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Biomedical subjects

A Baeza

Publications and source records attributed to A Baeza.

36 records · Page 2Linked to original sources
PubMed1995

Factors determining the radioactivity levels of waters in the province of Cáceres (Spain).

In an extensive study of different types of water in the province of Cáceres (Spain) in order to determine their total alpha- and total beta-radioactivity contents, several factors were found to have a decisive influence on their radioactivity levels. Thus, parameters such as total hardness and pH can be determinative according to the lithological type of the aquifer or according to the subterranean or surface origin of the hydrological resource. Waters from classic lithologies, or originating from a well, possess above-average radioactivity indices, surpassing in numerous cases the indicative levels set by current Spanish legislation. In contrast, surface waters from rivers, in practically all cases, possess below-average radioactivity indices.

Fresh Water↗
PubMed1994

[Intrathyroidal lymphocytes in autoimmune thyroid diseases].

Aiming to assess the autoimmune origin of certain thyroid diseases, we studied the phenotypic composition and the ability of intrathyroidal lymphocytes to a re-induce HLA-DR expression on autologous thyrocytes coming from patients with graves's disease, nodular goiter and papillary thyroid carcinoma. Lymphocytes coming only from graves's disease patients were capable of reinduce HLA-DR expression on autologous thyrocytes (24.1 +/- 13.6 vs 1.5 +/- 2.54% in nodular goiter and carcinoma), as interferon gamma did (17.4 +/- 8.34%). Phenotypic characterization showed a significant decrease of T-CD3 (total lymphocytes) and T-CD4 (helper) in lymphocytes coming from patients with nodular goiter and carcinoma, and a marked reduction of T-CD8 (suppressor) in lymphocytes coming from patients with graves disease. Thus the T-CD4/T-CD8 ratio varies according to the etiology of the thyroidal disease. The lack of suppressor activity would explain why cells coming only from patients with graves disease, show marked HLA-DR expression. These findings give little support to the autoimmune origin hypothesis for nodular goiter and thyroid carcinoma.

Autoimmune Diseases↗
PubMed1993

[Lack of in vitro effect of antithyroid drugs upon peroxidase antigen expression in autoimmune thyroid disease].

The aim of this study is to determine whether antithyroid drugs (ATD) act via inhibiting thyroid hormone synthesis or by interfering with the immune process which leads to autoimmune disease. Previously we had demonstrated that ATD do not affect HLA-DR and TPO antigen expressions induced by appropriate stimulus in normal thyrocytes, so we decided to study what happens when the same experiments are performed using autoimmune thyrocytes. Cultured thyroid tissue from patients operated on for Graves' Disease or Hashimoto's Thyroiditis were stimulated with TSH or TBII alone or associated with ATD; TPO antigen expression was evaluated by the Cytotoxicity Assay using human monoclonal antiTPO. When autoimmune thyrocytes were cultured and no stimulus was used or with the addition of MMI or PTU alone, very low values of TPO expression were noted (8.6 +/- 6.7, 5.0 +/- 7.1 and 4.2% +/- 2.3% respectively); if they were stimulated with TSH or TBII, a sharp rise of TPO antigen expression was detected (54.4 +/- 23.3 and 62.6 +/- 16.5%), these figures being significantly different from unstimulated cells (p < 0.001). If both stimulus were used associated with ATD, the high TPO antigen expression was unaffected. It is concluded that, at least in vitro, ATD have no effect upon induced-antigen expression in autoimmune thyrocytes. Since they do not alter antigen presentation, a primary step in the immune process, it is difficult to accept that their mechanism of action is through interference with the immune response.

Antithyroid Agents↗
PubMed1991

Rapid preoperative preparation in hyperthyroidism.

