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Biomedical subjects

A Varela

Publications and source records attributed to A Varela.

At least 55 records · Page 3Linked to original sources
PubMed1999

[Lung transplantation in cystic fibrosis. The results of the Clínica Puerta de Hierro (Madrid) and the Hospital La Fe (Valencia)].

UNLABELLED: Retrospective analysis of cystic fibrosis patients who underwent pulmonary transplantation at Clínica Puerta de Hierro, Madrid, and at Hospital La Fe, Valencia. Since the beginning of the programme and until March 1998, a total of 63 patients with cystic fibrosis were studied. Among transplanted patients, 18 were males and 16 females, with a mean age of 18.9 years. All patients underwent sequential bilateral pulmonary transplantation. After transplantation, the most common complication was bacterial pneumonia which affected all patients. Six patients had dehiscence or stenosis of the bronchial suture. Other specific complications of this condition by frequency were intestinal obstruction and diabetes mellitus. Six patients developed obliterans bronchiolitis and one of them underwent a repeat transplantation. Three out of the 34 patients died, and the likelihood of survival after one and three years was 94%. Respiratory function tests and PaO2 peaked at sixth post-transplantation month. CONCLUSION: Pulmonary transplantation is a therapeutic option to be considered for the patient with cystic fibrosis and severe involvement of his/her pulmonary disease.

Adolescent↗
PubMed1999

Lack of protective effects of adenosine on the hypoxic and reoxygenated atria and ventricular strips of the rat.

The aim of the investigation was to assess whether adenosine would ameliorate the hypoxic-induced disturbances of the isolated atria and ventricular strips from fed and 24 h fasted rats. Adenosine 100-50 microM exerted negative inotropic and chronotropic effects on the aerobic atria whereas 10 microM was ineffective. During hypoxia the atria underwent a decline of the peak developed tension and pacemaker frequency. Adenosine 50 microM was detrimental for the performance of hypoxic atria whereas a 10 microM neither affected the fall of peak tension nor the post-hypoxic recovery. Adenosine 100 microM did not affect the peak developed tension of the aerobic ventricular strips. Under hypoxia the ventricular strips from fed and fasted rats exhibited a pronounced depression of their peak developed tension together with the development of a strong contracture and a partial recovery after reoxygenation, which attained a similar extent in both nutritional states. Lactate output during hypoxia was lower in the group of fasted rats. Adenosine 100 microM did not exhibit any effect on the ventricular functions and glycolytic activity in both experimental groups. Results suggests that adenosine has no beneficial effects on rat isolated atria and ventricular strips in hypoxic conditions

Adenosine↗
PubMed1999

[Seroprevalence of helicobacter pylori infection in the republic of Argentina: influence of age, sex, socioeconomic level, geographical area, and health infrastructure. Multicenter study by the Club Argentino del Estomago y Duodeno].

Helicobacter pylori (Hp) infection affects almost half of the world population, it is almost a pandemia, and has been associated to poverty in underdeveloped countries. The Club Argentino del Estómago y Duodeno decided to fulfill the lack of information upon this subject in Argentina designing a seroprevalence, multicentric, prospective study performed in voluntary adults donors in blood banks and in children seen during normal growth controls. Seven hundred and nineteen individuals were evaluated, 645 of them were included: 178 children (age 0-18 years) and 467 adults. In all cases a serological IgG Hp test (Flex-Pack Abbott) was performed and an epidemiological questionnaire was completed by a physician. General prevalence of Hp infection was 44.8% of individuals. In the paediatric population prevalence was 15.7% and in adults 55.9%. The highest prevalence was observed in the fifth decade: 64%. In concordance with other similar studies carried out in different countries, we may conclude that the risk of acquisition of Hp infection is directly related to age, area of residence, social-economical status, sanitary facilities, and educational level reached. Even though the prevalence of Hp infection in Argentina is intermediate between highly developed and underdeveloped countries, the number of people infected is very high and the incidence of Hp-associated pathologies in the future represents a formidable task for gastroenterologists and sanitary authorities.

Adolescent↗
PubMed1999

Influence of moderate cooling (37 degrees C-25 degrees C) on the reactivity of isolated rat tail artery.

