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A chimeric protein-based vaccine elicits a strong IgG antibody response and confers partial protection against Shiga toxin-producing Escherichia coli in mice
(Frontiers Media SA, 2023) Montero, David A.; Garcia-Betancourt, Richard; Vidal, Roberto M.; Velasco, Juliana; Palacios, Pablo A.; Schneider, Daniela; Vega, Carolina; Gómez, Leonardo; Montecinos, Hernán; Soto-Shara, Rodrigo; Oñate, Ángel; Carreño, Leandro J.
Background: Shiga toxin-producing Escherichia coli (STEC) is a foodborne pathogen that causes gastrointestinal infections, ranging from acute diarrhea and dysentery to life-threatening diseases such as Hemolytic Uremic Syndrome. Currently, a vaccine to prevent STEC infection is an unmet medical need. Results: We developed a chimeric protein-based vaccine targeting seven virulence factors of STEC, including the Stx2B subunit, Tir, Intimin, EspA, Cah, OmpT, and AggA proteins. Immunization of mice with this vaccine candidate elicited significant humoral and cellular immune responses against STEC. High levels of specific IgG antibodies were found in the serum and feces of immunized mice. However, specific IgA antibodies were not detected in either serum or feces. Furthermore, a significantly higher percentage of antigen-specific CD4+ T cells producing IFN-γ, IL-4, and IL-17 was observed in the spleens of immunized mice. Notably, the immunized mice showed decreased shedding of STEC O157:H7 and STEC O91:H21 strains and were protected against weight loss during experimental infection. Additionally, infection with the STEC O91:H21 strain resulted in kidney damage in control unimmunized mice; however, the extent of damage was slightly lower in immunized mice. Our findings suggest that IgG antibodies induced by this vaccine candidate may have a role in inhibiting bacterial adhesion and complement-mediated killing. Conclusion: This study provides evidence that IgG responses are involved in the host defense against STEC. However, our results do not rule out that other classes of antibodies also participate in the protection against this pathogen. Additional work is needed to improve the protection conferred by our vaccine candidate and to elucidate the relevant immune responses that lead to complete protection against this pathogen. Copyright © 2023 Montero, Garcia-Betancourt, Vidal, Velasco, Palacios, Schneider, Vega, Gómez, Montecinos, Soto-Shara, Oñate and Carreño.
A Cross-Sectional, Retrospective, and Comparative Study between Delirium and Non-Delirium Psychiatric Disorders in a Psychogeriatric Inpatient Population Referred to Consultation-Liaison Psychiatry Unit
(MDPI, 2023-04) Barra, Bernardo J.; Barahona, Maximiliano; Varela, Luis F.; Calvo, Pilar; Bastidas, Anna; Carreño, Jorge; Pintor, Luis
Background and objectives: Delirium is the most prevalent psychiatric disorder in inpatient older people. Its presence is associated with higher rates of institutionalization, functional disability and mortality. This study aims to evaluate delirium in a hospitalized psychogeriatric population, focusing on which factors predict the appearance of delirium, the impact it generates and the diagnostic concordance between non-psychiatric physicians and psychiatrists. Material and methods: This is an observational, cross-sectional, retrospective, and comparative study. We obtained data from a sample of 1017 patients (≥65 years) admitted to general hospital and referred from different services to the consultation-liaison psychiatry (CLP) unit. Logistic regression was performed using delirium as the dependent variable. To estimate the concordance of the diagnoses, the Kappa coefficient was used. To assess the impact of delirium, an ordinal regression, Wilcoxon median test and Fisher’s test were performed. Results: Delirium is associated with a higher number of visits, OR 3.04 (95% CI 2.38–3.88), longer length of stay and mortality, OR 2.07 (95% CI, 1.05 to 4.10). The model to predict delirium shows that being >75 years old has an OR of 2.1 (95% CI, 1.59–2.79), physical disability has an OR of 1.66 (95% CI, 1.25–2.20), history of delirium has an OR of 10.56 (95% CI, 5.26–21.18) and no use of benzodiazepines has an OR of 4.24 (95% CI, 2.92–6.14). The concordance between the referring physician’s psychiatric diagnosis and the psychiatrist CLP unit showed a kappa of 0.30. When analysing depression and delirium, the concordance showed Kappa = 0.46. Conclusions: Delirium is a highly prevalent psychiatric disorder, but it is still underdiagnosed, with low diagnostic concordance between non-psychiatric doctors and psychiatrists from CLP units. There are multiple risk factors associated with the appearance of delirium, which must be managed to reduce its appearance.
