Biomedical subjects

A Biagini

Publications and source records attributed to A Biagini.

At least 19 recordsLinked to original sources

PubMed2003

Kinetics of hydrolysis of fructooligosaccharides in mineral-buffered aqueous solutions: influence of pH and temperature.

High-performance anion exchange chromatography coupled with a pulsed amperometric detection system (HPAEC-PAD) was used to evaluate the extent of chemical hydrolysis of three fructooligosaccharides (FOS) including 1-kestose (beta-D-Fru-(2-->1)(2)-alpha-D-glucopyranoside, GF2), nystose (beta-D-Fru-(2-->1)(3)-alpha-D-glucopyranoside, GF3), and fructofuranosylnystose (beta-D-Fru-(2-->1)(4)-alpha-D-glucopyranoside, GF4). A kinetic study was carried out at 80, 90, 100, 110, and 120 degrees C in aqueous solutions buffered at pH values of 4.0, 7.0, and 9.0. Under each experimental condition, the determination of the respective amounts of reactants and hydrolysis products showed that FOS hydrolysis obeyed pseudo-first-order kinetics as the extent of hydrolysis, which decreased at increasing pH values, increased with temperature. The three oligomers were found to be degraded mainly under acidic conditions, and at the highest temperature value (120 degrees C), a quick and complete acid degradation of each FOS was observed. Using the Arrhenius equation, rate constants, half-life values, and activation energies were calculated and compared with those obtained from sucrose under the same experimental conditions. It appeared that the hydrolysis of FOS took place much more easily at acidic pH than at neutral or basic pH values.

Buffers↗

PubMed2002

Evidence for association of a common variant of the endothelial nitric oxide synthase gene (Glu298-->Asp polymorphism) to the presence, extent, and severity of coronary artery disease.

BACKGROUND: Genetic variants of endothelial nitric oxide synthase (eNOS) could influence individual susceptibility to coronary artery disease. OBJECTIVE: To assess whether Glu298-->Asp polymorphism of the eNOS gene is associated with the occurrence and severity of angiographically defined coronary artery disease in the Italian population. METHODS: Polymerase chain reaction/restriction fragment length polymorphism analysis was done to detect the Glu298-->Asp variant of the eNOS gene in 201 patients with coronary artery disease and 114 controls. The severity of coronary artery disease was expressed by the number of affected vessels and by the Duke scoring system. RESULTS: The frequencies of the eNOS Glu/Glu, Glu/Asp, and Asp/Asp genotypes in the coronary artery disease group were significantly different from those of controls (45.3%, 38.8%, and 15.9% v 42.1%, 51.8%, and 6.1%, respectively; chi2 = 8.589, p = 0.0136). In comparison with subjects who had a Glu298 allele in the eNOS gene, the risk of coronary artery disease was increased among Asp/Asp carriers (odds ratio 2.9, 95% confidence interval 1.2 to 6.8, p = 0.01) and was independent of the other common risk factors (p = 0.04). There was a significant association between the eNOS Glu298-->Asp variant and both the number of stenosed vessels (mean (SEM), 2.3 (0.1) for Asp/Asp v 1.9 (0.1) and 1.8 (0.1) for Glu/Glu and Glu/Asp, respectively; p = 0.01) and the Duke score (56.1 (3.1) for Asp/Asp v 46.7 (2.0) and 46.1 (1.9) for Glu/Glu and Glu/Asp, respectively; p = 0.02). CONCLUSIONS: Glu298-->Asp polymorphism of the eNOS gene appears to be associated with the presence, extent, and severity of angiographically assessed coronary artery disease.

Coronary Artery Disease↗

PubMed2001

Evidence for DNA damage in patients with coronary artery disease.

