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Biomedical subjects

C Bellini

Publications and source records attributed to C Bellini.

At least 37 records · Page 2Linked to original sources
PubMed1999

Relationship between insulin resistance and nonmodulating hypertension: linkage of metabolic abnormalities and cardiovascular risk.

Insulin resistance is a feature common to patients with diabetes and to some with hypertension. It is assumed that this feature confers the increased metabolic risk in hypertension. However, the state of the renin-angiotensin system might contribute to cardiovascular risk, although there is no clear mechanistic explanation. Our recent observation that insulin levels are increased in a specific subset of patients with normal/high-renin hypertension, the nonmodulators, provided the background for the current hypothesis: to ascertain whether abnormalities in lipid and carbohydrate metabolism are observed in the same patients in whom alterations in sodium transport, sodium homeostasis, and the renin-aniotensin system response have been identified. Exploration of a family history of cardiovascular risk was a secondary goal. Insulin sensitivity (assessed by a 75-g oral glucose load), lipid levels, and two defects in the renin-angiotensin system were assessed in 62 hypertensive and 14 normotensive subjects placed on a high (210 mmol/l) and a low (10 mmol/l) sodium intake for 2 weeks, to classify them as low-renin, nonmodulator, or modulating hypertensive subjects. Only in nonmodulators were the following cardiovascular risk factors significantly increased: fasting insulin (P < 0.01); increment in post-glucose load insulin (P < 0.01); total, LDL, and VLDL cholesterol and triglyceride levels (P < 0.05); and erythrocyte Na+/Li+ countertransport activity (P < 0.001). Both nonmodulators and low-renin hypertensive subjects had a significantly (P < 0.01) increased frequency of a family history of hypertension by questionnaire compared with subjects with intact modulation. However, only nonmodulators had a significantly (P < 0.02) higher frequency of a family history of myocardial infarction. Thus, there is a clustering of metabolic abnormalities in a discrete subset of the essential hypertensive population with a specific dysregulation of the renin-angiotensin system--nonmodulation. The absence of this cluster in low-renin hypertensive subjects may explain their relatively diminished cardiovascular risk. Its presence in nonmodulators likely contributes to the increased cardiovascular risk observed in normal/high-renin hypertension.

Adult↗
PubMed1999

Angiotensin II increases the release of endothelin-1 from human cultured endothelial cells but does not regulate its circulating levels.

We investigated the effect of angiotensin II on endothelin-1 secretion in vitro and in vivo. In vivo, angiotensin II was given intravenously to 23 essential hypertensive and 8 control subjects according to different protocols: Study A, 1.0 ng x min-1 x kg-1 and 3.0 ng x min-1 x kg-1 angiotensin II for 30 min each; Study B, 1.0 ng x min-1 x kg-1 and 3.0 ng x min-1 x kg-1 angiotensin II for 120 min each; Study C, 3.0 ng x min-1 x kg-1 angiotensin II for 30 min followed by a dose increment of 3.0 ng x min-1 x kg-1 every 30 min until mean blood pressure levels increased by 25 mmHg; Study D, 1.0 ng x min-1 x kg-1 followed by 3.0 ng x min-1 x kg-1 angiotensin II for 60 min each on two different NaCl diets (either 20 mmol NaCl/day or 220 mmol NaCl/day, both for 1 week). In all in vivo studies neither plasma nor urine endothelin-1 levels changed with angiotensin II infusion. In contrast, angiotensin II (10(-9), 10(-8), 10(-7) mol/l) stimulated endothelin-1 secretion from cultured human vascular endothelial cells derived from umbilical cord veins in a time- and dose-dependent manner. The in vitro angiotensin II effects were abolished by candesartan cilexetil, an inhibitor of the membrane-bound AT1 receptor, and also by actinomycin D, an RNA synthesis inhibitor, and cycloheximide, a protein synthesis inhibitor, indicating that endothelin-1 release depended on AT1 receptor subtype and de novo protein synthesis. Our findings indicate that angiotensin II regulates endothelin-1 release by cultured endothelial cells through an AT1 receptor-dependent pathway, but does not influence circulating endothelin-1 levels in vivo.

