Search PubMed⌕ Search

Biomedical subjects

A Alvarez

Publications and source records attributed to A Alvarez.

At least 289 records · Page 16Linked to original sources
PubMedDate not supplied

Postextrasystolic potentiation of systolic gradient in valvular aortic stenosis: clinical usefulness and analysis of hemodynamic factors.

To analyze the behavior of aortic valve gradient (AVG) after ventricular extrasystole (VE), we studied 36 pure valvular aortic stenoses (AS) free of coronary artery disease and obstructive hypertrophic cardiomyopathy, in whom basal (B) (74 +/- 32 mm Hg) and catheter-induced post-VE (110 +/- 50 mm Hg) AVG were obtained. In all 26 cases with valve area less than 0.70 cm2, the post-VE AVG was greater than or equal to 70 mm Hg. In 19 cases AVG after two or more consecutive VE were also obtained. Maximal post-VE AVG was obtained after multiple VE (19 cases) and/or after one VE causing a post-VE pause equal or longer than 1.7 basal cardiac cycles (post-VE RR greater than or equal to 1.7 B RR) (9 cases). Basal and postsingle VE AVG, up to a post-VE RR greater than or equal to 1.7 B RR, were a linear function of previous RR (r greater than or equal to 0.90), regression line slope increasing with AS severity (P = .05). Inotropic state measured by PEP/LVET only increased after multiple VE, P less than .01. AVG after multiple VE was independent of post-VE RR. Thus, 1) post-VE potentiation of AVG may be seen with fixed valvular AS without obstructive cardiomyopathy; 2) post-VE AVG is a function of compensatory pause after single VE and of increased inotropism after multiple VE; 3) analysis of maximal post-VE AVG generated as described is reliable and useful for assessing AS severity (post-VE AVG greater than or equal to 70 mm Hg meaning an aortic valve area less than 0.70 cm2) and may supplement valve area calculations.

Aortic Valve↗
PubMedDate not supplied

Two different subpopulations of Ig-bearing cells in lymphoid organs of rainbow trout.

In a previous report we described the existence of two structural and antigenic variants of light chains in serum trout Igs, defined by mAbs 2H9 and 2A1. In this report, we analyse the cell distribution, the "in vitro" kinetics of production, and the ontogenic appearance of these two variants. Both variants were already present at day 8 before hatching and their kinetics of appearance correlated with that of total Ig, showing a peak around hatching. These mAbs stained two distinct lymphoid cell populations in the pronephros, mesonephros, spleen, and peripheral blood. Both mAbs reacted with approximately 1% of thymocytes. The ratio between these two cell populations (2A1+/2H9+) was about 2/1 in the lymphoid organs analysed. No differences were found between the profiles of the "in vitro" production of these variants in pronephric cell cultures stimulated with LPS. In these cultures, the 2A1 and 2H9 Igs together accounted for 10-70% of the total trout Ig produced, suggesting the existence of at least one additional L chain variant.

Animals↗
PubMedDate not supplied

Rapid determination of alpha emitters using Actinide resin.

The European Commission has recently published the recommended radiological protection criteria for the clearance of building and building rubble from the dismantling of nuclear installations. Radionuclide specific clearance levels for actinides are very low (between 0.1 and 1 Bq g(-1)). The prevalence of natural radionuclides in rubble materials makes the verification of these levels by direct alpha counting impossible. The capability of Actinide resin (Eichrom Industries, Inc.) for extracting plutonium and americium from rubble samples has been tested in this work. Besides a strong affinity for actinides in the tri, tetra and hexavalent oxidation states, this extraction chromatographic resin presents an easy recovery of absorbed radionuclides. The retention capability was evaluated on rubble samples spiked with certified radionuclide standards (239Pu and 241Am). Samples were leached with nitric acid, passed through a chromatographic column containing the resin and the elution fraction was measured by LSC. Actinide retention varies from 60% to 80%. Based on these results, a rapid method for the verification of clearance levels for actinides in rubble samples is proposed.

Journal Article↗
PubMedDate not supplied

Method for actinides and Sr-90 determination in urine samples.

