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B Zappacosta

Publications and source records attributed to B Zappacosta.

50 records · Page 3Linked to original sources
PubMed1987

Cardiovascular reactivity, plasma markers of endothelial and platelet activity and plasma renin activity after mental stress in normals and hypertensives.

Endothelial injury and platelet activation, mechanisms known to be involved in vascular lesions, may promote the development of cardiovascular disorders possibly associated with mental stress. Plasma markers of platelet activation (beta-thromboglobulin, BTG) and of endothelium activity (factor VIII/von Willebrand factor, FVIII/vWf) and plasma renin activity (PRA) were determined in 17 healthy normotensive volunteers and in 21 hypertensives without target-organ damage before and after mental stress (a colour-word conflict test). The aim of the study was to compare cardiovascular reactivity with the stress-induced changes in platelet and endothelium activity. Individual responses in BTG and factor FVIII/vWf after the colour-word conflict test were markedly different, but significant mean increases were observed in both groups with no difference in the degree of response and in the percentage of responders. No correlations were found among the changes in plasma variables or between cardiovascular reactivity (systolic and diastolic blood pressure and heart rate) and the changes in BTG, FVIII/vWf and PRA. These findings suggest that hypertensive patients do not have an abnormal platelet or endothelium reactivity to mental stress, at least when the disease is free of vascular complications. This dissociation of stress-induced variability in BTG and FVIII/vWf and cardiovascular reactivity indicates that these indices could be used as independent markers of mental stress.

Adult↗
PubMed1986

Urine beta-thromboglobulin concentration or beta-thromboglobulin/creatinine ratio in single voided urine samples cannot be reliably used to estimate quantitative beta-thromboglobulin excretion.

Different procedures are currently used in the urine beta-thromboglobulin (BTG) assay. We investigated the reliability of limited urine collections and of different expressions of urine BTG results (concentration, urine BTG/creatinine ratio) for the measurement of hourly or daily BTG excretion rates. BTG was measured by a sensitive RIA method in various urine collections of normal subjects (n.80) and patients (n.120) with miscellaneous diseases where an enhanced in-vivo platelet activation could be expected. The BTG concentration in a 6-hour urine collection appeared to change in relation to the urine flow rate (r = -0.53 in normals, r = 0.27 in patients, p less than 0.01) and urine osmolality (r = 0.46 in normals, r = 0.31 in patients, p less than 0.01). In both normals and patients not a very good correlation was observed between the urine BTG/creatinine ratio and the BTG excretion rate (r = 0.54 and r = 0.48; p less than 0.001, respectively). Variable coefficients of correlation (r = 0.83-0.34) were observed between the BTG excretion rate of single voidings of the morning, afternoon-evening and night and the daily BTG excretion both in normals and patients. Reliable measurements of the BTG in urine should be expressed as the hourly excretion rate in a given period of the day for limited urine collections or as the daily excretion for 24-hour urine collections.

Beta-Globulins↗
PubMed1986

Abnormal diurnal changes in in-vivo platelet activation in patients with atherosclerotic diseases.

We measured the urinary excretion of beta-thromboglobulin in timed urine samples collected by 2 groups of healthy volunteers, (group I, n = 20, mean age 34 years, group II, n = 15, mean age 64 years) and by patients (n = 40) with symptomatic atherosclerotic diseases. Older healthy subjects were found to excrete high amounts of BTG in comparison to young subjects (302.25 +/- 50.61 vs 219.65 +/- 59.31 ng/day, P less than 0.05). Higher (P less than 0.01) levels of urinary BTG were observed in patients with coronary (427.61 +/- 179.96 ng/day), cerebral (422.13 +/- 223.2 ng/day) and peripheral (454.16 +/- 269.05 ng/day) arterial diseases and in diabetic patients with diffuse vascular complications (613.71 +/- 253.07 ng/day). The diurnal variability of BTG excretion, measured as coefficient of variation (C.V. %) of the mean daily excretion rate, was higher (P less than 0.001) in atherosclerotic patients (70.59 +/- 26.57) as compared with the similar values observed in the control groups of young (32.05 +/- 14.54) and older subjects (26.38 +/- 8.4). Comparable diurnal variabilities of the creatinine excretion rate were observed in the control groups and in patients. These data indicated that in vivo platelet activation may occur in atherosclerotic patients with a distinctive high fluctuation rate.

