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Biomedical subjects

R Lo Presti

Publications and source records attributed to R Lo Presti.

At least 55 records · Page 3Linked to original sources
PubMed1998

Essential hypertension: leukocyte rheology and polymorphonuclear cytosolic Ca2+ content at baseline and after activation.

In 24 hypertensives we evaluated, at baseline, the leukocyte filtration parameters (using the St. George's Filtrometer), polymorphonuclear (PMN) membrane fluidity (with the fluorescent probe 1-[4-(trimethylamino)phenyl]-6-phenyl-1,3,5-hexatriene [TMA-DPH]) and PMN cytosolic Ca2+ content (with the fluorescent probe Fura 2-AM). In a subgroup of hypertensives (n = 17) the PMN filtration parameters, PMN membrane fluidity and cytosolic Ca2+ content were evaluated after in vitro chemotactic activation (prolonged for 5 and 15 min) with two stimulating agents (4-phorbol 12-myristate 13-acetate [PMA] and N-formyl-methionyl-leucyl-phenylalanine [fMLP]). It was evident, from the baseline data, that there was a significant difference in the mononuclear (MN) initial relative flow rate (IRFR), clogging rate (CR) and clogging particles (CP), and in PMN cytosolic Ca2+ content. There were, however, no differences in the filtration parameters of unfractionated leukocytes and PMNs or in PMN membrane fluidity. After activation, in normals and in hypertensives, a significant variation in PMN filtration parameters was evident. In normals no variation was present in PMN membrane fluidity or cytosolic Ca2+ content after activation. In hypertensives, however, we found an increase solely in PMN cytosolic Ca2+ content after fMLP activation. After PMN activation (at 15 min) one parameter (IRFR) of PMN filtration distinguished normal subjects from hypertensives. No difference between the two groups was found in PMN membrane fluidity or PMN cytosolic Ca2+ content after PMN activation.

Adult↗
PubMed1997

Leukocyte flow properties, polymorphonuclear membrane fluidity and cytosolic Ca2+ content in subjects with vascular atherosclerotic disease.

In a group of subjects with monovascular atherosclerotic disease (MVAD) and in a group of subjects with polyvascular atherosclerotic disease (PVAD) we evaluated white blood cell (WBC) filtration (unfractionated, mononuclear -MN-, polymorphonuclear -PMN- cells), using the St. George Filtrometer and considering respectively the initial relative flow rate (IRFR) and the clogging rate (CR), the polymorphonuclear leukocyte membrane fluidity, employing the fluorescent probe 1.4-(trimethylamino)-phenyl-4-phenylhexatriene (TMA-DPH) and calculating the fluorescence polarization degree, and the polymorphonuclear leukocyte cytosolic Ca2+ content, adopting the fluorescent probe Fura 2-AM. Only the filtration parameters (IRFR, CR) of unfractionated WBCs discriminate normals from MVAD and PVAD subjects, and also monovascular and polyvascular VAD subjects between them. The filtration parameters of mononuclear and polymorphonuclear leukocytes do not distinguish normals from MVAD and PVAD subjects. PMN membrane fluidity does not differentiate normals from MVAD and PVAD subjects, while PMN cytosolic Ca2+ content discriminates normals from MVAD and PVAD subjects, but does not distinguish the two groups of VAD subjects. In conclusion, in subjects with vascular atherosclerotic disease we noted an alteration of the unfractionated leukocyte flow properties, more evident in PVAD subjects, and an increase of the PMN cytosolic Ca2+ content.

Aged↗
PubMed1995

Platelet membrane fluidity and platelet membrane lipid pattern in essential hypertension.

In a group of subjects with essential hypertension platelets were studied in resting conditions: platelet membrane fluidity was measured with the fluorescent probe 1.4-(trimethylamino)-phenyl-4-phenylhexatriene (TMA-DPH), platelet membrane cholesterol/phospholipid ratio was evaluated separating the membrane lipids with column chromatography, and platelet membrane individual phospholipids were determined using two-dimensional thin-layer chromatography. From the obtained results, it is evident that platelet membrane fluidity does not differentiate normals from hypertensives; platelet membrane cholesterol/phospholipid ratio is increased in hypertensives, while of the platelet membrane individual phospholipids, only the phosphatidylcholine is increased. In normals and hypertensives, no relation is evident between platelet membrane fluidity, platelet membrane lipid pattern, and systolic and diastolic blood pressure values.

Adult↗
PubMed1995

Cytosolic Ca2+ content and membrane fluidity of platelets and polymorphonuclear leucocytes in diabetes mellitus.

