RESUMEN

BACKGROUND: Medical curricula have historically been designed in a top-down approach, usually excluding students. While Delphi panels have been used as a tool for medical education curricula design, none have been conducted in Ecuador. In addition, no such approach has ever included students both as panelists and researchers. MATERIAL AND METHODS: Four Delphi panels were developed and conducted using a participatory approach that allowed medical students to take part both as expert panelists and researchers: specifically, students developed the questionnaire and conducted a qualitative synthesis. Questionnaire responses were anonymized and dispatched online to panelists. The information was organized and collected to develop the qualitative syntheses and prepare the final statements. RESULTS: Thirty-two medical students participated between February and May 2018. A total of 32 questions were developed, corresponding to five different categories. For some questions, consensus was reached; for other questions, general statements were obtained.Discussion and conclusion: Developing the questionnaire, responding to it and analyzing the answers allowed students to raise significant concerns regarding medical education topics proposing relevant policy and curricula change. Participatory Delphi panels can be an efficient tool to obtain organized feedback, improve student class involvement, and promote research skills.

Asunto(s)

RESUMEN

In Argentina, drinking water for c.a. 10% of the population has arsenic (As) concentrations higher than those recommended by WHO (10 µg L-1). Reverse osmosis (RO) appears as an immediate and effective solution for As remediation. However, this process has a residual flow known as "rejection" or "concentrate" where dissolved species are more concentrated than in the feed flow. In this study, phytoremediation with subsurface horizontal-flow constructed wetlands (CW) was proposed to reduce As concentration in the RO residues. Experiments were carried out during 419 days at room temperature and using a continuous regime (flow of 36 L d-1, As concentration around 85 µg L-1) of RO rejection from a water treatment plant located in Buenos Aires province, Argentina. The study was performed using prototypes planted with Cyperus haspan (PA), Juncus effusus (PB) and a mix of inert gravel and laterite (substrate) that was used as a control (PC). Results showed that after a stabilization time, As removal (%) was between 30% and 80% in the CW planted with J. effusus and between 10 and 40% with C. haspan. As concentration along CW showed similarities between the prototypes PC and PA. The cumulative mass of As was 62%, 34% and 27% for PA, PB and PC, respectively. The contribution of C. haspan and J. effusus during the experimental time was between 12 and 67% and 22 to 87%, respectively. The bioaccumulation and translocation factors indicated that for J. effusus the accumulation is more important than the translocation process (1.6 and 0.2, respectively), while for C. haspan both factors were similar (1.1 and 1.0, respectively). Results suggested that this technology has the potential for an efficient and environmentally sustainable alternative to RO rejection treatment and disposal regarding As concentration.

Asunto(s)

Asunto(s)

RESUMEN

The dual-purpose bovine system represents 98.4% of the bovine livestock of Veracruz, the main cattle-producing state of Mexico. This system supplies calves to meat companies, a sector in which Veracruz has been the national leader in the last decade. The objective of the present study was to analyze the effect of the altitudinal zonation of farms on livestock technology and productivity in a microbasin of the Gulf of Mexico where small farms predominate. Structured interviews were applied to producers located in three altitudinal zones (at average altitudes of 50, 140, and 450 m, respectively, for lower, middle, and upper zones). Sample size was 135 farms having similar land surface (within a range of 15-22 ha). The results indicated multiple differences among farms located in the three zones. Farms in the middle and lower zones presented higher productive indicators than those in the upper zone. Differences in herd structure and management resulted in important differences in productivity, income, and profits in milk and calf production. We concluded from this study that altitudinal zonation in Veracruz had a clear effect on the differentiation of small farms, which are representative of dual-purpose cattle. The upper zone performs cattle activity under conditions with greater disadvantages in the analyzed region.