The aim of the investigation was to examine the effects of cooling on the tail artery regarding the scarceness of such studies in spite of the essential thermoregulatory role played by this vessel. Segments of the proximal portion were suspended isometrically in medium containing 1.25 mM Ca. Lowering the temperature to 25 degrees C increased the sensitivity and maximum strength of the adrenaline concentration-effect curves. These changes were reversed by warming back to 37 degrees C. Cocaine attenuated the increase of sensitivity without changing the increase of the maximum response. Either the sensitivity and strength of the responses to phenylephrine and serotonin were increased by cooling. Clonidine evoked weak contractions in 18 out of 38 experiments. After cooling, the responses persisted only in 7 arteries and the strength was almost halved. Responses to field electric stimulation at 25 degrees C exhibited a pronounced increase of strength and a small increase of sensitivity. -log Kb for prazosin against adrenaline was increased by cooling (8.7 and 9.1 at 37 degrees C and 25 degrees C, P < 0.01). After partial receptor inactivation using phenoxybenzamine, the dissociation-constant (KA) indicated a moderate affinity for phenylephrine that was not changed by cooling (4.1 and 4.2 x 10(-6) at 37 degrees and 25 degrees C respectively). Receptor reserve and occupancy at EC50 also remained unchanged at 25 degrees C. It can be concluded that: 1) cooling increases the tail artery reactivity, partly as a consequence of the inhibition of adrenergic neuronal uptake; 2) responsiveness to alpha 2-agonists is not involved in the effects of cooling whereas the role of alpha 1-adrenoceptor could not be properly clarified; 3) cooling may facilitate some steps of the contractile activation beyond the agonist-receptor interaction.

Adrenergic alpha-Agonists↗
PubMed1998

Reduction of QT and QTc dispersion during long-term treatment of systemic hypertension with enalapril.

We report, in conjunction with other findings, the evolution of the dispersion of QT and QTc in patients who for the last 7 years have been treated with enalapril for systemic hypertension with left ventricular (LV) hypertrophy. Twenty-four essential hypertensive patients who had received no previous treatment took enalapril (20 mg twice daily) for 7 years. In a pretreatment placebo phase and 8 weeks and 1, 3, 5, 6, and 7 years after the start of therapy, cardiovascular parameters were determined by two-dimensional guided M-mode echocardiography, and the QT interval and corrected QT interval (QTc) and their dispersions were obtained from amplified standard 12-lead electrocardiograms. Therapy rapidly reduced blood pressure (BP) from 156/105 mm Hg to normal values; at 7-year follow-up, BP was 130/84 mm Hg (p <0.001 with respect to the placebo phase). LV mass index decreased progressively until at 5-year follow-up the reduction had reached 39% (p <0.001), after which neither LV mass index nor any structural parameter underwent any further significant change. LV pump function was also significantly better after 7 years of treatment. During this time, QT and QTc decreased significantly, as did the dispersion of both QT (from 61+/-21 to 37+/-14 ms) and QTc (from 67+/-27 to 41+/-16 ms). We conclude that long-term enalapril treatment of hypertensive patients with LV hypertrophy not only induces marked regression of LV mass and improved LV systolic function, but also reduces the dispersions of QT and QTc, which probably reduces the likelihood of ventricular arrhythmias and improves prognosis.

Adult↗
PubMed1998

[Survival of lung transplant at the Puerta de Hierro Clinic].

The objective of this study was to analyze patient survival after lung transplants performed at the Puerta de Hierro clinic in Madrid (Spain) between 1991 and 1996. Survival probability was 65% after one year and 50% after three years. We found no significant differences in survival related to sex or type of transplant. Early survival tended to be higher for the last two years analyzed (71%) than for the first two (55%) (p < 0.00001). The rate was 100% for patients with cystic fibrosis and 0% for pulmonary hypertension and lymphangiomyomatosis. Short- and medium-term lung function results were good in surviving patients who did not develop obliterating bronchiolitis. We conclude that actuarial survival after lung transplant in our program is comparable to that reported in the literature. There are no significant differences related to sex, type of transplant or period. Survival varies greatly, however, depending on disease.

Adolescent↗
PubMed1998

Increase of C-reactive protein and decrease of surfactant protein A in surfactant after lung transplantation.

