[Analysis of a proposal for changing the educational paradigm in bacteriology and virology. Facultad de Ciencias Médicas, Universidad Nacional de Córdoba]

The productive character of the scientific thought points out a methodological means that include the demand of the students' job about the information and not his mere reception and reproduction. It is essential to give the students the opportunity of discovering the cognitive processes used in the production of the scientific knowledge. In this work, we present the result of the starting of a workshop dynamic in a basic subject, the students' answers, and the analysis of the subject. In the Chair of Medical Bacteriology and Virology of the School of Medical Sciences, the National University of Córdoba, 1700 students attended classes in 1997. The subject was developed with the activities that worked the same contents from two different learning conceptions: (I) workshop activity, non obligatory, constructive, and (II) theorico-practical activity, obligatory and traditional. Two voluntary and anonymous interviews were done about the valuation that the student gave to these two activities and their basis, one in the middle and the other at the end of the course. 90.55% classified the traditional activity as positive, and 9.45% as negative. Regarding the workshop activity, the 60.5% classified it as positive and the 39.5% as negative. The same developed content with two activities made possible the analysis of the impact that the two different methodologies produced on the students. The student's answer to the traditional activity was better than the workshop activity (p < 0.001). The differences in the student's acceptance between the two option revealed the major difficulty of an alternative methodological strategy in the current educational model.

Glutamate regulates kainate-binding protein expression in cultured chick Bergmann glia through an activator protein-1 binding site

The expression of the chick kainate-binding protein, a member of the ionotropic glutamate receptor family, is restricted to the cerebellum, specifically to Bergmann glia. Glutamate induces a membrane to nuclei signaling involved in gene expression regulation. Exposure of cultured chick Bergmann glia cells to glutamate leads to an increase in kainate binding protein and mRNA levels, suggesting a transcriptional level of regulation. The 5' proximal region of the chick kainate binding gene was cloned and transfected 4into Bergmann glia cells. Three main regulatory regions could be defined, a minimal promoter region, a negative regulatory region, and interestingly, a glutamate-responsive element. Deletion of this element abolishes the agonist effect. Moreover, electrophoretic mobility shift assays, cotransfection experiments, and site-directed mutagenesis clearly suggest that the glutamate effect is mediated through an AP-1 site by a Fos/Jun heterodimer. The present results favor the notion of a functional role of kainate-binding protein in glutamatergic cerebellar neurotransmission.

Proton pump inhibitor, clarithromycin and either amoxycillin or nitroimidazole: a meta-analysis of eradication of Helicobacter pylori

AIM

To perform a meta-analysis of studies comparing twice daily, one-week triple therapy with a proton pump inhibitor, clarithromycin (C) and amoxycillin (A) (PCA) vs. those using proton pump inhibitor, clarithromycin and a nitroimidazole (N) (PCN) for H. pylori eradication.

REVIEW METHODS

SELECTION CRITERIA

Comparative randomized trials of PCA vs. PCN were included.

DATA SOURCES

PubMed database and abstracts from congresses until September 1999.

STATISTICS

Meta-analysis was performed combining the Odds Ratios (OR) of the individual studies in a global OR (Peto method) both on an intention-to-treat (ITT) and on a per protocol (PP) basis.

RESULTS

Twenty-two studies fulfilled the inclusion criteria. Eighteen studies reported ITT and 20 PP analysis. Mean H. pylori eradication rates were 81% (95% CI: 79-83%) ITT, and 84% (82-86%) PP with PCA, and 81% (78-83%) ITT and 84% (82-86%) PP with PCN; the odds ratio for the effect of PCA vs. PCN was 1 (0.83-1.22) on an ITT, and 0.98 (0.8-1.2) on a PP basis. Subanalysis showed that mean H. pylori eradication efficacy with PC(250 b.d.)A was 81% (78-85%) ITT, vs. 86% (83-89%) with PC(250 b.d.)N. The odds ratio for this comparison was 0.68 (0.48-0.98). Finally, when comparing PC(500 b.d. )A against PC(250 b.d.)N ITT cure rates were 77% (74-80%), and 75% (72-78%) with an odds ratio of 1.18 (0.93-1.5).

