effective chiral lagrangian presented in this paper. As a result one gets not only the static characteristics of the nucleon in a fair accordance with the experiment (such as masses, magnetic moments and formfactors) but also much more detailed dynamic characteristics like numerous parton distributions. We review the foundations of the Chiral Quark-Soliton Model of the nucleon as well as its recent applications to parton distributions, including the recently introduced `skewed' distributions, and to the nucleon wave function on the light cone.
Physical Review D, 2004
We calculate exactly functional determinants for quantum oscillations about periodic instantons w... more We calculate exactly functional determinants for quantum oscillations about periodic instantons with non-trivial value of the Polyakov line at spatial infinity. Hence, we find the weight or the probability with which calorons with non-trivial holonomy occur in the Yang--Mills partition function. The weight depends on the value of the holonomy, the temperature, Lambda_QCD, and the separation between the BPS monopoles (or dyons) which constitute the periodic instanton. At large separation between constituent dyons, the quantum measure factorizes into a product of individual dyon measures, times a definite interaction energy. We present an argument that at temperatures below a critical one related to Lambda_QCD, trivial holonomy is unstable, and that calorons ``ionize'' into separate dyons.
Journal of Experimental and Theoretical Physics, 2000
We perform the dual transformation of theYang-Mills theory in three dimensions using the Wilson a... more We perform the dual transformation of theYang-Mills theory in three dimensions using the Wilson action on the cubic lattice. The dual lattice is made of tetrahedra triangulating a 3-dimensional curved manifold but which is embedded into a flat 6-dimensional space [for the SU(2) gauge group]. In the continuum limit, the theory can be reformulated in terms of 6-component gauge-invariant scalar fields having the meaning of the external coordinates of the dual lattice sites. These 6-component fields induce a metric and a curvature of the 3-dimensional dual-color space. The Yang-Mills theory can also be rewritten as a quantum gravity theory with the Einstein-Hilbert action but with a purely imaginary Newton constant plus a homogeneous “ether” term. The theory can be formulated in a gauge-invariant and local form without explicit color degrees of freedom.
Physical Review D, 2004
We analyze what consequences has the observation of exotic pentaquark baryons on the location of ... more We analyze what consequences has the observation of exotic pentaquark baryons on the location of the non-exotic baryons belonging to the antidecuplet. We suggest that there must be a new nucleon state at 1650-1690 MeV and a new Sigma baryon at 1760-1810 MeV.
American Journal of Hypertension, 1998
To evaluate the role of intracellular calcium and particularly Ca 2؉ uptake in the initiation of ... more To evaluate the role of intracellular calcium and particularly Ca 2؉ uptake in the initiation of lymphocyte mitogenesis, the effect of mibefradilwhich blocks both L-and T-type calcium channels with a more selective blockade of T-type channels-on the proliferation of human peripheral blood mononuclear cells (PBMC) is compared with the effect of nifedipine, which blocks only the L-type calcium channel. The rate of 3 H-thymidine, 3 H-uridine, and 3 H-leucine incorporation into control and concanavalin Astimulated PBMC in the presence or absence of the calcium channel blockers mibefradil or nifedipine (1, 10, or 50 mol/L), and of the intracellular calcium antagonist TMB-8 or the calmodulin antagonist W-7 (1, 10, 25, or 50 mol/L) was assayed in cells cultured for 3 days. The cellular cytotoxicity and the cell number in growing cultures was also determined in mibefradil-or nifedipine-treated control or stimulated cells. Mibefradil and nifedipine reduced the cell number and the 3 H-thymidine, 3 H-uridine, or 3 H-leucine incorporation or the de novo DNA, RNA, or protein synthesis in control and concanavalin Astimulated human PBMC in a concentrationdependent manner. Mibefradil exhibited a more pronounced inhibition than nifedipine. The inhibitory effect of mibefradil or nifedipine on DNA synthesis was dependent upon the timing of treatment with the drugs. The inhibitory effect of mibefradil or nifedipine on the lymphoproliferative response was nearly abolished if the drugs were added 20 h after cell stimulation. A markedly reduced inhibitory effect was found when mibefradil or nifedipine were added 1 to 7 h after cell stimulation. However, regardless of time of addition, TMB-8 and W-7 caused a persistent inhibition of the proliferation of human PBMC. Our data show that mibefradil had a more pronounced inhibitory effect on the proliferation of human PBMC than nifedipine and that this inhibitory effect on de novo DNA synthesis was dependent upon the timing of treatment with both drugs. Mibefradil and nifedipine also reduce RNA and protein synthesis in human PBMC. Therefore, administration of these calcium channel blockers to inhibit cellular proliferation might be most beneficial at anatomic sites where cellular proliferation is not already an active process, while being ineffective in the presence of ongoing active proliferation, as suggested by some prospective studies. Am
