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Biomedical subjects

S Beltrán

Publications and source records attributed to S Beltrán.

8 recordsLinked to original sources
PubMed2006

Transplant renal artery stenosis: association with acute vascular rejection.

BACKGROUND: Transplant renal artery stenosis, the prevalence of which varies from 2% to 12%, is an important cause of hypertension and allograft dysfunction. We sought to determine the clinical characteristics of this disorder, assessing, predisposing factors, establishing treatment options, and examining patient outcomes. PATIENTS AND METHODS: Among 321 renal allograft recipients between November 1996 and December 2004, six patients were identified with this finding. We analyzed their clinical data before and after treatment compared with the 315 recipients face of the disorder. RESULTS: The six patients with the disorder were diagnosed within the first year (2 to 8 months; median 5.5 months). All patients displayed renal dysfunction, peripheral edema, and new-onset or uncontrolled hypertension at presentation. Abnormal Doppler findings were observed in 5 (83.3%) patients. The hemodynamically significant stenosis was successfully treated with percutaneous transluminal angioplasty (PTA) in all six. However, 3 (50%) patients displayed recurrent stenosis requiring a second PTA. The mean serum creatinine level decreased from a pre-PTA value of 4.4 +/- 1.8 mg/dL to a 1-month post-PTA value of 2.2 +/- 0.5 mg/dL (P = .027). Patients had no significant improvement in mean systolic and diastolic pressure. Vascular acute rejection episodes were more frequent among the affected than the control group (3/6; 50% vs 18/315; 5.7%; P < .001). No differences were found in age, sex, donor type, etiology of renal disease, immunosuppression, acute tubular necrosis, acute cellular rejection, cold ischemia time, or HLA matching. CONCLUSION: Transplant renal artery stenosis is a common cause of hypertension and renal allograft dysfunction. Acute vascular rejection is associated with this disorder.

Angioplasty, Balloon, Coronary↗
PubMed2006

Erythropoietin treatment in the sixth posttransplant month as a prognostic factor for renal allograft survival.

The purpose of this work was to assess the prognostic value of the need for erythropoietin (EPO) treatment at 6 months after transplantation. We retrospectively reviewed the outcomes of 143 consecutive cadaveric kidney transplants performed between January 2000 and April 2004, functioning at 6 months postransplantation. Patients were divided into two groups: group EPO6m (n = 24) received EPO treatment in the sixth month, and a control group (n = 119) did not receive EPO. Renal function deterioration (RFD) was considered to be a sustained decrease in creatinine clearance (CrCl) greater than 20% between the sixth month postransplant and the last visit. Mean follow-up was 38 +/- 16 months. The mean ages of the donor (57 +/- 9 vs 49 +/- 12 years; P = .001) and the recipient (59 +/- 12 vs 47 +/- 17 years; P = .000) were greater in the EPO6m group. Delayed graft function (83% vs 48%; P = .001) was more frequent in the EPO6m group. At 6 months after transplantation the EPO6m group showed lower hemoglobin (11.52 +/- 1.71 vs 13.32 +/- 1.69 g/dL; P = .000), higher serum creatinine (2.31 +/- 0.72 vs 1.65 +/- 0.53 mg/dL; P = .000), lower CrCl (33.53 +/- 10.83 vs 53.6 +/- 17.58 mL/min; P = .000), and similar proteinuria. RFD was more common in the EPO6m group (38% vs 10%; P = .026), with a different pattern of evolution of CrCl (-0.098 +/- 0.176 vs +0.093 +/- 0.396 mL/min/mo, P = .000). Multivariate analysis demonstrated that treatment with EPO at 6 months was the only predictor of RFD (RR 4.46; 1.58 to 12.58; P = .005). The need for EPO at 6 months postransplant was a good predictor of later renal allograft deterioration, more sensitive than serum creatinine or proteinuria.

Aged↗
PubMed2000

Extraction of natural complex phenols and tannins from grape seeds by using supercritical mixtures of carbon dioxide and alcohol.

Proanthocyanidins are supposed to have some therapeutical properties as antioxidants and antineoplasics. Most of the proanthocyanidins, however, are not commercialized since their separation from natural sources is either very expensive or not well-known. In this work, the feasibility of application of mixtures of carbon dioxide and alcohol under supercritical conditions for selective extraction of some phenolic compounds from grape seeds has been studied, among them some low polymerized proanthocyanidins, their main monomer units, (+)-catechin and (-)-epicatechin, and some low molecular weight phenolic compounds, like gallic acid. An analytical-scale supercritical fluid extractor, whose operation was previously optimized, was used to carry out the experiments. A commercial concentrate of complex phenols and tannins from grape seeds was subjected to supercritical extraction in order to find the best operation conditions before directly extracting defatted milled grape seeds. The solvent capacity was found to increase with pressure and with the amount of alcohol used as cosolvent as expected. Such variation in solvent capacity could be used for design of a selective separation process where individual phenolic compounds or groups of them could be obtained. HPLC coupled with two types of detectors, diode array and mass spectrometry, was used for tentative identification and quantification of complex phenols and tannins in the extracts and in the raw materials used for extraction.

Alcohols↗
PubMed1999

Various applications of liquid chromatography-mass spectrometry to the analysis of phenolic compounds.

Different options of liquid chromatography-mass spectrometry were used to establish the most suitable ion source and conditions to analyse or detect some low-molecular mass phenols, flavan-3-ols, and apply such conditions to a complex sample (wine). Data presented in this work confirm the great utility of atmospheric pressure-ionisation electrospray mass spectrometry coupled to HPLC for analysis of phenolic compounds, under negative mode in the case of low-molecular mass phenols, and under both positive and negative modes in flavan-3-ol compounds. A fragmentor voltage of 60 V could be the most suitable for analysing the compounds under study.

Chromatography, High Pressure Liquid↗
PubMed1978

[Chronic gastritis in children (author's transl)].

The gastric mucosa in 113 children from 6 months to 14 years old was studied from a histopathological point of view. Samples were obtained by means of a multiple biopsy technique during an endoscopic examination. The patients were divided into two groups. Group A was composed of 97 children with abdominal pain of an unknown etiology. Group B was formed of 16 patients with extragastric pathology in whom it was possible to take biopsies during an endoscopic exam. All of the biopsies were normal, and therefore were used as the control group. 49 patients from group A were histologically normal. In the other 48, lesions of chronic gastritis ranging in severity, were found in the antrum and/or in the gastric body. An analysis of the histopathological findings, and of the lesional sings of activity was done in accordance with Whitehead's criteria. Macroscopic objective features observed during the endoscopical examinations, were also evaluated and compared with the existence or nonexistence of chronic gastritis lesions. In the gastric body, the existence of endoscopic features such as enlarged folds, erosions or friable mucosa, were found to be coincident with the presence of histologic lesions of chronic gastritis. The same relationship was found in the antrum between the granular mucosa and/or irregular coloration and the lesions of chronic gastritis. In the same time, acid secretion studies (BAO, MAO and PAO) from 40 patients from group A were done using pentagastrin as a stimulant. It was demonstrated that both basal acid output and maximal acid were significantly lowered in cases of advanced lesions of chronic gastritis located in the gastric body. Finally the importance of this entity is emphasized in the gastrointestinal pathology in children.

Adolescent↗