OBJECTIVE: We have evaluated an alternative method of preparation of hyperthyroid patients for surgery, using betamethasone, iopanoic acid and propranolol. DESIGN: Betamethasone (0.5 mg every 6 hours), iopanoic acid (500 mg every 6 hours) and propranolol (40 mg every 8 hours) were given orally for 5 days; thyroidectomy was performed on the 6th day. We analysed patient acceptability, clinical and hormonal effects, ease of surgery and final outcome. PATIENTS: Thirteen females and 1 male, aged 16-59 years, ten with diffuse goitre and four with nodular goitre were submitted to subtotal thyroidectomy because antithyroid drugs had failed to control thyrotoxicosis or because hyperthyroidism coexisted with other conditions (pregnancy, hypertensive disease). MEASUREMENTS: Daily clinical assessments were made together with T3, T4 and rT3 serum concentrations before and while on drug treatment, during the surgical procedure and post-operatively. RESULTS: Daily assessment showed progressive clinical improvement so that on day 5 the patients were considered clinically euthyroid. Serum levels of T3 (mean +/- SD) showed significant decrease (by 38.2 +/- 24.9%, P less than 0.01) as early as 24 hours after medication was started, reaching almost euthyroid levels on day 3; on the day of operation T3 had diminished by 64.5 +/- 16.6% (P less than 0.0001). Serum T4 concentration showed a slight but significant decrement only from day 4 on and never reached euthyroid levels. Serum rT3 values exhibited a brisk increment at 24 hours (+333 +/- 194%, P less than 0.0001) and remained elevated between 8 and 10 nmol/l until medication was stopped. Drug tolerance was considered as excellent since no serious side-effects were noted, even in pregnant patients. There were no anaesthetic incidents or postoperative complications and patients were discharged 48-72 hours after operation. The final outcome has been satisfactory and pregnant patients continued their pregnancies without incident, bearing normal children. CONCLUSIONS: Pharmacological combination of betamethasone, iopanoic acid and propranolol has proved to be safe and effective and is of low cost. Provided there is adequate supervision of the patients, it may be used in patients requiring urgent thyroidectomy or in those who for reasons of non-compliance need a short preoperative regime.

Adolescent↗
PubMed1989

[Ultrasonics in the diagnosis of choledocholithiasis].

The value of ultrasound in the diagnosis of choledocholithiasis is controversial, sensitivity figures ranging from 22 to 75%. We correlated the ultrasound study with operative findings in 38 patients. A diagnosis of common bile duct stone was made upon finding an echogenic image with or without acoustic shadow in the common bile duct; no attention was paid to the dilatation of the biliary tree. The sensitivity was 68% and the positive predictive value was 85%. Therefore, our results approach the highest reported figures for the value of this diagnostic technique.

Evaluation Studies as Topic↗
PubMed1988

Radiocesium concentration in migratory birds wintering in Spain after the Chernobyl accident.

Levels of 137Cs and 134Cs resulting from the Chernobyl nuclear accident were studied in 195 birds that winter in two regions of Spain. Only five of the 12 species examined were contaminated. The average values for 137Cs vary between 1.6 and 41 Bq kg-1 fresh. In particular, the contamination for song-thrushes (Turdus philomelos) are compared between the regions of Extremadura and Valencia, 350 km east of Extremadura at the same latitude. The results show that the contamination of birds wintering in Spain decreases from east to west. The whole-body dose commitment for humans consuming these contaminated birds was calculated. The values are well below the established ICRP guideline.

Accidents↗
PubMed1986

[18 years after a penetrating heart injury: follow-up].

This report presents a case of penetrating chest trauma leading to pericardial tamponade and ventricular septum defect successfully resuscitated by surgery in 1968 in an 11-year-old boy. 10 years later a first-size calcified hematoma was removed. However the 30% left to right intracardiac shunt flow as established by complete heart catheterization prior to surgery was not corrected. Non-invasive methods were used to assess cardiac function 18 years after the initial event including physical examination, chest X-ray, thoracic computer tomography, ECG, 24 h Holter monitoring and exercise testing, combined with myocardial scintigraphy and radionuclide angiography and echocardiographic techniques using the transthoracic and the transoesophageal approach. The diagnostic value of echocardiographic examinations is emphasized with special reference to contrast- and Doppler-echocardiography including the color-coded Doppler-flow-imaging technique.

Adult↗
PubMedDate not supplied

Spectrometric determination of low activities of gamma emitters in water samples.