CONCLUSION

Overall, one-week combination regimens of PCA and PCN present similar H. pylori eradication efficacy. Nevertheless, the PCN regimen obtains significantly better results when using low doses of C (250 mg b.d.).

Angiotensin I converting enzyme polymorphism in humans with age-associated memory impairment: relationship with cognitive performance

We compared the distribution of an insertion (I)/deletion (D) polymorphism coding for the angiotensin I converting enzyme (ACE) gene in 100 subjects fulfilling NIMH criteria for Age-associated memory impairment (AAMI) and 124 controls. We found significantly reduced prevalences of the ACE I/I genotype together with increases of the ACE D allele in the AAMI group. We further compared the neuropsychological performance of the AAMI group according to their ACE genotype. Those AAMI subjects presenting the ACE I/I genotype exhibited better performance on a measure of frontal lobe function. Our results suggest that the lack of the ACE I/I genotype and the presence of the ACE D allele are associated with memory impairment in the elderly.

A meta-analysis of short versus long therapy with a proton pump inhibitor, clarithromycin and either metronidazole or amoxycillin for treating Helicobacter pylori infection

BACKGROUND

Although triple therapies with a proton pump inhibitor, clarithromycin and either amoxycillin or metronidazole are the most widely accepted treatment for Helicobacter pylori infection, there is no consensus on how long treatment should be maintained for.

AIM

To evaluate whether increasing the length of triple therapies beyond 7 days improves treatment efficacy.

METHODS

An extensive search of the literature was performed. Reports of randomized trials comparing different lengths of therapy were selected. Short (7-day) vs. long (10/14-day) therapies were compared, and three-way comparison of 7-day vs. 10-day, 10-day vs. 14-day and 7-day vs. 14-day therapies was performed. Meta-analysis was conducted using conventional shareware (Review Manager 4.0). The Peto Odds Ratio using a fixed model analysis was calculated for each comparison.

RESULTS

Thirteen studies were identified. Pooled 10- to 14-day therapies achieved better results than 7-day schedules. In head-to-head comparisons, only 14-day therapies were significantly better than 7-day treatments. Improvement in cure rates ranged from 7 to 9%. Comparisons of 7-day vs. 10-day and 10-day vs. 14-day also showed a non-significant trend towards better cure rates with longer therapies.

CONCLUSIONS

Fourteen-day, proton pump inhibitor-based triple therapy achieves better results than 7-day schedules. Additional data are necessary to evaluate 10-day therapies.

Apo E influences declarative and procedural learning in age-associated memory impairment

Age-associated memory impairment (AAMI) is a clinical entity which was originally described to define memory problems linked to normal aging. Apolipoprotein E and ACE genes have both been associated with cognitive impairment in aging and dementia. The purpose of this study was to investigate memory and executive functions in AAMI according to the genetic background. We found that subjects carrying the Apo E epsilon4 allele exhibit lower memory performance on tests of both declarative and procedural memory. We did not find differences on frontal lobe tests. These findings give further support to the hypothesis concerning a genetic susceptibility for cognitive impairment in aging.

[Extracurricular activities of adolescents useful for smoking prevention programs. OCTOPUS team]

BACKGROUND

The cigarette smoking habit continues to be prevalent to a greater degree than would be desirable among teenagers. Innovative prevention programs are needed. This descriptive cross-sectional study sets out the behavior variables related to the cigarette smoking habit and the extracurricular activities in which teenagers are most frequently involved which are useful for setting out extracurricular prevention programs.

METHODS

The data was collected by means of a questionnaire validated in a representative sample of school age youths (ages 10-11 and 13-14) from Asturias. The variables entailed in cigarette smoking were analyzed using the regression method.

