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Biomedical subjects

A Ríos

Publications and source records attributed to A Ríos.

At least 55 records · Page 3Linked to original sources
PubMed2005

[Multivariate study of the psychosocial factors affecting public attitude towards organ donation].

INTRODUCTION: Organ transplantation is a therapy which depends on society for its development. The objectives here are: 1) to understand the structure of public opinion towards organ donation in the population aged over 15 years of age in our Community; 2) to analyse the psychosocial variables which affect this opinion and 3) to define the population profiles on this matter. MATERIALS AND METHODS: Random sample (n = 2.000) stratified for age, sex and geographical location (error for 95.5%, e +/- 2.24) to whom we apply a questionnaire about the psychosocial aspects of organ donation. Descriptive statistics, Student's t-test, Chi-squared test and logistical regression analysis. RESULTS: 63% have a favourable attitude towards organ donation, of which 11% have a donor's card. A statistical association has been observed between favourable public opinion and different psychosocial variables (p < 0.05), with some independent variables persisting in the multivariate analysis such as age, level of education (OR = 1.78), information given by family members (OR = 1.62), health workers (OR = 2.01) and talks in educational centres (OR = 2.13); previous experience with donation and transplantation (OR = 2.02), knowledge of the concept of brain death (OR = 1.4); partner's favourable opinion towards donation (OR = 2.6), being a blood donor (OR = 3), taking part in prosocial activities (OR = 1.6) and attitude towards incineration of the cadaver after death (OR = 1.8). CONCLUSIONS: The profile of a person who is against donation is of a man or woman, > 50 years of age, with primary studies or below, with no previous experience of the matter, who does not understand the concept of brain death nor their partner's opinion towards donation, who has not found out any information about donation through specialised forums, with an unfavourable opinion towards blood donation or pro-social activities and who is fearful of manipulation of the cadaver after death.

Adolescent↗
PubMed2004

Monitoring of bacterial contamination in food samples using capillary zone electrophoresis.

A capillary electrophoresis method with UV detection is proposed for the identification and quantitation of bacterial contamination in food samples. The electrophoretic separation relies on the differential mobility of bacteria in the capillary. Electrophoretic resolution is improved by using calcium and myoinositol hexakisphosphate as specific ions that interact with the bacterial surface changing its electrical properties and electrophoretic mobility. The proposed method allows the effective separation of eight different types of bacteria in only 25 min. It was successfully used to detect the presence of bacteria in contaminated food. The precision of the analysis of real spiked samples ranges from 3.3 to 7.0%, and the overall analysis time is 7 h, which is much shorter than the 24-48 h typically required for plate counts. The validity of the method was established by comparison with the standard plate counting method.

Animals↗
PubMed2004

Bioguided extraction of polyphenols from grape marc by using an alternative supercritical-fluid extraction method based on a liquid solvent trap.

The biological activity of polyphenols extracted from grape marc was studied with a view to finding a new use for this winery waste. Polyphenols were extracted by using an alternative supercritical-fluid extraction method based on the use of a liquid trap that allows extracted polyphenols to be retained in a saline buffer, thus avoiding the need for the organic solvent required to elute polyphenols from a solid trap. The major extraction variables influencing the performance of the liquid trap (viz. CO(2) modifier content, flow-rate, extraction time and trap volume) were optimized. The proposed method was applied to the supercritical-fluid extraction extraction of 0.3 g grape marc with CO(2) modified with 3% methanol at 350 bar at 50 degrees C (CO(2) density 0.9 g mL(-1)) for 20 min, using a liquid flow-rate of 0.9 mL min(-1). The polyphenol extracts thus obtained exhibited cytotoxic effects that induced apoptosis in tumour cells.

Apoptosis↗
PubMed2004

Risk factors for malignancy in multinodular goitres.

BACKGROUND: Multinodular goitre (MNG) is quite often associated with thyroid carcinoma, but the risk factors for malignancy are not well known. The aim is to analyse patients with thyroid carcinoma associated with MNG to determine the clinical risk factors for malignancy. METHOD: From a series of 672 MNGs we analysed a subgroup of 59 patients presenting with an associated thyroid carcinoma. The variables analysed were age, sex, family history, cervical radiation therapy, residence in areas of endemic goitre, prior thyroid surgery, time of evolution, asymptomatic status, hyperthyroidism, compressive syndromes, intrathoracic prolongation, goitre consistency and cervical adenopathies. These were compared to MNGs not developing malignancy using the Chi-squared test, Student's t test and a logistic regression test. RESULTS: Of the 59 cases, 37 corresponded to a microcarcinoma (< or =1 cm). The most common histological type was papillary (n=48), followed by follicular (n=6). In 20 cases the carcinoma was multifocal, and capsular involvement was noted in 16 patients, lymph node involvement in five and vascular involvement in another five. The multivariate analysis confirmed the following as independent variables associated with the presence of carcinoma: family history of thyroid pathology (RR=1.6), history of cervical radiation therapy (RR=1.8), recurrent goitre (RR=2.1) and presence of adenopathies on physical exploration (RR=1.6). CONCLUSION: The risk factors for carcinoma associated with MNG are family history of thyroid pathology, personal history of cervical radiation therapy, prior surgery and presence of cervical adenopathies.

