Impact of digital technologies upon teaching and learning in higher education in Latin America: an outlook on the reach, barriers, and bottlenecks.

Digital technology and literacy can heighten the transformation of teaching and learning in higher education institutions (HEIs). This study uncovers the extent to which digital technologies have been used to advance the teaching and learning process in HEIs, and the barriers and bottlenecks to why it may not have been effectively implemented across the HEIs. The study used nine selected countries in Latin America (LATAM) based on the main focus of the educators, commercial, and financial investors; to show the level of impact/implications of computer technologies on the teaching and learning processes. We applied a two-step (mixed) methodology (through a quantitative and qualitative lens) for the research investigation, using data collected from survey we administered to faculty members in HEIs across the different countries in LATAM. In turn, we implemented a Text Mining technique (sentiment and emotional valence analysis) to analyze opinions (textual data) given by the participants to help determine challenges and obstacles to using the digital technologies for teaching and learning in the region. Quantitatively, we applied a Kruskal-Wallis H-test to analyze the collected multiple choice and ranked items in the questionnaire in order to identify prominent factors that consummately influence the reach, barriers, and bottlenecks, and where the differences may lie across the different LATAM countries. The results show that the users upheld the emphasis on lack of training, infrastructures and resources, access to internet and digital platforms, as the main challenges to the teaching-learning process. The study also empirically discussed and shed light on critical factors the HEIs, particularly in LATAM, should resolve and adopt in support of the decision-making strategies, operational policies and governance, financial investments, and policymaking, at a time when "digital technologies" have become an inevitable and indispensable part of education and learning.

Effects of COVID-19 lockdown on sleep duration, sleep quality and burnout in faculty members of higher education in Mexico / Efeitos do lockdown da COVID-19 na duração e qualidade do sono e sintomas de burnout no corpo docente do ensino superior no México

Abstract This paper aims to assess the differences and associations of the effect of COVID-19 on sleep habits, sleep quality, and burnout symptoms among faculty members of higher education in Mexico. This was a cross-sectional study with a total sample of 214 faculty members of higher education from Mexico between May 18th and June 10th of 2020. We applied questionnaires containing sociodemographic and specific questions regarding sleep habits, sleep quality, and burnout symptoms. The results show that during COVID-19 faculty members delayed their bedtime and rise time. No change was found with weekdays time in bed, however, during weekends, time in bed was more than an hour shorter. Social jetlag decreased significantly during COVID-19. Furthermore, during COVID-19, those who reported low sleep quality were more likely to report higher symptoms of emotional exhaustion and those who slept less on weekends were more likely to report higher symptoms of depersonalization. These results suggest that the COVID-19 pandemic may have an effect on sleep and sleep quality and burnout symptoms of faculty members from higher education in Mexico.

Resumo Este trabalho visa avaliar as diferenças e associações do impacto da COVID-19 sobre hábitos de sono, qualidade do sono e sintomas de burnout entre os docentes de ensino superior no México. Trata-se de um estudo transversal, com amostra total de 214 docentes, realizado entre 18 de maio e 10 de junho de 2020. Foram aplicados questionários contendo questões sociodemográficas e específicas sobre hábitos de sono, qualidade do sono e sintomas de burnout. Os resultados mostram que durante a pandemia os docentes atrasaram a hora de dormir e acordar. Nenhuma alteração foi observada com relação ao tempo de semana na cama, porém nos finais de semana o tempo na cama era mais de uma hora menor. O jetlag social diminuiu significativamente durante a COVID-19. Além disso, durante a pandemia, aqueles que relataram baixa qualidade do sono eram mais propensos a relatar sintomas mais fortes de exaustão emocional, e aqueles que dormiam menos nos fins de semana eram mais propensos a relatar sintomas mais fortes de despersonalização. Esses resultados sugerem que a pandemia de COVID-19 pode ter um efeito sobre a qualidade do sono e causar sintomas de burnout nos integrantes do corpo docente do ensino superior no México.