RESULTS

The starting smoker percentage is 14.5%-42.5%, regular smokers totaling 1.1% and 12.4%, respectively. Two models were constructed with the variables significantly related to smoking behavior, which are properly classified into smoker/non-smoker by 98.85% and 91.39% of the children, by ages. The environmental variables (availability of cigarettes and alcoholic beverages and regular visits to places entailing risk) are the major aspects comprising the model. The most common extracurricular activities are: watching TV, reading and listening to music and watching or playing sports.

CONCLUSION

The findings provide keys to planning extracurricular activities tailored to fit in with the activities most popular among teens: TV commercials and ads on music media (CD's, tapes, etc.) and printed information mailed directly to teens at their homes, with messages conveyed by opinion-leaders among teens in the fields of sports, music and television.

Changes in GluR4 expression induced by metabotropic receptor activation in radial glia cultures

The expression of neurotransmitter receptors in glial cells has suggested a regulatory role of these cells in synaptic function. In radial glia, glutamate receptors elicit a cascade from the membrane to the nucleus and a consequent change in gene expression. In order to gain insight into this process, we address the question of whether receptor activation leads to changes in the repertoire of AMPA/KA glutamate receptor subunits in Bergmann and Müller glial cells. Of the subunits investigated, only GluR4 was up-regulated in Bergmann glial cells both at mRNA and protein levels. In contrast, in Müller glial cells Glu treatment leads to a reduction in GluR4 mRNA and protein expression. Both effects are receptor-mediated and must probably involve group I of metabotropic glutamate receptors. Accordingly, using Northern blot analysis and RT-PCR we detected the expression of both mGluR1 and mGluR5 transcripts in the cultured cells. Our results confirm that glutamate receptors in Bergmann and Müller cells modulate gene expression and further strengthen a plausible role of glial cells in long-lasting changes in the central nervous system.

NMDA receptors in cultured radial glia

The expression of the NMDA subtype of glutamate receptors was investigated by Western blot analysis and RT-PCR in cultured chick Bergmann and Müller glial cells. Using subunit-specific antibodies directed to the carboxy terminus of the rat NMDAR2A/B we detected the expression of the NMDAR2 subunit in both kinds of culture. The functional subunit of the NMDA receptor, NMDAR1, was detected by means of RT-PCR. These results, together with our previous functional characterization of NMDA receptors in radial glia, provide conclusive evidence for the expression of functional NMDA receptor/channels in Bergmann and Muller glia cells. Our findings strengthen the notion of a modulatory role of glial cells in synaptic transmission.

[Nutrient and food consumption by ages and gender in school children from the Community of Madrid (CAENPE)]

The objective of the present work was to know the consume of foodstuffs and nutrients among schoolchildren in the Madrid Autonomous Community and also the relative contribution of each group of foodstuffs to the overall intake of macronutrients. This study had a sectional observational design involving 2,608 children (51% males and 49% females) with ages ranging from 6 to 14 years who were randomly recruited from conglomerate of schools, according to socio-economic status and rural/urban residence. The inquiry on nutrients in 4 non consecutive days was analyzed (2 "24 hour-recall" and 2 "intake recall").

RESULTS

a) the consume of proteins, lipids, and carbohydrates represented 17%, 43% and 40% of the total caloric value, respectively; b) the intake of meats, sausages, sweets, tidbits, and processed products was very high. This fact is in origin of the excessive total and saturated lipid intake; c) there was a scarce intake of vegetables, cereals and potatoes among children of all ages and dairy products in children older than 12 years; d) the intake of legumes, eggs and fruits was appropriate; e) males consumed proportionally higher amounts than females of the following groups of foodstuffs: cereals, sweets and tidbits. The consume of meat, sausages, fish, eggs, potatoes, dry fruits and dairy products was similar in both sexes. Females consumed proportionally more fat foodstuffs, vegetables, fruits, legumes and processed products; f) females consumed a diet with a still higher lipid and protein content than males. These findings can serve as a basis to develop educational guidelines with a practical impact on family and school menus.