A functional survey of the enhancer activity of conserved non-coding sequences from vertebrate Iroquois cluster gene deserts
(Cold Spring Harbor Laboratory Press, 2005-08) De La Calle-Mustienes, E.; Feijoo, C.; Manzanares, M.; Tena, J.; Rodriguez-Seguel, E.; Letizia, A.; Allende, M.; Gomez-Skarmeta, J.
Recent studies of the genome architecture of vertebrates have uncovered two unforeseen aspects of its organization. First, large regions of the genome, called gene deserts, are devoid of protein-coding sequences and have no obvious biological role. Second, comparative genomics has highlighted the existence of an array of highly conserved non-coding regions (HCNRs) in all vertebrates. Most surprisingly, these structural features are strongly associated with genes that have essential functions during development. Among these, the vertebrate Iroquois (Irx) genes stand out on both fronts. Mammalian Irx genes are organized in two clusters (IrxA and IrxB) that span >1 Mb each with no other genes interspersed. Additionally, a large number of HCNRs exist within Irx clusters. We have systematically examined the enhancer activity of HCNRs from the IrxB cluster using transgenic Xenopus and zebrafish embryos. Most of these HCNRs are active in subdomains of endogenous Irx expression, and some are candidates to contain shared enhancers of neighboring genes, which could explain the evolutionary conservation of Irx clusters. Furthermore, HCNRs present in tetrapod IrxB but not in fish may be responsible for novel Irx expression domains that appeared after their divergence. Finally, we have performed a more detailed analysis on two IrxB ultraconserved non-coding regions (UCRs) duplicated in IrxA clusters in similar relative positions. These four regions share a core region highly conserved among all of them and drive expression in similar domains. However, inter-species conserved sequences surrounding the core, specific for each of these UCRs, are able to modulate their expression. ©2005 by Cold Spring Harbor Laboratory Press.
A look at the safety of ultrasound in obstetric echotomography
(Sociedad Chilena de Obstetricia y Ginecologia, 2022-07) Jeldes Maturana, Jorge; Ramírez Peña, Rodrigo; Zúñiga Clavijo, Patricia; Ogalde Baeza, Sebastián; Miño Cornejo, José S.; Fuentes Alburquenque, Mauricio; Pastén Avalos, Miriam; Canals Lambarri, Mauricio
The thermal and mechanical indices are the best estimators of fetal risk in an ultrasound and their values should be controlled in order to minimize exposure as much as possible. We compared the values of the thermal and mechanical indices obtained in obstetric ultrasound examinations of pregnant patients, with the value recommended by the international community. These indices were estimated in 421 obstetric ultrasounds during 2019. The estimated values were compared with each other and with the recommended value for each index and according to the display mode (B, color Doppler and spectral Doppler). Of the total sample, for the thermal index in color Doppler mode, 0.24% exceeded the recommended standard value and 2.85%. in spectral Doppler mode. For the mechanical index, the recommended value was exceeded in B mode by 11.16%, in 8.08% in color Doppler mode and, finally, by 0.48% for spectral Doppler mode. The mechanical and thermal indices in this sample of obstetric ultrasound examinations are on average below the reference value. However, there is a significant number of cases in which the standards are exceeded, which should be a warning to the medical community. © 2022 Sociedad Chilena de Obstetricia y Ginecología. Publicado por Permanyer. Este es un artículo open access bajo la licencia CC BY-NC-ND (https://creativecommons.org/licenses/by-nc-nd/4.0/).
A Multicenter Study Evaluating the Stages of Change in Food Consumption with Warning Labels among Chilean University Students
(Hindawi Limited, 2020) Durán Agüero, S.; Araneda, J.; Ahumada, D.; Silva Rojas, J.; Bonacich, R.; Caichac, A.; Salamanca, M.; Villarroel, P.; Fernandez, E.; Pacheco, V.; Martinovic, P.; Wilson, W.; Neira, A.; Encina, C.; Tillería, J.
