Biomedical subjects

A Avalos

Publications and source records attributed to A Avalos.

3 recordsLinked to original sources

PubMed2006

Association of serum pepsinogen with atrophic body gastritis in Costa Rica.

Individuals with atrophic gastritis (AG), especially atrophic body gastritis (ABG), are at increased risk of developing gastric cancer. Serum concentrations of pepsinogens (PG) have been proposed as markers for ABG. The aim of this study was to determine the risk factors for AG and ABG and the potential of using serum PG concentrations to detect ABG in a dyspeptic population in Costa Rica, which is one of the countries with the highest incidence and mortality rates of gastric cancer in the world. Seven biopsy specimens, a fasting blood sample and a questionnaire concerning sociodemographic factors were obtained from 501 consecutive dyspeptic patients. The serum PGI level and the PGI/PGII ratios were significantly lower in patients with ABG than in other groups (P<0.000). A cut-off point of 3.4 led to a sensitivity of 91.2% in identifying ABG, a negative predictive value of 98.1%, but a positive predictive value of only 11.2%. Helicobacter pylori were present in 93% of the patients and all those with peptic ulcers were positive. AG was associated with increased age, lower body mass index, high alcohol intake and low fruit consumption. ABG was associated with age, alcohol consumption and PGI/PGII<3.4. In dyspeptic patients with a high prevalence of H. pylori infection, serum PG levels provide an assessment of ABG but it is necessary to introduce other serological and genetic markers in order to achieve a better specificity. Those markers could be serum antibodies to H. pylori-CagA, cytokine gene polymorphisms or others.

Costa Rica↗

PubMed2001

[Printed material distributed by pharmaceutical propaganda agents].

Pharmaceutical sales representatives (drug reps) frequently visit 70% to 90% of physicians during their daily clinical practice and many consider the promotional printed material to be a major source of clinical information. We evaluated samples of the promotional printed material distributed to physicians by drug reps in order to determine whether the data contained in the promotional material is correct and supported by references accessible in Argentina. A consecutive sample of all the promotional material distributed by drug reps in the general internal medicine program (Hospital de Clínicas) was collected between March 15 and April 15, 2000. Reprints and monographs were excluded. Clinical information was reviewed by two general internists and compared to information in a major pharmacology textbook and in an electronic medical information program. References cited were reviewed for correct listing and accessibility in any of the four major medical libraries in Buenos Aires. Of the sixty-four pieces of promotional material collected, thirty were randomly selected and evaluated. In twenty one (70%) the therapeutic effect promoted in advertisement appeared in Goodman & Gilman's 9th edition textbook of pharmacology, in the pharmacology section of the Up-to-Date version 8.1 or in both. Only eighteen (60%) of the thirty promotional printed material evaluated had statements supported by cited references. From a total of 131 references cited in promotional materials, sixty (46%) were incorrectly listed according to the International Committee of Medical Journal Editors. These references were inaccessible. Of the 71 references correctly cited, 49 (69%) were not available in any of the four major medical libraries in Buenos Aires and 8 were available in only two of the libraries. Twenty-two references were reviewed, and in twelve of these (54%), the objective of the research study concurred with the statement of the promotional printed material. Adverse reactions, warnings about drug interactions and contraindications were absent from all promotional printed material. It can be concluded that the promotional printed material distributed by the drug reps in Buenos Aires are biased and provide misinformation more often than not. We recommend that practicing physicians routinely disregard promotional printed material as a source of clinical information.

Advertising↗

PubMed1987

Equivalence between Pfr and Cyclic AMP in the Induction of d-Usnic Acid Dehydrogenase in the Lichen Evernia prunastri.

d-Usnic acid dehydrogenase is induced in Evernia prunastri thalli by a supply of exogenous d-usnic acid in light. This effect is enhanced by red light pulses through a two step way: a very rapid increase of activity after the first 10 minutes of red light, which is not reversed by far-red light, and a slow enhancement following successive red light pulses at the beginning of each hour of incubation. The last response is completely reversed by far-red following red light. Although induction of the enzyme is not achieved in the dark, 0.1 and 0.5 millimolar cyclic AMP, or 0.1 millimolar dibutyryl cyclic AMP substitutes light action and, then, the enzyme is produced. In addition, phytochrome-far red-absorbing form-increases the amount of endogenously produced cyclic AMP and this effect is shown to be photoreversible when ethylenediaminetetraacetic acid is inhibiting adenylate cyclase.

Journal Article↗