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Biomedical subjects

A Casini

Publications and source records attributed to A Casini.

At least 37 records · Page 2Linked to original sources
PubMed2000

DNA as a possible target for antitumor ruthenium(III) complexes.

The interaction of two experimental ruthenium(III)-containing antitumor complexes-Na[trans-RuCl(4)(DMSO)(Im)] (NAMI) and dichloro(1,2-propylendiaminetetraacetate)ruthenium(III) (RAP)-with DNA was investigated through a number of spectroscopic and molecular biology techniques, including spectrophotometry, circular dichroism, gel shift analysis, and restriction enzyme inhibition. It was found that both complexes slightly alter DNA conformation, modify its electrophoretic mobility, and inhibit DNA recognition and cleavage by some restriction enzymes, though they were less effective than cisplatin in producing such effects. Notably, the effects produced by NAMI on DNA were much larger than those induced by RAP. Implications of these results for the mechanism of action of ruthenium(III) antitumor complexes are discussed.

Animals↗
PubMed2000

Collagen type I synthesized by pancreatic periacinar stellate cells (PSC) co-localizes with lipid peroxidation-derived aldehydes in chronic alcoholic pancreatitis.

Chronic alcoholic pancreatitis (CAP) is characterized by progressive pancreatic fibrosis and loss of the acinar cell mass, but the pathogenesis of pancreatic fibrosis in the human is poorly understood. It has been recently suggested that lipid peroxidation-derived aldehydes such as 4-hydroxynonenal (HNE) are involved in tissue damage and fibrosis in other organs. The aim of this study was to evaluate the role of oxidative stress in the development of alcohol-induced pancreatic fibrosis in humans, and to assess the contribution of pancreatic periacinar stellate cells (PSC) in the in vivo synthesis of extracellular matrix components during CAP. Lipid peroxidation was evaluated in tissue specimens obtained from patients with CAP who underwent surgical procedures, by immunohistochemistry using a monoclonal antibody directed against HNE-protein adducts. Immunohistochemical determination of collagen type I, alpha-smooth muscle actin (alpha-SMA), and the beta subunit of human platelet-derived growth factor (PDGF-Rbeta) was also performed. In addition, the tissue mRNA expression of procollagen I, PDGF-Rbeta, and transforming growth factor-beta1 (TGF-beta1) was evaluated by in situ hybridization. In CAP, increased formation of HNE-protein adducts was evident in acinar cells adjacent to the interlobular connective tissue that stained positively for collagen type I. HNE staining was absent in normal pancreas. Several non-parenchymal periacinar cells (PSC) underlay the HNE-stained acinar cells. Those PSC stained positively for alpha-SMA and PDGF-Rbeta and showed active synthesis of procollagen type I by in situ expression of the specific mRNAs. The pattern of expression of PDGF-Rbeta mRNA reflected that observed in immunostaining, showing increased amounts of transcripts in PSC. TGF-beta1 mRNA expression was increased in CAP, but transcripts were found in several cell types including PSC, acinar, and ductal cells. These results indicate that significant lipid peroxidation phenomena occur in CAP and that they are associated with active synthesis of collagen by PSC.

Actins↗
PubMed2000

Peroxisome proliferator-activated receptor gamma transcriptional regulation is involved in platelet-derived growth factor-induced proliferation of human hepatic stellate cells.