Adenocarcinoma, Follicular↗
PubMed2004

Expression of HLA-G in inflammatory bowel disease provides a potential way to distinguish between ulcerative colitis and Crohn's disease.

In addition to being involved in nutrient uptake, the epithelial mucosa constitute the first line of defense against microbial pathogens. A direct consequence of this physiological function is a very complex network of immunological interactions that lead to a strong control of the mucosal immune balance. The dysfunction of immunological tolerance is likely to be a cause of inflammatory bowel disease (IBD), ulcerative colitis (UC) and Crohn's disease (CD). HLA-G is a non-classical major histocompatibility complex (HLA) class I molecule, which is highly expressed by human cytotrophoblast cells. These cells play a role in immune tolerance by protecting trophoblasts from being killed by uterine NK cells. Because of the deregulation of immune system activity in IBD, as well as the immunoregulatory role of HLA-G, we have analyzed the expression of HLA-G in intestinal biopsies of patients with UC and CD. Our study shows that the differential expression of HLA-G provides a potential way to distinguish between UC and CD. Although the reason for this differential expression is unclear, it might involve a different mechanism of immune regulation. In addition, we demonstrate that in the lamina propria of the colon of patients with UC, IL-10 is strongly expressed. In conclusion, the presence of HLA-G on the surface of intestinal epithelial cell in patients with UC lends support to the notion that this molecule may serve as a regulator of mucosal immune responses to antigens of undefined origin. Thus, this different pattern of HLA-G expression may help to differentiate between the immunopathogenesis of CD and UC.

Biopsy↗
PubMed2003

Psychosocial profile in favor of organ donation.

INTRODUCTION: The lack of organ donation continues to be a major limiting factor in transplantation. Our aims are: (1) to define the psychosocial profile against organ donation, and (2) to determine the impact of a law on the procurement and transplantation of organs based on "presumed consent" in the population. MATERIALS AND METHODS: The population in this study (n = 2000) was randomly selected and stratified according to sex, age, and geographic localization. The attitude toward organ donation and transplantation was evaluated according to a questionnaire that probed psychosocial aspects of donation. Statistical comparisons were performed using the chi2 and logistic regression tests. RESULTS: The population attitude toward organ donation was favorable in 63% of subjects, unfavorable in 31%, and 6% did not respond. With regard to the law based on "presumed consent," only 24% of the population agreed with the law; 53% thought it was an abuse of authority. The population subgroup with a negative attitude to the law was characterized by: age over 40 years, low educational level, no previous experience with organ donation or transplant, no experience in prosocial activities, a refusal to accept cadaver manipulation or mutilation, and lack of knowledge of the brain-death concept. CONCLUSIONS: The psychosocial profile against donation is a person above 40 years with a low level of education who has never performed prosocial activities, did not have previous experience with organ donation or transplantation, displays no knowledge of the brain-death concept, and rejects cadaver manipulation. For these people a law based on "presumed consent" is considered an abuse of authority.

Adolescent↗
PubMed2003

Description of a new auxiliary heterotopic partial liver transplantation technique with portal vein arteriolization of applicability in heterotopic liver xenotransplantation.

OBJECTIVE: The aim of this study was to describe a new model of auxiliary heterotopic partial liver transplantation with portal vein arterialization. MATERIALS AND METHODS: Three standard hepatectomies were performed in pigs. The left lateral lobe was surgically resected and portal vein arteriolization constructed by an end-to-side "Y" anastomoses between the distal to the celiac axis aorta and the portal vein. RESULTS: The graft was placed in the left iliaca fossa using anastomoses of the donor infrahepatic inferior cava vein end-to-side to the host infrarenal inferior vein and the donor aortic stump with portal vein arteriolization end-to-side to the left iliac artery. After graft reperfusion, the 3 recipients showed intraoperative hypotension, which was treated with fluid administration and vasoactive drugs. At the end of the operation, the graft displayed normal arterial blood flow and good venous drainage. The donor liver graft appeared more red than the host liver, which was due to the increased arterial blood flow. One pig of 3 died at 24 hours after surgery, probably due to hypothermia. However, the other 2 pigs survived the procedure and remained stable. Echographic monitoring showed intrahepatic arterial expansion, which may be the result of high blood pressure due to the arteriolization procedure. CONCLUSIONS: We have developed a novel and easy to perform technique that diminishes the number of anastomoses and does not involve vessels from other organs.

Anastomosis, Surgical↗
PubMed2002

Screening of aflatoxins in feed samples using a flow system coupled to capillary electrophoresis.

