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Biomedical subjects

D Baldassarre

Publications and source records attributed to D Baldassarre.

At least 19 recordsLinked to original sources
PubMed2001

Cardiovascular status of carriers of the apolipoprotein A-I(Milano) mutant: the Limone sul Garda study.

BACKGROUND: Carriers of the apolipoprotein A-I(Milano) (apoA-I(M)) mutant present with very low plasma HDL cholesterol and moderate hypertriglyceridemia, apparently not leading to premature coronary heart disease. The objective of this study was to establish whether this high-risk lipid/lipoprotein profile is associated with structural changes in the carotid arteries and heart, indicative of preclinical atherosclerosis. METHODS AND RESULTS: Twenty-one A-I(M) carriers were compared with age- and sex-matched control subjects from the same kindred and with 2 series of matched subjects with primary hypoalphalipoproteinemia (HA). Structural changes in the carotid arteries were defined as the intima-media thickness (IMT) measured by B-mode ultrasound. HA subjects, both recruited among patients attending our Lipid Clinic and blood donors, showed significant thickening of the carotids (average IMT, 0.86+/-0.25 and 0.88+/-0.29 mm, respectively) compared with control subjects (average IMT, 0.64+/-0.12 mm); the apoA-I(M) carriers instead showed normal arterial thickness (average IMT, 0.63+/-0.10 mm). Moreover, a significantly higher prevalence of atherosclerotic plaques was found in patients and blood donors with HA (both 57%) compared with apoA-I(M) carriers (33%) and control subjects (21%). Echocardiographic findings and maximal treadmill ECG did not differ significantly between apoA-I(M) carriers and control subjects, apart from a slight increase in left ventricular end-diastolic dimension in the carriers. CONCLUSIONS: Despite severe HA, carriers of the apoA-I(M) mutant do not show structural changes in the arteries and heart, in contrast to HA subjects, who are characterized by a marked increase in carotid IMT and increased prevalence of atherosclerotic plaques.

Adult↗
PubMed2001

Time course of forearm arterial compliance changes during reactive hyperemia.

Ultrasonic studies have shown that arterial compliance increases after prolonged ischemia. The objective of the present study was to develop an alternative plethysmographic method to investigate compliance, exploring validity and clinical applicability. Forearm pulse volume (FPV) and blood pressure (BP) were used to establish the FPV-BP relationship. Forearm arterial compliance (FAC) was measured, and the area under the FAC-BP curve (FAC(AUC)) was determined. The time course curve of compliance changes during reactive hyperemia was obtained by continuous measurements of FAC(AUC) for 20 s before and for 300 s after arterial occlusion. This technique allows us to effectively assess compliance changes during reactive hyperemia. Furthermore, the selected measurement protocol indicated the necessity for continuous measurements to detect "true" maximal FAC(AUC) changes. On multivariate analysis, preischemic FAC(AUC) was mainly affected by sex, peak FAC(AUC) was affected by sex and systolic BP, percent changes were affected by plasma high-density and low-density lipoprotein cholesterol, peak time was affected by age and body mass index, and descent time was affected by plasma triglyceride levels. The proposed technique is highly sensitive and well comparable with the generally accepted echotracking system. It may thus be considered as an alternative tool to detect and monitor compliance changes induced by arterial occlusion.

Adolescent↗
PubMed2000

Intima-media thickness after pravastatin stabilizes also in patients with moderate to no reduction in LDL-cholesterol levels: the carotid atherosclerosis Italian ultrasound study.

