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Biomedical subjects

E Fernández

Publications and source records attributed to E Fernández.

At least 19 recordsLinked to original sources
PubMed2003

Influence of surfactant molecules as air-entraining agent for bone cement macroporosity.

Calcium phosphate bone cements (CPBCs) represent a potential synthetic alternative to bone-graft materials in bone surgery applications. CPBCs are biocompatible, bioresorbable, and slowly are replaced by new bone in vivo. However, CPBCs do not develop a macroporosity during setting that would allow fast bone ingrowth and good osteointegration of the implant. For this reason, recent research has approached the problem of inducing macroporosity inside the bone cement without influencing its normal setting. In this study, a new method for obtaining injectable macroporous CPBCs is proposed. It is based on the use of sodium dodecyl sulphate (SDS) as an air-entraining agent. The results have shown that the liquid-to-powder ratio and the SDS concentration, as well as the diameter and the interconnectivity of the macropores, can control the micro- and macroporosity. This new technology can be used to develop and optimize new commercial products for osteoporotic bone filling applications. Furthermore, the presented method also can be used at low temperatures before an operation to produce preformed implants to fit the particular needs of a patient.

Air↗
PubMed2003

An ultrasonic pulse-echo technique for monitoring the setting of CaSO4-based bone cement.

We present a new ultrasonic technique for monitoring the entire setting process of injectable bone cement. The problem with existing standards is their subjectivity. Because of this the results are not comparable between different research groups. A strong advantage with the proposed technique is that it is non-invasive and non-destructive, since no manipulation of the cement sample is needed once the measurement has started. Furthermore, the results are reproducible with small variations. The testing was performed on calcium sulfate cement using an ultrasonic pulse-echo approach. The results show that the acoustic properties of the cement are strongly correlated with the setting time, the density, and the adiabatic bulk modulus. The measured initial and final setting times agree well with the Gillmore needles standard. An important difference compared to the standards, is that the technique presented here allows the user to follow the entire setting process on-line.

Acoustics↗
PubMed2003

[Education and occupational social class: their relationship as indicators of socio-economic position to study social inequalities in health using health interview surveys].

AIM: To analyse the relationship between social class based on occupation and level of education in the study of social inequalities in health and use of health services. DESSIGN: Cross-sectional study (health interview survey). SETTING: General population of the city of Cornellà de Llobregat (Spain). PARTICIPANTS: Representative sample of subjects aged 14 years old or over (1043 men and 1101 women) who personally answered the questionnaire. MEASUREMENTS: We analyse the association between social class and level of studies and different independent variables (self-perceived health, smoking, medical visits) by means of logistic regression. RESULTS: The proportion of men who declare their self-perceived health as poor is higher among those who have low education (45.4%) than among those who have primary education level or higher (25.9%). The prevalence of smoking shows a similar pattern (54.2% versus 41.5%), with a gradient effect, which is statistically non-significant. However, these differences are no longer evident if social class is used to group the individuals. No clear association is observed between the use of health services and socio economic level. CONCLUSIONS: We need to use several indicators of socioeconomic position to evaluate social inequalities In this disadvantaged population, level of education seems to be a good indicator to study social inequalities in health.

Cross-Sectional Studies↗
PubMed2003

Systemic reactions to immunotherapy: influence of composition and manufacturer.

BACKGROUND: Although immunotherapy clearly demonstrated the benefit of reducing allergic symptoms, it has the drawback of adverse events, mainly systemic reactions that could be very inconvenient for patients and even life-threatening. OBJECTIVE: The aim of the present study was to assess the incidence of systemic reactions to immunotherapy in a large number of patients, and its potential relationship with the characteristics of therapy, such as allergen composition or manufacturing laboratory. METHODS: This study analysed the administration of specific immunotherapy during a period of 5 years, involving 1212 patients affected by respiratory hypersensitivity or hymenoptera venom anaphylaxis. Commercial extracts were supplied by five different laboratories. All the patients were attended at an out-clinic immunotherapy unit by the same experienced staff. Immunotherapy was given following a conventional schedule, modified according the usual recommendations. RESULTS: A total of 250 adverse reactions have been recorded, resulting in a frequency of 0.84% over the total number of injections. Seventy-nine of them (32%) were systemic reactions (0.27% SR/injection). The 79 systemic reactions were observed in 60 patients (5% of the patients). The frequency of systemic reactions was significantly lower (P < 0.01) on the group of mites than on the other groups. The frequency of systemic reactions varies according to the manufacturing laboratory. In the case of mite extracts, although one of the laboratories had a lower frequency of adverse systemic reactions, it did not reach the level of statistical significance. However, in relation to pollen extracts, preparations of one of the manufacturers had a significantly lower frequency of systemic reactions. Concerning the time of occurrence, 27% of systemic reactions were delayed, thus they appeared at least 30 min after the vaccine injection, most of them due to pollen extracts. CONCLUSION: This is a preliminary study to evaluate the factors that could facilitate the appearance of systemic reactions demonstrating that not only the composition but also the manufacturer is connected to systemic reactions. Although further studies are needed to clearly establish the influence of manufacturer on frequency and time of appearance of systemic reactions, it seems necessary to reach a wide consensus on allergen extract standardization methods.