According to the "monoclonal hypothesis" of atherosclerosis, several studies suggest that cancer and atherosclerosis may have several fundamental biological mechanisms in common. Therefore, an increase in the mutation rate may be involved in the pathogenesis of atherosclerotic plaques. The aim of the study was to verify the presence of chromosomal damage in peripheral blood lymphocytes in patients with coronary artery disease by using micronucleus (MN) test, a reliable biomarker in genetic and cancer risk assessment. Subjects included 53 patients with documented coronary ischemic heart disease (group I); 10 patients with valvular heart disease in absence of atherosclerotic lesions of the coronary arteries (group II) and 16 healthy subjects, age- and sex-matched (group III) were studied as controls. For each subject, two separate cultures were performed and 1000 binucleated cells were scored for the evaluation of MN frequency. The mean (+/-S.E.M.) of MN frequency were 11.9+/-1.7, 5.9+/-1.2 and 3.6+/-0.7 in groups I, II and III, respectively. The MN frequency of group I was significantly higher than that of group III (P=0.02). In group I, MN frequency increased with the number of affected vessels (6.3+/-0.7, 13.9+/-1.6, 14.9+/-5.3 for one-, two-, and three-vessel disease, respectively). Scheffe's test showed that MN frequency was significantly higher in two-vessel compared with one-vessel disease (P=0.0077). Moreover, a positive relationship was found between MN levels and the severity of the disease, calculated by the Duke scoring system (R=0.28, P=0.032), as well as the systolic blood pressure (R=0.34, P=0.009). These results suggest that coronary artery disease in humans is a condition characterized by an increase of DNA damage, positively correlated with the severity of the atherosclerotic disease.

Adult↗

PubMed2001

Evaluation of fructans in various fresh and stewed fruits by high-performance anion-exchange chromatography with pulsed amperometric detection.

Fructans are food-grade non-digestible carbohydrates that exert beneficial nutritional effects. Their characterization and quantification is required for food-labeling purposes. We describe the suitability of high-performance anion-exchange chromatography coupled with pulsed amperometric detection for the identification and quantification of fructans in fresh fruits (various apple and pear cultivars, plum, banana) as well as in commercial stewed fruits obtained from a local manufacturer. After extraction with water and appropriate filtration, inulobiose [beta-D-Fru-(2-->1)-beta-D-fructofuranoside; F2], 1-kestose [beta-D-Fru-(2-->1)2-alpha-D-glucopyranoside; GF2] and nystose [beta-D-Fru-(2-->1)3-alpha-D-glucopyranoside; GF3] were completely separated in a single 36-min run using a Dionex CarboPac PA 100 column and the new quadruple-potential waveform, originally tailored for oligosaccharide separation. No measurable amounts of F3 and GF4 were detected within the group of studied fruit products. Peak identification was realized using standards. The method is easy, reproducible, and sensitive since as little as 28 microg of sugar per gram dry matter can be quantified. Banana and plum are the varieties containing the highest levels of fructans (about 6000 microg per gram dry matter). The maturity of the fruit appears to have a great influence on the level of GF2. Samples of apple-banana stewed fruits contained the highest total fructan concentration (about 700 microg per gram dry matter). Accurate quantification of fructans will allow more precise nutritional formulation and diet selection for higher fructan consumption.

Chromatography, High Pressure Liquid↗

PubMed2001

Separation and identification of enzymatic sucrose hydrolysis products by high-performance anion-exchange chromatography with pulsed amperometric detection.

An accurate carbohydrate analysis method, namely high-performance anion-exchange chromatography with pulsed amperometric detection was successfully applied to the study of sucrose hydrolysis under enzymatic (baker's yeast invertase) conditions. The hydrolysis was monitored by determining sucrose degradation and the corresponding formation of D-glucose, D-fructose and five intermediate fructans using a CarboPac PA-100 (Dionex) analytical anion-exchange column. Highly reproducible results were obtained. The unknown fructans were collected from a semi-preparative CarboPac PA-100 (Dionex) column, neutralized and then desalted on a column containing mixed bed resin AG 501-X8 (D) before identification of the chemical structure. This procedure permitted us to obtain about 20 microg of pure product which is not enough for NMR analysis. Detailed GC-MS analytical data of the methylated compounds indicated that these oligosaccharides were beta-D-Fru-(2 --> 1)-beta-D-Fru-(2 --> 1)-alpha-D-glucopyranoside (1-kestose), beta-D-Fru-(2 --> 6)-alpha-D-glucopyranoside (6-beta fructofuranosylglucose), beta-D-Fru-(2 --> 1)-beta-D-fructofuranoside (inulobiose), beta-D-Fru-(2 --> 6)-beta-D-Fru-(2 --> 1)-alpha-D-glucopyranoside (6-kestose) and beta-D-Fru-(2 --> 6)-alpha-D-Glc-(1 --> 2)-beta-D-fructofuranoside (neokestose) coeluating with a disaccharide.

