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Evaluation of a Torsional-Vibrating Technique for the Hemorheological Characterization
Full text linkClinical measurement of blood viscosity is an important parameter in the diagnosis of different diseases (e.g., diabetes,
hypertension, cardiovascular diseases). The significance of blood viscosity in the microcirculatory flow is also of great
importance. Thus, a simple and accurate evaluation of hemorheological properties could be an important challenge in clinical
practice. Nowadays, validated measurements of plasma viscosity are commonly carried out with rotational viscometers by
means of the various geometric configurations. However, red blood cells deform under mechanical force and this aspect could
lead to an artificial variation in the apparent viscosity. In this work, an evaluation of a new technique for the viscosity determination
is focused. In particular, a torsional oscillation viscometer was adopted (VM10AL, CBC Europe) in the presence and in
the absence of stirring conditions at thermostated conditions. The profile of the rheological behaviour as a function of time was
recorded and compared with that obtained using a cone-plate rotational viscometer (AR300, TA Instrument)
Behavior of circulating endothelin-1 in a group of patients with acute myocardial infarction.
No full textThe aim of this study was to investigate the behavior of plasma endothelin-1 (ET-1) in 23 patients with acute myocardial infarction, complicated and uncomplicated by left ventricular failure, and treated with and without thrombolytic agents. ET-1 was measured on admission; on days 2, 3, and 5; and again on discharge. In addition, on discharge, ET-1 was correlated with left ventricular systolic function. Left ventricular failure was present, on admission, in 14 patients, whereas the other nine did not have any hemodynamic impairment. On discharge, no patients had left ventricular failure, but 11 had moderate to severe left ventricular systolic dysfunction, defined as left ventricular ejection fraction (LVEF) < 40%. Fourteen subjects, matched for age and sex, served as a control group. Compared with the control range, ET-1 was highly elevated on the first day, in both uncomplicated (p < 0.01) and complicated patients (p < 0.001). Then it decreased rapidly in the uncomplicated group, reaching the control range within day 5, whereas in the complicated group it remained significantly elevated in comparison with both the control subjects and the uncomplicated patients, until discharge. ET-1 was not correlated with the peak of creatine-kinase MB isoenzyme in any group. In seven patients submitted to thrombolytic treatment ET-1 was always significantly lower than in the nonthrombolyzed patients (p < 0.05), but the pattern of variation across time was no different. On discharge, the difference in plasma ET-1 between patients with LVEF < 40% and the control group was significant (p < 0.001), as was the difference between patients with and without moderate to severe systolic dysfunction (p < 0.01). ET-1 was closely and inversely correlated with LVEF when patients were considered as a whole (p < 0.001). These results suggest that the ET-1 increase in the early phase of myocardial infarction could be due to an ischemic process, to stress reaction, and to cardiac hemodynamic impairment, and therefore, ET-1 may be a good marker of disease. In the following phase the ET-1, being correlated with LVEF, could be a reliable index of systolic function
Valutazione della viscosità ematica sistemica correlata alla presenza di ulcere da pressione.
No full textComparison of blood viscosity using a torsional oscillation viscometer and a rheometer
Full text linkThe absence of a simple and clinically practical method to determine whole blood viscosity can partly justify why
the medical community has been slow in realizing the significance of whole blood viscosity. For this reason, the availability of a
technique able to evaluate blood viscosity in a rapid and direct manner is welcome. To evaluate the feasibility in hemorheological
laboratory of a new torsional oscillation viscometer, it was compared with a conventional cone–plate system. The viscosity
comparison has been related to hematocrit value both on whole blood and suspended blood in a saline solution. The results
showed a good repeatability and reproducibility of the new equipment, with a best-fitting data of the hematocrit 0–100% range
characterized by coefficient of determinations, r2 > 0.95. Furthermore, a comparison of whole blood viscosity as measured
by the two instruments was done on blood samples collected from hospitalized patients. Reasonable agreement for the viscosity
values was found between the two methods with linear determination coefficients between the two measurement methods
comprised between r2 = 0.7329 and 0.9263, depending on shear stress phase and the corresponding shear rate
High levels of human chromogranin A in umbilical cord, plasma and amniotic fluid at parturition
No full textModificazioni sulla viscosità ematica sistemica in soggetti allettati con ulcera da pressione
No full textTrombosi venosa profonda degli arti inferiori durante varicella in bambino con mutazione del fattore V di Leiden e deficit familiare di proteina S
No full text
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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