The Carotid Atherosclerosis Italian Ultrasound study (CAIUS), a multicenter, double-blind clinical trial, performed in 305 asymptomatic, moderately hypercholesterolemic patients, clearly demonstrated beneficial effects of pravastatin on the carotid intima-media thickness (IMT) progression. The database of the CAIUS study was examined in order to investigate the presence of a relationship, if any, between the activity of pravastatin on IMT progression rate and its hypocholesterolemic effect. Quantitative B-mode ultrasound imaging was used to quantify the individual mean maximum IMT progression rate in 3 years. In the overall group of patients (placebo and pravastatin) covariance analysis showed that while the variable 'treatment' (0 = placebo, 1 = pravastatin) was significantly related to the reduction of IMT progression (F= 6.6, P = 0.01), the IMT progression did not correlate with the extent of LDL-C lowering (F= 0.00, P = 0.98). To further investigate this issue. the pravastatin treated group was stratified into quartiles of LDL-C reduction. In contrast to what was observed in the placebo group, in which a positive mean IMT progression rate was observed, independent of the extent of LDL-C reduction, no IMT progressionwas observed in any subgroup treated with pravastatin. No significant difference was found among quartiles and no trend could be identified. In conclusion, the effect of pravastatin treatment on carotid IMT progression rate is beneficial; however the CAIUS study demonstrated that lowering LDL-C by itself, does not explain the variability of beneficial changes in IMT.

Anticholesteremic Agents↗
PubMed2000

Carotid artery intima-media thickness measured by ultrasonography in normal clinical practice correlates well with atherosclerosis risk factors.

BACKGROUND AND PURPOSE: The intima-media thickness (IMT) of extracranial carotid arteries determined by B-mode ultrasound is a measurable index of the presence of atherosclerosis. The ultrasonographic scan protocol and the scan reading techniques used until now to measure IMT are, however, time consuming and require the participation of specialized research centers. In this study we present a cross-sectional study of 963 patients attending the Enrica Grossi Paoletti Center in Milan, Italy, with the aim of assessing whether ultrasonographic measurements of carotid artery in routine clinical practice can yield the same results as those obtained with quantitative methods used until now in clinical trials. METHODS: Maximum and mean maximum IMT of carotid arteries were assessed by B-mode ultrasound with the use of the electronic caliper of the machine in real time. RESULTS: The intraobserver and interobserver variability of IMT of carotid arteries performed with the electronic caliper in real time was similar to that of quantitative processing of frozen images (coefficients of variation of intraobserver and interobserver mean maximum IMT measurements were 4.2% and 7.3%, respectively). Carotid artery IMT thus measured correlated with most of the known atherosclerosis risk factors and discriminated between patients with and without previous history of cardiovascular events. IMT was linearly related to the total number of vascular risk factors both in the whole group and after stratification of patients into 3 age classes. CONCLUSIONS: These observations establish a strong correlation between B-mode imaging of carotid atherosclerosis evaluated in normal clinical practice and data provided by clinical trials and validate this simple reading technique as a means of identifying IMT as another possible risk factor in patients at high risk of vascular disease.

Arteriosclerosis↗
PubMed2000

Reproducibility validation study comparing analog and digital imaging technologies for the measurement of intima-media thickness.

BACKGROUND AND PURPOSE: New advances in B-mode imaging technologies have led to improved quality in the detection of minute changes in the surface of intima-media thickness (IMT) and plaques. The new digital systems, with increased numbers of imaging channels, multiple frequency probes, and increased microprocessing speeds, now generate images comparable to those of the analog predecessors. Can these digital systems have reproducibility comparable to that of a pure analog system? We compared the Biosound 2000II (analog) system with the Esaote AU4 (digital) system. METHODS: Twenty-two subjects were chosen who had varying degrees of IMT on the far wall of the common carotid artery. Common carotid IMT was determined twice: the first time with the analog system and the second time with the digital system. With each system, replicate scans were made within 2 weeks. RESULTS: The intramethod agreement was high with the analog system, with a bias between readings of -0.010+/-0.033 mm, mean absolute difference of 0.027+/-0.020 mm, repeatability coefficient of 0.067, and correlation coefficient of 0.97. The digital system provided the highest reproducibility with a bias between readings of 0.002+/-0.016 mm, mean absolute difference of 0.012+/-0.011 mm, repeatability coefficient of 0.033, and correlation coefficient of 0. 99. When the analog and digital systems were compared, the bias between readings was -0.011+/-0.024 mm with good agreement between the 2 systems; the repeatability coefficient was 0.047, with all points within +/-2 SDs of the mean difference. The mean absolute difference between the 2 measurements was 0.018+/-0.015 mm with a correlation coefficient of 0.98. CONCLUSIONS: The digital system for IMT evaluation compares well with the more widely used analog system and provides a reliable technology for common carotid IMT measurement that can be applied to clinical trials.