Adult↗
PubMed1998

Altered response to stimuli of the AP-1/DNA binding activity in a syndrome of precocious ageing (geroderma osteodysplastica hereditaria).

Cell senescence produces changes in the expression of specific genes, suggesting that senescent cells express an altered pattern of transcription factors. Here we describe how the DNA binding activity of the activator protein 1(AP-1) complex is altered in the fibroblasts of a geroderma osteodysplastica patient in response to extracellular stimuli.

Aging↗
PubMed1998

AGO1 defines a novel locus of Arabidopsis controlling leaf development.

An allelic series of the novel argonaute mutant (ago1-1 to ago1-6) of the herbaceous plant Arabidopsis thaliana has been isolated. The ago1 mutation pleotropically affects general plant architecture. The apical shoot meristem generates rosette leaves and a single stem, but axillary meristems rarely develop. Rosette leaves lack a leaf blade but still show adaxial/abaxial differentiation. Instead of cauline leaves, filamentous structures without adaxial/abaxial differentiation develop along the stem and an abnormal inflorescence bearing infertile flowers with filamentous organs is produced. Two independent T-DNA insertions into the AGO1 locus led to the isolation of two corresponding genomic sequences as well as a complete cDNA. The AGO1 locus was mapped close to the marker mi291a on chromosome 1. Antisense expression of the cDNA resulted in a partial mutant phenotype. Sense expression caused some transgenic lines to develop goblet-like leaves and petals. The cDNA encodes a putative 115 kDa protein with sequence similarity to translation products of a novel gene family present in nematodes as well as humans. No specific function has been assigned to these genes. Similar proteins are not encoded by the genomes of yeast or bacteria, suggesting that AGO1 belongs to a novel class of genes with a function specific to multicellular organisms.

Amino Acid Sequence↗
PubMed1998

Role of plasma and urinary endothelin-1 in early diabetic and hypertensive nephropathy.

To evaluate the role of circulating and renal endothelin-1 (ET-1) in early diabetic nephropathy, plasma ET-1 levels and urinary ET-1 excretion were evaluated in lean, normotensive patients affected by non-insulin-dependent diabetes (NIDDM) either with (n = 9, NIDDM+) or without microalbuminuria (n = 18, NIDDM-); in never-treated, lean, essential hypertensive patients with (n = 12, EH+) or without microalbuminuria (n = 10, EH-); and in healthy volunteers (n = 12). Results showed higher plasma ET-1 levels in NIDDM+ (1.97 +/- 0.58 pg/mL) than in NIDDM- (1.59 +/- 0.14 pg/mL, P = .013), EH+ (1.40 +/- 0.21 pg/mL, P = .005), EH- (0.91 +/- 0.19 pg/mL, P < .0001), and controls (0.60 +/- 0.10 pg/mL, P < .0001). The circulating ET-1 concentration was also higher in EH+ than EH- and controls (P < .0001). Urinary ET-1 excretion did not differ (P = .387, NS) between NIDDM+ (48.5 +/- 20.1 pg/min) and NIDDM- (40.9 +/- 21.6 pg/min), but was significantly reduced (P < .0001) in both groups compared with controls (70.0 +/- 15.5 pg/min). Similar findings were observed in hypertensive subgroups. No correlations were found between urinary ET-1 and other variables, including plasma ET-1 levels, in all groups. In conclusion, NIDDM+ is accompanied by a significant increase in plasma ET-1 levels. A significant elevation of circulating ET-1 concentration was evident also in NIDDM-, suggesting that early abnormalities of ET-1 production might precede the microalbuminuric phase of diabetes-related renal damage.

Adult↗
PubMed1998

Sur2 mutations of Arabidopsis thaliana define a new locus involved in the control of auxin homeostasis.

A new auxin homeostasis gene in Arabidopsis called SUR2 has been identified. This gene, mapped to the bottom of chromosome 4, is defined by two recessive nuclear mutants designated superroot2 (sur2), which display several abnormalities reminiscent of auxin effects. A number of these characteristics are similar to the phenotype of the previously described auxin-overproducing mutant superroot1 (sur1); however, several lines of evidences reveal that the SUR2 gene defines a new key point in the regulation of endogenous auxin concentrations. The phenotype of the sur1 sur2 double mutant is additive. Analysis by gas chromatography coupled to mass spectrometry indicated increased levels of free indole-3-acetic acid correlated with a decreased level of bound auxin in the sur2 mutant. These results suggest that SUR2 may be involved in the control of auxin conjugation.