Considering the role played by platelets and leucocytes in diabetic disease and keeping in mind the strong correlation between functional and metabolic aspects that characterizes this clinical condition, we evaluated, in two groups of diabetics, respectively the platelet and polymorphonuclear (PMN) cytosolic Ca2+ content (employing the fluorescent probe Fura 2-AM) and membrane fluidity (using the fluorescent probe TMA-DPH and considering the fluorescence polarization degree, inversely related to the membrane fluidity). From the obtained results, it is evident that the platelet cytosolic Ca2+ content does not distinguish normals from diabetics of type 1 and 2; the platelet membrane fluidity instead does not discriminate normals from diabetics, but differentiates diabetics of type 1 and 2 (type 1 = 0.284 +/- 0.015; type 2 = 0.314 +/- 0.018; p < 0.001). PMN cytosolic Ca2+ content and membrane fluidity do not discriminate normals from diabetics. In the two groups of diabetics none of the platelet and PMN parameters (cytosolic Ca2+ content and membrane fluidity) are related to the glycometabolic pattern.

Adolescent↗
PubMed1995

Membrane fluidity, membrane lipid pattern, and cytosolic Ca2+ content in platelets from a group of type II diabetic patients with macrovascular complications.

OBJECTIVE: To evaluate platelet membrane fluidity and some platelet metabolic parameters in type II diabetic patients with macrovascular complications. RESEARCH DESIGN AND METHODS: In a group of 21 type II diabetic patients with macrovascular complications, we evaluated platelet membrane fluidity [marking intact resting platelets with the fluorescent probe 1,4-(trimethylamino)-phenyl-4-phenylhexatriene (TMA-DPH)], platelet membrane lipid pattern (cholesterol:phospholipid [C:PL] ratio and individual phospholipids), and platelet cytosolic Ca2+ content (marking intact resting platelets with the fluorescent probe Fura 2AM). RESULTS: Platelet membrane fluidity is decreased in type II diabetic patients with macrovascular complications compared with normal subjects (P < 0.001). Platelet membrane C:PL ratio and cytosolic Ca2+ content do not discriminate normal subjects from diabetic patients, and for individual phospholipids, only phosphatidylethanolamine is decreased in diabetic patients compared with control subjects (P = 0.051). In normal subjects, the polarization degree of TMA-DPH is related to phosphatidylserine (P < 0.05) and phosphatidylcholine (P < 0.05), and in diabetic patients the polarization degree of TMA-DPH is related to C:PL ratio (P < 0.05) and sphyngomyelin (P < 0.05). CONCLUSIONS: In type II diabetic patients with macrovascular complications, we observed an abnormality of platelet membrane fluidity, which may contribute to platelet functional alteration present in this clinical condition.

Aged↗
PubMed1995

[Plasma, erythrocyte and platelet magnesium in essential hyperTension, diabetes mellitus without and with macrovascular complications and atherosclerotic vascular disease].

In 4 groups of subjects with different clinical conditions: essential hypertension, diabetes mellitus without and with macrovascular complications, vascular atherosclerotic disease (VAD), we evaluated the plasma, erythrocyte and platelet magnesium content, the correlations between them and the relationships among all these parameters and metabolic and haemodynamic determinants. From the obtained data, it is evident that platelet magnesium content is decreased in hypertensives and in type 2 diabetics with macrovascular complications, and in subjects with VAD, while the red cell magnesium content in VAD subjects and in type 2 diabetics with macrovascular complications is increased; in type 1 diabetics we observed a decrease of the plasma magnesium level. The relationships between the plasma and cellular magnesium content, in the different clinical conditions, seem interesting.

Adult↗
PubMed1993

[Pathogenesis of diabetic microangiopathy].

Several are the recent experimental data regarding the pathogenesis of diabetic microangiopathy, even if the comprehensive picture of this condition is still rather incomplete. The functional and structural alterations of several organs involved (first of all kidney and retina) are especially dependent on the activation of the polyol pathway and on the increase of the nonenzymatic glycosylation. An important determinant of diabetic microangiopathy is the increase of permeability, at first charged especially to the haemodynamic alterations and partly reversible, and later supported by irreversible variations of the cellular and extracellular components of the vascular wall. Genetic factors certainly contribute to the explanation of the diverse gravity of microvascular damage in diabetic patients, even if the mechanisms by which they interfere are only partly known. Furthermore, the links between arterial hypertension and diabetic nephropathy, and also the reduction in glycosaminoglycans in the basal membranes are perhaps genetically originated.

Animals↗
PubMed1992

Red cell membrane protein lateral mobility in diabetes mellitus.