Chromatography, High Pressure Liquid↗

PubMed2001

Endothelin-1, endothelin-1 receptors and cardiac natriuretic peptides in failing human heart.

Endothelin (ET)-1 is a potent vasoconstrictor peptide produced in the myocardium that can exert important effects on cardiac myocyte growth and phenotype; cardiac natriuretic peptides (ANP and BNP) are known to act as physiological antagonists of ET-1. In this study a comparative determination of ET-1 receptors and of the local productions of ET-1 and of ANP and BNP was made in different sites of failing and nonfailing hearts. Tissue from right and left atrium, right and left ventricle and interventricular septum from seven adult heart transplant recipients with end-stage idiopathic dilated cardiomyopathy (functional class III and IV, with ejection fraction < 35%) and from four postmortem subjects without cardiac complications was analyzed. In failing hearts we observed a tendency to increase of density of binding sites, most evident in left ventricle (62.6+/-22.6 fmol/mg protein vs. 29.0+/-3.3, mean +/- SEM, p = ns). A prevalence of ET-A subclass, observed in all samples, resulted more pronounced in failing hearts where this increase, found in all the cardiac regions, was more evident in left ventricle (p = 0.0007 vs nonfailing hearts). The local concentrations of ET-1, ANP and BNP resulted significantly increased in failing hearts with respect to controls in all sides of the heart. In failing hearts we have observed a tendency to increase in endothelin receptor density mainly due to a significant upregulation of ET-A subtype and a parallel increase of the tissue levels of ANP, BNP and ET-1 indicating an activation of these systems in heart failure.

Adult↗

PubMed2001

Effect of coronary bypass and cardiac valve surgery on systemic endothelial function.

Seventeen patients scheduled for a cardiac procedure necessitating cardiopulmonary bypass underwent serial perioperative assessment of brachial artery flow-mediated dilation. Patients who underwent coronary bypass surgery had a sustained systemic endothelial dysfunction in the perioperative period, whereas those undergoing cardiac valve surgery experienced transient postoperative systemic endothelial dysfunction.

Adult↗

PubMed2001

Application of high performance anion exchange chromatography to study invertase-catalysed hydrolysis of sucrose and formation of intermediate fructan products.

Baker's yeast invertase was found to catalyse transfructosylation reactions in aqueous and anhydrous organic media with sucrose as a substrate, leading to the formation of five intermediate fructans in addition to the release of D-glucose (D-Glc)and D-fructose (D-Fru). All the reaction products were separated and quantitatively estimated using high performance anion exchange-pulsed amperometric detection equipment. The unknown products were subsequently identified by linkage analysis as beta-D-Fru-(2 --> 1)-beta-D-Fru-(2 --> 1)- alpha-D-glucopyranoside (1-kestose), beta-D-Fru- (2 --> 6)-alpha-D-glucopyranoside (6-beta-fructofuranosylglucose), beta-D-Fru-(2 -->1) -beta-D-fructofuranoside (inulobiose), beta-D-Fru-(2 --> 6)-beta-D-Fru-(2 --> 1)-alpha-D-glucopyranoside (6-kestose) and beta-D-Fru-(2 --> 6)-alpha-D-Glc-(1 --> 2)-beta-D-fructofuranoside (neokestose); and this last was eluted together with a disaccharide. The time-course of sucrose hydrolysis via fructan production in 2 ml of a 50 mM sodium acetate buffer (pH 4.5) containing 0.2 M sucrose and 25 U of invertase was different from that in 2 ml of anhydrous toluene with 1.46 M sucrose and 1,000 U of invertase as a suspended powder. Under the latter experimental conditions, invertase was found to exhibit cyclic behaviour, where sucrose was degraded and subsequently synthesised. This observation has not yet been reported, as far as we know.