To analyze the stage of change in food consumption with warning labels among Chilean university students. Materials and Methods. Cross-sectional study which applied surveys in universities from all over the country. Study included 4807 participants of 18 to 40 years of both sexes who were asked about the level of knowledge of the new food law and food consumption with warning signals, including questions regarding their willingness to behavior change according to Prochaska's transtheoretical model. To compare continuous variables, Student's t-test was used in the statistical package SPSS 22.0, and p <0.05 was considered a significant difference. Results. Of the total number of respondents, 99.3% of the students indicated that they know about the food law, classifying foods with signals in the precontemplation stage. Compared by sex, we observed that women give greater importance to behavior change in all of foods (p <0.001). Underweight students give less importance to change in unhealthy foods, while obesity students give more importance but do not show more confidence in behavior change (p <0.05). Conclusion. The university students show a low importance and confidence to make behavior change, aspects associated with sex and nutritional status. It is necessary to strengthen nutritional food education and not just talk about structural measures.
A multifactorial approach of nutritional, intellectual, brain development, cardiovascular risk, socio-economic, demographic and educational variables affecting the scholastic achievement in Chilean students: An eight- year follow-up study
(Public Library of Science, 2019-02) Ivanovic, Daniza M.; Almagià, Atilio F.; Arancibia, Violeta C.; Ibaceta, Camila V.; Arias, Vanessa F.; Rojas, Tatiana R.; Flores, Ofelia C.; Villagrán, Francisca S.; Tapia, Liliana U.; Acevedo, Javiera A.; Morales, Gladys I.; Martínez, Víctor C.; Larraín, Cristián G.; Silva, Claudio F.A.; Valenzuela, Rodrigo B.; Barrera, Cynthia R.; Billeke, Pablo B.; Zamorano, Francisco M.; Orellana, Yasna Z.
The aim of this study was to quantitate the relative impact of nutritional, intellectual, brain development, cardiovascular risk, socio-economic, demographic and educational variables on the results of the 2009 Quality Education Measurement System (SIMCE) tests of language and mathematics for scholastic achievement (SA) applying a multifactorial approach, in school-age children of the 2010 5 th elementary school grade (5ESG) and of the 1 st grade of high school (1HSG). The purposes were: i) to test the hypothesis that intellectual ability, the level of SA of the educational establishments in the 2009 SIMCE tests, sex, parental schooling levels, and head circumference-for-age Z-score are the most relevant parameters associated with 2009 SIMCE outcomes; ii) to determine the predictive ability of the 2009 SIMCE results in determining the 2013 SIMCE outcomes for the 2010 5ESG cohort (when they graduated from elementary school, 8 th grade) and for determining the 2013 University Selection Test (PSU) outcomes for the 2010 1HSG group (for university admission, when they graduated from high school, 4 th grade); iii) to determine the association between the 2009 SIMCE results with the 2017 PSU outcomes for the 2010 5ESG group (for university admission, when they graduated from high school, 4 th grade). A representative, proportional and stratified sample of 33 schools of the Metropolitan Region of Chile was randomly chosen. In these schools, 1,353 school-age children of both sexes, of the 2010 5ESG (n = 682; mean age = 10.8 years, SD = 0.6) and of the 2010 1HSG (n = 671; mean age = 14.8 years, SD = 0.6) participated. In both grades and tests, the findings confirm the hypotheses formulated. 2009 SIMCE outcomes were positively and significantly associated with 2013 SIMCE and with 2017 PSU and, with 2013 PSU outcomes in school-age children from 2010 5ESG and 1HSG, respectively. These findings may be useful for educational and health planning in Chile and countries in a comparable stage of development. © 2019 Ivanovic et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
A myosin Va mutant mouse with disruptions in glutamate synaptic development and mature plasticity in visual cortex
(Society for Neuroscience, 2013-05) Yoshii, A.; Zhao, J.; Pandian, S.; van Zundert, B.; Constantine-Paton, M.
Myosin Va (MyoVa) mediates F-actin-based vesicular transport toward the plasma membrane and is found at neuronal postsynaptic densities (PSDs), but the role of MyoVa in synaptic development and function is largely unknown. Here, in studies using the dominantnegative MyoVa neurological mutant mouse Flailer, we find that MyoVa plays an essential role in activity-dependent delivery of PSD-95 and other critical PSD molecules to synapses and in endocytosis of AMPA-type glutamate receptors (AMPAR) in the dendrites of CNS neurons. MyoVa is known to carry a complex containing the major scaffolding proteins of the mature PSD, PSD-95, SAPAP1/GKAP, Shank, and Homer to dendritic spine synapses. In Flailer, neurons show abnormal dendritic shaft localization of PSD-95, stargazin, dynamin3, AMPARs and abnormal spine morphology. Flailer neurons also have abnormally highAMPARminiature current frequencies and spontaneous AMPAR currents that are more frequent and larger than in wild-type while numbers of NMDAR containing synapses remain normal. The AMPAR abnormalities are consistent with a severely disrupted developmental regulation of long-term depression that we find in cortical Flailer neurons. Thus MyoVa plays a fundamentally important role both in localizing mature glutamate synapses to spines and in organizing the synapse for normal function. For this reason Flailer mice will be valuable in further dissecting the role of MyoVa in normal synaptic and circuit refinement and also in studies of neurological and neuropsychiatric diseases where disruptions of normal glutamate synapses are frequently observed.