During liver injury, hepatic stellate cells (HSC) acquire a myofibroblast-like phenotype associated with reduction of lipid droplets, increased collagen synthesis, and proliferation. Peroxisome proliferator-activated receptor gamma (PPARgamma) regulates adipocyte differentiation and controls gene transcription in response to various activators including prostanoids and antidiabetic thiazolidinediones. We explored whether the presence of PPARgamma and its transcriptional activity were involved in control of HSC proliferation in vitro. PPARgamma ligands, 15-deoxy-triangle up(1214) prostaglandin J(2) (15d-PGJ(2)) and ciglitizone, significantly decrease platelet-derived growth factor (PDGF)-induced proliferation in activated human HSC and inhibit alpha smooth muscle actin (alpha-SMA) expression during HSC transdifferentiation. Treatment with 9-cis retinoic acid (9-cisRA) and LG268, ligands of the heterodimerization partner retinoic X receptor (RXR), had a negligible effect in PDGF-treated cells but caused a further reduction of proliferation when used in combination with ciglitizone. Transfection experiments with a reporter gene consisting of 3 copies of a PPAR response element (peroxisome proliferator response element [PPRE](3)-tk-luciferase) showed a progressive reduction of PPAR transcriptional activity during plastic-induced HSC transdifferentiation. Cotransfection with human PPARgamma expression vector restored the PPRE(3)-tk-luciferase reporter expression and the increased level of the receptor in activated HSC-inhibited cell proliferation in a dose-dependent manner. Incubation of human PPARgamma-cotransfected HSC with PDGF strongly inhibited luciferase activity and this effect was blocked by the inhibition of the mitogen-activated protein (MAP) kinase signal cascade. Our results indicate that depression of PPARgamma expression and activity is involved in HSC proliferation and that the PPARgamma ligand-mediated activation exerts a previously unrecognized inhibition of PDGF-induced mitogenesis in activated human HSC.

Cell Differentiation↗
PubMed2000

Immunohistochemical localization of amylin in rat brainstem.

Immunohistochemical studies were conducted on rat brainstem using a specific polyclonal antiserum against the COOH-terminal (25-37) of human amylin. Amylin-immunoreactive cell bodies were observed in the vestibular, cochlear, trapezoid, and inner cerebellar nuclei and in the mesencephalic nucleus of trigeminal nerve. Positive cell bodies were also found in lateral, gigantocellular and magnocellular reticular nuclei. Numerous amylin-immunoreactive nerve fibers were shown in the trigeminal spinal tract, in the solitary area and in the area postrema. Amylin-immunoreactive cell bodies were often surrounded by a network of tyrosine hydroxylase-immunoreactive nerve fibers. These results provide morphologic evidence that amylin may play a role in some discrete sensory functions.

Amyloid↗
PubMed2000

Carbonic anhydrase inhibitors: sulfonamides incorporating furan-, thiophene- and pyrrole-carboxamido groups possess strong topical intraocular pressure lowering properties as aqueous suspensions.

Important physiological and physio-pathological functions are played by several carbonic anhydrase (CA, EC 4.2.1.1) isozymes, which are strongly inhibited by aromatic and heterocyclic sulfonamides. Here we report several new types of such sulfonamides, incorporating furan-, thiophene- and pyrrole-carboxamide moieties in their molecules. Some of these compounds showed very good CA II and CA IV inhibitory properties. with affinities for the enzymes in the low nanomolar range. Due to their relatively low water solubility, some of the most active CA II inhibitors reported here have been formulated as aqueous suspension for topical administration as antiglaucoma agents. in normotensive and glaucomatous rabbits. The derivatives incorporating furan- and pyrrole-carboxamide moieties (but not the corresponding thiophene-substituted derivatives), showed effective and long-lasting intraocular pressure (IOP) lowering both in normotensive as well as glaucomatous animals, with potencies superior to dorzolamide and brinzolamide, the two available topically acting sulfonamide drugs. This is the first example of non-water soluble sulfonamides that significantly lower IOP, being thus similar with the recently introduced drug brinzolamide, which belongs to a completely different chemical family of antiglaucoma sulfonamides.

Animals↗
PubMed1999

Role of calcium in the reaction between pyrroloquinoline quinone and pyridine nucleotides monomers and dimers.