Biotechnology↗

PubMed2001

Sequence analysis of the aminoacylase-1 family. A new proposed signature for metalloexopeptidases.

The amino acid sequence analysis of the human and porcine aminoacylases-1, the carboxypeptidase S precursor from Saccharomyces cerevisiae, the succinyl-diaminopimelate desuccinylase from Escherichia coli, Haemophilus influenzae and Corynebacterium glutamicum, the acetylornithine deacetylase from Escherichia coli and Dictyostelium discoideum and the carboxypeptidase G(2) precursor from Pseudomonas strain, using the Basic Local Alignment Search Tool (BLAST) and the Position-Specific Iterated BLAST (PSI-BLAST), allowed us to suggest that all these enzymes, which share common functional and biochemical features, belong to the same structural family. The three amino acid blocks which were found to be highly conserved, using the CLUSTAL W program, could be assigned to the catalytic active site, based on the general three-dimensional structure of the carboxypeptidase G(2) from the Pseudomonas strain precursor. Six additional proteins with the same signature have been retrieved after performing two successive PSI-BLAST iterations using the sequence of the conserved motif, namely Lactobacillus delbrueckii aminoacyl-histidine dipeptidase, Streptomyces griseus aminopeptidase, Saccharomyces cerevisiae aminopeptidase Y precursor, two Bacillus stearothermophilus N-carbamyl-L-amino acid amidohydrolases and Pseudomonas sp. hydantoin utilization protein C. The three conserved amino acid motifs corresponded to the following blocks: (i) [S, G, A]-H-x-D-x-V; (ii) G-x-x-D; and (iii) x-E-E. This new sequence signature is clearly different from that commonly reported in the literature for proteins belonging to the ArgE/DapE/CPG2/YscS family.

Amidohydrolases↗

PubMed2001

Up-regulation of 'clearance' receptors in patients with chronic heart failure: a possible explanation for the resistance to biological effects of cardiac natriuretic hormones.

BACKGROUND: Three specific receptors for the cardiac natriuretic peptide system have been identified to date. Down-regulation of the biologically active binding sites (i.e. NPR-A and NPR-B) could explain the blunted response to cardiac natriuretic hormones observed in heart failure (HF), but not the increased metabolic clearance rate. Variations in the ratio between biological and clearance (NPR-C) receptors in target tissue may explain this increase. AIM: The aim of this study was to investigate the regulation of NPR-C receptors on platelets, in patients with HF. METHODS: Eighteen patients with HF (NYHA class: I-II, n=8; III-IV, n=10) and 18 age-matched healthy subjects were studied. The affinity constant (K(d)) and density (B(max)) of binding sites were derived by saturation assays on platelet suspensions using 125I-ANP as radioligand. RESULTS: B(max) increased as a function of the severity of disease: 21.3+/-3.3 fmol/10(9) cells in class III-IV, 11.7+/-2.2 in class I-II, and 11.6+/-1.1 in controls, respectively (P=0.0179 for class III-IV vs. controls and P=0.0451 vs. NYHA I-II). CONCLUSIONS: The increase in density of 'clearance' receptors in severe HF is theoretically consistent with the reduction in cardiac natriuretic peptide biological activity, as well as the increase in metabolic clearance rate. This suggests that clearance receptor blockade may be of potential therapeutic value in HF.

Adult↗

PubMed2001

Differential ability of human endothelial cells to internalize and express exogenous DNA.