Asunto(s)

RESUMEN

The objective of this study was to estimate the size and chemical quality of the total organic C stock and its partition between above-belowground plant parts and soil at sites with different plant cover induced by sheep grazing in the arid Patagonian Monte. This study was conducted at six representative sites with increasing signs of canopy disturbance attributed to grazing pressure. We used faeces density as a proxy of grazing pressure at each site. We assessed the total plant cover, shrub and perennial grass cover, total standing aboveground biomass (AGB), litter mass and belowground biomass (BGB) at each site. We further estimated the content of organic C, lignin and soluble phenols in plant compartments and the content of organic C, organic C in humic substances (recalcitrant C) and water soluble C (labile C) in soil at each site. Total plant cover was significantly related to grazing pressure. Standing AGB and litter mass decreased with increasing canopy disturbance while BGB did not vary across sites. Total organic C stock and the organic C stock in standing AGB increased with increasing total plant, shrub, and perennial grass cover. The organic C stock in litter mass increased with increasing total plant and shrub cover, while the organic C stock in BGB did not vary across sites. Lignin content in plant compartments increased with increasing total and shrub cover, while soluble phenols content did not change across sites. The organic C stock and the water soluble C content in soil were positively associated with perennial grass cover. Changes in total plant cover induced by grazing pressure negatively affected the size of the total organic C stock, having minor impact on the size of belowground than aboveground components. The reduction of perennial grass cover was reflected in decreasing chemical quality of the organic C stock in soil. Accordingly, plant managerial strategies should not only be focused on the amount of organic C sequestered but also on the chemical quality of organic C stocks since C chemistry could have an important impact on ecosystem functioning.

Asunto(s)

RESUMEN

Grouping species may provide some degree of simplification to understand the ecological function of plants on key ecosystem processes. We asked whether groups of plant species based on morpho-chemical traits associated with plant persistence and stress/disturbance resistance reflect dominant plant growth forms in arid ecosystems. We selected twelve sites across an aridity gradient in northern Patagonia. At each site, we identified modal size plants of each dominant species and assessed specific leaf area (SLA), plant height, seed mass, N and soluble phenol concentration in green and senesced leaves at each plant. Plant species were grouped according with plant growth forms (perennial grasses, evergreen shrubs and deciduous shrubs) and plant morphological and/or chemical traits using cluster analysis. We calculated mean values of each plant trait for each species group and plant growth form. Plant growth forms significantly differed among them in most of the morpho-chemical traits. Evergreen shrubs were tall plants with the highest seed mass and soluble phenols in leaves, deciduous shrubs were also tall plants with high SLA and the highest N in leaves, and perennial grasses were short plants with high SLA and low concentration of N and soluble phenols in leaves. Grouping species by the combination of morpho-chemical traits yielded 4 groups in which species from one growth form prevailed. These species groups differed in soluble phenol concentration in senesced leaves and plant height. These traits were highly correlated. We concluded that (1) plant height is a relevant synthetic variable, (2) growth forms adequately summarize ecological strategies of species in arid ecosystems, and (3) the inclusion of plant morphological and chemical traits related to defenses against environmental stresses and herbivory enhanced the potential of species grouping, particularly within shrubby growth forms.

Asunto(s)

RESUMEN

The objective of this study was to analyze the effect of grazing disturbance on the amount and the spatial distribution (vertical and horizontal) of root biomass and soil organic carbon (SOC) in order to evaluate whether grazing alters the belowground storage of organic carbon (C) in arid rangelands of the Patagonian Monte. We selected three representative sites (3 ha each) with low, moderate and high grazing disturbance located far, mid-distance and near the watering point, respectively, in rangelands submitted to sheep grazing for more than 100 years. We assessed the canopy structure and identified the four most frequent plant patch types at each site. We selected four replications of each patch type and extracted a soil sample (0-30 cm depth) underneath the canopy and in the middle of the nearest inter-patch bare soil area in winter and summer. We assessed the root and soil dry mass and the respective organic C concentration in each sample and then we estimated the total belowground organic C storage at each site. Total plant and perennial grass cover were lower with high than low grazing disturbance while the reverse occurred with dwarf shrub cover. High grazing disturbance led to the increase in total root biomass in the whole soil profile of patch areas and in the upper soil of inter-patch areas. SOC was higher in patch than in inter-patch areas at all sites but at both areas was reduced with high grazing disturbance. This was probably the result of the low total plant cover and the low and recalcitrant contribution of above and below-ground plant litter to soils at sites with high grazing disturbance. Accordingly, these changes did not result in variations in the total belowground organic C storage. We concluded that high grazing disturbance did not affect the total belowground organic C storage but led to changes in the spatial patterning of this organic C storage (i.e shifting from soil to roots).