Redox reactions were carried out in aerobiosis and anaerobiosis between NAD(P) dimers or NAD(P)H and pyrroloquinoline quinone (PQQ) in different buffers. The buffer system and pH significantly affected the oxidation rates of nucleotides and the ESR signal intensity of the PQQ(*) radical formed in anaerobiosis by comproportion between the quinone and quinol forms. The relative reactivity of the four nucleotides toward PQQ was affected by pH and buffer nature. PQQ, which behaves as an electron shuttle from nucleotides to oxygen, was first converted to PQQH(2) and then rapidly reoxidized by oxygen, with formation of hydrogen peroxide. Both NAD(P) dimers and NAD(P)H consumed 1 mol of oxygen per mole of reacted molecule of pyridine nucleotide, yielding 1 or 2 mol of NAD(P)(+) from NAD(P)H or from NAD(P) dimers, respectively. Chelating agents such as EDTA and phytate strongly decreased the reaction rate and the PQQ(*) radical signal intensity. Kinetics carried out in the presence of metal ions showed instead an increased reaction rate in the order Ca(2+) >> Mg(2+) > Na(+) >> K(+). Spectrofluorimetric measurements of PQQ with increasing concentrations of Ca(2+) showed a fluorescence quenching and shift of the maximum emission toward lower wavelengths, while other metal ions showed minor effects, if any. Therefore, it is demonstrated that Ca(2+) binds to PQQ, probably forming a complex which is more reactive with both one-electron (NAD(P) dimers) or two-electron donors (NAD(P)H) in nonenzymic reactions. It is important to recall that Ca(2+) was already found to play active role in PQQ-containing enzymes.

Calcium↗
PubMed1999

Functions of the fibrinolytic system in human Ito cells and its control by basic fibroblast and platelet-derived growth factor.

During liver fibrogenesis, hepatic stellate cells (HSC) proliferate and migrate under the influence of growth factors, including platelet-derived growth factor (PDGF) and basic-fibroblast growth factor (b-FGF). The plasminogen activation system regulates extracellular matrix (ECM) catabolism and cell movement. We evaluated the expression and biological functions of the plasminogen activation system in human HSC and its interaction with PDGF and b-FGF. Urokinase-plasminogen activator receptors (u-PAR) were measured by radioligand binding, cell cross-linking, immunoassay, and RNAse protection assay. u-PA and plasminogen activator inhibitors (PAIs) expression and activities were analyzed by zymography, immunoassay, and RNase protection assay. Cell migration and proliferation, studied in Boyden chambers and by microscopic counting, were evaluated after the addition of PDGF, b-FGF, and blockade with anti-u-PA, anti-u-PAR antibodies, and antisense oligodeoxynucleotides (aODN) against u-PAR mRNA. We have shown that HSC produce u-PAR, u-PA, and PAI-1. PDGF and b-FGF up-regulate u-PA and u-PAR, but not PAI-1, and exogenous addition of u-PA stimulates HSC proliferation, chemotaxis, and chemoinvasion. Inhibition of u-PA/u-PAR with antibodies against u-PA or u-PAR and with u-PAR aODN inhibit the proliferative, chemotactic, and chemoinvasive activity of PDGF and b-FGF. These findings indicate that u-PA and u-PAR are required for the mitogenic and chemoinvasive activity of PDGF and b-FGF on HSC.

Cell Division↗
PubMed1999

Insulin and insulin-like growth factor-1 stimulate proliferation and type I collagen accumulation by human hepatic stellate cells: differential effects on signal transduction pathways.

Insulin and insulin-like growth factor (IGF-1) are mitogenic for fibroblasts and smooth muscle cells. IGF-1 increases in inflamed and fibrotic tissues and induces proliferation of rat hepatic stellate cells (HSC). This study evaluates the potential roles of these hormones in the development of liver fibrosis. Insulin and IGF-1 receptor expression was evaluated by immunohistochemistry in both cultured human HSC and human liver tissue. Phosphorylation of both 70-kd S6 kinase and extracellular-regulated kinase (ERK), cell proliferation, type I collagen gene expression, and accumulation in HSC culture media were evaluated by Western blot, immunohistochemistry for bromodeoxyuridine (BrdU), Northern blot, and enzyme-linked immunosorbent assay, respectively. Insulin and IGF-1 receptors were detected in HSC in vitro and in liver sections from patients with chronic active hepatitis. Insulin and IGF-1 induced 70-kd S6 kinase phosphorylation in HSC, whereas IGF-1 only induced ERK phosphorylation. Insulin and IGF-1 stimulated HSC proliferation in a dose-dependent fashion, with IGF-1 being four to five times more potent than insulin. Cell exposure to specific inhibitors showed that both phosphatidylinositol 3-kinase (PI3-K) and ERK are involved in IGF-1-induced mitogenesis, whereas insulin stimulated mitogenesis through a PI3-K-dependent ERK-independent pathway. IGF-1 increased type I collagen gene expression and accumulation in HSC culture media through a PI3-K- and ERK-dependent mechanism. In conclusion, insulin and IGF-1, which stimulate HSC mitogenesis and collagen synthesis, may act in concert to promote liver fibrosis in vivo by a differential activation of PI3-K- and ERK1-dependent pathways.