Effects of COVID-19 lockdown on sleep duration, sleep quality and burnout in faculty members of higher education in Mexico.

This paper aims to assess the differences and associations of the effect of COVID-19 on sleep habits, sleep quality, and burnout symptoms among faculty members of higher education in Mexico. This was a cross-sectional study with a total sample of 214 faculty members of higher education from Mexico between May 18th and June 10th of 2020. We applied questionnaires containing sociodemographic and specific questions regarding sleep habits, sleep quality, and burnout symptoms. The results show that during COVID-19 faculty members delayed their bedtime and rise time. No change was found with weekdays time in bed, however, during weekends, time in bed was more than an hour shorter. Social jetlag decreased significantly during COVID-19. Furthermore, during COVID-19, those who reported low sleep quality were more likely to report higher symptoms of emotional exhaustion and those who slept less on weekends were more likely to report higher symptoms of depersonalization. These results suggest that the COVID-19 pandemic may have an effect on sleep and sleep quality and burnout symptoms of faculty members from higher education in Mexico.

Towards teaching analytics: a contextual model for analysis of students' evaluation of teaching through text mining and machine learning classification.

Recent trends in educational technology have led to emergence of methods such as teaching analytics (TA) in understanding and management of the teaching-learning processes. Didactically, teaching analytics is one of the promising and emerging methods within the Education domain that have proved to be useful, towards scholastic ways to make use of substantial pieces of evidence drawn from educational data to improve the teaching-learning processes and quality of performance. For this purpose, this study proposed an educational process and data mining plus machine learning (EPDM + ML) model applied to contextually analyze the teachers' performances and recommendations based on data derived from students' evaluation of teaching (SET). The EPDM + ML model was designed and implemented based on amalgamation of the Text mining and Machine learning technologies that builds on the descriptive decision theory, which studies the rationality behind decisions the learners are disposed to make based on the textual data quantification and statistical analysis. To this effect, the study determines pedagogical factors that influences the students' recommendations for their teachers, what role the sentiment and emotions expressed by the students in the SET play in the way they evaluate the teachers by taking into account the gender of the teachers. This includes how to automatically predict what a student's recommendation for the teachers may be based on information about the students' gender, average sentiment, and emotional valence they have shown in the SET. Practically, we applied the Text mining technique to extract the different sentiments and emotions (intensities of the comments) expressed by the students in the SET, and then utilized the quantified data (average sentiment and emotional valence) to conduct an analysis of covariance and Kruskal Wallis Test to determine the influential factors, as well as, how the students' recommendation for the teachers differ by considering the gender constructs, respectively. While a large proportion of the comments that we analyzed (n = 85,378) was classified to be neutral and predominantly interpreted to be positive in nature considering the sentiments (76.4%), and emotional valence (88.2%) expressed by the students. The results of our analysis shows that for the students' comments which contain some kind of positive or negative sentiment (23.6%) and emotional valence (11.8%); that females students recommended the teachers taking into account the sentiments (p = .000). While the males appear to be slightly borderline in terms of emotions (p = .056) and sentiment (p = .077). Also, the EPDM + ML model showed to be a good predictor and efficient method in determining what the students' recommendation scores for the teachers would be, going by the high and acceptable values of the precision (1.00), recall (1.00), specificity (1.00), accuracy (1.00), F1-score (1.00) and zero error-rate (0.00) which we validated using the k-fold cross-validation method, with 63.6% of optimal k-values observed. In theory, we note that not only does the proposed method (EPDM + ML) proves to be useful towards effective analysis of SET and its implications within the educational domain. But can be utilized to determine prominent factors that influences the students' evaluation and recommendation of the teachers, as well as helps provide solutions to the ever-increasingly need to advance and support the teaching-learning processes and/or students' learning experiences in a rapidly changing educational environment or ecosystem.