Vascular endothelium gene expression regulates blood-vessel wall interactions, vascular permeability, smooth muscle cell growth and tone. The possibility to introduce exogenous DNA or RNA sequences in endothelial cells represents a novel therapeutic approach of vascular disease. The aim of the work was to investigate the ability of endothelial cells to internalize and express exogenous DNA sequences. Human umbilical vein endothelial cells (HUVEC) were transfected with either a 780 bp fluorescein-labeled DNA (FITC-DNA) or pEGFP-C1 plasmid encoding for a green fluorescent protein (GFP), using the cationic liposome DOTAP as transfection reagent. The transfected cell population was passed through a FACScan apparatus and percentage of fluorescent cells was determined using a FACScan analysis programme. The SW620 tumor-derived cell line was used as control. The percentage of FITC-DNA positive cells was 66.0% for HUVEC and 45.0% for SW620 cells. On the contrary, the percentage of GFP-positive cells was 13.8% and 43% for HUVEC and SW620, respectively. By increasing the amount of DNA as well as the protocol of administration the percentage of GFP-positive HUVEC was enhanced suggesting a rapid degradation of DNA in the HUVEC cytoplasm.

Cells, Cultured↗

PubMed2001

Chronic long-term nitrate therapy: possible cytogenetic effect in humans?

Nitrates act as donors of nitric oxide (NO), a molecule with a recognized potential for genotoxicity. In order to assess whether chronic long-term nitrate therapy may increase genotoxicity, we evaluated chromosomal damage in peripheral lymphocytes of 27 ischaemic patients undergoing chronic nitrate treatment for vertical line4 years (7.9 +/- 3.1, mean +/- SD) and 18 age- and sex-matched subjects without any previous nitrate treatment. At the same time, after treatment in vitro with 0-20 microM sodium nitroprusside as NO donor, micronucleus induction and cell proliferation were also evaluated using blood from six different healthy donors. The results showed that the frequency of structural chromosomal aberrations was not significantly higher in the drug-treated group than the control [2.1 +/- 1.4 versus 1.6 +/- 1.2 (mean +/- SD); P = 0.23]. The frequency of micronucleated lymphocytes was higher in the nitrate group than in the control group (6.5 +/- 4.6 versus 3.5 +/- 2.9, P=0.01). In vitro treatment indicated a dose-dependent increase in the frequency of micronucleated lymphocytes with increasing SNP concentrations. Cytotoxicity and cell cycle delay, with a statistically significant difference with respect to control culture, were also observed. Our results suggest a possible genotoxic activity of nitrate therapy. Further studies focusing on the possible link between nitrate therapy and genotoxicity are warranted at this point.

Case-Control Studies↗

PubMed2001

No variation in Hsp70 mRNA level during cardiac surgery in pediatric patients evaluated by semiquantitative RT-PCR.

We evaluated mRNA expression of the heat shock protein gene, Hsp70-1, by means of a semiquantitative RT-PCR in atrial tissue specimens from pediatric patients collected before and after cardiopulmonary bypass surgery for congenital heart diseases, to see whether surgical stress may affect the expression level of this mRNA. We studied thirty nine pediatric patients (aged 3 months to 15 years) undergoing surgical correction of congenital heart malformation. Twenty-one patients were affected by the tetralogy of Fallot, two by combined atrioventricular septal defects, six by ventricular septal defect, three by atrial septal defect, two by atrioventricular canal defect, two by pulmonary valve stenosis, one by mitral insufficiency, and one by double-outlet right ventricle. Our results showed no significant changes in the Hsp70-1 mRNA expression in atrial tissue of patients before and after cross-clamping (the mean relative expression after cross-clamping was 1.0+/-0.6 compared to the baseline value). Furthermore, no significant correlations were observed between cross-clamping time and temperature, cardiopulmonary bypass time and mRNA variation. Our study suggests that, during cardioplegia, myocardial tissue does not have an appropriate adaptive response to surgical stress.

Adolescent↗

PubMed2001

Molecular characterization of chromosome 22 deletions by short tandem repeat polymorphism (STRP) in patients with conotruncal heart defects.