Androstadienes↗
PubMed1999

Loop diuretics enhance the secretion of prostacyclin in vitro, in healthy persons, and in patients with chronic heart failure.

BACKGROUND: Previous studies suggest that the acute haemodynamic effects of loop diuretics are due to a direct dilation of blood vessels and are not related to diuretic properties, but possibly to prostaglandin secretion. OBJECTIVES: We investigated whether in vitro human endothelial and renal epithelial cells responded to torasemide or furosemide with enhanced secretion of the vasodilator prostaglandin prostacyclin (PGI2). We also investigated the effects of loop diuretics on plasma concentrations of PGI2 and its physiological antagonist thromboxane after 25 min of administration of drugs in 44 patients with congestive heart failure (CHF) and 44 healthy volunteers. METHODS: The PGI2 levels were measured after extraction in ethyl acetate by RIA as levels of 6-KetoPGF1alpha, a stable metabolite from a non-enzymatic degradation. TxB2 concentration, the stable hydrolysis product of TxA2, was also measured by RIA. RESULTS: In human endothelial and renal epithelial cells, both loop diuretics induced an increase of 6-KetoPGF1alpha secretion that reached a peak after about 5 min and remained stable for 30 min of exposure to the drugs. The magnitude of the phenomenon was lesser in epithelial than in endothelial cells. Moreover, in both cell lines, there was a significantly higher secretion of 6-KetoPGF1alpha to torasemide than furosemide (P < 0.05). Concentrations of 6-KetoPGF1alpha at baseline were similar between the groups of CHF patients receiving the two different drugs. After 25 min of both drugs, 6-Keto-PGF1alpha significantly increased (P < 0.01), and this was significantly higher in patients treated with 10 mg of torasemide (P < 0.05 vs furosemide). Levels of PGI2 at baseline were lower in healthy controls than those reached by CHF patients and similar between groups. After 25 min of both drugs, PGI2 plasma levels were significantly increased (P < 0.01). Baseline values of TxB2 were significantly higher in CHF patients compared with controls (P < 0.01 vs respective groups). and, more importantly, furosemide but not torasemide increased TxB2 levels in patients and controls (P < 0.05 vs baseline). CONCLUSIONS: Our study is the first demonstration in human tissue of increased secretion of PGI2 both in vitro and in vivo, after torasemide or furosemide administration. This phenomenon, which may explain in part the vasodilatory effects of these drugs, was more evident with torasemide and was reached at lower concentrations of the drug. Accordingly, we also found that furosemide but not torasemide stimulated the release of the PGI2 physiological antagonist thromboxane in CHF patients and healthy controls.

6-Ketoprostaglandin F1 alpha↗
PubMed1999

Ethanol-induced alterations of matrix network in the duodenal mucosa of chronic alcohol abusers.

Excessive consumption of alcoholic beverages may be associated with gastrointestinal symptoms, including dyspepsia and diarrhoea. It is not clear whether or not chronic alcohol ingestion damages the mucosa of the small intestine. We investigated the effect of chronic alcohol abuse on the duodenal mucosa, and particularly on its extracellular matrix (ECM) network. Duodenal biopsy specimens were obtained during upper gastrointestinal endoscopy from 50 chronic alcoholics without cirrhosis and 10 healthy subjects. Morphological studies were performed by routine histology, immunohistochemistry and electron microscopy. Morphometry of duodenal tissues was performed with a computerized image analyser. No significant duodenal epithelial changes were found in alcoholics, despite an evident reduction in the enterocyte turnover. Myofibroblast-like cells were significantly increased in the villus stroma of alcoholics in comparison to controls. These cells stained positively for desmin, alpha-smooth muscle actin and for several ECM components. In alcohol abusers the thickness of the mucosal basement membrane was greater and the staining for collagen I and III was enhanced both in the basement membrane and in the villus stroma. A higher expression of tenascin was also seen at the base of villi of alcoholics. Chronic alcohol abuse may induce fibrosis of duodenal villi which is associated with a transformation of villus juxta-parenchymal cells into active subepithelial myofibroblast-like cells able to produce different ECM components.

