Evaluación cualitativa y cuantitativa de enseñanza aprendizaje combinado, sobre alimentación del menor de dos años / Qualitative and quantitative assessment of combined teaching learning process on feeding of children under two years of age

INTRODUCCIÓN: la cátedra de pediatría con apoyo del Instituto de Investigación en Salud y Desarrollo de la UMSA, ha elaborado un módulo de enseñanza teórico práctico para brindar conocimiento científico actualizado sobre alimentación y nutrición del menor de dos años. Durante la última gestión universitaria se ha incursionado en la enseñanza virtual para incrementar el tiempo de lectura, y contar con mayor espacio para las actividades prácticas. MÁTERIALES Y MÉTODOS: el objetivo de este artículo es identificar las fortalezas y debilidades del proceso de enseñanza y aprendizaje (PEA) combinado; usando metodología cuantitativa (pre y post-prueba) y cualitativa (grupo focal). Se contó con un total de 39 estudiantes. La prueba de conocimientos post intervención tuvo un puntaje de 771 mayor que la previa (p=0,000 ((IC 95% 642,35 - 901,23); y se respondió en menor tiempo (-219,43 segundos p=0.0000 (IC 95% (146,98 ­ 291,88). Un 81% de estudiantes estaba en el límite o por encima de lo que se consideró mínimo adecuado de facilidades informáticas. El grupo focal evidencio dificultades en el portal virtual, como muchos pasos para el ingreso, la saturación del servicio y otras; se dieron múltiples sugerencias para mejorar el módulo. RESULTADOS: este estudio demuestra que además de adquirir conocimientos, los estudiantes se han involucrado en los diferentes aspectos PEA; en base a sus sugerencias se ha comenzado a realizar cambios incluyendo la introducción de herramientas digitales de uso colaborativo como Wiki. CONCLUSIÓN: se concluye que el PEA combinado aplicado en la catedra de pediatría de la UMSA mejora la adquisición de conocimientos y prácticas sobre lactancia materna y alimentación complementaria del menor de dos años.

INTRODUCTION: the pediatric department with the support of the Institute of Research in Health and Development of the UMSA has developed a practical and theoretical teaching module to provide updated scientific knowledge on food and nutrition for children under two years of age. During the last university year, virtual teaching has been introduced to increase reading time, and to have more space for practical activities. MATERIAL AND METHODS: the objective of this article is to identify the strengths and weaknesses of the combined Learning Teaching Process using quantitative (pre and post-test) and qualitative methodology (focus group); 39 students participated in the study. In the post-intervention knowledge test obtained a score of 771 higher than the one prior to intervention (p = 0.000 ((95% CI 642.35 - 901.23), and spent shorter time in answers (-219.43 seconds p = 0.0000 (95% CI % (146.98 - 291.88). A total of 81% of students were in the limit or above what was considered adequate or minimum computer facilities. The focus group evidenced difficulties in the virtual portal, as many steps for the entrance, the saturation of the service and others, multiple suggestions were given to improve the module. RESULTS: this study shows that in addition to acquiring knowledge, students have been involved in the different aspects of the Teaching Learning Process (TLP). Based on their suggestions, changes such as the introduction of collaborative digital tools (Wiki) have been made. CONCLUSIONS: the article concludes indicating that the combined TLP applied in the pediatric department of the UMSA improves the students' acquisition of knowledge and practices on breastfeeding and complementary feeding of the child two years.

Cianobacterial bloom and animal mass mortality in a reservoir from Central Argentina.

Piedras Moras reservoir (32° 10'27" S and 64° 16' 29" W; 832 ha), integrates a series of artificial lakes belonging to the Rio Tercero basin (Córdoba, Argentina). During March 2009 an algal bloom occurred, coinciding with several animal species mortality, mainly wild birds. The goal of this work was to establish the trophic status of the reservoir in relation to that mortality. Variables were evaluated in situ (temperature and water transparency) and samples were taken in order to identify algal species, Chl-a concentration (spectrophotometry) and toxins - total microcystines- (inmuno-enzymatic assay, ELISA). Histopathology studies were made on Fulica sp. A strong heterogenity in water transparency was observed, and "patches" of Potamogeton berteroanus distributed all along the lake, with Secchi disk minimal and medium values of 0.15 and 0.94 m. Chl-a concentration oscillated from 35.7 to 320.9 mg.m-3. Predominant phytoplankton species were Anabaena spiroides and Microcystis aeruginosa (Cyanophyceae). Water temperature was 27.8 °C (±0.88). Maximal value of total microcystine concentration was 0.23 µg.L-1. Chl-a concentration at the moment when mass mortality occurred (2.022 mg.m-3), and histopathological observations, strongly suggest that the animals' death was due to cianotoxins.