In this study, we asked whether the serum acute-phase protein C-reactive protein (CRP) increased in large surfactant aggregates after lung transplantation and analyzed the changes in composition and interfacial adsorption activity of those aggregates. Single left lung transplantation was performed in weight-matched pairs of dogs. A double-lung block from the donor animal was flushed with either modified Euro-Collins solution (EC) (n = 6) or University of Wisconsin solution (UW) (n = 6) at 4 degrees C followed by immersion in cold EC or UW for 22 h. The left donor lung was transplanted. The recipient dog was then reperfused for 4.5 h. Irrespective of the preservation fluid, gas exchanged was impaired in the transplanted lung after 4.5 h of reperfusion. Large surfactant aggregates obtained from this lung showed reduced ability to rapidly adsorb to an air-liquid interface. Phospholipid (PL) content and PL composition of surfactant from lung transplants was similar to that of the control lungs. However, the content of surfactant protein A decreased after reperfusion. In addition, Western blot analyses showed that levels of CRP increased in surfactant from transplanted but not from donor lungs. The addition of human CRP to control surfactant (CRP:PL weight ratio, 0.01:1) caused a decrease of surfactant adsorption. We conclude that the impairment of adsorption facilities of surfactant from transplanted lungs may be correlated with decreased levels of surfactant protein A and increased levels of CRP. The presence of elevated levels of CRP in bronchoalveolar lavage could be a very sensitive marker of lung injury.

Adsorption↗
PubMed1998

[Correlation between 99m Tc-tetrofosmin uptake and P-glycoprotein expression in non-small-cell lung cancer].

UNLABELLED: We used thoracic SPECT to study the 99mTc-tetrofosmin (TF) uptake in patients with non-small-cell-lung-carcinoma (NSCLC). The results were compared with the percentage of P-glycoprotein (Pgp) found in flow cytometric analysis (FC) of samples of surgically-resected tumor tissue. MATERIAL AND METHODS: A total of 21 patients with NSCLC were studied by means 99mTC-TF and thoracic SPECT. Image analysis included the determination of the TF uptake rate in the lung mass with respect to that of healthy tissue of the contralateral lung. These rates were compared with the percentage of Pgp expression according to FC. FC analysis was also carried out in 16 samples of healthy lung tissue obtained from the patients. RESULTS: In healthy lung tissue, the mean Pgp expression according to FC was 4.58 +/- 1.87%. The cutoff value used to differentiate between Pgp positive and Pgp negative tumors was considered to be the mean plus two standard deviations (8.32). The Pgp-positive tumors (> 8.32%) presented significantly lower uptake levels (1.28 +/- 0.39) than the Pgp-negative lesions (1.66 +/- 0.33) (p = 0.029). CONCLUSIONS: There is a inverse correlation between the Pgp expression as determined by FC analysis and 99mTc-TF in NSCLC. Thus, this radiopharmaceutical provides rapid and non-invasive information on Pgp expression in these lesions.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1997

Effects of fasting, hypoxia, methylpalmoxirate and oxfenicine on the tissue-levels of long-chain acyl CoA and acylcarnitine in the rat atria.

During hypoxia the atria from fasted rats exhibit a faster decline in the pacemaker and contractile activities than those from fed rats. Oxfenicine and methylpalmoxirate, inhibitors of carnitine palmitoyltransferase 1 (CPT 1), ameliorate these disturbances. Since the fasted rat atria have greater triacylglycerol stores and a faster lipolysis, and CPT 1 funnels fatty acid into beta-oxidation, the effects of fasting could be ascribed to the accumulation of amphipathic metabolites such as long-chain acyl CoA (LCCoA) and long-chain acylcarnitine (LCCa). Hence, this investigation aimed to assess whether the levels of these metabolites correlate with the effects of fasting and CPT 1 inhibitors. At the end of the prehypoxic equilibration period the fasted rat atria had a 6.5-fold greater content of LCCa than those of the fed rats and methylpalmoxirate impeded the increase. During hypoxia the LCCoA content increased 9-fold in the fasted rat atria, LCCa levels were 3.6-fold greater in the fasted than in the fed group, and free-CoA and free-carnitine showed a significant fall. The increases of LCCoA and LCCa as well as the fall in free-CoA were abolished by both inhibitors. The decrease of free-carnitine was impeded by methylpalmoxirate, but oxfenicine unexpectedly decreased its concentration in both nutritional groups. These data suggest that: (1) the atrial CPT 1 activity is enhanced during fasting, (2) in the hypoxic atria levels of LCCoA and LCCa were closely correlated with the noxious effects of fasting and the amelioration effected by CPT 1 inhibitors, and (3) the effects of amphipathic metabolites during oxygen deprivation can be attenuated by pharmacological interventions.