In a group of 24 diabetics subdivided for type, we evaluated the red cell membrane protein lateral mobility marking intact red cells with pyrene-3-maleimide (3-PM) and calculating the dimer to monomer fluorescence intensity ratio (Iex/Im). The same fluorescent parameter was determined in a group of 13 normal controls. From the obtained data, it is evident that the red cell membrane protein lateral mobility clearly discriminates normals from diabetics of type 1 and 2. In normals and in diabetics of type 1 and 2 no relationship is present between this fluorescent determinant and the glycometabolic parameters (FBGL and HbA1c); considering all the diabetics, a negative relationship is evident between Iex/Im ratio and HbA1c only.

Adolescent↗
PubMed1991

[Physiopathological aspects of secondary hyperuricemia].

Secondary hyperuricaemia expresses a heterogeneous group of clinical conditions generally classified according to the pathogenetic criteria. Hyperuricaemia can depend on an increased production, reduced renal excretion or on the combination of both. Myelo and lymphoproliferative diseases are clinically prevalent among the conditions accompanying this overproduction. The most frequent causes of reduced uric acid excretion are chronic renal failure and diuretic treatment. In recent years, several conditions of hyperuricaemia with mixed pathogenesis have revealed a common mechanism connected to the ATP cellular depletion.

Acute Disease↗
PubMed1991

Red cell membrane dynamic properties and erythrocyte metabolic parameters in essential hypertension: preliminary report.

In a group of 12 subjects with essential hypertension (EH), we evaluated the erythrocyte membrane fluidity and red cell membrane transverse fluidity gradient. We also evaluated the total red cell Ca content, the red cell cytosolic free calcium, the red cell membrane cholesterol/phospholipid ratio and the red cell membrane individual phospholipids. From the data obtained, it is evident that the erythrocyte membrane fluidity and red cell membrane transverse fluidity gradient discriminate normals from hypertensives. None of the red cell metabolic parameters is able, however, to differentiate normals from hypertensive subjects. Our data underline the abnormality of the red cell membrane dynamic properties in hypertension; this abnormality is not, however, related to the red cell metabolic parameters considered.

Adult↗
PubMed1991

Total red cell calcium content, cytosolic red cell free calcium and erythrocyte membrane dynamic properties in diabetes mellitus.

In a group of diabetics subdivided for type (12 of type 1 and 12 of type 2), we evaluated the total red cell Ca content, red cell cytosolic free calcium, erythrocyte membrane fluidity and erythrocyte membrane protein lateral mobility. From the results obtained, it is evident that the total red cell Ca content does not discriminate normals from type 1 and 2 diabetics, whereas the red cell cytosolic free calcium does differentiate between these diabetic types. Erythrocyte membrane fluidity and erythrocyte protein lateral mobility discriminate normals from type 1 and 2 diabetics. In normals and in diabetics of type 1 and 2, no relationship is evident between total red cell Ca content, membrane fluidity and membrane protein lateral mobility. A slight, but significant negative correlation between red cell cytosolic free calcium values and parameters reflecting the red cell dynamic properties is present in type 2 diabetics only.

Adolescent↗
PubMed1991

Rheological determinants and red cell lipidic pattern in essential obesity, in obese subjects with non-insulin-dependent diabetes mellitus (NIDDM) and in obese subjects with impaired glucose tolerance (IGT).

In a group of subjects with essential obesity, in a group of obese subjects with non-insulin dependent diabetes mellitus (NIDDM), and in a group of obese subjects with impaired glucose tolerance (IGT), we evaluated whole-blood filtration, mean erythrocyte aggregation, erythrocyte membrane fluidity and red cell lipid pattern. From these data, it is evident that the macro- and microrheological determinants are able to discriminate normals from each group of obese subjects. Regarding the red cell lipids, few are the variations between each group of obese subjects and normal controls.

Adult↗
PubMed1990

Total red cell Ca2+ content and rheological determinants in a group of subjects with vascular atherosclerotic disease.

We evaluated the total red cell Ca2+ content and the macro- and microrheological determinants in a group of subjects with vascular atherosclerotic disease (VAD). From the results obtained it is evident that, compared to controls, the VAD group presents an alteration of the macro- and microrheological parameters. No difference is evident for the red cell Ca2+ content in normals and in VAD subjects. No relationship is present between total red cell Ca2+ content, VBC (volume blood cells), MEA (mean erythrocyte aggregation) and red cell membrane fluidity expressed as Iex/Im ratio. In contrast to the latter, are the correlation between the red cell Ca2+ content and the degree of polarization obtained with fatty acid probes.

Aged↗