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Biomedical subjects

R Mejía

Publications and source records attributed to R Mejía.

At least 19 recordsLinked to original sources
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↗
PubMed2000

[Kikuchi-Fujimoto necrotizing lymphadenitis. Report of 2 cases].

Kikuchi-Fujimoto disease (KFD) is a form of necrotizing lymphadenitis. The disease is a usually benign, self limited cause of lymph node enlargement affecting predominantly young women. Several other clinical manifestations have been described, though the only consistent findings are a macular eruption and a fever. Occasionally, the disease has presented as a fever of unknown origin. Lymph node specimens show areas of necrosis without neutrophilic infiltration. Lymphocyte mediated apoptotic mechanisms are responsible for the necrosis observed. Clinically, it should be differentiated from many different conditions, including infections such as cat scratch disease and rheumatological diseases like Still's disease and Systemic Lupus Erythematosus. Pathologically, it should be differentiated from lymphomas. KFD is widely known in the Far East, but very rare in Latin America. As a matter of fact, we have only detected four reported cases from Argentina, Brazil and Chile. We here describe two additional cases from Argentina. Both occurred in young women. One had a mediastinal compromise and a recurrent course, only observed in 4% of cases. The second one had a classical cervical presentation. The diagnosis in both was made by lymph node biopsy, although, in areas of great prevalence, an aspiration may be sufficient to establish the disease. We anticipate that the real prevalence of this unusual disease is highly underrepresented.

Adult↗
PubMed1999

Escherichia coli membrane fluidity as detected by excimerization of dipyrenylpropane: sensitivity to the bacterial fatty acid profile.

A coordinated study of membrane fluidity and fatty acid composition has been carried out in Escherichia coli W3110. The lipid acyl chain profile of the bacteria, altered by growing cells in steady state at 30, 37, 42, or 45 degrees C, was determined by gas chromatography of the fatty acid methyl esters. In parallel experiments, total membranes obtained from cells of the above-mentioned cultures were labeled with dipyrenylpropane and their relative fluidity was measured on the basis of the excimer to monomer fluorescence intensity ratio of the fluorophore. It has been found that, at constant assay temperature, fluidity determined with dipyrenylpropane decreases gradually with the growth temperature increment, from 30 to 45 degrees C. Interestingly, when fatty acid composition is taken into account, fluidity increases linearly in the range under study, with the proportion of unsaturated fatty acyl chains, both variables being highly correlated (0.924 </= r(2) </= 0.996). Our results show that dipyrenylpropane is a reliable and quantitative indicator of changes in membrane fluidity, driven by modifications in the acyl chain composition of bacterial lipids.

Chromatography, Gas↗
PubMed1999

Fatty acid profile of Escherichia coli during the heat-shock response.

The possible changes in the fatty acid profile of Escharichia coli during heat-shock have been investigated. Bacteria growing in steady-state at 30 degrees C were subjected to an abrupt temperature upshift to 45 degrees C and held at the high temperature for various periods of time in order to elicit the heat-shock response. Fatty acid compositions of lipids extracted from samples taken at different times after the temperature upshift, as well as from cultures in steady-state at 30 and 45 degrees C, were determined by gas-chromatography. It has been found that the total unsaturates to total saturates ratio decreases gradually during heat-shock and that 30 min after the temperature jump, the reduction is equivalent to 57% of the difference between ratios corresponding to steady-state cultures at 30 and 45 degrees C. Consistent with this remodeling of lipid acyl chains, there is a decrease in the excimerization rate of the fluidity probe dipyrenylpropane incorporated into sonicated E. coli lipid extracts. Such modifications occur within the time-span of the heat-shock response, as judged from our previous measurements of the kinetics of change in heat-shock proteins induction ratio. Together, these results indicate that the control of membrane fluidity during the heat-shock response can be accounted for, at least in part, by an important change in the fatty acid composition of Escherichia coli lipids.

Escherichia coli↗
PubMed1999

[Family violence. The physician's role].

Family violence is mostly used against women. It is the cause of heavy psychological and physical damages as well as social and economic costs. It also has a repercussion on the future generations. Medical practitioners should be prepared to recognise these situations in order to give support, counsel and assistance to victims of abuse. Training in family violence should be included in pre and post courses in Medical School programs.

Domestic Violence↗
PubMed1996

[Physiopathology of preeclampsia].

Preeclampsia is a disease which appears only during pregnancy. It is highly widespread, and in the underdeveloped countries is the leading cause of maternal mortality. Nowadays it is considered a disease originated in the activation of the vascular endothelium triggered by placental ischemia. The latter is produced by a defect in the trophoblastic invasion of the spiral arteries of the uterus. Genetic, immunologic and biochemical causes have been postulated in the attempt to explain this defect in the trophoblastic implant, but whatever the cause, the endothelial activation produces several chemical mediators affecting the function of all organs, and then generating preeclampsia related syndromes. The prevention of this disease occupies a special place in research and there are numerous trials with aspirin and calcium being developed at the moment.

Arachidonic Acids↗
PubMed1995

Membrane fluidity of Escherichia coli during heat-shock.

The excimer-forming fluorophore dipyrenylpropane has been used to measure the relative fluidity of total membranes isolated from Escherichia coli grown at 30 or 45 degrees C, or exposed to a heat-shock from 30 to 45 degrees C for various periods of time. Parallel experiments were performed using [35S]methionine pulse-labeling of cells, to study the induction of heat-shock proteins (HSPs) at different times after the sudden change in E. coli growth-temperature from 30 to 45 degrees C. Results suggest that upon an abrupt temperature upshift from 30 to 45 degrees C, membrane fluidity adjustment to the steady-state level at the high temperature, takes place during the E. coli heat-shock response.

Escherichia coli↗
PubMed1994

[Retinopathy associated with acute pancreatitis].

Purtscher's retinopathy is a retinal lesion associated with different diseases such as cardiac aneurism, thoracic compression, bone fractures, post-trauma, pancreatitis and eclampsia. It consists in the appearance of white patches and retinal hemorrhage encircling an apparently normal optic disk. There is some controversy about its pathogenesis, but a probable cause for the development of this affection might be leukocyte emboli activated by complement. We present the case of a patient who developed a Purtscher's like retinopathy while he was being treated for pancreatitis.

Acute Disease↗
PubMed1989

[Post-cesarean uterine scar].

The American College of Obstetricians and Gynecologists recommends that women with one previous cesarean section be allowed a trial of labor. One of the exclusions to this recommendation are women with 2 or more previous cesarean section because of the risk of uterine dehiscence. We measured fibrosis in a sample obtained from the uterine scar region, finding the higher rate of fibrosis (35.7%) for the group with one previous cesarean section. We conclude that uterine scar shows no clear differences after one, two or more cesarean sections, so the risk of uterine scar dehiscence could be similar.

Adult↗
PubMed1978

[Contribution of Antioquia University to Latin American Dentistry].

The School of Dentistry of Antioquia University is one of the first institutions in Latin America to have developed and disseminated the ideas of integral clinical instruction and the delegation of functions to auxillary personnel. This article narrates some of the more important events that took place when these propositions were first advanced and put to the test. It also describes a few distinctive features of current clinical instruction at this School, including an evaluation system developed by members of the institution. The article comments on the trainig of auxiliary personnel and the scope of their functions. A brief review is given of the research on salt fluoridation that staff of Antioquia University have been conducting for several years in a number of Colombian towns. The results of this research to date are discussed.

Colombia↗