Acyl Coenzyme A↗
PubMed1997

Improved distribution of pulmonary flush solution to the tracheobronchial wall in pulmonary transplantation.

This report describes the experimental results obtained with conventional (pulmonary artery, PA) flushing versus retrograde perfusion (via left atrium, LA) using 99mTc-labeled macroaggregated albumin (MAA-99mTc) to ascertain the distribution throughout the tracheobronchial (TB) tree in 10 Large-White pigs. Lung preservation was achieved with 4 degrees C Euro-Collins solution (60 ml/kg) instilled via PA (n = 5) or LA (n = 5). Simultaneously, MAA-99mTc was given using the same respective route and the isotope uptake quantified at different TB levels after heart-lung block harvest and dissection of all tissue adjacent to TB: proximal and distal trachea and right and left main bronchi. Retrograde distribution resulted in a significantly higher 99mTc count compared to the PA route (p < 0.01).

Animals↗
PubMed1997

Unravelling the genetics of deafness.

Hearing-impaired mouse mutants not only are good models for human hereditary deafness, but also are extremely useful for understanding the molecular basis of the cochlear defect. We describe here how we identified the gene responsible for the deafness and vestibular defects in the shaker-1 mouse mutant as a myosin VII gene. Three different mutations, all causing the same phenotype in different lines of mouse, were found, providing good evidence that we had, indeed, found the correct gene. The same gene was subsequently found to be involved in Usher's syndrome type 1B, which features deafness, vestibular dysfunction, and progressive retinitis pigmentosa. The myosin VII gene is expressed in sensory hair cells, but not in supporting cells or neurons. We are investigating the role of myosin VII in hair cell development and function. Analysis of the different mutant stocks suggests it has at least two functions. First it is involved in the development and maintenance of the stereocilia bundle. Second, it has a role in inner hair cell function. No evidence of retinal degeneration like that in Usher's syndrome has been found in the shaker-1 mutants so far studied. The benefits of understanding the function of the gene for families with Usher's type 1B are discussed. This gene is the first to be identified as causing the most common type of disorder in human hearing impairment, neuroepithelial abnormalities, and suggests a new class of candidate genes for involvement in such defects.

Animals↗
PubMed1997

Effect of an aerobic training on magnesium, trace elements and antioxidant systems in a Down syndrome population.

The aim of the present study was to determine the effect of an aerobic training on plasma and red blood cells' levels of magnesium, copper, selenium and zinc and on some oxidative stress parameters in a Down syndrome (DS) sample population. Sixteen young male adults with DS participated in the protocol. Among them, eight were randomly assigned to the control group and the remaining eight participated in a 16 week training programme consisting of 10 min warm-up followed by an aerobic session at a work intensity of 60 to 75 per cent of VO2 peak lasting from 15 to 25 min, increasing 5 min every 5 weeks and by a 5 min cool-down period, 3 days/week. Blood was withdrawn by butterfly from antecubital vein of each subject at fast, 2 days before the beginning of the programme and 2 days after its ending. Before the training period, when comparing the two groups, no significant differences were observed in the evaluated parameters. However, when comparing with a healthy population, red blood cells magnesium and plasma and red blood cells selenium mean values were low in both groups and mean SOD activity was 1.4 times higher. After the protocol the mean values of the minerals studied did not show significant differences between groups except for plasma zinc that was lower (p = 0.029) in the trained group. Plasma TBARS increase was significant in the trained group (p = 0.034) but not in the control group and plasma GSH of the trained group had a significantly higher increase than the control group (p = 0.003). The levels of plasma TBARS after the training programme that were inversely correlated with red blood cells GSSG levels (p = 0.023) and the higher increase of plasma GSH mean values observed, may be explained by the effect of the exercise period on the peroxidation and reduction of glutathione and also on the synthesis and efflux of GSH. Red blood cells magnesium levels remained low after the training programme which is in accordance with other studies. Plasma zinc decreased during the programme could be related to the activated expression of antioxidant mechanisms after the training.

Adolescent↗