Biomedical subjects

Fernando Marco

Publications and source records attributed to Fernando Marco.

5 recordsLinked to original sources

PubMed2006

Patients who take uneven doses of acenocoumarol exhibit significant fluctuating levels of anticoagulation.

Acenocoumarol is the most widely used oral anticoagulant in Spain. In clinical practice it is usual to cut 4 mg tablets into halves and quarters, so that the total weekly dose may be uniformly distributed. Nevertheless, many patients are told to take uneven doses (e.g. 1/2 tablet one day and 1/4 tablet the next day). The impact of these variations in dosage over the stability of anticoagulation is unknown. We carried out a prospective study comparing a group of 40 patients taking uneven doses of acenocoumarol and another group of 10 patients with uniform doses. All patients were within the therapeutic range at inclusion in the study. The International Normalized Ratio (INR) was determined over two consecutive days in every patient to assess possible fluctuations of anticoagulation. Patients receiving an uneven dosage showed a greater variability of the INR value over two consecutive days, as opposed to patients receiving uniform doses. Variation of the INR resulted in a dose change in 27.5% of cases with uneven dosage and in none of the uniform dose cases. Consistent association was found between every INR value and the dose administered to the patient 2 days before (P < 0.01). Patients who take uneven doses of acenocoumarol exhibit significant fluctuating levels of anticoagulation. This fact has to be considered before making any change in the acenocoumarol dose. The INR value obtained depends greatly on the dose administered 2 days before determination of the INR.

Acenocoumarol↗

PubMed2004

Cryoprotectant permeation through human articular cartilage.

OBJECTIVE: The cryopreservation of intact articular cartilage is constrained by minimal chondrocyte survival. It was the aim of the present study to gain an insight into the permeation kinetics of cryoprotectants through cartilage. This knowledge is essential for achieving adequate tissue permeation prior to cooling. DESIGN: The diffusion coefficients and penetration rates through human articular cartilage of dimethyl sulfoxide (Me(2)SO) and glycerol at different temperatures (4 degrees C, 17 degrees C, 27 degrees C and 37 degrees C) and at two concentrations [10% (v/v) and absolute state] were measured using diffusion nuclear magnetic imaging. Deuterated water (D(2)O) was used as a control substance. RESULTS: Glycerol penetrated faster than Me(2)SO at all temperatures and at rates that were comparable to those for D(2)O. The penetration rate of each agent increased with increasing temperature. The diffusion coefficients for glycerol and Me(2)SO increased with increasing temperature and decreased at the higher concentration, but the differences between each agent were not significant. CONCLUSIONS: The classical cryopreservation protocols expose cartilage samples to Me(2)SO at a too low temperature and/or for an insufficient time period for optimal cell survival. When considering the penetration rate, glycerol appears to be a more efficient cryoprotective agent than Me(2)SO. The present study demonstrates the power of nuclear magnetic resonance technology to elucidate key physiological factors in cryobiology.

Adult↗

PubMed2003

Peripheral primitive neuroectodermal tumor after radiotherapy.

A 41-year-old man had a peripheral neuroectodermal tumor develop at the distal third of the fibula 4 years after radiotherapy for relapsed villonodular synovitis. This type of sarcoma usually is classified into the heterogeneic group of small round-cell bone tumors as a subdivision of Ewing's sarcomas. The immuno-staining positivity of the neoplastic cells for the neuron-specific enolase allowed the authors to make the diagnosis of a tumor with neuroectodermal origin. When the histologic study confirmed the diagnosis, the patient was treated with chemotherapy, surgical excision of the tumor, and adjuvant radiotherapy. Radiotherapy is thought to be involved in the genesis of osteogenic sarcomas as it has been shown in several reports, but there is no evidence in the literature of a peripheral neuroectodermal tumor developing after radiotherapy.

Adult↗

PubMed2001

Circulating levels of plasminogen activator inhibitor type-1, tissue plasminogen activator, and thrombomodulin in hemodialysis patients: biochemical correlations and role as independent predictors of coronary artery stenosis.

This study investigated the relationship between the circulating levels of the endothelial cell glycoproteins plasminogen activator inhibitor type 1 (PAI-1), tissue plasminogen activator (TPA), and thrombomodulin (TM) and the major vascular risk factors described in dialysis patients. In addition, the role of these endothelial cell products as independent predictors of coronary artery disease (CAD) was analyzed. Levels of TM, TPA antigen (Ag), TPA activity, PAI-1 Ag, PAI-1 activity, TPA/PAI complexes, thrombin-antithrombin complexes, fibrinopeptide A, C-reactive protein (CRP), interleukin-1beta and tumor necrosis factor-alpha, lipids, apoproteins A1 and B, and albumin were measured in a group of 200 nondiabetic dialysis patients and 100 healthy matched volunteers. When compared with healthy controls, dialysis patients showed increased levels of CRP, TM, TPA, and PAI-1 and evidence of increased thrombin-dependent fibrin formation. Increased levels of active PAI-1 were associated to a great extent with major classic vascular risk factors and to a lesser extent with CRP and serum triglycerides. Forty-six patients (23%) had evidence of CAD. Variables associated with CAD in the univariate analysis included age, time on dialysis, male gender, number of packs of cigarettes per year, high BP, fibrinogen, apolipoprotein B, albumin, PAI-1 activity, CRP, thrombin-antithrombin complexes, and fibrinopeptide A. Logistic regression analysis found age, high-density lipoprotein cholesterol, gender, high BP, CRP, time on dialysis, and PAI-1 activity to be independent predictors of CAD. This model classified correctly 85% of patients as having CAD and showed adequate goodness of fit for all risk categories. Our data support a pathogenic link among activated inflammatory response, endothelial injury, and CAD in hemodialysis patients and suggest that assessment of circulating PAI-1 levels could be an additional tool to identify dialysis patients who are at risk for developing atheromatous cardiovascular disease.

Case-Control Studies↗

PubMedDate not supplied

A prospective controlled study of a computer-assisted acenocoumarol dosage program.

The increase in oral anticoagulant (OA) treatment has led to development of new strategies for its control. We tested the efficacy of the GAO software (Dade Behring) in providing adequate acenocoumarol dosages for patients whose international normalised ratios (INRs) were no more than 0.5 points out of range. From December 1998 to August 1999, all outpatients in this setting were randomly assigned to receive computer-generated or traditionally fixed OA doses. Patients in their first 4 weeks of treatment were excluded. Overall, 8352 dosages were calculated by the computer and 7586 by the medical staff. The main endpoint of the study was the time spent in target INR range. The computer matched the traditional dosing, achieving a small but statistically significant greater efficacy in maintaining patients within the INR target range. The percentage of INR determinations over 5.5 was very low in both groups. Our results validate the computerised acenocoumarol dosing in our centre, achieving at least similar levels of effectiveness and safety compared with traditional dosage by medical staff.

Acenocoumarol↗