Asunto(s)

RESUMEN

A Secretaria Municipal de Saúde de São Paulo garante o acesso universal com equidade aos serviços de saúde pelo Sistema Integrado de Gestão e Assistência à Saúde (SIGA-Saúde), que dispõe de Módulos de agenda Local e Regulada, Fila de Espera e Registro de Atendimento Reduzido. Este registro informatizado possibilita conhecer a real necessidade de saúde da população.

Asunto(s)

RESUMEN

A Secretaria Municipal de Saúde de São Paulo garante o acesso universal com equidade aos serviços de saúde pelo Sistema Integrado de Gestão e Assistência à Saúde (SIGA-Saúde), que dispõe de Módulos de agenda Local e Regulada, Fila de Espera e Registro de Atendimento Reduzido. Este registro informatizado possibilita conhecer a real necessidade de saúde da população

Asunto(s)

RESUMEN

A Secretaria Municipal de Saúde de São Paulo garante o acesso universal com equidade aos serviços de saúde pelo Sistema Integrado de Gestão e Assistência à Saúde (SIGA-Saúde), que dispõe de Módulos de agenda Local e Regulada, Fila de Espera e Registro de Atendimento Reduzido. Este registro informatizado possibilita conhecer a real necessidade de saúde da população(AU)

Asunto(s)

RESUMEN

Phenol-ammonia clusters with more than five ammonia molecules are proton transferred species in the ground state. In the present work, the excited states of these zwitterionic clusters have been studied experimentally with two-color pump probe methods on the nanosecond time scale and by ab initio electronic-structure calculations. The experiments reveal the existence of a long-lived excited electronic state with a lifetime in the 50-100 ns range, much longer than the excited state lifetime of bare phenol and small clusters of phenol with ammonia. The ab initio calculations indicate that this long-lived excited state corresponds to a biradicalic system, consisting of a phenoxy radical that is hydrogen bonded to a hydrogenated ammonia cluster. The biradical is formed from the locally excited state of the phenolate anion via an electron transfer process, which neutralizes the charge separation of the ground state zwitterion.

Asunto(s)

RESUMEN

The aim of this paper is to describe metabolic and endocrine alterations in the male, partners of infertile couples. One hundred and six consecutive men were taken in order to analyze their serum samples. Each serum sample was analyzed by duplicate for luteinizing hormone (LH), follicle-stimulating hormone (FSH), estradiol (E2), free-testosterone (T), 17 alpha-hydroxyprogesterone (17OHP), androstenedione (A), dehydroepiandrosterone-sulphate (DHEA-S), prolactin (PRL), insulin, glucose, total cholesterol and triclylcerides. The data analysis evidenced different metabolic or endocrine alterations in the group. A dysplipidemia incidence of 65% was found (isolated hypercholesterolemia, isolated triglyceridemia or both), where 80% of these patients were younger than 40 years. There was no correlation with obesity, overweight any endocrine alteration and the type of sperm alterations. There was a positive correlation between E2 and FSH (r = 0.67, p < 0.0001) in the group of 106 patients, which remained significant in the group of hyperestrogenic men (n = 27, r = 0.68, p < 0.0001), but not in men with normal serum estrogen levels (n = 79, r = 0.10, NS). Other alterations: obesity in 18%, overweight in 30.2%, diabetes mellitus 4.7%, glucose intolerance 15%, hypertension 26% (14/53), hypergonadotropic hypogonadism 3.8% (one of them with an Emty Sella syndrome). Unexpectedly only nine patients (8.4%) out of the 106 consecutive patients recluted did not have any of the metabolic or endodrine abnormalities here described. These are more significant since 83% of the patients are younger than 40 years. The most interesting non previously described finding was the positive correlation observed between E2 and FSH when estradiol levels exceeds 50 pg/mL.