Adult↗
PubMed1984

Long-term retrospective control procedures for monitoring analytical performance of laboratory instruments.

We propose a statistical procedure for long-term quality-control of laboratory instruments, including daily, day-to-day, and monthly evaluations. The procedure is based on the unique and unequivocal interpretation of five results for control sera by calculation of a Reliability Index and further manipulations of this unitless parameter. This method, which we have tested during the past two years, allows for monitoring analytical performance and making comparisons with results of interlaboratory surveys. The monthly analytical variability, expressed as "total error," is an indicator of the clinical usefulness of analytical results.

Autoanalysis↗
PubMed1983

Laboratory control of urokinase therapy at low or moderate dosages. An in-vitro study.

In vitro thrombolytic experiments were performed in a system composed of a radioactive clot (125I fibrinogen) perfused by whole anticoagulated blood to which a small amount of urokinase (UK) was added by continuous infusion. At various intervals a small aliquot of blood was drawn from the system and assayed for fibrinogen, plasminogen and alpha 2-antiplasmin. Results were correlated with the degree of thrombolysis measured continuously as decrease of clot radioactivity by a ratemeter connected to a recorder. The coefficients of correlation between fibrinogen, plasminogen and thrombolysis were -0.45 and -0.46, respectively (p less than 0.001). The highest coefficient of correlation was observed between alpha 2-antiplasmin change and thrombolysis (-0.84; p less than 0.001). Results indicate that the initiation of an effective thrombolytic state induced by UK required the depletion of about 50% of alpha 2-antiplasmin. The measurement of alpha 2-antiplasmin during UK therapy at low or moderate dosage appears to be useful for dosage adjustments leading to the development of a thrombolytic state.

Blood Coagulation Tests↗
PubMed1983

[Assay of the thromborheological properties of blood by measurement of the filtration pressure of normal blood across polycarbonate filters].

A simple test for the evaluation of the thromborheological properties of native blood was developed. The test measured the filtration pressure produced by the 24-sec passage of 1.5 ml of native blood through a polycarbonate filter with pores of 5 mu. Healthy subjects, patients with symptomatic atherosclerosis and patients with miscellaneous non-vascular disorders taking neither drugs active on red blood cell deformability nor on platelet and hemostatic functions were examined by this test. No correlations between filtration pressure of native blood and fibrinogen, PTT, factor VIIIR:Ag and hematocrit values were found. The results suggest that this test may be useful in the detection of thrombophilic patients and in monitoring the effectiveness of drugs known to be active on red blood cell deformability and/or on platelet and hemostatic functions.

Arteriosclerosis↗
PubMedDate not supplied

Effect of aqueous extract of cigarette smoke on peripheral blood polymorphonuclear leukocytes chemiluminescence.

Cigarette smoke induces a vast cohort of deleterious effects on biological structures. In the present paper, the effect of aqueous extract of cigarette smoke on the activity of polymorphonuclear leukocytes was studied. Although the aqueous extract of cigarette smoke inhibits the luminol oxidation catalysed by horseradish peroxidase, it strongly interacts with polymorphonuclear leukocytes and inhibits their phorbol-induced chemiluminescence in the presence of either luminol or lucigenin. The results indicate that at least some of the components of the aqueous extract of cigarette smoke may strongly interfere with polymorphonuclear cells, contributing to the deleterious effects of smoke products.

Acridines↗
PubMedDate not supplied

Effect of homocysteine on polymorphonuclear leukocyte activity and luminol-dependent chemiluminescence.