Technology-mediated teaching and learning process: A conceptual study of educators' response amidst the Covid-19 pandemic.

The COVID-19 pandemic has disrupted many areas of the human and organizational ventures worldwide. This includes new innovative technologies and strategies being developed by educators to foster the rapid learning-recovery and reinstatement of the stakeholders (e.g., teachers and students). Indeed, the main challenge for educators has been on what appropriate steps should be taken to prevent learning loss for the students; ranging from how to provide efficient learning tools/curriculum that ensures continuity of learning, to provision of methods that incorporate coping mechanisms and acceleration of education in general. For several higher educational institutions (HEIs), technology-mediated education has become an integral part of the modern teaching/learning instruction amidst the Covid-19 pandemic, when digital technologies have consequently become an inevitable and indispensable part of learning. To this effect, this study defines a hybrid educational model (HyFlex + Tec) used to enable virtual and in-person education in the HEIs. Practically, the study utilized data usage report from Massive Open Online Courses (MOOCs) and Emotions and Experience Survey questionnaire in a higher education setting for its experiments. To this end, we applied an Exponential Linear trend model and Forecasting method to determine overall progress and statistics for the learners during the Covid-19 pandemic, and subsequently performed a Text Mining and Univariate Analysis of Variance (ANOVA) to determine effects and significant differences that the teaching-learning experiences for the teachers and students have on their energy (learning motivation) levels. From the results, we note that the hybrid learning model supports continuity of education/learning for teachers and students during the Covid-19 pandemic. The study also discusses its innovative importance for future monitoring (tracking) of learning experiences and emotional well-being for the stakeholders in leu (aftermath) of the Covid-19 pandemic.

The impact of the COVID-19 pandemic on students' feelings at high school, undergraduate, and postgraduate levels.

The COVID-19 pandemic and the enforced restrictions have harshly affected educational sectors in 161 countries around the world. With more than 1.6 billion students away from normal school life, the crisis threatens the teaching and learning processes and the students' emotional health. Herein, we present the result of a careful assessment of the feelings of over 13,000 students at high school, undergraduate, and postgraduate levels across 36 campuses over 8 subsequent weeks from the onset of the COVID-19 pandemic. The results indicate a general low energy level and dominance of negative feelings among the students regardless of their academic levels. We have recorded 5 responses (being anxious, stressed, overwhelmed, tired, and depressed) as the most frequently reported feelings in the time of lockdown. Overall, 14% of those who have reported to suffer from these feelings have also identified a need for professional help in managing their feelings throughout the quarantine period. The current study also presents several strategies to combat the undesirable consequences of COVID-19 pandemic.

Does professors' gender impact how students evaluate their teaching and the recommendations for the best professor?

This study examined the impact of the professors' gender according to a student evaluation of teaching (SET) in a private university. The study took place in a private university (n = 103,833) on six different campuses in the north region of Mexico. The distribution of the professors' gender was analyzed according to semesters, campuses, and schools. Our findings suggested that when undergraduates evaluated their professors on specific criteria concerning teaching performance, they expressed their opinion regardless of the professors' gender. However, when being asked for a single overall evaluation, as whether they would recommend the professor as one of their best professors, the students tended to favor male professors over their female peers by a slight margin. While such perceptions might not be representative of the actual teaching quality, it would be interesting in the future to delve deeper into the causes of possible biases.

Hernia diafragmática congénita de presentación tardía / Late-presenting congenital diaphragmatic hernia

La hernia diafragmática congénita de presentación tardía (HDCT) es una entidad infrecuente, representa del 5 a 20 % de todos los casos de hernia diafragmática congénita. La presentación clínica, diagnóstico y tratamiento difiere de la hernia de presentación neonatal, dada la ausencia de hipoplasia e hipertensión pulmonar. El amplio espectro clínico de la presentación tardía o su hallazgo radiológico incidental, pueden plantear un desafío diagnóstico; la demora en su detección y abordaje aumentan la morbimortalidad y ensombrecen el pronóstico. Presentamos el caso de una escolar de 8 años de edad a quien se le diagnostica una hernia diafragmática congénita izquierda y se hace revisión del diagnóstico, tratamiento y pronóstico de la enfermedad.