Adult↗
PubMed1999

Immunoscintigraphy of atherosclerotic uncomplicated lesions in vivo with a monoclonal antibody against D-dimers of insoluble fibrin.

To test the effectiveness of a new F(ab')2 monoclonal antibody against human fragment D-dimer of cross-linked fibrin in the detection of uncomplicated atherosclerotic lesions of the carotid vessel previously documented at echo-color-Doppler and selective arteriographic study, 8 patients underwent a scintigraphic study including dynamic and early and delayed (3 h later) static imaging of the neck after injection of a bolus of 99mTc-labeled monoclonal antibody, and were subsequently operated. Vessel specimens and blood samples were drawn at operation and counted. No adverse reaction occurred after administration of the monoclonal antibody. The atherosclerotic lesion appeared as a focal area of asymmetrical tracer uptake, already visible at early images in four patients, and at delayed images in five. The average tracer uptake ratio between pathological and normal vessels was 1.40+0.24 (P < 0.05) at time-activity curves derived from dynamic images, 2.17+/-0.97 (P < 0.05) at early static images and 2.05+/-0.98 (P < 0.05) at delayed static images, respectively. Mean vessel to blood uptake rate of specimens obtained at operation was 2.22+/-0.59 (P < 0.001). The study shows that the 99mTc-labeled antibody was found to be safe and capable of detecting atherosclerotic plaques in humans.

Aged↗
PubMed1999

The Na+/H+ exchanger modulates the fibrogenic effect of oxidative stress in rat hepatic stellate cells.

BACKGROUND/AIMS: Oxidative stress is associated with liver fibrosis in vivo and with hepatic stellate cell (HSC) activation in vitro, but the intracellular mechanisms mediating these effects are mostly unknown. The Na+/H+ exchanger plays a key role in regulating the cell cycle, and is involved in HSC proliferation. Its role in different HSC features, such as collagen accumulation, is still unknown. We thus evaluated if the Na+/H+ exchanger modulates the fibrogenic effect of oxidative stress in rat HSC. METHODS: HSC were incubated with 0.1 mM ferric nitrilotriacetate complex (FeNTA). Intracellular hydroperoxides and malonildialdehyde (MDA) levels in the culture media were measured by the dichlorofluorescein and TBARS method, respectively. Intracellular pH and Na+/H+ exchanger activity were measured using the fluorescent dye BCECF. Cell proliferation was measured by immunohistochemistry for bromodeoxyuridine incorporation. Collagen type I accumulation in the culture media was measured by ELISA. RESULTS: HSC incubation with FeNTA resulted in a significant production of intracellular hydroperoxides and MDA, associated with increased Na+/H+ exchange activity and baseline intracellular pH (pHi). Exposure of HSC to FeNTA significantly enhanced the number of proliferating HSC and collagen type I levels in the culture medium. All these effects were reversed by the antioxidant resveratrol and by the Na+/H+ exchanger inhibitor amiloride. CONCLUSIONS: This study indicates that the Na+/H+ exchanger might represent a common mediator of the different effects induced by oxidative stress on HSC. The reduction in cell proliferation and collagen synthesis induced by amiloride could represent a new therapeutic challenge in liver fibrosis.

Animals↗
PubMed1999

Beneficial effects of ACE-inhibition with zofenopril on plaque formation and low-density lipoprotein oxidation in watanabe heritable hyperlipidemic rabbits.