A method is proposed which presents a new approach to the joint use of capillary electrophoresis (CE) commercial equipment and a flow system. This flow system allows the total determination of several compounds by using a fluorimetric screening system. The individual determination for each analyte is performed by the CE proposed method. The screening procedure uses simple equipment and operations and provides a yes/no binary response that occasionally requires confirmation. A fast, simple, and reliable method has been developed in order to determine the most frequent mycotoxins in feed samples using micellar electrokinetic capillary chromatography (MECC). An extraction step followed by a purification step was carried out on the samples in order to remove interference substances before analysis. A C18 column was chosen to concentrate the mycotoxins, and the analytes were eluted from C18 using methanol. The MECC method allows the separation of six mycotoxins within 50 min with a reproducibility as RSD between 7.45 and 13.06%, and a limit of detection (LOD) between 0.02 and 0.06 mg l(-1) for all the mycotoxins. These LODs were clearly below legal limits (0.05 mg l(-1)).

Aflatoxins↗
PubMed2002

Determination of monoterpene hydrocarbons and alcohols in Majorana hortensis Moench by micellar electrokinetic capillary chromatographic.

Micellar electrokinetic capillary chromatography was used to determine the essential oils obtained by steam distillation of different samples of marjoram (Majorana hortensis Moench) dried leaves and flowers. The electrophoretic method consisted of a running buffer of 10 mM NaH2PO4, 6 mM Na2B4O7, 50 mM SDS, 7 mM gamma-cyclodextrin, and 10% acetonitrile, adjusted to pH 8.0 by the addition of 0.1 M H3PO4. The following monoterpene hydrocarbons and alcohol compounds were extracted from real samples and determined by the method proposed: alpha-pinene, gamma-terpinene, alpha-terpinene, terpinolene, p-cymene, linalool, alpha-terpineol, and terpinen-4-ol. The most prominent component of dried leaves, flowers, and commercial samples was terpinen-4-ol in four of the samples analyzed; only in one sample was alpha-terpineol present as the major compound.

Alcohols↗
PubMed2002

Prognostic factors in thymic epithelial neoplasms.

OBJECTIVES: The primary thymic epithelial neoplasms (PTENs) are uncommon tumours with a broad spectrum of both biological and morphological features. The aim of this study is to analyse the prognostic factors that influence survival. METHODS: Forty-four patients with a complete follow-up were analysed. Nine patients (20.5%) were asymptomatic, the most common symptoms in the rest being myasthenia gravis and dyspnoea. All the patients underwent surgery, 30 cases (68.2%) receiving total thymectomy and the rest a partial resection or biopsy. Marino-Müller's histological classification showed the mixed type to be the most common (52.3%). Clinical staging was done according to the Masaoka classification, which gave the most common stage as stage III (34.1%). RESULTS: Twelve patients died during a mean follow-up of 8.2 +/- 3.5 years. The accumulated survival rate was 77% at 5 years and 60% at 10 years. Analysis of the survival curves shows significant differences (P<0.05) when considering surgical technique, clinical staging and histological subtype. The multivariate analysis shows the only parameters with prognostic significance in PTENs to be clinical staging and histological type (P<0.001). CONCLUSIONS: The most important prognostic factors in PTENs are Masaoka's clinical staging and Marino-Müller's histological subtype.

Adolescent↗
PubMed2001

Coupling continuous separation techniques to capillary electrophoresis.

One of the weak points of capillary electrophoresis is the need to implement rigorously sample pretreatment because its great impact on the quality of the qualitative and quantitative results provided. One of the approaches to solve this problem is through the symbiosis of automatic continuous flow systems (CFSs) and capillary electrophoresis (CE). In this review a systematic approach to CFS-CE coupling is presented and discussed. The design of the corresponding interface depends on three factors, namely: (a) the characteristics of the CFS involved which can be non-chromatographic and chromatographic; (b) the type of CE equipment: laboratory-made or commercially available; and (c) the type of connection which can be in-line (on-capillary), on-line or mixed off/on-line. These are the basic criteria to qualify the hyphenation of CFS (solid-phase extraction, dialysis, gas diffusion, evaporation, direct leaching) with CE described so far and applied to determine a variety of analytes in many different types of samples. A critical discussion allows one to demonstrate that this symbiosis is an important topic in research and development, besides separation and detection, to consolidate CE as a routine analytical tool.

Chromatography, High Pressure Liquid↗
PubMed2001

Use of eosin as a fluorophore in capillary electrophoresis with laser detection.

Eosin has been used to generate the background signal for indirect fluorimetric detection of inorganic and organic ions, simultaneously separated by capillary zone electrophoresis (CZE). This reagent provides constant fluorescence over the pH range of 5-10 and is compatible with the excitation by an argon ion laser at 488 nm with emission at 520 nm. The use of esosine as fluorophore, H3BO3, and Na2B4O7 as electrolyte and diethylentriamine as modifier of the electroosmotic flow in CZE were optimised. The analytical potential of the studied buffer was tested on a group of 12 anions, used as model compounds. Both, hydrodynamic and electrokinetic injection mode were optimised. The detection limits determined by the last injection mode, were in the range 0.008-0.037 mg l(-1). By using this method, the quantitation of the common anions in tap and mineral water has been carried out successfully.

Electrophoresis, Capillary↗