The haploinsufficiency of chromosome 22q11.2 can cause both DiGeorge and velocardiofacial syndromes, both of which are characterized by conotruncal heart defects as well as a wide range of other extracardiac anomalies. Several studies have demonstrated that approximately 10-20% of patients with conotruncal heart defects have a 22q11.2 deletion. In clinical laboratories, the deletion is usually detected by fluorescent in situ hybridization (FISH). We set up a polymerase chain reaction-based non-radioactive method for molecular analysis of the 22q11.2 region in conotruncal cardiac patients with conotruncal defects. Sixty-four children with conotruncal defects and their parents were genotyped by polymerase chain reaction, using fifteen polymorphic markers. We identified nine deletions (confirmed by FISH): eight were "de novo" and one familial, maternally inherited. Six deletions were of paternal and three of maternal origin. There were seven deletions of 3 Mb and the other two were of 1.5 Mb. This method is a cost-effective means of characterizing the 22q11.2 region and it can be applied for a rapid screening of 22q11.2 deletion in patients at risk. In agreement with previously published data, we found no correlation between the sizes and the parental origin of deletions and cardiac or extra-cardiac phenotypes.

Adolescent↗

PubMed2000

Genetic instability and atherosclerosis: can somatic mutations account for the development of cardiovascular diseases?

Several observations suggest that cancer and atherosclerosis may entail fundamentally common biological mechanisms. The accumulation of lipids and the proliferation of smooth muscle cells (SMCs) are the main histological features of sclerotic plaque formation. The most prominent theory concerning the pathophysiological mechanisms of atherosclerotic plaque formation is the "inflammatory response to injury" hypothesis, which states that SMC proliferation is an inflammation-fibroproliferative reaction to different insults to the artery wall. However, recent evidence suggests that alterations at the DNA level may contribute significantly to the development of the disease. In accordance with these findings, the "monoclonal" hypothesis of atherosclerosis has been suggested. This hypothesis proposes that atherosclerosis begins as a mutation or viral infection, transforming a single, isolated smooth muscle cell into the progenitor of a proliferative clone, as seen in carcinogenesis. Studies of DNA damage in atherosclerotic tissues are lacking. Biological evidence for the hypothesis that cancer and atherosclerosis may share pathological mechanisms is discussed, emphasizing the need to perform studies investigating the involvement of somatic mutations in heart diseases.

Animals↗

PubMed2000

Measurement of brain natriuretic peptide in plasma samples and cardiac tissue extracts by means of an immunoradiometric assay method.

We evaluated the analytical characteristics and clinical usefulness of a commercial immunoradiometric assay (IRMA) kit for brain natriuretic peptide (BNP). Mean (+/-SD) plasma BNP concentrations measured in 129 normal subjects were 2.9+/-2.7 pmol/l (median 2.2 pmol/l; range 0.1-12.4 pmol/l). The mean (+/- SD) value observed in healthy men (2.1 +/- 2.0 pmol/l, n = 49) was significantly (p=0.0009) different to that found in women (3.4 +/- 2.9 pmol/l, n=80). A positive relationship (R=0.214, p=0.0174) was found between BNP values and age. In 65 patients with cardiac diseases, BNP levels increased with the progression of clinical severity of disease; patients with more severe disease [NYHA functional class III-IV, mean (+/- SD) BNP +/- 254 +/- 408 pmol/l, n=22] showed significantly (p<0.0001) increased values compared to patients with mild symptoms of disease (NYHA functional class I-II, mean (+/- SD) BNP=19.6 +/- 17.2 pmol/l, n=43). Furthermore, in 32 patients with chronic renal failure, greatly increased (p<0.0001) BNP values were found both before (mean +/- SD=88. 1+/- 111.1 pmol/l) and after haemodialysis (mean +/- SD=65.6 +/- 76.7 pmol/l), with a significant reduction after haemodialysis (p=0.0004) compared to pre-haemodialysis. The mean (+/- SD) BNP value found in atrial extracts collected during aorto-coronary bypass operations in 15 patients was 14.5 +/- 51.9 pmol/g of cardiac tissue. Moreover, the mean (+/- SD) tissue levels of BNP in 7 heart transplant recipients were 128.4 +/- 117.2 pmol/g of cardiac tissue in atrium, 68.4 +/- 76.7 pmol/g in ventricle, and 10.9 +/- 8.5 pmol/g in interventricular septum. Finally, BNP values found in cardiac tissues of two subjects collected at autopsy were considerably lower (on average 1/1000) than those observed in cardiac tissues of patients with cardiac diseases. The IRMA method for BNP determination evaluated in this study showed a good degree of sensitivity, precision and practicability. Therefore, this method should be a reliable tool for the measurement of plasma BNP levels for both experimental studies and routine assay.