The late-presenting congenital diaphragmatic hernia is a rare entity that corresponds to the 5 - 20% of all congenital diaphragmatic hernia cases. The clinical manifestations ,diagnosis and treatment differ from the neonatal presentation in the absence of pulmonary hypoplasia and pulmonary hypertension. The wide clinical spectrum of the late-presenting diaphragmatic hernia or its incidental finding on radiological images can lead to a challenging diagnosis. The delay in the detection and approach increases the morbidity and mortality, and darkens the prognosis. We are presenting a case of an eighth year-old scholar who is diagnosed with a congenital left diaphragmatic hernia, as well as a review of the diagnosis, treatment and prognosis of this pathology.

[Influence of serum levels of vitamin D on IgE response in schoolchildren with asthma in poor communities]. / Influencia de los niveles séricos de vitamina D sobre la respuesta IgE en niños escolares con asma en comunidades pobres.

BACKGROUND: Asthma is a common disease in the world and vitamin D (Vit-D) has been associated with the presence and severity of this disease. OBJECTIVE: To establish the association between levels of Vit-D and IgE response in schoolchildren with asthma living in four cities in Colombia. METHODS: Case-control study in 1340 schoolchildren (687 asthmatic and 653 controls) from communities in extreme poverty in Barranquilla, Cartagena, Santa Marta, and Montería. Serum concentrations of Vit-D, total IgE, and anti-Dermatophagoides farinae, Periplaneta americana, and Ascaris lumbricoides (AL) specific IgE were measured. RESULTS: Controls reported higher concentrations of Vit-D [61.9 ± 28.4 ng/mL] than cases [53 ± 23.3 ng / mL] (p < 0.05). Total IgE was higher in cases (p < 0.05). Only anti-AL IgE showed a clear difference: in controls, optical density was 0.27 ± 0.25; in cases, 0.22 ± 0.24 (p < 0.05). Vit-D showed differences between cases and controls in each population. CONCLUSIONS: An association could not be demonstrated between Vit-D deficiency and asthma, as total IgE was elevated in patients and controls. The results suggest that Vit-D influences the specif IgE response in poor asthmatic children in areas endemic for helminthiasis.

Antecedentes: El asma es una enfermedad frecuente en el mundo y la vitamina D (Vit-D) se ha asociado con la presencia y severidad de esta enfermedad. Objetivo: Establecer la asociación entre los niveles de Vit-D y la respuesta IgE en escolares con asma residentes de cuatro ciudades colombiananas. Métodos: Estudio de casos y controles en 1340 escolares (687 asmáticos y 653 controles) de comunidades en extrema pobreza de Barranquilla, Cartagena, Santa Marta y Montería. Se midieron las concentraciones séricas de Vit-D, IgE total e IgE específica anti Dermatofagoides farinae, Periplaneta americana y Ascaris lumbricoides (AL). Resultados: Los controles reportaron concentraciones mayores de Vit-D [61.9 ± 28.4 ng/mL] que los casos [53 ± 23.3 ng/mL] (p<0.05). La IgE total fue mayor en los casos (p<0.05). Solo IgE anti-AL mostró una diferencia clara: controles, densidad óptica 0.27 ± 0.25; casos 0.22 ± 0.24 (p<0.05). La Vit-D presentó diferencias entre casos y controles en cada población. Conclusiones: No se pudo demostrar la asociación entre deficiencia de Vit-D y asma, dado que la IgE total estuvo elevada en los pacientes y en los controles. Los resultados sugieren que la Vit-D influye en la respuesta IgE específica en niños asmáticos pobres en zonas endémicas para helmintiasis.

