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Biomedical subjects

R Lo Presti

Publications and source records attributed to R Lo Presti.

At least 19 recordsLinked to original sources
PubMed2003

Polymorphonuclear leukocyte integrin pattern, at baseline and after activation, in type 2 diabetic subjects with macrovascular complications.

In vascular atherosclerotic disease and in diabetes mellitus few studies have evaluated the polymorphonuclear leukocyte (PMN) adhesion molecule pattern. In this study we examined the PMN integrin expression at baseline and after activation in controls and type 2 diabetic subjects with macrovascular complications (MVC). We enrolled 21 subjects with type 2 diabetes mellitus and macrovascular complications, localized in peripheral, coronary and cerebral sites. The patients had peripheral occlusive arterial disease, chronic cerebrovascular disease or coronary heart disease. We evaluated the expression of some PMN integrins (CD11a, CD11b, CD11c, CD18), using flow cytofluorimetry, at baseline and after in vitro activation with 4-phorbol-12-myristate-13 acetate. Type 2 diabetic subjects with MVC showed, compared to normals, an increase of CD11a and CD18 and a decrease of CD11b and CD11c. After activation, in PMN(s) of normal subjects, we found an increase in the expression of all adhesion molecules, while in PMNS of type 2 diabetic subjects with MVC we observed an increase of CD11b and CD11c and a decrease of CD11a. In type 2 diabetic patients with MVC the basal upregulation of CD11a and CD18 may be related to the PMN spontaneous activation, while the behavior of CD11b may depend on its self-consumption. After activation the CD11a modification may be due to its cleavage or to an altered integrin phosphorylation/dephosphorylation balance.

Aged↗
PubMed2002

Polymorphonuclear leukocyte membrane fluidity, at baseline and after in vitro activation, in obesity with or without diabetes mellitus.

We studied a group of 28 obese subjects (mean age 38.2+/-13.5 years, body mass index 35.0+/-5.6 kg/m2) with insulin resistance demonstrated employing an euglycemic hyperinsulinemic clamp, subdivided into a subgroup with normal glucose tolerance (NGT) and a subgroup with type 2 diabetes mellitus (DM). We examined the polymorphonuclear leukocyte (PMN) membrane fluidity at baseline and after activation with 4-phorbol 12-myristate 13-acetate (PMA) or N-formyl-methionyl-leucylphenylalanine (fMLP). At baseline, PMN membrane fluidity was significantly decreased in both subgroups compared to normals. In obese subjects with NGT no correlation was found between this PMN determinant and the parameters reflecting the insulin-resistance degree (glucose disposal [M] and metabolic clearance rate of glucose [MCR]), while in type 2 DM subjects the PMN membrane fluidity was correlated to M and MCR. After activation with PMA and fMLP, no variation in PMN membrane fluidity was observed in normals, while in obese subjects with NGT an early decrease was present only after fMLP activation, and in obese subjects with type 2 DM there was a constant and significant decrease of this PMN parameter after activation with PMA and fMLP. Our interest in the study of the PMN membrane fluidity emerges from its known role in PMN function, especially considering that PMN cells, together with monocytes, may be mediators of vascular damage.

Adult↗
PubMed2002

Haemorheological profile in metabolic Syndrome.

Metabolic Syndrome (MetS) has been defined as a clinical condition including impaired glucose tolerance or diabetes mellitus and/or insulin-resistance, associated with two or more of the following components: arterial hypertension, central obesity, dyslipidaemia, microalbuminuria. In a group of subjects with MetS we examined the macrohaemorheological profile, demonstrating a significant increase of blood, plasma and serum viscosity and a decrease of whole blood filterability. The results show that in these subjects a secondary hyperviscosity condition is present, but also that several significant correlations are present between the haemorheological variables and some aspects of MetS, especially those reflecting central obesity (waist to hip ratio) and insulin-resistance. The altered haemorheological profile likely contributes to explain the high cardiovascular risk present in MetS, but it may also participate, through its influence on haemodynamic pattern, in the pathogenesis of insulin-resistance.

Adult↗
PubMed2002

Polymorphonuclear leukocyte integrin profile in diabetes mellitus.

We examined the polymorphonuclear leukocyte (PMN) integrin pattern in 45 diabetic subjects without macrovascular complications, including 21 subjects with type 1 and 24 with type 2 diabetes mellitus. The PMN adhesion molecules (CD11a, CD11b, CD11c, CD18) were evaluated using indirect immunofluorescence and a flow cytometer, at baseline and after in vitro activation with 4-phorbol 12-myristate 13-acetate (PMA) and N-formyl-methionyl-leucyl-phenyl-alanine (fMLP). At baseline, in diabetic subjects the phenotypical expression of CD11a and CD11b was significantly reduced and CD11c was increased, whereas CD18 was unchanged in comparison with normals. Considering type 1 and 2 diabetic subjects separately, CD11a was reduced and CD11c was increased in both subgroups, CD11b was decreased only in type 1 diabetics and CD18, decreased in type 1, was increased in type 2 subjects. After activation with PMA and fMLP, in normal subjects we observed a significant increase of all PMN adhesion molecules whereas in diabetic subjects only CD11c increased significantly with both activating agents, and CD11b increased only after PMA activation. In type 1 diabetic subjects only CD11c expression was increased, and in type 2 diabetic subjects an increase of CD11b (with PMA) and an increase of CD11c (with fMLP) were noted. In conclusion, we found in diabetic subjects of type 1 and 2 an altered behaviour pattern of PMN integrins both at baseline and, in particular, after in vitro activation. These data may help in explaining the role of PMN in the evolution of diabetic vascular complications.