Carotid Arteries↗
PubMed2000

Relationship between fibrinolytic and metabolic variables: a study in patients attending a lipid clinic.

We investigated the relationship between plasma levels of metabolic and fibrinolytic variables in 163 fasted patients attending a lipid clinic. Of these patients, 118 had hypertriglyceridaemia (HTG) and 45 had normotriglyceridaemia (NTG). In HTG, basal fibrinolytic activity, ie tissue plasminogen activator (t-PA) activity, was impaired as a result of high plasminogen activator inhibitor type 1 (PAI-1) antigen and activity. Multiple stepwise regression analysis identified insulin and triglyceride levels as independent determinants of plasma PAI-1 levels (R2 = 0.18; P = 0.0001). When the patients were stratified into tertiles according to their levels of triglyceride and insulin, PAI-1 antigen levels were found to increase with rising levels of triglyceride in each insulin tertile. In contrast, the increase of PAI-1 with rising insulin levels was evident in the highest triglyceride tertile. In addition, subjects in the lowest tertile of both triglyceride and insulin had the lowest PAI-1 antigen levels, and subjects in the highest tertile of both triglyceride and insulin had the highest levels of PAI-1. Both basal and stimulated levels of t-PA antigen were significantly higher in HTG than in NTG. Multiple stepwise regression analysis identified triglyceride level as the sole major determinant of t-PA antigen levels (R2 = 0.13; P = 0.00003). The observation that both insulin and triglycerides correlate with PAI-1, whereas triglycerides were involved only in the increased secretion of t-PA, suggests that these two proteins are regulated by different mechanisms.

Adolescent↗
PubMed2000

L-carnitine reduces plasma lipoprotein(a) levels in patients with hyper Lp(a).

BACKGROUND AND AIMS: Elevated Lp(a) levels are a significant cardiovascular risk factor, particularly for young individuals and for subjects with concomitant high LDL cholesterol. Increased Lp(a) is believed to be linked to an enhanced production of the lipoprotein, controlled by genetic factors; it can be reduced by agents such as nicotinic acid, lowering free fatty acid inflow to the liver. METHODS AND RESULTS: L-carnitine, a natural compound stimulating fatty acid oxidation at the mitochondrial level, was tested in a double blind study in 36 subjects with Lp(a) levels ranging between 40-80 mg/dL, in most with concomitant LDL cholesterol and triglyceride elevations. L-carnitine (2 g/day) significantly reduced Lp(a) levels (-7.7% vs baseline and -11.7% vs placebo treatment), the reduction being more dramatic in the subjects with the more marked elevations. In particular, in the L-carnitine group, 14 out of 18 subjects (77.8%) had a significant reduction of Lp(a) vs only 7 out of 18 (38.9%) in the placebo group (chi 2 = 4.11, p = 0.0452). In a significant number of subjects the reduction of Lp(a) resulted in a return of this major cardiovascular risk parameter to the normal range. CONCLUSIONS: L-carnitine offers a potentially useful therapeutic agent for atherogenic conditions characterized by high Lp(a) levels, also in view of the excellent tolerability and essential lack of major side effects.

Aged↗
PubMed1999

Effect of plasma cholesterol reduction by pravastatin on the functional properties of forearm arteries in hypercholesterolemic patients.