Asunto(s)

RESUMEN

OBJECTIVE: The purpose of the study was to assess the effects of Escherichia coli STa (heat stable) toxin on isolated human myometrial response to oxytocin. METHODS: One hundred and sixteen muscle strips were obtained from the lower uterine segment of 42 women undergoing cesarean section at term. Amniotic membranes and decidua were excluded. Uterine contractility in response to cumulative doses of E. coli STa toxin was recorded, as well as uterine response to cumulative doses of oxytocin before and after incubation with STa toxin or vehicle. The 50th percentile effective oxytocin concentration (EC50) of muscle strips with and without spontaneous activity before and after the incubation with STa toxin or vehicle was calculated. A paired t test was used for comparison. RESULTS: Muscle strips with and without spontaneous activity responded to cumulative doses of oxytocin before and after the incubation with STa toxin or vehicle. No differences in contraction force, duration, or frequency were noted between the groups (P > 0.05). Furthermore, this toxin was not able to induce uterine contractility when tested alone. CONCLUSIONS: The inability of this toxin to affect myometrial response to oxytocin in this study may be due to the absence of amnion cells, chorion, or decidua. Other possible explanations for the lack of response are discussed.

Asunto(s)

RESUMEN

Considerando que el hábito de fumar y sus consecuencias, constituye uno de los problemas más graves de Salud Pública de nuestros tiempos, efectuamos el presente estudio analítico de casos y controles, sobre los factores de riesgo asociados al consumo de cigarrillos en escolares adolescentes. Se realizó en tres colegios oficiales que imparten II Ciclo de Secundaria, ubicados en la ciudad de Panamá, durante el período de sept.-dic., 1996. La muestra estuvo constituida por los 100 casos y 200 controles. De los factores de riesgo estudiados, se destacaron en orden de importancia: la actitud aprobatoria de los padres (OR=7.45; L.C=1.37-53.2; P=0.004); presencia de fumadores en el grupo de amigos (OR=5.06; LC=2.91-8.82; P=0.000); fiestas reuniones de amigos (OR=4.35; LC=2.52-7.53; P=0.000); presencia de fumadores en casa (OR=3.92; LC=2.27-6.79; P=0.000); influencia de amigos en la decisión de fumar (OR=3.44; LC=2.01-5.91; P=0.000); edad de 17-19 años (OR=2.16; LC=1.28-3.65; P=0.002); ingreso familiar mensual mayor de B/.300.00 (OR=2.03; LC=1.14-3.59; P=0.008). No se encontraron asociaciones estadísticamente significativas con el sexo

Asunto(s)

RESUMEN

To investigate the nature of neuroendocrine disturbances of the hypothalamo-pituitary-gonadal axis in idiopathic male infertility, we studied 14 infertile men with oligoasthenozoospermia (OLIGO) and 15 age-, body mass index-, and community-matched euspermic controls by blood withdrawal at 10-min intervals for 12 h to encompass basal (8-h) and exogenous GnRH-stimulated (4-h) pulsatile release of LH and FSH (by immunoradiometric assay) as well as testosterone (by RIA). Deconvolution analysis was used to estimate endogenous LH and FSH half-lives, secretory burst frequency, amplitude, duration, and mass. OLIGO men exhibited normal serum concentrations of total, free, and percent dialyzable testosterone and estradiol, but distinct dynamic alterations within the LH and FSH axes; namely (P < 0.05), 1) a prolonged half-life of LH (OLIGO, 95 +/- 19 min; control, 80 +/- 9.3 min) and a reduced half-life of FSH (OLIGO, 260 +/- 79 min; control, 320 +/- 93 min); 2) a low LH, but normal FSH, secretory burst frequency (OLIGO, 12 +/- 3.4; control, 15 +/- 3.0 LH pulses/day); 3) a decreased serum testosterone peak frequency (OLIGO, 16 +/- 4.3; control, 21 +/- 3.2 peaks/day); and 4) an amplified mass of LH (1.1- to 1.3-fold higher in OLIGO) and FSH (2.4- to 2.7-fold higher in OLIGO) secreted per burst basally as well as after GnRH injection. These disturbances were readily distinguishable from the neuroendocrine dysregulation described in other states of male hypogonadotropism (e.g. uremia, fasting, and aging).