Adult↗
PubMed2001

Granulocyte integrins before and after activation in acute ischaemic stroke.

We examined in 19 subjects with acute ischaemic stroke (AIS) the PMN integrin pattern (CD11a, CD11b, CD11c, CD18), using indirect immunofluorescence and adopting a flow cytometer, at baseline and during activation, prolonged for 5 and 15 min, with 4-phorbol 12-myristate 13-acetate (PMA). At baseline, an increase in the expression of CD11c and CD18 and a decrease in the CD11b were evident in AIS subjects compared to normals. After activation, we found in normals a constant and significant increase of all PMN adhesive molecules, while in AIS subjects, we found an increase in CD11b and CD18, a decrease in CD11a and no variation in CD11c. While the basal upregulation of CD11c and CD18 may depend on the PMN spontaneous activation or on the increase of cytokines, the decrease of CD11b may be due to its self-consumption. After activation, the decrease in CD11a noted in AIS may be related to its cleavage or to an altered integrin phosphorylation/dephosphorylation balance.

Acute Disease↗
PubMed2000

Polymorphonuclear leukocyte membrane fluidity before and after activation in subjects with insulin resistance.

The aim of this research was the evaluation of polymorphonuclear leukocyte (PMN) membrane fluidity in subjects with insulin resistance. Insulin sensitivity, in fact, may be influenced by plasma membrane fluidity. We enrolled 19 subjects with insulin resistance previously demonstrated during an euglycemic hyperinsulinemic clamp. PMN membrane fluidity was studied by labeling intact cells with the fluorescent probe 1-[4-(trimethylamino)phenyl]-6-phenyl-1,3,5-hexatriene and calculating the fluorescence polarization degree. The measurement was made before and after incubation of PMNs with two activating agents: 4-phorbol 12-myristate 13-acetate (PMA) and N-formyl-methionyl-leucyl-phenylalanine (fMLP). The baseline data showed a reduction of PMN membrane fluidity in subjects with insulin resistance. After PMN activation with PMA and fMLP, no significant variation in membrane fluidity was present in PMNs from normals, while in those from subjects with insulin resistance a slight decrease in PMN membrane fluidity was found only after activation with fMLP. The behavior of PMN membrane fluidity, before and after activation, distinguishes insulin-resistant subjects from normal controls, although the effect cannot be directly correlated with the degree of insulin resistance.

Adolescent↗
PubMed1999

Changes in somatosensory evoked potentials following forebrain ischemia in the gerbils: effects of felbamate.

Somatosensory evoked potentials (SEPs) as well as change following transient cerebral ischemia in the gerbil were characterized in this study. SEPs were measured in each gerbil before ischemia (day -1), during ischemia, 10 min, 2, 4, 8, 24, 48 h and 8 days after recirculation. During bilateral carotid occlusion, SEP amplitude was dramatically reduced and central conduction time was significantly increased. During recirculation these values showed an improvement when compared to ischemic but not to control values. Moreover at 8 days of recirculation they were still statistically different from control values. Felbamate administration at the dose of 150 mg kg(-1), immediately after recirculation was shown to ameliorate neurophysiological recovery following cerebral ischemia.

Animals↗
PubMed1999

Chronic renal failure: leukocyte rheology and polymorphonuclear cytosolic Ca2+ concentration.

In a group of subjects with chronic renal failure (CRF), we evaluated the leukocyte rheological activity, expressed as the filtration rate, the polymorphonuclear (PMN) membrane fluidity and the PMN cytosolic Ca2+ content. Using the St. George's Filtrometer, we determined the filtration rate of unfractionated, mononuclear and PMN leukocytes. Using the fluorescent probe 1.4-(trimethylamino)-phenyl-4-phenyl-hexatriene (TMA-DPH), we examined the PMN membrane fluidity and, using the Fura 2-AM, the PMN cytosolic Ca2+ content. From the results obtained, it is evident that only the initial relative flow rate of unfractionated leukocytes was significantly reduced in subjects with CRF, while the filtration parameters of mononuclear and PMN cells did not distinguish normals from CRF subjects. No variation was evident for the PMN membrane fluidity, while the PMN cytosolic Ca2+ content was significantly increased in CRF subjects. In these subjects no correlation was found between leukocyte filtration parameters, PMN membrane fluidity, PMN cytosolic Ca2+ content and plasma parameters (blood urea nitrogen and serum creatinine), reflecting the degree of the CRF. In conclusion, in CRF subjects the abnormality of the leukocyte flow properties was restricted to the initial flow rate of unfractionated leukocytes, whereas the increase of PMN cytosolic Ca2+ content might be attributed to PMN activation.

Calcium↗
PubMed1999

Haemorheological profile in subjects with nonvalvular atrial fibrillation.

In a group of subjects (n = 35) with nonvalvular atrial fibrillation (AF) subdivided according to the presence (n = 16) or absence (n = 19) of left atrial spontaneous echocontrast (SEC), demonstrated using transthoracic and transesophageal echocardiography, we evaluated the principal haemorheological determinants: whole-blood viscosity, plasma and serum viscosity, haematocrit, whole-blood filtration (VBC) and mean erythrocyte aggregation (MEA). From the obtained data it was evident that in subjects with nonvalvular AF there was an impairment of the haemorheological profile that seemed more evident in AF subjects with SEC, although no significant haemorheological difference was present between AF subjects with and without SEC. These findings need to be underlined considering that this clinical condition is associated to a major thromboembolic risk.

Aged↗