The oxidative fermentation of ethanol in Gluconacetobacter diazotrophicus is a two-step pathway catalyzed by a single enzyme: alcohol-aldehyde Dehydrogenase (ADHa).

Gluconacetobacter diazotrophicus is a N2-fixing bacterium endophyte from sugar cane. The oxidation of ethanol to acetic acid of this organism takes place in the periplasmic space, and this reaction is catalyzed by two membrane-bound enzymes complexes: the alcohol dehydrogenase (ADH) and the aldehyde dehydrogenase (ALDH). We present strong evidence showing that the well-known membrane-bound Alcohol dehydrogenase (ADHa) of Ga. diazotrophicus is indeed a double function enzyme, which is able to use primary alcohols (C2-C6) and its respective aldehydes as alternate substrates. Moreover, the enzyme utilizes ethanol as a substrate in a reaction mechanism where this is subjected to a two-step oxidation process to produce acetic acid without releasing the acetaldehyde intermediary to the media. Moreover, we propose a mechanism that, under physiological conditions, might permit a massive conversion of ethanol to acetic acid, as usually occurs in the acetic acid bacteria, but without the transient accumulation of the highly toxic acetaldehyde.

Purification and characterization of the membrane-bound quinoprotein glucose dehydrogenase of Gluconacetobacter diazotrophicus PAL 5.

Acetic acid bacteria oxidize a great number of substrates, such as alcohols and sugars, using different enzymes that are anchored to the membrane. In particular, Gluconacetobacter diazotrophicus is distinguished for its N2-fixing activity under high-aeration conditions. Ga. diazotrophicus is a true endophyte that also has membrane-bound enzymes to oxidize sugars and alcohols. Here we reported the purification and characterization of the membrane-bound glucose dehydrogenase (GDHm), an oxidoreductase of Ga. diazotrophicus. GDHm was solubilized and purified by chromatographic methods. Purified GDHm was monomeric, with a molecular mass of 86 kDa. We identified the prosthetic group as pyrroloquinoline quinone, whose redox state was reduced. GDHm showed an optimum pH of 7.2, and its isoelectric point was 6.0. This enzyme preferentially oxidized D-glucose, 2-deoxy-D-glucose, D-galactose and D-xylose; its affinity towards glucose was ten times greater than that of E. coli GDHm. Finally, Ga. diazotrophicus GDHm was capable of reducing quinones such as Q 1, Q 2, and decylubiquinone; this activity was entirely abolished in the presence of micromolar concentrations of the inhibitor, myxothiazol. Hence, our purification method yielded a highly purified GDHm whose molecular and kinetic parameters were determined. The possible implications of GDHm activity in the mechanism for reducing competitor microorganisms, as well as its participation in the respiratory system of Ga. diazotrophicus, are discussed.

Homicídios na região das Américas: magnitude, distribuição e tendências, 1999-2009 / Homicides in the Americas region: magnitude, distribution and trends, 1999-2009

O objetivo do estudo foi descrever a magnitude e a distribuição da mortalidade por homicídios nas Américas e analisar suas tendências. Foram analisados óbitos por homicídios (X85 a Y09 e Y35) de 32 países das Américas, período 1999-2009, registrados no Sistema de Informações de Mortalidade/Organização Pan Americana da Saúde. Utilizou-se modelo binomial negativo para estudar as tendências. Cerca de 121.297 mortes por homicídios (89% homens e 11% mulheres) ocorreram anualmente nas Américas, predominando as idades de 15 a 24 e de 25 a 39 anos. Em 2009, a taxa padronizada de homicídios da região foi 15,5/100.000. Os países com taxas/100.000 baixas foram Canadá (1,8), Argentina (4,4), Cuba (4,8), Chile (5,2) e Estados Unidos (5,8); e com taxas/100.000 altas foram El Salvador (62,9), Guatemala (51,2), Colômbia (42,5), Venezuela (33,2) e Porto Rico (25,8). Entre 1999-2009 as taxas da região permaneceram estáveis; aumentaram em nove países, como Venezuela (p < 0,001), Panamá (p < 0,001), El Salvador (p < 0,001) e Porto Rico (p < 0,001); diminuíram em quatro países, especialmente na Colômbia (p < 0,001); e permaneceram estáveis no Brasil, Estados Unidos, Equador e Chile. O aumento no México ocorreu no período mais recente. Apesar dos esforços empreendidos, diversos países têm taxas altas de homicídios e crescimento nas mesmas.