American Journal of Hypertension, 1999
A double blind, placebo-controlled, parallel study was conducted on the effect of a high daily or... more A double blind, placebo-controlled, parallel study was conducted on the effect of a high daily oral calcium supplementation of 1 g elemental calcium, given twice daily for 16 weeks in normal male subjects, on plasma renin, aldosterone, kallikrein, cGMP, cAMP, and calciotropic hormones, intracellular calcium concentrations, and plasma total and ionized calcium. After a 1-month run-in period on a limited use of dairy products, the subjects (n ؍ 32) were allocated to a placebo or a calcium group. Placebo or 1 g elemental calcium was administered twice daily in the morning and evening for 16 weeks. All subjects were investigated at baseline and after 1, 2, 4, 8, and 16 weeks of placebo or calcium administration.
American Journal of Hypertension, 2000
To investigate whether the aminopeptidase B and leucine aminopeptidase inhibitor bestatin, the ch... more To investigate whether the aminopeptidase B and leucine aminopeptidase inhibitor bestatin, the chymase inhibitor chymostatin, the calpain inhibitor E-64 and the neub-al sedne protease inhibitor leupeptin affect the angiotensin converting enzyme (ACE) activity in T-lymphecytes. ACE-activity in homogenates of T-lymphecytes or in intact T-lymphocytes in suspension was measured by determing fluonmetncally histidyl-leucine, formed from the conversion of hippurylhistidyl-leucine, coupled with o-phtaldialdehyde. The effect of various concentrations (10-~ -10 .3 M) of the angiotensin-converting enzyme inhibitors lisinopril and captopdl and of the venous protease inhibitors on ACE-activity was studied. Lisinopril and captopnl concentration-dependently reduce the ACEactivity in homogenates of T-lymphocytes. Lisinopdl exhibit a more pronounced inhibition of ACE in T-tymphocytes than captopdl. Chymostatin and E-64 have no effect on the ACE-activity in
Journal of Hypertension, 1995
A double-blind, placebo-controlled parallel-group study was conducted on the effect of a high lev... more A double-blind, placebo-controlled parallel-group study was conducted on the effect of a high level of daily oral calcium supplementation (1 g elemental calcium given twice a day for 16 weeks) in normal male subjects on blood pressure, intracellular cationic concentrations and transmembrane cation transport systems, plasma total and ionized calcium, and calciotropic hormones. After a 1-month run-in period with a limited intake of dairy products, the 32 subjects were allocated to a placebo or a calcium group. Placebo or 1 g elemental calcium was administered twice a day, in the morning and evening, for 16 weeks. All subjects were investigated at baseline and after 1, 2, 4, 8 and 16 weeks of placebo or calcium administration. Compared with the placebo group, standing systolic blood pressure was decreased in the calcium group, whereas the standing diastolic blood pressure tended to decrease. The changes in supine systolic and diastolic blood pressure did not differ between the placebo and calcium groups. Decreased intra-erythrocyte and intraplatelet sodium and calcium concentrations, an increased activity of platelet and erythrocyte sodium-pump activity and a reduced membrane cholesterol content were observed in the calcium-treated subjects. Erythrocyte membrane surface and core microviscosity, however, did not change during calcium supplementation. Oral calcium supplementation in these men was accompanied by a reduction in the plasma concentrations of intact parathormone and 1,25-dihydroxyvitamin D3, and an increase in 24 h urinary calcium excretion, but no change in the plasma total calcium concentration, serum ionized calcium level, or plasma phosphate or 25-hydroxyvitamin D3. The intra-erythrocyte and intraplatelet potassium and magnesium concentrations as well as the activities of the erythrocyte Na,Li-countertransporter and Na,K-cotransporter, and sodium and potassium leakage did not change during calcium administration. The lowering of standing blood pressure seen in men with a high calcium intake is accompanied by a decrease in cytosolic free platelet calcium and total erythrocyte calcium, by a reduction in intraplatelet and intra-erythrocyte sodium concentration and erythrocyte membrane cholesterol and by an increase in the activity of the erythrocyte and platelet sodium-pump.