The effects of angiotensin-converting enzyme (ACE)-inhibition with zofenopril on the development of atherosclerosis and low-density lipoprotein (LDL) oxidation were determined in Watanabe Heritable Hyperlipidemic (WHHL) rabbits. Rabbits received either placebo (n = 6) or 0.5 mg/kg/day of zofenopril (n = 6). After 6 weeks of treatment, the computer-assisted analysis revealed that zofenopril reduced the aortic and common carotid corrected cumulative lesion area by 34% and 39%, respectively (p < 0.05 vs placebo-treated group). The intimal/medial ratio of the largest fatty streaks was 0.426+/-0.158 in the zofenopril-treated group and 0.875+/-0.238 in the placebo-treated group (p < 0.05). Furthermore, we found in the zofenopril-treated group smaller lesions with an intimal/medial ratio of zofenopril also reduced plasmatic LDL oxidation, as shown by significant reduction of malondialdehyde content (p < 0.01) and relative agarose gel mobility (p < 0.05), as well as by the prolongation of the lag-time (p < 0.05). Compared to zofenopril-treated rabbits, arterial sections of the placebo-group had significant increase in the intimal presence of macrophages-derived foam cells (p < 0.05), ox-LDL (p < 0.01), and native LDL (p < 0.01) detected by immunocytochemistry with RAM-11, MDA2 and NP1533975 monoclonal antibodies, respectively. To investigate the amount of platelet accumulation in the atherosclerotic plaque we also measured platelet-associated radioactivity. Autologous platelets were labeled with 111Indiumoxine and injected intravenously. After 2 hours, WHHL were sacrificed and arterial sections were counted for platelet-associated radioactivity. In the placebo-treated group, platelet radioactivity was 0.52+/-0.12 equivalent of radioactivity per mg of tissue in the common carotid and 0.25+/-0.18 in the abdominal aorta; in contrast, rabbits treated by zofenopril had 0.20+/-0.12 in the common carotid and 0.06+/-0.01 in the abdominal aorta. These data indicate that ACE-inhibition with zofenopril has antiatherosclerotic and antioxidant effects in WHHL-rabbits. Our results also shows that these effects could be linked to a reduced wall-associated platelet deposition at the site of atherosclerotic lesions.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1999

Nitric oxide as a signaling molecule in the vascular system: an overview.

In retrospect, basic research in the fields of nitric oxide (NO) and cyclic guanosine monophosphate (cGMP) during the past two decades appears to have followed a logical course, beginning with the findings that NO and cGMP are vascular smooth muscle relaxants, that nitroglycerin relaxes smooth muscle by metabolism to NO, progressing to the discovery that mammalian cells synthesize NO, and finally the revelation that NO is a neurotransmitter mediating vasodilation in specialized vascular beds. A great deal of basic and clinical research on the physiologic and pathophysiologic roles of NO in cardiovascular function has been conducted since the discovery that endothelium-derived relaxing factor (EDRF) is NO. The new knowledge on NO should enable investigators in this field to develop novel and more effective therapeutic strategies for the prevention, diagnosis, and treatment of numerous cardiovascular disorders. The goal of this review was to highlight the early research that led to our current understanding of the pathophysiologic role of NO in cardiovascular medicine. Furthermore, we discussed the possible mechanism of some drugs interfering with NO signaling cascade.

Animals↗
PubMed1999

Acute amino acids supplementation enhances pituitary responsiveness in athletes.

PURPOSE: The purpose of this study was to determine the effect of a mixture of amino acids on pituitary responsiveness to a stimulation test (GnRH + CRH) in athletes. METHODS: In a double blinded counterbalanced experimental protocol, 10 moderately trained male athletes performed the pituitary stimulation test 60 min after a single oral administration of a placebo (P1-AS) or an amino acid mixture solution (AS) (L-arginine hydrochloride 100 mg x kg(-1) + L-ornithine hydrochloride 80 mg x kg(-1) + L-branched chain amino acids 140 mg x kg(-1): 50% L-leucine, 25% L-isoleucine, 25% L-valine) on two different occasions. Plasma ACTH, LH, FSH, GH, and cortisol were evaluated before (-60, -30, 0 min) and after (+15, +30, +45, +60, +90 min) the stimulation test. RESULTS: The ACTH, LH and FSH response to CRH + GnRH was significantly higher in AS group both as absolute values and area under curve (AUC) values than in P1-AS group. Pre-test and post-test cortisol AUC levels were significantly higher in P1-AS group although a higher percent increase in post-test cortisol was found in AS group. The total GH-AUC was higher in AS group and, as expected, the absolute GH concentrations at different time points were not influenced by CRH + GnRH administration. CONCLUSION: The amino acid mixture used enhanced the ACTH, LH, and FSH response to CRH + GnRH.