The scope of this study was to describe the magnitude and distribution of deaths by homicide in the Americas and to analyze the prevailing trends. Deaths by homicide (X85 to Y09 and Y35) were analyzed in 32 countries of the Americas Region from 1999 to 2009, recorded in the Mortality Information System/Pan American Health Organization. A negative binomial model was used to study the trends. There were around 121,297 homicides (89% men and 11% women) in the Americas, annually, predominantly in the 15 to 24 and 25 to 39 year age brackets. In 2009 the homicide age-adjusted mortality rate was 15.5/100,000 in the region. Countries with lower rates/100,000 were Canada (1.8), Argentina (4.4), Cuba (4.8), Chile (5.2), and the United States (5.8), whereas the highest rates/100,000 were in El Salvador (62.9), Guatemala (51.2), Colombia (42.5), Venezuela (33.2), and Puerto Rico (25.8). From 1999-2009, the homicide trend in the region was stable. They increased in nine countries: Venezuela (p<0.001), Panama (p<0.001), El Salvador (p<0.001), Puerto Rico (p<0.001); decreased in four countries, particularly in Colombia (p<0.001); and were stable in Brazil, the United States, Ecuador and Chile. The increase in Mexico occurred in recent years. Despite all efforts, various countries have high homicide rates and they are on the increase.

[Homicides in the Americas region: magnitude, distribution and trends, 1999-2009]. / Homicídios na região das Américas:magnitude, distribuição e tendências, 1999-2009

The scope of this study was to describe the magnitude and distribution of deaths by homicide in the Americas and to analyze the prevailing trends. Deaths by homicide (X85 to Y09 and Y35) were analyzed in 32 countries of the Americas Region from 1999 to 2009, recorded in the Mortality Information System/Pan American Health Organization. A negative binomial model was used to study the trends. There were around 121,297 homicides (89% men and 11% women) in the Americas, annually, predominantly in the 15 to 24 and 25 to 39 year age brackets. In 2009 the homicide age-adjusted mortality rate was 15.5/100,000 in the region. Countries with lower rates/100,000 were Canada (1.8), Argentina (4.4), Cuba (4.8), Chile (5.2), and the United States (5.8), whereas the highest rates/100,000 were in El Salvador (62.9), Guatemala (51.2), Colombia (42.5), Venezuela (33.2), and Puerto Rico (25.8). From 1999-2009, the homicide trend in the region was stable. They increased in nine countries: Venezuela (p<0.001), Panama (p<0.001), El Salvador (p<0.001), Puerto Rico (p<0.001); decreased in four countries, particularly in Colombia (p<0.001); and were stable in Brazil, the United States, Ecuador and Chile. The increase in Mexico occurred in recent years. Despite all efforts, various countries have high homicide rates and they are on the increase.

Bloqueantes alfa-1 adrenérgicos y síndrome de iris flácido intraoperatorio / Alpha1-adrenogenic blockers and intraoperative floppy iris syndrome

No disponible

The active (ADHa) and inactive (ADHi) forms of the PQQ-alcohol dehydrogenase from Gluconacetobacter diazotrophicus differ in their respective oligomeric structures and redox state of their corresponding prosthetic groups.