A new species of Liolaemus related to L. nigroviridis from the Andean highlands of Central Chile (Iguania, Liolaemidae)
(PENSOFT PUBL, 2016-01) Troncoso-Palacios, J.; Elorza, A.; Puas, German I.; Alfaro-Pardo, E.
The Liolaemus nigroviridis group is a clade of highland lizards endemic to Chile. These species are distributed from northern to central Chile, and currently there are no cases of sympatric distribution. This study describes a new species, Liolaemus uniformis sp. n., from this group, and provides a detailed morphological characterization and mitochondrial phylogeny using cytochrome-b. Liolaemus uniformis was found in sympatry with L. nigroviridis but noticeably differed in size, scalation, and markedly in the color pattern, without sexual dichromatism. This new species has probably been confused with L. monticola and L. bellii, both of which do not belong to the nigroviridis group. The taxonomic issues of this group that remain uncertain are also discussed.
A novel high-throughput assay for islet respiration reveals uncoupling of rodent and human islets
(Public Library of Science (PLoS), 2012-05) Wikstrom, J.; Sereda, S.; Stiles, L.; Elorza, A.; Allister, E.; Neilson, A.; Ferrick, D.; Wheeler, M.; Shirihai, O.
The pancreatic beta cell is unique in its response to nutrient by increased fuel oxidation. Recent studies have demonstrated that oxygen consumption rate (OCR) may be a valuable predictor of islet quality and long term nutrient responsiveness. To date, high-throughput and user-friendly assays for islet respiration are lacking. The aim of this study was to develop such an assay and to examine bioenergetic efficiency of rodent and human islets. Methodology/Principal Findings: The XF24 respirometer platform was adapted to islets by the development of a 24-well plate specifically designed to confine islets. The islet plate generated data with low inter-well variability and enabled stable measurement of oxygen consumption for hours. The F1F0 ATP synthase blocker oligomycin was used to assess uncoupling while rotenone together with myxothiazol/antimycin was used to measure the level of non-mitochondrial respiration. The use of oligomycin in islets was validated by reversing its effect in the presence of the uncoupler FCCP. Respiratory leak averaged to 59% and 49% of basal OCR in islets from C57Bl6/J and FVB/N mice, respectively. In comparison, respiratory leak of INS-1 cells and C2C12 myotubes was measured to 38% and 23% respectively. Islets from a cohort of human donors showed a respiratory leak of 38%, significantly lower than mouse islets. Conclusions/Significance: The assay for islet respiration presented here provides a novel tool that can be used to study islet mitochondrial function in a relatively high-throughput manner. The data obtained in this study shows that rodent islets are less bioenergetically efficient than human islets as well as INS1 cells.
A Novel Low-Cost Sensor Prototype for Nocturia Monitoring in Older People
(Institute of Electrical and Electronics Engineers Inc., 2018-09) Taramasco, C.; Rodenas, T.; Martinez, F.; Fuentes, P.; Munoz, R.; Olivares, R.; Albuquerque, V.H.C.; Demongeot, J.
Nocturia is frequently defined as the necessity to get out of bed at least one time during the night to urinate, with each of these episodes being preceded and continued by sleep. Several studies suggest that an increase of nocturia is seen with the onset of age, occurring in around 70% of adults over the age of 70. Its appearance is associated with detrimental quality of life for those who present nocturia, since it leads to daytime sleepiness, cognitive dysfunction, among others. Currently, a voiding diary is necessary for nocturia assessment; these are prone to bias due to their inherent subjectivity. In this paper, we present the design of a low-cost device that automatically detects micturition events. The device obtained 73% in sensibility and 81% in specificity; these results show that systems such as the proposed one can be a valuable tool for the medical team when evaluating nocturia. © 2013 IEEE.
