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Biomedical subjects

A Rodríguez

Publications and source records attributed to A Rodríguez.

At least 91 records · Page 5Linked to original sources
PubMed2001

Trypanosoma cruzi: inhibition of parasite growth and respiration by oxazolo(thiazolo)pyridine derivatives and its relationship to redox potential and lipophilicity.

Chagas' disease constitutes a therapeutic challenge because presently available drugs have wide toxicity to the host and are generally ineffective in the chronic stages of the disease. A series of oxazolo(thiazolo)pyridene derivatives were studied on Trypanosoma cruzi epimastigote growth and oxygen consumption and their electrochemical (redox) potentials and lipophilicity. The derivatives produced different degrees of parasite growth and respiration inhibition on CL Brener, LQ, and Tulahuen strains of T. cruzi epimastigotes. Respiratory chain inhibition appears to be a determinant of the trypanosomicidal activity of these compounds, since a significant correlation between respiration and culture growth inhibition was found. A similar correlation was found, within the different structural subfamilies, between toxic effects and the ability of the compounds to be oxidized in aqueous media. The inhibition of respiration and of parasite growth in culture increases with the lipophilicity of the substituents on the oxazolopyridine nucleus. No difference in the action of these derivatives was found among the different parasite strains. It is concluded that these compounds may have a potential usefulness in the treatment of Chagas' disease.

Animals↗
PubMed2001

[Evaluation of the anatomopathological characteristics and the safety of radiofrequency lesions at the atrial level with two different systems of irrigated tip catheters on an experimental level].

INTRODUCTION AND OBJECTIVES: We performed this study to evaluate the security and efficacy in the lesions produced on the atrial wall by different irrigated catheters in an experimental model. We evaluated the anatomopathologic characteristics of the lesions produced by two different systems of irrigated tip catheters, with opened or closed circuit. METHODS: This study was performed in 16 pigs applying 60 sec radiofrequency pulses with three different energy levels (15, 25 y 50 Watts). Two different systems of radiofrequency ablation irrigated catheters were used, opened and closed. We used 4 pigs in which we performed ablation with a standard catheter as a control group. Under fluoroscopic guidance, catheters were placed on the high and low right atrial lateral wall, where lesions were produced. After 7 days, animals were sacrificed for anatomopathological study. RESULTS: A total of 27 lesions were performed with irrigated catheters (11 closed circuit and 16 opened) and 6 with standard catheters in the control group. We did not find significant differences in the lesion characteristics between the two different systems of irrigated tip catheter used, nevertheless lesions performed with the closed system were slightly greater. Th lesions produced with irrigated catheters were always superior in the control group. Transmurality in the free atrial wall is frequent with both systems. We did not see any perforation in the atrial wall. CONCLUSIONS: We did not find significant differences in the size of the lesions produced with the two systems of irrigated catheters used. These data from an experimental model can provide useful information for atrial tachycardia radiofrequency ablation procedures in humans.

Animals↗
PubMed2001

Piggyback implantation using the AMO array multifocal intraocular lens.

Piggyback intraocular lens (IOL) implantation allows refractive correction in cases in which the IOL power requirement exceeds that of the available lenses. By combining a piggyback technique with the use of a multifocal IOL, one can obtain the optical advantages of both, achieving high-quality visual acuity for distance and near vision and reducing the optical aberrations of extremely high-powered single IOLs. We report 5 hyperopic patients (6 eyes) who had phacoemulsification and in-the-bag implantation of 2 foldable IOLs in the bag, a silicone multifocal IOL placed in front of a silicone monofocal IOL. Good results were obtained in near and distance uncorrected visual acuities, and patient satisfaction was excellent in all cases. However, in 2 cases, the anteriorly placed IOL was exchanged because of incorrect power calculation. Piggyback IOL implantation with a multifocal lens appears to be a safe, efficient procedure and a good refractive solution.

Adult↗
PubMed2001

Influence of process variables in the ethanol pulping of olive tree trimmings.