The membrane-bound alcohol dehydrogenase of Gluconacetobacter diazotrophicus contains one pyrroloquinoline quinone moiety (PQQ), one [2Fe-2S] cluster, and four c-type cytochromes. Here, we describe a novel and inactive enzyme. ADHi, similarly to ADHa, is a heterodimer of 72- and 44-kDa subunits and contains the expected prosthetic groups. However, ADHa showed a threefold molecular mass as compared to ADHi. Noteworthy, the PQQ, the [2Fe-2S] and most of the cytochromes in purified ADHi is in the oxidized form, contrasting with ADHa where the PQQ-semiquinone is detected and the [2Fe-2S] cluster as well as the cytochromes c remained fully reduced after purification. Reduction kinetics of the ferricyanide-oxidized enzymes showed that while ADHa was brought back by ethanol to its full reduction state, in ADHi, only one-quarter of the total heme c was reduced. The dithionite-reduced ADHi was largely oxidized by ubiquinone-2, thus indicating that intramolecular electron transfer is not impaired in ADHi. The acidic pH of the medium might be deleterious for the membrane-bound ADH by causing conformational changes leading to changes in the relative orientation of heme groups and shift of corresponding redox potential to higher values. This would hamper electron transfer resulting in the low activity observed in ADHi.

Mutation of SDHB is a cause of hypoxia-related high-altitude paraganglioma.

PURPOSE: Paragangliomas of the head and neck are neuroendocrine tumors and are associated with germ line mutations of the tricarboxylic acid cycle-related genes SDHB, SDHC, SDHD, and SDHAF2. Hypoxia is important in most solid tumors, and was directly implicated in tumorigenesis over 40 years ago when it was shown that dwelling at high altitudes increases the incidence of carotid body hyperplasia and paragangliomas. Although recent research has now elucidated several pathways of hypoxia in paragangliomas, nothing is currently known of the genetics or of gene-environment interactions in high-altitude paraganglioma. We postulated that SDH mutations might play a role in these tumors. EXPERIMENTAL DESIGN: Patients from a Mexican family, originating and resident in Guadalajara, were tested for mutations of SDHD, and subsequently, for mutations of SDHB followed by immunohistochemical confirmation of SDHB loss. RESULTS: Two patients, born and resident at altitudes of between 1,560 and 2,240 m, were found to have head and neck paragangliomas, including a remarkably aggressive recurrent tumor. Mutation analysis identified a pathogenic missense mutation in exon 7 of SDHB, c.689G>A, p.Arg230His, and loss of the SDHB protein was confirmed by immunohistochemistry. CONCLUSIONS: This is the first report of a SDH gene mutation in paraganglioma at high altitude. A rapidly recurrent head and neck paraganglioma is a very rare finding in an SDH mutation carrier, suggesting a gene-environment interaction. Neither patient showed evidence of sympathetic paraganglioma.

Rate of oxidant stress regulates balance between rat gastric mucosa proliferation and apoptosis.

We have characterized an experimental model of ethanol-induced chronic gastritis in which a compensatory mucosal cell proliferation is apparently regulated by lipoperoxidative events. Therefore, the present study is an attempt to further assess the participation of oxidant stress during gastric mucosa proliferation, by administering alpha-tocopherol (vitamin E) to rats with gastritis. A morphometric analysis was done, and parameters indicative of oxidant stress, cellular proliferation (including cyclin D1 levels), apoptotic events, and activities of endogenous antioxidant systems were measured in gastric mucosa from our experimental groups. After ethanol withdrawal, restitution of surface epithelium coincided with increased lipid peroxidation and cell proliferation and further active apoptosis. High alpha-tocopherol dosing (100 IU/kg bw) showed a clear antioxidant effect, abolished cell proliferation, and promoted an early and progressive apoptosis, despite vitamin E also enhancing levels of endogenous antioxidants. Indicators of cell proliferation inversely correlated with apoptotic events, and this relationship was blunted by administering vitamin E, probably by affecting translocation of active cyclin D1 into the nucleus. In conclusion, alpha-tocopherol administration inhibited cell proliferation, leading to a predominance of apoptotic events in ethanol-induced gastric damage. Therefore, the timing and magnitude of lipoperoxidative events seemed to synchronize in vivo cell proliferative and apoptotic events, probably by changing the cell redox state.