A novel monitoring system for fall detection in older people
(2169-3536, 2018-07) Taramasco, C.; Rodenas, T.; Martinez, F.; Fuentes, P.; Munoz, R.; Olivares, R.; De Albuquerque, V.H.C.; Demongeot, J.
Each year, more than 30% of people over 65 years-old suffer some fall. Unfortunately, this can generate physical and psychological damage, especially if they live alone and they are unable to get help. In this field, several studies have been performed aiming to alert potential falls of the older people by using different types of sensors and algorithms. In this paper, we present a novel non-invasive monitoring system for fall detection in older people who live alone. Our proposal is using very-low-resolution thermal sensors for classifying a fall and then alerting to the care staff. Also, we analyze the performance of three recurrent neural networks for fall detections: Long short-term memory (LSTM), gated recurrent unit, and Bi-LSTM. As many learning algorithms, we have performed a training phase using different test subjects. After several tests, we can observe that the Bi-LSTM approach overcome the others techniques reaching a 93% of accuracy in fall detection. We believe that the bidirectional way of the Bi-LSTM algorithm gives excellent results because the use of their data is influenced by prior and new information, which compares to LSTM and GRU. Information obtained using this system did not compromise the user's privacy, which constitutes an additional advantage of this alternative. © 2013 IEEE.
A proposed new bacteriophage subfamily: “Jerseyvirinae”
(Springer-Verlag Wien, 2015-04) Anany, Hany; Switt, Andrea I. Moreno; De Lappe, Niall; Ackermann, Hans-Wolfgang; Reynolds, Darren M.; Kropinski, Andrew M.; Wiedmann, Martin; Griffiths, Mansel W.; Tremblay, Denise; Moineau, Sylvain; Nash, John H. E.; Turner, Dann
Based on morphology and comparative nucleotide and protein sequence analysis, a new subfamily of the family Siphoviridae is proposed, named “Jerseyvirinae” and consisting of three genera, “Jerseylikevirus”, “Sp3unalikevirus” and “K1glikevirus”. To date, this subfamily consists of 18 phages for which the genomes have been sequenced. Salmonella phages Jersey, vB_SenS_AG11, vB_SenS-Ent1, vB_SenS-Ent2, vB_SenS-Ent3, FSL SP-101, SETP3, SETP7, SETP13, SE2, SS3e and wksl3 form the proposed genus “Jerseylikevirus”. The proposed genus “K1glikevirus” consists of Escherichia phages K1G, K1H, K1ind1, K1ind2 and K1ind3. The proposed genus “Sp3unalikevirus” contains one member so far. Jersey-like phages appear to be widely distributed, as the above phages were isolated in the UK, Canada, the USA and South Korea between 1970 and the present day. The distinguishing features of this subfamily include a distinct siphovirus morphotype, genomes of 40.7-43.6 kb (49.6-51.4 mol % G+C), a syntenic genome organisation, and a high degree of nucleotide sequence identity and shared proteins. All known members of the proposed subfamily are strictly lytic. © 2015, Springer-Verlag Wien.
A putative RNA editing from U to C in a mouse mitochondrial transcript
(Oxford University Press, 2002-05) Villegas, J.; Müller, I.; Arredondo, J.; Pinto, R.; Burzio, L.O.
Recently, we isolated and characterized a new mouse mitochondrial RNA molecule containing the mitochondrial 16S RNA plus 121 nt joined to the 5′ end of the RNA. This fragment arises from the L strand of the same gene and we have named this transcript chimeric RNA. At position 121 of the RNA there is a C, which, according to the sequence of the mitochondrial 16S RNA gene, should be a U. We hypothesized that this RNA is synthesized having a U at position 121, which is later substituted to a C by a putative editing reaction. Based on the presence of sites for the restriction endonucleases RsaI and Fnu4HI around position 121, both forms of the RNA were detected in mouse tissues. To confirm the presence of the non-edited and putative edited RNA, a fragment containing the first 154 nt of the RNA was amplified by RT–PCR and cloned. The substitution of U for C was demonstrated by sequencing these clones. In vitro transcription experiments demonstrated that the substitution of U for C is not due to artifact of amplification or cloning. Moreover, in mitochondria from testis only the non-edited form was found. This, together with other experimental evidence, demonstrated that the base substitution was not due to polymorphism of the mitochondrial 16S RNA gene. This is the first demonstration of a substitution reaction from U to C in a mammalian mitochondrial transcript.