Two variants of the ISO 10703:1997 procedure were developed: (i) the partial substitution of the reagents, thereby reducing the mass of the dry residue by a factor of 2; (ii) preparation of two gamma spectrometry sources by selectively precipitating the radioiodines onto one, and the rest of the radioactive cations onto the other. In variant (ii) the time required to prepare a 131I source from 20 l of water is 2.5 days, and the detection limit is 0.9 mBq/l.

Journal Article↗
PubMedDate not supplied

Analytical model for evaluating lateral capture efficiencies in surface treatment tanks.

A pilot scale installation 1.8 m long and 1.6 m wide was designed to simulate a surface treatment tank incorporating a lateral capture system and a distribution network that permits the surface emission of tracer (SF6). The capture efficiency, ET, was determined as a function of the specific capture flow qc, m3/sm2, for three tank lengths, L, (1.2, 1.53, and 1.8 m) and several temperatures, T, from ambient to 95 degrees C, keeping the surrounding air velocity low (v < or = 0.1 m/sec). The data showed a satisfactory fit to a model that related capture efficiency with two exponential functions: the first dependent on the ratio capture velocity/air velocity in the vicinity of the tank, and the second on the ratio capture velocity/velocity of rising drafts provoked by the temperature of the tank.

Air Movements↗
PubMedDate not supplied

Methodologies for determining capture efficiencies in surface treatment tanks.

Methodologies are proposed for determining capture efficiencies in the ventilation systems of surface treatment tanks, using test-scale equipment. The equipment, which incorporates a lateral and push-pull ventilation system, can measure and control the variables of interest because it incorporates a tracer gas generator (sulfur hexafluoride, the concentration of which is measured by infrared spectrometer). The experimental methodologies described determine total efficiency (when the tracer is emitted uniformly from the whole surface of the tank) and the so-called transversal linear efficiency (when the tracer is emitted linearly through a perforated tube situated over the tank, parallel to the exhaust hood face). The analytical and graphical relationships that can be are established between the two efficiencies make it possible to detect where the emissions not captured by the ventilation system are produced (i.e., losses to the outside). At the same time, such losses can be quantified. Several experiments, results of which are analyzed by the methods described, are included.

Air Pollutants↗
PubMedDate not supplied

Visualization of airflows in push-pull ventilation systems applied to surface treatment tanks.

A pilot installation was designed that simulates a surface treatment tank fitted with a push-pull ventilation system. The installation contained elements for measuring and controlling the operational variables (flow rate and tank temperature) and smoke generating equipment for injecting smoke through the holes of the push unit and from the tank surface. Visual observation and video recording of the flows involved meant it was possible to follow the qualitative behavior of the push flow rate along the tank surface and to identify any emissions not captured by the exhaust system. It was possible to differentiate the initial semifree push curtain, its impact with the tank surface, the wall jet that moved toward the exhaust, and its entrance into the exhaust. The methodology proposed is complemented by a quantitative technique for measuring the efficiency, using sulfur hexafluoride as tracer, which permits the causes and location of losses in the ventilation system to be determined.

Air Movements↗
PubMedDate not supplied

[Acquirement of the Spanish vocabulary among rural and urban students of the 9th region].

In order to test the assumption that rural children from the Araucanía region at southern Chile start school with significant handicaps in the acquirement of the spanish vocabulary when compared with their urban peers, the Peabody Picture Vocabulary Test (PPVT, spanish version) was used to compare a first group including all those children attending third grade at a public school from a low socio economic level neighborhood of the city of Temuco, Chile (n = 44, age average 9.01 years, s = 0.51) against a second group including all those children attending the same grade at three public schools from the rural areas surrounding the same city (n = 37, age average 9.07 years, s = 0.52). Previously, 19 children aged 3 to 5 years were tested both with the PPVT and with the chilean instrument for the measurement of development at the age group (TEPSI). Both scores show a positive correlation (r = 0.64, p = 0.05). Average scores for the PPVT among rural children were lower than among urban children (64.07, s = 11.36 against 103.05, s = 10.99, p = less than 0.01). In a second stage, 39 children attending 7th grade at the urban school (age average 13.61 years, s = 0.64) and 27 children of the same grade from the rural schools (age average 13.69 years, s = 0.69) were tested with the same instrument.(ABSTRACT TRUNCATED AT 250 WORDS)

Acculturation↗