BACKGROUND AND AIM: Since functional properties in the vasculature of hypercholesterolemic subjects are impaired, a six-month pravastatin treatment (20 mg/die) was tested in an open design, on the impaired unstimulated forearm arterial compliance (Un-FAC(AUC)) of 14 asymptomatic type IIa familial hypercholesterolemic patients. In order to evaluate whether FAC(AUC) changes might be related to the extent of cholesterol reduction achieved, this evaluation was carried out in five severely hypercholesterolemic patients, undergoing LDL-apheresis. METHODS AND RESULTS: Arterial functional properties, i.e. FAC(AUC) responses to glyceryl trinitrate (GTN-FAC(AUC)) and acetylcholine (ACh-FAC(AUC), four patients) and the effects on rest and peak forearm blood flow and vascular resistance were evaluated on the non-dominant arm using plethysmographic methods, that also allow the direct assessment of the non-linear "compliance-blood pressure" curve. Selective LDL-apheresis was performed by using a dextran-sulphate column. Pravastatin effectively lowered plasma total (-16%, p = 0.002) and LDL cholesterol levels (-22%, p = 0.006 vs baseline). Rest and peak flow, basal and post ischemic vascular resistance were not affected as well as Un-FAC(AUC) and GTN-FAC(AUC). However, in the four hypercholesterolemic patients undergoing ACh infusion, there was an improvement in the ACh-FAC(AUC) of borderline statistical significativity (p = 0.056). LDL-apheresis reduced plasma total and LDL cholesterol levels by 55% and 59%, without affecting blood pressure. In this series of five patients Un-FAC(AUC) increased, the Un-FAC(AUC) rise being inversely related to the absolute reduction of plasma total (r = 0.92, p < 0.05) and LDL cholesterol (r = 0.89, p < 0.05) levels. CONCLUSIONS: In hypercholesterolemic patients a short-term hypocholesterolemic treatment with pravastatin, although able to improve the lipid profile, cannot alter significantly blood flow, vascular resistance, Un-FAC(AUC) and GTN-FAC(AUC). A possible selective improvement in the ACh-receptor-activated signal transduction pathway has been observed and the importance of a drastic reduction of cholesterol concentrations in order to affect the Un-FAC(AUC) is suggested.

Acetylcholine↗
PubMed1997

Platelet alpha 2-adrenergic receptors in hypercholesterolemia: relationship between binding studies and epinephrine-induced platelet aggregation.

BACKGROUND: Platelets isolated from patients with hypercholesterolemia are more sensitive in vitro to various aggregating agents, including epinephrine, than those isolated from normocholesterolemic subjects. Increased platelet reactivity is one mechanism that may explain the enhanced risk of thromboembolism in hypercholesterolemia. This study assessed whether platelet hyperreactivity to epinephrine in hypercholesterolemia is associated with higher alpha 2-adrenergic receptor density or affinity for epinephrine. METHODS: Platelet aggregation and binding studies, with use of [3H]yohimbine as ligand, were performed on platelets isolated from 30 patients with type IIa hypercholesterolemia and 23 control subjects. RESULTS: Platelet aggregation in response to epinephrine was significantly higher in patients with hypercholesterolemia than in control subjects. A statistically significantly higher alpha 2-adrenergic receptor density was observed in a subgroup of 13 patients with hypercholesterolemia than in 13 sex- and age-matched control subjects (280 +/- 61 and 230 +/- 49 fmol/mg protein respectively; p < 0.03), but no difference was observed in receptor affinity for the ligand. In these subgroups plasma total and levels of low-density lipoprotein (LDL) cholesterol were inversely correlated with platelet aggregation but directly correlated with platelet receptor density. CONCLUSION: Platelet alpha 2-adrenergic receptor density is increased in hypercholesterolemia and directly correlates with plasma total and levels of LDL cholesterol, providing at least a partial explanation for the enhanced platelet response to epinephrine that is observed in hypercholesterolemia.

Adrenergic alpha-Antagonists↗
PubMed1997

Clinical evaluation of probucol in hypercholesteremia: individual lipoprotein responses and inhibitory effect on carotid atherosclerosis progression.