Allergens↗
PubMed2003

[Influence of the vitamin D receptor gene polymorphism and 25-hydroxyvitamin D on arterial pressure in health individuals].

UNLABELLED: The role of vitamin D in the regulation of blood pressure is unclear. There are no studies that relate Bsm I polymorphism with blood pressure. OBJECTIVE: To analyze if Bsm I polymorphism and 25-hydroxyvitamin D (25OHD3) influence blood pressure in healthy individuals with normal blood pressure. METHODS: Systolic (SBP) and diastolic (DBP) blood pressure, Body Mass Index (BMI), plasma creatinine, serum calcium, serum phosphorus, serum iPTH, serum 25OHD3 and Bsm I genotype were determined in 590 healthy individuals (260 men and 330 women). Data were analysed using a multiple linear regression model. SBP and DBP were defined as dependent variables and the rest of variables as independent. RESULTS: Gender was strongly associated with both SBP (beta: -12.01, p: 0.000) and DBP (beta: -4.78, p: 0.000). Therefore, a separate analysis was performed according to gender. In males, SBP was associated with BMI (beta: 0.83, p: 0.001), 25OHD3, (beta: 0.36, p: 0.000) and genotype (beta: -3.90, p: 0.002); and DBP with 25OHD 3 (beta: 0.16, p: 0.018) and age (beta: 0.28, p: 0.000). Differences of blood pressure among the three genotypes were explored by analysis of variance. SBP was higher in men with bb genotype than in the other genotypes (p: 0.007). In females, 25OHD3 and genotype were not associated with blood pressure. CONCLUSIONS: Healthy men with higher levels of vitamin D have higher levels of SBP and DBP. Moreover, men with bb genotype have the highest levels of SBP. Blood pressure levels in women are not influenced by vitamin D nor by Bsml genotype. Our data suggest a possible pathophysiological interaction between vitamin D and sex hormones in blood pressure control.

Adult↗
PubMed2003

[Differential effect of vitamin D analogues on the proliferation of vascular smooth muscle cells].

Atherosclerosis is the principal cause of myocardial infarction, stroke, and peripheral vascular disease, accounting for nearly half of all mortality in developed countries. The excessive growth of vascular smooth muscle cells is an important component in the development of atherosclerotic lesion. The direct effect of calcitriol and vitamin D analogs on the VSMCs proliferation is not clear. In this study we have analysed if calcitriol, Paricalcitol (19-nor-1,25-dihydroxy-vitamin D2) and EB1089 (experimental analog used as anticancerous) modify proliferation and the expression of vitamin D receptor (VDR) gene that is regulated at the transcriptional level by itself in the VSMCs. VSMCs proliferation was analysed by BrdU incorporation and VDR gene expression using RT-PCR. VSMCs proliferation was stimulated when calcitriol was added to the culture. VSMCs proliferation was significantly lower with analogs at the same dose. With regard to the functional study, the expression of VDR gene was upregulated by calcitriol at a concentration of 100 nM. There were no changes in this expression with the analogs. In conclusion, calcitriol, do not modify VSMCs proliferation. Therefore, Paricalcitol could have a minor proliferating effect on the wall of vessels that vitamin D.

Animals↗
PubMed2003

Hereditary angioedema and pneumomediastinum.

Gastrointestinal and respiratory involvement is common in hereditary angioedema, laryngeal edema being the main cause of mortality in these patients. We report the case of an 18 year-old woman with a history of hereditary angioedema, who presented an episode of coughing and vomiting the night before, and who was diagnosed with pneumomediastinum as a complication of an episode of angioedema. We review the causes and pathogenesis of the mediastinic emphysema.