Journal of Hypertension, 2006
The aim of the present study was to determine whether inhibition of reduced nicotinamide adenine ... more The aim of the present study was to determine whether inhibition of reduced nicotinamide adenine dinucleotide (phosphate) [NAD(P)H] oxidase and of various superoxide generating systems could affect the collagen production, the mRNA and protein expression of collagen types I and III in control and angiotensin II-treated cardiac fibroblasts. Cardiac fibroblasts from passage 2 from normal male adult rats were cultured to confluency and incubated in serum-free Dulbecco's modified Eagle's medium for 24 h. The cells were then preincubated with(out) the tested inhibitors for 1 h and then further incubated with(out) angiotensin II (1 micromol/l) for 24 h. Collagen production was measured spectrophotometrically with picrosirius red as dye and with [3H]proline incorporation; collagen type I and III content by enzyme-linked immunosorbent assay and collagen type I and III mRNA expression by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR). NAD(P)H-dependent superoxide anion production was assayed as superoxide dismutase-inhibitable cytochrome c reduction. Intracellular formation of reactive oxygen species was assessed with 2',7'-dichlorofluorescein diacetate as fluorescent probe. Angiotensin II stimulated the collagen production, the collagen I and III content and mRNA expression in cardiac fibroblasts, and apocynin, a membrane NAD(P)H oxidase inhibitor, abolished this induction. Rotenone, allopurinol, indomethacin, nordihydroguiaretic acid, ketoconazole and nitro-L-arginine (inhibitors of mitochondrial NAD(P)H oxidase, xanthine oxidase, cyclooxygenase, lipoxygenase, cytochrome P450 oxygenase and nitric oxide synthase, respectively) did not affect the angiotensin II-induced collagen production. Angiotensin II increased the NAD(P)H-dependent superoxide anion production and the intracellular generation of reactive oxygen species in cardiac fibroblasts, and apocynin abrogated this rise. Our data show that in adult rat cardiac fibroblasts the membrane-associated NAD(P)H oxidase complex is the predominant source of superoxide anion and reactive oxygen species generation in angiotensin II-stimulated adult cardiac fibroblasts. Inhibition of this NAD(P)H oxidase complex with apocynin completely blocked the angiotensin II-stimulated collagen production, and collagen I and III protein and mRNA expression.
Journal of Molecular and Cellular Cardiology, 2000
P. L V. P. Induction of Cardiac Fibrosis by Aldosterone. Journal of Molecular and C... more P. L V. P. Induction of Cardiac Fibrosis by Aldosterone. Journal of Molecular and Cellular Cardiology (2000) 32, 865-879. An intracardiac aldosterone system which responds to short-and long-term physiological stimuli has been described. This cardiac generated aldosterone has possibly autocrine or paracrine actions.