Cianobacterial bloom and animal mass mortality in a reservoir from Central Argentina

Piedras Moras reservoir (32° 10'27" S and 64° 16' 29" W; 832 ha), integrates a series of artificial lakes belonging to the Rio Tercero basin (Córdoba, Argentina). During March 2009 an algal bloom occurred, coinciding with several animal species mortality, mainly wild birds. The goal of this work was to establish the trophic status of the reservoir in relation to that mortality. Variables were evaluated in situ (temperature and water transparency) and samples were taken in order to identify algal species, Chl-a concentration (spectrophotometry) and toxins - total microcystines- (inmuno-enzymatic assay, ELISA). Histopathology studies were made on Fulica sp. A strong heterogenity in water transparency was observed, and "patches" of Potamogeton berteroanus distributed all along the lake, with Secchi disk minimal and medium values of 0.15 and 0.94 m. Chl-a concentration oscillated from 35.7 to 320.9 mg.m-3. Predominant phytoplankton species were Anabaena spiroides and Microcystis aeruginosa (Cyanophyceae). Water temperature was 27.8 °C (±0.88). Maximal value of total microcystine concentration was 0.23 g.L-1. Chl-a concentration at the moment when mass mortality occurred (2.022 mg.m-3), and histopathological observations, strongly suggest that the animals' death was due to cianotoxins.

O reservatório de Piedras Moras (32° 10'27" S e 64° 16' 29" W; 832 ha) faz parte de uma série de lagos artificiais que estão localizados na bacia do rio Tercero (Córdoba, Argentina). Durante março de 2009, ocorreu um florescimento maciço de cianobactérias que resultou na morte de muitas espécies de animais, especialmente aves aquáticas silvestres. O objetivo deste trabalho foi o de estabelecer o estado trófico do reservatório em função desta mortalidade. As variáveis foram avaliadas in situ (temperatura e transparência da água). Foram coletadas amostras para analisar as espécies de algas encontradas nos florescimentos. Foram determinados chl-a (espectrofotometria) e toxinas (microcistinas totais - ensaio imunoenzimático ELISA). Estudos histopalógicos foram realizados em Fulica sp. Uma grande heterogeneidade em transparência de água foi observada e agrupamentos de Potamogeton berteroanus estavam distribuídos em todo o reservatório com valores mínimos e médios do disco de Secchi de 0,15 a 0,54 m. Concentrações de chl-a oscilaram de 35,7 a 320,9 mg.m-3. As espécies fitoplanctônicas dominantes identificadas foram Anabaena spiroides e Microcystis aeruginosa (Cyanophyceae). A temperatura da água foi de 27,8 °C (±0.88). O valor máximo de concentração de microcistinas foi de 0,23 µg.L-1. A concentração de chl-a, quando ocorreu a mortalidade em massa (2,022 mg.m-3), e as lesões histopatológicas indicam que a mortalidade de animais foi devida a cianotoxinas.

Toxoplasma gondii ADP-ribosylation factor 1 mediates enhanced release of constitutively secreted dense granule proteins.

Toxoplasma gondii dense granules are morphologically similar to dense matrix granules in specialized secretory cells, yet are secreted in a constitutive, calcium-independent fashion. We previously demonstrated that secretion of dense granule proteins in permeabilized parasites was augmented by the non-hydrolyzable GTP analogue guanosine 5'-3-O-(thio)triphosphate (GTPgammaS) (Chaturvedi, S., Qi, H., Coleman, D. L., Hanson, P., Rodriguez, A., and Joiner, K. A. (1998) J. Biol. Chem. 274, 2424-2431). As now demonstrated by pharmacological and electron microscopic approaches, GTPgammaS enhanced release of dense granule proteins in the permeabilized cell system. To investigate the role of ADP-ribosylation factor 1 (ARF1) in this process, a cDNA encoding T. gondii ARF1 (TgARF1) was isolated. Endogenous and transgenic TgARF1 localized to the Golgi of T. gondii, but not to dense granules. An epitope-tagged mutant of TgARF1 predicted to be impaired in GTP hydrolysis (Q71L) partially dispersed the Golgi signal, with localization to scattered vesicles, whereas a mutant impaired in nucleotide binding (T31N) was cytosolic in location. Both mutants caused partial dispersion of a Golgi/trans-Golgi network marker. TgARF1 mutants inhibited delivery of the secretory reporter, Escherichia coli alkaline phosphatase, to dense granules, precluding an in vivo assessment of the role of TgARF1 in release of intact dense granules. To circumvent this limitation, recombinant TgARF1 was purified using two separate approaches, and used in the permeabilized cell assay. TgARF1 protein purified on a Cibacron G3 column and able to bind GTP stimulated dense granule secretion in the permeabilized cell secretion assay. These results are the first to show that ARF1 can augment release of constitutively secreted vesicles at the target membrane.