Eikenella corrodens: patogénesis y aspectos clínicos: [revisión] / Eikenella corrodens: pathogenesis and clinic aspects: [review]

El ambiente microbiológico oral es único y tiene una dinámica compleja. Se calcula que cerca de 500 especies de bacterias habitan la cavidad oral humana, y alrededor de 22 géneros son los predominantes. Las bacterias que se aíslan con más frecuencia de los sitios infectados de la cavidad oral, y que son también patógenos potenciales, forma un grupo pequeño de microorganismos gramnegativos, entre los que se incluyen los siguientes: Actinobacillus actinomycetemcomitans, Bacteroides forsythus, Campylobacter spp., Capnocytophoga spp., Eikenella corrodens, Fusobacterium nucleatum, Porphyromonas gingivalis, Prevotella intermedia y el grupo-Streptococcus milleri. E. corrodens se reconoce como un microbio patógeno oportunista en la cavidad oral; también, puede causar infecciones extra orales, como un agente infeccioso solo o en combinaciones con diversas bacterias. La presente revisión, con un énfasis en E. corrodens, mostrará varios aspectos de sus características microbiológicas y bioquímicas, también se sistematizan y discuten el conocimiento actual sobre los mecanismos de patogénesis, como los lipopolisacáridos, proteínas externas de membrana, complejo de adesina, pili y otros; infecciones oral y extra oral; factores predisponentes; endocarditis; osteomielitis, infecciones intra-abdominales; diagnóstico y agentes antimicrobianos.

The oral microbiological environment is unique and has a complex dynamic. It has been estimated that about 500 species of bacteria inhabit the human oral cavity and about 22 genera of them are the most dominant. The most frequently isolated from infected pockets of the oral cavity bacteria which are also potential pathogens form a small group of gramnegative microorganisms among which are included the following: Actinobacillus actinomycetemcomitans, Bacteroides forsythus, Campylobacter spp., Capnocytophoga spp., Eikenella corrodens, Fusobacterium nucleatum, Porphyromonas gingivalis, Prevotella intermedia, and Streptococcus milleri-group. E. corrodens is distinguished for being an opportunistic oral pathogen. It can also produce extra-oral infections acting either as an infectious agent itself or together with other bacteria. Referring to E. corrodens the present review will not only demonstrate different aspects about microbiological and biochemical characteristics, but also the actual knowledge on pathogenesis mechanism, like polysaccharides, outer membrane protein, lectin-like adhesin complex, pili, and other mechanisms will be systematized and discussed. Oral and extra-oral infections and other risking factors like endocarditis; osteomyelitis, intra-abdominal infections, their diagnosis and antimicrobial agents will be also considered in this paper.

Subsídios ao plano diretor de saúde e ambiente no âmbito do Sistema Único de Saúde / Contributions to the environment health plan in the scope of the Brazilian health system

O Grupo Temático de Saúde e Ambiente da Associação Brasileira de Pós-Graduação em Saúde Coletiva – ABRASCO – elaborou subsídios para um Plano Diretor de Saúde e Ambiente no Âmbito do Sistema Único de Saúde, na perspectiva de se estabelecer uma política intersetorial nesse tema. O presente artigo traz esta contribuição do grupo, abordando aspectos conceituais e operacionais, fruto de vários debates interdisciplinares ocorridos em diversas oficinas e consolidado em uma Oficina de Trabalho deste GT realizada em Brasília, no ano de 2003, durante o Congresso Brasileiro de Saúde Coletiva.