Adrenocorticotropic Hormone↗
PubMed1999

Evidence of exercise-induced myocardial ischemia in patients with primary aldosteronism: the Cross-sectional Primary Aldosteronism and Heart Italian Multicenter Study.

BACKGROUND: Primary aldosteronism (PA) is a disease associated with hypersecretion of aldosterone caused by an aldosterone-producing adrenal adenoma, bilateral adrenal hyperplasia, and, although rarely, by adrenal carcinoma. Arterial hypertension induces several cardiovascular alterations that yield a high cardiovascular risk. It has been shown that reduced myocardial perfusion at rest, assessed by thallium-201 myocardial scintigraphy, was greater in PA than in essential hypertension (EH). However, it is still unknown whether reduced myocardial perfusion at rest and/or regional function abnormalities are present during exercise-induced myocardial stress. PURPOSE: We addressed the impact of PA on myocardial ischemia and sought to identify signs of exercise-induced myocardial ischemia (assessed by MIBI-SPECT and echocardiography) in patients with PA compared to patients with EH. Patients with consistent signs of myocardial ischemia on all of the tests were studied by coronary arteriography. PATIENTS: We studied 72 patients with PA and an age/sex-matched group of 72 patients with EH enrolled in the cross-sectional Primary Aldosteronism and Heart Italian Multicenter Study (PAHIMS). METHODS: Regional function was detected from echocardiographic measurement of wall motion done at baseline and immediately after exercise. Myocardial perfusion was evaluated by SPECT imaging after injecting 99mTc-MIBI with the same-day protocol using the rest-stress sequence. RESULTS: Although the conditions of arterial pressure, duration of hypertension, and target organ damage were equivalent, the patients with PA had greater incidence of both reversible perfusion defects and abnormalities of regional function. Moreover, multiple regression analysis showed that the high plasma aldosterone level was highly predictive for SPECT ischemic score and wall motion index, suggesting that PA contributes to cardiovascular risk over and above that associated with ventricular hypertrophy. Exercise-induced myocardial ischemia in PA was not segmental but widely distributed suggesting that this phenomenon was not related to abnormal coronary perfusion. Accordingly, of the 38 patients with PA who underwent coronarography, there was no presence of significant coronary atherosclerotic lesions in 30 (78.9%) of the patients. CONCLUSIONS: The PAHIMS observed more exercise-induced moderate myocardial ischemic defects (co-detected by SPECT and echocardiograms and not segmental but widely allocated) in patients with PA than in patients with EH. This phenomenon occurred in a greater percentage of patients with PA without significant coronary lesions (78.95%, n = 38), which supports the possible presence of small-vessel intramyocardial disease.

Adult↗
PubMed1998

Reactions of pyridine coenzyme dimers and monomers with viologens.

DCMV++ (1,1'-dimethyl-2,2'-dicyano-4,4'-bipyridinium, bis-methylsulfate) promotes the aerobic oxidation of the NAD(P) dimers (NADP)2 and (NAD)2 with the formation of 2 mol of NADP+ or NAD+ per mole of dimers. The reaction appears to follow a pseudo-first-order kinetics with respect to the dimer concentration. One mole of oxygen was consumed in the reaction per mole of NAD(P) dimer oxidized and hydrogen peroxide was produced. The monomers NADPH and NADH under the same reaction conditions were not oxidized by DCMV++. In anaerobiosis NAD(P) dimers but not NAD(P)H rapidly reduced DCMV++ to its radical cation DCMV++, which was rapidly back-oxidized by air to its parent dication. Paraquat (MV++) was also able to catalyze the aerobic oxidation of NAD(P) dimers and, at a much lower extent, NADPH and NADH, but only under light irradiation. In anaerobiosis and upon light irradiation all the above nucleotides were able to convert paraquat to its radical cation MV++, reoxidized to MV++ by air admission. This study shows the different ability of NAD(P) dimers and NAD(P)H to undergo one-electron and two-electron oxidation reactions, with different viologens.

Aerobiosis↗