Arabidopsis↗
PubMed1998

Higher activity of an aldehyde oxidase in the auxin-overproducing superroot1 mutant of Arabidopsis thaliana.

Aldehyde oxidase (AO; EC 1.2.3.1) activity was measured in seedlings of wild type or an auxin-overproducing mutant, superroot1 (sur1), of Arabidopsis thaliana. Activity staining for AO after native polyacrylamide gel electrophoresis separation of seedling extracts revealed that there were three major bands with AO activity (AO1-3) in wild-type and mutant seedlings. One of them (AO1) had a higher substrate preference for indole-3-aldehyde. This AO activity was significantly higher in sur1 mutant seedlings than in the wild type. The difference in activity was most apparent 7 d after germination, the same time required for the appearance of the remarkable sur1 phenotype, which includes epinastic cotyledons, elongated hypocotyls, and enhanced root development. Higher activity was observed in the root and hypocotyl region of the mutant seedlings. We also assayed the indole-3-acetaldehyde oxidase activity in extracts by high-performance liquid chromatography detection of indole-3-acetic acid (IAA). The activity was about 5 times higher in the extract of the sur1 seedlings, indicating that AO1 also has a substrate preference for abscisic aldehyde. Treatment of the wild-type seedlings with picloram or IAA caused no significant increase in AO1 activity. This result suggested that the higher activity of AO1 in sur1 mutant seedlings was not induced by IAA accumulation and, thus, strongly supports the possible role of AO1 in IAA biosynthesis in Arabidopsis seedlings.

Aldehyde Oxidase↗
PubMed1998

Mutation in the Arabidopsis PASTICCINO1 gene, which encodes a new FK506-binding protein-like protein, has a dramatic effect on plant development.

The pasticcino (pas) mutants of Arabidopsis thaliana are a new class of plant developmental mutants; members of this class show ectopic cell proliferation in cotyledons, extra layers of cells in the hypocotyl, and an abnormal apical meristem. This phenotype is correlated with both cell division and cell elongation defects. There are three complementation groups of pas mutants (pas1, pas2, and pas3, with, respectively 2, 1, and 4 alleles). Here we describe in more detail the pas1-1 allele, which was obtained by insertional mutagenesis. The PAS1 gene has been cloned and characterized; it encodes an immunophilin-like protein similar to the p59 FK506-binding protein (FKBP52). PAS1 is characterized by an FKBP-like domain and three tetratricopeptide repeat units. Although the presence of immunophilins in plants has already been demonstrated, the pas1-1 mutant represents the first inactivation of an FKBP-like gene in plants. PAS1 expression is altered in pas1 mutants and in the pas2 and pas3 mutants. The expression of the PAS1 gene is increased in the presence of cytokinins, a class of phytohormones originally discovered because of their ability to stimulate cell division. These results are of particular relevance as they show for the first time that an FKBP-like protein plays an important role in the control of plant development.

Amino Acid Sequence↗
PubMed1998

Clustering of endothelial markers of vascular damage in human salt-sensitive hypertension: influence of dietary sodium load and depletion.