A room for doubt in the classifications of pathos: From crazy studies to the return of the account from madness
(Associacao Universitaria de Pesquisa em Psicopatologia Fundamental, 2022) Suarez, Raudelio Machín; Collao, Fernanda Castro
A solvent-free thermosponge nanoparticle platform for efficient delivery of labile proteins
(Nano Letters, 2014-11) Choi, Won Ila; Kamaly, Nazilaa; Riol-Blanco, Lorenab; Lee, In-Hyuna; Wu, Juna; Swami, Archanaa; Vilos, Cristiana, c; Yameen, Basita; Yu, Mikyunga; Shi, Jinjuna; Tabas, Irad, e, f; Von Andrian, Ulrich H.; Jon, Sangyongg; Farokhzad, Omid C.
Protein therapeutics have gained attention recently for treatment of a myriad of human diseases due to their high potency and unique mechanisms of action. We present the development of a novel polymeric thermosponge nanoparticle for efficient delivery of labile proteins using a solvent-free polymer thermo-expansion mechanism with clinical potential, capable of effectively delivering a range of therapeutic proteins in a sustained manner with no loss of bioactivity, with improved biological half-lives and efficacy in vivo. © 2014 American Chemical Society.
A standardized objective structured clinical examination to assess clinical competencies in medical students
(Sociedad Medica de Santiago, 2018-12) Behrens, Claudia; Morales, Verónica; Parra, Paula; Hurtado, Amelia; Fernández, Rosario; Giaconi, Elisa; Santelices, Lucía; Armijo, Soledad; Furman, Gail
Background: Outcomes-based education is a trend in medical education and its assessment is one of the main challenges. The Objective Structured Clinical Examination (OSCE) is one of the tools used to assess clinical competencies. Although Chilean medical schools have used OSCEs for 18 years, there is a vast variability in the way these examinations are administered. Aim: To design and implement an integrated OSCE to assess clinical competencies at the end of the medical program in Chilean medical schools, aiming to reduce variability between these schools. Material and Methods: Seven medical schools, supported by experts from the National Board of Medical Examiners, designed a 12 station OSCE to measure clinical outcomes at the end of the seventh year of medical training. Unlike traditional OSCEs, this new examination incorporated the assessment of clinical reasoning and communication skills, evaluated from patients’ perspective. Results: One hundred twenty-five volunteers took the same exam at five different venues. The internal consistency was 0.62. Following a compensatory approach, 85% of students passed the exam. Communication assessment showed poorer results than those reported in the literature. Conclusions: Among Chilean medical students, the assessment of clinical outcomes in a collaborative way, through a valid and reliable exam, is feasible. A consensus on how to teach and assess clinical reasoning across the medical curriculum is required. The assessment of students’ communication skills requires further development. © 2018, Sociedad Medica de Santiago. All rights reserved.
Aberrant T cell immunity triggered by human respiratory syncytial virus and human metapneumovirus infection
(Taylor and Francis, 2017-08) González, A.E.; Lay, M.K.; Jara, E.L.; Espinoza, J.A.; Gómez, R.S.; Soto, J.; Rivera, C.A.; Abarca, K.; Bueno, S.M.; Riedel, C.A.; Kalergis, A.M.
Human Respiratory syncytial virus (hRSV) and human metapneumovirus (hMPV) are the two major etiological viral agents of lower respiratory tract diseases, affecting mainly infants, young children and the elderly. Although the infection of both viruses trigger an antiviral immune response that mediate viral clearance and disease resolution in immunocompetent individuals, the promotion of long-term immunity appears to be deficient and reinfection are common throughout life. A possible explanation for this phenomenon is that hRSV and hMPV, can induce aberrant T cell responses, which leads to exacerbated lung inflammation and poor T and B cell memory immunity. The modulation of immune response exerted by both viruses include different strategies such as, impairment of immunological synapse mediated by viral proteins or soluble factors, and the induction of pro-inflammatory cytokines by epithelial cells, among others. All these viral strategies contribute to the alteration of the adaptive immunity in order to increase the susceptibility to reinfections. In this review, we discuss current research related to the mechanisms underlying the impairment of T and B cell immune responses induced by hRSV and hMPV infection. In addition, we described the role each virulence factor involved in immune modulation caused by these viruses. © 2017 Taylor & Francis.