Hereditary angioedema: an infrequent cause of abdominal pain with ascites

Patients with hereditary angioedema have episodes of local swelling, usually affecting the face, extremities, upper airway, and gastrointestinal tract. Only infrequently does it cause recurrent abdominal pain (with or without ascites); however, because it has potentially life-threatening complications, an early diagnosis is important. We describe a case of type I hereditary angioedema (a quantitative deficit of C1 inhibitor), the sole initial symptom of which was severe recurrent and self-limited abdominal pain, accompanied by ascites during these episodes. During a 4-yr period of treatment with danazol, the patient was virtually asymptomatic, despite levels of C4 and C1 inhibitor that remained below normal limits, and there have been no major side effects that could be attributed to treatment with androgens.

[Food consumption and the nutritional status of schoolchildren of the Community of Madrid (CAENPE): general methodology and overall food consumption. Consumo de alimentos y estado nutricional de la población escolar]

The CAENPE study (Food Consumption and Nutritional State of the School Population) was a transversal observational study funded and promoted by the Directorate-General of Food Hygiene in the Ministry of Health, implemented in 1991-93, with the main aim of quantifying food consumption in the school population (6-14 years of age) in the Regional Community of Madrid, together with an anthropometric study and nutritional analysis of that population. This project sets our the General Methodology for the study, paying particular attention to the sampling design, to ensure that the sample is representative of the community, and the results of the overall consumption of food and its comparison with recommended diet and other population studies. Quantification shows a high and rising consumption of meat, meat products, sweets, snacks and prepared dishes, suitable consumption of eggs, legumes and fruit and a notable lack of greens, vegetables and potatoes. The basic results underline the need to introduce educational measures with practical effect on home and school menus.

[Pneumothorax in patients with AIDS]

METHODS

From January 1986 to 31 November 1993, 354 cases of AIDS (CDC criteria 1987) were diagnosed. The possible existence of spontaneous pneumothorax at any time during the evolution and its presumed cause were evaluated.

RESULTS

During the period studied, 7 (1.9%) of AIDS patients presented pneumothorax. The existence of a pulmonary infection was proven in 6: 3 pneumonia by Pneumocystis carinii, 2 bacterial pneumonia (Streptococcus pneumoniae and Pseudomonas sp.) and 1 tuberculosis. One patient presented a Pneumocystis carinii pneumonia 3 months prior to the pneumothorax. In the study period 88 (22.8%) of the AIDS patients presented pneumonia by Pneumocystis carinii and 181 (51.1%) presented tuberculosis. The rate of pneumothorax in patients with a history or presence of pneumonia by Pneumocystis carinii was of 4.5% and 0.5% in patients with tuberculosis.

CONCLUSIONS

The development of pneumothorax is relatively frequent in patients with AIDS in our area. As found in other series, its most frequent cause was Pneumocistis carinii pneumonia, despite the high incidence of tuberculosis.

AMPA/KA receptor expression in radial glia

The expression of four genes (GluR 1; 2; 3; 4) encoding functional subunits of the alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA)/low affinity kainate (KA) subtype of glutamate receptors was investigated in chick radial glia, namely Bergmann and Müller glial cells, using Northern blot analysis with oligonucleotide probes. Both cell types expressed the transcripts GluR 1; 3; 4, whereas the GluR 2 mRNA could not be detected. The synaptic localization of these receptors, their ion-channel properties and their regulation further strengthen the putative role of glial cells in the modulation of synaptic efficacy and plasticity.