Probucol treatment has been evaluated in 140 patients with hypercholesterolemia attending a single Lipid Clinic, in an attempt to identify the relations between lipid/lipoprotein responses and patient characteristics. Probucol was administered as a single drug at the standard dose (0.5 g tablets b.i.d.) for at least 6 months. One-hundred (71%) patients displayed a reduction of low-density lipoprotein cholesterol (LDL-C), which was significantly correlated with the baseline LDL-C level (r = 0.64; p < 0.0001). Most of the patients (90%) also responded with a reduction of high-density lipoprotein cholesterol (HDL-C); the HDL-C reduction was also directly related to baseline HDL cholesterolemia (r = 0.67, p < 0.0001). A highly significant correlation was found between the individual LDL-C and HDL-C responses. Eleven patients who continued with probucol treatment had a B-mode ultrasonographic investigation performed at baseline and after 24 months. No changes in carotid mean and maximal intimal-medial thickness were recorded, in contrast to an increase (i.e., indicative of atherosclerosis progression) in matched patients with hypercholesterolemia receiving other lipid-lowering regimens. Our report underlines that probucol can still provide a valuable option for the treatment for hypercholesterolemia, being particularly effective in patients with a combined increase of LDL-C and HDL-C levels.

Adult↗
PubMed1996

Iron-ovotransferrin preparation does not interfere with ciprofloxacin absorption.

Iron supplements can interfere with the bioavailability of a number of drugs, including thyroxine, tetracycline derivatives, penicillamine, methyldopa, levodopa, carbidopa, ciprofloxacin, and the newer fluoroquinolones. A new iron formulation was tested in which iron ions are bound to ovotransferrin, a protein that shares more than an 80% similarity with the sequence of human transferrin and apparently is less likely than the commonly used iron salts to reduce drug absorption. Ciprofloxacin was taken as a model drug, of wide use and restricted range of therapeutic levels, and its absorption was evaluated after the administration of the iron-ovotransferrin complex versus an iron-gluconate formulation in healthy volunteers. At variance with the iron gluconate formulation, which led to a reduction of about 50% of peak serum ciprofloxacin levels (Cmax; 1.0 +/- 0.2 versus 2.4 +/- 0.3 micrograms/ml; p < 0.01) and of the area under the serum concentration-time curve from time 0 to infinity [AUC(0 - infinity); 10.1 +/- 1.1 versus 18.3 +/- 1.0 mg.L-1.hr; p < 0.01], the iron-ovotransferrin complex caused only modest, non significant changes in absorption with a minimal reduction of the AUC[0 - infinity) (17.3 +/- 1.0 versus 18.3 +/- 1.0 mg.L-1.hr; difference not significant) and a nonsignificant decrease in the Cmax (2.2 +/- 0.3 versus 2.4 +/- 0.3 microgram/ml; difference not significant). Iron was also well absorbed from the formulation in the presence of a fatty meal. The very common drug interactions with oral iron preparations can be effectively prevented by the use of the iron-ovotransferrin complex interacting to a minimal extent with a sensitive drug with a reduced margin of efficacy, such as ciprofloxacin.

Adult↗
PubMed1996

Plasminogen activator inhibitor type-1 synthesis and mRNA expression in HepG2 cells are regulated by VLDL.

The effect of VLDL on plasminogen activator inhibitor type 1 biosynthesis in HepG2 cells was investigated. Exposure of HepG2 cells to VLDL (range, 10 to 100 micrograms protein per milliliter) for 16 hours resulted in an enhanced release of PAI-1 antigen and PAI activity into conditioned medium, accompanied by the accumulation of intracellular triglycerides. By using a monoclonal antibody (IgG C7) specific to the LDL receptor, we showed that the effect of VLDL is mediated by its interaction with the LDL receptor. Enhanced PAI-1 release was due to increased biosynthesis: PAI-1 mRNA was doubled, mainly because of the effect on the 2.2-kb PAI-1 mRNA rather than the 3.2-kb transcript. Addition of insulin with the VLDL further enhanced PAI-1 antigen release and PAI-1 mRNA accumulation. The effect of VLDL on steady state levels of PAI-1 mRNA was apparently not due to an increase of gene transcription but to stabilization of both PAI-1 mRNA transcripts. The enhancing effect of VLDL on PAI-1 biosynthesis in HepG2 cells may raise PAI-1 antigen levels not only in hypertriglyceridemic states but also in those conditions in which both insulin and VLDL are elevated.