Academic achievement, engagement and burnout among first year medical students
(Sociedad Medica de Santiago, 2015-07) Gómez H, Paula; Pérez V., Cristhian; Parra P., Paula; Ortiz M., Liliana; Matus B., Olga; McColl C., Peter; Torres A., Graciela; Meyer K., Andrea
Background: Stress may affect the sense of wellbeing and academic achievement of university students. Aim: To assess the relationship of academic engagement and burnout with academic achievement among first year medical students. Material and Methods: The Utrecht Work Engagement Scale-Student and Maslach Burnout Inventory Student Survey (MBI-SS) were applied to 277 first year medical students of four universities. Their results were correlated with the grades obtained in the different courses. Results: Moderately high engagement and low burnout levels were detected. There was a high level of satisfaction with studies and a moderate exhaustion level. Academic achievement was associated with the degree of engagement with studies but not with burnout. Conglomerate analysis detected a group of students with high levels of wellbeing, characterized by high levels of academic engagement and low burnout. Other group had moderate levels of engagement and lack of personal fulfilment. Other group, identified as extenuated, had high levels of personal exhaustion and depersonalization. Finally the disassociated group had a low academic engagement, low emotional exhaustion, high levels of depersonalization and lack of personal fulfillment. Conclusions: Academic achievement is associated with the level of engagement with studies but not with burnout. © 2015, Sociedad Medica de Santiago. All rights reserved.
Actualización en el diagnóstico y terapéutica en hipertensión pulmonar arterial
(Sociedad Médica de Santiago, 2006) Zagolin B., Mónica; Wainstein G., Eduardo; Uriarte G., Polentzi
Resumen: Pulmonary Arterial Hypertension includes a heterogeneous group of disorders with a common genetic, pathological and hemodinamyc origin. It is characterized by a high pulmonary artery pressure due to a primary vascular disease, as a consequence of genetic and environmental factors. The common pathway is a vascular imbalance towards vasoconstriction and proliferation inside the small vessels. According to the World Health Organization, 2003, Pulmonary Arterial Hypertension is classified as idiopathic, familiar or associated to connective tissue diseases, HIV, drugs, porto-pulmonary hypertension, congenital intracardiac shunts and others. The diagnosis is based in hemodynamics. Echocardiogram is a non invasive and right ventricular catheterization is an invasive diagnostic tool. Follow up is based on a clinical and functional assessment through functional class classification, dyspnea scores and 6-minute walking test. The prognosis is historically devastating but new therapies are changing the natural history of the disease. New treatments have demonstrated improvement in symptoms, hemodynamic profiles and survival. Intravenous, subcutaneous or inhaled prostanoids such as Epoprostenol, Treprostinil or Iloprost respectively have been approved for Pulmonary Arterial Hypertension treatment as well as oral endothelial receptor blockers. They are all considered first line treatments for arterial pulmonary hypertensive patients with even better benefits than lung transplantation. Phosphodiesterase inhibitors (Sildenafil), have been recently approved for the treatment of pulmonary arterial hypertension.
Acute effect of caffeine ingestion on reaction time and electromyographic activity of the dollyo chagi round kick in taekwondo fighters
(Revista Internacional de Ciencias del Deporte, 2017-01) Cortez, Luis; Mackay, Karen; Contreras, Edwin; Peñailillo, Luis
Caffeine is considered an enhancing aid and most consumed in sports, mainly due to its stimulant properties on the central nervous system, improving athletic performance and decreasing muscle fatigue. Objective: The aim of this study was to investigate the acute effect of caffeine on the reaction time and muscle activity of a Dollyo Chagi kick in taekwondo fighters. Methods: Thirteen taekwondo fighters ingested either 5 mg of caffeine per kg of body mass or a placebo. Reaction time and muscle activity were measured 60 min before the intake of caffeine or placebo, 60 min after ingestion and after a fatigue stimuli. Surface electromyogram (sEMG) amplitude, and time of reaction of the muscles rectus femoris, vastus lateralis, vastus medialis and biceps femoris during a circular kick related to a sound stimulus were measured. Results: Caffeine ingestion decreased the reaction time of the rectus femoris muscle 60-minutes after ingestion of caffeine and after strenuous stimulation (P<0.05). No significant decrease in reaction time was observed in other muscles. Furthermore, no changes in muscles activity in any other muscles were found. Conclusion: Caffeine supplementation in taekwondo athletes could reduce the reaction time of a Dollyo Chagi round kick after 60 minutes of ingestion and after a fatigue stimuli.

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