A central composition design was developed to study the influence of process variables (temperature, pulping time and ethanol concentration) on the properties of the pulp produced (yield and holocellulose, alpha-cellulose and lignin contents) and the pH of the resulting wastewater, in the ethanol pulping of olive tree trimmings. The proposed equations reproduce the experimental results for the dependent variables with errors less than 5% for the holocellulose and alpha-cellulose contents, yield and wastewater pH, and less than 15% for the lignin content. Obtaining pulp with acceptably high yield (37.6%), high holocellulose and alpha-cellulose contents (above 88.8% and 46.9%, respectively), and low lignin contents (below 7.2%), entails operating at a pulping temperature of 200 degrees C, using an ethanol concentration of 75% and a pulping time of 60 min.

Biotechnology↗
PubMed2001

Eating disorders and altered eating behaviors in adolescents of normal weight in a Spanish city.

PURPOSE: To study the prevalence of altered eating behaviors or eating disorder-related behaviors among adolescents of normal weight that do not fulfill criteria for anorexia nervosa and bulimia nervosa. METHOD: Cross-sectional study by means of a self-completed questionnaire (School of Nutrition of Granada, Spain) and measurement of weight and height in a population of 491 schoolchildren aged 14-18 years. The statistical inferences and estimation of risk are based on comparison of proportions and means test, and the relative inequality of prevalences. RESULTS: Of 491 adolescents of normal weight, 9% (females 2:1) were following diets; 42% presented "recurrent episodes of binging" with the sensation of loss of self-control; and 41%% avoided specific types of food. Overall, 46.2% presented altered eating behavior. Factors significantly associated with this were the occurrence of periods of food abstinence and the use of purgatives [confidence interval 95% (CI 95%) prevalence ratio (PR) 1.41-2.02]. Compensatory behaviors were present in 33% of the adolescents, predominantly in females (CI 95% PR 1.79-3.07). The prevalences of abnormal eating behaviors were 16.3% for those related to anorexia (A-RB) and 17.1% for those related to bulimia (B-RB), with a clear predominance of females (2:1) and public education. There seems to be a greater aesthetic concern among those with B-RB and more worry about weight among those with A-RB. CONCLUSIONS: A high proportion of adolescents with abnormal eating behaviors and an altered perception of body fat may currently be diagnosed as having atypical eating disorder" (Diagnostic and Statistical Manual of Mental Disorders, Fourth Revision) considering that their body mass index was within normal range.

Adolescent↗
PubMed2001

Sequential therapy in advanced non-small-cell lung cancer with weekly paclitaxel followed by cisplatin-gemcitabine-vinorelbine. A phase II study.

OBJECTIVES: New effective therapies are needed to improve the outcome of patients with advanced non-small-cell lung cancer (NSCLC). The aim of this study was to assess the response rate and survival obtained with a sequential regimen of chemotherapy. PATIENTS AND METHODS: Patients with newly diagnosed stage IIIb-IV NSCLC were included. They all had measurable disease and a good performance status (0-2 in the Eastern Cooperative Oncology Group scale). Chemotherapy consisted of weekly paclitaxel 150 mg/m2 x 6, followed two weeks later by cisplatin 100 mg/m2 on day 1, gemcitabine 1,000 mg/m2 on days 1 and 14, and vinorelbine 25 mg/m2 on days 1 and 14 (CGV). CGV was administered every 28 days for a maximum of six courses. RESULTS: Fifty-two patients were included, 19 (37%) with stage IIIb and 33 (63%) with stage IV disease. After therapy with weekly paclitaxel. 29 partial responses were obtained (56%, 95% confidence interval (95% CI): 38%-67%), whereas 15 patients had stable disease (29%) and eight had a progression (15%). After CGV, there were four complete remissions (8%) and 24 partial responses (46%), for an overall response rate of 54% (95% CI: 37%-65%). Eight patients had stable disease (15%) and 16 had a progression (31%). No patient progressing after paclitaxel responded to CGV, whereas 5 out of 15 patients with stable disease reached a partial response with CGV (33%). On the contrary, 5 out of 29 patients with a partial response to paclitaxel progressed after CGV (17%). Median survival has not been reached after a median follow-up of 14 months. Median time to progression was nine months. Fifty-six percent of patients remain alive at one year. Two hundred eighty-nine courses of paclitaxel and 170 of CGV were given, with a median of 5.5 and 3.4 per patient, respectively (ranges 2-6 and 0-6. respectively). WHO grade 3-4 toxicities for paclitaxel were: neutropenia in two patients (4/) and peripheral neuropathy in five (10%). Two patients had allergic reactions requiring paclitaxel withdrawal, whereas four (8%) had hyperglycemia >250 mg/ml. Grade 3-4 toxicities for CGV were: neutropenia in ten patients (20%), peripheral neuropathy in six (12%), anemia in four (8%), nausea/vomiting in five (10%). thrombocytopenia in two (4%), and fatigue in four (8%). CONCLUSION: Our results suggest that sequential chemotherapy with weekly paclitaxel followed by CGV is highly active in patients with advanced NSCLC and has an acceptable toxicity. This schedule deserves further evaluation in a phase III study.