Carcinoma, Hepatocellular↗
PubMed1996

Relation between hemostatic variables and increase of common carotid intima-media thickness in patients with peripheral arterial disease.

BACKGROUND AND PURPOSE: Increases in common carotid intima-media thickness (CC-IMT), as measured by B-mode ultrasonography, have been widely used in both population studies and clinical trials in the search for risk factors for early atherosclerosis progression and have been found to correlate with age and with high concentrations of low-density lipoprotein cholesterol, leukocytes, and hemoglobin. We have now investigated the relation between several baseline hemostatic and conventional risk factors and CC-IMT changes over 16 months in 64 patients with peripheral arterial disease randomly selected from the prospective PLAT study series. METHODS: Samples from 24 patients (37.5%) who showed increases in CC-IMT during the follow-up period were compared with those from 40 (62.5%) in whom CC-IMT remained unchanged. RESULTS: Baseline conventional risk factors and coagulation variables were similar in the two groups except for higher plasma concentrations of von Willebrand factor (vWF) (178.3 +/- 53.6% versus 141.2 +/- 53.7%, P=.01) and factor VII (FVII) (133.9 +/- 36.4% versus 107.0 +/- 27.3%, P=.001) in the patients with increased CC-IMT. CC-IMT increase correlated positively with plasma levels of FVII (r=.31, P<.01) and vWF (r=.31, P<.01). Multiple stepwise regression analysis identified FVII as the only independent variable associated with an increase in CC-IMT (beta=.83, P=.01). CONCLUSIONS: High plasma concentration of FVII and vWF may be associated with the progression of early carotid atherosclerosis in patients with peripheral arterial disease.

Age Factors↗
PubMed1996

Plasma lipoprotein(a) is an independent factor associated with carotid wall thickening in severely but not moderately hypercholesterolemic patients.

BACKGROUND AND PURPOSE: To evaluate whether high levels of low-density lipoprotein cholesterol (LDL-C) may promote the atherogenic effect of lipoprotein(a) [Lp(a)], we investigated the association between elevated Lp(a) levels and thickening of intima plus media in the common carotid artery (CC-IMT) in patients with different degrees of hypercholesterolemia. METHODS: One hundred type II hypercholesterolemic patients and 25 normolipidemic subjects were selected for the study. Plasma lipid and lipoprotein levels were determined enzymatically; Lp(a) levels were determined by enzyme-linked immunosorbent assay. An Lp(a) concentration > 30 mg/dL was arbitrarily considered a risk factor. For each patient mean CC-IMT was determined by B-mode ultrasound; in 60 patients and in the 25 control subjects, the maximal IMT in the entire carotid tree was also determined. RESULTS: CC-IMT values were higher in hypercholesterolemic patients with plasma Lp(a) levels > 30 mg/dL than in those with lower levels (P < .01). CC-IMT and maximal IMT directly and independently correlated with plasma levels of Lp(a) (r = .33 and r = .25, respectively; both P < .05). The effect of LDL-C concentrations on the relationship between IMT and Lp(a) was investigated by dividing the patients into quartiles of plasma LDL-C levels. After stratification, CC-IMT significantly correlated with plasma Lp(a) levels in the patients with severe hypercholesterolemia (LDL-C > 5.2 mmol/L) but not in patients in the lowest quartile, ie, those with moderate hypercholesterolemia. No correlation between CC-IMT and Lp(a) was found in normolipidemic control subjects. CONCLUSIONS: Elevated plasma levels of Lp(a) can be considered an additional independent factor associated with thickening of the common carotid arteries in patients with severe hypercholesterolemia but not in those with moderate hypercholesterolemia or in normocholesterolemic subjects.