Asunto(s)

RESUMEN

Idiopathic oligo-asthenozoospermia is among the most frequent causes of male infertility and has a not very well understood etiopathogenesis. To obtain valuable information about the role of some endocrine factors in the etiology of this kind of infertility, information that is not easy obtain by the traditional analytical methods, we applied some recently proposed mathematical algorithms to analyze with more exactitude the importance of the secretory pulses of three hormones, luteinizing hormone (LH), follicle stimulating hormone (FSH) and testosterone (T). Serum samples were obtained every 10 min for 12 h, from 15 fertile normospermic men and 14 infertile patients with idiopathic oligo-asthenozoospermia; the concentration profiles of FSH and T were analyzed by IRMA and RIA, and the immuno-and bioactive LH concentrations were quantified by IRMA and bioassay (JCEM 42:958, 1976). To assess the pituitary stores of LH and FSH, after 8 h of spontaneous secretion we administered (2 h apart) 2 intravenous pulses containing 10 micrograms of a GnRH analog, and the sampling continued as described. Hormonal pulsatility was assessed by a computerized cluster analysis method (Am J Phys 250:E486, 1986) an by the multiple parameters deconvolution method (JCEM 66: 1291, 1988). In the infertile patients we found a significant diminution in the length and frequency of LH pulses, compared with the normospermic men. However, LH half life, the interpulse interval, the amplitude and the mass secreted per pulse rose in the infertile males compared with the controls. The increase in the LH half life suggests the secretion of a more acidic isoform of this hormone in the infertile group. After the GnRH injection the LH secreted mass and mean concentration rose significantly in both groups; this effect was higher in the infertile oligo-asthenozoospermic men. In this group we also found a decrease in the bioactive LH interpulse interval and therefore more pulses during the sampling interval, that produced a higher concentration of this kind of hormone in these patients. Oligo-asthenozoospermic men secreted approximately 70% more bioactive LH as a response to the first GnRH injection than the normal controls. The desensitization observed with immunoactive LH (diminution in the mass secreted after the second GnRH bolus compared with the first one) was also observed with bioactive LH. In the infertile men group we found a significant reduction in the FSH half life compared with the normospermic controls; this fact suggests that, contrarily to the results observed with LH, a more basic isoform is secreted in these patients.(ABSTRACT TRUNCATED AT 400 WORDS)

Asunto(s)

RESUMEN

The purpose of this study was to establish a blood platelet aggregation model that would permit "in vivo" (New Zealand rabbits) evaluation of hemodynamic and microscopic parameters. The platelet aggregation was induced by the administration of collagen I.V. 75 micrograms/kg/min, which produced a decrease of systolic arterial pressure from mean = 69 to mean = 55 mm Hg and diastolic pressure from mean = 43 to mean = 27 mm Hg, with ventricular increase from mean = 25 to mean = 41 mm Hg. Aspirin, dypiridamol or sulfinpyrazone was administered 10 mg/kg, half hour before the administration of collagen and prostacycline 100 mg/kg/min starting 3 minutes before until 10 minutes after the collagen injection. With the joint administration of collagen and aspirin, collagen and dypiridamol both systolic and diastolic arterial pressure were lowered with no modification in the ventricular values. No hemodynamic changes were observed with the joint administration of sulfinpyrazone-collagen or prostacycline-collagen. Histology demonstrated multiple vascular lung thrombosis with the administration of collagen and in less intensity when jointly administered with an antiaggregant drug. This model permits to measure hemodynamically and histologically pro and antiaggregant substances.

Asunto(s)

RESUMEN

The calcium, magnesium, zinc, iron, and copper content found in scalp hair of 40 children with mental retardation were compared with 37 healthy normal children who were between the ages of 4 and 14 yr. The hair of children with mental retardation showed significantly lower levels of iron, copper, and magnesium (p less than .001) and higher levels of calcium (p less than .001). The zinc content did not differ between the two groups. The differences in levels of hair trace elements between normal children and those with mental retardation could be of particular interest in the investigation of the cause of mental retardation among children.

Asunto(s)

Asunto(s)