Toxoplasma gondii: conserved protein machinery in an unusual secretory pathway?

The protozoan parasite Toxoplasma gondii has a very specialized secretory apparatus. In this review we will discuss how different methodological approaches, including morphological studies, biochemistry and genetics, are revealing a novel secretory organization, whose function is performed, mainly, by a highly conserved protein machinery found in mammalian cells.

Sterol composition and biosynthesis in Trypanosoma cruzi amastigotes.

A detailed analysis of the endogenous sterols present in the clinically relevant intracellular (amastigote) stages of Trypanosoma cruzi, is presented. The parasites were grown in cultured Vero cells in the absence or presence of different sterol biosynthesis inhibitors, including the C14alpha demethylase inhibitor ketoconazole and two inhibitors of delta24(25)-sterol methyl transferase, 20 piperidin-2-yl-5alpha-pregnan-3beta-20-R-diol (22,26-azasterol) and 24-(R,S),25-epiminolanosterol. Amastigotes were isolated and purified from their host cells and neutral lipids were extracted, separated and analyzed by chromatographic and mass spectrometric methods. Control (untreated) amastigotes contained as main endogenous sterols 24-methyl-cholesta-7-en-3beta-ol (ergosta-7-en-3beta-ol) and its 24-ethyl analog, plus smaller amounts of their precursor, ergosta-7,24(28)dien-3beta-ol; these cells also contained cholesterol (up to 80% by weight of total sterols), probably derived from host cells. Amastigotes that proliferated in the presence of 10 nM ketoconazole (minimal inhibitory concentration, MIC) for 24 h had a sharply reduced content of endogenous 4-desmethyl sterols with a concomitant accumulation of 24-methyl-dihydrolanosterol and 24-methylene-dihydrolanosterol. On the other hand, amastigotes incubated during the same period of time with the two inhibitors of 24(25)-SMT at their respective MICs (100-300 nM) accumulated large amounts of C27 sterols whose structure suggested, in the case of 22,26-azasterol, that delta14 sterol reductase was also inhibited. Ketoconazole produced a dose-dependent reduction in the incorporation of [2-(14)C]-acetate into the parasite's endogenous C4-desmethyl sterols with an IC50 of 50 nM, indistinguishable from the value reported previously for the extracellular epimastigote form. Taken together, the results showed that amastigotes have a simpler sterol biosynthetic pathway than that previously described for epimastigotes, lacking both delta5 and delta22 reductases. They also suggest that the 100-fold higher potency of antifungal azoles as antiproliferative agents against amastigotes, when compared with epimastigotes, is most probably due to a smaller pool of endogenous sterols in the intracellular parasites.

Antiproliferative effects and mechanism of action of SCH 56592 against Trypanosoma (Schizotrypanum) cruzi: in vitro and in vivo studies.

We have investigated the antiproliferative effects of SCH 56592, a new experimental triazole, against Trypanosoma (Schizotrypanum) cruzi, the etiological agent of Chagas' disease in Latin America. SCH 56592 blocked the proliferation of the epimastigote form of the parasite in vitro at 30 nM, a concentration 30- to 100-fold lower than that required with the reference compounds ketoconazole and itraconazole. At that concentration all the parasite's endogenous sterols (ergosterol, 24-ethyl-cholesta-5,7,22-trien-3 beta-ol, and its 22-dihydro analogs), were replaced by methylated sterols (lanosterol and 24-methylene-dihydrolanosterol), as revealed by high-resolution gas chromatography coupled with mass spectrometry. This indicated that the primary mechanism of action of the drug was inhibition of the parasite's sterol C-14 alpha demethylase. Against the clinically relevant intracellular amastigote form, grown in cultured Vero cells at 37 degrees C, the MIC of SCH 56592 was 0.3 nM, again 33- to 100-fold lower than that of ketoconazole or itraconazole. In a murine model of acute Chagas' disease, SCH 56592 given at > or = 10 mg/kg of body weight/day for a total of 43 doses allowed 85 to 100% survival and 90 to 100% cure of the surviving animals, as verified by parasitological, serological, and PCR-based tests, while ketoconazole given at 30 mg/kg day allowed 60% survival but only 20% cure. In a murine model of chronic Chagas' disease, SCH 56592 was again more effective than ketoconazole, providing 75 to 85% protection from death, with 60 to 75% parasitological cures of the surviving animals, while no parasitological cures were observed with ketoconazole. The results indicate that SCH 56592 is the most powerful sterol biosynthesis inhibitor ever tested against T. cruzi and may be useful in the treatment of human Chagas' disease.