Adult↗
PubMed2001

Immunocytochemical location of endogenous cytokinins in buds of kiwifruit (Actinidia deliciosa) during the first hours of in vitro culture.

Post-embedding immunocytochemical techniques using peroxidase-antiperoxidase as markers for light microscopy or immunoglobulin G-gold for electron microscopy respectively were used for the localization of cytokinins [9-beta-D-ribofuranosil-N6-(delta2-isopentenil) adenina ([9R]iP), 9-beta-D-ribofuranosyl-zeatin ([9R]Z) and 9-beta-D-ribofuranosyl-dihydrozeatin ([9R](diH)Z)] in kiwifruit (Actinidia deliciosa) meristematic cells of the second nodal segment. Immunolocation at the cellular level was carried out in cells from explants grown during 16 and 72 h in liquid medium. Subcellular immunolocalization was performed in cells from explants grown for 35 d on agar solidified-medium and for 30 min, 4 and 16 h in liquid medium with cellulose plugs as explant support. Taken as a whole, the results obtained for Actinidia deliciosa show that the studied cytokinins change their location during the culture period, although they can always be found to a greater or lesser extent in the nucleus and the cytoplasm. For instance, [9R]Z appears in the cytoplasm and in the nucleus during the first hours of culture and later is the only one that appears located mainly in nucleus. On the other hand, [9R](diH)Z changes from being predominantly located in the nucleus to practically appearing only in the cytoplasm at the end of the culture period. [9R]iP is principally found up to 4 h of culture in the cytoplasm, and at 16 h is evenly distributed in all the subcellular compartments except in the chloroplast. The existence of a large amount of cytokinins in the nucleus during the first hours of culture compared with the immunolabelling density at 35 d is probably due to the activation of cell cycle mechanisms leading to organogenic development at the beginning of culture.

Actinidia↗
PubMed2001

Allergy to grape: a case report.

We report a case of a 5-year-old child who suffered an oral allergy syndrome and lip angiedema after eating grapes. We obtained a positive prick test with commercial grape extract and a positive prick-by-prick test with pulp and peel of fresh white grape (Moscatel variety) and pulp and peel of blue grape. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis followed by immunoblotting revealed specific immunoglobulin E (IgE) antibodies in the patient's serum against a 94,000 molecular-weight antigenic band. Lip open challenge was positive.

Angioedema↗
PubMed2001

Thermally induced conformational changes in horseradish peroxidase.

