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Biomedical subjects

A Torralba

Publications and source records attributed to A Torralba.

At least 19 recordsLinked to original sources
PubMed2000

Heart transplantation: influence of the surgical technique on sinus function.

This study analyzes the influence of the surgical technique on the development of sinus dysfunction. Cycle length, corrected sinus node recovery time, and sinoatrial conduction time were determined in 4 groups of dogs under the following conditions: group 1, controls; group 2, subjected to heterotopic heart transplantation with conservation of atrial anatomy; group 3, subjected to orthotopic heart transplantation by using a standard technique; and group 4, treated as in group 3, but with an ischemic time of 24 hours. The cycle length was prolonged in all the treated groups when compared with the controls (P < .01), an effect attributed to the disconnection of the autonomic nervous system during the transplantation procedure. The corrected sinus node recovery time and sinoatrial conduction time were significantly longer in all the animals in groups 3 and 4 when compared with those of groups 1 and 2 (P < .01); however, there were no significant differences between groups 3 and 4 or between groups 1 and 2. These results suggest that the atrial anatomy play a more relevant role than the ischemic time in the origin of sinus dysfunction occurring after orthotopic heart transplantation.

Animals↗
PubMed1998

Electrophysiologic assessment of calcium channel blockers in transplanted hearts: an experimental study.

The effects of calcium channel blockers on automaticity, conduction, and refractoriness were studied in a model of heterotopic heart transplantation in dogs, which combined an innervated heart (recipient) and a denervated one (donor). Following the surgical procedure, 0.2 mg/kg verapamil (n = 10), 0.15 mg/kg diltiazem (n = 10), or 5 microg/kg + 30 microg/kg/h nifedipine (n = 10) was administered intravenously. In basal situation and after drug administration, each heart was assessed for AV interval, cycle length, sinoatrial conduction time, atrioventricular node antegrade block point, and atrioventricular node and ventricular refractory periods; electrocardiographic PR and QT intervals and QRS complexes; systemic arterial, pulmonary artery, central venous, and pulmonary capillary wedge pressures; and cardiac output. The depressor effects of these calcium channel blockers on automaticity, refractoriness, and conduction were more intense in the transplanted hearts, very possibly because of the absence of adrenergic reflexes mediated by the autonomic nervous system; in particular, verapamil produced a great depression of sinus automaticity in a large number of cases.

Animals↗
PubMed1998

Cape Town solution in prolonged myocardial preservation: structural and ultrastructural study.

This study deals with myocardial preservation after 24 hours of continuous, hypothermic and oxygenated perfusion with Cape Town (CT) solution, focusing on the morphological changes produced by preservation and reperfusion, and their possible relationship to the composition of the solution and the immediate hemodynamic findings after orthotopic heart transplantation in dogs. After preservation, aside from mild or moderate mitochondrial changes, the most relevant lesions included edema and vasoconstriction. Reperfusion was followed by the development of areas of necrosis forming contraction bands and an increment in the mitochondrial damage; the intercalated disks conserved their normal structure; edema became more prominent and was invariably accompanied by hemorrhage; vasoconstriction was very pronounced and was accompanied on occasion by evidence of capillary rupture; and inflammatory cells were observed in the interstitium. These results indicate that colloid must be added to Cape Town solution and that reperfusion probably requires selective approaches to deal with vasoconstriction and inflammation.

Animals↗
PubMed1998

Elecsys TSH, FT4, T4, T-uptake, FT3 and T3. Clinical results of a multicentre study.

6 assays for the assessment of thyroid function (TSH, FT4, T4, T-uptake, FT3 and T3) were targets of the International Multicenter Study on the random access analyzer Elecsys 2010. The aim of the study was to characterize the clinical performance of the assay in method comparison and reference range studies. The assays under evaluation were compared to a broad variety of radio isotopic and non-radio isotopic assays. They are suitable for serum and plasma samples. In case of TSH the study include 2nd and 3rd generation TSH procedures. In general, good to excellent correlations were found between the Elecsys and the respective routine methods. Systematic deviations were extraordinary low in case of TSH, FT4 and T4. Regarding the analysis of T3 and FT3 some systematic deviations in terms of standardization have been observed. Results of Elecsys T4 and Elecsys FT4 were independent of the serum total protein or serum albumin concentrations. In T3 and FT3 Elecsys the results of samples from NTI (non-thyroidal-illness) patients were decreased, reflecting the physiological situation in these patients. Studies using samples from healthy euthyroid as well as untreated hypo- and hyperthyroid individuals enabled us to assess the assays reference ranges.

Humans↗
PubMed1998

Elecsys CEA, PSA and AFP. Clinical results of a multicentre evaluation.