In-vitro antiproliferative effects and mechanism of action of the bis-triazole D0870 and its S(-) enantiomer against Trypanosoma cruzi.

We investigated the in-vitro antiproliferative effects and mechanism of action of both enantiomers of the bis-triazole derivative ICI 195,739 against epimastigotes and amastigotes of Trypanosoma cruzi, the aetiological agent of Chagas' disease. It has recently been shown that the R(+) enantiomer, D0870, can induce radical parasitological cure in murine models of the acute and chronic forms of the disease. D0870 dose-dependently affected the growth rate of the epimastigote form (IC50 = 0.1 microM; MIC = 1-3 microM). The S(-) enantiomer was much less active (IC50 = 3 microM). Growth arrest and cell lysis induced by D0870 coincided with the complete depletion of endogenous 4,14-desmethyl sterols and their replacement by 4,14-trimethyl and dimethyl sterols. The S(-) enantiomer produced qualitatively similar changes but to a lesser extent. D0870 inhibited the incorporation of radioactivity from [2-14C]acetate into the epimastigote's 4,14-desmethyl sterols with an IC50 of 50 nM while the corresponding concentration for the S(-) enantiomer was 3 microM. D0870 eradicated the intracellular (amastigote) form of the parasite from cultured Vero cells at 10 nM; a 100-fold higher concentration of the S(-) enantiomer was required to produce a similar effect, and deleterious effects of the host cells were observed at > 100 nM. At the MIC of D0870 the endogenous amastigote sterols (ergosta-7-en-3beta-ol, 24-ethyl-cholesta-7-en-3beta-ol and ergosta-7, 24(24[1])-dien-3beta-ol) were also largely replaced by lanosterol and 24-methyl-dihydrolanosterol. Combinations of D0870 and inhibitors of sterol delta24(25) sterol methyltransferase (such as 22,26-azasterol and 24(R,S),25-epiminolanosterol) acted synergically against the intracellular forms. Taken together these results indicate that, although both enantiomers have anti-T. cruzi activity, the specific activity of the R(+) enantiomer (D0870) is nearly two orders of magnitude higher than that of its S(-) analogue. However, as the in-vitro activity of D0870 is comparable to that of standard azoles, such as ketoconazole, its remarkable in-vivo antiparasitic activity may only be explained by its particular pharmacokinetic properties.

Naturally azole-resistant Leishmania braziliensis promastigotes are rendered susceptible in the presence of terbinafine: comparative study with azole-susceptible Leishmania mexicana promastigotes.

Leishmania braziliensis (isolate 2903) was naturally resistant to ketoconazole or the bis-triazole D0870, inhibitors of sterol C-14 demethylase, which produced only moderate effects on the proliferation of promastigotes at 10 microM. In contrast, Leishmania mexicana (isolate NR) was extremely susceptible to the azoles, as complete growth arrest and cell lysis were induced by incubation of the parasites with 0.05 microM concentrations of the drugs for 72 h. The opposite response was observed with terbinafine, an inhibitor of squalene epoxidase: L. braziliensis 2903 was three times more susceptible to the drug than L. mexicana NR (MICs of 5 and 15 microM, respectively). However, when the L. braziliensis stock was grown in the presence of 1 microM terbinafine, which by itself produced only marginal (< 10%) effects on growth, it became highly susceptible to the azoles, with an MIC of 0.03 microM. Analysis of cellular free sterols by high-resolution capillary gas chromatography coupled to mass spectrometry showed that 14-methyl sterols can support normal growth of L. braziliensis 2903 but not of L. mexicana NR. On the other hand, the higher susceptibility of the L. braziliensis isolate to terbinafine was correlated with a massive accumulation of squalene in the presence of the allylamine while no significant effects on L. mexicana sterol composition were observed at drug concentrations up to 1 microM. Thus, the > 300-fold increase in the susceptibility of L. braziliensis promastigotes to azoles in the presence of terbinafine was attributed to the combined effect of squalene and the methylated sterol precursors on the physical properties of the cell's membranes, leading to the loss of cell viability. Combination therapy with azoles and terbinafine in the treatment of human L. braziliensis infections deserves further study.