The contributing role of vascular endothelium in the development of hypertension-related vascular damage is well accepted. Salt-sensitive hypertension is characterized by a cluster of renal, hormonal, and metabolic derangements that might favor the development of cardiovascular and renal damage. To evaluate endothelial involvement in salt-sensitive essential hypertension, plasma levels of several markers of endothelial damage such as endothelin-1 (ET-1), von Willebrand factor (vWf), and soluble (S-) adhesion molecules E-selectin, intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and 24-hour urinary albumin excretion (UAE) were measured in 39 nondiabetic, nonobese, never-treated essential hypertensive patients after intermediate (120 mmol/d), high (220 mmol/d), and low (20 mmol/d) NaCl diets. Patients were classified as salt sensitive (n=18) or salt resistant (n=21) according to their blood pressure responses to changes in dietary NaCl intake. Salt-sensitive hypertensives showed higher plasma ET-1 (P<0.05), vWf (P<0.005), and S-E-selectin levels (P<0.04) and increased UAE (P<0.05) than salt-resistant hypertensives. By contrast, circulating S-ICAM-1 and S-VCAM-1 concentrations were not significantly higher in salt-sensitive (596. 56+/-177.05 ng/mL and 541.06+/-157.84 ng/mL, respectively) than salt-resistant patients (516.86+/-147.99 ng/mL and 449.48+/-158.91 ng/mL, respectively). During the intermediate NaCl diet, plasma ET-1 responses to oral glucose load were greater in salt-sensitive (P<0. 05) than in salt-resistant patients. A marked (P<0.05) hyperinsulinemic response to oral glucose load was evident in salt-sensitive but not salt-resistant patients after each diet. This study shows increased plasma levels of the endothelium-derived substances E-selectin, vWf, and ET-1 in salt-sensitive hypertensives. Our findings support the hypothesis that salt sensitivity is correlated with an increased risk for developing hypertension-related cardiovascular damage.

Adult↗
PubMed1998

The PASTICCINO genes of Arabidopsis thaliana are involved in the control of cell division and differentiation.

The control of cell division by growth regulators is critical to proper plant development. The isolation of single-gene mutants altered in the response to plant hormones should permit the identification of essential genes controlling the growth and development of plants. We have isolated mutants pasticcino belonging to 3 complementation groups (pas1, pas2, pas3) in the progeny of independent ethyl methane sulfonate and T-DNA mutagenized Arabidopsis thaliana plants. The screen was performed in the presence or absence of cytokinin. The mutants isolated were those that showed a significant hypertrophy of their apical parts when grown on cytokinin-containing medium. The pas mutants have altered embryo, leaf and root development. They display uncoordinated cell divisions which are enhanced by cytokinin. Physiological and biochemical analyses show that cytokinins are probably involved in pas phenotypes. The PAS genes have been mapped respectively to chromosomes 3, 5 and 1 and represent new plant genes involved in the control of cell division and plant development.

Adenine↗
PubMed1998

Early activation of vascular endothelium in nonobese, nondiabetic essential hypertensive patients with multiple metabolic abnormalities.

Circulating soluble E-selectin, intercellular adhesion molecule-1 (ICAM-1), and vascular adhesion molecule-1 (VCAM-1) concentrations were evaluated in 93 nonobese essential hypertensive patients, of whom 16 had impaired glucose tolerance and hyperlipidemia (group I); 25 had impaired glucose tolerance (group II); 28 had hyperlipidemia (group III); and 24 had no metabolic abnormalities (group IV). A group of 22 healthy volunteers served as a control group. All groups were without clinical or ultrasound evidence of vascular lesion and were matched for age, sex, and BMI. Endothelial soluble adhesion molecules were measured at baseline, during an oral glucose tolerance test, and after 12 weeks of either enalapril or placebo treatments. Plasma soluble E-selectin, ICAM-1, and VCAM-1 were higher (P < 0.05) in group I and II than in the other groups (group I: E-selectin, 96.1+/-27.1; ICAM-1, 304.0+/-102.1; VCAM-1, 626.1+/-156.2 microg/l. Group II: E-selectin, 88.0+/-18.0; ICAM-1, 268.0+/-84.1; VCAM-1, 594.1+/-140.9 microg/I. Group III: E-selectin, 70.1+/-18.1; ICAM-1, 195.1+/-68.0; VCAM-1, 495.9+/-110.1 microg/l. Group IV: E-selectin, 65.1+/-16.1; ICAM-1, 168.1+/-64.0; VCAM-1, 472.1+/-108.2 microg/l). Soluble adhesins levels were not higher than normal in groups III and IV. Plasma soluble ICAM-1 concentrations increased in group I after glucose administration and were directly correlated with 2-h insulin levels (r=0.648, P=0.007). Compared with placebo, 12 weeks of enalapril treatment significantly (P < 0.0001) reduced soluble E-selectin, ICAM-1, and VCAM-1. Decrements of soluble adhesins were not dependent on enalapril-related blood pressure changes. Therefore, an early endothelial activation was present in essential hypertensive patients with impaired glucose tolerance, regardless of the presence of hyperlipidemia. ACE inhibition counteracted such endothelial activation.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1997

Elevated plasma endothelin-1 levels as an additional risk factor in non-obese essential hypertensive patients with metabolic abnormalities.