Detailed differential scanning calorimetry (DSC), steady-state tryptophan fluorescence and far-UV and visible CD studies, together with enzymatic assays, were carried out to monitor the thermal denaturation of horseradish peroxidase isoenzyme c (HRPc) at pH 3.0. The spectral parameters were complementary to the highly sensitive but integral method of DSC. Thus, changes in far-UV CD corresponded to changes in the overall secondary structure of the enzyme, while that in the Soret region, as well as changes in intrinsic tryptophan fluorescence emission, corresponded to changes in the tertiary structure of the enzyme. The results, supported by data about changes in enzymatic activity with temperature, show that thermally induced transitions for peroxidase are irreversible and strongly dependent upon the scan rate, suggesting that denaturation is under kinetic control. It is shown that the process of HRPc denaturation can be interpreted with sufficient accuracy in terms of the simple kinetic scheme N -->k D where k is a first-order kinetic constant that changes with temperature, as given by the Arrhenius equation; N is the native state, and D is the denatured state. On the basis of this model, the parameters of the Arrhenius equation were calculated.

Calorimetry↗
PubMed2001

The effect of fibroblast growth factor and transforming growth factor-beta on porcine chondrocytes and tissue-engineered autologous elastic cartilage.

Elastic cartilage responds mitogenically in vitro to transforming growth factor-beta (TGF-beta) and basic fibroblast growth factor (basic FGF). We studied the effects of these growth factors separately or in a combination on porcine auricular chondrocytes in vitro and on the autologous elastic cartilage produced. Cells were harvested from the elastic auricular cartilage of 16- to 18-kg Yorkshire swine. Viability and quantification of the cells was determined. Cells were plated at equal concentration and studied in vitro in one of four identical media environments except for the growth factors: Group I contained Ham's F-12 with supplements but no growth factors, Group II also contained basic-FGF, Group III also contained TGF-beta, and Group IV also contained a combination of both growth factors. After 3 weeks in vitro, the cells were chemically dissociated with 0.25% trypsin. Cell suspensions composed of 3 x 10(7) cells/cc in 30% Pluronic F-127/Ham's F-12 were injected subcutaneously. Implants were harvested at 6, 8, 10, and 12 weeks of in vivo culture and then were examined with histologic stains. After 3 weeks of in vitro culture the total number of cells was as follows: Group I, 1.8 x 10(8); Group II, 3.5 x 10(8); Group III, 1.3 x 10(8); Group IV, 2.5 x 10(8). After 8 weeks of in vivo autologous implantation, the average weight (g) and volume (cm3) of each group was as follows: Group I, 0.7 g/0.15 cm3; Group II, 1.5 g/0.8 cm3; Group III, 0.6 g/0.1 cm3; Group IV, 1.2 g/0.3 cm3. Histologically, Groups I, II, and IV generated cartilage similar to native elastic cartilage, but Group III specimens demonstrated fibrous tissue ingrowth. Basic FGF produced the most positive enhancement on the quantity and quality of autologous tissue engineered elastic cartilage produced in this porcine model both in vitro and in vivo.

Animals↗
PubMed2001

Transmission trials with a support system for the treatment of cardiac arrest outside hospital.

A mobile electrocardiogram (ECG) transmission system was developed which could transmit single-lead ECG data via GSM mobile telephony. Ambulance transmission trials comprised a total of 72 communications, of which 94% were successful. The system was able to redial up to a predetermined number of times until the GSM call was re-established (during the trials this value was set to five). The average number of GSM call tries was 1.3 per connection. The mean time required to establish a connection was 45 s; the minimum was 34 s, when only one attempt was needed to establish a GSM call. The average duration of ECG transmission between communication breakdowns was 5 min 12 s. When a link breakdown occurred, the user had to wait for an average of only 42 s to continue monitoring the signal.

Electrocardiography↗
PubMed2001

[The cells of accessory immune system].

In the Reticulo-Endothelial System (RES), named at present Accessory Immune System (AIS), two chief groups of cells can be recognized: 1--Antigen-presenting cells: Dendritic cells 2--Antigen-processing cells: Macrophages (or Histiocytic cell) True malignant Langerhans cell neoplasm has not been yet clearly demonstrated. Finally, it is important to note that marcrophages and dentritic cells are commonly observed as relative cells in numerous malignant tumors (carcinomas, sarcomas, lymphomas, etc) However, their precise role has yet to be determined.

Animals↗