Vitamin E and ventricular fibrillation threshold in myocardial ischemia

The effect of vitamin E on the ventricular fibrillation threshold was studied in an experimental model of acute myocardial ischemia. An anterior thoracotomy was performed on 23 anesthetized Wistar rats. The ventricular fibrillation threshold was measured. Vitamin E was then administered intravenously to an experimental group (n = 11) and a placebo to a control group (n = 12). The ventricular fibrillation threshold was measured again. Finally, the left anterior descending coronary artery was occluded, producing anteroapical myocardial ischemia. The ventricular fibrillation threshold was measured again. This threshold did not vary significantly when vitamin E or the placebo was administered before occluding the coronary artery but after the occlusion a threshold decrease in the placebo group was observed, whereas no such decrease was manifested in the vitamin E-treated group. The results suggest that vitamin E prevents ventricular fibrillation in acute myocardial ischemia in rats.

Plasma membrane regionalization and compaction of mouse cleaving embryos: effect of microtubule and microfilament inhibitors

Two-cell embryos were incubated during 44 h in media containing either microtubule or microfilament inhibitors. The lowest doses that inhibit cleavage were found to be 0.5 micrograms/ml for colchicine and colcemid, 5 micrograms/ml for cytochalasin B and 0.5 micrograms/ml for cytochalasin D. After incubation with the minimal doses of these drugs, embryos were either fixed immediately or transferred to fresh media without drugs and cultured for different times before fixation. Then, embryos were processed for scanning electron microscopy. Following incubation with microtubule inhibitors, less than 10% of the embryos were compacted and about 20% became so in fresh medium. Regionalization was revealed by the cytochemical demonstration of alkaline phosphatase or 5'-nucleotidase on the apposing surfaces of blastomeres in 50% of the embryos, including all those that were compacted. By scanning microscopy microvilli were seen evenly distributed on the embryo surface, as they are observed in normal 2-cell embryos. Following incubation with microfilament inhibitors, few embryos were compacted and about 90% compacted within 4 h in fresh medium. Alkaline phosphatase activity was detected between blastomeres in all compacted embryos and in one half of those still uncompacted. Scanning microscopy showed patches of microvilli on the outer surface which had become otherwise smooth. During incubation in fresh medium, microvilli concentrated in two large patches placed at the antipodes of the embryo. From these results we conclude that cytokineses is not required for cell membrane regionalization, that blastomeres regionalize before they compact, that microtubule and microfilament inhibitors affect differently the array of microvilli on the external surface of arrested embryos.

Cell membrane regions in preimplantation mouse embryos

Cell membrane regions characterized by alkaline phosphatase activity are described in cleaving mouse embryos and early blastocysts. Enzyme activity is demonstrated by light and electron microscopy, from the late 4-cell stage onwards, on the cell surfaces between blastomeres but not on the outer surface of the embryo. Experiments with dissociated morulae show that this is probably not an artifact due to the retention of the enzyme reaction product between the blastomeres. With the electron microscope the activity is also demonstrated in crystalloid bodies within the cytoplasm. The localization and growth during cleavage of cell membrane regions with enzyme activity is interpreted as the result of new cell membrane formation and/or as a relation of the crystalloid bodies with the cell membrane through the cortical system of microtubules and filaments.

Cell membrane and cell junctions in differentiation of preimplanted mouse embryos

Cell membrane and cell junctions in differentiation of preimplanted mouse embryos, (membrana celular y uniones celulares en la diferenciación del embrión de ratón antes de la implantación). Arch. Biol. Med. Exper. 10: 130-134, 1976. The development of cell junctions that seal the peripheral blastomeres could be a decisive step in the differentiation of morulae into blastocysts. The appearance of these junctions is studied by electron microscopy of late morulae and initial blastocysts. Zonulae occludentes as well as impermeability to lanthanum emulsion precedes the appearance of the blastocel and hence might be considered as one of its necessary causes.

Cell volume and DNA content of Trypanosoma lewisi and T. mega in vitro

Two species of trypanosomes were harvested at a comparable stage in vitro development, just as cell division was ceasing and cell length had become maximal and its variability minimal. At this stage, T. mega displayed both a larger cell volume than T. lewisi (27.5 vs. 14.3 mu-2) and a greater DNA content (0.23 vs. 0.048 pg/cell).