American Journal of Hypertension, 2003
Discordant findings are reported on the left ventricular transforming growth factor-β1 (TGF-β1) m... more Discordant findings are reported on the left ventricular transforming growth factor-β1 (TGF-β1) mRNA levels in various rat models. Left ventricular TGF-β1 mRNA levels did not differ between spontaneously hypertensive rats (SHR) and normal rats, between deoxycorticosterone (DOCA)-salt and sham-operated hypertensive rats, but were increased in stroke-prone spontaneously hypertensive rats (SHRSP) and in post-myocardial infarction (MI) rats. Renal cortical TGF-β1 mRNA
European Journal of Biochemistry, 1994
Human atrial natriuretic peptide (ANP) fragments ANP-(127-150) or ANP-I11 and ANP-(127-149) or AN... more Human atrial natriuretic peptide (ANP) fragments ANP-(127-150) or ANP-I11 and ANP-(127-149) or ANP-I1 activate Na+/H+ exchange in human erythrocytes at concentrations as low as 1 pM. Both ANP-(127-147) or ANP-I and ANP-(129-150) or des-Ser5, Ser6-ANP-I11 have no effect on erythrocyte Na+/H+ exchange. ANP-I11 also produces a time-dependent increase of intraerythrocyte guanosine 3',5'-phosphate (cGMP) Concentration. M&B 22,948, a specific inhibitor of cGMP phosphodiesterase, increases Na+/H+ exchange and the intracellular concentration of cGMP. Both 8bromoguanosine 3',5'-phosphate (8-Br-cGMP) and dibutyryl-cGMP mimic the effect of ANP-I11 on erythrocyte Na+/H+ exchange. Our data suggest that human erythrocytes possess guanylate-cyclase activity stimulated by ANP-I11 and that activation of Na+/H+ exchange by this peptide is mediated by cGMP. Human erythrocytes display a high degree of sensitivity to ANP-I11 or ANP-I1 and a specificity for ANP-fragment structures just as cells with established ANP-specific receptors.
We derive a new non-abelian Stokes theorem by rewriting the Wilson loop as a gauge-invariant area... more We derive a new non-abelian Stokes theorem by rewriting the Wilson loop as a gauge-invariant area integral, at the price of integrating over an auxiliary field from the coset SU(N) / [U(1)]^{N-1} space. We then introduce the relativistic quark--monopole interaction as a Wess--Zumino-type action, and extend it to the non-abelian case. We show that condensation of monopoles and confinement can be investigated in terms of the behaviour of the monopole world lines. One can thus avoid hard problems of how to introduce monopole fields and dual Yang--Mills potentials.
European Physical Journal A, 1997
We predict an exotic Z + baryon (having spin 1/2, isospin 0 and strangeness +1) with a relatively... more We predict an exotic Z + baryon (having spin 1/2, isospin 0 and strangeness +1) with a relatively low mass of about 1530 M eV and total width of less than 15 M eV . It seems that this region of masses has avoided thorough searches in the past.
In the limit of large number of colors N the nucleon consisting of N quarks is heavy, and one can... more In the limit of large number of colors N the nucleon consisting of N quarks is heavy, and one can treat it semiclassically, like the large-Z Thomas--Fermi atom. The role of the semiclassical field binding the quarks in the nucleon is played by the pion or chiral field; its saddle-point distribution inside the nucleon is called the chiral soliton. The old Skyrme model for this soliton is an over-simplification. One can do far better by exploiting a realistic and theoretically-motivated effective chiral lagrangian presented in this paper. As a result one gets not only the static characteristics of the nucleon in a fair accordance with the experiment (such as masses, magnetic moments and formfactors) but also much more detailed dynamic characteristics like numerous parton distributions. We review the foundations of the Chiral Quark-Soliton Model of the nucleon as well as its recent applications to parton distributions, including the recently introduced `skewed' distributions, and to the nucleon wave function on the light cone.
Physical Review D, 2004
We calculate exactly functional determinants for quantum oscillations about periodic instantons w... more We calculate exactly functional determinants for quantum oscillations about periodic instantons with non-trivial value of the Polyakov line at spatial infinity. Hence, we find the weight or the probability with which calorons with non-trivial holonomy occur in the Yang--Mills partition function. The weight depends on the value of the holonomy, the temperature, Lambda_QCD, and the separation between the BPS monopoles (or dyons) which constitute the periodic instanton. At large separation between constituent dyons, the quantum measure factorizes into a product of individual dyon measures, times a definite interaction energy. We present an argument that at temperatures below a critical one related to Lambda_QCD, trivial holonomy is unstable, and that calorons ``ionize'' into separate dyons.