Homocysteine is a non-protein-forming sulphur amino acid that plays an important role in remethylation and trans-sulphuration processes. In recent years, a high plasma homocysteine concentration has been implied as a possible pathophysiological factor in atherosclerosis and artery and deep vein thrombosis, probably through generation of H(2)O(2), enhanced platelet activity and increased production of macrophage-derived tissue factor. Furthermore, an increase of polymorphonuclear leukocyte (PMN) activity mediated by homocysteine-generated H(2)O(2) has also been reported. Because some preliminary experimental results in our laboratory did not confirm this effect of homocysteine on PMNs, we investigated the effect of homocysteine on the activity of PMNs, measured by their luminol-dependent chemiluminescence. Moreover, we also studied the effect of homocysteine in a luminol-hypochlorite chemiluminescent system. Our results clearly indicate that homocysteine at micromol/L concentrations (10-100 micromol/L) slightly inhibits neutrophil chemiluminescence, while it strongly inhibits the luminescence of the luminol-hypochlorite system. Therefore, the hypothesis that homocysteine induces an increase of H(2)O(2)-mediated neutrophil activity is not supported and, probably, the common opinion that views the H(2)O(2) generated by homocysteine as a possible mechanism for cardiovascular damage should be reconsidered.

Homocysteine↗
PubMedDate not supplied

Effect of aqueous cigarette smoke extract on the chemiluminescence kinetics of polymorphonuclear leukocytes and on their glycolytic and phagocytic activity.

Water-soluble extracts of cigarette smoke are easily formed in some body compartments, such as saliva or fluid lining alveolar spaces, and can act on both cellular and extracellular compartments. In this paper we have analysed the effect of aqueous smoke extract on some metabolic and functional aspects of polymorphonuclear leukocytes. In particular, the following cellular aspects were studied: chemiluminescence, glycolysis, membrane fluidity and microscopic interaction with zymosan particles. While chemiluminescence and glycolytic activity are highly inhibited, no effect of smoke extract on membrane fluidity was observed. Moreover, the response of luminol-dependent chemiluminescence was significantly delayed, while that of lucigenin-dependent chemiluminescence was anticipated. Furthermore, the phagocytic ability of neutrophils pretreated with aqueous smoke extract was also significantly hindered. All these results might indicate that the finely tuned activity of polymorphonuclear leukocytes is somehow hampered by the aqueous extract of cigarette smoke in a way which makes these cells less effective against bacteria and more noxious towards surrounding tissues.

2-Naphthylamine↗
PubMedDate not supplied

Effect of cigarette smoke extract on the polymorphonuclear leukocytes chemiluminescence: influence of a filter containing glutathione.

Cigarette smoking is known to be a risk factor for several chronic and neoplastic diseases. Many compounds formed by cigarette burning, ranging from particulate materials to water solutes and gaseous extracts, are considered to be noxious agents, and many biochemical and molecular mechanisms have been proposed for the toxic effects of cigarette smoke. The oral cavity and the upper respiratory tract represent the first contact areas for smoke compounds; even a single cigarette can produce marked effects on some components of the oral cavity, either chemical compounds, such as glutathione and enzymes, or cellular elements, such as polymorphonuclear leukocytes. Several studies suggest a protective role of glutathione against the noxious effects of tobacco smoke; the sulphydril groups of glutathione, in fact, could react with some smoke products, such as unsaturated aldehydes, leading to the formation of harmless intermediate compounds and simultaneously preventing the inactivation of metabolically essential molecules, such as some enzymes. In this paper we analyse the effect of a filter containing glutathione on the respiratory burst of polymorphonuclear leukocytes exposed to aqueous extract of cigarette smoke, measuring their chemiluminescence activity. The results of this paper indicate that the GSH-containing filter has a likely protective effect against the inhibition of cigarette smoke extract on polymorphonuclear leukocyte activity.

Filtration↗