Three tumormarker assays, Elecsys CEA, PSA and AFP, have been evaluated in an international multicentre study to characterize their clinical performance and to verify the comparability with the corresponding tests of the Enzymun-Test product line and other methods. For each of the markers results were obtained from four laboratories. On the basis of 314 and 199 specimens respectively, (preliminary) reference ranges could be established for CEA and PSA. For the prostate marker, the age dependence of the antigen level could be clearly confirmed. Mean concentrations range between 0.51 ng/ml (< 40 years) and 3.57 ng/ml (> 70 years). Referring to CEA, 95th percentiles of 4.31 ng/ml and 2.69 ng/ml were elaborated for smokers and nonsmokers. In general, good to excellent correlations (r > 0.98) were found between the Elecsys and Enzymun-Tests. Regarding the systematic comparability of both systems, most of the slopes derived from the individual method comparison studies are within the +/- 10% range of the respective standardization results. The specific distribution pattern of the individual tumormarker values elaborated with sample material of known clinical background, reflects the well established categorization of different benign and malignant diseases according to their characteristic marker levels. Of utmost importance, however, is the excellent comparability of the Elecsys assays with the corresponding Enzymun-Tests and the FDA approved AIA 1200 tests from TOSOH in follow-up studies. Almost superimposable concentration curves guarantee that identical diagnostic information is derived from all three methods. Especially for PSA, a series of measurements on sera of prostatectomized patients proved the usability and clinical value of the test also for this particular indication. For either one of the Elecsys tests, the feasibility of using plasma as sample material was verified.

Adult↗
PubMed1997

Use of albumin in two Spanish university hospitals.

OBJECTIVES: The aim of this study was to characterize the use of seralbumin, evaluating how appropriate its prescription is and what possible economic repercussions may result from inappropriate use. METHODS: We performed a prospective study that included all patients receiving albumin in two University Hospitals from October 1995 to March 1996. The reasons for albumin use were considered appropriate if they coincided with the recommendations of a panel of experts. RESULTS: During the study period, 197 patients received albumin and a total of 3208 50-ml vials (20%) were used. The internal medicine and gastroenterology services prescribed this drug the most often. The most frequent prescription motives were paracentesis in cirrhotic patients (25.9%), hypoalbuminemia (24.9%) and chronic handling of cirrhotic patients (18.6%). Only 16 prescriptions (8.1%) (corresponding to 315 vials, 9.8%) were considered appropriate. One cause of inappropriate prescribing was that colloid solutions had not previously been used in 56 (30.9%) of the 186 inappropriate prescriptions. During the study period, 74,306 ECUs were spent on inappropriate indications. CONCLUSIONS: The use of albumin in our centers is incorrect and has important economic repercussions. Some educational and informative measures must be established to change this situation.

Albumins↗
PubMed1997

Structural and ultrastructural study of the myocardium after 24-hour preservation in University of Wisconsin solution.

This study deals with myocardial preservation after 24 hours of continuous perfusion with University of Wisconsin (UW) solution, focusing on the morphological changes produced by preservation and reperfusion, and their possible relationship to the composition of the solution and the immediate hemodynamic findings after orthotopic heart transplantation in dogs. Following preservation, the histological images of the myocardium were normal in almost every case. After revascularization, although 50% of the hearts recovered preoperative functional levels, there were relevant histological changes in all of them. These changes consisted of interstitial edema, damage to at least 50% of the mitochondria, presence of contraction bands, loss of intercellular junction structure and vasoconstriction. According to these results, the association of continuous perfusion and UW solution appears to be effective during the ischemic period of prolonged myocardial preservation, but not during reperfusion. Perhaps the proportion of viable hearts could be increased by preventing vasoconstriction.

Animals↗
PubMed1995

Electrophysiologic effects of procainamide, mexiletine, and amiodarone on the transplanted heart. Experimental study.

The effects of procainamide, mexiletine, and amiodarone on automaticity, conduction, and refractoriness were studied in a model of heterotopic heart transplantation in dogs that combined an innervated heart (recipient) and a denervated transplanted heart (donor). After the surgical procedure, 500 mg procainamide (n = 13), 200 mg plus 0.1 mg/kg per minute mexiletine (n = 10), or 150 mg amiodarone (n = 10) was administered intravenously. During a baseline period and after drug administration, each heart was assessed for atrioventricular interval; cycle length; sinoatrial conduction time; atrioventricular node anterograde and retrograde block points; atrioventricular node and ventricular antegrade effective refractory periods; PR, QRS, and QT intervals on electrocardiogram; systemic arterial, pulmonary arterial, central venous, and pulmonary capillary wedge pressures; and cardiac output. In recipients, procainamide reduced cardiac output, depressed sinus automaticity, slowed conduction time without affecting the QRS interval, and prolonged the nodal and ventricular refractoriness; in donor hearts, it depressed automaticity and prolonged nodal refractoriness, but did not modify conduction or ventricular refractoriness. Mexiletine only moderately depressed sinus automaticity in recipient hearts; it did not affect the other parameters either in recipient or transplanted hearts, nor did it alter the hemodynamic situation. Amiodarone produced hypotension, reduced cardiac output, and prolonged all the electrophysiologic intervals except the QRS interval in recipient hearts. These changes were even more pronounced in the transplanted hearts and led to extreme sinus bradycardia in four cases. Of these three drugs, mexiletine appears to be the safest should treatment for arrhythmias be necessary in transplant recipients.