Circulating endothelin-1 concentration was evaluated in 93 lean patients with essential hypertension, of whom 16 had impaired glucose tolerance and hyperlipidaemia, 25 had impaired glucose tolerance, 28 had hyperlipidaemia and 24 had no metabolic abnormalities; we also studied 22 control subjects. All groups were age- and sex-matched. Plasma endothelin-1 levels were higher (p < 0.05) in hypertensive patients with impaired glucose tolerance and hyperlipidaemia than in the remaining groups and were directly correlated with fasting insulin levels (r = 0.506, p = 0.045). Therefore, circulating endothelin-1 concentrations are elevated in hypertensive patients with a high-risk profile due to the presence of metabolic abnormalities, and might favour the development of vascular damage.

Cohort Studies↗
PubMed1997

Cristal mutations in Arabidopsis confer a genetically heritable, recessive, hyperhydric phenotype.

A new class of recessive Arabidopsis mutants, designated cristal (cri) has been isolated which display several abnormalities reminiscent of hyperhydric symptoms. These characteristics include translucent and wrinkled cotyledons and leaves, abnormal chloroplast organization, a reduced amount of chlorophyll, a reduced dry weight and a decreased number of palisade cells in the leaves accompanied by an increase of intercellular space, and therefore give a vitreous appearance to the aerial part. The phenotype is also dependent on the culture medium water potential. The cri1 gene was mapped on chromosome 4 close to the DHS1 marker.

Arabidopsis↗
PubMed1997

A comparison of two-dimensional electrophoresis data with phenotypical traits in Arabidopsis leads to the identification of a mutant (cri1) that accumulates cytokinins.

Total proteins extracted from developmental mutants of Arabidopsis thaliana (L.) Heyhn. and from wild-type plants cultivated in the presence of various hormones were analyzed by two-dimensional (2-D) gel electrophoresis. Computer analysis of 2-D gels followed by a statistical treatment of data allowed us to build a phenogram that describes the biochemical distances between the different genotypes. Analysis of the 2-D electrophoresis data allowed us to discriminate mutants in agreement with phenotypical and physiological traits. This biochemical analysis helped us to develop a working hypothesis which led us to show that one developmental mutant (cri1) overaccumulates cytokinins.

Arabidopsis↗
PubMed1997

Endothelin-1 in diabetic and nondiabetic men with erectile dysfunction.

PURPOSE: We evaluated plasma concentration of endothelin-1 in diabetic and nondiabetic men complaining of erectile dysfunction, and the variation of endothelin-1 in cavernous body blood during intracavernous injection of prostaglandin E1. MATERIALS AND METHODS: We evaluated plasma concentrations of endothelin-1 in venous blood of 20 men with erectile dysfunction, 10 with and 10 without diabetes. Plasma concentration of endothelin-1 was also evaluated in the cavernous body blood of the 20 men with erectile dysfunction, during erection induced by intracavernous injection of 10 micrograms prostaglandin E1. A severe vasculogenic component of erectile dysfunction was excluded in all patients. RESULTS: Basal plasma concentration of endothelin-1 in the cubital vein was increased in nondiabetic (1.13 +/- 0.4 pg./ml.) and in diabetic (1.80 +/- 0.2 pg./ml.) patients with erectile dysfunction, compared to control men (0.64 +/- 0.1 pg./ml.) (p < 0.0005 and p < 0.0001, respectively), and in diabetic compared with nondiabetic patients (p < 0.002). No difference and close correlation were observed in the concentration of endothelin-1 in the cavernous body blood evaluated 5 minutes and 30 minutes after injection of prostaglandin E1 (r = 0.89, p < 0.0001, y = 0.98 x + -0.066). The concentration of endothelin-1 in the cavernous body blood evaluated 30 minutes after injection of prostaglandin E1 did not show any difference compared to peripheral venous concentration of the peptide in the 2 patient groups. Concentrations of endothelin-1 in the peripheral vein and the cavernous body blood were not different in patients with a full erection compared with incomplete penis erection after injection of prostaglandin E1 in the cavernous body.

Adult↗