The primary goal of radiation protection in decommissioning and decontamination of the old nuclear facilities of the CIEMAT is to monitor and minimize exposure of personnel. Monitoring programs include determination of actinides and 90Sr in biological samples. A technique for the sequential measurement of low levels of 239Pu, 241Am and 90Sr in urine samples has been developed. The method involves coprecipitation of these radionuclides as phosphates from bulk urine sample. Separation of Plutonium is carried out using a conventional anion exchange technique. Americium and strontium isolations are achieved sequentially by chromatographic extraction (Tru.Spec and Sr.Spec columns) from the load and rinse solutions coming from the anion exchange column. Plutonium and Americium measurements are performed by alpha spectrometry. The mean recovery obtained is 80% and the detection limit for 24 h urine sample (1.41) is 0.6 mBq L-1. 90Sr determination is made by liquid scintillation counting. The detection limit in this case is 1.1 E-01 Bq/L.

Actinoid Series Elements↗
PubMedDate not supplied

Helical CT in renal transplantation: normal findings and early and late complications.

Over a 5-year period, 346 helical computed tomographic (CT) studies were performed in renal transplant recipients. Helical CT proved useful in this context by depicting parenchymal, perirenal, renal sinus, pyeloureteral, and vascular complications in great detail. CT often delineates fluid collections and their anatomic relationship to adjacent structures better than ultrasonography (US), particularly in obese patients. CT-guided puncture and drainage can be performed in cases in which US is deemed inadequate. CT angiography can depict arterial diseases such as stenosis, thrombosis, arteriovenous fistulas, aneurysms, and pseudoaneurysms in the graft artery and in the recipient iliac arterial system, thereby obviating conventional angiography in some cases. Helical CT with three-dimensional image reformatting allows accurate imaging of the entire course of ureteral and periureteral diseases (eg, hydronephrosis, ureteral leak and stricture, pyeloureteral obstruction). CT can be used in the confirmation and staging of malignancies of the renal parenchyma and urothelium. It is also helpful in evaluating associated disease in the native kidneys, acute and chronic rejection, graft embolization, and end-stage disease. Although US and nuclear medicine examination are the imaging modalities of choice in renal transplantation, helical CT is a valuable alternative when these techniques are inconclusive.

Abscess↗
PubMedDate not supplied

Functional recovery and social outcome after cerebral infarction in young adults.

This study was designed to assess the return to work, the poststroke depression and the quality of life after a cerebral infarction in young adults and was conducted on 71 consecutive young patients (aged 15-45 years) affected by a cerebral infarct who were hospitalized for the first time and discharged at least 1 year before the study. Data about risk factors, etiology, side and territory of stroke, social characteristics of the patient (age, sex, profession, educational level, family situation), poststroke seizures, recurrent stroke, other vascular events, and deaths were collected. Neurological deficits were graded with the National Institutes of Health (NIH) Stroke Scale. Poststroke depression (PSD) was quantified using the DSM-IIIR criteria and the Montgomery Asberg Depression Rating Scale. Outcomes were rated with the Ranking Scale, the Barthel Index and the Glasgow Outcome Scale. Quality of life was assessed with the Sickness Impact Profile. Follow-up information was obtained by interview and neurological examination. Follow-up information was obtained in 65 patients at a mean of 31.7 +/- 13.0 (range 12-59) months, as 2 patients died and 4 were lost to follow-up and were thus excluded from this study. Poststroke seizures occurred in 7 patients (10.8%) and recurrent strokes in 4 patients (6.2%), but none were fatal. The outcome after stroke among survivors was usually good, since more than two-thirds of the patients (69.8%) reported no problem, 11.1% moderate handicap and one-fifth major handicap. Forty-six patients (73%) returned to work: the time period ranging from several days after stroke to 40 months, with a mean of 8 months. However, adjustments in their occupation were necessary for 12 patients (26.1%). PSD was common, since 48.31% of the patients were classified as depressed. PSD was associated with the localization of the infarct (carotid territory), a severe disability, a bad general outcome, and an absence of return to work. Their opinion about their quality of life was negative among approximately 30% of the patients, especially in emotional and alertness behaviors. social interaction, recreation and pastimes. The general outcome after cerebral infarct in young adults is usually good. However, the risk of a PSD is high, and only half of the patients had returned to their previous work. A remaining psychosocial handicap and depression of sexual activity impaired the quality of life. In multivariate analysis, a low NIH score at admission is a significant predictor for return to work, the absence of PSD, and a good quality of life.

Adolescent↗
PubMedDate not supplied

Cyclosporin A upmodulates the alpha-subunit of the interleukin-2 receptor and the metastatic ability of murine B16F10 melanoma cells.