Journal of Experimental and Theoretical Physics, 2000
We perform the dual transformation of theYang-Mills theory in three dimensions using the Wilson a... more We perform the dual transformation of theYang-Mills theory in three dimensions using the Wilson action on the cubic lattice. The dual lattice is made of tetrahedra triangulating a 3-dimensional curved manifold but which is embedded into a flat 6-dimensional space [for the SU(2) gauge group]. In the continuum limit, the theory can be reformulated in terms of 6-component gauge-invariant scalar fields having the meaning of the external coordinates of the dual lattice sites. These 6-component fields induce a metric and a curvature of the 3-dimensional dual-color space. The Yang-Mills theory can also be rewritten as a quantum gravity theory with the Einstein-Hilbert action but with a purely imaginary Newton constant plus a homogeneous “ether” term. The theory can be formulated in a gauge-invariant and local form without explicit color degrees of freedom.
Physical Review D, 2004
We analyze what consequences has the observation of exotic pentaquark baryons on the location of ... more We analyze what consequences has the observation of exotic pentaquark baryons on the location of the non-exotic baryons belonging to the antidecuplet. We suggest that there must be a new nucleon state at 1650-1690 MeV and a new Sigma baryon at 1760-1810 MeV.
American Journal of Hypertension, 1998
To evaluate the role of intracellular calcium and particularly Ca 2؉ uptake in the initiation of ... more To evaluate the role of intracellular calcium and particularly Ca 2؉ uptake in the initiation of lymphocyte mitogenesis, the effect of mibefradilwhich blocks both L-and T-type calcium channels with a more selective blockade of T-type channels-on the proliferation of human peripheral blood mononuclear cells (PBMC) is compared with the effect of nifedipine, which blocks only the L-type calcium channel. The rate of 3 H-thymidine, 3 H-uridine, and 3 H-leucine incorporation into control and concanavalin Astimulated PBMC in the presence or absence of the calcium channel blockers mibefradil or nifedipine (1, 10, or 50 mol/L), and of the intracellular calcium antagonist TMB-8 or the calmodulin antagonist W-7 (1, 10, 25, or 50 mol/L) was assayed in cells cultured for 3 days. The cellular cytotoxicity and the cell number in growing cultures was also determined in mibefradil-or nifedipine-treated control or stimulated cells. Mibefradil and nifedipine reduced the cell number and the 3 H-thymidine, 3 H-uridine, or 3 H-leucine incorporation or the de novo DNA, RNA, or protein synthesis in control and concanavalin Astimulated human PBMC in a concentrationdependent manner. Mibefradil exhibited a more pronounced inhibition than nifedipine. The inhibitory effect of mibefradil or nifedipine on DNA synthesis was dependent upon the timing of treatment with the drugs. The inhibitory effect of mibefradil or nifedipine on the lymphoproliferative response was nearly abolished if the drugs were added 20 h after cell stimulation. A markedly reduced inhibitory effect was found when mibefradil or nifedipine were added 1 to 7 h after cell stimulation. However, regardless of time of addition, TMB-8 and W-7 caused a persistent inhibition of the proliferation of human PBMC. Our data show that mibefradil had a more pronounced inhibitory effect on the proliferation of human PBMC than nifedipine and that this inhibitory effect on de novo DNA synthesis was dependent upon the timing of treatment with both drugs. Mibefradil and nifedipine also reduce RNA and protein synthesis in human PBMC. Therefore, administration of these calcium channel blockers to inhibit cellular proliferation might be most beneficial at anatomic sites where cellular proliferation is not already an active process, while being ineffective in the presence of ongoing active proliferation, as suggested by some prospective studies. Am
American Journal of Hypertension, 1999
A double blind, placebo-controlled, parallel study was conducted on the effect of a high daily or... more A double blind, placebo-controlled, parallel study was conducted on the effect of a high daily oral calcium supplementation of 1 g elemental calcium, given twice daily for 16 weeks in normal male subjects, on plasma renin, aldosterone, kallikrein, cGMP, cAMP, and calciotropic hormones, intracellular calcium concentrations, and plasma total and ionized calcium. After a 1-month run-in period on a limited use of dairy products, the subjects (n ؍ 32) were allocated to a placebo or a calcium group. Placebo or 1 g elemental calcium was administered twice daily in the morning and evening for 16 weeks. All subjects were investigated at baseline and after 1, 2, 4, 8, and 16 weeks of placebo or calcium administration.