Cure of short- and long-term experimental Chagas' disease using D0870.

Chagas' disease, a protozoan infection by the kinetoplastid Trypanosoma cruzi, constitutes a major public health problem in Latin America. With the use of mouse models of both short- and long-term forms of the disease, the efficacy of D0870, a bis-triazole derivative, was tested. D0870 was able to prevent death and induced parasitological cure in 70 to 90 percent of animals, in both the short- and long-term disease. In contrast, currently used drugs such as nifurtimox or ketoconazole prolonged survival but did not induce significant curing effects. D0870 may be useful in the treatment of human long-term Chagas' disease, a condition that is currently incurable.

Attitudes of Bolivian pharmacists in dealing with diarrhea cases.

To help learn about the recommendations made by Bolivian pharmacists dealing with diarrhea cases, 498 pharmacies in three Bolivian cities (Cochabamba, El Alto, and La Paz) were visited by female interviewers who indicated they were seeking treatment for a child with diarrhea. Ninety-eight of the Cochabamba pharmacies were also visited by a male interviewer who indicated he was suffering from diarrhea and was seeking treatment. In response, fewer than 2% of the pharmacists recommended using oral rehydration salts (ORS), increasing fluid intake, or consulting a physician. Most recommended antimicrobials, antidiarrheals, or some combination of the two. At 329 (66%) of the pharmacies, oral rehydration salts were unavailable, and those that did have such salts rarely offered them to customers. At the time of the survey, pharmacists were not integrated into the Bolivian National Health Secretariat's training program for control of diarrheal diseases. Steps have since been taken to resolve this matter.

[Attitudes of Bolivian pharmacy distributors in a case of diarrhea]. / Actitudes de los expendedores de farmacias bolivianas frente a un caso de diarrea.

In order to learn the recommendations given for a case of diarrhea by persons who sell medications at pharmacies, interviewers visited pharmacies in three Bolivian cities and said they had a child suffering from diarrhea. Less than 2% of the vendors recommended using oral rehydration salts, increasing fluid intake, or consulting a doctor. Most of them recommended antibiotics, antidiarrheals, or both. Oral rehydration salts were not available in nearly two-thirds of the establishments visited, and those that had the salts rarely offered them. This study revealed the lack of integration of these professionals into the Health Secretariat's training program, and as a result activities were initiated to solve this problem.

Isolation and characterization of the thermoresistant gluconokinase from Escherichia coli.

It is known that two gluconokinases are inducibly expressed during the utilization of gluconate by E. coli. One is thermoresistant (activity stable for 3 h at 30 degrees C) and the other thermosensitive (losses 75% or more of its activity under the above conditions). The thermoresistant gluconokinase (EC 2.7.1.12) was isolated, purified and characterized for the first time from the E. coli mutant Ca26, a K12 derivative which lacks the thermosensitive activity. The enzyme was purified 43 fold with a recovery of 11%. The M(r) of the enzyme was 100 kDa with three equal subunits of approximately 29.5 kDa. The enzyme exhibited Michaelis-Menten kinetics and the Km values for gluconate and ATP were 0.02 mM and 0.045 mM respectively.

Acidosis tubular distal con perdida de bicarbonato. / Distal tubular acidosis with bicarbonate losing

Se estudiaron dos pacientes con diagnostico de acidosis tubular distal con perdida de bicarbonato. La estimacion de la reabsorcion fraccional de sodio durante la diuresis salina hipotonica mostro un aumento de la carga de sodio ofrecida al nefron distal y una menor capacidad de reabsorcion a nivel de este segmento, cuando se le compara con el valor control. En un paciente con diagnostico de acidosis tubular distal clasica se obtuvieron resultados similares, de lo cual se concluye que dicha prueba no permite localizar el sitio del defecto en la reabsorcion tubular de bicarbonato en la acidosis tubular distal clasica con perdida de bicarbonato