Amiodarone↗
PubMed1990

Specific IgG and IgE responses to Dermatophagoides pteronyssinus in Sprague-Dawley rats.

Specific IgG and IgE antibodies against the mite Dermatophagoides pteronyssinus (Dp) have been determined in the serum of Sprague Dawley (SD) rats by enzyme linked immunosorbent assay (ELISA) and passive cutaneous anaphylaxis (PCA), respectively. Immunization of rats with Dp produces a rapid increase of serum specific IgE antibody levels which decrease when specific IgG antibodies start rising. The results indicate that the SD rat is a good model to induce a humoral immune response to allergen Dp.

Animals↗
PubMed1989

Hereditary nature of the pattern of the motor activity circadian rhythm in mice.

The inherited nature of the pattern of the daily motor activity function (MAF) has been studied using different families of the same strain of mice. The motor activity of 6 male mice, belonging to two different families (A and B was recorded during 54 days in LD conditions (12L:12D) using six inductive units. The register began the day just after weaning. A Fourier analysis was applied to motor activity data corresponding to observation periods of 24 hours. The daily power spectrum, with 20 harmonics, was calculated by obtaining the power content of each harmonic expressed as a percentage of the total power content of the MAF. A discriminant function based on the first fifteen harmonics was created to distinguish between the males of the two families. Then, the same discriminant function was applied to the daily power spectra of the progeny. It was also possible to differentiate among the mice (males and females) coming from fathers of family A and the mice coming from fathers of family B (p less than 0.02). This fact suggests that, in the power spectra of the progeny, there may be enough characteristic equal to that of their respective fathers and it further suggests that some characteristic of the MAF could have been inherited.

Animals↗
PubMed1988

Detection of changes in the mouse circadian rhythm induced by stress.

Mice were subjected to three types of acute stress (cold, forced swimming and tail hanging) in order to investigate the effects of stress on the motor activity circadian rhythm. This rhythm was studied using the cosinor method and spectral analysis. A statistically significant decrease in the amplitude and the power content of the circadian harmonic was found after stress application. These decreases could be due to a desynchronization of the circadian oscillators which drive the rhythm. The use of the power content of the circadian harmonic is proposed for the detection of the alterations due to stress.

Animals↗
PubMed1985

[Development of the circadian rhythm of motor activity in the mouse].

The evolutions of the total motor activity (TMA) and the power content of circadian harmonic (PCCH), through time, have been studied in six male mice, during 57 days from weaning. The best correlation between TMA and time is a hyperbolic function, reaching 75% of the asymptotic value when the animals are 24-25 days old. PCCH values have been adjusted to a hyperbola, reaching 75% of the asymptote when the animals are 30-34 days old.

Animals↗
PubMed1983

Comparative study of the gastrointestinal tolerability of tolmetin and 4'-acetamidophenyl-2-(5'-p-toluyl-1'-methylpyrrole) acetate (AU-8001).

The comparative gastrointestinal (GI) tolerability of 4'-acetamidophenyl-2-(5'-p-toluyl-1'-methylpyrrole) acetate (AU-8001), tolmetin and placebo have been studied in rat through a radioactive quantification method with Fe-59 of the GI microbleeding. The drugs were given orally at equimolecular doses of AU-8001 and sodium tolmetin equivalent to 100 mg/kg/day of tolmetin acid. Four days administration of sodium tolmetin induced significant increases of fecal radioactivity (p less than 0.005) whereas no difference was observed between animals treated with equimolecular doses of AU-8001 and control animals. The fecal elimination of radioactivity in the animals treated with sodium tolmetin was also significantly higher than in animals receiving AU-8001 (p less than 0.02).

Animals↗
PubMed1981

Urinary excretion of cyclic-AMP and cyclic-GMP in allergic children throughout seven months of hyposensitization treatment.

The authors studied urine excretion of cyclic-AMP and cyclic-GMP in normal and allergic children before and after hyposensitization to house dust. The cyclic-AMP excretion was found to b diminished in the asthmatic group before the treatment. The hyposensitization did not modify these low levels. No significant variation of cyclic-GMP excretion was found among the normal, ante or post-hyposensitization asthmatic groups.

Asthma↗