American Journal of Hypertension, 2000
To investigate whether the aminopeptidase B and leucine aminopeptidase inhibitor bestatin, the ch... more To investigate whether the aminopeptidase B and leucine aminopeptidase inhibitor bestatin, the chymase inhibitor chymostatin, the calpain inhibitor E-64 and the neub-al sedne protease inhibitor leupeptin affect the angiotensin converting enzyme (ACE) activity in T-lymphecytes. ACE-activity in homogenates of T-lymphecytes or in intact T-lymphocytes in suspension was measured by determing fluonmetncally histidyl-leucine, formed from the conversion of hippurylhistidyl-leucine, coupled with o-phtaldialdehyde. The effect of various concentrations (10-~ -10 .3 M) of the angiotensin-converting enzyme inhibitors lisinopril and captopdl and of the venous protease inhibitors on ACE-activity was studied. Lisinopril and captopnl concentration-dependently reduce the ACEactivity in homogenates of T-lymphocytes. Lisinopdl exhibit a more pronounced inhibition of ACE in T-tymphocytes than captopdl. Chymostatin and E-64 have no effect on the ACE-activity in
Journal of Hypertension, 1995
A double-blind, placebo-controlled parallel-group study was conducted on the effect of a high lev... more A double-blind, placebo-controlled parallel-group study was conducted on the effect of a high level of daily oral calcium supplementation (1 g elemental calcium given twice a day for 16 weeks) in normal male subjects on blood pressure, intracellular cationic concentrations and transmembrane cation transport systems, plasma total and ionized calcium, and calciotropic hormones. After a 1-month run-in period with a limited intake of dairy products, the 32 subjects were allocated to a placebo or a calcium group. Placebo or 1 g elemental calcium was administered twice a day, in the morning and evening, for 16 weeks. All subjects were investigated at baseline and after 1, 2, 4, 8 and 16 weeks of placebo or calcium administration. Compared with the placebo group, standing systolic blood pressure was decreased in the calcium group, whereas the standing diastolic blood pressure tended to decrease. The changes in supine systolic and diastolic blood pressure did not differ between the placebo and calcium groups. Decreased intra-erythrocyte and intraplatelet sodium and calcium concentrations, an increased activity of platelet and erythrocyte sodium-pump activity and a reduced membrane cholesterol content were observed in the calcium-treated subjects. Erythrocyte membrane surface and core microviscosity, however, did not change during calcium supplementation. Oral calcium supplementation in these men was accompanied by a reduction in the plasma concentrations of intact parathormone and 1,25-dihydroxyvitamin D3, and an increase in 24 h urinary calcium excretion, but no change in the plasma total calcium concentration, serum ionized calcium level, or plasma phosphate or 25-hydroxyvitamin D3. The intra-erythrocyte and intraplatelet potassium and magnesium concentrations as well as the activities of the erythrocyte Na,Li-countertransporter and Na,K-cotransporter, and sodium and potassium leakage did not change during calcium administration. The lowering of standing blood pressure seen in men with a high calcium intake is accompanied by a decrease in cytosolic free platelet calcium and total erythrocyte calcium, by a reduction in intraplatelet and intra-erythrocyte sodium concentration and erythrocyte membrane cholesterol and by an increase in the activity of the erythrocyte and platelet sodium-pump.