In the present study, the effect of in vitro cyclosporin A (CsA) treatment on IL-2R expression and the metastatic behavior of B16F10 melanoma cells has been reported. CsA treatment was found to increase the percentage of B16F10 cells expressing the alpha-subunit of IL-2R on the cell surface and also at the mRNA level. Moreover, CsA treated B16F10 cells also express the beta-subunit of IL-2. In vivo experiments showed that CsA increases the affinity of B16F10 metastazing cells for the liver and decreases that for the lung. CsA modulated the expression of MHC class I and class II antigens, but no significant differences in the resistance of CsA-treated B16F10 cells to NK lysis were observed. Finally, proliferation of B16F10 cells in the presence of several doses of CsA did not vary and CsA increased the amount of IL-1beta mRNA expression. These results suggest that CsA, through the modulation of cytokines and MHC antigen expression on B16F10 cells, could have an effect upon the metastatic progression of the B16F10 melanoma.

Animals↗
PubMedDate not supplied

Membranous levels of c-erbB-2 oncoprotein in gastric cancer: their relationship with clinicopathological parameters and their prognostic significance.

BACKGROUND: The protein encoded by the c-erbB-2 gene is a membrane receptor expressed in a variety of solid human cancers and directly related to poor prognosis. The objective of this work was to evaluate the clinical value of the quantification of membranous oncoprotein levels in gastric cancer. MATERIALS AND METHODS: Membranous c-erbB-2 levels were examined by means of a sandwich immunoenzymatic assay in 82 patients with gastric cancer. The median follow-up period for these patients was 16 months. In addition, c-erbB-2 expression was analyzed by immunohistochemistry in 57 gastric carcinomas. RESULTS: Membranous c-erbB-2 levels ranged widely in the studied tumors (44-112,000 NHU/mg protein). Median c-erbB2 content was significantly higher in intestinal-type tumors than in diffuse-type tumors (p = 0.01). In addition, high levels of c-erbB-2 were significantly associated with shorter relapse-free survival and overall survival in patients with resectable gastric carcinomas (p = 0.01 and p = 0.04, respectively). However, the correlation between immunohistochemistry and ELISA determinations did not reach statistical significance. CONCLUSION: Our results suggest a potential prognostic value of membranous c-erbB-2 quantification by immunoenzymatic assay in gastric cancer. However, its possible role in the selection of patients with a view to the possible introduction of Herceptin as a novel drug against gastric cancer is at present uncertain.

Aged↗
PubMedDate not supplied

Clinical significance of cathepsin D concentration in tumor cytosol of primary breast cancer.

BACKGROUND: Cathepsin D is the proteolytic enzyme most frequently implicated as a prognostic factor in primary breast cancer. In the present study we evaluated by means of an immunoradiometric assay the tumor content of this protease in primary breast cancer, its relationship with tumor-related clinical and pathological parameters, and its prognostic significance in a large series of breast cancer patients. METHOD: The study comprised 1033 women with histologically established invasive breast cancer. Cathepsin D was measured in cytosol samples by means of an immunoradiometric assay to determine the total amount of cathepsin D (52 kDa, 48 kDa and 34 kDa). Evaluation of relapse-free survival and cause-specific survival was performed in the group of 1003 patients without evidence of metastasis at the time of initial diagnosis. The median follow-up of the patients who were free of recurrence was 54 months. RESULTS: Cathepsin D levels showed a wide range among the studied tumors (n = 1033; median (range) 41 (0.9-2504) pmol/mg protein). Statistical analysis showed that the median cathepsin D levels were considerably higher in large tumors (T2-4) than in smaller ones (T1) (p = 0.017), as well as in node-positive than in node-negative tumors (p = 0.004). Cathepsin D levels were also higher in ductal tumors than in the other histological types (p = 0.001), as well as in moderately or poorly differentiated tumors (p < 0.001). Likewise, the median value of the protease was significantly higher in ER or PgR-positive tumors than in hormone receptor-negative ones (p = 0.011 and p = 0.004, respectively), as well as in aneuploid tumors than in diploid tumors (p = 0.029). Multivariate analysis demonstrated that elevated cathepsin D levels (> 59 pmol/mg protein) were notably associated with a shorter cause-specific survival in the whole group of patients with breast cancer, as well as in the subgroup of node-positive patients (p < 0.05). CONCLUSIONS: This study suggests that elevated intratumoral cathepsin D levels may identify a subset of node-positive breast cancer patients showing a high probability of earlier death.

Adult↗