Adult↗

PubMed1999

A rapid procedure for the quantitation of natriuretic peptide RNAs by competitive RT-PCR in congenital heart defects.

We report an original application of quantitative reverse transcription-polymerase chain reaction (Q.RT-PCR) for the evaluation of atrial natriuretic factor (ANF), brain natriuretic peptide (BNP) and beta-actin mRNA in small atrial samples (10-15 mg). A fixed amount of total RNA was simultaneously reverse transcribed and amplified with dilutions of a competitor RNA fragment used as a control. We constructed a single synthetic RNA competitor for ANF, BNP and beta-actin. The competitors and targets shared the same primer sequences but yielded PCR products of different sizes. We have investigated ANF, BNP and beta-actin gene expression in patients affected by congenital heart defects (CHD) during the surgical correction of the defect. We collected a right atrial sample from each patient before the start of cardiopulmonary bypass. We studied 14 patients affected by tetralogy of fallot (no. 6), complex CHD (no. 4), and ventricular septal defect (no. 4). The results indicate that the Q.RT-PCR represents a simple, highly specific, non radioactive procedure for the quantification of natriuretic peptide gene expression and is particularly suitable for evaluation of gene expression in small myocardial samples. Our data also suggest that: 1) there is a significant relationship between the levels of ANF, BNP and beta-actin mRNA and the type of CHD; 2) the levels of BNP mRNA are more variable than ANF; 3) the beta-actin seems to be unsuitable for normalising cardiac gene expression in CHD because mRNA basal levels of this protein vary greatly among patients with different type of CHD.

Actins↗

PubMed1999

High density of endothelin binding sites in the hearts of infants and children.

Endothelin (ET)-1 peripheral levels are high in children with respect to values of adults, but its pathophysiological significance remains to be established. In these conditions the interaction of ET-1 with its receptors may constitute a clue to the understanding of ET-1 function. Because a direct determination of ET binding sites in the heart of children is lacking, in this study we have attempted an assessment of the ET receptor status in cardiac tissue of infants (<1 year; 0.39 +/- 0.26 (SD) years, n=6) and children (1-14 years; 6.3 +/- 4.9 years, n=7) as well as an evaluation of the receptor modulation as a function of age, associated to the observed decrease of plasma ET levels between infants and children. ET-1 binding sites have also been evaluated in atrium and ventricle membranes of adult subjects recipient of cardiac transplantation (CHF) and of post-mortem cardiac specimens (autopsy) of non cardiac patients. Considering all the pediatric patients (infants +/- children) studied, an affinity constant (Kd) value of 38.2 +/- 6.1 (SEM) pM and a density (Bmax) value of 166.2 +/- 11.6 fmol/mg protein has been obtained for atrium. Similar values have been found in the ventricle. These values are significantly higher with respect to those obtained in adults: for atrial membranes, Kd = 22.2 +/- 9.7 and 11.6 +/- 1.8 pM; Bmax = 58.4 +/- 22.8 and 42.1 +/- 8.9 fmol/mg protein, respectively in explanted hearts and in post mortem specimens. No significant differences have been found in the binding parameters between infants and children, while, considering our results as a whole, a significant inverse correlation between Bmax and subject age (p<0.001) is suggested. The ET-A/ET-B ratio, evaluated by competition experiments with the specific ET-A antagonist BQ-123, was about 70:30 in pediatric patients, in both atrium and ventricle, without any difference between infants and children. Similar values for ET-A/ET-B ratio in adult CHF patients, in contrast to a reduction (significant only in ventricle) of the percent of ET-A subtype in autopsy, has been found. This is the first study concerning a direct evaluation of ET receptor status in children's hearts; the higher density of binding sites, associated to the elevation of plasma levels, could suggest a enhanced biological function of ET in children.

Adolescent↗