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Biomedical subjects

A Parera

Publications and source records attributed to A Parera.

14 recordsLinked to original sources
PubMed2006

Description of controlled trials published in Methods and Findings, 1979-2002.

It is thought that the controlled trial (CT) is the most adequate research method to assess a therapeutic intervention in terms of efficacy, and it also constitutes the basis for the development of systematic reviews on health interventions. To identify and obtain the majority of published CTs is not an easy task, mainly because of limitations concerning the currently available electronic sources. The aim of the present work was to identify, describe, and assess the quality of CTs published in the journal Methods and Findings in Experimental and Clinical Pharmacology (M&F). Additionally, to assess the retrievability of both methods, a search was performed in Medline (PubMed access) through the use of an optimal search strategy for CTs. A total of 189 original studies out of a total of 2796 reviewed articles met the CT criteria according to the Jadad scale score, we could hold that only 58% of the CTs were of good quality. The present work confirms, once again, the limitations of a CT search performed exclusively through Medline (sensitivity 64% and specificity 98%). In conclusion, we suggest that the journal M&F explicitly joins the International CONSORT Statement.

Clinical Trials, Phase III as Topic↗
PubMed2004

Safety and efficacy of argon plasma coagulator ablation therapy for flat colorectal adenomas.

INTRODUCTION: argon-plasma coagulation (APC) has been used safely and efficaciously in multiple settings including colon polyp treatment. The aim of this study was to evaluate APC efficacy and safety in the treatment of flat colorectal adenomas. MATERIALS AND METHODS: APC ablation was prospectively performed and evaluated in 22 consecutive patients with colorectal adenomas, 11 of which had large sessile adenomas that were treated with piecemeal polypectomy and APC ablation of residual adenomatous tissue, whereas the remaining eleven patients with flat or carpet-like adenomas were only treated with APC. The mean initial longitudinal extension of adenomas to be treated with APC was 22 mm (range, 20 to 40 mm). RESULTS: the mean age of patients was 70 years. Adenomas were found most frequently in the rectum (50%) and cecum (23%). Complete ablation was achieved in 90.9% of adenomas. Recurrence was observed in 20% of patients, all of them in the rectum, after a mean follow-up period of 16.3 months (range, 8 to 35). All recurrences were managed satisfactorily. No major complications were seen. CONCLUSIONS: argon plasma coagulator ablation of flat colorectal adenomas is an efficacious and safe technique, specially in the right colon, but results must be confirmed in controlled trials with a higher number of patients.

Adenoma↗
PubMed2000

Adsorption of omeprazole on latex particles and characterization of the complex.

Omeprazole is an antisecretory drug used against gastric ulcers. It quickly decomposes in an acid medium, however, therefore making it a matter of great interest to protect it in these conditions and determine the ideal adsorption conditions for this drug on latex particles for formulation designs--oral suspensions--containing polymers with the aim of delivering different drugs in a sustained and controlled action. Time, pH, and concentration of the active ingredient for which maximum adsorption occurs, were determined. The findings suggest that adsorption is evidently greatest at an acid pH 4-5, that the adsorption of Omeprazole rises concomitantly with the increase in latex particles, and the time is the least influential factor.

Adsorption↗
PubMed2000

Adsorption-desorption of ondansetron on latex particles.

Ondansetron is a carbazol with antiemetic properties. It is used primarily to control nausea and vomiting caused by cytotoxic chemotherapy and radiotherapy, as well as for treatment of postoperative vomiting in gynecological surgery. Ondansetron has a shelf life of about 3 hr; hence, it is a matter of great interest to determine the ideal adsorption-desorption conditions for this drug on latex particles for designs of formulations (oral suspensions) containing polymers with the aim of delivering different drugs in a prolonged and controlled fashion. Time, pH, electrolytes, and concentration of the active principal at which maximal adsorption occurred were determined. Desorption of the drug from latex polymer particles was studied in different media. The results obtained suggest that this polymer is suitable as carrier of drug for obtained formulations of controlled release. The findings suggest that pH is the principal factor influencing the release of the ondansetron from Aquateric. The greatest release of drug occurs at acid pH, approximately 70% in the first hour; for the basic medium, the release is about 6%.

Adsorption↗
PubMed1999

Formation of ondansetron polymorphs.