Adolescent↗
PubMed2002

Kinetic study of citric acid influence on calcium phosphate bone cements as water-reducing agent.

Most of the research performed on calcium phosphate bone cements (CPBCs) has dealt with the improvement of bone cement formulations for new, demanding bone-filling applications. In particular, the development of injectable bone cements is of real interest for the biomedical community. The aim of this work was to study the effect of citric acid on the injectability and the setting properties of alpha-tricalcium phosphate-based cements. A comparative kinetic study was performed on cements with and without citric acid relating the hardening curves and the hydration rates using a mathematical approach. Citric acid behaved as a fluidificant during the first stages of the cement mixing. The dissolution-precipitation reactions of the alpha-tricalcium phosphate were retarded with the addition of citric acid and the compressive strength at saturation increased. In conclusion, citric acid can behave as a water-reducing admixture.

Bone Cements↗
PubMed2002

Characterization of a novel calcium phosphate/sulphate bone cement.

Apatitic cements have shown excellent biocompatibility and adequate mechanical properties but have slow resorption in the human body. To assure that new bone tissue grows into the bone defect, a certain porosity is necessary although hard to achieve in injectable cements with suitable mechanical properties. An attempt was made by mixing alpha-tricalcium phosphate (alpha-TCP), calcium sulphate hemihydrate (CSH) and an aqueous solution containing 2.5 wt% of Na(2)HPO(4). The aim was to obtain a material containing two phases: a) one apatitic phase (calcium-deficient hydroxyapatite; CDHA) and b) one resorbable phase (calcium sulphate dihydrate; CSD). alpha-TCP and CSH mixtures were produced at relative intervals of 20 wt%. The liquid-to-powder (L/P) ratio to obtain a paste was 0.32 mLg(-1). The highest compressive strength (34 MPa) was obtained for the pure alpha-TCP sample. The strength was, in a first approximation, directly correlated to the weight proportions of the powders. X-ray diffraction analysis showed that the relative intensity for CDHA increased linearly, and the one for CSD decreased exponentially, when the amount of alpha-TCP increased. Thus, CSH ceased to transform to CSD when the amount of alpha-TCP increased. Observations in environmental scanning electron microscopy confirmed the X-ray diffraction results. CSH-crystals (100 microm) were embedded in the HA-matrix permitting gradual porosity in the material when resorbed.

Biocompatible Materials↗
PubMed2002

Effects of fluctuations on electrical properties of gap-junction connected cells in the turtle retina.

Electrical properties of gap-junction connected cells (input voltage and length constant) are shown to depend strongly on fluctuations in membrane and contact conductances. This opens new possibilities and incorporates a further difficulty to the analysis of electrophysiological data, since four, instead of two, parameters (the average values and the magnitude of fluctuations of the two conductances) have to be used in fitting the experimental data. The discussion is illustrated by investigating the effects of dopamine on signal spreading in horizontal cells of turtle retina, assuming a linear cell arrangement. It is shown that while a standard fitting with the average values of the two conductances leads to the conclusion that both are equally affected by dopamine, including fluctuations allows fitting the data by varying just the average contact conductance plus the magnitude of fluctuations.

Animals↗
PubMed2002

[Tolerability and efficiency of a new transdermic nitroglycerin patch in outpatients with chronic stable angina. The PATRICH Trial].

OBJECTIVE: To obtain data on local and systemic tolerability of three different doses (5 mg/24 h, 10 mg/24 h, and 15 mg/24 h) of a new model of nitroglycerin patch (Trinipatch, Sanofi-Synthelabo, S. A.) in patients with chronic stable angina. METHODS: A total of 954 patients were studied for a follow-up period of 12 weeks. Patients were distributed as follows: 132 to the 5 mg/24 h patch, 727 to the 10 mg/24 h patch, and 95 to the 15 mg/24 h patch. The local tolerability was evaluated by using the Draize scale and the systemic tolerability by recording the adverse reactions and assessing the effect on blood pressure. Furthermore, the efficiency of therapy was evaluated by means of the variations observed in the number and severity of angina crises, as well as the weekly use of sublingual nitroglycerine. RESULTS: Ninety-four patients (9.8%) showed signs of cutaneous irritation. Thirty-two patients (3.3%) showed erythema, and one patient (0.1%) showed erythema and induration. Thirty-nine patients (4.1%) had some type of systemic adverse reaction during the study. A total of 44 adverse reactions were recorded, headache being the most common (79.5%). Only one severe adverse reaction was observed (mild heart failure), which in the opinion of the researcher was not related to the medication. No dropouts were recorded on account of adverse reactions. The number of patients with angina crises and the number of weekly angina crises decreased significantly with therapy. CONCLUSIONS: The transdermic nitroglycerin patch was demonstrated to be a safe and well tolerated therapy for chronic stable angina, both in terms of local and systemic tolerability. Moreover, its efficiency was demonstrated as the number of angina crises decreased significantly.