Adult↗
PubMed1995

Non-invasive assessment of unstimulated forearm arterial compliance in human subjects. Impaired vasoreactivity in hypercholesterolaemia.

A study was carried out in order to determine the feasibility and reproducibility of a direct plethysmographic assessment of unstimulated forearm arterial compliance (FAC) in hypercholesterolaemic and normocholesterolaemic subjects. Simultaneous recordings of forearm pulse volume and blood pressure over the whole cardiac cycle are used to establish the pulse volume-blood pressure relationship. FAC was measured on-line by computing the ratio of dV/dP. The area under the curve (FAC(AUC)) of FAC/blood-pressure curve was determined in a standard range of blood pressure (70-130 mmHg). The method was validated by demonstrating its capacity to detect changes in FAC(AUC) induced by nitrate and by muscarinic stimuli. The results show a reduced FAC(AUC) in hypercholesterolaemic patients vs. controls (2.28 +/- 0.8 x 10(-3) vs. 4.12 +/- 1.06 x 10(-3) (mL 100 mL-1 forearm mmHg-1) mmHg; P = 0.0001). The method appears to be highly sensitive to nitrate and muscarinic stimuli. The new technique provides a potentially useful tool to detect and monitor in vivo, without stimulating arterial dilatation, e.g. by acetylcholine infusion, the functional arterial changes in subjects with a major risk factor for arterial disease as well as the effects of dietary/drug treatments.

Acetylcholine↗
PubMed1994

Glycosylation pattern of platelet glycoprotein IIb and IIIa in type IIa hypercholesterolemia.

The microheterogeneity and polymorphism of platelet membrane glycoproteins IIb and IIIa from hypercholesterolemic type IIA patients and from normolipidemic controls were compared by isoelectric focusing followed by immunological detection. Their size and the extent of glycosylation were investigated by polyacrylamide gel electrophoresis and carbohydrate affinity stain. No qualitative or quantitative differences could be detected, either within each test group or between the two groups. This finding rules out the hypothesis that altered molecular forms of the glycoproteins forming the fibrinogen receptor might be involved in the pathogenesis of platelet hyperaggregability in hypercholesterolemic patients.

Electrophoresis, Polyacrylamide Gel↗
PubMed1994

Common carotid intima-media thickness measurement. A method to improve accuracy and precision.

BACKGROUND AND PURPOSE: High-resolution ultrasonographic imaging is a noninvasive method that allows estimation of the thickness of the intima-media complex in human carotid arteries. The determination of intima-media thickness involves several steps, each of which may introduce an error that influences the reproducibility of the method. In the present study, apart from the general reproducibility of the determination of intima-media thickness, the error introduced by each step was evaluated. METHODS: B-mode scans were performed on 14 randomly selected patients. The common carotid arteries were examined in anterior, lateral, and posterior planes, with a standard methodology and by a new method, making use of external reference points. RESULTS: The error in general reproducibility in determination of the subject's mean intima-media thickness was 5.9%. This parameter was also evaluated in a paired manner after dividing the whole artery into sectors; with this protocol, the percent error in general reproducibility was 15%. The main source of variability in the evaluation of common carotid intima-media thickness was found to lie in the operator's subjectivity in the choice of the carotid sector to be processed (percent error, 10.27%). A method was therefore designed that used external reference points, resulting in reduction of this error by 38.2%. CONCLUSIONS: While the mean intima-media thickness might be considered a reproducible parameter to evaluate differences between populations exposed to diverse risk factors, evolutional or therapy-induced changes in the individual may be better monitored on defined carotid sectors. This may be achieved with a high reproducibility by use of the proposed method based on external reference points.

Carotid Arteries↗