We used differential scanning calorimetry, infrared spectrophotometry and 1H nuclear magnetic resonance imaging to search for polymorphs of ondansetron. Samples were tested under different conditions of temperature, pulverization and pH, and in different solvents. The factors identified as able to cause the formation of polymorphs were heating to different temperatures for different times, and the use of ethanol and methanol as solvents.

Antiemetics↗
PubMed1999

Development, formulation, and effectiveness testing of a silicone-based barrier-type hand cream.

We report the development, design, and results of effectiveness and acceptability testing of a hydrating, nutritive, barrier-type hand cream designed for severely damaged skin (including skin damaged by dermatological problems). We tested different silicone derivatives and a water-in-oil (W/O) silicone emulsifier to produce organoleptic qualities that would increase consumer acceptance of this type of W/O emulsion. Pharmacotechnical and effectiveness tests were done to check the stability and preservation of the formulas, their usefulness in improving dry skin, and acceptance by users. The results of pharmacotechnical testing were optimal. Although no active principle aimed specifically at dermatological problems was present in the final formulas, users reported notable subjective improvements in cracking and scaling.

Chemistry, Pharmaceutical↗
PubMed1999

[The usefulness of transjugular hepatic biopsy in the evaluation of liver disease in candidates for heart transplantation].

Heart transplantation is a universally accepted procedure in the treatment of terminal heart diseases. However, the presence of advanced liver disease in the potential receptors represents a contraindication for heart transplantation. On the other hand, the true diagnosis of liver disease not secondary to heart disease may be difficult requiring confirmatory liver biopsy. Nonetheless, percutaneous liver biopsy may be difficult to perform due to presence of coagulation alterations, marked dilatation of the hepatic veins, etc. The aim of this study was to evaluate the efficacy and safety of transjugular hepatic biopsy in the presence of severe coagulopathy in potential heart transplantation receptors with suspicion of liver disease and contraindication of percutaneous liver biopsy. Over a 9-year period, 350 potential heart transplantation patients were evaluated. In 23 patients (6.7%) transjugular hepatic biopsy was performed with aspiration needle followed by a hemodynamic study in 17 cases. The transjugular hepatic biopsy was completed in 22 cases (95.6%) with adequate material for the diagnosis being obtained in 21 (91.3% of the total cases indicated). Histologic study showed significant inflammatory infiltrates or alteration of the hepatic architecture in 4 patients (18%), all being positive for some viral markers (AgHBs or anti-HCV). The obtaining of a certain histologic diagnosis modified the consideration of liver disease as a definitive contraindication and allowed the performance of heart transplantation in 17 patients (73.9%). No complications were observed in association with the procedure. The transjugular hepatic biopsy is a feasible, effective and safe alternative for obtaining liver tissue in patients under evaluation for heart transplantation with suspicion of severe liver disease. The establishment of a correct histologic diagnosis may modify the clinical decision in an important number of patients.

Biopsy↗
PubMed1999

[The endoscopic placement of self-expanding metal prostheses as palliative treatment in colorectal stenosis of tumor origin].

BACKGROUND: The aim of this study was to retrospectively analyze the endoscopic placement of autoexpandible metallic prostheses of the colon carried out in our department as palliative treatment in patients with colorectal stenosis of tumoral origin. PATIENTS AND METHODS: From may, 1995 to august, 1998, autoexpandible metallic prostheses were placed in 14 patients (11 males and 3 females, mean age 64.5 years, range 41-92). All the patients presented tumoral stenosis by adenocarcinoma, 5 of which had been previously treated by surgery. RESULTS: All the stenoses were found in the rectum/sigma at less than 35 cm from the anal margin. In 7 patients endoscopic dilatation was performed prior to placement of the autoexpandible metallic prostheses. The prostheses used had a diameter of 18 mm and were of variable length. The placement of the prostheses was successfully achieved in all the patients except 2 (one due to technical difficulties and in the other because of early migration of the same, in both the autoexpandible metallic prostheses was placed without complications within 24 h). In two cases early complications were observed (14%): one case due to perforation and one to early migration. In two patients stenosis of the prostheses was observed during follow up and in a third patient late migration occurred. CONCLUSIONS: Endoscopic placement of autoexpandible metallic prostheses in patients with colorectal stenosis of tumoral origin is a simple technique with few complications and may be used as a definitive palliative treatment in these patients.

Adenocarcinoma↗
PubMed1999

[Arterial complications after liver transplantation: early and late forms].