Journal of Hypertension, 2006
The aim of the present study was to determine whether inhibition of reduced nicotinamide adenine ... more The aim of the present study was to determine whether inhibition of reduced nicotinamide adenine dinucleotide (phosphate) [NAD(P)H] oxidase and of various superoxide generating systems could affect the collagen production, the mRNA and protein expression of collagen types I and III in control and angiotensin II-treated cardiac fibroblasts. Cardiac fibroblasts from passage 2 from normal male adult rats were cultured to confluency and incubated in serum-free Dulbecco's modified Eagle's medium for 24 h. The cells were then preincubated with(out) the tested inhibitors for 1 h and then further incubated with(out) angiotensin II (1 micromol/l) for 24 h. Collagen production was measured spectrophotometrically with picrosirius red as dye and with [3H]proline incorporation; collagen type I and III content by enzyme-linked immunosorbent assay and collagen type I and III mRNA expression by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR). NAD(P)H-dependent superoxide anion production was assayed as superoxide dismutase-inhibitable cytochrome c reduction. Intracellular formation of reactive oxygen species was assessed with 2',7'-dichlorofluorescein diacetate as fluorescent probe. Angiotensin II stimulated the collagen production, the collagen I and III content and mRNA expression in cardiac fibroblasts, and apocynin, a membrane NAD(P)H oxidase inhibitor, abolished this induction. Rotenone, allopurinol, indomethacin, nordihydroguiaretic acid, ketoconazole and nitro-L-arginine (inhibitors of mitochondrial NAD(P)H oxidase, xanthine oxidase, cyclooxygenase, lipoxygenase, cytochrome P450 oxygenase and nitric oxide synthase, respectively) did not affect the angiotensin II-induced collagen production. Angiotensin II increased the NAD(P)H-dependent superoxide anion production and the intracellular generation of reactive oxygen species in cardiac fibroblasts, and apocynin abrogated this rise. Our data show that in adult rat cardiac fibroblasts the membrane-associated NAD(P)H oxidase complex is the predominant source of superoxide anion and reactive oxygen species generation in angiotensin II-stimulated adult cardiac fibroblasts. Inhibition of this NAD(P)H oxidase complex with apocynin completely blocked the angiotensin II-stimulated collagen production, and collagen I and III protein and mRNA expression.
Journal of Molecular and Cellular Cardiology, 2000
P. L V. P. Induction of Cardiac Fibrosis by Aldosterone. Journal of Molecular and C... more P. L V. P. Induction of Cardiac Fibrosis by Aldosterone. Journal of Molecular and Cellular Cardiology (2000) 32, 865-879. An intracardiac aldosterone system which responds to short-and long-term physiological stimuli has been described. This cardiac generated aldosterone has possibly autocrine or paracrine actions.
American Journal of Hypertension, 2003
Discordant findings are reported on the left ventricular transforming growth factor-β1 (TGF-β1) m... more Discordant findings are reported on the left ventricular transforming growth factor-β1 (TGF-β1) mRNA levels in various rat models. Left ventricular TGF-β1 mRNA levels did not differ between spontaneously hypertensive rats (SHR) and normal rats, between deoxycorticosterone (DOCA)-salt and sham-operated hypertensive rats, but were increased in stroke-prone spontaneously hypertensive rats (SHRSP) and in post-myocardial infarction (MI) rats. Renal cortical TGF-β1 mRNA
European Journal of Biochemistry, 1994
Human atrial natriuretic peptide (ANP) fragments ANP-(127-150) or ANP-I11 and ANP-(127-149) or AN... more Human atrial natriuretic peptide (ANP) fragments ANP-(127-150) or ANP-I11 and ANP-(127-149) or ANP-I1 activate Na+/H+ exchange in human erythrocytes at concentrations as low as 1 pM. Both ANP-(127-147) or ANP-I and ANP-(129-150) or des-Ser5, Ser6-ANP-I11 have no effect on erythrocyte Na+/H+ exchange. ANP-I11 also produces a time-dependent increase of intraerythrocyte guanosine 3',5'-phosphate (cGMP) Concentration. M&B 22,948, a specific inhibitor of cGMP phosphodiesterase, increases Na+/H+ exchange and the intracellular concentration of cGMP. Both 8bromoguanosine 3',5'-phosphate (8-Br-cGMP) and dibutyryl-cGMP mimic the effect of ANP-I11 on erythrocyte Na+/H+ exchange. Our data suggest that human erythrocytes possess guanylate-cyclase activity stimulated by ANP-I11 and that activation of Na+/H+ exchange by this peptide is mediated by cGMP. Human erythrocytes display a high degree of sensitivity to ANP-I11 or ANP-I1 and a specificity for ANP-fragment structures just as cells with established ANP-specific receptors.