Administration, Cutaneous↗
PubMed2002

[Survey on the needs expressed by primary care doctors for continuing education in drug therapy].

OBJECTIVE: To describe the aspects of continuing education in pharmacological therapeutics considered as most relevant by the primary health care physicians. DESIGN: Observational study.Setting. Physicians filled-up the questionnaires during 45 minutes at their primary health care centres. PARTICIPANTS: Primary health care physicians involved in the Fundation Institut Català de Farmacologia continuing education activities since 1997 were selected. MAIN MEASUREMENTS: A specific questionnaire was designed to collect the physicians' opinion on different topics regarding continuing education in pharmacological therapeutics. RESULTS: 180 physicians from 21 primary health care centres answered the questionnaire. 68% of the responding physicians considered that continuing education has to be useful to improve routine clinical practice. Regular seminars and methods stimulating active participation administered by primary health care professionels are preferred. Continuing education in pharmacological therapeutics should be focused to health problems rather than being drug-oriented. They referred being more interested in drug selection issues and in the role of new drug in comparison with the existing alternatives rather than in regulation and drug consumption issues. 66,3% of the responding physicians considered that continuing education in pharmacological therapeutics should be compulsory. Public health authorities and primary health care physicians should share the responsibility in setting-up continuing education in pharmacological therapeutics programs, according to the opinion of almost 70% of the physicians. CONCLUSIONS: Primary health care physicians are interested in continuing education in pharmacological therapeutics as far as it is practical and useful to solve problems of their routine clinical practice.

Adult↗
PubMed2002

Photophysical, photochemical, and thermodynamic properties of shikimic acid derivatives: calycin and rhizocarpic acid (lichens).

Photophysical and photochemical parameters of the lichen metabolites calycin and rhizocarpic acid were determined. Experiments were carried out in micellar solutions of 3% Brij 35, at pH 2 and 12, and in acetonitrile. Both metabolites absorb in the UV-A and UV-B regions, and emit fluorescence in the visible region of the solar spectrum. Shifts were not observed in the absorption spectra, at pH 2 and 12. The low phi(c), between 10(-5) and 10(-2), shows that both compounds are photostable in the experimental conditions. For rhizocarpic acid, two values of pK(a) were obtained: 5.1 corresponding to the hydroxyl group, and 9.0 corresponding to the protonated nitrogen. Calycin presents only one value of pK(a): 4.9, that is attributed to the hydroxyl group. L-(+)-Gluconic-gamma-lactonic acid was used as a reference model; the compound showed greater photoinstability, demonstrating that the photodegradation observed occurs mainly in the oxolane carbonylic ring.

Hydrogen-Ion Concentration↗
PubMed2002

Streptococcus entericus sp. nov., isolated from cattle intestine.

Biochemical, molecular chemical and molecular genetic studies were performed on an unknown gram-positive, catalase-negative, coccus-shaped organism isolated from the intestine of a cow affected with catarrhal enteritis. The organism was tentatively identified as a streptococcal species based on results of cellular morphological and biochemical tests. 16S rRNA gene sequencing studies confirmed its provisional identification as a member of the genus Streptococcus, but the organism did not correspond to any recognized species of this genus. The nearest phylogenetic relatives of the unknown coccus from a calf were Streptococcus acidominimus and Streptococcus suis. The unknown bacterium, however, was distinguished from these species and other animal streptococci by biochemical tests and electrophoretic analysis of whole-cell proteins. Based on both phenotypic and phylogenetic findings, it is proposed that the unknown bacterium be classified as a novel species of the genus Streptococcus, Streptococcus entericus sp. nov. The type strain is CECT 5353T (= CCUG 44616T).

Animals↗