Arterial complications after liver transplantation (OLT) was related with high morbimortality rates, with variable consequences on patient and graft survival. 234 patients who underwent 270 liver transplantation between april of 1990 and december 1996 have been evaluated. Arterial complications were detected in 34 patients (12.5%), hepatic artery stenosis in 10 patients (29.4%), thrombosis in 24 (70.6%) and aneurysm in 2 (5.9%). It was considered early artery complications those diagnosed at the first month after OLT, and late complications the latest ones. Diagnosis was realized by Doppler sonography in all cases, and confirmed by celiac arteriography in those with Doppler abnormal findings. Clinical appearance of early artery complications were as acute liver failure (61.1%) or graft disfunction (38.8%). On the other hand, late complications were diagnosed incidentally in 46% of the patients due a programmed Doppler follow up. Actuarial survival at 24 months was higher in patients with late arterial complication (50 vs 30%; p < 0.01). Therapeutic measures applied were retransplantation, surgical artery reconstruction and angioplasty. Early complications required more frequently retransplantation or surgical reconstruction. Risk factors related with artery complications development were analyzed, but not significant differences between both types of arterial complications were found. It is concluded that programmed follow up by Doppler or arteriography is necessary to make an earlier diagnose and to detect silent arterial complications.

Adult↗
PubMed1997

[Treatment with recombinant interferon alfa-2b of a patient with chronic hepatitis C and concomitant ulcerative colitis].

The case of a patient ulcerative colitis involving an autoimmune base who was treated with recombinant alpha-2b interferon for presenting chronic active hepatitis in relation to virus C is reported. Such treatment was achieved in addition to improving the hepatic disease normalizing the transaminases control the outbreak of ulcerative colitis that the patient was presenting from some days before beginning the treatment. Various aspects are discussed related to the autoimmunity in the ulcerative colitis and in the chronic C hepatitis and the exarcebation of autoimmune phenomena which may lead to interferon therapeutic. As a basis for the above and the review of the literature, we concluded that the existence of ulcerative colitis does not contraindicate the use of alpha-2b interferon in patient with chronic hepatitis, although special control of the disease should be carried out during the treatment period.

Adult↗
PubMed1990

A study of the electrokinetic and stability properties of nitrofurantoin suspensions. II: Flocculation and redispersion properties as compared with theoretical interaction energy curves.

The stability and redispersion properties of nitrofurantoin dispersions are experimentally studied using simple but reproducible techniques. Solutions of different electrolyte concentrations and pH values are employed as dispersing media. The pH appears to be a determinant factor in the properties studied. Thus, with all the electrolytes considered (NaCl, CaCl2, and AlCl3, almost optimum redispersion was achieved when the pH was maintained close to neutrality. However, the important effect of AlCl3 as compared with the other electrolytes is also clearly demonstrated. Especially interesting are the results obtained when 0.1% Carbopol is added to the suspensions. The important effect of this polymer on the surface charge of nitrofurantoin, mainly at pH 7, manifests in excellent redispersion of the suspensions with either of the electrolytes employed. Using simple expressions that approximate the equations proposed in the DLVO theory of interaction between colloidal particles, the variation of the total interaction energy between nitrofurantoin particles is calculated as a function of interparticle distance. The results are compared with the experimental determinations of the sedimentation and redispersion properties of nitrofurantoin. Although some discrepancies between theory and experiments are found, the results indicate a reasonable agreement between the general features of both.

Acrylic Resins↗
PubMed1990

Electrophoretic study of nitrofurantoin in aqueous suspensions. Effect of the addition of a polymeric thickener.

The electrophoretic mobility of nitrofurantoin (based on the microelectrophoresis method) has been studied in dilute dispersions of the drug. Specifically, the effect of NaCl, CaCl2 and AlCl3, pH, and a thickener, Carbopol 934, was determined. The electrophoretic mobility (mu) increases in absolute terms when the pH is raised between 3 and 9, although mu remains negative in this pH range. The variation of absolute mobility ([mu[) with NaCl concentration shows a pronounced maximum for a concentration of about 10(-4) M. However, when the concentration of CaCl2 in the medium is increased, [mu[ decreases steadily. The effect of AlCl3 concentration on the mobility is markedly influenced by the pH of the dispersing medium although a general trend is observed for mu to become more positive with increasing concentration of the salt. Finally, Carbopol 934 appears to impart an extra negative charge to the nitrofurantoin surface, since higher negative mobilities were measured in the presence of the polymer.

Acrylic Resins↗